CN115066797A

CN115066797A - Battery module and battery pack

Info

Publication number: CN115066797A
Application number: CN202080096174.6A
Authority: CN
Inventors: O.斯特鲁特; C.盖斯凯尔
Original assignee: Dyson Technology Ltd
Current assignee: Dyson Technology Ltd
Priority date: 2019-12-19
Filing date: 2020-10-14
Publication date: 2022-09-16
Also published as: GB2590615A; GB2590615B; GB201918797D0; WO2021123711A1

Abstract

A battery module (110) is disclosed having a support (120), a plurality of battery cells (130) arranged in rows on the support (120), and at least one bus bar (160) electrically connecting the battery cells (130) to form a plurality of rows of groups of parallel-connected battery cells. Each bank has battery cells (130) in at least two rows. At least one bus bar (160) having a ridge (162), a positive connection portion (163a) extending from a first side of the ridge (162) and connected to positive terminals (133) of at least two battery cells (130) in different rows of battery cells connected in parallel in a first row group; and a negative connection portion (163b) extending from a second opposite side of the spine (162) and connected to negative terminals (134) of at least two cells (130) in different rows of cells connected in parallel in the second row group.

Description

Battery module and battery pack

Technical Field

The present invention relates to batteries and, more particularly, but not exclusively, to a battery module and a battery pack including the same. The battery module and the battery pack are particularly suitable for electric vehicles.

Background

Batteries are an integral part of many electrical and electronic systems, including electric vehicles and energy storage devices. A battery pack may generally include a plurality of individual battery cells electrically connected to form one or more battery modules. It can be challenging to electrically connect the battery cells in a manner that provides the desired electrical output of the battery module in an efficient manner while reducing losses, weight, and cost and increasing ease of manufacture.

Accordingly, there is a need to provide a practical and reliable battery pack that is easy to manufacture and operates efficiently. Reducing the weight of the battery pack is a desire in the electric vehicle field to improve the performance and efficiency of the electric vehicle.

Disclosure of Invention

According to a first aspect of the present invention, there is provided a battery module including a support, a plurality of battery cells arranged in rows on the support, and at least one bus bar electrically connecting the battery cells to form a plurality of row groups of battery cells connected in parallel, each of the row groups including battery cells in at least two rows. The at least one bus bar includes a spine, a positive connection portion extending from a first side of the spine and connected to positive terminals of at least two battery cells in different rows of a first row group of battery cells connected in parallel, and a negative connection portion extending from a second opposite side of the spine and connected to negative terminals of at least two battery cells in different rows of a second row group of battery cells connected in parallel.

In this manner, the at least one bus bar may be configured to electrically connect the positive terminals of the battery cells in the first row of assembled battery cells in parallel, and the negative terminals of the battery cells in the second row of assembled battery cells in parallel, and to electrically connect the first row group and the second row group in series. The second row group of battery cells may be adjacent to the first row group.

The at least one bus bar may include an equal number of positive and negative connection portions. The at least one bus bar may include a total of equal number of connections on opposing sides of the spine at any particular point along the spine. In this way, current can flow from the positive connection portion through the ridge to the negative connection portion.

The battery module may be used for an electric vehicle.

The battery module may include at least one bus bar including a substantially straight elongated ridge, and at least one other bus bar including a curved ridge.

The straight ridge may be adjacent to a single row of cells. The curved ridge may include at least a first portion adjacent to a cell in the first row of cells and a second portion offset from the first portion and adjacent to a cell in the second row of cells. The curved ridges may allow the battery cells in non-adjacent rows to be connected in parallel without requiring connecting portions that extend from the ridges to a large extent.

The ridge of the at least one bus bar may be configured to bridge the underlying battery cell terminal.

In other words, the at least one bus bar may be configured such that the ridge of the at least one bus bar is located above and spaced apart from the battery cell terminal below such that the ridge does not contact the battery cell terminal below. In this way, current can flow from the positive connection portion through the ridge to the negative connection portion and between the battery cells connected thereto.

Each battery cell may include a first end and a second end, wherein the first end includes a positive terminal and a negative terminal of the battery cell, and the second end is mounted to the support.

The battery cells may be hexagonally close packed on the support. The battery module may include a plurality of cell stacks, each including a plurality of rows of battery cells electrically connected by a respective at least one bus bar. The support may be planar and may include opposing first and second faces. A first plurality of battery packs may be mounted on the first face and a second plurality of battery packs may be mounted on the second face. Adjacent groups of cells on the same face may be spaced apart to form respective channels therebetween. The support may be a cooling plate.

The first ends of the battery cells may be coplanar. The positive and negative electrode connection parts may be coplanar. The ridge may lie in a plane parallel to and spaced above the connection portion.

The first end of the battery cell and the positive and negative connection portions may lie in a first plane, and the ridge may lie in a second plane that is parallel to and spaced above the first plane. The positive and negative electrode connection parts may include a bridge part extending from the first plane to the second plane. The bridge portion extends up to or above the second plane.

One or more of the following: a first end of the battery cell; a positive electrode connecting portion; and/or the negative connection portion may be located slightly above or below the first plane, for example up to two, five or ten times the average thickness of the or each bus bar above or below the first plane.

For each battery cell, the positive terminal may include one of a central protrusion on a first end of the battery cell and an annular portion on the first end of the battery cell, the annular portion being concentric about the central protrusion. The negative terminal may include the other of the central protrusion and the annular portion.

The annular protrusion may be defined by a rim or edge of the housing or can of the battery cell.

The battery module may include a plurality of bus bars, and each of the battery cells may be connected to a positive connection portion of a first bus bar and a negative connection portion of a second bus bar adjacent to the first bus bar. The positive connection portion of the first bus bar and the negative connection portion of the second bus bar may be shaped to conform to the shape of each other and to be spaced apart from each other for respective positive and negative connections to each battery cell.

A gap may exist between the positive and negative connection portions to maintain electrical isolation, for example, to prevent shorting.

The battery module may include a single-layer bus bar. The connecting portion of each bus bar may be coplanar with the connecting portion of each other bus bar. The ridge portion of each bus bar may be coplanar with the ridge portion of each other bus bar.

Arranging the bus bars in a single layer may eliminate the need to provide insulation between the bus bars, thereby reducing the complexity of the battery module and reducing material costs.

One or more of the bus bars or portions thereof may be located slightly above or below another bus bar in the same plane, for example up to two, five or ten times the average thickness of the or each bus bar above or below the first plane. This slight deviation can still be broadly considered to constitute a monolayer.

The positive and negative connection portions may each include respective one or more positive and negative lateral projections arranged along respective first and second sides of the spine.

The positive lateral protrusion may be electrically connected to a positive terminal of the one or more battery cells, and the negative lateral protrusion may be electrically connected to a negative terminal of the one or more battery cells. The positive and negative lateral projections may provide flexible or resilient cantilevers extending from the spine. This may facilitate attachment of the lateral protrusions to the respective battery cell terminals, for example by welding portions of the lateral protrusions to the battery cell terminals.

The at least one bus bar may include positive and negative lateral protrusions of different shapes.

The at least one bus bar may include a repeating pattern of positive and negative lateral protrusions along the spine.

