Terminal for a battery cell, and prismatic battery cell

Abstract

The invention relates to a terminal (2, 3) for a battery cell (1), the terminal being intended to be placed in electrical connection with a current collector (10) of the battery cell (1), the terminal (2, 3) comprising a plate (71) and a cruciform imprint (73) protruding from the plate (71), the imprint (73) being intended to interact via interference fitting with a counter-imprint (63) defined by the spacing member (15), in such a way as to block a relative translation and a relative rotation between the terminal (2, 3) and the spacing member (15). The invention also relates to an assembly (5), and to a battery cell (1) comprising such a terminal (2, 3).

Description

[0001] DESCRIPTION

[0002] TITLE: Terminal for battery cell, and prismatic battery cell

[0003] Technical field of the invention

[0004] The present invention relates to the field of electric battery cells, in particular prismatic battery cells.

[0005] More specifically, the invention relates to a terminal for such a battery cell.

[0006] State of the art

[0007] In the field of secondary batteries, and particularly batteries for electric vehicles, it is common to manufacture so-called prismatic battery cells. Their shape allows them to be easily stacked side by side, which is especially advantageous for building an electric vehicle battery. Generally, such battery cells consist of two electrodes: an anode and a cathode, which are in the form of sheets. These electrodes are then stacked to form one or more electrode stacks that make up the prismatic battery cell. A porous separator is placed between the anode and the cathode. The electrode stack is then inserted into a rigid casing that serves to protect the electrode stack and to allow the insertion of an electrolyte, which facilitates ion transport between the two electrodes.

[0008] To maximize battery cell capacity, it is known to create two stacks of electrodes designed to be inserted inside the same battery cell casing. Furthermore, the prismatic battery cell includes two terminals, located on the lid side, which are used to make electrical connections with other battery cells.

[0009] To carry the current produced by the electrode stacks to these terminals, it is known in the prior art to use a current collector for each terminal. These current collectors are electrically connected to each type of electrode. They must ensure efficient and reliable collection of the current produced by the electrodes of a given type. Therefore, there is generally one current collector dedicated to collecting the current from the anodes, and another current collector dedicated to collecting the current from the cathodes.

[0010] Once current collection is complete, it is necessary to ensure that the assembly formed by the electrodes and current collectors is securely fixed inside the casing, to limit any movement of the stack relative to the casing, under normal battery operating conditions.

[0011] Therefore, to ensure optimal performance of a prismatic battery cell, precise positioning of the stacks relative to the current collectors and the casing is essential. This positioning is a critical step in the positioning process, particularly for large-scale production.

[0012] Furthermore, to prevent short circuits between two electrodes of opposite polarity, the battery cell includes insulating elements that electrically isolate various conductive parts of the battery cell. This is particularly true of the battery cell cover, which ensures a watertight seal. A key challenge, therefore, lies in determining whether or not to electrically isolate the battery cell cover from the current collector(s) and from each terminal of the battery cell. In addition to its potential electrical insulation function, such an insulating element must also allow for gas venting and enable the relative positioning of adjacent components, while simultaneously allowing for the formation of a compact system suitable for insertion into the battery cell.

[0013] Given the limited space remaining in the casing of a battery cell, the sizing of each element of the battery cell to form a compact system, capable of being simply positioned in the casing of the battery cell, remains improvable.

[0014] Object of the invention

[0015] The present invention aims to provide a solution that addresses all or part of the aforementioned problems.

[0016] This goal can be achieved through the implementation of a battery cell terminal intended to be placed in electrical connection with a current collector of the battery cell, said terminal comprising a plate and a cross-shaped indentation projecting from the plate, the indentation comprising a lower face intended to come into contact with a spacer element, and the plate comprising a upper face opposite to the lower face, and intended to allow an electrical connection with elements external to the battery cell; terminal in which the indentation is intended to cooperate by complementary shape with a counter-indentation delimited by the spacer element, in such a way as to block relative translation and relative rotation between the terminal and the spacer element.

