Electrode sheet and preparation method therefor, and battery and electric system

Abstract

Provided are an electrode sheet and a preparation method therefor, and a battery and an electric system. The electrode sheet comprises a current collector and an active material layer, which are stacked, wherein the active material layer comprises a plurality of active particles, and the active material layer further has a first pore and a second pore; and the pore diameter R1 of the first pore and the pore diameter R2 of the second pore satisfy: 0.05*D50≤R1<0.65*D50 and 0.65*D50≤R1≤10*D50, D50 being the median particle diameter of the plurality of active particles, and the units of R1 and R2 being nm.

Description

Pole piece and preparation method thereof, battery and power system

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on October 31, 2023, with application number 202311438729.2 and application name “Electrode and its preparation method, battery and power system”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of lithium battery technology, and in particular to a pole piece and a preparation method thereof, a battery and a power system. Background Art

[0003] In secondary batteries, the wettability of the electrolyte has a crucial impact on battery performance. If the electrolyte does not wet the positive and negative electrodes of the battery well, it will affect the transmission of ions and the conduction of electrons, thereby reducing the ion mobility of the battery. When the electrolyte wettability is poor, the ion transmission rate inside the battery will be greatly reduced. This will not only affect the charge and discharge rate of the battery, but will also cause the battery to generate a large internal resistance during the charge and discharge process, reducing the energy efficiency of the battery. In addition, if the electrolyte wettability is insufficient, it may also cause the battery to experience capacity attenuation, electrode material corrosion and other problems during the charge and discharge process. The emergence of these problems will further shorten the service life of the battery, so how to improve the wettability of the electrolyte to improve the performance of secondary batteries has become the key.

[0004] Summary of the Invention

[0005] The purpose of this application is to provide a pole piece and its preparation method, a battery and a power system to solve the problems of poor electrolyte wettability and low ion mobility.

[0006] To achieve the purpose of this application, this application provides the following technical solutions:

[0007] In a first aspect, the present application provides a pole piece comprising a current collector and an active material layer arranged in a stacked manner; the active material layer comprises a plurality of active particles, and the active material layer further has a first pore and a second pore; the pore size R1 of the first pore and the pore size R2 of the second pore satisfy: 0.05*D50≤R1<0.65*D50, 0.65*D50≤R1≤10*D50, wherein D50 is the median particle size of the plurality of active particles, and the units of R1 and R2 are nm.

[0008] In one embodiment, the porosity A1 of the first pores satisfies: 15%≤A1≤34.5%; the porosity A2 of the second pores satisfies: 0.3%≤A2≤10%.

[0009] In one embodiment, the total porosity in the active material layer is σ, the total porosity σ includes the porosity A1 of the first pores and the porosity A2 of the second pores, and the total porosity σ satisfies: 25%≤σ≤35%, and A1+A2≤σ.

[0010] In one embodiment, the ratio η of the porosity A2 of the second pore to the porosity A1 of the first pore is A2 / A1, satisfying: 1%*(σ / A)≤η≤15%*(σ / A), wherein A is a correction coefficient of the total porosity σ of the active material layer, and A satisfies: 25%≤A≤35%.

[0011] In one embodiment, a ratio η of the porosity A2 of the second pores to the porosity A1 of the first pores is A2 / A1, which satisfies: 1%*(σ / 30%)≤η≤15%*(σ / 30%).

[0012] In one embodiment, a ratio η of the porosity A2 of the second pores to the porosity A1 of the first pores is A2 / A1, which satisfies: 1%≤η≤15%.

[0013] In one embodiment, the active material layer includes a first surface and a second surface opposite to each other, the first surface is connected to the current collector; along the direction from the first surface to the second surface, the proportion of the second pores tends to first decrease and then increase.

[0014] In one embodiment, the median particle size D50 of the active particles satisfies: 100 nm ≤ D50 ≤ 30 μm.

