Battery cap and lithium battery

Abstract

The utility model relates to the technical field of lithium batteries, and discloses a battery cap and a lithium battery, the battery cap comprises: a sealing ring, which is arranged opposite to a pole group along the axial direction; a first mounting space is defined by the peripheral wall of the inner side of the sealing ring, and an anti-explosion piece and a conduction piece are arranged in the first mounting space; the conduction sheet is arranged on one side, close to the pole group in the axial direction, of the explosion-proof sheet; the insulating ring is arranged around the circumferential flange of the conduction sheet; a first connecting part is formed on one side of the insulating ring along the axial direction, and the first connecting part is arranged between the conduction sheet and the explosion-proof sheet; and a second connecting part is formed on the other side of the insulating ring along the axial direction, is arranged between the conducting sheet and the pole group, and is suitable for being propped against the pole group, so that the sealing ring and the pole group are always kept in clearance fit. According to the battery cap provided by the utility model, the sealing ring bottom supporting table is prevented from being inserted into a pole group and damaging a pole piece after a battery cell is packaged.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, in particular to a battery cap and a lithium battery. Background Art

[0002] In the existing lithium battery cap, a bottom support is usually set at the lower end of the sealing ring. When the battery cell is abused, especially when overcharged, a large amount of gas will be generated inside the battery cell. When the internal gas pressure reaches the preset value, the current interrupt device (CID) connecting the explosion-proof plate and the conductive plate will flip to form a circuit break to ensure the safety of the battery cell; at this time, the bottom support supports the conductive plate to prevent the conductive plate from falling off and prevent the conductive plate from contacting the explosion-proof plate again to form a path. However, in actual production, it is found that the bottom support is very easy to insert into the pole group after the battery cell is packaged, which is easy to damage the pole piece.

[0003] In the prior art, as shown in the patent document with the announcement number CN213425149U, the isolation ring is eliminated and an insulating layer is provided on the connecting piece and / or the explosion-proof piece to isolate the explosion-proof piece from the connecting piece. The insulating layer is made of heat-resistant material to ensure its insulation effect in a high temperature environment. However, the cap of this structure cannot avoid the risk of the sealing ring bottom support inserting into the pole group. The bottom support is very easy to insert into the pole group after the battery cell is packaged, which is easy to damage the pole piece. Utility Model Content

[0004] In view of this, the utility model provides a battery cap and a lithium battery to solve the problem that the sealing ring bottom support of the existing lithium battery cap is easily inserted into the electrode group after the battery cell is packaged, which is easy to damage the electrode piece.

[0005] In a first aspect, the utility model provides a battery cap, comprising:

[0006] The sealing ring is arranged opposite to the pole group in the axial direction; the inner peripheral wall of the sealing ring encloses a first installation space, and the first installation space is provided with an explosion-proof plate and a conductive plate;

[0007] The conducting piece is arranged on one side of the explosion-proof piece close to the pole group along the axial direction;

[0008] An insulating ring is arranged around the circumferential flange of the conductive piece; a first connecting portion is formed on one side of the insulating ring along the axial direction, and the first connecting portion is arranged between the conductive piece and the explosion-proof piece; a second connecting portion is formed on the other side of the insulating ring along the axial direction, and the second connecting portion is arranged between the conductive piece and the pole group, and the second connecting portion is suitable for abutting against the pole group so that the sealing ring and the pole group always maintain a clearance fit.

[0009] Beneficial effects: The battery cap provided by the utility model is provided with an insulating ring, and a first connecting portion is formed on one side of the insulating ring along the axial direction. The first connecting portion is provided between the conductive piece and the explosion-proof piece, thereby insulating the conductive piece and the explosion-proof piece; a second connecting portion is formed on the other side of the insulating ring along the axial direction, and the second connecting portion is extended to between the conductive piece and the pole group so that the second connecting portion abuts against the pole group, thereby limiting the pole group through the second connecting portion, canceling the bottom support structure of the sealing ring before the improvement, and avoiding the sealing ring bottom support from being inserted into the pole group and damaging the pole piece after the battery cell is packaged.

[0010] In an optional embodiment, the conductive piece includes a first step portion and a second step portion, the first step portion is arranged opposite to the explosion-proof piece in the axial direction, and the second step portion is arranged on a side of the first step portion away from the explosion-proof piece;

[0011] A third connection portion is formed between the first connection portion and the second connection portion; the third connection portion and the first connection portion together enclose a second installation space, and the second installation space is suitable for limiting and fixing the first step portion; the third connection portion and the second connection portion together enclose a third installation space, and the third installation space is suitable for limiting and fixing the second step portion.

