Battery cell

Abstract

Aspects of the present invention relate to a battery cell (1). The battery cell (1) includes a core (21) having a core central region (23) and a core outer region (25). A plurality of cell electrodes (27A, 27B) are disposed adjacent to the core central region (23). The battery cell (1) includes a casing (31) having a first casing central region (33A) and a first casing outer region (35A). The first casing central region (33A) has a first major surface (34A) and encloses at least some of the cell electrodes (27A). The first casing outer region (35A) at least partially encloses the core outer region (25). The first casing outer region (35A) includes a first clamping surface (41A) disposed on a first side (1A) of the battery cell (1). The first clamping surface (41A) is inset relative to the first major surface (34A) in a first direction towards a central major plane (XY) of the core (21). Aspects of the present invention also relate to a battery module (5) comprising a plurality of the battery cells (1); and a vehicle (3) comprising at least one of the battery cells (5).

Description

[0001] BATTERY CELL

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a battery cell. The battery cell may be used in a vehicle, for example in a traction battery. Aspects of the invention relate to a battery cell, a battery module and a vehicle.

[0004] BACKGROUND

[0005] It is known to provide a vehicle with a battery pack comprising a plurality of battery cells. An important consideration is how to remove or reject the heat from the battery cells. The stiffness of the battery cell should also be sufficient to help prevent damage to the battery cell during use. These thermal and structural considerations will also be relevant to solid-state battery cells. The structure of the battery cell should facilitate electrical connection to associated cells and also enable integration into a larger pack structure. This typically requires a support structure and a separate cooling system to support and cool the battery cells. This may result in inefficient packaging and / or mass.

[0006] One approach is to use a metallic core to give the required strength for the battery cell to operate. The core may be profiled to include a perimeter region having an increased thickness which extends around the electrodes mounted in a central region of the battery cell. This arrangement provides enhanced structural rigidity and may offer protection for the electrodes. The perimeter region of each battery cell typically engages the perimeter region of an adjacent battery cell, thereby determining a spacing between the adjacent battery cells. In this arrangement, only the outer sidewall of the perimeter region is available to establish a thermal connection with the battery cell. However, this may present challenges regarding the extraction of heat from the battery cell into an appropriate cooling interface. Although a cavity may be formed between the central region of the adjacent battery cells, this cavity may be substantially closed by the perimeter region of the battery cell, thereby limiting or restricting the circulation of a cooling fluid.

[0007] It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.

[0008] SUMMARY OF THE INVENTION

[0009] Aspects and embodiments of the invention provide a battery cell, a battery module and a vehicle as claimed in the appended claims. According to an aspect of the present invention there is provided a battery cell comprising: a core comprising a core central region and a core outer region; a plurality of cell electrodes disposed adjacent to the core central region; a casing comprising: a first casing central region enclosing at least some of the cell electrodes, the first casing central region comprising a first major surface; and a first casing outer region at least partially enclosing the core outer region, the first casing outer region comprising a first clamping surface disposed on a first side of the battery cell; wherein the first clamping surface is inset relative to the first major surface in a first direction towards a central major plane of the core.

[0010] The first clamping surface is configured to enable the battery cell to be mounted, for example in a frame. The casing may comprise a second clamping surface, for example provided on a second side of the battery cell. In use, a clamping force may be applied to the first clamping surface and / or the second clamping surface to mount the battery cell. The first clamping surface may form a cooling interface to promote rejection of thermal energy from the battery cell. At least in certain embodiments, the thermal energy is conducted to the core outer region and through the casing into a support structure for the battery cell. In use, the core forms a thermal pathway for conducting thermal energy from within the battery cell into to the support structure. By insetting the first clamping surface relative to the first major surface, access is available between the battery cells when disposed in a pack, a stack or a module. The first and second major surfaces of adjacent battery cells may be spaced apart from each other. This may facilitate mounting of the battery cells. Alternatively, or in addition, this may facilitate heat rejection from the individual battery cells. For example, maintaining a space between adjacent battery cells may facilitate circulation of a cooling fluid between the battery cells in a battery pack to promote heat rejection from the first and second major surfaces of the casing central region. At least in certain embodiments, the battery cell may comprise a volumetrically and gravimetrically efficient structure. The casing outer region may provide a mechanical support for the battery cell and may also provide a thermal cooling pathway. This may provide improved packaging and performance benefits.