In this way, the bus bars may be formed/stamped from a single sheet from a repeating die plate. This may result in less material waste and lower manufacturing costs.

The battery module may include a plurality of bus bars, and the positive lateral protrusions of a first bus bar may be interleaved with the negative lateral protrusions of an adjacent second bus bar.

The negative lateral protrusions of the first bus bar may be staggered with the positive lateral protrusions of the adjacent third bus bar.

Each positive lateral projection may include at least one positive contact for electrically connecting to a positive terminal of a respective at least one battery cell, and each negative lateral projection may include at least one negative contact for electrically connecting to a negative terminal of a respective at least one other battery cell.

Each positive contact may be suitably shaped and arranged to electrically connect the positive lateral protrusions to a respective battery cell. Each negative contact may be suitably shaped and arranged to electrically connect the negative lateral protrusion to a respective battery cell.

The at least one positive contact may include a circular portion and the at least one negative contact may include a semi-annular portion when viewed in a direction orthogonal to a plane of the bus bar.

Therefore, the shapes of the positive contact and the negative contact can be matched with the shapes of the respective positive terminal and the negative terminal, so that reliable connection is ensured, and the manufacturing efficiency is improved.

The at least one positive lateral projection may include two or more positive contacts for connection to positive terminals of the respective two or more battery cells, and the at least one negative lateral projection may include two or more negative contacts for connection to negative terminals of the respective two or more other battery cells.

Two or more cells may be in the same row or in different rows.

At least one of the bus bars may have an equal number of positive and negative contacts.

The at least one busbar may comprise a total of equal number of connections on opposing sides of the spine at any point along the spine. In this way, current may flow through the ridge, and current along the ridge may be reduced. This may improve the accuracy of the sensed feature at the end of the ridge.

Positive and negative contacts may be welded to respective battery cell terminals to maintain electrical contact.

The positive contact may include an aperture through which at least a portion of the weld is visible.

The negative contact may include an aperture through which at least a portion of the weld is visible. In this way, the quality of the weld can be checked.

The positive and negative connection portions may include respective positive and negative bridge portions each extending over and spaced apart from the underlying cell terminal.

The at least one bus bar may be configured such that the positive and negative bridge portions do not contact the underlying battery cell terminals. The ridges may be spaced above and away from the underlying battery cell. One or more positive bridge portions may connect the respective one or more positive contacts to the spine. One or more negative bridge portions may connect the respective one or more negative contacts to the spine.

The battery module may include at least two bus bars having the same form and/or at least two bus bars substantially inlaid with each other.

In this way, multiple bus bars may be formed or stamped from the same piece of material, such as by using a stencil. This may result in less material waste and lower manufacturing costs.

The battery cells may be arranged in rows at least partially through a battery cell carrier that includes a plurality of apertures and each aperture includes a respective battery cell therethrough.

At least one bus bar may include a mounting or securing feature disposed along the ridge for securing the at least one bus bar to the battery cell carrier.

The battery cell carrier may include one or more securing features corresponding to the one or more securing features of the at least one bus bar, and the at least one bus bar may be mounted to the battery cell carrier and aligned with respect to the plurality of battery cells by the corresponding securing features.

The battery cells may be held in the battery cell carrier by an adhesive, and the at least one bus bar may include one or more adhesive insertion apertures for providing access to adhesive wells of the battery cell carrier configured to dispense the adhesive to the battery cells in the battery cell carrier.

When viewed in a direction orthogonal to the plane of the battery module, at least one bus bar may cover or the plurality of bus bars may together cover greater than 50%, greater than 60%, or greater than 70% of the surface area of the plurality of battery cells.

The plane of the battery module may be defined by the support, for example, where the support is planar. Viewing in a direction orthogonal to the plane may include viewing in a direction perpendicular to the first end of the battery cell.

According to a second aspect of the present invention, there is provided a battery pack including the battery module according to the first aspect of the present invention.

The battery pack may be used for an electric vehicle.

According to a third aspect of the present invention, there is provided an electric vehicle including the battery module according to the first aspect or the battery pack according to the second aspect.

Individual battery modules of a battery pack in an electric vehicle may be conveniently replaced, or may be separated from the battery pack for other purposes, such as installation in an industrial or home energy storage system.

Other features and advantages of the present invention will become apparent from the following description of examples thereof, which is made with reference to the accompanying drawings.

Drawings

In order that the invention may be more readily understood, embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

fig. 1 is a schematic diagram of a battery module arrangement in a battery pack according to an example;

fig. 2A is a schematic view of a battery module of the battery pack of claim 1, showing the battery cells, bus bars, and circuit board therein;

fig. 2B is a schematic side and plan view of the battery cell of fig. 2A;

FIG. 3A is a schematic view of a connector connecting the circuit board of FIG. 2A with a bus bar;

FIG. 3B is a schematic view of an alternative arrangement of the connector of FIG. 3A;

fig. 4A is a schematic isometric view of a battery cell carrier showing the bus bar of fig. 2A and a circuit board mounted thereon;

FIG. 4B is a cross-sectional side view of the battery cell carrier of FIG. 4A;

fig. 5 is a schematic plan view of a bus bar connected to a battery cell according to an example;

fig. 6 is a schematic isometric view of one of the bus bars of fig. 5, according to an example;

fig. 7 is a schematic plan view of a bus bar connected to a battery cell according to an example;

fig. 8A is a schematic side view of an electric vehicle according to an example; and

fig. 8B is a schematic plan view of the underside of the electric vehicle of fig. 8A.

Detailed Description

Details of methods and systems according to the examples will become apparent from the following description with reference to the accompanying drawings. In this specification, for purposes of explanation, numerous specific details of examples are set forth. Reference in the specification to "an example" or similar language means that a particular feature, structure, or characteristic described in connection with the example is included in at least one example, but not necessarily in other examples. It should also be noted that the examples shown in the figures are described in various different ways and are schematic representations, with certain features being omitted and/or necessarily simplified for ease of explanation and understanding of the concepts behind the examples.

Certain examples described herein relate to a battery module including a plurality of battery cells. The battery module may be part of a battery module arrangement forming at least part of a battery pack. Examples of the invention will be described in the context of an electric vehicle. It is to be understood that the invention is not limited to this purpose and may be applied to supply and/or store electrical energy for any kind of industrial, commercial or domestic purpose, for example in smart grids, home energy storage systems, power load balancing, etc.

Hereinafter, the terms "battery," "cell," and "battery cell" may be used interchangeably and may refer to any of a variety of different battery cell types and configurations, including but not limited to lithium-ion, lithium-ion polymer, nickel-metal hydride, nickel-cadmium, nickel-metal hydride, alkaline, or other battery cell types/configurations.

Fig. 1 shows a schematic diagram of a battery pack 10 including an arrangement of battery modules 100a-100c and a battery management system 200. The battery modules 100a-100c may be generally referred to herein using the reference numeral 100. The battery pack 10 has a first dimension 11 and a second dimension 12 corresponding to the width and length dimensions of the battery pack 10, respectively. The first and

second dimensions

11, 12 may alternatively be referred to as the "x" and "y" dimensions. A third dimension 13, also referred to herein as the "z" dimension, is orthogonal to the first and

second dimensions

11, 12 and corresponds to the depth or height dimension of the battery pack 10. In the example shown, the first dimension 11 is also a minor dimension of the battery pack 10 in the x-y plane. In other examples, the first dimension 11 may be a major dimension of the battery pack 10 in the x-y plane, or the battery pack 10 may be equilateral in the x and y dimensions. As used herein, the terms "major dimension" and "minor dimension" refer to the longest and shortest spans or lengths, respectively, of a structure. The major dimension is generally (as is the case herein) but not exclusively perpendicular to the minor dimension.

