Functional current collector

Abstract

The invention relates to the technical field of current collectors, and discloses a functional current collector. Comprising the following operation steps: S1, placing a polymer film in a 45-55 DEG C potassium hydroxide solution of a track etching treatment device, introducing radon gas, and etching for 0.5-4 hours to obtain a porous polymer layer; and S2, depositing a positive electrode conductive layer on one surface of the porous polymer layer, and depositing a negative electrode conductive layer on the other surface to obtain the functional current collector.

Description

Technical Field

[0001] The present invention relates to the technical field of current collectors, specifically functional current collectors. Background Art

[0002] At present, with the continuous penetration of electric vehicles, the market has put forward higher requirements for the endurance of electric vehicles; in order to solve the endurance problem of electric vehicles; among many solutions, bipolar batteries, as high specific energy batteries with good prospects, have continuously attracted people's attention. Among them, a bipolar battery is a battery formed by stacking bipolar electrode plates (electrode plates prepared by coating positive and negative electrode materials on both sides of a current collector) in series; due to the series conduction relying on its own current collector, the wires between electrodes in traditional batteries are omitted, thereby reducing the mass and volume of the battery, improving the energy density of the battery, and its series battery structure can increase the output voltage and power of the battery, thereby enhancing the output power of the battery; it is reported that with bipolar batteries, the number of battery cells that can be accommodated in a battery pack of the same size is also 1.4 times that of traditional batteries, and the output power of the battery is about 1.5 times that of traditional ones, showing good potential.

[0003] As an important component of bipolar batteries, the structure of the current collector has a great influence on the energy density of the battery; currently, the process of compounding aluminum foil (13μm) and copper foil (4.5μm) is usually used to prepare functional current collectors, but the functional current collectors prepared by this method are too heavy and have a high areal density, thus affecting the energy density of the battery, and due to the pinhole defects in the aluminum foil and copper foil, the prepared functional current collectors have pinhole defects, which in turn lead to problems such as poor cycle performance of the prepared batteries.

[0004] In summary, to solve the above problems, it is of great significance to prepare a functional current collector with a low areal density and no pinhole defects. Summary of the Invention

[0005] The purpose of the present invention is to provide a functional current collector to solve the problems raised in the prior art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A functional current collector, the structure of the functional current collector sequentially includes a negative electrode conductive layer, a porous polymer layer, and a positive electrode conductive layer.

[0008] Preferably, the thickness of the negative electrode conductive layer is 0.5 - 2μm; the thickness of the polymer layer is 1.0 - 10μm; the thickness of the positive electrode conductive layer is 0.5 - 2μm.

[0009] Preferably, the porosity of the porous polymer layer is 10% - 80%, and the pore diameter is 0.1 - 1μm.

[0010] In the solution, the polymer layer has a porous structure and serves as the carrier of the positive and negative electrode conductive layers. If the porosity is too low, the contact area between the positive and negative electrode conductive layers is small, and the conductivity with the polymer layer becomes poor, resulting in poor cycle performance of the battery. If the porosity is too high, the mechanical properties of the polymer layer are poor, and film breakage is likely to occur during the preparation process, leading to an increase in the defective rate. The pore diameter is 0.1 - 1 μm. If the pore diameter is too small, the positive and negative electrode conductive layers are not easily in contact, and the conductivity with the polymer layer becomes poor, resulting in poor cycle performance of the battery. If the pore diameter is too large, the conductive layer cannot completely cover the porous structure during the preparation process, and defects are likely to occur, resulting in poor cycle performance of the battery. Considering the application requirements of the functional current collector and taking into account the difficulty of the preparation process and the cost, the preferred thickness of the polymer film is 1.0 - 10 μm.

[0011] The preparation method of the functional current collector includes the following operating steps:

[0012] S1: Place the polymer film in a potassium hydroxide solution at 45 - 55 °C in a track etching treatment device, introduce radon gas, and etch for 0.5 - 4 hours to obtain a porous polymer layer;

[0013] S2: Deposit a positive electrode conductive layer on one side of the porous polymer layer and deposit a negative electrode conductive layer on the other side to obtain the functional current collector.

[0014] More preferably, the material of the polymer film includes one or more of polyethylene terephthalate (PET), polypropylene (PP), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyethylene (PE), polypropylene, polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polystyrene (PS), polyimide (PI);

[0015] The concentration of the potassium hydroxide solution is 4 - 6 mol / L; the introduction amount of the radon gas is 2500 - 3500 Bq / m3; the material of the positive electrode conductive layer includes one or more of aluminum, carbon, gold, silver and their alloys; the material of the negative electrode conductive layer includes one or more of copper, nickel, titanium, carbon, gold, silver and their alloys.

[0016] More preferably, when the negative electrode conductive layer is a copper layer, a protective layer is provided on the surface of the negative electrode conductive layer, and the thickness of the protective layer is 5 - 100 nm; the material of the protective layer includes one or more of nickel, chromium, nickel-based alloy, copper-based alloy, alumina, silica, nickel oxide, chromium oxide, cobalt oxide, graphite, carbon black, copper chromium oxide, carbon nano quantum dot, carbon nanotube, carbon nanofiber, graphene.

[0017] The method for setting the protective layer includes one of physical vapor deposition, chemical vapor deposition, in-situ forming, and coating.

[0018] In the solution, physical vapor deposition method preferably includes vacuum evaporation and magnetron sputtering; chemical vapor deposition preferably includes atmospheric pressure chemical vapor deposition and plasma enhanced chemical vapor deposition; in-situ forming preferably includes the method of in-situ forming a metal oxide passivation layer on the surface of the metal layer; coating method preferably includes die coating, blade coating, and extrusion coating.

[0019] In the solution, the negative electrode conductive layer serves as the support layer and conductive layer of the battery negative electrode material; considering cost, processability, and conductivity, the raw materials of the conductive layer A are preferably copper, nickel, carbon, and their alloys; taking into account conductivity and considering the influence of thickness on the surface density of the functional current collector, the thickness is preferably 0.5 - 2 μm. If it is too thin, the conductivity is poor; if it is too thick, the surface density of the functional current collector is high, resulting in a decrease in the energy density of the prepared battery; the negative electrode conductive layer can be prepared by physical vapor deposition methods (magnetron sputtering, evaporation). When the raw material of the negative electrode conductive layer is a metal material, electroplating, electroless plating, and their combinations can be used for preparation.

