Cover for a battery cell, battery cell, battery module and motor vehicle

Abstract

The invention relates to a cover of a battery cell, comprising: a first cover part, a second cover part and a seal which is designed to electrically insulate the first cover part and the second cover part from one another; wherein the first cover part has an opening in which at least a part of the second cover part is arranged; the seal has a first, radially extending portion and an axially extending central portion; the first portion bears against a first main surface of the first cover part and the axially extending central portion bears against an inner wall of the opening; the first portion has a first material, and the seal is designed such that when a predefined heat input or temperature increase is exceeded within a predefined time, the first material changes in such a way that the first cover part is in direct contact with the second cover part and thus an electrically conductive connection is established between the first cover part and the second cover part.

Description

[0001] 24-0051

[0002] COVER FOR A BATTERY CELL, BATTERY CELL, BATTERY MODULE AND MOTOR VEHICLE

[0003] The present invention relates to a lid for a battery cell, a battery cell with the lid, a battery module with at least two of the battery cells and a motor vehicle, in particular an electric or hybrid vehicle, with a battery module.

[0004] Battery cells known from the prior art, in particular lithium-ion battery cells, for example for supplying electrical energy to a (electric) drive motor of a motor vehicle, in particular an electric or hybrid vehicle, typically have a housing with a housing base and a cover, wherein several of the battery cells are accommodated in a battery module and connected in parallel and / or in series to meet specified voltage and / or power requirements.

[0005] Figure 1 shows a portion of such a battery cell 100', and Figure 2 shows a complete battery cell 100'. The battery cell 100' comprises a housing 10 with a housing base 12, 13, which may have a housing middle section 12, in particular a cylindrical one, and a base 13, and a cover 11, 30, which has a first cover section 11. The first cover section 11 has an upper or outer main surface 16 and a lower or inner main surface 17 facing away from it. An opening 14, in particular a central one, for example cylindrical, is provided in the first cover section 11, which has an inner wall 15. The first cover section 11 can be integral or integral with the housing middle section 12 and, in some embodiments, integral or integral with the base 13, for example by using a deep-drawing process.

[0006] With reference to Fig. 2, the housing base body 12, 13 is fluid-tightly connected to the cover 11, 30, wherein the housing base body 12, 13 and the cover 11, 30 define an interior space of the battery cell 100 in which an electrode arrangement 180, in particular an electrode stack or an electrode winding, with a first electrode, a second electrode and a separator arranged between them, is arranged. 24-0051

[0007] The cover 11, 30 has a second cover part 30, wherein at least a section of a (central) part of the second cover part 30 is arranged in the opening 14, and a seal 20 which is arranged between the first and the second cover part 11, 30, and is configured to electrically insulate the first cover part 11 and the second cover part 30 from each other and to seal a gap between the first and the second cover part 11, 30.

[0008] The seal 20, which is in particular donut-shaped or ring-shaped, has a first radially (outwardly) extending perforated disc-like section 21, an axially, i.e. parallel to a longitudinal axis of the (cylindrical) housing middle part 12, extending cylindrical middle section 22 and a second radially (outwardly) extending perforated disc-like section 23.

[0009] In this arrangement, one axial end of the central section 22 is connected to the first section 21 and the other axial end of the central section 22 to the second section 23. The first section 21 rests against the first main surface 16 of the first cover part 11, the axially extending central section 22 rests against the inner wall 14 of the opening 14, and the second section 23 rests against the second main surface 17 of the first cover part 11.

[0010] The second, electrically conductive cover part 30 has a disc-shaped first section 31, a fully cylindrical second section 32, and a disc-shaped third section 33, which are connected to each other. The first section 31 rests against a surface of the first section 21 of the seal 20 facing away from the first main surface 16 of the first cover part 11, an outer surface of the second section 32 rests against an inner surface of the central section 22 of the seal 20, and the third section 33 rests against a surface of the second section 23 of the seal 20 facing away from the second main surface 17 of the first cover part 11.

