Battery cell

Abstract

Aspects of the present invention relate to a battery cell (10). The battery cell (10) includes a first electrode stack (12); a second electrode stack (14); and a terminal structure (16). The terminal structure (16) is sandwiched between and connected to each of the first electrode stack (12) and the second electrode stack (14). The terminal structure (16) comprises: a first terminal (18); a second terminal (20); and an electrical insulator (22). The electrical insulator (22) is sandwiched between and connected to each of the first terminal (18) and the second terminal (20). A portion of the terminal structure (16) forms an outer wall (112) of the battery cell (10). The outer wall (112) surrounds an outer periphery of each of the first electrode stack (12) and the second electrode stack (14).

Description

[0001] BATTERY CELL

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a battery cell. Aspects of the invention relate to a battery cell, to a battery cell stack, and to a vehicle.

[0004] BACKGROUND

[0005] It is known to provide battery cells, for example pouch and prismatic battery cells, having internal electrodes that are terminated together within the cell and then presented to the outside of the cell in the form of dedicated terminal pads or tabs. The terminal pads or tabs of battery cells are connected together in series or parallel to form a battery. The incremental connections take up valuable volume that could be used for energy storage and can result in losses that impact the performance and reliability of the battery. Such batteries are not suitable for high current applications, for example automotive applications.

[0006] It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.

[0007] SUMMARY OF THE INVENTION

[0008] Aspects and embodiments of the invention provide a battery cell, a battery cell stack, and a vehicle as claimed in the appended claims

[0009] According to an aspect of the present invention there is provided a battery cell comprising a first electrode stack, a second electrode stack and a terminal structure sandwiched between and connected to each of the first electrode stack and the second electrode stack.

[0010] The terminal structure may include a first terminal, a second terminal and an electrical insulator sandwiched between and connected to each of the first terminal and the second terminal.

[0011] A portion of the terminal structure may form an outer wall of the battery cell. The outer wall may, for example, surround an outer periphery of the first electrode stack and / or an outer periphery of the second electrode stack.

[0012] The sandwich structure advantageously enables more efficient packing of the battery cell volume, which is particularly beneficial for high current applications such as automotive applications.

[0013] According to another aspect of the present invention there is provided a battery cell comprising: a first electrode stack; a second electrode stack; and a terminal structure sandwiched between and connected to each of the first electrode stack and the second electrode stack; wherein the terminal structure comprises: a first terminal; a second terminal; and an electrical insulator sandwiched between and connected to each of the first terminal and the second terminal; and wherein a portion of the terminal structure forms an outer wall of the battery cell, which outer wall surrounds an outer periphery of each of the first electrode stack and the second electrode stack.

[0014] Advantageously, the terminal structure provides enhanced structural rigidity and / or integrity to the battery cell. The sandwich structure also enables more efficient packing of the battery cell volume.

[0015] Optionally, the first terminal is one of a positive terminal or a negative terminal; and the second terminal is the other of a positive terminal or a negative terminal. In an embodiment, the first terminal comprises a first terminal planar body and a first terminal outer frame extending around an outer periphery of the first terminal planar body and wherein one of the first electrode stack and the second electrode stack contacts the first terminal planar body within the first terminal outer frame. The second terminal may comprise a second terminal planar body and a second terminal outer frame extending around an outer periphery of the second terminal planar body. The other of the first electrode stack and the second electrode stack may contacts the second terminal planar body within the second terminal outer frame.

[0016] The larger surface area of connection between the terminal planar body and the respective electrode stack advantageously provides improved connectivity between the components and hence improves the electrical and thermal properties of the battery cell. The terminal outer frame provides a protective boundary around an outer edge of the respective electrode stack, further improving the structural integrity of the battery cell.

[0017] The first terminal outer frame may comprise one of a tab and a recess. The second terminal outer frame may comprises the other of the tab and the recess. The recess may be configured to receive a tab of an adjacent battery cell. Advantageously, the tab and the recess provide a structural connection between adjacent battery cells.

[0018] The first terminal outer frame may comprise one of a plurality of tabs or a plurality of recesses. The second terminal outer frame may comprise the other of the plurality of tabs and the plurality of recesses. The plurality of the tabs and the recesses provide a greater surface area for connection and offers the advantage of a stronger connection between adjacent battery cells. The plurality of tabs and the plurality of recesses may be distributed around a periphery of the respective outer frames. Advantageously, this results in a greater surface area for connection and so a stronger connection between adjacent battery cells.

[0019] The or each tab and the or each recess may form terminal connector portions for the respective terminals. Beneficially, the tabs and recesses provide a greater surface area for connection and so a stronger electrical connection between adjacent battery cells. By forming terminal connector portions, the tabs and recesses remove the need to provide separate connectors, e.g. busbars.

[0020] In an embodiment, the portion of the terminal structure which forms the outer wall of the battery cell comprises a portion of the first terminal and a portion of the second terminal such that the outer wall of the battery cell comprises an integrated first terminal connector portion and an integrated second terminal connector portion. This is advantageous as the larger and more integral terminal structures remove need for separate connectors (e.g. busbars).

[0021] The first terminal connector portion may be the same polarity as the first terminal. The second terminal connector portion may be the same polarity as the second terminal.

[0022] In an embodiment, the electrical insulator of the terminal structure comprises an electrical insulator planar body and an electrical insulator outer frame extending around an outer periphery of the electrical insulator planar body. One of the first terminal and the second terminal contacts the electrical insulator planar body within the electrical insulator outer frame.

[0023] The first terminal may contact a first face of the electrical insulator. The second terminal may contact a second opposing face of the electrical insulator. The arrangement of the electrical insulator further improves the efficiency with which the battery cell components can be packed. In an embodiment, the electrical insulator planar body comprises an opening and the first terminal planar body comprises a first terminal opening. A first electrode connector portion of one of the first electrode stack and the second electrode stack is connected to the first terminal. A second electrode connector portion of the one of the first electrode stack and the second electrode stack extends through the opening in the electrical insulator planar body and the first terminal opening and is connected to the second terminal. In this way, the electrical performance of the battery cell is improved.

[0024] The opening in the electrical insulator planar body may be a first opening. The electrical insulator planar body may comprise a second opening and the second terminal planar body may comprise a second terminal opening. A first electrode connector portion of the other of the first electrode stack and the second electrode stack may be connected to the second terminal. A second electrode connector portion of the other of the first electrode stack and the second electrode stack may extend through the second opening in the electrical insulator planar body and the second terminal opening and may be connected to the first terminal. The electrical performance of the battery cell may therefore be improved.

