Battery electrode sheet, battery, and electric device

Abstract

A battery electrode sheet. The battery electrode sheet comprises: a current collector (1), a first primer layer (3), a first insulating layer (2), a first active material layer (4), and a second active material layer (7), wherein the first primer layer (3) and the first insulating layer (2) are arranged side by side on one side of the current collector (1), the edge of the first primer layer (3) abuts against the edge of the first insulating layer (2), the area of the first insulating layer (2) at an abutting position is a thinned region (23), and the thickness of the thinned region (23) of the first insulating layer (2) is equal to the thickness of the first primer layer (3). Since the thickness of the thinned region (23) of the first insulating layer (2) is equal to the thickness of the first primer layer (3), the problem of a low battery capacity is avoided, intercalation and deintercalation of lithium ions during charging and discharging are not affected, the problem of lithium plating of a battery is avoided, and the problem of brittle fracture of an electrode sheet is avoided.

Description

Battery electrode, battery and power-consuming device

[0001] This application is based on the Chinese invention application with application number 202410025462.2 filed on January 8, 2024, entitled “A battery electrode, a battery and an electrical device”, and claims priority. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a battery electrode, a battery, and an electrical device. Background Art

[0003] As shown in Figures 1-2, the prior art requires that the thickness of the insulating layer on both sides of the electrode must be greater than the thickness of the bottom coating on the same side. However, when this electrode structure design is used to coat the active material layer on an extrusion coating device, the extrusion coating device controls the surface density of the active material layer by applying the slurry liquid at a certain pressure and a certain flow rate Q along the coating die outlet gap and the gap d between the coating die and the substrate. When the active material layer is coated on the side close to the coating die outlet, the thickness of the insulating layer on the side away from the coating die outlet is greater than the thickness of the bottom coating layer, resulting in a smaller coating weight of the active material layer in the area opposite to the insulating layer, causing low battery capacity and low energy density. At the same time, since the thickness of the insulating layer on the side away from the coating die outlet is greater than the thickness of the bottom coating layer, the rolling pressure in this area is relatively large, resulting in an excessively large compaction density of the active material layer in this area, affecting the insertion and extraction of lithium ions during charging and discharging, causing lithium plating problems in the battery, and also causing brittle fracture of the electrode. Therefore, how to overcome the above-mentioned technical problems and defects has become a key issue that needs to be solved.

[0004] Application Contents

[0005] In order to address the problem that the thickness of the existing electrode insulation layer is greater than the thickness of the base coating, resulting in low battery capacity density, and the insertion and extraction of lithium ions during charging and discharging easily trigger lithium deposition in the battery, causing brittle fracture of the electrode, the present application provides a battery electrode, a battery and an electrical device.

[0006] The technical solutions adopted by this application to solve the above technical problems are as follows:

[0007] On the one hand, the present application provides a battery electrode, comprising: a current collector, a first primer layer and a first insulating layer, a first active material layer and a second active material layer; the first primer layer and the first insulating layer are arranged side by side on one side of the current collector, the edge of the first primer layer and the edge of the first insulating layer abut each other, the area of ​​the first insulating layer at the abutting position is a thinning area, the thickness of the thinning area is less than the average thickness of the first insulating layer at the non-abutting position, the thickness of the thinning area of ​​the first insulating layer is flush with the thickness of the first primer layer, the first active material layer is arranged on the side of the first primer layer away from the current collector, the second active material layer is arranged on the other side of the current collector, and the projection of the second active material layer on the current collector covers the thinning area and the projection of the first primer layer on the current collector.

[0008] Optionally, a second primer layer and a second insulating layer are provided side by side on the other side of the current collector, the edge of the second primer layer and the edge of the second insulating layer abut against each other, and the thickness of the second insulating layer in the abutting area is greater than the thickness of the second primer layer.

[0009] Optionally, the second active material layer is provided on a surface of the second primer layer away from the current collector, and the second active material layer is not in contact with the second insulating layer.