[0012] Beneficial effect: The first connecting part, the second connecting part and the third connecting part jointly surround the conducting piece, which not only helps to improve the insulation effect of the insulating ring on the conducting piece and the explosion-proof piece, but also limits and fixes the first step part through the second installation space and limits and fixes the second step part through the third installation space, thereby ensuring the firmness of the insulating ring fixing the conducting piece, effectively avoiding the conducting piece from flipping, shaking and falling off after the current cut-off mechanism is triggered, thereby avoiding the conducting piece and the explosion-proof piece from contacting again to form a passage.

[0013] In an optional embodiment, the second connection portion is formed by extending the inner peripheral wall of the third connection portion radially toward a central area close to the conductive sheet.

[0014] Beneficial effect: The sharp part of the second connection part is prevented from abutting against the pole group, thereby preventing the second connection part from being inserted into the pole group after the battery cell is packaged, and preventing the second connection part from damaging the pole piece.

[0015] In an optional implementation, the insulating ring includes an insulating body, and the insulating body is made of a high temperature resistant material.

[0016] Beneficial effect: To ensure that the insulating ring will not be deformed or even melted under the high temperature conditions inside the battery, thereby ensuring the firmness of the insulating ring fixing the conductive sheet.

[0017] In an optional embodiment, the insulating ring further includes an expansion tape, which is coated on the inner and outer side walls of the insulating body, and the expansion tape is suitable for expanding when contacting and / or soaking in the electrolyte.

[0018] Beneficial effect: By coating the inner and outer side walls of the insulating body with expansion tape, on the one hand, the sharp part of the second connecting portion can be better prevented from contacting the electrode group, thereby avoiding damage to the electrode group; on the other hand, when the internal abnormality of the battery occurs, after the expansion tape expands when contacting and / or soaking in the electrolyte, the second connecting portion can better limit the electrode group in the axial direction, thereby effectively preventing the battery cell from shaking when subjected to high-intensity impact and causing battery cell failure, and enabling the insulating ring to firmly clamp and fix the conductive piece when the current cut-off mechanism is disconnected, thereby ensuring that the explosion-proof piece and the conductive piece are completely insulated and isolated.

[0019] In an optional embodiment, the expansion tape is bonded to the electrode assembly.

[0020] Beneficial effect: It is conducive to better limiting the pole group, thereby effectively preventing the battery cell from shaking when subjected to high-intensity impact and causing the battery cell to fail.

[0021] In an optional embodiment, the expansion tape includes a substrate layer with a plurality of through holes provided thereon; the expansion tape also includes an expansion body embedded in the through holes, and the expansion body is suitable for expanding when in contact with an infiltrating electrolyte.

[0022] Beneficial effect: The expansion body expands when it contacts and / or soaks in the electrolyte. On the one hand, the second connecting portion can better limit the pole group along the axial direction, thereby effectively preventing the battery cell from shaking when subjected to high-intensity impact and causing battery cell failure. On the other hand, the insulating ring can firmly clamp and fix the conductive piece when the current cut-off mechanism is disconnected, thereby ensuring complete insulation isolation between the explosion-proof piece and the conductive piece.

[0023] In an optional embodiment, the substrate layer is made of a heat-conductive material, and the substrate layer is suitable for quickly conducting the internal heat of the battery to the outside of the battery when the battery core generates heat.

[0024] Beneficial effect: When the battery cell generates heat, the heat inside the battery is quickly transferred to the outside of the battery through the substrate layer, effectively improving the safety performance of the battery cell.

[0025] In an optional embodiment, the battery cap further includes an electrode cap, which is arranged on a side of the explosion-proof plate axially away from the conductive plate; the electrode cap includes a third step portion;

[0026] The explosion-proof plate includes a plate body and a bent portion formed by folding the plate body near the circumferential edge toward a direction away from the conductive plate. The bent portion and the plate body together enclose a fourth installation space, which is suitable for accommodating the third step portion. The bent portion is welded to the third step portion.

[0027] Beneficial effect: It is helpful to enhance the stability of the connection between the explosion-proof disk and the electrode cap.

[0028] In a second aspect, the utility model further provides a lithium battery, comprising: a battery body, and the battery cap as described above.

[0029] Beneficial effects: The lithium battery of the second aspect includes the battery cap of the first aspect, and therefore, the lithium battery of the second aspect includes all the beneficial effects of the battery cap of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 It is an assembly diagram of a battery cap according to an embodiment of the utility model;

[0032] Figure 2 for Figure 1 A cross-sectional view of the conductive sheet shown in ;

[0033] Figure 3 for Figure 1 A cross-sectional view of the insulating ring shown in ;

[0034] Figure 4 for Figure 3 A local enlarged schematic diagram of the middle A;

[0035] Figure 5 for Figure 4 Schematic diagram of the structure of the medium expansion tape;

[0036] Figure 6 for Figure 1 A cross-sectional view of the bursting disk shown in FIG.