[0020] In the solution, the positive electrode conductive layer serves as the support layer and conductive layer of the battery positive electrode material; considering cost and processability, aluminum, carbon, and their alloys are preferred; taking into account conductivity and considering the influence of thickness on the surface density of the functional current collector, the thickness is preferably 0.5 - 2 μm; the positive electrode conductive layer can be prepared by physical vapor deposition methods (magnetron sputtering, evaporation).

[0021] More preferably, the deposition methods of the positive electrode conductive layer and the negative electrode conductive layer include one of magnetron sputtering and vacuum evaporation.

[0022] More preferably, the conditions for magnetron sputtering are: power is 8 - 15 kW, argon is used as the gas source, the gas flow rate is 75 - 85 mL / min, the air pressure is 0.05 - 0.08 Pa, and the main roller cooling temperature is -10 - -20 °C; the conditions for vacuum evaporation are: the melting and evaporation temperature is 1200 - 4000 °C, and the vacuum degree is 5×10-3 - 5×10-2 Pa.

[0023] Preferably, the polymer film is a modified PET film, and its preparation method is as follows: (1) Add 4,5-imidazole dicarboxylic acid and tetrafluoroterephthalic acid into N,N-dimethylformamide, and mix evenly to obtain a mixed solution; (2) Add terephthalic acid, ethylene glycol, and a catalyst, set the pressure to 0.3-0.4 MPa, the temperature to 230-250 °C, react for 20-30 minutes, dropwise add the mixed solution and ethylene glycol, finish dropping in 1-2 hours, and continue to react for 3-4 hours; raise the temperature to 270-280 °C, evacuate, reduce the vacuum degree to 50-60 Pa, stir at 20-50 W / 40 Hz for 1-2 hours, purify and dry to obtain modified polyethylene terephthalate; use it as a raw material to melt and extrude, cast into a film, and biaxially stretch to obtain a modified PET film.

[0024] Preferably, the raw materials of the mixed solution include the following components: by mass, 1-2 parts of 4,5-imidazole dicarboxylic acid, 0.2-0.3 parts of tetrafluoroterephthalic acid, and 20-30 parts of N,N-dimethylformamide; the raw materials of the modified polyethylene terephthalate include the following components: by mass, 1.7-2.7 parts of terephthalic acid, 1.5-2.3 parts of ethylene glycol, 0.5-1 part of the mixed solution, and 0.02-0.05 parts of the catalyst.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The functional current collector prepared by the present invention includes a three-layer structure of a negative conductive layer, a porous polymer layer, and a positive conductive layer; in the solution, radon gas is used to regulate the porosity and pore size of the porous polymer layer, so that the positive and negative conductive layers are well filled in the pores, realizing good contact between the conductive layer and the polymer layer, and realizing no pinhole defects; the present invention also realizes the preparation of a low areal density functional current collector by regulating the thicknesses of the polymer layer and the positive and negative conductive layers; the above can all realize the preparation of low areal density and pinhole defects, and promote the cycle performance of the functional current collector battery prepared thereby; the blend layer formed by the polymer layer and the positive and negative conductive layer materials has good corrosion resistance to the electrolyte, which can further improve the cycle performance of the battery.

[0027] In order to improve the corrosion resistance of the polymer layer; in this solution, 4,5-imidazole dicarboxylic acid and tetrafluoroterephthalic acid are further introduced to modify polyethylene terephthalate (PET); and a modified PET film is made from it as a raw material.

[0028] Among them, the imidazole heterocyclic ring on 4,5-imidazole dicarboxylic acid has a special conjugated structure and electron cloud distribution, endowing it with certain chemical stability; when incorporated into the PET segment, it can effectively improve the overall chemical stability, making the modified PET film have better corrosion resistance; moreover, the nitrogen atom in the imidazole heterocyclic ring can form a coordination bond with metal ions; when the modified PET film comes into contact with a metal material, the nitrogen atom of the imidazole heterocyclic ring can coordinate with metal ions or atoms on the metal surface, enhancing the interfacial property between the metal material and the modified PET film and promoting the interfacial adhesion of the positive and negative electrode conductive layers; thus improving the stability of the battery structure.

[0029] Among them, tetrafluoro terephthalic acid has high thermal stability and a rigid structure. Introducing it into the PET molecular chain can enhance the intermolecular force of PET, enabling the film to maintain a stable structure at high temperatures and not easily deform; and fluorine atoms have a strong electronegativity, which can form a protective layer with a relatively high electron cloud density on the surface of the PET molecule, making the modified PET film have better corrosion resistance and being able to better resist the erosion of substances such as acids, alkalis, and organic solvents in the battery electrolyte, thus extending the service life of the film.

[0030] In summary, the present invention prepares a new functional current collector, which has a low areal density, no pinhole defects, and corrosion resistance, can effectively solve the problems existing in traditional functional current collectors, and has a simple and easy preparation process and is easy to scale up the operation. Specific Embodiments

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

[0032] Example 1, Preparation method of the functional current collector;

[0033] S1: Place a 4.5 μm PET film (Yihua Toray, 4.5D08) in 50 °C potassium hydroxide (5 mol / L) in a track etching treatment device, turn on the generator, release radon gas with a concentration of 3000 Bq / m 3 and etch for 0.5 hours to obtain a porous polymer layer with a porosity of 10% and a pore diameter of 0.1 μm.

