A battery cell and a battery pack

Abstract

This utility model relates to the field of new energy battery technology and discloses a battery cell and a battery pack. The battery cell includes: a shell with multiple corners; a first insulating coating applied to each corner; and an insulating film fixedly connected to the shell and covering the outer surface of each corner. The first insulating coating is located between the shell and the insulating film, and the first insulating coating and the insulating film are stacked. The corners of the shell are stress concentration points of the battery cell. The first insulating coating and the insulating film are stacked at the corners, which can locally strengthen the corners, improve their insulation performance, and work together with the insulating film to provide good protection for the corners. This also reduces the coating area of ​​the insulating coating. Compared to coating the entire outer surface of the shell with an insulating coating, this reduces the cost of the battery cell. The insulating coating does not increase the size of the battery cell, ensuring the energy density of the assembled battery cell.

Description

Technical Field

[0001] This utility model relates to the field of new energy battery technology, and in particular to a battery cell and battery pack. Background Technology

[0002] Existing lithium-ion battery casings are typically made of aluminum. To improve their insulation performance, an insulating film is usually wrapped around the outside of the casing, providing insulation protection and improving the appearance of the lithium-ion battery. However, current industry-standard lithium-ion battery coating processes suffer from insufficient adhesion and insulation performance of the insulating film after coating, limiting the application scenarios and performance of lithium-ion batteries.

[0003] With the increasing demand for large-size lithium-ion batteries, the internal stress problem of lithium-ion batteries has become increasingly prominent. Conventional insulating film coating methods are prone to defects such as insufficient insulation performance, failing to provide adequate protection for lithium-ion batteries. Especially under certain special operating conditions, such as being subjected to compression or impact, stress concentration areas such as the corners of square lithium-ion batteries may cause the cell insulation layer to lose its protective function. Utility Model Content

[0004] The purpose of this invention is to provide a battery cell to solve the problem that the insulating film on the outside of lithium-ion batteries in the prior art cannot provide protection; this invention also provides a battery pack using this battery cell.

[0005] To achieve the above objectives, this utility model provides a battery cell, the battery cell comprising:

[0006] The outer casing has multiple corner sections;

[0007] A first insulating coating is applied to each of the corner portions;

[0008] An insulating film is fixedly connected to the outer shell and covers the outer surface of each corner portion. A first insulating coating is located between the outer shell and the insulating film, and the first insulating coating and the insulating film are stacked together.

[0009] In some embodiments, the housing includes a shell and a cover plate welded to the shell, the connection between the shell and the cover plate having a first weld, and the battery cell further includes a second insulating coating that covers the first weld.

[0010] In some embodiments, the weld width of the first weld is W1, and the coverage width of the second insulating coating is W2, satisfying: W2≥W1.

[0011] In some embodiments, the second insulating coating includes a first portion and a second portion, the first portion being coated on the housing and the second portion being coated on the cover plate, the first portion and the second portion being interconnected.

[0012] In some embodiments, the insulating film covers the second insulating coating.

[0013] In some embodiments, the cover plate is further provided with a liquid injection hole, and the cover plate is provided with a second weld at the wall of the liquid injection hole. The battery cell further includes a third insulating coating, which covers the second weld.

[0014] In some embodiments, the insulating film has a window, the housing has an exposed portion opposite the window, and the battery cell further includes a fourth insulating coating applied to the exposed portion.

[0015] In some embodiments, the fourth insulating coating is spaced apart from the insulating film, or a portion of the fourth insulating coating overlaps with the insulating film.

[0016] In some embodiments, the battery cell further includes an explosion-proof valve, which is disposed on the exposed portion and fixedly connected to the housing, and the fourth insulating coating has a clearance opening, with the explosion-proof valve disposed opposite to the clearance opening.

[0017] This utility model also provides a battery pack, including the battery cells described in any of the above technical solutions.

