Pole piece, battery cell and battery

Abstract

The utility model provides a pole piece, a battery cell and a battery, and relates to the technical field of batteries, the pole piece comprises a current collector and an active layer and an insulating layer which are located on the current collector, the active layer comprises a first main body region and an edge region which are connected, and the insulating layer comprises a second main body region and a first side region close to the active layer; a thickness of the first side region of the insulating layer is less than a thickness of the second body region of the insulating layer. The ratio of the minimum thickness of the edge region to the thickness of the first body region is 0.95-1.05. According to the pole piece provided by the embodiment of the invention, the overall thickness difference of the active layer can be effectively reduced, so that the thickness of the active layer on the current collector is more uniform. Therefore, after the pole pieces are wound or stacked, the accumulation of thickness difference can be effectively reduced, and the thickness difference between the middle main body part and the edge of the battery cell can be effectively reduced. The content of the active layer can be effectively improved, so that the energy density of the battery cell is effectively improved.

Description

Technical Field

[0001] This application relates to the technical field of batteries, and particularly to an electrode sheet, an electric core and a battery. Background Art

[0002] A battery is a component that converts chemical energy into electrical energy and has a very wide range of applications in daily life and work. For example, lithium-ion batteries are often used in various electronic devices such as mobile phones, cameras, laptops, and tablets to provide power for the electronic devices. They play a very important role in people's life and work.

[0003] A lithium-ion battery includes an electrode sheet. The electrode sheet includes a current collector and an active layer and an insulating layer coated on the current collector. Generally, in the process of coating the active layer on the current collector, the portion of the active layer near the edge has a thinning area. The thickness of the thinning area is usually relatively thin, and the thickness of the thinning area usually differs from the thickness of the main body area of the active layer by several micrometers. After multiple winding or laminating, the thickness difference will accumulate, resulting in a difference in thickness between the edge and the main body area of the electrode sheet reaching several millimeters, greatly reducing the energy density of the electric core. Summary of the Utility Model

[0004] This application provides an electrode sheet, an electric core and a battery, which can effectively improve the energy density at the edge of the electric core.

[0005] One aspect of this application provides an electrode sheet, which includes a current collector and an active layer and an insulating layer located on the current collector;

[0006] The active layer includes a connected first main body area and an edge area. The insulating layer is arranged adjacent to the edge area of the active layer. The insulating layer includes a second main body area and a first side area close to the active layer. The thickness of the first side area of the insulating layer is less than the thickness of the second main body area of the insulating layer;

[0007] The ratio of the minimum thickness of the edge area to the thickness of the first main body area is 0.95 to 1.05 。

[0008] By making the ratio of the minimum thickness of the edge area of the active layer to the thickness of the first main body area be 0.95 to 1.05, this can effectively reduce the overall thickness difference of the active layer, make the thickness of the active layer on the current collector more uniform, can effectively reduce the thickness difference between the middle main body part and the edge of the electrode sheet, and make the overall thickness of the electrode sheet more uniform. After the electrode sheet is wound or stacked, the accumulation of the thickness difference can be effectively reduced, and the thickness difference between the middle main body part and the edge of the electric core can be effectively reduced. It can effectively increase the content of the active layer, thereby effectively increasing the energy density of the electric core.

[0009] In a possible implementation manner, from one end of the edge region close to the first main body region to the end of the edge region far from the first main body region, the thickness of the edge region gradually decreases.

[0010] In a possible implementation manner, the ratio of the thickness of the highest point of the second main body region to the thickness of the highest point of the first main body region is 1:1 to 1:4.

[0011] In a possible implementation manner, the current collector includes a connected current collecting region and a tab region;

[0012] The active layer is located on the current collecting region, and the second main body region of the insulating layer is located on the tab region.

[0013] In a possible implementation manner, the distance from the highest point of the second main body region to the edge region is a, the distance from the highest point of the second main body region to the end of the insulating layer far from the edge region is b, and the value of a is less than or equal to the value of b;

[0014] And / or, 0.2 mm ≤ a ≤ 1.5 mm;

[0015] And / or, 1.5 mm ≤ b ≤ 3 mm.