[0017] The previously described features allow for the design of a battery cell terminal with a footprint that complements the shape of a counter-footprint for a battery cell spacer. This enables the terminal to be positioned relative to the battery cell cover while maintaining a compact overall design. Synergistically, the cross-shaped footprint acts as a keying feature for assembling the components of the prismatic battery cell. In other words, the footprint forms a cross-shaped bump.

[0018] Thus, the impression protrudes out of a plane of elongation of the plate, which facilitates its insertion towards the spacer organ.

[0019] The terminal may also have one or more of the following characteristics, taken alone or in combination.

[0020] According to one embodiment, the impression comprises four branches all extending in a plane of elongation of the plate, said four branches comprising two longitudinal branches extending along a longitudinal direction, and two transverse branches extending along a transverse direction perpendicular to the longitudinal direction.

[0021] Thus, the cross shape of the footprint is suitable for alignment with the axes of the battery cell, when the latter has a prismatic shape.

[0022] According to one embodiment, the two longitudinal branches are identical, and / or the two transverse branches are identical.

[0023] Thus, it is possible to manufacture, using the same process, a terminal intended to be placed on the anode or cathode side.

[0024] According to one embodiment, a width of the transverse branches measured substantially along the longitudinal direction is strictly greater than twice a width of the longitudinal branches measured substantially along the transverse direction.

[0025] Thus, this provides greater resistance to rotation between the spacer and the battery cell terminal, and it provides a keying feature for positioning the terminal relative to the spacer.

[0026] According to one embodiment, the terminal includes a through contact opening intended to allow the passage of a contact element through the impression and the plate.

[0027] The terminal thus includes means for connecting a current collector with said terminal by passing through the spacing element.

[0028] According to one embodiment, the transverse direction is the perpendicular bisector of a segment defined between the ends of each of the longitudinal branches, the through opening then being arranged on the transverse direction.

[0029] Thus, it is possible to pre-position the battery cell terminal transversely relative to the cover, and therefore relative to the battery cell casing.

[0030] According to one embodiment, the through contact opening is a circular opening.

[0031] In this way, the contact opening is adapted to allow the passage of a contact element having a geometry of revolution around a lateral direction corresponding to the direction of insertion of the electrode assemblies into the battery cell casing. Such a contact element could, for example, be a rivet.

[0032] According to one embodiment, the longitudinal direction is the perpendicular bisector of a segment defined between the ends of each of the transverse branches, a center of the contact opening being offset from a center of the cross shape of the imprint, said center of the cross shape of the imprint corresponding to an intersection of the longitudinal direction and the transverse direction.

[0033] Thus, the position of the contact opening allows us to define the positioning that the terminal takes in relation to the cover.

[0034] According to one embodiment, the terminal includes a support collar surrounding the contact opening on the side where said contact opening emerges from the upper face, said support collar defining a bearing surface on which a contact member is intended to bear.

[0035] The support collar thus allows the contact element to be tightened when it rests on the support surface, which improves the fixing of the terminal with the cover, but also with the current collector with which the terminal is intended to be electrically connected.

[0036] According to one embodiment, the plate is substantially in the shape of a rectangular parallelepiped, and has a terminal length measured along the longitudinal direction and a terminal width measured along the transverse direction, said terminal length being strictly greater than the terminal width.

[0037] Thus, the terminal is suitable for use with a prismatic battery cell. This allows for simpler positioning of the battery cell terminal relative to the other battery cell components, particularly the spacer element.

[0038] According to one embodiment, the terminal comprises or is made of aluminium, or of an aluminium alloy, in particular aluminium alloy AL3003 or aluminium alloy AL1050.

[0039] Such a material is particularly suitable for enabling and controlling the passage of current on the cathode side.

[0040] The object of the invention can also be achieved through the implementation of an assembly for a prismatic electric battery cell comprising: a terminal as described above; a cover intended to ensure a watertight closure of a battery cell housing; and a spacer intended to be interposed between the cover and the terminal, said spacer comprising a counter-imprint cooperating with the imprint of the terminal to block relative translation and relative rotation with the terminal.