[0034] S2: Place the porous polymer layer in the chamber for vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering. Place it in a chromic acid aqueous solution of 0.6 g / L and treat it for 20 seconds to deposit a 5-nm-thick protective layer (copper-chromium oxide passivation layer), obtaining a functional current collector with a thickness of 6.505 μm;

[0035] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon is the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0036] Example 2 is based on Example 1, the difference is that the etching time is 2.5 hours and the porosity of the PET porous membrane is 50%;

[0037] S1: Place the 4.5-μm PET membrane in 50°C potassium hydroxide (5 mol / L) in the track etching treatment device, turn on the generator, release radon gas with a concentration of 3000 Bq / m 3 and etch for 2.5 hours to obtain a porous polymer layer with a porosity of 50% and a pore diameter of 0.1 μm;

[0038] S2: Place the porous polymer layer in the chamber for vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering. Place it in a chromic acid aqueous solution of 0.6 g / L and treat it for 20 seconds to deposit a 5-nm-thick protective layer (copper-chromium oxide passivation layer); obtain a functional current collector with a thickness of 6.505 μm;

[0039] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon is the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0040] Example 3 is based on Example 1, the difference is that the etching time is 4 hours and the porosity of the PET porous membrane is 80%;

[0041] S1: Place the 4.5-μm PET membrane in 50°C potassium hydroxide (5 mol / L) in the track etching treatment device, turn on the generator, release radon gas with a concentration of 3000 Bq / m3 Radon gas is used to etch for 4.0 hours to obtain a porous polymer layer with a porosity of 80% and a pore size of 0.1 μm;

[0042] S2: Place the porous polymer layer in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200 °C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber to deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a chromic acid aqueous solution of 0.6 g / L and treat it for 20 seconds to deposit a 5-nm-thick protective layer (copper chromic oxide passivation layer) to obtain a functional current collector with a thickness of 6.505 μm;

[0043] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon gas is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10 °C.

[0044] Example 4 is based on Example 1, the difference is that the radon concentration is 5000 Bq / m 3 , and the pore size of the PET porous membrane is 0.5 μm

[0045] S1: Place a 4.5-μm PET membrane in 50 °C potassium hydroxide (5 mol / L) in the track etching treatment device, turn on the generator, release radon gas with a concentration of 5000 Bq / m 3 to etch for 0.5 hour to obtain a porous polymer layer with a porosity of 10% and a pore size of 0.5 μm;

[0046] S2: Place the porous polymer layer in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200 °C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber to deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a chromic acid aqueous solution of 0.6 g / L and treat it for 20 seconds to deposit a 5-nm-thick protective layer (copper chromic oxide passivation layer) to obtain a functional current collector with a thickness of 6.505 μm;

[0047] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon gas is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10 °C.

[0048] Example 5 is based on Example 1, the difference is that the pore size of the PET porous membrane is 1.0 μm and the radon gas concentration is 8000 Bq / m3 ;

[0049] S1: Place a 4.5-μm PET film in 50°C potassium hydroxide (5 mol / L) in a track etching treatment device. Turn on the generator to release radon gas with a concentration of 8000 Bq / m 3 , and etch for 0.5 hour to obtain a porous polymer layer with a porosity of 10% and a pore diameter of 1.0 μm;

[0050] S2: Place the porous polymer layer in a vacuum evaporation chamber. Melt and evaporate high-purity aluminum wire (purity ≥ 99.99%) in a metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber to deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a 0.6 g / L chromic acid aqueous solution and treat for 20 seconds to deposit a 5-nm protective layer (copper-chromium oxide passivation layer) to obtain a functional current collector with a thickness of 6.505 μm;

[0051] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon gas is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0052] Example 6 is based on Example 1, the difference being that the thickness of the PET porous membrane is 1 μm;

[0053] S1: Place a 1-μm PET film in 50°C potassium hydroxide (5 mol / L) in a track etching treatment device. Turn on the generator to release radon gas with a concentration of 3000 Bq / m 3 , and etch for 0.5 hour to obtain a porous polymer layer with a porosity of 10% and a pore diameter of 0.1 μm;

[0054] S2: Place the porous polymer layer in a vacuum evaporation chamber. Melt and evaporate high-purity aluminum wire (purity ≥ 99.99%) in a metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber to deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a 0.6 g / L chromic acid aqueous solution and treat for 20 seconds to deposit a 5-nm protective layer (copper-chromium oxide passivation layer) to obtain a functional current collector with a thickness of 3.005 μm;

[0055] Among them, the conditions for magnetron sputtering are as follows: a copper target (purity 99.99%) is used as the target material, the target power is 10 kW, argon is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0056] Example 7 is based on Example 1, with the difference that the thickness of the PET porous membrane is 10 μm;

[0057] S1: Place the 10-μm PET membrane in 50°C potassium hydroxide (5 mol / L) in a track etching treatment device, turn on the generator, release radon gas with a concentration of 3000 Bq / m 3 to etch for 0.5 hours to obtain a porous polymer layer with a porosity of 10% and a pore diameter of 0.1 μm;

[0058] S2: Place the porous polymer layer in the chamber of vacuum evaporation. Melt and evaporate high-purity aluminum wire (purity ≥99.99%) in the metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber to deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a 0.6 g / L chromic acid aqueous solution for 20 seconds to deposit a 5-nm protective layer (copper chromate oxide passivation layer) to obtain a functional current collector with a thickness of 12.005 μm;

[0059] Among them, the conditions for magnetron sputtering are as follows: a copper target (purity 99.99%) is used as the target material, the target power is 10 kW, argon is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0060] Example 8 is based on Example 1, with the difference that the thickness of the negative conductive layer is 0.5 μm;

[0061] S1: Place the 4.5-μm PET membrane in 50°C potassium hydroxide (5 mol / L) in a track etching treatment device, turn on the generator, release radon gas with a concentration of 3000 Bq / m 3 to etch for 0.5 hours to obtain a porous polymer layer with a porosity of 10% and a pore diameter of 0.1 μm;

[0062] S2: Place the porous polymer layer in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 0.5-μm-thick negative conductive layer on the other side by magnetron sputtering. Place it in a chromic acid aqueous solution with a concentration of 0.6 g / L for 20 seconds to deposit a 5-nm protective layer (copper-chromium oxide passivation layer) to obtain a functional current collector with a thickness of 6.005 μm.

[0063] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0064] Example 9 is based on Example 1, the difference is that the thickness of the negative conductive layer is 2.0 μm.

[0065] S1: Place the 4.5-μm PET film in 50°C potassium hydroxide (5 mol / L) in the track etching treatment device, turn on the generator, release radon gas with a concentration of 3000 Bq / m 3 and etch for 0.5 hour to obtain a porous polymer layer with a porosity of 10% and a pore diameter of 0.1 μm.

[0066] S2: Place the porous polymer layer in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 2.0-μm-thick negative conductive layer on the other side by magnetron sputtering. Place it in a chromic acid aqueous solution with a concentration of 0.6 g / L for 20 seconds to deposit a 5-nm protective layer (copper-chromium oxide passivation layer) to obtain a functional current collector with a thickness of 7.505 μm.