[0010] Optionally, in the length direction of the current collector, the current collector includes a first end and a second end, the first insulating layer extends from the first end of the current collector to a position of the current collector close to the second end, and the first primer layer is located at the second end of the current collector; the second insulating layer is located at the first end of the current collector, and the second primer layer extends from the second end of the current collector to a position of the current collector close to the first end.

[0011] Optionally, in the length direction of the current collector, the first insulating layer includes a third end and a fourth end, the first primer layer includes a fifth end and a sixth end, the fourth end of the first insulating layer is provided with a thinning area, and the thinning area and the fifth end of the first primer layer abut each other.

[0012] Optionally, in the thickness direction of the pole piece, the thickness of the third end of the first insulating layer is Ta, and the thickness range of Ta is 3 to 15um; the thickness of the thinning area of ​​the fourth end of the first insulating layer is Tb, and the thickness range of Tb is 2 to 10um, the thickness of the first primer layer is Tc, and the thickness range of Tc is 2 to 10um; the thickness of the second insulating layer is Td, and the thickness range of Td is 3 to 15um, the thickness of the second primer layer is Te, and the thickness range of Te is 2 to 10um.

[0013] Optionally, in the thickness direction of the electrode, the thickness of the first active material layer is Tf, and the thickness range of Tf is 30 to 100 um; the thickness of the second active material layer is Tg, and the thickness range of Tg is 30 to 100 um.

[0014] Optionally, in the length direction of the current collector, the first active material layer includes a seventh end and an eighth end, and a gap is provided between the seventh end of the first active material layer and the fourth end of the first insulating layer, and the length of the gap is L1, and L1 satisfies: 0mm≤L1≤5mm; the second insulating layer includes a ninth end and a tenth end, the second active material layer includes an eleventh end and a twelfth end, and a gap is provided between the tenth end of the second insulating layer and the eleventh end of the second active material layer, and the length of the gap is L2, and L2 satisfies: 0mm≤L2≤5mm.

[0015] On the other hand, the present application provides a battery, comprising an electrolyte, a separator and the above-mentioned electrode sheets, wherein the electrode sheets include positive electrode sheets and / or negative electrode sheets.

[0016] On the other hand, the present application provides an electrical device including the battery described above.

[0017] According to the battery electrode provided in the present application, by making the thickness of the thinned area of ​​the first insulating layer equal to the thickness of the first primer layer, the coating weight of the second active material layer on the other side of the battery electrode is moderate, and therefore, the problem of low battery capacity will not be caused. At the same time, since the thickness of the thinned area of ​​the first insulating layer is equal to the thickness of the first primer layer, the rolling pressure in the second active material layer area is moderate, and the compaction density of the second active material layer in this area is moderate, which will not affect the insertion and extraction of lithium ions during the charge and discharge process, will not cause the problem of lithium plating of the battery, and will not cause the problem of brittle fracture of the electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a schematic diagram of the cross-sectional structure of an existing battery electrode;

[0019] FIG2 is a schematic diagram of the coating structure of an existing battery electrode;

[0020] FIG3 is a schematic diagram of the cross-sectional structure of a battery electrode provided by an embodiment of the present invention;

[0021] FIG4 is a schematic diagram of a coating structure of a battery electrode provided by an embodiment of the present invention;

[0022] FIG5 is a schematic diagram of a cross-sectional structure of an electrode group in the thickness direction according to an embodiment of the present invention;

[0023] The reference numerals in the drawings of the specification are as follows: 1-current collector; 11-first end; 12-second end; 2-first insulating layer; 21-third end; 22-fourth end; 23-thinning area; 3-first primer layer; 31-fifth end; 32-sixth end; 4-first active material layer; 41-seventh end; 42-eighth end; 5-second insulating layer; 51-ninth end; 52-tenth end; 6-second primer layer; 7-second active material layer; 71-eleventh end; 72-twelfth end; 8-coating die; 9-positive electrode Pole piece; 91-positive electrode current collector; 92-positive electrode insulating layer; 921-first positive electrode insulating layer; 922-second positive electrode insulating layer; 923-first thinning area; 93-positive electrode base coating; 931-first positive electrode base coating; 932-second positive electrode base coating; 94-positive electrode active material layer; 941-first positive electrode active material layer; 942-second positive electrode active material layer; 10-negative electrode piece; 101-negative electrode current collector; 102-negative electrode active material layer; 11-diaphragm. DETAILED DESCRIPTION

