Self-heating battery current collector, self-heating battery cell, and self-heating battery and preparation method thereof

Abstract

The application relates to the technical field of batteries, and particularly discloses a self-heating battery current collector, which comprises a graphene heating layer coated on a base material; a first conductive strip and a second conductive strip oppositely arranged on two sides of the surface of the base material and in contact with the graphene heating layer; a packaging layer covering the base material and forming a closed interlayer with the base material, the closed interlayer completely wrapping the first conductive strip, the second conductive strip and the graphene heating layer; and a current collecting conductor layer coated on the outer surface of the base material away from the graphene heating layer. The current collecting conductor layer is coated on the outer surface of the base material away from the graphene heating layer, and cooperates with the graphene heating layer to heat, so that the self-heating film can achieve the technical effect of a large heating piece area under the condition of a small heating space, the self-heating film has a small heating specific power, can heat for a long time under the condition of low voltage and small current, is beneficial to long-term maintenance of the optimal balanced temperature required by a solid-state battery, and guarantees the current collecting effect of the battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a self-heating battery current collector, a self-heating battery cell, a self-heating battery and a preparation method thereof. BACKGROUND

[0002] In recent years, new energy vehicles and energy storage industries have developed rapidly, and power batteries and energy storage batteries have entered the fast lane. Safety accidents caused by batteries occur from time to time, and the safety performance of power batteries has become an important consideration for users when purchasing electric vehicles. It can be said that whether the balanced battery electrochemical reaction temperature can be continuously maintained has become a roadblock for the commercialization of solid-state batteries.

[0003] At present, most of the battery heating methods are to heat the battery cell outside the battery cell shell, or to heat the battery pack outside the battery pack, or a combination of the above two heating methods. Some internal heating methods use graphene heating films to wrap the battery cell inside the battery shell and generate heat after being powered on. The effect is obvious in liquid batteries, because liquid batteries only need to maintain the temperature below 40℃ during charging. If the temperature is maintained at about 80℃ for a long time, the area of the heating film is too small and the specific power of the heating film needs to be particularly high, and the voltage for maintaining heating also needs to be higher. If the existing specific power heating film is powered at 3.7 volts, it takes 54 hours to heat, that is, low-voltage power supply cannot heat the battery from a low-temperature environment of-20℃ to 40℃, and it is even more impossible to maintain the temperature of a solid-state battery at 80℃. If the specific power of the small-area heating film is increased, it is easy to cause local overheating, and the engineering implementation is difficult. A special heating film with too large an area will reduce the volume energy density and mass energy density of the battery, affecting the performance of the battery. SUMMARY

[0004] The present application aims to at least solve one of the problems in the prior art. To this end, the present application provides a self-heating battery current collector, a self-heating battery cell, a self-heating battery and a preparation method thereof.

[0005] According to the self-heating battery current collector of the first aspect of the present application, it comprises:

[0006] a substrate;

[0007] a graphene heating layer coated on the substrate;

[0008] a first conductive strip and a second conductive strip, the first conductive strip and the second conductive strip being oppositely arranged on both sides of the substrate surface and being in contact with the graphene heating layer;

[0009] an encapsulation layer covering the substrate and forming a closed interlayer with the substrate, the closed interlayer completely wrapping the first conductive strip, the second conductive strip and the graphene heating layer;

[0010] A current collector layer is coated on the outer surface of the substrate away from the graphene heating layer.

[0011] The self-heating battery current collector according to the embodiments of the present application can achieve the technical effect of a large heating sheet area under the condition of a small heating space by coating a current collector layer on the outer surface of the graphene heating layer and cooperating with the graphene heating layer to heat, so that the heating film has a small heating specific power, can heat for a long time under a low voltage and small current state, and is conducive to maintaining the optimal balanced temperature required by the solid-state battery for a long time, and is conducive to the commercialization of the solid-state battery from the laboratory.

[0012] The self-heating battery current collector according to the second aspect of the embodiments of the present application includes the self-heating battery current collector of the above-mentioned embodiments, and specifically, a current collector layer is coated on the outer surface of the packaging layer away from the graphene heating layer, so that it cooperates with the graphene heating layer to heat, can achieve the technical effect of a large heating sheet area under the condition of a small heating space, so that the heating film has a small heating specific power, can heat for a long time under a low voltage and small current state, and is conducive to maintaining the optimal balanced temperature required by the solid-state battery for a long time.

