Current collector, battery and method for processing a current collector

Abstract

The present disclosure relates to a current collector, a battery and a processing method of the current collector. The current collector comprises a substrate and aluminum film layers arranged on both sides of the substrate. The overall structure of the substrate sandwiched between the two aluminum film layers can reduce the overall thickness of the current collector and the battery and improve the tensile strength of the current collector and the battery by virtue of the lightness and good stretchability of the substrate. The substrate comprises a polymer base layer and conductive particles added in the polymer base layer. The conductive particles can cooperate with the aluminum film layers on both sides of the polymer base layer to ensure the conductivity of the current collector.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of electronic technology, and in particular to a current collector, a battery and a processing method of the current collector. BACKGROUND

[0002] A battery such as a lithium ion battery includes a current collector for storing battery active materials, and the current collector is used to collect the current generated by the battery active materials to form an output current.

[0003] In the related art, the positive electrode current collector of the battery can be an aluminum foil. In order to make the battery have high energy density, light weight and flexibility, it is necessary to thin the aluminum foil, but due to the limitations of the preparation technology, the thickness of the aluminum foil is limited, and after the aluminum foil is thinned, the mechanical strength and performance are reduced, which affects the overall performance of the battery. SUMMARY

[0004] The present disclosure provides a current collector, a battery and a processing method of the current collector, to improve the thinness of the current collector and the battery while ensuring the conductivity of the current collector.

[0005] According to a first aspect of the present disclosure, a current collector applied to a battery positive electrode is provided, and the current collector comprises:

[0006] a base body comprising a polymer base layer and conductive particles arranged on the polymer base layer; the polymer base layer is provided with a first outer surface on one side in the thickness direction and a second outer surface on the other side, and the conductive particles are arranged inside the polymer base layer between the first outer surface and the second outer surface;

[0007] an aluminum film layer arranged on the first outer surface and the second outer surface, so that the base body is sandwiched between the aluminum film layers.

[0008] Optionally, the aluminum film layer covers the first outer surface and / or the second outer surface.

[0009] Optionally, the thickness of the base body is greater than or equal to 2 microns and less than or equal to 12 microns.

[0010] Optionally, the addition ratio of the conductive particles relative to the base body is greater than or equal to 0.01wt% and less than or equal to 30wt%.

[0011] Optionally, the material of the conductive particles comprises at least one of carbon nanotubes, graphene, conductive carbon black, silver, aluminum and copper.

[0012] Optionally, the polymer base layer is provided with at least two kinds of conductive particles.

[0013] Optionally, the polymer base layer comprises a main area and a functional area connected to the main area, the aluminum film layer covers the main area, and the conductive particles are uniformly distributed in the main area.

[0014] Optionally, the material of the polymer base layer comprises at least one of polyvinylidene fluoride, polyvinylidene chloride-hexafluoropropylene, polytetrafluoroethylene, polyethylene oxide, polyester, polyamide, polyamide-imide, polymethyl methacrylate, polycarbonate, carboxymethyl cellulose, styrene-butadiene copolymer, polyacrylic acid, lithium polyacrylate, polyacrylonitrile, sodium carboxymethyl cellulose, and butadiene rubber.

[0015] Optionally, the thickness of the aluminum film layer is greater than or equal to 100 nanometers and less than or equal to 2000 nanometers.

[0016] According to a second aspect of the present disclosure, a battery is provided, which comprises any of the current collectors according to the first aspect.

[0017] According to a third aspect of the present disclosure, a current collector processing method is provided, which is applied to any of the current collectors according to the first aspect, and the current collector processing method comprises:

[0018] adding conductive particles into the polymer base layer to form a matrix;

[0019] setting an aluminum film layer on both sides of the matrix.

[0020] Optionally, adding conductive particles into the polymer base layer comprises:

[0021] stirring the conductive particles, the polymer, and the solvent in a magnetic stirrer until uniform, and standing for defoaming to obtain a spinning solution;

[0022] embedding the conductive particles into the polymer base layer by using an electrospinning device to prepare the matrix.

[0023] Optionally, the solvent comprises at least one of N,N-dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, water, acetone, ethanol, methanol, acetonitrile, benzene, and toluene.

[0024] Optionally, the preparation parameters of the electrospinning device comprise:

[0025] the voltage is greater than or equal to 1 KV and less than or equal to 100 KV;

[0026] and / or, the flow rate is greater than or equal to 0.05 L / h and less than or equal to 10 L / h;

[0027] and / or, the cavity temperature is greater than or equal to 20℃ and less than or equal to 150℃.

