Pole piece and battery and electronic device comprising same

Abstract

The invention provides a pole piece and a battery and an electronic device comprising the same. The pole piece comprises a current collector, an active substance layer and a reinforcing layer, at least one surface of the current collector comprises an active material layer coating region and an active material layer non-coating region which are adjacently arranged along a first direction; wherein the active material layer is coated on the active material layer coating area; the reinforcing layer is coated on at least part of the uncoated area of the active material layer; in the first direction, the width of the uncoated area of the active material layer is W1mm, the width of the reinforcing layer is W2mm, and W1 / W2 is larger than or equal to 2.5 and smaller than or equal to 7.5. According to the pole piece, the battery comprising the pole piece and the electronic device comprising the pole piece, wrinkles and folds of the uncoated area of the active material layer can be reduced, and the safety performance of the battery is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of secondary batteries, and in particular to a pole piece and a battery and an electronic device comprising the pole piece. Background Art

[0002] In recent years, with the rapid development of mobile electronic devices and the booming rise of new energy vehicles, the market has placed higher demands on the energy density, cycle life, and fast charging performance of lithium-ion batteries. Among the various materials that make up lithium-ion batteries, aluminum foil and copper foil are widely used as current collectors for the positive and negative electrodes. Among them, the thickness of aluminum foil and copper foil is relatively thin, and the bending stiffness of the foil itself is extremely low. After die-cutting, the tabs are easily bent, wrinkled, and folded due to gravity, vibration, and winding centrifugal force. Because copper foil is generally thinner than aluminum foil, problems such as tab bending and wrinkling are likely to be significantly aggravated, affecting the production consistency of the stacking and winding processes, and even affecting the charge and discharge performance and safety performance of the finished battery cell. Summary of the Invention

[0003] The present invention provides a pole piece and a battery and an electronic device including the pole piece. The reinforcing layer can provide a better supporting effect and can improve the safety performance of the battery while reducing the requirements of wrinkles and folds in the uncoated area of the active material layer.

[0004] To solve the above technical problems, the present invention is achieved through the following technical solutions.

[0005] The present invention provides a pole piece, comprising a current collector, an active material layer and a reinforcement layer;

[0006] At least one side of the current collector includes an active material layer coating area and an active material layer uncoated area adjacent to each other along a first direction;

[0007] The active material layer is coated on the active material layer coating area; the reinforcing layer is coated on at least part of the active material layer uncoated area; along the first direction, the width of the active material layer uncoated area is W1 mm, and the width of the reinforcing layer is W2 mm, satisfying 2.5≤W1 / W2≤7.5.

[0008] In one embodiment of the present invention, along the first direction, there is a preset distance G mm between the active material layer and the reinforcement layer, which satisfies 22≤W1 / G≤400.

[0009] In one embodiment of the present invention, the preset spacing is 0.1 mm-1.1 mm.

[0010] In one embodiment of the present invention, along the first direction, the width of the active material layer is W3 mm, satisfying 3≤W3 / W1≤11.

[0011] In one embodiment of the present invention, the ratio of the thickness of the reinforcement layer to the thickness of the current collector is 1-6; or,

[0012] The thickness of the current collector is 4 μm-5.5 μm.

[0013] In one embodiment of the present invention, the grayscale value of the enhancement layer is 0-110.

[0014] In one embodiment of the present invention, the electrode piece further includes a pole tab, and part of the active material layer covers at least part of the surface of the pole tab along the first direction; or, a transition zone is provided between the pole tab and the active material layer coating area, and the reinforcement layer is located at part of the transition zone and part of the pole tab surface.

[0015] In one embodiment of the present invention, the tab further includes a plurality of reinforcing ribs, and the reinforcing ribs are stamped by the tab, and the reinforcing ribs are arranged in at least one of a point shape, a strip shape, a wave shape or a broken line shape, and the ratio of the width of the maximum overlapping position of the reinforcing ribs and the reinforcing layer to the width of the reinforcing layer is 0.1-1.

[0016] In one embodiment of the present invention, the active material layer is provided on both sides of the current collector, and the electrode is a negative electrode.

[0017] The present invention also provides a battery, comprising:

[0018] A shell having an upper opening;

[0019] an electrode assembly, placed into the housing through the upper opening; and

[0020] a cover plate assembly, closing the upper end opening;

[0021] In which, the electrode assembly is formed by stacking the positive electrode sheet, the separator and the negative electrode sheet and then winding or laminating them, and the negative electrode sheet adopts the electrode sheet described above; along the first direction, the electrode assembly includes a main body and an uncoated area of the active material layer, and the uncoated area of the active material layer includes a bending portion and a connecting portion, the connecting portion is fixedly connected to the cover plate assembly, and the bending portion is connected between the main body and the connecting portion; the reinforcement layer covers at least a partial area of the bending portion.

[0022] In one embodiment of the present invention, the electrode assembly is covered with a first tape, which is arranged on the side of the uncoated area of the active material layer facing away from the cover plate assembly. The first tape includes a first adhesive area, a second adhesive area, and a non-adhesive area between the first adhesive area and the second adhesive area. The first adhesive area covers the main body, and the second adhesive area covers the connecting part. In the thickness direction of the electrode assembly, the orthographic projection of the reinforcement layer is completely located in the non-adhesive area.

[0023] The present invention also provides an electronic device comprising the battery described above.

[0024] In summary, the electrode provided by the present invention and the battery and electronic device including the same can enable the reinforcing layer to provide better support when the width of the uncoated area of the active material layer is large, thereby avoiding wrinkles, folds, etc. in the uncoated area of the active material layer. It can also avoid the reinforcing layer from being too wide and occupying the welding area of the uncoated area of the active material layer. It can ensure the size of the welding area of the uncoated area of the active material layer and improve the safety performance of the battery. At the same time, when the electrode is assembled into a battery, because the uncoated area of the active material layer will be bent, the problem of interpolation can also be avoided, thereby avoiding related failures such as short circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 Schematic diagram of a pole piece in one embodiment.

[0027] Figure 2 For the Figure 1 Cross-sectional view of the pole piece in the AA direction.

[0028] Figure 3 Schematic diagram of the tab on the pole piece in one embodiment.

[0029] Figure 4 Schematic diagram of the pole tabs and reinforcing ribs on a pole piece in one embodiment.

[0030] Figure 5 Schematic diagram of the tab on the electrode sheet in another embodiment.