[0024] In order to make the technical problems, technical solutions and beneficial effects solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0025] In the description of this application, it should be understood that the terms "lateral," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0026] In the description of this application, it should be noted that, unless otherwise specified or limited, the term "connection" should be understood in a broad sense. For example, it can mean a fixed connection, a detachable connection, or an integral connection; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean internal communication between two components. For those skilled in the art, the specific meanings of the above terms in this application can be understood by those skilled in the art in specific circumstances.

[0027] As shown in Figures 3-4, in one embodiment, the present application provides a battery electrode sheet on one hand, including: a current collector 1, a first primer layer 3, a first insulating layer 2, a first active material layer 4 and a second active material layer 7; the first primer layer 3 and the first insulating layer 2 are arranged side by side on one side of the current collector 1, the edge of the first primer layer 3 and the edge of the first insulating layer 2 are abutted, the area of ​​the first insulating layer 2 at the abutting position is a thinning area 23, the thickness of the thinning area 23 is less than the average thickness of the first insulating layer 2 at the non-abutting position, the thickness of the thinning area 23 of the first insulating layer 2 is flush with the thickness of the first primer layer 3, the first active material layer 4 is arranged on the side of the first primer layer 3 away from the current collector 1, the second active material layer 7 is arranged on the other side of the current collector 1, and the projection of the second active material layer 7 on the current collector 1 covers the thinning area 23 and the projection of the first primer layer 3 on the current collector 1.

[0028] Specifically, when the battery electrode of the present application is coated with the second active material layer 7 on the extrusion coating equipment, one side of the battery electrode of the present application is close to the coating die 8, and the other side of the battery electrode of the present application is close to the coating roller. The extrusion coating equipment is to control the surface density of the second active material layer 7 by passing the slurry liquid along the outlet gap of the coating die 8 and the gap d between the coating die 8 and the substrate under a certain pressure and a certain flow rate Q. The thickness of the thinning area 23 of the first insulating layer 2 of the present application is flush with the thickness of the first primer layer 3, resulting in a moderate coating weight of the first active material layer 4 on the other side of the battery electrode. Therefore, it will not cause the problem of low battery capacity. At the same time, since the thickness of the thinning area 23 of the first insulating layer 2 is equal to the thickness of the first primer layer 3, the rolling pressure in this area is moderate, and the compaction density of the second active material layer 7 in this area is moderate, which will not affect the insertion and extraction of lithium ions during charging and discharging, will not cause lithium plating problems in the battery, and will not cause brittle fracture of the electrode.

[0029] As shown in Figures 3-4, in one embodiment, a second primer layer 6 and a second insulating layer 5 are provided side by side on the other side of the current collector 1, the edge of the second primer layer 6 and the edge of the second insulating layer 5 abut against each other, and the thickness of the second insulating layer 5 at the abutting position is greater than the thickness of the second primer layer 6.

[0030] The thickness of the second insulating layer 5 is greater than that of the second primer layer 6. The second insulating layer 5 provides an ion diffusion path but insulates electrons, does not affect the active material capacity of the area coated with the second active material layer 7, avoids battery short circuit, and improves the battery energy density while reducing the lithium ion transmission resistance during charging and discharging, and reduces the risk of lithium plating in the electrode area.

[0031] As shown in FIG3-4 , in one embodiment, the second active material layer 7 is disposed on a surface of the second primer layer 6 away from the current collector 1 , and the second active material layer 7 is not in contact with the second insulating layer 5 .

[0032] Specifically, since the second active material layer 7 covers the surface of the second primer layer 6, the second primer layer 6 is difficult to fall off even under a highly destructive external force such as nail penetration or impact, so that the current collector 1 will not leak, making its electrode assembly safer.

