阅读说明：本技术 一种锂离子电池及其制备方法和用途 (Lithium ion battery and preparation method and application thereof ) 是由 高灿 何巍 李倩伟 陈利权 宋帅帅 于 2020-07-10 设计创作，主要内容包括：本发明涉及一种锂离子电池及其制备方法和用途。所述锂离子电池包括依次设置的正极片、隔膜和负极片,在纵向满足：所述负极片的长度小于正极片的长度；所述正极片表面设置有正极材料涂层,以及位于所述正极材料涂层边缘的绝缘涂层,所述负极片边缘与所述绝缘涂层相对。所述锂离子电池采用正极片包覆负极片的设计工艺,将负极片边缘与所述绝缘涂层相对,即使在极端情况下,隔膜收缩,正极片和负极片接触,也能避免出现短路的风险,提高锂离子电池的安全性能。(The invention relates to a lithium ion battery and a preparation method and application thereof. The lithium ion battery comprises a positive plate, a diaphragm and a negative plate which are sequentially arranged, and the lithium ion battery satisfies the following conditions in the longitudinal direction: the length of the negative plate is smaller than that of the positive plate; the surface of the positive plate is provided with a positive material coating and an insulating coating positioned at the edge of the positive material coating, and the edge of the negative plate is opposite to the insulating coating. The lithium ion battery adopts a design process that the positive plate is coated with the negative plate, the edge of the negative plate is opposite to the insulating coating, and even if the diaphragm contracts and the positive plate and the negative plate are contacted under an extreme condition, the risk of short circuit can be avoided, and the safety performance of the lithium ion battery is improved.)

1. The utility model provides a lithium ion battery, its characterized in that, lithium ion battery is including positive plate, diaphragm and the negative pole piece that sets gradually, vertically satisfies: the length of the negative plate is less than that of the positive plate;

the surface of the positive plate is provided with a positive material coating and an insulating coating positioned at the edge of the positive material coating, and the edge of the negative plate is opposite to the insulating coating.

2. The lithium ion battery according to claim 1, wherein edges of both sides of the positive electrode tab in the longitudinal direction protrude with respect to the negative electrode tab;

preferably, the longitudinal edge of the negative electrode plate is opposite to the middle area of the insulating coating;

preferably, the distance between the longitudinal edge of the negative electrode plate and the longitudinal edge of the positive electrode plate is 0.3-5mm, preferably 0.5-4 mm.

3. The lithium ion battery of claim 1 or 2, wherein the insulating coating comprises an insulating material and a flame retardant material;

preferably, the insulating material comprises any one or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, acrylate rubber, styrene-butadiene rubber, acrylic resin, acrylic acid or acrylic amide, preferably acrylic acid;

preferably, the flame retardant material comprises any one or a combination of at least two of tetraphenyl (bisphenol-a) diphosphate, tetraphenylresorcinol diphosphate, aluminum diethylphosphinate, melamine polyphosphate, melamine, or benzoguanamine, preferably tetraphenyl (bisphenol-a) diphosphate;

preferably, the mass ratio of the flame-retardant material to the insulating material is (20-60): (40-80), preferably (30-50): (50-70);

preferably, the width of the insulating coating is 0.3-5mm, preferably 0.5-3 mm;

preferably, the thickness of one side of the insulating coating is 10-60 μm, preferably 15-50 μm;

preferably, the positive electrode material coating partially overlaps with the insulating coating;

preferably, the width of the partially overlapped region is 0.2-0.5 mm;

preferably, the positive plate further comprises a tab, and the width of the surface insulation coating of the tab is 0.2-4mm, preferably 0.5-2 mm.

4. A method for preparing a lithium ion battery according to any of claims 1-3, characterized in that the method comprises the steps of:

(1) coating the surface of the current collector with insulating slurry and anode slurry, wherein the coating area of the insulating slurry is positioned at the edge of the anode slurry coating area, so as to obtain an anode plate;

(2) and (2) sequentially arranging the positive plate, the diaphragm and the negative plate obtained in the step (1), wherein the length of the negative plate is smaller than that of the positive plate in the longitudinal direction, and the edge of the negative plate is opposite to the insulating coating, so that the lithium ion battery is prepared.

