CN216084939U

CN216084939U - Pole piece strip material, pole piece monomer and battery

Info

Publication number: CN216084939U
Application number: CN202122085370.8U
Authority: CN
Inventors: 朱庆权
Original assignee: Evergrande New Energy Technology Shenzhen Co Ltd
Current assignee: Evergrande New Energy Technology Shenzhen Co Ltd
Priority date: 2021-08-31
Filing date: 2021-08-31
Publication date: 2022-03-18
Anticipated expiration: 2031-08-31

Abstract

The utility model provides a pole piece belt material, a pole piece monomer and a battery, wherein the pole piece belt material comprises: the foil is provided with a pole piece area, a pole lug area and a cutting area, and any two of the pole piece area, the pole lug area and the cutting area are adjacent; an active material layer coated on the electrode piece region; and the first auxiliary coating is coated on the cutting area and used for assisting a cutter to cut the cutting area so as to form a pole piece and a pole lug. According to the pole piece strip, the pole piece monomer and the battery, the first auxiliary coating is coated in the cutting area by adopting the first auxiliary coating, and when the cutting area is cut, the first auxiliary coating can assist a cutter to cut a foil, so that the cutting part of the cutting area is protected, burrs are prevented from being generated at the cutting part, the burrs are prevented from piercing a diaphragm, micro short circuit is avoided, and the safety and the service life of the battery are guaranteed.

Description

Pole piece strip material, pole piece monomer and battery

Technical Field

The utility model belongs to the technical field of batteries, and particularly relates to a pole piece strip, a pole piece monomer and a battery.

Background

Lithium ion batteries are very critical in electric vehicle systems, and the safety of lithium ion batteries is related to the safety of automobiles. The high Potential (high voltage test) short-circuit rate of the existing lithium ion battery test is high, and meanwhile, the battery placement process has the disadvantages of serious self-discharge, obvious voltage drop and high reject ratio.

The abnormal lithium ion battery is disassembled and analyzed, and the fact that the material height of the positive pole piece close to the positive pole ear side is large is found, burrs are prone to occurring on the positive pole piece, a diaphragm is pierced, and micro short circuit is caused. Meanwhile, the edge position of the positive pole piece is polarized greatly, the resistance value is increased, and the internal resistance of the lithium ion battery is influenced.

The positive pole piece is at the in-process of cross cutting, and the material height of the positive pole piece is difficult to control, simultaneously because positive pole piece thickness is big, the cross cutting in-process, the burr appears easily in the positive pole piece, causes the internal resistance increase of lithium ion battery.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model aims to provide a pole piece belt material to solve the technical problem that burrs are easy to appear on a positive pole piece in the die cutting process of the positive pole piece in the prior art.

In order to achieve the purpose, the utility model adopts the technical scheme that: providing a pole piece tape stock comprising:

the foil is provided with a pole piece area, a pole lug area and a cutting area, and any two of the pole piece area, the pole lug area and the cutting area are adjacent;

an active material layer coated on the electrode sheet region; and the number of the first and second groups,

the first auxiliary coating is coated on the cutting area and used for assisting the cutter to cut the cutting area so as to form a pole piece and a pole lug.

Through adopting first auxiliary coating, establish first auxiliary coating scribble in the cutting area, when cutting the cutting area, first auxiliary coating can assist the cutter to cut the foil, protects cutting area cutting part, prevents that cutting part from producing the burr, avoids the burr to pierce through the diaphragm, causes little short circuit to the safety and the life of guarantee battery.

In one embodiment, the first auxiliary coating is a graphene coating or a silica coating; or the first auxiliary coating comprises a graphene coating coated on the cutting area and a silicon dioxide coating coated on the outer side of the graphene layer.

Through adopting above-mentioned technical scheme, can assist the cutter cutting foil, and avoid producing the burr.

In one embodiment, the thickness of the first auxiliary coating layer is 3 μm to 40 μm; and/or the width of the first auxiliary coating is 0.5mm-4 mm.

By adopting the technical scheme, the cost can be saved, and the energy density of the battery can be guaranteed.

In one embodiment, the number of the pole piece areas is two, the two columns of pole piece areas are arranged along the width direction of the foil, the number of the pole lug areas is two, the two columns of pole lug areas are respectively located on the outer sides of the two columns of pole piece areas, the number of the cutting areas is two, and the two columns of cutting areas are respectively located on the outer sides of the two columns of pole piece areas.

