Battery cell and battery

Abstract

The utility model relates to a battery cell and a battery. The battery cell comprises at least one cell package, each core package comprises a positive pole lug, a negative pole lug, a negative pole piece and a positive pole piece, the positive pole lug is connected with the positive pole piece, the negative pole lug is connected with the negative pole piece, the positive pole lug extends in the direction away from the positive pole piece, the negative pole lug extends in the direction away from the negative pole piece, the length of the positive pole lug in the direction perpendicular to the extending direction of the positive pole lug is L1, and the length of the negative pole lug in the direction perpendicular to the extending direction of the positive pole lug is L2. The length of the negative tab in the direction perpendicular to the extension direction of the negative tab is L2, and L1 is greater than L2, so that the weldable area of the positive tab can be increased by increasing the length L1 of the positive tab, the over-current capability of the battery cell during fast charging can be improved, and the DCR of the battery cell is remarkably reduced.

Description

Technical Field

[0001] The present application relates to the field of electric energy technology, and in particular to a battery cell and a battery. Background Art

[0002] As the main power source for new energy vehicles, the speed of battery charging directly affects the user experience. Traditional charging methods generally take several hours to fully charge the battery, and the charging speed is slow, which limits the flexibility of users' travel. Fast charging technology can quickly complete charging in a short time by increasing the charging power, thereby improving the user experience. When the battery tabs of the related technology are welded to other components, the weldable area is small, which cannot meet the requirements of the battery's overcurrent capacity during fast charging, resulting in a high DC resistance (DCR) and a reduced cycle life of the battery cell. Utility Model Content

[0003] Based on this, a battery cell and a battery are provided, which can increase the weldable area of ​​the positive electrode ear, thereby improving the overcurrent capacity of the battery cell during fast charging and effectively reducing the DCR of the battery cell.

[0004] In a first aspect, the present application provides a battery cell, comprising at least one core package;

[0005] Each core package includes a positive electrode ear, a negative electrode ear, a negative electrode sheet and a positive electrode sheet, the positive electrode ear is connected to the positive electrode sheet, the negative electrode ear is connected to the negative electrode sheet, the positive electrode ear extends in a direction away from the positive electrode sheet, the negative electrode ear extends in a direction away from the negative electrode sheet, the length of the positive electrode ear perpendicular to its own extension direction is L1, the length of the negative electrode ear perpendicular to its own extension direction is L2, and L1>L2.

[0006] Furthermore, the range of L1 is 70 mm to 80 mm; the range of L2 is 40 mm to 50 mm.

[0007] Furthermore, L1 / L2=n, wherein the value range of n is 1<n<2.

[0008] Furthermore, the angle between the positive electrode tab and the outer side of the positive electrode sheet is an obtuse angle, and the angle between the negative electrode tab and the outer side of the negative electrode sheet is an obtuse angle.

[0009] Furthermore, the angle between the positive electrode tab and the outer side of the positive electrode sheet is in the range of 92° to 100°; the angle between the negative electrode tab and the outer side of the negative electrode sheet is in the range of 92° to 100°.

[0010] Furthermore, the battery cell also includes a positive electrode connecting piece and a negative electrode connecting piece, the positive electrode connecting piece is welded to the positive electrode ear, and the negative electrode connecting piece is welded to the negative electrode ear, wherein the total weld print area between the positive electrode connecting piece and the positive electrode ear is greater than the total weld print area between the negative electrode connecting piece and the negative electrode ear.

[0011] Furthermore, there are multiple weld marks between the positive electrode connecting sheet and the positive electrode lug, and there is one weld mark between the negative electrode connecting sheet and the negative electrode lug, and the size of each weld mark between the positive electrode connecting sheet and the positive electrode lug is the same as the size of the weld mark between the negative electrode connecting sheet and the negative electrode lug.

[0012] Furthermore, each weld mark between the positive electrode connecting sheet and the positive electrode lug, and each weld mark between the negative electrode connecting sheet and the negative electrode lug has a width ranging from 6 mm to 10 mm, and a length ranging from 15 mm to 20 mm.