[0025] Each electrode stack may comprise interleaved negative polarity generating plates and positive polarity generating plates, each of the negative polarity generating plates being connected together at one end of the electrode stack to form said first or second electrode connector portion and each of the positive polarity generating plates being connected together at another end of the electrode stack to form the other of said first or second electrode connector portion, and the openings in the electrical insulator planar body and the respective one of the first and second terminal openings are aligned with the respective first and second electrode connector portions at the ends of each electrode stack.

[0026] The first electrode stack, the second electrode stack and the terminal structure may be sandwiched between a first cover layer and a second cover layer. The first and second cover layers advantageously provide structural integrity to the cell and provide rigidity to the battery cell structure.

[0027] According to another aspect of the invention there is provided a battery cell stack comprising one or more battery cells according to the preceding aspect of the invention.

[0028] According to a further aspect of the invention there is provided a vehicle comprising one or more battery cells or a battery cell stack according to the preceding aspects of the invention.

[0029] According to a further aspect of the invention there is provided a battery cell comprising first and second electrode stacks, each having a negative electrical polarity end at which negative electrical charge generating plates of the stack have a negative electrode connector portion and an opposite positive electrical polarity end at which positive electrical charge generating plates of the stack have a positive electrode connector portion. The positive and negative planar terminals having sides disposed against opposite sides of a planar electrical insulator that mounts and electrically isolates the positive and negative planar terminals from each other. The first and second electrode stacks being mounted on sides of the positive and negative planar terminals respectively, which sides are remote from the planar electrical insulator. The positive electrode connector portion of the first electrode stack is directly connected to the positive terminal and the negative electrode connector portion of the first electrode stack passes through an aperture in the positive terminal, through a first aperture in the planar electrical insulator and is connected to the negative terminal. The negative electrode connector portion of the second electrode stack is directly connected to the negative terminal and the positive electrode connector portion of the second electrode stack passes through an aperture in the negative terminal, through a second aperture in the planar electrical insulator and is connected to the positive terminal.

[0030] The negative electrode connector portion of the first electrode stack may be connected to side of the negative terminal that is disposed against the planar electrical insulator and the positive electrode connector portion of the second electrode stack may be connected to side of the positive terminal that is disposed against the planar electrical insulator.

[0031] The first and second electrode stacks may comprise substantially rectangular electrical charge generating plates and the positive and negative terminals and the planar electrical insulator may be correspondingly substantially rectangular with longer side lengths than the side lengths of the electrical charge generating plates.

[0032] Portions of the positive and negative terminals and the planar electrical insulator may extend beyond the first and second electrode stacks to form an outer wall of the battery cell, which outer wall may surround an outer periphery of each of the first and second electrode stacks.

[0033] The outer wall of one of the positive and negative terminals may have tabs extending substantially perpendicularly away from the planar electrical insulator and the outer wall of the other of the positive and negative terminals may have recesses extending substantially perpendicularly with respect to the plane of the terminal, the tabs may be extending in said perpendicular direction beyond a thickness of the electrode stack.

[0034] The tabs and recesses may be distributed around the outer wall such that a tab on one of the positive and negative terminals engages with and electrically connects to a recess on the other of the positive and negative terminals when two battery cells are mated together to form a battery pack.

[0035] The outer wall may extend in a direction substantially perpendicular to the planes of the electrode stacks, terminals and insulator, and wherein at least one of the recesses may be a recess in an outer wall forming part of the positive or negative terminal, which recess may extend in said perpendicular direction towards a rear edge of the recess and in a direction parallel to said planes towards a floor of the recess, whereby a tab of an adjoining cell engages and connects with at least the floor of the recess.

[0036] One of the positive and negative terminals may have two tabs, one on each of opposite sides of the cell, and the other of the positive and negative terminals may have corresponding recesses, whereby two cells joined together with each of said tabs engaging each of said recesses are constrained by the tabs and recesses against movement in a direction parallel the planes of the electrode stacks, terminals and insulator and parallel a line between said opposing tabs.

[0037] Opposing tabs and recesses may be disposed around the outer wall whereby two cells joined together with each of said tabs engaging each of said recesses are constrained by the tabs and recesses against movement in any direction parallel the planes of the electrode stacks, terminals and insulator.

[0038] Each of the positive and negative electrical charge generating plates of the first and second stacks may extend at either end of each stack beyond the ends of the other of the positive and negative electrical charge generating plates, whereby the extended portions of the respective electrical charge generating plates may be joined together to form said electrode connector portions. Each electrode connector portion may be as wide as the width of the ends of the stack from which the electrical charge generating plates extend and the apertures in the terminals and insulator through which a respective electrode connector portion passes may be elongate to accommodate said width, connection of the electrode connector portions to the respective terminal being along a line as long as the width of the stacks.

[0039] 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.

[0040] BRIEF DESCRIPTION OF THE DRAWINGS

[0041] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0042] Figure 1 shows a schematic view of a battery cell;

[0043] Figure 2 shows an exploded view of the battery cell of Figure 1 ;

[0044] Figure 3 shows a schematic view of an electrode stack of the battery cell of Figure 1 ;

[0045] Figure 4 shows an enlarged portion of the exploded view of Figure 2;

[0046] Figure 5 shows an alternative enlarged portion of the exploded view of Figure 2;

[0047] Figure 6 shows another enlarged portion of the exploded view of Figure 2;

[0048] Figure 7 shows a partial cross section view through line A-A of the battery cell of Figure 1;

[0049] Figure 8 shows an alternative partial cross section view through line A-A of the battery cell of Figure 1;

[0050] Figure 9 shows a schematic view of a battery cell stack;

[0051] Figure 10 shows a partial exploded view of the battery cell stack of Figure 9;

[0052] Figure 11 shows an alternative schematic view of the battery cell stack of Figure 9; and

[0053] Figure 12 shows a vehicle.

[0054] DETAILED DESCRIPTION

[0055] A battery cell 10 in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figures 1 to 8. As shown in Figures 9 to 11, the battery cell 10 is included within a battery cell stack 200 which comprises a plurality of battery cells 10. As shown in Figure 12, the battery cell 10, for example as part of a battery cell stack 200, is installed in a vehicle 300.

[0056] With reference to Figures 1 to 8, the battery cell 10 has a layered or sandwich-like structure. The battery cell 10 has a first electrode stack 12, a second electrode stack 14 and a terminal structure 16. The terminal structure 16 is positioned intermediate, or sandwiched between, and connected to each of the first electrode stack 12 and the second electrode stack 14. With particular reference to Figure 2, it can be seen that the terminal structure 16 includes a first terminal 18, a second terminal 20 and an electrical insulator or core 22. The electrical insulator 22 is positioned intermediate, or sandwiched between, and connected to each of the first terminal 18 and the second terminal 20.

[0057] As will be described in more detail below, a portion of the terminal structure 16 forms an outer wall 112 of the battery cell 10. The outer wall 112 surrounds an outer periphery of each of the first electrode stack 12 and the second electrode stack 14.