[0013] The self-heating battery current collector according to the third aspect of the embodiments of the present application includes that the outer surface of the substrate away from the graphene heating layer and the outer surface of the packaging layer away from the graphene heating layer are both coated with a current collector layer, so that it cooperates with the graphene heating layer to heat, can achieve the technical effect of a large heating sheet area under the condition of a small heating space, so that the heating film has a small heating specific power, can heat for a long time under a low voltage and small current state, and is conducive to maintaining the optimal balanced temperature required by the solid-state battery for a long time; the positive active material or the negative active material can be coated on the double-sided current collector layer at the same time, so as to reduce the use amount of the battery current collector, the separator and the solid-state electrolyte, improve the battery energy density, and reduce the battery cost.

[0014] According to some embodiments of the present application, the thickness of the current collector layer is 50-800 nm, which can ensure a small overall volume and cooperate with the graphene heating layer to maintain a good heating effect and current collection effect.

[0015] According to some embodiments of the present application, the graphene heating layer is in the form of an equal-width ladder, includes a plurality of stripe parts and edge parts distributed in parallel on both sides of the plurality of stripe parts, the interval between the plurality of stripe parts is 0-5 mm, and the thickness of the graphene heating layer is 5-500 nm, so as to achieve the effect that the overall self-heating battery current collector has a small heating specific power, can heat for a long time under a low voltage and small current state, and is conducive to maintaining the optimal balanced temperature required by the solid-state battery for a long time.

[0016] According to some embodiments of the present application, a first power supply line is connected to the first conductive strip and a second power supply line is connected to the second conductive strip, facilitating connection of an external power supply for heating.

[0017] According to the self-heating battery cell of the fourth aspect of the present application, the cell is heated by using the self-heating battery current collector as described above.

[0018] According to the self-heating battery of the fifth aspect of the present application, the battery is heated by using the self-heating battery cell as described above.

[0019] According to the self-heating battery current collector preparation method of the sixth aspect of the present application, the method comprises the following steps:

[0020] Cutting the first substrate of the self-heating battery current collector;

[0021] Weighing and metering the graphene heating material;

[0022] Pouring the weighed and metered graphene heating material into a stirring tank, starting the stirrer, and stirring at a speed of 3000-5000 revolutions per hour for 2 hours;

[0023] Reducing the stirring speed to 400-800 revolutions per hour, adding a defoaming agent, and stirring for 0.5 hours to obtain a uniform graphene heating slurry;

[0024] Pouring the uniform graphene heating slurry into a barrel for discharging;

[0025] Using a pre-installed screen printing plate to screen print the graphene heating slurry onto the first substrate to obtain a graphene heating layer, and making the graphene heating layer have an equal-width ladder shape on the first substrate;

[0026] Printing conductive strips on the edge portions on both sides of the graphene heating layer to obtain a self-heating current collector graphene heating film semi-finished product;

[0027] Covering and encapsulating the self-heating current collector graphene heating film semi-finished product with an encapsulating material to perform insulation and corrosion prevention encapsulation, and obtaining a self-heating current collector graphene heating film;

[0028] The self-heating current collector graphene heating film can be processed as follows to obtain different types of self-heating current collectors:

[0029] (a) Using the self-heating current collector graphene heating film as a second substrate, using pure aluminum as a target material, and depositing an aluminum film in a magnetron sputtering device to obtain a single-conductor layer positive electrode self-heating current collector;

[0030] (b) Using the uncoated side of the single-conductor layer positive electrode self-heating current collector as a third substrate, using pure aluminum as a target material, and depositing an aluminum film in a magnetron sputtering device to obtain a double-conductor layer positive electrode self-heating current collector;

[0031] (c) taking the self-heating current collector graphene heating film as a second substrate, pure copper as a target material, plating copper film in a magnetron sputtering device to obtain a single-face conductor layer negative electrode self-heating current collector;

[0032] (d) taking the uncoated surface of the single-face conductor layer negative electrode self-heating current collector as a third substrate, pure copper as a target material, plating copper film in a magnetron sputtering device to obtain a double-face conductor layer negative electrode self-heating current collector.