[0013] Furthermore, the number of the core packs is two, and the positive electrode connecting sheet and the negative electrode connecting sheet each include a first connecting portion, a second connecting portion, and an intermediate portion connected between the first connecting portion and the second connecting portion;

[0014] The first connection portion and the second connection portion of the positive electrode connecting sheet are respectively welded to the positive electrode tabs of the two core packages, and the first connection portion and the second connection portion of the negative electrode connecting sheet are respectively welded to the negative electrode tabs of the two core packages.

[0015] Furthermore, the core package is a laminated core package.

[0016] In a second aspect, the present application also provides a battery, comprising a housing and a battery cell accommodated in the housing, wherein the battery cell is the battery cell described above.

[0017] The above introduces a battery cell, including at least one core package, each of the core packages includes a positive electrode ear, a negative electrode ear, a negative electrode sheet and a positive electrode sheet, the positive electrode ear is connected to the positive electrode sheet, the negative electrode ear is connected to the negative electrode sheet, the positive electrode ear extends in a direction away from the positive electrode sheet, the negative electrode ear extends in a direction away from the negative electrode sheet, the length of the positive electrode ear perpendicular to its own extension direction is L1, the length of the negative electrode ear perpendicular to its own extension direction is L2, and L1>L2. Therefore, by increasing the length L1 of the positive electrode ear, the weldable area of ​​the positive electrode ear can be increased, thereby improving the overcurrent capacity of the battery cell during fast charging and significantly reducing the DCR of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of a battery cell provided in this application;

[0019] Figure 2 An exploded schematic diagram of the battery cell provided for this application;

[0020] Figure 3 A schematic diagram of the structure of the connection of two core packages provided for this application;

[0021] Figure 4 A schematic diagram of the structure of the battery provided for this application;

[0022] Figure 5 Schematic diagram of the exploded view of the battery provided for this application.

[0023] The reference numerals in the embodiments of the present application are described as follows:

[0024] Battery cell: 10; core package: 11; positive ear: 111; negative ear: 112; positive electrode sheet: 113; negative electrode sheet: 114; positive electrode connecting sheet: 12; negative electrode connecting sheet: 13; first connecting part: 121, 131; second connecting part: 122, 132; middle part: 123, 133; weld marks: 20, 21; battery: 300; outer shell: 31; bottom shell: 311; top cover assembly: 312; injection hole: 3121; positive electrode column: 32; negative electrode column: 33; sealing rubber particles: 34; top insulating sheet: 35; explosion-proof valve: 36; blue film: 37; auxiliary welding sheets: 38, 39. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0026] See also Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the structure of the battery cell according to the embodiment of the present application. Figure 2 The exploded schematic diagram of the battery cell of the present application embodiment is shown in the figure. As shown in the figure, the battery cell 10 of the present application includes at least one core package 11, and each core package 11 includes a positive electrode ear 111, a negative electrode ear 112, a positive electrode sheet 113 and a negative electrode sheet 114. The positive electrode ear 111 is connected to the positive electrode sheet 113, and the negative electrode ear 112 is connected to the negative electrode sheet 114. The positive electrode ear 111 extends in a direction away from the positive electrode sheet 113, and the negative electrode ear 112 extends in a direction away from the negative electrode sheet 114. Figure 2 As shown, both the positive ear 111 and the negative ear 112 extend in the y direction. The length of the positive ear 111 perpendicular to its own extension direction y is L1, and the length of the negative ear 112 perpendicular to its own extension direction y is L2, that is, the lengths of the positive ear 111 and the negative ear 12 in the x direction are L1 and L2 respectively, where L1 is greater than L2. Therefore, by increasing the length L1 of the positive ear 111, the weldable area of ​​the positive ear 111 can be increased, thereby improving the overcurrent capacity of the battery cell during fast charging, and significantly reducing the DCR of the battery cell.

[0027] Furthermore, in the embodiment of the present application, the range of the length L1 is 70 mm to 80 mm, such as 72 mm, 75 mm or 78 mm, etc.; the range of the length L2 is 40 mm to 50 mm, such as 43 mm, 45 mm or 48 mm, etc.

[0028] Furthermore, L1 / L2=n, wherein the value range of n is 1<n<2, and n can be, for example, 1.2, 1.5, 1.7 or 1.9.

