Electrode, cell and battery

Abstract

The present application provides a pole piece, a battery cell and a battery, wherein the pole piece includes a current collector, the current collector includes a body and an extension portion, the first side of the body is connected to the extension portion, the body is provided with a coating area, and the extension portion includes a curved edge away from the first side portion, wherein: the projection length of the line connecting the two ends of the curved edge on the first side portion is L; in the direction perpendicular to the first side portion, the distance between the midpoint of the line connecting the two ends of the curved edge and the curved edge is X; X and L satisfy: 0<X / L≤2%. With such a configuration, when the pole piece is rolled and the pole ear is welded by rolling welding, the ductility of the current collector is controlled, the curvature of the current collector is improved, and the ratio of X to L is ensured to be within the range of 0 to 2%, so that more pole ears can be welded to the extension portion of the pole piece, thereby improving the manufacturing yield in the process of making the current collector into the pole piece.

Description

Technical Field

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

[0002] With the rapid development of lithium-ion battery technology, further improving the electrical performance of batteries has become a key research and development direction for major battery manufacturers. Among them, composite current collectors are increasingly widely used in pole piece manufacturing due to their advantages in improving the nail penetration performance and impact resistance of battery cells. It is found in the prior art that due to the material complexity of composite current collectors, pole pieces produced based on composite current collectors have the problem of low manufacturing yield in some processes, resulting in a decrease in the electrical conductivity of the pole pieces and limited battery cell capacity. Therefore, how to improve the manufacturing yield of pole pieces made of composite current collectors in the process has become an important technical problem to be solved by technicians in this field. Utility Model Content

[0003] In view of this, the present application provides a pole piece to solve the problem of how to improve the yield rate of pole pieces made of composite current collectors in the prior art. The present application also provides a battery cell including the pole piece. The present application also provides a battery including the battery cell.

[0004] In order to achieve the above objectives, this application provides the following technical solutions:

[0005] A pole piece, comprising a current collector, the current collector comprising a body and an extension portion, a first side edge of the body being connected to the extension portion, the body being provided with a coating area, characterized in that the extension portion comprises a curved edge away from the first side edge, wherein:

[0006] The projection length of the line connecting the two ends of the curved edge on the first side edge is L;

[0007] In a direction perpendicular to the first side, the distance between the midpoint of the line connecting the two ends of the curved edge and the curved edge is X;

[0008] Furthermore, X and L satisfy the following relationship: 0<X / L≤2%.

[0009] Optionally, in a direction perpendicular to the current collector:

[0010] The thickness of the extension portion is H1, and the thickness of the main body is H2;

[0011] Among them, H1 and H2 satisfy: 1

[0012] Optionally, in a direction perpendicular to the current collector:

[0013] The thickness of the extension portion is H1, and the thickness of the main body is H2;​

[0014] Among them, H1 and H2 satisfy: 0

[0015] Optional,

[0016] The area of ​​the extension portion is S, and the surface density of the active material layer on one side of the coating area is M;

[0017] Among them, S and M satisfy: 0.5≤M / S≤50.

[0018] Optionally, the current collector includes a polymer layer and a metal layer disposed on both sides of the polymer layer.

[0019] In the direction perpendicular to the current collector, the thickness of the metal layer on one side is H3;

[0020] The surface density of the active material layer on one side of the coating area is M;

[0021] Among them, H3 and M satisfy: 10%≤H3 / M*100%≤60%.

[0022] Optional,

[0023] The value range of X is: 0<X≤20mm;

[0024] and / or,

[0025] The value range of L is: 3mm≤L≤300mm.

[0026] Optional,

[0027] The value range of H1 is: 2μm≤H1≤40μm;

[0028] and / or,

[0029] The value range of H2 is: 2μm≤H2≤40μm.

[0030] Optional,

[0031] The value range of H3 is: 0.1 μm ≤ H3 ≤ 15 μm;

[0032] and / or,

[0033] The value range of M is: 1 mg / cm 2 ≤M≤40mg / cm 2 .

[0034] A battery cell,

[0035] ​The battery cell is a laminated battery cell, the laminated battery cell comprises a positive electrode sheet, a negative electrode sheet and a pole tab, the positive electrode sheet and / or the negative electrode sheet is the pole sheet described in any one of the above, and the pole tab is welded to the extension portion; or,

[0036] The battery cell is a wound battery cell, and the wound battery cell includes a positive electrode sheet, a negative electrode sheet and a pole tab. The positive electrode sheet and / or the negative electrode sheet is the pole sheet described in any one of the above items, and the pole tab is welded to the extension portion.

[0037] A battery comprises the above-mentioned battery cell.