[0016] In a possible implementation manner, the ratio of the distance a from the highest point of the second main body region to the edge region to the length of the tab region is 0.1 to 0.3.

[0017] In a possible implementation manner, the ratio of the thickness of the highest point of the second main body region to the thickness of the end of the edge region close to the insulating layer is 1:1 to 3:1.

[0018] In a possible implementation manner, there is a gap between at least the partial insulating layer and the edge region, and the ratio of the gap to the width of the insulating layer is less than 0.3;

[0019] And / or, the width of the gap is less than or equal to 0.5 mm.

[0020] In a possible implementation manner, the gap is located in the current collecting region or in the tab region.

[0021] The second aspect of the present application provides an electric core, including a first electrode tab, a second electrode tab and a separator, and the first electrode tab is the electrode tab described in any one of the above.

[0022] In a possible implementation manner, along the direction from the current collecting region to the tab region of the first electrode tab, the highest point of the insulating layer of the first electrode tab exceeds the edge of the second electrode tab.

[0023] The third aspect of the present application provides a battery, including the above-mentioned battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 It is a schematic structural diagram of a pole piece provided by an embodiment of the present application;

[0026] Figure 2 It is a cross-sectional view of a pole piece provided by an embodiment of the present application;

[0027] Figure 3 It is a physical diagram of a cross-section of a pole piece provided by an embodiment of the present application;

[0028] Figure 4 It is a schematic structural diagram of a current collector provided by an embodiment of the present application.

[0029] REFERENCE NUMERALS

[0030] 100 - pole piece;

[0031] 110 - current collector;

[0032] 111 - pole piece area;

[0033] 112 - tab area;

[0034] 120 - active layer;

[0035] 121 - first main area;

[0036] 122 - edge area;

[0037] 130 - insulating layer;

[0038] 131 - second main area;

[0039] 132 - first side area;

[0040] 140 - gap. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Apparently, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0042] As described in the background art above, a lithium-ion battery includes a pole piece, and the pole piece includes a current collector and an active layer coated on the current collector. Generally, during the process of coating the active layer on the current collector, the portion of the active layer near the edge has a thinning region, and the thickness of the thinning region is usually relatively thin. The thickness of the thinning region usually differs from that of the main body region of the active layer by several micrometers. After multiple winding or laminating operations, the thickness difference will accumulate, causing the thickness difference between the edge and the main body region of the pole piece to reach several millimeters. During the hot pressing and forming process of the pole piece, a depression will appear on one side of the cell connecting tab region, resulting in less pressure on the edge of the pole piece, reducing the adhesiveness at the edge of the pole piece, and decreasing the energy density at the edge of the cell.

[0043] To solve the above problems, the embodiments of the present application provide a pole piece. By making the ratio of the minimum thickness of the edge region of the active layer to the thickness of the first main body region be 0.95 - 1.05, the overall thickness difference of the active layer can be effectively reduced, making the thickness of the active layer on the current collector more uniform. This can effectively reduce the thickness difference between the middle main body part and the edge of the pole piece, making the overall thickness of the pole piece more uniform. After winding or stacking the pole piece, the accumulation of the thickness difference can be effectively reduced, and the thickness difference between the middle main body part and the edge of the cell can be effectively reduced. The content of the active layer can be effectively increased, thereby effectively increasing the energy density of the cell.

[0044] The pole piece provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0045] Figure 1 It is a schematic structural diagram of a pole piece provided by the embodiments of the present application. Figure 2 It is a cross-sectional view of a pole piece provided by the embodiments of the present application. Figure 3 It is a physical diagram of the cross-section of a pole piece provided by the embodiments of the present application.

[0046] The embodiments of the present application provide a pole piece 100. The pole piece 100 can be a positive pole piece, and the positive pole piece can be stacked with a negative pole piece to form a cell. Refer to Figure 1 As shown, the pole piece 100 can include a current collector 110, an active layer 120 located on the current collector 110, and an insulating layer 130. The insulating layer 130 can be disposed adjacent to the active layer 120.