[0031] Figure 6 Schematic diagram of the pole tabs and reinforcing ribs on a pole piece in another embodiment.

[0032] Figure 7 Schematic diagram of a battery in one embodiment.

[0033] Figure 8 Schematic diagram of an electrode assembly in one embodiment.

[0034] Figure 9 Schematic diagram of an electrode assembly in another embodiment.

[0035] Figure 10 Schematic diagram of a positive electrode plate in one embodiment.

[0036] Figure 11 Schematic diagram of a positive electrode tab on a positive electrode sheet in one embodiment.

[0037] Figure 12 Schematic diagram of the positive electrode tab on the positive electrode sheet in another embodiment.

[0038] Figure 13 Schematic diagram of a portion of an electrode assembly in one embodiment.

[0039] Description of labels:

[0040] 10. Housing; 11. Cover assembly; 12. First pole; 13. Second pole; 14. Explosion-proof valve; 15. Liquid injection hole; 20. Electrode assembly; 100. Pole piece; 101. Active material layer coating area; 102. Active material layer uncoated area; 110. Current collector; 120. Active material layer; 130. Reinforcement layer; 140. Tab; 150. Reinforcement rib; 160. Transition zone; 2 00. Positive electrode sheet; 210. Positive electrode current collector; 220. Positive electrode active material layer; 230. Positive electrode tab area; 240. Positive electrode tab; 241. Connection area; 1. Main body; 111. Connection part; 112. Bending part; 1112. Adapter; 30. First adhesive tape; 31. First adhesive area; 32. Non-adhesive area; 33. Second adhesive area; 300. Diaphragm; 40. Second adhesive tape. DETAILED DESCRIPTION

[0041] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0042] It should be understood that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so that people familiar with this technology can understand and read them. They are not used to limit the conditions for the implementation of this solution, so they have no technical significance. Any modification of the structure, change in the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed in this solution without affecting the efficacy and purpose of this solution. At the same time, the terms such as "upper", "lower", "left", "right", "middle", "under", "below", "first", "second" and "one" quoted in this specification are only for the convenience of description and are not used to limit the scope of the implementation of this solution. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of this solution without substantially changing the technical content.

[0043] The technical solutions of the present invention are further described in detail below with reference to the embodiments and accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0044] As the requirements for battery energy density or fast charging increase, in order to match large-capacity battery cells, multi-layer tabs are required. When the multi-layer tabs and adapters are laser welded, because there are multiple tabs, the outer tabs need to be bent, so the transmission path becomes longer, resulting in a larger width of the uncoated area of the active material layer on the current collector. In addition, in order to increase the energy density, the current collector will become thinner and thinner, and ultra-thin current collectors are prone to wrinkling. To this end, by providing a reinforcement layer in the uncoated area of the active material layer on the current collector, the wrinkling of the current collector can be reduced, thereby improving the safety performance of the battery while ensuring that the battery meets the requirements of energy density and fast charging.

[0045] The present application provides an electronic device, which includes at least one battery, and the battery is used to provide electrical energy. The electronic device may be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, and an electric tool, etc. In one embodiment of the present invention, the vehicle is, for example, a new energy vehicle, which may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.

[0046] This application also provides a battery capable of being used in the aforementioned electronic device, comprising a pole piece. In one embodiment, the pole piece includes a current collector, and at least one side of the current collector includes an active material layer-coated region and an active material layer-uncoated region adjacent to each other along a first direction, wherein the active material layer-coated region is coated with an active material layer. A reinforcing layer is coated on at least a portion of the active material layer-uncoated region. The pole piece is, for example, a negative electrode pole piece.

[0047] See also Figure 1As shown, in one embodiment of the present invention, a pole piece 100 includes a current collector 110, and at least one side of the current collector 110 includes an active material layer-coated area 101 and an active material layer-uncoated area 102 adjacently arranged along a first direction Y. An active material layer 120 is coated on the active material layer-coated area 101. A reinforcing layer 130 is coated on at least a portion of the active material layer-uncoated area 102 along a second direction X, and the second direction X is perpendicular to the first direction Y. Along the first direction Y, the width of the active material layer-uncoated area 102 is W1 mm, and the width of the reinforcing layer 130 is W2 mm, satisfying 2.5 ≤ W1 / W2 ≤ 7.5. In a specific embodiment of the present invention, the width W2 of the reinforcing layer 130 is, for example, 3 mm to 12 mm. When the width of the uncoated area 102 of the active material layer is large, there is a high risk that the uncoated area 102 of the active material layer will be folded or wrinkled during die-cutting and winding. By controlling the ratio of the width of the uncoated area 102 of the active material layer to the width of the reinforcing layer 130, when the width of the uncoated area 102 of the active material layer is large, the reinforcing layer 130 can play a supporting role to avoid folding and wrinkling. When the width of the uncoated area 102 of the active material layer is small, it can also avoid the width of the reinforcing layer 130 occupying the welding area of the uncoated area 102 of the active material layer for connection with the external pole, thereby affecting the welding of the uncoated area 102 of the active material layer.

[0048] See also Figure 1 As shown, in one embodiment of the present invention, along the first direction Y, there is a preset spacing between the active material layer 120 and the reinforcement layer 130, denoted as G mm, satisfying 22≤W1 / G≤400. In a specific embodiment of the present invention, the preset spacing G is, for example, 0.1 mm to 1.1 mm. By controlling the ratio W1 / G, within a suitable range of the width of the uncoated area 102 of the active material layer and the preset spacing, the preset spacing is prevented from being too large, which would weaken the reinforcement layer and potentially result in insufficient welding area for connection to the external terminal in the uncoated area 102 of the active material layer. By taking into account the width of the uncoated area 102 of the active material layer and the preset spacing, the preset spacing is prevented from being too small, which would cause the reinforcement layer 130 and the active material layer 120 to blend with each other, resulting in bulging edges, etc., thereby making the boundary between the reinforcement layer 130 and the active material layer 120 clear, thereby improving battery performance and reducing safety hazards.

[0049] See also Figure 1As shown, in one embodiment of the present invention, along the first direction Y, the width of the active material layer 120 is W3mm, satisfying 3≤W3 / W1≤11. In a specific embodiment of the present invention, the width W1 of the uncoated area 102 of the active material layer is, for example, 30mm-40mm. By controlling the ratio of the width of the active material layer 120 to the width of the uncoated area 102 of the active material layer, on the basis of providing a reinforcement layer, the widths of the active material layer 120 and the uncoated area 102 of the active material layer can be taken into account, thereby facilitating the bending of the uncoated area to electrically connect with the pole, and avoiding folding and wrinkling, while taking into account the balance of the mass energy density of the battery.

