Pole piece, battery cell and battery

Abstract

The utility model relates to the technical field of batteries, in particular to a pole piece, a battery cell and a battery. The pole piece comprises a current collector, an active substance layer and an adhesive layer, the current collector is provided with a coating surface arranged along the thickness direction of the current collector, the active substance layer is arranged on the coating surface, the active substance layer is provided with a groove, and the adhesive layer covers the surface of the groove. The battery cell comprises the pole piece provided by the utility model. The battery comprises the battery cell provided by the utility model. According to the utility model, active material dust particles can be adhered by using the adhesive layer, so that the powder falling degree of the pole piece is reduced, and the use safety of the battery cell and the battery is ensured.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to an electrode, a cell, and a battery. Background Technology

[0002] With the rapid development of electronic products, users have increasingly higher requirements for lithium-ion batteries. The industry is developing laser drilling technology to build efficient lithium-ion transport channels. These channels can increase electrolyte retention capacity (i.e., the ability to retain electrolyte), which helps improve battery dynamics and achieve the coexistence of high energy density and fast charging technology.

[0003] The principle of laser drilling technology is to create grooves on the positive and negative electrodes by destroying some of the active material. These grooves serve as lithium-ion transport channels, increasing the battery's liquid retention capacity. However, the grooves formed by laser drilling contain broken active material in the middle and at the edges, which inevitably increases the amount of dust shedding from the electrodes. If this dust escapes throughout the electrodes, it can easily cause internal short circuits in the battery, worsening the voltage drop. Utility Model Content

[0004] The main purpose of this invention is to propose an electrode, a cell, and a battery, which aims to solve the technical problem that the grooves formed after laser drilling contain broken active materials that are damaged. This inevitably increases the amount of dust falling off the electrode. If the dust escapes everywhere inside the electrode, it can easily cause an internal short circuit in the battery, which will worsen the voltage drop of the battery.

[0005] To achieve the above objectives, this utility model proposes an electrode sheet, comprising:

[0006] A current collector having a coating surface disposed along its thickness direction;

[0007] An active material layer is disposed on the coating surface, and the active material layer is provided with grooves;

[0008] An adhesive layer that covers the surface of the groove.

[0009] In some embodiments, along the width direction of the current collector, the groove extends from one end of the current collector to the opposite end of the current collector.

[0010] In some embodiments, along the length direction of the current collector, one end of the adhesive layer is provided with a first extension segment in a direction away from the groove, and the other end of the adhesive layer is provided with a second extension segment in a direction away from the groove, the first extension segment and the second extension segment covering the surface of the active material layer.

[0011] In some embodiments, along the length direction of the current collector, the coating width D1 of the first extension section satisfies: 0.1mm≤D1≤0.8mm, and the coating width D2 of the second extension section satisfies: 0.1mm≤D2≤0.8mm.

[0012] In some embodiments, along the width direction of the current collector, the first extension and the second extension extend from one end of the current collector to the opposite end of the current collector.

[0013] In some embodiments, the active material layer has a plurality of grooves spaced apart along the length direction of the current collector, and the surface of the active material layer between two adjacent grooves is provided with the adhesive layer.

[0014] In some embodiments, the spacing L between two adjacent grooves satisfies: L > 1.5 mm, and the groove width D and groove depth H of each groove satisfy: D / H < 1.2, and the coating thickness H1 of the adhesive layer satisfies: 3 μm ≤ H1 ≤ 4 μm;

[0015] Alternatively, the spacing L between two adjacent grooves satisfies: L > 1.5 mm, and the groove width D and groove depth H of each groove satisfy: D / H ≥ 1.2, and the coating thickness H1 of the adhesive layer satisfies: 5 μm ≤ H1 ≤ 7 μm.

[0016] In some embodiments, the spacing L between two adjacent grooves satisfies: L≤1.5mm, and the groove width D and groove depth H of each groove satisfy: D / H<1.2, and the coating thickness H1 of the adhesive layer satisfies: 6um≤H1≤8um;

[0017] Alternatively, the spacing L between two adjacent grooves satisfies: L≤1.5mm, and the groove width D and groove depth H of each groove satisfy: D / H≥1.2, and the coating thickness H1 of the adhesive layer satisfies: 9um≤H1≤11um.