[0058] The battery cell 10 also includes a first cover layer 24 and a second cover layer 26. The first electrode stack 12, the second electrode stack 14 and the terminal structure 16 are positioned intermediate, or sandwiched between, the first cover layer 24 and the second cover layer 26.

[0059] Referring now to Figure 3, the first electrode stack 12 is a generally planar structure that is generally rectangular in plan view and includes a stack of layers of active material 400, for example layers of lithium-containing active materials each separated by a polymeric or ceramic separator, which are sandwiched between a first electrode layer 402 (for example an anode layer including copper or lithium) and a second electrode layer 404 (for example a cathode layer including aluminium). The first electrode stack 12 has a first face 29 and a second, opposing, face 30. A first electrode connector portion 32, which is formed by a plurality of the second electrode layers 404 being electrically and mechanically joined together, extends from a first end of the first electrode stack 12 and a second electrode connector portion 36, which is formed by a plurality of the first electrode layers 402 being electrically and mechanically joined together, extends from a second, opposing, end of the first electrode stack 12. The first electrode connector portion 32 has a first electrical polarity and the second electrode connector portion 36 has a second electrical polarity.

[0060] The second electrode stack 14 is structurally the same as the first electrode stack 12 and so is also described with reference to Figure 3. The second electrode stack 14 is a generally planar structure that is generally rectangular in plan view and includes a stack of layers of active material 400, for example layers of lithium-containing active materials each separated by a polymeric or ceramic separator, which are sandwiched between a first electrode layer 402 (for example an anode layer including copper or lithium) and a second electrode layer 404 (for example a cathode layer including aluminium). The second electrode stack 14 has a first face 41 and a second, opposing, face 42. A first electrode connector portion 44, which is formed by a plurality of the second electrode layers 404 being electrically and mechanically joined together, extends from a first end of the second electrode stack 14 and a second electrode connector portion 48, which is formed by a plurality of the first electrode layers 402 being electrically and mechanically joined together, extends from a second, opposing, end of the second electrode stack 14. The first electrode connector portion 44 has the first electrical polarity and the second electrode connector portion 48 has the second electrical polarity.

[0061] The first polarity of the first electrode connector portion 32 of the first electrode stack 12 is the same as the first polarity of the first electrode connector portion 44 of the second electrode stack 14. Similarly, the second polarity of the second electrode connector portion 36 of the first electrode stack 12 is the same as the second polarity of the second electrode connector portion 48 of the second electrode stack 14.

[0062] With particular reference to Figure 4, the first terminal 18 is a metallic structure including aluminium or a similarly conductive metal or metal alloy which, for example, may be press-formed (pressed) or die-cast (cast). In embodiments where the metallic structure is manufactured by casting, the metallic structure comprises an upstanding surrounding lip. In embodiments where the metallic structure is manufactured by pressing, the upstanding surrounding lip is not required. The first terminal 18 has a planar body 54 (the first terminal planar body) having a first face 51 (not visible in Figure 4) and a second, opposing, face 52. The first terminal 18 also has an outer rim or frame 56 which extends around the periphery of the planar body 54 (the first terminal outer frame). The outer frame 56 includes a castellated portion 58 having a first, castellated, edge 60 from which one or more tabs 62 extend away from the second face 52 of the planar body 54. The tabs 62 are separated by castel lations or gaps 63. The castellated portion 58 has a second, smooth, edge 64. The outer frame 56 defines a hollow or cavity (not visible in Figure 4) on the first face 51 of the first terminal 18. The first terminal 18 includes an aperture or opening 65 at one end of the planar body 54 (as shown in Figures 4 and 7). The opening 65 extends through the first face 51 and the second face 52 of the planar body 54. The first terminal 18 includes a hole 57 which is located in and extends through the outer frame 56.

[0063] In this embodiment, the planar body 54 of the first terminal 18 is generally rectangular in plan view. In other embodiments, the planar body 54 may be any shape in plan view, for example the planar body may be circular, triangular, quadrilateral or any two dimensional polygon shape in plan view.

[0064] The castellated portion 58 of the outer frame 56 of the first terminal 18 extends around the outer periphery of the planar body 54, e.g. the castellated portion 58 extends along each of the four edges or sides of the generally rectangular outer frame 56 which extends around the outer periphery of the planar body 54 of the first terminal 18. In embodiments of the invention, the castellated portion 58 may extend along any number of the edges or sides of the outer frame 56. The castellated portion 58 may, for example, extend along one, some or all of the edges or sides of the outer frame 56. In embodiments, the castellated portion 58 may extend along one, two, three, four, or more edges or sides of the outer frame 56.

[0065] As shown in Figure 4, three tabs 62, separated by two gaps 63, are provided on the castellated portion 58 of the outer frame 56 which extends along a long edge or side of the planar body 54 of the first terminal 18. A corresponding arrangement of tabs 62 and gaps 63 may be provided on the opposing long side or edge of the planar body 54 of the first terminal 18. As also shown in Figure 4, one tab 62 is provided on the castellated portion 58 of the outer frame 56 which extends along a short edge or side of the planar body 54. A corresponding arrangement of tabs 62 may be provided on the opposing short side or edge of the planar body 54 of the first terminal 18. The tabs 62 may thus be distributed around a periphery, for example an outer periphery, of the outer frame 56 of the first terminal 18.

[0066] In embodiments, any number of tabs 62 may be provided on the castellated portion 58 of the outer frame 56 of the first terminal 18. In embodiments, the size, for example, the surface area or the length, of each of the tabs 62 may be increased or decreased, e.g. according to the number of tabs 62 that are provided on the castellated portion 58 of the outer frame 56, the size and / or the shape of the first terminal 18 and / or one or more other requirements of the battery cell 10.

[0067] As shown in Figures 2 and 4, each of the tabs 62 is generally trapezoid in plan view. In embodiments, the tabs 62 of the first terminal 18 may be any shape in plan view, for example the tabs may be circular, triangular, quadrilateral or any two dimensional polygon shape in plan view.

[0068] Similarly, and with particular reference to Figures 5 and 6, the second terminal 20 is a metallic structure including aluminium or a similarly conductive metal or metal alloy which, for example, may be press-formed or die-cast. The second terminal 20 has a planar body 68 (the second terminal planar body) having a first face 67 (not visible in Figures 5 and 6) and a second, opposing, face 66. The second terminal 20 also has an outer rim or frame 70 which extends around the periphery of the planar body 68 (the second terminal outer frame). The outer frame 70 includes a number of recesses 72. The recesses 72 are separated by tab-shaped wall portions 73. The outer frame 70 defines a hollow or cavity 74 on the second face 66 of the second terminal 20. The second terminal 20 includes an aperture or opening 75 at one end of the planar body 68 (as also shown in Figure 8). The opening 75 extends through the first face 67 and the second face 66 of the planar body 68. The second terminal 20 includes a hole 71 which is located in and extends through the outer frame 70.