Three battery modules 100a-100c are shown in the battery pack 10, but in other examples, there may be any other number of battery modules 100 in the battery pack 10. The battery modules 100a-100c of the present example each include a plurality of battery cells (shown in fig. 2 a) arranged in a cell stack 110, collectively referred to herein as a "cell stack 110". Each of the battery modules 110a-100c of fig. 1 includes a respective support 120a-120c and four cell stacks 110 mounted on the respective support 120a-120 c.

Taking one battery module 100a as an example, the battery module 100a includes a first cell group 110a, a second cell group 110b, a third cell group 110c, and a fourth cell group 110 d. The support 120a of the battery module 100a is planar and includes opposing first and

second faces

121, 122. The cell stacks 110a-110d are arranged such that two

cell stacks

110a, 110b are mounted on a first face 121 of the support 120a with a spacing therebetween, and two

cell stacks

110c, 110d are mounted on a second face 122 of the support 120a with a spacing therebetween. As such, a first channel 123 is defined between the

cell stacks

110a, 110b on the first side 121, and a second channel 124 is defined between the cell stacks on the second side 122.

In the present example, each support 120a-120c is also shown as a generally regular rectangular plate-like member, including a major dimension and a minor dimension, and supporting a generally rectangular parallelepiped-shaped cell group 110a-110 d. In this way, the support is elongate. In some examples, the

channels

123, 124 of the battery modules 100a-100c extend in the minor dimension of the respective supports 120a-120 c. In some examples, any number of cell stacks 110a-110d may be mounted on support 120 a. In other examples, the cell stacks 110a-110d may be mounted on only one of the first and

second faces

121, 122. In some examples, each support 120a-120c may be a cooling member.

The battery modules 100a-100c are arranged side-by-side in the width direction in the battery pack 10 of fig. 1, adjacent to and coplanar with each other in the second dimension 12, such that the cell stacks 110a-110d of each battery module 100a-100c are aligned with the corresponding cell stacks 110a-110d of each other battery module 100a-100 c. It should be understood that the term "coplanar" as used herein includes slight deviations from a plane in the location of elements. That is, in some examples, one or more battery modules 100a-100c may be located slightly above or below the plane of the battery pack 10, such as at a distance of two or five times the average thickness of one or each support 120a-120c above or below the plane defined by the one or more supports 120a-120 c. In the latter example with respect to bus bars (not shown in fig. 1), the term "coplanar" may be defined in a similar manner with respect to the average thickness of the bus bars, rather than with respect to the average thickness of the supports 120a-120 c.

As shown in the example of FIG. 1, the first and

second channels

123, 124 of each battery module 100a-100c in the example of FIG. 1 are longitudinally aligned with the corresponding first and

second channels

123, 124 of each other battery module 100a-100 c. The alignment of the first channels 123 forms first longitudinal channels 14 between the

cell stacks

110a, 110b in the battery pack 10, and the alignment of the second channels 124 forms second longitudinal channels 15 between the cell stacks 110c, 110d in the battery pack 10. There may be more than two

longitudinal channels

14, 15 or only one longitudinal channel in the battery 10. In other examples, the

longitudinal channels

14, 15 may not be present in the battery pack 10. According to the present example, the first and second

longitudinal channels

14, 15 extend parallel to the second dimension 12 of the battery pack 10.

In the example shown, the battery modules 100a-100c are spaced along the second dimension 12 of the battery pack 10 to form a plurality of transverse channels 16 in the battery pack 10. The cross channels 16 of the illustrated example extend in the first dimension 11 of the battery pack 10.

The battery management system 200 of the present example includes a controller 210. Controller 210 is communicatively coupled to each cell stack 110 in each battery module 220 via communication lines 220. In some examples, the communication line 220 includes a wire. In other examples, the communication line 220 includes a bus bar. In other examples, communication between the controller 210 and the cell stack 110 may alternatively or additionally be wireless. The battery modules 100a-100c are electrically connected to each other and to the controller 210 through the module connection member 221. That is, the cell group 110 of each battery module 100 is connected to the cell group 110 of the adjacent battery module 100 via the module connection member 221. In this example, the module connectors 221 between the cell stacks 110 of adjacent battery modules 100 are located in the respective transverse channels 16.

According to the illustrated example, each cell stack 110 is connected in series with other cell stacks 110 in the same row such that the total current flows in the second major dimension 12 of the battery 10. Each cell stack 110a-110d in battery module 100a is electrically isolated from the other cell stacks 110a-110d on the same support 120a, at least until battery module 100a is connected to the

other battery modules

100b, 100c in battery pack 10. For example, the

cell stacks

110a, 110b on the first face 121 of the support 120a at the end of the battery pack 10 in the second dimension 12 are connected to the cell stacks 110c, 110d on the second face 122 of the support 120 a. The cell stacks 110a, 110c are electrically isolated from the

adjacent cell stacks

110b, 110d on the same support 120a by the

respective channels

123, 124 and/or

longitudinal channels

14, 15.

In some examples, the controller 210 of the battery management system 200 is configured to change the electrical output of the battery pack 10, and/or reconfigure the battery pack 10. In some examples, the battery modules 100a-100c are electrically connected to a controller other than the controller 210 shown in fig. 1. In the present example, the controller 210 is configured to detect and/or monitor one or more characteristics of the cell stack 110 of each battery module 100a-100c, as will be described below with reference to fig. 2.

Fig. 2A shows a simplified schematic of the cell stack 110 of one of the battery modules 100a-100c of fig. 1, illustrating the battery cells 130 in the cell stack 110. The cell stack 110 includes a plurality of battery cells 130 arranged in a two-dimensional array 140. The array 140 has a major dimension parallel to the x-axis and a minor dimension parallel to the y-axis. The battery cells 130 in the array 140 are arranged in a plurality of banks (or sub-banks) 150a-150e of battery cells 130. For clarity, the

banks

150b, 150d of the battery cells 130 in fig. 2A are filled in white, and the

banks

150a, 150c, 150e are filled in shading to distinguish the banks 150a-150e of the battery cells 130. The banks 150a-150e may be generally referred to herein using the reference numeral 150.

The example shown in fig. 2A shows five banks 150a-150e of battery cells 130 connected in parallel, each bank 150a-150e including eight or nine battery cells 130. In other examples, there may be any number of such banks 150a-150e and any number of cells 130 in each bank 150a-150 e. Furthermore, in the present example, the battery cells 130 are arranged in rows that extend in a major dimension of the array 140. The banks 150a-150e span the length of the cell stack 110 in the major dimension, and each bank 150a-150e is limited to a single bank in the array 140. As shown, each bank 150a-150e is generally a one-dimensional rectangular array. It should be understood that in other examples, each row group 150a-150e of parallel-connected battery cells 130 may not span the entire length of the cell stack 110 in its major dimension, and/or the row groups 150a-150e may span multiple rows in the array 140, and/or may not be limited to such a row or rectangular array. That is, in other examples, each of the row groups 150a-150e includes two or more rows of battery cells.

