A fully plastic current collector, a preparation method thereof, a pole piece and a lithium-ion battery

Abstract

The present invention belongs to the technical field of lithium battery materials, and specifically relates to an all-plastic current collector, a preparation method thereof, a pole piece and a lithium-ion battery. The present invention provides an all-plastic current collector, comprising a base film, and a doped conductive polymer layer arranged outward from one side or both sides of the base film; the conductive polymer in the doped conductive polymer layer comprises polyacetylene, polythiophene and its derivatives, polypyrrole and its derivatives, polyparaphenylene and its derivatives, polyaniline and its derivatives; the molar percentage of the dopant in the doped conjugated polymer is 5-50%. The all-plastic current collector provided by the present invention has similar thermal conductivity and electrical conductivity to traditional current collectors, and has higher corrosion resistance than traditional current collectors. The all-plastic current collector composed of the base film and the doped conductive polymer layer is very light in weight, which can greatly reduce the weight of a single cell, thereby greatly improving the energy density of the battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium battery materials, and in particular relates to an all-plastic current collector and a preparation method thereof, a pole piece and a lithium ion battery. Background Art

[0002] Energy density is one of the key technical indicators of batteries. High energy density means that battery cars can run farther and cruise longer. In order to improve the energy density of batteries, the following aspects are generally taken into consideration: 1) Increasing the gram capacity of active materials. The actual capacity of the commonly used positive electrode materials, lithium iron phosphate and low-nickel ternary materials, is less than 150mAh / g, and the capacity of the materials has basically reached the limit of existing technology; 2) Reducing the weight of single cells. Batteries include shells, electrolytes, positive and negative electrodes, current collectors and separators. The weight reduction of single cells mainly involves reducing the injection coefficient and using thinner current collectors. The current collector accounts for a large part of the weight of the battery. Reducing the weight of the current collector has a very good effect on improving the energy density of the battery; 3) Optimizing the PACK package. The integrated modules developed by major companies have greatly improved the energy density of the module, but excessive weight reduction will bring various safety hazards to the car.

[0003] Chinese patent CN108682788A discloses a flexible lithium battery, which discloses that the current collector used in the flexible lithium battery is a flexible conductive current collector. The current collector includes a plastic film, a metal coating coated on the surface of the plastic film, and a conductive coating coated on the surface of the metal coating. The thickness of the plastic film is 2-10 μm, the thickness of the metal coating is 0.5-3 μm, and the thickness of the conductive coating is 0.2-2 μm. The metal coating is one or two of aluminum, copper, and nickel.

[0004] While the patent reduces the overall thickness of the current collector, it fails to consider the battery's processability. Actual experiments have shown that metal-coated current collectors have poor mechanical strength and are easily scratched during the electrode coating and die-cutting process, leading to breakage. The thinning of the metal coating leads to significant material shedding during battery cycling, resulting in poor cycling performance. Summary of the Invention

[0005] In response to the above-mentioned technical defects, one of the objects of the present invention is to provide an all-plastic current collector, a second object of the present invention is to provide a method for preparing the all-plastic current collector, a third object of the present invention is to provide a pole piece prepared from the all-plastic current collector, and a third object of the present invention is to provide a lithium-ion battery prepared from the pole piece.

[0006] In a first aspect, the present invention provides an all-plastic current collector comprising a base film and a doped conductive polymer layer disposed outwardly from one or both sides of the base film;

[0007] The conductive polymer in the doped conductive polymer layer includes one or more of polyacetylene, polythiophene and its derivatives, polypyrrole and its derivatives, polyparaphenylene and its derivatives, polyaniline and its derivatives;

[0008] The dopant in the doped conductive polymer layer includes I2, AsF5, FeCl3, SnCl4, Na + , SO4 2- , BF 4- One or more of;

[0009] The molar percentage of the dopant in the doped conductive polymer is 5-50%, preferably 10-30%.

[0010] The conductive polymer used in this invention is lightweight, has excellent conductivity, and does not consume lithium. Other conductive agents used in lithium batteries, such as inorganic conductive agents like conductive carbon black, are not only heavy but cannot be directly applied to surfaces, consuming lithium. Therefore, inorganic conductive agents cannot be used to prepare the current collectors of this invention.