[0050] See also Figure 1 and Figure 2 As shown, in one embodiment of the present invention, the current collector 110 is, for example, a negative electrode current collector, and the current collector 110 is, for example, copper foil. At least one side of the current collector 110 includes an active material layer-coated area 101 and an active material layer-uncoated area 102 adjacent to each other along a first direction Y. An active material layer 120 is coated on the active material layer-coated area 101, and a reinforcement layer 130 is provided on a portion of the active material layer-uncoated area 102. In another embodiment of the present invention, the active material layer 120 is provided on both sides of the current collector 110, and a reinforcement layer 130 is provided on both sides of the current collector 110 along the first direction Y, spaced apart from the active material layer 120. That is, the current collector 110 has two surfaces that face each other in its thickness direction, and the active material layer 120 and the reinforcement layer 130 are disposed simultaneously and spaced apart on one surface of the current collector 110; or the active material layer 120 is disposed simultaneously on both surfaces of the current collector 110, and the reinforcement layer 130 is disposed on one surface of the current collector 110; or the active material layer 120 and the reinforcement layer 130 are disposed simultaneously and spaced apart on both surfaces of the current collector 110. The thickness of the reinforcement layer 130 on one side of the current collector is H μm, and the thickness of the current collector 110 is h μm, satisfying 1 ≤ H / h ≤ 6. The ratio of the thickness of the active material layer 120 on one side of the current collector to the thickness of the current collector 110 is, for example, 5.5-34. In a specific embodiment of the present invention, the thickness h of the current collector 110 is, for example, 4 μm-5.5 μm, and the thickness of the active material layer 120 on one side is, for example, 30 μm-150 μm. The thinner the current collector, the more likely it is to wrinkle during die-cutting and winding. For thin materials ≤5.5μm, setting appropriate active material layer and current collector thicknesses and matching the reinforcement layer design can prevent current collector wrinkling and maintain the strength of the uncoated area of the active material layer, avoiding the problem of wavy edges caused by laser cutting at the junction of the active material layer and the uncoated area of the active material layer. At the same time, improving the bottom support of the uncoated area of the active material layer prevents the tabs from being inserted inward when bending.

[0051] See also Figure 1 and Figure 2As shown, in one embodiment of the present invention, the active material layer 120 is, for example, a negative electrode active material layer. The active material layer 120 includes, for example, a negative electrode active material, a negative electrode binder, a thickener, and a negative electrode conductive agent. The negative electrode active material is, for example, selected from any one or a combination of at least two of soft carbon, hard carbon, artificial graphite, silicon, silicon oxide, silicon carbon compound, or lithium titanate. The negative electrode binder is, for example, selected from any one or more of polypropylene, polyacrylic acid and its derivatives, or styrene-butadiene rubber. The negative electrode conductive agent is, for example, selected from any one or more of conductive carbon black (Super-P, SP), acetylene black, carbon nanotubes, and graphene. The thickener is, for example, selected from sodium carboxymethyl cellulose. The thickness of the active material layer 120 is consistent on the current collector 110, which can improve the charge and discharge consistency of the battery. This application does not limit the mass ratio of the negative electrode active material, negative electrode binder, thickener, and negative electrode conductive agent, and the selection is based on the preparation requirements.

[0052] See also Figure 1 and Figure 2As shown, in one embodiment of the present invention, the reinforcing layer 130 includes, for example, ceramic particles, an aqueous binder and a color developer, wherein the ceramic particles include, for example, at least one of boehmite, aluminum oxide, titanium dioxide, zirconium dioxide, zinc oxide, barium sulfate, boron nitride, aluminum nitride or magnesium nitride, and the aqueous binder includes, for example, at least one of polyacrylic acid (PAA), styrene butadiene rubber (SBR), polyvinyl alcohol (PVA), polyacrylamide (PAM), methyl cellulose and its salts, chitosan and its salts, alginic acid and its salts, and the color developer includes, for example, at least one of carbon black, chromium oxide green, cobalt green, cobalt blue, iron blue, cadmium red, carbon black or iron oxide red. By providing a color developer within the reinforcing layer 130, the grayscale value of the reinforcing layer 130 is, for example, 0-110, thereby increasing the color difference between the reinforcing layer 130 and the current collector 110, and the grayscale value of the reinforcing layer is smaller than the grayscale value of the current collector. During the die-cutting process of forming the tab, it is easier for the charge-coupled device detection (CCD) to identify the size and position of the reinforcing layer 130. The reinforcing layer 130 can absorb laser energy, reducing reflection and scattering of the laser, making the laser energy more concentrated, thereby reducing die-cutting power and energy consumption, and making the cut edge less prone to burrs, thereby reducing the problem of short circuits caused by burrs. By selecting a water-based binder, when preparing the reinforcing layer 130, the negative electrode production line can be made to not require organic gas recovery equipment. The ceramic particles can take into account the support of the reinforcement layer 130, thereby improving the design of the width of the uncoated area 102 of the active material layer, obtaining a larger width of the uncoated area 102 of the active material layer, and at the same time, improving the insulation of the reinforcement layer 130 to avoid leakage.

[0053] See also Figure 1 and Figure 2 As shown, in one embodiment of the present invention, the mass ratio of ceramic particles, aqueous binder, and color developer in the reinforcement layer 130 is, for example, 10-20:75-90:0.5-5. The high content of aqueous binder improves the adhesion between the reinforcement layer 130 and the current collector 110, preventing the reinforcement layer 130 from peeling off during the bending process of the subsequently formed tab. In one embodiment of the present invention, during the bending process of the tab, the peeling force between the reinforcement layer 130 and the current collector 110 is greater than 300 N / m.

[0054] See also Figure 2As shown, in one embodiment of the present invention, when forming the active material layer 120 and the reinforcement layer 130, the negative electrode active material, negative electrode binder, thickener, and negative electrode conductive agent are dispersed in water in a certain mass ratio to obtain a negative electrode slurry. Ceramic particles, an aqueous binder, and a color developer are dispersed in water in a certain mass ratio to obtain a reinforcement layer slurry. During the coating process, the negative electrode slurry and the reinforcement layer slurry are simultaneously coated on the current collector 110 and dried to obtain the active material layer 120 and the reinforcement layer 130.