[0011] The casing may comprise a second casing outer region at least partially enclosing the core outer region. The second casing outer region may be formed on a second side of the casing. The second casing outer region may comprise a second clamping surface. The second clamping surface may be disposed on a second side of the battery cell. The core outer region may be enclosed by the first casing outer region and / or the second casing outer region. For example, the first and second casing outer regions may extend around an exterior of the core outer region. At least in certain embodiments, the casing comprises first and second clamping surfaces. The first and second clamping surfaces may be disposed on opposite sides of the battery cell. The first and second clamping surfaces may be aligned with each other to facilitate clamping. The first and second clamping surfaces may be offset from each other in a direction perpendicular to the central major plane of the core. The first and second major surfaces of the casing central region are disposed on the first and second sides, respectively. The first and second clamping surfaces are disposed on the first and second sides, respectively.

[0012] The first side of the casing may comprise a first casing central region and a first casing outer (or peripheral) region. The second side of the casing may comprise a second casing central region and a second casing outer (or peripheral) region.

[0013] The casing may comprise a first transition between the first major surface and the first clamping surface. The first transition may comprise or consist of a first sidewall, for example. The first transition may comprise or consist of a first step or a first taper formed between the second major surface and the second clamping surface. The first major surface and the first clamping surface of the casing may be formed integrally. For example, the first major surface and the first clamping surface may be formed from a first sheet member, such as a metal sheet member. The casing may comprise a second casing central region enclosing at least some of the cell electrodes. The second casing central region may be formed on a second side of the casing. The second casing central region may comprise a second major surface.

[0014] The second clamping surface may be inset relative to the second major surface in a direction towards the central major plane of the core. By insetting the second clamping surface relative to the second major surface, access is available between the battery cells when disposed in a pack, a stack or a module. This may facilitate mounting of the battery cells and / or heat rejection from the individual battery cells. The casing may comprise a second transition between the second major surface and the second clamping surface. The second transition may comprise or consist of a second sidewall, for example. The second transition may comprise or consist of a second step or a second taper formed between the second major surface and the second clamping surface. The second major surface and the second clamping surface of the casing may be formed integrally. For example, the second major surface and the second clamping surface may be formed from a second sheet member, such as a metal sheet member.

[0015] The second clamping surface may be inset relative to the second major surface of the second casing central region in a second direction towards the first major surface.

[0016] The first clamping surface may be coincident with at least a portion of the core outer region. Alternatively, or in addition, the second clamping surface may be coincident with at least a portion of the core outer region.

[0017] The first clamping surface may be formed by a portion of the first casing outer region. At least the portion of the first casing outer region which forms the first clamping surface may be disposed in a face-to-face arrangement with a first side of the core outer region. The first casing outer region may engage or contact the first side of the core outer region. The second clamping surface may be formed by a portion of the second casing outer region. At least the portion of the second casing outer region which forms the second clamping surface may be disposed in a face-to-face arrangement with a second side of the core outer region. The second casing outer region may engage or contact the second side of the core outer region.

[0018] At least a portion of each of the first and second clamping surfaces of the casing outer region may be aligned with or coincident with the core outer region.

[0019] At least a portion of an interior of the first clamping surface may contact a first side of the core outer region. At least a portion of an interior of the second clamping surface may contact a second side of the core outer region. This may provide improved thermal contact between the core and the casing to promote heat rejection. This may provide improved mechanical properties, for example to reduce or prevent deformation of the casing. The battery cell may comprise at least one first support member. The core may comprise the at least one first support member. The first support member may extend at least partway around the core central region. The first support member may extend at least partway around a periphery of the core central region. The at least one first support member may comprise a first support surface which is offset from the first clamping surface. The first support surface may be offset from the first clamping surface in a direction away from the central major plane of the core. The at least one first support member may be provided to support the battery cells, for example so that they can be self-supporting to facilitate stacking. The at least one first support member may help to reinforce the battery cell.

[0020] The at least one first support member may be disposed on a first side of the battery cell. The at least one first support member may be disposed in an outer region of the battery cell. The at least one first support member may be disposed coincident with the core outer region. The at least one first support surface may be at least substantially aligned with the first major surface of the first casing central region. The at least one first support surface may be offset from the first major surface of the first casing central region in a direction away from the central major plane of the core.

[0021] The at least one first support member may be mounted to the core. Alternatively, the at least one first support member may be formed integrally with the core. The casing may be formed around the at least one first support member. Alternatively, the at least one first support member may be mounted to an exterior of the casing.

