CN115719793A - Positive plate and preparation method thereof - Google Patents
Positive plate and preparation method thereof Download PDFInfo
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- CN115719793A CN115719793A CN202211376115.1A CN202211376115A CN115719793A CN 115719793 A CN115719793 A CN 115719793A CN 202211376115 A CN202211376115 A CN 202211376115A CN 115719793 A CN115719793 A CN 115719793A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
The invention belongs to the technical field of batteries, and relates to a positive plate which comprises a positive current collector, a safety coating, a positive active material layer and an insulating coating, wherein the positive current collector is provided with a first surface and a second surface which are opposite, the second surface is provided with a first covering area and a second covering area which are connected, the safety coating covers the first surface and the first covering area, the insulating coating covers the second covering area, the positive active material layer covers the safety coating, the safety coating positioned in the first covering area is provided with a first end and a second end which are opposite, the first end is covered with the positive active material layer, the second end is covered with the insulating coating, a part of the insulating coating covering the second end, which extends out of the positive active material layer, is covered with the positive active material layer, or the positive active material layer and a part of the insulating coating are overlapped in a staggered mode, and the problems that the end of the active material layer is thinned and the battery is deformed due to the fact that the positive lithium is separated out are effectively solved. In addition, the invention also discloses a preparation method of the positive plate.
Description
Technical Field
The invention belongs to the technical field of batteries, and particularly relates to a positive plate and a preparation method thereof.
Background
The lithium ion battery has the advantages of high energy density, high output power, light weight, small volume, long cycle life, high working voltage, high power density, good safety, environmental protection and the like, and has wide application prospect in the aspects of portable electric appliances, digital products, electric tools, large-scale energy storage, electric traffic power supplies, electric automobiles and the like. However, in the process of disassembling the consumer electronic product, the lithium ion battery is easy to catch fire and explode when being subjected to abnormal conditions such as collision, extrusion or puncture, thereby causing serious consequences.
The safety of the battery is related to the coating condition of the pole pieces, when the positive pole piece of the battery has the condition of poor coating, the thinning condition can occur in the coating of the positive pole piece, so that the lithium precipitation can occur to the positive pole piece corresponding to the thinning position of the corresponding lithium ion battery in the circulating process, and further the phenomenon of battery cell deformation is caused. Therefore, a new technical solution is needed to solve the above problems.
Disclosure of Invention
One of the objects of the present invention is: the positive plate can effectively solve the problem that the end part of an active material layer is thinned, and the situation that lithium is separated from the position of the pole piece corresponding to the end part of the battery in the circulating process and the battery is deformed is avoided.
In order to achieve the purpose, the invention adopts the following technical scheme:
a positive electrode sheet, comprising:
a positive current collector having opposing first and second faces, the second face having first and second footprint areas connected;
a security coating covering the first face and the first footprint;
a positive active material layer covering the safety coating;
an insulating coating covering the second coverage area;
the safety coating layer positioned in the first coverage area is provided with a first end and a second end which are opposite, and the first end is covered with the positive electrode active material layer;
the second end is covered with the insulating coating and the part of the insulating coating extending out of the second end covers one end of the positive active material layer or
The second end covers there is anodal active material layer just anodal active material layer with a part dislocation overlap joint of insulating coating.
Further, the positive active material layer has with the end section that insulating coating is connected, the end section with parallel and level about the second end, insulating coating has the first extension section that covers the end section, at this moment its end is cut thin when the positive active material layer coats and is not influenced, the positive active material layer can not coat heavily, and then can not appear making the problem that lithium is educed to the corresponding positive pole.
Further, the positive pole active material layer have with the end section that insulating coating connects, the end section covers the second end, insulating coating has the first extension section that covers the end section, first extension section with the second end is parallel and level from top to bottom or form the overlap region from top to bottom, and at this moment its end is cut thin unaffected when the positive pole active material layer coats, the positive pole active material layer can not coat heavily, and then can not appear making the problem that the lithium is educed to the corresponding positive pole appearance.
Further, the security coating on the first face has third and fourth opposing ends, the third end being proximate to the first end, the first end being spaced from the second end by a distance less than the third end and the fourth end, such that the security coating on the first face has a length greater than the security coating on the second face.