[0015] In the second aspect, the present application provides a method for manufacturing an electrode, comprising: preparing a mixed powder containing an active material; preparing an active material layer using the mixed powder, and disposing the active material layer on a current collector; the active material layer comprises a plurality of active particles, and the active material layer further has a first pore and a second pore; the pore size R1 of the first pore and the pore size R2 of the second pore satisfy: 0.05*D50≤R1<0.65*D50, 0.65*D50≤R1≤10*D50, wherein D50 is the median particle size of the active particles.

[0016] In one embodiment, preparing a mixed powder containing active materials includes: pre-mixing the active material, a binder and a conductive agent in proportion to obtain a pre-mixed powder; putting the pre-mixed powder into a jet mill for grinding and mixing to obtain a jet mill mixed powder.

[0017] In one embodiment, the mass percentage of the binder is 1.5% to 5%, the mass percentage of the conductive agent is 0.3% to 2%, and the premixed powder is put into a jet mill for grinding and mixing at a crushing pressure range of 0.1 MPa to 0.8 MPa.

[0018] In one embodiment, the active material layer is prepared using the mixed powder and the active material layer is disposed on the current collector, including: rolling the air flow milled mixed powder to form a first self-supporting membrane; rolling the first self-supporting membrane to form a second self-supporting membrane; and bonding the second self-supporting membrane to the current collector to obtain the pole piece.

[0019] In one embodiment, the rolling line pressure range for forming the first self-supporting film is 0.1t / cm~1t / cm, the differential ratio satisfies 1:1~1:3, and the temperature range is 100℃~250℃; the calendering line pressure range for forming the second self-supporting film is 0.1t / cm~1t / cm, the differential ratio satisfies 1:1~1:3, and the temperature range is 60℃~180℃; the calendering line pressure range for bonding the second self-supporting film to the current collector to obtain the electrode is 0.1t / cm~1t / cm, and the differential ratio satisfies 1:1~1:3.

[0020] In a third aspect, the present application provides a battery comprising a separator and an electrode sheet as described in the above embodiment, wherein the electrode sheet comprises a positive electrode sheet and a negative electrode sheet, the positive electrode sheet and the negative electrode sheet being respectively disposed on opposite sides of the separator. The electrode sheet comprises the electrode sheet according to any embodiment of the first aspect of the present application, or the electrode sheet produced by the electrode sheet production method according to any embodiment of the second aspect of the present application.

[0021] In a fourth aspect, the present application provides an electricity system, which includes an electric device and a battery as described in the above embodiment, and the battery is used to supply power to the electric device.

[0022] In the present application, the active material layer in the electrode is provided with a first pore and a second pore, and the pore sizes of the first pore and the second pore meet a specific range. The larger second pore becomes a large high-speed channel with high-flux ion migration, and the smaller first pore becomes a dense capillary channel. The pore distribution structure with matching sizes is used to improve the wettability of the electrolyte in the active material, thereby optimizing the migration path of ions inside the electrode, reducing the overall internal resistance of the battery, and further improving the power performance, fast charging performance and low-temperature performance of the electrode on the basis of improving the ion mobility. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the implementation methods or the description of the prior art. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] FIG1 is a schematic longitudinal cross-sectional view of a pole piece according to an embodiment;

[0025] FIG2 is a schematic transverse cross-sectional view of a pole piece according to an embodiment;

[0026] FIG3 is a schematic longitudinal cross-sectional view of an active material layer according to an embodiment;

[0027] FIG4 is a flow chart of a method for preparing a pole piece according to an embodiment;

[0028] FIG5 is a pore size distribution diagram of Example 1 and Comparative Example 1;

[0029] FIG6 is a schematic structural diagram of a battery in one embodiment;

[0030] FIG7 is a schematic structural diagram of an electric power system according to an embodiment.

[0031] Explanation of the accompanying numbers: 100-pole piece, 10-active material layer, 11-first pore, 12-second pore, 13-active particles, 10A-first surface layer, 10B-second surface layer, 10C-intermediate layer, 101-first surface, 102-second surface, 20-current collector, 1000-battery, 200-diaphragm, 300-electrolyte, 2000-power system, 3000-power equipment. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0033] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may be an intermediate component. When a component is referred to as being "connected to" another component, it may be directly connected to the other component or there may be an intermediate component.

[0034] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art to which this application belongs. The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used in this application includes any and all combinations of one or more of the relevant listed items.