[0022] The battery cell may comprise at least one second support member. The core may comprise the at least one second support member. The second support member may extend at least partway around the core central region. The second support member may extend at least partway around a periphery of the core central region. The at least one second support member may comprise a second support surface which is offset from the second clamping surface. The second support surface may be offset from the second clamping surface in a direction away from the central major plane of the core. The at least one second support member may be provided to support the battery cells, for example so that they can be self- supporting to facilitate stacking. The at least one second support member may help to reinforce the battery cell.

[0023] The at least one second support member may be disposed on a second side of the battery cell. The at least one second support member may be disposed in an outer region of the battery cell. The at least one second support member may be disposed coincident with the core outer region. The at least one second support surface may be at least substantially aligned with the second major surface of the second casing central region. The at least one second support surface may be offset from the second major surface of the second casing central region in a direction away from the central major plane of the core. The at least one second support member may be mounted to the core. Alternatively, the at least one second support member may be formed integrally with the core. The casing may be formed around the at least one second support member. Alternatively, the at least one second support member may be mounted to an exterior of the casing.

[0024] 5

[0025] The at least one first support member may be aligned with the at least one second support member. The at least one first support member and the at least one second support member may be disposed on opposite sides of the battery cell.

[0026] 10 The core central region and the core outer region may have at least substantially the same thickness. The core may comprise a substantially constant thickness. The core may be at least substantially planar. The core may comprise a plate member. The core may be formed of a metal, such as aluminium or steel. Other thermally conductive structural materials may be used to form the core.

[0027] 15

[0028] According to a further aspect of the present invention there is provided a battery module comprising a plurality of the battery cells described herein. The battery module may comprise control / monitoring electronics for controlling the battery cells. The control / monitoring electronics may, for example, control the charging of each battery cell in the battery module.

[0029] >0

[0030] The battery cells may be supported in the battery module in a support structure. The support structure may comprise or consist of a frame. The support structure may be configured to engage the first and second clamping surfaces of each of the battery cells. The frame may be configured to define a spacing between the cores of adjacent pairs of the battery cells.

[0031] >5

[0032] According to an aspect of the present invention there provided a stack comprising a plurality of the battery cells described herein. The stack comprising a plurality of the battery cells. Unlike a battery module, the stack does not include control / monitoring electronics associated with the battery cells.

[0033] 30

[0034] A battery module may comprise adjacent battery cells wherein the at least one first support member and the at least one second support member of the adjacent battery cells have cooperating profiles whereby the first and second profiles interlock with each other to limit or restrict relative movement of the adjacent battery cells in one or more directions.

[0035] 35 According to a further aspect of the present invention there is provided a vehicle comprising one or more of the following: a battery cell as described herein; a battery module as described herein; and a battery stack as described herein. 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

[0036] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0037] Figure 1 shows a sectional view of a battery cell in accordance with an embodiment of the present invention;

[0038] Figure 2 shows the battery cell shown in Figure 1 clamped in a support structure;

[0039] Figure 3A shows the battery cell shown in Figure 2 being introduced into the support structure;

[0040] Figure 3B shows the battery cell being clamped into the support structure;

[0041] Figure 4 shows first and second like battery cells supported in the support structure; Figure 5 shows a sectional view of a battery cell in accordance with a further embodiment of the present invention;

[0042] Figure 6 shows a vehicle for receiving a plurality of the battery cells in accordance with an embodiment of the present invention; and

[0043] Figure 7 shows a battery pack comprising a plurality of the battery cells in accordance with an embodiment of the present invention. DETAILED DESCRIPTION

[0044] A battery cell 1 in accordance with an embodiment of the present invention is described herein with reference to Figures 1 to 4.

[0045] The battery cell 1 is configured to be used in a vehicle 3. As shown schematically in Figure 6, the vehicle 3 in the present embodiment is an automobile. The vehicle 3 in the present embodiment is a battery electric vehicle (BEV). The battery cell 1 may be used in a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHEV). Other applications are contemplated for the battery cell 1.