Further, the insulating coating has a fifth end, the fifth end is located on one side of the second coverage area far away from the first coverage area, the positive active material layer has a seventh end which is level with the fourth end up and down, and the fifth end and the fourth end are level with each other up and down or form dislocation up and down. By such an arrangement, in the tape running direction of the pole piece, the side of the insulating coating layer far away from the first covering area may or may not exceed the seventh end of the positive electrode active material layer.
Further, the thickness of the safety coating layer on the first surface and the first covering area is 0.001 mm-0.015 mm, the safety coating layer comprises a safety substance, a conductive agent, an adhesive and a solvent, and the mass ratio of the safety substance, the conductive agent, the adhesive and the solvent is (60-95): 0.1-3): 1-10): 80-100.
Further, the safety substance includes, but is not limited to, at least one of lithium nickel manganese cobaltate, lithium manganese iron phosphate, sodium iron phosphate, lithium vanadium phosphate, sodium vanadium phosphate, lithium vanadyl phosphate, sodium vanadyl phosphate, lithium vanadate, lithium manganate, lithium nickelate, lithium nickel cobalt manganese, lithium rich manganese based material, lithium nickel cobalt aluminate or lithium titanate, or ceramic.
Further, the conductive agent includes, but is not limited to, at least one of carbon nanotubes, conductive carbon black, acetylene black, graphene, ketjen black, or carbon fibers, and the solvent may be deionized water.
Further, the binder includes, but is not limited to, at least one of polyvinylidene fluoride, copolymers of vinylidene fluoride-hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, sodium carboxymethylcellulose, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene, or styrene butadiene rubber.
Further, the positive electrode active material layer comprises a positive electrode active material, a conductive agent, a binder and a solvent, and the mass ratio of the positive electrode active material, the conductive agent, the binder and the solvent is (70-99): 0.1-3): 0.2-10): 50-100.
Further, the positive active material includes, but is not limited to, at least one of lithium cobaltate, lithium nickel manganese cobaltate, lithium manganese iron phosphate, sodium iron phosphate, lithium vanadium phosphate, sodium vanadium phosphate, lithium vanadyl phosphate, sodium vanadyl phosphate, lithium vanadate, lithium manganate, lithium nickelate, lithium nickel cobalt manganate, lithium rich manganese based material, lithium nickel cobalt aluminate, or lithium titanate.
Further, the thickness of the insulating coating is 0.001 mm-0.015 mm, the insulating coating comprises an insulating substance, a binder, a thickener and a solvent, and the mass ratio of the insulating substance, the binder, the thickener and the solvent is (60-80): 10-26): 1-5): 80-100. The battery cell performance is not influenced by the coating weight of the insulating coating, the lithium precipitation phenomenon of the corresponding anode is not caused, and the deformation of the battery cell is not caused.
Further, the insulating substance includes, but is not limited to, at least one of boehmite, alumina; the thickener includes, but is not limited to, at least one of carboxymethyl cellulose, carboxyethyl cellulose, guar gum, polyethylene oxide, terpineol, polyvinyl alcohol, polyacrylic acid, polyurethane.
The invention also aims to provide a preparation method of the positive plate, which comprises the following steps:
coating a safety coating on the first surface and the first coverage area of the positive current collector, and coating a positive active material layer on the surface of the safety coating to enable the positive active material layer to cover the first end of the safety coating;
coating an insulating coating on the second coverage area of the positive electrode current collector;
the insulating coating covers the second end of the safety coating and the protruding part of the insulating coating covers one end of the positive active material layer or
And enabling the positive active material layer to cover the second end of the safety coating and enabling the positive active material layer and a part of the insulating coating to be in staggered lap joint.
The invention has the beneficial effects that: the positive plate comprises a positive current collector, a safety coating, a positive active material layer and an insulating coating, wherein the positive current collector is provided with a first surface and a second surface which are opposite, the second surface is provided with a first covering area and a second covering area which are connected, the safety coating covers the first surface and the first covering area, the safety coating can effectively improve the safety of the plate, the insulating coating covers the second covering area, the positive active material layer covers the safety coating, the safety coating positioned in the first covering area is provided with a first end and a second end which are opposite, the first end of the safety coating is covered with the positive active material layer, the second end of the safety coating is covered with the insulating coating, a part of the insulating coating covering the second end covers one end of the positive active material layer or the second end of the safety coating is covered with the positive active material layer, the positive active material layer and one part of the insulating coating are overlapped in a staggered manner, the insulating coating and the positive active material layer are overlapped, so that the end part of the positive active material layer and the insulating coating are overlapped in a staggered manner, the lithium segregation situation of the battery can be effectively solved in the coating production process, and the safety performance of the battery can be obviously improved.