[0028] Optionally, aluminum film layers are arranged on both sides of the base body, comprising:

[0029] Carrying out corona treatment on the surface of the polymer base layer;

[0030] Placing the polymer base layer after corona treatment into the vacuum chamber of the evaporation film coating machine, and vacuumizing the vacuum chamber to a preset vacuum degree;

[0031] After the evaporation film coating machine is warmed up to a preset temperature, aluminum is sent to the evaporation film coating machine to form the aluminum film layers on the surface of the moving polymer base layer.

[0032] The technical solution provided by the embodiments of the present disclosure can include the following beneficial effects:

[0033] The current collector of the present disclosure comprises a base body and aluminum film layers arranged on both sides of the base body. The overall structure of the base body sandwiched between the two aluminum film layers can reduce the overall thickness of the current collector and the battery by virtue of the lightness and good stretchability of the base body, and improve the tensile strength of the current collector and the battery. The base body comprises a polymer base layer and conductive particles added in the polymer base layer. The conductive particles can cooperate with the aluminum film layers on both sides of the polymer base layer to ensure the conductivity of the current collector.

[0034] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0035] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present disclosure and, together with the specification, serve to explain the principles of the present disclosure.

[0036] Figure 1 is a cross-sectional structure diagram of a current collector in an exemplary embodiment of the present disclosure;

[0037] Figure 2 is a flowchart of a current collector processing method in an exemplary embodiment of the present disclosure;

[0038] Figure 3 is a flowchart of a current collector processing method in another exemplary embodiment of the present disclosure;

[0039] Figure 4 is a flowchart of a current collector processing method in yet another exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0040] The exemplary embodiments will be described in detail below with reference to the accompanying drawings. In the following description, unless otherwise indicated, like numbers in the different figures represent the same or similar elements. The following exemplary embodiments described are not meant to represent all embodiments consistent with the present disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0041] A battery such as a lithium ion battery includes a current collector for storing battery active materials, which is used to collect the current generated by the battery active materials to form the current output to the outside. In the related art, the positive electrode current collector of the battery can be an aluminum foil. In order to obtain high energy density, light weight and flexibility of the battery, the aluminum foil needs to be thinned, but due to the limitations of the preparation technology, the thickness of the aluminum foil is limited, and after the aluminum foil is thinned, the mechanical strength and performance are reduced, which affects the overall performance of the battery.

[0042] The present disclosure provides a current collector applied to a battery positive electrode. Figure 1 is a schematic view of a cross-sectional structure of a current collector in an exemplary embodiment of the present disclosure. As shown in Figure 1 The current collector 1 includes a substrate 11 and an aluminum film layer 12. The substrate 11 includes a polymer base layer 111 and conductive particles 112 arranged on the polymer base layer 111. The polymer base layer 111 is provided with a first outer surface 1111 on one side in the thickness direction and a second outer surface 1112 on the other side. The conductive particles 112 are arranged inside the polymer base layer 111 between the first outer surface 1111 and the second outer surface 1112. The aluminum film layer 12 is arranged on the first outer surface 1111 and the second outer surface 1112, so that the substrate 11 is sandwiched between the aluminum film layer 12.

[0043] Since the current collector 1 includes the substrate 11 and the aluminum film layer 12 arranged on both sides of the substrate 11, the overall structure of the substrate 11 sandwiched between the two aluminum film layers 12 can reduce the overall thickness of the current collector 1 and the battery by virtue of the lightness and good stretchability of the substrate 11, and improve the tensile strength of the current collector 1 and the battery, so that the current collector 1 has better mechanical properties, and also helps to improve the energy density of the battery. The substrate 11 includes the polymer base layer 111 and the conductive particles 112 added in the polymer base layer 111, and the conductive particles 112 can cooperate with the aluminum film layer 12 on both sides of the polymer base layer 111 to ensure the conductivity of the current collector 1.

[0044] In some embodiments, the aluminum film layer 12 can cover the first outer surface 1111 and / or the second outer surface 1112. For example, the aluminum film layer 12 covers the first outer surface 1111 and the second outer surface 1112, so that the aluminum film layer 12 can cooperate with the conductive particles 112 in the polymer base layer 111 to achieve better conductivity. For another example, the aluminum film layer 12 on the side of the first outer surface 1111 can cover part of the first outer surface 1111, and the aluminum film layer 12 on the side of the second outer surface 1112 can cover the second outer surface 1112. In this case, the section of the current collector 1 corresponding to the area of the first outer surface 1111 not covered by the aluminum film layer 12 can serve as a tab for charging and discharging the battery cell. The above tab structure can avoid short circuit and other problems caused by bending at the tab.