[0033] Furthermore, the second active material layer 7 does not contact the second insulating layer 5, avoiding overlapping with the second insulating layer 5, thereby causing the thickness of the tenth end 52 of the second insulating layer 5 on the other side of the current collector 1 to be too thick, resulting in the coating weight of the second active material layer 7 on the other side of the current collector 1 being too small, causing the battery capacity to be low.

[0034] As shown in Figures 3-4, in one embodiment, in the length direction of the current collector 1, the current collector 1 includes a first end 11 and a second end 12, the first insulating layer 2 extends from the first end 11 of the current collector 1 to a position of the current collector 1 close to the second end 12, and the first primer layer 3 is located at the second end 12 of the current collector 1; the second insulating layer 5 is located at the first end of the current collector 1, and the second primer layer 6 extends from the second end of the current collector 1 to a position of the current collector 1 close to the first end.

[0035] Specifically, the first insulating layer 2 is located at the first end 11 of the current collector 1, and the first primer layer 3 is located at the second end 12 of the current collector 1. The thinning area 23 of the first insulating layer 2 is abutted against the end of the first primer layer 3. The thickness of the thinning area 23 of the first insulating layer 2 of the present application is equal to the thickness of the first primer layer 3, resulting in a moderate coating weight of the first active material layer 4 on the other side of the battery electrode. Therefore, it will not cause the problem of low battery capacity; and the first insulating layer 2 and the first primer layer 3 completely cover the surface of the electrode, and there is no gap in the length direction of the electrode, so that the current collector 1 is not easily exposed when it is impacted or punctured by external force.

[0036] As shown in Figures 3-4, in one embodiment, in the length direction of the current collector 1, the first insulating layer 2 includes a third end 21 and a fourth end 22, the first primer layer 3 includes a fifth end 31 and a sixth end 32, and the fourth end 22 of the first insulating layer 2 is provided with a thinning area 23, and the thinning area 23 and the fifth end 31 of the first primer layer 3 abut each other.

[0037] Specifically, the fourth end 22 of the first insulating layer 2 is provided with a thinning area 23, and the thinning area 23 and the fifth end 31 of the first primer layer 3 abut each other. The thickness of the thinning area 23 of the first insulating layer 2 of the present application is equal to the thickness of the first primer layer 3, resulting in a moderate coating weight of the first active material layer 4 on the other side of the battery electrode, and therefore will not cause the problem of low battery capacity; and, the first insulating layer 2 and the first primer layer 3 completely cover the surface of the electrode, and there is no gap in the length direction of the electrode, so the collector 1 is better insulated and isolated, and therefore has higher safety performance.

[0038] Furthermore, the length of the thinning zone 23 depends on the width and thickness of the battery. When the width of the battery is narrower and / or the thickness of the battery is thinner, the length of the thinning zone 23 is shorter; conversely, when the width of the battery is longer and / or the thickness of the battery is thicker, the length of the thinning zone 23 is longer.

[0039] As shown in Figures 3-4, in one embodiment, in the thickness direction of the pole piece, the thickness of the third end 21 of the first insulating layer 2 is Ta, and the thickness range of Ta is 3 to 15um; the thickness of the thinning area 23 of the fourth end 22 of the first insulating layer 2 is Tb, and the thickness range of Tb is 2 to 10um, the thickness of the first primer layer 3 is Tc, and the thickness range of Tc is 2 to 10um; the thickness of the second insulating layer 5 is Td, and the thickness range of Td is 3 to 15um, the thickness of the second primer layer 6 is Te, and the thickness range of Te is 2 to 10um.

[0040] In a preferred embodiment, the thickness of the third end 21 of the first insulating layer 2 is 5 to 10 um; for example, a range consisting of any two of 3 um, 4 um, 5 um, 6 um, 7 um, 8 um, 9 um, 10 um, 11 um, 12 um, 13 um, 14 um or 15 um.

