WO2017004078A1

WO2017004078A1 - Vehicle energy-storage systems

Info

Publication number: WO2017004078A1
Application number: PCT/US2016/039884
Authority: WO
Inventors: Nicholas John Sampson; W. Porter HARRIS; Blake ROSENGREN; Anil Paryani; Omourtag Alexandrov VELEV; Douglas D. CHIDESTER; Steven Harold OFFUTT; Hrayr TOROSYAN
Original assignee: Faraday&Future Inc.
Priority date: 2015-06-30
Filing date: 2016-06-28
Publication date: 2017-01-05

Abstract

The present disclosure is directed to energy storage systems for vehicles. In some aspects, the energy storage system may be used to power an electric automobile. The energy storage system may include a plurality of individual battery cells. The cells may be cylindrical and have a positive and negative terminal on the same side. The cells may be physically and/or electrically organized into bricks. The bricks may be physically and/or electrically organized into modules. The modules may be physically and/or electrically organized into strings. The strings may be physically and/or electrically organized into a pack. In some embodiments, packs, strings, modules and/or bricks may include flexible circuitry and/or may be liquid cooled.

Description

VEHICLE ENERGY-STORAGE SYSTEMS

FIELD

[0001] The present application relates generally to energy- storage systems, and more specifically to energy-storage systems for vehicles.

BACKGROUND

[0002] Electric-drive vehicles may reduce the impact of fossil-fuel engines on the environment and increase the sustainability of automotive modes of transportation. Energy- storage systems are essential for electric-drive vehicles, such as hybrid electric vehicles, plug-in hybrid electric vehicles, and all-electric vehicles. Size, efficiency, and safety are important considerations for these energy-storage systems. Spatially efficient storage, improved thermal management, and balance among battery cells, promote these goals.

SUMMARY

[0003] The systems and methods of this disclosure each have several innovative aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope as expressed by the claims that follow, its more prominent features will now be discussed briefly. The electrical and mechanical arrangement of the components described herein have several advantages over the prior art. For example, the individual battery cells may be subject to less cycling, thus increasing battery lifetime. The individual batteries cells may include terminals on only one end of a cylindrical body - simplifying manufacturing. The configurations of battery cells within liquid cooled modules may provide increased energy storage density.

[0004] In some embodiments, modular energy-storage systems are described. An electric vehicle battery pack may include a plurality of independently removable battery strings. Each battery string may include a plurality of battery modules. Each battery module may include a plurality of electrochemical cells. The cells may be organized into rows and columns. In some aspects, cells are electrically coupled in parallel and/or in series. The electrochemical cells may be disposed within various cell holder structures, and may be electrically connected by flexible circuitry. Coupling of various components within the battery pack, strings, and/or modules may be accomplished by pressure fitting, snap fitting, welding such as laser welding, application of adhesive chemicals, or other coupling methods. In some embodiments, battery packs, strings, and/or modules may be liquid cooled.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The above-mentioned aspects, as well as other features, aspects, and advantages of the present technology will now be described in connection with various implementations, with reference to the accompanying drawings. The illustrated implementations are merely examples and are not intended to be limiting. Throughout the drawings, similar symbols typically identify similar components, unless context dictates otherwise.

[0006] FIG. 1 is a block diagram of an exemplary electric vehicle drive system according to one embodiment.

[0007] FIG. 2 is block diagram of exemplary voltage source and battery management system according to one embodiment.

[0008] FIG. 3 is another block diagram of exemplary voltage source and battery management system according to one embodiment.

[0009] FIG. 4 is a diagrammatic illustration of an exemplary electric vehicle having an exemplary battery pack.

[0010] FIG. 5A is a diagrammatic illustration of the exemplary battery pack of FIG. 4 when removed from the electric vehicle.

[0011] FIG. 5B is a diagrammatic illustration of the exemplary battery pack of FIG. 5A disposed in an exemplary enclosure.

[0012] FIGS. 6A and 6B are diagrammatic illustrations of exemplary coolant flow paths in the exemplary battery back of FIG. 5A. FIG. 6B is an enlarged module of the battery pack depicted in FIG. 6A.

[0013] FIG. 7A and 7B are diagrammatic illustrations of an exemplary coupling arrangement between two exemplary battery modules shown apart in FIG. 7A and coupled together in FIG. 7B. A plurality of modules may be joined together as shown, for example, in FIG. 5A

[0014] FIG. 8 is a diagrammatic illustration of the internal components of the module of FIG. 7A. [0015] FIG. 9 is a diagrammatic illustration of an exemplary battery module of FIG. 8 with the current carrier and battery cells removed from one of the half modules of the battery module.

[0016] FIG. 10 is a diagrammatic illustration of an exemplary battery module of FIG. 8 with the current carrier removed from one of the half modules of the battery module.

[0017] FIG. 11 is a diagrammatic illustration of an exemplary half module.

[0018] FIG. 12 is a diagrammatic illustration of an exemplary battery cell.

[0019] FIG. 13 is a diagrammatic illustration of an exemplary current carrier.

[0020] FIG. 14 is a diagrammatic illustration of an exemplary current carrier.

[0021] FIG. 15 is a front view of the exemplary current carrier of FIG. 14.

[0022] FIG. 16 is a side view of an exemplary current carrier of FIG. 14.

[0023] FIG. 17 is a detailed diagrammatic illustration of an exemplary current carrier.

[0024] FIG. 18A is an exploded view of an exemplary current carrier.

[0025] FIG. 18B is another exploded view of an exemplary current carrier.

[0026] FIG. 18C is a detailed diagrammatic illustration of the circuit design of an exemplary current carrier.

[0027] FIG. 19 depicts an exploded view of a battery module, in accordance with various embodiments.

[0028] FIGS. 20A-C depict various perspective views of a blast plate, according to some embodiments, that may be included in a battery module, as shown for example in FIG. 19

[0029] FIG. 21 illustrates a perspective view of a half shell of a battery module, according to various embodiments.

[0030] FIG. 22 depicts a cross-sectional view of a battery module, in accordance with some embodiments.

[0031] FIG. 23 shows a simplified flow diagram for a process for assembling a battery module, according to some embodiments.

[0032] FIGS. 24A-B depict perspective view of a battery pack enclosure and a plurality of modular battery strings in accordance with an exemplary embodiment. [0033] FIGS. 25A depicts a top perspective exterior views of a modular battery string in accordance with an exemplary embodiment.

[0034] FIG. 25B is a bottom perspective view of the modular battery string of FIG. 25A. Such strings may be mounted in a rack as shown in FIGS. 24A-24B.

[0035] FIG. 25C schematically illustrates various components of a modular battery string in accordance with an exemplary embodiment.

[0036] FIG. 26 is a partial process flow diagram for assembly of battery modules according to an exemplary implementation.

[0037] FIG. 27 is a partial process flow diagram for assembly of battery modules according to an exemplary implementation.

[0038] FIG. 28 is a partial process flow diagram for assembly of battery modules according to an exemplary implementation. Inputs A and B may continue from FIGS. 26- 27. Input C may continue from FIG. 29. Output D may continue to FIG. 30.

[0039] FIG. 29 is a partial process flow diagram for assembly of battery modules according to an exemplary implementation.

[0040] FIG. 30 is a partial process flow diagram for assembly of battery modules according to an exemplary implementation. Output E may continue to FIG. 31.

[0041] FIG. 31 is a partial process flow diagram for assembly of battery modules according to an exemplary implementation. Input F may continue from FIG. 32. Output G may continue to FIG. 33.

[0042] FIG. 32 is a partial process flow diagram for assembly of battery modules according to an exemplary implementation.

[0043] FIG. 33 is a partial process flow diagram for assembly of battery modules according to an exemplary implementation. Output H may continue to FIG. 34.

[0044] FIG. 34 is a partial process flow diagram for assembly of battery modules according to an exemplary implementation. Output I may continue to FIG. 35.

[0045] FIG. 35 is a partial process flow diagram for assembly of battery modules according to an exemplary implementation.

[0046] FIG. 36 is an exploded perspective view of an exemplary battery module.

[0047] FIG. 37A is a perspective view of an exemplary cylindrical battery cell. [0048] FIG. 37B is an end view of an exemplary battery cell

[0049] FIG. 38 is a perspective view of the exemplary module shell of FIG. 36 with a circuit board and copper bar.

[0050] FIG. 39 is a perspective view of the exemplary module shell of FIG. 38 with an accelerator applied.

[0051] FIG. 40 is a top view of the exemplary module shell of FIG. 39 with an accelerator and a maskant applied.

[0052] FIG. 41 is a perspective view of the exemplary module shell of FIG. 40 illustrating the insertion of battery cells into the module shell.

[0053] FIG. 42 is a side cross-sectional view of an exemplary battery cell mounted in a bottom battery cell retainer plate of a module.

[0054] FIG. 43A is a perspective view of an exemplary top battery cell retainer plate and a flexible circuit showing how they are assembled.

[0055] FIG. 43B is a perspective view of an exemplary assembled top battery cell retainer plate and flexible circuit.

[0056] FIG. 44A is a perspective view of the exemplary module shell of FIG. 41 filled with battery cells and an assembled top battery cell retainer plate and flexible circuit showing how they are assembled.

[0057] FIG. 44B is a top view of the exemplary assembled module shell of FIG. 44A having thetop battery cell retainer plate and flexible circuit attached therto.

[0058] FIG. 45 is a perspective view of the exemplary assembled module shell of FIG. 44B having a cover attached therto.

[0059] FIG. 46A is a perspective view of theexemplary assembled battery module of FIG. 44B having O-rings inserted over ports in the module.

[0060] FIG. 46B is a partial enlarged perspective view of FIG. 46A with O-rings in place.

[0061] FIG. 47 is a flow diagram of an exemplary method for assembly of a battery module.

[0062] FIG. 48 is a flow diagram of an exemplary method for assembly of a battery module. [0063] FIG. 49 is a flow diagram of an exemplary method for assembly of a battery module.

DETAILED DESCRIPTION

[0064] The following description is directed to certain implementations for the purpose of describing the innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. FIGS. 1-49 illustrate exemplary components, methods, and systems for use in electric vehicles. Exemplary systems may include a battery pack organized as strings having current carriers and battery modules. Such systems may be implemented in any type of vehicle. For example, the vehicle may be a car, truck, semi-truck, motorcycle, plane, train, moped, scooter, or other type of transportation. Furthermore, the vehicle may use many types of powertrain. For example, the vehicle may be an electric vehicle, a fuel cell vehicle, a plug-in electric vehicle, a plug-in hybrid electric vehicle, or a hybrid electric vehicle. Though described with reference to vehicle components, the exemplary current carriers and battery modules are not limited to use in vehicles. For example, the current carriers and battery modules may be used to power domestic or commercial appliances.

[0065] In some embodiments, a battery management system design implemented with multiple battery strings for an electric vehicle is disclosed. In this implementation, there is one string control unit for each battery string and multiple module monitoring boards for module voltages and temperature measurements. A single battery pack controller is used to simplify the interaction of other controllers in the vehicle with the multiple strings. Each battery string is also coupled to a current sensor and a set of contactors.

[0066] FIG. 1 depicts a block diagram of an example electric vehicle drive system 10 including a battery management system 16 as described herein. The electric vehicle drive system 10 includes the battery or voltage source 11 , an inverter 12 coupled to the battery 1 1, a current controller 13, a motor 14, and load 15, and the battery management system 16. The battery 11 can be a single phase direct current (DC) source. In some embodiments, the battery 11 can be a rechargeable electric vehicle battery or traction battery used to power the propulsion of an electric vehicle including the drive system 10. Although the battery 11 is illustrated as a single element in FIG. 1, the battery 1 1 depicted in FIG. 1 is only representational, and further details of the battery 11 are discussed below in connection with FIG. 2.

[0067] The inverter 12 includes power inputs which are connected to conductors of the battery 11 to receive, for example, DC power, single-phase electrical current, or multiphase electrical current. Additionally, the inverter 12 includes an input which is coupled to an output of the current controller 13, described further below. The inverter 12 also includes three outputs representing three phases with currents that can be separated by 12 electrical degrees, with each phase provided on a conductor coupled to the motor 14. It should be noted that in other embodiments inverter 12 may produce greater or fewer than three phases.

[0068] The motor 14 is fed from voltage source inverter 12 controlled by the current controller 13. The inputs of the motor 14 are coupled to respective windings distributed about a stator. The motor 14 can be coupled to a mechanical output, for example a mechanical coupling between the motor 14 and mechanical load 15. Mechanical load 15 may represent one or more wheels of the electric vehicle.

[0069] Controller 13 can be used to generate gate signals for the inverter 12. Accordingly, control of vehicle speed is performed by regulating the voltage or the flow of current from the inverter 12 through the stator of the motor 14. There are many control schemes that can be used in the electric vehicle drive system 10 including current control, voltage control, and direct torque control. Selection of the characteristics of inverter 12 and selection of the control technique of the controller 13 can determine efficacy of the drive system 10.

[0070] The battery management system 16 can receive data from the battery 11 and generate control signals to manage the battery 11. Further details of the battery management system 16 are discussed in connection with FIGS. 2-3 below.

[0071] Although not illustrated, the electric vehicle drive system 10 can include one or more position sensors for determining position of the rotor of the motor 14 and providing this information to the controller 13. For example, the motor 14 can include a signal output that can transmit a position of a rotor assembly of the motor 14 with respect to the stator assembly motor 14. The position sensor can be, for example, a Hall-effect sensor, potentiometer, linear variable differential transformer, optical encoder, or position resolver. In other embodiments, the saliency exhibited by the motor 14 can also allow for sensorless control applications. Although not illustrated, the electric vehicle drive system 10 can include one or more current sensors for determining phase currents of the stator windings and providing this information to the controller 13. The current sensor can be, for example, a Hall-effect current sensor, a sense resistor connected to an amplifier, or a current clamp.

[0072] It should be appreciated that while the motor 14 is depicted as an electrical machine that can receive electrical power to produce mechanical power, it can also be used such that it receives mechanical power and thereby converts that to electrical power. In such a configuration, the inverter 12 can be utilized to excite the winding using a proper control and thereafter extract electrical power from the motor 14 while the motor 14 is receiving mechanical power.

[0073] FIG. 2 is a block diagram of an example voltage source according to one embodiment. The voltage source 11 can include a plurality of battery strings 26a, 26b, . . . 26n, . . . , individually or collectively referred to herein as the battery string(s) 26, and a plurality of current sensors 28a, 28b, . . . , 28n, . . . , individually or collectively referred to herein as the current sensor(s) 28. The battery strings 26 can be individually connected to or disconnected from a positive or high power bus 20 and a negative or low power bus 25 through a plurality of switches 21a, 21b, . . . , 2 In, . . . , and 22a, 22b, . . . , 22n, . . . , individually or collectively called the switches 21 and 22. The switches 21 and 22 can be controlled by control signals from a battery management system 16. The battery management system 16 can receive, among others, voltages, V_a, V_b, . . . , V_n, . . . , which are output voltages across the respective battery strings 26a, 26b, . . . , 26n, . . . , determined using, for example a plurality of sensors (not shown). The battery management system 16 can also receive currents, l a, l b, . . . , I n, . . . , which are currents from the respective battery strings 26a, 26b, . . . , 26n, . . . , measured by the respective current sensors 28a, 28b, . . . , 28n, . . . . The battery management system 16 also can receive temperature measurements, temp a, temp b, . . . , temp n, . . . , which are one or more of temperature measurements from the respective battery strings 26a, 26b, . . . 26n, . . . . , measured by one or more temperature sensors (not shown) accompanying the battery strings. Based at least in part on the voltages, V_a, V_b, . . . , V_n, . . . , currents, l a, l b, . . . , I n, . . . , and/or temperatures, temp a, temp b, . . . , temp n, of the respective battery strings 26, the battery management system 16 can generate control signals 24a, 24b, . . . , 24n, . . . , individually or collectively referred to herein as the control signal(s) 24, for controlling the respective switches 21 and 22. Further details of the battery management system 16 are discussed below in connection with FIGS. 3.

[0074] The battery strings 26 can include a plurality of modules, each of which in turn can include a plurality of cells. Within each battery string 26, the constituent modules and cells can be connected in series as symbolically depicted in FIG. 2. In some embodiments, the voltage source 11 can include six battery strings 26 that can be connected to or disconnected from the power buses 20, 25. The battery strings 26 can be implemented with various different types of rechargeable batteries made of various materials, such as lead acid, nickel cadmium, lithium ion, or other suitable materials. In some embodiments, each of the battery strings can output about 375V-400V if charged about 80% or more.

[0075] The current sensors 28 can be connected in series with the respective battery strings 26 between the high and low power buses 20, 25. As shown in FIG. 2 the current sensor 28 can be connected to the positive side of the respective battery strings 26 to measure the current discharged from the battery strings 26. In other embodiments, the current sensors 28 can be connected to the battery strings 26 otherwise to measure the current flow due to discharging of the battery strings 26.

[0076] The switches 21 and 22 can be contactors configured to connect the battery strings 26 to the power buses 20, 25 or disconnect the battery strings 26 from the power buses 20, 25 in response to the respective control signals 24. The switches 21 can be implemented with any suitable contactors capable of handling the level of current and voltage as needed in connection with, for example, the battery strings 26, the power buses 20, 25, and the load 15 (FIG. 1) within the electric vehicle drive system 10 (FIG. 1). In some embodiments the switches 21 and 22 can be implemented with mechanical contactors with solenoid inside. In some embodiments, the switches 21 can be powered by one or more drivers in the battery management system 16. Although in the illustrated example in FIG. 2, the switches 21 (e.g., 2 In) and the switches 22 (e.g., 22n) are controlled by the same respective control signals 24 (e.g., 24n), in other embodiments, the switches 21 (e.g., 21n) can be controlled by respective positive bus connect control signals while the switches 22 (e.g., 22n) can be controlled by respective negative bus connect control signals. [0077] The battery management system 16 can include a plurality of passive and/or active circuit elements, signal processing components, such as analog-to-digital converters (ADCs), amplifiers, buffers, drivers, regulators, or other suitable components. In some embodiments, the battery management system 16 can also include one or more processors to process incoming data to generate outputs, such as the control signals 24. In some embodiments, the battery management system 16 can also include one or more components for communicating and sending and receiving data within the battery management system 16 and/or with other components or circuitries in the electric vehicle. For example, the various components and circuits within the system 10, including components in the battery management system 16 can be in communication with one another using protocols or interfaces such as a CAN bus, SPI, or other suitable interfaces. And in some embodiments, the processing of incoming data can be at least in part performed by other components not in the battery management system 16 within the electric vehicle as the battery management system 16 communicates with other components.

