Negative pole piece, battery and electric device

Abstract

The utility model discloses a negative pole piece, a battery and an electric device, and relates to the technical field of batteries. The negative pole piece comprises a current collector and a negative active material layer arranged on the surface of the current collector, a bonding part is arranged between the current collector and the negative active material layer, and the bonding part covers a local area of the current collector and is bonded with the negative active material layer and the current collector. The bonding part is arranged between the current collector and the negative electrode active material layer, so that the bonding strength between the current collector and the negative electrode active material layer is improved, and the risks of powder falling in the subsequent hot pressing process and film stripping in the subsequent charging and discharging process are reduced. Moreover, the bonding part only covers the local area of the current collector, so that the partial area of the current collector is still kept to be directly connected with the negative active material layer, and the conductivity of the negative pole piece can be ensured. The battery provided by the utility model comprises the negative pole piece, so that the negative pole piece is not easy to demould, and the performance is stable.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a negative electrode plate, a battery and an electrical device. Background Art

[0002] At present, the negative electrode plates of many secondary batteries (such as sodium ion batteries) mainly use hard carbon as the negative electrode active material, which is carried on the current collector. During the manufacturing process, the negative electrode active material slurry is directly coated on the foil current collector. The adhesion between the negative electrode active material and the current collector is poor, and the peeling force of the negative electrode active material layer is low. After the battery cell is hot-pressed, the inner ring bend will fall off, which can easily cause a short circuit in the battery; even worse, the plate will peel off after charging and discharging, the capacity will decay quickly, and the cycle performance will be poor. Utility Model Content

[0003] The purpose of the present application is to provide a negative electrode plate, a battery and an electrical device, wherein the bonding strength between the negative electrode active material layer of the negative electrode plate and the current collector is high, thereby reducing the risk of powder loss and film peeling.

[0004] The embodiment of the present application is implemented as follows:

[0005] In a first aspect, the present application provides a negative electrode plate, comprising a current collector and a negative electrode active material layer arranged on at least one surface of the current collector, at least one bonding portion is arranged between the current collector and the negative electrode active material layer, the bonding portion covers a local area of ​​the current collector and adheres the negative electrode active material layer and the current collector.

[0006] In an optional embodiment, the material of the bonding portion is PVDF glue.

[0007] In an optional embodiment, there are multiple bonding portions, and the multiple bonding portions are non-continuously distributed on the surface of the current collector.

[0008] In an optional embodiment, a plurality of bonding portions are distributed discontinuously on the surface of the current collector in the form of dot-shaped protrusions, and a size of the bonding portion in a direction perpendicular to the current collector is 0.4 μm to 2 μm.

[0009] In an optional embodiment, the area of ​​the current collector covered by a single bonding portion is 3×10 -4 cm 2 ~3×10 -2 cm 2 .

[0010] In an optional embodiment, the bonding portion is a strip film structure, a plurality of strip film structures are spaced apart along the width direction of the current collector, or a plurality of strip film structures are spaced apart along the length direction of the current collector; and the thickness of the bonding portion is 0.4 μm to 2 μm.

[0011] In an optional embodiment, the area of ​​the current collector covered by the adhesive portion accounts for 10% to 50% of the projected area of ​​the negative electrode active material layer on the current collector.

[0012] In an optional embodiment, the negative electrode sheet is used to be wound to form a winding core, the winding core has a flat area and a bending area, the negative electrode sheet has flat areas and bending areas alternately arranged along its length direction, the flat area corresponds to the flat area of ​​the winding core, the bending area corresponds to the bending area of ​​the winding core, and the unit surface density of the bonding portion in the bending area is greater than the unit surface density of the bonding portion in the flat area.

[0013] In a second aspect, the present application provides a battery comprising the negative electrode sheet of any one of the aforementioned embodiments.

[0014] In a third aspect, the present application provides an electrical device, comprising the battery of the second aspect.