[0067] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0068] Example 10 is based on Example 1, the difference is that the thickness of the positive conductive layer is 0.5 μm.

[0069] S1: Place the 4.5-μm PET film in 50°C potassium hydroxide (5 mol / L) in the track etching treatment device, turn on the generator, release radon gas with a concentration of 3000 Bq / m 3Radon gas is used to etch for 0.5 hours to obtain a porous polymer layer with a porosity of 10% and a pore size of 0.1 μm;

[0070] S2: Place the porous polymer layer in the chamber of vacuum evaporation. Melt and evaporate high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200 °C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and deposit a 0.5-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a chromic acid aqueous solution of 0.6 g / L and treat it for 20 seconds to deposit a 5-nm-thick protective layer (copper chromoxide passivation layer) to obtain a functional current collector with a thickness of 6.005 μm;

[0071] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon gas is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10 °C.

[0072] Example 11 is based on Example 1; the difference is that the thickness of the positive conductive layer is 2.0 μm;

[0073] S1: Place a 4.5-μm PET film in 50 °C potassium hydroxide (5 mol / L) in a track etching treatment device, turn on the generator, and release radon gas with a concentration of 3000 Bq / m 3 Radon gas is used to etch for 0.5 hours to obtain a porous polymer layer with a porosity of 10% and a pore size of 0.1 μm;

[0074] S2: Place the porous polymer layer in the chamber of vacuum evaporation. Melt and evaporate high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200 °C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and deposit a 2-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a chromic acid aqueous solution of 0.6 g / L and treat it for 20 seconds to deposit a 5-nm-thick protective layer (copper chromoxide passivation layer) to obtain a functional current collector with a thickness of 7.505 μm;

[0075] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon gas is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10 °C.

[0076] Example 12 is based on Example 1, and the difference is that the PET film is replaced with a PP film;

[0077] S1: Place a 4.5-μm PP film in 50°C potassium hydroxide (5 mol / L) in a track etching treatment device. Turn on the generator to release radon gas with a concentration of 3000 Bq / m 3 and etch for 0.5 hour to obtain a porous polymer layer with a porosity of 10% and a pore diameter of 0.1 μm;

[0078] S2: Place the porous polymer layer in a vacuum evaporation chamber. Melt and evaporate high-purity aluminum wire (purity ≥ 99.99%) in a metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through a cooling system in the vacuum coating chamber to deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a 0.6 g / L chromic acid aqueous solution and treat for 20 seconds to deposit a 5-nm-thick protective layer (copper-chromium oxide passivation layer) to obtain a functional current collector with a thickness of 6.505 μm;

[0079] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon is the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0080] Example 13 is based on Example 1, the difference is that the PET film is replaced with a PPS film;

[0081] S1: Place a 4.5-μm PPS film in 50°C potassium hydroxide (5 mol / L) in a track etching treatment device. Turn on the generator to release radon gas with a concentration of 3000 Bq / m 3 and etch for 0.5 hour to obtain a porous polymer layer with a porosity of 10% and a pore diameter of 0.1 μm;

[0082] S2: Place the porous polymer layer in a vacuum evaporation chamber. Melt and evaporate high-purity aluminum wire (purity ≥ 99.99%) in a metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through a cooling system in the vacuum coating chamber to deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a 0.6 g / L chromic acid aqueous solution and treat for 20 seconds to deposit a 5-nm-thick protective layer (copper-chromium oxide passivation layer) to obtain a functional current collector with a thickness of 6.505 μm;

[0083] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon is the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0084] Example 14 is based on Example 1; the difference is that the etching time is 0.25 hours and the porosity of the PET porous membrane is 5%;

[0085] S1: Place a 4.5-μm PET membrane in 50°C potassium hydroxide (5 mol / L) in a track etching treatment device, turn on the generator, release radon gas with a concentration of 3000 Bq / m 3 to etch for 0.25 hours to obtain a porous polymer layer with a porosity of 5% and a pore diameter of 0.1 μm;

[0086] S2: Place the porous polymer layer in a vacuum evaporation chamber, melt and evaporate high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber to deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a 0.6 g / L chromic acid aqueous solution for 20 seconds to deposit a 5-nm protective layer (copper chromate oxide passivation layer) to obtain a functional current collector with a thickness of 6.505 μm;

[0087] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon gas is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0088] Example 15 is based on Example 1; the difference is that the etching time is 4.25 hours and the porosity of the PET porous membrane is 85%;

[0089] S1: Place a 4.5-μm PET membrane in 50°C potassium hydroxide (5 mol / L) in a track etching treatment device, turn on the generator, release radon gas with a concentration of 3000 Bq / m 3 to etch for 4.25 hours to obtain a porous polymer with a porosity of 85% and a pore diameter of 0.1 μm;

[0090] S2: Place the porous polymer layer in a vacuum evaporation chamber, melt and evaporate high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber to deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a 0.6 g / L chromic acid aqueous solution for 20 seconds to deposit a 5-nm protective layer (copper chromate oxide passivation layer) to obtain a functional current collector with a thickness of 6.505 μm;

[0091] Among them, the conditions for magnetron sputtering are as follows: a copper target (purity 99.99%) is used as the target material, the target power is 10 kW, argon is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0092] Example 16 is based on Example 1, with the difference that the radon concentration is 2500 Bq / m 3 , and the pore size of the PET porous membrane is 0.08 μm;

[0093] S1: Place a 4.5-μm PET membrane in 50°C potassium hydroxide (5 mol / L) in a track etching treatment device, turn on the generator, release radon gas with a concentration of 3000 Bq / m 3 , and etch for 0.5 hours to obtain a porous polymer layer with a porosity of 10% and a pore size of 0.1 μm;

[0094] S2: Place the porous polymer layer in the chamber of a vacuum evaporation system. Melt and evaporate high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber to deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer and deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering. Place it in a 0.6 g / L chromic acid aqueous solution and treat it for 20 seconds to deposit a 5-nm protective layer (copper chromoxide passivation layer) to obtain a functional current collector with a thickness of 6.505 μm;

[0095] Among them, the conditions for magnetron sputtering are as follows: a copper target (purity 99.99%) is used as the target material, the target power is 10 kW, argon is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0096] Example 17 is based on Example 1, with the difference that the radon concentration is 8150 Bq / m 3 , and the pore size of the PET porous membrane is 1.2 μm;

[0097] S1: Place a 4.5-μm PET membrane in 50°C potassium hydroxide (5 mol / L) in a track etching treatment device, turn on the generator, release radon gas with a concentration of 8150 Bq / m 3 , and etch for 0.5 hours to obtain a porous polymer layer with a porosity of 10% and a pore size of 1.2 μm;

[0098] S2: Place the porous polymer layer in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200 °C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering. Place it in a chromic acid aqueous solution with a concentration of 0.6 g / L and treat it for 20 seconds to deposit a 5-nm-thick protective layer (copper chromate oxide passivation layer) to obtain a functional current collector with a thickness of 6.505 μm;

[0099] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10 °C.