[0011] In the above-mentioned all-plastic current collector, as a preferred embodiment, the thickness of the base film is 1-300 μm (for example: 30 μm, 60 μm, 90 μm, 120 μm, 150 μm, 180 μm, 210 μm, 240 μm, 270 μm); preferably 5-20 μm (for example: 10 μm, 15 μm);

[0012] The thickness of the doped conductive polymer layer is 0.1-200 μm (eg, 10 μm, 30 μm, 60 μm, 90 μm, 120 μm, 150 μm, 180 μm, 210 μm, 240 μm, 270 μm), preferably 3-20 μm (eg, 9 μm, 12 μm, 15 μm, 18 μm).

[0013] In the above-mentioned all-plastic current collector, as a preferred embodiment, the all-plastic current collector comprises a base film, and a functional coating, a phase change material layer and a doped conductive polymer layer sequentially arranged outward from one side or both sides of the base film;

[0014] Alternatively, the all-plastic current collector comprises a base film, and a functional coating and a doped conductive polymer layer sequentially disposed outwardly from one side or both sides of the base film;

[0015] Alternatively, the all-plastic current collector includes a base film, and a phase change material layer and a doped conductive polymer layer sequentially arranged outward from one side or both sides of the base film.

[0016] In the above-mentioned all-plastic current collector, as a preferred embodiment, the thickness of the functional coating is 0-100 μm (for example: 10 μm, 30 μm, 50 μm, 70 μm, 90 μm); preferably 0.5-5 μm (for example: 1 μm, 3 μm);

[0017] The thickness of the phase change material layer is 0-200 μm (for example, 10 μm, 30 μm, 60 μm, 90 μm, 120 μm, 150 μm, 180 μm, 210 μm, 240 μm, 270 μm), preferably 2-10 μm (5 μm, 6 μm, 7 μm, 8 μm, 9 μm).

[0018] In the above-mentioned all-plastic current collector, as a preferred embodiment, the material of the base film includes one of polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polyethylene oxide (PEO), polyamide (PA), polyimide (PI) and polystyrene (PS);

[0019] The functional coating includes one of a high-temperature resistant coating, a fire-resistant coating, and a low-temperature resistant coating.

[0020] Functional coatings can not only be selected from high-temperature resistant coatings, fire-resistant coatings, and low-temperature resistant coatings, but also coatings formed from various functional materials that help improve battery performance.

[0021] In the above-mentioned all-plastic current collector, as a preferred embodiment, the phase change material in the phase change material layer includes one of an inorganic phase change material, an organic phase change material and a composite phase change material; preferably a solid-solid phase change material;

[0022] The phase change temperature of the phase change material is T m =50-120°C (for example: 60°C, 70°C, 80°C, 100°C, 110°C).

[0023] The inorganic phase change material includes inorganic phase change materials such as crystal water, salt, and molten salt; the organic phase change material includes paraffin and acetic acid organic phase change materials; the solid-solid phase change material includes one or more of inorganic salts, polyols, and polymer phase change materials.

[0024] Furthermore, the inorganic salt includes perovskite (for example: (nC x H 2x+1 NH3)MY4, wherein M=Mn, Cu, Fe, Co, Zn, etc.; Y is a halogen, such as Cl, etc.; x is between 8-18) and / or ammonium thiocyanate (NH4SCN); the polyol includes one or more of pentaerythritol, neopentyl glycol, tris(hydroxymethyl)aminomethane, trimethylolpropane, etc.; the polymer phase change material includes polyethylene and / or polyethylene glycol, etc.

[0025] In the present invention, the main function of the phase change material layer is to absorb the heat generated by the battery during the charge and discharge cycle. In particular, when the temperature inside the battery rises sharply, the phase change material can absorb and store this part of the heat, and gradually release this part of the heat when the battery temperature drops.

[0026] In a second aspect, the present invention further provides a method for preparing the above-mentioned all-plastic current collector, comprising the following steps:

[0027] S1: applying a functional coating on at least one side of the base film to obtain a functional base film;

[0028] S2: coating a phase change material on the surface of the functional base film;

[0029] S3: coating the doped conductive polymer solution on the surface of the phase change material;

[0030] S4: The coated current collector is roller-pressed to obtain a fully plastic current collector.

