Full-tab battery electrode sheet assembly, full-tab battery jelly roll and sodium-ion battery

Abstract

A full-tab battery electrode sheet assembly, a full-tab battery jelly roll and a sodium-ion battery. The full-tab battery electrode sheet assembly comprises: a positive electrode sheet, which sequentially comprises a positive electrode coated area, a bonding area and a positive electrode blank area in the direction of width thereof, wherein the positive electrode coated area is coated with a positive electrode material, and the positive electrode blank area forms a positive electrode tab after being subjected to winding and flattening treatments; and a negative electrode sheet, which sequentially comprises a negative electrode coated area and a negative electrode blank area in the direction of width thereof, wherein the negative electrode coated area is coated with a negative electrode material, and the negative electrode blank area forms a negative electrode tab after being subjected to winding and flattening treatments. The flattening ratio of the positive electrode tab ranges from 60% to 73%, and the flattening ratio of the negative electrode tab ranges from 75% to 87%. The flattening ratio is obtained by means of dividing the difference between the width of a corresponding tab before flattening and the width of same after flattening by the width of same before flattening.

Description

Full-tab battery pole piece assembly, full-tab battery core and sodium-ion battery Technical Field

[0001] The present invention relates to a full-tab battery pole piece assembly and a full-tab battery core, and also to a sodium-ion battery. More specifically, the present invention relates to a sodium-ion battery with high welding quality and low aluminum shavings generated during flattening. Background Art

[0002] The tabs of the full-tab battery roll are flattened and then welded to the collecting plate. If the flattening distance is too small, the voltage difference of the battery cell drop test will be large, resulting in poor impact resistance of the battery. If the flattening distance is too large, more aluminum chips will be generated during the flattening process, which will easily form a short circuit and cause the battery's safety performance to deteriorate.

[0003] To this end, it is hoped to propose a full-tab battery pole piece assembly, a full-tab battery coil and a corresponding sodium-ion battery, so that the voltage difference in the battery cell drop test is small while also ensuring that no excessive aluminum chips are generated during the flattening process. Summary of the Invention

[0004] According to a first aspect of the present invention, a full-tab battery electrode sheet assembly is proposed, comprising: a positive electrode sheet having a rectangular shape and capable of being wound into a cylindrical shape, the positive electrode sheet including, in sequence, a positive electrode coating area, an adhesive area and a positive electrode blank area in its width direction, the positive electrode coating area being coated with a positive electrode material, the adhesive area being provided with an adhesive material, and the positive electrode blank area forming a positive electrode tab after being wound and flattened; a negative electrode sheet having a rectangular shape and capable of being wound into a cylindrical shape, the negative electrode sheet including, in sequence, a negative electrode coating area and a negative electrode blank area in its width direction, the negative electrode coating area being coated with a negative electrode material, and the negative electrode blank area forming a negative electrode tab after being wound and flattened; wherein the flattening ratio of the positive electrode tab is in the range of 60% to 73%, and the flattening ratio of the negative electrode tab is in the range of 75% to 87%, and the flattening ratio is the difference between the width of the corresponding tab before flattening and the width after flattening divided by the width before flattening.

[0005] According to this solution, by selecting an appropriate flattening ratio during the flattening process, the voltage difference of the battery cell drop test is reduced while ensuring that no excessive aluminum chips are generated during the flattening process.

[0006] In some aspects, the width of the positive electrode blank area may be less than 6.5 mm, and the width of the negative electrode blank area may be less than 7.0 mm.

[0007] In some embodiments, the width of the positive electrode blank area may be greater than 5.5 mm, and the width of the negative electrode blank area may be greater than 6.0 mm.

[0008] In some embodiments, the width of the positive electrode blank area may be 6.0 mm, and the width of the negative electrode blank area may be 6.5 mm.

[0009] In some aspects, the bonding material may include ceramic.

[0010] According to the second aspect of the present invention, a full-tab battery core is proposed, which includes the full-tab battery pole piece assembly according to the first aspect of the present invention. The full-tab battery core is formed by winding the positive pole piece, the separator and the negative pole piece stacked in sequence around a winding axis, and the winding axis is parallel to the width direction.

[0011] According to this solution, by selecting an appropriate flattening ratio during the flattening process, the voltage difference of the battery cell drop test is reduced while ensuring that no excessive aluminum chips are generated during the flattening process.

[0012] In some embodiments, the positive electrode tab and the negative electrode tab can be formed on both sides of the full-tab battery roll in the width direction.

[0013] In some embodiments, the positive electrode tab may extend from the separator, and the negative electrode tab may extend from the separator.