[0046] The battery cell 1 is described herein with reference to a reference frame XYZ comprising a longitudinal axis X, a transverse axis Y and a vertical axis Z. The orientation of the reference frame XYZ does not necessarily define the orientation of the battery cell 1 within the vehicle 3. It will be understood that the battery cell 1 may have different orientations within the vehicle

[0047] 3. The battery cell 1 has opposite first and second sides 1A, 1 B. The suffixes A and B are used herein to denote features and components disposed on the first and second sides 1A, 1 B respectively of the battery cell 1. The battery cell 1 in the present embodiment is symmetrical about a central major plane XY. In a variant, the battery cell 1 may be asymmetrical about the central major plane XY.

[0048] As described herein, a plurality of the battery cells 1 are arranged to form a battery module 5 (see Figure 7, for example). The battery cells 1 in the battery module 5 have like configurations and are electrically connected to each other. The battery cells 1 may be arranged in a stacked arrangement in the battery module 5. The battery cells 1 are mounted in a support structure 7 to form the battery module 5. As described herein, the support structure 7 is configured to engage an outer region of each of the battery cells 1. The support structure 7 may, for example, be in the form of a frame. Adjacent battery cells 1 are spaced apart from each other in the support structure 7. The cooling of the battery cells 1 may be facilitated by maintaining a space between the adjacent battery cells 1. A cooling fluid, such as air, may be actively circulated in the between the adjacent battery cells 1 , for example by a cooling fan. Furthermore, expansion of each battery cell 1 may be accommodated in the battery module 5. The support structure 7 is configured to support an outer perimeter or region of each of the battery cells 1. As shown schematically in Figure 7, a plurality of the battery modules 5 are arranged to form a battery pack 9. The battery pack 9 may, for example, be a traction battery for supplying electrical power to one or more electric drive units (not shown) provided in the vehicle 3. The battery cells 1 in the battery pack 9 have the same configuration as each other.

[0049] A first one of the battery cells 1 will now be described in more detail.

[0050] The battery cell 1 comprises a cell central region 13 and a cell outer region 15. The cell central region 13 has a first thickness T1 (measured along the vertical axis Z) and the cell outer region 15 has a second thickness T2 (measured along the vertical axis Z). As shown in Figure 1 , the first thickness T1 is greater than the second thickness T2. The battery cell 1 comprises a core 21 having first and second sides 21A, 21 B. The core 21 forms a structural member for supporting the battery cell 1. The core 21 has a rigid structure which resists deformation. The core 21 is formed of a metal, such as steel or aluminium. The core 21 may be formed of other materials which provide appropriate structural and thermal properties. The core 21 may be formed of a composite material or an alloy. In the present embodiment, the core 21 is substantially planar. The core 21 comprises a plate member having a substantially uniform (i.e., constant) thickness. The core 21 comprises a core central region 23 and a core outer region 25. The core outer region 25 extends at least partway around a perimeter of the core central region 23. In the present embodiment, the core outer region 25 extends around the entire periphery of the core central region 23. The core central region 23 and the core outer region 25 have at least substantially the same thickness. The battery cell 1 comprises a plurality of first and second cell electrodes 27A, 27B and an electrolyte. The first and second cell electrodes 27A, 27B are disposed alongside the core central region 23. As shown in Figure 1 , the first and second cell electrodes 27A, 27B are disposed in a face-to-face arrangement on each of the first and second sides 21 A, 21 B of the core 21. A first set of the first cell electrodes 27A is provided on the first side 21 A of the core 21 ; and a second set of the second cell electrodes 27B is provided on the second side 21 B of the core 21. The first and second sets each comprise a plurality of the first and second cell electrodes 27A, 27B. In a variant, the cell electrodes 27A, 27B may be disposed on only one of the first and second sides 21A, 21 B of the core 21. For example, the first cell electrodes 27A or the second cell electrodes 27B may be omitted. The battery cell 1 comprises a casing 31 which forms an exterior of the battery cell 1. The casing 31 has first and second sides 31 A, 31 B disposed on the first and second sides 1A, 1 B of the battery cell 1. The casing 31 forms a housing for the first and second cell electrodes 27A, 27B. In particular, the first and second cell electrodes 27A, 27B are disposed between the core 21 and the casing 31. The casing 31 is composed of one or more sheet members. The one or more sheet members may each comprise a metal sheet member, for example composed of aluminium. The one or more metal sheet members may be press-formed into the desired shape. In the present embodiment, the casing 31 is formed by first and second sheet members which form the first and second sides 31 A, 31 B respectively. The first and second sheet members are joined along their outer edge, for example by a mechanical crimping or folding operation. A seal is formed along the edges of the first and second sheet members to seal the battery cell 1.

