Cover assembly of a battery cell

Abstract

The invention relates to a cover assembly of a battery cell, the cover assembly comprising: a metal base plate (2); a first terminal (3) which is designed as a cathode and is arranged in a through-opening (20) in the base plate (2); a sealing element (5) which secures and seals the first terminal (3) to the base plate (2), wherein the sealing element (5) is made of an electrically conductive material, wherein the sealing element (5) is arranged in the through-opening (20) and is designed to seal a first connection region (6) between the terminal (3, 4) and the sealing element (5) and a second connection region (7) between the base plate (2) and the sealing element (5), and to establish a connection between the first terminal (3) and the base plate (2), and wherein a surface-treated first partial surface (13) and an untreated second partial surface (14) are provided on a first contact surface (31) of the first terminal (3) to the sealing element (5), and / or a surface-treated first partial surface (11) and an untreated second partial surface (12) are provided on a second contact surface (21) in the through-opening (20) of the base plate to the sealing element (5), in such a way that in each case a frictional connection is formed between the base plate (2) and the sealing element (5) and between the first terminal (3) and the sealing element (5).

Description

[0001] March 3, 2025

[0002] Cover assembly of a battery cell

[0003] Description

[0004] The present invention relates to a cover assembly of a battery cell, wherein the cover assembly provides pressure-activated zones to ensure electrical conductivity between a terminal (cathode) and a metallic base plate. Furthermore, the invention relates to a battery cell, in particular a prismatic cell, comprising such a cover assembly.

[0005] Battery cells, such as prismatic cells, are used in rechargeable lithium-ion batteries, sodium-ion batteries, or supercapacitors, for example. The battery cell comprises a housing, which is usually made of aluminum, and a cover assembly that is attached to the housing and closes the housing. The cover assembly therefore has the task of closing and sealing the battery housing in order to protect the environment from the cell chemistry. The cover assembly should also prevent interfering substances such as oxygen or water from outside from entering the cell interior. Furthermore, the cover assembly should enable the connection of electrodes inside the battery cell and electrical contact outside the battery cell. During operation of the battery cell, very hot and very cold operating states can occur.This can interrupt the electrical connection between a terminal used as the battery cell's cathode and a metallic base plate. This electrical connection between the terminal and the metallic base plate serves primarily to protect the cathode from corrosion.

[0006] The object of the present invention is to provide an improved cover assembly that is simple and cost-effective to manufacture and provides a secure electrical connection between a cathode of the cover assembly and a metallic base plate in all operating conditions. Furthermore, the object of the present invention is to provide a battery cell with such a cover assembly.

[0007] This object is achieved by a cover assembly having the features of claim 1 and a battery cell having the features of claim 11.

[0008] The subclaims show preferred developments of the invention. The cover assembly according to the invention with the features of claim 1 has the advantage that reliable electrical contact between the cathode and a metallic base plate is always possible across all temperature ranges that can occur during use of a battery cell. In fact, when temperatures change, the cover assembly may bulge or twist, so that electrical connections between the cathode and the metallic base plate, which are necessary for corrosion protection of the cathode, may become loose or there may be no electrical contact temporarily. This is achieved according to the invention in that a first terminal designed as a cathode is arranged in a through-opening in a base plate.A sealing element is arranged between the base plate and the first terminal, which seals and fastens the first terminal to the base plate. The sealing element is made of an electrically conductive material and thus provides an electrical connection between the first terminal and the metallic base plate. The sealing element arranged in the through-opening is designed to seal a first connection area between the terminal and the sealing element and a second connection area between the base plate and the sealing element, and to provide fixation and electrical connection between the first terminal and the base plate. Furthermore, a first contact surface is provided on the base plate for the sealing element, and a second contact surface of the terminal for the sealing element is provided.The first contact surface and / or the second contact surface each have a surface-treated first partial surface and an untreated second partial surface such that a force-fitting connection is formed between the base plate and the sealing element and / or between the first terminal and the sealing element. These force-fitting connections at the contact areas of the sealing element provide pressure-activated zones and thus ensure that, even if the cover assembly is curved or similar during operation, there is secure electrical contact between the sealing element and both the first terminal and the base plate. Since the surface-treated surface is not formed entirely on the contact surfaces of the base plate and / or the first terminal, the base plate and the first terminal can be at least partially exposed to warping or similar in these contact areas.the cover assembly and maintain electrical contact. This prevents corrosion at the cathode throughout the entire service life of the cover assembly.