[0018] Correspondingly, this utility model also proposes a battery cell, comprising:

[0019] The electrode sheet described in any of the preceding claims includes a positive electrode sheet and a negative electrode sheet;

[0020] A separator is disposed between the positive electrode and the negative electrode, and the separator completely separates the positive electrode and the negative electrode.

[0021] Correspondingly, this utility model also proposes a battery, comprising:

[0022] The battery cell described in the above embodiments;

[0023] An aluminum-plastic film casing, wherein the battery cell is disposed within the aluminum-plastic film casing;

[0024] Adhesive tape is disposed between the battery cell and the aluminum-plastic film shell to bond the battery cell to the aluminum-plastic film shell.

[0025] Compared with the prior art, the beneficial effects of this utility model are:

[0026] In the technical solution of this utility model, because the adhesive layer has adhesive properties, after the groove is formed by laser drilling, the active material dust particles that were originally broken or about to fall off after rolling in the middle and edge areas of the groove will be firmly adhered to the adhesive layer. This prevents the active material dust particles from escaping within the electrode sheet, effectively reducing the problem of electrode powder shedding and preventing internal short circuits caused by direct contact between active material dust particles of different polarities. This is beneficial to improving the safety of the battery cell and achieving the goal of improving the K-value. The adhesive layer also enhances the electrode sheet's ability to absorb and retain electrolyte, improving the stability and safety of the battery during use and extending its lifespan. The adhesive layer also improves the buffering performance of the electrode sheet. During the needle penetration test, the adhesive layer buffers the penetrating force of the steel needle, hindering the needle and making the battery less likely to be punctured. This effectively improves the battery's pass rate during the needle penetration test, reduces the risk of internal short circuits during the test, and ensures safety during the test.

[0027] Using the aforementioned electrode plates in the battery cells, and in the batteries using the aforementioned battery cells, can reduce the risk of internal short circuits, avoid voltage drops, and ensure safe use. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0029] Figure 1 This is a front view of the structure of an electrode sheet provided in an embodiment of the present invention; wherein the adhesive layer is applied intermittently.

[0030] Figure 2 This is a top view of the electrode sheet provided in an embodiment of the present invention; wherein the adhesive layer is applied intermittently.

[0031] Figure 3 This is a front view of the electrode structure provided in another embodiment of the present invention; wherein the adhesive layer is applied in a continuous coating manner;

[0032] Figure 4 This is a top view of the electrode sheet provided in another embodiment of the present invention; wherein the adhesive layer is applied in a continuous coating manner;

[0033] Figure 5 This is a schematic diagram of the structural parameters of an electrode sheet provided in an embodiment of the present invention; wherein the adhesive layer is applied intermittently.

[0034] Explanation of icon numbers:

[0035] 10. Electrode;

[0036] 100. Current collector;

[0037] 110. Coated surface;

[0038] 200. Active substance layer;

[0039] 210. Groove;

[0040] 300, Adhesive layer;

[0041] 310. First extension; 320. Second extension.

[0042] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0043] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0044] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0045] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or," "and / or," or "and / or" throughout the text implies three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where A and B are simultaneously satisfied. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0046] With the rapid development of electronic products, users have increasingly higher requirements for lithium-ion batteries. The industry is developing laser drilling technology to build efficient lithium-ion transport channels. These channels can increase electrolyte retention capacity (i.e., the ability to retain electrolyte), which helps improve battery dynamics and achieve the coexistence of high energy density and fast charging technology.

[0047] The principle of laser drilling technology is to create grooves on the positive and negative electrodes by destroying some of the active material. These grooves serve as lithium-ion transport channels, increasing the battery's liquid retention capacity. However, the grooves formed after laser drilling contain broken active material in the middle and at the edges, which inevitably increases the amount of dust shedding from the electrodes. If this dust escapes throughout the electrodes, it can easily lead to internal short circuits in the battery, worsening the voltage drop (in this field, voltage drop is represented by the K-value, a physical quantity used to describe the battery's self-discharge rate).