[0041] The arrangements described above make it possible to form an assembly ready to be associated with electrode assemblies to form the prismatic battery cell.

[0042] The object of the invention can also be achieved through the implementation of a prismatic battery cell for an electric propulsion vehicle, said battery cell comprising: a casing having a prismatic shape, the casing having a top opening and internally delimiting a casing housing; at least one electrode assembly disposed in the casing housing and comprising the successive assembly of first and second electrodes of opposite polarity and separated from each other by a porous separator film; an assembly as described above, in which the cover ensures a tight seal of the top opening of the casing; a first current collector electrically connected to the first electrodes; a second current collector electrically connected to the second electrodes; and a solid or liquid electrolyte.

[0043] The previously described provisions allow for the design of a battery cell in which the spacer facilitates the positioning of the terminal relative to the cover. This enables the formation of a compact assembly that fits the dimensions of the battery cell casing.

[0044] Brief description of the drawings

[0045] Other aspects, objectives, advantages, and features of the invention will become clearer upon reading the following detailed description of preferred embodiments thereof, given by way of non-limiting example, and made with reference to the accompanying drawings in which:

[0046] Figure 1 is a schematic perspective view of a terminal according to the invention, viewed from the top side.

[0047] Figure 2 is a schematic view of the terminal in Figure 1, viewed from the underside.

[0048] Figure 3 is a schematic exploded and perspective view of an assembly according to the invention.

[0049] Figure 4 is a schematic view of a battery cell according to the invention. Detailed description

[0050] In the figures and throughout the description, the same reference numerals represent identical or similar elements. Furthermore, the various elements are not drawn to scale to ensure clarity. Moreover, the different embodiments and variants are not mutually exclusive and can be combined.

[0051] As can be seen in figures 1 and 2, the invention relates to a terminal 2, 3 for battery cell 1 intended to be placed in electrical connection with a current collector 10 of the battery cell 1.

[0052] Terminal 2, 3 includes first of all a plate 71, visible in Figure 1, comprising a top face fs71 intended to allow an electrical connection with elements external to the battery cell 1.

[0053] The plate 71 is generally roughly rectangular in shape and has a terminal length L71 measured along a longitudinal direction denoted "X". The plate 71 may also have a terminal width w71 measured along a transverse direction denoted "Y", perpendicular to the longitudinal direction X. The terminal length L71 is advantageously strictly greater than the terminal width w71. Thus, the terminals 2, 3 are suitable for equipping a prismatic battery cell 1, as this simplifies the positioning of the terminals 2, 3 of the battery cell 1 relative to the other elements of the battery cell, and in particular the spacer 15.

[0054] Terminal 2, 3, and in particular plate 71, may be made of the same material as the metal foil of electrode 51, 53 with which terminal 2, 3 is intended to be electrically connected. For example, terminal 2, 3 may comprise or be made of aluminum, or an aluminum alloy, such as aluminum alloy AL3003 or aluminum alloy AL1050. Such a material is particularly suitable for enabling and controlling the flow of current on the cathode side, but may also be used on the anode side.

[0055] Terminal 2, 3 also includes a cross-shaped indentation 73 projecting from plate 71, as shown in Figure 2. In other words, the indentation 73 forms a cross-shaped bump. The indentation 73 has a lower face fi73 designed to contact a spacing element 15. The lower face fi73 is therefore opposite the upper face fs71. The cross-shaped projection of the plate 71 facilitates the insertion of the impression 73 towards the spacer 15. The impression 73 is thus designed to cooperate by complementary shape with a counter impression 63 delimited by the spacer 15, and visible in Figure 3. This makes it possible to block relative translation and relative rotation between the terminal 2, 3 and the spacer 15. According to a non-limiting variant shown in Figure 2, the impression 73 can comprise four arms 72, 74 all extending in a plane of elongation of the plate 71.These four branches can include two longitudinal branches 72 extending along the longitudinal direction X, and two transverse branches 74 extending along the transverse direction Y. Thus, the cross shape of the footprint 73 is suitable for being aligned with axes of the battery cell 1, when the latter has a prismatic shape.