[0009] The surface-treated first partial surface preferably comprises a plurality of discrete surface regions. The discrete surface regions can be, for example, circles or quadrilaterals or other geometric surfaces. The discrete surface regions preferably all lie in a common plane and are more preferably evenly distributed along an entire circumference of the contact surface in the through-opening and / or the contact surface on the first terminal. Alternatively, it is also possible for the untreated second partial surfaces to be provided as a plurality of discrete surface regions.

[0010] More preferably, the surface-treated first partial area comprises one or more rectangular or arcuate surface regions, for example, if the first terminal is cylindrical. The remaining surface regions at the first terminal and / or at the through-opening of the base plate are then untreated second partial areas. It should be noted that it is also possible for the surface-treated partial areas and the untreated partial areas to be provided in exactly the opposite direction.

[0011] Particularly preferably, the surface-treated first partial area extends completely around a circumference of the first terminal and / or the through-opening of the base plate. The surface-treated first partial area can thus be formed as a type of strip along the entire circumference.

[0012] Further preferably, an area size of the first surface-treated partial region is the same as an area size of the untreated second partial region.

[0013] The surface-treated partial areas are provided in such a way that they remain electrically conductive, so that the electrical contact between the first terminal and the base plate is made via the surface-treated first partial areas.

[0014] The surface-treated first partial surfaces are preferably produced by means of plasma activation and / or application of a primer and / or application of an adhesion promoter and / or performing a mechanical surface treatment, for example, roughening and / or pickling and / or etching. Of course, the electrical conductivity of the surface-treated first partial surface must be maintained.

[0015] Further preferably, the sealing element arranged between the first terminal and the base plate is a molded-on component. In particular, this allows for a simple, form-fitting adaptation of the sealing element to the terminal and / or the base plate.

[0016] More preferably, the sealing element is made of an elastomeric, electrically conductive material, in particular EPDM or FKM. Alternatively, the sealing element is an electrically conductive thermoplastic, in particular PPS or PP. More preferably, the cover assembly comprises a first and a second terminal. The sealing element at the first terminal is made of an electrically conductive material. The sealing element at the second terminal, which forms the anode, is made of an electrically non-conductive material.

[0017] The first and / or second terminal is preferably rectangular and, in particular, has a peripheral edge. The peripheral edge is preferably directed toward the inside of the battery cell.

[0018] The first terminal, which serves as the cathode, is preferably made of aluminum. The second terminal, which serves as the anode, is preferably made of an aluminum-copper composite. The base plate is more preferably made of aluminum.

[0019] Further preferably, the sealing element is formed in one piece and comprises, in particular, an outer region, a central region arranged in the through-opening, and an inner region. The outer region and the inner region are formed substantially parallel to the base plate and extend such that the outer region and the inner region enclose at least part of the base plate.

[0020] Further preferably, the surface-treated first partial surfaces of the first terminal and the surface-treated first partial surfaces of the base plate lie in one plane in the assembled state. This enables the shortest possible electrical connection between the first terminal and the base plate in the assembled state.

[0021] Furthermore, the present invention relates to a battery cell comprising a cover assembly according to the invention.