[0055] See also Figure 3 and Figure 4 As shown, in one embodiment of the present invention, the electrode sheet 100 further includes a tab 140, wherein a portion of the active material layer 120 covers at least a portion of the surface of the tab 140 along the first direction Y. In this case, the height of the tab 140 includes the size of the active material layer that may extend to both the front and back sides of the tab 140.

[0056] See also Figure 5 and Figure 6 As shown, in another embodiment of the present invention, the electrode 100 further includes a tab 140, a transition region 160 is provided between the tab 140 and the active material layer coating region 101, and the reinforcement layer 130 is located on a portion of the transition region 160 and a portion of the surface of the tab 140. In this case, the height of the tab includes the size of the reinforcement layer located on the portion of the tab 140.

[0057] See also Figure 3 and Figure 5 As shown, in one embodiment of the present invention, after forming the active material layer 120 and the reinforcement layer 130, the tab 140 is obtained by die-cutting a portion of the active material layer uncoated area 102 or die-cutting the active material layer uncoated area 102 and a portion of the active material layer coated area 101. The die-cutting stop position is recorded as the shoulder B of the tab 140, and the tab 140 extends from the shoulder B to the side of the active material layer uncoated area 102 away from the active material layer 120. By providing the transition zone 160, the laser energy of the die-cutting can be reduced, and the energy consumption can be reduced. That is, compared with die-cutting to a portion of the area provided with the active material layer, the laser energy is lower, the laser power is reduced, the foil leakage phenomenon is reduced, the energy density and cycle performance of the battery are improved, and the safety performance is improved.

[0058] See also Figures 3 to 6As shown, in one embodiment of the present invention, the tab 140 further includes a plurality of reinforcing ribs 150, and the reinforcing ribs 150 are stamped from the tab 140. The reinforcing ribs 150 are arranged on the tab 140 in at least one shape, such as a dot shape, a strip shape, a wave shape, or a broken line shape. In addition, along the first direction and / or the second direction, each two adjacent reinforcing ribs 150 are spaced apart from each other. When the reinforcing ribs 150 are distributed in a strip shape, the reinforcing ribs 150 are similar to a plurality of parallel long strips. The ratio of the width of the maximum overlapping position of the reinforcing ribs 150 and the reinforcing layer 130 (W4 mm) to the width of the reinforcing layer 130 (W2 mm) is 0.1-1, wherein the maximum distance from the reinforcing ribs 150 located on the reinforcing layer 130 away from the first direction to the side of the reinforcing layer 130 away from the active material layer 120 is defined as W4. When W4 / W2 is 1, it means that the reinforcing rib 150 at least overlaps with the side of the reinforcing layer 130 close to the active material layer 120, or part of the reinforcing rib 150 is located within a preset distance between the reinforcing layer 130 and the active material layer 120. In a specific embodiment of the present invention, after the tab 140 is formed, the reinforcing rib 150 is obtained, for example, by stamping the current collector 110 in the area of the tab 140. In other embodiments, the reinforcing rib 150 can also be made in other ways, for example, the reinforcing rib 150 is formed separately and then fixed on the current collector 110. By controlling the ratio of W4 / W2 within a suitable range, the strength of the reinforcing layer can be improved, the tab wrinkles can be reduced, and the width of the uncoated area 102 of the active material layer can be further increased, so as to adapt to more layers of tabs and reduce the direct current resistance (DCR) of the battery.

[0059] See also Figure 7 As shown, in one embodiment of the present invention, the battery further includes a housing 10 having an upper opening, an electrode assembly disposed within the housing 10, and a cover assembly 11 that closes the upper opening. The present invention does not limit the type and shape of the battery. The battery may be, for example, a primary battery or a secondary battery. The secondary battery may be, for example, a pouch cell, a cylindrical cell, or a prismatic cell, or a sodium ion secondary battery or a lithium ion secondary battery. In this embodiment, a lithium ion secondary battery is used as an example for illustration.

[0060] See also Figures 7 to 9As shown, in one embodiment of the present invention, when the secondary battery is, for example, a square shell battery, the square shell battery includes, for example, a shell 10, a cover plate assembly 11, and an electrode assembly 20 disposed in the shell 10, and the tabs of the electrode assembly 20 are electrically connected to the poles on the shell 10. The shape of the shell 10 matches the shape of the electrode assembly 20, and the material of the shell 10 is, for example, an aluminum shell, a steel shell, or a flexible shell, and the shell 10 is a receiving cavity with an upper end opening for accommodating the electrode assembly 20. Specifically, after the electrode assembly 20 is placed in the shell 10 through the upper end opening, the shell 10 is sealed with the cover plate assembly 11. The first pole 12, the second pole 13, the explosion-proof valve 14, and the injection hole 15 are provided on the cover plate assembly 11. The electrolyte is injected through the injection hole 15, and the injection hole 15 is then sealed. The first electrode 12 and the second electrode 13 have opposite polarities, and are respectively positive or negative. The present invention does not limit the specific polarity categories of the first electrode 12 and the second electrode 13. The first electrode 12 is electrically connected to the tab of the same polarity on the electrode assembly 20, and the second electrode 13 is electrically connected to the tab of the same polarity on the electrode assembly 20. In this embodiment, the positions of the first electrode 12 and the second electrode 13 are not limited and can be located at the same end of the housing or at both ends of the housing, depending on the position of the tabs on the electrode assembly 20 or design requirements.

[0061] See also Figure 7 As shown, in one embodiment of the present invention, when the first and second poles 12 and 13 are disposed at one end of the housing, the explosion-proof valve 14 and the injection hole 15 are disposed between the first and second poles 12 and 13. For example, the explosion-proof valve 14 is disposed midway between the first and second poles 12 and 13, with a predetermined distance therebetween. The injection hole 15 is disposed between the explosion-proof valve 14 and the first pole 12, or between the explosion-proof valve 14 and the second pole 13. That is, the explosion-proof valve 14, the injection hole 15, the first and second poles 12 and 13 are spaced apart from each other. The explosion-proof valve 14 can activate its ventilation function when the battery cell is operating normally, allowing air to flow inside and outside the battery cell while preventing particulate matter from flowing. In the event of thermal runaway of the battery cell, when the pressure difference between the inside and outside of the battery cell reaches a predetermined explosion-proof value, the explosion-proof valve opens, allowing both gas and solids to be discharged from the inside of the battery cell to the outside of the battery cell through the explosion-proof valve, thereby improving the safety performance of the battery cell.