[0078] FIG. 3 is another block diagram of example voltage source and battery management system according to one embodiment. In FIG. 3, one exemplary battery string 26n of the plurality of battery strings 26 of FIG. 2 is illustrated, and accordingly, the corresponding current sensor 28n, switches 2 In, 22n, and connect control signal 24n are illustrated. Also illustrated is a fuse 3 In corresponding to the battery string 26n, and although not illustrated, the battery strings 26a, 26b, . . . , 26n, . . . in FIG. 2 may each also have corresponding fuse 31a, 31b, . . . , 3 In, . . . . The battery string 26n includes a plurality of battery modules 38n_l, 38n_2, . . . , 38n_k (individually or collectively referred to herein as 38n for the battery string 26n), each sending battery module telemetry data to respective module monitoring boards 36n_l, 36n_2, . . . , 36n_k (individually or collectively referred to herein as 36n for the battery string 26n) of the battery management system 16. The battery management system 16 includes a string control unit 34n for the battery string 26n in communication with the battery modules 38n_l, 38n_2, . . . , 38n_k for the battery string 26n. The battery management system 16 can include an analog -to-digital converter (ADC) 32n for processing analog data from the battery string 26n. In some embodiments, the ADC 32n can be internal to the string control unit 34n, and in other embodiments, the ADC 32n can be separate from the string control unit 34n. Although not illustrated, the battery management system 16 also may include respective string control units 34a, 34b, . . . , 34n, . . . and respective ADCs 32a, 32b, . . . , 32n, . . . for the plurality of battery strings 26a, 26b, . . . , 26n, . . . illustrated in FIG. 2. The battery management system 16 also includes a battery pack controller 31, which controls a switch driver 35 and is in communication with the plurality of string control units 34.

[0079] In the illustrated embodiment, the nth battery string 26n has k number of battery modules 38n and k number of module monitoring boards 36n. In some embodiments, one battery string 26 may include, for example 6 battery modules 38 in series. In some embodiments, one battery module 38 may include, for example, 16 battery bricks in series, and a battery brick may include 13 battery cells in parallel. Also, in some embodiments the voltage source 11 (FIG. 1) of the electric vehicle drive system 10 (FIG. 1) can include 1 battery pack, which includes, for example 6 battery strings 26. A battery cell can be, for example, a Li-ion cell, and the battery pack for the electric vehicle drive system 10 can provide power greater than, for example 500 kW.

[0080] Each of the battery modules 38 may be assembled with an interface, such as a board or plane (not shown), that is configured to gather various battery module telemetry data such as voltage, current, charge, temperature, etc. to be communicated to the module monitoring boards 36. In the illustrated embodiment, the module monitoring boards 36n_l, 36n_2, . . . , 36n_k communicate with the string control unit 34n using a communication protocol, such as isoSPI. In the illustrated embodiment, the module monitoring boards 36n can gather, for example, temperature and voltage data of the respective modules 38n and communicate them to the string control unit 34n. Also in some embodiments, analog measurement data from the battery modules 38n and the battery string 26n can be processed with the ADC 32n for further digital processes at the string control unit 34n and the battery pack controller 31, for example. In some embodiments, the module monitoring boards 36n can be individually and directly in communication with the string control unit 34n, and in other embodiments, the module monitoring boards 36n can be collectively and/or indirectly in communication with the string control unit 34n through a communication bus or in a daisy chained configuration.

[0081] The string control unit 34n can be a processor configured to monitor status of the battery modules 38n and the battery string 26n, test and monitor isolation of the battery string 26n, manage temperature of the battery modules 38n and the battery string 26n, execute battery management algorithms, and generate the control signal 24n for controlling one or both of the switches 21n and 22n of the battery string 26n. Similarly, the respective string control units 34a, 34b, . . . , 34n, . . . for the battery strings 26a, 26b, . . . , 26n, . . . illustrated in FIG. 2 can perform the same functions for the respective battery strings 26 so that the battery management system 16 as a whole outputs the control signals 24a, 24b, . . . , 24n, . . . from the respective string control units 34a, 34b, . . . , 34n, . . . to the corresponding switches 21a, 21b, . . . , 2 In, . . . , and 22a, 22b, . . . , 22n, . . . . In the illustrated embodiment, the string control unit 34n can also be in communication with the current sensor 28n and receive, for example, the current reading I n of the battery string 26n. Also, the string control unit 34n can be coupled to the fuse 3 In to receive, for example, an indication of a tripped circuit or a blown fuse.

[0082] The battery pack controller 31 in the illustrated embodiment can be in communication with the plurality of string control units 34a, 34b, . . . , 34n, . . . . In some embodiments, various data from the one or more of the battery strings (e.g., string a, string b, . . . , string n, . . . ) can be communicated using CAN buses and the battery management system 16 may include a plurality of CAN bus transceivers (not shown). The battery pack controller 31 is also coupled to the switch driver 35, which can provide power to the switches 21 and 22 (e.g. contactors) of the battery strings 26, and the battery pack controller 31 can be in further communication with other devices, components, or modules of the electric vehicle. In certain instances, the battery pack controller 31 can communicate to the switch driver 35 to cut power and disconnect all the switches 21 and 22. For example, when the battery pack controller 16 may be configured to disconnect all the switches 21 and 22 when it receives a signal that indicates an air bag is deployed. Also, in certain instances, the string control unit 34n may receive high temperature data from one of the modules 38n and send a warning signal to the battery pack controller 31. In such instances, the built-in redundancy of the multi-string battery structure and the battery management system allows disconnecting the potentially troubling battery string without affirmatively determining whether disconnecting the battery string is required.

[0083] It can be advantageous to implement a battery management system for an electric vehicle as disclosed herein. With conventional thinking, the parallel system looks like it will cost n times the cost of a conventional system, where is n is the number of parallel strings. However, in most safety critical Lithium battery system, redundancy is typically needed anyway, to improve false positive or negative trips. Also, the battery pack split into multiple battery strings allows use of lower current contactors, reducing cost while increasing modularity. In traditional systems with lithium batteries, if a voltage sensor fails, most battery management systems are forced to open switches or contactors of the whole pack because of a risk of overcharge which can lead to a fire or explosion. Because of this, traditional systems include a redundant voltage measurement. The voltage measurement could be another board such as an additional module monitoring board, or a Hardware Overvoltage device on the cell level.

[0084] With a multi-string system, in case of a broken voltage sensor or current sensor or temperature sensor, one string can be independently taken out of the pack and the battery pack still delivers power with the remaining strings. With a battery management system implemented as disclosed herein, added voltage redundancy may not be necessary for reliability because the level of redundancy is already built into the multi-string management system. If a voltage sensor fails, a cautious approach may be taken, removing the string, and the vehicle will still have power for the application from the remaining strings.

[0085] By avoiding redundant temperature, voltage and current sensors in a multi-string battery pack, costs can be kept low while reliability and safety can be increased. The control unit can be programmed to be safer than traditional systems, with the ability to independently open and close contactors compared to traditional battery management systems, because other strings provide redundant backup.

[0086] The multi-string battery structure and battery management system disclosed herein can also be advantageous in providing continuous power to the electric vehicle as the distributed currents in the multi-string structure and the battery management system allow increased continuous power capability of the battery pack. In some instances continuous current draw of over 1 kA can be implemented using the disclosed system. Furthermore, because the multiple battery strings distribute the total output current over multiple branches, the disclosed battery structure and battery management system allows the system to be implemented with components such as fuses, current sensors, and contactors that are cost- and size-effective as the current in one battery string is lower than is present in a non-multi-string system, and thus the individual components in a string need not carry or measure as high a current. For example, with six separate strings each handling 300 A maximum output can produce a total maximum output of 1.8 kA. Although this multi-string system may use six sets of contactors, fuses, and current measurement devices, the total cost of six sets of these devices each suitable for 300 A operation can be lower total cost as well as higher accuracy operation than a single set suitable for 1.8 kA operation. Also, the built in redundancy, among other features, of the system disclosed herein allows high reliability as faulty strings can be disconnected and removed from operation while the remaining strings can continue to provide power to the electric vehicle. The multi-string battery structure and the battery management system also allow modularity, adaptability, and scalability depending on the size and type of the vehicle and the level of power needed for the vehicle's intended use. The battery management system disclose herein provides the benefits of having multiple battery strings while effectively and efficiently managing a great number of contactors and fuses.

[0087] FIG. 4 is a diagrammatic illustration of an exemplary electric vehicle 100. Electric vehicle 100 may propelled by one or more electric motors 110. Electric motor 110 may be coupled to one or more wheels 120 through a drivetrain (not shown in FIG. 4). Electric vehicle 100 may include a frame 130 (also known as an underbody or chassis). Frame 130 may be a supporting structure of electric vehicle 100 to which other components may be attached or mounted, such as, for example, a battery pack 140.

[0088] Electric vehicle 100 may further include structural rails 150, rear crumple zone 160, front crumple zone 170, and lateral crumple zone 180. Battery pack 140 may have a compact "footprint" and be disposed such that it may be at least partially enclosed by frame 130. Battery pack 140 may be positioned at a predefined distance from structural rails 150. In some embodiments, battery pack 140 may be positioned such that frame 130, structural rails 150, rear crumple zone 160, front crumple zone 170, and lateral crumple zone 180 protect battery pack 140 from forces or impacts exerted from outside of electric vehicle 100, for example, in a collision. In some embodiments, battery pack 140 may be disposed in frame 130 to help improve directional stability (e.g., yaw acceleration). For example, battery pack 140 may be disposed in frame 130 such that a center of gravity of electric vehicle 100 may be in front of the center of the wheelbase (e.g., it may be bounded by a plurality of wheels 120).

[0089] FIG. 5 A is a diagrammatic illustration of exemplary battery pack 140. Imaginary x-, y-, and z-axes are depicted on battery pack 140. Battery pack 140 may be of any size and dimensions. For example, battery pack 140 may be approximately 1000 mm wide (along x-axis), 1798 mm long (along y-axis), and 152 mm high (along z-axis).

[0090] In some embodiments, battery pack 140 may be modular and/or subdivided into smaller functional units. For example, battery pack 140 may include a plurality of battery modules 210. In one example, battery pack 140 may include thirty-six battery modules 210. At least some of battery modules 210 may be electrically connected in a series forming a string 212, and two or more strings 212 may be electrically connected in parallel. In various embodiments, modular battery configurations may be advantageous, for example, by allowing the battery pack 140 to continue operating despite the failure or malfunction of one or more strings 212, such as by disconnecting the malfunctioning strings 212. In this exemplary configuration, if one of strings 212 fails, others of strings 212 may not be affected.

[0091] FIG. 5B depicts exemplary battery pack 140 in an exemplary enclosure 200. Enclosure 200 may include a tray 260. Enclosure 200 may further include a cover (not illustrated).

[0092] Tray 260 may include a positive bus bar 220 and a negative bus bar 230. Negative bus bar 230 and positive bus bar 220 may be disposed along opposite edges of tray 260, or may be disposed to have a predefined separation between negative bus bar 230 and positive bus bar 220.

[0093] Positive bus bar 220 may be electrically coupled to a positive portion of a power connector of each battery module 210. Negative bus bar 230 may be electrically coupled to a negative portion of a power connector of each battery module 210. Positive bus bar 220 may be electrically coupled to positive terminals 225 of enclosure 200. Negative bus bar 230 may be electrically coupled to negative terminals 235 of enclosure 200. When used in electric vehicle 100, bus bars 220 and 230 may be disposed within structural rails 150.

[0094] In electric vehicle 100, battery pack 140 may supply electricity to power one or more electric motors 1 10, for example, through an inverter. The inverter may change direct current (DC) from battery pack 140 to alternating current (AC), as may be required for electric motors 110, according to some embodiments.

[0095] In some embodiments, battery pack 140 may be liquid cooled. Liquid cooling may be desirable for various battery pack configurations by providing efficient heat transfer in relatively compact battery configurations, so as to provide reliable temperature regulation and maintain battery cells within a desired range of operating temperatures. In liquid cooled embodiments, coolant may enter the battery pack 140 at a coolant inlet 240 and may leave at a coolant outlet 250.

[0096] FIGS. 6A and 6B illustrate exemplary coolant flows and the exemplary operation of an exemplary coolant system and an exemplary coolant sub-system that may be used in conjunction with battery pack 140. FIG. 6B is an enlarged module 210 of the pack 140 depicted in FIG. 6 A. As depicted in FIGS. 6A and 6B, an exemplary coolant system may include an ingress 310 and an egress 320. For example, coolant may be pumped into battery pack 140 at ingress 310 and pumped out of battery pack 140 at egress 320. For example, coolant may be routed in parallel to each of battery modules 210 in battery pack 140. The resulting pressure gradient within battery pack 140 may provide sufficient circulation of coolant to minimize a temperature gradient within battery pack 140 (e.g., a temperature gradient within one of battery modules 210, a temperature gradient between battery modules 210, and/or a temperature gradient between two or more of strings 212 shown in FIG. 5A).

[0097] Within battery pack 140, the coolant system may circulate the coolant, for example, to battery modules 210 (e.g., reference numeral 330 indicates the circulation). Coolant may include at least one of the following: synthetic oil, for example, poly-alpha- olefin (or poly-a-olefin, also abbreviated as PAO) oil, ethylene glycol and water, liquid dielectric cooling based on phase change, and the like.

[0098] One or more additional pumps (not shown) may be used to maintain a roughly constant pressure between multiple battery modules 210 connected in series (e.g., in string 212 in FIG. 5A) and between such strings.

[0099] The coolant sub-system may circulate coolant within battery modules 210 (e.g., the circulation indicated by reference numeral 340). In some embodiments, the coolant may enter each battery module 210 through an interface 350. The coolant may flow through battery module 210. Interface 350 may be oriented to channel coolant into battery module 210 along the y-axis. Coolant may then be driven by pressure within the coolant system to flow out of battery module 210 through one or more channels 350b oriented along the x-axis. Coolant may then be collected at the two (opposite) side surfaces 360 A and 360B of the module. Side surfaces 360A and 360B may be normal to the x-axis. In some embodiments, the coolant and sub-coolant systems may be used to maintain a substantially uniform and/or constant temperature within battery pack 140.

[0100] As discussed, exemplary battery pack 140 may include multiple battery modules 210. FIGS. 7A and 7B illustrate exemplary arrangements and couplings between two battery modules 210: 210i and 210₂. FIG. 7A depicts exemplary battery modules 210i and 210₂ separated but aligned for coupling. For example, battery modules 210₁ and 210₂ may be positioned as shown in FIG. 7A and then moved together until coupled as shown in the example in FIG. 7B. Generally, female connectors 41 Op on one of battery modules 21 Oi and 210₂ may receive and engage male connectors 410M on the other of battery modules 210₂ and 21 Oi, respectively. One or more female-male connector pairings may be included on each of battery modules 21 Oi and 210₂.

[0101] As shown in the example in FIG. 7A, a left side of battery modules 210i and 210₂ may have male connectors 410M, and a right side of battery modules 210i and 210₂ may have female connectors 41 Op. Alternatively, a mix of male connectors 410M and female connectors 41 Op may be used. Each female connector 41 Op may include an (elastomer) o-ring or other seal. Male connectors 410M and female connectors 41 Op may act only as connection points or may also be power connectors, coolant ports, etc.

[0102] FIG. 7B depicts a cross-sectional view of exemplary battery modules 21 Oi and 210₂ coupled together. For example, male connectors 410M and female connectors 41 Op combine to form coupled connectors 410c. As discussed, male connectors 410M and female connectors 41 Op may be power connectors or coolant ports of battery modules 210. For example, one of male connectors 410_M may be a coolant output port of battery module 210₂, and one of female connectors 41 Op may be a female coolant output port of battery module 21 Oi. Thus, the male and female ports may be coupled, and the internal cooling channels of the battery modules may be connected, for example, forming the cooling system schematically illustrated in FIGS. 6A and 6B. Similarly, multiple battery modules 210 may be electrically connected via a male connector 410M and a female connector 41 Op when coupled together.

[0103] FIG. 8 is a diagrammatic illustration of an exemplary battery module 210. Battery module 210 may include two half modules 510i and 510₂, coolant input port 520, coolant output port 530, communications and low power connector 540, and/or main power connector 550. Each of half modules 510i and 510₂ may also include an enclosure 560 for housing battery cells therein. Enclosure 560 may further include a plate 570 (discussed in greater detail with respect to FIG. 9).

[0104] Continuing with FIG. 8, half modules 510i and 510₂ of battery module 210 may further include a current carrier 580 (discussed in more detail with reference to FIGS. 11 and 12-18), and may include one or more staking features 590, for example, a plastic stake, to hold current carrier 580 in battery module 210. Half modules 510i and 510₂ may be the same or may be different (e.g., half modules 510i and 510₂ may be mirror images of each other in some embodiments). Coolant may be provided to battery module 210 at main coolant input port 520, circulated within battery module 210, and received at main coolant output port 530.

[0105] Communications and low power connector 540 may provide low power, for example, to electronics for data acquisition and/or control, and sensors. In some embodiments, communications and low power connector 540 may be at least partially electrically coupled to current carrier 580, for example, through electronics for data acquisition and/or control. Each of coolant input port 520, coolant output port 530, communications and low power connector 540, and main power connector 550 may serve as male connectors 410M and female connectors 41 Op.

[0106] FIG. 9 is a diagrammatic illustration of battery module 210, with the battery cells and current carrier 580 removed from one of the half modules for illustrative purposes. As described, battery module 210 may include two half modules 510i and 510₂, main power connector 550, main coolant output port 530, main coolant input port 520, and communications and low power connector 540. Further, each of the half modules 510i and 510₂ may include enclosure 560.

