GB2625519A - Battery assembly for vehicle - Google Patents

Battery assembly for vehicle Download PDF

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Publication number
GB2625519A
GB2625519A GB2218942.7A GB202218942A GB2625519A GB 2625519 A GB2625519 A GB 2625519A GB 202218942 A GB202218942 A GB 202218942A GB 2625519 A GB2625519 A GB 2625519A
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GB
United Kingdom
Prior art keywords
cell
sub
assembly
segment
electrical
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
GB2218942.7A
Other versions
GB202218942D0 (en
Inventor
Villaca Koch Dutra Marcelo
Mcmanus Charles
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Jaguar Land Rover Ltd
Original Assignee
Jaguar Land Rover Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Jaguar Land Rover Ltd filed Critical Jaguar Land Rover Ltd
Priority to GB2218942.7A priority Critical patent/GB2625519A/en
Publication of GB202218942D0 publication Critical patent/GB202218942D0/en
Priority to PCT/EP2023/085873 priority patent/WO2024126711A1/en
Publication of GB2625519A publication Critical patent/GB2625519A/en
Pending legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H01M50/507—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing comprising an arrangement of two or more busbars within a container structure, e.g. busbar modules
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H01M50/207—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape
    • H01M50/209—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for prismatic or rectangular cells
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L50/00—Electric propulsion with power supplied within the vehicle
    • B60L50/50—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells
    • B60L50/60—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells using power supplied by batteries
    • B60L50/64—Constructional details of batteries specially adapted for electric vehicles
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/249—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders specially adapted for aircraft or vehicles, e.g. cars or trains
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/296—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders characterised by terminals of battery packs
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H01M50/503—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the shape of the interconnectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H01M50/509—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the type of connection, e.g. mixed connections
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H01M50/509—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the type of connection, e.g. mixed connections
    • H01M50/51—Connection only in series
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
    • H01M50/514—Methods for interconnecting adjacent batteries or cells
    • H01M50/516—Methods for interconnecting adjacent batteries or cells by welding, soldering or brazing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/103—Primary casings; Jackets or wrappings characterised by their shape or physical structure prismatic or rectangular
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/543—Terminals
    • H01M50/547—Terminals characterised by the disposition of the terminals on the cells
    • H01M50/548—Terminals characterised by the disposition of the terminals on the cells on opposite sides of the cell
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Power Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Battery Mounting, Suspending (AREA)
  • Connection Of Batteries Or Terminals (AREA)

Abstract

Aspects of the present invention relate to a traction battery assembly for a vehicle, to a battery pack, to a vehicle and to a method of electrically connecting cells. The battery assembly comprises a plurality of battery sub-assemblies (610, 620, 30, 640). Each sub-assembly comprises a respective plurality of electrical cells (100), each electrical cell comprising a first cell terminal situated on a first end face (110), a second cell terminal situated on a second end face (120), an upper face (130), a lower face (140), and two opposing side faces (150), each of the upper face, lower face and opposing side faces extending between the first end face (110) and the second end face (120). The plurality of electrical cells (100) of each sub-assembly are stacked side face to side face extending along a first dimension. The plurality of sub-assemblies (610, 620, 630, 640) are stacked in a second dimension perpendicular to the first dimension, extending from a first sub-assembly (610) to a final sub-assembly (640). Each sub-assembly is divided along the first dimension into at least a first segment (600-a) and a second segment (600-b), wherein the cells within the first segment are electrically connected and wherein the cells within the second segment are electrically connected. A respective first busbar arrangement (650-a) is disposed between the first segment (600-a) of each pair of neighbouring sub-assemblies to electrically connect the first segment of each pair of neighbouring sub-assemblies in series. A respective second busbar arrangement (650-b) is disposed between the second segment (600-b) of each pair of neighbouring sub-assemblies to electrically connect the second segment of each pair of neighbouring sub-assemblies in series. The first segment (600-a) and the second segment (600-b) of the final sub-assembly (640) are connected together in series. Thus, the segments of the traction battery assembly (600) are connected in series along each first segment (600-a) from the first segment of the first sub-assembly (610) to the first segment of the final sub-assembly (640), and back along each second segment (600-b) from the second segment of the final sub-assembly (640) to the second segment of the first sub-assembly (610).

Description

BATTERY ASSEMBLY FOR VEHICLE
TECHNICAL FIELD
The present disclosure relates to a battery assembly, in particular a traction battery assembly, for a vehicle.
Aspects of the invention relate to traction battery assemblies, to battery packs, and to methods of connecting electrical cells in a traction battery assembly, as well as to an electric vehicle incorporating the same.
BACKGROUND
A traction battery assembly comprises a plurality of electrical cells connected to provide power to an electric motor of an electric vehicle (EV), for example a battery electric vehicle (BEV) or hybrid electric vehicle (HEV).
The electrical cells within a traction battery assembly may be arranged in modules or sub-assemblies. The electrical cells are electrically connected together via a busbar arrangement including cell busbars to connect the cells within a module or sub-assembly, and pack busbars to connect the modules or sub-assemblies together. The busbar arrangement takes up space within the traction battery assembly, thus reducing the energy density of the battery. Furthermore, the longer the busbars are within the busbar arrangement, the more energy loss from resistance is produced and the higher the associated material cost of the busbars.
It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.
SUMMARY OF THE INVENTION
Aspects and embodiments of the invention provide a traction battery assembly, a battery pack and a method of connecting electrical cells as claimed in the appended claims, as well as an electric vehicle incorporating such traction battery pack.
According to an aspect of the present invention there is provided a traction battery assembly for a vehicle comprising at least: a first electrical cell and a second electrical cell, each of the first and second electrical cell comprising a first cell terminal situated on a first end face, a second cell terminal situated on a second end face, an upper face, a lower face, and two opposing side faces, each of the upper face, lower face and opposing side faces extending between the first end face and the second end face; and a busbar arrangement for electrically connecting the first electrical cell to the second electrical cell, the busbar arrangement comprising: a first cell busbar connected to the first cell terminal of the first electrical cell, wherein the first cell busbar extends from the first end face of the first electrical cell and is entirely located between a plane of the upper face of the first electrical cell and a plane of the lower face of the first electrical cell; and a second cell busbar connected to the second cell terminal of the second electrical cell, wherein the second cell busbar extends from the second end face of the second electrical cell and is entirely located between a plane of the upper face of the second electrical cell and a plane of the lower face of the second electrical cell, wherein the first cell busbar is welded directly to the second cell busbar to provide an electrical connection between the first cell terminal of the first electrical cell and the second cell terminal of the second electrical cell.
Advantageously, welding the cell busbars together directly negates the need for a third connecting busbar as is typical in pack busbar assemblies. Furthermore, entirely locating the first and second cell busbar between the upper and lower face of each cell and welding these busbars together means that the entire busbar arrangement is bounded between the upper plane and the lower plane of each cell. In some embodiments, the first electrical cell and second electrical cell are aligned such that the upper face of each cell is coplanar and the lower face of each cell is coplanar. Thus, the electrical connection provided by the busbar assembly can be entirely situated between the upper and lower faces of the assembly defined by the cell geometry, without adding any height to the assembly. Therefore, the busbar arrangement can be routed entirely internal to the battery assembly. This increases the space efficiency of the assembly, as the busbars do not need to invade a or extend above the electrical cells in z direction, thus utilising this type of busbar arrangement can maximise the number of cells situated in the available space.
