Battery electrode plate, cylindrical battery and manufacturing method of cylindrical battery

Abstract

The invention provides a battery electrode plate, a cylindrical battery and a manufacturing method of the cylindrical battery. The battery electrode pole piece comprises a coating area coated with an electrode material along the length direction of the pole piece and a light foil area not coated with the electrode material, and the light foil area is alternately provided with a plurality of inclined grooves and a plurality of inclined bulges. The cylindrical battery comprises a positive pole piece, a negative pole piece and a diaphragm, and the positive pole piece and / or the negative pole piece are / is the battery electrode piece disclosed by the invention. The manufacturing method of the cylindrical battery comprises the step of flattening the positive and negative end faces of the battery cell, and the flattening direction is the same as the inclination direction of the inclined bulge. The problems of breaking and chip falling of the inclined protrusions are relieved, and the electrolyte injection speed and the electrolyte injection effect can be improved. Besides, the end face of the tab position has more sheet structures and can be in surface contact with the bus bar, so that the welding residual quantity, the welding strength and the welding fool-proof effect can be effectively improved, and the internal resistance of the battery is further reduced.

Description

Technical Field

[0001] The present invention relates to the field of batteries, and in particular to a battery electrode sheet. The present invention also relates to a cylindrical battery and a manufacturing method thereof. Background Art

[0002] A typical battery includes a positive electrode sheet, a negative electrode sheet and a separator, and the separator is inserted between the positive electrode sheet and the negative electrode sheet as an insulator. When the positive electrode slurry is coated on the positive electrode sheet (usually aluminum foil), a part of the area not coated with the slurry is reserved on one edge, which is called the positive light foil area; when the negative electrode slurry is coated on the negative electrode sheet (usually copper foil), a part of the area not coated with the slurry is reserved on one edge, which is called the negative light foil area. After the positive electrode sheet, the negative electrode sheet and the separator are assembled and wound to form a core winding body (battery cell), the positive light foil area is flattened to form the end face of the positive pole tab, and the negative light foil area is flattened to form the end face of the negative pole tab. The end face of the pole tab needs to be welded to the busbar so that the current of the battery can be output from the busbar.

[0003] In order to make the bending of the bare foil area better adapt to the flattening process, the prior art usually performs a flattening process on the bare foil area. There are still some problems with the end face of the pole tab obtained after flattening. For example, when the end face of the pole tab is welded to the busbar due to the small contact area, there is less welding residue and low welding strength, which leads to an increase in the internal resistance of the battery. In addition, the end face of the pole tab obtained after flattening in the prior art is usually relatively tight, which has a certain impact on the injection speed and injection effect of the electrolyte. Another prior art is to shear the bare foil area perpendicular to the length direction of the pole piece to obtain a slit or notch, and then bend it toward the center and compact it. Such a scheme makes it difficult to obtain a flat plane.

[0004] Therefore, it is necessary to provide a battery electrode plate, a cylindrical battery and a method for manufacturing the same to at least partially solve the above problems. Summary of the invention

[0005] The object of the present invention is to provide a battery electrode plate, a cylindrical battery and a manufacturing method thereof. The battery electrode plate of the present invention comprises a coating area coated with an electrode material and a bare foil area not coated with an electrode material along the length direction of the plate, wherein the bare foil area is alternately provided with a plurality of inclined grooves and a plurality of inclined protrusions. The cylindrical battery of the present invention comprises a positive electrode plate, a negative electrode plate and a diaphragm, wherein the positive electrode plate and / or the negative electrode plate are the battery electrode plates of the present invention. The manufacturing method of the cylindrical battery of the present invention comprises flattening the positive and negative end surfaces of the battery cell, wherein the flattening direction is the same as the inclination direction of the inclined protrusion. Such a design can reduce the resistance of the flattening wheel, and the flattening wheel can more smoothly press the inclined protrusion onto the end surface of the pole ear, thereby alleviating the problem of breakage and chipping. Moreover, the inclined protrusions after being pressed are stacked together like "fish scales", which are more layered, and are conducive to improving the injection speed and injection effect of the electrolyte. In addition, compared with the problem of weak point contact welding between the end face of the pole tab and the busbar obtained in the prior art, the end face of the pole tab of the present invention has more sheet structures, which can make surface contact with the busbar, and can effectively improve the welding residue, welding strength and welding foolproof effect, thereby reducing the internal resistance of the battery. The battery can be, but is not limited to, a lithium-ion battery, a nickel-cadmium battery, a nickel-hydrogen battery, a polymer battery, etc.

