Pole piece and battery cell

Abstract

The utility model discloses a pole piece and a battery cell. The pole piece comprises: a current collector having a first surface and a second surface opposite to the first surface; the first safety coatings are respectively arranged on the first surface and the second surface; the first safety coating is arranged on the first surface, the second safety coating is arranged on the first surface, and the second safety coating is in local lap joint with the first safety coating arranged on the first surface. The pole piece disclosed by the utility model can improve the safety performance of the battery.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to electrode sheets and battery cells. Background Technology

[0002] Lithium-ion batteries have gained widespread market favor due to their high energy density, long cycle life, and environmental friendliness, and have achieved significant development in recent years. With the continuous improvement of battery performance requirements, especially the pursuit of energy density, the improvement of positive and negative electrode materials for lithium-ion batteries has played a crucial role in increasing battery energy density.

[0003] However, the contribution of improved positive and negative electrode materials to increasing battery energy density is gradually decreasing, and safety issues become more prominent as battery energy density increases. Increased battery energy density may increase safety risks under conditions such as overcharging, over-discharging, or thermal runaway, posing a greater challenge to battery safety and reliability. In traditional cell winding structures, the positive current collector is typically used as the outermost layer of the core. For example, in this case, when the cell is in a high state of charge (high SOC) and suffers puncture damage, the positive current collector is directly exposed, and the aluminum foil of the electrode sheet is prone to direct contact with the negative electrode active material, increasing the risk of a short circuit inside the cell. This short circuit can rapidly cause battery overheating, or even lead to smoke or fire, thus posing a safety hazard.

[0004] In related technologies, it is known that electrodes with a first safety coating and a second safety coating are used to improve the efficiency of passing the needle penetration test. However, due to coating precision issues, the first and second safety coatings often cannot be tightly bonded, which may result in gaps between them. This can lead to the first and second safety coatings not completely covering the current collector, causing a short circuit inside the cell and posing a safety hazard. Therefore, designing a new electrode that can improve the safety performance of batteries has become an urgent problem to be solved in the development of lithium-ion battery technology. Utility Model Content

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes an electrode that can improve the safety performance of a battery.

[0006] This application also proposes a battery cell.

[0007] The electrode sheet according to an embodiment of the first aspect of the present invention includes:

[0008] A current collector having a first surface and a second surface opposite to the first surface;

[0009] A first safety coating is respectively disposed on the first surface and the second surface;

[0010] A second safety coating is disposed on the first surface, and the second safety coating partially overlaps with the first safety coating disposed on the first surface.

[0011] The electrode sheet according to the first aspect of the present invention has at least the following beneficial effects: it can improve the safety performance of the battery.

[0012] In this application, a first safety coating is provided on two opposing surfaces of the current collector. A second safety coating is also provided on the first surface of the current collector, overlapping the first safety coating to cover one end of the first safety coating. Therefore, when the first and second safety coatings are applied to the current collector, gaps between the first and second safety coatings will not occur due to coating precision issues. For example, if the electrode is a positive electrode, the overlapping of the second and first safety coatings in this application avoids gaps, preventing the positive current collector from being exposed and causing the negative electrode active material to directly contact the positive current collector through the gap, thus preventing a short circuit and improving battery safety.

[0013] According to some embodiments of the present invention, an active material layer is also included. The first safety coating disposed on the first surface includes a third surface away from the current collector, and the first safety coating disposed on the second surface includes a fourth surface away from the current collector. The active material layer is disposed on the third surface and the fourth surface respectively, wherein the active material layer disposed on the third surface partially overlaps the second safety coating.

[0014] According to some embodiments of the present invention, the length of the current collector is L1, the length of the first safety coating disposed on the first surface is L2, the length of the second safety coating is L3, and 6mm ≥ L2 + L3 - L1 > 0.

[0015] According to some embodiments of this utility model, the length of the active material layer is L4, 6mm ≥ L4-L2>0.

[0016] According to some embodiments of the present invention, the second safety coating includes a main body and an overlapping part, the main body and the overlapping part are connected, the main body is disposed on the first surface, and the overlapping part overlaps with the first safety coating disposed on the first surface;

[0017] The thickness of the first safety coating is H1, and the thickness of the main body is H2, where H2 > H1.