[0048] Therefore, in order to solve the above problems, refer to Figures 1 to 4This utility model provides an electrode 10, which includes a current collector 100, an active material layer 200, and a binder layer 300. The current collector 100 can be a positive electrode current collector or a negative electrode current collector. In lithium-ion batteries, when the current collector 100 is a positive electrode current collector, materials such as aluminum foil can be used; when the current collector 100 is a negative electrode current collector, materials such as copper foil can be used. The current collector 100 has a coating surface 110 disposed along its thickness direction. For example, the current collector 100 can have a single-sided coating surface disposed along its thickness direction, or the current collector 100 can also have a double-sided coating surface disposed along its thickness direction. The active material layer 200 is disposed on the coating surface 110. When the current collector 100 is a positive electrode current collector, the active material layer 200 is a positive electrode active material layer, and can be lithium cobalt oxide, nickel-cobalt-manganese ternary composite material, lithium iron phosphate, lithium manganese oxide, and other novel materials. When the current collector 100 is the negative electrode current collector, the active material layer 200 is the negative electrode active material layer, which can be made of graphite, petroleum coke, carbon, silicon-based materials, and other novel materials. When the current collector 100 has a single-sided coating surface, the active material layer 200 is coated on one side only. When the current collector 100 has a double-sided coating surface, the active material layer 200 is coated on both sides, resulting in a higher energy density for the battery cell formed using this electrode 10. The active material layer 200 is provided with grooves 210. Grooves 210 can be formed on the active material layer 200 by laser drilling. For example, the grooves 210 can be square, circular, or strip-shaped; the shape, structure, and number of grooves 210 are not limited here. An adhesive layer 300 covers the surface of the grooves 210. The adhesive layer 300 can be PVDF (polyvinylidene fluoride), PMMA (polymethyl methacrylate), NMP (N-methylpyrrolidone), etc.

[0049] Specifically, in this embodiment, because the adhesive layer 300 has adhesive properties, after the groove 210 is formed by laser drilling, the active material dust particles that were originally broken or were about to fall off after rolling in the middle and edge areas of the groove 210 will be firmly adhered to the adhesive layer 300. This prevents the active material dust particles from escaping within the electrode 10, effectively reducing the problem of powder shedding from the electrode 10 and preventing internal short circuits caused by direct contact between active material dust particles of different polarities. This is beneficial to improving the safety of the battery cell and achieving the goal of improving the K-value. The adhesive layer 300 can also enhance the electrolyte absorption and retention capacity of the electrode 10, enhancing the stability and safety of the battery during use and extending its service life. The adhesive layer 300 can also improve the buffering performance of the electrode 10. When the battery is subjected to a nail penetration test, the adhesive layer 300 can buffer the penetrating force of the steel needle and act as an obstacle to the steel needle, making the battery less likely to be punctured by the steel needle. This can effectively improve the pass rate of the battery during the nail penetration test, reduce the risk of internal short circuit during the nail penetration test, and ensure the safety of the battery during the nail penetration test.

[0050] In some embodiments, refer to Figures 1 to 4 Along the width direction of the current collector 100, the groove 210 extends from one end of the current collector 100 to the opposite end of the current collector 100. For example, the groove 210 may extend from one end of the current collector 100 in a straight line to the opposite end of the current collector 100, or the groove 210 may extend from one end of the current collector 100 in a curve to the opposite end of the current collector 100, or the groove 210 may extend from one end of the current collector 100 in a broken line to the opposite end of the current collector 100.

[0051] Specifically, in this embodiment, compared to the discontinuous groove 210 or the dot-shaped groove 210, the above structure is advantageous in increasing the groove area of ​​the groove 210 in the active material layer 200, thereby facilitating the storage of more electrolyte within the groove 210 and improving the electrolyte absorption and retention capacity of the electrode 10. Simultaneously, since the length of the current collector 100 is larger than its width, compared to creating the groove 210 along the length of the current collector 100 in the active material layer 200, creating the groove 210 along the width of the current collector 100 ensures that sufficient active material is retained after grooving, avoiding excessive loss of active material.

[0052] In some embodiments, refer to Figure 1 and Figure 2Along the length of the current collector 100, one end of the adhesive layer 300 is provided with a first extension section 310 in the direction away from the groove 210, and the other end of the adhesive layer 300 is provided with a second extension section 320 in the direction away from the groove 210. The first extension section 310 and the second extension section 320 cover the surface of the active material layer 200.

[0053] Specifically, in this embodiment, since active material dust particles are easily generated on both sides of the groove 210 after the groove is opened by laser, the first extension section 310 and the second extension section 320 help to increase the contact area between the adhesive layer 300 and the side edge areas where active material dust particles are easily generated. Thus, the adhesive layer 300 can effectively bond the active material dust particles, reduce the degree of powder shedding from the electrode 10, and reduce the risk of internal short circuits in the electrode 10.