[0038] The pole piece provided by the present application includes a current collector, which includes a body and an extension portion, wherein the first side of the body is connected to the extension portion, and the body is provided with a coating area, characterized in that the extension portion includes a curved edge away from the first side edge, wherein: the projection length of the line connecting the two ends of the curved edge on the first side edge is L; in the direction perpendicular to the first side edge, the distance between the midpoint of the line connecting the two ends of the curved edge and the curved edge is X; X and L satisfy: 0<X / L≤2%. In this way, when the pole piece is rolled and the pole ear is welded by rolling welding, the ductility of the current collector is controlled, the curvature of the current collector is improved, and the ratio of X to L is ensured to be within the range of 0 to 2%, which can ensure that more pole ears are welded to the extension portion of the pole piece, thereby improving the manufacturing yield in the process of making the current collector into the pole piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0040] Figure 1 A schematic diagram of the partial structure of a pole piece provided in an embodiment of the present application;

[0041] Figure 2 It is a schematic diagram of the partial structure of the lower pole piece in another implementation mode;

[0042] Figure 3 Schematic diagram of current collector interval coating.

[0043] exist Figure 1-Figure 3 middle:

[0044] 1-main body, 2-extension part;

[0045] 11- first side edge, 21- curved side edge. DETAILED DESCRIPTION

[0046] The present application provides a pole piece. The present application also provides a battery cell including the pole piece. The present application also provides a battery including the battery cell.

[0047] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0048] like Figures 1 to 3 As shown, the embodiment of the present application provides a pole piece, which can form a battery cell with a diaphragm and other structures, and the battery cell, electrolyte and shell and other structures together form a battery. The pole piece includes a current collector, and the current collector includes a body and an extension, wherein the coating area is the area where the body is coated with active material and / or an insulating layer, and the extension is the area where the current collector is used to provide a welding position for the pole ear.

[0049] Specifically, the first side of the body is connected to the extension part, the body is provided with a coating area, the extension part includes a curved side away from the first side, the projection length of the line connecting the two ends of the curved side 21 on the first side 11 is L; in the direction perpendicular to the first side 11, the distance between the midpoint of the line connecting the two ends of the curved side 21 and the curved side 21 is X; and X and L satisfy: 0<X / L≤2%. The ratio of X to L reflects the degree of curvature of the curved side 21. Here, ensuring that the ratio of X to L is within the above range can ensure that the curvature of the curved side 21 is small, and can improve the welding yield when the pole ear is welded to the extension part 2 by rolling welding, that is, it can ensure that more pole ears are welded to the extension part 2, so as to improve the manufacturing yield in the process of pole piece processing.

[0050] It should be noted that since the current collector includes a main body 1 and an extension portion 2, an active material layer and / or an insulating layer is coated in the area where the main body 1 is located to form the current collector into a material strip to be rolled. When a roller device is used to roll the above-mentioned material strip, since the thickness of the area where the main body 1 is located is greater than the thickness of the area where the extension portion 2 is located, this will cause the elongation rate of the current collector located in the area of ​​the main body 1 to be greater than the elongation rate of the current collector located in the area of ​​the extension portion 2, which will cause the extension portion 2 to bend. After the rolled material strip is cut, the edge of the extension portion 2 away from the main body 1 is a bent edge 21.

[0051] It should also be noted that the first side edge 11 refers to the boundary between the main body 1 and the extension portion 2, that is, the edge of the main body 1 close to the extension portion 2. The extension line direction of the first side edge 11 is Figure 1 and Figure 2 The direction indicated by the double-headed arrow A is perpendicular to the first side edge 11. Figure 1 and Figure 2 The two ends of the curved edge 21 are Figure 1 The areas shown in C and D.

[0052] For example, the ratio of X to L can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, etc. The smaller the ratio of X to L, the higher the yield of the electrode sheet made of the current collector in the process.

[0053] It should also be noted that the above-mentioned current collector can be a metal foil current collector, such as copper foil, aluminum foil, etc.; it can also be a composite current collector, which includes a polymer layer and a metal layer arranged on the surface of both sides of the polymer layer. The polymer layer is usually PE (polyethylene) or PP (polypropylene), etc.

[0054] It should also be noted that the coating area refers to the area on the current collector where the active material layer is coated, or the coating area refers to the area on the current collector where the active material layer and ceramic are coated.

[0055] For the pole piece of the above structure, when the pole piece is rolled, exemplarily, when the pole ear is welded by roll welding, the ductility of the current collector is controlled, the curvature of the current collector is improved, and the ratio of X and L is ensured to be in the range of 0 to 2%. This can ensure that more pole ears are welded to the extension portion 2 of the pole piece, thereby improving the manufacturing yield in the process of making the current collector into a pole piece.