[0100] Example 18 is based on Example 1, the difference is that the thickness of the negative conductive layer is 0.3 μm;

[0101] S1: Place a 4.5-μm PET film in 50 °C potassium hydroxide (5 mol / L) in the track etching treatment device, turn on the generator, release radon gas with a concentration of 3000 Bq / m 3 and etch for 0.5 hours to obtain a porous polymer layer with a porosity of 10% and a pore diameter of 0.1 μm;

[0102] S2: Place the porous polymer layer in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200 °C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 0.3-μm-thick negative conductive layer on the other side by magnetron sputtering. Place it in a chromic acid aqueous solution with a concentration of 0.6 g / L and treat it for 20 seconds to deposit a 5-nm-thick protective layer (copper chromate oxide passivation layer) to obtain a functional current collector with a thickness of 5.805 μm;

[0103] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10 °C.

[0104] Example 19 is based on Example 1, the difference is that the thickness of the negative conductive layer is 2.5 μm;

[0105] S1: Place a 4.5-μm PET film in 50 °C potassium hydroxide (5 mol / L) in the track etching treatment device, turn on the generator, release radon gas with a concentration of 3000 Bq / m 3Radon gas is used to etch for 0.5 hours to obtain a porous polymer layer with a porosity of 10% and a pore size of 0.1 μm.

[0106] S2: Place the porous polymer layer in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber to deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 2.5-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a chromic acid aqueous solution of 0.6 g / L and treat it for 20 seconds to deposit a 5-nm-thick protective layer (copper chromate oxide passivation layer) to obtain a functional current collector with a thickness of 8.005 μm.

[0107] Among them, the conditions for magnetron sputtering are as follows: a copper target (purity 99.99%) is used as the target material, the target power is 10 kW, argon is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0108] Example 20 is based on Example 1, with the difference that the thickness of the positive conductive layer is 0.3 μm.

[0109] S1: Place a 4.5-μm PET film in 50°C potassium hydroxide (5 mol / L) in the track etching treatment device. Turn on the generator to release radon gas with a concentration of 3000 Bq / m 3 Radon gas is used to etch for 0.5 hours to obtain a porous polymer layer with a porosity of 10% and a pore size of 0.1 μm.

[0110] S2: Place the porous polymer layer in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber to deposit a 0.3-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a chromic acid aqueous solution of 0.6 g / L and treat it for 20 seconds to deposit a 5-nm-thick protective layer (copper chromate oxide passivation layer) to obtain a functional current collector with a thickness of 5.805 μm.

[0111] Among them, the conditions for magnetron sputtering are as follows: a copper target (purity 99.99%) is used as the target material, the target power is 10 kW, argon is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0112] Example 21 is based on Example 1, with the difference that the thickness of the positive conductive layer is 2.5 μm.

[0113] S1: Place a 4.5-μm PET film in 50°C potassium hydroxide (5 mol / L) in a track etching treatment device. Turn on the generator and release radon gas with a concentration of 3000 Bq / m 3 for 0.5 hours to obtain a porous polymer layer with a porosity of 10% and a pore diameter of 0.1 μm;

[0114] S2: Place the porous polymer layer in a vacuum evaporation chamber. Melt and evaporate high-purity aluminum wire (purity ≥ 99.99%) in a metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through a cooling system in the vacuum coating chamber to deposit a 2.5-μm-thick positive conductive layer on one surface of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other surface by magnetron sputtering; place it in a 0.6 g / L chromic acid aqueous solution for 20 seconds to deposit a 5-nm-thick protective layer (copper chromate oxide passivation layer) to obtain a functional current collector with a thickness of 8.005 μm;

[0115] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon is the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0116] Example 22 is based on Example 1, the difference being that the thickness of the PET porous membrane is 0.5 μm;

[0117] S1: Place a 0.5-μm PET film in 50°C potassium hydroxide (5 mol / L) in a track etching treatment device. Turn on the generator and release radon gas with a concentration of 3000 Bq / m 3 for 0.5 hours to obtain a porous polymer layer with a porosity of 10% and a pore diameter of 0.1 μm;

[0118] S2: Place the porous polymer layer in a vacuum evaporation chamber. Melt and evaporate high-purity aluminum wire (purity ≥ 99.99%) in a metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through a cooling system in the vacuum coating chamber to deposit a 1-μm-thick positive conductive layer on one surface of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other surface by magnetron sputtering; place it in a 0.6 g / L chromic acid aqueous solution for 20 seconds to deposit a 5-nm-thick protective layer (copper chromate oxide passivation layer) to obtain a functional current collector with a thickness of 2.505 μm;

[0119] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon is the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0120] Example 23 is based on Example 1, with the difference that the thickness of the PET film is 11 μm;

[0121] S1: Place the 11-μm PET film in 50°C potassium hydroxide (5 mol / L) in a track etching treatment device, turn on the generator, release radon gas with a concentration of 3000 Bq / m 3 to etch for 0.5 hour to obtain a porous polymer layer with a porosity of 10% and a pore diameter of 0.1 μm;

[0122] S2: Place the porous polymer layer in the chamber of a vacuum evaporation system. Melt and evaporate high-purity aluminum wire (purity ≥ 99.99%) in a metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber to deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a 0.6 g / L chromic acid aqueous solution for 20 seconds to deposit a 5-nm protective layer (copper chromate oxide passivation layer) to obtain a functional current collector with a thickness of 13.005 μm;

[0123] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon is the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0124] Example 24 is based on Example 3, with the difference that a modified PET film is used;