[0015] The beneficial effects of the embodiments of the present application are:

[0016] The negative electrode sheet provided in the embodiment of the present application includes a current collector and a negative electrode active material layer that are stacked, and an adhesive portion is provided between the current collector and the negative electrode active material layer, the adhesive portion covers a local area of ​​the current collector, and adheres the negative electrode active material layer and the current collector. By providing an adhesive portion between the current collector and the negative electrode active material layer, the bonding strength between the current collector and the negative electrode active material layer is improved, and the risk of powder loss in the subsequent hot pressing process and demolding during the subsequent charging and discharging process is reduced. In addition, since the adhesive portion only covers a local area of ​​the current collector, a part of the current collector remains directly connected to the negative electrode active material layer, which can ensure the conductivity of the negative electrode sheet. It can be seen that the negative electrode sheet provided in the embodiment of the present application can take into account both the product yield and cycle performance of the battery.

[0017] The battery provided in the embodiment of the present application includes the above-mentioned negative electrode plate, so the negative electrode plate is not prone to film peeling and has stable performance.

[0018] The power-consuming device provided in the embodiment of the present application includes the above-mentioned battery, and its power supply is stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 This is a schematic diagram of a negative electrode sheet in one embodiment of the present application;

[0021] Figure 2 A cross-sectional view of a negative electrode sheet in one embodiment of the present application;

[0022] Figure 3 This is a schematic diagram of a negative electrode sheet in another embodiment of the present application;

[0023] Figure 4 A cross-sectional view of a negative electrode sheet in another embodiment of the present application;

[0024] Figure 5 This is a schematic diagram of a negative electrode sheet in another embodiment of the present application;

[0025] Figure 6 This is a schematic diagram of two winding cores in one embodiment of the present application;

[0026] Figure 7 This is a cross-sectional view of a winding core in one embodiment of the present application.

[0027] Icon: 010-winding core; 011-flat area; 012-bending area; 100-negative electrode sheet; 101-flat area; 102-bending area; 110-current collector; 120-negative electrode active material layer; 130-adhesive part; 140-negative electrode ear; 200-positive electrode sheet; 210-positive electrode ear; 300-diaphragm. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0030] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0031] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0032] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0033] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0034] At present, the negative electrode sheets of many secondary batteries are prone to powder loss and film stripping, which affects the product yield and battery performance. Taking sodium ion batteries as an example, their negative electrode sheets mainly use hard carbon as the negative electrode active material, and aluminum foil is used as the current collector to carry the negative electrode active material. In the manufacturing process of sodium ion batteries, the negative electrode coating is to directly coat the slurry on the aluminum foil current collector. The adhesion between the negative electrode active material hard carbon and the current collector is poor, and the peeling force of the negative electrode active material layer is low. After the battery cell is hot-pressed, the inner ring bend loses powder, which can easily cause a short circuit in the battery; even worse, after charging and discharging, the electrode sheet is stripped, the capacity decays quickly, and the cycle performance is poor. The improvement method in the related art is to add a larger proportion of binder during the homogenization process. The defect of this method is that the binder content in the negative electrode slurry is too high, and the proportion of negative electrode active material will be reduced, resulting in a lower energy density of the battery. Moreover, even if the amount of binder added is high, the peeling force of the negative electrode active material layer is still very small, the battery cell after hot pressing loses powder seriously, and the battery cell after cycling is prone to film stripping.

[0035] To this end, the present invention provides a negative electrode sheet, which increases the bonding force between the current collector and the negative electrode active material layer by adding an adhesive portion between the current collector and the negative electrode active material layer. In addition, the present invention also provides a battery, including the above-mentioned negative electrode sheet.

