Negative plate, battery and electric equipment

Abstract

The utility model discloses a negative plate, a battery and electric equipment, the negative plate comprises a negative current collector, a first blocking structure and a negative active material layer, and the negative current collector comprises a first edge; the first barrier structure is laminated on the negative electrode current collector; the negative electrode active material layer comprises a first area and a second area which are sequentially arranged in the first direction, the first area is closer to the first edge than the second area, the first edge extends in the second direction, and the second direction intersects with the first direction; at least part of the first region is stacked on the first blocking structure, the second region is stacked on the negative electrode current collector, and the first blocking structure is suitable for enabling the lithium ion intercalation and deintercalation capability of the first region to be reduced compared with the lithium ion intercalation and deintercalation capability of the second region. According to the negative electrode plate, the first barrier structure can reduce the transmission rate of lithium ions, so that the conductivity and the lithium ion de-intercalation capacity of the first region can be reduced compared with those of the second region, and the edge lithium precipitation effect generated by lithium ion migration and cyclic accumulation is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a negative electrode sheet, a battery and an electrical equipment. Background Art

[0002] In recent years, lithium-ion batteries have been widely used due to their advantages of high energy density, high working voltage, long service life and low self-discharge.

[0003] In the edge area of the electrode sheet of a lithium-ion battery, lithium precipitation will occur after multiple fast charge cycles due to poor charge and discharge capacity, and the accumulated precipitated lithium will cause the separator to be punctured, bringing serious safety hazards to the lithium-ion battery. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a negative electrode sheet, a battery and an electrical equipment to solve the problem that lithium is easily precipitated at the edge of the negative electrode sheet.

[0005] To achieve the purpose of the utility model, the following technical solutions are provided:

[0006] In a first aspect, the utility model provides a negative electrode sheet, which includes a negative electrode current collector, a first blocking structure and a negative electrode active material layer. The negative electrode current collector includes a first edge; the first blocking structure is laminated on the negative electrode current collector; the negative electrode active material layer includes a first region and a second region arranged in sequence in a first direction, and the first region is closer to the first edge than the second region. The first edge extends in a second direction, and the second direction intersects with the first direction; at least part of the first region is laminated on the first blocking structure, the second region is laminated on the negative electrode current collector, and the first blocking structure is adapted to reduce the ability of the first region to deintercalate lithium ions compared with the ability of the second region to deintercalate lithium ions.

[0007] In an embodiment, the thickness of the first blocking structure is a first thickness D, satisfying: 0.3μm ≤ D ≤ 6μm.

[0008] In an embodiment, the first blocking structure is hydrated alumina and / or an alumina member.

[0009] In an embodiment, the surface of the first region facing away from the first blocking structure is flush with the surface of the second region facing away from the negative electrode current collector.

[0010] In an embodiment, the first region includes a second edge and a third edge opposite to each other in the first direction. The second edge is close to the first edge, and the third edge is connected to the second region. In the first direction, the first blocking structure is located between the first edge and the third edge.

[0011] In one embodiment, the first blocking structure includes a first side and a second side that are opposite to each other in the first direction. The first side is closer to the first edge than the second side. In the first direction, the distance from the first side to the first edge is A1, satisfying: 0 mm ≤ A1 ≤ 2 mm.

[0012] In one embodiment, the first blocking structure includes a first side and a second side that are opposite to each other in the first direction. The first side is closer to the first edge than the second side. The distance from the first side to the second side is B1, satisfying: 1 mm ≤ B1 ≤ 10 mm.

[0013] In one embodiment, the negative electrode sheet further includes a second blocking structure, the second blocking structure is stacked on the negative electrode current collector, the negative electrode active material layer further includes a third region, the third region is located on a side of the second region facing away from the first region in the first direction, and the third region is stacked on the second blocking structure. The second blocking structure is adapted to reduce the ability of the third region to intercalate and deintercalate lithium ions compared to the ability of the second region to intercalate and deintercalate lithium ions.

[0014] In one embodiment, the negative electrode current collector further includes a fourth edge opposite to the first edge in the first direction. The third region includes a fifth edge and a sixth edge that are opposite to each other in the first direction. The fifth edge is close to the fourth edge, and the sixth edge is connected to the second region. In the first direction, the second blocking structure is located between the fourth edge and the sixth edge.

[0015] In one embodiment, the negative electrode sheet further includes a third blocking structure, the third blocking structure is stacked on the negative electrode current collector, the negative electrode current collector further includes a seventh edge adjacent to the first edge, the negative electrode active material layer further includes a fourth region, the fourth region and the second region are arranged in sequence in a second direction, and the fourth region is closer to the seventh edge than the second region. The second direction intersects with the first direction. The fourth region is stacked on the third blocking structure. The third blocking structure is adapted to reduce the ability of the fourth region to intercalate and deintercalate lithium ions compared to the ability of the second region to intercalate and deintercalate lithium ions.

[0016] In one embodiment, the negative electrode sheet includes an overlapping region and an overhang region. The overlapping region is adapted to overlap with the positive electrode active material layer of the positive electrode sheet, and the overhang region includes at least a part of the first region.