[0018] According to some embodiments of the present invention, the second safety coating includes a main body and an overlapping part, and the first safety coating includes a body part and an overlapping groove, wherein the overlapping part overlaps the overlapping groove;

[0019] The thickness of the body portion is H1, and the thickness of the main body portion is H2.

[0020] The thickness of the lap groove is h1, and the thickness of the lap portion is h2.

[0021] h1+h2≥H1=H2.

[0022] According to some embodiments of this utility model, H2≤h1+h2

[0023] According to some embodiments of the present invention, the first safety coating is provided with a reserved groove, the length of the reserved groove is A, 30mm≥A≥15mm, and the width of the reserved groove is B, 25mm≥B≥8mm.

[0024] According to some embodiments of the present invention, the active material layer is provided with a welding groove, the length of the welding groove is a, the width of the welding groove is b, 8mm≥Aa≥0, 8mm≥Bb≥0.

[0025] The battery cell according to an embodiment of the second aspect of the present invention includes the electrode sheets described in any of the preceding claims.

[0026] The battery cell according to the second aspect of this utility model has at least the following beneficial effects: it can improve the safety performance of the battery. The electrode of this application has a first safety coating on each of the two opposite surfaces of the current collector, and a second safety coating is further provided on the first surface of the current collector. The second safety coating overlaps the first safety coating to cover one end of the first safety coating. Therefore, when the first and second safety coatings are applied to the current collector, gaps between the first and second safety coatings will not occur due to coating precision issues. For example, if the electrode is a positive electrode, the method of overlapping the second and first safety coatings in this application can avoid gaps, preventing the positive current collector from being exposed and causing the negative electrode active material to directly contact the positive current collector through the gap, thus creating a short circuit and improving battery safety. Therefore, the battery cell with the electrode of this application can also improve battery safety performance.

[0027] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0028] ​The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0029] Figure 1 This is a schematic diagram of one embodiment of the electrode sheet of this utility model.

[0030] Figure 2 This is a schematic diagram of the first embodiment of the electrode.

[0031] Figure 3 for Figure 2 Enlarged view of point A in the middle.

[0032] Figure 4 This is a schematic diagram of a second embodiment of the electrode.

[0033] Figure label:

[0034] Current collector 100; first surface 101; second surface 102; first safety coating 200; third surface 201; fourth surface 202; reserved groove 203; body part 210; overlapping groove 220; second safety coating 300; main body part 310; overlapping part 320; active material layer 400; welding groove 401; thinning area 402; electrode tab 500. Detailed Implementation

[0035] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0036] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0037] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0038] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0039] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0040] As the energy density of lithium-ion batteries continues to increase, the contribution of improved positive and negative electrode materials to battery energy density is gradually decreasing. This is because increasing battery energy density depends not only on the materials themselves but also on multiple factors such as battery design, manufacturing processes, and battery management systems. Furthermore, with increasing battery energy density, safety issues become more prominent. Increased battery energy density may increase safety risks under conditions such as overcharging, over-discharging, or thermal runaway, posing a greater challenge to battery safety and reliability.

[0041] In traditional battery cell winding structures, the positive current collector is typically used as the outermost layer of the core. For example, at a high state of charge (high SOC), if the cell suffers puncture damage, the positive current collector is directly exposed, and the aluminum foil of the electrode can easily come into direct contact with the negative electrode active material, increasing the risk of a short circuit inside the cell. This short circuit can rapidly cause the battery to overheat, or even smoke or catch fire, posing a safety hazard. Therefore, to improve battery safety, it is necessary to consider improving the cell design to reduce the possibility of short circuits under extreme conditions.

[0042] In related technologies, to improve battery safety performance, several methods have been developed to enhance puncture resistance by applying safety coatings. For example, by applying a first and second safety coating to the electrode, the battery's efficiency in passing a nail penetration test can be improved. However, due to coating precision issues, these two safety coatings may not be tightly bonded, resulting in gaps between them and failing to completely cover the current collector. This allows active materials with opposite polarity to the current collector to come into direct contact with it, increasing the risk of internal short circuits within the cell and posing a safety hazard.