5. The method according to claim 4, wherein the insulating paste of step (1) comprises an insulating material and a flame retardant material;

preferably, the insulating material comprises any one or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, acrylate rubber, styrene-butadiene rubber, acrylic resin, acrylic acid or acrylic amide, preferably acrylic acid;

preferably, the flame retardant material comprises any one or a combination of at least two of tetraphenyl (bisphenol-a) diphosphate, tetraphenylresorcinol diphosphate, aluminum diethylphosphinate, melamine polyphosphate, melamine, or benzoguanamine, preferably tetraphenyl (bisphenol-a) diphosphate;

preferably, the mass ratio of the flame retardant material to the insulating material is (20-60): (40-80), preferably (30-50): (50-70).

6. The method according to claim 4 or 5, wherein the insulating slurry of the step (1) is coated along the length direction of the current collector;

preferably, the insulating paste of step (1) is coated to a width of 0.3-5mm, preferably 0.5-3 mm;

preferably, the thickness of the single side coated by the insulation paste in the step (1) is 10-60 μm, preferably 15-50 μm;

preferably, the positive electrode slurry of step (1) is partially overlapped with the region coated with the insulating slurry;

preferably, the width of the partially overlapping region is 0.2-0.5 mm.

7. The method according to any one of claims 4 to 6, wherein step (1) of coating the edges of the insulating paste coated area leaves a blank foil;

preferably, the positive plate in the step (1) is rolled, cut and die-cut;

preferably, the die cutting constructs a tab, and the tab comprises a hollow foil and a partial insulating coating;

preferably, the width of the partial insulating coating is 0.5-2 mm.

8. The method according to any one of claims 4 to 7, wherein the longitudinal edge of the negative electrode sheet of step (2) is opposite to the middle region of the insulating coating;

preferably, the distance between the longitudinal edge of the negative electrode plate and the longitudinal edge of the positive electrode plate in the step (2) is 0.3-5mm, preferably 0.5-4 mm.

9. Method according to any of claims 4-8, characterized in that the method comprises the steps of:

(1) coating insulating slurry and anode slurry on the surface of a current collector, wherein the thickness of a single coated surface of the insulating slurry is 15-50 microns, the width of the single coated surface of the insulating slurry is 0.5-3mm, a coating area of the insulating slurry is partially overlapped with a coating area of the anode slurry, the width of the partially overlapped area is 0.2-0.5mm, a hollow foil is reserved at the edge of the coating area of the insulating slurry, and the width of an insulating coating on the surface of a tab constructed by die cutting is 0.2-2mm, so that an anode plate is obtained;

the insulation slurry comprises an insulation material and a flame retardant material in a mass ratio of (30-50) - (50-70), wherein the insulation material comprises any one or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, acrylate, acrylic styrene-butadiene rubber, acrylate rubber, styrene-butadiene rubber, acrylic resin, acrylic acid or acrylic amide;

the flame retardant material comprises any one of tetraphenyl (bisphenol-A) diphosphate, tetraphenylresorcinol diphosphate, aluminum diethylphosphinate, melamine polyphosphate, melamine or benzoguanamine or a combination of at least two of the same;

(2) and (2) sequentially arranging the positive plate, the diaphragm and the negative plate obtained in the step (1), wherein the length of the negative plate is smaller than that of the positive plate in the longitudinal direction, the distance between the longitudinal edge of the positive plate and the longitudinal edge of the negative plate is 0.5-4mm, and the edge of the negative plate is opposite to the insulating coating on the surface of the positive plate, so that the lithium ion battery is prepared.

10. A new energy automobile, characterized in that the new energy automobile comprises the lithium ion battery according to any one of claims 1 to 3.

Technical Field

The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery and a preparation method and application thereof.

Background

The lithium ion battery is used as a power source of a new energy automobile, and with the increase of consumer demand, higher requirements are put on energy density and safety performance of the lithium ion battery, especially the safety performance of the lithium ion battery becomes a hot point of research, and the research on battery materials such as a diaphragm, electrolyte and active substances, a battery structure and the like is mainly carried out.