[0022] Preferred embodiments of the invention are described in detail below with reference to the accompanying drawings. In the drawing:

[0023] Fig. 1 is a schematic sectional view of a cover assembly according to a first embodiment of the invention,

[0024] Fig. 2 is a schematic, enlarged partial sectional view of a first terminal of the cover assembly of Fig. 1,

[0025] Fig. 3 is a further enlarged partial sectional view of the first terminal of the cover assembly of Fig. 1,

[0026] Fig. 4 is a schematic side view of the first terminal of the cover assembly of Fig. 1, Fig. 5 is a schematic partial sectional view of a base plate of the cover assembly of Fig. 1,

[0027] Fig. 6 is a schematic representation of a battery cell with a cover assembly according to the invention from Fig. 1, and

[0028] Fig. 7 is a schematic representation of a battery cell with a cover assembly according to a second embodiment of the invention.

[0029] A cover assembly 1 according to a first preferred embodiment of the invention will be described in detail below with reference to Figs. 1 to 6.

[0030] The cover assembly 1 comprises, as shown in Fig. 1, a metallic base plate 2. Two through openings 20 are formed in the metallic base plate 2.

[0031] The cover assembly 1 further comprises a first terminal (cathode) 3 and a second terminal (anode) 4. One terminal each is arranged in one of the through openings 20 in the base plate 2.

[0032] The first terminal 3, which forms the cathode, is made entirely of aluminum. The second terminal 4, which forms the anode, is made of a first part 4a made of aluminum and a second part 4b made of copper.

[0033] The first and second terminals have the same geometric structure and are rectangular in shape (see Fig. 6).

[0034] The cover assembly 1 further comprises a first sealing element 5, which fixes the first terminal 3 to the base plate 2. The first sealing element 5 is made of an electrically conductive material. The first sealing element 5 comprises an outer region 50, a central region 51, and an inner region 52. The outer region 50 is directed toward the outside of the cover assembly. The inner region 52 is arranged on an inner side of the cover assembly 1.

[0035] As can be seen from Fig. 1 and 2, the sealing element is designed in a C-shaped section by two legs which are formed by the outer region 50 and the inner region 52 and the central region 51 connecting the outer region 50 and the inner region 52.

[0036] The first terminal 3, as further shown in Fig. 1, has a main area and a peripheral edge area 30, which is arranged on the inside of the cover assembly 1 and runs completely around the main area of ​​the first terminal 3. The corners of the first terminal, which is square, are rounded. This ensures a secure connection between the sealing element 5 and the first terminal 3.

[0037] The first sealing element 5 can be molded onto the first terminal 3 and the base plate 2 by an injection molding process, which can be inserted, for example, as inserts into an injection mold. Similarly, the second sealing element 5' on the second terminal 4 is molded onto the second terminal 4 and the base plate 2.

[0038] The sealing elements 5, 5' on the first terminal 3 and the second terminal 4 are each geometrically identical. The sealing elements 5, 5' are arranged in the through-openings 20 and are configured to seal a first connection area 6 between the terminal and the sealing element and a second connection area 7 between the base plate and the sealing element, providing a connection between the terminals and the base plate as well as a secure fixation.

[0039] The sealing element 5 on the first terminal 3 is made of an electrically conductive material. This provides corrosion protection for the first terminal 3, which serves as a cathode, since an electrical connection is established between the first terminal 3 and the base plate 2 via the electrically conductive sealing element 5.

[0040] In order to ensure the electrical connection between the first terminal 3 and the base plate 2 in all operating situations at the cathode, surface-treated first partial surfaces and untreated second partial surfaces are formed on the first terminal 3 and on the through-opening 20 in the base plate 2 in which the first terminal 3 is arranged.

[0041] Fig. 4 shows a side view of the first terminal 3. Here, a first contact surface 31 on the first terminal 3, which faces the sealing element 5, has surface-treated first partial surfaces 11. The surface-treated first partial surfaces 11 are formed as discrete surfaces with a circular geometry. All surface-treated first partial surfaces 11 lie in a common plane E1. The contact surface 31 on the first terminal 3 further has an untreated second partial surface 12. The second partial surface 12 surrounds the plurality of first partial surfaces 11, as can be seen from Fig. 4.