[0033] According to the self-heating battery current collector preparation method of the embodiment of the present application, the conductor layer is selectively plated on the outer surface of the uniformly prepared self-heating current collector graphene heating film semi-finished product, which cooperates with the graphene heating layer to heat, has the advantage of large heating film area under the condition of small heating space, thereby realizing the effect that the heating film has small heating specific power and can heat for a long time under the condition of low voltage and small current, which is beneficial to long-term maintenance of the optimal balanced temperature required by the solid-state battery.

[0034] Additional aspects and advantages of the present application will be made apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0036] Figure 1 is a bottom cross-sectional structure schematic diagram of a self-heating battery current collector according to the embodiment 1 of the present application;

[0037] Figure 2 is an enlarged schematic diagram of A part of Figure 1

[0038] Figure 3 is an internal structure schematic diagram of a self-heating battery current collector according to the embodiment 1 of the present application;

[0039] Figure 4 is a graphene heating layer structure schematic diagram according to the embodiment 1 or 3 of the present application;

[0040] Figure 5 is a bottom cross-sectional structure schematic diagram of a self-heating battery current collector according to the embodiment 4 of the present application;

[0041] Figure 6 is a bottom cross-sectional structure schematic diagram of a self-heating battery current collector according to the embodiment 5 of the present application;

[0042] Reference signs: ​

[0043] 100, substrate; 200, graphene heating layer; 300, first conductive strip; 400, second conductive strip; 500, first power supply line; 600, second power supply line; 700, encapsulation layer; 800, current collector layer;

[0044] 210, edge portion; 220, stripe portion. DETAILED DESCRIPTION

[0045] The embodiments of the present application are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely exemplary and are used to explain the present application, but are not intended to limit the present application.

[0046] Embodiment 1

[0047] Reference Figures 1-3 As shown, the self-heating battery current collector according to the first embodiment of the present application comprises:

[0048] Substrate (5-7um thick ultra-thin polyimide PI or polyester resin PET) 100;

[0049] Graphene heating layer 200 coated on the substrate 100;

[0050] First conductive strip 300 and second conductive strip 400, the first conductive strip 300 and the second conductive strip 400 are oppositely arranged on both sides of the surface of the substrate 100 and in contact with the graphene heating layer 200;

[0051] Encapsulation layer 700 covering the substrate 100, forming an enclosed interlayer with the substrate 100, the enclosed interlayer completely wrapping the first conductive strip 300, the second conductive strip 400 and the graphene heating layer 200; for encapsulating the graphene heating layer 200, the first conductive strip 300 and the second conductive strip 400;

[0052] Current collector layer 800 coated on the outer surface of the substrate 100 away from the graphene heating layer 200.

[0053] The self-heating battery current collector according to the embodiment of the present application has a total thickness of 11-15um, which is comparable to the thickness of the commonly used aluminum current collector, and the mass is about 1.2mg / cm 2 , which is only about one-third of the commonly used aluminum current collector, which is beneficial to improve the mass energy density of the battery. By coating the current collector layer on the outer surface of the substrate 100 of the graphene heating layer 200, and cooperating with the graphene heating layer 200 to heat, it can achieve the technical effect of large heating film area under the condition of small heating space, so that the heating film has small heating specific power, and can heat for a long time under low voltage and small current, which is beneficial to maintain the optimal balanced temperature required by the solid-state battery for a long time.

[0054] Specifically, the first conductive band 300 is connected with a first power supply line 500, and the second conductive band 400 is connected with a second power supply line 600, so as to facilitate connection of external power supply for heating.

[0055] Specifically, the encapsulation layer 700 is 5-7um thick ultra-thin polyimide PI.

[0056] Specifically, the encapsulation layer 700 is 5-7um thick polyester resin PET.

[0057] Embodiment 2

[0058] On the basis of embodiment 1, the current collector layer 800 has a thickness of 50-800nm, which, in the case of ensuring small overall volume, cooperates with the graphene heating layer to maintain a better heating effect and current collecting effect.