[0054] When the active material layer 200 has a plurality of grooves 210 spaced apart along the length of the current collector 100, the adhesive layer 300 forms an intermittent coating between two adjacent grooves 210. The above coating method helps to save the consumables of the adhesive layer 300 and reduce the production cost of the electrode 10.

[0055] In some embodiments, refer to Figure 5 Along the length direction of the current collector 100, the coating width D1 of the first extension 310 satisfies: 0.1mm ≤ D1 ≤ 0.8mm, and the coating width D2 of the second extension 320 satisfies: 0.1mm ≤ D2 ≤ 0.8mm. For example, the values ​​of D1 and D2 can be 0.1mm, 0.3mm, 0.5mm, 0.8mm, etc. Furthermore, along the width direction of the current collector 100, the first extension 310 and the second extension 320 extend from one end of the current collector 100 to the opposite end of the current collector 100.

[0056] Specifically, in this embodiment, corresponding to the structure of the groove 210, the coating width of the first extension section 310 and the second extension section 320 is set within the above-mentioned range. This ensures the contact area between the first extension section 310, the second extension section 320 and the active material dust particles, enabling the first extension section 310 and the second extension section 320 to effectively bond the active material dust particles. It also reduces the consumption of adhesive layer 300, thereby achieving the goal of cost reduction and efficiency improvement.

[0057] In some embodiments, refer to Figure 3 and Figure 4 The active material layer 200 has a plurality of grooves 210 spaced apart along the length of the current collector 100, and an adhesive layer 300 is provided on the surface of the active material layer 200 between two adjacent grooves 210.

[0058] Specifically, in this embodiment, the adhesive layer 300 is continuously coated between two adjacent grooves 210, meaning that the surface of the active material layer 200 is coated with the adhesive layer 300. During the needle penetration test on the battery, the position where the steel needle penetrates the battery is random. Since the surface of the active material layer 200 is coated with the adhesive layer 300, regardless of where the steel needle penetrates the battery, the adhesive layer 300 buffers the needle, increasing the resistance when the needle pierces the battery, making it difficult for the needle to penetrate the battery, thereby effectively ensuring the safety of the battery cell during the needle penetration test.

[0059] In some embodiments, refer to Figure 5 The spacing L between two adjacent grooves 210 satisfies: L > 1.5 mm, and the groove width D and groove depth H of each groove 210 satisfy: D / H < 1.2, and the coating thickness H1 of the adhesive layer 300 satisfies: 3 μm ≤ H1 ≤ 4 μm.

[0060] Specifically, in this embodiment, when each groove 210 is narrower and deeper (i.e., D / H < 1.2) and the distance between two adjacent grooves 210 is larger (i.e., L > 1.5 mm), most of the active material dust particles generated during laser drilling will be concentrated in the groove 210, and fewer active material dust particles will escape from the groove 210. Therefore, based on the principle of economy, the coating thickness of the adhesive layer 300 can be set slightly thinner.

[0061] In some embodiments, refer to Figure 5 The spacing L between two adjacent grooves 210 satisfies: L>1.5mm, and the groove width D and groove depth H of each groove 210 satisfy: D / H≥1.2, and the coating thickness H1 of the adhesive layer 300 satisfies: 5um≤H1≤7um.

[0062] Specifically, in this embodiment, when each groove 210 is relatively wide and shallow (i.e., D / H≥1.2), and the distance between two adjacent grooves 210 is relatively large (i.e., L>1.5mm), the active material dust particles generated during laser drilling may escape from the grooves 210. However, since the distance between two adjacent grooves 210 is relatively large and they do not affect each other, the coating thickness of the adhesive layer 300 can be set slightly larger than the coating thickness of the adhesive layer 300 in the above embodiment.

[0063] In some embodiments, refer to Figure 5 The spacing L between two adjacent grooves 210 satisfies: L≤1.5mm, and the groove width D and groove depth H of each groove 210 satisfy: D / H<1.2, and the coating thickness H1 of the adhesive layer 300 satisfies: 6um≤H1≤8um.