In some embodiments, the first cell busbar is entirely disposed between opposing planes defined by the opposing side faces of the first cell, and the second cell busbar is entirely disposed between opposing planes defined by the opposing side faces of the second cell, further improving the space efficiency of the arrangement.
Optionally, the first cell terminal is a positive terminal, and the second cell terminal is a negative terminal. Alternatively, the first cell terminal is a negative terminal, and the second cell terminal is a positive terminal.
The first cell and second cell may each be pouch cells or prismatic cells.
Optionally, one of the first cell busbar and the second cell busbar is a flexible laminated busbar. Beneficially, providing flexibility via lamination for one busbar means that the busbar connection is robust to vehicle vibration, even when the busbars are very short. Retaining one cell busbar as inflexible or rigid means that the rigid busbar can support the busbar arrangement during assembly, reducing the risk of a short circuit.
In some embodiments, each of the first cell busbar and second cell busbar are formed from aluminium. Use of aluminium can provide a beneficial reduction in weight across the battery assembly. Alternatively, each of the first cell busbar and second cell busbar may be formed from another material such as copper. The first cell busbar may be laser welded to the first cell terminal of the first electrical cell, and the second cell busbar may be laser welded to the second cell terminal of the second electrical cell.
Optionally, each of the first cell busbar and second cell busbar is an L-shaped busbar comprising a terminal planar portion welded to the respective cell terminal and a protruding planar portion substantially perpendicular to the terminal planar portion; and the protruding planar portion of the first cell busbar is welded along an overlap to the protruding planar portion of the second cell busbar. Advantageously, the overlapping protrusion of each L shape provides a strong conductive join which provides structural integrity to the busbar arrangement. Optionally, there is a ratio of at least 1.5 between the thickness of the protruding planar portion of first cell busbar to the thickness of the protruding planar portion of second cell busbar in order to improve the quality of the welded overlap. Optionally, the overlap has a minimum length which is at least 5 times a thickness of thinnest busbar. For example, if a thinnest busbar is 4mm thick the protruding planar portions should be overlapped by at least 20mm. This provides a reliable current flow through the busbar arrangement.
Optionally, the assembly comprises a first sub-assembly of electrical cells including the first electrical cell, and a second sub-assembly of electrical cells including the second electrical cell, wherein the first sub-assembly and the second sub-assembly are electrically connected via the busbar arrangement. Thus, beneficially different sub-assemblies or modules within a vehicle battery can be electrically connected by the busbar arrangement entirely between cells without protruding above or to the side of the assembly.
Optionally, the first sub-assembly comprises a first plurality of cells stacked side face to side face extending along a first dimension; and the second sub-assembly comprises a second plurality of cells stacked side face to side face extending along the first dimension. The first electrical cell may be disposed between a first end cell and a second end cell of the first sub-assembly, and the second electrical cell may be disposed between a first end cell and a second end cell of the second sub-assembly. Thus, the busbar arrangement may be used to connect sub-assemblies in the middle of the battery assembly and thus be wholly internal to the assembly.
Optionally, the first sub-assembly and the second sub-assembly are stacked in a second dimension perpendicular to the first dimension, wherein the first cell and the second cell are aligned in the second dimension. Beneficially, this arrangement minimises required length of busbars as the sub-assemblies are connected via adjacent terminals, thus minimising the resistance and the cost of busbar manufacture.
Optionally, the traction battery assembly comprises a plurality of sub-assemblies including the first subassembly and the second sub-assembly, each sub-assembly comprising a respective plurality of electrical cells stacked side face to side face extending along the first dimension, wherein the plurality of sub-assemblies are stacked in the second dimension extending from the first sub-assembly to a final sub-assembly, and wherein: each sub-assembly is divided along the first dimension into at least a first segment and a second segment, wherein the cells of each of the first segment and second segment are electrically connected; a respective first busbar arrangement is disposed between the first segment of each pair of neighbouring subassemblies to electrically connect the first segment of each pair of neighbouring sub-assemblies in series; a respective second busbar arrangement is disposed between the second segment of each pair of neighbouring sub-assemblies to electrically connect the second segment of each pair of neighbouring sub-assemblies in series; and the first segment and the second segment of the final sub-assembly are connected together in series; such that the segments of the traction battery assembly are connected in series along each first segment from the first segment of the first sub-assembly to the first segment of the final sub-assembly, and back along each second segment from the second segment of the final sub-assembly to the second segment of the first sub-assembly. Beneficially, this arrangement of cells provides a traction battery assembly without the need for any long busbars.
Optionally, wherein each of the respective first and second busbar arrangements for connecting a respective pair of sub-assemblies comprises a first cell busbar and a second cell busbar, wherein the first cell busbar is welded directly to the second cell busbar. Optionally each of the respective first and second busbar arrangements are entirely located between an upper plane of the respective pair of sub-assemblies and a lower plane of the respective pair of sub-assemblies. Thus, the busbar arrangements may all be located entirely between cells without extending above or below the assembly.
Optionally, each segment comprises one or more sub-segments, each sub-segment comprising a plurality of electrical cells connected in parallel, wherein the one or more sub-segments are connected in series. For example, each sub-segment may comprise a pair of electrical cells.
Optionally, the traction battery assembly comprises a first battery terminal on the first segment of the first sub-assembly and a second battery terminal on the second segment of the first sub-assembly, wherein the first and second battery terminals are for connecting the traction battery assembly to a traction motor of the vehicle.
According to another aspect there is provided a battery pack comprising: a first traction battery assembly according to the above aspect, a second traction battery assembly according to the above aspect, and a switching mechanism arranged to selectively connect the first traction battery assembly with the second traction battery assembly in series or parallel. Optionally, the second traction battery assembly is stacked together with the first traction battery assembly along a third dimension perpendicular to the first dimension and second dimension. Optionally, the battery pack further comprises a battery control module operatively connected to the switching mechanism, wherein the battery control module is arranged to control the switching mechanism to switch between the series and parallel connections.
According to another aspect, there is provided a vehicle comprising a traction battery assembly or a battery pack according to the above aspects.
According to another aspect, there is provided a method of connecting electrical cells within a traction battery assembly, the method comprising: providing a first electrical cell and a second electrical cell, each of the first and second electrical cell comprising a first cell terminal situated on a first end face, a second cell terminal situated on a second end face, an upper face, a lower face, and two opposing side faces, each of the upper face, lower face and opposing side faces extending between the first end face and the second end face; and electrically connecting the first electrical cell to the second electrical cell, by: connecting a first cell busbar connected to the first cell terminal of the first electrical cell, such that the first cell busbar extends from the first end face of the first electrical cell and is entirely located between a plane of the upper face of the first electrical cell and a plane of the lower face of the first electrical cell; connecting a second cell busbar to the second cell terminal of the second electrical cell, such that the second cell busbar extends from the second end face of the second electrical cell and is entirely located between a plane of the upper face of the second electrical cell and a plane of the lower face of the second electrical cell; and welding the first cell busbar directly to the second cell busbar to provide an electrical connection between the first cell terminal of the first electrical cell and the second cell terminal of the second electrical cell.