[0059] Embodiment 3

[0060] On the basis of embodiment 1, the graphene heating layer 200 has an equal-width ladder shape, and includes a plurality of stripe portions 220 and edge portions 210 distributed in parallel on both sides of the plurality of stripe portions 220. The plurality of stripe portions 220 are spaced apart by a range of 0-5mm, and the graphene heating layer 200 has a thickness of 5-500nm, so as to satisfy the condition that the overall self-heating battery current collector has a small heating film heating specific power, can heat for a long time under low voltage and small current, and is conducive to long-term maintenance of the optimal balanced temperature required by the solid-state battery.

[0061] Embodiment 4

[0062] The self-heating battery current collector includes the part of embodiment 1, and specifically, the current collector layer 800 is coated on the outer surface of the encapsulation layer 700 away from the graphene heating layer 200, so as to cooperate with the graphene heating layer 200 for heating, so that it can achieve the technical effect of a large heating sheet area under the condition of small heating space, can heat for a long time under low voltage and small current, and is conducive to long-term maintenance of the optimal balanced temperature required by the solid-state battery.

[0063] Embodiment 5

[0064] The self-heating battery current collector of the above embodiment 1 is coated with a current collector layer 800 on the outer surface of the substrate 100 away from the graphene heating layer 200 and on the outer surface of the packaging layer 700 away from the graphene heating layer 200, which cooperates with the graphene heating layer 200 to heat, so that it can achieve the technical effect of a large heating sheet area under the condition of a small heating space, and the heating film has a small specific power, can heat for a long time under low voltage and small current, is conducive to maintaining the optimal balanced temperature required by the solid-state battery for a long time, and can coat positive active material or negative active material on the double-sided current collector layer to reduce the use amount of battery current collector, separator and solid-state electrolyte, improve the energy density of the battery, and reduce the cost of the battery.

[0065] Embodiment 6

[0066] The present embodiment provides a self-heating solid-state battery, which includes heating the interior of the solid-state battery by using the above self-heating battery current collector.

[0067] Embodiment 7

[0068] The present embodiment provides a self-heating liquid battery, which includes heating the interior of the liquid battery by using the above self-heating battery current collector, which can completely change the problem of capacity shrinkage of the battery at low temperature, improve the charging speed, service life and safety performance of the liquid battery.

[0069] Embodiment 8

[0070] The present embodiment provides a preparation method of a positive electrode self-heating current collector, which includes:

[0071] Cutting the first substrate of the self-heating battery current collector;

[0072] Weighing and metering the graphene electrothermal material, specifically including: 33 parts of water-based graphene filter cake, 0-33 parts of water-based carbon nanotube, 0-10 parts of pure water, and 67 parts of water-based modified resin;

[0073] Pour the weighed and metered graphene electrothermal material into the stirring tank, start the stirrer, and stir at a speed of 3000-5000 revolutions per hour for 2 hours;

[0074] Reduce the speed of the stirrer to 400-800 revolutions per hour, add 0.5 parts of defoaming agent, and stir at low speed for 0.5 hours to obtain uniform graphene electrothermal slurry;

[0075] Pack the uniform graphene electrothermal slurry and discharge it;

[0076] The graphene heating layer is obtained by screen printing graphene electric heating paste on the first substrate using a pre-installed screen or intaglio printing plate, and the graphene heating layer is in the form of an equal-width ladder on the first substrate, with thin stripes in the middle and thick stripes on both sides, and the thick and thin stripes are connected to form a zebra stripe mesh structure, and the printing layer thickness of the graphene heating layer is 5-500 nm. The width and interval of the thin stripes are determined according to the self-heating current collector heating specific power, the line width of the thin stripes is 4 mm, and the interval is 2-3 mm, and the line width of the thick stripes is 10 mm;

[0077] A conductive strip is printed on the edge part on both sides of the graphene heating layer, the width of the conductive strip is 9 mm, the printing layer thickness of the conductive strip is 50-900 nm, and a self-heating current collector graphene heating film semi-finished product is obtained;

[0078] The self-heating current collector graphene heating film semi-finished product is covered and packaged with a packaging material (PI or PET) with a thickness of 5-7 um, and insulation and corrosion prevention packaging is performed to obtain a self-heating current collector graphene heating film;