[0041] In a preferred embodiment, the thickness of the thinned region 23 at the fourth end 22 of the first insulating layer 2 is 5 to 8 um; for example, a range consisting of any two of 2 um, 3 um, 4 um, 5 um, 6 um, 7 um, 8 um, 9 um or 10 um.

[0042] In a preferred embodiment, the thickness of the first primer layer 3 is 5 to 8 um; for example, a range consisting of any two of 2 um, 3 um, 4 um, 5 um, 6 um, 7 um, 8 um, 9 um or 10 um.

[0043] In a preferred embodiment, the thickness of the second insulating layer 5 is 5 to 10 um; for example, a range consisting of any two of 3 um, 4 um, 5 um, 6 um, 7 um, 8 um, 9 um, 10 um, 11 um, 12 um, 13 um, 14 um or 15 um.

[0044] In a preferred embodiment, the thickness of the second primer layer 6 is 5 to 8 um; for example, a range consisting of any two of 2 um, 3 um, 4 um, 5 um, 6 um, 7 um, 8 um, 9 um or 10 um.

[0045] As shown in FIG3-4 , in one embodiment, in the thickness direction of the electrode, the thickness of the first active material layer 4 is Tf, and the thickness range of Tf is 30 to 100 um; the thickness of the second active material layer 7 is Tg, and the thickness range of Tg is 30 to 100 um.

[0046] In a preferred embodiment, the thickness of the first active material layer 4 is 50 to 80 um; for example, a range consisting of any two of 30 um, 35 um, 90 um, 45 um, 50 um, 55 um, 60 um, 65 um, 70 um, 75 um, 80 um, 85 um, 90 um, 95 um or 100 um.

[0047] In a preferred embodiment, the thickness of the second active material layer 7 is 50 to 80 um; for example, a range consisting of any two of 30 um, 35 um, 90 um, 45 um, 50 um, 55 um, 60 um, 65 um, 70 um, 75 um, 80 um, 85 um, 90 um, 95 um or 100 um.

[0048] As shown in Figures 3-4, in one embodiment, in the length direction of the current collector 1, the first active material layer 4 includes a seventh end 41 and an eighth end 42, and a gap is provided between the seventh end 41 of the first active material layer 4 and the fourth end 22 of the first insulating layer 2, and the length of the gap is L1, and L1 satisfies: 0mm≤L1≤5mm; the second insulating layer 5 includes a ninth end 51 and a tenth end 52, and the second active material layer 7 includes an eleventh end 71 and a twelfth end 72, and a gap is provided between the tenth end 52 of the second insulating layer 5 and the eleventh end 71 of the second active material layer 7, and the length of the gap is L2, and L2 satisfies: 0mm≤L2≤5mm.

[0049] In some embodiments, the distance between the edge of the seventh end 41 of the first active material layer 4 in the longitudinal direction of the current collector 1 and the edge of the fourth end 22 of the first insulating layer 2 in the longitudinal direction of the current collector 1 is greater than or equal to 0 mm. That is, the length of the gap between the first active material layer 4 and the first insulating layer 2 in the longitudinal direction of the current collector 1 is greater than or equal to 0 mm.

[0050] In a preferred embodiment, the length of the gap between the first active material layer 4 and the first insulating layer 2 in the length direction of the electrode is 2 mm; for example, a range consisting of any two of 0.5 mm, 1 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm or 5 mm.

[0051] In some embodiments, the distance between the edge of the eleventh end 71 of the second active material layer 7 in the longitudinal direction of the current collector 1 and the edge of the tenth end 52 of the second insulating layer 5 in the longitudinal direction of the current collector 1 is greater than or equal to 0 mm. That is, the length of the gap between the second active material layer 7 and the second insulating layer 5 in the longitudinal direction of the current collector 1 is greater than or equal to 0 mm.

[0052] In a preferred embodiment, the length of the gap between the second active material layer 7 and the second insulating layer 5 in the length direction of the pole piece is 2 mm; for example, a range consisting of any two of 0.5 mm, 1 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm or 5 mm.