[0014] In some embodiments, the width of the positive electrode tab can be between 1.8 mm and 2.2 mm, and the width of the negative electrode tab can be between 0.8 mm and 1.2 mm.

[0015] According to a third aspect of the present invention, a sodium ion battery is provided, comprising the full-tab battery core according to the second aspect of the present invention.

[0016] According to this solution, by selecting an appropriate flattening ratio during the flattening process, the voltage difference of the battery cell drop test is reduced while ensuring that no excessive aluminum chips are generated during the flattening process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG1 shows a schematic diagram of a positive electrode sheet according to an embodiment of the present invention;

[0018] FIG2 shows a schematic diagram of a negative electrode sheet according to an embodiment of the present invention;

[0019] FIG3 is a schematic diagram of a full-tab battery core according to an embodiment of the present invention, wherein the tabs have not yet been flattened;

[0020] FIG4 shows a schematic diagram of a full-tab battery roll according to an embodiment of the present invention, wherein the tabs have been flattened. DETAILED DESCRIPTION

[0021] In order to make the purpose, scheme and advantages of the technical solution of the present invention more clear, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of specific embodiments of the present invention. Unless otherwise specified, the terms used herein have the common meanings in the art. The same reference numerals in the drawings represent the same components.

[0022] The full-tab battery electrode sheet assembly includes a positive electrode sheet 100 and a negative electrode sheet 200. The positive electrode sheet 100, the negative electrode sheet 200, and the separator 300 are wound to form a full-tab battery roll core 10. As shown in Figure 1, the positive electrode sheet 100 includes a positive electrode coating area 110, an adhesive area 120, and a positive electrode blank area 130 in sequence along its width direction. The positive electrode coating area 110 is coated with a positive electrode material, and the adhesive area 120 is provided with an adhesive material (for example, a material including ceramic). The positive electrode blank area 130 forms a positive electrode tab 140 after winding and flattening. As shown in Figure 2, the negative electrode sheet 200 includes a negative electrode coating area 210 and a negative electrode blank area 230 in sequence along its width direction. The negative electrode coating area 210 is coated with a negative electrode material, and the negative electrode blank area 230 forms a negative electrode tab 240 after winding and flattening.

[0023] As shown in FIG3 , the full-tab battery core 10 is formed by winding a positive electrode sheet 100, a separator 300, and a negative electrode sheet 200 stacked in sequence around a winding axis, which is parallel to the width direction. The positive electrode tab 140 can extend from the separator 300, and the negative electrode tab 240 can extend from the separator 300. The width of the positive electrode tab 140 corresponds to the width of the positive electrode blank area 130 in FIG1 , and the width of the negative electrode tab 240 corresponds to the difference between the width of the negative electrode blank area 230 in FIG2 and the width of the bonding area 120 in FIG1 . Preferably, the positive electrode tab 140 and the negative electrode tab 240 can be formed on both sides of the full-tab battery core 10 in the width direction. After the positive electrode tab 140 and the negative electrode tab 240 in FIG3 are flattened, as shown in FIG4 , the width of the positive electrode tab 140 and the negative electrode tab 240 is reduced after the flattening process, and the reduction ratio is referred to as the flattening ratio in this article.

[0024] The flattening ratio of the tabs 140 and 240 during the flattening process (i.e., the difference between the width of the tabs 140 and 240 before flattening and the width after flattening divided by the width before flattening) is crucial to the performance of the sodium-ion battery. If the flattening ratio is too small, the voltage difference of the battery cell drop test is large, which makes the impact resistance of the sodium-ion battery poor; and if the flattening ratio is too large, more aluminum chips are generated during the flattening process, which makes it easy to form a short circuit, resulting in a deterioration in the safety performance of the sodium-ion battery. Therefore, it is necessary to select a suitable flattening ratio so that the voltage difference of the battery cell drop test is small while also ensuring that no excessive aluminum chips are generated during the flattening process.

[0025] To this end, the performance of sodium ion batteries formed by flattening the positive electrode tab 140 and the negative electrode tab 240 at different flattening ratios was tested, and the test results are shown in Table 1.

[0026] Table 1 Sodium ion battery performance test

[0027] As can be seen from Table 1, when the positive electrode flattening ratio is less than 60% and the negative electrode flattening ratio is less than 75%, the voltage drop of the battery cell drop test is significantly larger. Therefore, in order to make the sodium-ion battery have better impact resistance (i.e., the voltage drop of the battery cell drop test is smaller), the positive electrode flattening ratio should be designed to be greater than 60%, and the negative electrode flattening ratio should be designed to be greater than 75%. On the other hand, in order to prevent excessive aluminum chips from being generated during the flattening process and affecting the performance of the sodium-ion battery, the positive electrode flattening ratio should be designed to be less than 73%, and the negative electrode flattening ratio should be designed to be less than 87%.