[0031] In the above preparation method, as a preferred embodiment, the solvent of the doped conductive polymer solution includes one or more of acetonitrile and NMP;

[0032] The solid content of the doped conductive polymer solution is 70-95% (eg, 75%, 80%, 90%).

[0033] In the above preparation method, as a preferred embodiment, the coating method includes gravure coating, micro gravure coating, extrusion coating, blade coating or spray coating;

[0034] The surface density of the all-plastic current collector is 5-54 g / cm 2 ;

[0035] The compaction ratio of the roller pressing is 1-3 (for example: 1.5, 1.7, 1.9, 2.1, 2.5, 2.7, 2.9) (ie, thickness before rolling / thickness after rolling = 1-3).

[0036] In the present invention, the current collector of the present invention has greater deformation and elongation than traditional current collectors. The current collector is directly coated with active materials without rolling, which has a greater impact on the subsequent rolling thickness of the active material and affects the accuracy of its actual compaction. Therefore, the all-plastic current collector used to coat the negative electrode material is preferably compacted to 1.45-1.7, and the all-plastic current collector used to coat the positive electrode material is preferably compacted to 2.3-2.65.

[0037] In the present invention, the surface density of the all-plastic current collector is 5-54 g / cm 2 The traditional copper foil surface density is 54g / cm 2, the surface density of aluminum foil is 33g / cm 2 The surface density of the all-plastic current collector can reach the surface density of traditional copper foil and aluminum foil. The present invention can even prepare a current collector with a lower surface density.

[0038] In a third aspect, the present invention further provides a pole piece, comprising the above-mentioned current collector, active material, conductive agent, and binder;

[0039] In the above-mentioned electrode sheet, the active material includes one of a positive electrode active material and a negative electrode active material.

[0040] In the present invention, the positive electrode active material, the negative electrode active material, the conductive agent, and the binder are not particularly limited, and commonly used materials in the art can be used, which will not be described in detail here.

[0041] In a fourth aspect, the present invention further provides a lithium-ion battery, comprising a positive electrode sheet using the above-mentioned electrode sheet as a positive electrode, a negative electrode sheet using the above-mentioned electrode sheet as a negative electrode, a separator, an electrolyte, and a casing.

[0042] In the present invention, the electrolyte, the diaphragm, and the housing are not particularly limited, and are all conventional technologies in the art, and will not be described in detail here.

[0043] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0044] 1. The present invention provides a fully plastic current collector, comprising a base film, and a doped conductive polymer layer disposed outwardly from one or both sides of the base film; the conductive polymer in the doped conductive polymer layer comprises polyacetylene, polythiophene and its derivatives, polypyrrole and its derivatives, polyparaphenylene and its derivatives, polyaniline and its derivatives; the dopant in the doped conductive polymer layer comprises I2, AsF5, FeCl3, SnCl4, Na + , SO4 2- , BF 4- One or more of the dopant; the molar percentage of the dopant in the doped conjugated polymer is 5-50%. The all-plastic current collector provided by the present invention has thermal and electrical conductivity comparable to traditional current collectors (e.g., copper foil and aluminum foil), and exhibits superior corrosion resistance. The all-plastic current collector, consisting of the base film and the doped conductive polymer layer, is extremely lightweight, significantly reducing the weight of a single cell, thereby significantly increasing the energy density of the battery.

[0045] 2. The all-plastic current collector provided by the present invention can be adaptively coated with a functional coating as needed, making it not only conductive and corrosion-resistant like traditional current collectors, but also possessing various functions added by the functional coating. Traditional current collectors do not have this functionality.

[0046] 3. This invention incorporates a unique phase-change material (PCM) into the current collector. PCM is a heat storage material that absorbs heat when the external temperature reaches its melting point. When the external temperature drops, the absorbed heat is gradually released. The PCM's inclusion in the current collector allows for very precise control of the electrode surface temperature. This is especially true when the battery experiences rapid temperature increases, as the PCM absorbs heat and acts as a buffer, significantly improving battery safety.

[0047] 4. Traditional current collectors can easily cause local overheating of the current collector during rapid charging and discharging of the battery. The thermal conductivity of the all-plastic current collector is not as good as that of the metal current collector, and it will not cause heat collection due to excessive current.