[0064] Specifically, in this embodiment, when each groove 210 is narrower and deeper (i.e., D / H < 1.2) and the distance between two adjacent grooves 210 is smaller (i.e., L ≤ 1.5 mm), most of the active material dust particles generated during laser drilling will be concentrated in the groove 210, and fewer active material dust particles will escape from the groove 210. However, since the distance between two adjacent grooves 210 is closer, based on the principle of effective adhesion, the coating thickness of the adhesive layer 300 can be set slightly larger than the coating thickness of the adhesive layer 300 in the above two embodiments.

[0065] In some embodiments, refer to Figure 5 The spacing L between two adjacent grooves 210 satisfies: L≤1.5mm, and the groove width D and groove depth H of each groove 210 satisfy: D / H≥1.2, and the coating thickness H1 of the adhesive layer 300 satisfies: 9um≤H1≤11um.

[0066] Specifically, in this embodiment, when each groove 210 is relatively wide and shallow (i.e., D / H≥1.2), and the distance between two adjacent grooves 210 is small (i.e., L≤1.5mm), the active material dust particles generated during laser drilling may escape from the grooves 210. Moreover, since the distance between two adjacent grooves 210 is relatively close, the coating thickness of the adhesive layer 300 can be set to be larger than the coating thickness of the adhesive layer 300 in the above three embodiments, so as to adsorb and adhere more active material dust particles.

[0067] Referring to Table 1, several sets of experiments were conducted to compare the design parameters of the groove 210 and the coating thickness of the adhesive layer 300. The adhesive layer 300 was PDVF with a solid content of 2-6%, and the coating method was continuous coating as an example.

[0068] Case 1:

[0069] The groove 210 has a groove spacing L = 1.6 mm, a groove width D = 21 mm ± 0.2, a groove depth H = 24 mm, D / H < 1.2, and a PVDF adhesive coating thickness H1 of 0 μm.

[0070] Case 2 (Best Implementation):

[0071] The groove 210 has a groove spacing L = 1.6 mm, groove width D = 21 mm ± 0.2, groove depth H = 24 mm, D / H < 1.2, and PVDF adhesive coating thickness H1 is 3 μm.

[0072] Case 3:

[0073] The groove 210 has a groove spacing L = 1.6 mm, groove width D = 21 mm ± 0.2, groove depth H = 24 mm, D / H > 1.2, and PVDF adhesive coating thickness H1 is 3 μm.

[0074] Case 4 (Best Implementation):

[0075] The groove 210 has a groove spacing L = 1.6 mm, a groove width D = 21 mm ± 0.2, a groove depth H = 24 mm, a D / H ratio > 1.2, and a PVDF adhesive coating thickness H1 of 6 μm.

[0076] Case 5 (Best Implementation):

[0077] The groove 210 has a groove spacing L = 1.2 mm, groove width D = 21 mm ± 0.2, groove depth H = 24 mm, D / H < 1.2, and PVDF adhesive coating thickness H1 is 6 μm.

[0078] Case 6:

[0079] The groove 210 has a groove spacing L = 1.2 mm, groove width D = 30 mm ± 0.2, groove depth H = 24 mm, D / H > 1.2, and PVDF adhesive coating thickness H1 is 7 μm.

[0080] Case 7 (Best Implementation):

[0081] The groove 210 has a groove spacing L = 1.2 mm, groove width D = 30 mm ± 0.2, groove depth H = 24 mm, D / H > 1.2, and PVDF adhesive coating thickness H1 is 10 μm.

[0082] Case 8:

[0083] The groove 210 has a groove spacing L = 1.2 mm, a groove width D = 30 mm ± 0.2, a groove depth H = 24 mm, D / H > 1.2, and a ceramic coating thickness H1 of 10 μm.

[0084] In the above case, the electrode sheet 10 coated with adhesive layer 300 is wound to obtain a bare cell, and then encapsulated, injected with electrolyte, formed, and sealed in sequence to obtain the desired finished cell.

[0085] The mean K-value of the battery cell and the results of the safety test (needle penetration test) are as follows:

[0086]

[0087] Table 1

[0088] Table 1 shows that Cases 2, 4, 5 and 7 are the optimal embodiments, that is, the coating thickness of the adhesive layer 300 and the design parameters of the groove 210 are most matched at this time.

[0089] Correspondingly, another embodiment of this utility model also provides a battery cell, which includes the electrode 10 in any of the above embodiments. The battery cell also includes a separator. The electrode 10 includes a positive electrode and a negative electrode, and the separator is disposed between the positive and negative electrode, completely separating the positive and negative electrode to prevent direct contact between the positive and negative electrode, thus preventing a short circuit within the battery cell and ensuring the safety of the battery cell. This battery cell can be a wound battery cell or a stacked battery cell.