By adopting the technical scheme, the production efficiency of the pole piece monomer can be improved.

In one embodiment, the number of the pole piece regions is multiple rows, and the multiple rows of the pole piece regions are arranged along the length direction of the foil; the number of the polar lug areas is multiple, and the multiple rows of polar lug areas are distributed along the length direction of the foil; the cutting areas are arranged in a plurality of rows, and the cutting areas and the lug areas are alternately distributed outside the lug areas along the length direction of the foil.

By adopting the technical scheme, a plurality of pole piece monomers can be obtained after slitting.

In one embodiment, the foil is further provided with a cutting area between two adjacent pole piece areas, and the cutting area is coated with a second auxiliary coating.

Through adopting above-mentioned technical scheme, the burr that produces when can reduce the district's of cutting.

In one embodiment, the second auxiliary coating is a graphene coating or a silica coating; or the second auxiliary coating comprises a graphene coating coated on the cutting area and a silicon dioxide coating coated on the outer side of the graphene layer.

In one embodiment, the two sides of the pole piece region are respectively coated with an active material layer; and/or two surfaces of the cutting area are respectively coated with a first auxiliary coating.

Through adopting above-mentioned technical scheme, can reduce the thickness of foil single face active substance layer, the cutting in the cutting region of being convenient for.

In one embodiment, the active material layer is a positive electrode active material layer, and the foil is an aluminum foil; alternatively, the active material layer is a positive electrode active material layer or a negative electrode active material layer, and the foil is a copper foil.

By adopting the technical scheme, the positive pole piece and the negative pole piece can be formed.

The embodiment of the utility model also provides a pole piece monomer which is formed by cutting the pole piece strip material in any one of the embodiments.

Through adopting above-mentioned technical scheme, can reduce the burr on the pole piece monomer, be favorable to improving the security of battery.

The embodiment of the utility model also provides a battery, which comprises the pole piece monomer in the embodiment.

Through adopting above-mentioned technical scheme, can improve the security of battery.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a schematic view of a pole piece tape according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view taken along A-A of FIG. 1;

FIG. 3 is a schematic view of a pole piece strip according to another embodiment of the present invention;

fig. 4 is a schematic structural diagram of a pole piece monomer obtained by cutting the pole piece tape material in fig. 1.

Wherein, in the figures, the respective reference numerals:

100-pole piece monomer;

10-a foil; 11-pole piece region; 111-pole piece; 12-a cutting zone; 13-polar ear region; 131-a tab; 14-a slitting zone;

20-an active material layer;

30-a first auxiliary coating;

40-second auxiliary coating.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention 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 merely illustrative of the utility model and are not intended to limit the utility model.

It is to be understood that the terms "length," "width," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the present invention and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must be in a particular orientation, constructed and operative in a particular orientation, and are not to be construed as limiting the present invention.

In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

Referring to fig. 1, fig. 2 and fig. 4 together, a description will now be given of a pole piece tape according to an embodiment of the present invention. The pole piece strip comprises a foil 10, an active substance layer 20 and a first auxiliary coating 30. The foil 10 is provided with a pole piece area 11, a pole lug area 13 and a cutting area 12, any two of the pole piece area 11, the pole lug area 13 and the cutting area 12 are adjacent, an active substance layer 20 is coated on the pole piece area 11, the pole piece area 11 is used for cutting to form a pole piece 111, the cutting area 12 is used for cutting by a cutter so as to remove redundant parts of the pole lug area 13 to form a pole lug 131, a first auxiliary coating 30 is coated on the cutting area 12, the first auxiliary coating 30 is used for assisting the cutter to cut the foil 10 in the cutting area 12, and when the cutter cuts the cutting area, the pole piece strip is cut to form the pole piece 111 and the pole lug 131.

In this embodiment, when the tab area 13 of the pole piece tape is cut into the tab 131, the excess portion of the tab area 13 can be cut along the cutting area 12, so that the tab 131 is formed in the tab area 13. Through adopting first auxiliary coating 30, establish first auxiliary coating 30 scribble at cutting area 12, when cutting area 12 cuts, first auxiliary coating 30 can assist the cutter to cut foil 10, protects cutting area 12 cutting part, prevents that cutting part from producing the burr, avoids the burr to pierce through the diaphragm, causes little short circuit to the safety and the life of guarantee battery.