[0011] In the event of a defect, particularly a thermal runaway of the battery cell 100', the battery cell 100' can heat up to such an extent that the seal 20 is damaged by the heat input and / or at least partially melts, thereby creating an electrically conductive connection between the first cover part 11 and the second cover part 30 or a positive terminal of the 24-0051

[0012] Battery cell 100', which is formed by the first section 31 of the second cover part 30, is electrically connected to a negative terminal of battery cell 100', which is formed by a section of the base 13, via the electrically conductive housing middle part 12.

[0013] This can cause a current path to close within the parallel connection of several 100' battery cells if they are connected in parallel. The resulting short-circuit currents can cause any neighboring 100' battery cells to also thermally fail.

[0014] To isolate these short circuits, various isolation concepts are conceivable, for example, using fuses. These fuses are typically located within the battery cell 100' itself or are situated in a cell contacting system for connecting the individual battery cells 100'. However, the short-circuit currents can be within the typical operating current range of the battery cell 100', so that fuse design is subject to an irresolvable conflict of objectives.

[0015] One of the objectives of the present invention is to improve a battery cell.

[0016] This problem is solved by the features of the independent patent claims. Further preferred embodiments of the invention are the subject of the dependent patent claims.

[0017] According to a first aspect of the present invention, a cover for a battery cell, in some embodiments of a battery cell, has:

[0018] a first cover part, in some embodiments electrically conductive, a second cover part, in some embodiments electrically conductive, and a seal designed to electrically insulate the first cover part and the second cover part from each other and, in some embodiments, to seal a gap between the first and second cover parts; wherein

[0019] the first lid part has an opening, in some versions central, for example cylindrical, in which at least part of the second lid part is arranged;24-0051

[0020] the seal has a first, radially (outwardly) extending section and an axially extending middle section;

[0021] the first section of the seal rests against a first main surface of the first cover part and the axially extending central section of the seal rests against an inner wall of the opening;

[0022] the first section of the seal has a first material, and

[0023] The seal is designed such that, if a predetermined heat input or temperature increase is exceeded within a predetermined time, the first material changes in such a way that the first cover part is in direct contact with the second cover part, thereby creating an electrically conductive connection between the first cover part and the second cover part.

[0024] In some embodiments, with a suitable choice of the first material, the use of the cover according to the invention in a battery cell of a battery module in which at least two battery cells are connected in parallel can cause a current path within the parallel connection to close in the event of a defect, in some embodiments thermal runaway, of at least one of the battery cells, such that a resulting short-circuit current causes a fuse of the battery cell or the battery module to be reliably triggered, thereby preventing any thermal runaway of neighboring battery cells and thus improving the functionality and safety of the battery module.

[0025] In some designs, this can significantly reduce the short-circuit resistance, resulting in significantly higher short-circuit currents in the battery module, which can lead to the fuse reliably tripping.

[0026] Such a battery cell can have a housing with a housing base, which in some designs may have a housing middle section (cylindrical in some versions) and a base, and a lid. 24-0051

[0027] The first lid part can be integral or one-piece with the housing middle part and, in some versions, integral or one-piece with the bottom, or manufactured, for example using a deep-drawing process.

[0028] In other embodiments, the first cover part may not be part of the housing base or may be a separate component of the housing. In this case, the first cover part can be connected to the housing middle part (fluid-tight) using known techniques.

[0029] The term "motor vehicle" used here refers in particular to a passenger car, including all types of motor vehicles, hybrid and battery-powered electric vehicles, as well as vehicles such as sedans, vans, buses, trucks, delivery vans and the like.

[0030] Any terms used herein, such as "comprises," "includes," "features," "has," "with," or any other variant thereof, are intended to cover non-exclusive inclusion. For example, a method or apparatus that includes or features a list of elements is not necessarily limited to those elements but may include other elements not expressly listed or inherent in such method or apparatus.

