CN116410678A

CN116410678A - Hot melt adhesive and preparation method thereof, pole piece and preparation method thereof, battery and electricity utilization device

Info

Publication number: CN116410678A
Application number: CN202310683197.2A
Authority: CN
Inventors: 赵利亚; 王龙; 刘会会
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2023-06-09
Filing date: 2023-06-09
Publication date: 2023-07-11

Abstract

The application discloses a hot melt adhesive and a preparation method thereof, a pole piece and a preparation method thereof, a battery and an electric device, wherein the hot melt adhesive comprises 50-100 parts by weight of polyolefin resin and 5-40 parts by weight of insulating particles; wherein the polyolefin resin has a relative molecular mass of 30 to 100 tens of thousands. Therefore, the cohesiveness of the hot melt adhesive is improved, the service life of the hot melt adhesive is prolonged, the cutting yield in the pole piece cutting process is improved, and the production efficiency is improved.

Description

Hot melt adhesive and preparation method thereof, pole piece and preparation method thereof, battery and electricity utilization device

Technical Field

The application relates to the technical field of batteries, in particular to a hot melt adhesive and a preparation method thereof, a pole piece and a preparation method thereof, a battery and an electric device.

Background

The secondary battery is widely used not only in energy storage power supply systems such as hydraulic power, thermal power, wind power and solar power stations, but also in electric vehicles such as electric bicycles, electric motorcycles and electric automobiles, as well as in a plurality of fields such as military equipment and aerospace. The tab is an important component of the battery and is used for connecting the battery pole piece with the external pole of the battery. In order to prevent the tab from being in direct contact with the main body of the battery cell, so that the short circuit is not easy to occur inside the battery cell, an insulating layer is generally arranged in the tab area to prevent the tab from being in direct contact with the main body of the battery cell. However, the pole piece provided with the insulating layer is easy to generate bulging edges or virtual edges in the preparation process, so that the excellent rate of pole piece preparation is reduced, and the production efficiency is reduced.

Disclosure of Invention

In view of the technical problems in the background technology, the application provides a hot melt adhesive, which can reduce the problem that the pole piece has a bulging edge or a virtual edge.

To achieve the above object, a first aspect of the present application provides a hot melt adhesive comprising: 50 to 100 parts by weight of a polyolefin resin and 5 to 40 parts by weight of insulating particles; wherein the polyolefin resin has a relative molecular mass of 30 to 100 tens of thousands.

The hot melt adhesive formed by the application does not contain volatile solvents, when the hot melt adhesive is arranged in the lug area to serve as an insulating layer, the problem that the solvent volatilizes to drive insulating particles to migrate to other areas of a current collector to cause virtual edges or bulging edges can be reduced, and the preparation rate of pole pieces can be improved. The hot melt adhesive has good electrolyte resistance, is not easy to generate oxidation-reduction reaction in the process of charging and discharging the battery, and can prolong the service life of the pole piece. Meanwhile, the hot melt adhesive can meet the insulation requirement of the pole piece, the cutting yield is improved in the pole piece cutting process, adhesion is prevented, and the pole piece production efficiency is improved.

In some embodiments, the polyolefin resin has a relative molecular mass of 30 to 50 tens of thousands. Therefore, the electrolyte resistance of the hot melt adhesive can be improved, the probability of oxidation-reduction reaction of polyolefin resin in the charge-discharge process is reduced, the cutting difficulty is reduced, and the service life of the pole piece is prolonged.

In some embodiments, the hot melt adhesive comprises: 50 to 90 parts by weight of the polyolefin resin, 10 to 30 parts by weight of the insulating particles. Therefore, the cohesiveness and insulating property of the hot melt adhesive can be improved, and the yield in the pole piece cutting process can be improved.

In some embodiments, the polyolefin resin has a melting point of 130 ℃ to 150 ℃. Thus, the flexibility of the polyolefin resin can be improved and the adhesiveness of the hot melt adhesive can be improved.

In some embodiments, the insulating particles have a particle size D _v 50 is less than or equal to 3 mu m. Therefore, the insulating particles with the particle size are uniformly dispersed in the hot melt adhesive, and the cutting yield in the pole piece cutting process can be improved.

In some embodiments, the insulating particles comprise at least one of boehmite, ceramic powder, and aluminum oxide powder. Thereby, the insulation performance of the hot melt adhesive is improved.

In some embodiments, the hot melt adhesive further comprises: 1 to 10 parts by weight of light-absorbing particles. Therefore, energy can be better absorbed in the pole piece cutting process, and the cutting yield in the pole piece cutting process is improved.

In some embodiments, the absorbance of the light absorbing particles is from 0.2 to 0.8. Therefore, the light absorption capacity of the hot melt adhesive is improved, and the cutting yield in the pole piece cutting process is improved.

In some embodiments, the light absorbing particles have a particle size of 5 μm.ltoreq.D _v 50-10 μm. Therefore, the cutting yield in the pole piece cutting process can be improved.

In some embodiments, the light absorbing particles comprise at least one of carbon black, graphite, graphene, and carbon nanotubes. Therefore, the cutting yield in the pole piece cutting process can be improved.

In some embodiments, the hot melt adhesive further comprises: 1 to 8 parts by weight of a viscosity modifier. This further improves the adhesion of the hot melt adhesive.

In some embodiments, the viscosity modifier comprises at least one of microcrystalline wax, paraffin wax, polyethylene wax, and synthetic wax. Thus, the adhesiveness of the hot melt adhesive can be improved.

In some embodiments, the hot melt adhesive further comprises: 0.1 to 1 part by weight of an antioxidant. Thus, the oxidation resistance of the hot melt adhesive can be improved.

In some embodiments, the antioxidant comprises at least one of N-phenyl- β -naphthylamine, 2, 6-di-tert-butyl-p-cresol, 3-methyl-6-tert-butylphenol, pentaerythritol tetrakis [ β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ]. Thus, the oxidation resistance of the hot melt adhesive can be improved.

In a second aspect, the present application provides a method of preparing a hot melt adhesive comprising: uniformly mixing 50-100 parts by weight of polyolefin resin and 5-40 parts by weight of insulating particles to obtain the hot melt adhesive, wherein the polyolefin resin has a relative molecular mass of 30-100 ten thousand.

Therefore, the hot melt adhesive prepared by the method has good electrolyte resistance and good bonding performance with the pole piece, and when the hot melt adhesive is arranged in the lug area to serve as an insulating layer, the problem that the solvent volatilizes to drive insulating particles to migrate to other areas of the current collector to cause virtual edges or bulging edges can be reduced, so that the preparation rate of the pole piece is improved.

In some embodiments, the method of preparing the polyolefin resin includes: the bulk resin and the tackifier are mixed and heated to obtain the polyolefin resin. Therefore, the electrolyte resistance of the polyolefin resin is improved, the polyolefin resin is prevented from undergoing oxidation-reduction reaction in the charge-discharge process of the battery, and the service life of the hot melt adhesive is prolonged.

In some embodiments, the method satisfies at least one of the following conditions: comprising 10 to 50 parts by weight of the host resin; comprises 10 to 30 parts by weight of the tackifier. Therefore, the electrolyte resistance, the adhesiveness and the toughness of the polyolefin resin are further improved, and the probability of oxidation-reduction reaction of the polyolefin resin in the charge-discharge process of the battery is reduced.

In some embodiments, the host resin has a relative molecular mass of 10 to 50 tens of thousands. Therefore, the adhesiveness and toughness of the hot melt adhesive are improved, the electrolyte resistance of the polyolefin resin is improved, and the probability of oxidation-reduction reaction of the polyolefin resin in the charge-discharge process is reduced.

In some embodiments, the bulk resin has a glass transition temperature of-45 ℃ to 25 ℃. Thereby improving the adhesion and toughness of the polyolefin resin to the substrate, improving the electrolyte resistance of the polyolefin resin, the probability of oxidation-reduction reaction of the polyolefin resin in the charge-discharge process is reduced.

In some embodiments, the host resin comprises a polyolefin. Therefore, the adhesiveness and toughness of the polyolefin resin can be improved, the electrolyte resistance of the polyolefin resin can be improved, and the probability of oxidation-reduction reaction of the polyolefin resin in the charge-discharge process can be reduced.

In some embodiments, the polyolefin comprises at least one of an alpha-olefin copolymer, an ethylene-vinyl acetate copolymer, a styrene-isoprene-styrene block copolymer, a styrene-butadiene-styrene block copolymer, a styrene-ethylene-butylene-styrene block copolymer, and an ethylene acrylic acid copolymer. Therefore, the adhesiveness and toughness of the polyolefin resin can be effectively improved, the electrolyte resistance of the polyolefin resin is improved, and the probability of oxidation-reduction reaction of the polyolefin resin in the charge-discharge process is reduced.

In some embodiments, the tackifier has a relative molecular mass of 1000 to 10000. Thereby improving the adhesion between the hot melt adhesive and the current collector.