[0125] S1: (1) Add 1 part of 4,5-imidazole dicarboxylic acid and 0.2 part of tetrafluoroterephthalic acid to 20 parts of N,N-dimethylformamide, and mix evenly to obtain a mixed solution; (2) Add 2 parts of terephthalic acid, 1.5 parts of ethylene glycol, and 0.04 part of catalyst, set the pressure to 0.3 MPa, the temperature to 250°C, react for 20 minutes, dropwise add 0.7 part of the mixed solution and 0.8 part of ethylene glycol, finish dropping in 1.5 hours, and continue to react for 3 hours; raise the temperature to 270°C, evacuate, reduce the vacuum degree to 50 Pa, stir at 50 W / 40 Hz for 2 hours, purify and dry to obtain modified polyethylene terephthalate; use it as a raw material to melt and extrude, cast into a film, and biaxially stretch to obtain a modified PET film;

[0126] (3) Place the 4.5-μm modified PET film in 50°C potassium hydroxide (5 mol / L) in a track etching treatment device, turn on the generator, release radon gas with a concentration of 3000 Bq / m 3 to etch for 4.0 hours to obtain a porous polymer layer with a porosity of 80% and a pore diameter of 0.1 μm;

[0127] S2: Place the porous polymer layer in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a chromic acid aqueous solution of 0.6 g / L and treat it for 20 seconds to deposit a 5-nm-thick protective layer (copper chromate oxide passivation layer) to obtain a functional current collector with a thickness of 6.505 μm.

[0128] Among them, the conditions for magnetron sputtering are as follows: a copper target (purity 99.99%) is used as the target material, the target power is 10 kW, argon is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0129] Example 25, preparation method of the functional current collector;

[0130] S1: Place a 4.5-μm PET film (Yihua Toray, 4.5D08) in 50°C potassium hydroxide (5 mol / L) in the track etching treatment device, turn on the generator, release radon gas with a concentration of 8000 Bq / m 3 and etch for 4 hours to obtain a PET porous film (polymer layer) with a porosity of 80% and a pore diameter of 1 μm.

[0131] S2: Place the PET porous film in the chamber of vacuum evaporation. Melt and evaporate the high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and deposit a 1-μm-thick positive conductive layer on one surface of the PET porous film to obtain a conductive thin film.

[0132] S3: Deposit a 1-μm-thick negative conductive layer on the side of the conductive thin film where the positive conductive layer is not deposited by magnetron sputtering; place it in a chromic acid aqueous solution of 0.6 g / L and treat it for 20 seconds to deposit a 5-nm-thick protective layer (copper chromate oxide passivation layer) to obtain a functional current collector with a thickness of 6.505 μm.

[0133] Among them, the conditions for magnetron sputtering are as follows: a copper target (purity 99.99%) is used as the target material, the target power is 10 kW, argon is used as the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10°C.

[0134] Example 26 is based on Example 24, the difference is that the pore diameter of the porous polymer layer is 1 μm.

[0135] S1: (1) Add 1 part of 4,5-imidazole dicarboxylic acid and 0.2 part of tetrafluoro terephthalic acid to 20 parts of N,N-dimethylformamide, and mix evenly to obtain a mixed solution; (2) Add 2 parts of terephthalic acid, 1.5 parts of ethylene glycol, and 0.04 part of catalyst. Set the pressure to 0.3 MPa and the temperature to 250 °C, react for 20 minutes, dropwise add 0.7 part of the mixed solution and 0.8 part of ethylene glycol, finish dropping in 1.5 hours, and continue to react for 3 hours; raise the temperature to 270 °C, evacuate, reduce the vacuum degree to 50 Pa, stir at 50 W / 40 Hz for 2 hours, purify and dry to obtain modified polyethylene terephthalate; use it as a raw material to melt and extrude, cast into a film, and biaxially stretch to obtain a modified PET film;

[0136] (3) Place the 4.5-μm modified PET film in 50 °C potassium hydroxide (5 mol / L) in a track etching treatment device, turn on the generator, release radon gas with a concentration of 8000 Bq / m 3 to etch for 4 hours to obtain a porous polymer layer with a porosity of 80% and a pore size of 1 μm;

[0137] S2: Place the porous polymer layer in a vacuum evaporation chamber, melt and evaporate high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200 °C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber to deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a 0.6 g / L chromic acid aqueous solution and treat it for 20 seconds to deposit a 5-nm-thick protective layer (copper-chromium oxide passivation layer) to obtain a functional current collector with a thickness of 6.505 μm;

[0138] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon is the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10 °C.

[0139] Comparative Example 1;

[0140] Use a 13-μm aluminum foil (1060 alloy) as the substrate, and coat a 0.1-μm conductive adhesive (Benno 3318UF) on its surface; then laminate it with a 4.5-μm electrolytic copper foil and bake it in an oven at 150 °C for 10 minutes to obtain a functional current collector with a thickness of 17.5 μm.

[0141] Comparative Example 2 is based on Example 24, the difference is that tetrafluoro terephthalic acid is not introduced into the modified polyethylene terephthalate;

[0142] S1: (1) Add 1 part of 4,5-imidazole dicarboxylic acid to 20 parts of N,N-dimethylformamide and mix evenly to obtain a mixed solution; (2) Add 2 parts of terephthalic acid, 1.5 parts of ethylene glycol, and 0.04 part of catalyst. Set the pressure to 0.3 MPa and the temperature to 250 °C, react for 20 minutes, then dropwise add 0.7 part of the mixed solution and 0.8 part of ethylene glycol, finish dropping in 1.5 hours, and continue to react for 3 hours; raise the temperature to 270 °C, evacuate, reduce the vacuum degree to 50 Pa, stir at 50 W / 40 Hz for 2 hours, purify and dry to obtain modified polyethylene terephthalate; use it as a raw material to melt and extrude, cast into a film, and biaxially stretch to obtain a modified PET film;

[0143] (3) Place the 4.5-μm modified PET film in 50 °C potassium hydroxide (5 mol / L) in a track etching treatment device, turn on the generator, release radon gas with a concentration of 3000 Bq / m 3 and etch for 4.0 hours to obtain a porous polymer layer with a porosity of 80% and a pore size of 0.1 μm;

[0144] S2: Place the porous polymer layer in the chamber of vacuum evaporation, melt and evaporate high-purity aluminum wire (purity ≥ 99.99%) in the metal evaporation chamber at a high temperature of 1200 °C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber to deposit a 1-μm-thick positive conductive layer on one side of the porous polymer layer; deposit a 1-μm-thick negative conductive layer on the other side by magnetron sputtering; place it in a 0.6 g / L chromic acid aqueous solution and treat for 20 seconds to deposit a 5-nm-thick protective layer (copper-chromium oxide passivation layer) to obtain a functional current collector with a thickness of 6.505 μm;

[0145] Among them, the conditions for magnetron sputtering are: using a copper target (purity 99.99%) as the target material, the target power is 10 kW, argon is the gas source, the gas flow rate is 80 mL / min, the air pressure in the chamber during operation is 0.08 Pa, and the main roller cooling temperature is -10 °C.