[0056] Moreover, the transverse direction Y can be defined as the perpendicular bisector of a segment extending between the ends of each of the longitudinal branches 72, and the longitudinal direction X can be the perpendicular bisector of a segment extending between the ends of each of the transverse branches 74. The intersection of the longitudinal direction X with the transverse direction Y thus allows us to define a center c73 of the cross shape of the imprint 73.

[0057] Advantageously, the two longitudinal branches 72 can be identical, and / or the two transverse branches 74 can be identical. Thus, it is possible to manufacture, using the same process, a terminal 2, 3 intended to be positioned on the anode or cathode side.

[0058] Furthermore, it is possible that a width L74 of the transverse branches 74 measured approximately along the longitudinal direction X is strictly greater than twice a width L72 of the longitudinal branches 72 measured approximately along the transverse direction Y. Thus, this makes it possible to provide greater resistance to rotation between the spacer 15 and the terminal 2, 3 of the battery cell 1, and this makes it possible to form a positioning key for the terminal 2, 3 with respect to the spacer 15.

[0059] To allow a contact member 11 to pass through the recess 73 and the plate 71, the terminal 2, 3 may be provided with a through contact opening 75, for example, a circular contact opening 75. The terminal 2, 3 thus includes means for connecting a current collector 10 to said terminal 2, 3 by passing through the spacer member 15. Furthermore, the circular shape of the contact opening 75 is adapted to allow the passage of a contact member 11 having a geometry of revolution about a lateral direction Z corresponding to a direction of insertion of the electrode assemblies 50 51, 53 into the housing 4 of the battery cell 1. Such a contact member 11 may, for example, be a rivet.

[0060] As can be seen in Figure 1, the contact opening 75 can be surrounded by a support flange 76 on the side where said contact opening 75 emerges from the upper face fs71. This support flange 76 defines a bearing surface sa76 on which the contact member 11 is intended to bear. The support flange 76 thus allows the contact member 11 to be clamped when it bears against the bearing surface sa76, thereby improving the attachment of the terminal 2, 3 to the cover 6, and also to the current collector 10 with which the terminal 2, 3 is intended to be electrically connected.

[0061] With reference to Figure 2, the contact opening can be arranged and centered on the transverse Y direction. Thus, it is possible to pre-position terminal 2, 3 of battery cell 1 transversely relative to cover 6, and therefore relative to the housing.

[0062] 4 of the battery cell 1. Furthermore, it is possible that a center c75 of the contact opening 75 is offset relative to the center c73 of the cross shape of the imprint 73. Thus, the position of the contact opening 75 allows to define the positioning which the terminal 2, 3 takes relative to the cover 6.

[0063] The arrangements described above allow for a terminal 2, 3 for battery cell 1 comprising a recess 73 with a shape complementary to a counter-recess 63 of a spacer 15 of the battery cell 1. This allows the terminal 2, 3 to be positioned relative to the cover 6 of the battery cell 1, while maintaining a compact assembly. Synergistically, the cross-shaped recess 73 acts as a keying device for arranging the components constituting the prismatic battery cell 1.

[0064] As can be seen in Figure 3, the invention also relates to a set

[0065] 5 for prismatic electric battery cell 1 comprising: a terminal 2, 3 as described previously; a cover 6 intended to ensure a watertight closure of a housing 4 of the battery cell 1; and a spacer 15 intended to be interposed between the cover 6 and the terminal 2, 3.

[0066] In the embodiment shown in Figure 3, the assembly 5 comprises a first terminal 2 and a second terminal 3 of opposite polarity to the first terminal 2. Generally, the first terminal 2 and the second terminal 3 are two separate parts attached to the cover 6. The assembly also includes two spacers 15, one spacer 15 being interposed between each terminal 2, 3 and the cover 6.