[0047] Among them, in combination with Figure 2 and Figure 3 As shown, the active layer 120 may include a connected first main region 121 and an edge region 122. The insulating layer may be disposed adjacent to the edge region 122 of the active layer 120, that is, the edge region 122 is located between the first main region 121 and the insulating layer 130. The insulating layer 130 may include a second main region 131 and a first side region 132 close to the active layer 120, that is, the first side region 132 is located between the edge region 122 and the second main region 131, and the thickness of the first side region 132 of the insulating layer 130 is less than the thickness of the second main region 131 of the insulating layer 130.

[0048] Among them, the demarcation point between the first main region 121 and the first edge region 122 can be determined in the following way: in the direction from the edge region 122 of the active layer 120 to the first main region 121 of the active layer 120, every 50 μm is used as a test point, and the position where the thickness increase rate between two adjacent test points is less than 1% is the demarcation point between the first main region 121 and the first edge region 122.

[0049] Correspondingly, the demarcation point between the second main region 131 and the first side region 132 in the insulating layer 130 can also be determined by the method for determining the demarcation point between the first main region 121 and the first edge region 122.

[0050] Among them, as shown in Figure 2 , the ratio of the minimum thickness d2 of the edge region 122 to the thickness d1 of the first main region 121 may be 0.95 - 1.05.

[0051] This can effectively reduce the thickness difference between the first main region 121 and the edge region 122 of the active layer 120, making the overall thickness of the active layer 120 more uniform.

[0052] For example, the active layer 120 may be disposed on the current collector 110 by coating. Specifically, before coating the active layer 120 on the current collector 110, two rows of tapes may be pasted on the current collector 110, and there is a gap between the two rows of tapes. The active layer 120 is coated between the two rows of tapes so that the active layer 120 fills the gap between the two rows of tapes. Among them, during the process of coating the active layer 120, the part of the active layer 120 between the two tapes may be coated more evenly, so that the thinner thinning area on the active layer 120 is located on the tape.

[0053] After the active layer 120 is coated and dried, the tape can be torn off, leaving only the active layer 120 on the current collector 110. In the process of tearing off the tape, the thinner area of ​​the active layer 120 on the tape will be removed from the current collector 110 together with the tape, leaving only the first main area 121 and the edge area 122 of the active layer 120. The difference between the thickness of the edge area 122 and the first main area 121 is small, which can effectively improve the uniformity of the overall thickness of the active layer 120, so that the thickness difference between the edge of the pole piece and the middle main part is small, and the thickness is more uniform.

[0054] Compared with the solutions in the related art, the embodiment of the present application makes the ratio of the minimum thickness of the edge area 122 of the active layer 120 to the thickness of the first main area 121 be 0.95 to 1.05, which can effectively reduce the thickness difference of the entire active layer 120, make the thickness of the active layer 120 on the current collector 110 more uniform, and effectively reduce the thickness difference between the middle main part and the edge of the pole piece, so that the thickness of the entire pole piece is more uniform. In this way, after the pole piece is wound or stacked, the accumulation of thickness difference can be effectively reduced, and the thickness difference between the middle main part and the edge of the battery cell can be effectively reduced. The content of the active layer 120 can be effectively increased, thereby effectively improving the energy density of the battery cell.

[0055] Continue to participate Figure 2 As shown, the thickness of the edge region 122 gradually decreases from the end of the edge region 122 close to the first main region 121 to the end of the edge region 122 away from the first main region 121. That is, the lowest thickness of the edge region 122 is the thickness of the end of the edge region 122 away from the first main region 121. Therefore, it can be understood that the ratio of the lowest thickness of the edge region 122 to the thickness of the first main region 121 is the ratio of the thickness of the end of the edge region 122 away from the first main region 121 to the thickness of the first main region 121.

[0056] The thickness of the edge region 122 at one end away from the first main region 121 is the smallest thickness of the entire active layer 120, and the thickness of the first main region 121 is the thickest thickness of the active layer 120, that is, the ratio between the smallest thickness of the active layer 120 and the thickest thickness of the active layer 120 is 0.95 to 1.05. This can effectively reduce the overall thickness difference of the active layer 120, effectively improve the uniformity of the overall thickness of the active layer 120, effectively improve the uniformity of the overall thickness of the pole piece 100, and effectively increase the content of the active layer 120, thereby effectively improving the energy density of the battery cell.