[0017] In one embodiment, the size of the overhang region in the first direction is a first size P, satisfying: 1 mm ≤ P ≤ 3 mm.

[0018] In a second aspect, the present utility model further provides a battery, including a positive electrode sheet and a negative electrode sheet as described in any one of the various embodiments of the first aspect. In the orthographic projection of the positive electrode sheet on the negative electrode sheet, the edge of the positive electrode active material layer of the positive electrode sheet falls within the first region.

[0019] In a third aspect, the present utility model further provides an electrical device, including an electrical device and the battery as described in the second aspect, and the battery supplies power to the electrical device.

[0020] By providing the first barrier structure stacked on the negative current collector, the first region of the negative electrode active material layer is closer to the first edge relative to the second region, and at least a part of the first region is stacked on the first barrier structure, and the second region is stacked on the negative current collector. The first barrier structure can reduce the transmission rate of lithium ions, so that the conductivity and the ability to intercalate and deintercalate lithium ions in the first region are lower than those in the second region, reducing the edge lithium deposition effect caused by lithium ion migration and cycle accumulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0022] Figure 1 is a cross-sectional schematic view of a battery according to an embodiment;

[0023] Figure 2 is a top view schematic view of a negative electrode sheet according to an embodiment;

[0024] Figure 3 is Figure 2 a cross-sectional schematic view taken at E-E in

[0025] Figure 4 is Figure 2 a cross-sectional schematic view taken at F-F in

[0026] Description of the reference numerals:

[0027] 100 - battery;

[0028] 10 - negative electrode sheet, 11 - negative current collector, 111 - first edge, 112 - fourth edge, 113 - seventh edge, 12 - negative active material layer, 121 - first region, 122 - second region, 123 - second edge, 124 - third edge, 125 - third region, 126 - fifth edge, 127 - sixth edge, 128 - fourth region, 129 - fifth region, 13 - first blocking structure, 131 - first side, 132 - second side, 14 - second blocking structure, 141 - third side, 142 - fourth side, 15 - third blocking structure, 16 - fourth blocking structure;

[0029] 20 - positive electrode sheet, 21 - positive current collector, 22 - positive active material layer;

[0030] 30 - separator;

[0031] D - first thickness, A1 - first distance, B1 - second distance, A2 - third distance, B2 - fourth distance, P - first dimension. Detailed implementation manners

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] It should be noted that when a component is referred to as being "fixed to" another component, it can be directly on the other component or there can also be an intermediate component. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intermediate component at the same time.

[0034] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the present invention in the specification are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The term "and / or" used in the present invention includes any and all combinations of one or more of the related listed items.

[0035] Next, some embodiments of the present invention will be described in detail in conjunction with the accompanying drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0036] An embodiment of the present invention provides an electrical device, including an electrical device and the battery in the embodiment of the present invention, and the battery supplies power to the electrical device.

[0037] Optionally, the electrical device can be an electric vehicle, a hybrid electric vehicle, a base station, a household electrical load, etc. The battery can be a power battery, an energy storage battery, etc., without specific limitation.

[0038] In one embodiment, the electrical device is an electric vehicle or a hybrid electric vehicle, and the battery is a power battery.

[0039] The electrical device uses the battery in the embodiment of the utility model, and the battery has good cycle performance and long service life.

[0040] Please refer to Figure 1 , the embodiment of the utility model further provides a battery 100, which includes a positive electrode plate 20 and a negative electrode plate 10 in the embodiment of the utility model or a negative electrode plate 10 prepared by the preparation method of the negative electrode plate 10 in the embodiment of the utility model.

[0041] Optionally, the battery 100 can be a stacked battery 100 or a wound battery 100. The stacked battery 100 is, for example, a square stacked battery 100, a blade stacked battery 100, etc., without limitation.

[0042] Optionally, the battery 100 further includes a housing (not shown in the figure). The housing includes a bottom plate and a plurality of side plates. The side plates are connected to the bottom plate and enclose to form a receiving cavity. One end of the receiving cavity opposite to the bottom plate is open, and the battery 100 is received in the receiving cavity.

[0043] Optionally, the housing is made of a material with high structural strength, specifically a metal material, a high-strength plastic, a ceramic, etc. The metal material is, for example, aluminum, aluminum alloy, magnesium alloy, iron and iron alloy, etc. The housing can be an integral structure, that is, the bottom plate and the side plates are an integral structure made by an integral molding process. The integral molding process can specifically be stamping, casting, etc., without limitation. The housing can also be a split structure, and the side plates and the bottom plate can be connected and fixed by welding, bonding, clamping, screwing, etc. The wall thickness of each part of the housing can be substantially uniform, that is, the thickness of the side plates can be substantially uniform and consistent, and the thickness of the bottom plate and the side plates can also be substantially the same.

[0044] Optionally, the battery 100 further includes a cover plate (not shown in the figure). The cover plate is connected to the opening of the housing to close the receiving cavity. The connection manner between the cover plate and the housing can be welding, bonding, clamping, screwing, etc., without limitation. The shape of the cover plate can be substantially the same as that of the bottom plate.