[0035] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features therein may be combined with each other.

[0036] The present application provides a pole piece 100, please refer to Figure 1, including a stacked current collector 20 and an active material layer 10; the active material layer 10 includes a plurality of active particles 13, and the active material layer 10 also has a first pore 11 and a second pore 12; the pore size R1 of the first pore 11 and the pore size R2 of the second pore 12 satisfy: 0.05*D50≤R1<0.65*D50, 0.65*D50≤R1≤10*D50, wherein D50 is the median particle size of the plurality of active particles 13, and the units of R1 and R2 are nm.

[0037] Specifically, the electrode sheet 100 may be a positive electrode sheet or a negative electrode sheet. The electrode active material in the positive electrode sheet is the positive electrode active particles, and the electrode active material in the negative electrode sheet is the negative electrode active particles.

[0038] Optionally, the current collector 20 may be a foam metal mesh, a metal film material, etc., specifically including any one of copper foil and aluminum foil.

[0039] Optionally, when the electrode 100 is a positive electrode, the types of positive electrode active particles include lithium embedded active particles, sodium embedded active particles, potassium embedded active particles, magnesium embedded active particles, zinc embedded active particles, and aluminum embedded active particles. Taking lithium secondary batteries as an example, the positive electrode active particles are selected from LiCoO2, LiNiO2, LiCo x Ni 1-x O2(0≤x≤1), LiCo x Ni 1-x-y Al y O2(0≤x≤1,0≤y≤1), LiMn2O4, LiFe x Mn y M z O4 (M is at least one of Al, Mg, Ga, Cr, Co, Ni, Cu, Zn or Mo, 0≤x≤1, 0≤y≤1, 0≤z≤1, x+y+z=1), Li 1+x L 1－y－z M y N zO2 (L, M, N is at least one of Li, Co, Mn, Ni, Fe, Al, Mg, Ga, Ti, Cr, Cu, Zn, Mo, F, I, S, B, -0.1≤x≤0.2, 0≤y≤1, 0≤z≤1, 0≤y+z≤1), LiFePO4, Li3V2(PO4)3, Li3V3(PO4)3, LiVPO4F, Li2CuO2, Li5FeO4, and metal sulfides and oxides such as TiS2, V2S3, FeS, FeS2, LiMS x (M is at least one transition metal element such as Ti, Fe, Ni, Cu, Mo, 1≤x≤2.5), at least one of the group consisting of TiO2, Cr3O8, V2O5, MnO2, etc.

[0040] Optionally, when the electrode sheet 100 is a negative electrode, the negative electrode may include one or more of a carbon-based negative electrode, a silicon-based negative electrode, a tin-based negative electrode, a lithium negative electrode, a sodium negative electrode, a potassium negative electrode, a magnesium negative electrode, a zinc negative electrode, and an aluminum negative electrode. Carbon-based negative electrodes may include graphite, hard carbon, soft carbon, etc.; silicon-based negative electrodes may include silicon, silicon-carbon, silicon-oxygen, silicon-metal compounds, etc.; tin-based negative electrodes may include tin, tin-carbon, tin-oxygen, and tin-metal compounds; and lithium negative electrodes may include metallic lithium or a lithium alloy. Specifically, the lithium alloy may include at least one of a lithium-silicon alloy, a lithium-sodium alloy, a lithium-potassium alloy, a lithium-aluminum alloy, a lithium-tin alloy, and a lithium-indium alloy.

[0041] Optionally, when the electrode 100 is a negative electrode, the negative electrode active particles include one or more of natural graphite, artificial graphite, hard carbon, soft carbon, lithium titanate, iron oxide, lithium titanium phosphate, titanium dioxide, silicon, silicon oxide, aluminum, tin and antimony.

[0042] Optionally, the active material layer 10 also includes an adhesive, which includes one or more of tetrafluoroethylene and its copolymers, polyvinylidene fluoride and its copolymers, polyolefins and their copolymers, polyethers and their copolymers, polyphenylene ethers and their copolymers, polysiloxanes and their copolymers, polyesters and their copolymers, polyethylene oxide, polyethylene-polyethylene glycol block copolymers, polydimethylsiloxane, poly(dimethylsiloxane-co-alkylmethylsiloxane), nitrile rubber, polyvinyl ester, polyvinyl acetate, and polyacrylate.