[0107] Enclosure 560 may be made using one or more plastics having sufficiently low thermal conductivities. Respective enclosures 560 of each of the half modules may be coupled with one another other to form the housing for battery module 210. Enclosure 560 may additionally include a cover (not illustrated). Each enclosure 560 may further include plate 570 (e.g., a bracket). Plate 570 may include structures for securing the battery cells within enclosure 560 and maintaining the distance between battery cells.

[0108] FIG. 10 is a diagrammatic illustration of an exemplary battery module 210, with current carrier 580 removed from one of the half modules for illustrative purposes. Each half module may include at least one battery cell 710. Main power connector 550 may provide power from battery cells 710 to outside of battery module 210.

[0109] FIG. 11 is a diagrammatic illustration of half module 510 without enclosure 560. Half module 510 may include a coolant intake 840 and a coolant egress 850, which may allow for use of the coolant sub-system discussed with reference to FIGS. 6A and 6B. Half module 510 may further include an electrical interface 830, which may be electrically connected to current carrier 580. Electrical interface 830 may be coupled to communications and low power connector 540. Half module 510 may also include a plurality of battery cells 710. Battery cells 710 may have a cylindrical body, and may be disposed between current carrier 580 and blast plate 810 in space 820, such that an exterior side of each of battery cells 710 may not be in contact with the exterior sides of other (e.g., adjacent) battery cells 710.

[0110] FIG. 12 depicts an exemplary battery cell 710. In some embodiments, battery cell 710 may be a lithium ion (li-ion) battery or any other type of battery. For example, battery cell 710 may be an 18650 type li-ion battery that may have a cylindrical shape with an approximate diameter of 18.6 mm and approximate length of 65.2 mm. Other rechargeable battery form factors and chemistries may additionally or alternatively be used. In various embodiments, battery cell 710 may include a first end 910, a can 920 (e.g., the cylindrical body), and a second end 940. Both an anode terminal 970 and a cathode terminal 980 may be disposed on first end 910. Anode terminal 970 may be a negative terminal of battery cell 710, and cathode terminal 980 may be a positive terminal of battery cell 710. Anode terminal 970 and cathode terminal 980 may be electrically isolated from each other by an insulator or dielectric.

[0111] Battery cell 710 may also include scoring on second end 940 to promote rupturing so as to effect venting in the event of over pressure. In various embodiments, all battery cells 710 may be oriented to allow venting into the blast plate 810 for both half modules.

[0112] Within half module 510, battery cells 710 may be disposed such that the cylindrical body of the battery cell may be parallel to the imaginary x-axis ("x-axis cell orientation"). According to some embodiments, x-axis cell orientation may offer additional safety and efficiency benefits. For example, in the event of a defect in half module 510 or battery module 210, the battery cells may be vented along the x-axis. Further, according to some embodiments, x-axis cell orientation may also be advantageous for efficient electrical and fluidic routing to each of battery module 210 in battery pack 140.

[0113] In addition, x-axis cell orientation may also be advantageous, according to some embodiments, for routing coolant (cooling fluid) in parallel to each of battery modules 210 in battery pack 140. Using the coolant systems described with reference to FIGS. 6 A and 6B, as illustrated in FIG. 11, coolant may enter half module 510 through coolant intake 840 and may exit through coolant egress 850. Coolant intake 840 and coolant egress 850 may each be male or female fluid fittings.

[0114] With reference to FIGS. 6A and 6B, channels 350B may be formed within the spaces between the cylindrical bodies of adjacent battery cells 710. Channels 350B may be metal tubes, but may also be spaces between the cylindrical bodies of battery cells 710, which may allow for higher battery cell density within battery module 210, in some embodiments by up to 15% or more. Channels 350B may or may not occupy the entire space between adjacent battery cells 710. Air pockets, which may reduce the weight of half module 510, may also be formed in the space between adjacent battery cells 710.

[0115] Such an exemplary parallel cooling system may be used to maintain the temperature of battery cells 710 within battery module 210 (and across battery back 140) at an approximately uniform level. According to some embodiments, the direct current internal resistance (DCIR) of each battery cell may vary with temperature; therefore, keeping each battery cell in battery pack 140 at a substantially uniform and predefined temperature range may allow each battery cell to have substantially the same DCIR. Voltage across each battery cell may be reduced as a function of its respective DCIR, and therefore each battery cell 710 in battery pack 140 may experience substantially the same loss in voltage. In this exemplary way, according to some embodiments, each battery cell 710 in battery pack 140 may be maintained at approximately the same capacity, and imbalances between battery cells 710 in battery pack 140 may be reduced and/or minimized.

[0116] Returning to FIG. 10, according to some embodiments, each of half modules 510i and 510₂ may include the same number of battery cells 710. In various embodiments, each half module may include a number of battery cells 710 in the range of 20, 50, 100, 200, or more. For example, each half module may include one hundred-four battery cells 710. Battery cells 710 may be electrically connected via current carrier 580. For example, thirteen of battery cells 710 may form a group and may be electrically connected in parallel, with a total of eight of such groups of thirteen battery cells 710 electrically connected in series. This exemplary configuration may be referred to as "8S13P" (8 series, 13 parallel). Other combinations and permutations of battery cells 710 electrically coupled in series and/or parallel may be used. Exemplary grouping of the battery cells is discussed in greater detail in connection with a current carrier that provides electrical connection among the battery cells.

[0117] With reference to FIG. 11, in various embodiments, battery half modules 510i and 510₂ may include a current carrier 580 configured to connect the terminals of a plurality of electrochemical battery cells. For example, the current carrier 580 may include a plurality of wires, a flex circuit, or the like. Various embodiments may include flex circuits as current carriers 580. A flex circuit may provide various advantages, such as flexibility, durability, and ease of manufacture (e.g., a flex circuit designed for a particular configuration of battery cells may be placed on top of the configured battery cells and secured in place, avoiding the need for additional wiring or other complex electrical connections. Without limiting the scope of current carriers that may be included with the battery systems described herein, an example embodiment of a current carrier will now be described.

[0118] FIG. 13 is a diagrammatic illustration of an exemplary current carrier 580. In some embodiments, current carrier 580 may be generally planar, and may be of any size and dimensions depending on the size and dimensions of half module 510. Current carrier 580 may be in electrical connection with battery cells 710 and may conduct current between the battery cells through, e.g., a positive contact 1010, a negative contact 1020, and a fuse 1030. For example, positive contact 1010 may be in electrical contact with cathode terminal 980 and negative contact 1020 may be in electrical contact with anode terminal 970. Current carrier 580 may be electrically coupled to electrical interface 830, which may transport signals from current carrier 580, for example from a signal plane of current carrier 580. Electrical interface 830 may include an electrical connector (not shown). Current carrier 580 may also provide electrical connectivity to outside of battery module 210, for example, through main power connector 550.

[0119] FIG. 14 is a second diagrammatic illustration of an exemplary current carrier 580. As shown in FIG. 14, main power connector 550 and low power connector 540 may be coupled to current carrier 580. According to some embodiments, current carrier 580 may also include a telemetry board connector 1 110, medium holes 1120, and small holes 1130.

[0120] Telemetry board connector 1 110 may communicatively couple a telemetry board (not shown) with current carrier 580 and communications and low power connector 540. For example, the telemetry board may include electronics for data acquisition and/or control, and sensors, such as for battery module telemetry.

[0121] Medium holes 1120 and small holes 1130 may be used to affix current carrier 580 to plate 570. For example, current carrier 580 may be hot staked to a plate 570 through small holes 1130 or medium holes 1120, or small holes 1130 or medium holes 1120 may be coupled to staking features 590. Alternatively or in addition, coolant may be circulated through medium holes 1120 and/or small holes 1 130.

[0122] Current carrier 580 may include a printed circuit board and a flexible printed circuit. For example, the printed circuit board may variously include at least one of copper, FR-2 (phenolic cotton paper), FR-3 (cotton paper and epoxy), FR-4 (woven glass and epoxy), FR-5 (woven glass and epoxy), FR-6 (matte glass and polyester), G-10 (woven glass and epoxy), CEM-1 (cotton paper and epoxy), CEM-2 (cotton paper and epoxy), CEM-3 (non-woven glass and epoxy), CEM-4 (woven glass and epoxy), and CEM-5 (woven glass and polyester). By way of further non-limiting example, the flexible printed circuit may include at least one of copper foil and a flexible polymer film, such as polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), polyetherimide (PEI), along with various fluoropolymers (FEP), and copolymers. [0123] As shown in FIG. 14, current carrier 580 may also be composed of multiple sections in order to implement flexible configuration of electrical connection of battery cells 710.

[0124] FIGS. 15 is a top view and FIG. 16 is a side view of the exemplary current carrier 580 of FIG. 14. Current carrier 580 may include multiple layers, which may be sandwiched between dielectric isolation layers (e.g., made of polyimide). According to some embodiments, current carrier 580 may provide electrical connectivity between and among battery cells 710. As noted, current carrier 580 may be electrically connected to a plurality of battery cells 710, and may connect battery cells 710 in series or in parallel.

[0125] FIG. 17 is an enlarged diagrammatic illustration of a portion of an exemplary current carrier 580. FIG. 17 depicts exemplary positive contact 1010, negative contact 1020, and fuse 1030. Current carrier 580 may include a plurality of each of positive contacts 1010, negative contacts 1020, and fuses 1030. Positive contact 1010 and negative contact 1020 may be separate. The position and shape of positive contact 1010 and negative contact 1020 may vary based on the shape of battery cell 710. In some embodiments, positive contact 1010 may be welded (e.g., laser welded) to a cathode terminal 980 of battery cell 710, and negative contact 1020 may be welded (e.g., laser welded) to an anode terminal 970 of battery cell 710. In some embodiments, the welded connection may have on the order of 5 milli-Ohms of resistance or less. In contrast, electrically coupling the elements using ultrasonic bonding of aluminum bond wires may have on the order of 10 milli-Ohms resistance. Welding may also have lower resistance for greater power efficiency and may take less time to perform than ultrasonic wire bonding.

[0126] Current carrier 580 may be configured such that a positive contact 1010 and a negative contact 1020 may be connected to the respective cathode and anode terminals of respective battery cells 710, for example, when the first end 910 of each battery cells 710 is oriented in the same direction. Therefore, two battery cells 710 may be connected in series with each other when negative contact 1020 connected to the anode of the first battery cell is electrically connected with the positive contact 1020 connected to the cathode of the second battery. Likewise, two battery cells 710 may be connected in parallel with each other when negative contacts 1020 connected with the cells are electrically connected with each other. [0127] Accordingly, by designing the electrical connectivity of positive contacts 1010 and negative contacts 1020 on current carrier 580, battery cells 710 may be connected in series or in parallel. For example, a group of battery cells 710 may be connected in parallel via a plurality of electrically connected positive contacts 1010 of current carrier 580, and the respective plurality of electrically connected negative contacts 1020 of current carrier 580. According to some embodiments, a first group and a second group of batteries 710 may be connected in series if negative contacts 1020 of the first group are electrically connected with positive contacts 1010 of the second group. According to some embodiments, the number of battery cells in the first group and the number of battery cells in the second group may be the same or different.

[0128] Current carrier 580 may also include fuse 1030, which may be formed from part of a metal layer (e.g., copper, aluminum, etc.) of current carrier 580. In some embodiments, fuse 1030 may be formed (e.g., laser etched) in a metal layer to dimensions corresponding to a type of low-resistance resistor, and may act as a sacrificial device to provide overcurrent protection. For example, in the event of thermal runaway of one of battery cell 710 (e.g., due to an internal short circuit), the fuse may "blow," and may break the electrical connection to the battery cell 710 and electrically isolate the battery cell 710 from current carrier 580.

[0129] FIG. 18A illustrates an exploded view of an exemplary current carrier 580. Current carrier 580 may include main power connector 550, low power connector 540, and/or telemetry board connector 1110. Current carrier 580 may include a first layer 1410, a base layer 1420, which may provide dielectric isolation, and a second layer 1430. As depicted in FIG. 18B, one or more isolation layers 1440 may also be included in current carrier 580. Current carrier 580 may further include a signal plane, which in some embodiments may include signal traces and may be used to provide battery module telemetry (e.g., battery cell voltage, current, state of charge, and/or temperature from optional sensors on current carrier 580) to outside of battery module 210. Alternatively, the signal plane may be integrated into one or more layers of current carrier 580 or may be omitted. First layer 1410 and second layer 1430 may be disposed on a respective first side and second side of base layer 1420. [0130] As shown in FIGS. 18A and 18C, first layer 1410 may include multiple sections. Similarly, second layer 1430 may include multiple sections. Each section may include a group of contacts electrically connected with the anodes/cathodes of the respective battery cells 710 in a cell group. Each section may have the same number of contacts or may have a different number of contacts. The contacts within each section may be positive contacts 1010 or negative contacts 1020.

[0131] First layer 1410 and second layer 1430 may include sections of any shape or dimensions, depending on the desired positioning of battery cells 710, the desired shape and size of battery module 210, and the desired electrical connection between and among battery cells 710. First layer 1410 and second layer 1430 may be composed of metal or other conductive materials known in the art. Both first layer 1410 and second layer 1430 may also have more or fewer sections than depicted in FIGS. 18A and 18C. Second layer 1430 may have the same number of sections as first layer 1410 or may have a different number of sections.

[0132] When used in half module 510, current carrier 580 may electrically connect the plurality of battery cells 710 in half module 510. The plurality of battery cells 710 in half module 510 may be divided into groups and may be oriented such that the first end 910 of each battery cell 710 is oriented in the same direction. For example, according to some embodiments, the plurality of battery cells 710 may be divided into eight cell groups CGo to CG₇. According to some embodiments, the number of battery cells 710 in each cell group may be the same. It is also contemplated that the number of battery cells 710 in a cell group may be different than the number of battery cells 710 in another cell group. The anode terminal 970 of each of battery cell 710 within a first cell group may be electrically connected to a negative contact 1020 on first layer 1410 of current carrier 580. The cathode terminal 980 of each battery cell 710 within the first cell group may be electrically connected to a positive contact 1010 on second layer 1430. The contacts that are electrically connected together form an equipotential surface (referred to as a "node"). Battery cells 710 within each cell group are thus connected between two nodes.

[0133] For example, a first cell group CGo may be electrically coupled between node No on second layer 1430 and node Ni on first layer 1410. Thus, battery cells 710 in the cell group CGo are electrically connected in parallel. [0134] A second cell group CGi may be electrically coupled between node Ni on first layer 1410 and node N₂ on second layer 1430. Thus, battery cells 710 in the second cell group CGi are also electrically connected in parallel. Battery cells 710 of the first cell group CGo and battery cells 710 of the second cell group CGi are electrically connected in series.

[0135] Similarly, a third cell group CG₂ may be electrically coupled between node N₂ on second layer 1430 and node N3 on first layer 1410. Thus, battery cells 710 within the third cell group CG₂ may be electrically connected in parallel. Battery cells 710 of the third cell group CG₂ and the second cell group CGi are electrically connected in series.

[0136] The remaining cell groups CG₃ to CG₇ may be similarly connected. As a result, battery cells 710 within each of the eight cell groups may be electrically connected in parallel and the respective cell groups may be electrically connected in series. This exemplary circuitry is depicted in FIG. 18C.

[0137] The exemplary circuit configuration described above may increase the number of battery cells within a compact package. For example, all battery cells 710 within half module 510 may be oriented in the same direction, and still connected via this exemplary three-dimensional circuit design. With the disclosed current carrier 580, the series and parallel connections may be realized by alternating positive and negative contact groups between the multiple nodes within layers 1410 and 1430 of current carrier 580, rather than physically reorienting battery cells 710. This exemplary configuration may also result in simplified manufacturing.

[0138] With reference to FIGS. 19-23, a non-limiting example of a battery module structure will now be described. In various embodiments, battery modules such as those described herein may provide several advantages, for example, with regard to simplified assembly, reduced weight, durability, reliable operation, and/or other advantages as will be described. FIG. 19 shows an exploded view of battery module 210c according to some embodiments. As described in relation to battery module 210 in FIGS. 8 and 11, battery module 210c can include two half modules 415c and 420c. Half modules 415c and 420c can be coupled together as described in relation to FIG. 7A.

[0139] Half module 415c can be a three-dimensional mirror image of half module 420c, and vice-versa. Half modules 415c and 420c can each include half shell 430P and 43 ON, battery cells 45 OP and 45 ON, cell retainer 915P and 915N, flexible circuit 515P and 515N, and module cover 1115P and 1115N, respectively. Half shells 430P and 430N are described further in relation to enclosures 560 in FIGS. 8-10. Battery cells 450P and 450N are described further in relation to battery cells 710 in FIGS. 10-12. Cell retainers 915P and 915N are described further in relation to plate 910 in FIG. 12. Flexible circuits 51 OP and 510N are described further in relation to FIGS. 11 and 12-18. Center divider 525C is described further in relation to blast plate 810 in FIG. 11.

[0140] As shown for example in FIG. 19 battery cells 450P and 450N include eight rows of thirteen cells. The thirteen cells may be electrically connected in parallel and may be referred to as a brick. The bricks may be electrically coupled in series such that each module includes sixteen bricks that are electrically connected in series. A plurality of modules may be electrically connected to form a string. In some aspects, a sting includes six modules that are electrically connected in series. A pack may include one or more strings. In some aspects, a pack includes three to six strings that are electrically connected in parallel.

[0141] In some embodiments, battery module 210c can include telemetry module 1131. Telemetry module 1131 and similar components are described elsewhere herein in relation to electronics for data acquisition and/or control, and sensors (e.g., in FIGS. 8 and 24A-25C). Telemetry module 1131 can be communicatively coupled to flexible circuit 515P and/or 515N. Additionally or alternatively, telemetry module 1131 can be communicatively coupled to male communications and low power connector 835M and/or female communications and low power connector 835F.