[0079] The self-heating current collector graphene heating film is processed as follows to obtain single-sided and double-sided self-heating current collectors:

[0080] (a) The self-heating current collector graphene heating film is used as a second substrate, and pure aluminum is used as a target material to plate an aluminum film in a magnetron sputtering device to obtain a single-sided conductor layer positive electrode self-heating current collector;

[0081] (b) The uncoated surface of the single-sided conductor layer positive electrode self-heating current collector is used as a third substrate, and pure aluminum is used as a target material to plate an aluminum film in a magnetron sputtering device to obtain a double-sided conductor layer positive electrode self-heating current collector.

[0082] Example 9

[0083] The embodiment provides a preparation method of a negative electrode self-heating current collector, and the method comprises the following steps:

[0084] The first substrate of the self-heating battery current collector is cut;

[0085] The graphene electric heating material is weighed and measured, and specifically includes: 33 parts of water-based graphene filter cake, 0-33 parts of water-based carbon nanotubes, 0-10 parts of pure water, and 67 parts of water-based modified resin;

[0086] The weighed and measured graphene electric heating material is poured into a stirring tank, and a stirrer is started at a stirring speed of 3000-5000 revolutions per hour, and stirring is performed for 2 hours;

[0087] The stirring speed of the stirrer is reduced to 400-800 revolutions per hour, 0.5 parts of a defoaming agent is added, and low-speed stirring is performed for 0.5 hours to obtain uniform graphene electric heating paste;

[0088] The uniform graphene electric heating paste is loaded into a barrel and discharged;

[0089] The graphene heating layer is obtained by screen printing graphene electric heating paste on the first substrate by using a preset screen or intaglio printing plate, and the graphene heating layer is arranged in a ladder shape with equal width on the first substrate, the middle part is a thin stripe, the two sides are thick stripes, and the thick and thin stripes are connected to form a zebra stripe net structure, and the printing thickness of the graphene heating layer is 5-100 nm.

[0090] The conductive strips are printed on the edge parts on the two sides of the graphene heating layer, the width of the conductive strips is 9 mm, the printing thickness of the conductive strips is 500-900 nm, and a self-heating current collector graphene heating film semi-finished product is obtained.

[0091] The self-heating current collector graphene heating film semi-finished product is covered and encapsulated by a material (PI or PET) with a thickness of 5-7 um, and is encapsulated for insulation and corrosion prevention to obtain a self-heating current collector graphene heating film.

[0092] The self-heating current collector graphene heating film is processed as follows to obtain two types of self-heating current collectors, namely single-sided and double-sided self-heating current collectors.

[0093] (c) The self-heating current collector graphene heating film is used as the second substrate, and pure copper is used as the target material to plate a copper film in a magnetron sputtering device to obtain a single-sided conductor layer negative self-heating current collector.

[0094] (d) The surface of the single-sided conductor layer negative self-heating current collector without plating is used as the third substrate, and pure copper is used as the target material to plate a copper film in a magnetron sputtering device to obtain a double-sided conductor layer negative self-heating current collector.

[0095] Example 10

[0096] In this embodiment, the thickness of the plated aluminum film is selected to be 50-800 nm on the basis of Example 9, and the thickness of the plated copper film is selected to be 50-800 nm on the basis of Example 10 to ensure the current collecting effect.

[0097] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms “center”, “longitudinal”, “transverse”, “length”, “width”, “thickness”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential” and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0098] In the description of the application, references to "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" mean that a particular feature, structure, material, or characteristic being described is included in at least one embodiment or example of the application. The appearances of the phrases "in one embodiment", "in some embodiments", "in an example", "in a specific example", or "in some examples" in various places in the specification are not necessarily all referring to the same embodiment or example.

[0099] It is apparent that the described embodiments are only some, but not all, of the embodiments of the present application. Reference to "an embodiment" or "some embodiments" in this specification means that a particular feature, structure, material or characteristic described in connection with the embodiment is included in at least one embodiment or example of the application. The appearances of the phrase "in one embodiment" or "in some embodiments" in various places in the specification are not necessarily all referring to the same embodiment or example, nor are they necessarily mutually exclusive or alternative embodiments or examples. It will be apparent to those skilled in the art from this disclosure that the described embodiments can be combined with other embodiments in a manner not specifically mentioned in the above description. All such possible combinations are within the scope of the present application.