In some embodiments, the viscosity of the tackifier is 200mPa at 100deg.C ^. S-1000mPa ^. S, S. Thereby, the adhesion between the hot melt adhesive and the current collector is further improved.

In some embodiments, the tackifier comprises at least one of a hydrogenated petroleum resin, a C3 petroleum resin, a C5 petroleum resin, a C9 petroleum resin, a terpene resin, an oleoresin, and dicyclopentadiene. Thereby, the adhesion between the hot melt adhesive and the current collector is further improved.

In some embodiments, further comprising: at least one of a polar modifier and an elastomer is mixed with the host resin and the tackifier and heated to obtain the polyolefin resin. Therefore, polarity can be provided for the hot melt adhesive, the adhesive force between the hot melt adhesive and the current collector is improved, the toughness of the hot melt adhesive can be improved, and the risk of fracture of the hot melt adhesive is reduced.

In some embodiments, the method comprises: 1 to 10 parts by weight of the polar modifier. Therefore, polarity can be provided for the hot melt adhesive, and the bonding force between the hot melt adhesive and the current collector is improved.

In some embodiments, the polar modifier includes at least one of maleic anhydride, polyisobutylene, polybutadiene, a silane coupling agent, and a quaternary ammonium salt. Therefore, polarity can be provided for the hot melt adhesive, and the bonding force between the hot melt adhesive and the current collector is improved.

In some embodiments, the method comprises: 10 to 30 parts by weight of said elastomer. Therefore, the toughness of the hot melt adhesive can be improved, and the risk of fracture of the hot melt adhesive is reduced.

In some embodiments, the elastomer has a relative molecular mass of 10 to 50 tens of thousands. Therefore, the toughness of the hot melt adhesive is improved, and the risk of fracture of the hot melt adhesive is reduced.

In some embodiments, the elastomer comprises: at least one of sodium 2-bromoethyl sulfonate, styrene-isoprene-styrene block copolymer, styrene-butadiene-styrene block copolymer, styrene-ethylene-butylene-styrene block copolymer, ethylene acrylic acid copolymer, styrene butadiene rubber and nitrile rubber. Therefore, the toughness of the hot melt adhesive can be effectively improved, and the risk of fracture of the hot melt adhesive is reduced.

A third aspect of the present application provides a pole piece comprising the hot melt adhesive of the first aspect of the present application or the hot melt adhesive prepared by the method of the second aspect of the present application. Therefore, the service life of the pole piece is prolonged.

In some embodiments, the pole piece comprises: the pole piece body comprises a first area, a second area and a blank area, wherein the second area is arranged on one side of the first area, the blank area is arranged on one side, far away from the first area, of the second area, the first area is provided with an active material layer, the second area is provided with an insulating layer, and the insulating layer comprises the hot melt adhesive; and the tab is arranged at one end of the blank area, which is far away from the second area. Therefore, in the winding process of the battery cell, the hot melt adhesive can isolate the electrode lug from the battery cell body, and the risk of short circuit caused by direct contact between the electrode lug and the battery cell body is reduced.

In some embodiments, the first region has a width H ₁ The width of the second region is H ₂ The width of the blank area is H ₃ ，H ₁ :H ₂ :H ₃ = (18-22): (0.5-1.5): (1-3). Therefore, the energy density of the battery is improved while the contact between the electrode lug and the battery core body is prevented.

In some embodiments, H ₁ 、H ₂ And H ₃ At least one of the following conditions is satisfied: h is 50mm or less ₁ ≤300mm；0＜H ₂ ≤15mm；0＜H ₃ Less than or equal to 30mm. Therefore, the energy density of the battery is improved while the contact between the electrode lug and the battery core body is prevented.

In some embodiments, the active material layer has a thickness T ₁ The thickness of the insulating layer is T ₂ ，T ₁ :T ₂ = (1.5-3): (0.5-1.5). Therefore, the energy density of the battery is improved while the contact between the electrode lug and the battery core body is prevented.

In some embodiments, T ₁ And T ₂ At least one of the following conditions is satisfied: t is more than 0 ₁ ≤125μm；0＜T ₂ Less than or equal to 50 mu m. Therefore, the energy density of the battery is improved while the contact between the electrode lug and the battery core body is prevented.

A fourth aspect of the present application provides a method of making a pole piece as described in the third aspect of the present application, comprising: providing a current collector, wherein the current collector comprises a current collector body and a tab, the current collector body comprises a first area, a second area and a blank area, the second area is arranged on one side of the first area, the blank area is arranged on one side of the second area far away from the first area, the tab is arranged on one end of the blank area far away from the second area, and active material slurry is applied to the first area; and applying hot melt adhesive to the second region.

Therefore, the hot melt adhesive does not contain volatile solvents, when the hot melt adhesive is arranged in the lug area to serve as an insulating layer, the problem that the solvent volatilizes to drive insulating particles to migrate to other areas of the current collector to cause virtual edges or bulging edges can be reduced, and the preparation rate of the pole pieces is improved. The hot melt adhesive has good electrolyte resistance, is not easy to generate oxidation-reduction reaction in the process of charging and discharging the battery, and can prolong the service life of the pole piece. Meanwhile, the hot melt adhesive can meet the insulation requirement of the pole piece, the cutting yield is improved in the pole piece cutting process, adhesion is prevented, and the pole piece production efficiency is improved.

In some embodiments, the method further comprises: the current collector is dried prior to the application of the hot melt adhesive in the second zone. Therefore, the hot melt adhesive is applied to the die cutting section after the drying process is finished, the problem of virtual edges or bulging edges caused by migration of insulating particles to the first area in the drying process can be reduced, the yield of pole piece preparation is improved, and the production efficiency of the pole piece is improved.

A fifth aspect of the present application provides a battery comprising a pole piece as described in the third aspect of the present application or a pole piece prepared by a method as described in the fourth aspect of the present application. Thus, the battery has a long life.

A sixth aspect of the present application provides an electrical device comprising a battery as described in the fifth aspect of the present application. Thus, the power utilization device has a long life.

Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to designate like parts throughout the accompanying drawings. In the drawings:

FIG. 1 is a schematic structural view of a pole piece of an embodiment of the present application at one view;

FIG. 2 is a schematic view of another view of the pole piece of FIG. 1;

fig. 3 is a schematic structural view of a battery according to an embodiment of the present application;

fig. 4 is a schematic structural view of a battery module according to an embodiment of the present application;

fig. 5 is a schematic structural view of a battery pack according to an embodiment of the present application;

FIG. 6 is an exploded view of FIG. 5;

fig. 7 is a schematic diagram of an embodiment of an electrical device with a battery as a power source.

Reference numerals illustrate:

10: a pole piece; 110: a pole piece body; 1101: a first region; 1102: a second region; 1103: blank area; 120: a tab; 1: a secondary battery; 2: a battery module; 3: a battery pack; 4: an upper case; 5: and a lower box body.

Detailed Description

Embodiments of the technical solutions of the present application are described in detail below. The following examples are only for more clearly illustrating the technical solutions of the present application, and thus are only examples, and are not intended to limit the scope of protection of the present application.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

For simplicity, only a few numerical ranges are specifically disclosed herein. However, any lower limit may be combined with any upper limit to form a range not explicitly recited; and any lower limit may be combined with any other lower limit to form a range not explicitly recited, and any upper limit may be combined with any other upper limit to form a range not explicitly recited. Furthermore, each separately disclosed point or individual value may itself be combined as a lower limit or upper limit with any other point or individual value or with other lower limit or upper limit to form a range not explicitly recited.

In the description of the embodiments of the present application, the term "and/or" is merely an association relationship describing an association object, which means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description and claims of the present application and in the description of the figures above are intended to cover non-exclusive inclusions.

Currently, the application of secondary batteries is more widespread in view of the development of market situation. The secondary battery is widely used not only in energy storage power supply systems such as hydraulic power, thermal power, wind power and solar power stations, but also in electric vehicles such as electric bicycles, electric motorcycles and electric automobiles, as well as in a plurality of fields such as military equipment and aerospace. With the continuous expansion of the application field of secondary batteries, the market demand thereof is also continuously expanding.

The tab is an important component of the battery and is used for connecting the battery pole piece with the external pole of the battery. In the battery cell winding structure, an insulating layer is arranged in a lug area of the pole piece, and after the lug is bent, the insulating layer can separate the lug body from the battery cell body, so that the probability of short circuit caused by direct contact between the lug and the battery cell body is reduced. However, when the insulating layer is coated on the coating section, the phenomena of edge bulging and edge deficiency are easy to occur, the rate of excellent pole piece preparation is reduced, and the production efficiency is reduced.