[0142] FIGS. 20A-C depict assorted views of center divider 525c. Center divider 525c can include opening 8150 for coolant flow associated with main coolant output port 530 (FIG. 8) and/or opening 8250 for coolant flow associated with main coolant input port 520. Center divider 525c can include opening 1210 which may be occupied by a section of telemetry module 1131. Center divider 525c can comprise at least one of polycarbonate, polypropylene, acrylic, nylon, and acrylonitrile butadiene styrene (ABS). In exemplary embodiments, center divider 525c can comprise one or more materials having low electrical conductivity or high electrical resistance, such as a dielectric constant or relative permittivity (e.g., ε or κ) less than 15 and/or a volume resistance greater than 1010 ohm cm, and/or low thermal conductivity (e.g., less than 1 W/m °K). [0143] FIG. 21 shows half shell 430P as depicted in FIG. 19, according to some embodiments. Half shell 430P (and 430N shown in FIG. 19) can comprise at least one of polycarbonate, polypropylene, acrylic, nylon, and ABS. In exemplary embodiments, half shell 43 OP (and 43 ON) can comprise one or more materials having low electrical conductivity or high electrical resistance, such as a dielectric constant or relative permittivity (e.g., ε or κ) less than 15 and/or a volume resistance greater than 1010 ohm cm, and/or low thermal conductivity (e.g., less than 1 W/m °K).

[0144] Half shell 43 OP can include base 1310P. In some embodiments, base 131 OP and the rest of half shell 43 OP can be formed from a single mold. Base 1310P can include channel 1340P formed in half shell 430P for coolant flow associated with main coolant output port 810 (FIG. 1 1) and/or channel 1320P formed in half shell 430P coolant flow associated with main coolant input port 820. Base 1310P can include (small) holes 1330P. For example, the size and/or placement of holes 1330P in base 1310P can be optimized using computational fluid dynamics (CFD), such that each of holes 1330P experiences the same inlet pressure (e.g., in a range of 0.05 pounds per square inch (psi) - 5 psi), flow distribution of coolant through holes 1330P is even, and the same volume flow (e.g., ±0.5 L/min in a range of 0.05 L/min - 5 L/min) is maintained through each of holes 133 OP. For example, holes 133 OP may each have substantially the same diameter (e.g., ± 1 mm in a range of 0.5 mm to 5 mm). Such optimized size and/or placement of holes 1330P in base 131 OP can contribute to even cooling of batteries 450P, since each of batteries 450P experiences substantially the same volume flow of coolant.

[0145] In some embodiments, base 1310P may contribute to retention of batteries 450P in half module 410c. Base 1310P can include battery holes 1350 P about which batteries 450P are disposed (e.g., end 740 (FIG. 12) of one of battery cell 450 is positioned centered about one of battery holes 1350P). For example, at least some of batteries 450P can be fixedly attached to base 131 OP using, for example, ultraviolet (UV) light curing adhesives, also known as light curing materials (LCM). Light curing adhesives can advantageously cure in as little as a second and many formulations can advantageously bond dissimilar materials and withstand harsh temperatures. Other adhesives can be used, such as synthetic thermosetting adhesives (e.g., epoxy, polyurethane, cyanoacrylate, and acrylic polymers). [0146] Continuing with FIG. 20, half shell 430P can also include tabs 1370P and gusset 1360P. Half shell 43 ON (FIG. 19) can be a three-dimensional mirror image of half shell 43 OP. For example, half shell 43 ON can include a base having a channel for coolant flow associated with main coolant output port 810 (FIG. 8) and/or a channel for coolant flow associated with main coolant input port 820, (small) holes, battery holes, tabs, and gusset that are three-dimensional mirror images of their respective half shell 43 OP counterparts (e.g., base 1310P, channel 1340P for coolant flow associated with main coolant output port 810 (FIG. 8), channel 1320P for coolant flow associated with main coolant input port 820, (small) holes 1330P, battery holes 1350P, tabs 1370P, and gusset 1360P, respectively).

[0147] Gussets 1360P and the corresponding gussets on half shell 430N can include holes M. In some embodiments a portion of a tie rod (not shown in FIG. 21) can be in (occupy) gusset 1360P and the corresponding gusset on half shell 43 ON, and pass through each hole M of half modules 410c and 420c. For example, half modules 410c and 420c can each have two gussets on opposite sides of half shell 43 OP and 43 ON (respectively) and two tie rods, such that the two tie rods each go through two locations on a battery module 210c, providing four points of (secondary) retention. The rods can also hold two or more of battery modules 210a together when combined into string 212 (FIG. 5A), for retention and handling/moving.

[0148] Tabs 1370P and the corresponding tabs on half shell 430N can include cut out section N. Tabs 1370P and the corresponding tabs on half shell 430N can be used to laterally support two or more of battery modules 210c coupled together, for example, as in string 212 (FIG. 5A) installed in enclosure 200 (FIG. 5B). For example, a retention plate (not shown in FIG. 21) may be placed over tabs 1370P and the corresponding tabs on half shell 43 ON. A fastener (not depicted in FIG. 21) may affix the retention plate to a lateral extrusion 225 in enclosure 200 as shown in FIG. 5B. The fastener can pass through cut out section N.

[0149] Referring back to FIG. 19, cell retainers 915P and 915N can contribute to structural support of batteries 450P and 450N, respectively. For example, cell retainers 915P and 915N can keep or hold batteries 45 OP and 45 ON (respectively) in place. In some embodiments, at least some of batteries 450P and 450N can be fixedly attached to cell retainers 915P and 915N (respectively) using, for example, ultraviolet (UV) light curing adhesives or other adhesives, as described above in relation to FIG. 21. Cell retainers 915P and 915N can comprise at least one of polycarbonate, polypropylene, acrylic, and nylon, and ABS. In exemplary embodiments, cell retainers 915P and 915N can comprise one or more materials having low electrical conductivity or high electrical resistance, such as a dielectric constant or relative permittivity (e.g., ε or κ) less than 15 and/or a volume resistance greater than 1010 ohm-cm, and/or low thermal conductivity (e.g., less than 1 W/m °K). Cell retainers 915P and 915N can also contribute to structural support of flexible circuit 515P and 515N, respectively. For example, cell retainers 915P and 915N can hold flexible circuit 515P and 515N, respectively.

[0150] Flexible circuit 515P can include power bud JP and flexible circuit 515N can include power socket JN. Power bud JP and power socket JN were described in relation to main power connector 550 (FIG. 10). Power bud JP can be brazed onto flexible circuit 515P and power socket JN can be brazed onto flexible circuit 515N. Power bud JP and power socket JN can comprise any conductor, such as aluminum (alloy) and/or copper (alloy). Power bud JP and power socket JN can include conductive ring KP and KN, respectively. Conductive ring KP and KN can be placed into (attached to) hole LP and LN (respectively) of cell retainer 915P and 915N, respectively. In this way, conductive ring KP and KN can provide a larger surface area for attaching flexible circuit 515P and 515N (respectively) to cell retainer 915P and 915N, respectively. Conductive ring KP and KN can comprise any conductor, such as aluminum (alloy) and copper (alloy). In some embodiments, conductive ring KP and KN can comprise the same material as power bud JP and power socket JN, respectively.

[0151] Module cover 1115P can include male main power connector 460M, male main coolant output port 815M, male main coolant input port 825M (not shown in FIG. 19), and male communications and low power connector 835M. Module cover 1115N can include female main power connector 460F, female main coolant output port 815F, female main coolant input port 825F, and female communications and low power connector 835F. Male main power connector 460M, female main power connector 460F, male main coolant output port 815M, female main coolant output port 815F, male main coolant input port 825M, female main coolant input port 825F, male communications and low power connector 835M, female communications and low power connector 835F are described in relation to various components in FIG. 7 A. In various embodiments, half module 415c is a "positive" end of battery module 210c and half module 420c is a "negative" end of battery module 210c.

[0152] Module covers 1115P and 1115N can comprise at least one of polycarbonate, polypropylene, acrylic, nylon, and ABS. In exemplary embodiments, module covers 1115P and 1115N can comprise one or more materials having low electrical conductivity or high electrical resistance, such as a dielectric constant or relative permittivity (e.g., ε or κ) less than 15 and/or a volume resistance greater than 1010 ohm cm, and/or low thermal conductivity (e.g., less than 1 W/m °K).

[0153] FIG. 22 illustrates a cross-sectional view of battery module 210c. FIG. 22 depicts half modules 415c and 420c coupled to form battery module 210c. Center divider 525c can be disposed between half modules 415c and 420c. Half modules 415c and 420c can include base 1310P and 1310N, battery cells 450P and 450N, and module cover 1115P and 1115N, respectively.

[0154] Referring back to FIG. 19, in operation coolant can enter or flow into battery module 210c at male main coolant input port 8410M (not depicted in FIG. 19, see FIG. 7A). For example, a pump (not shown in FIG. 19) can pump coolant through battery module 210c, such that the coolant pressure is on the order of less than 5 pounds per square inch (psi), for example, about 0.7 psi. Coolant can travel through channel 1320P (FIG. 21) to center divider 525c, where the coolant (flow) can be divided between half modules 415c and 420c (e.g., such that there is a first coolant flow for half module 415c (represented as dashed lines 1415P in FIG. 22) and a second coolant flow for half module 420c (represented as dashed lines 1415N in FIG. 22)).

[0155] At base 1310P (FIG. 21) and base 1310N (not depicted in FIG. 21), the divided coolant flows through holes 133 OP and 1330N (not depicted in FIG. 21) (respectively) and toward module covers 1115P and 1115N, respectively. In half module 415c, toward module cover 1115P coolant can enter channel 1340P, flow through channel 1340N (not depicted in FIG. 21) in half module 420c, and exit battery module 210c at female main coolant output port 815F. In half module 420c, toward module cover 1115N, the coolant exits battery module 210c at female main coolant output port 815F. In various embodiments, channels 1320P, 1340P, 1320N (not depicted in FIG. 21), and 1340N are structured such that coolant flow is not "short circuited" (e.g., coolant flows from 1320P to 1340P and/or from 1320N to 1340N without passing through base 1310P and/or 13 I ON (respectively) to battery cells 450P and 450N (respectively)). By way of non-limiting example, center divider 525c can be structured such that coolant (flow) is evenly divided between half modules 415c and 420c. By way of further non-limiting example, base 1310P and/or base 1310N can be structured (e.g., size and position of holes 1330P and 1330N) such that coolant flows evenly through holes 133 OP and 133 ON. In some embodiments, the first coolant flow flows over the battery cells in a first direction within half module 415c (represented as dashed lines 1415P in FIG. 22), and the second coolant flow flows over the battery cells in a second direction within half module 420c (represented as dashed lines 1415N in FIG. 22). The first direction and the second direction can be (substantially) the opposite of each other.

[0156] According to some embodiments, the coolant can comprise any non- conductive fluid that will inhibit ionic transfer and have a high heat or thermal capacity (e.g., at least 60 J/(mol K) at 90 °C). For example, the coolant can be at least one of: synthetic oil, water and ethylene glycol (WEG), poly-alpha-olefin (or poly-a-olefin, also abbreviated as PAO) oil, liquid dielectric cooling based on phase change, and the like. By way of further non-limiting example, the coolant may be at least one of: perfluorohexane (Flutec PP1), perfluoromethylcyclohexane (Flutec PP2), Perfluoro-l ,3-dimethylcyclohexane (Flutec PP3), perfluorodecalin (Flutec PP6), perfluoromethyldecalin (Flutec PP9), trichlorofluoromethane (Freon 11), trichlorotrifluoroethane (Freon 1 13), methanol (methyl alcohol 283-403K), ethanol (ethyl alcohol 273-403K), and the like.

[0157] In various embodiments, half shell 430P and 430N can comprise an opaque (e.g., absorptive of laser light) material such as at least one of polycarbonate, polypropylene, acrylic, nylon, and ABS. In some embodiments, center divider 525c, cell retainers 915P and 915N, and module covers 11 15P and 1115N can each comprise a (different) transparent (e.g., transmissive of laser light) material such as polycarbonate, polypropylene, acrylic, nylon, and ABS. In exemplary embodiments, half shell 430P and 430N, center divider 525c, cell retainers 915P and 915N, and module covers 1115P and 1115N all comprise the same material, advantageously simplifying a laser welding schedule. [0158] Half shell 430P and 430N can be joined to center divider 525c, cell retainers 915P and 915N, and module covers 1115P and 1115N using laser welding, where two of the parts are put under pressure while a laser beam moves along a joining line. The laser beam can pass through the transparent part and be absorbed by the opaque part to generate enough heat to soften the interface between the parts creating a permanent weld. Semiconductor diode lasers having wavelengths on the order of 808 nm to 980 nm and power levels from less than 1W to 100W can be used, depending on the materials, thickness, and desired process speed. Laser welding offers the advantages of being cleaner than adhesive bonding, having no micro-nozzles to get clogged, having no liquid or fumes to affect surface finish, having no consumables, having higher throughput than other bonding methods, providing access to pieces having challenging geometries, and having a high level of process control. Other welding methods, such as ultrasonic welding, can be used.

[0159] FIG. 23 depicts a simplified flow diagram for a process 1500 for assembling battery module 210c. Although the steps comprising process 1500 are shown in a certain sequence, they may be performed in any order. Additionally, assorted combinations of the steps may be performed concurrently. In exemplary embodiments, process 1500 can produce hermetic seals at each of the fluid boundary areas of battery module 210c: half shell 430P and 430N, center divider 525c, and module covers 1115P and 1115N.

[0160] At step 1510, at least some of battery cells 450P (and 450N) can be fixedly attached to base 131 OP (and base 1310N (not depicted in FIG. 21) of half shell 43 ON), as described above in relation to FIG. 16. At step 1520, cell retainers 915P and 915N can be coupled to half shells 430P and 430N, respectively. For example, cell retainers 915P and 915N can be at least one of laser welded, ultrasonic welded, and glued (e.g., using one or more synthetic thermosetting adhesives) to half shells 430P and 430N, respectively.

[0161] At step 1530, flexible circuits 515P and 515N can be installed in half shells 430P and 430N, respectively. For example, flexible circuits 515P and 515N can be hot staked to cell retainers 915P and 915N and/or half shells 43 OP and 43 ON, respectively. At step 1540, module covers 1115P and 1115N can be bonded to half shells 43 OP and 43 ON, respectively. For example, module covers 1115P and 1115N can be at least one of laser welded, ultrasonic welded, and glued (e.g., using one or more synthetic thermosetting adhesives) to half shells 43 OP and 43 ON, respectively. [0162] At step 1550, center divider 525c can be attached to half shells 430P and 430N. For example, center divider 525c can be at least one of laser welded, ultrasonic welded, and glued (e.g., using one or more synthetic thermosetting adhesives) to half shells 43 OP and 43 ON.

[0163] Referring now to FIGS. 24A-B, modular battery pack systems will be described. As discussed above, a battery pack 140 may include one or more battery strings 212. In some embodiments, battery strings 212 may be configured to be removed, inserted, and/or replaced individually. Modular battery strings 212 as described herein may provide several advantages for electric vehicle operation. For example, a battery string 212 that is malfunctioning or otherwise in need of repair or service may be removed by a technician or owner. The removed string 212 may be replaced with a functional string 212, or the vehicle may be operated with one fewer string until the removed string 212 is repaired or replaced. Modular battery strings 212 may also be utilized for convenient battery swapping (e.g., replacing a discharged or partially discharged battery string 212 for a mostly charged or fully charged replacement string 212) to reduce time spent recharging.

[0164] The battery pack 140 depicted in FIGS. 24A-B includes six strings 140, which may be mounted in a rack or enclosure 200. The enclosure 200 may include one or more lower support elements such as a tray 260 positioned to support the strings 212 from below. The enclosure 200 may further include one or more upper support elements 265 positioned so as to prevent the strings 212 from moving upward during operation of the vehicle. Upper support elements 265 and/or tray 260 may include positioning members (not shown), such as protrusions or depressions, configured to maintain strings 212 in place and/or inhibit movement of the strings by connecting with complementary structures of strings 212. For example, the positioning members may include bolts or similar structures, with complementary structures including fasteners that may accommodate and/or secure the bolts. In some embodiments, the enclosure 200 may include one or more thermal barriers 215 including any suitable thermally insulating material, each thermal barrier 215 disposed between two of the strings 212 so as to prevent an overheating string 212 from causing neighboring strings 212 to overheat.

[0165] The strings 212 may be connected in parallel, in series, or in a combination of parallel and series connections. Each string 212 may have a positive high voltage connector (not shown) and a negative high voltage connector (not shown) for charging and for delivery of electricity to systems of the vehicle. In some embodiments, a current carrier (not shown), such as a bus bar or flexible conduit, may be located within or adjacent to one or more lower support elements such as tray 260 or upper support elements 265. For example, current carriers disposed within tray 260 may allow connections with the high voltage connectors to be made through or near a positioning member (not shown) and assisted by gravity.

[0166] Additional electrical contact with the battery strings 212 may be made through an auxiliary connector 270. The auxiliary connector 270 may permit connection between internal components (not shown) of the battery strings 270 and data or low-voltage power systems of the vehicle. For example, the auxiliary connector 270 may include a CAN connector for connection between monitoring and/or control circuitry (not shown) within the battery string 212 and a CAN bus or other wiring connector 275 of the vehicle. The auxiliary connector 270 may also include a low-voltage power supply, such as from a low voltage battery, DC-to-DC converter, or other vehicle power supply, to provide electrical power to components within the batter string 212, such as monitoring and control circuitry (e.g., string control units, battery module monitoring boards, etc.) and/or circuit disconnection elements (e.g., magnetic contactors, fusible elements, etc.). In some embodiments, the auxiliary connector 270 may include a single connector configured to transmit both power and data to and/or from internal components of the battery string 212.

[0167] The battery pack 140 may further include a cooling system, such as a liquid cooling system, to control the operating temperature of components within the battery strings 212. The cooling system may include one or more conduits (e.g., coolant supply conduit 280 and coolant return conduit 282) configured to carry liquid coolant to and from the battery strings. Conduits 280 and 282 may connect to the battery strings 212 at inlets 284 and outlets 286, which may include sealable valves, dry breaks, or other breakable liquid connections. In some embodiments, the conduits 280 and 282 may be manually connectable, such that a user can connect a supply conduit 280 to the coolant inlet 284 and connect a return conduit 282 to the coolant outlet 286 after placing a battery string 212 into an available space within the battery pack 140. The cooling system may further include elements such as a heat exchanger, pump, reservoir, or other components (not shown) in fluid communication with the conduits, to store, circulate, and cool the liquid coolant.