CN104701478A discloses a polyethylene microporous membrane containing an organic/inorganic composite cross-linked coating and a preparation method thereof. The invention uses aromatic heterocyclic polyester dihydric alcohol and aromatic isocyanate as basic components, combines a cross-linking agent, a foaming agent, a catalyst and inorganic nano-filler, and prepares coating liquid according to a certain composition proportion; coating the coating liquid on at least one surface of the polyethylene microporous membrane, and curing at a specific temperature to form an organic polymer/inorganic nano particle composite cross-linked coating with an open-cell foam structure on the surface of the polyethylene microporous membrane. The polyethylene microporous diaphragm keeps higher porosity and air permeability, simultaneously greatly improves the thermal shrinkage rupture temperature, and can obviously improve the use safety performance of the battery when being used as a diaphragm material of a power lithium ion battery.

CN110416613A discloses an electrolyte for improving cycle performance and safety performance of a lithium ion battery, which comprises lithium salt, a solvent, an electrolyte stabilizer and an additive; the solvent is a non-aqueous organic solvent, the non-aqueous organic solvent is at least one of carbonate, halogenated carbonate, carboxylate, propionate, fluoroether, aromatic hydrocarbon and halogenated aromatic hydrocarbon thereof, wherein halogen substitutes in the halogenated carbonate and the halogenated aromatic hydrocarbon are at least one of F, Cl, Br and I; the additive is at least one of dioxolane and derivatives thereof or dioxane and derivatives thereof. The electrolyte forms a protective film with extremely high stability on the surface of the cathode material, so that the cathode material is protected, and the purpose of improving the safety performance of the lithium ion battery is achieved.

CN105428722A discloses a high security performance lithium ion battery and battery package, including lithium ion battery monomer, lithium ion battery monomer includes battery housing, accepts in the inside electric core of taking utmost point ear of battery housing and locates the battery top cap of taking utmost point post on the battery housing, the inside electrolyte that has poured into of battery housing, the electricity is connected with electrically conducts between electric core utmost point ear and the battery top cap utmost point post and is connected fusing device. The conductive connection fusing device can automatically disconnect the charging and discharging circuit when the temperature of the battery rises to the warning temperature, so that the battery and the battery pack are prevented from being overcharged, short-circuited and overheated, and the safety performance of the battery and the battery pack is greatly improved.

In the traditional lithium ion battery preparation process, the negative plate exceeds the edge of the positive plate, namely the size of the negative plate is larger than that of the positive plate, and the positive plate falls in the negative plate. In extreme conditions, the diaphragm for isolating the positive electrode and the negative electrode shrinks, the positive electrode and the negative electrode are in contact, short circuit occurs, and great potential safety hazard exists. Although the above documents effectively improve the safety performance of the lithium ion battery from different angles, the above safety hazards cannot be eliminated from the source.

Based on the research of the prior art, how to eliminate the potential safety hazard of the short circuit of the positive plate and the negative plate caused by the contraction of the diaphragm under the extreme condition becomes the technical problem which needs to be solved urgently at present.

Disclosure of Invention

In view of the problems in the prior art, the invention provides a lithium ion battery and a preparation method and application thereof. The lithium ion battery adopts the design process of coating the cathode plate by the anode plate, the surface of the anode plate is provided with the insulating coating, the edge of the cathode plate is opposite to the insulating coating, and even if the diaphragm contracts under extreme conditions and the anode plate and the cathode plate are contacted, the risk of short circuit can be avoided, and the safety performance of the lithium ion battery is improved.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a lithium ion battery, in particular a laminated lithium ion battery, wherein the lithium ion battery comprises a positive plate, a diaphragm and a negative plate, which are sequentially arranged, and satisfy in a longitudinal direction: the length of the negative plate is smaller than that of the positive plate; the surface of the positive plate is provided with a positive material coating and an insulating coating positioned at the edge of the positive material coating, and the edge of the negative plate is opposite to the insulating coating.

In the invention, the length of the negative plate refers to the length of the negative material coating except the length of the negative lug; the length of the positive plate refers to the total length of the positive material coating and the insulating coating except the length of the positive lug.

In the invention, the term "opposite" means that the projection of the edge of the negative plate on the positive plate falls on the insulating coating on the positive plate.

In the lithium ion battery, in the longitudinal direction, the length of the negative plate is smaller than that of the positive plate, so that the positive plate is coated with the negative plate, the surface of the positive plate is provided with the insulating coating, the edge of the negative plate is opposite to the insulating coating, even if under extreme conditions, the diaphragm shrinks, the positive plate is in contact with the negative plate, the insulating coating plays an insulating role, the short circuit of the positive plate and the negative plate cannot be caused, the potential safety hazard is eliminated from the source, and the safety performance of the lithium ion battery is improved.