[0018] Compared with the prior art, the battery cell and battery pack of this utility model have the following advantages: When the battery cell is subjected to compression or collision, the stress concentration position of the battery cell at the corner of the outer shell is addressed by setting a first insulating coating at the corner. At the same time, the insulating film and the first insulating coating are stacked. The first insulating coating can locally strengthen the corner, improve the insulation performance of the corner, and work together with the insulating film to provide good protection for the corner. It also reduces the coating area of ​​the insulating coating. Compared with the outer surface of the outer shell being fully coated with an insulating coating, the cost of the battery cell can be reduced. Furthermore, after the battery cells are assembled into a group, the gaps formed between adjacent battery cells at the corners can be reasonably utilized by the insulating coating without increasing the size of the battery cells, thus ensuring the energy density of the assembled battery cells. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a single battery cell of this utility model;

[0020] Figure 2 yes Figure 1 A schematic diagram of the structure of a single battery cell after the fourth insulating coating has been applied from another perspective.

[0021] Figure 3 This is an enlarged schematic diagram of the corner of the battery cell of this utility model;

[0022] Figure 4 This is a schematic diagram of the assembly structure of the second and third insulating coatings of the battery cell of this utility model;

[0023] Figure 5 yes Figure 4 Enlarged cross-sectional view of a single battery cell at the first weld.

[0024] In the figure, 1. Outer shell, 11. Corner, 12. Shell, 13. Cover plate, 14. Injection hole, 15. Exposed part, 2. First insulating coating, 3. Insulating film, 31. Window, 4. First weld, 5. Second insulating coating, 51. First part, 52. Second part, 6. Second weld, 7. Third insulating coating, 8. Fourth insulating coating, 81. Refuge opening, 9. Explosion-proof valve. Detailed Implementation

[0025] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0026] A preferred embodiment of a battery cell of this utility model is as follows: Figures 1 to 5 As shown, the battery cell includes a shell 1, a first insulating coating 2, and an insulating film 3. The first insulating coating 2 and the insulating film 3 are both disposed on the shell 1 to improve the insulation of the battery cell.

[0027] The outer casing 1 has multiple corner portions 11, each corner portion 11 being chamfered, and the corners are stress concentration areas of the battery cell. In this embodiment, the battery cell is a square lithium battery, the outer casing 1 is square, and corner portions 11 are formed at each edge of the outer casing 1; in other embodiments, the battery cell may also be of other shapes, and the number of corner portions 11 may vary depending on the shape of the battery cell.

[0028] The first insulating coating 2 is applied to each corner 11. The insulating film 3 is fixedly connected to the outer shell 1 and covers the outer surface of each corner 11. The first insulating coating 2 is located between the outer shell 1 and the insulating film 3. The first insulating coating 2 and the insulating film 3 are stacked, that is, the insulating film 3 is located outside the first insulating coating 2 and covers the first insulating coating 2. The adhesion, insulation performance and structural strength of the insulating coating are stronger than those of the insulating film 3. The first insulating coating 2 is set between the corner 11 and the insulating film 3, which can locally strengthen the corner 11 and reduce the damage to the corner 11 caused by squeezing and collision during the use and production transportation of battery cells.

[0029] When the battery cell is subjected to compression or impact, the stress concentration point of the battery cell is located at the corner 11 of the outer casing 1. A first insulating coating 2 is provided at the corner 11, and an insulating film 3 is stacked on top of the first insulating coating 2. The first insulating coating 2 can locally strengthen the corner 11, improve the insulation performance of the corner 11, and work together with the insulating film 3 to provide good protection for the corner 11. It also reduces the coating area of ​​the insulating coating. Compared with the outer surface of the outer casing 1 being fully coated with an insulating coating, the cost of the battery cell can be reduced. Furthermore, after the battery cells are assembled into a group, the gaps formed between adjacent battery cells at the corner 11 can be reasonably utilized by the insulating coating without increasing the size of the battery cells, thus ensuring the energy density of the assembled battery cells.