[0168] Individual strings 212 of the battery pack 140 may be removable, insertable, and/or replaceable. For example, in a battery pack 140 including six strings 212 as depicted in FIG. 24 A, it may be desired to remove one or more strings 212, such as for repair, replacement, service, inspection, external charging, battery swapping, or for any other purpose. The string 212 to be removed may first be disconnected by disengaging connections such as a vehicle wiring connector 275, coolant conduits 280 and 282, and high- voltage connectors (not shown). The string 212 may then be removed, such as by vertical movement, lateral movement, or a combination of vertical and lateral movement (e.g., lifting one or both ends of the string 212 and sliding the string 212 out of the enclosure 200). In some embodiments, disconnection of one or more connections may be accomplished by the action of removing the battery string 212 and not by a separate disconnection step. FIG. 24B depicts a battery pack 140 during the removal process described herein. In FIG. 24B, one string 212' is partially removed from the battery pack 140 and enclosure 200, having been disconnected from a vehicle wiring connector 275 and coolant conduits 280 and 282, and slid laterally for removal from the enclosure 200. After the string 212' has been removed, a replacement string 212 or the same string 212' may be inserted into the open space within the enclosure 200, such as by reversing the steps listed above. For example, the battery string 212 may be slid into the opening in the enclosure 200 to the position depicted in FIG. 24A. The vehicle wiring connector 275, coolant conduits 280 and 282, and high-voltage connections (not shown) may be connected to provide desired functionality of the battery string 212.

[0169] FIGS. 25A-B depict exterior views of a modular battery string 212 in accordance with an exemplary embodiment. FIG. 25A depicts an upper perspective view of a battery string 212, while FIG. 25B depicts a lower perspective view. In some embodiments, a battery string 212 may be enclosed within a protective housing 214. Housing 214 may include materials such as metals, plastics, or other materials configured to support and/or protect battery modules (not shown) within the battery string 212. The battery string 212 may further include several external connections. For example, the battery string 212 may include an auxiliary connector 270 configured to accommodate a connection to a vehicle wiring connector 275, such as a CAN bus or other data network, a low-voltage connection to power monitoring and control circuitry (not shown) within the string 212, or the like. The battery string 212 may also include a coolant inlet 284 and a coolant outlet 286, which may include sealing components such as dry breaks so as to prevent coolant within the string 212 from leaking when the string 212 is disconnected from a cooling system. Positive high-voltage connector 288 and negative high-voltage connector 290 may be located on an exterior surface of the string 212, such as on the bottom. In some embodiments, the positive and negative high- voltage connectors 288, 290 may be spaced so as to avoid accidental creation of a short circuit between the connectors 288, 290. All external battery string connections described herein (e.g., auxiliary connector 270, coolant inlet 284 and outlet 286, high-voltage connectors 288, 290, etc.) may include openings in the material of the string housing 214 and/or additional reinforcing or protecting structures such as cable entry systems, cable connectors, waterproof wiring connectors, cable harnesses, valves, dry breaks, or the like, to permit connections between internal components of the battery string 212 and external components within the vehicle. In various embodiments, any of the auxiliary connector 270, coolant inlet 284, coolant outlet 286, and high-voltage connectors 288, 290 may be located on a top surface, a bottom surface, or a side surface of the housing 214.

[0170] FIG. 25C schematically illustrates various components of a modular battery string 212 in accordance with an exemplary embodiment. A battery string 212 may include one or more battery modules 210 configured to provide high voltage power to a vehicle powertrain. The battery string 212 may further include a coolant circulation system, such as one or more coolant intake conduits 281 and coolant outlet conduits 283, and monitoring and/or control circuitry, such as a string control unit (SCU) 300. The battery string 212 may include external connections as described above, such as a positive high- voltage connector 288 and negative high-voltage connector 290 for the battery modules 210, auxiliary connector 270 for the SCU 300, a coolant inlet 284 for the coolant intake conduit 281, and a coolant outlet 286 for the coolant outlet conduit 283.

[0171] Battery modules 210 may be connected in parallel, in series, or in a combination of parallel and series connections within the battery string 212. For example, the six modules 210 depicted in FIG. 25C are connected in series so as to produce a total string voltage of up to six times the voltage of each module 210. The modules 210 may be electrically connected to the positive high-voltage connector 288 and the negative high- voltage connector 290 to deliver electrical power to vehicle systems. The modules 210 may be separable from the vehicle power circuit by one or more circuit interruption elements, such as contactors 310 and/or one or more fusible elements 312. A fusible element 312 may be included as a redundant circuit disconnection device, for example, configured to open the circuit if a contactor 310 fails. In some embodiments, a fusible element 312 may be a passive fuse, thermal cutoff, or the like. The fusible element 312 may also be a selectively blowable fuse configured to blow based on an electrical or thermal input produced in response to a detected contactor failure or other malfunction.

[0172] In various embodiments, one or more contactors 310 may be used to control current flow through the battery modules 210. Although one contactor 310 may typically be sufficient to open the circuit through the battery modules 210 and prevent current flow, two contactors 310 may be used for additional control and/or redundancy (e.g., in case of a contactor welding event or other malfunction). Contactors 310 may be located within the battery string 212 and/or outside the battery string 212, such as within the circuitry connecting the battery string 212 to the main high-voltage electrical circuit of the vehicle. Locating the contactors 310 within the battery string 212 may provide enhanced safety. For example, the contactors 310 may be normally open contactors operable only when the string is installed within the vehicle (e.g., powered by the SCU 300, which may be powered when connected to low-voltage vehicle power at the auxiliary connector 270), such that an inadvertent connection between the high-voltage connectors 288 and 290 will not cause current to flow from the battery modules 210 when the battery string 212 is not installed within a vehicle.

[0173] The battery modules 210 and other structures within the string 212 may be monitored and/or controlled by one or more module monitoring boards (MMBs) 305 and a string control unit (SCU) 300. In some embodiments, each battery module 210 may have an associated MMB 305. An MMB 305 connected to a battery module 210 may monitor any characteristic or status of the module 210. For example, the MMB 305 may monitor any one or a combination of battery module 210 temperature, coolant temperature, one or more individual battery cell temperatures, current flow into or out of the battery module 210, current flow at a location within the battery module 210, an open circuit voltage of the battery module 210, a voltage between two points within the battery module 210, a charge state of the battery module 210, a detected status such as a fault or alarm generated by a sensor within the battery module 210, or the like.

[0174] The MMBs 305 may be connected to the SCU 300 by a wired or wireless connection. In some embodiments, each MMB 305 may be connected directly to the SCU 300, or the MMBs 305 may be connected in a chain, with one or a subset of MMBs 305 connected directly to the SCU 300. The connections between the MMBs 305 and the SCU 300 may allow any of the data collected at the MMBs 305 to be transmitted from the MMB 305 to the SCU 300, such as for analysis, monitoring, or the like. The SCU 300 may include one or more processors, memory units, input/output devices, or other components for storing, analyzing, and/or transmitting data. In some embodiments, a wired connection between the SCU 300 and one or more MMBs 305 may allow the MMBs 305 to draw electrical power for operation from the SCU 300. At the SCU 300, global monitoring and/or control functions may be performed for the battery string 212. For example, the SCU 300 may monitor any characteristic or status of the battery string 212, or of any one or combination of the battery modules 210 within the string 212, such as a temperature, current, voltage, charge state, detected status such as a fault or alarm, or the like. The SCU 300 may control the operation of the battery string 212, such as by causing one or more circuit interruption elements (e.g., contactors 310) to close or open so as to allow current to flow or stop current flow between the battery modules 210 and the high voltage connectors 288 and 290.

[0175] The SCU 300 may be connected to an auxiliary connector 270 of the battery string 212 to receive power, receive data, and/or transmit data to other vehicle systems. For example, the auxiliary connector 270 may include a CAN bus connector, other data connector, a power connector, or the like. The SCU 300 may communicate any characteristic or status, or other information determined based on a characteristic or status of at least a portion of the string 212, to other systems of the vehicle through a vehicle wiring connector (not shown) connected to the battery string 212 at the auxiliary connector 270. In some embodiments, the auxiliary connector 270 may be further configured to draw current from a vehicle wiring connector (not shown) and deliver electrical power to the SCU 300, such as for operation of electrical components of the SCU 300 and/or MMBs 305. [0176] The battery string 212 may include one or more internal conduits 281, 283 for liquid coolant. As described above, coolant may enter the battery string 212 from an external conduit (not shown) at an inlet 284 and leave the battery string 212 at an outlet 286. Upon entering the battery string at the inlet 284, coolant may travel through an internal coolant intake conduit 281 to enter one of the battery modules 210. After traveling through a battery module 210, where the coolant may absorb heat from one or more components of the battery module 210 (e.g., electrochemical battery cells, internal electronic components, or the like), the coolant may travel through an internal coolant outlet conduit 283 to the coolant outlet 286, where it may return to the external cooling system. As described above, coolant leaving at the outlet 286 may be propelled by one or more pumps (not shown) to a heat exchanger, reservoir, and/or other components of the cooling system.

[0177] With reference to FIGS. 26-49, exemplary methods of assembly and manufacturing process flow for battery modules and strings of battery modules will now be described. Various embodiments of the process flow are described with respect to the steps illustrated in FIGS. 26-35, and assembly of parts along the process flow is illustrated in FIGS. 36-21B according to various embodiments.

[0178] Referring first to FIG. 36, an exploded perspective view of a battery module 1100 is illustrated to provide context for the process flow description in reference to FIGS. 26-35 that follows. The battery module 1100 can comprise a module shell 1105. The module shell 1105 can comprise a first opening 1145 for receiving a first plurality of battery cells 710 therein. Although not visible in FIG. 36, the module shell 1105 can comprise a second opening 1150 opposite the first opening 1145 for receiving a second plurality of battery cells 710 therein. An inner surface of the module shell 1105 can comprise a bottom battery cell retainer plate 1175 comprising a plurality of openings to at least partially receive the battery cells 710 therein. The module shell 1105 can further comprise in proximity to an outer edge of the module shell 1105 a circuit board receiving slot 1155 and a copper bar receiving slot 1160. A circuit board 1110 and a copper bar 1112 can be inserted into their respective receiving slots 1155, 1160. Further, the module shell 1105 can comprise one or more passageways 1165 extending entirely through the module shell 1105 from the first opening 1145 to the second opening 1150 to allow for wiring to pass through the battery module 1100, for example when a plurality of battery modules 1100 are coupled together into a battery module string. A flex circuit 1136 can be coupled to a top battery cell retainer plate 1125, and the resulting assembly can be coupled to the module shell 1105 across the first opening 1145 to fix the first plurality of battery cells 710 in place. A cover 1135 can then be coupled to the module shell 1105 to seal the first opening 1145. The cover 1135 can comprise one or more ports 1170 aligned with the passageways 1165. One or more O-rings 1140 (or other sealing mechanism as known in the art) can be placed onto each of the ports 1170. Similarly, a cell retainer plate 1125, a flexible circuit 1136, and a cover 1135 can be coupled to the module shell 1105 across the second opening 1150. The assembly and construction of the battery module 1100 will be discussed in detail below.

[0179] Referring now to FIG. 26 in conjunction with FIG. 36, a process flow for assembling a first half of the battery module 1100 can be initiated at step 3105, and then one or more pallets (or other handling devices) carrying containers of battery cells 710 can be moved from a storage area to a manufacturing line at step 3110. Data can be captured and logged at step 3120 on battery cell 710 identification information such as manufacturer, lot number, model number, serial number, and date of manufacture. Additional data can be captured and logged at step 3120 relevant to the manufacturing process such as date, time, operator name and identification number, environmental conditions (such as temperature and humidity), product for which the battery module 1100 is being built, and the like. The containers of battery cells 710 can be depalletized at step 3115, and the battery cells 710 can be removed either individually or in groups of multiple battery cells 710 from the container at step 3125.

[0180] In certain embodiments, the battery cells 710 can be removed from their containers at step 3125 using robotic equipment. As the robotic equipment grasps one or more battery cells 710, electrical contact can be made with each battery cell 710 so that the robotic equipment can perform quality control evaluation of the battery cells 710. For example, the voltage and impedance of each battery cell 710 can be checked. If the results of the quality control evaluation indicate the battery cell 710 is within acceptable parameters, the robotic equipment can transport the battery cell 710 to step 3140 to continue the process. If the battery cell 710 fails the quality control evaluation, then the battery cell 710 can be rejected at step 3130. Data obtained for each quality control evaluation, for both pass and fail situations, can be logged at step 3135. [0181] In certain embodiments, the battery cells 710 can be arranged in rows that correspond to the rows of openings in the bottom battery cell retainer plate 1175. Thus, the robotic equipment can grasp one or more of these rows of battery cells 710 to facilitate placement of the battery cells 710 into the battery module shell 1105 as described in more detail below.

[0182] In various embodiments, each battery cell 710 can have a mounting end 1205 and an electrical connection end 1206 opposite the mounting end 1205 as illustrated in FIG. 37A. At step 3140, after the battery cell 710 has passed the quality control evaluation, the robotic equipment can apply an adhesive 1215 to the mounting end 1205 of the battery cell 710 as illustrated in FIG. 37B. The adhesive 1215 can be paste, liquid, film pallets and tape so long as the adhesive is compatible with the submerged fluid or compatible with the base material that will be bonding to. In this instance, the adhesive is a one part adhesive with an accelerator (LORD 202 adhesive with LORD 4 accelerator bonding nickel plated steel to plastic (PC, PCABS... etc). The LORD 202 is an acrylic based adhesive with viscosity ranging from 8,000-32,000 cP. This adhesive bonds to unprepared metals that require little to no substrate preparation and resists dilute acids, alkalis, solvents, greases, oils and moisture, provided excellent exposure to UV exposure, salt spray and weathering. This adhesive is a no-mix adhesive that requires an accelerant (LORD Accelerator 4) to kick start the curing process. In addition, the adhesive can be used in a mix-in using LORD Accelerator 17, 18 & 19. The adhesive is placed on the cell or inside the one piece half shell and the accelerator placed on the cell or the one piece half shell based on the process chosen. These two methods are valid. Depending on the process of applying the adhesive the critical aspects of the adhesive is its bond line from .020" - .010" that gives the highest bond strength. The volume of the adhesive in this application case is 36 mg dispensed in a 4-12 dots with a 2.3 mm dot size. To optimize the dispensing time dots will be used to ensure that a uniform coverage of the adhesive is achieved during the bonding of cells and one piece half shells. The amount of accelerant is not critical as long as .002" film of accelerant is on the mating surface to activate the adhesive. Should other forms of adhesive be used, the bond line will change accordingly. Other adhesives can be used such as UV cure, humidity sensitive, and two part adhesives. For example, Loctite 3972, 4311 are candidates that one can consider using during the bonding process. [0183] In various embodiments, each battery cell 710 can have an essentially cylindrical shape with a radius ranging from Rl = 10 mm to R2 = R3 = 21.05 mm as shown in FIGS. 37A and 37B. If Rl decreases from 10mm it may affect the cooling of the cell as it will cover the cell vent and will not provide adequate cooling of the cell. Based on the design where the cells will be placed an optimum ring size shall be determined to limit the amount of glue covering or not covering the vent of the cell. For this process, an optimum ring width of 2.3 mm will generate the most consistent bond strength and adhesive coverage of the cell. In addition, instead of a ring dots ranging in all different sizes are applicable to achieve the same bond strengths and cell coverage. For this process, a dot size of 2.3 mm and a corresponding volume of 3.185 mm³ will be satisfy the design requirements of holding the cells in place. The adhesive 1215 can be applied in a ring shape as illustrated in FIG. 37B, the ring of adhesive 1215 having an outer radius of R2 and an inner radius of Rl . The volume of adhesive 1215 applied to the mounting end 1205 of the battery cell 710 can be 2.0mm³ - 5mm³ per 269.48mm² surface area to satisfy design requirements and optimum coverage of the cell and to provide the strongest bond strength.

[0184] After the adhesive 1215 has been applied to the mounting end 1205 of the battery cell 710, a quality control evaluation can be performed to verify the proper placement and amount of adhesive 1215 at step 3145. If a problem is discovered with the applied adhesive 1215, the battery cell 710 can be moved to a rework station at step 3150. Battery cells 710 with properly applied adhesive 1215 can proceed to step 3305 (see FIG. 28).

[0185] Referring now to FIG. 27 in conjunction with FIG. 36, one or more pallets (or other handling devices) carrying battery module shells 1 105 can be moved from a storage area to the manufacturing line at step 3205. The module shells 1105 can be depalletized at step 3210. Data can be captured and logged at step 3215 on module shell 1105 identification information such as manufacturer, lot number, model number, serial number, and date of manufacture. A unique identification number (e.g., a serial number) can be placed onto each of the module shells 1105 at step 3220. The number can be printed, stamped, melted, laser etched, inscribed, or otherwise permanently affixed as is known in the art to the module shell 1105. The identification number can be logged at step 3225.

[0186] At step 3230, the circuit boards 1110 and the copper bars 1112 can be moved from a storage area to the manufacturing line. Either manual or robotic equipment can be used to insert the circuit boards 11 10 into the circuit board receiving slot 1 155 and insert the copper bar 1112 into the copper bar receiving slot 1160 of the module shell 1105 at step 3235 as illustrated in FIG. 38. Identification information for the circuit board 11 10 can be captured at step 3240, such as manufacturer, date of manufacture, and serial number. This information can also be related to the identification information for the module shell 1105 with which the circuit board 1 110 is assembled. The circuit board 1 110 can provide a variety of functions such as monitoring of battery module 1100 performance, current draw on the battery module 1100, condition of the battery cells 710, and communication between and among multiple battery modules 1 100 and one or more outside intelligent agents. The copper bar 1 112 connects one side of the battery module to the next side and combines the two side voltages into one voltage. The module shell 1105 with assembled circuit board 1110 and copper bar 1 112 can then move to the next step of the exemplary process in which an accelerator 1405 can be applied at step 3245 within each of the openings in the bottom battery cell retainer plate 1175. In various embodiments, the accelerator 1405 can be applied at minimum of .002" thick film to unlimited volume so long as there is enough coverage of the bonding surface in a ring-shaped pattern within each of the openings in the bottom battery cell retainer plate 1 175 as illustrated in FIGS. 39 and 40 so that the accelerator 1405 does not cover a center portion of each opening.