[0051] The first side 31 A of the casing 31 comprises a first casing central region 33A and a first casing outer (or peripheral) region 35A. The first casing central region 33A is offset from the first casing outer region 35A (along the vertical axis Z) to form a first chamber 37-1 for receiving the first cell electrodes 27A. The first casing central region 33A and the first casing outer region 35A are formed contiguously. The first casing central region 33A comprises or consists of a first major surface 34A. The first major surface 34A in the present embodiment is substantially planar and extends substantially parallel to the central major plane XY. The first casing central region 33A may have other forms or configurations. The second side 31 B of the casing 31 comprises a second casing central region 33B and a second casing outer (or peripheral) region 35B. The second casing central region 33B is offset from the second casing outer region 35B (along the vertical axis Z) to form a second chamber 37-2 for receiving the second cell electrodes 27B. The second casing central region 33B and the second casing outer region 35B are formed contiguously. The second casing central region 33B comprises or consists of a second major surface 34B. The second major surface 34B in the present embodiment is substantially planar and extends substantially parallel to the central major plane XY. The second casing central region 33B may have other forms or configurations. The first and second major surfaces 34A, 34B are spaced apart from the core 21 (along the vertical axis Z) to form the first and second chambers 37-1 , 37-2. The first and second cell electrodes 27A, 27B and the electrolyte are disposed inside the first and second chambers 37A, 37B. The first and second chambers 37-1 , 37-2 are sealed in the assembled battery cell 1. A peripheral flange 39 is formed around an outer edge of the casing 31 to seal the battery cell 1.

[0052] The first and second casing outer regions 35A, 35B enclose (surround) the core outer region 25. The first and second casing outer regions 35A, 35B are formed around an exterior of the core outer region 25. The first and second casing outer regions 35A, 35B are disposed on opposite sides of the core outer region 25. As shown in Figure 1 , an interior surface of the first and second casing outer regions 35A, 35B contact the first and second sides 21 A, 21 B respectively of the core outer region 25. The exterior of the first and second casing outer regions 35A, 35B form first and second clamping surfaces 41 A, 41 B respectively. In use, the first and second clamping surfaces 41 A, 41 B are clamped by the support structure 7 to fixedly secure the battery cell 1. The first and second clamping surfaces 41 A, 41 B are disposed in a face-to-face arrangement with the respective first and second sides 21 A, 21 B of the core outer region 25. At least one of the first and second clamping surfaces 41 A, 41 B is inset relative to the first and second major surfaces 34A, 34B (along the vertical axis Z) on the corresponding side of the battery cell 1. In the present embodiment, the first and second clamping surfaces 41 A, 41 B are inset (along the vertical axis Z) relative to the respective first and second major surfaces 34A, 34B.

[0053] The first clamping surface 41 A and the first major surface 34A are formed in respective planes extending substantially parallel to and offset from each other (along the vertical axis Z). The first clamping surface 41A is inset relative to the first major surface 34A formed on the first side 31 A of the casing 31. The first clamping surface 41 A is disposed closer to the central major axis XY of the battery cell 1 than the first major surface 34A. A first transition 43A is formed between the first clamping surface 41A and the first major surface 34A. The first transition 43A in the present embodiment comprises a step change in the profile of the first side 31 A of the casing 31. The first transition 43A is formed by a first sidewall disposed between the first clamping surface 41 A and the first major surface 34A, and forms the first transition in the first side 31 A of the casing 31. The first sidewall extends around the perimeter of the first major surface 34A. The first sidewall extends substantially perpendicular to the first clamping surface 41A. In a variant, the first transition may comprise a progressive change in profile, for example comprising a tapered or inclined profile. The first sidewall 43A may be inclined at an angle less than 90° relative to the first clamping surface 41A, for example less than or equal to 60° or 45°. Put another way, the angle of transition between the first sidewall 43A and the first clamping surface 41A may be greater than 90°, for example greater than 120° or greater than 135°. The second clamping surface 41 B and the second major surface 34B are formed in respective planes extending substantially parallel to and offset from each other (along the vertical axis Z). The second clamping surface 41 B is inset relative to the second major surface 34B formed on the second side 31 B of the casing 31. The second clamping surface 41 B is disposed closer to the central major axis XY of the battery cell 1 than the second major surface 34B. A second transition 43B is formed between the second clamping surface 41 B and the second major surface 34B. The second transition 43B in the present embodiment comprises a step change in the profile of the second side 31 B of the casing 31. The first transition 43A is formed by a second sidewall disposed between the second clamping surface 41 B and the second major surface 34B, and forms the second transition in the second side 31 B of the casing 31. The second sidewall extends around the perimeter of the second major surface 34B. The second sidewall extends substantially perpendicular to the second clamping surface 41 B. In a variant, the second transition may comprise a progressive change in profile, for example comprising a tapered or inclined profile. The second sidewall 43B may be inclined at an angle less than 90° relative to the second clamping surface 41 B, for example less than or equal to 60° or 45°. Put another way, the angle of transition between the second sidewall 43B and the second clamping surface 41 B may be greater than 90°, for example greater than 120° or greater than 135°.

