Cover assembly for a prismatic cell

Abstract

The invention relates to a cover assembly for a prismatic cell, comprising a terminal feedthrough and a base plate with at least one first functional opening. The terminal feedthrough is provided in the first functional opening, and the base plate has a reinforcing structure adjacently to the functional opening.

Description

[0001] Cover assembly for a prismatic cell

[0002] Description

[0003] The invention relates to a cover assembly for a prismatic cell.

[0004] The purpose of lid assemblies for prismatic cells is to close and seal the prismatic cell, protecting the cell chemistry from the environment. The lid assembly is specifically designed to prevent externally generated interfering substances, such as oxygen or water, from penetrating the prismatic cell. Another function of the lid assembly is to provide internal and external electrical contact between the prismatic cell and the cell. The prismatic cell can also be secured in a cell assembly via the lid assembly. External forces can act on the lid assembly, which supports the lid assembly.

[0005] It is an object of the invention to provide an improved cover assembly which is simple and cost-effective to manufacture.

[0006] This problem is solved by a cover assembly having the features of claim 1.

[0007] The cover assembly according to the invention with the features of claim 1 comprises a terminal feedthrough and a base plate with at least one first functional opening. The terminal feedthrough is arranged in the first functional opening. The base plate has a reinforcing structure adjacent to the first functional opening. Functional surfaces adjacent to the first functional opening of the cover assembly are subject to greater stress during production and operation than other areas of the cover assembly. The reinforcing structure enables a targeted improvement of the mechanical properties of the cover assembly. In particular, the reinforcing structure stiffens the base plate. This allows material to be saved at less stressed areas of the cover assembly, resulting in a lighter and more cost-effective cover assembly. The cover assembly preferably comprises two terminal feedthroughs, in particular an anode and a cathode.The terminal feedthrough enables electrical contact between the prismatic cell and the electrical energy storage device inside and electrical loads outside the prismatic cell. The base plate preferably extends over the entire surface of an opening in the prismatic cell.

[0008] The prismatic cell is preferably an accumulator or a supercapacitor.

[0009] The subclaims show preferred developments of the invention.

[0010] The lid assembly preferably comprises a burst zone, wherein the burst zone is arranged in a second functional opening of the base plate. The burst zone allows pressure and temperature activation in the event of cell failure, allowing the cell chemistry to exit the prismatic cell in a controlled manner. For this purpose, a defined mechanical and thermal weak point is preferably incorporated in the burst zone. The arrangement of a reinforcement structure around the burst zone prevents deformation in the event of cell failure, thereby ensuring reliable functioning of the burst zone.

[0011] The lid assembly further preferably comprises a filling opening, wherein the filling opening is arranged in a third functional opening of the base plate. Particularly preferably, the base plate has two filling openings. An electrolyte can be filled into the prismatic cell through the filling opening. A second filling opening facilitates the extraction of the gas displaced by the electrolyte, thereby accelerating the filling process. Preferably, the filling opening is designed to be closed by a plug. Particularly preferably, the plug is designed to be welded to the lid assembly after the cell has been filled. The reinforcing structure at the filling opening prevents mechanical deformation during the filling process, thereby reducing the risk of leakage.

[0012] The reinforcement structure is preferably arranged in a ring around the functional opening. This avoids weak points at the functional opening and ensures uniform mechanical properties of the functional opening.

[0013] More preferably, the reinforcing structure has an embossed portion. The embossed portion is, in particular, a bead, a nub, and / or a flat embossed portion. More preferably, the base plate is made from a semi-finished product with a uniform wall thickness, in particular a sheet metal component. Embossed portions can be produced easily and quickly through forming processes and enable a reliable improvement in the mechanical properties of the base plate. In particular, embossed portions improve the rigidity of the reinforcing structure.