[0043] Optionally, the polyolefin includes one or more of polyethylene, polypropylene, ethylene / propylene copolymer, ethylene / vinylidene fluoride copolymer, and propylene / vinylidene fluoride copolymer; polytetrafluoroethylene and its copolymers can be one or more of tetrafluoroethylene / ethylene copolymer, tetrafluoroethylene / propylene copolymer, tetrafluoroethylene / vinylidene fluoride copolymer, tetrafluoroethylene / ether copolymer, tetrafluoroethylene / silicone copolymer, tetrafluoroethylene / branched polyether copolymer, tetrafluoroethylene / vinyl ether copolymer, and tetrafluoroethylene / branched polyether / vinyl ether copolymer.

[0044] Optionally, the active material layer 10 further includes a conductive agent, which may be one or more of conductive carbon black, acetylene black, Ketjen black, conductive graphite, carbon nanotubes, carbon fibers, and graphene.

[0045] Alternatively, the active material layer 10 may be a self-supporting membrane. The self-supporting membrane may be prepared using a dry electrode process, using a polymer as the adhesive, and the polymer may have a low bulk density. A polymer with a low bulk density is more likely to form a fluffy state, allowing a self-supporting membrane of suitable thickness to be obtained after a single hot pressing step. The adhesive may be processed into a fibrous state by shearing, and the fibrous adhesive may be mixed with the active particles 13 and then hot pressed to form a self-supporting membrane.

[0046] Furthermore, the active material layer 10 also has pores, including a first pore 11 and a second pore 12. The first pore 11 and the second pore 12 have different pore diameters, with the second pore 12 having a larger diameter than the first pore 11. It should be noted that, as shown in FIG1 , in a longitudinal cross-section of the active material layer 10, the first pore 11 and the second pore 12 may have irregular contours, and the pore diameters of the first pore 11 and the second pore 12 are the distance between the two closest points on their contours. Alternatively, the pore diameters of the first pore 11 and the second pore 12 may be the distance between the two farthest points on their contours. It is understood that when the pore diameter of the first pore 11 is the distance between the two closest points on its contour, the same measurement method should be used for the second pore 12. A scanning electron microscope (SEM) photograph of a longitudinal cross-section of the active material layer 10 at a magnification of 5000x was obtained. A 0.5 cm by 0.5 cm area was selected from the SEM photograph, and the distance of the irregular contour within that area was measured. The aperture of the first pore 11 and the aperture of the second pore 12 can also be obtained by testing the aperture distribution curve of the pole piece.

[0047] The pore size R1 of the first pore 11 satisfies the following: 0.05*D50 ≤ R1 < 0.65*D50; the pore size R2 of the second pore 12 satisfies the following: 0.65*D50 ≤ R1 ≤ 10*D50. D50 is the median particle size of the active particles 13, i.e., the average particle size of the active particles 13. Therefore, in different pole pieces 100, the pore sizes of the first and second pores 11, 12 depend on the particle size of the active particles 13 used.

[0048] The D50 can be obtained by measuring the particle size cross-section of multiple active particles 13 on a longitudinal cross-section of the active material layer 10 using a scanning electron microscope, and then measuring the particle size distribution using ImageJ software. Specifically, a 5000x magnification SEM photograph of the longitudinal cross-section of the active material layer 10 is obtained using a scanning electron microscope. An area with a length and width of 0.5 cm by 0.5 cm is selected from the SEM photograph, and the particle size of multiple active particles 13 in this area is measured. The particle size distribution is then measured using ImageJ software to obtain the D50. On the longitudinal cross-section of the active material layer 10, the active particles 13 have different profiles. The particle size of a single active particle 13 is obtained by taking the two closest points on each particle profile.