[0043] Therefore, in order to improve the safety performance of batteries, a new type of electrode is needed. This electrode can tightly connect the first safety coating and the second safety coating to avoid gaps between them, thereby completely covering the current collector and preventing direct contact between the positive current collector and the negative active material (this application uses the positive electrode as an example, but the electrode can also be a negative electrode. When the electrode is a negative electrode, this is to prevent direct contact between the negative current collector and the positive active material) and thus prevent internal short circuits in the battery, thereby improving the battery's safety performance.

[0044] Reference Figures 1 to 4 Mainly refer to Figure 1 An electrode sheet according to an embodiment of the first aspect of the present invention includes a current collector 100, a first safety coating 200, and a second safety coating 300. The current collector 100 has a first surface 101 and a second surface 102 opposite to the first surface 101. The first safety coating 200 is disposed on the first surface 101 and the second surface 102, respectively. The second safety coating 300 is disposed on the first surface 101, and the second safety coating 300 partially overlaps with the first safety coating 200 disposed on the first surface 101.

[0045] The electrode sheet according to the embodiment of the first aspect of this utility model has at least the following beneficial effects: it can improve the safety performance of the battery. In this application, a first safety coating 200 is respectively provided on two opposite surfaces of the current collector 100. A second safety coating 300 is also provided on the first surface 101 of the current collector 100. The second safety coating 300 overlaps the first safety coating 200 to cover one end of the first safety coating 200. Thus, when the first safety coating 200 and the second safety coating 300 are coated on the current collector 100, there will be no gap between the first safety coating 200 and the second safety coating 300 due to coating precision issues. By adopting the method of the second safety coating 300 overlapping the first safety coating 200, gaps can be avoided between the first safety coating 200 and the second safety coating 300, thereby avoiding the risk of short circuit caused by the negative electrode active material directly contacting the positive electrode current collector 100 through the gap due to exposure of the positive electrode current collector 100, thus improving the safety of the battery.

[0046] According to some embodiments of the present invention, an active material layer 400 is also included. The first safety coating 200 disposed on the first surface 101 includes a third surface 201 away from the current collector 100, and the first safety coating 200 disposed on the second surface 102 includes a fourth surface 202 away from the current collector 100. The active material layer 400 is disposed on the third surface 201 and the fourth surface 202 respectively, wherein the active material layer 400 disposed on the third surface 201 partially overlaps with the second safety coating 300. Specifically, in this application, the active material layer 400 is disposed on the surfaces of the first safety coating 200 away from the current collector 100 (i.e., the third surface 201 of one first safety coating 200 and the fourth surface 202 of the other first safety coating 200), while the second safety coating 300 does not have an active material layer 400 disposed on it.

[0047] The first safety coating 200 mainly comprises inorganic fillers, conductive agents, and adhesives. The adhesive achieves strong adhesion between the first safety coating 200 and the positive electrode current collector 100, protecting the aluminum foil (current collector 100) during mechanical safety testing and preventing direct contact between the aluminum foil and the negative electrode active material, thus improving the cell's safety. The conductive agent enables the first safety coating 200 to conduct electricity, facilitating the connection between the positive electrode current collector 100 and the positive electrode active material layer 400, allowing electrons to effectively transfer from the positive electrode current collector 100 to the positive electrode active material layer 400.

[0048] The second safety coating 300 mainly includes inorganic fillers and binders. The binder in the second coating enables strong adhesion between the second safety coating 300 and the positive electrode current collector 100, protecting the aluminum foil and completely covering it to prevent the aluminum foil from being exposed and coming into direct contact with the negative electrode active material during the cell's mechanical safety test, thus preventing the battery's safety performance from failing.

[0049] On the other hand, the active material layer 400 disposed on the third surface 201 partially overlaps with the second safety coating 300. This is to prevent areas between the first safety coating 200 and the second safety coating 300 from being uncovered by the active material layer 400. Specifically, when the active material layer 400 is applied, because the first safety coating 200 and the second safety coating 300 are similar in color, it is impossible to accurately identify the overlap 320 between them. In other words, if the active material layer 400 is only applied to the first safety coating 200, tiny gaps will inevitably appear at the overlap between the active material layer 400 and the second safety coating 300. Therefore, the active material layer 400 cannot completely cover the conductive first safety coating 200, posing a risk of short circuit due to exposure of the first safety coating 200. Therefore, in this application, by partially overlapping the active material layer 400 with the second safety coating 300, the active material layer 400 can completely cover the first safety coating 200 and partially cover the second safety coating 300, ensuring that there are no gaps between the first safety coating 200 and the second safety coating 300, and between the second safety coating 300 and the active material layer 400, thereby improving the safety performance of the electrode sheet, the subsequently wound cell, and the finished battery.