[0062] See also Figures 8 and 9As shown, in one embodiment of the present invention, the electrode assembly 20 includes a negative electrode sheet, a positive electrode sheet 200 and a separator 300. The negative electrode sheet is selected from the above-mentioned electrode sheet 100. The separator 300 is arranged between the positive electrode sheet 200 and the negative electrode sheet to prevent the positive electrode sheet 200 and the negative electrode sheet from contacting each other and causing safety problems. An electrolyte (not shown in the figure) is filled between the negative electrode sheet, the positive electrode sheet 200 and the separator 300, and between the electrode assembly 20 and the shell to conduct ions between the positive and negative electrode sheets. The electrolyte is any applicable lithium-ion battery electrolyte. The stacking method of the positive and negative electrode sheets is not specifically limited in this application, and is selected according to the specific manufacturing requirements.

[0063] In one embodiment of the present invention, the electrolyte includes, for example, an organic solvent and a lithium salt. The organic solvent is selected from any one or more of ethylene carbonate (EC), propylene carbonate (PC), ethyl acetate (EA), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), or diethyl carbonate (DEC). The lithium salt is selected from any one or more of lithium bis(fluorosulfonyl)imide (LiFSi), lithium difluorophosphate (LiPO2F2), lithium hexafluorophosphate (LiPF6), or lithium tetrafluoroborate (LiBF4). In one embodiment of the present invention, the lithium salt is selected from lithium hexafluorophosphate, for example, and the organic solvent is selected from a mixture of ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, and propylene carbonate. Ethylene carbonate, ethyl methyl carbonate, diethyl carbonate and propylene carbonate are mixed, for example, in a volume ratio of 1:1:1:1, and fully dried LiPF6 is dissolved in a mixed organic solvent in an argon atmosphere glove box with a water content of less than 10 ppm. After mixing evenly, an electrolyte is obtained, wherein the concentration of LiPF6 is, for example, 1 mol / L.

[0064] See also Figures 8 and 9As shown, in one embodiment of the present invention, the electrode sheet 100 and the positive electrode sheet 200 are formed into the electrode assembly 20 by, for example, winding or laminating. The lamination can be, for example, a stacked laminate or a Z-shaped laminate, and this application does not impose any specific restrictions. The separator 300 can be, for example, a polyethylene film (PE), a polypropylene film (PP), a glass fiber film, a polyethylene film, or a composite film. In this application, the thickness of the separator 300 is not limited, and can be any thickness that meets the requirements of use.

[0065] See also Figure 10 As shown, in one embodiment of the present invention, the positive electrode plate 200 includes a positive electrode current collector 210 and a positive electrode active material layer 220 coated on at least one surface of the positive electrode current collector 210. That is, the positive electrode current collector 210 has two surfaces opposite to each other in its own thickness direction, and the positive electrode active material layer 220 can be provided on any one or both of the two surfaces of the positive electrode current collector 210. The positive electrode current collector 210 can be an aluminum foil current collector, and the thickness of the aluminum foil current collector is, for example, 5μm-20μm. Further, the thickness of the aluminum foil current collector is, for example, 10μm-15μm. The positive electrode current collector 210 can also be a composite current collector, which includes a polymer matrix and aluminum layers located on the upper and lower surfaces of the polymer matrix. The polymer matrix can be polyethylene terephthalate, polypropylene, polyimide, polystyrene or polyamide, etc.

[0066] See also Figure 10 As shown, in one embodiment of the present invention, on the positive electrode current collector 210, the area coated with the positive electrode active material layer 220 is defined as the electrode sheet area, and the area of the positive electrode current collector 210 not coated with the positive electrode active material layer 220 is defined as the positive electrode tab area 230, which is used to form the positive electrode tab. The electrode sheet area and the positive electrode tab area 230 are arranged adjacent to each other. The positive electrode active material layer 220 includes a positive electrode active material, a positive electrode conductive agent, and a positive electrode binder. The positive electrode active material can be selected from one or more combinations of lithium nickel cobalt manganese oxide, lithium nickel manganese oxide, lithium titanate, lithium nickel cobalt manganese aluminum oxide, lithium iron phosphate, and lithium manganese iron phosphate. The positive electrode conductive agent can be selected from one or more of conductive carbon black, acetylene black, nanometal powder, graphene, carbon nanotubes, or carbon nanofibers, or a combination of two or more of these in any proportion. The positive electrode binder can be selected from one or more mixtures of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene, or polytetrafluoroethylene. The present invention does not limit the thickness of the positive electrode active material layer 220 , and the thickness is selected based on the battery design requirements.

[0067] See also Figure 11 and Figure 12As shown, in one embodiment of the present invention, the positive electrode plate 200 includes a plurality of positive electrode tabs 240, and part of the positive electrode active material layer 220 covers at least part of the surface of the positive electrode tab 240; or a connection area 241 is set between the positive electrode tab 240 and the positive electrode active material layer 220, and the connection area 241 is located in the positive electrode tab area 230, that is, the positive electrode active material layer 220 is not set on the connection area 241, and the positive electrode active material layer 220 does not cover the positive electrode tab 240.

[0068] See also Figure 4 、 Figure 6 and Figure 13As shown, in one embodiment of the present invention, the electrode sheet 100, the positive electrode sheet 200 and the separator 300 are made into an electrode assembly 20, for example, by winding or laminating. The electrode assembly 20 includes a main body 1 and an active material layer uncoated area 102 and a positive electrode tab 240 located at one end of the main body 1. The active material layer uncoated area 102 is used to form the tab 140 to serve as the negative electrode tab. Among them, the main body 1 is a part formed by the shoulder B of the tab as a laminate. The two electrode assemblies 20 are arranged oppositely in the shell 10. Each group of electrode assemblies 20 is provided with an active material layer uncoated area 102 and a positive electrode tab 240 at one end facing the cover assembly 11. The active material layer uncoated area 102 and the positive electrode tab 240 can be connected to the cover assembly 11 through the corresponding adapter 1112. The positive electrode tabs 240 of the two electrode assemblies 20 are welded to each other, and the active material layer uncoated areas 102 of the two electrode assemblies 20 are welded to each other. The positive electrode tabs 240 and the active material layer uncoated areas 102 of the two electrode assemblies 20 are welded correspondingly and welded to the adapter sheet 1112. Then, the two sets of electrode assemblies 20 are bent relative to each other and then installed in the housing 10. The active material layer uncoated area 102 includes a connecting portion 111 and a bending portion 112. The connecting portion 111 is fixedly connected to the adapter sheet 1112. The bending portion 112 is connected between the main body 1 and the connecting portion 111. The reinforcing layer 130 covers at least a portion of the bending portion 112. The uncoated area 102 of the active material layer is covered with a first tape 30. The first tape 30 is located on the side of the uncoated area 102 facing away from the cover plate assembly 11 to protect the uncoated area 102 of the active material layer. The first tape 30 includes a first adhesive area 31, a second adhesive area 33, and a non-adhesive area 32 located between the first and second adhesive areas 31, 33. The first adhesive area 31 covers the main body 1, and the second adhesive area 33 covers the connection portion 111. In the thickness direction of the electrode assembly, the orthographic projection of the reinforcement layer 130 is completely located within the non-adhesive area 32, thereby preventing the reinforcement layer from falling off when the tab is static or when the tab is assembled. The positive electrode tab 240 is covered with a second tape 40. The second tape 40 is located on the side of the positive electrode tab 240 facing away from the cover plate assembly 11 to protect the positive electrode tab 240. The tape improves the safety of the leaking foil, and the non-sticky area covers the reinforcement layer to prevent the reinforcement layer from falling off. The tape provides support to prevent the negative electrode tab from being inserted and torn.