[0006] According to one aspect of the present invention, a battery electrode plate is provided, comprising a coated area coated with electrode material and a bare foil area not coated with electrode material along the length direction of the plate, wherein the bare foil area is alternately provided with a plurality of inclined grooves and a plurality of inclined protrusions.

[0007] In one embodiment, the inclined groove and the inclined protrusion have the same inclination angle, which is 35 to 85 degrees, preferably 40 to 80 degrees, and more preferably 50 to 70 degrees.

[0008] In one embodiment, the ratio of the depth of the inclined groove to the width of the smooth foil area is 0.2 to 1, preferably 0.3 to 0.8, and more preferably 0.4 to 0.6.

[0009] In one embodiment, the width of the inclined groove gradually widens from one end to the other end of the pole piece.

[0010] In one embodiment, the ratio of the maximum width to the minimum width of the inclined groove is 5:1 to 9:1, preferably 6:1 to 8:1, and more preferably 7:1.

[0011] In one embodiment, the ratio of the width of the inclined protrusion to the width of the adjacent inclined groove is 1:1 to 5:1, preferably 1:1 to 3:1, and more preferably 2:1.

[0012] In one embodiment, the width D of the inclined groove is nAs the number of pole piece windings n increases, D n =D1+n×D a , where D1 is the width of the inclined groove on the innermost circle of the winding core, D n is the width of the inclined groove 21 of the nth winding core, D a is a predetermined value.

[0013] In one embodiment, D1 is 0.2 to 2 mm, preferably 0.5 to 1.5 mm, and more preferably 1 mm.

[0014] In one embodiment, the width W of the inclined protrusion is 1 to 5 mm, preferably 1.5 to 3.5 mm, and more preferably 2 mm.

[0015] In one embodiment, the inclined groove includes an inclined groove bottom, and the inclined groove bottom includes a rounded corner structure or an arc structure.

[0016] In one embodiment, the inclined protrusion includes an inclined protrusion top, and the inclined protrusion top includes a rounded structure or an arc structure.

[0017] According to another aspect of the present invention, there is provided a cylindrical battery, comprising a positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet and / or the negative electrode sheet is the battery electrode sheet as described above, the electrode material of the positive electrode sheet is a positive electrode material, and the electrode material of the negative electrode sheet is a negative electrode material.

[0018] In one embodiment, the positive electrode sheet, the negative electrode sheet and the separator are wound into a battery cell, and the battery cell is flattened so that the end portion substantially forms a plane.

[0019] In one embodiment, the plane includes a plurality of plate-like pieces, and the plate-like pieces are formed by the inclined protrusions.

[0020] In one embodiment, the area of ​​the flakes is 1 to 10 mm. 2 , preferably 2 to 5 mm 2 .

[0021] In one embodiment, the area of ​​a single flake-shaped piece accounts for 2 to 8% of the area of ​​the plane.

[0022] In one embodiment, the total area of ​​the plurality of flake-like pieces accounts for 40 to 90% of the area of ​​the plane.

[0023] In one embodiment, the cylindrical battery further includes a bus bar, and the bus bar is at least partially welded to the sheet-shaped small piece.

[0024] According to another aspect of the present invention, there is provided a method for manufacturing a cylindrical battery, comprising the following steps:

[0025] Step 1: Winding the positive electrode sheet, the negative electrode sheet and the separator into a battery core; wherein the positive electrode sheet and the negative electrode sheet are both the battery electrode sheets as described above, the electrode material of the positive electrode sheet is a positive electrode material, and the electrode material of the negative electrode sheet is a negative electrode material;

[0026] Step 2: Flatten the positive and negative ends of the battery cell;

[0027] Step 3: Weld the busbar to the flattened positive and negative end surfaces;

[0028] Step 4: Assemble the welded battery cells with other battery components, and then inject liquid and form them.

[0029] In one embodiment, in step 2, the flattening direction is the same as the inclination direction of the inclined protrusion. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to better understand the above and other purposes, features, advantages and functions of the present invention, reference may be made to the preferred embodiments shown in the accompanying drawings. The same reference numerals in the accompanying drawings refer to the same components. It should be understood by those skilled in the art that the accompanying drawings are intended to schematically illustrate the preferred embodiments of the present invention and have no limiting effect on the scope of the present invention, and the components in the drawings are not drawn to scale.