[0045] Optionally, the positive electrode sheet 20 includes a positive electrode current collector 21, and a positive electrode active material layer 22 is provided on at least one side of the positive electrode current collector 21. The positive electrode active material layer 22 includes components such as a positive electrode material, a conductive agent, and a binder. The present invention does not specifically limit these materials, and appropriate materials can be selected according to actual application requirements. The positive electrode current collector 21 includes, but is not limited to, any one of copper foil and aluminum foil. The positive electrode active material can be a phosphate positive electrode active material and a ternary positive electrode active material. In specific embodiments, it includes lithium cobaltate, lithium manganate, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium oxyphosphate, lithium fluorovanadate, lithium titanate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, binary material LiNi x A(1-k)O2 (where A is selected from one of Co and Mn, and 0 < k < 1), ternary material LiNi m E n M(1-i-j)O2 (where E and M are independently selected from at least one of Co, Al, and Mn, and E and M are different, 0 < i < 1, 0 < j < 1), or one or more of them. The conductive agent includes one or more of Super P, Super S, graphene, acetylene black, carbon fiber, Ketjen black, C60, and carbon nanotubes, and the content of the conductive agent in the positive electrode active material layer 22 is 3 wt% - 5 wt%. The types of binders include one or more of polyvinylidene chloride, soluble polytetrafluoroethylene, styrene-butadiene rubber, hydroxypropyl methylcellulose, methylcellulose, carboxymethylcellulose, polyvinyl alcohol, acrylonitrile copolymer, sodium alginate, chitosan, and chitosan derivatives, and the content of the binder in the positive electrode active material layer 22 is 2 wt% - 4 wt%.

[0046] Optionally, the negative electrode sheet 10 includes a negative electrode current collector 11, and a negative electrode active material layer 12 is provided on at least one side of the negative electrode current collector 11. The negative electrode active material layer 12 includes components such as a negative electrode material, a conductive agent, and a binder. The present invention does not specifically limit these materials, and appropriate materials can be selected according to actual application requirements. The negative electrode current collector 11 includes, but is not limited to, any one of copper foil, composite copper foil, or coated carbon copper foil. The negative electrode material includes, but is not limited to, carbon-based negative electrodes and silicon-based negative electrodes. Among them, the carbon-based negative electrode can include graphite, hard carbon, soft carbon, graphene, etc.; the silicon-based negative electrode can include silicon, silicon carbide, silicon oxide, silicon metal compounds, etc. In some specific embodiments, the above negative electrode material is selected from at least one of silicon monoxide, silicon carbide, and silicon-carbon composite. The conductive agent in the negative electrode active material layer 12 can improve the conductivity of the negative electrode material. The conductive agent can include one or more of acetylene black, Ketjen carbon black, SuperP, Super S, carbon nanotubes, carbon nanofibers, activated carbon, and graphene.

[0047] Optionally, the battery 100 further includes a separator 30, which can be any one of a woven film, a non-woven film (non-woven fabric), a microporous film, a composite film, a calendared film, etc., and can be selected according to actual application requirements without specific limitations.

[0048] Lithium-ion batteries 100 are widely used in energy storage and electric vehicles and other fields because of their high energy density, high average output voltage, high output power, low self-discharge, excellent cycling performance, fast charge and discharge, wide operating temperature range, long service life and other advantages.

[0049] The battery 100 in the embodiment of the present utility model can alleviate the edge lithium plating effect caused by lithium ion migration and cycle accumulation by adopting the negative electrode sheet 10 in the embodiment of the present utility model, effectively solve the problems of battery 100 capacity drop and safety caused by edge lithium plating, extend the life of the battery 100, and have good safety.

[0050] The following is a detailed introduction to the negative electrode sheet 10 in the embodiment of the present utility model.

[0051] First, define the direction. As Figure 1 and Figure 2 shown, X is the first direction, Y is the second direction, and the first direction X intersects with the second direction Y. Optionally, the first direction X is perpendicular to the second direction Y.

[0052] Please refer to Figure 2 and Figure 3 , the embodiment of the present utility model provides a negative electrode sheet 10, which includes a negative electrode current collector 11, a first blocking structure 13 and a negative electrode active material layer 12. The negative electrode current collector 11 includes a first edge 111 extending along the second direction Y. The first blocking structure 13 is laminated on the negative electrode current collector 11. The negative electrode active material layer 12 includes a first region 121 and a second region 122 arranged in sequence in the first direction X, and the first region 121 is closer to the first edge 111 than the second region 122. At least a part of the first region 121 is laminated on the first blocking structure 13, and the second region 122 is laminated on the negative electrode current collector 11. The first blocking structure 13 is adapted to reduce the ability of the first region 121 to deintercalate lithium ions compared to the ability of the second region 122 to deintercalate lithium ions.

[0053] Optionally, the first region 121 and the second region 122 are connected in the first direction X, or the first region 121 and the second region 122 have a gap in the first direction X, without specific limitations.