[0057] Among them, the ratio of the thickness of the highest point of the second main region 131 of the insulating layer 130 to the thickness of the highest point of the first main region 121 of the active layer 120 is 1:1 to 1:4. The thickness of the insulating layer 130 is relatively small compared to the thickness of the active layer 120, and the difference in thickness between the insulating layer 130 and the active layer 120 is also small, which can make the thickness of the material layer on the current collector more uniform. During the hot pressing and forming process of the electrode sheet, the depression at the electrode tab connection area of the battery cell can be reduced, making the stress on the whole battery cell more uniform, thereby effectively improving the adhesiveness at the edge of the electrode sheet and enhancing the overall structural stability of the battery cell.

[0058] Figure 4 It is a schematic structural diagram of a current collector provided by an embodiment of the present application.

[0059] See Figure 4 As shown, the current collector 110 may include a connected electrode region 111 and an electrode tab region 112. For example, the electrode tab region 112 may be cut out on the current collector 110 by means such as cutting. For example, after the insulating layer 130 is dot - set on the current collector 110, the electrode sheet 100 may be cut or trimmed to form the electrode tab region 112.

[0060] The active layer 120 may be located on the electrode region 111, and the second main region 131 of the insulating layer 130 may be located on the electrode tab region 112. Among them, the insulating layer 130 may slide down from the middle highest point to the surroundings. For example, the insulating layer 130 may be dropped onto the current collector 110 by means of dispensing. After the insulating layer 130 is dropped onto the current collector 110, the insulating layer 130 may extend around, and as the insulating layer 130 extends outward, the thickness of the insulating layer 130 will gradually decrease. The thickness of the middle part of the insulating layer 130 is relatively the thickest, and the thickest part is the second main region 131 of the insulating layer 130.

[0061] Among them, when the insulating layer 130 is set by means of dispensing, the insulating layer 130 may be dropped onto the electrode tab region 112 so that the second main region 131 of the insulating layer 130 falls on the electrode tab region. This can ensure the amount of the insulating layer 130 set on the electrode tab region 112, enabling the insulating layer 130 to effectively cover the burrs at the cut edge of the electrode tab region 112, thereby effectively preventing the burrs from piercing the separator and further causing problems such as battery short - circuit, and can effectively improve the safety of the battery.

[0062] Moreover, the second main region 131 of the insulating layer 130 is the thickest part of the insulating layer 130. The second main region 131 is located in the tab region 112, and its relatively thick thickness can increase the thickness at the edge of the electrode sheet 100. By making the difference in thickness between the edge region 122 of the electrode sheet 100 and the middle thickness of the electrode sheet 100 smaller, the overall thickness uniformity of the electrode sheet 100 can be effectively improved. In this way, after the electrode sheet 100 is wound or stacked, the accumulation of thickness differences can be effectively reduced, and the thickness difference between the middle main part and the edge of the battery cell can be effectively reduced. During the hot pressing and forming process of the electrode sheet 100, the depression at the tab region 112 where the battery cell is connected can be reduced, making the overall force on the battery cell more uniform, thereby effectively improving the adhesiveness at the edge of the electrode sheet 100 and enhancing the overall structural stability of the battery cell.

[0063] In the embodiment of the present application, the forming material of the insulating layer 130 can be any one of boehmite, alumina, or polyimide. The above materials all have good insulation properties, can effectively improve the insulation performance of the insulating layer 130, can effectively reduce or avoid the occurrence of short circuits in the battery, and thus effectively improve the safety of the battery.

[0064] Among them, continue to refer to Figure 2 As shown, the distance from the highest point of the second main region 131 to the edge region 122 can be a, where 0.2 mm ≤ a ≤ 1.5 mm. In other words, it can be understood that the dimension of the position of the dropping point of the insulating layer 130 from the edge region 122 of the active layer 120 is the above value.

[0065] By controlling the distance between the position of the dropping point of the insulating layer 130 and the edge region 122 of the active layer 120, during the spreading process of the insulating layer 130, the intersection between the insulating layer 130 and the edge of the active layer 120 can be made more reasonable. The gap between the insulating layer 130 and the active layer 120 can be effectively reduced, and the mutual fusion between the insulating layer 130 and the active layer 120 can be reduced or avoided.