Fig. 2B shows a side view and a plan view of the battery cell 130. The battery cell 130 includes a first end 131 and a second end 132 opposite the first end 131. In this example, the second end 132 of each battery cell 130 in the stack 110 is secured to the

faces

121, 122 of the respective supports 120a-120c, whereby the first ends 131 of the battery cells 130 are substantially coplanar, lying in a plane parallel to the plane of the respective supports 120a-120 c.

The battery cells 130 of the present example each include battery cell terminals of a first polarity 133 and a second polarity 134 at respective first ends 131, the first polarity terminal 133 and the second polarity terminal 134 having opposite polarities. The

cell terminals

133, 134 of each cell 130 are exposed at the first end 131 of the cell 130, away from the respective support 120a-120 c. In this example, the first polarity terminal 133 is a positive terminal 133 of the battery cell 130, and the second polarity terminal 134 is a negative terminal 134 of the battery cell 130. It should be understood that in other examples, the polarity of the

battery cell terminals

133, 134 may be reversed.

In this example, for each battery cell 130, the positive terminal 133 includes a central protrusion 133 on the first end 131 of the battery cell 130 and the negative terminal 134 includes an annular portion 134 on the first end 131 of the battery cell 130 surrounding the central protrusion 133. The annular portion 133 is defined by a rim or edge of the housing or can of the battery cell 130. It will be understood that the positive and

negative cell terminals

133, 134 of the cell 130 of the present invention are not limited to this shape, but may be any other shape suitable to facilitate connection to the positive and negative electrodes, respectively, of the cell 130.

According to the present example, the battery cells 130 of the battery cell stack 110 are mounted on the respective supports 120a-120c by any method, including but not limited to using an adhesive, a securing mechanism, such as a clasp, a clamp, a bracket, or any other suitable attachment mechanism. The battery cells 130 are supported at respective second ends 132 in a tray (not shown in fig. 2B). The tray includes a plurality of recesses in each of which the second end 132 of a respective battery cell 130 is received. The trays are mounted to respective supports 120a-120 c. In other examples, a tray may not be present and the respective supports 120a-120c may be formed to receive the battery cells 130. That is, the respective support 120a-120c may have at least one recess in which the battery cell 130 or the cell stack 110 is received and mounted.

According to the present example, the supports 120a-120c are constructed of an electrically conductive material, and the battery cell 130 is electrically insulated from the supports 120a-120c by a tray constructed of an electrically insulating material. In this example, the tray is thermally conductive. In other examples, the tray may be thermally insulated. In other examples, supports 120a-120c may be electrically non-conductive.

Returning to fig. 2A, the cell stack 110 of the illustrated example includes a plurality of bus bars 160, and in particular four bus bars 160a-160 d. We refer herein generally to reference numeral 160 as any one or more of the bus bars 160a-160 d. Each bus bar 160 electrically connects the battery cells 130 in at least one bank of battery cells 150a-150e in parallel. Thus, the bus bars 160 extend in a major dimension of the cell stack 110. The bus bars 160 further connect adjacent banks 150a-150e of parallel-connected battery cells together in series. In other examples, there may be any number of bus bars 160, such as more or less than four, such as only one bus bar 160. In this example, each bus bar 160 is an elongated conductive wire, plate or rod having connections (not shown in detail) to the positive or

negative cell terminals

133, 134 of the cells 130 in the banks 150a-150 e.

More specifically, one bus bar 160a in the illustrated example is configured to connect the positive cell terminal 133 of each cell 130 in one bank 150a of cells 130 to the negative cell terminal 134 of each cell 130 in an adjacent bank 150b of cells 130. In some examples, the bus bars 160 on the periphery of the cell stack 110 (not shown in fig. 2A) are configured to connect the battery cells 130 of the respective

peripheral banks

150a, 150e of battery cells 130 in parallel with one another. In some examples, the peripheral bus bars 160 are configured to facilitate connection between the cell groups 110 of adjacent battery modules 100, such as via module connections 221.

In the example shown, the banks 150a-150e of battery cells 130 are connected such that current flows in series between the banks 150a-150e in the minor dimension of the cell stack 110 via the bus bars 160, as indicated by the arrows labeled I in fig. 2A. Thus, the current flow in the cell stack 110 is generally perpendicular to the major dimension of each bus bar 160, which bus bar 160 is elongated and extends in the major dimension of the cell stack 110. In other words, the total current in the cell stack 110 is evenly distributed over the major dimension of the cell stack 110. This direction is referred to as "overall" or "on average" because there may be some minor deviations in the direction of current flow, which may be determined, for example, by the particular arrangement of the battery cells 130 and/or the shape of the bus bars 160 connecting the battery cells 130, as will be described below with reference to fig. 4-5.

Having elongated bus bars 160 that span the major dimension of the cell stack 110 while having total current distributed across the minor dimension of the cell stack 110 enables the thickness of the bus bars 160 to be reduced (as compared to bus bars 160 having total current that spans the minor dimension and flows in the major dimension) while maintaining a desired cross-sectional area and current density. The illustrated example includes a cell stack 110 having an aspect ratio of approximately 3:1 (i.e., having a major dimension that is three times longer than a minor dimension). Thus, the cell stack 110 may include bus bars 160 that are approximately three times thinner than those required for a cell stack 110 having a 1:1 aspect ratio, while providing the same current density in the bus bars 160. Thus, the bus bars 160 may be thinner and lighter per unit area, which means that they require less space per unit area and may be more easily formed, for example, for the purpose of connecting to the

terminals

133, 134 of a single battery cell 130. Furthermore, a shorter overall current path in the cell stack 110 may result in a reduction in resistance in the bus bar 160, as resistance is proportional to the length of the current path.

The battery management system 200 includes a circuit board 230, shown in fig. 2A, connected to the bus bars 160a-160d of the cell stack 110 via respective bus bar tabs 161a-161 d. That is, each bus bar 160a-160d includes a respective tab 161a-161d extending from the bus bar 160a-160d, and the tabs 161a-161d are electrically connected to the circuit board 230. The tabs 161a-161d are located at the ends of the bus bars 160a-160d and extend from the bus bars 160a-160d in a direction orthogonal to the direction of total current flow in the bus bars 160a-160 d. That is, each tab 161a-161d is a longitudinal extension of the respective bus bar 160a-160d in a first direction, and current flows in a second direction orthogonal to the first direction. One or more bus bar tabs 161a-161d may be generally referred to herein using reference numeral 161.

Each tab 161a-161d is disposed in the same plane as the respective bus bar 160a-160d, and thus lies in the same plane as the total current flowing through the respective bus bar 160a-160 d. In other examples, the tabs 161a-161d may be disposed in offset planes and parallel to the total current flowing through the respective bus bars 160a-160 d. In yet another example, the tabs 161a-161d may be located on a central portion of the bus bars 160a-160d, distal from the ends of the bus bars 160a-160 d. In some examples, the tabs 161a-161d are upstanding.