[0069] Hereinafter, the present invention will be explained in more detail by citing examples, which should not be construed as limiting. Appropriate modifications may be made within the scope consistent with the gist of the present invention, all of which fall within the technical scope of the present invention.

[0070] Example 1

[0071] Preparation of the negative electrode sheet: Boehmite, polyacrylic acid, and carbon black are mixed in a mass ratio of 20:75:5, deionized water is added, and the mixture is mixed evenly in a vacuum mixer to obtain a reinforcement layer slurry. Artificial graphite, conductive carbon black, sodium carboxymethyl cellulose, and styrene-butadiene rubber are mixed in a mass ratio of 96:1:1:2, deionized water is added, and the mixture is mixed evenly in a vacuum mixer to obtain a negative electrode slurry. The negative electrode slurry and reinforcement layer slurry are simultaneously coated on a 6μm thick copper foil, transferred to an oven for drying, and subjected to processes such as rolling, slitting, die-cutting, and cutting to obtain a negative electrode sheet. When forming the tab, the shoulder of the tab is located within the reinforcement layer, i.e., a transition zone is provided. The width of the active material layer coating area is 210 mm, the width of the uncoated area of the active material layer is 30 mm, the width of the reinforcing layer is 12 mm, the thickness of the reinforcing layer is 18 μm, and the preset spacing between the reinforcing layer and the active material layer is 0.6 mm, that is, the ratio of the width of the uncoated area of the active material layer to the width of the reinforcing layer is 2.5, the ratio of the width of the uncoated area of the active material layer to the preset spacing is 50, the ratio of the thickness of the reinforcing layer to the thickness of the current collector is 3, the ratio of the width of the active material layer to the uncoated area of the active material layer is 7, and the ratio of the width of the maximum overlapping position of the reinforcing rib and the reinforcing layer to the width of the reinforcing layer is 0.5.

[0072] Preparation of positive electrode: LiNi 08 Co 0.1 Mn 0.1 After mixing O2, acetylene black, and polyvinylidene fluoride in a mass ratio of 97:1:2, N-methylpyrrolidone was added and stirred in a vacuum mixer until the system was uniform to obtain a positive electrode slurry. The positive electrode slurry was evenly coated on aluminum foil, then dried at room temperature and transferred to an oven for drying. After cold pressing, trimming, cutting, and slitting, the positive electrode sheet was obtained.

[0073] Preparation of electrolyte: Ethylene carbonate, ethyl methyl carbonate, diethyl carbonate and propylene carbonate are mixed in a volume ratio of 1:1:1:1. In an argon atmosphere glove box with a water content of less than 10 ppm, fully dried LiPF6 is dissolved in a mixed organic solvent, and the mixture is mixed evenly to obtain an electrolyte, wherein the concentration of LiPF6 is, for example, 1 mol / L.

[0074] Selection of diaphragm: Polyethylene with a thickness of 9 μm is used as the diaphragm.

[0075] Battery Preparation: The positive electrode sheet, separator, and negative electrode sheet are stacked in sequence and wound, with the separator positioned between the positive and negative electrodes to provide isolation. Except for the innermost and outermost circles, each circle of the negative electrode sheet has a tab, resulting in a wound bare cell. The bare cell is then placed in an aluminum casing, fitted with a top cover assembly, and then electrolyte is injected and sealed to create a lithium-ion battery.

[0076] Example 2

[0077] The width of the reinforcement layer is 6 mm, that is, the ratio of the width of the uncoated area of the active material layer to the width of the reinforcement layer is 5. The remaining operations are the same as those in Example 1.

[0078] Example 3

[0079] The width of the reinforcement layer is 4 mm, that is, the ratio of the width of the uncoated area of the active material layer to the width of the reinforcement layer is 7.5. The remaining operations are the same as those in Example 1.

[0080] Example 4

[0081] The width of the uncoated area of the active material layer is 40 mm, and the width of the reinforcing layer is 8 mm, that is, the ratio of the width of the uncoated area of the active material layer to the width of the reinforcing layer is 5. The remaining operations are the same as in Example 1.

[0082] Example 5

[0083] The width of the uncoated area of the active material layer is 40 mm, the preset spacing between the reinforcing layer and the active material layer is 0.1 mm, the ratio of the width of the uncoated area of the active material layer to the preset spacing is 400, and the remaining operations are the same as in Example 2.

[0084] Example 6

[0085] The preset distance between the reinforcing layer and the active material layer is 1.1 mm, the ratio of the width of the uncoated area of the active material layer to the preset distance is 27.3, and the remaining operations are the same as those in Example 2.

[0086] Example 7

[0087] The thickness of the reinforcement layer is 6 μm, the ratio of the thickness of the reinforcement layer to the thickness of the current collector is 1, and the remaining operations are consistent with those in Example 2.

[0088] Example 8

[0089] The thickness of the reinforcement layer is 36 μm, the ratio of the thickness of the reinforcement layer to the thickness of the current collector is 6, and the remaining operations are consistent with those in Example 2.

[0090] Example 9

[0091] The thickness of the current collector is 5.5 μm, the thickness of the reinforcement layer is 16.5 μm, the ratio of the thickness of the reinforcement layer to the thickness of the current collector is 3, and the remaining operations are consistent with Example 2.