[0048] 5. The all-plastic current collector has an advantage in weight. Its weight is much lower than that of the current collector, which can greatly reduce the weight of the single battery cell.

[0049] 6. Metal is easily damaged when folded and has low plasticity. It cannot withstand continuous folding and is easily deformed when rubbed. The fully plastic current collector is fully plastic and not easily deformed. It is resistant to stretching and folding, and its mechanical properties are better than those of metal current collectors. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a schematic diagram of the structure of the all-plastic current collector according to Example 1 of the present invention;

[0051] Figure 2 This is a temperature change curve diagram of a battery assembled with current collectors from Examples 1, 5, 7 and Comparative Example 1 in Test Example 2 and subjected to a 100% SOC charge and discharge test.

[0052] Reference numerals: 1 - doped conductive polymer layer; 2 - phase change material layer; 3 - functional coating layer; 4 - base film. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention.

[0054] The embodiments of the present invention are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and processes are given. However, the protection scope of the present invention is not limited to the following embodiments. The process parameters in the following embodiments that do not specify specific conditions are generally based on conventional conditions.

[0055] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to form one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in the present invention.

[0056] In the present invention, unless otherwise specified and / or explained, all numerical values involving the amounts of components are "parts by weight or weight percentages" from beginning to end. The process parameters in the following examples where specific conditions are not specified are generally based on conventional conditions.

[0057] Example 1

[0058] This embodiment provides a method for preparing a fully plastic current collector, comprising the following steps:

[0059] S1: Select a base film with a thickness of 4 μm, made of polypropylene, and spray a 2 μm high-temperature resistant coating (the material of the high-temperature resistant coating is silicon nitride) on both sides of the base film;

[0060] S2: Paraffin wax and polyethylene are melted in a mass ratio of 7:3 and stirred evenly. The mixture is coated on the surface of the high-temperature resistant coating by gravure coating. The thickness of the single-sided phase change material layer is 2 μm. The phase change temperature T is obtained. m =100°C phase change material layer;

[0061] S3: According to the solid content of 85%, the doped polyacetylene conductive polymer (the dopant is iodine, and the molar percentage of the dopant in the doped conductive polymer is 30%) is dissolved in acetonitrile solution and coated on the surface of the phase change material layer by micro-gravure coating. The thickness of the single-sided doped conductive polymer is 4 μm.

[0062] S4: The coated current collector is rolled by a cold roller with a compaction of 2.2 and a temperature of -2°C to obtain a surface density of 20 g / cm 2 All-plastic current collector.

[0063] The schematic diagram of the all-plastic current collector structure prepared in this embodiment is shown in FIG. Figure 1 As shown, the base film 4 is coated with a functional coating 3, a phase change material layer 2 and a doped conductive polymer layer 1 in sequence.

[0064] Example 2

[0065] This embodiment provides a method for preparing a fully plastic current collector, comprising the following steps:

[0066] S1: Select a base film with a thickness of 3 μm, made of polyethylene, and spray a 2 μm high-temperature resistant coating (the material of the high-temperature resistant coating is silicon nitride) on both sides of the base film;

[0067] S2: Paraffin wax and polyethylene are melted in a mass ratio of 8:2 and stirred evenly. The mixture is coated on the surface of the high-temperature resistant coating by gravure coating. The thickness of the single-sided phase change material layer is 3 μm. The phase change temperature T is obtained. m =90°C phase change material layer;

[0068] S3: According to the solid content of 85%, the doped polyacetylene conductive polymer (the dopant is iodine, and the molar percentage of the dopant in the doped conductive polymer is 20%) is dissolved in acetonitrile solution and coated on the surface of the phase change material layer by micro-gravure coating. The thickness of the single-sided doped conductive polymer is 5 μm.

[0069] S4: The coated current collector is rolled by a cold roller with a compaction of 1.3 and a temperature of -2°C to obtain a surface density of 30 g / cm 2 All-plastic current collector.

[0070] Example 3

[0071] This embodiment provides a method for preparing a fully plastic current collector, comprising the following steps:

[0072] The difference between this embodiment and embodiment 1 is that the thickness of the high temperature resistant coating and the phase change material layer is 0 μm. The remaining steps are the same as those in embodiment 1.