[0031] Figure 1 A schematic diagram of the structure of an electrode plate according to a preferred embodiment of the present invention;

[0032] Figure 2 A schematic diagram of the structure of an electrode sheet according to another preferred embodiment of the present invention;

[0033] Figure 3 The end face picture of the tab obtained by the prior art;

[0034] Figure 4 This is a picture of the end face of the pole ear obtained by the present invention.

[0035] Reference numerals:

[0036] 1Coating area

[0037] 2. Light Foil Area

[0038] 21 inclined grooves

[0039] 211 inclined groove bottom

[0040] 22 inclined protrusion

[0041] 221 inclined raised top

[0042] D Inclined groove width

[0043] W inclined protrusion width

[0044] h Depth of inclined groove

[0045] α Tilt angle DETAILED DESCRIPTION

[0046] Now, with reference to the accompanying drawings, the specific embodiments of the present invention are described in detail. What is described here is only the preferred embodiment of the present invention, and those skilled in the art can think of other ways to implement the present invention on the basis of the preferred embodiment, and the other ways also fall into the scope of the present invention. In some embodiments, in order to avoid confusion with the present invention, some technical features known in the art are not described.

[0047] definition

[0048] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those of ordinary skill in the art. In the event of a conflict, the present invention (including definitions) shall prevail. Only exemplary methods and materials are described below, and structures, methods and materials similar or equivalent to those described in the present invention can be used for experiments or tests of the present invention. The structures, materials, methods and examples disclosed in the present invention are illustrative only and are not intended to be limiting.

[0049] For the recitation of numerical ranges of the present invention, each intermediate number with the same degree of precision is expressly contemplated. For example, for the range of 6 to 9, the numbers 7 and 8 are contemplated in addition to 6 and 9, and for the range of 6.0 to 7.0, the numbers 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9 and 7.0 are expressly contemplated.

[0050] Battery electrode

[0051] Figure 1-Figure 2 The battery electrode sheet according to the present invention is shown. First of all, it should be noted that the directional terms and position terms in the present invention should be understood as relative directions and positions, rather than absolute directions and positions. The directional terms and position terms in the present invention can refer to Figure 1-Figure 2 The exemplary structure shown is explained.

[0052] In the prior art, the flattening process is usually performed on the plain foil area. The tab end surface obtained after flattening still has some problems, such as the small contact area when welding the tab end surface to the busbar, resulting in less welding residue and low welding strength, which in turn increases the internal resistance of the battery. In addition, the tab end surface obtained after flattening in the prior art is usually relatively tight (such as Figure 3 As shown in the figure, it has a certain influence on the injection speed and injection effect of the electrolyte. Another prior art is to cut the light foil area perpendicular to the length direction of the pole piece to obtain a slit or notch, and then bend it toward the center and compact it. Such a solution is difficult to use in smaller batteries.

[0053] The present invention provides a battery electrode plate. Figure 1-Figure 2 A battery electrode pole piece according to a preferred embodiment of the present invention comprises a coating area 1 coated with electrode material and a bare foil area 2 not coated with electrode material along the length direction of the pole piece, wherein the bare foil area is alternately provided with a plurality of inclined grooves 21 and a plurality of inclined protrusions 22.

[0054] It should be noted that the structure of the inclined groove 21 and the inclined protrusion 22 of the present invention can be obtained by cutting off the inclined groove 21 portion of the foil material on the bare foil area 2 not coated with the electrode material through the laser cutting technology commonly used by those skilled in the art, or by other cutting means, such as die cutting. Therefore, the cutting means is not specifically limited in the present invention.

[0055] Please refer to Figure 2 For the convenience of preparation, the inclined groove 21 and the inclined protrusion 22 are parallel to each other, that is, the inclination angle of the two is ( Figure 2 As a preferred embodiment, the angle of inclination is 35 to 85 degrees, preferably 40 to 80 degrees, and more preferably 50 to 70 degrees. The present invention has found through experiments that when the angle of inclination α is 50 to 70 degrees, in the process of flattening and shaping, the flattening wheel (flattening along the inclined direction of the inclined protrusion 22) has less resistance, and better flatness can be obtained. It is to be understood that those skilled in the art can also set different angles as needed without departing from the scope of the present invention.