According to another aspect of the present invention there is provided a traction battery assembly for a vehicle comprising at least: a plurality of battery sub-assemblies, each sub-assembly comprising a respective plurality of electrical cells, each electrical cell comprising a first cell terminal situated on a first end face, a second cell terminal situated on a second end face, an upper face, a lower face, and two opposing side faces, each of the upper face, lower face and opposing side faces extending between the first end face and the second end face, wherein the plurality of electrical cells of each sub-assembly are stacked side face to side face extending along a first dimension, and wherein: the plurality of sub-assemblies are stacked in a second dimension perpendicular to the first dimension, extending from a first sub-assembly to a final sub-assembly, and each sub-assembly is divided along the first dimension into at least a first segment and a second segment, wherein the cells within the first segment are electrically connected and wherein the cells within the second segment are electrically connected; a respective first busbar arrangement disposed between the first segment of each pair of neighbouring sub-assemblies to electrically connect the first segment of each pair of neighbouring sub-assemblies in series; a respective second busbar arrangement disposed between the second segment of each pair of neighbouring sub-assemblies to electrically connect the second segment of each pair of neighbouring sub-assemblies in series; wherein the first segment and the second segment of the final sub-assembly are connected together in series, such that the segments of the traction battery assembly are connected in series along each first segment from the first segment of the first sub-assembly to the first segment of the final sub-assembly, and back along each second segment from the second segment of the final sub-assembly to the second segment of the first sub-assembly. Advantageously, the assembly provides a compact battery arrangement which only requires short busbars between neighbouring sub-assemblies and no long busbars. Optionally, the electrical cells are pouch cells or prismatic cells Optionally, the traction battery assembly comprises a first battery terminal on the first segment of the first subassembly and a second battery terminal on the second segment of the first sub-assembly, wherein the first and second battery terminals are for connecting the traction battery assembly to a traction motor of the vehicle. Advantageously, because the cells are connected in an "out and back" manner, connecting terminals of the arrangement can be located at a same side of the arrangement (on the first sub-assembly) facilitating short end busbar connections to the traction motor.
Optionally, each respective first and second busbar arrangement electrically connects a first electrical cell of a respective first sub-assembly to a second electrical cell of a respective neighbouring second sub-assembly, each first and second busbar arrangement comprising: a first cell busbar connected to the first cell terminal of the first electrical cell; and a second cell busbar connected to the second cell terminal of the second electrical cell, wherein the first cell busbar is welded directly to the second cell busbar to provide an electrical connection between the first cell terminal of the first electrical cell and the second cell terminal of the second electrical cell. Advantageously, welding the cell busbars together directly negates need for a third connecting busbar to be provided between sub-assemblies. Optionally, the first cell terminal is a positive terminal, and second cell terminal is a negative terminal, or vice versa. Optionally, each of the first cell busbar and second cell busbar are formed from aluminium. Alternatively, each of the first cell busbar and second cell busbar may be formed from copper. Optionally, the first cell busbar is laser welded to the first cell terminal of the first electrical cell, and the second cell busbar is laser welded to the second cell terminal of the second electrical cell.
Optionally, for each first and second busbar arrangement: the first cell busbar extends from the first end face of the first electrical cell and is entirely located between a plane of the upper face of the first electrical cell and a plane of the lower face of the first electrical cell; and the second cell busbar extends from the second end face of the second electrical cell and is entirely located between a plane of the upper face of the second electrical cell and a plane of the lower face of the second electrical cell. That is, the first and second cell busbar are each bounded between the upper plane and the lower plane of each cell. Advantageously, the electrical connection can be entirely situated between the cells and therefore, the connecting busbars can be contained entirely within the pack. This increases the space efficiency of pack, as the busbars do not need to invade side vehicle crash plane or extend above the cells in z direction, thus the number of cells can be maximised in an available space. Optionally, the first cell busbar is entirely disposed between the opposing planes defined by the opposing side faces of the first cell.
Optionally, in each respective first and second busbar arrangement, one of the first cell busbar and the second cell busbar is a flexible laminated busbar. Advantageously, providing flexibility via lamination for one busbar means that the busbar connection is robust to vehicle vibration, even when the busbars are very short.
Retaining one rigid or inflexible busbar means that the busbar connection is supported during assembly, reducing a risk of short circuit.
Optionally, in each respective first and second busbar arrangement: each of the first cell busbar and second cell busbar is an L-shaped busbar comprising a terminal planar portion welded to the respective cell terminal and a protruding planar portion substantially perpendicular to the terminal planar portion; and the protruding planar portion of the first cell busbar is welded along an overlap to the protruding planar portion of the second cell busbar. Advantageously, the overlapping protrusion of each L shape provides a strong conductive join. Optionally, there is a ratio of at least 1.5 between a thickness of the protruding planar portion of the first cell busbar to the thickness of the protruding planar portion of the second cell busbar. Optionally, there is a minimum overlap of at least 5 times the thickness of the thinnest busbar.
Optionally, for at least one of the respective first or second busbar arrangements within the assembly: the first electrical cell is disposed between a first end cell and a second end cell of the respective first sub-assembly, and the second electrical cell is disposed between a first end cell and a second end cell of the respective second neighbouring sub-assembly. Thus, the busbar arrangement may be used to connect sub-assemblies in the middle of the battery pack without extending beyond the periphery of the pack. Optionally, the first cell and the second cell are aligned in the second dimension. Beneficially, this arrangement minimises a required length of the busbars as the sub-assemblies are connected via adjacent terminals.
Optionally, each segment comprises one or more sub-segments, each sub-segment comprising two or more electrical cells connected in parallel, wherein the one or more sub-segments are connected in series within the segment. Optionally, each sub-segment comprises a pair of electrical cells.
According to another aspect there is provided a battery pack comprising: a first traction battery assembly according to the aspect above, a second traction battery assembly according to the aspect above, and a switching mechanism arranged to selectively electrically conned the first traction battery assembly with the second traction battery assembly in series or parallel. Optionally, the second traction battery assembly is stacked together with the first traction battery assembly along a third dimension perpendicular to the first dimension and second dimension. Optionally, the battery pack further comprises a battery control module operatively connected to the switching mechanism, wherein the battery control module is arranged to control the switching mechanism to switch between the series and parallel connections.
According to another aspect there is provided a vehicle comprising a traction battery assembly or a battery pack according to the above aspects.
According to another aspect there is provided a method of connecting electrical cells within a traction battery assembly, the method comprising: providing a plurality of electrical cells, each electrical cell comprising a first cell terminal situated on a first end face, a second cell terminal situated on a second end face, an upper face, a lower face, and two opposing side faces, each of the upper face, lower face and opposing side faces extending between the first end face and the second end face, constructing a plurality of sub-assemblies, wherein constructing each sub-assembly comprises stacking a plurality of the electrical cells side face to side face extending along a first dimension, dividing each sub-assembly along the first dimension into at least a first segment and a second segment, electrically connecting the cells of the first segment, and electrically connecting the cells of the second segment; stacking the plurality of sub-assemblies in a second dimension perpendicular to the first dimension, extending from a first sub-assembly to a final sub-assembly; electrically connecting the first segment of each pair of neighbouring sub-assemblies in series by providing a respective first busbar arrangement disposed between the first segment of each pair of neighbouring sub-assemblies; electrically connecting the second segment of each pair of neighbouring sub-assemblies in series by providing a respective second busbar arrangement disposed between the second segment of each pair of neighbouring sub-assemblies; and electrically connecting the first segment and the second segment of the final sub-assembly in series, such that the segments of the traction battery assembly are connected in series along each first segment from the first segment of the first sub-assembly to the first segment of the final subassembly, and back along each second segment from the second segment of the final sub-assembly to the second segment of the first sub-assembly.