[0050] According to some embodiments of this utility model, the length of the current collector 100 is L1, the length of the first safety coating 200 disposed on the first surface 101 is L2, and the length of the second safety coating 300 is L3, where 6mm ≥ L2 + L3 - L1 > 0. As can be seen from the above, by overlapping the first safety coating 200 with the second safety coating 300, a tight connection between the first safety coating 200 and the second safety coating 300 can be achieved, preventing gaps that could expose the current collector 100 and create safety hazards. Specifically, the sum of the lengths of the first safety coating 200 and the second safety coating 300 should be greater than the length of the current collector 100 to form a structure where the second safety coating 300 overlaps the first safety coating 200. However, the length by which the second safety coating 300 overlaps the first safety coating 200 should not be too long, as long as it ensures a tight connection between the first safety coating 200 and the second safety coating 300 without gaps between them. If the length of the second safety coating 300 at the overlap portion 320 is too long, it will lead to a decrease in the energy density of the electrode, resulting in a decline in battery performance, and it will also be detrimental to improving material utilization. Therefore, by way of example, in this application, the sum of the lengths of the first safety coating 200 and the second safety coating 300 minus the length of the current collector 100 should be less than or equal to 6 mm, specifically 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, etc.

[0051] According to some embodiments of this utility model, the length of the active material layer 400 disposed on the first surface 101 is L4, where 6mm ≥ L4 - L2 ≥ 0. By partially overlapping the active material layer 400 with the second safety coating 300, the active material layer 400 can completely cover the first safety coating 200 and partially cover the second safety coating 300, ensuring that there are no gaps between the first safety coating 200 and the second safety coating 300, and between the second safety coating 300 and the active material layer 400, thereby improving the safety performance of the electrode sheet, the subsequently wound cell, and the finished battery. Specifically, the length of the active material layer 400 disposed on the third surface 201 should be greater than or equal to the length of the first safety coating 200, so as to form a structure in which the active material layer 400 partially overlaps the second safety coating 300. However, the length of the active material layer 400 overlapping the second safety coating 300 should not be too long, as long as it can ensure that the active material layer 400 and the second safety coating 300 can be tightly connected without any gaps between them. If the length of the active material layer 400 at the overlapping portion 320 is too long, it will lead to a waste of some active material, which is not conducive to improving material utilization. Therefore, by way of example, in this application, the length of the active material layer 400 minus the length of the first safety coating 200 should be less than or equal to 6 mm, specifically 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, etc.

[0052] According to some embodiments of the present invention, the second safety coating 300 includes a main body 310 and an overlapping portion 320, which are connected. The main body 310 is disposed on the first surface 101, and the overlapping portion 320 overlaps with the first safety coating 200 disposed on the first surface 101. The thickness of the first safety coating 200 is H1, and the thickness of the main body 310 is H2, where H2 ≥ H1. The thickness H2 of the main body 310 can be greater than the thickness H1 of the first safety coating 200, for example, referring to... Figure 1 The overlapping portion 320 of the second safety coating 300 overlaps the third surface 201 of the first safety coating 200. The thickness of the first safety coating 200 is H1 at both the overlapping and non-overlapping locations. This ensures that the overlapping portion 320 has sufficient thickness to guarantee a tight connection between the first safety coating 200 and the second safety coating 300, thus ensuring the safety of the battery cell, while also guaranteeing the insulation effect of the main body 310. Alternatively, the thickness H2 of the main body 310 can be equal to the thickness H1 of the first safety coating 200, meaning that only the overlapping portion 320 extends from the main body 310 to overlap the first safety coating 200, ensuring a tight connection between the first and second safety coatings 300.