[0054] Optionally, the area of the first region 121 is smaller than the area of the second region 122.

[0055] Optionally, the battery 100 further includes a negative electrode tab, and the negative electrode tab is connected to the negative electrode sheet 10.

[0056] Optionally, the negative electrode ear can be in the form of a full-electrode ear, a multi-electrode ear or a single-electrode ear, etc. The output electrode ear can be in the form of the same-face output electrode ear, the different-face output electrode ear, the symmetrical output electrode ear or the asymmetrical output electrode ear, etc.

[0057] Optionally, in one embodiment, the negative electrode ear is connected to the first edge 111 ; or, the negative electrode ear is connected to an edge of the negative electrode current collector 11 adjacent to / opposite to the first edge 111 , and there is no specific limitation.

[0058] Optionally, in the orthographic projection of the positive electrode sheet 20 on the negative electrode sheet 10 , the edge of the positive electrode active material layer 22 of the positive electrode sheet 20 falls on the first region 121 of the negative electrode sheet 10 .

[0059] Lithium-ion batteries 100 are widely used in fields such as energy storage and electric vehicles because of their high energy density, high average output voltage, high output power, low self-discharge, excellent cycle performance, fast charge and discharge, wide operating temperature range, and long service life. Among them, the long charging time is the main obstacle to the further development of lithium-ion batteries 100. A key factor limiting the rapid charging of lithium-ion batteries 100 is that the negative electrode of the battery 100 is prone to lithium metal deposition on the surface during rapid charging. On the one hand, the deposited lithium metal reacts with the electrolyte, consuming the active lithium of the positive electrode, causing the capacity of the battery 100 to decay rapidly. On the other hand, the continued growth of lithium metal can easily pierce the diaphragm 30, causing serious safety problems.

[0060] In order to solve the problem of lithium metal precipitation, it is necessary to improve the design of the negative electrode sheet 10 of the battery 100. Current research has found that lithium precipitation behavior first occurs at the edge of the negative electrode sheet 10 close to the overhang. During the charge and discharge process, the active lithium at the edge of the negative electrode will diffuse to the overhang area, making the SOC of the negative electrode close to the edge lower than that in the middle during the charging process. The current density is too high at this position during the charging process, which leads to the occurrence of lithium precipitation.

[0061] The first barrier structure 13 can reduce the conductivity and lithium insertion and extraction activity of the first region, reduce the rate and proportion of lithium migration from the edge to the overhang, and reduce the SOC difference between the negative electrode edge and the overhang position, thereby effectively avoiding the occurrence of edge lithium deposition.

[0062] In the negative electrode sheet 10 in the embodiment of the present utility model, by arranging the first hindrance structure 13 to be stacked on the negative electrode current collector 11, the first region 121 of the negative electrode active material layer 12 is closer to the first edge 111 than the second region 122, and at least a part of the first region 121 is stacked on the first hindrance structure 13, the second region 122 is stacked on the negative electrode current collector 11, and the first hindrance structure 13 can reduce the transmission rate of lithium ions, so that the conductivity of the first region 121 and the ability to insert and extract lithium ions are lower than those of the second region 122, reducing the edge lithium plating effect caused by lithium ion migration and cycle accumulation.

[0063] Optionally, as Figure 3 shown, the thickness of the first hindrance structure 13 is the first thickness D, satisfying: 0.3 μm ≤ D ≤ 6 μm.

[0064] Optionally, the first thickness D of the first hindrance structure 13 satisfies: 0.5 μm ≤ D ≤ 5 μm.

[0065] Optionally, the value of the first thickness D can be 0.7 μm, 1 μm, 1.2 μm, 3 μm, 4 μm, etc., without specific limitation.

[0066] By arranging the first thickness D of the first hindrance structure 13 to satisfy 0.3 μm ≤ D ≤ 6 μm, the lithium insertion / extraction activity of the first region 121 can be reduced, and the edge lithium plating effect caused by lithium ion migration and cycle accumulation can be reduced.

[0067] Optionally, the first hindrance structure 13 is hydrated alumina and / or alumina parts.

[0068] Optionally, the first hindrance structure 13 is a hydrated alumina part, or the first hindrance structure 13 is an alumina part, or the first hindrance structure 13 is a combination part of hydrated alumina and alumina. The above methods are all acceptable and without specific limitation.

[0069] Optionally, the first hindrance structure 13 is formed by coating hydrated alumina and / or alumina slurry on the negative electrode current collector 11.

[0070] By arranging the first hindrance structure 13 to be hydrated alumina and / or alumina parts, the lithium insertion / extraction activity of the first region 121 can be reduced, and the edge lithium plating effect caused by lithium ion migration and cycle accumulation can be reduced.

[0071] Optionally, in one implementation manner, as Figure 3 shown, the surface of the first region 121 facing away from the first hindrance structure 13 is flush with the surface of the second region 122 facing away from the negative electrode current collector 11 to form a flat surface of the negative electrode sheet 10, which is convenient for assembly.