[0042] The first terminal 3 thus has a first contact surface 31 with the sealing element 5 on an outer peripheral surface. The base plate 2 has a second contact surface 21 with the sealing element 5 in the through-opening 20. The first contact surface 31 is shown in detail in Fig. 4, and the second contact surface 21 is shown in detail in Fig. 5.

[0043] Fig. 5 shows a section through the through-opening 20 in which the first terminal 3 is arranged. Here, the second contact surface 21 in the through-opening 20 has surface-treated first partial surfaces 13, which are also formed as discrete surfaces. Furthermore, the contact surface 21 of the through-opening 20 has untreated second partial surfaces 14. The surface-treated first partial surfaces 13 are also arranged in a common plane E2.

[0044] In the assembled state, the first plane E1 lies in the second plane E2 or deviates minimally from it, in particular by a maximum of 2 mm. This ensures that the surface-treated first partial surfaces 11 on the first terminal 3 and the surface-treated first partial surfaces 13 on the base plate 2 are at the same height in the through-opening and form a pressure-activated zone.

[0045] This ensures that, in the event of curvatures of the cover assembly 1, there is always contact between the surface-treated first partial surfaces 11 on the first terminal 3 and the sealing element 5 and between the sealing element 5 and the surface-treated first partial surfaces 13 in the through-opening 20.

[0046] The sealing element 5 on the first terminal 3 is made of an electrically conductive material. The sealing element 5 can be made of an electrically conductive elastomer or an electrically conductive thermoplastic.

[0047] Thus, in all operating states, a secure electrical contact of the first terminal 3 via the surface-treated first partial surfaces 11 to the sealing element 5 and from the sealing element 5 via the surface-treated first partial surfaces 13 at the through opening 20 can be achieved.

[0048] The surface-treated first partial surfaces 11, 13 can be produced by various methods, whereby it must be noted that the surface-treated first partial surfaces 11, 13 are always electrically conductive. For example, the surface-treated first partial surfaces 11, 13 can be produced by plasma activation or by applying a primer or an adhesion promoter, or by mechanical surface treatment.

[0049] The interruption of the surface-treated first partial surfaces 11, 13 at the first terminal 3 and at the through-opening 20 ensures that, in the event of twisting of the cover assembly, the sealing element 5 can follow such twisting to a certain extent without losing its sealing property and without losing its electrical contact to the first terminal 3 and to the base plate 2.

[0050] Thus, the cover assembly according to the invention can always ensure electrical contact with the first terminal 3, which is designed as a cathode, both at cold and at warm temperatures, so that corrosion at the first terminal 3 can be avoided.

[0051] The sealing element 5' on the second terminal 4 is made of an electrically non-conductive material. The electrically non-conductive material can be an elastomer or a thermoplastic. The second terminal 4 also has a peripheral edge region 40.

[0052] The cover assembly can thus be manufactured, for example, by two injection molding processes carried out in one injection mold, wherein in a first step the sealing element 5 is molded onto the first terminal 3 and in a second step the sealing element 5' made of a different material is molded onto the second terminal 4.

[0053] The C-shaped design of the sealing element 5 results in a relatively long first connection area 6, which provides media tightness between the sealing element 5 and the first terminal 3. A relatively long second connection area 7 also results between the sealing element 5 and the base plate 2.

[0054] In addition to sealing the first terminal 3 or the base plate 2, the sealing element 5 also serves as a fixing device for fixing the first terminal 3 in the through-opening 20 of the base plate 2. In particular, by designing the first terminal 3 with the circumferential edge region 30 and a step 22 on the base plate 2, which lies at least partially over the circumferential edge region 30, a positive, secure fixing of the first terminal 3 can be realized.

[0055] A filling opening 8 and a bursting area 9 are also provided in the base plate 2.

[0056] Furthermore, an insulation plate 10 is provided on the inside of the base plate 2, which can be clipped to the base plate 2 before or after the injection process of the sealing elements 5. The insulation plate 10 has a circumferential edge 10a in the area of ​​the through-openings 20, which ensures correct positioning during the injection process of the injected sealing element 5.