[0031] Furthermore, unless explicitly stated otherwise, "or" refers to an inclusive or and not an exclusive "or". For example, a condition A or B is satisfied by one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0032] The terms "ein" or "eine," as used here, are defined as "one or more." The terms "ein anderer" and "ein Weitere," as well as any other variant thereof, are to be understood as "at least one more."

[0033] The term "plural", as used here, means "two or more". 1 to understand. 24-0051

[0034] Preferred embodiments of the invention and their further developments are described below, each of which, unless expressly excluded, can be combined arbitrarily with each other as well as with the second aspect of the invention described below, the third aspect of the invention described below and the fourth aspect of the invention described below.

[0035] In some embodiments, the second cover part has a first section, in some embodiments disc-shaped, and a second section, in some embodiments fully cylindrical, which are connected to each other, wherein the first section of the second cover part abuts a surface of the first section of the seal facing away from the first main surface of the first cover part, and an outer lateral surface of the second section of the second cover part abuts an inner lateral surface of the central section of the seal.

[0036] In some designs, the seal has a second, radially extending section, wherein the second section of the seal abuts a second main surface of the first cover part; and the second section of the seal has a second material; and the first material is different from the second material.

[0037] In some embodiments, with a suitable choice of the first and second materials, the use of the cover according to the invention in a battery cell of a battery module in which at least two battery cells are connected in parallel can cause a current path within the parallel connection to close in the event of a defect, in some embodiments thermal runaway, of at least one of the battery cells in such a way that a resulting short-circuit current causes a fuse of the battery cell or the battery module to be reliably triggered, thereby preventing any thermal runaway of neighboring battery cells and thus improving the functionality and safety of the battery module.

[0038] In some versions, the second cover part has a third section, which in some versions is disc-shaped, wherein the second section of the second cover part and the third section of the second cover part are connected to each other. 24-0051

[0039] are, and the third section of the second lid part rests on a surface of the second section of the seal that faces away from the second main surface of the first lid part.

[0040] In some designs, the change in volume, or in some designs the change in thickness, of the first section of the seal as a function of a given temperature change differs from the change in volume, or in some designs the change in thickness, of the second section of the seal as a function of the given temperature change.

[0041] In some designs, the volume change of the first section of the seal, depending on the specified temperature change, is either a first volume increase or a first volume decrease.

[0042] In some designs, the volume change of the second section of the seal, depending on the specified temperature change, is a second volume increase or a second volume decrease.

[0043] In some designs, the volume change of the first section of the seal as a function of the specified temperature change is the first volume increase, while the volume change of the second section of the seal as a function of the specified temperature change is the second volume decrease, or

[0044] The first volume reduction is the change in volume of the first section of the seal as a function of the given temperature change, while the second volume increase is the change in volume of the second section of the seal as a function of the given temperature change.

[0045] In some designs, the first and second materials are selected such that, if a predetermined heat input or temperature rise is exceeded within a predetermined time, the first and second materials change in such a way that the first cover part is in direct contact with the second cover part, thereby establishing a direct electrically conductive connection between the first and second cover parts. 24-0051

[0046] In some designs, this can significantly reduce the short-circuit resistance, resulting in significantly higher short-circuit currents in the battery module, which can lead to the fuse reliably tripping.

[0047] In some designs, the thickness of the first section of the seal and / or the thickness of the second section of the seal is additionally selected such that, if the specified heat input or temperature increase is exceeded within the specified time, the thickness of the first section of the seal and / or the thickness of the second section of the seal changes in such a way that the first cover part is in direct contact with the second cover part, thereby establishing a direct electrically conductive connection between the first cover part and the second cover part.

[0048] A second aspect of the present invention relates to a battery cell which has a lid and a housing body as described above, wherein the housing body is fluid-tightly connected to the lid, and an interior space of the battery cell is defined by the housing body and the lid, in which an electrode arrangement, in some embodiments an electrode stack or electrode winding, is arranged with a first electrode, a second electrode and a separator arranged in between.