Drawings
Features, advantages and technical effects of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.
Fig. 1 is a schematic structural diagram of a first embodiment of the present invention.
Fig. 2 is a schematic structural diagram of a second embodiment of the present invention.
Fig. 3 is a schematic structural diagram of a third embodiment of the present invention.
Fig. 4 is a schematic structural view of a fourth embodiment of the present invention.
Fig. 5 is a schematic structural diagram of a fifth embodiment of the present invention.
Fig. 6 is a schematic structural view of a sixth embodiment of the present invention.
Wherein the reference numerals are as follows:
11. a positive current collector; 12. a security coating; 13. a positive electrode active material layer; 14. an insulating coating; 12a, a first end; 12b, a second end; 12c, a third end; 12d, a fourth end; 13a, a first section; 13b, a tail section; 13c, a sixth end; 13d, a seventh end; 14a, a first extension section; 14b, fifth end.
Detailed Description
As used in the specification and in the claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. The description and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. The term "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the desired technical effect. In this application, the terms "first," "second," and the like are used solely to distinguish between different components and are not to be construed as indicating or implying relative importance.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "lapped," "fixed," and the like are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In order to make the technical solutions and advantages of the present invention clearer, the present invention and its advantageous effects are described in further detail below with reference to fig. 1 to 6 and the specific embodiments, but the embodiments of the present invention are not limited thereto.
Implementation mode one
A positive plate comprises a positive current collector 11, a safety coating 12, a positive active material layer 13 and an insulating coating 14, wherein the positive current collector 11 is provided with a first surface and a second surface which are opposite, the second surface of the positive current collector 11 is provided with a first coverage area and a second coverage area which are connected, the safety coating 12 covers the first surface and the first coverage area of the positive current collector 11, the insulating coating 14 covers the second coverage area of the positive current collector 11, and the positive active material layer 13 covers the safety coating 12, so that the safety coating 12 and the positive active material layer 13 are arranged on two surfaces of the positive current collector 11, and the safety coating 12 is superposed between the positive current collector 11 and the positive active material layer 13 in the moving direction of a pole piece to form a sandwich structure.
In the pole piece moving direction, the safety coating 12 located in the first covering area of the second surface has a first end 12a and a second end 12b which are opposite, the first end 12a of the safety coating 12 is covered with the positive active material layer 13, the second end 12b of the safety coating 12 is covered with the insulating coating 14, and a part of the insulating coating 14 covering the second end 12b extends out to cover one end of the positive active material layer 13.
Specifically, in the pole piece running direction, the positive electrode active material layer 13 has a tail section 13b connected to the insulating coating 14, the tail section 13b of the positive electrode active material layer 13 is flush with the second end 12b of the safety coating 12, and the insulating coating 14 has a first extension section 14a covering the tail section 13b of the positive electrode active material layer 13. Cover to anodal active material layer 13's tail section 13b through insulating coating 14's first extension section 14a for insulating coating 14's first extension section 14a is close to anodal active material layer 13's tail section 13b and both exist the overlapping, the size that will overlap sets up to 1mm ~ 10mm, and anodal active material layer 13's tail section 13b and safety coating 12's second end 12b are parallel and level from top to bottom, it is not influenced that anodal active material layer 13 its end to end is cut thin when the coating this moment, anodal active material layer 13 can not coat heavily, and then the problem that the lithium is appeared to the messenger corresponding positive pole appears, the security that obviously improves the battery.