[0053] As shown in FIG5 , in one embodiment, the present application provides a battery on the other hand, including an electrolyte, a separator 11 and the above-mentioned electrode sheets, wherein the electrode sheets include a positive electrode sheet 9 and / or a negative electrode sheet 10 .

[0054] Specifically, the positive electrode sheet 9 includes a positive electrode current collector 91, a positive electrode primer layer 93, a positive electrode insulating layer 92 and a positive electrode active material layer 94, wherein the positive electrode primer layer 93 includes a first positive electrode primer layer 931 and a second positive electrode primer layer 932, the positive electrode insulating layer 92 includes a first positive electrode insulating layer 921 and a second positive electrode insulating layer 922, and the positive electrode active material layer 94 includes a first positive electrode active material layer 941 and a second positive electrode active material layer 942.

[0055] The first positive electrode primer layer 931 and the first positive electrode insulating layer 921 are arranged side by side on one side of the positive electrode current collector 91, and the edge of the first positive electrode primer layer 931 and the edge of the first positive electrode insulating layer 921 are abutted. The area of ​​the first positive electrode insulating layer 921 at the abutting position is a first thinning area 923, and the thickness of the first thinning area 923 is less than the average thickness of the first positive electrode insulating layer 921 at the non-abutting position. The thickness of the first thinning area 923 of the first positive electrode insulating layer 921 is equal to the thickness of the first positive electrode primer layer 931; the first positive active material layer 941 is arranged on the surface of the first positive electrode primer layer 931 away from the positive electrode current collector 91, and the first positive active material layer 941 does not contact the first positive electrode insulating layer 921.

[0056] The second positive electrode primer layer 932 and the second positive electrode insulating layer 922 are arranged side by side on the other side of the positive electrode current collector 91, and the edge of the second positive electrode primer layer 932 and the edge of the second positive electrode insulating layer 922 are abutted, and the thickness of the second positive electrode insulating layer 922 in the abutting position is greater than the thickness of the second positive electrode primer layer 932; the second positive electrode active material layer 942 is arranged on the surface of the second positive electrode primer layer 932 away from the positive electrode current collector 91, and the second positive electrode active material layer 942 does not contact the second positive electrode insulating layer 922.

[0057] Specifically, the positive electrode current collector 91 may be aluminum foil or nickel foil. Furthermore, other positive electrode current collectors 91 commonly used in the art may be used.

[0058] Specifically, the positive electrode undercoat layer 93 includes: a first positive electrode active material, a first conductive agent, a first insulating inorganic filler and a first binder, wherein the first positive electrode active material includes one or more of lithium iron phosphate, lithium manganese iron phosphate, sodium iron phosphate, lithium vanadium phosphate, sodium vanadium phosphate, lithium vanadium oxyphosphate, sodium vanadium oxyphosphate, lithium vanadate, and lithium manganate; the first conductive agent includes one or more of carbon nanotubes, conductive carbon black, acetylene black, graphene, Ketjen black, and carbon fiber; the first insulating inorganic filler includes one or more of alumina ceramics, boehmite, magnesium oxide, and magnesium hydroxide; the first binder includes one or more of polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylic acid copolymer, polyacrylate, sodium carboxymethyl cellulose, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene, styrene-butadiene rubber, and the like.

[0059] Specifically, the positive electrode insulating layer 92 includes: a first insulating material and a second binder;

[0060] The first insulating material includes boehmite and magnesium oxide; boehmite has the advantages of high insulation and good thermal stability, and is used as an insulating layer coated on the current collector to prevent the occurrence of internal short circuits, but boehmite has a low expansion coefficient and low thermal conductivity. Magnesium oxide is also an insulating material, and has a high thermal expansion coefficient and high thermal conductivity. As the temperature rises, the expansion coefficient increases. When there is an aluminum foil short circuit, or the magnesium oxide coated around the aluminum foil expands due to heat, it can prevent further short circuits from occurring, thereby improving safety, such as needle puncture.