[0056] In some embodiments, in the direction perpendicular to the current collector: the thickness of the extension 2 is H1, and the thickness of the main body 1 is H2; H1 and H2 satisfy: 1

[0057] It should be noted that the direction of the vertical current collector is not shown in the figure. The direction of the vertical current collector is perpendicular to Figure 1 The directions of the double-headed arrows A and B.

[0058] Exemplarily, the ratio of H1 to H2 may be 1.1, 1.2, 1.3, 1.5, 1.6, 1.8, 2, etc. The smaller the ratio of H1 to H2, the better the forming effect of the pole piece, and the higher the production efficiency and production yield of the pole piece.

[0059] ​In some embodiments, in the direction perpendicular to the current collector: the thickness of the extension 2 is H1, and the thickness of the main body 1 is H2; H1 and H2 satisfy: 0

[0060] Exemplarily, the difference between H1 and H2 may be: 0.5 μm, 0.8 μm, 1 μm, 1.5 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, etc. The smaller the difference between H1 and H2, the better the forming effect of the pole piece, and the higher the production efficiency and production yield of the pole piece.

[0061] In some embodiments, the area of ​​the extension 2 is S, and the surface density of the single-side active material layer in the coating area is M; wherein S and M satisfy: 0.5≤M / S≤50. Specifically, the ratio of the area of ​​the extension 2 to the surface density of the single-side active material layer in the coating area is ensured to be within the above range, and the area of ​​the extension 2 can be limited. The larger the area of ​​the extension 2, the smaller the shared current density, which is more conducive to a chemical system with a thick surface density, the smaller the internal resistance, the lower the temperature rise, and the longer the cycle life of the battery.

[0062] Exemplarily, the ratio of S to M can be: 0.5, 0.6, 0.8, 1, 1.5, 2, 3, 5, 10, 15, 20, 30, 40, 45, 48, 50, etc.

[0063] It should be noted that the unit of the area S of the extension portion 2 is cm 2 The unit of the surface density M of the active material layer on one side of the coating area is mg / cm 2 , where the ratio of M to S is only numerically calculated without unit calculation.

[0064] ​In some embodiments, the current collector includes a polymer layer and a metal layer disposed on the surfaces of both sides of the polymer layer. In the direction perpendicular to the current collector, the thickness of the single-sided metal layer is H3; the surface density of the single-sided active material layer in the coating area is M; H3 and M satisfy: 10% ≤ H3 / M*100% ≤ 60%. Since the thicker the metal layer in the composite current collector, the stronger the electronic and thermal conductivity, the better the electrical performance of the battery cell; but the more metal materials used, the heavier the foil weight, the lower the mass energy density of the battery cell, and the higher the cost. The greater the surface density of the single-sided active material layer, the greater the electric energy density, and the greater the energy density of the battery, the thicker the metal layer in the composite current collector is required to conduct electricity. Controlling the thickness of the metal layer and the surface density of the single-sided active material layer within the above range can ensure that the electronic and thermal conductivity of the battery composed of the above-mentioned pole pieces are strong, while avoiding excessive reduction in energy density and excessive cost.

[0065] It should be noted that, taking the example of the active material layer being coated on both sides of the current collector in the coating area of ​​the pole piece, the test method for the single-sided surface density of the coating area is: first weigh the weight of the coating area under a specific area (S) as m pole piece; then calculate the weight of the foil as m foil; then the single-sided surface density is: M (surface density) = (m pole piece - m foil) / 2S.

[0066] Exemplarily, the ratio between H3 and M can be: 10%, 12%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 58%, 60%, etc.

[0067] It should be noted that the unit of the thickness H3 of the single-sided metal layer is μm, and the unit of the surface density M of the single-sided active material layer in the coating area is mg / cm 2 , where the ratio of H3 to S is only numerically calculated without unit calculation.

[0068] In some embodiments, the value range of X is: 0<X≤20mm; and / or, the value range of L is: 3mm≤L≤300mm. And the ratio of X to L satisfies the relationship of 0<X / L≤2%. By setting the values ​​of X and L to the above relationship, the manufacturing yield in the electrode manufacturing process can be improved, and the electrode structure can be made compact, so that the electrode has better cycle performance, conductivity and energy density.

[0069] Exemplarily, X can be 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1mm, 1.5mm, 2mm, 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 15mm, 18mm, 20mm, etc.; L can be 3mm, 5mm, 8mm, 10mm, 20mm, 30mm, 50mm, 80mm, 100mm, 150mm, 200mm, 250mm, 280mm, 300mm, etc.

