WO2010076767A1

WO2010076767A1 - Modular battery management system

Info

Publication number: WO2010076767A1
Application number: PCT/IB2009/055990
Authority: WO
Inventors: Jes Erik Thomsen
Original assignee: Lithium Balance A/S
Priority date: 2008-12-30
Filing date: 2009-12-30
Publication date: 2010-07-08

Abstract

The invention relates to a battery module comprising an enclosure, a switch board made of insulating material, and a stack of a specific number of flat batteries located within said enclosure, each battery having a shallow side surface being positioned juxtaposed said switch board, said side surface defining two separate flexible flat contacts of thin metal sheet extending a particular distance through a specific gap pair of said switch board, said particular distance smaller than said spacing between said gap pairs, said flat contact being bent in said transversal direction juxtaposed said switch board in either an upwardly direction or a downwardly direction, a number of metallic plates being clamped between said gaps and electrically connecting said flat contacts extending from two adjacent gaps of different gap pairs, said metallic plates being optionally interconnected, for achieving alternatively a series connection, a parallel connection or a combination between said batteries, and two terminal plates being electrically connected to the flat contact of the first and the last battery of said battery. Specifically said flat batteries can be lithium batteries.

Description

MODULAR BATTERY MANAGEMENT SYSTEM

TECHNICAL FIELD

The invention relates to battery cell packs, more specifically to battery cell packs comprising lithium battery cells and still more specifically lithium battery cell packs for use in automobiles

BACKGROUND OF THE INVENTION

Typically, battery cell packs are used in electrical equipment such as electrical cars Modular Battery Management Systems may be used for controlling the current and voltage of such battery packs both during charging and discharging.

SUMMARY OF THE INVENTION

According to the present invention there is provided a switchboard, a Local Monitoring Unit (LMU) and a modular battery management system (BMCU) for controlling the input and output voltages and currents of the battery pack.

More specifically there is according to the invention provided a battery module including: an enclosure, a switch board made of insulating material, said switch board defining a first end, a second end, a longitudinal direction between said ends and a transversal direction, said switch board further defining a specific number of gap pairs, each of said gap pair defining two separate, thin gaps located at said first and second end, respectively, and extending in said longitudinal direction, said gap pairs being arranged in said transversal direction having an equal spacing between themselves, and a stack of a specific number of flat batteries located within said enclosure, each battery having a shallow side surface being positioned juxtaposed said switch board, said side surface defining two separate flexible flat contacts of thin metal sheet extending a particular distance through a specific gap pair of said switch board, said particular distance smaller than said spacing between said gap pairs, said flat contact being bent in said transversal direction juxtaposed said switch board in either an upwardly direction or a downwardly direction, a number of metallic plates being clamped between said gaps and electrically connecting said flat contacts extending from two adjacent gaps of different gap pairs, said metallic plates being optionally interconnected, for achieving alternatively a series connection, a parallel connection or a combination between said batteries, and two terminal plates being electrically connected to the flat contact of the first and the last battery of said battery.

Specifically, said flat batteries are lithium batteries

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood with reference to the following detailed description of non-limiting embodiments of the invention as shown in the figures, in which:

fig 1 is a perspective view of a battery cell module; fig 2 is a enclosure, fig 3-5 is a battery cell module; fig 6 is a perspective view of the battery cell module; fig 7 is a perspective side view of the battery cell module; fig 8 is the circuit board comprising a LMU (Local Monitoring Unit); fig 9 is the BMCU {Modular Battery Management System); fig 10 is a schematic view of the BMCU; and fig 11 is a flow chart view. DETAILED DESCRIPTION OF THE INVENTION

In the following there are described some exemplary embodiments of a modular battery eel! management system according to the present invention.