In the invention, the positive plate can be provided with the positive material coating and the insulating coating on one surface or on both surfaces, and can be selected according to actual requirements.

In the invention, the extending direction of the lug on the laminated lithium ion battery pole piece is taken as the longitudinal direction, and the direction vertical to the longitudinal direction is taken as the transverse direction. It should be noted that the longitudinal direction defined herein is only for convenience of description and understanding, and the longitudinal direction in practical use should be understood as the protruding direction of the laminated battery tab, and the longitudinal direction defined herein is not limited by the orientation in the use environment, and may be considered as the opposite longitudinal direction as long as the battery tab protrudes.

In the invention, the insulating coating is positioned at the edge of the anode material coating, namely the insulating coating is positioned on the surface of the anode plate and is connected with the anode material coating.

As a preferable technical solution of the present invention, the longitudinal edge of the negative electrode tab is opposite to the middle region of the insulating coating, and is not limited to the middle of the insulating coating. In the present invention, the intermediate region means not on the boundary of the insulating coating, i.e., the longitudinal edge of the negative electrode tab is not opposite to the boundary of the insulating coating, but is opposite to the space inside the boundary of the insulating coating.

Preferably, the distance between the longitudinal edge of the negative electrode sheet and the longitudinal edge of the positive electrode sheet is 0.3-5mm, that is, in the longitudinal direction, the two side edges of the positive electrode sheet respectively protrude 0.3-5mm relative to the edge of the negative electrode sheet, and may be, for example, 0.3mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, or 5 mm. The distance is too small, the process capability cannot be realized, and the distance is too large, which increases the cost and the weight of the battery, preferably 0.5-4 mm.

In the invention, the distance refers to the distance between the longitudinal edge of the negative plate and the longitudinal edge of the positive plate after the center positions of the negative plate and the positive plate are superposed.

Preferably, the insulating coating comprises an insulating material and a flame retardant material.

Preferably, the insulating material comprises any one of or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, acrylate rubber, styrene-butadiene rubber, acrylic resin, acrylic acid, or acrylic amide, wherein a typical but non-limiting combination: acrylic acid and acrylic ester, acrylic ester and acrylic amide, styrene-butadiene rubber and acrylic ester rubber, etc., and acrylic acid is preferable. The insulating material can play a role in insulation and bonding.

Preferably, the flame retardant material comprises any one or a combination of at least two of tetraphenyl (bisphenol-a) diphosphate, tetraphenylresorcinol diphosphate, aluminum diethylphosphinate, melamine polyphosphate, melamine, or benzoguanamine, preferably tetraphenyl (bisphenol-a) diphosphate.

Preferably, the mass ratio of the flame retardant material to the insulating material is (20-60): (40-80), and for example, may be 20:40, 20:50, 20:60, 20:80, 25:40, 25:50, 25:75, 30:40, 30:70, 30:80, 40:40, 40:00, 40:80, 50:50, 50:80, 60:40, 60:60, 60:70 or 60:80, and the like, and preferably is (30-50): and (50-70).

Preferably, the width of the insulating coating is 0.3-5mm, for example, it may be 0.3mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, or 5mm, etc., preferably 0.5-3 mm.

Preferably, the thickness of the insulating coating is 10-60 μm on one side, for example, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, etc., preferably 15-50 μm.

As a preferable technical solution of the present invention, the positive electrode material coating is partially overlapped with the insulating coating, and the partial overlapping can better prevent the short circuit of the positive electrode sheet and the negative electrode sheet.

Preferably, the width of the partially overlapping area is 0.2-0.5mm, and may be, for example, 0.2mm, 0.25mm, 0.3mm, 0.4mm, 0.45mm, 0.5mm, or the like.

Preferably, the positive plate further comprises a tab, and the width of the surface insulating coating of the tab is 0.2-4mm, and for example, the width can be 0.2mm, 0.3mm, 0.5mm, 1mm, 1.2mm, 1.8mm, 2mm, 2.4mm, 2.7mm, 3mm, 3.2mm, 3.5mm, 3.8mm or 4mm, and the like, and is preferably 0.5-2 mm.