[0092] Example 10

[0093] The thickness of the current collector is 4.5 μm, the thickness of the reinforcement layer is 13.5 μm, the ratio of the thickness of the reinforcement layer to the thickness of the current collector is 3, and the remaining operations are consistent with Example 2.

[0094] Example 11

[0095] The thickness of the current collector is 4 μm, the thickness of the reinforcement layer is 12 μm, the ratio of the thickness of the reinforcement layer to the thickness of the current collector is 3, and the remaining operations are consistent with Example 2.

[0096] Comparative Example 1

[0097] The width of the reinforcement layer is 15 mm, that is, the ratio of the width of the uncoated area of the active material layer to the width of the reinforcement layer is 2. The remaining operations are the same as those in Example 1.

[0098] Comparative Example 2

[0099] The width of the reinforcement layer is 3.5 mm, that is, the ratio of the width of the uncoated area of the active material layer to the width of the reinforcement layer is 8.6. The remaining operations are the same as those in Example 1.

[0100] Comparative Example 3

[0101] The preset distance between the reinforcing layer and the active material layer is 1.4 mm, the ratio of the width of the uncoated area of the active material layer to the preset distance is 21.4, and the remaining operations are the same as those in Example 2.

[0102] Comparative Example 4

[0103] The preset distance between the reinforcing layer and the active material layer is 0.05 mm, the ratio of the width of the uncoated area of the active material layer to the preset distance is 600, and the remaining operations are the same as those in Example 2.

[0104] In one embodiment of the present invention, in order to obtain the tab wrinkle performance, after obtaining the bare battery cell, the distance from the side of each tab away from the active material layer to the active material layer is tested by a camera, and the difference from the design value of the width of the uncoated area of the active material layer is calculated (if it is the design value after the battery is disassembled, for tabs of equal height, the maximum value of the uncoated area width is taken), and the average value of the difference is obtained, and the average value is defined as the tab deviation value (if the deviation value of the uncoated area of the active material layer is obtained, the distance from the side of the uncoated area of each active material layer away from the active material layer to the active material layer is obtained by a camera). The tab deviation value is used to characterize the tab wrinkle performance. The smaller the tab deviation value, the less wrinkles the tab has.

[0105] In one embodiment of the present invention, in order to obtain the folding condition of the tab, after obtaining the bare battery cell, the orthographic projection area of each tab on the plane where the current collector is located is obtained by a CCD camera, which is recorded as S1, and the orthographic projection area of each tab on the plane where the current collector is located after being flattened is recorded as S2 (if the folding condition of the uncoated area of the active material layer is obtained, the orthographic projection area of the uncoated area of each layer of the active material layer on the plane where the current collector is located, and the orthographic projection area of the uncoated area of each layer of the active material layer on the plane where the current collector is located after being flattened) is obtained by a CCD camera, and the calculation error = (S2-S1) / S2×100%, and the tab with an error greater than 5% is defined as a tab with folding, and the ratio of the number of tab layers with folding to the total number of tab layers is calculated.

[0106] In one embodiment of the present invention, after obtaining the negative electrode sheet, it is observed whether the reinforcing layer and the negative electrode active material layer are fused. The fused state is that the material of the active material layer is fused in the reinforcing layer area, and the unfused appearance state is that the reinforcing layer and the active material layer are completely separated, and the corresponding spacing is relatively uniform.

[0107] In one embodiment of the present invention, after disassembling the battery cells of Examples 1-11 and Comparative Examples 1-4, the actual number of tab welding layers is observed, and the ratio of the actual number of tab welding layers to the designed number of tabs is calculated (if the number of welding layers in the uncoated area of the active material layer is obtained, the actual number of welding layers and the designed number of layers in the uncoated area of the active material layer are obtained).

[0108] Table 1. Some characteristics and properties of the negative electrode sheets in Examples 1-4 and Comparative Examples 1-2

[0109]

[0110] As shown in Table 1, a comparison of Examples 1-4 and Comparative Examples 1-2 shows that when the width of the reinforcement layer is small, that is, when W1 / W2 is large, the deviation value of the uncoated area of the active material layer is large, and the proportion of folds in the uncoated area of the active material layer is large, indicating that the uncoated area of the active material layer has more wrinkles and folds. As the width of the reinforcement layer gradually increases, the deviation value of the uncoated area of the active material layer gradually decreases, and the proportion of folds in the uncoated area of the active material layer is less than 0.5%, indicating that increasing the width of the reinforcement layer can reduce wrinkles and folds in the uncoated area of the active material layer. When the width of the reinforcement layer is too large, that is, when W1 / W2 is less than 2.5, the area used for welding in the uncoated area of the active material layer and the adapter will cause a cavity explosion when welding. As a result, the number of welding layers in the actual uncoated area of the active material layer is different from the number of layers designed for the uncoated area of the active material layer, which may increase the interface contact resistance and reduce the bonding strength between the uncoated area of the active material layer and the electrode. This may further cause the uncoated area of the active material layer to fall off or become a poor connection, or a significant local temperature rise in the battery, which may trigger a thermal runaway chain reaction. Therefore, controlling W1 / W2 within the range of 2.5-7.5 can improve the safety performance of the battery while reducing wrinkles and folds in the uncoated area of the active material layer.

[0111] Table 2. Some characteristics and properties of the negative electrode sheets in Examples 2, 5-6 and Comparative Examples 3-4

[0112]

[0113] Please refer to Table 2. It can be seen from Comparative Examples 2, 5-6 and Comparative Examples 3-4 that when the ratio of the width of the uncoated area of the active material layer to the preset spacing between the reinforcing layer and the active material layer is greater than 400, that is, when the preset spacing is small, the reinforcing layer and the negative electrode active material layer fuse, which may lead to problems such as abnormal interface contact and stress concentration, and also cause a decrease in the utilization rate of the active material. As the preset spacing increases, that is, the W1 / G ratio decreases, the fusion of the reinforcing layer and the negative electrode active material layer can be avoided, and as the W1 / G ratio decreases, the ear deviation value is relatively stable, but when the W1 / G ratio is less than 22, the ear deviation value is large. This is because the spacing between the reinforcing layer and the active material layer is too large, and the role of the reinforcing layer cannot be played, resulting in an increase in wrinkles. Therefore, controlling the W1 / G ratio reduces the mutual dissolution and reduces the wrinkles and folding of the ear, thereby improving the safety performance of the battery.