[0036] Figure 1 This is a schematic diagram of the distribution of the bonding portion 130 on the current collector 110 in one embodiment of the present application; Figure 2 FIG. 1 is a cross-sectional view of a negative electrode plate 100 in one embodiment of the present application. Figure 1 and Figure 2 As shown, the negative electrode plate 100 includes a current collector 110 and a negative electrode active material layer 120 disposed on at least one surface of the current collector 110. At least one bonding portion 130 is disposed between the current collector 110 and the negative electrode active material layer 120, and the bonding portion 130 covers a local area of ​​the current collector 110 and adheres the negative electrode active material layer 120 and the current collector 110. By providing the bonding portion 130, the bonding strength between the current collector 110 and the negative electrode active material layer 120 can be improved, thereby reducing the powder loss after hot pressing and the film peeling after charging and discharging. The bonding portion 130 only covers a local area of ​​the current collector 110, so that the negative electrode active material layer 120 and the current collector 110 are still in direct contact, thereby ensuring the conductivity of the negative electrode plate 100. Figure 1 and Figure 2 In the embodiment, the negative electrode active material layer 120 is disposed on one surface of the current collector 110 as an example for description. In other embodiments, the negative electrode active material layer 120 may be disposed on two opposite surfaces of the current collector 110 .

[0037] Optionally, the material of the bonding portion 130 is PVDF glue; specifically, the PVDF glue can be a mixture of PVDF (polyvinylidene fluoride) and polyacrylonitrile glue. In other embodiments, the PVDF glue can also include a conductive agent to improve the conductivity of the bonding portion 130 and even the entire negative electrode plate 100.

[0038] In the embodiment of the present application, the bonding portion 130 between the current collector 110 and the negative electrode active material layer 120 may be a whole, that is, continuous; or a plurality of bonding portions 130 may be provided between the current collector 110 and the negative electrode active material layer 120, and the plurality of bonding portions 130 are non-continuously distributed on the surface of the current collector 110. Figure 1 and Figure 2 In the illustrated embodiment, there are a plurality of bonding portions 130 between the current collector 110 and the negative electrode active material layer 120 , and the plurality of bonding portions 130 are distributed discontinuously.

[0039] like Figure 1 and Figure 2As shown, a plurality of bonding portions 130 are non-continuously distributed on the surface of the current collector 110 in the form of dot-shaped protrusions. The bonding portions 130 in the shape of dot-shaped protrusions can be formed by coating PVDF slurry at multiple points on the current collector 110 before coating the negative electrode active material layer 120. The PVDF slurry can also be sprayed on the current collector 110 by spraying, and the atomized and dispersed droplets fall on the current collector 110, and after curing, the bonding portions 130 in the shape of dot-shaped protrusions are formed. It can be understood that if a single bonding portion 130 is required to have a larger size, a multi-point coating method can be used, and if a smaller and more evenly distributed bonding portion 130 is required, a discretely distributed bonding portion 130 can be formed by spraying.

[0040] Figure 1 , Figure 2 In the embodiment, the bonding portion 130 is formed by spraying. It should be understood that in order to clearly show the discretely distributed bonding portions 130, a single bonding portion 130 is enlarged in the figure, and the ratio of a single bonding portion 130 to the current collector 110 in the figure does not represent the actual ratio of the bonding portion 130 to the current collector 110.

[0041] Optionally, the size (ie, height) of the bonding portion 130 in a direction perpendicular to the current collector 110 is 0.4 μm to 2 μm. When the discrete bonding portions 130 are formed by spraying, the size of a single bonding portion 130 can be controlled by the spray head structure, spraying rate, and the like.

[0042] Optionally, when the bonding portion 130 is formed by spraying, the PVDF slurry falls on the current collector 110 in the form of particles, the particle size range of the particles is 0.5 μm to 5 μm, and the surface area of ​​the particles can be 0.196×10 -8 cm 2 ~0.196×10 -6 cm 2 .

[0043] Optionally, the area of ​​the current collector 110 covered by a single bonding portion 130 is 3×10 -4 cm 2 ~3×10 -2 cm 2, the gap between adjacent bonding parts 130 can be 5mm to 50mm. Optionally, the area of ​​the current collector 110 covered by the bonding part 130 accounts for 10% to 50% of the projected area of ​​the negative electrode active material layer 120 on the current collector 110. Specifically in this embodiment, the area of ​​the current collector 110 is equal to that of the negative electrode active material layer 120, and the projected area of ​​the negative electrode active material layer 120 on the current collector 110 is equal to the area of ​​the current collector 110 or the negative electrode active material layer 120. Therefore, in this embodiment, the area of ​​the current collector 110 covered by the discretely distributed multiple bonding parts 130 accounts for 10% to 50% of the surface area of ​​the current collector 110. It should be understood that the larger the coverage area of ​​the bonding part 130, the better the bonding performance, but the conductivity may decrease; the smaller the coverage area of ​​the bonding part 130, the better the conductivity, but the bonding stability will decrease.

