CN218896656U

CN218896656U - Electrode sheet, electrode assembly, lithium battery and electronic device comprising electrode sheet and electrode assembly

Info

Publication number: CN218896656U
Application number: CN202222366220.9U
Authority: CN
Inventors: 曾士哲
Original assignee: Weilai Automobile Technology Anhui Co Ltd
Current assignee: Weilai Automobile Technology Anhui Co Ltd
Priority date: 2022-09-06
Filing date: 2022-09-06
Publication date: 2023-04-21
Anticipated expiration: 2032-09-06

Abstract

The present utility model relates to an electrode tab, an electrode assembly, and a lithium battery and an electronic device including the same, which can improve energy density while reducing volume and weight, and can reduce cost.

Description

Electrode sheet, electrode assembly, lithium battery and electronic device comprising electrode sheet and electrode assembly

Technical Field

The utility model relates to the technical field of lithium battery materials, in particular to an electrode plate, an electrode assembly, a lithium battery comprising the electrode plate and an electronic device.

Background

In order to give the electric vehicle user a better mileage experience, pursuing a high energy density of lithium batteries has been an important direction of lithium battery development. On the one hand, the energy density can be improved by upgrading the positive and negative active materials, for example, the positive electrode material is upgraded from a middle nickel ternary material to a high nickel ternary material, and the negative electrode material is upgraded from graphite to a silicon-carbon negative electrode material; on the other hand, based on the fixed positive and negative electrode active materials, an increase in energy density can be achieved by reducing the weight of the inactive auxiliary materials.

The conventional lithium battery electrode is manufactured by preparing an oil-based or water-based positive electrode or negative electrode slurry, namely uniformly dispersing positive electrode or negative electrode powder, a conductive agent and a binder in an oil-based or water-based solvent, coating the slurry on an electrode current collector, drying, and rolling and machining to obtain the electrode with a positive electrode or negative electrode 'dressing layer + current collector + dressing layer' structure. The thickness of the electrode current collector cannot be too thin due to the influence of processability, the thickness of the aluminum foil of the industrial mass production at the present stage is generally 12 μm or more, and the thickness of the copper foil is generally 6 μm or more. Therefore, the inactive electrode current collector also occupies a certain weight ratio in the battery, and further improvement of the quality and energy density of the battery cell is also affected. In addition, because the traditional electrode structure of 'dressing layer + current collector + dressing layer' needs to be subjected to a rolling process, the electrode structure is limited by the ductility of the slurry coating process and the current collector, the voltage resistance of the electrode is limited, a certain cell volume is occupied, and the improvement of the energy density of the cell volume is affected.

Disclosure of Invention

The utility model provides a composite electrode plate which is characterized by comprising an active material layer, a first metal layer and a second metal layer, wherein all or part of the first metal layer is arranged in a first area of the active material layer, and the second metal layer is arranged on the surface of one side, far away from the active material layer, of the first metal layer and in a second area of the active material layer in a physical vapor deposition mode.

In one aspect of the present utility model, all or part of the first metal layer is disposed on the first region of the active material layer by thermocompression bonding.

In one aspect of the utility model, the first metal layer and the second metal layer have the same composition material selected from at least one of aluminum, copper, an aluminum-containing alloy, or a copper-containing alloy.

In one aspect of the present utility model, the thickness of the active material layer is 20 to 1000 μm, the thickness of the first metal layer is 4 to 20 μm, and the thickness of the second metal layer is 50nm to 5 μm; preferably, the thickness of the active material layer is 100-300 μm, the thickness of the first metal layer is 4-15 μm, and the thickness of the second metal layer is 50-500nm.

In one aspect of the utility model, the first region has a width of 2-20 mm; preferably, the first region has a width of 5-10mm.

In one aspect of the present utility model, the width of the first region is a distance between the first region along the longitudinal direction of the first metal layer.

In one aspect of the present utility model, when the material of the first metal layer and the second metal layer is selected from aluminum or an alloy containing aluminum, the electrode tab is a positive electrode tab.

In one aspect of the present utility model, when the material of the first metal layer and the second metal layer is selected from copper or an alloy containing copper, the electrode tab is a negative electrode tab.