[0061] The second binder includes one or more of polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylic acid copolymer, polyacrylate, sodium carboxymethyl cellulose, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene, styrene-butadiene rubber, and the like.

[0062] The second binder allows for better adhesion between the insulating material and the positive electrode current collector 91, preventing the insulating material from falling off the surface of the positive electrode current collector 91, thereby preventing short circuits between the positive electrode sheets 9 when the battery is impacted or punctured by external forces, thereby improving the safety performance of the battery and electrical devices.

[0063] Specifically, the positive electrode active material layer 94 includes: a second positive electrode active material, a second conductive agent and a third binder;

[0064] In one embodiment, the second positive electrode active material includes one or more of lithium cobaltate, lithium vanadate, lithium manganate, lithium nickelate, lithium nickel cobalt manganate, lithium-rich manganese-based materials, lithium nickel cobalt aluminum oxide, and lithium titanate; the second conductive agent includes one or more of carbon nanotubes, conductive carbon black, acetylene black, graphene, Ketjen black, and carbon fiber; the third binder includes one or more of polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylic acid copolymer, polyacrylate, sodium carboxymethyl cellulose, polyvinyl pyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene, styrene-butadiene rubber, and the like; the third binder includes one or more of polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylic acid copolymer, polyacrylate, sodium carboxymethyl cellulose, polyvinyl pyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene, styrene-butadiene rubber, and the like.

[0065] Specifically, the negative electrode sheet 10 includes a negative electrode current collector 101 and a negative electrode active material layer 102 . The negative electrode active material layer 102 is coated on both sides of the negative electrode current collector 101 .

[0066] Specifically, the negative electrode current collector 101 is selected from a metal material that can conduct electrons. Preferably, the negative electrode current collector 101 includes metals such as stainless steel, Al, Ni, tin, copper, nickel, titanium, iron, or alloys thereof. In a more preferred embodiment, the negative electrode current collector 101 is selected from copper foil.

[0067] Specifically, the negative electrode active material layer 102 includes: a negative electrode active material, a conductive agent and a binder;

[0068] In one embodiment, the negative electrode active material includes one or more of natural graphite, artificial graphite, hard carbon, silicon material, and lithium metal material; the conductive agent includes one or more of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers; and the binder includes one or more of styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), water-based acrylic resin, polyacrylic acid (PAA), carboxymethyl cellulose (CMC), and carboxymethyl cellulose modified materials.

[0069] Specifically, the diaphragm 11 can be various diaphragm 11 materials suitable for lithium-ion batteries in the art, for example, it can be a combination of one or more including but not limited to single-layer PP (polypropylene), single-layer PE (polyethylene), polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester and natural fiber.

[0070] The battery of the present application further includes an electrolyte, which may be one or more of a gel electrolyte, a solid electrolyte, and an electrolyte solution, wherein the electrolyte solution includes a lithium salt and a non-aqueous solvent.

[0071] In some embodiments, the battery preparation method used is as follows: the above-mentioned positive electrode plate 9, separator 11, and negative electrode plate 10 are wound or stacked in sequence to form an electrode assembly, and then placed in, for example, an aluminum-plastic film, injected with electrolyte, formed, and packaged to make a lithium-ion battery.

[0072] Although some of the exemplary embodiments above are described using lithium-ion batteries as examples, those skilled in the art will appreciate after reading this application that, without departing from the spirit of this application, specific examples of batteries in this application can include all types of primary batteries or secondary batteries. In particular, the battery is a lithium secondary battery, including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery.

[0073] On the other hand, the present application provides an electrical device including the battery described above.

[0074] The electrical device of the embodiment of the present application is not particularly limited, and it can be any electrical device known in the prior art. In some embodiments, the electrical device may include, but is not limited to, an electronic cigarette, an electronic steam device, a wireless headset, a sweeping robot, an unmanned aerial vehicle, a laptop computer, a pen-input computer, a mobile computer, an e-book player, a portable phone, a portable fax machine, a portable copier, a portable printer, a head-mounted stereo headset, a video recorder, an LCD television, a portable cleaner, a portable CD player, a mini-disc, a transceiver, an electronic notepad, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, a car, a motorcycle, a power-assisted bicycle, a bicycle, a lighting fixture, a toy, a game console, a clock, a power tool, a flashlight, a camera, a large household battery and a lithium-ion capacitor, etc.