[0070] In some embodiments, the value range of H1 is: 2μm≤H1≤40μm; and / or, the value range of H2 is: 2μm≤H2≤40μm. And the ratio of H1 to H2 satisfies the relationship of 1

[0071] Exemplarily, H1 can be: 2μm, 3μm, 5μm, 8μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, etc.; H2 can be: 2μm, 3μm, 5μm, 8μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, etc.

[0072] In some embodiments, the value range of H3 is: 0.1 μm ≤ H3 ≤ 15 μm; and / or the value range of M is: 1 mg / cm 2 ≤M≤40mg / cm 2 . And the ratio of H3 to M satisfies the relationship of 10%≤H3 / M*100%≤60%. By setting the values ​​of H3 and M to the above relationship, it is possible to ensure that the battery composed of the above-mentioned pole pieces has strong electronic and thermal conductivity while avoiding excessive reduction in energy density and excessive cost, and making the pole piece structure compact, so that the pole piece has better cycle performance, conductivity and energy density.

[0073] For example, H3 may be: 0.1 μm, 0.2 μm, 0.5 μm, 1 μm, 2 μm, 5 μm, 8 μm, 10 μm, 12 μm, 14 μm, 15 μm, etc.; M may be: 1 mg / cm 2 , 2mg / cm 2 、3mg / cm 2 , 5mg / cm 2 , 8mg / cm 2 、10mg / cm 2 、15mg / cm 2 ​, 20mg / cm 2 , 25mg / cm 2 、30mg / cm 2 、35mg / cm 2 , 40mg / cm 2 etc.

[0074] A battery cell includes the above-mentioned pole piece. Since the battery cell includes the pole piece, the beneficial effects of the battery cell brought by the pole piece can be found in the above content and will not be repeated here.

[0075] In some embodiments, the battery cell is a laminated battery cell, the laminated battery cell includes a positive electrode sheet, a negative electrode sheet and a tab, the positive electrode sheet and / or the negative electrode sheet is any one of the above-mentioned electrode sheets, and the tab is welded to the extension portion 2;

[0076] In some embodiments, when the battery cell is a wound core, the battery cell can be a multi-pole-tab wound battery cell, which includes a positive electrode sheet, a negative electrode sheet and a pole tab, the positive electrode sheet and / or the negative electrode sheet is a pole sheet of any one of the above items, and the pole tab is welded to the extension portion 2; the battery cell can also be a full-pole-tab wound battery cell, which includes a positive electrode sheet, a negative electrode sheet and a pole tab, the positive electrode sheet and / or the negative electrode sheet is a pole sheet of any one of the above items, and the pole tab is welded to the extension portion 2.

[0077] A battery includes the above-mentioned battery cell. Since the battery includes the battery cell, the beneficial effects brought by the battery cell can be found in the above content and will not be repeated here.

[0078] In addition, the present application records the test process to form three groups of performance comparisons of embodiments and comparative examples. The following three groups of embodiments and comparative examples are used to further specifically describe the contents disclosed in the present application. These embodiments are only used for illustrative purposes, because it is obvious to those skilled in the art to make various modifications and changes within the scope of the contents disclosed in the present application.

[0079] 1. First Group of Examples and Comparative Examples

[0080] (1) Preparation instructions

[0081] In this group of embodiments and comparative examples, the control variables are X and L, X is the distance between the midpoint of the line connecting the two ends of the curved edge 21 and the curved edge 21 in the direction perpendicular to the first side 11, L is the projection length of the line connecting the two ends of the curved edge 21 on the first side 11, and the other setting parameters are the same. In the embodiment, eight pole pieces with different X / L ratios are set; in the comparative example, two pole pieces with different X / L ratios are set. Please refer to Table 1 for details.

[0082] (2) Experimental tests and results

[0083] The pole pieces in the embodiment and the comparative example are subjected to the roll welding process on the extension part 2 respectively, and statistics are made on whether the welding results of the formed pole ear and the extension part 2 are successful.

[0084] Table 1

[0085]

[0086]

[0087] It can be seen from the data in Table 1 that when 0<X / L≤2% is satisfied, the comprehensive performance such as process yield and cell internal resistance is optimal.

[0088] 2. Second Group of Examples and Comparative Examples

[0089] (1) Preparation instructions

[0090] In this group of embodiments and comparative examples, the control variables are H1 and H2, H1 is the thickness at the extension 2, H2 is the thickness of the body 1, and the other setting parameters are the same. In the embodiment, four pole pieces with H1 / H2 at different ratios are set, and in the comparative example, two pole pieces with H1 / H2 at different ratios are set; in the embodiment, four pole pieces with H1-H2 at different differences are set; in the comparative example, two pole pieces with H1-H2 at different differences are set. Please refer to Table 2 and Table 3 for details.