The utility model also provides an electrode assembly, wherein the electrode assembly comprises a positive electrode plate, a negative electrode plate and a diaphragm, wherein the positive electrode plate is the electrode plate selected from the above and/or the negative electrode plate is the electrode plate selected from the above.

In one aspect of the present utility model, in the electrode assembly provided by the present disclosure, the positive electrode tab and the negative electrode tab have the same number of tabs.

The utility model also provides a lithium battery, wherein the lithium battery comprises the electrode pole piece or the electrode assembly.

The utility model also provides an electronic device, wherein the electronic device comprises the lithium battery.

In one aspect of the utility model, the first region and the second region constitute a surface of the active material layer adjacent to the first metal layer.

In one aspect of the present utility model, the active material layer comprises an active material, a conductive agent, and a binder.

In one aspect of the utility model, the active material layer comprises an active material and a binder.

In one aspect of the present utility model, in the first metal layer, a width of a region where the first metal layer is not compounded with the active material layer is 1 to 20mm.

In one aspect of the utility model, the first metal layer may be used in connection with a tab.

In one aspect of the present utility model, the first metal layer is flush with the surface of the active material layer after being compounded by hot pressing.

In one aspect of the utility model, the electrode sheet is prepared by the steps of:

step (1): preparing a mixed material comprising an active material;

step (2): preparing an active material layer using the mixed material;

step (3): disposing the first metal layer at a first region of the active material layer;

step (4): and arranging the second metal layer on the surface of one side of the first metal layer far away from the active material layer and the second area of the active material layer in a physical vapor deposition mode to obtain the electrode plate.

step (1): preparing a mixed material comprising an active material, a conductive agent, and a binder;

step (2): heating and calendaring the mixed material to prepare an active material layer;

In one aspect of the present utility model, in step (2) of the preparing step, the heating temperature of the heat rolling treatment is 35 to 250 ℃, for example 35 ℃, 40 ℃, 45 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃, 210 ℃, 220 ℃, 230 ℃, 240 ℃, 250 ℃, or the like.

In one aspect of the present utility model, the thickness of the active material layer may be selected from 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm or 1000 μm.

In one aspect of the present utility model, when the first metal layer is selected from aluminum or an aluminum alloy, the thickness of the first metal layer may be selected from 10 μm, 12 μm, or 15 μm; preferably 10 μm.

In one aspect of the present utility model, when the first metal layer is selected from copper or copper alloy, the thickness of the first metal layer may be selected from 4 μm, 4.5 μm, 6 μm or 8 μm; preferably 4.5 μm.

In one aspect of the utility model, the thickness of the second metal layer may be selected from 50nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm, 800nm, 850nm, 900nm, 950nm, 1 μm, 2 μm, 3 μm, 4 μm or 5 μm.

In one aspect of the utility model, the width of the first region may be selected from 2mm, 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 15mm or 20mm.

The beneficial effects are that:

(1) The electrode plate provided by the utility model can reduce the thickness of the current collector, on one hand, reduce the volume and weight, on the other hand, improve the energy density and simultaneously reduce the cost.

(2) The electrode assembly provided by the utility model has the advantages that the number of the positive electrode plates and the negative electrode plates is the same, and the number of the negative electrode plates is different from that of the positive electrode plates in the traditional battery cell, so that the negative electrode plates with the inactive weight is reduced.

Drawings

Fig. 1 shows a schematic structure of an electrode sheet of the present utility model, wherein 101 is an active material layer, 102 is a first metal layer, and 103 is a second metal layer.

Fig. 2 shows a schematic structural diagram of a battery assembly of the present utility model, in which 201 is a negative electrode active material layer, 202 is a negative electrode first metal layer, 203 is a negative electrode second metal layer, 10 is a negative electrode tab, 20 is a separator, 30 is a positive electrode tab, 301 is a positive electrode active material layer, 302 is a positive electrode first metal layer, and 303 is a positive electrode second metal layer.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present utility model more apparent, the technical solutions of the present utility model will be clearly and completely described below with reference to the embodiments, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments. The related embodiments described herein are of illustrative nature and are intended to provide a basic understanding of the utility model. The embodiments of the present utility model should not be construed as limiting the utility model.