In a second aspect, the present invention provides a method for preparing a lithium ion battery as described in the first aspect, the method comprising the steps of:

(1) coating the surface of the current collector with insulating slurry and anode slurry, wherein the coating area of the insulating slurry is positioned at the edge of the anode slurry coating area, so as to obtain an anode plate;

(2) and (2) sequentially arranging the positive plate, the diaphragm and the negative plate obtained in the step (1), wherein the length of the negative plate is smaller than that of the positive plate in the longitudinal direction, and the edge of the negative plate is opposite to the insulating coating, so that the lithium ion battery is prepared.

According to the invention, the insulating slurry is coated on the edge of the positive slurry coating area, the insulating coating is formed on the surface of the current collector, the length of the negative plate is smaller than that of the positive plate, the positive plate is coated on the negative plate, so that the edge of the negative plate is opposite to the insulating coating, and the problem of short circuit of the positive plate and the negative plate caused by diaphragm shrinkage in the traditional lithium ion battery preparation process is solved from the source. The method does not affect other preparation processes of the traditional lithium ion battery except for coating the cathode plate with the anode plate, is easy to replace the preparation process of the traditional lithium ion battery, has high safety and has higher application value.

In the invention, the types of the anode slurry, the insulating slurry and the current collector are not particularly limited, and the anode slurry can be an anode slurry containing lithium iron phosphate or an anode slurry containing lithium cobaltate; the insulating slurry can be an insulating slurry containing aluminum oxide or an insulating slurry containing titanium dioxide; the current collector may be an aluminum foil, any kind commonly used by those skilled in the art, and is suitable for use in the present invention.

In the present invention, the coating sequence of the positive electrode paste and the insulating paste is not particularly limited, and may be simultaneous coating or stepwise coating, and any coating sequence commonly used by those skilled in the art is applicable to the present invention, and preferably simultaneous coating. The synchronous coating can shorten the production period and improve the production efficiency.

In the present invention, the negative electrode sheet is not particularly limited, and any negative electrode sheet commonly used by those skilled in the art may be used in the present invention.

Illustratively, the negative electrode sheet may be prepared by:

and coating the negative electrode slurry on the surface of a current collector to obtain the negative electrode plate.

Preferably, the insulating paste of step (1) comprises an insulating material and a flame retardant material.

Preferably, the insulating material comprises any one or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, acrylate rubber, styrene-butadiene rubber, acrylic resin, acrylic acid or acrylic amide, preferably acrylic acid.

Preferably, the flame retardant material comprises any one or a combination of at least two of tetraphenyl (bisphenol-a) diphosphate, tetraphenylresorcinol diphosphate, aluminum diethylphosphinate, melamine polyphosphate, melamine, or benzoguanamine, preferably tetraphenyl (bisphenol-a) diphosphate.

Preferably, the mass ratio of the flame retardant material to the insulating material is (20-60): (40-80), and for example, may be 20:40, 20:50, 20:60, 20:80, 25:40, 25:50, 25:75, 30:40, 30:70, 30:80, 40:40, 40:00, 40:80, 50:50, 50:80, 60:40, 60:60, 60:70 or 60:80, and the like, and preferably is (30-50): and (50-70).

Preferably, the insulating slurry of step (1) is coated along the length direction of the current collector.

Preferably, the width of the insulating paste coating in step (1) is 0.3-5mm, such as 0.3mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, or 5mm, and preferably 0.5-3 mm.

Preferably, the thickness of the single side coated with the insulating paste in the step (1) is 10-60 μm, for example, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm or 60 μm, etc., preferably 15-50 μm.

Preferably, the positive electrode paste of step (1) partially overlaps with the insulating paste-coated region.

Preferably, the width of the partially overlapping area is 0.2-0.5mm, and may be, for example, 0.2mm, 0.25mm, 0.3mm, 0.4mm, 0.5mm, or the like.

Preferably, the margin of the insulating paste coating area coated in the step (1) is reserved with a hollow foil.

Preferably, the positive plate in the step (1) is rolled, cut and die-cut.

In the present invention, the operations and conditions for rolling, slitting and die cutting are not particularly limited, and any operations and conditions commonly used by those skilled in the art may be applied to the present invention.

Preferably, the die cutting constructs a tab comprising a hollow foil and a partially insulating coating.