[0044] Figure 3 This is a schematic diagram of the distribution of the bonding portion 130 on the current collector 110 in another embodiment of the present application; Figure 4 It is a cross-sectional view of a negative electrode sheet 100 in another embodiment of the present application; Figure 5 FIG. 1 is a schematic diagram showing the distribution of the bonding portion 130 on the current collector 110 in another embodiment of the present application. Figures 3 to 5 As shown, the bonding part 130 may be a film structure, and the two opposite surfaces of the bonding part 130 in the thickness direction are respectively bonded to the current collector 110 and the negative electrode active material layer 120. The bonding part 130 of the film structure may be formed by coating (which may be roll coating or dip coating). In the coating method of forming the bonding part 130, the thickness of the bonding part 130 may be selected to be 0.4 μm to 2 μm.

[0045] Specifically in Figure 3 , Figure 5 In the illustrated embodiment, the bonding portion 130 is a strip film structure, and a plurality of bonding portions 130 of strip film structures are arranged at intervals along the width direction of the current collector 110. It should be understood that in other optional embodiments, a plurality of bonding portions 130 of strip film structures may be arranged at intervals along the length direction of the current collector 110.

[0046] Figure 6 This is a schematic diagram of two winding cores 010 in one embodiment of the present application; Figure 7 FIG. 1 is a cross-sectional view of a winding core 010 in one embodiment of the present application. Figure 6 and Figure 7 As shown, in the embodiment of the present application, the negative electrode sheet 100 is used to be wound to form a winding core 010 (specifically, it is wound together with the positive electrode sheet 200 and the separator 300), and the winding core 010 has a flat area 011 and a bending area 012. The negative electrode sheet 100 has flat areas 101 and bending areas 102 alternately arranged along its length direction, and the flat area 101 corresponds to the flat area 011 of the winding core 010, and the bending area 102 corresponds to the bending area 012 of the winding core 010. Figure 3 In the embodiment, any adhesive portion 130 is distributed in the flat region 101 or the bent region 102 of the negative electrode sheet 100, that is, the same adhesive portion 130 does not span the flat region 101 and the bent region 102. Figure 5 In the illustrated embodiment, at least part of the bonding portion 130 has a relatively long dimension, spanning the flat region 101 and the bent region 102 along the length direction of the negative electrode sheet 100. Figure 5 As shown, the two adhesive portions 130 extend along the length direction of the negative electrode sheet 100 , and have a length substantially the same as that of the negative electrode sheet 100 , spanning across a plurality of flat regions 101 and bent regions 102 .

[0047] like Figure 1 , Figure 3 and Figure 5 As shown, the unit surface density of the bonding portion 130 in the bending region 102 is greater than the unit surface density of the bonding portion 130 in the flat region 101. In other words, the area ratio occupied by the bonding portion 130 in the bending region 102 is greater than the area ratio occupied by the bonding portion 130 in the flat region 101. Since the negative electrode sheet 100 in the bending region 102 is prone to powder loss and film release in the subsequent hot pressing process, more bonding portions 130 are arranged in the bending region 102 in the embodiment of the present application to improve the bonding strength between the current collector 110 and the negative active material layer 120 of the negative electrode sheet 100 in the bending region 102, and improve the problem of powder loss and film release.

[0048] exist Figure 1 , Figure 3 , Figure 5 In the illustrated embodiment, a plurality of mutually spaced adhesive portions 130 are provided on one surface of the current collector 110, in which case the plurality of adhesive portions 130 are non-continuously distributed on the current collector 110. In other optional embodiments, the adhesive portions 130 may be continuously distributed on the surface of the current collector 110, that is, the adhesive portion 130 is a continuous whole. In this case, a plurality of avoidance openings may be provided on the adhesive portion 130 so that the current collector 110 is connected to the negative electrode active material through the avoidance openings to ensure conductivity. The area ratio of the adhesive portion 130 covering the current collector 110 is adjusted by adjusting the size and density of the avoidance openings. Optionally, the adhesive portion 130 may also be distributed on the current collector 110 in a mesh structure.