I. Terminology:

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 this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

In this document, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," "outer," and the like indicate or relate to a position or location based on the position or location shown in the drawings, and are used merely for convenience in describing the present utility model and to simplify the description, but do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

In the description herein, unless otherwise indicated, "above", "below" includes this number.

Unless otherwise indicated, terms used in the present utility model have well-known meanings commonly understood by those skilled in the art. Unless otherwise indicated, the numerical values of the parameters set forth in the present utility model may be measured by various measurement methods commonly used in the art (e.g., may be tested according to the methods set forth in the examples of the present utility model).

The term "about" is used to describe and illustrate minor variations. When used in connection with an event or circumstance, the terms can refer to instances where the event or circumstance occurs precisely and instances where it occurs to the close approximation. For example, when used in connection with a numerical value, the term can refer to a range of variation of less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. Additionally, amounts, ratios, and other numerical values are sometimes presented herein in a range format. It is to be understood that such range format is used for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual 10 numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited.

The list of items to which the term "at least one of," "at least one of," or other similar terms are connected may mean any combination of the listed items. For example, if items a and B are listed, the phrase "at least one of a and B" means only a; only B; or A and B. In another example, if items A, B and C are listed, then the phrase "at least one of A, B and C" means only a; or only B; only C; a and B (excluding C); a and C (excluding B); b and C (excluding A); or A, B and C. Item a may comprise a single component or multiple components. Item B may comprise a single component or multiple components. Item C may comprise a single component or multiple components.

The utility model is further described below in conjunction with the detailed description. It should be understood that the detailed description is intended by way of illustration only and is not intended to limit the scope of the utility model.

And (3) a negative electrode:

in some embodiments of the utility model, the negative electrode sheet is selected from the electrode sheets provided by the utility model.

In some embodiments of the present utility model, the negative electrode tab has a structure as shown in fig. 1, and includes a negative electrode active material layer 101, a first metal layer 102, and a second metal layer 103.

In some embodiments of the present utility model, the first metal layer 102 and the second metal layer 103 have the same composition material, and the material is selected from copper or a copper-containing alloy including copper nickel alloy, copper boron alloy, copper magnesium alloy, copper titanium alloy, copper iron alloy, copper manganese alloy, copper zinc alloy, copper silver alloy, copper zinc alloy, and the like.

In some embodiments of the present utility model, the negative electrode active material layer 101 has a thickness of 20 to 1000 μm, for example, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm or 1000 μm or any range therebetween, preferably 100 to 300 μm.

In some embodiments of the utility model, in the negative electrode tab, the thickness of the first metal layer 102 is 4-8 μm, e.g., 4 μm, 4.5 μm, 6 μm, or 8 μm or any range therebetween, preferably 4.5 μm.

In some embodiments of the utility model, the thickness of the second metal layer 103 in the negative electrode sheet is 50nm-5 μm, for example 50nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm, 800nm, 850nm, 900nm, 950nm, 1 μm, 2 μm, 3 μm, 4 μm or 5 μm or any range therebetween, preferably 50-500nm.

In some embodiments of the utility model, the width of the first region is 2-20mm, for example 2mm, 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 15mm and 20mm or any range therebetween, preferably 5-10mm.

In some embodiments of the present utility model, the specific kind of the anode active material is not particularly limited, and may be selected according to the need. Specifically, the negative electrode active material is selected from natural graphite, artificial graphite, intermediate phase micro carbon spheres (MCMB for short), hard carbon, soft carbon, silicon-carbon composite, li-Sn alloy, li-Sn-O alloy, sn, snO, snO ₂ Lithiated TiO of spinel structure ₂ -Li ₄ Ti ₅ O ₁₂ One or more of Li-Al alloys. Non-limiting examples of carbon materials include crystalline carbon, amorphous carbon, and mixtures thereof. The crystalline carbon may be amorphous or platelet-shaped, spherical or fibrous natural or artificial graphite. The amorphous carbon may be soft carbon, hard carbon, mesophase pitch carbide, calcined coke, and the like.

In some embodiments of the present utility model, the anode active material layer further includes a binder and a conductive agent. In some embodiments, the binder includes, but is not limited to: polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, an ethyleneoxy-containing polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, or the like.