[0030] In some embodiments, the housing 1 includes a housing 12 and a cover plate 13 welded to the housing 12, the connection between the housing 12 and the cover plate 13 having a first weld 4, and the battery cell also includes a second insulating coating 5, the second insulating coating 5 covering the first weld 4.

[0031] A second insulating coating 5 is applied to the first weld 4 at the connection between the housing 12 and the cover plate 13. The second insulating coating 5 can improve the strength of the first weld 4 and increase the corrosion resistance of the first weld 4. Compared with just covering the insulating film 3, its long-term durability is better.

[0032] In some embodiments, the weld width of the first weld 4 is W1, and the coverage width of the second insulating coating 5 is W2, satisfying: W2≥W1.

[0033] The coverage size W2 of the second insulating coating 5 is larger than the size W1 of the first weld 4, which can ensure that the second insulating coating 5 completely covers the first weld 4 and prevent parts of the first weld 4 from not being covered by the second insulating coating 5.

[0034] In some embodiments, the second insulating coating 5 includes a first portion 51 and a second portion 52, the first portion 51 being coated on the housing 12 and the second portion 52 being coated on the cover plate 13, and the first portion 51 and the second portion 52 being interconnected.

[0035] Normally, the first weld 4 is only located at the connection between the cover plate 13 and the housing 12. The first part 51 and the second part 52 of the second insulating coating 5 are respectively coated on the housing 12 and the cover plate 13. After the first part 51 and the second part 52 are connected, they can ensure that the first weld 4 is completely covered.

[0036] In some embodiments, the insulating film 3 is covered with the second insulating coating 5.

[0037] After the insulating film 3 covers the second insulating coating 5, the second insulating coating 5 and the insulating film 3 work together to increase the insulation and structural strength at the first weld 4. In this embodiment, the thickness of the portion of the insulating film 3 covered by the second insulating coating 5 is less than the thickness of the portion not covered by the second insulating coating 5, so that the sum of the thickness of the portion of the insulating film 3 covered by the second insulating coating 5 and the thickness of the second insulating coating 5 is equal to the thickness of the portion of the insulating film 3 not covered by the second insulating coating 5, thereby avoiding increasing the total thickness of the battery cell after the addition of the second insulating coating 5.

[0038] In some embodiments, the cover plate 13 is further provided with a liquid injection hole 14, and the cover plate 13 is provided with a second weld 6 at the hole wall of the liquid injection hole 14. The battery cell also includes a third insulating coating 7, which covers the second weld 6.

[0039] The cover plate 13 is usually welded to the wall of the injection hole 14 to form a second weld 6. The second weld 6 is covered with a third insulating coating 7, which can improve the strength of the second weld 6 and increase its corrosion resistance.

[0040] In some embodiments, the insulating film 3 has a window 31, the housing 1 has an exposed portion 15 opposite to the window 31, and the battery cell further includes a fourth insulating coating 8, which is applied to the exposed portion 15.

[0041] like Figure 2 As shown, a fourth insulating coating 8 is applied to the exposed portion 15 of the outer casing 1 opposite the window 31 of the insulating film 3. Compared to covering the exposed portion 15 with the insulating film 3, the fourth insulating coating 8 has greater bonding strength and better insulation performance. Increasing the thickness of the fourth insulating coating 8 can further improve the bonding strength. In this embodiment, the exposed portion 15 of the outer casing 1 can be specifically provided in part or all of the side, bottom, or top of the casing 12 to increase the bonding strength and insulation performance at different locations as needed. In some embodiments, when the exposed portion 15 of the outer casing 1 is located at the top, the fourth insulating coating 8 can replace the patch, and the fourth insulating coating 8 can be applied to any location on the outer casing 1 except for the pole and the explosion-proof valve 9.

[0042] In some embodiments, the fourth insulating coating 8 is spaced apart from the insulating film 3, or a portion of the fourth insulating coating 8 overlaps with the insulating film 3.