[0066] This can prevent the gap between the insulating layer 130 and the active layer 120 from being too large, causing the negative electrode sheet to contact the current collector and resulting in a short circuit. It can also avoid excessive contact fusion between the insulating layer 130 and the active layer 120, which would cause the thickness of the fused part to be too high and make the thickness of the electrode sheet uneven.

[0067] Continue to refer to Figure 2 As shown, the distance from the highest point of the second main region 131 to the end of the insulating layer 130 away from the edge region 122 can be b, where 1.5 mm ≤ b ≤ 3 mm. That is, the dimension of the distance from the highest point of the insulating layer 130 to the end of the insulating layer 130 away from the edge region 122 is relatively small. This can reduce the proportion of the insulating layer 130 on the current collector, thereby increasing the proportion of the active layer 120 on the current collector and effectively improving the energy density of the battery.

[0068] Among them, the value of a can be less than the value of b. After the insulating layer 130 drips onto the tab area 112, the distance that the insulating layer 130 flows away from the active layer 120 is b, and the distance that the insulating layer 130 flows towards the active layer 120 is a. By making the value of a less than the value of b, that is, after the insulating layer 130 flows a certain distance towards the active layer 120 and contacts the active layer 120, the flow stops, while the insulating layer 130 continues to flow away from the active layer 120.

[0069] Among them, when the insulating layer 130 flows and encounters the obstruction of the active layer 120, the flow will stop. And as the insulating layer 130 continues to flow, the thickness of the end of the insulating layer 130 close to the active layer 120 will gradually increase. This can effectively reduce the thickness difference between the insulating layer 130 and the active layer 120, thereby effectively improving the uniformity and consistency of the overall thickness of the battery cell.

[0070] Continue to refer to Figure 2 As shown, the ratio of the distance a from the highest point of the insulating layer 130 to the edge area 122 to the length of the tab area 112 can be 0.1 - 0.3. This can increase the coverage size of the insulating layer 130 on the tab area 112. When the separator shrinks at high temperature in the battery, the negative electrode tab can be in contact with the insulating layer 130, which can prevent the negative electrode tab from contacting the tab area 112 and causing a short circuit, helping to improve the safety of the battery.

[0071] Continue to refer to Figure 2 As shown, the thickness of the highest point of the insulating layer 130 can be d3, and the thickness of the end of the edge area 122 close to the insulating layer 130 can be d2. The ratio between the value of d3 and the value of d2 can be 1:1 - 3:1. This can reduce the thickness difference between the insulating layer 130 and the active layer 120, effectively improve the flatness of the overall thickness of the battery cell, thereby improving the adhesiveness at the edge of the battery cell, and effectively improving the stability of the battery cell.

[0072] Continue to refer to Figure 2 As shown, there is a gap 140 between the insulating layer 130 and the edge area 122, and the width of the gap 140 is less than or equal to 0.5 mm. The size of the gap 140 is small, which can reduce or avoid the negative electrode tab area contacting the current collector 110 and causing a short circuit inside the battery, helping to improve the safety of the battery.

[0073] And / or, the ratio of the gap 140 to the width of the insulating layer 130 (that is, a + b) can be less than 0.3. By controlling the ratio relationship between the gap 140 and the width of the insulating layer 130, the size of the gap 140 can be controlled, and the size of the gap 140 can be effectively reduced. This can reduce or avoid the negative electrode tab area contacting the current collector 110 and causing a short circuit inside the battery, helping to improve the safety of the battery.

[0074] Among them, the gap 140 can be located in the pole piece area 111 or in the tab area 112. Due to the relatively long length of the pole piece 100, during the coating process of the active layer 120 on the current collector 110, the edge of the active layer 120 will shift to a certain extent, causing part of the edge of the active layer 120 to be located on the pole piece area 111 and part on the tab area 112, so that the corresponding gap 140 is located in the pole piece area 111 or the tab area 112.