Optionally, the upper faces of the electrical cells are coplanar, the lower faces of the electrical cells are coplanar, and the first and second busbar arrangements are within the confines of the planes defined by the upper and lower faces of the electrical cells.
Within the scope of this application, it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.
BRIEF DESCRIPTION OF THE DRAWINGS
One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figures 1A and 1B show an example electrical cell 100 for use in a traction battery; Figure 2 shows a first view of a traction battery assembly 200; Figure 3 shows a magnified view of a busbar arrangement 300; Figure 4A shows a cell busbar connected to one electrical cell; Figure 4B shows a cell busbar connected to two electrical cells; Figure 5 shows a flowchart of a method 500; Figure 6 shows a second traction battery assembly 600; Figure 7 illustrates the series connections within the second traction battery assembly; Figure 8 shows a battery pack 800; Figure 9 shows a flowchart of a method 900; and Figure 10 shows a vehicle in accordance with an embodiment of the invention.
DETAILED DESCRIPTION
The present invention relates to a traction battery assembly for use in a vehicle. A traction battery assembly comprises a plurality of electrical cells connected to provide power to an electric motor of an electric vehicle (EV), for example a battery electric vehicle (BEV) or hybrid electric vehicle (HEV).
Figures 1A and 1B illustrate an example electrical cell 100 for use in a traction battery assembly for a vehicle. Figure 1A shows the electrical cell 100 from a first angled view and Figure 1B shows the electrical cell 100 from a second side-on view. The cell 100 comprises a positive electrical terminal 100P and a negative electrical terminal 100N. In this example, the electrical cell 100 is a prismatic cell 100 having a first end face 110 and a second end face 120. The positive terminal 100P is provided on the first end face 110 and the negative terminal 100N is provided on the second end face 120. The prismatic cell 100 comprises an upper face 130, a lower face 140 and two side faces 150 each extending between the first end face 110 and the second end face 120. The upper face 130 is oriented in an upper plane 100U and the lower face 140 is oriented in a lower plane 100L. Other electrical cell types may alternatively be used in a traction battery pack, such as pouch cells or cylindrical cells.
Cells 100 such as shown in Figure 1 may be grouped together to create a traction battery assembly. Terminals 100P, 100N of cells 100 within a traction battery assembly are electrically connected together via busbars, wherein each busbar is an electrically conductive connecting element. It is desirable to reduce the total length of busbars within the battery assembly, in order to reduce energy loss from resistance and also to reduce the material cost of the busbars. Furthermore, it is desirable to reduce a volume required by the busbars in order to improve the energy density of the traction battery assembly. According to the present invention there is provided a busbar arrangement for use in connecting cells 100 within a traction battery assembly to reduce a volume of the traction battery assembly and thus improve an energy density of the traction battery assembly.
Furthermore, according to the present invention there is provided an arrangement of electrical cells within a traction battery assembly to reduce a total length of busbars required.
With reference to Figure 2, there is illustrated a portion of a traction battery assembly 200 according to an embodiment of the present invention.
The traction battery assembly 200 comprises at least a first electrical cell 210 and a second electrical cell 220, however it will be appreciated that the traction battery assembly 200 may comprise one or more additional electrical cells. Each of the first electrical cell 210 and the second electrical cell 220 may be of the type of cell 100 shown in Figures 1A and 1B. Thus, the first electrical cell 210 comprises a first cell terminal 211 disposed on a first end face 110 and a second cell terminal 212 disposed on a second end face 120. Likewise, the second electrical cell 220 comprises a first cell terminal 221 disposed on a first end face 110 and a second cell terminal 222 disposed on a second end face 120. The first cell terminal 211, 221 of each cell may be a positive cell terminal and the second cell terminal 212, 222 of each cell may be a negative cell terminal, or vice versa.
The first electrical cell 210 and second electrical cell 220 are electrically connected by a busbar arrangement 300. The busbar arrangement 300 is arranged to connect the first electrical cell 210 to the second electrical cell 220 in series, by electrically connecting the first cell terminal 211 of the first electrical cell 210 to the second cell terminal 222 of the second electrical cell 220. In some embodiments of the invention, the first electrical cell 210 forms part of a first battery sub-assembly and the second electrical cell 220 forms part of a second battery sub-assembly, as will be explained. Thus, the busbar arrangement 300 consequently acts to connect the first battery sub-assembly and second battery sub-assembly in series.
With reference to Figure 3, there is shown a magnified illustration of the busbar arrangement 300 according to some embodiments.
The busbar arrangement 300 comprises a first cell busbar 310. The first cell busbar 310 is connected to the first cell terminal 211 of the first electrical cell 210, thus providing an electrical connection to the first cell terminal 211. The first cell busbar extends from the first end face 110 of the first electrical cell 210 and is entirely located between a plane 210U of the upper face of the first electrical cell 210 and a plane 210L of the lower face of the first electrical cell 210. Consequently, the first cell busbar 310 does not take up any additional vertical space in the traction battery assembly as it is located entirely between the upper and lower planes of the first electrical cell. In some embodiments, the first cell busbar 310 may be located entirely between a plane of each side face 150 of the first electrical cell 210. Thus, the first cell busbar 310 may not take up any additional space beyond each side face of the first electrical cell 210.
The first cell busbar 310 is an L-shaped busbar comprising a terminal planar portion 311 and a protruding planar portion 312. The terminal planar portion 311 is arranged flush with the first cell terminal 211 and is substantially parallel to the first end face 110 of the first electrical cell 210. The terminal planar portion 311 is welded to the first cell terminal 211 of the first electrical cell 210 along a first welding region 211W, for example by laser welding or the like. The protruding planar portion 312 is connected to and substantially perpendicular to the terminal planar portion 311, and thus extends normal to the surface of the first end face 110 of the first electrical cell 210. As will be explained, the protruding planar portion 312 may be welded to a further cell busbar to provide an electrical connection to the first electrical cell 210.
The busbar arrangement 300 comprises a second cell busbar 320. The second cell busbar 320 is connected to the second cell terminal 222 of the second electrical cell 220, thus providing an electrical connection to the second cell terminal 222. The second cell busbar 320 extends from the second end face 120 of the second electrical cell 220 and is entirely located between a plane 220U of the upper face of the second electrical cell 220 and a plane 220L of the lower face of the second electrical cell 220. Consequently, as with the first cell busbar 310, the second cell busbar 320 does not take up any additional vertical space in the traction battery assembly as it is located entirely between the upper and lower planes of the second electrical cell. In some embodiments, as with the first cell busbar 310, the second cell busbar 320 may be located entirely between a plane of each side face 150 of the second electrical cell 220. Thus, the second cell busbar 320 may not take up any horizontal additional space beyond each side face of the second electrical cell 220.
As with the first cell busbar 310, the second cell busbar 320 illustrated is an L-shaped busbar comprising a terminal planar portion 321 and a protruding planar portion 322. The terminal planar portion 321 is arranged flush with the second cell terminal 222 and is substantially parallel to the second end face 120 of the second electrical cell 220. The terminal planar portion 321 is welded to the second cell terminal 222 of the second electrical cell 220 along a second welding region 222W, for example by laser welding or the like. The protruding planar portion 322 is connected to and substantially perpendicular to the terminal planar portion 321, and thus extends normal to the surface of the second end face 120 of the second electrical cell 220. As will be explained, the protruding planar portion 322 may be welded to the first cell busbar 310 to provide an electrical connection between the first electrical cell 210 and the second electrical cell 220.