In order to avoid the phenomena of edge bulging and virtual edges of the pole piece, the hot melt adhesive formed by the method is used as an insulating layer, the hot melt adhesive does not contain volatile solvents, when the hot melt adhesive is arranged in a lug area to serve as the insulating layer, the problem that the solvent volatilizes to drive insulating particles to migrate to other areas of a current collector to cause virtual edges or edge bulging can be reduced, and the preparation rate of the pole piece is improved. The hot melt adhesive has good electrolyte resistance, is not easy to generate oxidation-reduction reaction in the process of charging and discharging the battery, and can prolong the service life of the pole piece. Meanwhile, the hot melt adhesive can meet the insulation requirement of the pole piece, the cutting yield is improved in the pole piece cutting process, adhesion is prevented, and the pole piece production efficiency is improved.

The hot melt adhesive disclosed in the embodiments of the present application can be used for a battery, and the battery disclosed in the embodiments of the present application can be used for an electric device using the battery as a power source or various energy storage systems using the battery as an energy storage element. The powered device may include, but is not limited to, a cell phone, tablet, notebook computer, electric toy, electric tool, battery car, electric car, ship, spacecraft, and the like. Among them, the electric toy may include fixed or mobile electric toys, such as game machines, electric car toys, electric ship toys, electric plane toys, and the like, and the spacecraft may include planes, rockets, space planes, and spacecraft, and the like.

The first aspect of the present application provides a hot melt adhesive comprising 50 to 100 parts by weight of a polyolefin resin and 5 to 40 parts by weight of insulating particles; wherein the polyolefin resin has a relative molecular mass of 30 to 100 tens of thousands.

The hot melt adhesive does not contain volatile solvents, when the hot melt adhesive is arranged in a lug area to serve as an insulating layer, the problem that the solvent volatilizes to drive insulating particles to migrate to other areas of a current collector to cause virtual edges or bulging edges can be reduced, and the preparation rate of pole pieces is improved. The hot melt adhesive has good electrolyte resistance, is not easy to generate oxidation-reduction reaction in the process of charging and discharging the battery, and can prolong the service life of the pole piece. Meanwhile, the hot melt adhesive can meet the insulation requirement of the pole piece, the cutting yield is improved in the pole piece cutting process, adhesion is prevented, and the pole piece production efficiency is improved.

In the application, the "tab region" refers to a region where a tab is disposed on a current collector, and the "virtual edge" is formed by coating an insulating layer slurry between an active material layer of the current collector and the tab, and then volatilizing a solvent in the insulating layer slurry, and migrating particles in the insulating layer slurry to the tab region.

In some embodiments, the hot melt adhesive comprises 50 parts by weight to 100 parts by weight of a polyolefin resin, for example, comprising 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 95 parts by weight, or 100 parts by weight of a polyolefin resin, or may be in the range of any of the numerical compositions described above. Therefore, the electrolyte resistance of the hot melt adhesive can be improved by adopting the polyolefin resin with the content of the application, so that the hot melt adhesive is not easy to undergo oxidation-reduction reaction in the battery charging and discharging process, and the service life of the hot melt adhesive is prolonged. In other embodiments, the hot melt adhesives of the present application comprise from 50 to 90 parts by weight of the polyolefin resin.

In some embodiments, the polyolefin resin in the hot melt adhesive has a relative molecular mass of 30 to 100 tens of thousands. For example, the polyolefin resin may have a relative molecular mass of 30 ten thousand, 40 ten thousand, 50 ten thousand, 60 ten thousand, 70 ten thousand, 80 ten thousand, 90 ten thousand, 100 ten thousand, or the like, or may be in a range of any of the numerical compositions mentioned above. From this, adopt the polyolefin resin that satisfies this application relative molecular weight, can improve the electrolyte resistance of hot melt adhesive and with the cohesiveness of current collector, prevent that hot melt adhesive from taking place to drop at battery cycle in-process, in the pole piece cutting process, can improve sliced roughness, reduce the probability that the glue overflows, improve the cutting yield. In addition, the adhesive probability can be reduced in the pole piece winding process. In other embodiments, the polyolefin resin in the hot melt adhesive may have a relative molecular mass of 30 to 50 tens of thousands.

In some embodiments, the polyolefin resin may have a melting point of 130 ℃ to 150 ℃. For example, the melting point of the polyolefin resin may be 130 ℃, 133 ℃, 136 ℃, 139 ℃, 141 ℃, 144 ℃, 147 ℃ or 150 ℃, etc., or may be in the range of any of the above numerical compositions. Therefore, the flexibility of the hot melt adhesive and the cohesiveness of the hot melt adhesive with a current collector can be improved, and the service life of the pole piece is prolonged.

In the present application, "melting point of the polyolefin resin" is a meaning well known in the art, and can be measured by an instrument and a method well known in the art, for example, by differential scanning calorimetry with reference to GB/T19466.2, a heating rate of 10 ℃/min, and a nitrogen atmosphere.

In some embodiments, the hot melt adhesive comprises from 5 parts by weight to 40 parts by weight of insulating particles, for example, comprising 5 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, or 40 parts by weight of insulating particles, or can be in the range of any of the numerical compositions described above. Therefore, the insulating particles with the content can meet the insulating requirement of hot melt adhesive, improve the cutting yield in the pole piece cutting process, prevent adhesion and improve the pole piece production efficiency. In other embodiments, the hot melt adhesive includes 10 parts by weight to 30 parts by weight of insulating particles.

In some embodiments, the insulating particles have a particle size D _v 50 is less than or equal to 3 mu m. Therefore, by adopting the insulating particles with the particle size, the uniformity of the insulating particles in the hot melt adhesive can be improved, the yield of the pole piece in the cutting process is improved, the scratch of the hot melt adhesive in the process of applying the hot melt adhesive on a current collector is prevented, and the production efficiency of the pole piece is improved.

In the present application, the insulating particles have a particle diameter D _v 50 refers to the particle size corresponding to a cumulative volume distribution percentage of 50%, and is measured by a laser particle size analyzer (for example, malvern Master Size 3000) with reference to, for example, standard GB/T19077-2016.

In some embodiments, the insulating particles may include at least one of boehmite, ceramic powder, and aluminum oxide powder. Therefore, by adopting the insulating particles formed by the method, the yield in the pole piece cutting process can be improved and the production efficiency of the pole piece can be improved while the insulating performance of the hot melt adhesive is met.

In some embodiments, the hot melt adhesive may further include: 1 to 10 parts by weight of light-absorbing particles. For example, it may be 1 part by weight, 2 parts by weight, 4 parts by weight, 6 parts by weight, 8 parts by weight, 10 parts by weight, or the like, or may be in a range of any of the above numerical compositions. Therefore, the light absorption particles with the content can improve the light absorption performance of the hot melt adhesive, and can absorb energy better in the pole piece cutting process so that the pole piece is cut off instantly, thereby improving the cutting yield and the production efficiency. In some embodiments, the hot melt adhesive comprises 1 to 5 parts by weight of the light absorbing particles.

In some embodiments, the absorbance of the light absorbing particles may be from 0.2 to 0.8. For example, the absorbance of the light absorbing particles may be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or 0.8, etc., or may be in the range of any of the numerical compositions described above. Therefore, the absorbance light-absorbing particles can improve the absorbance capacity of the hot melt adhesive, and the pole piece can absorb energy better in the pole piece cutting process so as to cut off the pole piece instantly, thereby improving the cutting yield.

In some embodiments, the light absorbing particles have a particle size of 5 μm.ltoreq.D _v 50-10 μm. For example, it may be 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm, etc., or it may be in the range of any of the above-mentioned numerical compositions. Therefore, by adopting the light absorption particles with the particle size, the uniformity of the light absorption particles in the hot melt adhesive can be improved, the whole light absorption capacity of the hot melt adhesive is improved, the pole piece can be cut off instantly by absorbing energy better in the pole piece cutting process, and the cutting yield is improved.

In the present application, the particle diameter D of the light-absorbing particles _v 50 refers to the particle size corresponding to a cumulative volume distribution percentage of 50%, and is measured by a laser particle size analyzer (for example, malvern Master Size 3000) with reference to, for example, standard GB/T19077-2016.

In some embodiments, the light absorbing particles may include at least one of carbon black, graphite, graphene, and carbon nanotubes. Therefore, the light absorption particles can improve the light absorption capacity of the hot melt adhesive, and the pole piece can absorb energy better in the pole piece cutting process so that the pole piece is cut off instantly, thereby improving the cutting yield.

In some embodiments, the hot melt adhesive may further include 1 to 8 parts by weight of a viscosity modifier. For example, it may be 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, or the like, or may be in a range of any of the numerical compositions described above. Therefore, the viscosity regulator with the content can improve the viscosity of the hot melt adhesive and reduce the falling probability of the hot melt adhesive in the battery circulation process.

In some embodiments, the viscosity modifier may include at least one of microcrystalline wax, paraffin wax, polyethylene wax, and synthetic wax. Wherein the microcrystalline wax comprises at least one of microcrystalline wax 50#, microcrystalline wax 60#, microcrystalline wax 70# and microcrystalline wax 80 #. Therefore, the viscosity of the hot melt adhesive is improved, and the falling probability of the hot melt adhesive in the service life period is reduced.