In this example, the tabs 161a-161d of each bus bar 160a-160d in each cell stack 110 in the battery pack 10 extend into the

respective channels

123, 124 defined between the cell stack 110 and the adjacent cell stack 110. The circuit boards 230 connected to the bus bars 160a-160d are then conveniently located in the

channels

123, 124 and thus in the

longitudinal channels

14, 15 of the battery pack 10.

The circuit board 230 of this example includes apertures 231a-231d (generally referred to herein as "apertures 231") through each of which passes a respective bus bar tab 161a-161 d. Fig. 3A shows a side view of the bus bar tab 161 through the aperture 231 of the circuit board 230. The bus bar tab 161 is secured to the circuit board 230 by a clip 232, the clip 232 being located on a side of the circuit board 230 that extends away from the tab 161 from the bus bar 160. In other examples, the clip 232 may be located on the same side of the circuit board 230 as the bus bar 160. In this example, the clip 232 electrically connects the circuit board 230 to the tab 161. In this way, the voltage in the respective bus bar 160 can be detected via the tab 161 and the circuit board 230. In other examples, the clip 232 may be electrically insulating.

Fig. 3B shows a circuit board 230 connected to a bus bar tab 161 in an alternative arrangement according to another example. In this example, the circuit board 230 does not include apertures 231 for receiving the respective bus bar tabs 161a-161 d. Rather, the bus bar tabs 161 extend toward the circuit board 230 and are secured to the circuit board 230 by respective clips 232 on the same side of the circuit board 230 as the tabs 161.

Although not shown in fig. 2A, circuit board 230 includes a plurality of clips 232, each configured to connect to a respective tab 161a-161 d. The clips 232 provide a secure, yet conveniently detachable connection between the circuit board 230 and the corresponding bus bar tabs 161.

Returning to fig. 2A, the battery management system 200 is configured to detect and/or monitor one or more properties of the bus bars 160a-160d, for example, to monitor the performance of the respective cell stack 110 and/or battery modules 100a-100c of fig. 1. In this example, the battery management system 200 includes a plurality of circuit boards 230, each of which is connected to a respective cell stack 110 in the battery pack 10. In other examples, there may be any number of circuit boards 230, for example, to monitor characteristics of any number of cell stacks 110 and/or battery modules 100a-100 c.

As described above, the circuit board 230 connected to the cell stack 110 of fig. 2A includes clips 232 that are electrically connected to the respective bus bars 160. The battery management system 200 of the present example is configured to detect the voltage of each of the bus bars 160a-160d in the cell stack 110 via the respective bus bar tabs 161a-161d, clips 232, and circuit board 230. As such, circuit board 230 includes a voltage sensor at least partially defined by clip 232. In some examples, the controller 210 of the battery management system 200 determines and/or monitors the integrity or performance of the bus bars 160a-160d or the battery cells 130 connected thereto based on the sensed voltage. In other examples, the controller 210 determines and/or monitors the output of the respective cell group 110 based on the sensed voltage.

The circuit board 230 includes sensors for detecting characteristics of the respective bus bars 160a-160 d. In this example, the circuit board 230 includes a plurality of temperature sensors 233a-233d, such as thermistors, each temperature sensor 233a-233d configured to sense a temperature of a respective bus bar 160a-160d via a respective tab 161a-161 d. In some examples, the circuit board 230 includes a single temperature sensor 233a-233d configured to detect the temperature of one or more of the bus bars 160a-160 d. In the example shown, the temperature sensors 233a-233d are located proximate to the tabs 161a-161d of the respective bus bars 160a-160 d. In this way, the accuracy of the temperature sensed in the region of the tabs 161a-161d may be improved. In some examples, the controller 210 of the battery management system 200 determines and/or monitors the integrity of the bus bars based on the sensed temperature. In other examples, the controller 210 monitors and/or controls operation of the cooling system via a feedback loop based on the sensed temperature.

Thus, the battery management system 200 of the present example is configured to detect and/or monitor one or more properties of the bus bars 160 in the battery pack 10, for example, to monitor the performance of the individual battery modules 100a-100 c. As previously described, the amount of current flowing in the major dimension of each of the bus bars 160a-160e of the cell stack 110 decreases. In this manner, fluctuations in the signals indicative of the properties sensed by the circuit board 230 via the tabs 161a-161d are minimized, thereby improving the reliability of the battery management system 200 in detecting the properties (e.g., voltage) of the bus bars 160a-160 d.

In the example shown, the total current flows in each row of the cell stack 110 along a major dimension of the battery pack 10. The battery modules 100a-100c are connected such that the total current in each row flows in the opposite direction to each adjacent row and the upper and lower rows. The magnetic field (not shown in the figure) is generated by the total current flow in each row. Due to the different direction of the total current, the magnetic field generated in each row is of opposite polarity to the magnetic field generated in each adjacent row and the upper and lower rows. Thus, the magnetic field of each row interacts with the magnetic fields of the other rows in the region of the

channels

123, 124 and the

longitudinal channels

14, 15. The interacting magnetic fields at least partially cancel each other out, resulting in a field-weakening zone in each

channel

123, 124 and

longitudinal channel

14, 15.

In the example shown, each circuit board 230 in the battery pack 10 is located in a

channel

123, 124 and a

longitudinal channel

14, 15. In this manner, each circuit board 230 and/or other electronic or electrical component located within the

longitudinal channels

14, 15 experiences reduced magnetic interference. This may improve the reliability of the sensing of the circuit board 230 and improve the performance of the battery management system 200 as a whole.

In this example, the battery cells 130 in the cell stack 110 are supported at a first end 131 by a battery cell carrier. Fig. 4A shows a schematic isometric view and fig. 4B shows a cross-sectional view of a portion of a cell stack 110 showing a simplified cell carrier 300. The battery cell carrier 300 includes a plurality of carrier apertures 310, each carrier aperture 310 supporting a battery cell 130 and configured to allow access to a respective

battery cell terminal

133, 134. The battery cell carrier 300 includes bus bar mounting features in the form of bus bar mounting protrusions 320 for mounting the bus bars 160. The bus bar 160 includes corresponding mounting features in the form of bus bar mounting apertures 169 for receiving bus bar mounting projections, as will be described in more detail below with reference to fig. 6. The bus bar mounting protrusions 320 each include a deformed region 321 for fixing the bus bar 160 to the battery cell carrier 300.

The battery cell carrier 300 includes circuit board mounting features in the form of circuit board mounting protrusions 330 for mounting the circuit board 230. Circuit board 230 includes corresponding circuit board mounting features in the form of circuit board mounting apertures 234 for receiving circuit board mounting protrusions 330 from battery cell carrier 300. In this manner, the circuit board mounting projections provide structural support for the circuit board 230. The circuit board 230 of the present example is planar and mounted orthogonal to the plane of the cell stack 110, tabs 161, and/or bus bars 160.

Fig. 5 shows a schematic top view of at least a portion of a cell stack 110 according to an example. For ease of understanding, features of the cell stack 110 that are similar to features of the previous examples have been given the same reference numerals. The cell stack 110 includes a plurality of battery cells 130 arranged in six banks 150a-150f of battery cells 130 on a support 120 (not shown). The battery cells 130 are arranged in rows on the support, and each row group 150a-150f includes cells in two rows. In other examples, each row group 150a-150f may include more than two rows or cells in a single row.