[0057] As can be further seen from Fig. 1, the two sealing elements 5, 5' are designed such that the inner region 52 partially encompasses the edge region 30, 40 of the two terminals 3, 4. This achieves an even better fixation of the terminals 3, 4 to the base plate 2.

[0058] Fig. 6 shows an assembled battery cell 100 in which the cover assembly 1 is fixed to a prismatic battery housing 101. The battery housing 101 is preferably made of the same material as the metallic base plate 2, in particular aluminum. This allows a simple connection between the cover assembly 1 and the battery housing 101, for example, by welding.

[0059] Thus, to ensure electrical conductivity between the cathode and the base plate 2, a pressure-activated zone can be provided in all operating situations, especially at different temperatures, so that an electrically conductive connection is present even when the components have different thermal expansion coefficients. Thus, even in the event of deformation, there are always areas between the sealing element 5 and the base plate 2, as well as the first terminal 3, in which a certain pressure is present between the components, so that at least one pressure-activated zone ensures electrical conductivity.

[0060] Fig. 7 shows an alternative embodiment of a battery cell 100, in which two cell covers 1a and 1b are provided, each arranged on opposite narrow sides of the battery cell 100 and covering the battery housing 101. The first terminal 3 is arranged on the first cell cover 1a, and the second terminal 4 is arranged on the second cell cover 1b. The second cell cover 1b additionally has the filling opening 8. The bursting area 9 is provided in the battery housing 101 on the long narrow side (see Fig. 7). The sealing elements in Fig. 7 are designed in the same way as in the first exemplary embodiment.

Claims

Claims 1. A cover assembly of a battery cell, comprising: a metallic base plate (2), a first terminal (3) designed as a cathode, which is arranged in a through-opening (20) of the base plate (2), and a sealing element (5) which fastens and seals the first terminal (3) to the base plate (2), wherein the sealing element (5) is made of an electrically conductive material, wherein the sealing element (5) is arranged in the through-opening (20) and is configured to seal a first connection region (6) between the first terminal (3) and the sealing element (5) and a second connection region (7) between the base plate (2) and the sealing element (5) and to provide a connection between the first terminal (3) and the base plate (2),and wherein a surface-treated first partial surface (13) and an untreated second partial surface (14) are provided on a first contact surface (31) of the first terminal (3) to the sealing element (5) and / or a surface-treated first partial surface (11) and an untreated second untreated partial surface (12) are provided on a second contact surface (21) in the through-opening (20) of the base plate to the sealing element (5) in such a way that a force-fitting connection is formed between the base plate (2) and the sealing element (5) and between the first terminal (3) and the sealing element (5).

2. Cover assembly according to claim 1, wherein the surface-treated first partial surface (11, 13) comprises a plurality of discrete surface areas.

3. Cover assembly according to claim 2, wherein the discrete surface areas are circular or square.

4. Cover assembly according to one of the preceding claims, wherein the surface-treated first partial surfaces (11, 13) are completely surrounded by untreated second partial surfaces (12, 14).

5. Cover assembly according to one of the preceding claims, wherein the sealing element (5) is made of an electrically conductive, elastomeric material, in particular EPDM or FKM.

6. Cover assembly according to one of the preceding claims, which comprises a first terminal (3) and a second terminal (4).

7. Cover assembly according to claim 6, wherein the first terminal (3) and the second terminal (4) are each rectangular and in particular have a circumferential edge region (30, 40).

8. Cover assembly according to one of claims 6 or 7, wherein the sealing element (5') on the second terminal (4) is made of an electrically non-conductive material.

9. Cover assembly according to one of the preceding claims, wherein in an assembled state of the first terminal (3) in the through-opening (2), the surface-treated first partial surfaces (11) of the first terminal (3) and the surface-treated first partial surfaces (13) of the base plate lie in a common plane.

10. Cover assembly according to one of the preceding claims, wherein the sealing element (5, 5') is formed in one piece.

11. Battery cell comprising a cover assembly (1) according to one of the preceding claims.

Images