In some embodiments, the hot melt adhesive may further include: the antioxidant may be 0.1 to 1 part by weight, for example, 0.1 part by weight, 0.2 part by weight, 0.3 part by weight, 0.4 part by weight, 0.5 part by weight, 0.6 part by weight, 0.7 part by weight, 0.8 part by weight, 0.9 part by weight, or 1 part by weight, or the like, or may be in a range of any of the above numerical compositions. Therefore, the antioxidant with the content can improve the oxidation resistance of the hot melt adhesive and prolong the service life of the hot melt adhesive.

In some embodiments, the antioxidant comprises at least one of N-phenyl- β -naphthylamine, 2, 6-di-tert-butyl-p-cresol, 3-methyl-6-tert-butylphenol, pentaerythritol tetrakis [ β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ].

Therefore, the hot melt adhesive prepared by the method does not contain volatile solvents, when the hot melt adhesive is arranged in the lug area to serve as an insulating layer, the problem that the solvent volatilizes to drive insulating particles to migrate to other areas of the current collector to cause virtual edges or bulging edges can be reduced, and the preparation rate of the pole pieces is improved. The hot melt adhesive has good electrolyte resistance, is not easy to generate oxidation-reduction reaction in the process of charging and discharging the battery, and can prolong the service life of the pole piece. Meanwhile, the hot melt adhesive can meet the insulation requirement of the pole piece, the cutting yield is improved in the pole piece cutting process, adhesion is prevented, and the pole piece production efficiency is improved.

In some embodiments, the above-mentioned polyolefin resin and the insulating particles may be mixed and stirred to uniformly mix the polyolefin resin and the insulating particles, and the hot melt adhesive may be obtained by filling and discharging. In other embodiments, when the hot melt adhesive further includes at least one of light absorbing particles, a viscosity modifier and an antioxidant, the polyolefin resin and the insulating particles may be simultaneously mixed with at least one of the light absorbing particles, the viscosity modifier and the antioxidant, uniformly stirred, and discharged. Specifically, the speed and time of stirring are not particularly limited, and for example, 1000rpm to 1400rpm may be first stirred for 50min to 70min, and 600rpm to 1000rpm may be then stirred for 80min to 100min.

In some embodiments, a method of preparing the polyolefin resin may include: the bulk resin and the tackifier are mixed and heated to obtain the polyolefin resin. Therefore, the prepared polyolefin resin has good electrolyte resistance, is not easy to generate oxidation-reduction reaction in the charge and discharge process of the battery, can further improve the cohesiveness of the hot melt adhesive and the current collector when being coated on the current collector, reduces the risk of falling off of the hot melt adhesive in the use process, and prolongs the service life of the hot melt adhesive.

In some specific embodiments, the polyolefin resin is prepared to include 10 to 50 parts by weight of the host resin, for example, 10 parts by weight, 12 parts by weight, 16 parts by weight, 20 parts by weight, 24 parts by weight, 28 parts by weight, 32 parts by weight, 36 parts by weight, 40 parts by weight, 44 parts by weight, or 50 parts by weight, etc., or may be in the range of any of the numerical compositions described above. Therefore, the electrolyte resistance of the polyolefin resin is improved, the polyolefin resin is prevented from undergoing oxidation-reduction reaction in the charging and discharging process of the battery, and the service life of the hot melt adhesive is prolonged.

In some embodiments, the host resin may have a relative molecular mass of 10 to 50 tens of thousands. For example, it may be 10 tens of thousands, 14 tens of thousands, 18 tens of thousands, 22 tens of thousands, 26 tens of thousands, 30 tens of thousands, 34 tens of thousands, 38 tens of thousands, 42 tens of thousands, 46 tens of thousands or 50 tens of thousands, etc., or may be a range of any of the above-mentioned numerical compositions. Therefore, the adhesiveness of the hot melt adhesive and the current collector is improved, the probability of falling off of the hot melt adhesive in the service life period is reduced, and the electrolyte resistance of the polyolefin resin is improved.

In some embodiments, the glass transition temperature of the host resin may be from-45 ℃ to 25 ℃. For example, it may be-45 ℃, -40 ℃, -35 ℃, -30 ℃, -25 ℃, -20 ℃, -15 ℃, -10 ℃, -5 ℃, 0 ℃, 5 ℃, 10 ℃, 15 ℃, 20 ℃, 25 ℃ or the like, or it may be in a range of any of the above numerical compositions. Therefore, the adhesiveness and toughness of the polyolefin resin are improved, the electrolyte resistance of the polyolefin resin is improved, the oxidation-reduction reaction of the polyolefin resin in the charge-discharge process is prevented, and the service life of the hot melt adhesive is prolonged.

In some embodiments, the host resin comprises a polyolefin. In some specific embodiments, the polyolefin may include at least one of an alpha-olefin copolymer (APAO), an ethylene-vinyl acetate copolymer, a styrene-isoprene-styrene block copolymer, a styrene-butadiene-styrene block copolymer, a styrene-ethylene-butylene-styrene block copolymer, and an ethylene acrylic acid copolymer. Therefore, the adhesiveness and toughness of the polyolefin resin can be effectively improved, the electrolyte resistance of the polyolefin resin is improved, and the polyolefin resin is prevented from undergoing oxidation-reduction reaction in the charge-discharge process. In some embodiments, the host resin may include an alpha-olefin copolymer.

In some embodiments, the polyolefin resin may be prepared to include 10 to 30 parts by weight of the tackifier, for example, 10 parts by weight, 12 parts by weight, 14 parts by weight, 16 parts by weight, 18 parts by weight, 20 parts by weight, 22 parts by weight, 24 parts by weight, 26 parts by weight, 28 parts by weight, 30 parts by weight, or the like, or may be in the range of any of the above numerical compositions. Therefore, the cohesiveness of the hot melt adhesive and the current collector is improved, and the falling probability of the hot melt adhesive in the service life period is reduced.

In some embodiments, the tackifier may have a relative molecular mass of 1000 to 10000. For example, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000 or 10000, etc. may be mentioned, or may be in the range of any of the above numerical compositions. Thus, the adhesiveness of the polyolefin resin is improved, and the adhesion between the hot melt adhesive and the current collector is improved.

In some embodiments, the viscosity of the tackifier may be 200mPa at 100deg.C ^. S-1000mPa ^. S, S. For example, it may be 200mPa ^. S、300mPa ^. S、400mPa ^. S、500mPa ^. S、600mPa ^. S、700mPa ^. S、800mPa ^. S、900mPa ^. S or 1000mPa ^. S, etc., or may be in the range of any of the numerical compositions described above. Thus, the adhesiveness of the polyolefin resin is further improved, and the adhesion between the hot melt adhesive and the current collector is improved.

In this application, "viscosity of a tackifier" is a meaning well known in the art and can be measured using instruments and methods well known in the art, for example, test methods can be referenced to GBT 1548-2004.

In some embodiments, the tackifier may include at least one of hydrogenated petroleum resin, C3 petroleum resin, C5 petroleum resin, C9 petroleum resin, terpene resin, oleoresin, and dicyclopentadiene. Thereby, the adhesion between the hot melt adhesive and the current collector is further improved. In other embodiments, the tackifier may comprise a C5 petroleum resin.

The C3 petroleum resin in the application refers to thermoplastic resin prepared by taking a byproduct C3 fraction of a cracking ethylene preparation device as a main raw material, polymerizing in the presence of a catalyst, or copolymerizing the byproduct C3 fraction with anhydride, phenols and aromatic hydrocarbon compounds; the C5 petroleum resin is thermoplastic resin prepared by taking a byproduct C5 fraction of a pyrolysis ethylene preparation device as a main raw material and polymerizing the main raw material in the presence of a catalyst or copolymerizing the main raw material with anhydride, phenol and aromatic hydrocarbon compounds; the C9 petroleum resin is thermoplastic resin prepared by polymerizing by-product C9 fraction of ethylene preparing device as main material in the presence of catalyst or copolymerizing with acid anhydride, phenol and aromatic hydrocarbon.

In other embodiments, the method of preparing the polyolefin resin further comprises: at least one of a polar modifier and an elastomer is mixed with the host resin and the tackifier and heated to obtain the polyolefin resin. Therefore, the polarity of the polyolefin resin can be improved, the cohesiveness between the hot melt adhesive and the current collector can be improved, the toughness of the hot melt adhesive can be improved, and the fracture risk of the hot melt adhesive can be reduced. In some specific embodiments, the method of preparing the polyolefin resin may include: the polar modifier, the host resin, and the tackifier are mixed and heated to obtain the polyolefin resin. In other specific embodiments, the method of preparing the polyolefin resin may include: the elastomer, the host resin and the tackifier are mixed and heated to obtain the polyolefin resin. In other specific embodiments, the method of preparing the polyolefin resin may include: the polar modifier, the elastomer, the host resin and the tackifier are mixed and heated to obtain the polyolefin resin.