[0100] Although the embodiments of the present application have been shown and described, it will be apparent to those skilled in the art that certain changes, modifications, substitutions and alterations can be made thereto without departing from the principles and the spirit of the application, the scope of which is defined by the claims and their equivalents.

Claims

1. A self-heating battery current collector, characterized by, It comprises: a substrate (100); a graphene heating layer (200) coated on the substrate (100), the graphene heating layer (200) is in the form of equal-width ladder, comprising a plurality of stripe parts (220) and edge parts (210) distributed on both sides of the plurality of stripe parts (220), the interval between the stripe parts (220) is 0-5mm, and the thickness of the graphene heating layer (200) is 5-500nm; a first conductive strip (300) and a second conductive strip (400), the first conductive strip (300) and the second conductive strip (400) are oppositely arranged on both sides of the surface of the substrate (100) and are in contact with the graphene heating layer (200); an encapsulation layer (700) covering the substrate (100) and forming a closed interlayer with the substrate (100), the closed interlayer completely wraps the first conductive strip (300), the second conductive strip (400) and the graphene heating layer (200); a current collector layer (800) coated on the outer surface of the substrate (100) away from the graphene heating layer (200).

2. A self-heating battery current collector according to claim 1, wherein A current collector layer (800) is coated on the outer surface of the encapsulation layer (700) away from the graphene heating layer (200).

3. A self-heating battery current collector according to claim 1, wherein The outer surface of the substrate (100) away from the graphene heating layer (200) and the outer surface of the encapsulation layer (700) away from the graphene heating layer (200) are both coated with a current collector layer (800).

4. A self-heating battery current collector according to any one of claims 1 to 3, wherein The thickness of the current collector layer (800) is 50-800nm.

5. A self-heat electric core, characterized by, It comprises heating an electric cell by using the self-heating battery current collector according to any one of claims 1-4.

6. A self-heat battery, characterized by It comprises heating the inside of a battery by using the self-heating cell according to claim 5.

7. A method of making a self-heating battery current collector, the method comprising: It comprises: cutting a first substrate of a self-heating battery current collector; weighing and metering graphene heating material; pouring the weighed and metered graphene heating material into a stirring tank, starting the stirrer, and stirring at a speed of 3000-5000 revolutions per hour for 2 hours; reducing the stirring speed to 400-800 revolutions per hour, adding a defoaming agent, and stirring for 0.5 hours to obtain uniform graphene heating slurry; filling the uniform graphene heating slurry into a barrel for discharging; screen printing the graphene heating slurry onto the first substrate using a pre-set screen printing plate to obtain a graphene heating layer, and making the graphene heating layer in the form of equal-width ladder on the first substrate; printing a conductive strip on the edge part on both sides of the graphene heating layer to obtain a self-heating current collector graphene heating film semi-finished product; covering the self-heating current collector graphene heating film semi-finished product with an encapsulation material to perform insulation and corrosion prevention encapsulation to obtain a self-heating current collector graphene heating film; processing the self-heating current collector graphene heating film as follows to obtain different types of self-heating current collectors: (a) taking the self-heating current collector graphene heating film as a second substrate, using pure aluminum as target material, and plating an aluminum film in a magnetron sputtering device to obtain a single-face conductor layer positive electrode self-heating current collector; (b) taking the uncoated side of the single-face conductor layer positive electrode self-heating current collector as a third substrate, using pure aluminum as target material, and plating an aluminum film in a magnetron sputtering device to obtain a double-face conductor layer positive electrode self-heating current collector; (c) The self-heating current collector graphene heating film is used as the second substrate, and pure copper is used as the target material to plate copper film in a magnetron sputtering device, so as to obtain a single-face conductor layer negative electrode self-heating current collector; (d) The surface of the single-face conductor layer negative electrode self-heating current collector which is not plated with film is used as the third substrate, and pure copper is used as the target material to plate copper film in a magnetron sputtering device, so as to obtain a double-face conductor layer negative electrode self-heating current collector.

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