The battery cells 130 in each bank 150a-150f are electrically connected in parallel, and the banks 150a-150f are electrically connected in series by a plurality of bus bars 160, in this case five bus bars 160a-160 e. In other examples, there may be more than six or less than six battery cell row groups 150, and/or more than five or less than five bus bars 160. Adjacent bus bars 160a-160e in fig. 5 are hatched in different directions to help distinguish the bus bars 160a-160 e. The

lower cell terminals

133, 134 are shown with solid lines. Fig. 6 shows a schematic isometric view of a portion of one of the bus bars 160a-160e of fig. 5.

The battery cells 130 of the example shown in fig. 5 are arranged in a rectangular array 140, as described above with reference to the example shown in fig. 2A. For clarity, fig. 5 shows only a subset of the battery cells 130 in the cell stack 110. The battery cell stack 110 of the present example includes additional battery cells 130, not shown, arranged in the x-direction. Thus, the major dimension of the cell stack 110 and the bus bars 160a-160e contained therein is parallel to the x-direction. Furthermore, the banks 150a-150f and the battery cells 130 included therein are electrically connected to each other via the bus bars 160a-160e in the same manner as described above with reference to fig. 2A-3B. That is, the bus bars 160a-160e are connected to the battery cells 130 such that the total current flows in the minor dimension of the cell stack 110, parallel to the y-direction.

Referring to fig. 5 in more detail, the bus bars 160a to 160e each include a ridge 162, a positive connection portion 163a extending from a first side of the ridge 162, and a negative connection portion 163b extending from a second opposite side of the ridge 162. The positive electrode connection part 163a of one bus bar 160a is connected to the positive electrode terminal 133 of the battery unit 130 in a different row of one bank 150a of the battery unit 130, and the negative electrode connection part 163b is connected to the negative electrode terminal 134 of the battery unit 130 in a different row of another adjacent bank 150b of the battery unit 130. In this manner, the bus bar 160a is configured to electrically connect the positive terminals 133 of the battery cells 130 in one row group 150a of the battery cells 130 in parallel, and electrically connect the negative terminals 134 of the battery cells 130 in an adjacent row group 150b of the battery cells 130 in parallel, and electrically connect the first row group 150a and the second row group 150b in series. Ridge 162 includes a tab 161 as described above.

In the illustrated example, the first ends 131 of the battery cells 130 are coplanar, the positive and

negative connection portions

163a, 163b of each bus bar 160 are coplanar, and the ridge 162 of each bus bar 160 is in a plane parallel to the

connection portions

163a, 163b and spaced above the

connection portions

163a, 163 b. As such, the cell group 110 includes a single layer of bus bars 160 such that the

connection portions

163a, 163b of each bus bar 160 are coplanar with the

connection portions

163a, 163b of each other bus bar 160, and the ridge 162 of each bus bar 160 is coplanar with the ridge 162 of each other bus bar 160.

According to the example shown in fig. 5, the positive and negative

electrode connecting portions

163a, 163b of adjacent bus bars 160a-160e are shaped to be spaced apart from each other and conform to the shape of each other. A gap is maintained between the positive and negative

electrode connecting portions

163a, 163b of adjacent bus bars 160a-160e to maintain electrical isolation between the bus bars 160a-160e, thereby preventing short circuits.

According to the example shown in fig. 5, the positive and

negative connection portions

163a, 163b of each bus bar 160a-160e each include a respective plurality of positive and negative

lateral projections

164a, 164b, which are disposed along the first and second sides of the ridge 162, respectively. As such, each positive and negative

lateral projection

164a, 164b forms a resilient cantilever extending from the spine 162, e.g., to facilitate connection of the

lateral projections

164a, 164b to the respective

battery cell terminals

133, 134. The positive and negative

lateral projections

164a, 164b of adjacent bus bars 160b are staggered with respect to each other.

According to the illustrated example, each bus bar 160a-160e includes a positive transverse projection 164a and a negative transverse projection 163b of different shapes. For example, one of the bus bars 160a of the example shown in fig. 5 includes four positive lateral projections 164a, two of which are generally Y-shaped, and two of which simply extend orthogonally from the ridge 162. The negative electrode connecting portion 163b of one of the bus bars 160c similarly includes negative electrode lateral protrusions 164b different in shape from each other, and is different in shape from the lateral protrusions of the other bus bars 160a to 160 e. The pattern of positive and negative

lateral projections

164a, 164b repeats along the ridge 162 of the respective bus bars 160a-160 e. It should be understood that the shape and pattern of the positive and negative

electrode connecting portions

163a, 163b are not limited to those presented in the example of fig. 5. In other examples, the positive lateral protrusions 164a and the negative lateral protrusions 164b may have any other suitable shape and/or pattern.

According to the example shown in fig. 5, each positive lateral projection 164a comprises one or more positive contacts 165a for electrically connecting to the positive terminal 133 of a respective one or more battery cells 130, and each negative lateral projection 164b comprises a plurality of negative contacts 165b for electrically connecting to the negative terminal 134 of a respective at least one other battery cell 130. In this example, some of the positive lateral projections 164a include two or more positive contacts 165a that are connected to the positive terminals 133 of the respective two or more battery cells 130. Further, each negative lateral projection 164b includes at least two negative contacts 165b for connecting to the negative terminals 134 of a respective at least two other battery cells 130. In the present example, as shown in fig. 5, several of the positive and negative

lateral protrusions

164a, 164b are connected to the battery cells 130 in different rows, while the other lateral protrusions are connected to the battery cells 130 in the same row.

According to the present example, the positive contacts 165a are suitably shaped and arranged to electrically connect the corresponding positive lateral projections 164a to the respective battery cells 130. The negative contact 165b is suitably shaped and arranged to electrically connect the corresponding negative lateral projection 164b to the corresponding battery cell 130. In this example, the plurality of positive electrode contacts 165a includes a circular portion when viewed in a direction orthogonal to the plane of the bus bars 160a-160e, each positive electrode contact 165a conforming to the shape of the positive electrode terminal 133 of a respective battery cell 130. Similarly, the plurality of negative contacts 165b includes a semi-annular portion when viewed in a direction orthogonal to the plane of the bus bars 160a-160e, each negative contact 165b conforming to the shape of the negative terminal 134 of a respective battery cell 130. In some examples, any number of positive contacts 165a and negative contacts 165b of the bus bars 160a-160e are so shaped.

According to the example shown, each bus bar 160a-160e includes the same number of positive contacts 165a as negative contacts 165 b. That is, the bus bars 160a-160e each include an equal number of connections in total on opposite sides of the ridge 162. For example, each bus bar 160a-160e is shown in fig. 5 as being connected to the negative terminals 134 of eight battery cells 130 on one side of the ridge 132 and to the positive terminals 133 of eight other battery cells 130 on the opposite side of the ridge 162. In this way, current flows from the positive electrode connecting portion 163a to the negative electrode connecting portion 163b through the ridge 162.