[0067] As illustrated, each spacing member 15 includes a counter-imprint 63 cooperating with the imprint 73 of the terminal 2, 3 with which it is associated, to block relative translation and relative rotation with this terminal 2, 3. The arrangements described above make it possible to form an assembly 5 ready to be associated with the electrode assemblies 50 51, 53 to form the prismatic battery cell 1.

[0068] Finally, with reference to Figure 4, the invention also relates to a prismatic battery cell 1 for an electric vehicle. The battery cell 1 comprises a prismatic housing 4. The housing 4 internally delimits a cell compartment 9 and has a top opening 8 that provides access to this cell compartment 9. The cell compartment 9 can extend in the lateral direction Z.

[0069] Battery cell 1 also includes an assembly 5 as previously described, in which the cover 6 ensures a tight seal of the upper opening 8 of the case 4.

[0070] A first current collector 10 is electrically connected to the first terminal 2 and a second current collector 10 is electrically connected to the second terminal 3. The battery cell 1 may advantageously include insulating elements 13 interposed between each current collector 10 and the cover 6. The electrical insulation conferred by the insulating elements 13 prevents any short circuit between the current collectors 10 and the cover 6.

[0071] The battery cell 1 also includes at least one assembly 50 of electrodes 51, 53 comprising the successive assembly of first and second electrodes 51, 53 of opposite polarity and separated from each other by a porous separator film.

[0072] The first electrode 51 may include a first metal foil in the form of a thin strip, onto which a layer of a first active material is deposited. If the first electrode 51 is a cathode, the first metal foil may be aluminum. The second electrode 53 may include a second metal foil in the form of a thin strip, onto which a layer of a second active material is deposited. If the second electrode 53 is an anode, the second metal foil may be copper.

[0073] The insulating separator(s) are arranged so that no electrical contact is possible between the first electrode 51 and the second electrode 53. The insulating separators also have a porous structure, allowing the passage of an electrolyte comprising ions responsible for the charge transfer between the first electrode 51 and the second electrode 53.

[0074] In the particular case of prismatic battery cells 1, the assemblies 50 generally comprise a stacking or winding of the layers previously described, and in particular two stackings or windings, thus forming two distinct assemblies 50 intended to be housed in a single housing 9.

[0075] The first and second electrodes 51, 53 each have a current-collecting tab 55 projecting from the assembly 50 and configured to collect an electric current from said electrode. The first current collector 10 can be electrically connected to the current-collecting tabs 55 of the first electrodes 51, and the second current collector 10 can be electrically connected to the current-collecting tabs 55 of the second electrodes 53. To facilitate current collection by the current collectors 10, it is advantageous for them to be made of the same material as the electrode with which they are electrically connected. Thus, the first current collector 10 can be made of aluminum, and the second current collector 10 can be made of copper.

[0076] Advantageously, the battery cell may include an electrically insulating side element 7 interposed between the electrode assembly 50 51, 53 and the housing 4. In this way, the electrically insulating side element 7 allows the current collection tabs 55 to be electrically isolated from the housing 4 of the battery cell 1.

[0077] Furthermore, it is generally provided that the battery cell 1 includes a contact element 11, such as a rivet, which provides an electrical connection between each terminal 2, 3, and one of the current collectors 10. The contact opening 75 is intentionally provided in the terminals 2, 3, to allow the passage of such a contact element 11.

[0078] Finally, in order to allow the exchange of ions between the first electrode 51 and the second electrode 53, the battery cell 1 generally includes a solid or liquid electrolyte.

[0079] The arrangements described above allow us to propose a battery cell 1 in which the spacer 15 facilitates the positioning of the terminal 2, 3 relative to the cover 6. This allows us to form a compact assembly adjusted to the dimensions of the housing 4 of the battery cell 1.