In some specific embodiments, when the polyolefin resin is prepared to include the polar modifier, 1 to 10 parts by weight of the polar modifier may be included, for example, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, or the like, or may be in the range of any of the above numerical compositions. Therefore, the polarity of the hot melt adhesive is improved, the cohesiveness of the hot melt adhesive and a current collector is improved, and the probability of falling off of the hot melt adhesive in the service life period is reduced.

In some embodiments, the polar modifier may include at least one of Maleic Anhydride (MAH), polyisobutylene, polybutadiene, a silane coupling agent, and a quaternary ammonium salt. Therefore, polarity can be provided for the hot melt adhesive, and the bonding force between the hot melt adhesive and the current collector is improved. In some embodiments, the polar modifier may include maleic anhydride.

In some embodiments, when the polyolefin resin is prepared to include the elastomer, 10 to 30 parts by weight of the elastomer may be included, for example, 12 to 28 parts by weight of the elastomer, 14 to 26 parts by weight of the elastomer, 16 to 24 parts by weight of the elastomer, 18 to 22 parts by weight of the elastomer, 19 to 21 parts by weight of the elastomer, or the like may be included. Therefore, the toughness of the hot melt adhesive is improved, and the risk of brittle failure of the hot melt adhesive is reduced.

In some embodiments, the elastomer may have a relative molecular mass of 10 to 50 tens of thousands. For example, it may be 10 tens of thousands, 14 tens of thousands, 18 tens of thousands, 22 tens of thousands, 26 tens of thousands, 30 tens of thousands, 34 tens of thousands, 38 tens of thousands, 42 tens of thousands, 46 tens of thousands or 50 tens of thousands, etc., or may be a range of any of the above-mentioned numerical compositions. Therefore, the toughness of the hot melt adhesive is improved, and the risk of fracture of the hot melt adhesive is reduced.

In some embodiments, the elastomer may include: at least one of sodium 2-bromoethyl sulfonate, styrene-isoprene-styrene block copolymer, styrene-butadiene-styrene block copolymer, styrene-ethylene-butylene-styrene block copolymer (SBES), ethylene acrylic acid copolymer, styrene butadiene rubber, and nitrile butadiene rubber. Therefore, the toughness of the hot melt adhesive can be effectively improved, and the risk of fracture of the hot melt adhesive is reduced. In some specific embodiments, the elastomer may include a styrene-ethylene-butylene-styrene block copolymer.

In some embodiments, the method of preparing the polyolefin resin may include: adding the main resin, the polar modifier, the elastomer and the tackifier into a reaction kettle, heating to 140-200 ℃, vacuumizing and stirring for 100-140 min, and obtaining the polyolefin resin. Specifically, the temperature of heating may be 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃, etc., or may be in the range of any of the above numerical compositions. The stirring time may be 100min, 105min, 110min, 115min, 120min, 125min, 130min, 135min, 140min, etc., or may be in the range of any of the above values.

A third aspect of the present application provides a pole piece 10 comprising the hot melt adhesive of the first aspect of the present application or the hot melt adhesive prepared by the method of the second aspect of the present application. Thereby extending the useful life of pole piece 10.

In some embodiments, referring to fig. 1, the pole piece 10 comprises: the pole piece body 110, the pole piece body 110 comprises a first area 1101, a second area 1102 and a blank area 1103, the second area 1102 is arranged on one side of the first area 1101, the blank area 1103 is arranged on one side of the second area 1102 away from the first area 1101, the first area 1101 is provided with an active material layer, the second area 1102 is provided with an insulating layer, and the insulating layer comprises the hot melt adhesive; the tab 120 is disposed at one end of the blank area 1103 away from the second area 1102, where the tab 120 is located. Therefore, in the winding process of the battery cell, the hot melt adhesive can isolate the electrode lug from the battery cell body, and the electrode lug is prevented from being in direct contact with the battery cell body to generate short circuit. Meanwhile, as the hot melt adhesive and the current collector have excellent cohesiveness and toughness, the risk of falling off of the hot melt adhesive in the service life of the pole piece 10 can be reduced, and the insulation effect is achieved in the whole service life of the pole piece 10.

In some embodiments, referring to fig. 1, the first region 1101 may have a width H ₁ The width of the second region 1102 may be H ₂ The width of the blank area 1103 may be H ₃ ，H ₁ :H ₂ :H ₃ = (18-22): (0.5-1.5): (1-3), for example, (19-21): (0.8-1.2): (1.5-2.5), (19.5-20.5): (0.9-1.1): (1.7-2.2) etc., or may be in the range of any of the numerical compositions mentioned above. Therefore, the risk of contact between the electrode lug and the battery core body is reduced, and the energy density of the battery is improved. The width direction of the pole piece 10 is the Y direction in fig. 1.

In some embodiments, H ₁ The method comprises the following steps: h is 50mm or less ₁ Less than or equal to 300mm, e.g. H ₁ Can be 50mm,70mm, 90mm, 110mm, 130mm, 150mm, 170mm, 190mm, 210mm, 230mm, 250mm, 270mm, 290mm or 300mm, etc., or may be in the range of any of the numerical compositions described above. Thereby increasing the active material content of the pole piece 10 and increasing the energy density of the battery.

In some embodiments, H ₂ Can be 0 < H ₂ 15mm or less, e.g. H ₂ May be 1mm, 3mm, 5mm, 7mm, 9mm, 11mm, 13mm, 15mm, etc., or may be in the range of any of the numerical compositions described above. Therefore, the second region 1102 is provided with an insulating layer, the insulating layer comprises hot melt adhesive, and in the winding process of the battery cell, the hot melt adhesive can isolate the electrode lug from the battery cell body, so that the electrode lug is prevented from being in direct contact with the battery cell body to generate short circuit.

In some embodiments, H ₃ Can be 0 < H ₃ 30mm or less, e.g. H ₃ May be 1mm, 4mm, 7mm, 10mm, 13mm, 17mm, 20mm, 23mm, 26mm, 29mm, 30mm, etc., or may be in the range of any of the numerical compositions described above.

In some embodiments, referring to fig. 2, the active material layer has a thickness T ₁ The thickness of the insulating layer is T ₂ ，T ₁ :T ₂ = (1.5-3): (0.5-1.5). For example, (1.7-2.8), (1.7-1.3), (1.9-2.6), (0.9-1.1), (2.1-2.3), (0.9-1.0), etc., or may be in the range of any of the above numerical compositions. Therefore, the risk of contact between the electrode lug and the battery core body is reduced, and the energy density of the battery is improved. The thickness direction of the pole piece 10 is the X direction in fig. 2.

In some embodiments, T ₁ Can be 0 < T ₁ 125 μm or less, for example, may be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm or 125 μm or the like, or may be in a range of any of the above numerical compositions. Thereby increasing the active material content of the pole piece 10 and increasing the energy density of the battery.

In some embodiments, T ₂ Can be 0 < T ₂ 50 μm or less, for example, may be 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm, etc., or may be in the range of any of the numerical compositions described above. Therefore, the second region 1102 is provided with an insulating layer, the insulating layer comprises hot melt adhesive, and in the winding process of the battery cell, the hot melt adhesive can isolate the electrode lug from the battery cell body, so that the electrode lug is prevented from being in direct contact with the battery cell body to generate short circuit.

As an example, the pole piece 10 may include a positive pole piece or a negative pole piece.

In some embodiments, the positive electrode tab includes a positive electrode current collector, which may be a metal foil, a foam metal, or a composite current collector. For example, as the metal foil, silver-surface-treated aluminum or stainless steel, copper, aluminum, nickel, carbon electrode, carbon, titanium, or the like can be used. The composite current collector may include a polymeric material base layer and a metal layer. The foam metal can be foam nickel, foam copper, foam aluminum, foam alloy, foam carbon or the like. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a polymer material substrate (e.g., a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

In some embodiments, the positive electrode sheet may further include a positive electrode active material layer including a positive electrode active material, and the specific kind of the positive electrode active material is not limited, and active materials known in the art to be used for a positive electrode of a battery may be used, and may be selected according to actual needs by those skilled in the art.

As an example, the positive electrode active material may include, but is not limited to, one or more of lithium transition metal oxides, olivine structured lithium-containing phosphates, and their respective modified compounds. Examples of the lithium transition metal oxide may include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt aluminum oxide, and modified compounds thereof. Examples of olivine structured lithium-containing phosphates may include, but are not limited to, one or more of lithium iron phosphate, lithium iron phosphate-carbon composites, lithium manganese phosphate-carbon composites, lithium manganese phosphate-iron, lithium manganese phosphate-carbon composites, and modified compounds thereof. These materials are commercially available.

For example, when the battery is a sodium ion battery, the positive electrode active material may include, but is not limited to, at least one of a layered transition metal oxide, a polyanion compound, and a prussian blue analog, as examples.