[0028] When the width of the positive electrode tab 140 after flattening is within the range of 1.8 mm to 2.2 mm (e.g., 2 mm), and the width of the negative electrode tab 240 after flattening is within the range of 0.8 mm to 1.2 mm (e.g., 1 mm), in order to meet the requirement that the flattening ratio is not too small to prevent the deterioration of the impact resistance of the sodium ion battery, the width of the positive electrode tab 140 before flattening is greater than 5.5 mm, and the width of the negative electrode tab 240 before flattening is greater than 5.0 mm. On the other hand, in order to meet the requirement that the flattening ratio is not too large to prevent excessive aluminum chips from being generated during the flattening process and affecting the performance of the sodium ion battery, the width of the positive electrode tab 140 before flattening is less than 6.5 mm, and the width of the negative electrode tab 240 before flattening is less than 6.0 mm.

[0029] The width of the positive electrode tab 140 before flattening is equal to the width of the positive electrode blank area 130, so the width of the positive electrode blank area 130 is designed to be within the range of 5.5 mm and 6.5 mm. The width of the negative electrode tab 240 before flattening is equal to the width of the negative electrode blank area 230 minus half the width of the bonding area 120, so the width of the negative electrode blank area 230 is designed to be within the range of 6.0 mm and 7.0 mm. Preferably, the width of the positive electrode blank area 130 can be 6.0 mm, and the width of the negative electrode blank area 230 can be 6.5 mm.

[0030] This document describes in detail several exemplary embodiments of the present invention with reference to preferred embodiments. However, it will be understood by those skilled in the art that various modifications and variations may be made to the above-mentioned specific embodiments without departing from the spirit of the present invention, and that the various technical features and structures proposed in the present invention may be combined without exceeding the scope of protection of the present invention, which is determined by the appended claims.

Claims

1. A full-tab battery pole piece assembly, characterized in that: include: A positive electrode sheet having a rectangular shape and capable of being wound into a cylindrical shape, the positive electrode sheet comprising, in order along its width direction, a positive electrode coating region, an adhesive region, and a positive electrode blank region, wherein the positive electrode coating region is coated with a positive electrode material, the adhesive region is provided with an adhesive material, and the positive electrode blank region forms a positive electrode tab after being wound and flattened; A negative electrode sheet having a rectangular shape and capable of being wound into a cylindrical shape, the negative electrode sheet comprising, in order along its width direction, a negative electrode coating region and a negative electrode blank region, the negative electrode coating region being coated with a negative electrode material, the negative electrode blank region forming a negative electrode tab after being wound and flattened; The flattening ratio of the positive electrode tab is in the range of 60% to 73%, and the flattening ratio of the negative electrode tab is in the range of 75% to 87%, and the flattening ratio is the difference between the width of the corresponding tab before flattening and the width after flattening divided by the width before flattening.

2. The full-tab battery pole piece assembly according to claim 1, characterized in that: The width of the positive electrode blank area is less than 6.5 mm, and the width of the negative electrode blank area is less than 7.0 mm.

3. The full-tab battery pole piece assembly according to claim 2, characterized in that: The width of the positive electrode blank area is greater than 5.5 mm, and the width of the negative electrode blank area is greater than 6.0 mm.

4. The full-tab battery pole piece assembly according to claim 3, characterized in that: The width of the positive electrode blank area is 6.0 mm, and the width of the negative electrode blank area is 6.5 mm.

5. The full-tab battery pole piece assembly according to claim 1, characterized in that: The bonding material includes ceramic.

6. A full-tab battery core, characterized in that: The full-tab battery core includes a full-tab battery pole sheet assembly according to any one of claims 1 to 5, and the full-tab battery core is formed by winding the positive pole sheet, the separator and the negative pole sheet stacked in sequence around a winding axis, and the winding axis is parallel to the width direction.

7. The full-tab battery core according to claim 6, characterized in that: The positive electrode tab and the negative electrode tab are formed on both sides of the full-tab battery roll in the width direction.

8. The full-tab battery core according to claim 7, characterized in that: The positive electrode tab extends from the separator, and the negative electrode tab extends from the separator.

9. The full-tab battery core according to claim 6, characterized in that: The width of the positive electrode tab is between 1.8 mm and 2.2 mm, and the width of the negative electrode tab is between 0.8 mm and 1.2 mm.

10. A sodium ion battery, characterized in that: Comprising the full-tab battery roll core according to any one of claims 6 to 9.

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