[0014] The base plate particularly preferably has a regular structure, in particular a honeycomb structure or a lattice structure. The base plate preferably has a consistent thickness. Honeycomb or lattice structures, particularly as the core of a sandwich panel, exhibit high flexural rigidity and strength while being lightweight. Alternative regular structures are box, strut, or cross-strut structures. The regular structure enables cover assemblies with a flat base plate that exhibit high rigidity while being lightweight. The structures can protrude inward, outward, or in both directions.

[0015] According to a further preferred embodiment of the invention, the base plate has an irregular bionic structure. In this case, areas of a component subject to less stress are removed to save weight. The irregular bionic structure is preferably determined using computer-aided topology optimization.

[0016] The cover assembly preferably comprises a film attached to the base plate. The film can be attached to the inside and / or outside of the base plate. Preferably, the film is firmly bonded to the base plate. This allows the properties of the base plate to be improved while saving space.

[0017] The film is further preferably an electrical insulation layer and / or a gas permeation-reducing film and / or a part of the bursting area. As an electrical insulation layer, the film enables electrical insulation of the base plate in front of the terminal feedthrough, the housing, and / or components inside the prismatic cell. As a gas permeation-reducing film, the film prevents fluid exchange between the interior of the prismatic cell and the environment. Thus, the base plate can have permeable structures that are sealed by the gas permeation-reducing film. Furthermore, the film can form a defined weak point in the bursting area. In particular, the film is embossed in the bursting area so that the film has a defined failure point in the bursting area.

[0018] The base plate is preferably a plastic component, particularly made of an electrically insulating plastic. This allows the base plate to be manufactured cost-effectively. Furthermore, the plastic plate eliminates the need for an additional insulating component between the terminal feedthrough and the housing of the prismatic cell.

[0019] More preferably, the terminal feedthrough and / or the burst area and / or the filling opening are inserts. The integration of inserts into the base plate enables simple integration of additional functionalities. Furthermore, the integrated design of the cover assembly reduces its assembly effort. A further advantage of the inserts is the base plate's ability to compensate for tolerances in the terminal feedthrough, the burst area and / or the filling opening during production. According to a further preferred embodiment of the invention, the base plate is a metal component. In particular, the base plate is made from a sheet metal component. This enables a cost-effective and space-saving base plate with good mechanical properties. A preferred material is aluminum.

[0020] The cover assembly preferably comprises an electrical insulation layer arranged on the base plate. The insulation layer is designed to electrically insulate the base plate from the terminal feedthrough. The insulation layer is preferably firmly bonded to the base plate. The electrical insulation layer is preferably arranged between the terminal feedthrough and the base plate, in particular on the inside of the base plate. This enables reliable electrical insulation between the terminal feedthrough and the base plate.

[0021] More preferably, the electrical insulation layer is embodied as a coating and / or a film and / or as an overmolded electrical insulation layer. Thus, the electrical insulation layer can be manufactured cost-effectively and easily attached to the base plate. If the electrical insulation layer is a film, the film is preferably pre-embossed and adapted to the contour of the base plate.

[0022] Possible materials for the electrical insulation layer are thermoplastics such as PE, PP, PBT or PPS, but also elastomers such as EPDM or FKM.

[0023] Further details, advantages, and features of the present invention will become apparent from the following description of exemplary embodiments with reference to the drawings. It shows:

[0024] Fig. 1 is a schematic sectional view of a prismatic cell with a cover assembly according to a first embodiment,

[0025] Fig. 2 is a schematic plan view of a base plate of the cover assembly according to the first embodiment,

[0026] Fig. 3 is a schematic sectional view of a prismatic cell with a cover assembly according to a second embodiment,

[0027] Fig. 4 is a schematic perspective view of the base plate of the second embodiment, and

[0028] Fig. 5 is a schematic perspective view of a base plate of a cover assembly according to a third embodiment. A cover assembly 1 according to a first embodiment of the invention will be described in detail below with reference to Figures 1 and 2.