Fig 1 shows a perspective view of a battery cell module 10 according to an embodiment of the present invention. The battery cell module 10 comprises an enclosure 12 constituting a box-shaped housing of plastic, metal or any similar material which is rigid enough for accommodating a battery cell pack inside the enclosure 12, (The battery cell pack is not shown here, but will be described later ) The enclosure 12 should as well be able to protect the battery cell pack of any shocks etc from the outside and be able of transporting any residua! heat from the interior of the enclosure 12 to the outside The enclosure 12 defines a rectangular opening, which is covered by a front piate 14. The front plate is removable for accessing the interior of the enclosure 12, and defines an upper side 18, a lower side 18', a right side 18" and a left side 18'" The sides 18 seals against the opening of the enclosure 12, thereby preventing access to the interior of the enclosure 12 The front plate 14 is fixated to the enclosure 12 by a pair of screws 16 16', which are accommodated in the comers defined by the lower side 18' and the right side 18", and the upper side 18 and the left side 18'", respectively. The battery cell module 10 further comprises a plus terminal 20 and a minus terminal 20' constituting metallic knob electrodes extending from the interior of the enclosure 12 through the front plate The front plate 14 defines apertures for allowing the terminals 20 20' to extend through the front plate 14 of the battery cell module 10. The terminals 18 and 20 are positioned at the opposite corners of the front plate 14 defined by the upper side 18 and the right side 18", and the lower side 18 and the left side 18'", respectively.

Fig. 2a shows a top view of the enclosure 12 of the battery cell module 10, The enclosure 12 defines an enclosure length of 244 mm and a width 24 of 228 mm. The electrodes 20 and 20 protrude 15¹/z mm from the front plate 14, Thus, the total length of the battery cell module 10 is 259Y₂ mm. It is understood both here and throughout the entire specification that numerical values are only mentioned and shown in the drawings as non-limiting examples Fig. 2b shows a front view of the battery cell module 10 The front plate 14 and thereby the enclosure 12 defines a height of 120 mm. The width of the front plate corresponds to the width of the enclosure, i.e. 228 mm. The first screw 16 is located at the lower right corner defined by the lower side 18' and the right side 18" of the front plate 14, 20 mm above the lower side 18' and 17% mm from the right side 18". The second screw 16' is located at the upper left corner defined by the upper side 18 and the left side 18'" of the front piate 14, 20 mm below the upper side 18 and 1734 mm from the left side 18'" The plus terminal 20 is located at the upper right corner defined by the upper side 18 and the right side 18" of the front plate, 38 mm above the upper side 18 of the front plate 14 and 15 mm from the right side 18" of the front plate 14. The minus terminal 20' is located at the lower left corner defined by the lower side 18' and the left side 18'" of the front plate located 38 mm above the lower side 18' of the front plate 14 and 15 mm from the left side 18'" of the front plate 14. All measures are in relation the centre point of the terminals 18 and 20 and screws 16

Fig. 3 shows the battery cell module 10 when the front plate has been removed from the enclosure 12. A circuit board 22 is located behind the front plate between the terminals 20 20' and screws 16 16' within the enclosure. The circuit board 22 is located above a switchboard 24. The circuit board 22 constitutes a control and monitoring unit for controlling the charging and discharging of the battery cell as well as monitoring the status of the battery cells. The features of the circuit board will be further described in figs 8-1 1.

Fig. 4 shows the battery eel! module 10 when the circuit board 22 has been removed. By removing the circuit board 22, the switchboard 24 is made visible. The switchboard 24 comprises a plurality of elongated gaps 34. The gaps 34 are organised in pairs constituting two columns and eight rows having identical spacing between both columns and between each of the rows The gaps 34 are used for accommodating flat contacts from a cell pack comprising eight flat battery cells located on the opposite side of the switchboard 24 within the enclosure 12 The flat contacts protrude outwardly through the switch board 24 a distance less than the spacing between two subsequent rows The flat battery cells are stacked on top of each other with alternating polarity, i e in each coiumn the polarity is alternating between plus polarity and minus polarity. The flat contacts of the flat battery cells are flexible and are bent towards the outwardly facing surface of the switchboard 24, The flat contacts may be bent either upwardly or downwardly depending on the configuration of the switchboard 24. Contact plates 36 are provided for electrically connecting two adjacent flat contacts of the same column The contact plates 36 have holes 38 which correspond to holes 40 in the switchboard 24 so that the contact plates 36 may be fastened onto the switchboard 24 in the spacing between two adjacent gaps 34 The holes 40 are located between the gaps 34 and comprise three holes for each spacing between two adjacent gaps 24