[0037] Description of reference numerals:

[0038] 10. sealing ring; 101. first installation space;

[0039] 20. Pole group;

[0040] 30. explosion-proof disk; 301. disk body; 302. bending portion; 303. fourth installation space;

[0041] 40, conductive sheet; 401, first step portion; 402, second step portion;

[0042] 50, insulating ring; 501, first connecting part; 502, second connecting part; 503, third connecting part; 504, second installation space; 505, third installation space; 506, avoidance gap; 51, insulating body; 52, expansion tape; 521, substrate layer; 5211, through hole; 522, expansion body;

[0043] 60. electrode cap; 601. third step portion;

[0044] 70. Current cut-off mechanism. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0046] Combine the following Figures 1 to 6 , describing an embodiment of the utility model.

[0047] According to an embodiment of the present utility model, on the one hand, a battery cap is provided, comprising:

[0048] Sealing ring 10, see Figure 1 As shown, the sealing ring 10 and the pole group 20 are arranged opposite to each other in the axial direction; the inner peripheral wall of the sealing ring 10 encloses a first installation space 101, and the explosion-proof piece 30 and the conductive piece 40 are arranged in the first installation space 101;

[0049] The conducting sheet 40 is arranged on one side of the explosion-proof sheet 30 close to the pole group 20 along the axial direction;

[0050] The insulating ring 50 is arranged around the circumferential flange of the conductive piece 40; the insulating ring 50 is made of an insulating material, and a first connecting portion 501 is formed on one side of the insulating ring 50 along the axial direction, and the first connecting portion 501 is arranged between the conductive piece 40 and the explosion-proof piece 30; the insulating ring 50 forms a second connecting portion 502 on the other side of the insulating ring 50 along the axial direction, and the second connecting portion 502 is arranged between the conductive piece 40 and the pole group 20, and the second connecting portion 502 is suitable for abutting against the pole group 20, so that the sealing ring 10 and the pole group 20 always maintain a clearance fit.

[0051] The battery cap provided by the utility model is provided with an insulating ring 50, and a first connecting portion 501 is formed on one side of the insulating ring 50 along the axial direction. The first connecting portion 501 is provided between the conductive piece 40 and the explosion-proof piece 30, thereby insulating the conductive piece 40 and the explosion-proof piece 30; a second connecting portion 502 is formed on the other side of the insulating ring 50 along the axial direction, and the second connecting portion 502 is extended to between the conductive piece 40 and the pole group 20 so that the second connecting portion 502 abuts against the pole group 20, thereby limiting the pole group 20 through the second connecting portion 502, canceling the bottom support structure of the sealing ring before the improvement, and avoiding the sealing ring bottom support from being inserted into the pole group and damaging the pole piece after the battery cell is packaged.

[0052] For further information, see Figure 1 As shown, the second connecting portion 502 abuts against the pole group 20, so that an avoidance gap 506 is formed between the side of the sealing ring 10 axially close to the pole group 20 and the pole group 20, thereby eliminating the bottom support of the sealing ring and preventing the bottom support from damaging the pole piece.

[0053] In some embodiments, please combine Figure 1 and Figure 2 As shown, the conductive piece 40 includes a first step portion 401 and a second step portion 402. The first step portion 401 is arranged opposite to the explosion-proof piece 30 in the axial direction, and the second step portion 402 is arranged on a side of the first step portion 401 away from the explosion-proof piece 30.

[0054] Please combine Figure 1 and Figure 3 As shown, a third connection portion 503 is formed between the first connection portion 501 and the second connection portion 502; the third connection portion 503 and the first connection portion 501 together enclose a second installation space 504, and the second installation space 504 is suitable for limiting and fixing the first step portion 401; the third connection portion 503 and the second connection portion 502 together enclose a third installation space 505, and the third installation space 505 is suitable for limiting and fixing the second step portion 402.

[0055] Furthermore, the third connection portion 503 is an integrally formed structure with the first connection portion 501 and the second connection portion 502 .