[0146] Detection test: 1. Test the surface density, pinhole defects, and defect rate caused by film breakage during film formation of the functional current collectors in Examples 1-26 and Comparative Examples 1-2 as follows:

[0147] (1) Surface density: Cut the functional current collectors in Examples 1-26 and Comparative Examples 1-2 into 100 mm × 100 mm respectively through a sampler, weigh the mass respectively, and calculate the ratio of mass to area to obtain the surface density of the functional current collector, as shown in Table 1;

[0148] (2) Number of pinhole defects: Place the functional current collectors of Examples 1 to 26 and Comparative Examples 1 to 2 in a pinhole defect detection system (microscopic charge-coupled device CCD), scan them, then convert the optical signal into an electrical signal and transmit it to a computer to count the number of pinhole defects in the functional current collectors of Examples 1 to 26 and Comparative Examples 1 to 2, as shown in Table 1;

[0149] (3) Calculate the defect rate caused by film breakage during the preparation of the functional current collectors in Examples 1 to 26 and Comparative Examples 1 to 2, as shown in Table 1;

[0150] Defect rate caused by film breakage (%) = (Number of unqualified products caused by film breakage / Total number of products) × 100%;

[0151] Among them, the unit of quantity is m 2 ; The unqualified products caused by film breakage refer to the products produced and wound before film breakage; The total number of products refers to the total input quantity, which is equal to the sum of the number of qualified finished products and the number of unqualified products caused by film breakage, which is 5000 m 2 .

[0152] (4) Corrosion resistance test: Take 6 functional current collectors from Examples 1 to 3, Examples 24 to 26 and Comparative Examples 1 to 2 respectively. After testing their tensile strength, place them in Li6PS5Cl as a solid electrolyte and soak for 120 hours at a temperature of 80°C; After soaking, test the tensile strength of the samples and calculate the tensile strength retention rate after acid corrosion, as shown in Table 2.

[0153] 2. Use Examples 1 to 26 and Comparative Examples 1 to 2 for performance testing of lithium battery membranes;

[0154] (1) Battery assembly: (a) Prepare a positive electrode material by mixing LiNi0.8Co0.1Mn0.1O2 (NCM811), conductive carbon black Super P, PVDF5130, and carbon nanotubes CNT in a mass ratio of 96:1.8:1.7:0.5, and coat it on the positive electrode conductive layers of Examples 1 to 26 and Comparative Examples 1 to 2 respectively; (b) Then prepare a negative electrode material by mixing graphite, conductive carbon black Super P, carbon nanotubes, and CMC in a mass ratio of 96:3.0:0.6:0.4, and coat it on the negative electrode conductive layers of Examples 1 to 26 and Comparative Examples 1 to 2 respectively; (c) Use Li6PS5Cl as a solid electrolyte and assemble soft-pack batteries with a capacity of 3 Ah respectively according to the assembly process of bipolar solid-state batteries;

[0155] (2) Battery cycling performance: The assembled battery mentioned above was subjected to a cycling performance test; Test conditions: Charge at a constant current and constant voltage (CCCV) method at a rate of 1C, discharge at a constant current (CC) at a rate of 1C, perform 2000 cycles of charge and discharge, and record the battery capacity retention rate after 2000 cycles of charge and discharge, as shown in Table 1; The battery capacity retention rate is (the battery capacity after 2000 cycles of charge and discharge / the initial capacity of the battery) × 100%.

[0156]

[0157] Table 1

[0158]

[0159]

[0160] Table 2

[0161] Conclusion: It can be seen from Examples 1 to 23 and Comparative Example 1 that; compared with traditional functional current collectors, the areal density and the number of pinhole defects of the functional current collector prepared by the present invention are significantly reduced; the reduction of the areal density can reduce the mass of the battery prepared with this functional current collector, thereby improving the energy density of the battery, and can realize the application of this functional current collector in flexible batteries; the reduction of the number of pinhole defects improves the cycling performance and the battery capacity retention rate of the battery prepared with this functional current collector.

[0162] It can be seen from Examples 1 to 3, 14, and 15 that; by increasing the porosity of the polymer film, the areal density of the prepared functional current collector is reduced; the number of pinhole defects of the prepared functional current collector remains unchanged first and then increases, which is due to too high porosity; the cycling performance of the battery first improves and then decreases; this is because increasing the porosity of the polymer film can increase the contact area with the positive and negative electrode conductive layers, thereby improving the conductivity between the two, reducing the interfacial resistance, and thus improving the cycling performance of the battery; while too high porosity leads to the appearance of pinhole defects in the functional current collector, thereby reducing the cycling performance of the battery; in addition, too high porosity will lead to an increase in the defective rate caused by film breakage during the preparation of the functional current collector.

[0163] It can be seen from Examples 1, 4, 5, 16, and 17 that; by increasing the pore size of the polymer film, the number of pinhole defects of the prepared functional current collector remains unchanged first and then increases, which is due to too high porosity; the cycling performance of the battery first improves and then decreases; this is because increasing the pore size of the polymer film can increase the single-point contact area with the positive and negative electrode conductive layers, thereby improving the conductivity between the two, reducing the interfacial resistance, and thus improving the cycling performance of the battery; while too high pore size leads to the appearance of pinhole defects in the functional current collector, thereby reducing the cycling performance of the battery.