In an embodiment of the present invention, referring to fig. 1, fig. 2 and fig. 4, the first auxiliary coating 30 is a graphene coating. By adopting the graphene coating, the internal resistance of the pole piece monomer 100 can be reduced, the voltage drop of the battery can be reduced, and the heat dissipation of the connection part of the pole piece 111 and the pole lug 131 can be facilitated. Because graphite alkene has better lubrication action, when cutting the pole piece area material, graphite alkene can improve the cutting effect for the cutting plane is more level and smooth, reduces the burr that produces, and keeps cutting edge's straightness, improves the security performance of battery. Moreover, the graphene coating can cover the two sides of the cutting surface, so that the membrane can be prevented from being cut by the edge of the cutting surface, and the short circuit risk of self-discharge abnormity and Hi-pot test is reduced.

In another embodiment of the present invention, referring to fig. 1 to 3, the first auxiliary coating 30 is a silicon dioxide coating. The silicon dioxide coating is uniformly coated on the cutting area 12, burrs can be effectively prevented from being generated in the die cutting process, meanwhile, the silicon dioxide coating is coated between the tab area 13 and the pole piece area 11, the situation that the diaphragm is pierced at the position where the tab 131 is connected with the pole piece 111 can be prevented, the adjacent positive pole piece and the negative pole piece are short-circuited, and the safety of the battery is improved. Moreover, the silicon dioxide coating can cover the two sides of the cutting surface, so that the membrane can be prevented from being cut by the edge of the cutting surface, and the self-discharge abnormity and the short circuit risk of the Hi-pot test are reduced. Further, the silicon dioxide in the silicon dioxide coating can react with HF, so that the gas production risk of the battery can be reduced.

In a further embodiment of the utility model, the first auxiliary coating 30 comprises a graphene coating and a silica coating, the graphene coating being applied on the foil 10 and the silica coating being applied on the graphene coating. Therefore, the internal resistance of the pole piece monomer 100 can be reduced, the heat dissipation of the connection part of the pole piece 111 and the pole lug 131 is promoted, and the diaphragm can be prevented from being pierced at the connection position of the pole lug 131 and the pole piece 111, so that the adjacent positive pole piece and the negative pole piece are short-circuited, and the safety of the battery is improved.

In one embodiment of the present invention, referring to fig. 1 to 3, the thickness of the first auxiliary coating 30 is 3 μm to 40 μm. So on the one hand be convenient for reduce the quantity of coating in first auxiliary coating 30, reduce the cost of first auxiliary coating 30, on the other hand first auxiliary coating 30 thickness is less, is favorable to the coating technique worker of first auxiliary coating 30, and can avoid first auxiliary coating 30 thickness too big, prevents that first auxiliary coating 30 from falling the material during the cutting, reduces the dust that the cutting produced. Alternatively, the thickness of the first auxiliary coating 30 is 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, or 35 μm, and the like, and the type and thickness of the first auxiliary coating 30 may be selected according to the performance of the first auxiliary coating 30 and the performance of the foil 10, so as to reduce burrs generated when the foil 10 is cut.

In one embodiment of the present invention, referring to fig. 1 to 3, the width of the first auxiliary coating 30 ranges from 0.5mm to 4 mm. When adopting the cutting die to cut cutting district 12 like this, can provide sufficient width for the cutting of cutting district 12, moreover, the width of controlling first auxiliary coating 30 can reduce the width that cutting district 12 took pole piece 111, ensures battery energy density. Alternatively, the width of the first auxiliary coating layer 30 may be 1mm, 2mm, 3mm, or the like, and the width of the first auxiliary coating layer 30 may be adjusted according to the accuracy of the cutting position of the cutting die, so as to secure the energy density of the battery, and control the cutting position to be covered with the first auxiliary coating layer 30. Wherein the width direction of the first auxiliary coating layer 30 is perpendicular to the length direction of the first auxiliary coating layer 30 and the thickness direction of the first auxiliary coating layer 30, and the cutting line of the cutting region 12 (the dotted line along the length direction of the cutting region 12 in fig. 1) may be located at the middle of the cutting region 12 in the width direction or a position biased toward the polar ear region 13.