[0072] Optionally, in another embodiment, the thickness of the first region 121 is the same as that of the second region 122. Since at least part of the first region 121 is stacked on the first blocking structure 13, the first region 121 protrudes from the surface of the second region 122 facing away from the negative current collector 11.

[0073] Optionally, the first region 121 includes a second edge 123 close to the first edge 111 in the first direction X. In the first direction X, the distance from the first edge 111 to the second edge 123 is C1, satisfying: 0 mm ≤ C1 ≤ 2 mm.

[0074] Optionally, the negative current collector 11 can be rectangular, trapezoidal, parallelogram-shaped, etc., without specific limitation.

[0075] Optionally, the shape of the negative active material layer 12 corresponds to that of the negative current collector 11, and the stacking thicknesses of the first region 121 and the second region 122 on the negative current collector 11 are the same.

[0076] Exemplarily, as Figure 2 shown, the negative current collector 11, the first region 121, and the second region 122 are all rectangular.

[0077] Optionally, when the distance C1 from the first edge 111 to the second edge 123 is zero, the first edge 111 and the second edge 123 coincide, that is, the first region 121 is arranged from the first edge 111 of the negative current collector 11 to the other side of the negative current collector 11.

[0078] Optionally, when the distance C1 from the first edge 111 to the second edge 123 satisfies: 0 mm ≤ C1 ≤ 2 mm, there is a gap between the second edge 123 and the first edge 111, which is convenient for multiple coatings.

[0079] By setting that the first region 121 includes a second edge 123 opposite to the first edge 111 in the first direction X, and in the first direction X, the distance C1 from the first edge 111 to the second edge 123 satisfies: 0 mm ≤ C1 ≤ 2 mm, the processing is convenient.

[0080] Optionally, the first region 121 includes a second edge 123 and a third edge 124 opposite to each other in the first direction X. The second edge 123 is close to the first edge 111, and the third edge 124 is connected to the second region 122. In the first direction X, the first blocking structure 13 is located between the first edge 111 and the third edge 124.

[0081] By arranging the first barrier structure 13 between the first edge 111 and the third edge 124, at least a portion of the first region 121 is stacked with the first barrier structure 13, and the first barrier structure 13 can reduce the conductivity and lithium insertion and extraction activity of the first region 121, thereby reducing the edge lithium deposition effect caused by lithium ion migration and cycle accumulation.

[0082] Optionally, the first blocking structure 13 includes a first side 131 and a second side 132 that are opposite to each other in the first direction X, and the first side 131 is closer to the first edge 111 than the second side 132 .

[0083] Optionally, the first edge 131 may overlap with the first edge 111; or, the first edge 131 is located between the first edge 111 and the second edge 123; or, the first edge 131 overlaps with the second edge 123; or, the first edge 131 is located between the second edge 123 and the third edge 124, without specific limitation.

[0084] Optionally, the second side 132 is closer to the third edge 124 than the first side 131. The second side 132 may overlap with the third edge 124, or the second side 132 may be located between the second edge 123 and the third edge 124, which is not specifically limited.

[0085] The different positions of the first edge 131 and the second edge 132 may be arranged in any combination, so that at least a portion of the first region 121 is stacked with the first blocking structure 13 .

[0086] Optional, such as Figure 2 As shown, in the first direction X, the distance from the first side 131 to the first edge 111 is a first distance A1, which satisfies: 0 mm ≤ A1 ≤ 2 mm.

[0087] Optionally, the first barrier structure 13 is block-shaped, and the first barrier structure 13 is rectangular in the orthographic projection of the negative electrode current collector 11 .

[0088] Optionally, when the first distance A1 from the first side 131 to the first edge 111 is zero, the first side 131 and the first edge 111 coincide with each other, that is, the first blocking structure 13 extends from the first edge 111 of the negative electrode current collector 11 in the first direction X to the other side of the negative electrode current collector 11 opposite to the first edge 111 .

[0089] Optionally, when the first distance A1 from the first side 131 to the first edge 111 satisfies: 0 mm<A1≤2 mm, there is a gap between the first side 131 and the first edge 111 to facilitate multiple coatings.

[0090] Optionally, in one embodiment, as Figure 2 As shown, the first edge 131 coincides with the second edge 123 , ie, A1 = C1 .

[0091] By setting the first distance A1 from the first side 131 to the first edge 111 in the first direction X to satisfy 0 mm ≤ A1 ≤ 2 mm, the processing is convenient.

[0092] Optionally, as Figure 3 shown, the distance from the first side 131 to the second side 132 is the second distance B1, satisfying: 1 mm ≤ B1 ≤ 10 mm.

[0093] Optionally, the second distance B1 from the first side 131 to the second side 132 satisfies: 3 mm ≤ B1 ≤ 7 mm.

[0094] Optionally, the value of the second distance B1 can be 3 mm, 5 mm, 6 mm, 7 mm, etc., without specific limitation.