[0049] Optionally, the PVDF slurry used for spraying or coating to form the bonding portion 130 may include PVDF, water and polyacrylonitrile glue. In the PVDF slurry, the PVDF ratio is 2% to 15% by mass; the polyacrylonitrile glue ratio is 8% to 20% and the water ratio is 65% to 90%. Among them, water is removed as a solvent in the subsequent baking. In the PVDF slurry used for spraying, PVDF accounts for 0.5% to 2% of the total solid content of the final negative electrode slurry (used to form the negative electrode active material layer 120). In other optional embodiments, in order to improve conductivity, a conductive agent can also be added to the PVDF slurry. In this case, the bonding portion 130 finally formed contains a conductive agent.

[0050] When manufacturing the negative electrode sheet 100 of the embodiment of the present application, firstly, PVDF slurry is applied to the surface of the current collector 110 by coating or spraying, and the PVDF slurry is dried in an oven at a temperature of 70 to 100° C. Then, the negative electrode slurry is applied to the current collector 110 coated with PVDF glue by transfer or extrusion coating. When the negative electrode slurry is baked, the high temperature generated by the oven can make the PVDF glue work, so that the negative electrode active material layer 120 formed by the negative electrode slurry is tightly combined with the current collector 110 to improve the peeling force of the negative electrode active material layer 120.

[0051] In the case where the adhesive portion 130 is not provided, the peeling force of the negative electrode active material layer 120 is 0.05-0.15 N. In the embodiment of the present application, when the particle size of the sprayed PVDF slurry particles ranges from 0.5 μm to 5 μm and the surface area is 0.196×10 - 8 cm 2 ~0.196×10 -6 cm 2 In the case of , the peeling force of the negative active material layer 120 on the negative electrode sheet 100 is 0.2-0.4N. When the thickness of the coated PVDF slurry is 0.4-2μm, the peeling force of the negative active material layer 120 on the negative electrode sheet 100 is 0.25-0.5N. Preferably, when the thickness of the sprayed PVDF glue is 0.4-2μm, the peeling force is 0.2-0.5N.

[0052] The following table shows the test results of peeling force and resistance of the adhesive portion 130 formed into a film structure by coating at different thicknesses and coverage area ratios.

[0053]

[0054] It can be seen from the test results that pre-setting the adhesive part 130 made of PVDF glue on the current collector 110 can significantly increase the peeling force of the negative electrode sheet 100, and the resistance of the negative electrode sheet 100 will also increase. If the adhesive part 130 covers too small an area of ​​the current collector 110 and the thickness is too thin, the effect of improving the peeling force of the negative electrode sheet 100 is not obvious. If the adhesive part 130 covers too large an area of ​​the current collector 110 and the thickness is too thick, the peeling force of the negative electrode sheet 100 is significantly improved, but the resistance also increases. Optionally, when the adhesive part 130 covers 30% to 40% of the area of ​​the current collector 110 and the thickness is 0.6μm to 1μm, the membrane peeling force is 0.23 to 0.5N, the membrane resistance is 3.2 to 18.7mΩ, and the negative electrode sheet 100 reaches a better performance.

[0055] The present application also provides a battery, which includes the negative electrode sheet 100 provided in the above embodiment of the present application. Figure 6 As shown, the battery further includes a positive electrode sheet 200 and a separator 300. The positive electrode sheet 200 and the negative electrode sheet 100 are wound together to form a winding core 010, and the separator 300 separates the positive electrode sheet 200 from the negative electrode sheet 100. Further, a negative electrode tab 140 is provided on the negative electrode sheet 100, and a positive electrode tab 210 is also provided on the positive electrode sheet 200; optionally, the negative electrode tab 140 and the positive electrode tab 210 are located on the same side of the entire winding core 010 in the extension direction of the winding axis. Optionally, the battery further includes a shell and an electrolyte contained in the shell, and the winding core 010 is immersed in the electrolyte.