[0056] In this embodiment, the first connecting portion 501, the second connecting portion 502 and the third connecting portion 503 jointly surround the conducting piece 40, which is not only conducive to improving the insulation effect between the conducting piece 40 and the explosion-proof piece 30 by the insulating ring 50, but also the first step portion 401 is limited and fixed by the second installation space 504 and the second step portion 402 is limited and fixed by the third installation space 505, thereby ensuring the firmness of the insulating ring 50 fixing the conducting piece 40, effectively avoiding the conducting piece 40 from flipping, shaking and falling off after the current cut-off mechanism 70 is triggered, thereby avoiding the conducting piece 40 from contacting with the explosion-proof piece 30 again to form a passage.

[0057] Please note that, see Figure 1 As shown, Figure 1 The structure of the current cut-off mechanism 70 is shown in the figure. The area of ​​the explosion-proof plate 30 close to the central axis protrudes axially toward the conductive plate 40. The protruding part is connected to the conductive plate 40 by laser spot welding to form the current cut-off mechanism 70. The working principle of the current cut-off mechanism 70 is not repeated here.

[0058] In some embodiments, see Figure 1 As shown, the second connection part 502 is formed by the inner peripheral wall of the third connection part 503 extending radially toward the central area close to the conductive sheet 40 to avoid the sharp part of the second connection part 502 from abutting against the pole group 20, thereby avoiding the second connection part 502 from being inserted into the pole group 20 after the battery cell is packaged, and preventing the second connection part 502 from damaging the pole piece.

[0059] In some embodiments, see Figure 4 As shown, the insulating ring 50 includes an insulating body 51, which is made of a high temperature resistant material with a higher melting point to ensure that the insulating ring 50 will not deform or even melt under high temperature conditions inside the battery, thereby ensuring that the insulating ring 50 is firmly fixed to the conductive sheet 40.

[0060] Furthermore, the insulating body 51 may be made of a polyimide material with a high melting point.

[0061] In some embodiments, see Figure 4 As shown, the insulating ring 50 further includes an expansion tape 52 , which is coated on both inner and outer side walls of the insulating body 51 , and the expansion tape 52 is suitable for expanding when contacting and / or soaking in electrolyte.

[0062] In this embodiment, by coating the expansion tape 52 on the inner and outer side walls of the insulating body 51, on the one hand, the sharp part of the second connecting portion 502 can be better prevented from contacting the electrode group 20, thereby avoiding damage to the electrode group 20; on the other hand, when the internal part of the battery is abnormal, after the expansion tape 52 expands when contacting and / or soaking in the electrolyte, the second connecting portion 502 can better limit the electrode group 20 along the axial direction, thereby effectively avoiding the battery cell from shaking when subjected to high-intensity impact and causing the battery cell to fail, and the insulating ring 50 can firmly clamp and fix the conductive sheet 40 when the current cut-off mechanism 70 is disconnected, thereby ensuring that the explosion-proof sheet 30 and the conductive sheet 40 are completely insulated and isolated.

[0063] In some embodiments, the expansion tape 52 is bonded to the electrode group 20 , which is beneficial to better limit the electrode group 20 , thereby effectively preventing the battery cell from shaking when subjected to high-intensity impact and causing the battery cell to fail.

[0064] In some embodiments, see Figure 5 As shown, the expansion tape 52 includes a substrate layer 521 on which a plurality of through holes 5211 are provided; the expansion tape 52 also includes an expansion body 522 embedded in the through holes 5211, and the expansion body 522 is suitable for expanding when in contact with the electrolyte.

[0065] Furthermore, the expansion body 522 may be made of any one of cast polypropylene (CPP), oriented polystyrene (OPS), thermoplastic polyurethanes (TPU), polylactic acid (PLA) and polyolefin (PO).

[0066] In this embodiment, the expansion body 522 expands when it contacts and / or soaks in the electrolyte. On the one hand, the second connecting portion 502 can better limit the electrode group 20 along the axial direction, thereby effectively preventing the battery cell from shaking when subjected to high-intensity impact and causing battery cell failure. On the other hand, the insulating ring 50 can firmly clamp and fix the conductive piece 40 when the current cut-off mechanism 70 is disconnected, thereby ensuring that the explosion-proof piece 30 and the conductive piece 40 are completely insulated and isolated.

[0067] In some embodiments, the substrate layer 521 is made of a heat-conductive material, so that when the battery cell generates heat, the heat inside the battery is quickly transferred to the outside of the battery through the substrate layer 521, thereby effectively improving the safety performance of the battery cell.

[0068] Furthermore, the substrate layer 521 may be made of thermally conductive silicone material, which has good thermal conductivity.