In the present configuration, the plus terminal 20 is connected to the first plate 36^!, where it contacts the plus electrode of the first battery cell having a flat contact which is bent downwards. The minus electrode of the first battery cell is as well bent downwards and in contact with the second plate 36" on the same row, but different column as the plus contact of the first battery cell. The plus contact of the second battery cell is as well connected to the second plate 36" by being bent upwards. The minus contact of the second battery cell is bent downwards and contacting the third plate 36^m. The third plate 36¹" is as well contacted to the plus contact of the third battery cell The minus contact of the third battery cell is connected to the plus contact of the fourth battery cell via the plate 36^!V, The fifth, sixth, sevent and eight battery cell are connected according to the above principle by the plates 36^IV to 36^IX. The present configuration will thus be forming a series connection of the eight battery celis within the battery cell module 10

Fig, 5 shows a battery cell module 10 as shown in Fig. 4, however having a switchboard configured as series connected pair wise parallel connected battery cells. This is achieved by orienting the battery celis in pairs having the same orientation and the pairs in turn being oriented with alternating orientation Further, both the plus electrodes of the first and second battery cell are connected to the first plate 36¹ by bending the plus electrode of the first battery cell downwards and the plus electrode of the second battery cell upwards. The second plate 36" and the fourth plate 36^[V are interconnected, thereby effectively forming a double plate designated reference numeral 42 Thereby, the minus electrodes of the first and second battery cell are connected to the plus electrodes of the third and fourth battery cell. The other battery ceils are connected likewise, thereby forming a pair wise parallel connection providing a total voltage between the plus and minus terminals 20 20' equal to half the voltage of a series connected configuration as shown in Fig. 4.

Fig 6 shows a perspective view of the battery cell module 10 when the enclosure has been removed. By removing the enclosure, the pack of eight flat battery cells 44 is revealed The fiat battery cells 44 are stacked on top of each other to fit inside the enclosure (not shown here). The flat battery cells 44 constitute lithium battery cells. Each flat battery cell has a plus contact and a minus contact constituting flat contacts or flat electrodes. The flat contacts are fed through the gaps 34 of the switchboard 24 and bent either upwards or downward onto the switchboard 24 The plates 36 are providing electrical contact between two adjacent battery cell contacts, protruding from two adjacent gaps 34. Where no plate is present in the spacing between two adjacent gaps 34, the respective battery cell contacts are not conntected, and consequently isolated in relation to each other

Fig 6b shows a side view of the battery cell module 10 when the enclosure has been removed.

Fig 7 shows a perspective side view of the battery cell module 10 as shown in Fig. 6. The battery cell pack comprise a stack of eight juxtaposed mounted lithium battery cells 44 It is clearly shown how the flat contacts 46 of the battery cells 44 penetrate the switchboard 24 at the gaps 34 and are fastened by the plates 36, The plates are fixated to the switchboard 24 by screws.

Fig 8 shows the circuit board 22 constituting a Local Monitoring Unit (LMU). The LMU is a component of a Modular Battery Management System. A number of LMU's work together with a Battery Management Control Unit (BMCU)₁ shown in fig 10-11 , to form the complete Modular Battery Management System. The LMU precisely monitors the voltages and temperatures of up to 8 Lithium battery cells and actively balances the battery ceils to keep the battery cell pack in an optimal condition Further LMU's and battery cell packs can be added to the system, which makes it possible to monitor high-voltage battery packs of up to 160 battery cells.

Some of the features of the LMU include.

• Monitoring of up to 8 Lithium Battery cell Voltages

• Active Battery cell Balancing

• External Battery cell Temperature Measurement

• Local Board Temperature Measurement

• Local isolated Communication with BMCU

• Automatic Addressing of LMU's

• Standard Euro Card Format ( 100^* 160mm)

Electrical specification of the LMU:

Fig 9 shows a BMCU The BMCU is a component of the Modular Battery Management System where a number of LMU's work together with a BMCU to form the complete Modular Battery Management System The BMCU communicates with the Modular Battery Management Systems main computer via a CAN bus and controls the complete battery pack during charge and discharge Current is measured with an off-board current shunt resistor and contro! of an off-board POWER MOSFET or !GBT is available for overload and short-circuits protection

Some of the features of the LMU include:

Controlling of up to 32 LMU's

Controlling of Active Battery cell Balancing

Local Isolated Communication with LMU's

Automatic Addressing of LMU's

CAN-bus Interface

Isolated Diagnostics Interface (RS232)