[0187] The accelerator 1405 can interact with the adhesive 1215 previously applied to the mounting end 1205 of each battery cell 710 as described more fully below. The accelerator 1405 is a solvent mixture of Methylene chloride, trichloroethylene, methyl isobutyl ketone, benzoyl peroxide and methyl methacrylate. It crystalizes when sprayed on a substrate and needs to be applied to the LORD 202 in a dried state. Its viscosity is <10 cP with density of 1.22-1.28 g/cm³. At step 3250 a quality control evaluation of the applied accelerator 1405 can be performed to check that the proper amount of accelerator 1405 was applied and that the accelerator 1405 was applied in the proper pattern. Module shells 1105 that fail the quality control evaluation can be reworked at step 3255, while module shells 1105 that pass the quality control evaluation can proceed to step 3305 (see FIG. 28).

[0188] FIG. 40 illustrates a top view of the module shell 1105 after application of the accelerator 1405 according to various embodiments. Now visible in this view are a plurality of coolant holes 1505 in the bottom battery cell retainer plate 1175. The coolant holes 1505 can allow a coolant to flow through the module shell 1105 and around the battery cells 710 to remove excess heat that can be generated during charging or discharging of the battery cells 710. In various embodiments, a maskant can be applied over the coolant holes 1505 to prevent stray or excess accelerator from clogging the cooling holes 1505. The maskant can be removed prior to further processing of the module shell 1105.

[0189] Referring now to FIG. 28 in conjunction with FIG. 36, the battery cells 710 with the adhesive 1215 applied and the module shell 1105 with the accelerator 1405 applied both reach step 3305. At this step, the battery cells 710 can be inserted as illustrated in FIG. 41 through the first opening 1145 such that the mounting end 1205 of the battery cells 710 engage the openings of the bottom battery cell retainer plate 1 175 within the module shell 1105. A force can be applied to the battery cells 710 such that the adhesive 1215 contacts the accelerator 1405, thereby starting a chemical reaction between the adhesive 1215 and the accelerator 1405 that will hasten curing of the adhesive 1215. In various embodiments as illustrated in the cross-sectional view of FIG. 42, the adhesive 1215 can begin to flow due to the applied force. The flowing adhesive 1215 can fill the gap between a side wall of the battery cell 710 and the opening in the bottom battery cell retainer plate 1 175 creating a bonding layer of adhesive 1215 along the mounting end 1205 of the battery cell 710 and along the side wall of the battery cell 710 and the opening in the bottom battery cell retainer plate 1175. This continuous bonding layer can provide a strong and durable bond between the battery cell 710 and the module shell 1105 to withstand physical shock and vibration. In certain embodiments, the adhesive 1215 may not flow completely across the mounting end 1205 of the battery cell 710 as illustrated in the cross-sectional view of FIG. 42. Having a gap in the adhesive 1215 coverage can provide better and more controlled thermal management within the battery module 1 100. The force can be applied for about 1 -2 minutes to allow for proper flow and curing of the adhesive 1215, although greater or lesser times are within the scope of the present disclosure depending on factors such as the type and composition of the adhesive 1215, type and composition of the accelerator 1405, amount of adhesive 1215 and accelerator 1405 applied, and environmental conditions such as temperature and humidity. In this way, the ends of the cells, without the positive and negative terminal disposed thereon, are secured to a center panel in the module and the movement of the cells with respect to the module is inhibited [0190] Referring now to FIG. 29 along with FIGS. 28 and 36, one or more pallets (or other handling devices) carrying the top battery cell retainer plates 1125 can be moved from a storage area to the manufacturing line at step 3405, and one or more pallets (or other handling devices) carrying the flexible circuits 1136 can be moved from a storage area to the manufacturing line at step 3410. The top battery cell retainer plates 1125 and the flexible circuits 1136 can be depalletized at step 3415. Data can be captured and logged at step 3420 on the top battery cell retainer plate 1125 and the flexible circuit 1136 identification information such as manufacturer, lot number, model number, serial number, and date of manufacture. At step 3425, each of the flexible circuits 1136 can be assembled with one of the top battery cell retainer plates 1125. In various embodiments, the flexible circuit 1136 can be heat staked to the top battery cell retainer plate 1125 by ultrasonic welding, heat welding, or any other technique known in the art. Alternatively, the top battery cell retainer plate 1125 and flexible circuit 1136 can be assembled by any mechanical method known in the art.

[0191] Referring to FIGS. 43A and 43B according to various embodiments along with FIG. 36, the top battery cell retainer plate 1125 can have a plurality of studs 1805 dispersed across a surface. The flexible circuit 1136 can comprise a corresponding plurality of clearance holes 1810 that align with the studs 1805. When the flexible circuit 1136 is assembled with the top battery cell retainer plate 1125, the studs 1805 can protrude through the clearance holes 1810. The heat staking (or other) process can melt or otherwise deform the studs 1805, thereby coupling the flexible circuit 1136 to the top battery cell retainer plate 1125.

[0192] At step 3430, a height of the studs 1805 (e.g., stake height) can be measured to ascertain that the studs have been deformed sufficiently that they will not interfere with later attachment of the cover 1135. Assemblies that fail the test can be sent for rework at step 3435, and data collected during the test can be logged at step 3440. Assemblies that pass the test can be processed further at step 3445 where the flexible circuit 1136 can be coupled to each of the battery cells.

[0193] Referring back to FIGS. 41 and 43B, the battery cell electrical connection end 1206 (opposite the end of the battery cell 710 that received the adhesive 1215) can comprise a center electrode 1605 and an outer rim electrode 1610. Each of the electrodes 1605, 1610 can be coupled to the flexible circuit 1136 to complete an electric circuit. The center electrode 1605 can align with openings 1815 in the flexible circuit 1136, and the outer rim electrode 1610 can align with tabs 1810 located adjacent to each opening 1815. At step 3445, the tabs 1810 can be bent inwards (towards the battery cell 710) slightly to reduce or eliminate any gap between the outer rim electrode 1610 and the tab 1810.

[0194] Now referring back to FIG. 28, the assembly of the top battery cell retainer plate 1125 and the flexible circuit 1136 can be joined in the process flow with the module shell 1105 with assembled battery cells 710 at step 3315. The top battery cell retainer plate 1125 and the flexible circuit 1136 assembly can be placed on the module cell 1105 across the first opening 1145 as illustrated according to various embodiments in FIGS. 44A and 44B. An entire seam (as indicated by the arrows in FIG. 44B) between an outer edge of the top battery cell retainer plate 1125 and an upper edge of the module shell 1105 defining the first opening 1145 can be laser welded (or other joining method known in the art) at step 3320.

[0195] At step 3325, the flexible circuit 1136 (now rigidly coupled to the module cell 1105 immediately above the electrical connection end 1206 of the battery cells 710) can be welded or otherwise coupled to the electrical connection end 1206 of the battery cells 710. In various embodiments, an optical scan can be conducted to ascertain positions of each of the battery cells 710 relative to one or more fiducials (not shown) on the module shell 1105 to establish 2-dimensional X-Y coordinates of each battery cell 710. In addition, the Z height of each battery cell 710 can be determined during the scan. The optical scan data can be compared to stored 3-dimensional CAD data to fix the position of the battery cells 710 with the rest of the battery module 1100 structure, including the flexible circuit 1136. A laser welding tab 1810 holding fixture can then be placed on top of the flexible circuit 1136. The holding fixture can comprise spring-loaded fingers that can press the tabs 1810 into contact with the outer rim electrodes 1610 and the flexible circuit openings 1815 into contact with the center electrodes 1605. A second optical scan can then be completed to determine the final Z height. The laser welder can then weld the tabs 1810 to the outer rim electrodes 1610 and the flexible circuit openings 1815 to the center electrodes 1605. In addition, the laser welder can weld the copper rod 1112 to the flexible circuit 1136. While the above description is presented in terms of laser welding, any other connection methodology known in the art can be substituted for laser welding and remain within the scope of the present disclosure. Data collected by the optical scans can be logged at step 3330.

[0196] Referring now to the process flow diagram of FIG. 30, the module shell 1105 can be flipped at step 3505 to expose the second opening 1150. The process flow for assembling a second half of the battery module 1100 can be initiated at step 3510. The process steps for assembling the second half of the battery module 1100 are essentially the same as described above for the first half of the battery module 1100, with the exception of the depalletizing the module shells 1105, laser etching of the module shells 1105, and placement of the circuit board 1110 and copper bar 1112 that occurs at steps 3205 through 3240. Thus, steps 3510 through 3550 of FIG. 30 correspond to steps 3110 through 3150 of FIG. 26; steps 3605 through 3615 of FIG. 31 correspond to steps 3245 through 3255 of FIG. 27; steps 3620 through 3630 of FIG. 31 correspond to steps 3305 through 3315 of FIG. 28; steps 3705 through 3745 of FIG. 32 correspond to steps 3405 through 3445 of FIG. 29; and steps 3805 through 3815 correspond to steps 3320 through 3330 of FIG. 28.

[0197] Beginning now at step 3820 of FIG. 33, according to various embodiments the circuit board 1110 can be coupled to each of the flexible circuits 1136. At this point, the battery module 1100 can be electrically tested at step 3825. The electrical test can ascertain that every battery cell 710 is in communication with the corresponding flexible circuit 1136, that each of the flexible circuits 1136 is in communication with the copper bar 1112 and the circuit board 1110. The test can also ascertain the functionality of the circuit board 1110 such as monitoring the charge on each battery cell 710, voltage across the battery module 1100, resistance across any portion of the electrical circuit of the battery module 1100, and any desired functionality. Any battery modules 1100 that fail the electrical testing of step 3825 can be reworked at step 3830. Data obtained during the electrical test and rework process can be logged at step 3835.

[0198] Referring now to FIG. 34 in conjunction with FIG. 36, one or more pallets (or other handling devices) carrying the covers 1135 can be moved from a storage area to the manufacturing line at step 3905. The covers 1135 can be depalletized at step 3910. Data can be captured and logged at step 3915 on the cover 1135 identification information such as manufacturer, lot number, model number, serial number, and date of manufacture. At step 3920, the cover 1135 can be placed across the first opening 1145 to enclose the first half of the battery module 1100 as illustrated in FIG. 45. An entire seam between an outer edge of the cover 1135 and an upper edge of the module shell 1105 defining the first opening 1145 can be laser welded (or other joining method known in the art) at step 3925. Data obtained during the laser welding process can be logged at step 3930. At step 3935 the module shell 1105 can be flipped to expose the second opening 1150. Steps 3940 through 3965 can duplicate previously described steps 3905 through 3925 to attach the cover 1135 across the second opening 1150.

[0199] Referring now to FIG. 35 in conjunction with FIG. 36, one or more O- rings 1140 can be moved from a storage area to the manufacturing line at step 3005. Data can be captured and logged at step 3010 on the O-ring 1140 identification information such as manufacturer, lot number, model number, serial number, and date of manufacture. At step 3015, an O-ring 1140 can be placed on each port 1170 of the covers 1135 as illustrated in FIG. 46A according to various embodiments. FIG. 46B illustrates the O-rings 1140 in place on the ports 1170. The completed battery module 1100 can then be leak tested at step 3020. Battery modules 1100 that fail the leak test can be reworked at step 3025, and data collected during the leak test and rework process can be logged at step 3030. Battery modules 1100 that pass the leak test can be moved to the next process at step 3035.

[0200] With respect to the process flow steps illustrated according to various embodiments in FIGS. 26-35 movement of parts, assemblies, and supplies is described. The actual movement can take place by a variety of mechanisms, and selection of a particular mechanism can take into account factors such as number of items being moved, weight of items being moved, distance of movement, queuing space at a work station, availability of automation, and the like. The movement can comprise placing items in a container and physically moving the container to the next work stations, placing the container on a manual or automated conveyor, placing the containers on a manual or automated transport vehicle, placing the items or container in position for robotic movement, and the like. Any such movement mechanism can be employed at any of the process flow steps of FIGS. 26-35 as deemed appropriate.

[0201] FIG. 47 is a flowchart of an exemplary method 2200 for assembly of a battery module 1100. At step 2205, a battery module shell 1105 can be obtained. A plurality of battery cells 710 can be placed in the battery module shell 1105 at step 2210. At step 2215, the battery cells 710 can be electrically coupled, and a control circuit 1110 can be electrically coupled to the battery cells 710 at step 2220.

[0202] FIG. 48 is a flowchart of an exemplary method 2300 for assembly of a battery module 1100. At step 2305, a battery module shell 1105 for containing battery cells 710 can be obtained. The module shell 1105 can have a retainer plate 1175 with rows of openings adapted to at least partially receive battery cells 710 therein. At step 2310, battery cells 710 can be arranged into rows corresponding to the rows of openings in the retainer plate 1175. At least one row of the battery cells 710 can be robotically grasped at step 2315. The battery cells 710 can be placed into at least one row of openings in the retainer plater 1175 while simultaneously electrically testing each battery cell 710. At step 2320, the battery cells 710 can be electrically coupled, and a control circuit 1110 can be electrically coupled to the battery cells 710 at step 2325.

[0203] FIG. 49 is a flowchart of an exemplary method 2400 for assembly of a battery module. At step 2405, a battery module shell 1105 for containing battery cells 710 can be obtained. The module shell 1105 can have a retainer plate 1175 with rows of openings adapted to at least partially receive battery cells 710 therein. At step 2410, battery cells 710 can be arranged into rows corresponding to the rows of openings in the retainer plate 1175. The battery cells 710 can have an electrode end 1206 and a non-electrode end 1205. At least one row of the battery cells 710 can be robotically grasped at step 2415 and the following steps can be performed while continuing to grasp the battery cells 710: electrically testing each battery cell 710 (step 2420); placing an adhesive 1215 on the non- electrode end 1205 of each battery cell 710 (step 2425); and placing the non-electrode end 1205 of the battery cells 710 into the openings in the retainer plate 1175 such that the adhesive 1215 contacts the retainer plate 1175 (step 2430). At step 2435, the battery cells 710 can be electrically coupled, and a control circuit 1110 can be electrically coupled to the battery cells 710 at step 2440.

[0204] The foregoing description details certain embodiments of the systems, devices, and methods disclosed herein. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the devices and methods can be practiced in many ways. As is also stated above, it should be noted that the use of particular terminology when describing certain features or aspects of the invention should not be taken to imply that the terminology is being re-defined herein to be restricted to including any specific characteristics of the features or aspects of the technology with which that terminology is associated. The scope of the disclosure should therefore be construed in accordance with the appended claims and any equivalents thereof.

[0205] With respect to the use of any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

[0206] It is noted that the examples may be described as a process. Although the operations may be described as a sequential process, many of the operations can be performed in parallel, or concurrently, and the process can be repeated. In addition, the order of the operations may be rearranged. A process is terminated when its operations are completed. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc.

[0207] It will be appreciated by those skilled in the art that various modifications and changes may be made without departing from the scope of the described technology. Such modifications and changes are intended to fall within the scope of the embodiments, as defined by the appended claims. It will also be appreciated by those of skill in the art that parts included in one embodiment are interchangeable with other embodiments; one or more parts from a depicted embodiment can be included with other depicted embodiments in any combination. For example, any of the various components described herein and/or depicted in the Figures may be combined, interchanged, or excluded from other embodiments.

[0208] Those of skill would further appreciate that any of the various illustrative schematic drawings described in connection with the aspects disclosed herein may be implemented as electronic hardware (e.g., a digital implementation, an analog implementation, or a combination of the two, which may be designed using source coding or some other technique), various forms of program or design code incorporating instructions, or combinations of both.

[0209] The various circuitry, controllers, microcontroller, or switches, and the like, that are disclosed herein may be implemented within or performed by an integrated circuit (IC), an access terminal, or an access point. The IC may comprise a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, electrical components, optical components, mechanical components, or any combination thereof designed to perform the functions described herein, and may execute codes or instructions that reside within the IC, outside of the IC, or both.

[0210] The functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a tangible, non-transitory computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer- readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. A computer-readable medium may be in the form of a non-transitory or transitory computer-readable medium.

[0211] The term "determining" encompasses a wide variety of actions and, therefore, "determining" can include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database, or another data structure), ascertaining, and the like. Also, "determining" can include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. Determining can also include resolving, selecting, choosing, establishing, and the like.

[0212] Though described herein with respect to a vehicle, as would be readily appreciated by one of ordinary skill in the art, various embodiments described herein may be used in additional applications, such as in energy-storage systems for wind and solar power generation. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed current carrier and battery module. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.

Claims

WHAT IS CLAIMED IS:

1. An energy-storage system for a vehicle comprising:

a plurality of modules, each module comprising two half modules coupled together, each half module including:

a plurality of cells, the cells being cylindrical rechargeable lithium-ion cells each having a first end and a second end, the first end distal from the second end, and having an anode terminal and a cathode terminal being disposed at the first end;

a current carrier electrically coupled to the cells, the cathode terminal of each of the cells being coupled to a respective first contact of the current carrier, the anode terminal of each of the cells being coupled to a respective second contact of the current carrier;

a blast plate disposed substantially parallel to the current carrier such that the cells are disposed between the current carrier and the blast plate; and an enclosure having the cells, current carrier, and blast plate disposed therewithin, the enclosure including a coolant input port, a coolant output port, and a power connector electrically coupled to the current carrier; the enclosure having a coolant sub-system for circulating coolant being pumped into the enclosure through the coolant input port and out of the enclosure through the coolant output port such that each of the cells is at approximately the same predetermined temperature;

a tray having the plurality of modules disposed therein, the tray including: a positive bus bar; and

a negative bus bar, the positive and negative bus bars being separately electrically coupled to the power connectors associated with the plurality of modules; and

a coolant system for circulating coolant being pumped into the tray such that each of the modules is at approximately the same predetermined temperature.