In some embodiments of the present utility model, the conductive agent includes, but is not limited to: carbon-based materials, metal-based materials, conductive polymers, and mixtures thereof.

In another embodiment of the utility model, the carbon-based material is selected from natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, or any combination thereof. In some embodiments, the metal-based material is selected from metal powder, metal fiber, copper, nickel, aluminum, or silver.

In some embodiments of the utility model, the conductive polymer is a polyphenylene derivative.

And (3) a positive electrode:

in some embodiments of the utility model, the positive electrode sheet is selected from the electrode sheets provided by the utility model.

In some embodiments of the present utility model, the positive electrode sheet has a structure as shown in fig. 1, and includes a positive electrode active material layer 101, a first metal layer 102, and a second metal layer 103.

In some embodiments of the present utility model, the first metal layer 102 and the second metal layer 103 have the same composition material selected from aluminum or an aluminum-containing alloy including aluminum manganese alloy, aluminum iron alloy, aluminum silicon alloy, aluminum magnesium alloy, aluminum zinc alloy, aluminum lanthanum alloy, and the like.

In some embodiments of the present utility model, the thickness of the positive electrode active material layer 101 is 20 to 1000 μm, for example, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm or 1000 μm or any range therebetween, preferably 100 to 300 μm.

In some embodiments of the utility model, in the positive electrode sheet, the thickness of the first metal layer 102 is 10-15 μm, for example 10 μm, 12 μm, or 15 μm or any range therebetween, preferably 10 μm.

In some embodiments of the utility model, in the positive electrode sheet, the thickness of the second metal layer 103 is 50nm to 5 μm, for example, 50nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm, 800nm, 850nm, 900nm, 950nm, 1 μm, 2 μm, 3 μm, 4 μm or 5 μm or any range therebetween, preferably 50 to 500nm.

In some embodiments of the present utility model, the positive electrode active material includes a compound that reversibly intercalates and deintercalates lithium ions, and may include any one or a combination of at least two of a rock salt layered structure positive electrode material, a spinel structure positive electrode material, and an olivine structure positive electrode material, but is not limited thereto.

In some embodiments of the present utility model, the positive electrode active material may include a composite oxide containing lithium and at least one element selected from cobalt, manganese, and nickel. The specific type of the positive electrode active material is not particularly limited, and may be selected according to the need. The positive electrode active material is selected from lithium cobalt oxide LiCoO ₂ At least one of (LCO), lithium nickel manganese cobalt ternary material (NCM), lithium iron phosphate and lithium manganate. These may be used alone or in combination of 2 or more.

In some embodiments of the present utility model, the positive electrode active material may have a coating layer on the surface, or may be mixed with another compound having a coating layer.

In some embodiments of the present utility model, the coating may include at least one coating element compound selected from the group consisting of an oxide of a coating element, a hydroxide of a coating element, a oxyhydroxide of a coating element, an oxycarbonate of a coating element, and a hydroxycarbonate of a coating element. The compound used for the coating may be amorphous or crystalline. The coating elements contained in the coating may include Mg, al, co, K, na, ca, si, ti, V, sn, ge, ga, B, as, zr or a mixture thereof. The coating layer may be applied by any method as long as the method does not adversely affect the performance of the positive electrode active material. For example, the method may include any coating method well known to those of ordinary skill in the art, such as spraying, dipping, and the like.

In some embodiments of the present utility model, the positive electrode active material layer further includes a binder, and optionally further includes a conductive material. The binder enhances the bonding of the positive electrode active material particles to each other, and also enhances the bonding of the positive electrode active material to the current collector.

In some embodiments of the present utility model, non-limiting examples of binders include polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethyleneoxy-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene 1, 1-difluoroethylene, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy, nylon, and the like.

In some embodiments of the utility model, the positive electrode active material layer includes a conductive material, thereby imparting conductivity to the electrode. The conductive material may include any conductive material as long as it does not cause a chemical change. Non-limiting examples of conductive materials include carbon-based materials (e.g., natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fibers, etc.), metal-based materials (e.g., metal powders, metal fibers, etc., including, for example, copper, nickel, aluminum, silver, etc.), conductive polymers (e.g., polyphenylene derivatives), and mixtures thereof.