[0056] Please refer to Figure 2 The present invention provides a depth of the inclined groove 21, that is, a distance from the upper edge of the light foil area 2 to the bottom of the inclined groove 21 ( Figure 2 There is no special restriction as long as a good bending effect can be achieved. As a preferred embodiment, the ratio of the depth h of the inclined groove 21 to the width of the plain foil area 2 is 0.2 to 1 (i.e., cutting to the edge of the coating area 1), preferably 0.3 to 0.8, and more preferably 0.4 to 0.6.

[0057] In the process of preparing the battery cell, one end of the electrode plate is located at the innermost circle of the jelly roll core, and the other end is located at the outermost circle of the core. The width of the inclined groove 21 can be a fixed value. In one embodiment, in order to achieve a better flattening effect, as a preferred embodiment, the width of the inclined groove 21 ( Figure 2D) gradually widens from one end of the pole piece (corresponding to the innermost circle of the winding core) to the other end (corresponding to the outermost circle of the winding core). As a preferred embodiment, the ratio of the maximum width (corresponding to the outermost circle of the winding core) to the minimum width (corresponding to the innermost circle of the winding core) of the inclined groove 21 is 5:1 to 9:1, preferably 6:1 to 8:1, and more preferably 7:1. As a non-limiting embodiment, for example, the width of the inclined groove 21 of the innermost circle of the winding core is 1mm, the width of the inclined groove 21 of the outermost circle of the winding core is 7mm, and the width of the inclined groove 21 in the middle part of the two gradually increases (for example, in an arithmetic sequence) from 1mm to 7mm.

[0058] As another preferred embodiment, the width D of the inclined groove 21 is n As the number of pole piece windings n increases, D n =D1+n×D a , where D1 is the width of the inclined groove 21 of the innermost circle (first circle) of the winding core, D n is the width of the inclined groove 21 of the nth winding core, D a is a predetermined value, which is determined according to the core size and actual needs. As an example, D a It should be noted that in this embodiment, the width D of each circle of the inclined groove 21 is 0.05 to 2 mm, preferably 0.1 to 1 mm, and more preferably 0.5 mm. n is a constant value, and the end surface of the pole lug obtained by this design has better uniformity and flatness. As a preferred embodiment, D1 is 0.2 to 2 mm, preferably 0.5 to 1.5 mm, and more preferably 1 mm. For better understanding, as a non-limiting embodiment, for example, the width D1 of the inclined groove 21 of the innermost circle (the first circle) of the winding core is 1 mm, D a is 0.5mm, then according to D n =1+n, the width D2 of the second circle of the inclined groove 21 is 1.5 mm, and so on. In another embodiment, the width D2 of the inclined groove 21 is n It can be set to increase every two or three turns. Other settings can be thought of by those skilled in the art without departing from the scope of the present invention.

[0059] The present invention has a width ( Figure 2 As a preferred embodiment, the ratio of the width of the inclined protrusion 22 to the width of the adjacent inclined groove 21 is 1:1 to 5:1, preferably 1:1 to 3:1, and more preferably 2:1. As a further preferred embodiment, the width W of the inclined protrusion 22 is 1 to 5 mm, preferably 1.5 to 3.5 mm, and more preferably 2 mm.

[0060] The present invention has been found through experiments that Figure 2 The obtuse or acute angle structure of the inclined groove 21 and the inclined protrusion 22 shown in the figure is easy to break and chip during the flattening process. Therefore, the present invention improves the specific structure of the inclined groove 21 and the inclined protrusion 22 to alleviate the above problems. Figure 1 The lower end of the inclined groove 21 is the inclined groove bottom 211, and the inclined groove bottom 211 is designed to include a rounded corner structure or an arc structure. Figure 2 The acute angle structure and the obtuse angle structure at the bottom of the middle inclined groove 21 are adjusted to two rounded angle structures. Figure 2 The acute angle structure and the obtuse angle structure at the bottom of the inclined groove 21 are adjusted to an arc structure. As a further preferred embodiment, similarly, the upper end of the inclined protrusion 22 is an inclined protrusion top 221, and the inclined protrusion top 221 includes a rounded corner structure or an arc structure. The rounded corner structure refers to Figure 2 The acute angle structure and the obtuse angle structure at the top of the middle inclined protrusion 22 are adjusted to two rounded angle structures. The arc structure refers to Figure 2 The acute angle structure and the obtuse angle structure at the top of the middle inclined protrusion 22 are adjusted to an arc structure. Such design of the inclined groove 21 and the inclined protrusion 22 can improve the toughness of the inclined protrusion 22 and alleviate the problem of easy breakage and easy chipping during the flattening process.