[0045] In some embodiments, the polymer base layer 111 can include a main area and a functional area connected to the main area, and the aluminum film layer 12 covers the main area and the conductive particles 112 are uniformly distributed in the main area. The main area can be used to achieve the basic function of the current collector 1, and the functional area can be used to set the tab and other functional structures. Distributing the conductive particles 112 in the main area can improve the conductivity of the base 11 cooperating with the aluminum film layer 12 and improve the utilization rate of the conductive particles 112.

[0046] In some embodiments, the thickness of the base 11 can be greater than or equal to 2 microns and less than or equal to 12 microns. Since the current collector 1 includes the base 11 and the aluminum film layers 12 arranged on both sides of the base 11, the aluminum film layers 12 can achieve the conductivity function, so the base 11 formed by the polymer base layer 111 can reduce the thickness to be greater than or equal to 2 microns and less than or equal to 12 microns, which reduces the thickness by 20%-40% and the weight by 40%-60% relative to the original current collector 1 while improving the tensile strength of the current collector 1.

[0047] The polymer base layer 111 as the main material of the base 11 has better tensile strength, so that the tension, pressure and other windows in the preparation process are improved, so that a higher pressure can be used in the material preparation section to achieve a larger compaction density, thereby improving the process manufacturing capacity.

[0048] It should be noted that the material of the polymer base layer 111 can include at least one of polyvinylidene fluoride, polyvinylidene chloride-hexafluoropropylene, polytetrafluoroethylene, polyethylene oxide, polyester, polyamide, polyamide-imide, polymethyl methacrylate, polycarbonate, carboxymethyl cellulose, styrene-butadiene copolymer, polyacrylic acid, lithium polyacrylate, polyacrylonitrile, sodium carboxymethyl cellulose, and butadiene-styrene rubber.

[0049] In some embodiments, at least two conductive particles 112 can be added inside the polymer base layer 111. Adding multiple conductive particles 112 inside the polymer base layer 111 can comprehensively utilize the performance of each conductive particle 112, thereby improving the overall conductive performance of the current collector 1.

[0050] It should be noted that the material of the conductive particles 112 can include at least one of carbon nanotubes, graphene, conductive carbon black, silver, aluminum, and copper. In addition, the addition ratio of the conductive particles 112 to the base 11 is greater than or equal to 0.01wt% and less than or equal to 30wt%, so as to improve the overall conductive effect of the current collector 1 under the condition of controlling the manufacturing cost, process difficulty, etc.

[0051] In some embodiments, the thickness of the aluminum film layer 12 can be greater than or equal to 100 nanometers and less than or equal to 2000 nanometers. Since the aluminum film layer 12 is arranged on both sides of the polymer base layer 111, the current collector 1 has sufficient mechanical strength and conductive performance, thereby reducing the thickness of the current collector 1, improving the energy density of the battery, reducing the cost, and helping to realize the lightweight of the battery.

[0052] The present disclosure further provides a current collector processing method applied to the current collector 1. Figure 2 is a flowchart of a current collector processing method in an exemplary embodiment of the present disclosure. As shown in Figure 2 The current collector 1 processing method can be implemented by the following steps:

[0053] In step S201, conductive particles 112 are added in the polymer base layer 111 to form the base 11.

[0054] It should be noted that the material of the polymer base layer 111 can include at least one of polyvinylidene fluoride, polyvinylidene chloride-hexafluoropropylene, polytetrafluoroethylene, polyethylene oxide, polyester, polyamide, polyamide-imide, polymethyl methacrylate, polycarbonate, carboxymethyl cellulose, styrene-butadiene copolymer, polyacrylic acid, lithium polyacrylate, polyacrylonitrile, sodium carboxymethyl cellulose, and butadiene rubber.

[0055] The material of the conductive particles 112 can include at least one of carbon nanotubes, graphene, conductive carbon black, silver, aluminum, and copper. In addition, the addition ratio of the conductive particles 112 to the base 11 is greater than or equal to 0.01wt% and less than or equal to 30wt%, so as to improve the overall conductive effect of the current collector 1 under the condition of controlling the manufacturing cost, process difficulty, etc.

[0056] In step S202, an aluminum film layer 12 is arranged on both sides of the base 11.

[0057] The whole structure of the current collector 1 including the substrate 11 and the aluminum film layers 12 arranged on both sides of the substrate 11 can reduce the overall thickness of the current collector 1 and the battery and improve the tensile strength of the current collector 1 and the battery by virtue of the lightness and good stretchability of the substrate 11, so that the current collector 1 has better mechanical properties and the energy density of the battery is improved. The substrate 11 includes a polymer base layer 111 and conductive particles 112 added in the polymer base layer 111, and the conductive particles 112 can cooperate with the aluminum film layers 12 on both sides of the polymer base layer 111 to ensure the conductivity of the current collector 1.