[0075] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A battery electrode sheet, wherein: Comprising: A current collector, a first bottom coating, a first insulating layer, a first active material layer, and a second active material layer; The first bottom coating and the first insulating layer are arranged side by side on one side of the current collector. The edge of the first bottom coating abuts against the edge of the first insulating layer. The area of the first insulating layer at the abutting position is a thinning area, and the thickness of the thinning area is less than the average thickness of the first insulating layer at the non-abutting position. The thickness of the thinning area of the first insulating layer is flush with the thickness of the first bottom coating. The first active material layer is disposed on the side of the first bottom coating away from the current collector, and the second active material layer is disposed on the other side of the current collector, and the projection of the second active material layer on the current collector covers the thinning area and the projection of the first bottom coating on the current collector.

2. The battery electrode according to claim 1, wherein: A second bottom coating and a second insulating layer are arranged side by side on the other side of the current collector. The edge of the second bottom coating abuts against the edge of the second insulating layer, and the thickness of the area of the second insulating layer at the abutting position is greater than the thickness of the second bottom coating.

3. The battery electrode according to any one of claims 1-2, wherein: The second active material layer is disposed on the surface of the second bottom coating away from the current collector, and the second active material layer does not contact the second insulating layer.

4. The battery electrode sheet according to claim 3, wherein: In the length direction of the current collector, the current collector includes a first end and a second end. The first insulating layer extends from the first end of the current collector to a position near the second end of the current collector, and the first bottom coating is located at the second end of the current collector; the second insulating layer is located at the first end of the current collector, and the second bottom coating extends from the second end of the current collector to a position near the first end of the current collector.

5. The battery electrode sheet according to claim 4, wherein: In the length direction of the current collector, the first insulating layer includes a third end and a fourth end, and the first bottom coating includes a fifth end and a sixth end. A thinning area is provided at the fourth end of the first insulating layer, and the thinning area abuts against the fifth end of the first bottom coating.

6. The battery electrode sheet according to claim 5, wherein: In the thickness direction of the electrode sheet, the thickness of the third end of the first insulating layer is Ta, and the thickness range of Ta is 3 - 15 μm; The thickness of the thinning area at the fourth end of the first insulating layer is Tb, and the thickness range of Tb is 2 - 10 μm. The thickness of the first bottom coating is Tc, and the thickness range of Tc is 2 - 10 μm; the thickness of the second insulating layer is Td, and the thickness range of Td is 3 - 15 μm, and the thickness of the second bottom coating is Te, and the thickness range of Te is 2 - 10 μm.

7. The battery electrode sheet according to claim 5, wherein: In the thickness direction of the electrode sheet, the thickness of the first active material layer is Tf, and the thickness range of Tf is 30 - 100 μm; the thickness of the second active material layer is Tg, and the thickness range of Tg is 30 - 100 μm.

8. The battery electrode sheet according to claim 6, wherein: In the length direction of the current collector, the first active material layer includes a seventh end and an eighth end. There is a gap between the seventh end of the first active material layer and the fourth end of the first insulating layer. The length of the gap is L1, and L1 satisfies: 0 mm ≤ L1 ≤ 5 mm; the second insulating layer includes a ninth end and a tenth end, the second active material layer includes an eleventh end and a twelfth end, and there is a gap between the tenth end of the second insulating layer and the eleventh end of the second active material layer. The length of the gap is L2, and L2 satisfies: 0 mm ≤ L2 ≤ 5 mm.

9. A battery, wherein: It includes an electrolyte, a separator, and the electrode sheet according to any one of claims 1-8, and the electrode sheet includes a positive electrode sheet and / or a negative electrode sheet.

10. An electrical device, wherein: It includes the battery according to claim 9.

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