In an embodiment of the present invention, referring to fig. 1 to 3, the first auxiliary coating 30 is in a strip shape, and the cutting region 12 is in a strip shape, so that the widths of the active material layer 20 and the first auxiliary coating 30 can be conveniently controlled, the coating of the first auxiliary coating 30 and the active material layer 20 is convenient, and the processing of the pole piece strip is convenient.

In an embodiment of the present invention, referring to fig. 1 to 3, the number of the pole piece areas 11 is two, two columns of the pole piece areas 11 are arranged in parallel, two columns of the pole lug areas 13 are two, two columns of the cutting areas 12 are two, the two columns of the cutting areas 12 are respectively located at the outer sides of the two columns of the pole piece areas 11, the two columns of the pole lug areas 13 are respectively located at the outer sides of the two columns of the pole piece areas 11, one side of each cutting area 12 is adjacent to the adjacent pole lug area 13, and the other side of each cutting area 12 is adjacent to the adjacent pole piece area 11. Therefore, the pole piece belt material can be cut off from the middle of the two rows of pole piece areas 11, and the pole piece belt material is cut into two rows of pole piece monomers 100, so that the production efficiency of the pole piece monomers 100 is improved. Of course, in other embodiments of the present invention, the number of the pole piece regions 11 may be one or more columns, such as three columns, four columns, five columns, etc., and the number of the cutting regions 12 and the number of the tab regions 13 are equal to the number of the pole piece regions 11.

In an embodiment of the present invention, referring to fig. 1 to 3, the number of the cutting regions 12 is multiple, and the multiple rows of the cutting regions 12 are disposed along the length direction of the foil 10; the number of the cutting areas 12 is multiple rows, and the multiple rows of the cutting areas 12 are distributed along the length direction of the foil 10; the number of the polar lug regions 13 is multiple, and the multiple rows of polar lug regions 13 are distributed along the length direction of the foil 10; the cut out regions 12 and the tab regions 13 are arranged alternately outside the pole piece regions 11 along the length of the foil 10. Therefore, the pole piece belt material can be cut by the middle of two adjacent rows of pole piece areas 11, and the pole piece belt material is cut into a plurality of pole piece monomers 100, so that the production efficiency of the pole piece monomers 100 is improved. Of course, in this embodiment, a plurality of columns of pole piece regions 11, a plurality of columns of cutting regions 12, and a plurality of columns of pole lug regions 13 may be disposed on the foil 10, so that the pole piece regions 11 on the foil 10 are in a rectangular array, so that a plurality of pole piece monomers 100 can be obtained after cutting. Wherein the length direction of the foil 10 is the same as the length direction of the cutting area 12.

In an embodiment of the present invention, referring to fig. 1 to 3, a dividing region 14 is further disposed on the foil 10, the dividing region 14 is located between two adjacent pole piece regions 11, the dividing region 14 is used for being cut by a cutter to cut the two adjacent pole piece regions 11, the dividing region 14 is coated with a second auxiliary coating 40, the dividing region 14 is connected with the cutting region 12, and the second auxiliary coating 40 is connected with the first auxiliary coating 30. Can fix a position the position of cutting through cutting district 14 like this, scribble at cutting district 14 and establish second auxiliary coating 40, can be when cutting two continuous pole piece districts 11, protection foil 10 cutting position prevents that the cutting position from producing the burr, avoids the burr to pierce through the diaphragm, causes little short circuit to the safety and the life of guarantee battery. Furthermore, the slitting area 14 and the cutting area 12 are enclosed into a rectangular frame shape, so that when the pole piece strip is cut into the pole piece units 100, the cutting of the pole piece 111 is protected, burrs are prevented from being generated on the edge of the pole piece 111, and the safety performance of the battery is improved.

In an embodiment of the present invention, referring to fig. 1 to 3, the second auxiliary coating 40 is a graphene coating. By adopting the graphene coating, the internal resistance of the pole piece monomer 100 can be reduced, and the voltage drop of the battery can be reduced. When the pole piece strip is cut, the graphene can improve the cutting effect, so that the cutting surface is smoother, burrs generated are reduced, the flatness of the cutting edge is kept, and the safety performance of the battery is improved. Moreover, the graphene coating can cover the two sides of the cutting surface, so that the membrane can be prevented from being cut by the edge of the cutting surface, and the short circuit risk of self-discharge abnormity and Hi-pot test is reduced.