The first electrical cell 210 and the second electrical cell 220 are arranged in the traction battery assembly 200 in an end face to end face manner, such that the first end face 110 of the first electrical cell 210 is arranged adjacent to and facing the second end face 120 of the second electrical cell 220. The first electrical cell 210 and the second electrical cell 220 are aligned such that their respective upper faces 130, lower faces 140 and side faces 150 are coplanar. Thus, the upper plane 210U of the first electrical cell is aligned with the upper plane 220U of the second electrical cell. Likewise, the lower plane 210L of the first electrical cell is aligned with the lower plane 220L of the second electrical cell 220. Although not shown, the plane of each side face 150 of the first electrical cell 210 may also be aligned with the plane of a corresponding side face 150 of the second electrical cell.
The first cell busbar 310 is welded directly to the second cell busbar 320 to provide an electrical connection between the first cell terminal 211 of the first electrical cell 210 and the second cell terminal 222 of the second electrical cell 220. In a typical prior art vehicle battery assembly, when electrically connecting different subassemblies or modules within the assembly, a third connecting busbar will be implemented between the first cell busbar 310 and the second cell busbar 320. This third connecting busbar extends above the upper plane of the cells or beyond a side of the cells, thus invading the side vehicle crash plane or the space above the cells in the vehicle. Advantageously, welding the first cell busbar 310 directly to the second cell busbar 320 according to the present disclosure negates need for a third connecting busbar. By implementing a busbar connection 300 according to the present invention between vehicle sub-assemblies or modules, the need for a third connecting busbar is removed.
The protruding planar portion 312 of the first cell busbar 310 is overlapped with the protruding planar portion 322 of the second cell busbar 320. The protruding planar portions 312, 322 are arranged flush along an overlap portion 330, with the protruding planar portion 322 of the second cell busbar arranged above the protruding planar portion 312 of the first cell busbar 310. The protruding planar portions 312, 322 are welded together along the overlap portion 330, by laser welding or the like to provide a conductive join between the busbars 310, 320 at the overlap portion 330. The total width of the overlap portion 330 along a direction normal to the end faces 110, 120 should be at least five times the thickness of the thinnest protruding planar portion 312, 322. For example, if the second protruding planar portion 322 has a minimum thickness of 4mm, the overlap portion 330 should provide an overlap of at least 20mm. This facilitates a sufficient current flow through the busbar arrangement 300. Furthermore, in some embodiments there is a ratio of at least 1.5 between a thickness of the protruding planar portion 312 of the first cell busbar 310 to the thickness of the protruding planar portion 322 of the second cell busbar 320. That is, the protruding planar portion 312 of the first cell busbar 310 (i.e., the lower portion in the overlap 330) is at least 50% thicker than the protruding portion 322 of the second cell busbar 320 (i.e., the upper portion in the overlap 330). This is to improve the laser welding process. Furthermore, it helps to maintain a suitable temperature when current is applied through the join at the overlap portion 330.
As described, the first and second cell busbar 310, 320 are bounded entirely between the upper plane and the lower plane of each cell 210, 220, and the cells are aligned. Thus, the electrical connection provided by the busbar arrangement 300 can be entirely situated between the cells 210, 220 without invading any space in a side vehicle crash plane or adding any height to the pack in a direction normal to the upper plane of the cells. Thus, by providing the busbar arrangement 300 between adjacent sub-assemblies or modules within the vehicle battery assembly, the space taken up by busbars across the vehicle battery assembly can be reduced and thus the energy density of the vehicle battery can be improved.
In some embodiments, one of the first cell busbar 310 and the second cell busbar 320 is a flexible laminated busbar. The other of the first cell busbar 310 and the second cell busbar 320 is rigid or inflexible. In the illustrated embodiment, the first cell busbar 310 is a solid inflexible busbar and the second cell busbar 320 is a flexible laminated busbar. The flexibility of the flexible laminated busbar may be provided by constructing the busbar with laminated layers of material. By providing one flexible busbar, advantageously the busbar arrangement 300 is robust to vehicle vibrations, even when both busbars 310, 320 are very short. Thus, a total length of the busbar arrangement 300 can be reduced without causing increased risk of damage from vehicle vibrations. By using only one flexible busbar rather than two, the solid busbar can support the flexible busbar during assembly, avoiding a potential short circuit. Furthermore, a solid busbar may be more easily manufactured to have a variable cross section which can be beneficial when welding the first cell busbar 310 and second cell busbar 320 together. Each of the first cell busbar 310 and the second cell busbar 320 are formed from the same material. In some embodiments, each busbar 310, 320 is formed from aluminium, which provides a beneficial weight reduction to the vehicle battery. However, it can be envisaged in other embodiments each busbar 310, 320 can be formed from another suitably conductive material such as copper.
With reference to Figures 4A and 4B, the first cell busbar 310 may in some embodiments provide an electrical connection to two first electrical cells 410, 420. That is, the terminal planar portion of the first cell busbar 310 may be disposed across the first end faces of two first electrical cells 410, 420. The two first electrical cells 410, 420 are arranged side face to side face such that the first end face 110 of each cell 410, 420 is substantially co-planar. The two first electrical cells 410, 420 may be arranged as part of the same module or sub-assembly, as will be explained. The first cell busbar 310 is welded to the first cell terminal of each of the first electrical cells 410, 420. Thus, the first cell busbar 310 provides a parallel electrical connection between the two first electrical cells 410, 420. The two first electrical cells 410, 420 may thus be considered to be a single unit or cell group within the sub-assembly, wherein a single unit or cell group comprises a plurality of electrical cells connected in parallel. Although the illustrated embodiment shows two first electrical cells 410, 420 forming a cell group, it can be envisaged that in other embodiments, more than two first electrical cells may form a cell group. Likewise, the second cell busbar 320 may provide an electrical connection to a plurality of second electrical cells connected in parallel to form a cell group. Thus, the busbar arrangement 300 may provide an electrical connection in series between a first cell group of a first sub-assembly and a second cell group of a second sub-assembly.
With reference to Figure 5, there is illustrated a flow chart of a method 500 of connecting electrical cells within a traction battery assembly. The method 500 is for connecting a first electrical cell 210 and a second electrical cell 220 of the traction battery assembly in series by constructing a busbar arrangement 300 such as shown in Figures 2 and 3.
The method 500 comprises a block 510 of providing the first electrical cell 210 and the second electrical cell 220. Each of the first electrical cell 210 and the second electrical cell 220 are of the type illustrated in Figures 1A and 1B. That is, each of the electrical cells comprises a first cell terminal situated on a first end face 110, a second cell terminal situated on a second end face 120, an upper face 130, a lower face 140, and two opposing side faces 150, each of the upper face 130, lower face 140 and opposing side faces 150 extending between the first end face 110 and the second end face 120.
The method 500 comprises a block 520 of connecting a first cell busbar 310 to a first cell terminal 211 of the first electrical cell 210, such as by welding the first cell busbar 310 to the first cell terminal 211 over a welding area 211W. The connection is such that the first cell busbar 310 extends from the first end face 110 of the first electrical cell 210 and is entirely located between a plane of the upper face 130 of the first electrical cell 120 and a plane of the lower face 140 of the first electrical cell 210.