[0049] A third aspect of the present invention relates to a battery module comprising at least two of the battery cells described above, connected in parallel.

[0050] A fourth aspect of the present invention relates to a motor vehicle comprising a battery module as described above and an electric drive motor, wherein the at least two battery cells of the battery module are configured to supply the electric drive motor with electrical energy.

[0051] The features and advantages described in relation to the first aspect of the invention and its advantageous embodiment also apply, at least where technically appropriate, to the second aspect of the invention, the third aspect of the invention, and the fourth aspect of the invention and their advantageous embodiments, and vice versa. 24-0051

[0052] Further advantageous developments result from the following description of preferred embodiments. This is shown, in part schematically:

[0053] Fig. 1 shows a part of a battery cell known from the prior art,

[0054] Fig. 2 shows a battery cell known from the prior art,

[0055] Fig. 3 shows a battery cell according to one embodiment of the invention,

[0056] Fig. 4 shows a battery cell according to an embodiment of the invention after the application of heat,

[0057] Fig. 5 shows a battery cell according to another embodiment of the invention after the application of heat, and

[0058] Fig. 6 shows a motor vehicle according to one embodiment.

[0059] Fig. 3 schematically shows a battery cell 100 according to one embodiment of the invention. Like the battery cell 100' shown in Fig. 1, the battery cell 100 has a housing 10 with a housing base body 12, 13, which may have a housing middle part 12, in particular a cylindrical one, and a base 13, and a cover 11, 30, which has a first, electrically conductive cover part 11. The first cover part 11 has an upper or outer main surface 16 and a lower or inner main surface 17 facing away from it. The opening 14, shown in Fig. 1 and not separately labelled in Fig. 3, is provided in the first cover part 11 and has an inner wall 15, in particular a central opening, for example cylindrical.

[0060] The housing base 12, 13 is fluid-tightly connected to the cover 11, 30, wherein the housing base 12, 13 and the cover 11, 30 define an interior space of the battery cell 100 in which an electrode arrangement 180, in particular an electrode stack or an electrode winding, is arranged with a (not shown) first electrode, a (not shown) second electrode and a (not shown) separator arranged between them. 24-0051

[0061] The cover 11, 30 has a second, electrically conductive, cover part 30, wherein at least a section of a (central) part of the second cover part 30 is arranged in the opening 14, and a seal 40 which is arranged between the first and second cover part 11, 30, and is configured to electrically insulate the first cover part 11 and the second cover part 30 from each other and to seal a gap between the first and second cover part 11, 30.

[0062] The seal 40, which is in particular donut-shaped or ring-shaped, has a first radially (outwardly) extending perforated disc-like section 41 with a thickness du measured in the axial direction of the housing center part 12, i.e. parallel to a longitudinal axis of the (cylindrical) housing center part 12, a cylindrical center section 42 extending in the axial direction of the housing center part 12 and a second radially (outwardly) extending perforated disc-like section 43 with a thickness d2i measured in the axial direction of the housing center part 12.

[0063] In this arrangement, one axial end of the central section 42 of the seal 40 is connected to the first section 41, and the other axial end of the central section 42 is connected to the second section 43. The first section 41 rests against the first main surface 16 of the first cover part 11, the axially extending central section 42 rests against the inner wall 15 of the opening 14, and the second section 43 rests against the second main surface 17 of the first cover part 11.

[0064] The second cover part 30 has a disc-shaped first section 31, a fully cylindrical second section 32, and a disc-shaped third section 33, which are connected to one another. The first section 31 rests against a surface of the first section 41 of the seal 40 facing away from the first main surface 16 of the first cover part 11, an outer surface of the second section 32 rests against an inner surface of the central section 42 of the seal 40, and the third section 33 rests against a surface of the second section 43 of the seal 40 facing away from the second main surface 17 of the first cover part 11. 24-0051

[0065] Here, the first section 41 has a first material, while the second section 43 has a second material, the first material being different from the second material.