[0114] Table 3. Some characteristics and performance of the negative electrode sheets in Examples 2, 7-11

[0115]

[0116] As shown in Table 3, a comparison of Examples 2, 7, and 8 shows that when the current collector thickness is consistent, as the ratio of the reinforcement layer thickness to the current collector thickness increases, the tab deviation value and the percentage of tab folding decrease. This indicates that increasing the thickness of the reinforcement layer can reduce tab wrinkling and folding. As the ratio increases, the tab deviation value and the percentage of tab folding tend to stabilize. To control costs, the ratio of the reinforcement layer thickness to the current collector thickness is controlled between 1 and 6. A comparison of Examples 2, 9, and 11 shows that when the ratio of the reinforcement layer thickness to the current collector thickness is consistent, as the current collector thickness decreases, the tab deviation value and the percentage of tab folding increase, but overall remain within a small range. This indicates that as the current collector thickness decreases, the number of tab wrinkles and folds increases. The provision of a reinforcement layer can improve the wrinkling and folding of the tab. Therefore, as the current collector thickness decreases, the ratio of the reinforcement layer thickness to the current collector thickness can be increased to improve the wrinkling and folding of the tab.

[0117] In summary, the pole piece provided by the present invention and the battery and electronic device including the same, by providing a reinforcing layer, can make the reinforcing layer play a better supporting effect when the width of the uncoated area of the active material layer is large, avoiding the occurrence of wrinkles, folds and tab insertion in the uncoated area of the active material layer, and can also avoid the reinforcing layer from being too wide and occupying the area used for welding in the uncoated area of the active material layer, and can ensure the size of the welding area of the uncoated area of the active material layer, thereby improving the safety performance of the battery. By controlling the preset spacing, it is possible to avoid situations such as bulging caused by the mutual blending of the reinforcing layer and the active material layer, while ensuring the tab welding area, and reducing the wrinkles and folds of the tab, thereby improving battery performance and reducing safety hazards. It can be applied to thinner current collectors, and can reduce the wrinkling of the current collector in the case of thinner current collectors or multi-layer tabs. By controlling the composition of the reinforcing layer, the negative electrode production line can eliminate the need for organic gas recovery equipment, simplifying the preparation process. By controlling the grayscale value of the reinforcing layer, the reflection of the laser can be reduced during laser cutting. For the same cut thickness, the laser power can be lower, which can reduce the laser energy for die cutting, reduce energy consumption, reduce foil leakage, improve the energy density and cycle performance of the battery, and improve the adhesion between the reinforcing layer and the current collector, reducing the peeling of the reinforcing layer. By providing reinforcing ribs, the strength of the reinforcing layer can be increased, the wrinkles of the tabs can be reduced, and the width of the uncoated area of the active material layer can be further increased, thereby accommodating more layers of tabs and reducing the DC impedance of the battery.

[0118] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the inventive concept, such as the technical solutions formed by the mutual replacement of the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this application.

[0119] Except for the technical features described in the specification, the remaining technical features are known technologies to those skilled in the art. In order to highlight the innovative features of the present invention, the remaining technical features will not be described here in detail.

Claims

1. A pole piece, characterized in that: including a current collector, an active material layer and a reinforcement layer; At least one side of the current collector includes an active material layer coating area and an active material layer uncoated area adjacent to each other along a first direction; The active material layer is coated on the active material layer coating area; the reinforcing layer is coated on at least part of the active material layer uncoated area; along the first direction, the width of the active material layer uncoated area is W1 mm, and the width of the reinforcing layer is W2 mm, satisfying 2.5≤W1 / W2≤7.

5.

2. The pole piece according to claim 1, characterized in that: Along the first direction, there is a preset distance G mm between the active material layer and the reinforcement layer, which satisfies 22≤W1 / G≤400.

3. The pole piece according to claim 2, characterized in that: The preset spacing is 0.1 mm-1.1 mm.

4. The pole piece according to claim 1, characterized in that: Along the first direction, the width of the active material layer is W3 mm, satisfying 3≤W3 / W1≤11.

5. The pole piece according to claim 1, characterized in that: The ratio of the thickness of the reinforcement layer on one side to the thickness of the current collector is 1-6; or, The thickness of the current collector is 4 μm-5.5 μm.

6. The pole piece according to claim 1, characterized in that: The grayscale value of the enhancement layer is 0-110.

7. The pole piece according to claim 1, characterized in that: The electrode piece also includes a pole ear, and part of the active material layer covers at least part of the surface of the pole ear along the first direction; or, a transition zone is set between the pole ear and the active material layer coating area, and the reinforcement layer is located in part of the transition zone and part of the pole ear surface.

8. The pole piece according to claim 7, characterized in that: The tab also includes a plurality of reinforcing ribs, and the reinforcing ribs are stamped by the tab. The reinforcing ribs are arranged in at least one of a point shape, a strip shape, a wave shape or a broken line shape. The ratio of the width of the maximum overlapping position of the reinforcing rib and the reinforcing layer to the width of the reinforcing layer is 0.1-1.

9. The pole piece according to claim 1, characterized in that: The active material layer is arranged on both sides of the current collector, and the electrode is a negative electrode.

10. A battery, characterized in that: include: A shell having an upper opening; an electrode assembly, placed into the housing through the upper opening; as well as a cover plate assembly, closing the upper end opening; In which, the electrode assembly is formed by stacking a positive electrode sheet, a separator and a negative electrode sheet and then winding or laminating them, and the negative electrode sheet adopts the electrode sheet described in any one of claims 1 to 9; along the first direction, the electrode assembly includes a main body and an uncoated area of the active material layer, and the uncoated area of the active material layer includes a bending portion and a connecting portion, the connecting portion is fixedly connected to the cover plate assembly, and the bending portion is connected between the main body and the connecting portion; the reinforcement layer covers at least a partial area of the bending portion.

11. The battery according to claim 10, characterized in that The electrode assembly is covered with a first tape, which is arranged on the side of the active material layer uncoated area facing away from the cover assembly. The first tape includes a first adhesive area, a second adhesive area, and a non-adhesive area between the first adhesive area and the second adhesive area. The first adhesive area covers the main body, and the second adhesive area covers the connecting part. In the thickness direction of the electrode assembly, the orthographic projection of the reinforcement layer is completely located within the non-adhesive area.

12. An electronic device, characterized in that: A battery comprising the battery according to any one of claims 10 to 11.

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