Specifically, the safety coating slurry is coated on the first surface of the positive current collector 11 through extrusion equipment or gravure roller equipment, continuous coating is performed, the first surface has no reserved current collector or aluminum foil, and the thickness of the safety coating 12 is 0.001-0.015 mm; and then coating the gap of the safety coating 12 on a first covering area on the second surface of the positive current collector 11, wherein the safety coating 12 on the second surface is provided with a first end 12a and a second end 12b in the traveling direction of the pole piece, and the thickness of the safety coating 12 is 0.001 mm-0.015 mm. Then, by using an extrusion device or a gravure roll device, the positive active material slurry is firstly coated on the safety coating 12 in the first surface of the positive current collector 11, and then the positive active material slurry is coated on the safety coating 12 in the second surface of the positive current collector 11, wherein in the pole piece moving direction, the positive active material layer 13 in the second surface of the positive current collector 11 has a first section 13a and a tail section 13b, and at this time, 13b is flush with 12 b. Then, the insulating coating paste is coated on a second coverage area different from the first coverage area in a second surface (lower surface) of the positive current collector 11 by an extrusion apparatus or a gravure roll apparatus; the insulating coating 14 has a first extension 14a and a fifth end 14b in the direction of the running of the pole piece, and the length of the insulating coating 12 is 10-300 mm. The thickness of the insulating coating 14 is 0.001 mm-0.015 mm. The first extension segment 14a of the insulating coating is close to the tail segment 13b of the positive electrode active material layer 13, and the two segments are overlapped with the overlapping size of 1-10 mm.
Preferably, in the positive electrode sheet, the thicknesses of the first surface of the positive electrode current collector 11 and the safety coating 12 of the first covering area are both 0.001mm to 0.015mm, and more preferably, the thicknesses may be 0.005mm to 0.008mm, 0.008mm to 0.012mm; the thickness of the insulating coating 14 in the second covering area of the positive electrode current collector 11 is 0.001mm to 0.015mm, and the more preferable thickness is 0.005mm to 0.008mm, 0.008mm to 0.012mm; if the thickness of the safety coating 12 or the insulating coating 14 is too small, foil leakage is easy to occur, the positive current collector 11 cannot be protected to the maximum extent, and meanwhile, the internal resistance of the coating is small, so that the safety performance of the lithium ion battery cannot be effectively improved; if the thickness of the safety coating 12 or the insulating coating 14 is too large, although the safety performance of the lithium ion battery can be improved, the safety performance of the lithium ion battery is greatly deteriorated, so that the service life of a consumer product is influenced, in addition, the thickness of a positive plate is greatly increased, the energy density of the lithium ion battery is reduced, and the market competitiveness is reduced.
Preferably, the safety coating layer 12 includes a safety substance, a conductive agent, a binder and a solvent, and the mass ratio of the safety substance, the conductive agent, the binder and the solvent is (60-95): 0.1-3): 1-10): 80-100.
Preferably, the positive electrode active material layer 13 includes a positive electrode active material, a conductive agent, a binder, and a solvent, and the mass ratio of the positive electrode active material, the conductive agent, the binder, and the solvent is (70-99): 0.1-3): 0.2-10): 50-100.
Preferably, the insulating coating 14 includes an insulating substance, a binder, a thickener, and a solvent, and the mass ratio of the insulating substance, the binder, the thickener, and the solvent is (60-80): 10-26): 1-5): 80-100.
The safety material comprises at least one of nickel manganese lithium cobaltate, lithium manganese iron phosphate, sodium iron phosphate, lithium vanadium phosphate, sodium vanadium phosphate, lithium vanadyl phosphate, sodium vanadyl phosphate, lithium vanadate, lithium manganate, lithium nickelate, lithium nickel cobalt manganese manganate, a lithium-rich manganese-based material, lithium nickel cobalt aluminate or lithium titanate or ceramics; the positive active material includes but is not limited to at least one of lithium cobaltate, lithium nickel manganese cobaltate, lithium manganese iron phosphate, sodium iron phosphate, lithium vanadium phosphate, sodium vanadium phosphate, lithium vanadium oxide phosphate, sodium vanadium oxide phosphate, lithium vanadate, lithium manganate, lithium nickelate, lithium nickel cobalt manganese, lithium-rich manganese-based material, lithium nickel cobalt aluminate or lithium titanate; the conductive agent includes, but is not limited to, at least one of carbon nanotubes, conductive carbon black, acetylene black, graphene, ketjen black, or carbon fibers; binders include, but are not limited to, at least one of polyvinylidene fluoride, copolymers of vinylidene fluoride-hexafluoropropylene, polyamides, polyacrylonitrile, polyacrylates, polyacrylic acids, polyacrylates, sodium carboxymethylcellulose, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene, or styrene butadiene rubber; the solvent may be deionized water; the insulating substance includes but is not limited to at least one of boehmite and alumina; the thickener includes, but is not limited to, at least one of carboxymethyl cellulose, carboxyethyl cellulose, guar gum, polyethylene oxide, terpineol, polyvinyl alcohol, polyacrylic acid, polyurethane.