[0073] Example 4

[0074] This embodiment provides a method for preparing a fully plastic current collector, comprising the following steps:

[0075] The difference between this embodiment and embodiment 1 is that the thickness of the high temperature resistant coating is 0 μm. The remaining steps are the same as those in embodiment 1.

[0076] Example 5

[0077] This embodiment provides a method for preparing a fully plastic current collector, comprising the following steps:

[0078] The difference between this embodiment and embodiment 1 is that the thickness of the phase change material layer is 0 μm. The remaining steps are the same as those in embodiment 1.

[0079] Example 6

[0080] This embodiment provides a method for preparing a fully plastic current collector, comprising the following steps:

[0081] The difference between this embodiment and embodiment 1 is that the thickness of the single-sided high-temperature resistant coating is 4 μm. The remaining steps are the same as those in embodiment 1.

[0082] Example 7

[0083] This embodiment provides a method for preparing a fully plastic current collector, comprising the following steps:

[0084] The difference between this embodiment and embodiment 1 is that the thickness of the single-sided phase change material layer is 4 μm. The remaining steps are the same as those in embodiment 1.

[0085] Example 8

[0086] This embodiment provides a method for preparing a fully plastic current collector, comprising the following steps:

[0087] The difference between this embodiment and embodiment 1 is that the thickness of the single-sided doped conductive polymer layer is 6 μm. The remaining steps are the same as those in embodiment 1.

[0088] Example 9

[0089] This embodiment provides a method for preparing a fully plastic current collector, comprising the following steps:

[0090] The difference between this embodiment and embodiment 1 is that the thickness of the single-sided doped conductive polymer layer is 1 μm. The remaining steps are the same as those in embodiment 1.

[0091] Example 10

[0092] This embodiment provides a method for preparing a fully plastic current collector, comprising the following steps:

[0093] The difference between this embodiment and embodiment 1 is that the compaction of the cold pressing roller is 1.8. The remaining steps are the same as those in embodiment 1.

[0094] Example 11

[0095] This embodiment provides a method for preparing a fully plastic current collector, comprising the following steps:

[0096] The difference between this embodiment and embodiment 1 is that the compaction of the cold pressing roller is 1. The remaining steps are the same as those in embodiment 1.

[0097] Comparative Example 1

[0098] The current collector in this comparative example is a 6 μm copper foil commonly used in the market.

[0099] Test Example 1

[0100] The current collectors of Examples 1-11 and Comparative Example 1 were subjected to performance tests, and the test indicators included high temperature resistance and electrical conductivity.

[0101] The test method for high temperature resistance is as follows: the current collector is placed in a forced air drying oven, the oven temperature is raised from 40°C at a rate of 1°C / min, and the temperature and deformation state at which the current collector begins to deform are recorded.

[0102] The test method for the electrical conductivity is as follows: referring to "JIS H0505-1975 Resistivity and conductivity measurement methods of non-ferrous metal materials", the electrical conductivity (% IACS) at 25°C is measured by a four-terminal method.

[0103] The specific test results are shown in Table 1

[0104] Table 1

[0105]

[0106]

[0107] It can be seen from Table 1 that traditional copper foil begins to change color at around 180°C, and the copper on the surface is oxidized and loses its conductivity. The all-plastic current collector without a high-temperature resistant layer can also withstand a high temperature of 180°C. The all-plastic current collector coated with a high-temperature resistant layer can withstand an increase in deformation temperature as the coating thickness increases.

[0108] The conductivity of doped conductive polymers is comparable to that of copper foil. Even if the thickness of the conductive polymer is only 1μm, it can still conduct electricity. However, if the conductive polymer layer is too thick, the internal resistance of the current collector will increase, and the corresponding conductivity will also decrease.

[0109] Test Example 2

[0110] The current collectors of Examples 1, 5, 7 and Comparative Example 1 were assembled into batteries and placed in an insulated box for 100% SOC charge and discharge experiments. The temperature change curve was recorded, as shown in FIG. Figure 2 As shown. Figure 2 It can be seen that the presence of the phase change material layer can absorb the heat generated by the battery during the charging and discharging process. The thickness of the phase change material layer is closely related to the absorbed heat. The thicker the phase change material layer, the more heat it absorbs, and the more the battery temperature drops.