The method 500 comprises a block 530 of connecting a second cell busbar 320 to the second cell terminal 222 of the second electrical cell 220, such as by welding the second cell busbar 320 to the second cell terminal 222 over a welding area 222W. The connection is such that the second cell busbar 320 extends from the second end face 120 of the second electrical cell 220 and is entirely located between a plane of the upper face of the second electrical cell 220 and a plane of the lower face 140 of the second electrical cell 220.
The method 500 comprises a block 540 of welding the first cell busbar 310 directly to the second cell busbar 320 to provide an electrical connection between the first cell terminal 211 of the first electrical cell 210 and the second cell terminal 222 of the second electrical cell 220.
With reference to Figure 6, there is shown a traction battery assembly 600 according to some embodiments of the invention. The traction battery assembly 600 provides an arrangement of electrical cells to reduce a total length of busbars required within the assembly. The traction battery assembly 600 may be implemented in isolation, or may be combined with one or more of the busbar arrangement 300, as will be explained.
The traction battery assembly 600 comprises a plurality of battery sub-assemblies 610, 620, 630, 640. Although the traction battery assembly 600 illustrated comprises four sub-assemblies, in other embodiments it can be envisaged that any number of sub-assemblies may be provided. The structure of each sub-assembly 610, 620, 630, 640 will be described with reference to a first of the sub-assemblies 610, however the description applies equally to the further sub-assemblies 620, 630, 640.
The first sub-assembly 610 comprises a plurality of electrical cells. Each electrical cell may take the form of the electrical cell 100 illustrated in Figures 1A and 1B. Thus, each electrical cell 100 comprises a first cell terminal 100P situated on a first end face 100, a second cell terminal 100N situated on a second end face 120, an upper face 130, a lower face 140, and two opposing side faces 150, each of the upper face 130, lower face 140 and opposing side faces 150 extending between the first end face 110 and the second end face 120. The plurality of electrical cells 100 of the first sub-assembly 610 are stacked side face 150 to side face 150 extending along a first dimension x between a first end cell 611 and a second end cell 613. Thus, the upper surface 130 of each of the plurality of electrical cells 100 within the first sub-assembly is coplanar to form an upper surface of the sub-assembly, and the lower surface 140 of each of the plurality of electrical cells 100 is coplanar to form a lower surface of the sub-assembly. A respective side face 150 of each of the first end cell 611 and second end cell 613 forms a respective end surface of the sub-assembly.
The first sub-assembly 610 is divided along the first dimension x into at least a first segment 600-a including the first end cell 611 and a second segment 600-b including the second end cell 613. In other embodiments, the first sub-assembly 610 may be divided into more than two segments. Preferably the number of segments is a multiple of two in order to facilitate out and back connections as will be explained. For example, the first sub-assembly may be divided into four segments or eight segments. The divide between the first segment 600-a and the second segment 600-b is illustrated by a dividing center line C in Figure 6. The cells within the first segment 600-a are electrically connected to each other, and the cells within the second segment 600-b are electrically connected to each other, as explained below.
The electrical cells within each segment 600-a, 600-b may be grouped in cell groups, or sub-segments 612.
The sub-segments 612 comprise one or more neighbouring cells 100 electrically connected in parallel via internal busbars 614. In the illustrated embodiment, each sub-segment 612 comprises two cells 100, however in other embodiments each sub-segment 612 may comprise only one cell, or more than two cells. Within a sub-segment 612, the electrical cells are aligned such that the first end face 110 of each cell 100 within the sub-segment 612 is co-planar, and the second end face 110 of each cell 100 within the sub-segment 612 is co-planar. Thus, by welding an internal busbar 614 across the positive terminals 100P of each cell 100 and another internal busbar 614 across the negative terminals 100N of each cell 100, the cells may be readily connected in parallel within the sub-segment 612. Adjacent sub-segments 612 are then electrically connected in series across the segment. This is achieved by orienting adjacent sub-segments 612 such that they are rotated 180 degrees with respect to each other. Thus, the first end face 110 of a first sub-segment 612 will be co-planar with the second end face 120 of its neighbouring sub-segment 612. The internal busbars 614 may thus be welded to the positive terminals of cells within the first sub-segment 612 and the negative terminals of cells within the neighbouring sub-segment 612, to connect the neighbouring sub-segments in series.
Within the sub-assembly 610, no internal busbars 614 are provided between the first segment 600-a and the second segment 600-b. Thus, within the sub-assembly 610, the two segments 600-a, 600-b are not directly electrically connected.
As discussed, each of the sub-assemblies 620, 630 may be constructed analogously to the first sub-assembly 610. However, the final sub-assembly 640 differs from the other sub-assemblies in the fact that the first segment 600-a and the second segment 600-b of the final sub-assembly 640 are connected in series via the internal busbars 614.
The plurality of sub-assemblies 610, 620, 630, 640 are stacked within the traction battery assembly 600 in a second dimension y perpendicular to the first dimension x, extending from the first sub-assembly 610 to a final sub-assembly 640. The sub-assemblies 610, 620, 630,640 are aligned, such that respective end cells of each sub-assembly 610, 620, 630, 640 are coplanar.
A respective first busbar arrangement 650-a is disposed between the first segment 600-a of each pair of neighbouring sub-assemblies to electrically connect the first segment 600-a of each pair of neighbouring sub-assemblies in series. The first busbar arrangement 650-a may be provided at alternating ends of the first segment 600-a as shown. In this way, the sub-segments 612 will be connected in series along each first segment 600-a of each sub-assembly in turn, from the first sub-assembly 610 to the final sub-assembly 640.
A respective second busbar arrangement 650-b is disposed between the second segment 600-b of each pair of neighbouring sub-assemblies to electrically connect the second segment of each pair of neighbouring sub-assemblies in series. The second busbar arrangement 650-b may be provided at alternating ends of the second segment 600-b as shown. In this way, the sub-segments 612 will be connected in series along each second segment 600-b of each sub-assembly in turn, from the final sub-assembly 640 to the first sub-assembly 610.
As discussed, the first segment 600-a and the second segment 600-b of the final sub-assembly 640 are connected together in series. Thus, with reference to Figure 7, it can be seen that the sub-segments 612 of the traction battery assembly 600 are connected in series along each first segment 600-a from the first segment of the first sub-assembly 610 to the first segment of the final sub-assembly 640, and back along each second segment 600-b from the second segment of the final sub-assembly 640 to the second segment of the first sub-assembly 610.
The traction battery assembly 600 is thus arranged in a compact form which only requires short busbars between neighbouring sub-assemblies and no long busbars.
The traction battery assembly 600 comprises a first battery terminal 660-a on the first segment 600-a of the first sub-assembly 610 and a second battery terminal 660-b on the second segment 600-b of the first subassembly 610. The first and second battery terminals 610 are for connecting the traction battery assembly to a traction motor of the vehicle. Advantageously, the first battery terminal 660-a and second battery terminal 660-b are arranged on a same side of the traction battery assembly 600 because the cells are connected in an "out and back" manner across the sub-assemblies. It will be appreciated that this will also be the case even if the traction battery assembly 600 was adapted to be divided into four segments, eight segments or the like. Thus, the fact that the connecting terminals of the assembly 600 can be co-located on the first sub-assembly 610 facilitates short end busbar connections from the assembly 600 to the traction motor.