[0029] Figure 1 shows a sectional view through a longitudinal plane of a prismatic cell 3. The prismatic cell 3 comprises a housing 2, which is closed on an upper side by the cover assembly 1. An electrical energy storage device 4 is arranged within the housing 2.

[0030] The cover assembly 1 comprises a base plate 12 with three functional openings 41, 42, 43 and an electrical insulation layer 18, two terminal feedthroughs 21, and a bursting area 22. A terminal feedthrough 21 is arranged in each of the two first functional openings 41. The bursting area 22 is formed in a second functional opening 42.

[0031] The first functional opening 41 defines an opening in the base plate 12 of the cover assembly 1, in which the pole feedthrough 21 is arranged and around which a reinforcing structure 5 is attached.

[0032] The second functional opening 42 defines an opening in the base plate 12 of the lid assembly 1, in which the bursting area 22 is arranged and around which a reinforcing structure 5 is attached.

[0033] The electrical energy storage device 4 comprises at least one negative electrode 7 and one positive electrode 8, which are enclosed by an electrolyte 9. The electrical energy storage device 4 can be, for example, a lithium-ion battery, a sodium-ion battery, or a supercapacitor.

[0034] One pole bushing 21 is connected to the negative electrode 7 inside the prismatic cell 3 and forms an anode 25. The other pole bushing 21 is connected to the positive electrode 8 inside the prismatic cell 3 and forms a cathode 26.

[0035] The thin-walled base plate 12 in Figure 1 is made of a sheet metal material, wherein the base plate 12 is designed to be connected circumferentially to the housing 2 of the prismatic cell 3 by a welded joint 27.

[0036] The housing 2 preferably has a wall thickness of 0.3 - 1.0 mm and is preferably made of aluminum.

[0037] Reinforcing structures 5 are formed in the base plate 12 in a ring shape around the first and second functional openings 41, 42, which locally improve the mechanical properties of the base plate 12. The reinforcing structures 5 in Figure 1 are designed as embossed portions 15, which are preferably introduced into the base plate 12 by a forming process. Alternatively, the base plate 12 can also be cast or manufactured by an EDM process or 3D printing process.

[0038] Furthermore, the cover assembly 1 comprises an electrical insulation layer 18, which is glued as a film 23 flush with the underside of the base plate 12. Alternatively, an electrical insulation layer 18 can also be produced by rubberizing the underside of the base plate 12 or by applying a plastic coating.

[0039] The terminal feedthrough 21 is electrically insulated from the base plate 12 by the foil 23. For this purpose, the foil 23 is deep-drawn before being attached to the base plate 12, so that the foil 23 can be arranged radially between the terminal feedthrough 21 and the base plate 12 in the region of the first functional opening 41. The foil 23 preferably has a thickness of less than 2 mm.

[0040] The film 23 is also part of the bursting area 22. For this purpose, the film is locally weakened in the bursting area 22 so that it opens in the event of a cell failure under temperature and / or pressure activation.

[0041] Figure 2 shows a top view of the base plate 12 from Figure 1.

[0042] The two first functional openings 41 and the second functional opening 42 are arranged centrally along a longitudinal axis XX. The second functional opening 42 is arranged centrally and configured to accommodate the bursting area 22. The first functional openings 41, which are adjacent to a first end and a second end in the longitudinal direction R1, are configured to pass through the terminal feedthrough 21. The second functional opening 42 is larger than the two first functional openings 41.

[0043] For mechanical reinforcement of the base plate 12 around the first and second functional openings 41, 42, reinforcement structures 5 are arranged in a ring around the first and second functional openings 41, 42. The reinforcement structures 5 have different types of embossments 15.

[0044] All reinforcement structures 5 of the base plate 12 in Figure 2 have a combination of narrow beads 15a and flat embossments 15c. The reinforcement structures 5 at the first functional openings 41, in which the pole openings 21 are arranged, each additionally have four nubs 15b distributed around the circumference.