[0069] In this embodiment, the planar body 68 of the second terminal 20 is generally rectangular in plan view. In other embodiments, the planar body 68 may be any shape in plan view, for example the planar body may be circular, triangular, quadrilateral or any two dimensional polygon shape in plan view. To facilitate efficient packing of the battery cell volume, the shape of the planar body 68 of the second terminal 20 corresponds to the shape of the planar body 54 of the first terminal 18.

[0070] The outer frame 70 extends around the outer periphery of the planar body 68 of the second terminal 20, e.g. the outer frame 70 extends along each of the four edges or sides of the outer periphery of the planar body 68. In embodiments of the invention, the outer frame 70 may extend along any number of the edges or sides of the outer periphery of the planar body 68. The outer frame 70 may, for example, extend along one, some or all of the edges or sides of the outer periphery of the planar body 68. In embodiments, the outer frame 70 may extend along one, two, three, four or more edges or sides of the outer periphery of the planar body 68.

[0071] As shown in Figure 5, three recesses 72, separated by two tab-shaped wall portions 73, are provided on the outer frame 70 which extends along a long edge or side of the outer periphery of the planar body 68 of the second terminal 20. A corresponding arrangement of recesses 72 and tab-shaped wall portions 73 may be provided on the opposing long side or edge of the planar body 68 of the second terminal 20. As also shown in Figure 5, one recess 72 is provided on the outer frame 70 which extends along a short edge or side of the outer periphery of the planar body 68. A corresponding arrangement of recesses 72 may be provided on the opposing short side or edge of the planar body 68 of the second terminal 20. The recesses 72 may thus be distributed around a periphery, for example an outer periphery, of the outer frame 70 of the second terminal 20. In embodiments, any number of recesses 72 may be provided on the outer frame 70 of the second terminal 20. The number of recesses 72 provided on the second terminal 20 corresponds to the number of tabs 62 provided on the first terminal 18.

[0072] In embodiments, the size, for example, the surface area or length, of each of the recesses 72 may be increased or decreased, e.g. according to the number of recesses 72 that are provided on the outer frame 70, the size and / or the shape of the second terminal 20 and / or one or more other requirements of the battery cell 10. The size, for example the surface area or length, of recesses 72 provided on the second terminal 20 corresponds to the size, for example the surface area or length, of tabs 62 provided on the first terminal 18.

[0073] As shown in Figures 2 and 5, each of the recesses 72 is generally trapezoid in plan view. In embodiments, the recesses may be any shape in plan view, for example the recesses may be circular, triangular, quadrilateral or any two dimensional polygon shape in plan view. The shape of recesses 72 provided on the second terminal 20 corresponds to the shape of tabs 62 provided on the first terminal 18.

[0074] Referring now to Figure 6, the electrical insulator or core 22 is made from a non-conductive material, for example a polymeric or plastic material such as polyamide 6 (also known as PA6 or nylon 6) or a non-conductive ceramic material. The electrical insulator 22 has a generally planar body 76 (the electrical insulator planar body) and an outer rim or frame 78 which extends around the periphery of the planar body 76 (the electrical insulator outer frame). The outer frame 78 defines a first hollow or cavity (not shown) on a first face 81 (not visible in Figure 6) of the electrical insulator 22 and a second hollow or cavity 80 on a second, opposing, face 82 of the electrical insulator 22. The outer frame 78 has a first, smooth, edge 84 which extends away from the first face of the electrical insulator 22 and a second, castellated, edge 86 which extends away from the second face 82 of the electrical insulator 22. The second, castellated, edge 86 includes a plurality of tabs 88 which are separated by castellations or gaps 89. A first aperture or opening 94 is provided at a first end of the planar body 76 of the electrical insulator 22 and a second aperture or opening 90 is provided at a second end of the planar body 76 of the electrical insulator 22.

[0075] In this embodiment, the planar body 76 of the electrical insulator 22 is generally rectangular in plan view. In other embodiments, the planar body 76 may be any shape in plan view, for example the planar body may be circular, triangular, quadrilateral or any two dimensional polygon shape in plan view. To facilitate efficient packing of the battery cell volume, the shape of the planar body 76 of the electrical insulator 22 corresponds to the shape of each of the planar body 68 of the second terminal 20 and the planar body 54 of the first terminal 18.

[0076] The outer frame 78 extends around the outer periphery of the planar body 76, e.g. the outer frame 78 extends along each of the four edges or sides of the outer periphery of the planar body 76. In embodiments of the invention, the outer frame 78 may extend along any number of the edges or sides of the outer periphery of the planar body 76. The outer frame 78 may, for example, extend along one, some or all of the edges or sides of the outer periphery of the planar body 76. In embodiments, the outer frame 78 may extend along one, two, three, four or more edges or sides of the outer periphery of the planar body 76.

[0077] As shown in Figure 6, two tabs 88, separated by three gaps 89, are provided on the outer frame 78 which extends along a long edge or side of the outer periphery of the planar body 76 of the electrical insulator 22. A corresponding arrangement of tabs 88 and gaps 89 may be provided on the opposing long edge or side of the outer frame 78 of the planar body 76 of the electrical insulator 22. As also shown in Figure 6, one gap 89 is provided on the outer frame 78 which extends along a short edge or side of the outer periphery of the planar body 68. A corresponding arrangement of gaps 89 may be provided on the opposing short edge or side of the outer frame 78 of the planar body 76 of the electrical insulator 22. The tabs 88 are thus distributed around a periphery, for example an outer periphery, of the outer frame 78 of the electrical insulator 22. In embodiments, any number of tabs 88 may be provided on the outer frame 78 of the electrical insulator 22. The number of tabs 88 provided on the outer frame 78 of the electrical insulator 22 corresponds to the number of tab-shaped wall portions 73 provided on the second terminal 20.

[0078] In embodiments, the size, for example, the surface area or length, of each of the tabs 88 of the electrical insulator 22 may be increased or decreased according to the number of tabs 88 that are provided on the outer frame 78, to the size and / or the shape of the electrical insulator 22 and / or with one or more other requirements of the battery cell 10. The size, for example the surface area or length, of tabs 88 provided on the electrical insulator 22 corresponds to the size, for example the surface area or length, of the wall-shaped tab portions 73 provided on the second terminal 20. Similarly, the size, for example the surface area or length, of the gaps 89 in the outer frame 78 of the electrical insulator 22 corresponds to the size, for example the surface area or length, of the recesses 72 in the outer frame 70 of the second terminal 20.