[0075] An embodiment of the present application can also provide an electric core, which can include a first pole piece, a second pole piece and a separator. The first pole piece can be the pole piece 100 in any of the above scenarios. For example, the pole piece 100 can be a positive pole piece, and the second pole piece can be a negative pole piece 100. By making the electric core include the above-mentioned pole piece 100, the concave parts in the electric core can be effectively reduced, the uniformity of the overall thickness of the electric core can be effectively improved, the adhesiveness of the overall electric core can be enhanced, and thus the structural stability of the electric core can be effectively improved. Moreover, the energy density of the electric core can also be effectively increased.

[0076] Among them, along the direction from the pole piece area 111 to the tab area 112 of the first pole piece, the highest point of the insulating layer 130 exceeds the edge of the second pole piece. In other words, it can be understood that the highest point of the insulating layer 130 is located outside the negative pole piece. In this way, on the premise of satisfying the wrapping effect on the positive pole piece, the edge of the negative pole piece can be closer to the edge of the positive pole piece, effectively reducing the size difference between the negative pole piece and the positive pole piece, which helps to improve the overall energy density of the electric core.

[0077] An embodiment of the present application can also provide a battery, which can include the above-mentioned electric core. By making the battery include the above-mentioned electric core, the electric core has good flatness and structural stability, which can effectively improve the overall flatness and structural stability of the battery, helping to extend the service life of the battery. Moreover, it can also make the battery have a relatively high energy density, improving the battery's endurance time.

[0078] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model.

[0079] In the description of the present utility model, it should be understood that the terms "comprising", "having" and any variations thereof used herein are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily limit to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0080] Unless otherwise clearly specified and defined, terms such as "installed", "connected", "joined", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. In addition, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model and are not intended to limit them; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present utility model.

Claims

1. A pole piece, characterized in that: It includes a current collector, an active layer and an insulating layer located on the current collector; The active layer comprises a first main region and an edge region connected to each other, the insulating layer is arranged adjacent to the edge region of the active layer, the insulating layer comprises a second main region and a first side region adjacent to the active layer, and the thickness of the first side region of the insulating layer is less than the thickness of the second main region of the insulating layer; The ratio of the minimum thickness of the edge region to the thickness of the first main region is 0.95 to 1.05 。 2. The pole piece according to claim 1, characterized in that: The thickness of the edge region gradually decreases from an end of the edge region close to the first main region to an end of the edge region far from the first main region.

3. The pole piece according to claim 1 or 2, characterized in that: The ratio of the thickness of the highest point of the second main body region to the thickness of the highest point of the first main body region is 1:1 to 1:

4.

4. The pole piece according to claim 1 or 2, characterized in that: The current collector includes a connected pole piece region and a pole ear region; The active layer is located on the pole piece region, and the second main body region of the insulating layer is located on the pole lug region.

5. The pole piece according to claim 1 or 2, characterized in that: The distance from the highest point of the second main body region to the edge region is a, the distance from the highest point of the second main body region to the end of the insulating layer away from the edge region is b, and the value of a is less than or equal to the value of b; and / or, 0.2 mm ≤ said a ≤ 1.5 mm; And / or, 1.5mm≤b≤3mm.

6. The pole piece according to claim 4, characterized in that: The ratio of the distance a from the highest point of the second main body region to the edge region to the length of the tab region is 0.1 to 0.

3.

7. The pole piece according to claim 1 or 2, characterized in that: The ratio of the thickness of the highest point of the second main region to the thickness of the edge region close to one end of the insulating layer is 1:1 to 3:

1.

8. The pole piece according to claim 4, characterized in that: There is a gap between at least part of the insulating layer and the edge region, and a ratio of the gap to a width of the insulating layer is less than 0.3; And / or, the width of the gap is less than or equal to 0.5 mm.

9. The pole piece according to claim 8, characterized in that: The gap is located in the pole piece region or in the pole lug region.

10. A battery cell, characterized in that: It comprises a first pole piece, a second pole piece and a diaphragm, wherein the first pole piece is the pole piece described in any one of claims 1 to 9.

11. The battery cell according to claim 10, characterized in that: Along the direction from the pole piece region to the pole lug region of the first pole piece, the highest point of the insulating layer of the first pole piece exceeds the edge of the second pole piece.

12. A battery, characterized in that: Comprising the battery cell according to claim 10 or 11.

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