[0045] Thus, the first embodiment enables a cover assembly 1 with high mechanical strength combined with low weight and volume. Furthermore, the cover assembly 1 according to the first embodiment is quick and cost-effective to manufacture. Figure 3 shows another sectional view through a longitudinal plane of the prismatic cell 3 with the cover assembly 1 according to a second embodiment. The housing 2 and the electrical energy storage device 4 of the different embodiments in Figures 1 and 3 are similar.

[0046] The cover assembly 1 in Figure 3 has a metallic frame 11, which is attached to the housing 2 of the prismatic cell 3 by a welded joint 27. The base plate 12, made of an electrically insulating plastic, is arranged within the metallic frame 11. A positive connection is formed between the base plate 12 and the metallic frame 11.

[0047] The cover assembly 1 comprises two terminal feedthroughs 21, a filling opening 24, and a bursting area 22 with a first bursting area 22a and a second bursting area 22b. The two terminal feedthroughs 21, the filling opening 24, and the bursting area 22 are each arranged in a first, second, or third functional opening 41, 42, 43 of the base plate 12 and are designed as inserts 31, which are overmolded by the electrically insulating plastic of the base plate 12. The outer contour of the inserts 31 enables the formation of positive connections between the base plate 12 and the inserts 31.

[0048] The third functional opening 43 defines an opening in the base plate 12 of the lid assembly 1, in which the filling opening 24 is arranged and around which a reinforcing structure 5 is attached.

[0049] The base plate 12 according to the second embodiment has a reinforcing structure 5 around the first, second and third functional openings 41, 42, 43, in which more material is used.

[0050] The electrically insulating plastic of the base plate 12 may comprise a fire retardant or fillers for improved thermal conductivity.

[0051] Between the reinforcing structures 5, the base plate 12 in Figure 3 has a regular structure 17, which is designed as a honeycomb structure.

[0052] The terminal bushings 21 have an H-shaped cross-section, with the electrically insulating plastic of the base plate 12 flowing between the two parallel webs of the H-shaped cross-section to form a positive connection. Alternatively, the terminal bushing 21 can have other designs that enable a good positive connection with the base plate 12. The H-shaped cross-section is aligned coplanar with the base plate 12. An outer side of the H-shaped cross-section of the terminal bushing 21 is directed towards the interior of the prismatic cell 3. One terminal bushing 21 is connected to the negative electrode 7, thus forming the anode 25. Another terminal bushing 21 is connected to the positive electrode 8, thus forming the cathode 26. The other outer side of the H-shaped cross-section of the terminal bushing 21 is directed outwards and is designed to be contacted with an electrical conductor.

[0053] The terminal bushings 21 are arranged in the longitudinal direction R1 at two lateral ends near the metallic frame 11. The distance to the metallic frame 11 must be large enough to prevent voltage breakdown from the terminal bushing 21 to the housing.

[0054] The bursting area 22 is located centrally in the lid assembly 1. The bursting area 22 has a stepped structure, forming a first bursting area 22a and a second bursting area 22b. The first bursting area 22a has a smaller thickness than the second bursting area 22b. Thus, the compressive strength of the first bursting area 22a is lower than the compressive strength of the second bursting area 22b, so that in the event of cell failure, the first bursting area 22a opens first to relieve increasing pressure from the interior of the prismatic cell. The second bursting area 22b can then open if the pressure inside the prismatic cell continues to rise. The first bursting region 22a is arranged within the second bursting region 22b, wherein a notch is formed between the first bursting region 22a and the second bursting region 22b, which notch forms a defined failure point.A notch is also formed on the outer circumference of the second bursting area 22b, which forms a defined failure point for the second bursting area 22b.

[0055] The filling opening 24 is located in the base plate 12 between the bursting area 22 and the right-hand terminal feedthrough 21 in Figure 3. The filling opening 24 is used to introduce the electrolyte 9 into the prismatic cell 3 and to expel the gas displaced by the electrolyte 9. For this purpose, the filling opening 24 has a cylindrical through-hole, which is designed to be closed by a plug.