[0079] As shown in Figures 2 and 6, each of the tabs 88 is generally trapezoid in plan view. In embodiments, the tabs 88 may be any shape in plan view, for example the tabs may be circular, triangular, quadrilateral or any two dimensional polygon shape in plan view. The shape of tabs 88 provided on the electrical insulator 22 corresponds to the shape of the tab-shaped wall portions 73 provided on the outer frame 70 of the second terminal 20. Similarly, the shape of gaps 89 between the tabs 88 of the electrical insulator corresponds to the shape of the recesses 72 of the second terminal 20.

[0080] The first cover layer 24 is a planar structure that is generally rectangular in plan view and includes a sheet of material, for example a sheet of aluminium or a sheet of an aluminium-coated polymeric material. As shown in Figure 11 , the first cover layer 24 has a first or outer face 97 and a second, opposing, inner face 98. The outer edge or boundary 100 of the first cover layer is castellated and includes a number of tabs 102 which are separated by a number of castellations or gaps 103.

[0081] In the same way, the second cover layer 26 is a planar structure that is generally rectangular in plan view and includes a sheet of material, for example a sheet of aluminium or a sheet of an aluminium-coated polymeric material. As also shown in Figure 11, the second cover layer 26 has a first or inner face 105 and a second, opposing, outer face 104. The outer edge or boundary 106 of the second cover layer 26 is castellated and includes a number of tabs 108 which are separated by a number of castellations or gaps 109.

[0082] The battery cell 10 includes a pair of plugs 99a, 99b that are configured to fit in and close the holes 57, 71 as is described below.

[0083] Assembly of the battery cell 10 will now be described.

[0084] The terminal structure 16 is assembled as follows.

[0085] The first terminal 18 is positioned within the first hollow or cavity (not shown) defined by the outer frame 78 on the first face 81 of the electrical insulator 22. The second face 52 of the first terminal 18 is received within the first hollow or cavity (not shown) and contacts, for example is connected or adjoined to, the first face 81 of the electrical insulator 22. The opening 65 of the first terminal 18 is aligned with the first opening 94 of the planar body 76 of the electrical insulator 22. The first edge 84 of the outer frame 78 of the electrical insulator 22 abuts the smooth edge 64 of the castellated portion 58 on the outer frame 56 of the first terminal 18. The first terminal 18 is bonded or adhered or otherwise rigidly fixed to the electrical insulator 22. The bonding agent or adhesive may be applied to the planar body 54 and / or the outer frame 56 of the first terminal 18 and / or the planar body 76 and / or the outer frame 78 of the electrical insulator 22 according to the structural and sealing requirements of the battery cell 10.

[0086] In embodiments of the invention, a physical interlocking connection may be provided between the castellated portion 58 on the outer frame 56 of the first terminal 18 and the outer frame 78 of the electrical insulator 22. The physical interlocking connection may be, for example an interference fit, a snap fit, a friction fit or a press fit, between an element or component of the outer frame 56 of the first terminal 18, for example an element or component of the castellated portion 58, and a complementary element or component of the outer frame 78 of the electrical insulator 22.

[0087] In some embodiments of the invention, the first terminal 18 may be fixedly attached to the electrical insulator 22 by a combination of bonding or adhering and physical interlocking of the first terminal 18 and the electrical insulator 22.

[0088] The second terminal 20 is positioned within the second hollow or cavity 80 defined by the outer frame 78 on the second side or face 82 of the electrical insulator 22. The first face 67 of the second terminal 20 is received within the second hollow or cavity 80 and contacts, for example is connected or adjoined to, the second face 82 of the electrical insulator 22. The opening 75 of the second terminal 20 is aligned with the second opening 90 of the planar body 76 of the electrical insulator 22. The outer frame 70 of the second terminal 20 is positioned within the outer frame 78 of the electrical insulator 22 such that the tabs 88 of the outer frame 78 of the electrical insulator 22 extend over, and cover, the tab-shaped wall portions 73 of the outer frame 70 of the second terminal 20. The castel lations or gaps 89 of the outer frame 78 of the electrical insulator 22 are aligned with the recesses 72 of the outer frame 70 of the second terminal 20 such that the outer frame 70 of the second terminal 20 is exposed, or uncovered, in the region of the recesses 72. The second terminal 20 is bonded or adhered or otherwise rigidly fixed to the electrical insulator 22. The bonding agent or adhesive may be applied to the planar body 68 and / or the outer frame 70 of the second terminal 20 and / or the planar body 76 and / or the outer frame 78 of the electrical insulator 22 according to the structural and sealing requirements of the battery cell 10.

[0089] In embodiments of the invention, a physical interlocking connection may be provided between the outer frame 70 of the second terminal 20 and the outer frame 78 of the electrical insulator 22. The physical interlocking connection may be, for example an interference fit, a snap fit, a friction fit or a press fit, between an element or component of the outer frame 70 of the second terminal 20, and a complementary element or component of the outer frame 78 of the electrical insulator 22.

[0090] In some embodiments of the invention, the second terminal 20 may be fixedly attached to the electrical insulator 22 by a combination of bonding or adhering and physical interlocking of the second terminal 20 and the electrical insulator 22.

[0091] The first and second electrode stacks 12, 14 are assembled on the terminal structure as follows.

[0092] The first electrode stack 12 is positioned within the outer frame 56 of the first terminal 18 such that the second face 30 of the first electrode stack 12 is adjacent to and in contact with the first face 51 of the planar body 54 of the first terminal 18. The outer frame 56 of the first terminal 18 surrounds the periphery of the first electrode stack 12. The first connector portion 32 of the first electrode stack 12 is connected, for example by welding, to the first face 51 of the planar body 54 of the first terminal 18, as shown in Figure 8. The second electrode connector portion 36 of the first electrode stack 12 is passed through the opening 65 in the first terminal 18 and the first opening 94 in the electrical insulator 22 and connected, for example by welding, to the first face 67 of the second terminal 20, as shown in Figure 7.

[0093] Similarly, the second electrode stack 14 is positioned within the outer frame 70 of the second terminal 20 such that the first face 41 of the second electrode stack 14 is adjacent to and in contact with the second face 66 of the planar body 68 of the second terminal 20. The outer frame 70 of the second terminal 20 surrounds the periphery of the second electrode stack 14. The second electrode connector portion 48 of the second electrode 14 is connected, for example by welding, to the second face 66 of the planar body 68 of the second terminal 20, as shown in Figure 7. The first electrode connector portion 44 of the second electrode 14 is passed through the opening 75 in the second terminal 20 and the second opening 90 in the electrical insulator 22 and connected, for example by welding, to the second face 52 of the first terminal 18, as shown in Figure 8.

[0094] Since the first electrode connector portion 32 of the first electrode stack 12 and the first electrode connector portion 44 of the second electrode stack 14 are each the same, first, polarity, the first terminal 18 to which the first electrode connector portion 32 and the first electrode connector portion 44 are connected is also at the first polarity.