[0061] It should be noted that the battery electrode sheet of the present invention can be a positive electrode sheet or a negative electrode sheet, and the electrode materials correspond to positive electrode materials and negative electrode materials respectively. The preparation of the electrode sheet coating can be prepared by conventional preparation methods in the art, and the present invention will not repeat them here.

[0062] In addition, another aspect of the present invention provides a cylindrical battery, comprising the battery electrode sheet as described above, wherein the positive electrode of the battery is the electrode sheet described in the present invention, or the negative electrode of the battery is the electrode sheet described in the present invention, or both are the electrode sheets described in the present invention.

[0063] Cylindrical battery

[0064] Another aspect of the present invention provides a cylindrical battery, comprising a positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet and / or the negative electrode sheet are the battery electrode sheets as described above, the electrode material of the positive electrode sheet is a positive electrode material, and the electrode material of the negative electrode sheet is a negative electrode material. As a preferred embodiment, the positive electrode sheet, the negative electrode sheet and the separator are wound into a battery cell, and the battery cell is flattened so that the end portion roughly forms a plane. Wherein, the plane includes a plurality of sheet-like small pieces, and the sheet-like small pieces are formed by the inclined protrusions 22.

[0065] As a further preferred embodiment, the area of ​​the flake-like pieces is 1 to 10 mm 2 , preferably 2 to 5 mm 2 . The area of ​​a single sheet-like block accounts for 2 to 8% of the area of ​​the plane. The total area of ​​a plurality of sheet-like blocks accounts for 40 to 90% of the area of ​​the plane. In addition, the cylindrical battery of the present invention may further include a busbar, which is at least partially welded to the sheet-like block.

[0066] Method for manufacturing cylindrical battery

[0067] Another aspect of the present invention provides a method for manufacturing a cylindrical battery, wherein the method uses the battery electrode sheet as described above. With the aforementioned battery electrode sheet structure known, those skilled in the art can use conventional preparation methods in the art to prepare the battery.

[0068] In order to better achieve the technical effect of the present invention, a preferred method for manufacturing a battery is introduced herein, but the application of the battery electrode sheet of the present invention is not limited thereby. The positive electrode sheet and the negative electrode sheet in the method are both the battery electrode sheets as described above, the electrode material of the positive electrode sheet is a positive electrode material, and the electrode material of the negative electrode sheet is a negative electrode material, and the method comprises the following steps:

[0069] Step 1: Winding the positive electrode sheet, the negative electrode sheet and the separator into a battery cell;

[0070] Step 2: Flatten the positive and negative ends of the battery cell;

[0071] Step 3: Weld the busbar to the flattened positive and negative end surfaces;

[0072] Step 4: Assemble the welded battery cells with other battery components, and then inject liquid and form them.

[0073] As a further preferred embodiment, the kneading direction in step 2 is the same as the inclination direction of the inclined protrusion 22. Such a step design combined with the structure of the inclined protrusion 22 can reduce the resistance of the kneading wheel, and more smoothly press the inclined protrusion 22 onto the end surface of the tab, thereby alleviating the problem of breakage and chipping. Moreover, the inclined protrusions 22 after being pressed are stacked together like "fish scales" (such as Figure 4 As shown in the figure, it is more layered, which is beneficial to improving the injection speed and injection effect of the electrolyte.

[0074] In addition, compared with the problem of weak point contact welding between the end face of the pole tab and the bus bar obtained in the prior art, the end face of the pole tab of the present invention has more sheet structures and can make surface contact with the bus bar, which can effectively improve the welding residue, welding strength and welding fool-proofing effect, thereby reducing the internal resistance of the battery.

[0075] The above description of various embodiments of the present invention is provided to one of ordinary skill in the relevant art for the purpose of description. It is not intended that the present invention be exclusive or limited to a single disclosed embodiment. As above, a person of ordinary skill in the field of the above teachings will understand the various substitutions and variations of the present invention. Therefore, although some alternative embodiments are specifically described, a person of ordinary skill in the art will understand or relatively easily develop other embodiments. The present invention is intended to include all substitutions, modifications and variations of the present invention described herein, as well as other embodiments that fall within the spirit and scope of the present invention described above.