Examples of the layered transition metal oxide include:

Na _1-x Cu _h Fe _k Mn _l M ¹ _m O _2-y Wherein M is ¹ Is one or more of Li, be, B, mg, al, K, ca, ti, co, ni, zn, ga, sr, Y, nb, mo, in, sn and Ba, 0<x≤0.33，0<h≤0.24，0≤k≤0.32，0<l≤0.68，0≤m<0.1，h+k+l+m＝1，0≤y<0.2；

Na _0.67 Mn _0.7 Ni _z M ² _0.3-z O ₂ Wherein M is ² Is one or more of Li, mg, al, ca, ti, fe, cu, zn and Ba, 0<z≤0.1；

Na _a Li _b Ni _c Mn _d Fe _e O ₂ Of which 0.67<a≤1，0<b<0.2，0<c<0.3，0.67<d+e<0.8，b+c+d+e＝1。

Examples of the polyanion compound include:

A ¹ _f M ³ _g (PO ₄ ) _i O _j X ¹ _3-j wherein A is ¹ H, li, na, K and NH ₄ One or more of M ³ Is one or more of Ti, cr, mn, fe, co, ni, V, cu and Zn, X ¹ Is one or more of F, cl and Br, 0<f≤4，0<g≤2，1≤i≤3，0≤j≤2；

Na _n M ⁴ PO ₄ X ² Wherein M is ⁴ Is one or more of Mn, fe, co, ni, cu and Zn, X ² F, cl is a combination ofOne or more of Br, 0<n≤2；

Na _p M ⁵ _q (SO ₄ ) ₃ Wherein M is ⁵ Is one or more of Mn, fe, co, ni, cu and Zn, 0<p≤2，0<q≤2；

Na _s Mn _t Fe _3-t (PO ₄ ) ₂ (P ₂ O ₇ ) Wherein 0 is<s.ltoreq.4, 0.ltoreq.t.ltoreq.3, for example t is 0, 1, 1.5, 2 or 3.

As examples of the above prussian blue analogues, for example, there may be mentioned:

A _u M ⁶ _v [M ⁷ (CN) ₆ ] _w ·xH ₂ o, wherein A is H ⁺ 、NH ₄ ⁺ One or more of alkali metal cations and alkaline earth metal cations, M ⁶ And M ⁷ Each independently is one or more of transition metal cations, 0<u≤2，0<v≤1，0<w≤1，0<x<6. For example A is H ⁺ 、Li ⁺ 、Na ⁺ 、K ⁺ 、NH ₄ ⁺ 、Rb ⁺ 、Cs ⁺ 、Fr ⁺ 、Be ²⁺ 、Mg ²⁺ 、Ca ²⁺ 、Sr ²⁺ 、Ba ²⁺ Ra (Ra) ²⁺ One or more of M ⁶ And M ⁷ Each independently is a cation of one or more transition metal elements of Ti, V, cr, mn, fe, co, ni, cu, zn, sn and W.

The modifying compound of each material can be doping modification and/or surface coating modification of the material.

The positive electrode active material layer typically also optionally includes a binder, a conductive agent, and other optional adjuvants.

As an example, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, super P (SP), graphene, and carbon nanofibers.

As an example, the adhesive may include one or more of styrene-butadiene rubber (SBR), aqueous acrylic resin (water-based acrylic resin), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyacrylic acid (PAA), carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB).

In some embodiments, the negative electrode tab includes a negative electrode current collector, which may be a metal foil, a foam metal, or a composite current collector. For example, as the metal foil, silver-surface-treated aluminum or stainless steel, copper, aluminum, nickel, carbon electrode, carbon, titanium, or the like can be used. The foam metal can be foam nickel, foam copper, foam aluminum, foam alloy, foam carbon or the like. The composite current collector may include a polymer material base layer and a metal layer, and may be formed by disposing a metal material (copper, copper alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a polymer material substrate (e.g., a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

In some embodiments, the negative electrode tab may further include a negative electrode active material layer including a negative electrode active material, and the specific kind of the negative electrode active material is not limited, and active materials known in the art to be capable of being used for a negative electrode of a battery may be used, and may be selected according to actual needs by those skilled in the art.

As an example of this, the number of devices, the negative active material may include, but is not limited to, one or more of artificial graphite, natural graphite, hard carbon, soft carbon, silicon-based material, and tin-based material. The silicon-based material may comprise one or more of elemental silicon, silicon oxygen compounds (e.g., silicon oxide), silicon carbon composites, silicon nitrogen composites, and silicon alloys. The tin-based material can comprise one or more of elemental tin, tin oxide and tin alloy. These materials are commercially available.

In some embodiments, in order to further increase the energy density of the battery, the anode active material may include a silicon-based material.

The negative electrode active material layer typically also optionally includes a binder, a conductive agent, and other optional adjuvants.

As an example, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

As an example, the adhesive may include one or more of styrene-butadiene rubber (SBR), aqueous acrylic resin (water-based acrylic resin), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB).

Other optional adjuvants may include, by way of example, thickeners and dispersants (e.g., sodium carboxymethyl cellulose CMC-Na), PTC thermistor materials.

A fourth aspect of the present application provides a method of making a pole piece 10 as described in the third aspect of the present application, comprising: providing a current collector, wherein the current collector comprises a current collector body and a tab, the current collector body comprises a first region 1101, a second region 1102 and a blank region 1103, the second region 1102 is arranged on one side of the first region 1101, the blank region 1103 is arranged on one side of the second region 1102 away from the first region 1101, the tab 120 is arranged on one end of the blank region 1103 away from the second region 1102, and active material slurry is applied to the first region 1101; a hot melt adhesive is applied in the second region 1102. Therefore, the hot melt adhesive does not contain volatile solvents, when the hot melt adhesive is arranged in the lug area to serve as an insulating layer, the problem that the solvent volatilizes to drive insulating particles to migrate to other areas of the current collector to cause virtual edges or bulging edges can be reduced, and the preparation rate of the pole pieces is improved. The hot melt adhesive has good electrolyte resistance, is not easy to generate oxidation-reduction reaction in the process of charging and discharging the battery, and can prolong the service life of the pole piece. Meanwhile, the hot melt adhesive can meet the insulation requirement of the pole piece, the cutting yield is improved in the pole piece cutting process, adhesion is prevented, and the pole piece production efficiency is improved.

In some embodiments, the method further comprises: the current collector is dried prior to the application of the hot melt adhesive in the second region 1102. In some embodiments, the active paste is applied to the current collector, the current collector is dried, and the hot melt adhesive is applied to the current collector after drying, followed by die cutting. In other embodiments, the active slurry is applied to the current collector, the current collector is dried, the current collector is die cut after drying, and the hot melt adhesive is applied to the current collector after die cutting. Therefore, the hot melt adhesive is applied after the drying process is finished, so that the hot melt adhesive is prevented from being heated and softened to flow in the heating and drying process, the probability of virtual edges or bulging edges caused by migration of the hot melt adhesive to the first area 1101 is reduced, the yield of pole piece 10 preparation is improved, and the production efficiency of the pole piece 10 is improved.

A fifth aspect of the present application provides a battery comprising a pole piece 10 as described in the third aspect of the present application or a pole piece 10 prepared by a method as described in the fourth aspect of the present application. Thus, the battery life cycle is longer.

Typically, the battery includes a positive electrode tab 10, a negative electrode tab 10, a separator, and an electrolyte. During the charge and discharge of the battery, active ions are inserted and extracted back and forth between the positive electrode tab 10 and the negative electrode tab 10. The isolating film is arranged between the positive pole piece 10 and the negative pole piece 10 to play a role of isolation. The electrolyte plays a role in conducting ions between the positive electrode tab 10 and the negative electrode tab 10.

The separator is not particularly limited, and any known porous separator having electrochemical stability and mechanical stability may be used according to practical requirements, and may be, for example, a single-layer or multi-layer film comprising one or more of glass fiber, nonwoven fabric, polyethylene, polypropylene and polyvinylidene fluoride.

The electrolyte may include an electrolyte salt and a solvent.

As an example, when the battery is a lithium ion battery, the electrolyte lithium salt may include lithium hexafluorophosphate (LiPF ₆ ) Lithium tetrafluoroborate (LiBF) ₄ ) Lithium perchlorate (LiClO) ₄ ) Lithium hexafluoroarsenate (LiAsF) ₆ ) Lithium bis (fluorosulfonyl) imide (LiLSI), lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalato borate (LiDFOB), lithium dioxaoxalato borate(LiBOB), lithium difluorophosphate (LiPO) ₂ F ₂ ) One or more of lithium difluorooxalate phosphate (LiDFOP) and lithium tetrafluorooxalate phosphate (LiTFOP).

As an example, when the battery is a sodium ion battery, the electrolyte sodium salt includes at least one of sodium hexafluorophosphate, sodium difluorooxalato borate, sodium tetrafluoroborate, sodium bisoxalato borate, sodium perchlorate, sodium hexafluoroarsenate, sodium bis (fluorosulfonyl) imide, sodium trifluoromethylsulfonate, and sodium bis (trifluoromethylsulfonyl) imide.