[0054] The support structure 7 is configured to apply a clamping force to the first and second clamping surfaces 41 A, 41 B. As shown in Figure 2, the support structure 7 comprises first and second clamping members 51 A, 51 B configured to engage the first and second clamping surfaces 41 A, 41 B respectively. The support structure 7 is composed of a metal, such as aluminium. In a variant, the support structure 7 may be composed of a composite, such as a carbon fibre composite. The support structure 7 comprises one or more mechanical fasteners (not shown) to secure the first and second clamping members 51 A, 51 B and to apply the clamping force. The one or more mechanical fasteners may, for example, comprise a bolt which engages a threaded aperture. As shown in Figures 3A and 3B, the first and second clamping members 51 A, 51 B each comprise a central aperture 53A, 53B. The first and second casing central regions 33A, 33B of each battery cell 1 locate in the central apertures 53A, 53B. One or more battery cells 1 may be fastened to the support structure 7. A plurality of the battery cells 1 may be arranged beside each other in a non-overlapping arrangement. As shown in Figure 4, a plurality of the battery cells 1 may be mounted in the support structure 7 to form the battery module 5. In this arrangement the battery cells 1 are stacked in a column. The support structure 7 in this arrangement comprises a third clamping member 51 C. Adjacent battery cells 1 are spaced apart from each other in the support structure 7 to facilitate cooling and to accommodate expansion of the battery cells 1 .

[0055] The first and second clamping surfaces 41 A, 41 B form cooling interfaces to promote rejection of thermal energy from the battery cell 1 into the support structure 7 (or in the opposite direction if the battery cell is to be warmed). The thermal energy may be conducted from the core central region 23 to the core outer region 25. A thermal contact is established between the first and second clamping surfaces 41 A, 41 B and the first and second clamping members 51 A, 51 B. In use, the core 21 forms a thermal pathway for conducting thermal energy from within the battery cell 1 into the support structure 7 (or vice versa). It will be appreciated that the core 21 may be extended within the central major plane XY to increase the size of the first and second clamping surfaces 41 A, 41 B, thereby increasing the available cooling surfaces. Unlike prior art arrangements, this modification may be made without changing the spacing between adjacent battery cells 1 (in the vertical axis Z). The support structure 7 could be used to facilitate transportation and / or handling of one or more of the battery cells 1. For example, the battery cells 1 may be mounted in the support structure 7 after assembly. The support structure 7 may be transported along with the one or more battery cells 1 , for example to transport the battery cells 1 to an assembly station for assembly into a battery pack of the type described herein. The support structure 7 could be moulded from a polymer, for example. It will be understood that the support structure 7 may be re-used. The support structure 7 may comprise a releasable clamping member. The clamping member may be movably mounted to one of the first and second clamping members 51 A, 51 B and operable to engage the other one of the first and second clamping members 51A, 51 B.

[0056] The battery cell 1 in the above embodiment comprises a core 21 have a substantially constant thickness. A further embodiment of the battery cell 1 will now be described with reference to Figure 5. Like reference numerals are used for like components. The core 21 of the battery cell 1 is modified in the present embodiment. In particular, the core outer region 25 is modified to incorporate at least one support member 61 A, 61 B for supporting the battery cell 1. The at least one support member 61 may be formed integrally with the core 21 or may be formed as a separate component which is fastened to the core 21. The at least one support member 61 helps to protect the first and second cell electrodes 27A, 27B from damage. The description herein focuses on the changes to the core 21 in the present embodiment to incorporate the at least one support member 61.