In the present embodiment, the safety coating 12 can effectively prevent the direct contact short circuit between the positive electrode current collector and the negative electrode active material from causing the battery to fail; meanwhile, as the temperature rises in the short-circuit process, the internal resistance of the safety coating 12 is obviously increased, and the thermal runaway of the battery cell can be effectively inhibited. In addition, the embodiment avoids the inconsistency of the thickness of the position with the surrounding area caused by the overlapping of the safety coating 12 and the insulating coating 14, avoids the problem that the thinning of the position cannot meet the specification when the active substances are coated, and overcomes the technical defect that the battery cell is deformed due to the occurrence of lithium precipitation on the pole piece corresponding to the position in the circulation process of the lithium ion battery. In the application, the battery cell performance is not affected by the coating weight of the insulating coating 14, the lithium precipitation phenomenon of the corresponding anode is not caused, and the deformation of the battery cell is further avoided. The insulating coating 14 can protect the positive current collector 11 to the maximum extent, so that the existence of an empty aluminum foil on the second surface of the positive current collector 11 is avoided, the short circuit of an aluminum anode, empty copper and empty aluminum is also avoided, and the safety performance of the lithium ion battery is improved.
Second embodiment
Unlike the first embodiment, referring to fig. 2, the second end 12b of the safety coating 12 of the present embodiment is not directly connected to the insulating coating 14, but the second end 12b of the safety coating 12 is covered with the positive electrode active material layer 13, and the positive electrode active material layer 13 overlaps with a part of the insulating coating 14 in a staggered manner.
Specifically, the positive electrode active material layer 13 has a tail section 13b connected to the insulating coating 14, the tail section 13b covers the second end 12b, the insulating coating 14 has a first extension section 14a covering the tail section 13b, and the first extension section 14a is flush with the second end 12 b. Wherein, the first extension section 14a of insulating coating 14 is close to the end section 13b of anodal active material layer 13 and both have 1mm ~ 10 mm's overlap portion, and, because the size that the end section 13b of anodal active material layer 13 surpasss the second end 12b of safety coating 12 is 1mm ~ 10mm, anodal active material layer 13 is thin when the coating its head and the tail is cut and is not influenced this moment, anodal active material layer 13 can not coat heavily, and then it can not appear making the problem that lithium analysis appears in the corresponding positive pole, can show the security that improves the battery.
Other structures of this embodiment are the same as those of the first embodiment, and are not described herein again.
Third embodiment
Unlike the first embodiment, referring to fig. 3, the second end 12b of the safety coating 12 of the present embodiment is not directly connected to the insulating coating 14, but the second end 12b of the safety coating 12 is covered with the positive electrode active material layer 13, and the positive electrode active material layer 13 overlaps with a part of the insulating coating 14 in a staggered manner.
Specifically, the positive electrode active material layer 13 has a tail section 13b connected to the insulating coating 14, the tail section 13b covers the second end 12b, the insulating coating 14 has a first extension section 14a covering the tail section 13b, and the first extension section 14a and the second end 12b form an overlapping region in the upper and lower directions, and the size of the overlapping region may be 1mm to 10mm. Wherein, the first extension section 14a of insulating coating 14 is close to anodal active material layer 13's tail section 13b and both have 1mm ~ 10 mm's overlap portion, and, because anodal active material layer 13's tail section 13b surpasss the size of the second end 12b of safety coating 12 and is 1mm ~ 10mm, anodal active material layer 13 is cut thin by its head and the tail when the coating and is not influenced this moment, anodal active material layer 13 can not coat heavily, and then it can not appear making the problem that lithium analysis appears in the corresponding positive pole, can show the security that improves the battery.
Other structures of this embodiment are the same as those of the first embodiment, and are not described again here.
Example IV
Unlike the first embodiment, referring to fig. 4, the insulating coating 14 of the present embodiment has a fifth end 14b in the pole piece moving direction, the fifth end 14b is located on the side of the second covering area far from the first covering area, and the length of the insulating coating 14 may be 50mm to 300mm.