As an example, the solvent may include one or more of Ethylene Carbonate (EC), propylene Carbonate (PC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), butylene Carbonate (BC), fluoroethylene carbonate (FEC), methyl Formate (MF), methyl Acetate (MA), ethyl Acetate (EA), propyl Acetate (PA), methyl Propionate (MP), ethyl Propionate (EP), propyl Propionate (PP), methyl Butyrate (MB), ethyl Butyrate (EB), 1, 4-butyrolactone (GBL), sulfolane (SF), dimethylsulfone (MSM), methylsulfone (EMS), and diethylsulfone (ESE).

In some embodiments, additives are also included in the electrolyte. For example, the additives may include negative electrode film-forming additives, or may include positive electrode film-forming additives, or may include additives that improve certain properties of the battery, such as additives that improve the overcharge performance of the battery, additives that improve the high temperature performance of the battery, additives that improve the low temperature performance of the battery.

The shape of the battery according to the embodiment of the present application is not particularly limited, and may be cylindrical, square, or any other shape. Fig. 3 shows a secondary battery 1 of a square structure as an example.

In some embodiments, secondary battery 1 may include an outer package. The outer package is used for packaging the positive electrode plate 10, the negative electrode plate 10 and the electrolyte.

In some embodiments, the outer package may include a housing and a cover. Wherein, the casing can include the bottom plate and connect the curb plate on the bottom plate, and bottom plate and curb plate enclose and close and form the chamber that holds. The shell is provided with an opening communicated with the accommodating cavity, and the cover plate can be covered on the opening to seal the accommodating cavity.

The positive electrode sheet 10, the negative electrode sheet 10, and the separator may be formed into an electrode assembly through a winding process or a lamination process. The electrode assembly is encapsulated in the accommodating cavity. The electrolyte is impregnated in the electrode assembly. The number of electrode assemblies included in the battery may be one or several, and may be adjusted according to the needs.

In some embodiments, the exterior package of the battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell.

The outer package of the battery may also be a pouch, such as a pouch-type pouch. The soft bag can be made of plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT) and polybutylene succinate (PBS).

In some embodiments, the cells may be assembled into a battery module, and the number of cells contained in the battery module may be plural, with the specific number being adjustable according to the application and capacity of the battery module.

Fig. 4 is a battery module 2 as an example. Referring to fig. 4, in the battery module 2, a plurality of secondary batteries 1 may be sequentially arranged in the longitudinal direction of the battery module 2. Of course, the arrangement may be performed in any other way. The plurality of secondary batteries 1 may be further fixed by fasteners.

The battery module 2 may further include a case having an accommodating space in which the plurality of secondary batteries 1 are accommodated. In some embodiments, the battery modules may be further assembled into a battery pack, and the number of battery modules included in the battery pack may be adjusted according to the application and capacity of the battery pack.

Fig. 5 and 6 are battery packs 3 as an example. Referring to fig. 5 and 6, a battery case and a plurality of battery modules 2 disposed in the battery case may be included in the battery pack 3. The battery box includes an upper box body 4 and a lower box body 5, and the upper box body 4 can be covered on the lower box body 5 and forms a closed space for accommodating the battery module 2. The plurality of battery modules 2 may be arranged in the battery case in any manner.

A sixth aspect of the present application provides an electrical device comprising a battery as described in the fifth aspect of the present application. Thus, the life cycle of the power utilization device is longer.

As an example, the power consumption device includes at least one of the battery, the battery module, and the battery pack. The battery, battery module or battery pack may be used as a power source for the power device or as an energy storage unit for the power device. The power utilization device may be, but is not limited to, a mobile device (e.g., a cell phone, a notebook computer), an electric vehicle (e.g., a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck), an electric train, a watercraft, a satellite, and an energy storage system.

The electricity consumption device may select the secondary battery 1, the battery module 2, or the battery pack 3 according to the use requirements thereof.

Fig. 7 is an electrical device as an example. The power utilization device comprises a pure electric vehicle, a hybrid electric vehicle or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of the power device for the battery, a battery pack or battery module may be employed.

As another example, the power consumption device may include a cellular phone, a tablet computer, a notebook computer. The power utilization device is required to be light and thin, and a battery can be used as a power source.

In order to make the technical problems, technical schemes and beneficial effects solved by the embodiments of the present application more clear, the following will be described in further detail with reference to the embodiments and the accompanying drawings. It will be apparent that the described embodiments are only some, but not all, of the embodiments of the present application. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, or its uses. All other embodiments, based on the embodiments herein, which are within the scope of the protection of the present application, will be within the skill of one of ordinary skill in the art without undue burden.

1. Preparation of polyolefin resins

The components were weighed according to the compositions and contents of examples 1 to 38 in Table 1, and the reaction vessel was heated to 160℃and stirred for 120 minutes under vacuum to obtain a polyolefin resin.

2. Preparation of hot melt adhesive

The polyolefin resins obtained in examples 1 to 38 were mixed with 20 parts by weight of boehmite, 5 parts by weight of carbon black, 5 parts by weight of microcrystalline wax and 0.2 part by weight of N-phenyl-beta-naphthylamine, respectively, and stirred at 1200 rpm for 60 minutes, followed by 800 rpm for 90 minutes to make the components uniformly mixed, and finally, the mixture was filled and discharged to obtain a hot melt adhesive.

3. Preparation of positive electrode plate

Fully dissolving polyvinylidene fluoride binder in N-methyl pyrrolidone, and adding carbon black conductive agent and anode active material LiNi _0.5 Co _0.25 Mn _0.25 O ₂ Preparing uniformly dispersed positive electrode slurry (the mass ratio of the polyvinylidene fluoride binder, the carbon black conductive agent and the positive electrode active material is 10:10:80), uniformly coating the positive electrode slurry on a first area of the surface of an aluminum foil, transferring a current collector into a vacuum drying oven for complete drying, coating the hot melt adhesive obtained in the embodiment 1-38 on a second area of the surface of the aluminum foil, rolling the obtained pole piece after drying, and then cutting to obtain the positive electrode pole piece.

4. Preparation of negative electrode plate

Artificial graphite, a carbon nano tube material and a binder sodium carboxymethyl cellulose are mixed according to a mass ratio of 8:1:1 adding the mixture into water, stirring to obtain uniform negative electrode slurry, coating the negative electrode slurry on a first area of the surface of a copper foil, transferring a current collector into a vacuum drying oven for complete drying, coating the hot melt adhesive obtained in the embodiment 1-38 on a second area of the surface of the copper foil, drying, and then cutting to obtain a negative electrode plate.

5. Preparation of electrolyte

Ethylene Carbonate (EC) and ethylmethyl carbonate (EMC) were mixed in a mass ratio of 30:70 to obtain an organic solvent, and drying the electrolyte salt LiPF ₆ Is dissolved onIn the organic solvent, the concentration of electrolyte salt is 1.0mol/L, and the electrolyte is obtained after uniform mixing.

6. Cyclic voltammetry test

The mercury/oxidized mercury was used as a reference electrode, a platinum sheet was used as a counter electrode, and the electrolyte was 0.5. 0.5M K ₂ CO ₃ Is a solution of acetonitrile and deuterated water (acetonitrile volume is 33.3% of the total volume of the solution). The cyclic voltammetry test is carried out within the range of the sweeping speed of 10mV/s and the voltage of-0.4V to 5V.

TABLE 1

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Description: if wiredrawing, adhesion or continuous cutting occurs in the pole piece cutting process, the pole piece represents cutting failure; the pole piece can be directly cut off in the pole piece cutting process, and the cutting success is represented when the wire drawing or adhesion does not occur.

Conclusion: as can be seen from Table 2, the polyolefin resin prepared in the application is easy to cut, has good adhesion with a current collector, and a pole piece containing the hot melt adhesive is subjected to cyclic voltammetry, and does not generate oxidation-reduction peaks on CV curves, so that the polyolefin resin has excellent electrolyte resistance.

Examples 39 to 77 and comparative examples 1 to 6

1. Preparation of hot melt adhesive

The components were weighed according to the composition of the hot melt adhesive in example 39 of Table 3, wherein the polyolefin resins obtained in example 38 of Table 3 were used as the polyolefin resins, and were stirred at 1200 rpm for 60 minutes, then at 800 rpm for 90 minutes, so that the components were uniformly mixed, and finally the hot melt adhesive was obtained by filling and discharging.

The hot melt adhesives of examples 40-77, comparative examples 1-6 were prepared in the same manner as in example 39, except that the hot melt adhesive was different in composition, as shown in Table 3. The hot melt adhesives of each example and comparative example were tested for viscosity at 180℃and the test results are shown in Table 4.

2. Preparation of pole piece

Providing a current collector, wherein the current collector is copper foil;

the hot melt adhesive was coated on the copper foil, and the current collector coated with the hot melt adhesive was cut, and the cutting result was recorded, and the cutting result is shown in table 4.