[0111] Test Example 3

[0112] The positive electrode active material was coated on the current collectors of Examples 1, 10, 11 and Comparative Example 1 (the active material layer composition was the same in each Example and Comparative Example, the slurry solid content was the same, and the coating thickness before compaction was the same). The thickness change of the active material layer under the same electrode compaction was recorded. The surface density of the electrode was 400 g / cm 2 .

[0113] The specific test results are shown in Table 2:

[0114] Table 2

[0115]

[0116] It can be seen from Table 2 that when the compaction of the all-plastic current collector is close to or exceeds the compaction of the active material layer, the thickness of the active material layer is consistent with the compaction thickness of the copper current collector. When the all-plastic current collector is rolled directly with the active material layer without cold pressing, the rolling thickness of the active material is larger, indicating that the compaction of the active material layer is smaller.

[0117] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are within the scope of protection of the pending claims of the present invention.

Claims

1. A fully plastic current collector, characterized in that: It comprises a base film, and a functional coating, a phase change material layer and a doped conductive polymer layer sequentially arranged outward from one side or both sides of the base film; The conductive polymer in the doped conductive polymer layer includes one or more of polyacetylene, polythiophene and its derivatives, polypyrrole and its derivatives, polyparaphenylene and its derivatives; The dopant in the doped conductive polymer layer includes I2, AsF5, SnCl4, Na + , SO4 2- , BF 4- One or more of; The molar percentage of the dopant in the doped conductive polymer is 5-50%; The thickness of the base film is 1-300 μm; The thickness of the doped conductive polymer layer is 0.1-200 μm; The functional coating includes one of a high-temperature resistant coating, a fire-resistant coating, and a low-temperature resistant coating.

2. The all-plastic current collector according to claim 1, characterized in that: The thickness of the base film is 5-20 μm; the thickness of the doped conductive polymer layer is 3-20 μm.

3. The all-plastic current collector according to claim 1, characterized in that: The thickness of the functional coating is 0.5-100 μm; The thickness of the phase change material layer is 2-200 μm.

4. The all-plastic current collector according to claim 3, characterized in that: The thickness of the functional coating is 0.5-5 μm; The thickness of the phase change material layer is 2-10 μm.

5. The all-plastic current collector according to claim 3, characterized in that: The material of the base film includes one of polypropylene, polyethylene, polyethylene terephthalate, polyethylene oxide, polyamide, polyimide and polystyrene; And / or, the phase change material in the phase change material layer includes one of an inorganic phase change material, an organic phase change material and a composite phase change material; the phase change temperature of the phase change material is T m =50-120℃.

6. A method for preparing the all-plastic current collector according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1: applying a functional coating on at least one side of the base film to obtain a functional base film; S2: coating a phase change material on the surface of the functional base film; S3: coating the doped conductive polymer solution on the surface of the phase change material; S4: The coated current collector is roller-pressed to obtain a fully plastic current collector.

7. The method for preparing the all-plastic current collector according to claim 6, characterized in that: The solvent of the doped conductive polymer solution includes one or more of acetonitrile and NMP; And / or, the solid content of the doped conductive polymer solution is 70-95%; and / or, the coating method includes gravure coating, micro gravure coating, extrusion coating, blade coating or spray coating; And / or, the surface density of the all-plastic current collector is 5-54 g / cm 2 ; And / or, the compaction ratio of the roller pressing is 1-3.

8. A pole piece, characterized in that: The invention comprises the all-plastic current collector according to any one of claims 1 to 5 or the all-plastic current collector obtained by the preparation method according to claim 6 or 7, an active material, a conductive agent, and a binder.

9. The pole piece according to claim 8, characterized in that: The active material includes one of a positive electrode active material and a negative electrode active material.

10. A lithium ion battery, characterized in that: The invention comprises a positive electrode sheet using the electrode sheet of claim 8 or 9 as a positive electrode, a negative electrode sheet using the electrode sheet of claim 8 or 9 as a negative electrode, a diaphragm, an electrolyte, and a shell.

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