A diaphragm:

in some embodiments of the present utility model, the electrochemical device of the present utility model is provided with a separator between the positive electrode and the negative electrode to prevent short circuit. The material and shape of the separator used in the electrochemical device of the present utility model are not particularly limited, and may be any of the techniques disclosed in the prior art.

In some embodiments of the utility model, the separator comprises a polymer or inorganic, etc., formed from a material that is stable to the electrolyte of the present application.

In some embodiments of the utility model, the separator may include a substrate layer and a surface treatment layer. The substrate layer is a non-woven fabric, a film or a composite film with a porous structure, and the material of the substrate layer is at least one selected from polyethylene, polypropylene, polyethylene terephthalate and polyimide.

Specifically, a polypropylene porous membrane, a polyethylene porous membrane, a polypropylene nonwoven fabric, a polyethylene nonwoven fabric or a polypropylene-polyethylene-polypropylene porous composite membrane can be selected.

Electrolyte solution:

the utility model also relates to an electrolyte, in some embodiments, the electrolyte includes a lithium salt and a solvent.

In some embodiments, the lithium salt includes at least one of an organic lithium salt or an inorganic lithium salt. In some embodiments, the lithium salt includes, but is not limited to: lithium hexafluorophosphate (LiPF) ₆ ) Lithium tetrafluoroborate (LiBF) ₄ ) Lithium difluorophosphate (LiPO) ₂ F ₂ ) Lithium bis (trifluoromethanesulfonyl) imide LiN (CF) ₃ SO ₂ ) ₂ (LiTFSI), lithium bis (fluorosulfonyl) imide Li (N (SO) ₂ F) ₂ ) (LiLSI), lithium bisoxalato borate LiB (C) ₂ O ₄ ) ₂ (LiBOB) or lithium difluorooxalato borate LiBF ₂ (C ₂ O ₄ ) (LiDFOB). In some embodiments, the concentration of lithium salt in the electrolyte is: about 0.5mol/L to 3mol/L, about 0.5mol/L to 2mol/L, or about 0.8mol/L to 1.5mol/L.

In some embodiments, the solvent may be selected from 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).

Electrode assembly:

the utility model provides an electrode assembly, the structure of which is shown in fig. 2, wherein 201 is a negative electrode active material layer, 202 is a negative electrode first metal layer, 203 is a negative electrode second metal layer, 10 is a negative electrode plate, 20 is a diaphragm, 30 is a positive electrode plate, 301 is a positive electrode active material layer, 302 is a positive electrode first metal layer, and 303 is a positive electrode second metal layer.

Lithium battery:

according to some embodiments of the utility model, the lithium battery may include an outer package, which may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, or the like.

The lithium battery may also be packaged in a pouch, such as a pouch-type pouch. The soft bag can be made of one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), etc.

According to some embodiments of the present utility model, the shape of the lithium battery is not particularly limited, and may be cylindrical, square, or any other shape.

In some embodiments, the utility model also provides a battery module. The battery module includes the secondary battery described above. The battery module of the utility model adopts the lithium battery, and therefore has at least the same advantages as the lithium battery. The number of lithium batteries contained in the battery module of the utility model can be multiple, and the specific number can be adjusted according to the application and the capacity of the battery module.

In some embodiments, the utility model further provides a battery pack, which comprises the battery module. The number of battery modules included in the battery pack may be adjusted according to the application and capacity of the battery pack.

The device comprises:

the utility model also provides a device comprising at least one of the lithium battery, the battery module or the battery pack.

In some embodiments, the device may be an energy storage device such as a solid state lithium battery, a liquid state lithium battery, a fuel cell, a lithium ion capacitor, or an electric double layer capacitor.

In some embodiments, the apparatus includes, but is not limited to: electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric storage systems, and the like. To meet the high power and high energy density requirements of the device for lithium ion batteries, a battery pack or battery module may be employed.

In other embodiments, the device may be a cell phone, tablet, notebook, or the like. The device is generally required to be light and thin, and a lithium battery can be used as a power supply.