[0095] Likewise, since the second electrode connector portion 36 of the first electrode stack 12 and the second electrode connector portion 48 of the second electrode stack 14 are each the same, second, polarity, the second terminal 20 to which the second electrode connector portion 36 and the second electrode connector portion 48 are connected is also at the second polarity. The direct connection between the first and second electrode stacks 12, 14 and the firstand second terminals 18, 20 enables improved connectivity between the active material stacks of the electrode stacks 12, 14 and the terminals 18, 20. The respective faces of each of the electrodes and the corresponding planar bodies of the terminals provide a larger surface area for connection compared to the connection between electrodes and terminals in conventional battery cells. The improved connectivity enables larger electrical and thermal paths to be provided within the battery cell 10. The electrical performance of the battery cell 10 is enhanced such that it is particularly suitable for high current applications, for example automotive applications. The larger thermal paths provided by the metallic terminals 18, 20 within the battery cell 10 ensure that heat can be dissipated within the battery cell 10 to prevent unwanted temperature rises, thereby improving the thermal performance of the battery cell 10, which is also advantageous for automotive applications. The larger thermal paths also ensure that, if required, the temperature of the battery cell 10 can be increased.

[0096] By surrounding the periphery of the respective electrode stacks 12, 14, the outer rims or frames 56, 70 of the first terminal 18 and the second terminal 20 protect the active material within the first and second electrode stacks 12, 14 and enhance the structural integrity of the battery cell 10. The metallic terminal structures 18, 20 form part of the outer boundary of the battery cell 10 and hence present a significantly larger surface area to enable the battery cell 10 to be connected to an adjacent battery cell.

[0097] The second or inner face 98 of the first cover layer 24 is positioned adjacent to the first face (not visible in Figure 2) of the first electrode stack 12 and pressed into position such that the castellations or gaps 103 on the outer edge or boundary 100 of the first cover layer 24 are aligned with the tabs 62 of the castellated portion 58 on the outer frame 56 of the first terminal 18. The first cover layer 24 is bonded or adhered or welded or otherwise sealingly fixed to the first terminal 18. The bonding agent or adhesive may be, for example, applied to first terminal 18 and / or the first cover layer 24 according to the structural and sealing requirements of the battery cell 10.

[0098] In embodiments of the invention, a physical interlocking connection may be provided between the first terminal 18 and the first cover layer 24. The physical interlocking connection may be, for example an interference fit, a snap fit, a friction fit or a press fit, between an element or component of the first terminal 18 and a complementary element or component of the first cover layer 24.

[0099] In some embodiments of the invention, the first cover layer 24 may be fixedly attached to the first terminal 18 by a combination of bonding or adhering and physical interlocking of the first cover layer 24 to the first terminal 18.

[0100] Likewise, the first or inner face 105 (not visible in Figure 2) of the second cover layer 26 is positioned adjacent to the second face 42 of the second electrode stack 14 and pressed into position such that the castellations or gaps 109 on the outer edge or boundary 106 of the second cover layer 26 are aligned with the recesses 72 on the outer frame 70 of the second terminal 20. The second cover layer 26 is bonded or adhered or welded or otherwise sealingly fixed to the second terminal 20. The bonding agent or adhesive may be, for example, applied to the second terminal 20 and / or the second cover layer 26 according to the structural and sealing requirements of the battery cell 10.

[0101] In embodiments of the invention, a physical interlocking connection may be provided between the second terminal 20 and the second cover layer 26. The physical interlocking connection may be, for example an interference fit, a snap fit, a friction fit or a press fit, between an element or component of the second terminal 20 and a complementary element or component of the second cover layer 26. In some embodiments of the invention, the second cover layer 26 may be fixedly attached to the second terminal 20 by a combination of bonding or adhering and physical interlocking of the second cover layer 26 to the second terminal 20.

[0102] The castellated portion 58, including tabs 62, of the first terminal 18, the recesses 72 of the second terminal 20 and the outer frame 78 of the electrical insulator 22 thus form an outer wall 112 of the battery cell 10. The portion of the terminal structure 16 which forms the outer wall 112 of the battery cell 10 thus includes a portion of the first terminal 18 and a portion of the second terminal 20 such that the outer wall 112 of the battery cell 10 includes an integrated first terminal connection, for example a first terminal connection portion 114, and an integrated second terminal connection, for example a second terminal connection portion 116. The first terminal connection portion 114 and the second terminal connection portion 116 thus form first and second portions of the outer wall 112 of the battery cell 10.

[0103] The exposed tabs 62 also form integrated first terminal connector portions 114 of the first terminal 18 of the battery cell 10. The first terminal 18 thus includes a plurality of first terminal connector portions 114. Similarly, the exposed recesses 72 also form integrated second terminal connector portions 116 of the second terminal 20 of the battery cell 10. The second terminal 20 thus includes a plurality of second terminal connector portions 116.

[0104] As described above, the exposed tabs 62 and the exposed recesses 72 are distributed around the outer wall 112 of the battery cell 10. The integrated first terminal connector portions 114 and the integrated second terminal connector portions 116 are therefore also distributed around the outer wall 112 of the battery cell 10.

[0105] In embodiments, the first terminal 18 is one of a positive terminal or a negative terminal and the second terminal 20 is the other of a positive terminal or a negative terminal.

[0106] The first terminal connector portions 114 are the same polarity as the first terminal 18. In other words, if the first terminal 18 is a positive terminal, then the first terminal connector portions 114 are positive terminal connector portions. Likewise, if the first terminal 18 is a negative terminal, then the first terminal connector portions 114 are negative terminal connector portions.

[0107] The second terminal connector portions 116 are the same polarity as the second terminal 20. In other words, if the second terminal 20 is a positive terminal, then the second terminal connector portions 116 are positive terminal connector portions. Likewise, if the second terminal 20 is a negative terminal, then the second terminal connector portions 116 are negative terminal connector portions.

[0108] The holes 57, 71 are provided so that, depending on the type of battery the battery cell 10 is designed for, access is available either for an electrolyte to be added to the chambers formed between the respective terminals 18, 20 and cover layers 24, 26 within which the electrode stacks 12, 14 are accommodated, or for air to be removed from the chambers. The plugs 99a, 99b enable the holes 57, 71 to be closed and sealed.

[0109] The assembly of a battery cell stack 200 from two or more battery cells 10, for example a first battery cell 10a and an adjacent second battery cell 10b will now be described with particular reference to Figure 11.