Claims

1. A battery electrode plate, characterized in that: It comprises a coating area (1) coated with electrode material along the length direction of the pole piece and a bare foil area (2) not coated with electrode material, wherein the bare foil area is alternately provided with a plurality of inclined grooves (21) and a plurality of inclined protrusions (22).

2. A battery electrode plate according to claim 1, characterized in that: The inclined groove (21) and the inclined protrusion (22) have the same inclination angle, which is 35 to 85 degrees, preferably 40 to 80 degrees, and more preferably 50 to 70 degrees.

3. A battery electrode plate according to claim 1, characterized in that: The ratio of the depth of the inclined groove (21) to the width of the smooth foil area (2) is 0.2 to 1, preferably 0.3 to 0.8, and more preferably 0.4 to 0.

6.

4. A battery electrode plate according to claim 1, characterized in that: The width of the inclined groove (21) gradually widens from one end of the pole piece to the other end.

5. A battery electrode plate according to claim 4, characterized in that: The ratio of the maximum width to the minimum width of the inclined groove (21) is 5:1 to 9:1, preferably 6:1 to 8:1, and more preferably 7:

1.

6. A battery electrode plate according to claim 4, characterized in that: The ratio of the width of the inclined protrusion (22) to the width of the adjacent inclined groove (21) is 1:1 to 5:1, preferably 1:1 to 3:1, and more preferably 2:

1.

7. A battery electrode sheet according to claim 1, characterized in that: The width D of the inclined groove (21) n As the number of pole piece windings n increases, D n =D1+n×D a , where D1 is the width of the inclined groove (21) on the innermost circle of the winding core, D n is the width of the inclined groove (21) of the nth winding core, D a is a predetermined value.

8. A battery electrode plate according to claim 7, characterized in that: D1 is 0.2 to 2 mm, preferably 0.5 to 1.5 mm, and more preferably 1 mm.

9. A battery electrode sheet according to claim 7, characterized in that: The width W of the inclined protrusion (22) is 1 to 5 mm, preferably 1.5 to 3.5 mm, and more preferably 2 mm.

10. A battery electrode sheet according to claim 1, characterized in that: The inclined groove (21) comprises an inclined groove bottom (211), and the inclined groove bottom (211) comprises a rounded corner structure or an arc structure.

11. A battery electrode plate according to claim 1, characterized in that: The inclined protrusion (22) comprises an inclined protrusion top (221), and the inclined protrusion top (221) comprises a rounded corner structure or an arc structure.

12. A cylindrical battery, characterized in that: It comprises a positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet and / or the negative electrode sheet is a battery electrode sheet according to any one of claims 1 to 11, the electrode material of the positive electrode sheet is a positive electrode material, and the electrode material of the negative electrode sheet is a negative electrode material.

13. The cylindrical battery according to claim 12, characterized in that: The positive electrode sheet, the negative electrode sheet and the separator are wound into a battery cell, and the battery cell is flattened so that the end portion roughly forms a plane.

14. The cylindrical battery according to claim 13, characterized in that: The plane includes a plurality of plate-like pieces, and the plate-like pieces are formed by the inclined protrusions (22).

15. The cylindrical battery according to claim 14, characterized in that: The area of ​​the flakes is 1 to 10 mm 2 , preferably 2 to 5 mm 2 .

16. The cylindrical battery according to claim 14, characterized in that: The area of ​​a single flake-shaped piece occupies 2 to 8% of the area of ​​the plane.

17. The cylindrical battery according to claim 14, characterized in that: The total area of ​​the plurality of flake-shaped pieces accounts for 40 to 90% of the area of ​​the plane.

18. The cylindrical battery according to claim 16, characterized in that: Also included is a busbar that is at least partially welded to the sheet-like pieces.

19. A method for manufacturing a cylindrical battery, characterized in that: The steps include: Step 1, winding the positive electrode sheet, the negative electrode sheet and the separator into a battery core; wherein the positive electrode sheet and the negative electrode sheet are both the battery electrode sheets according to any one of claims 1 to 11, the electrode material of the positive electrode sheet is a positive electrode material, and the electrode material of the negative electrode sheet is a negative electrode material; Step 2: Flatten the positive and negative ends of the battery cell; Step 3: Weld the busbar to the flattened positive and negative end surfaces; Step 4: Assemble the welded battery cells with other battery components, and then inject liquid and form them.

20. The method for manufacturing a cylindrical battery according to claim 19, characterized in that: In step 2, the flattening direction is the same as the inclination direction of the inclined protrusion (22).

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