[0164] It can be seen from Examples 1, 6, 7, 22, and 23 that increasing the thickness of the polymer film results in an increase in the areal density of the functional current collector; during the preparation of the functional current collector, the defect rate caused by film breakage first decreases and then remains unchanged, that is, the thickness of the polymer film should not be too thin, as it is prone to film breakage; the cycle performance of the prepared battery is improved, but when the thickness exceeds 4.5 μm and the thickness continues to increase, the improvement in the battery cycle performance is not obvious. Considering the influence of the areal density, the thickness of the polymer film is preferably 1 - 10 μm.

[0165] It can be seen from Examples 1, 8, 9, 18, and 19 that increasing the thickness of the negative electrode conductive layer results in an increase in the areal density of the prepared functional current collector; the cycle performance of the prepared battery is improved, which is due to the improved conductivity; considering the energy density and cycle performance of the battery, the thickness of the negative electrode conductive layer of the functional current collector is preferably 0.5 - 2 μm.

[0166] It can be seen from Examples 1, 10, 11, 20, and 21 that increasing the thickness of the positive electrode conductive layer results in an increase in the areal density of the prepared functional current collector; the cycle performance of the prepared battery is improved, which is due to the improved conductivity; considering the energy density and cycle performance of the battery, the thickness of the positive electrode conductive layer of the functional current collector is preferably 0.5 - 2 μm.

[0167] It can be seen from Examples 1 - 3 that when the porosity is increased, the corrosion resistance of the functional current collector decreases; however, the other properties of the functional current collector in Example 3 are optimal; Example 24 is based on Example 3, the difference being the use of a modified PET film, thereby improving the performance of the current collector; it is found that based on Example 24, after increasing the pore size of the PET porous film (polymer layer) to 1 μm, the corrosion resistance and capacity retention rate of the functional current collector are improved; Comparative Example 2 is based on Example 24, the difference being that tetrafluoroterephthalic acid is not introduced into the modified polyethylene terephthalate, and it is found that the performance of the functional current collector deteriorates.

[0168] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above - mentioned exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, in any regard, the embodiments should be regarded as exemplary and non - restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed within the present invention.

Claims

1. A functional fluid collector, characterized in that: The structure of the functional current collector comprises a negative electrode conductive layer, a porous polymer layer and a positive electrode conductive layer in sequence.

2. The functional current collector according to claim 1, characterized in that: The thickness of the negative electrode conductive layer is 0.5 to 2 μm; the thickness of the polymer layer is 1.0 to 10 μm; and the thickness of the positive electrode conductive layer is 0.5 to 2 μm.

3. The functional current collector according to claim 1, characterized in that: The porosity of the porous polymer layer is 10% to 80%, and the pore diameter is 0.1 to 1 μm.

4. The method for preparing a functional current collector according to claim 1, characterized in that: The steps include: S1: placing the polymer film in a potassium hydroxide solution at 45-55° C. in a track etching treatment device, introducing radon gas, and etching for 0.5-4 hours to obtain a porous polymer layer; S2: depositing a positive electrode conductive layer on one side of the porous polymer layer and depositing a negative electrode conductive layer on the other side to obtain a functional current collector.

5. The method for preparing a functional current collector according to claim 4, characterized in that: The material of the polymer film includes one or more of polyethylene terephthalate, polypropylene, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene oxide, polystyrene, and polyimide; The concentration of the potassium hydroxide solution is 4-6 mol / L; the amount of radon gas introduced is 2500-3500 Bq / m 3 ; The material of the positive electrode conductive layer includes one or more of aluminum, carbon, gold, silver and their alloys; the material of the negative electrode conductive layer includes one or more of copper, nickel, titanium, carbon, gold, silver and their alloys.

6. The method for preparing a functional current collector according to claim 5, characterized in that: When the negative electrode conductive layer is a copper layer, a protective layer is provided on the surface of the negative electrode conductive layer, and the thickness of the protective layer is 5 to 100 nm; the material of the protective layer includes one or more of nickel, chromium, nickel-based alloy, copper-based alloy, aluminum oxide, silicon oxide, nickel oxide, chromium oxide, cobalt oxide, graphite, carbon black, copper-chromium oxide, carbon nano-quantum dots, carbon nanotubes, carbon nanofibers, and graphene; The method for setting the protective layer includes one of physical vapor deposition, chemical vapor deposition, in-situ molding, and coating.

7. The method for preparing a functional current collector according to claim 4, characterized in that: The deposition method of the positive electrode conductive layer and the negative electrode conductive layer comprises one of magnetron sputtering and vacuum evaporation.

8. The method for preparing a functional current collector according to claim 7, characterized in that: The conditions of the magnetron sputtering are: power of 8-15 kW, argon as the gas source, gas flow rate of 75-85 mL / min, gas pressure of 0.05-0.08 Pa, main roller cooling temperature of -10--20°C; the conditions of the vacuum evaporation are: melting evaporation temperature of 1200-4000°C, vacuum degree of 5×10 -3 ~5×10 -2 Pa.

9. The method for preparing a functional current collector according to claim 5, characterized in that: The polymer film is a modified PET film, and its preparation method is as follows: (1) adding 4,5-imidazoledicarboxylic acid and tetrafluoroterephthalic acid to N,N-dimethylformamide, uniformly mixing to obtain a mixed solution; (2) setting the pressure of terephthalic acid, ethylene glycol and a catalyst to 0.3-0.4 MPa and the temperature to 230-250°C, reacting for 20-30 minutes, dripping the mixed solution and ethylene glycol, dripping for 1-2 hours, and continuing the reaction for 3-4 hours; heating to 270-280°C, evacuating, reducing the vacuum degree to 50-60 Pa, stirring at 20-50W / 40Hz for 1-2 hours, purifying, and drying to obtain modified polyethylene terephthalate; using it as a raw material for melt extrusion, film casting, and biaxial stretching to obtain a modified PET film.

10. The method for preparing a functional current collector according to claim 9, characterized in that: The raw materials of the mixed solution include the following components: 1 to 2 parts of 4,5-imidazoledicarboxylic acid, 0.2 to 0.3 parts of tetrafluoroterephthalate, and 20 to 30 parts of N,N-dimethylformamide, by weight; the raw materials of the modified polyethylene terephthalate include the following components: 1.7 to 2.7 parts of terephthalic acid, 1.5 to 2.3 parts of ethylene glycol, 0.5 to 1 part of the mixed solution, and 0.02 to 0.05 parts of a catalyst, by weight.

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