[0066] Furthermore, a change in volume, in particular a change in thickness, i.e., a change in the thickness du, of the first section 41 of the seal 40 as a function of a given temperature change is different from a change in volume, in particular a change in thickness, i.e., a change in the thickness d2i, of the second section 41 of the seal as a function of the given temperature change.

[0067] The volume change of the first section 41 of the seal 40 as a function of the specified temperature change is a first volume increase, in particular an increase in thickness du, or a first volume decrease, in particular a reduction in thickness du.

[0068] The volume change of the second section 43 of the seal 40 as a function of the specified temperature change is a second volume increase, in particular an increase in thickness d2i, or a second volume decrease, in particular a reduction in thickness d2i.

[0069] Fig. 4 shows an embodiment in which the volume change of the first section 41 of the seal 40 as a function of the predetermined temperature change is a first volume reduction, in this case a reduction of the thickness du of the first section 41 of the seal 40 illustrated in Fig. 3 to 0, and the volume change of the second section 43 of the seal 40 as a function of the predetermined temperature change is the second volume increase, i.e. an increase of the thickness d2i illustrated in Fig. 3 to that shown in Fig.

[0070] The thickness d22 of the second section 43 of the seal 40 is illustrated in Figure 4.

[0071] Fig. 5 shows another embodiment in which the volume change of the first section 41 of the seal 40 as a function of the predetermined temperature change is the first volume increase, i.e., an increase from the thickness du illustrated in Fig. 3 to the thickness di2 illustrated in Fig. 4 of the first section 41 of the seal 40, and the volume change of the second section 24-0051

[0072] 43 of the seal 40 depending on the specified temperature change the second volume reduction, in the present case a reduction of the thickness d2i of the second section 43 of the seal 40 illustrated in Fig. 3 to 0, is.

[0073] In the embodiments shown in Figs. 4 and 5, the first material and the second material are selected such that, if a predetermined heat input is exceeded within a predetermined time, the first material and / or the second material change in such a way that the first cover part is in direct contact with the second cover part, thereby creating an electrically conductive connection between the first cover part and the second cover part.

[0074] In addition, the thickness du of the first section 41 of the seal 40 and the thickness d2i of the second section 43 of the seal 40 are chosen such that, if the specified heat input is exceeded within the specified time, the thickness of the first section 41 of the seal 40 and / or the thickness of the second section 43 of the seal 40 changes in such a way that the first cover part 11 is in direct contact with the second cover part 30 and thereby the electrically conductive connection between the first cover part 11 and the second cover part 30 is established.

[0075] Fig. 6 shows a motor vehicle 300 according to one embodiment of the invention. The motor vehicle 300, in particular an electric or hybrid vehicle, has a battery module 200 according to the invention, which has at least two battery cells 100 as described above, connected in parallel, and an electric drive motor 301. The at least two battery cells 100 of the battery module 200 are configured to supply the electric drive motor 301 with electrical energy.

Claims

24-0051 REQUIREMENTS 1. Cover (11, 30) for a battery cell (100), comprising: a first lid part (11), a second lid part (30), and a seal (40) configured to electrically insulate the first lid part (11) and the second lid part (30) from each other; wherein the first lid part (11) has an opening (14) in which at least a part of the second lid part (30) is arranged; the seal (40) has a first radially extending section (41) and an axially extending central section (42); the first section (41) of the seal (40) abuts a first main surface (16) of the first cover part (11) and the axially extending central section (42) of the seal (40) abuts an inner wall (15) of the opening (14); the first section (41) of the seal (40) has a first material, and the seal (40) is arranged such that, if a predetermined heat input or temperature increase is exceeded within a predetermined time, the first material changes in such a way that the first cover part (11) is in direct contact with the second cover part (30) and thereby an electrically conductive connection is established between the first cover part (11) and the second cover part (30).