[0058] Figure 3 is a flow chart of a current collector processing method in another exemplary embodiment of the present disclosure, as shown in Figure 3 In the embodiment shown in the figure, the conductive particles 112 added in the polymer base layer 111 can be realized by the following steps:

[0059] In step S301, the conductive particles 112, the polymer, and the solvent are stirred in a magnetic stirrer until they are uniform, and then they are left to stand to remove bubbles to obtain a spinning solution.

[0060] The conductive particles 112, the polymer, and the solvent are stirred in a magnetic stirrer until they are uniform, and the concentration of the solvent can be 2wt%-20wt%, and then they are left to stand for 10min to remove bubbles to obtain a spinning solution.

[0061] The solvent can include at least one of N,N-dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, water, acetone, ethanol, methanol, acetonitrile, benzene, and toluene.

[0062] In step S302, the conductive particles 112 are embedded in the polymer base layer 111 by using an electrostatic spinning device to prepare the substrate 11.

[0063] The spinning solution is loaded into an instrument device, the instrument device is installed, the electrostatic spinning device is connected, the current collector 1 is placed on a receiving screen, the flow rate, the voltage, and the cavity temperature are adjusted, and the substrate 11 containing the conductive particles 112 is prepared.

[0064] The preparation parameters of the electrostatic spinning device can include voltage, flow rate, cavity temperature, etc. The voltage can be greater than or equal to 1KV and less than or equal to 100KV. And / or, the flow rate can be greater than or equal to 0.05L / h and less than or equal to 10L / h. And / or, the cavity temperature can be greater than or equal to 20℃ and less than or equal to 150℃.

[0065] Figure 4 is a flow chart of a current collector processing method in another exemplary embodiment of the present disclosure, as shown in Figure 4In the embodiment shown, the aluminum film layer 12 provided on both sides of the base body 11 can be achieved by the following steps:

[0066] In step S401, the surface of the polymer base layer 111 is subjected to corona treatment.

[0067] In step S402, the polymer base layer 111 subjected to corona treatment is placed in the vacuum chamber of an evaporation film coating machine, and the vacuum chamber is evacuated to a preset vacuum degree.

[0068] In step S403, the evaporation film coating machine is heated to a preset temperature, and aluminum is fed to the evaporation film coating machine to form an aluminum film layer 12 on the surface of the moving polymer base layer 111.

[0069] The surface of the polymer base layer 111 to be plated with aluminum is subjected to corona treatment, and the obtained polymer base layer 111 is placed in the vacuum chamber of a double-sided reciprocating evaporation film coating machine, the vacuum chamber is sealed, and is gradually evacuated to a vacuum degree of 4x10 -2 -6x10 -2 Pa. The evaporation mechanism is heated to 1300-1400℃, aluminum is fed to the evaporation mechanism, the unwinding speed, winding speed and evaporation amount are adjusted, the aluminum is continuously melted and evaporated in the evaporation mechanism, and an aluminum film layer 12 is formed on the surface of the moving polymer base layer 111.

[0070] The disclosure further provides a battery comprising the current collector 1 described above. The current collector 1 described above can be applied to the positive electrode of the battery.

[0071] It should be noted that the battery described above can be applied to mobile phones, wearable devices, tablet computers, televisions, advertising screens, vehicle-mounted terminals, medical terminals, etc., and the disclosure is not limited in this regard.

[0072] Since the current collector 1 comprises the base body 11 and the aluminum film layers 12 provided on both sides of the base body 11, the overall structure of the base body 11 sandwiched between the two aluminum film layers 12 can reduce the overall thickness of the current collector 1 and the battery by virtue of the lightness and good stretchability of the base body 11, improve the tensile strength of the current collector 1 and the battery, and make the current collector 1 have better mechanical properties, while helping to improve the energy density of the battery. The base body 11 comprises the polymer base layer 111 and the conductive particles 112 added in the polymer base layer 111, and the conductive particles 112 can cooperate with the aluminum film layers 12 on both sides of the polymer base layer 111 to ensure the conductivity of the current collector 1.

[0073] Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the features of the disclosure as disclosed herein. It is intended that the disclosure be construed as including any variations, uses, or adaptations of the specific embodiments following, including equivalents thereof, which are within the scope of the disclosure and including such as come within the general scope of the following claims. The specification and examples are to be regarded as exemplary only, and the true scope and spirit of the disclosure are indicated by the following claims.