[0057] As shown in Figure 5, the core 21 comprises a first support member 61 A disposed on the first side 21A of the core 21 . The first support member 61A is located in the core outer region 25. The first support member 61 A is inset from the edge of the edge of the core 21 proximal to the core central region 23. The first clamping surface 41A is formed outboard of (i.e., externally of) the first support member 61A. The first support member 61A projects upwardly from the core 21 beyond the height of the first casing central region 33A. The first support member 61 A extends around a periphery of the core central region 23 to form a protective sidewall. The first support member 61A in the present embodiment extends continuously or substantially continuously around the cell central region 13. In a variant, a plurality of the first support members 61A may be provided to form a discontinuous or interrupted wall around the cell central region 13. Alternatively, or in addition, one or more apertures may be formed in the first support member 61 A. The first support member 61 A may, for example, be castellated.

[0058] The first support member 61 A may be configured to support another like battery cell 1. For example, when two or more of the battery cells 1 are arranged on top of each other, or side- by side, the first support member 61 A provides support for the adjacent battery cell 1. The first support member 61A comprises at least one first support surface 63A. The at least one first support surface 63A is formed on an outer surface of the first support member 61A. The at least one first support surface 63A is spaced apart from the first clamping surface 41A. The at least one first support surface 63A may be substantially aligned with the first major surface 34A of the first casing central region 33A. In the present embodiment, the at least one first support surface 63A is offset from the first major surface 34A of the first casing central region 33A in a direction away from the central major plane of the core 21. As shown in Figure 5, the core 21 comprises a second support member 61 B disposed on the second side 21 B of the core 21 . The second support member 61 B is located in the core outer region 25. The second support member 61 B is inset from the edge of the edge of the core 21 proximal to the core central region 23. The second clamping surface 41 B is formed outboard of (i.e., externally of) the second support member 61 B. The second support member 61 B projects upwardly from the core 21 beyond the height of the second casing central region 33B.

[0059] The second support member 61 B extends around a periphery of the cell central region 13 to form a protective sidewall. The second support member 61 B in the present embodiment extends continuously or substantially continuously around the cell central region 13. In a variant, a plurality of the second support members 61 B may be provided to form a discontinuous or interrupted wall around the cell central region 13. Alternatively, or in addition, one or more apertures may be formed in the second support member 61 B. The second support member 61 B may, for example, be castellated.

[0060] The second support member 61 B may be configured to support another like battery cell 1. For example, when two or more of the battery cells 1 are arranged on top of each other, or side- by side, the second support member 61 B provides support for the adjacent battery cell 1. The second support member 61 B comprises at least one second support surface 63B. The at least one second support surface 63B is formed on an outer surface of the second support member 61 B. The at least one second support surface 63B is spaced apart from the second clamping surface 41 B. The at least one second support surface 63B may be substantially aligned with the second major surface 34B of the second casing central region 33B. In the present embodiment, the at least one second support surface 63B is offset from the second major surface 34B of the second casing central region 33B in a direction away from the central major plane of the core 21.

[0061] The casing 31 encloses the first and second support members 61 A, 61 B. The first side 31 A of the casing 31 conforms to the shape of the first support member 61A. The first sidewall 43A conforms to an outer surface of the first support member 61 A and transitions to the first clamping surface 41 A. The second side 31 B of the casing 31 conforms to the shape of the second support member 61 B. The second sidewall 43B conforms to an outer surface of the second support member 61 B and transitions to the second clamping surface 41 B.

[0062] The first clamping surface 41 A and the first major surface 34A are formed in respective planes extending substantially parallel to and offset from each other (along the vertical axis Z). The first clamping surface 41A is inset relative to the first major surface 34A formed on the first side 31 A of the casing 31. The first clamping surface 41 A is disposed closer to the central major axis XY of the battery cell 1 than the first major surface 34A. The second clamping surface 41 B and the second major surface 34B are formed in respective planes extending substantially parallel to and offset from each other (along the vertical axis Z). The second clamping surface 41 B is inset relative to the second major surface 34B formed on the second side 31 B of the casing 31. The second clamping surface 41 B is disposed closer to the central major axis XY of the battery cell 1 than the second major surface 34B.

[0063] A plurality of the battery cells 1 are supported in the support structure 7 to form the battery module 5. The support structure 7 applies a clamping force to the first and second clamping surfaces 41 A, 41 B of each of the battery cells 1 . The first and second clamping members 51 A, 51 B are configured to engage the first and second clamping surfaces 41 A, 41 B respectively.