The safety coating 12 on the first surface of the positive electrode collector 11 has a third end 12c and a fourth end 12d opposite to each other, the third end 12c is close to the first end 12a, the distance between the first end 12a and the second end 12b is smaller than the distance between the third end 12c and the fourth end 12d, and the fifth end 14b and the fourth end 12d are flush with each other or are offset from each other.
The positive electrode active material layer 13 has a sixth end 13c flush with the third end 12c, the positive electrode active material layer 13 has a seventh end 13d flush with the fourth end 12d, and the fifth end 14b of the insulating coat 14 may or may not extend beyond the seventh end 13d of the positive electrode active material layer 13.
Other structures of this embodiment are the same as those of the first embodiment, and are not described herein again.
Fifth embodiment
Unlike the second embodiment, referring to fig. 5, the insulating coating 14 of the present embodiment has a fifth end 14b in the pole piece moving direction, the fifth end 14b is located on the side of the second covering area far from the first covering area, and the length of the insulating coating 14 may be 50mm to 300mm.
The safety coating 12 on the first surface of the positive electrode current collector 11 has a third end 12c and a fourth end 12d opposite to each other, the third end 12c is close to the first end 12a, the distance between the first end 12a and the second end 12b is smaller than the distance between the third end 12c and the fourth end 12d, and the fifth end 14b and the fourth end 12d are flush with each other or are staggered from top to bottom.
The positive electrode active material layer 13 has a sixth end 13c flush with the third end 12c, the positive electrode active material layer 13 has a seventh end 13d flush with the fourth end 12d, and the fifth end 14b of the insulating coat 14 may or may not extend beyond the seventh end 13d of the positive electrode active material layer 13.
Other structures of this embodiment are the same as those of the second embodiment, and are not described again here.
Sixth embodiment
In contrast to the third embodiment, referring to fig. 6, the insulating coating 14 of the present embodiment has a fifth end 14b in the direction of the running of the pole piece, the fifth end 14b is located on the side of the second covering area far from the first covering area, and the length of the insulating coating 14 may be 50mm to 300mm.
The safety coating 12 on the first surface of the positive electrode collector 11 has a third end 12c and a fourth end 12d opposite to each other, the third end 12c is close to the first end 12a, the distance between the first end 12a and the second end 12b is smaller than the distance between the third end 12c and the fourth end 12d, and the fifth end 14b and the fourth end 12d are flush with each other or are offset from each other.
The positive electrode active material layer 13 has a sixth end 13c flush with the third end 12c, the positive electrode active material layer 13 has a seventh end 13d flush with the fourth end 12d, and the fifth end 14b of the insulating coat 14 may or may not extend beyond the seventh end 13d of the positive electrode active material layer 13.
Other structures of this embodiment are the same as those of the third embodiment, and are not described again here.
Seventh embodiment mode
A preparation method of a positive plate comprises the following steps:
coating a safety coating 12 on the first surface and the first coverage area of the positive electrode current collector 11, and coating a positive electrode active material layer 13 on the surface of the safety coating 12, so that the positive electrode active material layer 13 covers the first end 12a of the safety coating 12;
coating an insulating coating 14 on a second coverage area of the positive electrode current collector 11;
the insulating coating 14 is made to cover the second end 12b of the safety coating 12 and the protruding part of the insulating coating 14 covers one end of the positive electrode active material layer 13 or
The positive electrode active material layer 13 is made to cover the second end 12b of the safety coat 12 and the positive electrode active material layer 13 is offset lapped with a part of the insulating coat 14.
Variations and modifications to the above-described embodiments may also occur to those skilled in the art, which fall within the scope of the invention as disclosed and taught herein. Therefore, the present invention is not limited to the above-mentioned embodiments, and any obvious improvement, replacement or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Claims (10)
1. A positive electrode sheet, comprising:
a positive current collector (11), the positive current collector (11) having opposing first and second faces, the second face having first and second footprint areas connected;
a security coating (12) covering the first face and the first footprint;
a positive electrode active material layer (13) covering the safety coating layer (12);
an insulating coating (14) covering the second footprint;
the safety coating (12) located in the first footprint area has opposite first (12 a) and second (12 b) ends, the first end (12 a) being covered with the positive active material layer (13);
the second end (12 b) is covered with the insulating coating (14) and a part of the insulating coating (14) covering the second end (12 b) extends out of one end of the anode active material layer (13) or
The second end (12 b) is covered with the positive electrode active material layer (13) and the positive electrode active material layer (13) is in staggered lap joint with a part of the insulating coating (14).