3. Preparation of electrolyte

Ethylene Carbonate (EC) and ethylmethyl carbonate (EMC) were mixed in a mass ratio of 30:70 to obtain an organic solvent, and drying the electrolyte salt LiPF ₆ Dissolving in the mixed solvent, wherein the concentration of electrolyte salt is 1.0mol/L, and uniformly mixing to obtain the electrolyte.

The pole piece coated with the hot melt adhesive was immersed in the electrolyte, and the adhesion between the hot melt adhesive and the pole piece was tested before immersion, for 1 day, for 4 days, and for 7 days, respectively, and the test results are shown in table 4.

The pole piece coated with the hot melt adhesive was laser cut and the cutting results are shown in table 4.

Performance test:

method for testing viscosity at 180 ℃): the glue was filled into a beaker, heated to 180℃and tested with a viscosity tester, specifically referred to GBT 1548-2004.

The method for testing the adhesion force between the hot melt adhesive and the current collector comprises the following steps: the hot melt adhesive was knife coated on a current collector with a thickness of 0.2mm and a width of 20mm, and then tested according to the 180 degree peel force test method of the adhesive tape, and reference is made to GB/T2792-1998.

The laser cutting process comprises the following steps: the laser incident beam is irradiated on the substrate, the laser can rapidly and accurately heat the surface of the aluminum foil, the laser cutting power is 200w-1000w, and the local area is melted, so that the cutting effect is achieved.

TABLE 3 Table 3

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Conclusion: as can be seen from Table 4, after the hot melt adhesives in examples 39 to 77 were immersed for 7 days, the change rate of the adhesive force between the hot melt adhesives and the current collector was significantly lower than that of comparative examples 1 to 6, which means that the adhesive force of the hot melt adhesives in examples 39 to 77 was superior to that of comparative examples 1 to 6, and the cutting yield of the hot melt adhesives in examples 39 to 77 was superior to that of comparative examples 1 to 6, which means that the hot melt adhesives provided in the present application had excellent adhesive properties, high cutting yield, and good electrolyte resistance.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the embodiments, and are intended to be included within the scope of the claims and description. In particular, the technical features mentioned in the respective embodiments may be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions falling within the scope of the claims.

Claims

1. A hot melt adhesive comprising: 50 to 100 parts by weight of a polyolefin resin and 5 to 40 parts by weight of insulating particles;

wherein, the liquid crystal display device comprises a liquid crystal display device,

the relative molecular mass of the polyolefin resin is 30 ten thousand to 100 ten thousand.

2. The hot melt adhesive of claim 1, wherein the polyolefin resin has a relative molecular mass of 30 to 50 tens of thousands.

3. The hot melt adhesive according to claim 1 or 2, comprising: 50 to 90 parts by weight of the polyolefin resin, 10 to 30 parts by weight of the insulating particles.

4. The hot melt adhesive of claim 3, wherein the polyolefin resin has a melting point of 130 ℃ to 150 ℃.

5. The hot melt adhesive according to claim 1, wherein the insulating particles have a particle diameter D _v 50≤3μm。

6. The hot melt adhesive of claim 5, wherein the insulating particles comprise at least one of boehmite, ceramic powder, and aluminum oxide powder.

7. The hot melt adhesive of claim 1, further comprising: 1 to 10 parts by weight of light-absorbing particles.

8. The hot melt adhesive of claim 7, wherein the absorbance of the light absorbing particles is from 0.2 to 0.8.

9. The hot melt adhesive according to claim 7 or 8, wherein the light-absorbing particles have a particle diameter of 5 μm.ltoreq.D _v 50≤10μm。

10. The hot melt adhesive of claim 9, wherein the light absorbing particles comprise at least one of carbon black, graphite, graphene, and carbon nanotubes.

11. The hot melt adhesive according to claim 1 or 7, further comprising: 1 to 8 parts by weight of a viscosity modifier.

12. The hot melt adhesive of claim 11, wherein the viscosity modifier comprises at least one of microcrystalline wax, paraffin wax, polyethylene wax, and synthetic wax.

13. The hot melt adhesive of claim 11, further comprising: 0.1 to 1 part by weight of an antioxidant.

14. The hot melt adhesive of claim 13, wherein the antioxidant comprises at least one of N-phenyl- β -naphthylamine, 2, 6-di-tert-butyl-p-cresol, 3-methyl-6-tert-butylphenol, pentaerythritol tetrakis [ β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ].

15. A method of preparing a hot melt adhesive comprising: uniformly mixing 50-100 parts by weight of polyolefin resin and 5-40 parts by weight of insulating particles to obtain the hot melt adhesive, wherein the polyolefin resin has a relative molecular mass of 30-100 ten thousand.

16. The method according to claim 15, wherein the method of preparing the polyolefin resin comprises: the bulk resin and the tackifier are mixed and heated to obtain the polyolefin resin.

17. The method of claim 16, wherein at least one of the following conditions is satisfied:

comprising 10 to 50 parts by weight of the host resin;

comprises 10 to 30 parts by weight of the tackifier.

18. The method of claim 16, wherein the host resin has a relative molecular mass of 10-50 ten thousand.

19. The method of claim 18, wherein the bulk resin has a glass transition temperature of-45 ℃ to 25 ℃.

20. The method of claim 19, wherein the host resin comprises a polyolefin.

21. The method of claim 20, wherein the polyolefin comprises at least one of an alpha-olefin copolymer, an ethylene-vinyl acetate copolymer, a styrene-isoprene-styrene block copolymer, a styrene-butadiene-styrene block copolymer, a styrene-ethylene-butylene-styrene block copolymer, and an ethylene acrylic acid copolymer.

22. The method of claim 16, wherein the tackifier has a relative molecular mass of 1000 to 10000.

23. The method of claim 22, wherein the viscosity of the tackifier is 200mPa at 100 ℃ ^. S-1000mPa ^. S。

24. The method of claim 23, wherein the tackifier comprises at least one of a hydrogenated petroleum resin, a C3 petroleum resin, a C5 petroleum resin, a C9 petroleum resin, a terpene resin, an oleoresin, and dicyclopentadiene.

25. The method as recited in claim 16, further comprising: at least one of a polar modifier and an elastomer is mixed with the host resin and the tackifier and heated to obtain the polyolefin resin.

26. The method according to claim 25, comprising: 1 to 10 parts by weight of the polar modifier.

27. The method of claim 26, wherein the polar modifier comprises at least one of maleic anhydride, polyisobutylene, polybutadiene, a silane coupling agent, and a quaternary ammonium salt.

28. The method of claim 25, comprising 10 to 30 parts by weight of the elastomer.

29. The method of claim 28, wherein the elastomer has a relative molecular mass of 10-50 tens of thousands.

30. The method of claim 29, wherein the elastomer comprises: at least one of sodium 2-bromoethyl sulfonate, styrene-isoprene-styrene block copolymer, styrene-butadiene-styrene block copolymer, styrene-ethylene-butylene-styrene block copolymer, ethylene acrylic acid copolymer, styrene butadiene rubber and nitrile rubber.

31. A pole piece comprising the hot melt adhesive of any one of claims 1-14 or prepared by the method of any one of claims 15-30.

32. The pole piece of claim 31, wherein the pole piece comprises:

the pole piece body comprises a first area, a second area and a blank area, wherein the second area is arranged on one side of the first area, the blank area is arranged on one side, far away from the first area, of the second area, the first area is provided with an active material layer, the second area is provided with an insulating layer, and the insulating layer comprises the hot melt adhesive;

And the tab is arranged at one end of the blank area, which is far away from the second area.

33. The pole piece of claim 32, wherein the first region has a width H ₁ The width of the second region is H ₂ The width of the blank area is H ₃ ，H ₁ :H ₂ :H ₃ =(18-22):(0.5-1.5):(1-3)。

34. A pole piece according to claim 33, characterized by H ₁ 、H ₂ And H ₃ At least one of the following conditions is satisfied:

50mm≤H ₁ ≤300mm；

0＜H ₂ ≤15mm；

0＜H ₃ ≤30mm。

35. a pole piece according to claim 32 or 33, characterized in that the thickness of the active material layer is T ₁ The thickness of the insulating layer is T ₂ ，T ₁ :T ₂ =(1.5-3):(0.5-1.5)。

36. A pole piece as claimed in claim 35, wherein T ₁ And T ₂ At least one of the following conditions is satisfied:

0＜T ₁ ≤125μm；

0＜T ₂ ≤50μm。

37. a method of making the pole piece of any of claims 31-36, comprising:

providing a current collector, wherein the current collector comprises a current collector body and a tab, the current collector body comprises a first area, a second area and a blank area, the second area is arranged on one side of the first area, the blank area is arranged on one side of the second area far away from the first area, the tab is arranged on one end of the blank area far away from the second area, and active material slurry is applied to the first area;

And applying hot melt adhesive to the second region.

38. The method as recited in claim 37, further comprising: the current collector is dried prior to the application of the hot melt adhesive in the second zone.

39. A battery comprising a pole piece according to any one of claims 31 to 36 or a pole piece prepared by a method according to claim 37 or 38.

40. An electrical device comprising the battery of claim 39.