[0095] By setting the first blocking structure 13 to include the first side 131 and the second side 132 opposite to each other in the first direction X, and the second distance B1 from the first side 131 to the second side 132 to satisfy 1 mm ≤ B1 ≤ 10 mm, the first blocking structure 13 can reduce the lithium insertion / extraction activity in the first region 121 and reduce the edge lithium plating effect caused by lithium ion migration and cycle accumulation. With appropriate dimensions of the first blocking structure 13, while effectively reducing the lithium insertion / extraction activity at the edge of the negative electrode sheet 10, the negative electrode sheet 10 still maintains good electrical conductivity.

[0096] Optionally, as Figure 3 shown, the negative electrode sheet 10 further includes a second blocking structure 14. The second blocking structure 14 is laminated on the negative electrode current collector 11. The negative electrode active material layer 12 further includes a third region 125. The third region 125 is located on the side of the second region 122 facing away from the first region 121 in the first direction X, and at least a part of the third region 125 is laminated on the second blocking structure 14. The second blocking structure 14 is adapted to reduce the ability of the third region 125 to insert / extract lithium ions compared to the ability of the second region 122 to insert / extract lithium ions.

[0097] Optionally, the third region 125 is rectangular, and the area of the third region 125 is the same as the area of the first region 121.

[0098] Optionally, the third region 125 and the second region 122 are connected in the first direction X, or there is a gap between the third region 125 and the second region 122 in the first direction X, without specific limitation.

[0099] By providing that the negative electrode sheet 10 further includes a second blocking structure 14 laminated on the negative electrode current collector 11, the negative electrode active material layer 12 further includes a third region 125 on the side of the second region 122 facing away from the first region 121, and at least a part of the third region 125 is laminated on the second blocking structure 14, the third blocking structure 15 can reduce the ability of the third region 125 to insert and extract lithium ions, thereby reducing the amount of lithium deposition in the third region 125 and reducing the occurrence of edge lithium deposition.

[0100] Optionally, the thickness of the second blocking structure 14 corresponds to that of the aforementioned first blocking structure 13 for reference. The second blocking structure 14 is also a hydrated alumina and / or alumina member, and details are not described herein again.

[0101] Optionally, the negative electrode current collector 11 further includes a fourth edge 112 opposite to the first edge 111 in the first direction X. The third region 125 includes a fourth edge 112 and a fifth edge 126 opposite to each other in the first direction X. The fifth edge 126 is close to the fourth edge 112, and a sixth edge 127 is connected to the second region 122. In the first direction X, the second blocking structure 14 is located between the fourth edge 112 and the sixth edge 127.

[0102] Optionally, the fourth edge 112 can be connected to the negative electrode tab. In one embodiment, the negative electrode sheet 10 includes two negative electrode tabs, and the two negative electrode tabs are respectively connected to the first edge 111 and the fourth edge 112. The tabs can be half tabs or full tabs, without limitation.

[0103] Optionally, the third region 125 is also rectangular, and the thickness of the third region 125 is the same as the lamination thickness of the first region 121 on the negative electrode current collector 11.

[0104] By providing that the second blocking structure 14 is located between the fourth edge 112 and the sixth edge 127, at least a part of the third region 125 is laminated with the second blocking structure 14. The second blocking structure 14 can reduce the conductivity and lithium insertion / extraction activity of the third region 125, and reduce the edge lithium deposition effect caused by lithium ion migration and cycle accumulation.

[0105] Optionally, the second blocking structure 14 includes a third side 141 and a fourth side 142 opposite to each other in the first direction X. The third side 141 is closer to the fourth edge 112 than the fourth side 142.

[0106] Optionally, the third side 141 can coincide with the fourth edge 112; or, the third side 141 is located between the fourth edge 112 and the fifth edge 126; or, the third side 141 coincides with the fifth edge 126; or, the third side 141 is located between the fifth edge 126 and the sixth edge 127, without specific limitation.

[0107] Optionally, the fourth side 142 is closer to the sixth edge 127 than the third side 141. The fourth side 142 may coincide with the sixth edge 127, or the fourth side 142 may be located between the fifth edge 126 and the sixth edge 127, without specific limitation.

[0108] The above different position settings of the third side 141 and the fourth side 142 can be arbitrarily arranged and combined so that at least part of the third region 125 is stacked with the second blocking structure 14.

[0109] Optionally, in the first direction X, the distance from the third side 141 to the fourth edge 112 is the third distance A2, satisfying: 0 mm ≤ A2 ≤ 2 mm.

[0110] Optionally, in one embodiment, as Figure 2 shown, the third side 141 coincides with the fifth edge 126, and the third distance A2 from the third side 141 to the fourth edge 112 is the same as the distance from the fifth edge 126 to the fourth edge 112.

[0111] By setting the third distance A2 from the third side 141 to the fourth edge 112 in the first direction X to satisfy 0 mm ≤ A2 ≤ 2 mm, the processing is convenient.

[0112] Optionally, the distance from the third side 141 to the fourth side 142 is the fourth distance B2, satisfying: 1 mm ≤ B2 ≤ 10 mm.