[0043] The fourth insulating coating 8 is spaced apart from the insulating film 3. This spacing facilitates equipment operation when covering the insulating film 3, while also preventing the total thickness of the fourth insulating coating 8 and the insulating film 3 from becoming too large and increasing the size of the battery cell. In this embodiment, the spacing between the fourth insulating coating 8 and the insulating film 3 ranges from 0.05mm to 10mm.

[0044] The fourth insulating coating 8 overlaps with the insulating film 3 in part, which can improve the insulation effect at the overlapping position. When the fourth insulating coating 8 and the insulating film 3 are overlapped, the size of the overlapping part ranges from 0.05mm to 10mm.

[0045] In some embodiments, the battery cell further includes an explosion-proof valve 9, which is disposed on the exposed portion 15 and fixedly connected to the housing 1. The fourth insulating coating 8 has a clearance opening 81, and the explosion-proof valve 9 is disposed opposite to the clearance opening 81.

[0046] The clearance 81 of the fourth insulating coating 8 is set opposite to the explosion-proof valve 9, which can prevent the fourth insulating coating 8 from affecting the explosion-proof valve 9 to burst, and ensure rapid pressure relief of the battery cell in the event of thermal runaway.

[0047] This utility model also provides an embodiment of a battery pack, including a battery cell. The specific structure of the battery cell is the same as that of the battery cell described in any of the above embodiments, and will not be repeated here.

[0048] In summary, this utility model embodiment provides a battery cell and a battery pack. When the battery cell is subjected to compression or impact, a first insulating coating is provided at the stress concentration location of the battery cell at the corner of the outer shell. Simultaneously, an insulating film and the first insulating coating are stacked. The first insulating coating can locally strengthen the corner, improve the insulation performance of the corner, and work together with the insulating film to provide good protection for the corner. It also reduces the coating area of ​​the insulating coating. Compared with coating the entire outer surface of the outer shell with an insulating coating, the cost of the battery cell can be reduced. Furthermore, after the battery cells are assembled into a group, the gaps formed between adjacent battery cells at the corners can be reasonably utilized by the insulating coating without increasing the size of the battery cells, thus ensuring the energy density of the assembled battery cells.

[0049] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A battery cell, characterized in that, The battery cell includes: The outer casing has multiple corner sections; A first insulating coating is applied to each of the corner portions; An insulating film is fixedly connected to the outer shell and covers the outer surface of each corner portion. A first insulating coating is located between the outer shell and the insulating film, and the first insulating coating and the insulating film are stacked together.

2. The battery cell according to claim 1, characterized in that, The outer casing includes a housing and a cover plate welded to the housing. The connection between the housing and the cover plate has a first weld. The battery cell also includes a second insulating coating that covers the first weld.

3. The battery cell according to claim 2, characterized in that, The weld width of the first weld is W1, and the coverage width of the second insulating coating is W2, satisfying the condition: W2≥W1.

4. The battery cell according to claim 3, characterized in that, The second insulating coating includes a first part and a second part, the first part being coated on the housing and the second part being coated on the cover plate, the first part and the second part being interconnected.

5. The battery cell according to claim 4, characterized in that, The insulating film covers the second insulating coating.

6. The battery cell according to claim 2, characterized in that, The cover plate is also provided with a liquid injection hole, and the cover plate is provided with a second weld at the hole wall of the liquid injection hole. The battery cell also includes a third insulating coating, which covers the second weld.

7. The battery cell according to any one of claims 1-6, characterized in that, The insulating film has a window, the housing has an exposed portion opposite to the window, and the battery cell further includes a fourth insulating coating applied to the exposed portion.

8. The battery cell according to claim 7, characterized in that, The fourth insulating coating is spaced apart from the insulating film, or a portion of the fourth insulating coating overlaps with the insulating film.

9. The battery cell according to claim 7, characterized in that, The battery cell also includes an explosion-proof valve, which is located on the exposed part and fixedly connected to the outer casing. The fourth insulating coating has a clearance opening, and the explosion-proof valve is arranged opposite to the clearance opening.

10. A battery pack, characterized in that, Includes the battery cell described in any one of claims 1-9.

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