[0029] Continue reading Figure 2 In the embodiment of the present application, the angle a1 between the positive electrode ear 111 and the positive electrode sheet 113 on the outside is an obtuse angle, and the angle a2 between the negative electrode ear 112 and the negative electrode sheet 114 on the outside is an obtuse angle. By setting the obtuse angle, the electrode ear can be prevented from folding during the manufacturing process. Furthermore, the angle a1 between the positive electrode ear 111 and the positive electrode sheet 113 on the outside is in the range of 92° to 100°, for example, it can be 95° or 98°; the angle a2 between the negative electrode ear 112 and the negative electrode sheet 114 on the outside is in the range of 92° to 100°, for example, it can be 95° or 98°. Of course, in other embodiments, the values ​​of the angle a1 and the angle a2 may also be different, for example, the angle a1 may be 97°, and the angle a2 may be 93°.

[0030] Combination Figure 3 The battery cell 10 also includes a positive electrode connecting piece 12 and a negative electrode connecting piece 13. The positive electrode connecting piece 12 is welded to the positive electrode ear 111, so that the positive electrode ear 111 can be connected to the positive electrode column of the battery through the positive electrode connecting piece 12; the negative electrode connecting piece 13 is welded to the negative electrode ear 112, so that the negative electrode ear 112 can be connected to the negative electrode column of the battery through the negative electrode connecting piece 13.

[0031] In some embodiments, the number of core packs 11 may be two, the positive electrode connecting sheet 12 includes a first connecting portion 121, a second connecting portion 122, and an intermediate portion 123 connected between the first connecting portion 121 and the second connecting portion 122; the negative electrode connecting sheet 13 includes a first connecting portion 131, a second connecting portion 132, and an intermediate portion 133 connected between the first connecting portion 131 and the second connecting portion 132. The first connecting portion 121 and the second connecting portion 122 of the positive electrode connecting sheet 12 are respectively welded to the positive electrode ears 111 of the two core packs 11, and the first connecting portion 131 and the second connecting portion 132 of the negative electrode connecting sheet 13 are respectively welded to the negative electrode ears 112 of the two core packs 11. In other embodiments, the positive electrode connecting sheet and the negative electrode connecting sheet may also be other shapes such as a straight strip structure, which may be specifically set according to actual needs.

[0032] The total weld area between the positive electrode connecting sheet 12 and the positive electrode ear 111 is greater than the total weld area between the negative electrode connecting sheet 13 and the negative electrode ear 112. It can be understood that when there are multiple core packs 11, the total weld area between the positive electrode connecting sheet 12 and the positive electrode ear 111 refers to the total weld area between the positive electrode connecting sheet 12 and the positive electrode ear 111 of each core pack 11. By making the weld area between the positive electrode connecting sheet 12 and the positive electrode ear 111 larger, the current capacity of the battery cell can be improved, which is conducive to reducing the DCR of the battery cell.

[0033] Alternatively, if Figure 3 As shown, there may be multiple weld marks 20 between the positive electrode connecting sheet 12 and the positive electrode ear 111 of each core package 11, and there is only one weld mark between the negative electrode connecting sheet 13 and the negative electrode ear 112 of each core package 11. The size of each weld mark between the positive electrode connecting sheet 12 and the positive electrode ear 111 is the same as the size of the weld mark between the negative electrode connecting sheet 13 and the negative electrode ear 112, and the weld mark size includes the length and width of the weld mark. Further, the width range of each weld mark 20 between the positive electrode connecting sheet 12 and the positive electrode ear 111 and the weld mark 21 between the negative electrode connecting sheet 13 and the negative electrode ear 112 is 6mm to 10mm, and the length range is 15mm to 20mm. Among them, the width can be, for example, 6.5mm, 8mm or other values, and the length can be, for example, 16mm, 18mm or other values.

[0034] In the embodiment of the present application, the core package 11 is a laminated core package. More specifically, the core package 11 also includes a first diaphragm and a second diaphragm. The first diaphragm, the negative electrode sheet 114, the second diaphragm, and the positive electrode sheet 113 are stacked in sequence from bottom to top to form a laminated core package.

[0035] See also Figure 4 and Figure 5 The embodiment of the present application further provides a battery 300, including a housing 31 and a battery cell 10 accommodated in the housing 31, and the battery cell 10 is the battery cell described in the above embodiment.