[0091] (2) Experimental tests and results

[0092] The electrode sheets in the embodiment and the comparative example are subjected to lamination, packaging, liquid injection, formation, sorting and other processes according to the cell manufacturing process to complete the cell preparation, and the following test results are statistically analyzed:

[0093] Table 2

[0094]

[0095] Table 3

[0096]

[0097] From the data in Table 2 and Table 3, it can be seen that when H I When the value of / H2 or H1-H2 is within an appropriate range, good energy density and cycle life can be ensured.

[0098] 3. The third group of embodiments and comparative examples

[0099] (1) Preparation instructions

[0100] In this group of embodiments and comparative examples, the control variables are H3 and M, H3 is the thickness of the single-sided metal layer in the direction perpendicular to the current collector, M is the surface density of the single-sided active material layer in the coating area, and the other setting parameters are the same. In the embodiment, seven pole pieces with different H3 / M ratios are set; in the comparative example, four pole pieces with different H3 / M ratios are set. Please refer to Table 4 for details.

[0101] (2) Experimental tests and results

[0102] The electrode sheets in the embodiment and the comparative example are designed with the current collector and surface density of the negative electrode sheet, and the processes of lamination, packaging, liquid injection, formation, sorting, etc. are carried out according to the battery cell manufacturing process to complete the battery cell preparation, and the following test results are statistically analyzed:

[0103] Table 4

[0104]

[0105]

[0106] It can be seen from the data in Table 4 that when the values ​​of H3 and M are within the appropriate range, the energy density and cycle life can be guaranteed to be good.

[0107] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0108] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0109] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0110] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0111] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly explain the technical solutions and cannot be used to limit the scope of protection of the present application.

[0112] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A pole piece, characterized in that: A current collector is included, the current collector includes a body and an extension portion, a first side edge of the body is connected to the extension portion, the body is provided with a coating area, and the extension portion includes a curved edge away from the first side edge, wherein: The projection length of the line connecting the two ends of the curved edge on the first side edge is L; In a direction perpendicular to the first side, the distance between the midpoint of the line connecting the two ends of the curved edge and the curved edge is X; Furthermore, X and L satisfy the following relationship: 0<X / L≤2%.

2. The pole piece according to claim 1, characterized in that: In the direction perpendicular to the current collector: The thickness of the extension portion is H1, and the thickness of the main body is H2; Among them, H1 and H2 satisfy: 1<H1 / H2≤2.

3. The pole piece according to claim 1, characterized in that: In the direction perpendicular to the current collector: The thickness of the extension portion is H1, and the thickness of the main body is H2; Among them, H1 and H2 satisfy: 0<H1-H2≤10μm.

4. The pole piece according to claim 1, characterized in that: The area of ​​the extension portion is S, and the surface density of the active material layer on one side of the coating area is M; Among them, S and M satisfy: 0.5≤M / S≤50.

5. The pole piece according to claim 1, characterized in that: The current collector includes a polymer layer and a metal layer disposed on both sides of the polymer layer. In the direction perpendicular to the current collector, the thickness of the metal layer on one side is H3; The surface density of the active material layer on one side of the coating area is M; Among them, H3 and M satisfy: 10%≤H3 / M*100%≤60%.

6. The pole piece according to claim 1, characterized in that: The value range of X is: 0<X≤20mm; and / or, The value range of L is: 3mm≤L≤300mm.

7. The pole piece according to claim 2 or 3, characterized in that: The value range of H1 is: 2μm≤H1≤40μm; and / or, The value range of H2 is: 2μm≤H2≤40μm.

8. The pole piece according to claim 5, characterized in that: The value range of H3 is: 0.1 μm ≤ H3 ≤ 15 μm; and / or, The value range of M is: 1 mg / cm 2 ≤M≤40mg / cm 2 .

9. A battery cell, characterized in that: The battery cell is a laminated battery cell, the laminated battery cell comprises a positive electrode sheet, a negative electrode sheet and a pole ear, the positive electrode sheet and / or the negative electrode sheet is a pole sheet as claimed in any one of claims 1 to 8, and the pole ear is welded to the extension portion; or, The battery cell is a wound battery cell, and the wound battery cell includes a positive electrode sheet, a negative electrode sheet and a pole tab. The positive electrode sheet and / or the negative electrode sheet is a pole sheet as described in any one of claims 1 to 8, and the pole tab is welded to the extension portion.

10. A battery, characterized in that: Comprising the battery cell as claimed in claim 9.

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