[0056] On an outer side of the base plate 12 of the cover assembly 1, which is oriented perpendicular to the transverse direction R2, a gas permeation-reducing film 23 is applied, which, when the prismatic cell 3 is filled, prevents gas exchange between the electrical energy storage device 4 and the environment outside the prismatic cell 3 and improves the mechanical properties of the base plate 12. Figure 4 shows a perspective view of the base plate 12 according to the second exemplary embodiment in the region of the first end in the longitudinal direction R1.

[0057] The base plate 12 is rectangular on its circumference and has a honeycomb-shaped regular structure 17. The hexagonal honeycombs of the regular structure 17 are open and oriented in the transverse direction R2.

[0058] The circular first functional openings 41 and second functional opening 42 are arranged within the regular structure 17. An annular reinforcement structure 5 is mounted around the first and second functional openings 41, 42, mechanically reinforcing the first and second functional openings 41, 42. The reinforcement structure 5 in the second embodiment is characterized by a solid construction.

[0059] Figure 5 shows a further perspective view of the base plate 12 according to a third embodiment. The third embodiment differs from the second embodiment in the shape of the regular structure 17.

[0060] The regular structure 17 in Figure 5 is a lattice structure. The lattice structure is preferably manufactured additively, but can also be cast.

[0061] In addition to the above written description of the invention, reference is hereby explicitly made to the graphic representation of the invention in the figures for its supplementary disclosure.

Claims

Patent claims 1. Cover assembly for a prismatic cell (3), comprising . a terminal bushing (21) and . a base plate (12) with at least one first functional opening (41), . wherein the pole bushing (21) is arranged in the first functional opening (41), and . wherein the base plate (12) has a reinforcing structure (5) adjacent to the first functional opening (41).

2. Lid assembly according to claim 1, comprising a burst area (22), wherein the burst area (22) is arranged in a second functional opening (42) of the base plate (12).

3. Lid assembly according to one of the preceding claims, comprising a filling opening (24), wherein the filling opening (24) is arranged in a third functional opening (43) of the base plate (12).

4. Cover assembly according to one of the preceding claims, wherein the reinforcing structure (5) is arranged in a ring shape around the first functional opening (41) and / or second functional opening (42) and / or third functional opening (43).

5. Cover assembly according to one of the preceding claims, wherein the reinforcing structure (5) has an embossed portion (15), in particular a bead (15a), and / or a knob (15b) and / or a flat embossed portion (15c).

6. Cover assembly according to one of the preceding claims, wherein the base plate (12) has a regular structure (17), in particular a honeycomb structure or a lattice structure.

7. Lid assembly according to one of the preceding claims, wherein the base plate (12) has an irregular bionic structure.

8. Cover assembly according to one of the preceding claims, comprising a film (23) which is attached to the base plate (12).

9. Lid assembly according to claim 8, wherein the film (23) is an electrical insulation layer (18) and / or wherein the film (23) is a gas permeation reducing film (23) and / or wherein the film (23) is part of the bursting area (22).

10. Cover assembly according to one of the preceding claims, wherein the base plate (12) is a plastic component.

11. Cover assembly according to claim 10, wherein the terminal feedthrough (12) and / or the bursting area (22) and / or the filling opening (24) is an insert (31).

12. Cover assembly according to one of claims 1 to 9, wherein the base plate (12) is a metal component.

13. Cover assembly according to claim 12, comprising an electrical insulation layer (18) which is arranged on the base plate (12), wherein the electrical insulation layer (18) is arranged to electrically insulate the base plate (12) from the pole feedthrough (21).

14. Cover assembly according to claim 13, wherein the electrical insulation layer (18) is designed as a coating and / or as a film (23) and / or as an injection-molded electrical insulation layer (18).

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