[0036] Furthermore, the housing 31 includes a bottom shell 311 and a top cover assembly 312, the bottom shell 311 has an opening, and the battery cell 10 is located in the bottom shell 311, and the bottom shell 311 can be, for example, an aluminum shell. The battery cell 10 is accommodated in the bottom shell 311, and the top cover assembly 312 is fixed on the bottom shell 311 and covers the opening of the bottom shell 311. The top cover assembly 312 is provided with a positive electrode column 32 and a negative electrode column 33, and the positive electrode ear 111 of the battery cell 10 is connected to the positive electrode column 32 through the positive electrode connecting sheet 12, and the negative electrode ear 112 of the battery cell 10 is connected to the negative electrode column 33 through the negative electrode connecting sheet 13.

[0037] Furthermore, the battery 300 further comprises a sealing sheet and a sealing rubber particle 34. The top cover assembly 312 is provided with a liquid injection hole 3121. The sealing rubber particle 34 is plugged into the liquid injection hole 3121 to enhance the sealing effect of the battery. The sealing sheet seals the liquid injection hole 3121. The sealing sheet may be, for example, an aluminum sheet, and is used to weld and seal the liquid injection hole 3121.

[0038] Furthermore, an isolation bracket may be provided between the positive electrode connecting sheet 12 and the core pack 11 , and between the negative electrode connecting sheet 13 and the battery core pack 11 , respectively, and the isolation bracket may prevent the core pack 11 from contacting the positive electrode connecting sheet 12 and the negative electrode connecting sheet 13 .

[0039] Furthermore, the battery 300 also includes a top insulating sheet 35, and an explosion-proof valve 36 is arranged on the top cover assembly 312. The top insulating sheet 35 covers the side of the top cover assembly 312 facing away from the battery cell 10, and the top insulating sheet 35 has an opening corresponding to the position of the explosion-proof valve 36 to expose the explosion-proof valve 36. The insulation effect of the top insulating sheet 35 helps to prevent the battery cell 10 from short circuiting.

[0040] Optionally, a bottom support sheet is provided between the bottom of the battery cell 10 and the bottom shell 311, and the bottom support sheet can prevent the battery cell 10 and the bottom shell 311 from contacting each other and causing a short circuit. In addition, the outer surface of the battery cell 10 is coated with a protective film layer to prevent the negative electrode ear 112 from directly contacting the bottom shell 311 and causing a short circuit.

[0041] The outer surface of the bottom shell 311 is covered with a blue film 37 to prevent the battery from short circuiting.

[0042] Optionally, the positive electrode tab 111 and the negative electrode tab 112 of the battery cell 10 are located on the same side of the battery cell 10. In other embodiments, the positive electrode tab 111 and the negative electrode tab 112 may also be located on different sides of the battery cell 10.

[0043] Optionally, auxiliary welding tabs are provided on both the positive electrode connecting tab 12 and the negative electrode connecting tab 13, such as an auxiliary welding tab 38 is provided on the positive electrode connecting tab 12, and an auxiliary welding tab 39 is provided on the negative electrode connecting tab 13, so as to protect the electrode tab from being welded.

[0044] The utility model of the present application also provides a method for manufacturing the battery 300, which is specifically as follows:

[0045] (1) homogenizing the positive and negative electrodes, uniformly dispersing the positive electrode active material and the negative electrode active material with the conductive agent and the binder in a certain mass ratio in a solvent, thereby obtaining a positive electrode slurry and a negative electrode slurry;

[0046] (2) coating the positive and negative electrodes, stably coating the evenly dispersed positive electrode slurry and negative electrode slurry onto the positive electrode collector and negative electrode collector respectively;

[0047] (3) positive and negative electrode sheeting, rolling the coated positive electrode collector and negative electrode collector to a specified thickness, and then cutting them into specified sizes to obtain positive electrode sheets and negative electrode sheets;

[0048] (4) Lamination assembly: stacking the prepared positive electrode sheets and negative electrode sheets into a core package, wherein a separator is provided between the positive electrode sheets and the negative electrode sheets, and assembling them with the outer shell;

[0049] (5) Baking: Baking the assembled battery in a vacuum oven to a specified moisture value;

[0050] (6) Injecting electrolyte into the battery through the injection hole on the top cover assembly and leaving it to stand until the electrolyte completely soaks the electrode;

[0051] (7) Formation, activating the battery and discharging the gas generated by the side reactions in the battery by pumping negative pressure;

[0052] (8) Capacity division: the formed batteries are sealed and welded, and the capacity is divided according to the pre-set process.