2. The energy-storage system of claim 1, wherein the current carrier includes a plurality of fuses each electrically coupled to the respective first contact.

3. The energy-storage system of claim 1, wherein the cathode terminal of each cell is welded to the respective first contact of the current carrier and the anode terminal of each cell is welded to the respective second contact of the current carrier.

4. The energy-storage system of claim 3, wherein the welding is laser welding.

5. The energy-storage system of claim 1, wherein the blast plate is closer to the second end of the cells than to the first end, each of the cells being oriented to allow venting into the blast plate for both half modules.

6. The energy-storage system of claim 1, wherein the tray is sized and arranged to be disposed in the chassis of an electric vehicle.

7. The energy-storage system of claim 1, wherein the current carrier is held in the enclosure by at least one plastic stake.

8. The energy-storage system of claim 1, wherein at least two adjacent modules of the plurality of modules are fluidly and electrically coupled to each other.

9. The energy-storage system of claim 1, wherein the first contact of the current carrier is a positive contact and the second contact of the current carrier is a negative contact.

10. The energy-storage system of claim 1, wherein the cells are oriented and mounted horizontally in each half module.

11. The energy- storage system of claim 1, wherein the cells are disposed between the current carrier and the blast plate such that an exterior side of each of the cells is not in contact with the exterior sides of other cells, the coolant sub-system circulating coolant among and between the cells to provide submerged, substantially even distributed cooling.

12. The energy-storage system of claim 1, wherein air pockets are formed using channels in a space between the current carrier and the blast plate that is not occupied by the cells.

13. The energy-storage system of claim 1, wherein the coolant system employs parallel cooling.

14. The energy-storage system of claim 11, wherein the coolant flows through each half module along a cylindrical body of a battery cell within the half module.

15. The energy-storage system of claim 1, wherein the modules are arranged in a plurality of strings, each string of the plurality of strings including a plurality of modules.

16. The energy-storage system of claim 1, wherein the coolant comprises at least one of: a synthetic oil, ethylene glycol and water, and a liquid dielectric.

17. The energy-storage system of claim 15, wherein the coolant flows through the strings in parallel and the coolant flows within each respective string of the battery modules in parallel.

18. An energy-storage system for a vehicle comprising:

a plurality of modules in a battery pack, each module including:

a plurality of cells, the cells being cylindrical rechargeable cells; the cells being oriented and mounted horizontally in each module;

a current carrier electrically coupled to the cells, a cathode terminal of each of the cells being coupled to a respective first contact of the current carrier, an anode terminal of each of the cells being coupled to a respective second contact of the current carrier;

a blast plate disposed substantially parallel to the current carrier such that the cells are disposed between the current carrier and the blast plate; and an enclosure having the cells, current carrier, and blast plate disposed therewithin, the enclosure having a coolant sub-system for circulating coolant being pumped into the enclosure through a coolant input port and out of the enclosure through a coolant output port, the cells being disposed between the current carrier and the blast plate such that an exterior side of each of the cells is not in contact with the exterior sides of other cells, the coolant sub-system circulating coolant among and between the cells to provide submerged, distributed cooling such that each of the cells is at approximately the same predetermined temperature;

19. The energy-storage system of claim 18, wherein the coolant system creates a pressure gradient for coolant being pumped into the battery pack and out of the battery pack, the pressure gradient within the battery pack providing circulation of the coolant so as to minimize a temperature gradient within the battery pack.

20. An energy-storage system for a vehicle comprising:

a plurality of cells, the cells being cylindrical rechargeable lithium-ion cells having an anode terminal and a cathode terminal being disposed at one end, the cells being oriented and mounted horizontally in each half module; a current carrier electrically coupled to the cells, the cathode terminal of each of the cells being coupled to a respective first contact of the current carrier, the anode terminal of each of the cells being coupled to a respective second contact of the current carrier; the current carrier including a plurality of fuses each electrically coupled to the respective first contact;

a blast plate disposed substantially parallel to the current carrier such that the cells are disposed between the current carrier and the blast plate; and an enclosure having the cells, current carrier, and blast plate disposed therewithin;

a negative bus bar, the positive and negative bus bars being separately electrically coupled to power connectors associated with the plurality of modules; and

a coolant system for circulating coolant being pumped into the tray such that each of the modules and each of the cells is at approximately the same predetermined temperature.

21. An energy-storage system having parallel cooling comprising:

a plurality of modules, each module comprising two half modules coupled together, each half module including: a plurality of battery cells, the battery cells being cylindrical rechargeable battery cells each having a first end and a second end, the first end distal from the second end, and having an anode terminal and a cathode terminal being disposed at the first end;

a current carrier electrically coupled to the battery cells, the cathode terminal of each of the battery cells being coupled to a respective first contact of the current carrier, the anode terminal of each of the battery cells being coupled to a respective second contact of the current carrier;

a plate disposed substantially parallel to the current carrier such that the battery cells are disposed between the current carrier and the plate; and an enclosure having the battery cells, current carrier, and plate disposed therein, the enclosure comprising:

a coolant input port;

a coolant output port; and

a power connector electrically coupled to the current carrier, the enclosure having a coolant sub-system for circulating coolant flowing into the enclosure through the coolant input port and out of the enclosure through the coolant output port in parallel to the plurality of battery cells such that each of the battery cells is at approximately the same predetermined temperature;

a tray having the plurality of modules disposed therein; and

a coolant system for circulating coolant flowing into the tray across the plurality of modules such that each of the modules is at approximately the same predetermined temperature.

22. The energy-storage system of claim 21, wherein the coolant system creates a pressure gradient for coolant flowing into and out of each module of the plurality of modules disposed in the tray, the pressure gradient providing circulation of the coolant so as to minimize a temperature gradient between modules of the plurality of modules.

23. The energy-storage system of claim 21, wherein the cells are disposed between the current carrier and the plate such that an exterior side of each of the cells is not in contact with the exterior sides of other cells, the coolant sub-system circulating coolant among and between the cells to provide submerged, substantially even distributed cooling.

24. The energy-storage system of claim 21, wherein air pockets are formed using channels in a space between the current carrier and the plate that is not occupied by the cells, the air pockets comprising a fluid other than the coolant.

25. The energy-storage system of claim 24, wherein the coolant flows through each half module along a cylindrical body of a battery cell within the half module.

26. The energy-storage system of claim 21, wherein the modules are arranged in a plurality of strings, each string of the plurality of strings including a plurality of modules.

27. The energy-storage system of claim 26, wherein the coolant flows through the plurality of strings in parallel and the coolant flows within each string of the plurality of strings in parallel.

28. The energy-storage system of claim 21, wherein the coolant comprises at least one of a synthetic oil, ethylene glycol and water, and a liquid dielectric.

29. The energy-storage system of claim 21, wherein at least two adjacent modules of the plurality of modules are fluidly and electrically coupled to each other.

30. The energy-storage system of claim 21, wherein the cells are oriented and mounted horizontally in each half module.

31. An energy-storage system having parallel cooling comprising:

a plurality of modules in a battery pack, each module including:

a plate disposed substantially parallel to the current carrier such that the cells are disposed between the current carrier and the plate; and

an enclosure having the cells, current carrier, and plate disposed therein, the enclosure comprising a coolant sub-system for circulating coolant flowing into the enclosure through a coolant input port and out of the enclosure through a coolant output port, the cells being disposed between the current carrier and the plate such that an exterior side of each of the cells is not in contact with the exterior sides of other cells, the coolant sub-system circulating coolant in parallel among and between the cells to provide submerged, distributed cooling such that each of the cells is at approximately the same predetermined temperature;

a tray having the plurality of modules disposed therein; and

a coolant system for circulating coolant flowing into the tray across the plurality of modules in parallel such that each of the modules is at approximately the same predetermined temperature.

32. The energy-storage system of claim 31, wherein the coolant system creates a pressure gradient for coolant flowing into the battery pack and out of the battery pack, the pressure gradient within the battery pack providing circulation of the coolant so as to minimize a temperature gradient within the battery pack.

33. The energy-storage system of claim 31, wherein the cells are disposed between the current carrier and the plate such that an exterior side of each of the cells is not in contact with the exterior sides of other cells, the coolant sub-system circulating coolant among and between the cells to provide submerged, substantially even distributed cooling.

34. The energy-storage system of claim 31, wherein air pockets are formed using channels in a space between the current carrier and the plate that is not occupied by the cells, the air pockets comprising a fluid other than the coolant.

35. The energy-storage system of claim 34, wherein the coolant flows through each module along a cylindrical body of a battery cell within the module.

36. The energy-storage system of claim 31, wherein the modules are arranged in a plurality of strings, each string of the plurality of strings including a plurality of modules.

37. The energy-storage system of claim 36, wherein the coolant flows through the plurality of strings in parallel and the coolant flows within each string of the plurality of strings in parallel.

38. The energy-storage system of claim 31, wherein the coolant comprises at least one of a synthetic oil, ethylene glycol and water, and a liquid dielectric.

39. The energy-storage system of claim 31, wherein at least two adjacent modules of the plurality of modules are fluidly and electrically coupled to each other.

40. A container of an energy-storage system having parallel cooling comprising: a plurality of module housings, each module comprising two half module housings coupled together, each half module housing is configured to receive

a plurality of cells each having an anode terminal and a cathode terminal being disposed at one end,

the half module housing further including:

a current carrier electrically coupled to the cells, the cathode terminal of each of the cells being coupled to a respective first contact of the current carrier, the anode terminal of each of the cells being coupled to a respective second contact of the current carrier; the current carrier including a plurality of fuses each electrically coupled to the respective first contact;

a retainer element disposed substantially parallel to the current carrier and configured to mount the cells horizontally within each half module housing; and

an enclosure having the current carrier and the retainer element disposed therein;

a tray having the plurality of module housings disposed therein, the tray including:

a positive bus bar; and

a negative bus bar, the positive and negative bus bars being separately electrically coupled to power connectors associated with the plurality of module housings; and

a coolant system for circulating coolant flowing into the tray across the plurality of module housings and battery cells in parallel such that each of the module housings and each of the cells is at approximately the same predetermined temperature.

41. A current carrier comprising:

a positive power plane; a negative power plane;

a dielectric isolation layer disposed between the positive power plane and the negative power plane;

a plurality of positive contacts formed in the positive power plane, the positive contacts being for electrical coupling to a respective cathode terminal of each battery cell of a plurality of battery cells; and

a plurality of negative contacts formed in the negative power plane, the negative contacts being for electrically coupling to a respective anode terminal of each battery cell of the plurality of battery cells.

42. The current carrier of claim 41 further comprising:

a plurality of fuses formed in the positive power plane, each fuse of the plurality of fuses electrically coupled to the respective positive contact of the plurality of positive contacts.

43. The current carrier of claim 42 further comprising:

a signal layer;

a second dielectric isolation layer disposed adjacent to the signal layer;

at least one sensor, each sensor of the at least one sensor being communicatively coupled to the signal layer and disposed adjacent to a respective battery cell of at least one of the plurality of battery cells; and

a communications connector communicatively coupled to the signal layer.

44. The current carrier of claim 43 further comprising:

a power connection electrically coupled separately to the positive power plane and the negative power plane.

45. The current carrier of claim 41, wherein the electrical coupling comprises a weld.

46. The current carrier of claim 45, wherein the weld is a laser weld.

47. The current carrier of claim 41 further comprising: a printed circuit board comprising at least one of copper, FR-2, FR-3, FR-4, FR-5, FR-6, CEM-1, CEM-2, CEM-3, CEM-4, and CEM-5.

48. The current carrier of claim 41 further comprising: a flexible printed circuit comprising at least one of copper foil, polyester, polyimide, polyethylene naphthalate, polyetherimide, fluoropolymers, and copolymers.

49. The current carrier of claim 41, wherein the battery cells are cylindrical rechargeable cells.

50. The current carrier of claim 41 further comprising a plurality of holes, the holes conducting a coolant from a first side of the current carrier to a second side of the current carrier.

51. A vehicle energy-storage system comprising:

a plurality of modules, each module comprising:

a plurality of battery cells, the battery cells each having a first end and a second end, the first end distal from the second end, and having an anode terminal and a cathode terminal being disposed at the first end, the cells being oriented and mounted horizontally in each half module;

a current carrier comprising:

a positive power plane;

a negative power plane;

a plurality of positive contacts formed in the positive power plane, the positive contacts being electrically coupled to a respective cathode terminal of each battery cell of the plurality of battery cells; and

a plurality of negative contacts formed in the negative power plane, the negative contacts being electrically coupled to a respective anode terminal of each battery cell of the plurality of battery cells; and an enclosure having the battery cells and current carrier disposed therein, the enclosure including a power connector electrically coupled to the positive power plane and negative power plane;

a main power connector electrically coupled to the power connectors of the two half modules; and a blast plate disposed substantially parallel to the current carrier such that the battery cells are disposed between the current carrier and the blast plate;

a negative bus bar, the positive and negative bus bars being separately electrically coupled to the main power connectors of the plurality of modules; and

52. The vehicle energy-storage system of claim 51, wherein the current carrier further comprises:

53. The vehicle energy-storage system of claim 51, wherein the current carrier further comprises:

a signal layer;

a second dielectric isolation layer disposed adjacent to the signal layer;

a communications connector communicatively coupled to the signal layer.

54. The vehicle energy-storage system of claim 51, wherein the current carrier further comprises:

the power connection electrically coupled separately to the positive power plane and the negative power plane.

55. The vehicle energy-storage system of claim 51, wherein:

each positive contact of the plurality of positive contacts is welded to the respective cathode terminal of each battery cell of the plurality of battery cells; and each negative contact of the plurality of negative contacts is welded to the respective anode terminal of each battery cell of the plurality of battery cells.

56. The vehicle energy- storage system of claim 55, wherein the welding is laser welding.

57. The vehicle energy-storage system of claim 51, wherein the current carrier comprises: a printed circuit board comprising at least one of copper, FR-2, FR-3, FR-4, FR-5, FR-6, G-10, CEM-1, CEM-2, CEM-3, CEM-4, and CEM-5.

58. The vehicle energy-storage system of claim 51, wherein the current carrier comprises: a flexible printed circuit comprising at least one of copper foil, polyester, polyimide, polyethylene naphthalate, polyetherimide, fluoropolymers, and copolymers.

59. The vehicle energy-storage system of claim 51, wherein the battery cells are cylindrical rechargeable lithium-ion cells.

60. A vehicle energy-storage system comprising:

a plurality of modules, each module comprising:

a plurality of battery cells, the battery cells being cylindrical rechargeable lithium-ion cells each having a first end and a second end, the first end distal from the second end, and having an anode terminal and a cathode terminal being disposed at the first end, the cells being oriented and mounted horizontally in each module;

a current carrier comprising:

a positive power plane;

a negative power plane;

a plurality of positive contacts formed in the positive power plane, the positive contacts being for electrical coupling to a respective cathode terminal of each battery cell of the plurality of battery cells; and

a plurality of negative contacts formed in the negative power plane, the negative contacts being for electrical coupling to a respective anode terminal of each battery cell of the plurality of battery cells;

an enclosure having the battery cells and current carrier disposed therein, the enclosure including a power connector electrically coupled to the power connections;

a main power connector electrically coupled to the power connector; and

a blast plate disposed substantially parallel to the current carrier such that the battery cells are disposed between the current carrier and the blast plate;

61. A battery module comprising:

an enclosure having a base, the base having a plurality of first holes disposed therein, the enclosure including a coolant input port and a coolant output port; the enclosure having a coolant sub-system for circulating coolant being directed into the enclosure through the coolant input port and the plurality of first holes and out of the enclosure through the coolant output port;

a center divider affixed to the enclosure;

a module cover coupled to the enclosure at an opposite end of the module from the center divider;

a retainer disposed within the enclosure and configured to support a plurality of cells;

a current carrier disposed between the module cover and the retainer; and the plurality of cells disposed between the current carrier and the center divider, the cells being coupled to and supported by the retainer.

62. The battery module of claim 61, wherein the plurality of first holes each have a diameter in a range from 0.1 mm - 5 mm.

63. The battery module of claim 62, wherein the plurality of first holes are disposed on the base such that each first hole of the plurality of first holes receives substantially the same inlet pressure and approximately the same volume flow is maintained through each first hole.

64. The battery module of claim 63, wherein the substantially same inlet pressure is in a range of 0.05 psi - 5 psi and the approximately same volume flow is 0.05 L/min - 5 L/min.

65. The battery module of claim 61, wherein the module cover, the enclosure, and the center divider are each comprised of at least one of: polycarbonate, polypropylene, acrylic, nylon, and acrylonitrile butadiene styrene (ABS), and the module cover and the center divider are each affixed to the enclosure, forming a hermetic seal.

66. The battery module of claim 61, wherein the module cover and center divider comprise laser-transmissive polycarbonate, the enclosure comprises laser-absorptive polycarbonate, and the module cover and the center divider are each affixed to the enclosure, forming a hermetic seal.

67. The battery module of claim 61, further comprising:

a tray having the plurality of modules disposed therein, the tray including: a positive bus bar;

a plurality of lateral supports; and

68. The battery module of claim 61, wherein the retainer includes a plurality of second holes configured to direct the coolant from the base of the enclosure to the current carrier.

69. The battery module of claim 68, wherein the current carrier includes a plurality of third holes configured to direct the coolant outside of the enclosure.

70. The battery module of claim 69, wherein the plurality of second holes and the plurality of third holes are substantially aligned.

71. The battery module of claim 61, wherein the current carrier is coupled to the retainer through a plurality of stubs formed on the retainer.

72. A battery comprising a plurality of the battery modules of claim 1, wherein at least some of the plurality of battery modules are fluidically coupled in series.

73. An energy-storage system for a vehicle comprising:

a plurality of modules fluidly communicating with each other, each module including:

an enclosure including a base, the base having a plurality of holes disposed therein, the enclosure including a coolant input port, a coolant output port, and a power connector; the enclosure having a coolant sub-system for circulating coolant being directed into the enclosure through the coolant input port and the plurality of holes and out of the enclosure through the coolant output port;

a blast plate coupled to the base of the enclosure;

a module cover disposed at an opposite end of the module from the blast plate;

a current carrier disposed between the module cover and the retainer and electrically coupled to the power connector; and

the plurality of cells disposed in the enclosure and secured by the retainer and the base, electrical connections being formed between the plurality of cells and the current carrier.