Some or each respective first and second busbar arrangement 650-a, 650-b may be arranged as in the busbar arrangement 300 described with reference to Figures 2 and 3. Each busbar arrangement 650-a, 650-b electrically connects a first electrical cell of a respective first sub-assembly to a second electrical cell of a respective neighbouring second sub-assembly. As shown in Figures 2 and 3, each busbar arrangement can thus comprise a first cell busbar 310 connected to the first cell terminal of the first electrical cell and a second cell busbar 320 connected to the second cell terminal of the second electrical cell, wherein the first cell busbar 310 is welded directly to the second cell busbar 320.
Thus, adjacent sub-assemblies can be electrically connected by directly welding cell busbars of adjacent cells together, negating the need for a third connecting busbar. Furthermore, as described, the first and second cell busbar 310, 320 are bounded between the upper plane and the lower plane of each cell, thus the electrical connection within the assembly 600 can be entirely routed between the sub-assemblies without extending into a side vehicle crash plane or extending above the cells within the vehicle.
For at least some of the busbar arrangements, such as the busbar arrangements connecting the sub-assemblies 610 and 620 in Figure 6 and 7, the first and second electrical cells are disposed in the middle of each respective sub-assembly. That is, the first electrical cell is disposed between the first end cell 611 and the second end cell 613 of the respective first sub-assembly 610, and the second electrical cell is disposed between a first end cell and a second end cell of the respective second neighbouring sub-assembly 620.
Therefore, electrical connections are provided between the sub-assemblies 610, 620 centrally in each sub-assembly. This occurs due to the arrangement of the segments 600-a, 600-b. For the illustrated arrangement, such a central connection occurs for every other neighbouring pair of sub-assemblies.
With reference to Figure 8, there is shown a battery pack 800 according to an embodiment of the invention.
The battery pack 800 comprises a first traction battery assembly 840 and a second battery assembly 850.
Each of the first and second battery assemblies 840, 850 may take the form of the battery assembly 600 described with reference to Figures 6 and 7.
The battery pack 800 further comprises a switching mechanism 810 arranged to electrically connect the first traction battery assembly 840 with the second traction battery assembly 850 in series or parallel. The switching mechanism 810 may thus be connected to the battery terminals 660-a, 660-b of each assembly 840, 850. The battery pack 800 may further comprise a battery control module 820 which is schematically illustrated in Figure 8. The battery control module 820 is operatively connected to the switching mechanism 810 and arranged to control the switching mechanism 810 to switch between the series and parallel connections. By providing a switching function operable to connect the two assemblies 840, 850 in either series or parallel, advantageously the voltage across the battery pack 800 can be effectively doubled or halved. This can be useful in order to facilitate rapid, higher voltage charging of the battery pack 800.
Although the first battery assembly 840 and second battery assembly 850 are arranged side by side along the second dimension y in Figure 8, in some embodiments the second traction battery assembly 850 is stacked together with the first traction battery assembly 840 along a third dimension z perpendicular to the first dimension x and second dimension y. This arrangement can provide an improved space efficiency of the battery pack 800, particularly as by utilising the busbar arrangements 300, no busbars are required to extend above an upper plane of the cells or below a lower plane of the cells in the third dimension z. With reference to Figure 9, there is illustrated a flow chart of a method 900 of connecting electrical cells within a traction battery assembly according to an embodiment. The method 900 is for arranging electrical cells to provide the traction battery assembly 600 illustrated in Figures 6 and 7.
The method 900 comprises a block 910 of providing a plurality of electrical cells. Each electrical cell is of the type of the electrical cell 100 shown in Figures 1A and 1B. Each electrical cell 100 thus comprises a first cell terminal 100P situated on a first end face 110, a second cell terminal 100N situated on a second end face 120, an upper face 130, a lower face 140, and two opposing side faces 150, each of the upper face 130, lower face 140 and opposing side faces 150 extending between the first end face 110 and the second end face 120.
The method 900 comprises a block 920 of constructing a plurality of sub-assemblies 610, 620, 630, 640. Constructing each sub-assembly comprises stacking a plurality of the electrical cells 100 side face to side face extending along a first dimension x. In block 930, each sub-assembly 610, 620, 630, 640 is divided along the first dimension x into at least a first segment 600-a and a second segment 600-b. The block 930 comprises electrically connecting the cells of within each first segment 600-a, and electrically connecting the cells within each second segment 600-b. In block 940, the method comprises stacking the plurality of sub-assemblies 610, 620, 630, 640 in a second dimension y perpendicular to the first dimension x, extending from a first subassembly 610 to a final sub-assembly 640.
In block 950, the first segment 600-a of each pair of neighbouring sub-assemblies are electrically connected in series by providing a respective first busbar arrangement 650-a disposed between the first segment 600-a of each pair of neighbouring sub-assemblies. In block 960, the method 900 comprises electrically connecting the second segment of each pair of neighbouring sub-assemblies in series by providing a respective second busbar arrangement 650-b disposed between the second segment 600-b of each pair of neighbouring subassemblies.
In block 970, the method comprises electrically connecting the first segment 600-a and the second segment 600-b of the final sub-assembly 640 in series. As a result, as discussed with reference to Figures 6 and 7, the segments of the traction battery assembly 600 are connected in series along each first segment 600-a from the first segment of the first sub-assembly 610 to the first segment of the final sub-assembly 640, and back along each second segment 600-b from the second segment of the final sub-assembly 640 to the second segment of the first sub-assembly 610.
With reference to Figure 10, there is illustrated a vehicle 1000. According to embodiments of the invention, the vehicle 1000 may be provided with the traction battery assembly 200 or 600 or the battery pack 800. The vehicle is an electric vehicle (EV), for example a battery electric vehicle (BEV) or hybrid electric vehicle (HEV).
It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims (15)

  1. CLAIMS1. A traction battery assembly for a vehicle, the traction battery assembly comprising: a plurality of battery sub-assemblies, each sub-assembly comprising a respective plurality of electrical cells, each electrical cell comprising a first cell terminal situated on a first end face, a second cell terminal situated on a second end face, an upper face, a lower face, and two opposing side faces, each of the upper face, lower face and opposing side faces extending between the first end face and the second end face, wherein the plurality of electrical cells of each sub-assembly are stacked side face to side face extending along a first dimension, and wherein: the plurality of sub-assemblies are stacked in a second dimension perpendicular to the first dimension, extending from a first sub-assembly to a final sub-assembly, and each sub-assembly is divided along the first dimension into at least a first segment and a second segment, wherein the cells within the first segment are electrically connected and wherein the cells within the second segment are electrically connected; a respective first busbar arrangement disposed between the first segments of each pair of neighbouring sub-assemblies to electrically connect the first segments of each pair of neighbouring sub-assemblies in series; a respective second busbar arrangement disposed between the second segments of each pair of neighbouring sub-assemblies to electrically connect the second segments of each pair of neighbouring sub-assemblies in series; wherein the first segment and the second segment of the final sub-assembly are connected together in series, such that the segments of the traction battery assembly are connected in series along each first segment from the first segment of the first sub-assembly to the first segment of the final subassembly, and back along each second segment from the second segment of the final sub-assembly to the second segment of the first sub-assembly.