In another embodiment of the present invention, referring to fig. 1 to 3, the second auxiliary coating 40 is a silicon dioxide coating. The silicon dioxide coating is uniformly coated on the slitting area 14, so that burrs can be effectively prevented from being generated in the slitting process, the diaphragm is prevented from being pierced, the adjacent positive pole piece and the adjacent negative pole piece are prevented from being short-circuited, and the safety of the battery is improved. Moreover, the silicon dioxide coating can cover the two sides of the cutting surface, so that the membrane can be prevented from being cut by the edge of the cutting surface, and the self-discharge abnormity and the short circuit risk of the Hi-pot test are reduced. Further, the silicon dioxide in the silicon dioxide coating can react with HF, so that the gas production risk of the battery can be reduced.

In a further embodiment of the utility model, the second auxiliary coating 40 comprises a graphene coating and a silica coating, the graphene coating being applied on the foil 10 and the silica coating being applied on the graphene coating. Therefore, the internal resistance of the pole piece monomer 100 can be reduced, burrs can be prevented from being reduced, the diaphragm is prevented from being pierced, the adjacent positive pole piece and the adjacent negative pole piece are prevented from being short-circuited, and the safety of the battery is improved.

Alternatively, the second auxiliary coating 40 and the first auxiliary coating 30 may be made of the same material, and the thickness of the second auxiliary coating 40 and the thickness of the first auxiliary coating 30 may be the same, so as to facilitate the processing of the second auxiliary coating 40 and the first auxiliary coating 30.

In one embodiment of the present invention, referring to fig. 1 to 3, active material layers 20 are coated on both sides of the plate region 11. This is advantageous in increasing the thickness of the active material layer 20 on the electrode sheet region 11, and in improving the stability of the active material layer 20 on the foil 10. Moreover, the performances of the two sides of the pole piece region 11 can be consistent, which is beneficial to improving the performance of the battery. Of course, in other embodiments, the pole piece region 11 may be coated with the active material layer 20 on one side to form a pole piece tape.

In one embodiment of the utility model, both sides of the cutting zone 12 are coated with a first auxiliary coating 30. Thus, when the cutter cuts from both sides of the cutting region 12, the first auxiliary coating 30 can protect the cutting portion and reduce the generation of burrs. Also, after the cutting is completed, the first auxiliary coating layer 30 covers both sides of the cutting region 12, and the edge of the cutting region 12 can be prevented from cutting the diaphragm. In this embodiment, both sides of the slitting section 14 can be coated with a second auxiliary coating 40 to prevent burrs from being generated during cutting. Of course, in other embodiments, the cutting area 12 may be coated with the first auxiliary coating 30 on one side, and the cutting area 14 may be coated with the second auxiliary coating 40 on one side to assist cutting and reduce burrs generated at the cutting portion.

In a first embodiment of the present invention, referring to fig. 1, fig. 2 and fig. 4, the active material layer 20 is a positive active material layer, and the foil 10 is a positive foil. The positive electrode active material layer is coated on the positive electrode foil, so that a positive electrode sheet strip can be formed. Because the thickness of positive pole piece area material is thicker, first auxiliary coating 30 can prevent that the cutting of anodal foil from producing the burr, and in addition, cutting district 12 does not have anodal active material layer, and anodal active material layer falls the material when can avoiding cutting, is favorable to improving the free security performance of positive pole piece. Optionally, the anode foil is an aluminum foil, and the aluminum foil is cheap, light and convenient to process.

In this embodiment, the manufacturing process of the positive electrode sheet monomer includes:

s11, preparing auxiliary layer slurry, wherein the auxiliary layer slurry is used for coating to form a first auxiliary coating 30;

s12, preparing positive electrode slurry, wherein the positive electrode slurry is used for coating and forming a positive electrode active material layer;

and S13, coating the positive electrode slurry on a pole piece area 11 of the aluminum foil, rolling the coated aluminum foil in a protective layer slurry cutting area 12 of the aluminum foil, and cutting after rolling to obtain a positive electrode piece monomer.