[0074] It is to be understood that the disclosure is not limited to the precise construction here described and illustrated in the accompanying drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the disclosure. The scope of the disclosure is limited only by the claims that follow.

Claims

1. A current collector characterized by comprising: The current collector (1) is applied to a positive electrode of a battery, and comprises: a base body (11) comprising a polymer base layer (111) and conductive particles (112) arranged in the polymer base layer (111); one side of the polymer base layer (111) in a thickness direction is provided with a first outer surface (1111), and the other side is provided with a second outer surface (1112); the conductive particles are arranged inside the polymer base layer (111) between the first outer surface (1111) and the second outer surface (1112); an aluminum film layer (12) arranged on the first outer surface (1111) and the second outer surface (1112) so that the base body (11) is clamped between the aluminum film layer (12); the polymer base layer (111) comprises a main body region and a functional region connected to the main body region; the aluminum film layer (12) covers the main body region, and the conductive particles (112) are uniformly distributed in the main body region; the aluminum film layer (12) on the side of the second outer surface (1112) covers the second outer surface (1112), and the aluminum film layer (12) on the side of the first outer surface (1111) covers part of the first outer surface (1111); a segment of the current collector (1) corresponding to an area of the first outer surface (1111) not covered by the aluminum film layer (12) serves as a tab.

2. The current collector of claim 1, wherein The thickness of the base body (11) is greater than or equal to 2 microns and less than or equal to 12 microns.

3. The current collector of claim 1, wherein The addition ratio of the conductive particles (112) relative to the base body (11) is greater than or equal to 0.01 wt % and less than or equal to 30 wt %.

4. The current collector of claim 1, wherein The material of the conductive particles (112) comprises at least one of carbon nanotubes, graphene, conductive carbon black, silver, aluminum, and copper.

5. The current collector of claim 1, wherein At least two kinds of the conductive particles (112) are arranged inside the polymer base layer (111).

6. The current collector of claim 1, wherein The material of the polymer base layer (111) comprises at least one of polyvinylidene fluoride, polyvinylidene-hexafluoropropylene, polytetrafluoroethylene, polyethylene oxide, polyester, polyamide, polyamide-imide, carboxymethyl cellulose, styrene-butadiene copolymer, polyacrylic acid, lithium polyacrylate, polyacrylonitrile, and sodium carboxymethyl cellulose.

7. The current collector of claim 6, wherein The polyester comprises polymethyl methacrylate and polycarbonate.

8. The current collector of claim 1, wherein The thickness of the aluminum film layer (12) is greater than or equal to 100 nanometers and less than or equal to 2000 nanometers.

9. A battery, characterized by The current collector (1) comprises the base body (11) according to any one of claims 1-8.

10. A method of processing a current collector, characterized by, The current collector (1) is applied to the current collector (1) according to any one of claims 1-8, and a processing method of the current collector (1) comprises: adding the conductive particles (112) in the polymer base layer (111) to form the base body (11); arranging the aluminum film layer (12) on both sides of the base body (11).

11. The current collector processing method of claim 10, wherein The adding of the conductive particles (112) in the polymer base layer (111) comprises: placing the conductive particles (112), the polymer, and a solvent in a magnetic stirrer to stir until uniform, and standing to defoam to obtain a spinning solution; embedding the conductive particles (112) in the polymer base layer (111) by using an electrostatic spinning device to prepare the base body (11).

12. The current collector processing method of claim 11, wherein The solvent includes at least one of N, N-dimethylformamide, N-methyl pyrrolidone, tetrahydrofuran, water, acetone, ethanol, methanol, acetonitrile, benzene and toluene.

13. The current collector processing method of claim 11, wherein The preparation parameters of the electrostatic spinning device include: The voltage is greater than or equal to 1KV and less than or equal to 100KV; And / or, the flow rate is greater than or equal to 0.05L / h and less than or equal to 10L / h; And / or, the cavity temperature is greater than or equal to 20℃ and less than or equal to 150℃.

14. The current collector fabrication method of claim 11, wherein An aluminum film layer (12) is arranged on both sides of the base (11), including: Carrying out corona treatment on the surface of the polymer base layer (111); Placing the polymer base layer (111) after corona treatment into the vacuum chamber of the evaporation coating machine, and vacuumizing the vacuum chamber to a preset vacuum degree; After the evaporation coating machine is warmed up to a preset temperature, aluminum is sent to the evaporation coating machine to form the aluminum film layer (12) on the surface of the moving polymer base layer (111).

Images