2. Lid (11, 30) according to claim 1, wherein the second lid part (30) has a first section (31), in particular a disc-shaped section, and a second section (32), in particular a solid cylindrical section, which are connected to each other, the first section (31) of the second lid part (30) bearing against a surface of the first section (41) of the seal (40) facing away from the first main surface (16) of the first lid part (11), and an outer lateral surface of the second section (32) of the second lid part (30) bearing against an inner lateral surface of the central section (42) of the seal (40). 24-0051 3. Lid (11, 30) according to claim 1 or 2, wherein the seal (40) has a second, radially extending section (43); the second section (43) of the seal (40) abuts a second main surface (17) of the first cover part (11); and the second section (43) of the seal (40) has a second material; and the first material is different from the second material.

4. Lid (11, 30) according to the preceding claim, wherein the second lid part (30) has a third section (33), in particular a disc-shaped section, wherein the second section (32) of the second lid part (30) and the third section (33) of the second lid part (30) are connected to each other, and the third section (33) of the second lid part (30) abuts a surface of the second section (43) of the seal (40) facing away from the second main surface (17) of the first lid part (11).

5. Lid (11, 30) according to any of the preceding claims and claim 3, wherein a change in volume, in particular a change in thickness, of the first section (41) of the seal (40) as a function of a predetermined temperature change is different from a change in volume, in particular a change in thickness, of the second section (41) of the seal (40) as a function of the predetermined temperature change.

6. Lid (11 , 30) according to claim 5, wherein the volume change of the first section (41) of the seal (40) depending on the predetermined temperature change is a first volume increase or a first volume decrease.

7. Lid (11, 30) according to claim 5 or 6, wherein the volume change of the second section (43) of the seal (40) depending on the predetermined temperature change is a second volume increase or a second volume decrease. 24-0051 8. Lid (11, 30) according to claim 7, wherein the volume change of the first section (41) of the seal (40) as a function of the predetermined temperature change is the first volume increase and the volume change of the second section (43) of the seal (40) as a function of the predetermined temperature change is the second volume decrease, or The volume change of the first section (41) of the seal (40) as a function of the specified temperature change is the first volume reduction, and the volume change of the second section (43) of the seal (40) as a function of the specified temperature change is the second volume increase.

9. Lid (11, 30) according to any of the preceding claims and claim 3, wherein the first material and the second material are selected such that, upon exceeding a predetermined heat input or temperature increase within a predetermined time, the first material and the second material change in such a way that the first lid part (11) is in direct contact with the second lid part (30) and thereby an electrically conductive connection is established between the first lid part (11) and the second lid part (30).

10. Lid (11, 30) according to the preceding claim, wherein additionally a thickness (du) of the first section (41) of the seal (40) and / or a thickness (d2i) of the second section (43) of the seal (40) are selected such that, when the predetermined heat input or temperature increase is exceeded within the predetermined time, the thickness of the first section (41) of the seal (40) and / or the thickness (d2i) of the second section (43) of the seal (40) are changed such that the first lid part (11) is in direct contact with the second lid part (30) and thereby the electrically conductive connection between the first lid part (11) and the second lid part (30) is established.

11. Battery cell (100) comprising a cover (11, 30) according to any of the preceding claims and a housing base body (12, 13), wherein the housing base body (12, 13) is fluid-tightly connected to the cover (11, 30), and an interior space of the battery cell (100) is defined by the housing base body (12, 13) and the cover (11, 30), in which an electrode arrangement (180),24-0051 in particular electrode stacks or electrode coils, comprising a first electrode, a second electrode and a separator arranged in between.

12. Battery module (200), comprising at least two battery cells (100) according to the preceding claim, which are connected in parallel.

13. Motor vehicle (300) comprising a battery module (200) according to the preceding claim and an electric drive motor (301), wherein the at least two battery cells (100) of the battery module (200) are configured to supply the electric drive motor (301) with electrical energy.

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