Preferably, the width of the partially insulating coating is 0.5-2mm, and may be, for example, 0.5mm, 1mm, 1.2mm, 1.8mm, 2mm, or the like.

As a preferable technical scheme of the invention, the longitudinal edge of the negative plate in the step (2) is opposite to the middle area of the insulating coating.

Preferably, the distance between the longitudinal edge of the negative electrode plate and the longitudinal edge of the positive electrode plate in the step (2) is 0.3-5mm, for example, 0.3mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, or 5mm, etc., preferably 0.5-4 mm.

As a further preferred embodiment of the present invention, the method comprises the steps of:

(1) coating insulating slurry and anode slurry on the surface of a current collector, wherein the thickness of a single coated surface of the insulating slurry is 15-50 microns, the width of the single coated surface of the insulating slurry is 0.5-3mm, a coating area of the insulating slurry is partially overlapped with a coating area of the anode slurry, the width of the partially overlapped area is 0.2-0.5mm, a hollow foil is reserved at the edge of the coating area of the insulating slurry, and the width of an insulating coating on the surface of a tab constructed by die cutting is 0.2-2mm, so that an anode plate is obtained;

the insulation slurry comprises an insulation material and a flame retardant material in a mass ratio of (30-50) - (50-70), wherein the insulation material comprises any one or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, acrylate, acrylic styrene-butadiene rubber, acrylate rubber, styrene-butadiene rubber, acrylic resin, acrylic acid or acrylic amide;

the flame retardant material comprises any one of tetraphenyl (bisphenol-A) diphosphate, tetraphenylresorcinol diphosphate, aluminum diethylphosphinate, melamine polyphosphate, melamine or benzoguanamine or a combination of at least two of the same;

(2) and (2) sequentially arranging the positive plate, the diaphragm and the negative plate obtained in the step (1), wherein the length of the negative plate is smaller than that of the positive plate in the longitudinal direction, the distance between the longitudinal edge of the positive plate and the longitudinal edge of the negative plate is 0.5-4mm, and the edge of the negative plate is opposite to the insulating coating on the surface of the positive plate, so that the lithium ion battery is prepared.

In a third aspect, the invention provides a new energy automobile, which includes the lithium ion battery according to the first aspect.

Compared with the prior art, the invention has at least the following beneficial effects:

(1) according to the lithium ion battery, the structure that the positive plate wraps the negative plate is adopted, and meanwhile, the edge of the negative plate is opposite to the insulating coating on the surface of the positive plate, so that the problem of short circuit of the positive plate and the negative plate caused by diaphragm shrinkage under extreme conditions is solved from the source, and the safety performance of the lithium ion battery is improved; in the short circuit test result, the lithium ion battery has no short circuit phenomenon; in the safety performance test, the phenomena of explosion, fire and liquid leakage do not occur, and the reject ratio is 0 percent;

(2) the safety performance of the lithium ion battery is further improved by regulating and controlling the single-side thickness of the insulating coating, the width of the overlapping area of the insulating coating and the anode material coating and the width of the insulating coating on the surface of the lug;

(3) the preparation method provided by the invention is easy to replace the traditional preparation process of the lithium ion battery, and has high safety.

Drawings

Fig. 1 is a flowchart of the positive electrode sheet production method provided in example 1.

Fig. 2 is a schematic structural view of a positive electrode sheet prepared by the coating process provided in example 1.

Fig. 3 is a schematic structural diagram of a negative electrode sheet prepared by the coating process provided in example 1.

Fig. 4 is a schematic structural view of a positive electrode sheet of the laminated lithium-ion battery provided in example 1.

Fig. 5 is a schematic structural view of a negative electrode sheet of the laminated lithium-ion battery provided in example 1.

Fig. 6 is a schematic diagram of the coating structure of the positive plate and the negative plate of the laminated lithium ion battery provided in example 1.

Fig. 7 is a partially enlarged view of the edges of the positive-electrode sheet and the negative-electrode sheet provided in example 1.

The method comprises the following steps of 1-positive pole current collector, 2-positive pole material coating, 3-insulating coating, 4-positive pole lug, 5-negative pole current collector, 6-negative pole material coating and 7-negative pole lug.

Detailed Description

The technical solution of the present invention will be further described with reference to the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.