In this example, the connections in each bus bar are evenly distributed on either side of the ridge 126, such that current is evenly distributed along the length of each bus bar 160a-160e in the x-direction, thereby reducing the amount of current flowing along the ridge 126 in the x-direction. In this way, the accuracy of the sensed characteristics at the tab 161 at the end of each ridge 162 may be improved. In other examples, the connections may be distributed unevenly on either side of ridge 162. In other examples, there may be an unequal total number of connections on either side of ridge 162.

In this example, positive and

negative contacts

165a, 165b are welded to the

respective cell terminals

133, 134 to maintain electrical contact between the bus bars 160a-160e and the underlying cell 130. As best shown in fig. 6, the positive contacts 165a each include a weld aperture 166 therethrough, with at least a portion of the weld being visible through the weld aperture 166. In other examples, the negative contact 165b may also include a weld aperture through which at least a portion of the weld may be seen. In other examples, such weld apertures may not be present on the positive or

negative contacts

165a, 165 b. In other examples, the positive and

negative contacts

165a, 165b may be connected to the respective

battery cell terminals

133, 134 by any other suitable means, such as by using mechanical connectors, adhesives, or magnetic securing devices.

The ridges 162 of each of the bus bars 160a-160e are configured to bridge the

underlying cell terminals

133, 134. In other words, as best shown in fig. 6, the ridge 162 of each bus bar 160 is located above and spaced apart from the

underlying cell terminals

133, 134 such that the ridge 162 does not contact the

cell terminals

133, 134. That is, the first ends 131 of the battery cells 130 are coplanar, the positive connection part 163a and the negative connection part 163b are coplanar and connected to the battery cells 130, and the ridge 162 is located in a plane parallel to the

connection parts

163a, 163b and spaced above the

connection parts

163a, 163 b.

Further, in the illustrated example, the positive and

negative connection portions

163a, 163b of each bus bar 160 include respective positive and

negative bridge portions

167a, 167b, each positive and

negative bridge portion

167a, 167b extending over and spaced apart from the

underlying cell terminal

133, 134. That is, the first end 131 of the battery cell 130 and the positive and

negative contacts

165a, 165b lie in a first plane, while the ridge 162 lies in a second plane that is parallel to and spaced above the first plane. The positive and

negative bridge portions

167a, 167b then extend from the respective positive and

negative contacts

165a, 165b in the first plane towards the second plane. In some examples, the

bridge portions

167a, 167b extend to or above the second plane.

In the example shown, each negative bridge portion 167b connects a negative contact 165b of the negative lateral projection 164b to the ridge 162, while some positive bridge portions 167a connect a positive contact 165a of the positive lateral projection 164a to the ridge 162, and some positive bridge portions 167a form part of the positive lateral projection 164a itself. As such, some positive bridge sections 167a provide a bridge between two or more positive contacts 165a of the positive connection section 163 a. In other words, the at least one positive bridge portion 167a is configured to connect the positive terminal 133 of one battery cell 130 to the positive terminal 133 of another battery cell 130 in the same row group 150 of battery cells 130 connected in parallel. In other examples, the one or more negative lateral projections 164b include a negative bridge portion 167b connecting two or more negative contacts 165b of a respective negative lateral projection 164 b.

The bus bars 160 of the present example include bus bar mounting apertures 169 that engage the bus bar mounting protrusions 320 of the battery cell carrier 300, as described above with reference to fig. 4A and 4B. This is to align the positive and

negative contacts

165a, 165b of each bus bar 160 with the respective battery cells 130. Fig. 6 shows the bus bar mounting apertures 169 of the bus bars 160 in more detail. In this example, the battery cells 130 are held in the battery cell carrier by an adhesive, and the bus bar 160 includes one or more adhesive insertion apertures 170 for providing access to adhesive wells of the battery cell carrier that are configured to dispense adhesive to the battery cells 130 in the battery cells.

Fig. 7 shows a portion of an alternative arrangement of two

bus bars

160a, 160b according to an example. For ease of understanding, features of the cell stack 110 that are similar to features of the previous examples have been given the same reference numerals. The cell stack 110 shown in fig. 7 includes at least one bus bar 160a, the bus bar 160a including a generally straight elongated ridge 162, and at least one other bus bar 160b, including a curved ridge 168. When viewed in the z-direction, the straight ridge 162 extends parallel to and between two adjacent rows of battery cells 130. Curved ridge 168 includes a first length 168a and a second length 168b, the first length 168a extending parallel to and between the first pair of battery cell rows 130, the second length 168b offset from the first length 168a, and the second length 168b extending parallel to and between the second pair of battery cell rows 130. In other examples, straight ridges 162 may be aligned on a single row of cells 130. In other examples, the first length 168a of the curved ridge 168 may be aligned on a first row of cells 130 and the second length 168 of the curved ridge 168 may be offset from the first portion 168a and aligned on a second row of cells 130, or parallel to and between a pair of rows of cells.

In the example shown in fig. 7, the cell stack 110 includes a dummy area 180 where no battery cells 130 are present in the array 140. The bus bar 160 is shaped to conform to the virtual area 180, for example, such that the bus bar 160 does not contact and/or cover the virtual area 180. In some examples, the battery cell carrier 300 includes virtual apertures corresponding to the respective virtual areas 180. In such examples, the virtual aperture may obstruct the battery cell 130 from passing therethrough. In other examples, the virtual aperture is configured to receive an adhesive. In this manner, the same adhesive flow rate may be provided for each cell carrier aperture, thereby improving the ease of manufacturing of the battery modules 100a-100 e. In other examples, the virtual area 180 is used to check the quality of the manufactured product, for example to check whether a given amount of adhesive is consistently provided during manufacturing.

In each of the examples described above with reference to fig. 2A-6, each cell group 110, and therefore each battery module 100a-100c, includes at least two bus bars 160 having the same form. In other examples, any number of bus bars 160 have the same form. In other examples, none of the bus bars 160 have the same form.

In each of the examples described above, the bus bars 160 together cover greater than 70% of the surface area of the plurality of battery cells 130 in the cell stack 110 when viewed in a direction orthogonal to the plane of the cell stack 110. In other examples, the bus bars 160 together cover greater than 50% or greater than 60% of the surface area of the plurality of battery cells 130 in the cell stack 110.

In some examples, the battery pack 10 and/or the battery module 100 as described above are adapted for use in an electric vehicle 1. Fig. 8A shows a schematic side view of an electric vehicle 20, the electric vehicle 20 including a battery pack 10 arranged in the electric vehicle 20. The battery pack 10 may be disposed toward the lower side of the electric vehicle 20, for example, so as to lower the center of mass of the electric vehicle 20.

Fig. 8B shows a schematic plan view of the underside of the electric vehicle 20. The electric vehicle 20 comprises a front electric drive unit 21 and a rear electric drive unit 22 for powering drive wheels 23 of the electric vehicle 20. The battery pack 10 is located between the front and rear

electric drive units

21, 22. In this example, the front and rear

electric drive units

21, 22 each include an inverter for converting the DC battery current to AC current for delivery to the traction motors. In other examples, an inverter is not required.