  2. 2. The traction battery assembly of claim 1, wherein the traction battery assembly comprises a first battery terminal on the first segment of the first sub-assembly and a second battery terminal on the second segment of the first sub-assembly, wherein the first and second battery terminals are for connecting the traction battery assembly to a traction motor of the vehicle.
  3. 3. The traction battery assembly of claim 1 or 2, wherein each respective first and second busbar arrangement electrically connects a first electrical cell of a respective first sub-assembly to a second electrical cell of a respective neighbouring second sub-assembly, each first and second busbar arrangement comprising: a first cell busbar connected to the first cell terminal of the first electrical cell; and a second cell busbar connected to the second cell terminal of the second electrical cell, wherein the first cell busbar is welded directly to the second cell busbar to provide an electrical connection between the first cell terminal of the first electrical cell and the second cell terminal of the second electrical cell.
  4. 4. The traction battery assembly of claim 3, wherein for each first and second busbar arrangement: the first cell busbar extends from the first end face of the first electrical cell and is entirely located between a plane of the upper face of the first electrical cell and a plane of the lower face of the first electrical cell; the second cell busbar extends from the second end face of the second electrical cell and is entirely located between a plane of the upper face of the second electrical cell and a plane of the lower face of the second electrical cell and wherein the upper face of the first electrical cell and the upper face of the second electrical cell are coplanar, and the lower face of the first electrical cell and the lower face of the second electrical cell are coplanar.
  5. 5. The traction battery assembly of claim 3 or 4, wherein in each respective first and second busbar arrangement, one of the first cell busbar and the second cell busbar is a flexible laminated busbar.
  6. 6. The traction battery assembly of any of claims 3 to 5, wherein in each respective first and second busbar arrangement: each of the first cell busbar and second cell busbar is an L-shaped busbar comprising a terminal planar portion welded to the respective cell terminal and a protruding planar portion substantially perpendicular to the terminal planar portion; and the protruding planar portion of the first cell busbar is welded along an overlap to the protruding planar portion of the second cell busbar.
  7. 7. The traction battery assembly of any of claims 3 to 6, wherein for at least one of the respective first or second busbar arrangements within the assembly the first electrical cell is disposed between a first end cell and a second end cell of the respective first sub-assembly, and the second electrical cell is disposed between a first end cell and a second end cell of the respective second neighbouring sub-assembly.
  8. 8. The traction battery assembly of any preceding claim, wherein each segment comprises one or more sub-segments, each sub-segment comprising two or more electrical cells connected in parallel, wherein the one or more sub-segments are connected in series within the segment.
  9. 9. A battery pack comprising: a first traction battery assembly according to any preceding claim, a second traction battery assembly according to any preceding claim, and a switching mechanism arranged to selectively electrically connect the first traction battery assembly with the second traction battery assembly in series or parallel.
  10. 10. The battery pack of claim 9, wherein the second traction battery assembly is stacked together with the first traction battery assembly along a third dimension perpendicular to the first dimension and second dimension.
  11. 11. The battery pack of claim 9 or 10, further comprising a battery control module operatively connected to the switching mechanism, wherein the battery control module is arranged to control the switching mechanism to switch between the series and parallel connections.
  12. 12. A vehicle comprising a traction battery assembly according to any of claims 1 to 8 or a battery pack according to any of claims 9 to 11.
  13. 13. A method of connecting electrical cells within a traction battery assembly, the method comprising: providing a plurality of electrical cells, each electrical cell comprising a first cell terminal situated on a first end face, a second cell terminal situated on a second end face, an upper face, a lower face, and two opposing side faces, each of the upper face, lower face and opposing side faces extending between the first end face and the second end face, constructing a plurality of sub-assemblies, wherein constructing each sub-assembly comprises stacking a plurality of the electrical cells side face to side face extending along a first dimension, dividing each sub-assembly along the first dimension into at least a first segment and a second segment, electrically connecting the cells of the first segment, and electrically connecting the cells of the second segment; stacking the plurality of sub-assemblies in a second dimension perpendicular to the first dimension, extending from a first sub-assembly to a final sub-assembly; electrically connecting the first segment of each pair of neighbouring sub-assemblies in series by providing a respective first busbar arrangement disposed between the first segment of each pair of neighbouring sub-assemblies; electrically connecting the second segment of each pair of neighbouring sub-assemblies in series by providing a respective second busbar arrangement disposed between the second segment of each pair of neighbouring sub-assemblies; and electrically connecting the first segment and the second segment of the final sub-assembly in series, such that the segments of the traction battery assembly are connected in series along each first segment from the first segment of the first sub-assembly to the first segment of the final sub-assembly, and back along each second segment from the second segment of the final sub-assembly to the second segment of the first sub-assembly.
  14. 14. A method as claimed in claim 13 wherein the upper faces of the electrical cells are coplanar, the lower faces of the electrical cells are coplanar, and the first and second busbar arrangements are within the confines of the planes defined by the upper and lower faces of the electrical cells.
  15. 15. A traction battery assembly for a vehicle comprising at least: a first electrical cell and a second electrical cell, each of the first and second electrical cell comprising a first cell terminal situated on a first end face, a second cell terminal situated on a second end face, an upper face, a lower face, and two opposing side faces, each of the upper face, lower face and opposing side faces extending between the first end face and the second end face; and a busbar arrangement for electrically connecting the first electrical cell to the second electrical cell, the busbar arrangement comprising: a first cell busbar connected to the first cell terminal of the first electrical cell, wherein the first cell busbar extends from the first end face of the first electrical cell and is entirely located between a plane of the upper face of the first electrical cell and a plane of the lower face of the first electrical cell; and a second cell busbar connected to the second cell terminal of the second electrical cell, wherein the second cell busbar extends from the second end face of the second electrical cell and is entirely located between a plane of the upper face of the second electrical cell and a plane of the lower face of the second electrical cell, wherein the first cell busbar is welded directly to the second cell busbar to provide an electrical connection between the first cell terminal of the first electrical cell and the second cell terminal of the second electrical cell.
GB2218942.7A 2022-12-15 2022-12-15 Battery assembly for vehicle Pending GB2625519A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB2218942.7A GB2625519A (en) 2022-12-15 2022-12-15 Battery assembly for vehicle
PCT/EP2023/085873 WO2024126711A1 (en) 2022-12-15 2023-12-14 Battery assembly for vehicle

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2218942.7A GB2625519A (en) 2022-12-15 2022-12-15 Battery assembly for vehicle

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GB2625519A true GB2625519A (en) 2024-06-26

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Citations (2)

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EP3667760B1 (en) * 2018-12-11 2020-12-09 Samsung SDI Co., Ltd. Battery module
US20210359368A1 (en) * 2018-09-18 2021-11-18 Mclaren Automotive Limited Battery assembly

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Publication number Priority date Publication date Assignee Title
JP5428386B2 (en) * 2009-02-25 2014-02-26 株式会社デンソー Battery system
JP6988393B2 (en) * 2017-11-13 2022-01-05 トヨタ自動車株式会社 Battery module and battery pack
US20230202345A1 (en) * 2020-01-23 2023-06-29 Sanyo Electric Co., Ltd. Power supply device, and electric vehicle and power storage device equipped with this power supply device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210359368A1 (en) * 2018-09-18 2021-11-18 Mclaren Automotive Limited Battery assembly
EP3667760B1 (en) * 2018-12-11 2020-12-09 Samsung SDI Co., Ltd. Battery module

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WO2024126711A1 (en) 2024-06-20

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