The utility model is further illustrated by the following examples. It is to be understood that these examples are illustrative of the present utility model and are not intended to limit the scope of the present utility model.

II, examples and comparative examples

Example 1:

example 1 provides a lithium battery and a method of preparing the same;

wherein, the preparation of the positive plate comprises the following steps:

(1) 98wt% of a positive electrode active ternary material (LiNi _0.83 Co _0.05 Mn _0.12 O ₂ ) And 2wt% of PTFE are put into a stirrer to be stirred at 8000rpm for 10min, so as to obtain a mixed material A;

(2) Carrying out hot pressing treatment on the mixed material A obtained in the step (1), wherein the hot pressing temperature is 35-250 ℃, the hot pressing pressure is 500kPa, and the mixed material A is hot pressed for multiple times until the thickness is 150 mu m, so as to obtain a positive electrode active material layer;

(3) In the final hot pressing step of the step (2), directly compounding one side and one end of the positive electrode active material layer with 10 mu m aluminum foil, wherein the width of the first area is 10mm, and adhering the positive electrode active material layer on the aluminum foil by utilizing the adhesive property of the polymer to obtain a positive electrode composite;

(4) And growing a 50nm ultrathin aluminum layer on one side of the positive electrode composite body by a Physical Vapor Deposition (PVD) method to realize full-pole-piece electronic conduction and obtain a positive electrode piece, wherein the structure of the positive electrode piece is shown in fig. 1 and comprises a positive electrode material layer 101, a first metal layer 102 and a second metal layer 103.

The preparation of the negative electrode plate comprises the following steps:

(1) Weighing 98wt% of negative electrode active graphite material and 2wt% of polytetrafluoroethylene PTFE, putting into a stirrer, stirring at 6000rpm for 10min to obtain a mixed material B;

(2) Carrying out hot pressing treatment on the mixture obtained in the step (1), wherein the hot pressing temperature is 35-250 ℃, the hot pressing pressure is 400kPa, and the mixture is hot pressed for multiple times until the thickness is 90 mu m, so as to obtain a positive electrode active material layer;

(3) In the final hot pressing step of the step (2), directly compounding one side and one end of the anode active material layer with 4.5 mu m copper foil, wherein the width of the first area is 10mm, and adhering the anode material layer on the copper foil by utilizing the adhesive property of the polymer to obtain an anode composite;

(4) And growing a 50nm ultrathin copper layer on one side of the negative electrode composite body by a Physical Vapor Deposition (PVD) method to realize full-electrode-plate electronic conduction and obtain a negative electrode plate, wherein the structure of the negative electrode plate is shown in figure 1 and comprises a negative electrode material layer 101, a first metal layer 102 and a second metal layer 103.

In the embodiment 1, an electrode assembly is formed by laminating a positive electrode plate, a negative electrode plate and a PP/PE composite diaphragm, wherein the structure of the electrode assembly is shown in fig. 2, 201 is a negative electrode active material layer, 202 is a negative electrode first metal layer, 203 is a negative electrode second metal layer, 10 is a negative electrode plate, 20 is a diaphragm, 30 is a positive electrode plate, 301 is a positive electrode active material layer, 302 is a positive electrode first metal layer, and 303 is a positive electrode second metal layer; wherein the number of the positive pole pieces and the negative pole pieces is 20: and 20, welding an outer tab of the electrode assembly, packaging by using an aluminum plastic film, injecting liquid, forming and separating to obtain the lithium battery.

Comparative example 1:

comparative example 1 provides a conventional lithium battery and a method of preparing the same; wherein, the preparation of the positive plate comprises the following steps:

(1) Positive electrode active ternary material (LiNi _0.83 Co _0.05 Mn _0.12 O ₂ ) Conductive agent SP, conductive agent multiwall carbon tube and PVDF, through mass ratio 96.5:1.5:0.5:1.5, feeding, and stirring by a double planetary stirrer to obtain positive electrode slurry;

(2) Coating the positive electrode coating coil on an aluminum foil with the thickness of 12 mu m, and baking to obtain a positive electrode coating coil;

(3) Rolling, slitting and die cutting to obtain a positive plate;

the preparation of the negative electrode plate comprises the following steps:

(1) Negative active graphite material and conductive agent SP, CMC, SBR, wherein the mass ratio is 95.0:1.0:1.5:2.5, stirring by a double-planetary stirrer to obtain negative electrode slurry;

(2) Coating to 4.5 micrometers copper foil, and baking to obtain a negative electrode coating electrode roll;

(3) Rolling, slitting and die cutting to obtain a negative electrode plate;

and laminating the positive pole piece, the negative pole piece and the PP/PE composite diaphragm to form an electrode assembly, wherein the number of the positive pole pieces and the negative pole pieces is 20: and 21, welding an outer tab of the electrode assembly, packaging by using an aluminum plastic film, injecting liquid, forming and separating to obtain the lithium battery.

Example 1 and comparative example 1 subjected to electrochemical performance test are shown in table 1:

contrast parameter	Comparative example 1	Example 1
			Positive plate weight (g)	9.91	8.87
Negative plate weight (g)	6.34	5.21
			Positive plate dressing weight (g)	8.70	8.70
Negative plate dressing weight (g)	4.83	4.83
			Weight of positive current collector (g)	1.20	0.16
Negative current collector weight (g)	1.52	0.39
			Outer tab weight (g)	10.88	10.88
Diaphragm weight (g)	17.12	17.12
			Weight of aluminium plastic film (g)	19.19	19.19
Electrolyte weight (g)	59.50	59.50
			Battery core weight (g)	437.99	388.34
Capacity (Ah)	35	35
			Energy Density (Wh/kg)	281	317

The above is the comparative data of example 1 and comparative example 1, the weight of the battery cell can be reduced by reducing the weight of the positive electrode current collector and the negative electrode current collector on the premise that the weight of the auxiliary materials of the positive electrode sheet and the negative electrode sheet is unchanged, the capacity calibration average value of the battery cell is 35Ah, and compared with comparative example 1, the energy density of example 1 can be improved from 281Wh/kg to 317Wh/kg; the full-charge thickness of the battery cell can be reduced from 5.23mm to 4.78mm, so that the product obtained by the utility model can realize the improvement of energy density under the condition of weight reduction.

Although illustrative embodiments have been shown and described, it will be understood by those skilled in the art that the foregoing embodiments are not to be construed as limiting the utility model, and that changes, substitutions and alterations may be made herein without departing from the spirit, principles and scope of the utility model.

Claims

1. The composite electrode pole piece is characterized by comprising an active material layer, a first metal layer and a second metal layer, wherein all or part of the first metal layer is arranged in a first area of the active material layer, and the second metal layer is arranged on the surface of one side, far away from the active material layer, of the first metal layer and in a second area of the active material layer in a physical vapor deposition mode.

2. The electrode tab of claim 1, wherein all or part of the first metal layer is disposed on the first region of the active material layer by thermal compression compounding.

3. The electrode pad of claim 1, wherein the first and second metal layers have the same composition material selected from aluminum, copper, an aluminum-containing alloy, or a copper-containing alloy.

4. The electrode tab of claim 1, wherein the active material layer has a thickness of 20-1000 μm, the first metal layer has a thickness of 4-20 μm, and the second metal layer has a thickness of 50nm-5 μm.

5. The electrode pad of claim 1, wherein the first region has a width of 2-20 mm.

6. The electrode tab of claim 1, wherein the electrode tab is a positive electrode tab when the material of the first and second metal layers is selected from aluminum or an aluminum-containing alloy.

7. The electrode tab of claim 1, wherein the electrode tab is a negative electrode tab when the material of the first and second metal layers is selected from copper or copper-containing alloys.

8. An electrode assembly, wherein the electrode assembly comprises a positive electrode sheet, a negative electrode sheet and a separator, the positive electrode sheet being selected from the electrode sheet of claim 6 and/or the negative electrode sheet being selected from the electrode sheet of claim 7;

in the electrode assembly, the positive electrode tab and the negative electrode tab have the same number of tabs.

9. A lithium battery, wherein the lithium battery comprises the electrode sheet of any one of claims 1-7 or the electrode assembly of claim 8.

10. An electronic device, wherein the electronic device comprises the lithium battery of claim 9.