[0090] Correspondingly, another embodiment of this utility model also provides a battery, which includes the battery cell described in the above embodiment. The battery also includes an aluminum-plastic film casing and adhesive tape. The battery cell is disposed inside the aluminum-plastic film casing, and the adhesive tape is disposed between the battery cell and the aluminum-plastic film casing to adhere the battery cell to the aluminum-plastic film casing, preventing the battery cell from shaking inside the aluminum-plastic film casing and ensuring the safety of the battery in use.

[0091] Specifically, in this embodiment, the use of the electrode 10 and the battery using the electrode 10 can reduce the risk of internal short circuits, avoid voltage drop, and ensure safety in use.

[0092] Thanks to the improvements to the electrode 10 described above, the cell and battery of this embodiment have the same technical effects as the electrode 10 described above, which will not be repeated here.

[0093] It should be noted that other contents of the electrode 10, the cell and the battery disclosed in this utility model can be found in the prior art, and will not be repeated here.

[0094] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural transformations made based on the inventive concept of this utility model and the contents of this utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this utility model.

Claims

1. An electrode, characterized in that, include: A current collector having a coating surface disposed along its thickness direction; An active material layer is disposed on the coating surface, and the active material layer is provided with grooves; An adhesive layer that covers the surface of the groove.

2. The electrode sheet according to claim 1, characterized in that, Along the width direction of the current collector, the groove extends from one end of the current collector to the opposite end of the current collector.

3. The electrode sheet according to claim 2, characterized in that, Along the length of the current collector, one end of the adhesive layer is provided with a first extension section in the direction away from the groove, and the other end of the adhesive layer is provided with a second extension section in the direction away from the groove. The first extension section and the second extension section cover the surface of the active material layer.

4. The electrode sheet according to claim 3, characterized in that, Along the length direction of the current collector, the coating width D1 of the first extension section satisfies: 0.1mm≤D1≤0.8mm, and the coating width D2 of the second extension section satisfies: 0.1mm≤D2≤0.8mm.

5. The electrode sheet according to claim 3, characterized in that, Along the width direction of the current collector, the first extension segment and the second extension segment extend from one end of the current collector to the opposite end of the current collector.

6. The electrode sheet according to claim 2, characterized in that, The active material layer has a plurality of grooves spaced apart along the length of the current collector, and the surface of the active material layer between two adjacent grooves is provided with the adhesive layer.

7. The electrode sheet according to claim 6, characterized in that, The spacing L between two adjacent grooves satisfies: L > 1.5 mm, and the groove width D and groove depth H of each groove satisfy: D / H < 1.2, and the coating thickness H1 of the adhesive layer satisfies: 3 μm ≤ H1 ≤ 4 μm; Alternatively, the spacing L between two adjacent grooves satisfies: L > 1.5 mm, and the groove width D and groove depth H of each groove satisfy: D / H ≥ 1.2, and the coating thickness H1 of the adhesive layer satisfies: 5 μm ≤ H1 ≤ 7 μm.

8. The electrode sheet according to claim 6, characterized in that, The spacing L between two adjacent grooves satisfies: L≤1.5mm, and the groove width D and groove depth H of each groove satisfy: D / H<1.2, and the coating thickness H1 of the adhesive layer satisfies: 6um≤H1≤8um; Alternatively, the spacing L between two adjacent grooves satisfies: L≤1.5mm, and the groove width D and groove depth H of each groove satisfy: D / H≥1.2, and the coating thickness H1 of the adhesive layer satisfies: 9um≤H1≤11um.

9. A battery cell, characterized in that, include: The electrode sheet according to any one of claims 1 to 8, wherein the electrode sheet comprises a positive electrode sheet and a negative electrode sheet; A separator is disposed between the positive electrode and the negative electrode, and the separator completely separates the positive electrode and the negative electrode.

10. A battery, characterized in that, include: The battery cell according to claim 9; An aluminum-plastic film casing, wherein the battery cell is disposed within the aluminum-plastic film casing; Adhesive tape is disposed between the battery cell and the aluminum-plastic film shell to bond the battery cell to the aluminum-plastic film shell.

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