[0064] The first and second support members 61 A, 61 B of adjacent battery cells 1 cooperate with each other. The height (measured along the vertical axis Z) of the first and second support members 61 A, 61 B determines the spacing between adjacent battery cells 1 in the battery module. The first and second support members 61 A, 61 B may have the same or different heights. The first support member 61A preferably extends above the height of the first major surface 34A. The second support member 61 B preferably extends above the height of the second major surface 34B. In a variant one of the first and second support members 61 A, 61 B may be omitted. The first and second support members 61 A, 61 B may have cooperating profiles. For example, the first and second support members 61 A, 61 B may have interlocking profiles. The first support member 61 A may comprise a first profile; and the second support member 61 B may comprise a second profile. The first and second profiles may interlock with each other. The first and second profiles may interlock with each other to limit or restrict relative movement in one or more directions, for example to restrict movement in a plane extending parallel to the central major axis XY. Alternatively, or in addition, the first and second profiles may cooperate with each other to align adjacent battery cells 1 . 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. The at least one support member 61 has been described as being formed in the core 21 of the battery cell 1. In a variant, the at least one support member 61 may be disposed on an exterior of the battery cell

[0065] 1 , for example mounted to an exterior of the casing 31 . A mechanical fastener or an adhesive fastener may be used to fasten the at least one support member 61 to the casing 31 .

Claims

CLAIMS1. A battery cell comprising: a core comprising a core central region and a core outer region; a plurality of cell electrodes disposed adjacent to the core central region; a casing comprising: a first casing central region enclosing at least some of the cell electrodes, the first casing central region comprising a first major surface; and a first casing outer region at least partially enclosing the core outer region, the first casing outer region comprising a first clamping surface disposed on a first side of the battery cell; wherein the first clamping surface is inset relative to the first major surface in a first direction towards a central major plane of the core.

2. A battery cell as claimed in claim 1 , wherein the casing comprises a second casing outer region at least partially enclosing the core outer region, the second casing outer region comprising a second clamping surface disposed on a second side of the battery cell.

3. A battery cell as claimed in any one of claims 1 or 2, wherein the casing comprises a second casing central region enclosing at least some of the cell electrodes, the second casing central region comprising a second major surface.

4. A battery cell as claimed in claims 2 and 3, wherein the second clamping surface is inset relative to the second major surface in a direction towards the central major plane of the core.

5. A battery cell as claimed in any one of the preceding claims, wherein at least a portion of the first clamping surface of the first casing outer region is disposed in a face-to-face arrangement with the core outer region.

6. A battery cell as claimed in any one of the preceding claims, wherein the core comprises at least one first support member disposed coincident with the core outer region, the at least one first support member having a first support surface which is offset from the first clamping surface in a direction away from the central major plane of the core.

7. A battery cell as claimed in claim 6, wherein the at least one first support surface is offset from the first major surface of the first casing central region in a direction away from the central major plane of the core.

8. A battery cell as claimed in any one of the preceding claims, wherein the core comprises at least one second support member disposed coincident with the core outer region, the at least one second support member having a second support surface which is offset from the second clamping surface in a direction away from the central major plane of the core.

9. A battery cell as claimed in claim 8 when dependent directly or indirectly on claim 3, wherein the at least one second support surface is offset from the second major surface of the second casing central region in a direction away from the central major plane of the core.

10. A battery cell as claimed in any one of claims 6 to 9, wherein the at least one first support member and / or the at least one second support member are formed integrally with the core, the casing being formed around the at least one first support member and / or the at least one second support member.

11. A battery cell as claimed in any one of the preceding claims, wherein the core central region and the core outer region have at least substantially the same thickness, and / or wherein the core is at least substantially planar.

12. A battery module comprising a plurality of the battery cells as claimed in any one of the preceding claims, wherein the battery cells are supported in a support structure configured to engage the first and second clamping surfaces of each of the battery cells.

13. A battery module as claimed in claim 12, wherein the support structure is configured to define a spacing between the cores of adjacent pairs of the battery cells.

14. A battery module as claimed in claim 12 or 13 when dependent on claims 8, 9 or 10, wherein the at least one first support member and the at least one second support member of adjacent battery cells in the module have cooperating profiles whereby the first and second profiles interlock with each other to limit or restrict relative movement of the adjacent battery cells in one or more directions.

15. A vehicle comprising at least one battery cell as claimed in any one of claims 1 to 11 or a battery module as claimed in any one of claims 12 to 14.

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