[0056] The embodiment of the present application also provides an electric device (not shown in the figure), including the battery provided in the above embodiment of the present application. The electric device can be any device that needs to be driven by electricity, such as an electric car.

[0057] In summary, the negative electrode sheet 100 provided in the embodiment of the present application includes a current collector 110 and a negative electrode active material layer 120 disposed on at least one surface of the current collector 110, and an adhesive portion 130 is disposed between the current collector 110 and the negative electrode active material layer 120, and the adhesive portion 130 covers a local area of ​​the current collector 110 and adheres the negative electrode active material layer 120 and the current collector 110. By arranging the adhesive portion 130 between the current collector 110 and the negative electrode active material layer 120, the bonding strength between the current collector 110 and the negative electrode active material layer 120 is improved, and the risk of powder falling in the subsequent hot pressing process and the risk of film removal in the subsequent charging and discharging process is reduced. In addition, since the adhesive portion 130 only covers a local area of ​​the current collector 110, a part of the current collector 110 remains directly connected to the negative electrode active material layer 120, which can ensure the conductivity of the negative electrode sheet 100. It can be seen that the negative electrode plate 100 provided in the embodiment of the present application can take into account both the product yield and the cycle performance of the battery.

[0058] The battery provided in the embodiment of the present application includes the above-mentioned negative electrode plate 100, so the negative electrode plate 100 is not prone to film peeling and has stable performance.

[0059] The power-consuming device provided in the embodiment of the present application includes the above-mentioned battery, and its power supply is stable.

[0060] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A negative electrode plate, characterized in that: The invention comprises a current collector (110) and a negative electrode active material layer (120) arranged on at least one surface of the current collector, wherein at least one bonding portion (130) is arranged between the current collector (110) and the negative electrode active material layer (120), and the bonding portion (130) covers a local area of ​​the current collector (110) and adheres the negative electrode active material layer (120) and the current collector (110).

2. The negative electrode sheet according to claim 1, characterized in that: The material of the bonding portion (130) is PVDF glue.

3. The negative electrode sheet according to claim 1, characterized in that: There are a plurality of bonding portions (130), and the plurality of bonding portions (130) are distributed discontinuously on the surface of the current collector (110).

4. The negative electrode sheet according to claim 3, characterized in that: The plurality of bonding portions (130) are distributed discontinuously on the surface of the current collector (110) in the form of dot-shaped protrusions, and the size of the bonding portion (130) in a direction perpendicular to the current collector (110) is 0.4 μm to 2 μm.

5. The negative electrode sheet according to claim 4, characterized in that: The area covered by a single adhesive portion (130) on the current collector is 3×10 -4 cm 2 ~3×10 -2 cm 2 .

6. The negative electrode sheet according to claim 1, characterized in that: The bonding part (130) is a strip-shaped film structure, and a plurality of the strip-shaped film structures are arranged at intervals along the width direction of the current collector (110), or a plurality of the strip-shaped film structures are arranged at intervals along the length direction of the current collector (110); the thickness of the bonding part (130) is 0.4 μm to 2 μm.

7. The negative electrode sheet according to claim 1, characterized in that: The area of ​​the current collector (110) covered by the bonding portion (130) accounts for 10% to 50% of the projected area of ​​the negative electrode active material layer (120) on the current collector (110).

8. The negative electrode sheet according to claim 1, characterized in that: The negative electrode sheet (100) is used to be wound to form a winding core (010), the winding core (010) having a flat region (011) and a bending region (012), the negative electrode sheet having a flat region (101) and a bending region (102) alternately arranged along its length direction, the flat region (101) corresponding to the flat region (011) of the winding core (010), the bending region (102) corresponding to the bending region (012) of the winding core (010), and the unit surface density of the bonding portion (130) in the bending region (102) is greater than the unit surface density of the bonding portion (130) in the flat region (101).

9. A battery, characterized in that: A negative electrode sheet (100) comprising any one of claims 1 to 8.

10. An electrical device, characterized in that: A battery comprising the battery of claim 9.

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