Claims

DEMANDS 1. Terminal (2, 3) for battery cell (1) intended to be placed in electrical connection with a current collector (10) of the battery cell (1), said terminal (2, 3) comprising a plate (71) and a recess (73) projecting from the plate (71) and in the shape of a cross, the recess (73) comprising a lower face (fi73) intended to come into contact with a spacer element (15), and the plate (71) comprising an upper face (fs71) opposite the lower face (fi73), and intended to allow an electrical connection with elements external to the battery cell (1); terminal (2, 3) in which the impression (73) is intended to cooperate by complementarity of form with a counter impression (63) delimited by the spacing member (15), in a way blocking a relative translation and a relative rotation between the terminal (2, 3) and the spacing member (15).

2. Terminal (2, 3) according to claim 1 or 2, wherein the imprint (73) comprises four branches (72, 74) all extending in an elongation plane of the plate (71), said four branches comprising two longitudinal branches (72) extending along a longitudinal direction (X), and two transverse branches (74) extending along a transverse direction (Y) perpendicular to the longitudinal direction (X).

3. Terminal (2, 3) according to claim 2, wherein the two longitudinal branches (72) are identical, and / or wherein the two transverse branches (74) are identical.

4. Terminal (2, 3) according to claim 3, wherein a width (L74) of the transverse branches (74) measured substantially along the longitudinal direction (X) is strictly greater than twice a width (L72) of the longitudinal branches (72) measured substantially along the transverse direction (Y).

5. Terminal (2, 3) according to any one of claims 1 to 4, comprising a through contact opening (75) intended to allow the passage of a contact member (11) through the imprint (73) and the plate (71).

6. Terminal (2, 3) according to claim 5 and according to any one of claims 2 to 4, wherein the transverse direction (Y) is the perpendicular bisector of a segment defined between the ends of each of the longitudinal branches (72), the through opening then being arranged on the transverse direction (Y).

7. Terminal (2, 3) according to any one of claims 5 and 6, wherein the through contact opening (75) is a circular opening.

8. Terminal (2, 3) according to claims 6 and 7, wherein the longitudinal direction (X) is the perpendicular bisector of a segment defined between the ends of each of the transverse branches (74), a center (c75) of the contact opening (75) being offset with respect to to a center (c73) of the cross shape of the imprint (73), said center (c73) of the cross shape of the imprint (73) corresponding to an intersection of the longitudinal direction (X) and the transverse direction (Y).

9. Terminal (2, 3) according to any one of claims 7 or 8, comprising a support collar (76) surrounding the contact opening (75) on the side where said contact opening (75) opens from the upper face (fs71), said support collar (76) defining a bearing surface (sa76) on which a contact member (11) is intended to bear.

10. Terminal (2, 3) according to any one of claims 1 to 9, wherein the plate (71) is substantially in the shape of a rectangular parallelepiped, and has a terminal length (L71) measured along the longitudinal direction (X) and a terminal width (w71) measured along the transverse direction (Y), said terminal length (L71) being strictly greater than the terminal width (w71).

11. Terminal (2, 3) according to any one of claims 1 to 10, comprising or being made of aluminium, or of an aluminium alloy, in particular aluminium alloy AL3003.

12. Assembly (5) for prismatic electric battery cell (1) comprising: - a terminal (2, 3) according to any one of claims 1 to 11; - a cover (6) intended to ensure a watertight seal of a housing (4) of the battery cell (1); and - a spacing member (15) intended to be interposed between the cover (6) and the terminal (2, 3), said spacing member (15) comprising a counter-impression (63) cooperating with the impression (73) of the terminal (2, 3) to block a relative translation and a relative rotation with the terminal (2, 3).

13. Prismatic battery cell (1) for an electric propulsion vehicle, said battery cell (1) comprising: - a housing (4) having a prismatic shape, the housing (4) having a top opening (8) and internally delimiting a housing compartment (9) - at least one assembly (50) of electrodes (51, 53) arranged in the housing (9) and comprising the successive assembly of first and second electrodes (51, 53) of opposite polarity and separated from each other by a porous separating film; - an assembly (5) according to claim 12, in which the cover (6) ensures a tight seal of the upper opening (8) of the housing (4); - a first current collector (10) electrically connected to the first electrodes (51); - a second current collector (10) electrically connected to the second electrodes (63); and - a solid or liquid electrolyte.

Images