Optionally, the positive electrode slurry includes lithium nickel cobalt manganese oxide, a carbon nanotube, a conductive agent SP (super pl, conductive carbon black), a binder PVDF (poly (vinylidene fluoride), polyvinylidene fluoride) polymer, a degasifier, and a solvent NMP, wherein the mass ratio of the lithium nickel cobalt manganese oxide is 96% -97.5%, the mass ratio of the carbon nanotube is 0.5% -0.7%, the mass ratio of the conductive agent SP is 0.9% -1.1%, the mass ratio of the binder is 1% -1.5%, and the mass ratio of the degasifier is 0.2% -1.5%. Thus, the positive active material layer and the aluminum foil can form a positive pole piece.

In a second embodiment of the present invention, referring to fig. 1 to 3, the active material layer 20 is a negative active material layer, and the foil 10 is a negative foil. By coating the negative electrode foil with the negative electrode active material layer, a negative electrode tab strip can be formed. When the cutting, first auxiliary coating 30 can prevent that the cutting of negative pole foil from producing the burr, and moreover, cutting area 12 does not have negative pole active material layer, and cutting area 12 falls the material when can avoiding the cutting, is favorable to improving the free security performance of negative pole piece. Optionally, the negative foil is a copper foil, the chemical property of the copper foil is stable, the processing is convenient, the thickness of the negative foil is lower than that of the positive foil, and the aluminum foil can be used as the positive foil, so that the cost of the battery is reduced, and the quality of the battery is reduced.

In this embodiment, the manufacturing process of the negative electrode sheet monomer includes:

s21, preparing auxiliary layer slurry, wherein the auxiliary layer slurry is used for coating to form a first auxiliary coating 30;

s22, preparing negative electrode slurry, wherein the negative electrode slurry is used for coating and forming a negative electrode active material layer;

and S23, coating the negative pole slurry on the pole piece area 11 of the copper foil, rolling the coated copper foil in the protective layer slurry in the cutting area 12 of the copper foil, and cutting after rolling to obtain the negative pole piece monomer.

Optionally, the negative electrode active material layer is formed by coating a negative electrode slurry, and the negative electrode slurry includes graphite, a binder CMC (sodium carboxymethyl cellulose), deionized water, a conductive agent SP, and a SBR (Styrene-butadiene rubber) emulsion, wherein a mass ratio of the graphite is 95% to 98%, a mass ratio of the binder CMC is 1% to 2%, a mass ratio of the conductive agent SP is 0.4% to 0.6%, and a mass ratio of the SBR emulsion is 1.5% to 1.9%. Thus, the negative electrode active material layer and the copper foil can form a negative electrode sheet.

In one embodiment of the utility model, the graphene coating is formed by coating graphene slurry, and the graphene slurry comprises graphene powder (mass ratio is 85% -89%), a binder (mass ratio is 11% -15%), and a solvent. When the graphene slurry is prepared, a solvent is added according to the solid content of 20% -45% of the graphene slurry, materials are mixed according to the revolution speed of 25 rpm/rotation speed of 3000rpm, the materials are uniformly stirred in a stirring pot after being mixed, the graphene slurry is obtained, and the viscosity of the graphene slurry is controlled to be 3000 +/-1000 cp, so that the graphene slurry can be coated conveniently.

In another embodiment of the utility model, the silicon dioxide coating is formed by coating silicon dioxide slurry, and the silicon dioxide slurry comprises silicon dioxide powder (85-89% by mass), a binder (11-15% by mass) and a solvent. When the silicon dioxide slurry is prepared, a solvent is added according to the solid content of 37-55% of the silicon dioxide slurry, the materials are mixed according to the revolution speed of 25 rpm/the rotation speed of 3000rpm, the silicon dioxide slurry is obtained by uniformly stirring in a stirring pot after mixing, and the viscosity of the silicon dioxide slurry is controlled at 3000cp so as to facilitate the coating of the silicon dioxide slurry.

Optionally, the binder comprises: at least one of polyvinylidene fluoride, copolymer of polyhexafluoropropylene-polyvinylidene fluoride, polyvinyl acetate, polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, alkylated polyethylene oxide, polyvinyl ether, polymethyl methacrylate, polyethylacrylate, polytetrafluoroethylene, polyvinyl chloride, polyacrylonitrile, polyvinyl pyridine, styrene-butadiene rubber, acrylonitrile-butadiene rubber. The binder may be a PVDF (poly (vinylidene fluoride), polyvinylidene fluoride) binder.