In the example shown, the battery pack 10 includes an electrical connection 24 for connecting the battery pack 10 to the rear electric drive unit 22. The electrical connections 24 extend along at least one of the

longitudinal channels

14, 15 of the battery 10. In some examples, battery pack 10 is arranged such that battery input/output 25 is positioned toward front electric drive unit 21 of the electric vehicle, and electrical connections 24 extend from battery input/output 25 along

longitudinal channels

14, 15 to rear electric drive unit 22. The electrical connections are connected to an inverter of the rear electric drive unit. In some examples, the electrical connections connecting the input/output 25 of the battery pack 10 to the front electric drive unit 21 or the charging port of the electric vehicle 20 extend along the

longitudinal channels

14, 15 of the battery pack 10.

In this example, the battery input/output 25 is part of a battery management system 200. In some examples, the battery input/output 25 is the controller 210. In some examples, the battery input/output 25 is located anywhere else on the battery pack 10, such as toward the rear electric drive unit 22 of the electric vehicle 10.

In the example shown in fig. 8B, the battery pack 10 includes eight battery modules 100, each of which includes four cell groups 110. In some examples, there may be more or less than eight battery modules 100 in the battery pack 10, and/or more or less than four cell stacks 110 in the battery modules 100.

In the present example, the battery pack 10 may be configured to operate at 400 volts (V) or 800 volts. Operating the battery pack 10 at a particular voltage may include charging or delivering energy at that voltage. It should be understood that in some examples, the battery pack 10 and the overall current path or circuitry included therein may be configured to operate at voltages other than those described. For example, a battery pack 10 configured for a home energy storage system may operate at a voltage below 400V, while a battery pack 10 configured for industrial use may operate at a voltage above 800V.

Although not shown in the figures, in one example, one or more bus bars 160 as described in any of the above examples are fabricated according to a method, for example, for use in a battery module 100, battery pack 10, or electric vehicle 20 according to any of the above examples. The method comprises the following steps: providing a sheet of conductive material, such as copper; providing at least one tool, such as a mold, for forming the electrically conductive material, the tool conforming to the shape of the one or more bus bars 160; and stamping one or more bus bars 160 from the sheet of conductive material using at least one tool. The method may further include cutting the one or more bus bars 160 from the sheet of conductive material, for example using a tool, for example after or during stamping of the one or more bus bars 160.

The above examples are to be understood as illustrative examples of the invention. Other examples of the invention are envisaged. For example, the battery pack 10 or battery module 100 may alternatively be used to provide and store electrical energy for any kind of industrial, commercial or domestic purpose, such as for energy storage and delivery in smart grids, home energy storage systems, electrical load balancing, and the like. The battery pack 10 may include any number of battery modules 100 and the cell stack 110 may include any number of battery cells 130.

It should be noted that the term "or" as used herein should be construed to mean "and/or" unless expressly stated otherwise.

It is to be understood that any feature described in relation to any one example may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other example, or any combination of other examples. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

Claims

1. A battery module comprising a support, a plurality of battery cells arranged in rows on the support, and at least one bus bar electrically connecting the battery cells to form a plurality of row groups of battery cells connected in parallel, each row group including battery cells in at least two rows, and the at least one bus bar comprising:

a ridge portion;

a positive electrode connection part extending from a first side of the spine and connected to positive electrode terminals of at least two battery cells in different rows of a first row group of battery cells connected in parallel; and

a negative electrode connection portion extending from a second opposite side of the ridge and connected to negative terminals of at least two battery cells in different rows of a second row group of battery cells connected in parallel.

2. The battery module of claim 1, wherein the battery module comprises at least one bus bar comprising a substantially straight elongated ridge and at least one other bus bar comprising a curved ridge.

3. The battery module of claim 1 or 2, wherein the ridge of the at least one bus bar is configured to bridge an underlying cell terminal.

4. The battery module of any of the preceding claims, wherein each battery cell comprises a first end and a second end, wherein the first end comprises a positive terminal and a negative terminal of the battery cell and the second end is mounted to a support.

5. The battery module of claim 4, wherein the first ends of the battery cells are coplanar, the positive and negative connection portions are coplanar, and the ridge is in a plane parallel to and spaced above the connection portions.

6. The battery module of claim 4 or 5, wherein, for each battery cell, the positive terminal comprises one of a central protrusion on a first end of the battery cell and an annular portion on the first end of the battery cell, the annular portion concentric about the central protrusion, and the negative terminal comprises the other of the central protrusion and the annular portion.

7. The battery module of any of the preceding claims, wherein the battery module comprises a plurality of bus bars, and each battery cell is connected to a positive connection portion of a first bus bar and a negative connection portion of a second bus bar adjacent to the first bus bar, and wherein the positive connection portion of the first bus bar and the negative connection portion of the second bus bar are mutually shaped to be spaced from and conform to each other for respective positive and negative connections to each battery cell.

8. The battery module of any of the preceding claims, wherein the battery module comprises a single layer of bus bars, the connecting portion of each bus bar being coplanar with the connecting portion of each other bus bar, and the spine of each bus bar being coplanar with the spine of each other bus bar.

9. The battery module of any of the preceding claims, wherein the positive and negative connection portions each comprise respective one or more positive and negative lateral projections arranged along respective first and second sides of the spine.

10. The battery module of claim 9, wherein the at least one bus bar comprises positive and negative lateral protrusions of different shapes.

11. The battery module of claim 9 or 10, wherein the at least one bus bar comprises a repeating pattern of positive and negative lateral projections along the spine.

12. The battery module of any of claims 9-11, wherein the battery module comprises a plurality of bus bars, and wherein positive lateral projections of a first bus bar are interleaved with negative lateral projections of an adjacent second bus bar.

13. The battery module of any of claims 9 to 12, wherein each positive lateral projection comprises at least one positive contact for electrically connecting to a positive terminal of a respective at least one battery cell, and each negative lateral projection comprises at least one negative contact for electrically connecting to a negative terminal of a respective at least one other battery cell.

14. The battery module of claim 13, wherein the at least one positive contact comprises a circular portion and the at least one negative contact comprises a semi-annular portion when viewed in a direction orthogonal to a plane of the bus bar.

15. The battery module of claim 13 or 14, wherein at least one positive lateral projection comprises two or more positive contacts for connection to positive terminals of a respective two or more battery cells, and wherein at least one negative lateral projection comprises two or more negative contacts for connection to negative terminals of a respective two or more other battery cells.

16. The battery module of any of claims 13-15, wherein the at least one bus bar has the same number of positive and negative contacts.

17. The battery module of any of claims 13-16, wherein the positive and negative contacts are welded to the respective battery cell terminals to maintain electrical contact.

18. The battery module of claim 17, wherein the positive contact comprises an aperture through which at least a portion of the weld is visible.

19. The battery module of any of the preceding claims, wherein the positive and negative connection portions comprise respective positive and negative bridge portions, each extending over and spaced from an underlying cell terminal.

20. The battery module of any of the preceding claims, wherein the battery module comprises at least two bus bars having the same form.

21. The battery module of any of the preceding claims, wherein the at least one bus bar covers, or the plurality of bus bars together cover, greater than 50%, greater than 60%, or greater than 70% of the surface area of the plurality of battery cells when viewed in a direction orthogonal to the plane of the battery module.

22. A battery pack comprising the battery module of any one of the preceding claims.

23. An electric vehicle comprising the battery module according to any one of claims 1 to 21, or the battery pack according to claim 22.