[0053] Reference Figure 3According to some embodiments of the present invention, the second safety coating 300 includes a main body 310 and an overlapping portion 320, and the first safety coating 200 includes a main body 210 and an overlapping groove 220, wherein the overlapping portion 320 overlaps the overlapping groove 220. The thickness of the main body 210 is H1, the thickness of the main body 310 is H2, the thickness of the overlapping groove 220 is h1, and the thickness of the overlapping portion 320 is h2, where h1 + h2 ≥ H1 = H2. (Refer to...) Figure 2 In addition to the second safety coating 300 including an overlapping portion 320 that directly overlaps the first safety coating 200, an overlapping groove 220 can also be provided in the first safety coating 200. The overlapping portion 320 and the overlapping groove 220 cooperate with each other. After the overlapping portion 320 and the overlapping groove 220 overlap, the sum of the thickness h2 of the overlapping portion 320 and the thickness h1 of the overlapping groove 220 is equal to the thickness H2 of the main body portion 310 of the second safety coating 300, which is equal to the thickness H1 of the main body portion 210 of the first safety coating 200. Therefore, by having the overlapping portion 320 overlap the overlapping groove 220, gaps can be avoided between the first safety coating 200 and the second safety coating 300, thereby preventing the positive electrode current collector 100 from being exposed and causing the negative electrode active material to directly contact the positive electrode current collector 100 through the gap, resulting in a short circuit and improving battery safety.

[0054] According to some embodiments of this utility model, H2 ≤ h1 + h2 < H1 + H2. Specifically, by setting the sum of the thickness h2 of the overlapping portion 320 and the thickness h1 of the overlapping groove 220 to be greater than or equal to the thickness H2 of the main body portion 310, sufficient thickness of the overlapping portion 320 is ensured to guarantee the safety of the battery cell. Furthermore, by setting the sum of the thickness h2 of the overlapping portion 320 and the thickness h1 of the overlapping groove 220 to be less than the sum of the thickness H1 of the main body portion 210 and the thickness H2 of the main body portion 310, excessive overall thickness of the electrode sheet at the overlapping point can be avoided, preventing electrode sheet breakage during subsequent rolling processes.

[0055] Reference Figure 1 , Figure 4According to some embodiments of this utility model, the first safety coating 200 is provided with a reserved groove 203. The length of the reserved groove 203 is A, 30mm ≥ A ≥ 15mm, and the width of the reserved groove 203 is B, 25mm ≥ B ≥ 8mm. The reserved groove 203 is located at the edge of the electrode sheet and at the first safety coating 200 or the second safety coating 300. The reserved groove 203 can reserve sufficient space for welding the tab 500, facilitating subsequent welding of the tab 500. The length and width of the reserved groove 203 cannot be too large, otherwise the area of ​​the positive electrode active material layer 400 on the electrode sheet will be reduced, affecting the energy density of the cell. The length and width of the reserved groove 203 cannot be too small, because the welding of the tab 500 is achieved by equipment fluctuation, which can easily cause the tab 500 to be welded to the positive electrode active layer, thus affecting the welding accuracy. In this application, as an example, the length A of the reserved groove 203 ranges from 15mm to 30mm, specifically 15mm, 18mm, 20mm, 25mm, 28mm, 30mm, etc. As an example, the width B of the reserved groove 203 ranges from 8mm to 25mm, specifically 8mm, 12mm, 15mm, 18mm, 25mm, etc.

[0056] According to some embodiments of this utility model, the active material layer 400 is provided with a welding groove 401, the length of the welding groove 401 is a, the width of the welding groove 401 is b, 8mm≥Aa≥0, 8mm≥Bb≥0. Specifically, the size of the welding groove 401 is smaller than the size of the reserved groove 203, referring to... Figure 1 The active material layers 400 on both sides of the welding groove 401 extend beyond the reserved groove 203, forming a welding area at the extended active material portion. If the active material layer 400 extends beyond the reserved groove 203 by more than 8 mm, the weld size will be too small, making it easy to weld the tab 500 into the positive electrode active layer area. If the active material layer 400 extends beyond the reserved groove 203 by too small, the weld size will be too large, resulting in low active material content and reduced battery energy density. Therefore, the dimensions of the reserved groove 203 in both the length and width directions are larger than the dimensions of the welding groove 401. In this application, exemplarily, the difference ranges from 0 to 8 mm, specifically 2 mm, 4 mm, 6 mm, 8 mm, etc.