Alternatively, the solvent comprises: at least one of N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, N-dimethylaminopropylamine, ethylene oxide and tetrahydrofuran, and the solvent may be NMP (N-methylpyrrolidinone).

The embodiment of the present invention further provides a pole piece unit 100, please refer to fig. 1, fig. 2, and fig. 4, wherein the pole piece unit 100 is formed by cutting the pole piece tape material in any one of the embodiments. The pole piece monomer 100 is obtained by cutting the pole piece belt material in the embodiment, burrs at the cutting edge of the pole piece monomer 100 can be reduced, the falling material of the active material layer 20 can be reduced, the safety of the pole piece monomer 100 is improved, and the safety and the service life of the battery are guaranteed.

The embodiment of the utility model also provides a battery, and the battery comprises the pole piece monomer 100 in any embodiment. Optionally, the battery comprises a bare cell and an aluminum-plastic film, the stacked body comprises a positive pole piece monomer, a diaphragm and a positive pole piece monomer, the negative pole piece monomer, the diaphragm and the positive pole piece monomer are stacked to obtain the bare cell, and the bare cell is packaged in the aluminum-plastic film. The positive pole piece monomer in the battery is the pole piece monomer 100 in the above embodiment, and the negative pole piece monomer, the diaphragm and the positive pole piece monomer can be laminated through a Z-shaped lamination. The pole piece monomer 100 is obtained by cutting the pole piece strip material in the embodiment, so that burrs on the edge of the positive pole piece monomer in the battery are reduced, the safety performance of the battery is improved, and the service life of the battery is prolonged. Of course, in this embodiment, the single negative electrode tab may also be the single electrode tab 100 structure in the above embodiments.

According to the table data, after the positive pole piece monomer adopts the graphene coating or the silicon dioxide coating, the Hi-pot fraction defective and the short circuit fraction defective can be reduced, and the positive pole piece monomer adopts the graphene coating and can reduce the internal resistance of the battery.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. Pole piece area material, its characterized in that includes:

an active material layer coated on the electrode piece region; and the number of the first and second groups,

the first auxiliary coating is coated on the cutting area and used for assisting a cutter to cut the cutting area so as to form a pole piece and a pole lug.

2. The pole piece tape stock of claim 1, wherein: the first auxiliary coating is a graphene coating or a silicon dioxide coating; or the first auxiliary coating comprises a graphene coating coated on the cutting area and a silicon dioxide coating coated on the outer side of the graphene layer.

3. The pole piece tape stock of claim 2, wherein: the thickness of the first auxiliary coating is 3-40 μm; and/or the width of the first auxiliary coating is 0.5mm-4 mm.

4. The pole piece tape stock of claim 1, wherein: the number of the pole piece areas is two, the pole piece areas are arranged along the width direction of the foil, the number of the pole lug areas is two, the pole lug areas are located on the two outer sides of the pole piece areas, the number of the cutting areas is two, and the cutting areas are located on the two outer sides of the pole piece areas.

5. The pole piece tape stock of claim 1, wherein: the number of the pole piece regions is multiple, and the multiple rows of the pole piece regions are distributed along the length direction of the foil; the number of the polar lug regions is multiple, and the multiple rows of the polar lug regions are distributed along the length direction of the foil; the number of the cutting areas is multiple, and the cutting areas and the pole lug areas are alternately arranged on the outer side of the pole piece area along the length direction of the foil.

6. The pole piece tape stock of claim 5, wherein: and a slitting area is further arranged between two adjacent pole piece areas of the foil, and a second auxiliary coating is coated on the slitting area.

7. The pole piece tape stock of claim 6, wherein: the second auxiliary coating is a graphene coating or a silicon dioxide coating; or the second auxiliary coating comprises a graphene coating coated on the cutting area and a silicon dioxide coating coated on the outer side of the graphene layer.

8. A pole piece tape according to any one of claims 1 to 7, wherein: the active material layers are respectively coated on two surfaces of the pole piece region; and/or the two surfaces of the cutting area are respectively coated with the first auxiliary coating.

9. Pole piece monomer, its characterized in that: the pole piece monomer is cut from the pole piece belt material according to any one of claims 1 to 8.

10. A battery, characterized in that: the battery includes the pole piece cell of claim 9.