74. The energy-storage system of claim 73, wherein the plurality of holes each have a diameter in a range from 0.1 mm - 5 mm.

75. The energy-storage system of claim 74, wherein the plurality of holes are disposed on the base such that each hole of the plurality of holes receives substantially the same inlet pressure and approximately the same volume flow is maintained through each hole.

76. The energy-storage system of claim 75, wherein the substantially same inlet pressure is in a range of 0.05 psi - 5 psi and the approximately same volume flow is 0.05 L/min - 5 L/min.

77. The energy-storage system of claim 73, wherein the module cover, the enclosure, and the blast plate are each comprised of at least one of: polycarbonate, polypropylene, acrylic, nylon, and acrylonitrile butadiene styrene (ABS), and the module cover and the blast plate are each affixed to the enclosure, forming a hermetic seal.

78. The energy-storage system of claim 73, wherein the module cover and blast plate comprise laser-transmissive polycarbonate, the enclosure comprises laser-absorptive polycarbonate, and the module cover and the blast plate are each affixed to the enclosure using at least laser welding, forming a hermetic seal.

79. The energy-storage system of claim 73 further comprising:

a plurality of lateral supports; and

a coolant system for circulating coolant being pumped into the tray such that each of the modules is at approximately the same predetermined temperature,

wherein the enclosure further includes a first tab disposed at a first end of the enclosure and a second tab disposed at a second end of the enclosure, the first end being distal from the second end, and the first tab and the second tab being mechanically coupled to a respective lateral support of the plurality of lateral supports.

80. An energy-storage module for a vehicle comprising:

a housing enclosing a first group of battery cells and a second group of battery cells, the housing including a coolant inlet port configured to receive coolant and a coolant outlet port configured to release coolant; and

a cooling system formed within the housing between the coolant inlet port and the coolant outlet port, the cooling system is configured to separate the coolant into a first coolant flow directed to the first group of battery cells and a second coolant flow directed to the second group of battery cells,

wherein the first coolant flow flows over the first group of battery cells in a first direction and the second coolant flow flows over the second group of battery cells in a second direction, and

wherein the first direction and the second direction are opposite to each other.

81. A current carrier comprising:

a circuit board configured to be electrically connected to a plurality of battery cells, each battery cell comprising a first end, an anode terminal disposed on the first end of the battery cell, and a cathode terminal disposed on the first end of the battery cell, each of the plurality of battery cells being disposed such that the first end of each of the plurality of battery cells is oriented in the same direction, the circuit board comprising:

a first layer having a first group of positive contacts configured to be electrically connected to cathode terminals of a first group of battery cells among the plurality of battery cells; and

a second layer having a first group of negative contacts configured to be electrically connected to anode terminals of the first group of battery cells.

82. The current carrier of claim 81, wherein the first layer further includes a second group of negative contacts configured to be electrically connected to anode terminals of a second group of battery cells among the plurality of battery cells, and wherein the second layer further includes a second group of positive contacts configured to be electrically connected to cathode terminals of the second group of battery cells.

83. The current carrier of claim 81, wherein the first group of battery cells are electrically connected in parallel.

84. The current carrier of claim 82, wherein the first group of positive contacts and the second group of negative contacts form an electrically connected node.

85. The current carrier of claim 84, wherein the first group of battery cells and the second group of battery cells are electrically connected in series.

86. The current carrier of claim 82, wherein the number of battery cells in the first group is equal to the number of battery cells in the second group.

87. The current carrier of claim 81, wherein the circuit board further comprises: a base layer having a first side and a second side wherein the first layer is disposed on the first side of the base layer and the second layer is disposed on the second side of the base layer.

88. A battery module comprising:

a plurality of battery cells, each battery cell comprising a first end, an anode terminal disposed on the first end of the battery cell, and a cathode terminal disposed on the first end of the battery cell, each of the plurality of battery cells being disposed such that the first end of each of the plurality of battery cells is oriented in the same direction; and

a current carrier comprising a circuit board, the circuit board comprising a first layer having a first group of positive contacts configured to be electrically connected to cathode terminals of a first group of battery cells among the plurality of battery cells; and a second layer having a first group of negative contacts configured to be electrically connected to anode terminals of the first group of battery cells.

89. The battery module of claim 88, wherein the first layer further includes a second group of negative contacts configured to be electrically connected to anode terminals of a second group of battery cells among the plurality of battery cells, and wherein the second layer further includes a second group of positive contacts configured to be electrically connected to cathode terminals of the second group of battery cells.

90. The battery module of claim 88, wherein the first group of battery cells are electrically connected in parallel.

91. The battery module of claim 89, wherein the first group of positive contacts and the second group of negative contacts form an electrically connected node.

92. The battery module of claim 91, wherein the number of battery cells in the first group is equal to the number of battery cells in the second group.

93. The battery module of claim 89, wherein the circuit board further comprises: a base layer having a first side and a second side wherein the first layer is disposed on the first side of the base layer and the second layer is disposed on the second side of the base layer.

94. A vehicle comprising: a battery module, the battery module comprising:

95. The vehicle of claim 94, wherein the first layer further includes a second group of negative contacts configured to be electrically connected to anode terminals of a second group of battery cells among the plurality of battery cells, and wherein the second layer further includes a second group of positive contacts configured to be electrically connected to cathode terminals of the second group of battery cells.

96. The vehicle of claim 94, wherein the first group of battery cells are electrically connected in parallel.

97. The vehicle of claim 95, wherein the first group of positive contacts and the second group of negative contacts form an electrically connected node.

98. The vehicle of claim 97, wherein the first group of battery cells and the second group of battery cells are electrically connected in series.

99. The vehicle of claim 95, wherein the number of battery cells in the first group is equal to the number of battery cells in the second group.

100. The vehicle of claim 94, wherein the circuit board further comprises:

a base layer having a first side and a second side wherein the first layer is disposed on the first side of the base layer and the second layer is disposed on the second side of the base layer.

101. An electric vehicle battery pack comprising: a rack configured to couple a plurality of independently removable battery strings to the vehicle, the battery strings configured to be selectively coupled in parallel to a vehicle power bus, the battery strings comprising:

an individual battery string housing;

a plurality of electrochemical cells disposed within the housing;

a circuit for electrically connecting the plurality of electrochemical cells, the circuit having a positive terminal and a negative terminal;

a positive high-voltage connector located on an exterior surface of the housing, the positive high-voltage connector electrically coupled to the positive terminal;

a negative high-voltage connector located on an exterior surface of the housing, the negative high-voltage connector electrically coupled to the negative terminal;

a switch disposed within the housing and electrically connected in series with at least the positive high- voltage connector; and

a string control unit disposed within the housing, the string control unit electrically coupled to and configured to control the switch.

102. The electric vehicle battery pack of Claim 101, wherein each battery string further comprises:

a coolant inlet located on an exterior surface of the housing and configured to couple with and sealingly uncouple from an external coolant supply conduit;

a coolant outlet located on an exterior surface of the housing and configured to couple with and sealingly uncouple from an external coolant return conduit; and an auxiliary connector located on an exterior surface of the housing and configured to couple with at least one of an external communications system and an external low-voltage power supply.

103. The electric vehicle battery pack of Claim 102, wherein the auxiliary connector comprises a CAN bus connector configured to couple with a CAN bus.

104. The electric vehicle battery pack of Claim 102, further comprising one or more thermal barriers configured to at least partially insulate adjacent battery strings.

105. The electric vehicle battery pack of Claim 101, wherein each battery string comprises a plurality of battery modules connected in series, each battery module comprising a plurality of electrochemical cells.

106. The electric vehicle battery pack of Claim 105, wherein each battery string further comprises a plurality of module monitoring boards, each module monitoring board communicatively coupled to one of the plurality of battery modules and configured to monitor at least one of a current, a voltage, and a temperature associated with the one battery module.

107. The electric vehicle battery pack of Claim 106, wherein the plurality of module monitoring boards are communicatively coupled to the string control unit, and wherein the string control unit is configured to control the switch based at least in part on data received from one or more of the module monitoring boards.

108. The electric vehicle battery pack of Claim 101, wherein the switch comprises a magnetic contactor configured to be in a disconnected position when the magnetic contactor is not energized.

109. An electric vehicle battery pack comprising:

a rack configured to couple a plurality of independently removable battery strings to the vehicle, the battery strings configured to be selectively coupled in parallel to a vehicle power bus, the battery strings comprising: an individual battery string housing;

a plurality of electrochemical cells disposed within the housing;

a negative high-voltage connector located on an exterior surface of the housing, the negative high-voltage connector electrically coupled to the negative terminal; a coolant inlet located on an exterior surface of the housing and configured to couple with and sealingly uncouple from an external coolant supply conduit;

a coolant outlet located on an exterior surface of the housing and configured to couple with and sealingly uncouple from an external coolant return conduit; and

an auxiliary connector located on an exterior surface of the housing and configured to couple with at least one of an external communications system and an external low-voltage power supply.

110. The electric vehicle battery pack of Claim 109, wherein each battery string further comprises a switch disposed within the housing and electrically connected in series with at least the positive terminal.

111. The electric vehicle battery pack of Claim 110, wherein each battery string further comprises a string control unit disposed within the housing, the string control unit electrically coupled to and configured to control the switch.

112. The electric vehicle battery pack of Claim 111, wherein the auxiliary connector is configured to couple with the external low-voltage power supply, and wherein the string control unit is configured to draw electrical power from the auxiliary connector.

113. The electric vehicle battery pack of Claim 109, wherein the auxiliary connector comprises a CAN bus connector configured to connect to a CAN bus.

114. The electric vehicle battery pack of Claim 109, wherein each battery string comprises a plurality of battery modules connected in series, each battery module comprising a plurality of electrochemical cells.

115. The electric vehicle battery pack of Claim 114, wherein each battery string further comprises a plurality of module monitoring boards, each module monitoring board communicatively coupled to one of the plurality of battery modules and configured to monitor at least one of a current, a voltage, and a temperature associated with the one battery module.

116. The electric vehicle battery pack of Claim 109, further comprising one or more thermal barriers configured to at least partially insulate adjacent battery strings.

117. A method of servicing an electric vehicle, the method comprising: uncoupling a coolant supply conduit of the electric vehicle from a coolant inlet of a first battery string located within a chassis of the electric vehicle;

uncoupling a coolant return conduit of the electric vehicle from a coolant outlet of the first battery string;

uncoupling from an auxiliary connector of the first battery string at least one of a communications system of the electric vehicle and a low- voltage power supply of the electric vehicle;

uncoupling at least one high-voltage connector of the first battery string from a power bus of the electric vehicle; and

removing the first battery string from the chassis of the electric vehicle;

wherein the first battery string comprises one of a plurality of independently removable battery strings of the electric vehicle.

118. The method of Claim 117, wherein removing the first battery string comprises g the battery string in at least one of a horizontal direction and a vertical direction.

119. The method of Claim 117, wherein disengaging the at least one high-voltage connector comprises removing the battery string from the electric vehicle.

120. The method of Claim 117, further comprising:

placing a second battery string into the chassis of the electric vehicle;

coupling at least one high-voltage connector of the second battery string to the power bus;

coupling an auxiliary connector of the second battery string to at least one of the communications system and the low-voltage power supply;

coupling the coolant supply conduit to a coolant inlet of the second battery string; and

coupling the coolant return conduit to a coolant outlet of the second battery string.

121. A method for assembly of a battery module, comprising:

obtaining a battery module shell;

placing a plurality of battery cells in the battery module shell ; electrically coupling the battery cells; and

electrically coupling a control circuit to the battery cells.

122. The method of claim 121, wherein the battery module comprises a first half having a first opening and a second half having a second opening opposite the first opening.

123. The method of claim 122, further comprising placing a first plurality of battery cells in the first half and a second plurality of battery cells in the second half.

124. The method of claim 123, further comprising electrically coupling the first plurality of battery cells and electrically coupling the second plurality of battery cells.

125. The method of claim 124, further comprising electrically coupling the first plurality of battery cells to the second plurality of battery cells.

126. The method of claim 121, wherein electrically coupling the battery cells comprises coupling a single flexible circuit to all of the plurality of battery cells.

127. The method of claim 126, wherein each of the plurality of battery cells comprises a positive electrode and a negative electrode, and coupling the flexible circuit to the plurality of battery cells comprises coupling the flexible circuit to each positive electrode and each negative electrode.

128. The method of claim 127, wherein the plurality of battery cells are arranged in rows, and the flexible circuit is coupled to each positive electrode and each negative electrode in each row simultaneously.

129. A method for assembly of a battery module, comprising:

obtaining a battery module shell for containing battery cells, the module shell having a retainer plate with rows of openings adapted to at least partially receive battery cells therein;

arranging battery cells into rows corresponding to the rows of openings in the retainer plate;

robotically grasping at least one row of battery cells and placing the battery cells into at least one row of openings in the retainer plate while simultaneously electrically testing each battery cell;

electrically coupling the battery cells in the module shell; and electrically coupling a control circuit to the battery cells.

130. The method of claim 129, further comprising coupling each of the battery cells to the retainer plate.

131. The method of claim 130, wherein coupling each of the battery cells to the retainer plate comprises placing an adhesive on each of the battery cells prior to placing the battery cells into the openings in the retainer plate.

132. The method of claim 131, further comprising coating at least a portion of each opening in the retainer plate with an adhesive accelerator prior to placing the battery cells into the openings.

133. A method for assembly of a battery module, comprising:

arranging battery cells into rows corresponding to the rows of openings in the retainer plate, the batteries having an electrode end and a non-electrode end;

robotically grasping at least one row of battery cells at the electrode end and performing the following steps while continuing to grasp the battery cells:

electrically testing each battery cell;

placing an adhesive on the non-electrode end of each battery cell; placing the non-electrode end of the battery cells into the openings in the retainer plate such that the adhesive contacts the retainer plate;

134. The method of claim 133, wherein placing the adhesive on the non-electrode end of each battery cell comprises placing a designated amount of the adhesive in a ring- shaped pattern on the non-electrode end.

135. The method of claim 134, further comprising applying a force to the battery cell when placing the non-electrode end of the battery cell into the opening in the retainer plate and causing the adhesive to flow.

136. The method of claim 135, wherein causing the adhesive to flow comprises causing the adhesive to coat a portion of the non-electrode end of the battery but leaving a central portion of the non-electrode end uncovered with adhesive.

137. The method of claim 133, wherein electrically coupling the battery cells comprises coupling a single flexible circuit to the battery cells.

138. The method of claim 137, wherein each of the electrode ends of the battery cells comprises a positive electrode and a negative electrode, and coupling the flexible circuit to the battery cells comprises coupling the flexible circuit to each positive electrode and each negative electrode.

139. The method of claim 137, wherein coupling the flexible circuit to each positive electrode and each negative electrode comprises laser welding the flexible circuit to each positive electrode and to each negative electrode.

140. The method of claim 133, further comprising joining multiple battery modules together to form a battery string.

141. An electric vehicle comprising:

a motor coupled to one or more wheels of the electric vehicle; an inverter coupled to the motor;

at least a first power bus coupled to the inverter;

a first battery string having an output that is coupled to the first power bus through a first switch;

at least a second battery string different from the first battery string having an output that is coupled to the first power bus through a second switch different from the first switch; and

a battery management system coupled to at least the first switch and the second switch, the battery management system configured to selectively and independently control the open or closed state of the first switch and the second switch, thereby selectively and independently connecting the output of the first battery string and the output of the second battery string to the first power bus.

142. The electric vehicle of Claim 141, wherein each of the first and second battery strings comprises a plurality of battery modules.

143. The electric vehicle of Claim 141, wherein the battery management system comprises a plurality of module monitoring boards and a plurality of string control units, wherein each of the plurality of module monitoring boards is coupled to one of the plurality of string control units.

144. The electric vehicle of Claim 142, wherein each of the plurality of battery modules of the first battery string is coupled to one of a plurality of module monitoring boards of the first battery string, wherein each of the plurality of battery modules of the second battery string is coupled to one of a plurality of module monitoring boards of the second battery string.

145. The electric vehicle of Claim 144, wherein the plurality of module monitoring boards of the first battery string are in communication with a first battery string control unit, wherein the plurality of module monitoring boards of the second battery string are in communication with a second battery string control unit.

146. The electric vehicle of Claim 145, wherein the first battery string control unit is configured to control the state of the first switch, wherein the second battery string control unit is configured to control the state of the second switch.

147. The electric vehicle of Claim 145, wherein the first battery string control unit and the second battery control unit are in communication with a battery pack controller.

148. The electric vehicle of Claim 141, wherein the battery management system comprises a battery pack controller configured to disconnect the first and second switches.

149. An energy storage system comprising:

a plurality of modules, each module including:

a plurality of cylindrical rechargeable lithium-ion cells, the rechargeable cells each having a first end and a second end, the first end distal from the second end, an anode terminal and a cathode terminal being disposed at the first end, and a vent disposed at the second end;

a current carrier electrically coupled to the plurality of cells, the cathode terminal of each cell being welded to a respective positive contact of the current carrier, the anode terminal of each cell being welded to a respective negative contact of the current carrier, the negative contact including a fuse;

a blast plate disposed substantially parallel to the current carrier such that the plurality of cells are disposed in-between the current carrier and the blast plate, the blast plate being closer to the second end of the plurality of cells than to the first end;

an enclosure, the plurality of cells, current carrier, and blast plate being disposed inside the enclosure, the enclosure including a main power connector, coolant input port, and coolant output port, the main power connector being electrically coupled to the current carrier; and

a coolant, the coolant being pumped into the enclosure through the input port and out of the enclosure through an output port such that each of the plurality of cells is at approximately the same predetermined temperature; and

a tray, the plurality of modules being disposed in the tray, the tray including a positive bus bar and a negative bus bar, the positive bus bar being electrically coupled to a main power connector associated with a first module of the plurality of modules and the negative bus bar being electrically coupled to a main power connector associated with a second module of the plurality of modules.