2. The positive electrode sheet according to claim 1, wherein: the positive electrode active material layer (13) has a tail section (13 b) connected to the insulating coating (14), the tail section (13 b) is flush with the second end (12 b) above and below, and the insulating coating (14) has a first extension section (14 a) covering the tail section (13 b).
3. The positive electrode sheet according to claim 1, wherein: the positive electrode active material layer (13) has a tail section (13 b) connected to the insulating coating (14), the tail section (13 b) covers the second end (12 b), the insulating coating (14) has a first extension section (14 a) covering the tail section (13 b), and the first extension section (14 a) and the second end (12 b) are flush with each other.
4. The positive electrode sheet according to claim 1, wherein: the positive electrode active material layer (13) is provided with a tail section (13 b) connected with the insulating coating (14), the tail section (13 b) covers the second end (12 b), the insulating coating (14) is provided with a first extending section (14 a) covering the tail section (13 b), and the first extending section (14 a) and the second end (12 b) form an overlapping region up and down.
5. The positive electrode sheet according to any one of claims 1 to 4, wherein: the security coating (12) on the first face has opposed third (12 c) and fourth (12 d) ends, the third end (12 c) being adjacent the first end (12 a), the first end (12 a) being spaced from the second end (12 b) by a distance less than the distance between the third (12 c) and fourth (12 d) ends.
6. The positive electrode sheet according to claim 5, wherein: the insulating coating (14) is provided with a fifth end (14 b), the fifth end (14 b) is positioned on one side of the second coverage area far away from the first coverage area, and the fifth end (14 b) and the fourth end (12 d) are level up and down or form dislocation up and down.
7. The positive electrode sheet according to claim 5, wherein: the thickness of the safety coating (12) on the first surface and the first coverage area is 0.001-0.015 mm, the safety coating (12) comprises a safety substance, a conductive agent, an adhesive and a solvent, and the mass ratio of the safety substance, the conductive agent, the adhesive and the solvent is (60-95): 0.1-3): 1-10): 80-100.
8. The positive electrode sheet according to any one of claims 1 to 4, wherein: the positive electrode active material layer (13) contains a positive electrode active material, a conductive agent, a binder and a solvent, and the mass ratio of the positive electrode active material, the conductive agent, the binder and the solvent is (70-99): 0.1-3): 0.2-10): 50-100.
9. The positive electrode sheet according to any one of claims 1 to 4, wherein: the thickness of the insulating coating (14) is 0.001 mm-0.015 mm, the insulating coating (14) comprises an insulating substance, an adhesive, a thickening agent and a solvent, and the mass ratio of the insulating substance to the adhesive to the thickening agent to the solvent is (60-80): 10-26): 1-5): 80-100.
10. A method for producing a positive electrode sheet according to any one of claims 1 to 9, comprising the steps of:
coating a safety coating (12) on a first surface and a first coverage area of a positive electrode current collector (11), coating a positive electrode active material layer (13) on the surface of the safety coating (12), and enabling the positive electrode active material layer (13) to cover a first end (12 a) of the safety coating (12);
coating an insulating coating (14) on the second coverage area of the positive electrode current collector (11);
the insulating coating (14) covers the second end (12 b) of the safety coating (12) and a part of the insulating coating (14) extends to cover one end of the positive electrode active material layer (13) or
The positive electrode active material layer (13) covers the second end (12 b) of the safety coating (12), and the positive electrode active material layer (13) and a part of the insulating coating (14) are in staggered lap joint.
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| CN202211376115.1A CN115719793A (en) | 2022-11-04 | 2022-11-04 | Positive plate and preparation method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024022218A1 (en) * | 2022-07-26 | 2024-02-01 | 惠州锂威新能源科技有限公司 | Positive electrode sheet structure and lithium ion battery |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024022218A1 (en) * | 2022-07-26 | 2024-02-01 | 惠州锂威新能源科技有限公司 | Positive electrode sheet structure and lithium ion battery |
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