[0110] A first battery cell 10a and an adjacent second battery cell 10b are positioned such that the second outer face 104 of the second cover layer 26 of the first battery cell 10a is adjacent to the first outer face 97 of the first cover layer 24 of the second adjacent battery cell 10b. The first terminal connector portions 114 formed by the tabs 62 of the first terminal 18 of the second battery cell 10b can then be aligned with the second terminal connector portions 116 formed by the recesses 72 of the second terminal 20 of the first battery cell 10a.

[0111] In this way, the first terminal connector portions 114 of the first terminal 18 of the second battery cell 10b overlap the second terminal connector portions 116 of the second terminal 20 of the first battery cell 10a.

[0112] Since the shape and dimensions of the recesses 72, which form the second terminal connector portions 116 of the second terminal 20 corresponds to the shape and dimensions of the tabs 62, which form the first terminal connector portions 114 of the first terminal 18, the second terminal connector portions 116 of the first battery cell 10a are configured to receive the first terminal connector portions 114 of the second battery cell 10b. In this way, the first terminal connector portions 114 of the second battery cell 10b can connect to, or interlock with, the second terminal connector portions 116 of the first battery cell 10a. The receipt of the first terminal connector portions 114 of the second battery cell 10b within the second terminal connector portions 116 of the first battery cell 10a enables the formation of a structural and electrical connection between the first and second battery cells 10a, 10b.

[0113] In embodiments, the tabs 62 of the first terminal 18 include a first integral attachment feature and the recesses 72 of the second terminal 20 include a second integral attachment feature. The first integral attachment features and the second integral attachment features are configured to cooperate with each other in order to provide connections between the first terminal 18 of the second battery cell 10b and the second terminal 20 of the first battery cell 10a.

[0114] In embodiments, the first terminal connector portions 114 of the first terminal 18 of the second battery cell 10b are joined to the second terminal connector portions 116 of the second terminal 20 of the first battery cell 10a.

[0115] This arrangement advantageously removes the need to provide separate connectors, for example busbars, to enable connection of the adjacent battery cells. Advantageously, this improves the reliability of the battery cell stack.

[0116] The or each first terminal connector portion 114 on a battery cell 10 may be joined to the or each second terminal connector portion 116 on an adjacent battery cell 10 by any suitable joining means. The join may be, for example an interference fit, a snap fit, a friction fit or a press fit between the or each first terminal connector portion 114 on one of the battery cells 10 and the or each second terminal connector portion 116 on the adjacent battery cell 10.

[0117] Alternatively, the join may be provided by welding or brazing or soldering the or each first terminal connector portion 114 of a battery cell 10 to the or each second terminal connector portion 116 of an adjacent battery cell 10.

[0118] In some embodiments, the join may be provided by a combination of an interference fit, a snap fit, a friction fit or a press fit between the or each first terminal connector portion 114 on one of the battery cells 10 and the or each second terminal connector portion 116 on the adjacent battery cell 10 and welding or brazing or soldering the or each first terminal connector portion 114 of the first battery cell 10 to the or each second terminal connector portion 116 of the adjacent battery cell 10. The arrangement of the first and second terminal connector portions 114, 116 around the outer wall 112 of the battery cell 10 also increases the surface area available for termination and thus the battery cell 10 is suitable for high current applications, for example automotive applications.

[0119] Referring again to Figure 11 it can be seen that the outer edges of the second cover layer 26 of the first battery cell 10a and the outer edges of the first cover layer 24 of the second battery cell 10b are sandwiched between the outer frame 56 of the first terminal 18 of the second battery cell 10b and the outer frame 70 of the second terminals 20 of the first battery cell 10a. A gap 25 is defined between a central portion of the second cover layer 26 of the first battery cell 10a and a central portion of the first cover layer 24 of the second battery cell 10b. The central portion of the second cover layer 26 is spaced apart from outer edges of the second cover layer 26 and so is also spaced apart from the outer frame 56 of the first terminal 18 of the second battery cell 10b and the outer frame 70 of the second terminals 20 of the first battery cell 10a. Similarly, the central portion of the first cover layer 24 is spaced apart from outer edges of the first cover layer 24 and so is also spaced apart from the outer frame 56 of the first terminal 18 of the second battery cell 10b and the outer frame 70 of the second terminals 20 of the first battery cell 10a. Since the central portions of the first cover layer 24 and the second cover layer 26 are not sandwiched between the outer frame 56 of the first terminal 18 of the second battery cell 10b and the outer frame 70 of the second terminals 20 of the first battery cell 10a, the central portions of the first cover layer 24 and the second cover layer 26 are able to flex or self-jig in order to accommodate movement and / or changes in the size or shape of other components within a battery cell stack 200. The gap 25 advantageously accommodates swelling and expansion of the electrode stacks 12, 14. The arrangement of the battery cell stack 200 thus removes the need for additional components such as spacers and fillers, reducing the complexity of the battery cell stack and eliminating the tolerance issues arise from the inclusion of additional components within a battery cell stack 200.

[0120] In embodiments of the invention, the gap 25 may be filled with a compressive material which may be, for example, an expanding foam. Such a compressive material would advantageously provide a preload to the battery cell and increase the compressive forces a battery cell 10 can withstand over its lifetime.

[0121] With particular reference to Figures 9 and 10, a battery cell stack 200 may include an end plate 202, for example a battery frame or a cooling plate support structure. Providing an end plate 202 at each end of the battery cell stack 200 further improves the structural integrity of the battery cell stack 200 by eliminating cell to cell forces, particularly cell to cell forces generated when a compressive material is provided within the gap 25 defined between the second cover layer 26 of a first battery cell 10a and the first cover layer 24 of a second battery cell 10b.

[0122] The metallic planar bodies 54, 68 of the first and second terminals 18, 20 increase the stiffness and further enhance the structural integrity of the battery cell 10, as well as improving the thermal performance of the battery cell 10.

[0123] The sandwich arrangement of the battery cell 10 with the nesting of adjacent components or layers of the battery cell 10 also provides efficient packing of the battery cell volume, thereby improving the performance of the battery cell 10.

[0124] The sandwich cell construction of the battery cell 10 of the present invention also removes the need for additional components to ensure electrical and mechanical connection of battery cells 10 within a battery cell stack or a battery. This is advantageous as it reduces the number of parts required, and enables the efficiency use of the volume occupied by a battery, as well as a reduction in the mass of the battery. This is particularly beneficial for automotive applications in which it is desirable to reduce the overall mass of components.

[0125] As described above, the recesses 72 of the second terminal 20 of a battery cell 10 are shaped and sized to receive the tabs 62 of the first terminal 18 of an adjacent battery cell 10. The tabs 62, which form integrated first terminal connector portions 114, on the periphery or outer wall of the adjacent battery cell nest within and / or interlock with the recesses 72, which form integrated second terminal connector portions 116, on the periphery or outer wall 112 of the battery cell 10 creating a tightly packed assembly with minimal spacing and loss of volume.