[0053] The above introduces a battery cell, including at least one core package, each of the core packages includes a positive electrode ear, a negative electrode ear, a negative electrode sheet and a positive electrode sheet, the positive electrode ear is connected to the positive electrode sheet, the negative electrode ear is connected to the negative electrode sheet, the positive electrode ear extends in a direction away from the positive electrode sheet, the negative electrode ear extends in a direction away from the negative electrode sheet, the length of the positive electrode ear perpendicular to its own extension direction is L1, the length of the negative electrode ear perpendicular to its own extension direction is L2, and L1>L2. Therefore, by increasing the length L1 of the positive electrode ear, the weldable area of ​​the positive electrode ear can be increased, thereby improving the overcurrent capacity of the battery cell during fast charging and significantly reducing the DCR of the battery cell.

[0054] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A battery cell, characterized in that: comprising at least one core package; Each core package includes a positive electrode ear, a negative electrode ear, a negative electrode sheet and a positive electrode sheet, the positive electrode ear is connected to the positive electrode sheet, the negative electrode ear is connected to the negative electrode sheet, the positive electrode ear extends in a direction away from the positive electrode sheet, the negative electrode ear extends in a direction away from the negative electrode sheet, the length of the positive electrode ear perpendicular to its own extension direction is L1, the length of the negative electrode ear perpendicular to its own extension direction is L2, and L1>L2.

2. The battery cell according to claim 1, characterized in that: The range of L1 is 70 mm to 80 mm; the range of L2 is 40 mm to 50 mm.

3. The battery cell according to claim 2, characterized in that: The L1 / L2=n, wherein the value range of n is 1<n<2.

4. The battery cell according to claim 1, characterized in that: The angle between the positive electrode ear and the outer side of the positive electrode sheet is an obtuse angle, and the angle between the negative electrode ear and the outer side of the negative electrode sheet is an obtuse angle.

5. The battery cell according to claim 3, characterized in that: The included angle between the positive electrode tab and the outer side of the positive electrode sheet is in the range of 92° to 100°; the included angle between the negative electrode tab and the outer side of the negative electrode sheet is in the range of 92° to 100°.

6. The battery cell according to any one of claims 1 to 5, characterized in that: The battery cell also includes a positive electrode connecting piece and a negative electrode connecting piece, wherein the positive electrode connecting piece is welded to the positive electrode ear, and the negative electrode connecting piece is welded to the negative electrode ear, wherein the total weld print area between the positive electrode connecting piece and the positive electrode ear is greater than the total weld print area between the negative electrode connecting piece and the negative electrode ear.

7. The battery cell according to claim 6, characterized in that: There are multiple weld marks between the positive electrode connecting sheet and the positive electrode ear, and there is one weld mark between the negative electrode connecting sheet and the negative electrode ear. The size of each weld mark between the positive electrode connecting sheet and the positive electrode ear is the same as the size of the weld mark between the negative electrode connecting sheet and the negative electrode ear.

8. The battery cell according to claim 7, characterized in that: The width of each weld mark between the positive electrode connecting sheet and the positive electrode ear and the weld mark between the negative electrode connecting sheet and the negative electrode ear are both in the range of 6 mm to 10 mm, and the length is both in the range of 15 mm to 20 mm.

9. The battery cell according to claim 6, characterized in that: The number of the core packs is two, and the positive electrode connecting sheet and the negative electrode connecting sheet each include a first connecting portion, a second connecting portion, and an intermediate portion connected between the first connecting portion and the second connecting portion; The first connection portion and the second connection portion of the positive electrode connecting sheet are respectively welded to the positive electrode tabs of the two core packages, and the first connection portion and the second connection portion of the negative electrode connecting sheet are respectively welded to the negative electrode tabs of the two core packages.

10. The battery cell according to any one of claims 1 to 5, characterized in that: The core package is a laminated core package.

11. A battery, characterized in that: The invention comprises a shell and a battery cell accommodated in the shell, wherein the battery cell is the battery cell according to any one of claims 1 to 10.

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