[0113] Optionally, in one embodiment, as Figure 3 shown, the third side 141 coincides with the fifth edge 126, and the fourth side 142 coincides with the sixth edge 127.

[0114] Optionally, the fourth distance B2 from the third side 141 to the fourth side 142 satisfies: 3 mm ≤ B2 ≤ 7 mm.

[0115] Optionally, the value of the fourth distance B2 can be 3 mm, 5 mm, 6 mm, 7 mm, etc., without specific limitation.

[0116] By setting the second blocking structure 14 to include the third side 141 and the fourth side 142 opposite to each other in the first direction X, and the fourth distance B2 from the third side 141 to the fourth side 142 satisfies 1 mm ≤ B2 ≤ 10 mm, the second blocking structure 14 can reduce the intercalation and deintercalation lithium activity of the third region 125 and reduce the edge lithium deposition effect caused by lithium ion migration and cycle accumulation. The size of the second blocking structure 14 is appropriate, and while effectively reducing the intercalation and deintercalation lithium activity at the edge of the negative electrode sheet 10, the good electrical conductivity of the negative electrode sheet 10 is still maintained.

[0117] Optionally, as Figure 4As shown, the negative electrode sheet 10 further includes a third blocking structure 15 which is stacked on the negative electrode current collector 11. The negative electrode current collector 11 further includes a seventh edge 113 adjacent to the first edge 111. The negative electrode active material layer 12 further includes a fourth region 128. The fourth region 128 and the second region 122 are arranged in sequence in the second direction Y, and the fourth region 128 is closer to the seventh edge 113 than the second region 122. The second direction Y intersects with the first direction X. At least a part of the fourth region 128 is stacked on the third blocking structure 15, and the third blocking structure 15 is adapted to reduce the ability of the fourth region 128 to intercalate and deintercalate lithium ions compared with the ability of the second region 122 to intercalate and deintercalate lithium ions.

[0118] Optionally, the second direction Y is perpendicular to the first direction X.

[0119] Optionally, the fourth region 128 is rectangular, and the area size of the fourth region 128 may be the same as or different from the area sizes of the first region 121 and the third region 125, and no specific limitation is made.

[0120] Optionally, the fourth region 128 and the second region 122 are connected in the second direction Y, or there is a gap between the fourth region 128 and the second region 122 in the second direction Y, and no specific limitation is made.

[0121] Optionally, the negative electrode tab can also be connected to the seventh edge 113, and the connection method is not specifically limited.

[0122] By providing that the negative electrode sheet 10 further includes a third blocking structure 15 stacked on the negative electrode current collector 11, the negative electrode current collector 11 further includes a seventh edge 113 adjacent to the first edge 111, the fourth region 128 and the second region 122 of the negative electrode active material layer 12 are arranged in sequence in the second direction Y, and at least a part of the fourth region 128 closer to the seventh edge 113 is stacked on the third blocking structure 15, the third blocking structure 15 can reduce the conductivity and the lithium intercalation / deintercalation activity of the fourth region 128, and reduce the edge lithium plating effect caused by lithium ion migration and cycle accumulation.

[0123] Similarly, the positional relationship between the fourth region 128 and the third blocking structure 15 is similar to the positional relationship between the first region 121 and the first blocking structure 13 described above, and can be referred to without further elaboration.

[0124] Optionally, the negative electrode active material layer 12 further includes a fifth region 129. The fifth region 129 is located on the side of the second region 122 facing away from the fourth region 128 in the second direction Y. The negative electrode sheet 10 further includes a fourth blocking structure 16. At least a part of the fifth region 129 is stacked on the fourth blocking structure 16, and the fourth blocking structure 16 is adapted to reduce the ability of the fifth region 129 to intercalate and deintercalate lithium ions compared with the ability of the second region 122 to intercalate and deintercalate lithium ions.

[0125] Optionally, the negative electrode sheet 10 includes any one or a combination of a first blocking structure 13, a second blocking structure 14, a third blocking structure 15, and a fourth blocking structure 16; the negative electrode active material layer 12 includes a second region 122 and any one or a combination of a first region 121, a third region 125, a fourth region 128, and a fifth region 129, and there is no specific limitation.

[0126] In one embodiment, as Figure 2 、 Figure 3 and Figure 4 shown, the negative electrode active material layer 12 includes a first region 121, a second region 122, a third region 125, a fourth region 128, and a fifth region 129, and the negative electrode sheet 10 includes corresponding first, second, third, and fourth blocking structures 13, 14, 15, and 16.

[0127] Optionally, the negative electrode sheet 10 includes an overlapping region and an overhang region. The overlapping region is adapted to overlap with the positive electrode active material layer 22 of the positive electrode sheet 20, and the overhang region includes at least a part of the first region 121.

[0128] Optionally, as Figure 1 shown, the overhang region may include all of the first region 121 or a part of the first region 121, and there is no specific limitation. In the first direction X, the size of the overhang region is a first size P, satisfying: 1 mm ≤ P ≤ 3 mm.

[0129] Optionally, the first size P may be 1 mm, 2 mm, 3 mm, etc., without limitation.