7 General Purpose lnpuls

8 Genera! Purpose Outputs

Controling of Charge Process (Voltage and Current)

Isolation Fault Detection

Current Measurement

Standard Euro Card Format {100^*160mm)

Fig 10 shows a schematic view of the BMCU. The Modular Battery Management system comprises a scalable number of battery cells The battery cells are arranged in series connected modules of 3 to 8 cells, each monitored and balanced by a Local Monitoring Unit (LMU). The Battery Master Control Unit (BMCU) collects all battery cell data from the LMU's, measures the charge/discharge currents and controls a switch unit. The BMCU also controls the internal cooling fan and communicates externally via CAN and diagnostics serial interfaces, Additionally the BMCU controls the charging process and has various inputs and outputs to interface with the user applications.

Each cell pack is connected to an LMU. The LMU measures voltage and temperature and controls cell balancing. A number of LMU's are connected to the BMCU and communicates with the BMCU by serial communication. The cell packs are connected in series to a plus terminal constituting contacts for +LOAD₁ +LOAD Pre-Charge and +Charger, and a minus terminal constituting contacts for -Charger and a -LOAD, The BMCU further has interfaces for Cooling fan control, CAN communication, Diagnostics communication, Charger control, Fuel gauge, Analog outputs, Analog inputs, Digital outputs and Digital inputs.

Fig 1 1 shows a flow chart view describing the different system modes of the BMCU. The BMCU can be in any of the following modes:

• Charge Mode: In the charge mode, the charge switch is on, the charger control is on, the cell balancing is active, and the overcharge and temperature protection is active ,

• Discharge Mode. In the discharge mode, the discharge switch is on and the following protection circuits are activated: overload, short circuit, deep discharge and temperature.

• Idle Mode: In idle mode all switches are off and the communication is on. • Sleep Mode: The BMCU enters sleep mode after a period of no activity In sleep mode, all switches are off, resulting in min. power consumption

• Error Mode: In error mode, all switches are off and error is indicated.

• Regenerative Breaking. ( regenerative breaking is included in Discharge Mode)

It is shown in the figure how exchanges between the different system modes shall be. Accordingly, from idle mode, the BMCU may enter sleep mode after x minutes of no activity, charging mode by connecting the charger, or discharging mode by "ignition on". From the sleep mode the BMCU may enter the idle mode by "ignition on", by connecting the charger or by CAN (Controller Area Network) communication. From the charge mode, the system may enter idle mode when charging is complete or the charger is disconnected, and the error mode by overcharge or unsuitable temperature of the battery cells. From the discharge mode, the system may enter the idle mode by ignition off and the error mode by overload, short circuit, deep discharge or unsuitable temperature of the battery cells From the error mode, the system may enter the idle mode by charger disconnected and "ignition off, "ignition on/off may be controlld by the user by e.g pressing a button or the like

Claims

1. A battery module including: an enclosure, a switch board made of insulating material, said switch board defining a first end, a second end, a longitudinal direction between said ends and a transversa! direction, said switch board further defining a specific number of gap pairs, each of said gap pair defining two separate, thin gaps located at said first and second end, respectively, and extending in said longitudinal direction, said gap pairs being arranged in said transversal direction having an equal spacing between themselves, and a stack of a specific number of flat batteries located within said enclosure, each battery having a shallow side surface being positioned juxtaposed said switch board, said side surface defining two separate flexible flat contacts of thin metal sheet extending a particular distance through a specific gap pair of said switch board, said particular distance smaller than said spacing between said gap pairs, said flat contact being bent in said transversal direction juxtaposed said switch board in either an upwardly direction or a downwardly direction, a number of metallic plates being clamped between said gaps and electrically connecting said flat contacts extending from two adjacent gaps of different gap pairs, said metallic plates being optionally interconnected, for achieving alternatively a series connection, a parallel connection or a combination between said batteries, and two terminal plates being electrically connected to the fiat contact of the first and the last battery of said battery,

2 A battery module according to claim 1 , wherein said fiat batteries are lithium batteries,

3. A battery module according to claim 1 or 2, furthermore comprising a Local Monitoring Unit (LMU) and a modular battery management system (BMCU) for controlling the input and output voltages and currents of the battery pack.