[0057] A thinning region 402 is provided on the side of the active material layer 400 on the third surface 201 near the second safety coating 300. The length of the thinning region 402 is W, where W ≥ 15 mm. The maximum thickness of the electrode sheet in the thinning region 402 is H. max The minimum thickness of the electrode is H. min H max -h≤3um,H min-h≥-7um. When the thickness of the 402 thinning zone is too thick, overpressure is likely to occur during rolling, and the electrode sheet is prone to breakage. When the thickness of the 402 thinning zone is too small, the cell has poor adhesion during hot pressing, lithium-ion transport is difficult, and lithium plating is likely to occur during the cell cycle.

[0058] The battery cell according to an embodiment of the second aspect of the present invention includes the electrode sheets described in any of the preceding claims.

[0059] The battery cell according to the second aspect of this utility model has at least the following beneficial effects: it can improve the safety performance of the battery. The electrode sheet of this application has a first safety coating 200 respectively disposed on two opposite surfaces of the current collector 100. A second safety coating 300 is also disposed on the first surface 101 of the current collector 100. The second safety coating 300 overlaps the first safety coating 200 to cover one end of the first safety coating 200. Therefore, when the first safety coating 200 and the second safety coating 300 are coated on the current collector 100, gaps between the first safety coating 200 and the second safety coating 300 will not occur due to coating precision issues. For example, if the electrode sheet is a positive electrode sheet, the method of overlapping the second safety coating 300 with the first safety coating 200 in this application can avoid the formation of gaps, preventing the positive current collector 100 from being exposed and causing the negative electrode active material to directly contact the positive current collector 100 through the gap, thus avoiding the risk of a short circuit and improving battery safety. Therefore, a cell with the electrode of this application can also improve the safety performance of the battery.

[0060] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. An electrode, characterized in that, include: A current collector having a first surface and a second surface opposite to the first surface; A first safety coating is respectively disposed on the first surface and the second surface; A second safety coating is disposed on the first surface, and the second safety coating partially overlaps with the first safety coating disposed on the first surface; The active material layer, the first safety coating disposed on the first surface includes a third surface away from the current collector, the first safety coating disposed on the second surface includes a fourth surface away from the current collector, the active material layer is disposed on the third surface and the fourth surface respectively, wherein the active material layer disposed on the third surface partially overlaps the second safety coating.

2. The electrode sheet according to claim 1, characterized in that, The length of the current collector is L1, the length of the first safety coating disposed on the first surface is L2, the length of the second safety coating is L3, and 6mm ≥ L2 + L3 - L1 > 0.

3. The electrode sheet according to claim 2, characterized in that, The length of the active material layer is L4, 6mm ≥ L4 - L2 ≥ 0.

4. The electrode sheet according to claim 1, characterized in that, The second safety coating includes a main body and an overlapping portion, the main body and the overlapping portion are connected, the main body is disposed on the first surface, and the overlapping portion overlaps with the first safety coating disposed on the first surface; The thickness of the first safety coating is H1, and the thickness of the main body is H2, where H2 ≥ H1.

5. The electrode sheet according to claim 1, characterized in that, The second safety coating includes a main body and an overlapping portion, and the first safety coating includes a main body and an overlapping groove, wherein the overlapping portion overlaps the overlapping groove; The thickness of the body portion is H1, and the thickness of the main body portion is H2. The thickness of the lap groove is h1, and the thickness of the lap portion is h2. h1+h2≥H1=H2.

6. The electrode sheet according to claim 5, characterized in that, H2≤h1+h2<H1+H2.

7. The electrode sheet according to claim 1, characterized in that, The first safety coating has a reserved groove, the length of which is A, 30mm≥A≥15mm, and the width of which is B, 25mm≥B≥8mm.

8. The electrode sheet according to claim 7, characterized in that, The active material layer is provided with a welding groove, the length of the welding groove is a, the width of the welding groove is b, 8mm≥Aa≥0, 8mm≥Bb≥0.

9. A battery cell, characterized in that, The electrode includes any one of claims 1 to 8.

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