[0069] In some embodiments, see Figure 1 As shown, the battery cap further includes an electrode cap 60, which is disposed on a side of the explosion-proof sheet 30 axially away from the conductive sheet 40; the electrode cap 60 includes a third step portion 601;

[0070] The explosion-proof plate 30 includes a plate body 301 and a bent portion 302 formed by folding the plate body 301 near the circumferential edge toward a direction away from the conductive plate 40. The bent portion 302 and the plate body 301 together enclose a fourth installation space 303 of a "U"-shaped structure. The fourth installation space 303 is suitable for accommodating a third step portion 601. The bent portion 302 and the third step portion 601 can be laser welded, which is beneficial to enhancing the stability of the connection between the explosion-proof plate 30 and the electrode cap 60.

[0071] According to an embodiment of the present invention, on the other hand, a lithium battery is provided, including: a battery body, and the battery cap as described above.

[0072] The lithium battery in this embodiment includes the above-mentioned battery cap, and therefore, the lithium battery in this embodiment includes all the beneficial effects of the above-mentioned battery cap.

[0073] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A battery cap, characterized in that: include: A sealing ring (10) is arranged axially opposite to the electrode group (20); the inner peripheral wall of the sealing ring (10) encloses a first installation space (101), and an explosion-proof plate (30) and a conductive plate (40) are arranged in the first installation space (101); The conductive sheet (40) is arranged on a side of the explosion-proof sheet (30) close to the pole group (20) along the axial direction; An insulating ring (50) is arranged around the circumferential flange of the conductive piece (40); the insulating ring (50) forms a first connecting portion (501) on one side along the axial direction, and the first connecting portion (501) is arranged between the conductive piece (40) and the explosion-proof piece (30); the insulating ring (50) forms a second connecting portion (502) on the other side along the axial direction, and the second connecting portion (502) is arranged between the conductive piece (40) and the pole group (20), and the second connecting portion (502) is suitable for abutting against the pole group (20), so that the sealing ring (10) and the pole group (20) always maintain a clearance fit.

2. The battery cap according to claim 1, characterized in that: The conductive piece (40) comprises a first step portion (401) and a second step portion (402), wherein the first step portion (401) is arranged opposite to the explosion-proof piece (30) in the axial direction, and the second step portion (402) is arranged on a side of the first step portion (401) away from the explosion-proof piece (30); A third connection portion (503) is formed between the first connection portion (501) and the second connection portion (502); the third connection portion (503) and the first connection portion (501) are jointly enclosed to form a second installation space (504), and the second installation space (504) is suitable for limiting and fixing the first step portion (401); the third connection portion (503) and the second connection portion (502) are jointly enclosed to form a third installation space (505), and the third installation space (505) is suitable for limiting and fixing the second step portion (402).

3. The battery cap according to claim 2, characterized in that: The second connection portion (502) is formed by extending the inner peripheral wall of the third connection portion (503) in a radial direction toward a central area close to the conductive sheet (40).

4. The battery cap according to claim 1, characterized in that: The insulating ring (50) comprises an insulating body (51), and the insulating body (51) is made of a high temperature resistant material.

5. The battery cap according to claim 4, characterized in that: The insulating ring (50) further comprises an expansion tape (52), wherein the expansion tape (52) is coated on the inner and outer side wall surfaces of the insulating body (51), and the expansion tape (52) is suitable for expanding when contacting and / or soaking in electrolyte.

6. The battery cap according to claim 5, characterized in that: The expansion tape (52) is bonded to the pole group (20).

7. The battery cap according to claim 5, characterized in that: The expansion tape (52) comprises a substrate layer (521), and a plurality of through holes (5211) are arranged on the substrate layer (521); the expansion tape (52) further comprises an expansion body (522), and the expansion body (522) is embedded in the through hole (5211), and the expansion body (522) is suitable for expanding when contacting with an electrolyte.

8. The battery cap according to claim 7, characterized in that: The substrate layer (521) is made of a heat-conducting material, and the substrate layer (521) is suitable for quickly conducting the internal heat of the battery to the outside of the battery when the battery core generates heat.

9. The battery cap according to any one of claims 1 to 8, characterized in that: The battery cap further comprises an electrode cap (60), wherein the electrode cap (60) is arranged on a side of the explosion-proof plate (30) axially away from the conductive plate (40); the electrode cap (60) comprises a third step portion (601); The explosion-proof plate (30) comprises a plate body (301) and a bent portion (302) formed by folding the plate body (301) close to the circumferential edge portion in a direction away from the conductive plate (40), wherein the bent portion (302) and the plate body (301) together enclose a fourth installation space (303), wherein the fourth installation space (303) is suitable for accommodating the third step portion (601), and the bent portion (302) is welded to the third step portion (601).

10. A lithium battery, characterized in that: include: A battery body, and a battery cap as claimed in any one of claims 1 to 9.

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