[0130] Setting the first size P of the overhang region to satisfy 1 mm ≤ P ≤ 3 mm can ensure the battery performance while preventing lithium deposition on the negative electrode sheet 10.

[0131] By providing that the negative electrode sheet 10 includes an overlapping region and an overhang region, the overhang region can prevent lithium deposition on the negative electrode sheet 10 and improve the usage safety of the battery 100.

[0132] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0133] The above-disclosed is only a preferred embodiment of the present utility model. Of course, it cannot be used to limit the scope of rights of the present utility model. Those of ordinary skill in the art can understand all or part of the processes of implementing the above embodiments, and the equivalent changes made according to the claims of the present utility model still fall within the scope covered by the present utility model.

Claims

1. A negative electrode sheet, characterized in that: include: a negative electrode current collector including a first edge; A first barrier structure is stacked on the negative electrode current collector; A negative electrode active material layer comprises a first region and a second region arranged in sequence in a first direction, wherein the first region is closer to the first edge than the second region, the first edge extends along a second direction, and the second direction intersects with the first direction; at least a portion of the first region is stacked on the first obstruction structure, and the second region is stacked on the negative electrode current collector, and the first obstruction structure is suitable for reducing the ability of the first region to deintercalate lithium ions compared to the ability of the second region to deintercalate lithium ions.

2. The negative electrode sheet according to claim 1, characterized in that: The thickness of the first barrier structure is a first thickness D, which satisfies: 0.3 μm≤D≤6 μm.

3. The negative electrode sheet according to claim 1, characterized in that: The first obstruction structure is hydrated aluminum oxide and / or an aluminum oxide piece.

4. The negative electrode sheet according to claim 1, characterized in that: A surface of the first region facing away from the first barrier structure is flush with a surface of the second region facing away from the negative electrode current collector.

5. The negative electrode sheet according to any one of claims 1 to 4, characterized in that: The first region includes a second edge and a third edge opposite to each other in a first direction, the second edge is close to the first edge, the third edge is connected to the second region, and in the first direction, the first blocking structure is located between the first edge and the third edge.

6. The negative electrode sheet according to any one of claims 1 to 4, characterized in that: The first obstruction structure includes a first side and a second side opposite to each other in the first direction, the first side is closer to the first edge than the second side, and in the first direction, a distance from the first side to the first edge is A1, satisfying: 0mm≤A1≤2mm.

7. The negative electrode sheet according to any one of claims 1 to 4, characterized in that: The first obstruction structure includes a first side and a second side opposite to each other in the first direction, the first side is closer to the first edge than the second side, and a distance from the first side to the second side is B1, satisfying: 1mm≤B1≤10mm.

8. The negative electrode sheet according to any one of claims 1 to 4, characterized in that: The negative electrode sheet also includes a second barrier structure, which is stacked on the negative electrode current collector. The negative electrode active material layer also includes a third region, which is located on the side of the second region facing away from the first region in the first direction, and at least a portion of the third region is stacked on the second barrier structure, and the second barrier structure is suitable for reducing the ability of the third region to deintercalate lithium ions compared to the ability of the second region to deintercalate lithium ions.

9. The negative electrode sheet according to claim 8, characterized in that: The negative electrode current collector also includes a fourth edge opposite to the first edge in the first direction, the third region includes a fifth edge and a sixth edge opposite to each other in the first direction, the fifth edge is close to the fourth edge, the sixth edge is connected to the second region, and in the first direction, the second obstructing structure is located between the fourth edge and the sixth edge.

10. The negative electrode sheet according to any one of claims 1 to 4, characterized in that: The negative electrode sheet further includes a third barrier structure, the third barrier structure is stacked on the negative electrode current collector, the negative electrode current collector further includes a seventh edge adjacent to the first edge, the negative electrode active material layer further includes a fourth region, the fourth region and the second region are arranged in sequence in a second direction, and the fourth region is closer to the seventh edge than the second region, and the second direction intersects with the first direction; At least a portion of the fourth region is stacked on the third barrier structure, and the third barrier structure is adapted to reduce the ability of the fourth region to deintercalate lithium ions compared to the ability of the second region to deintercalate lithium ions.

11. The negative electrode sheet according to claim 1, characterized in that: The negative electrode sheet includes an overlap region and an overhang region, the overlap region is suitable for overlapping with the positive electrode active material layer of the positive electrode sheet, and the overhang region includes at least a portion of the first region.

12. The negative electrode sheet according to claim 11, characterized in that: The size of the overhang area in the first direction is a first size P, which satisfies: 1 mm ≤ P ≤ 3 mm.

13. A battery, characterized in that: The invention comprises a positive electrode sheet and the negative electrode sheet as claimed in any one of claims 1 to 12, wherein in the orthographic projection of the positive electrode sheet onto the negative electrode sheet, an edge of the positive electrode active material layer of the positive electrode sheet falls within the first region.

14. An electrical device, characterized in that: It comprises an electric device and the battery as claimed in claim 13, wherein the battery supplies power to the electric device.

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