[0126] As shown in Figures 9, 10 and 11, the interconnecting and interlocking terminal connection portions 114, 116 enable the electrical and mechanical connection of adjacent battery cells without the need for additional parts to connect one battery cell to another in order to create a chain or battery cell stack. The electrical and mechanical connection between adjacent battery cells in a battery cell stack is more robust than is possible with convention terminals, which require separate electrical connectors, e.g. busbars, and / or mechanical connectors, such as frames, for connecting adjacent battery cells.

[0127] The mechanical connection between interlocked tabs and recesses may be enhanced by any suitable joining method, for example welding or soldering, or by the provision of integral attachment features to enable a snap, friction or interference fit between respective tabs and recesses. As described above, the first terminal connector portions 114 of the first terminal 18 overlap the second terminal connector portions 116 of the second terminal 20. The overlapping surfaces, or terminal connector portions 114, 116, may be welded or soldered together and / or may include integral attachment features to enable a snap, friction, or interference fit between the tabs 62 of one battery cell 10 and the recesses 72 of an adjacent battery cell.

[0128] It will be appreciated that the number and size of the tabs 62 and recesses 72 can be increased or decreased according to the performance requirements of a battery including the battery cells 10.

[0129] The sandwich construction of the present invention advantageously enables any number of battery cells 10 to be connected in series, as described above, to form a battery cell stack 200 or a battery.

[0130] The increased surface area at the connection between the electrode stacks 12, 14 and respective terminals 18, 20 of the sandwich cell construction enables larger thermal paths to be provided within the battery cell 10. The larger thermal paths ensure that heat can be dissipated within the battery cell 10 to prevent unwanted temperature rises, thereby improving the thermal performance of the battery cell 10. The enhanced thermal paths within the battery cell 10 ensure a more homogenous temperature distribution within a battery cell stack 200 of battery cells 10, since neighbouring battery cells 10 can also wick heat away.

[0131] Conversely if, for operational reasons, it is desired to increase the temperature of the components within the battery cell 10, the improved thermal paths within the battery cell 10 enable this.

[0132] It will be appreciated that the battery cell 10 includes fewer components than conventional battery cells and so is less complex to manufacture and enables the overall mass of a battery to be reduced. Figure 12 illustrates a vehicle 300 according to an embodiment of the present invention. The vehicle 300 includes a battery cell stack 200 as illustrated in Figures 9 to 11, which comprises a plurality of battery cells 10 as illustrated in Figures 1 to 8.

[0133] It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

CLAIMS1. A battery cell comprising: a first electrode stack; a second electrode stack; and a terminal structure sandwiched between and connected to each of the first electrode stack and the second electrode stack; wherein the terminal structure comprises: a first terminal, being one of a positive terminal or a negative terminal; a second terminal, being the other of a positive terminal or a negative terminal; and an electrical insulator sandwiched between and connected to each of the first terminal and the second terminal; and wherein a portion of the terminal structure forms an outer wall of the battery cell, which outer wall surrounds an outer periphery of each of the first electrode stack and the second electrode stack.

2. A battery cell according to claim 1 , wherein the first terminal comprises a first terminal planar body and a first terminal outer frame extending around an outer periphery of the first terminal planar body and wherein one of the first electrode stack and the second electrode stack contacts the first terminal planar body within the first terminal outer frame.

3. A battery cell according to claim 2, wherein the second terminal comprises a second terminal planar body and a second terminal outer frame extending around an outer periphery of the second terminal planar body and wherein the other of the first electrode stack and the second electrode stack contacts the second terminal planar body within the second terminal outer frame.

4. A battery cell according to any of claims 1 to 3, wherein the electrical insulator of the terminal structure comprises an electrical insulator planar body and an electrical insulator outer frame extending around an outer periphery of the electrical insulator planar body and wherein one of the first terminal and the second terminal contacts the electrical insulator planar body within the electrical insulator outer frame.

5. A battery cell according to claim 4, wherein the first terminal contacts a first face of the electrical insulator and the second terminal contacts a second opposing face of the electrical insulator.

6. A battery cell according to claim 4 or claim 5, wherein the electrical insulator planar body comprises an opening and the first terminal planar body comprises a first terminal opening; and wherein a first electrode connector portion of one of the first electrode stack and the second electrode stack is connected to the first terminal and a second electrode connector portion of the one of the first electrode stack and the second electrode stack extends through the opening in the electrical insulator planar body and the first terminal opening and is connected to the second terminal.

7. A battery cell according to claim 6, wherein the opening in the electrical insulator planar body is a first opening; whereinthe electrical insulator planar body comprises a second opening and the second terminal planar body comprises a second terminal opening; and wherein a first electrode connector portion of the other of the first electrode stack and the second electrode stack is connected to the second terminal and a second electrode connector portion of the other of the first electrode stack and the second electrode stack extends through the second opening in the electrical insulator planar body and the second terminal opening and is connected to the first terminal.

8. A battery cell according to claim 7, wherein each electrode stack comprises interleaved negative polarity generating plates and positive polarity generating plates, each of the negative polarity generating plates being connected together at one end of the electrode stack to form said first or second electrode connector portion and each of the positive polarity generating plates being connected together at another end of the electrode stack to form the other of said first or second electrode connector portion, and the openings in the electrical insulator planar body and the respective one of the first and second terminal openings are aligned with the respective first and second electrode connector portions at the ends of each electrode stack.

9. A battery cell according to claim 3, or any of claims 4 to 8 when dependent on claim 3, wherein the first terminal outer frame comprises one of a tab and a recess and the second terminal outer frame comprises the other of the tab and the recess, and wherein the recess is configured to receive a tab of an adjacent battery cell.

10. A battery cell according to claim 9, wherein the first terminal outer frame comprises one of a plurality of tabs or a plurality of recesses or a combination of tabs and recesses, and the second terminal outer frame comprises the other of the plurality of tabs, the plurality of recesses and a combination of tabs and recesses, wherein the plurality of tabs, the plurality of recesses and combination of tabs and recesses are distributed around a periphery of the respective outer frames.

11. A battery cell according to claim 9 or 10, wherein the or each tab and the or each recess form terminal connector portions for the respective terminals.

12. A battery cell according to any preceding claim, wherein the portion of the terminal structure which forms the outer wall of the battery cell comprises a portion of the first terminal and a portion of the second terminal such that the outer wall of the battery cell comprises an integrated first terminal connector portion and an integrated second terminal connector portion.

13. A battery cell according to claim any preceding claim, wherein the first electrode stack, the second electrode stack and the terminal structure are sandwiched between a first cover layer and a second cover layer.

14. A battery cell stack comprising one or more battery cells according to any of claims 1 to 13.

15. A vehicle comprising one or more battery cells according to any of claims 1 to 13, or a battery cell stack according to claim

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