[0049] Optionally, the pore size R1 of the first pore 11 may be, but is not limited to, 0.05*D50, 0.15*D50, 0.2*D50, 0.25*D50, 0.3*D50, 0.35*D50, 0.4*D50, 0.45*D50, 0.5*D50, 0.55*D50, or 0.64*D50. The pore size R2 of the second pore 12 may be, but is not limited to, 0.65*D50, 1*D50, 2*D50, 3*D50, 4*D50, 5*D50, 6*D50, 7*D50, 8*D50, 9*D50, or 10*D50. The units of R1 and R2 are nm.

[0050] It can be understood that the first pore 11 and the second pore 12 are channels in the active material layer 10 for the electrolyte to invade and carry ions to flow. As shown in Figure 2, on the cross section of the electrode 100, the first pore 11 and the second pore 12 can be bent and extended in any direction (indicated by the dotted line in Figure 2). When the pore diameters of the first pore 11 and the second pore 12 are different, the flow rate of the electrolyte flowing through the first pore 11 and the flow rate of the electrolyte flowing through the second pore 12 are different. Specifically, the flow rate of the electrolyte in the second pore 12 should be greater than the flow rate of the electrolyte in the first pore 11.

[0051] Optionally, within a unit volume of the active material layer 10, the first pores 11 and the second pores 12 are uniformly distributed; that is, within a unit volume of the active material layer 10, the ratio of the proportion (porosity) of the first pores 11 to the proportion (porosity) of the second pores 12 satisfies a certain range. For example, within a unit volume of the active material layer 10, the porosity of the first pores 11 is A1, the porosity of the second pores 12 is A2, and A2 / A1 = η, where η is a constant.

[0052] Therefore, in the active material layer 10, when the pore size of the first pore 11 is smaller than that of the second pore 12, the second pore 12 is a large high-speed channel with high-flux ion migration in the active material layer 10, and the first pore 11 is densely distributed in the active material layer 10 similar to capillary channels, thereby ensuring that ions penetrate into each active particle 13.

[0053] In the present application, the active material layer 10 in the electrode 100 has a first pore 11 and a second pore 12, and the pore sizes of the first pore 11 and the second pore 12 meet a specific range. The larger second pore 12 becomes a large high-speed channel with high-flux ion migration, and the smaller first pore 11 becomes a dense capillary channel. The pore distribution structure with matching sizes is used to improve the wettability of the electrolyte in the active material, thereby optimizing the migration path of ions inside the electrode 100, reducing the overall internal resistance of the battery, and further improving the power performance, fast charging performance and low-temperature performance of the electrode 100 on the basis of improving the ion mobility.

[0054] In one embodiment, the total porosity in the active material layer 10 is σ, which includes the porosity A1 of the first pores 11 and the porosity A2 of the second pores 12 . The total porosity σ satisfies: 25%≤σ≤35%, and A1+A2≤σ.

[0055] Specifically, the total porosity in the active material layer 10 is the space within the active material layer 10 that satisfies the requirements for electrolyte infiltration and ion migration after the electrode sheet 100 is formed. The total porosity σ in the active material layer 10 is related to the particle size distribution of the active particles 13. A wider particle size distribution of the active particles 13 results in higher tap density and compaction density of the active material layer 10, resulting in a lower total porosity σ in the active material layer 10. Conversely, a narrower particle size distribution of the active particles 13 results in lower tap density and compaction density of the active material layer 10, resulting in a higher total porosity σ in the active material layer 10.

[0056] Optionally, the active material layer 10 may further include a third pore, and the pore size of the third pore may be smaller than that of the first pore 11. Therefore, it can be understood that the total porosity σ in the active material layer 10 is the sum of the porosity A1 of the first pore 11 and the porosity A2 of the second pore 12 (when the third pore is present, the porosity A3 of the third pore is also included).

[0057] Optionally, σ may be, but is not limited to, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, or 35%.

[0058] By setting the total porosity σ in the active material layer 10 within the above range, the contact between the active particles 13 and the electrolyte can be improved, thereby increasing the utilization rate of the active material; and the appropriate porosity structure can provide the battery with appropriate mechanical strength and thermal stability, thereby increasing the service life and safety of the battery.

[0059] In one embodiment, the porosity A1 of the first pores 11 satisfies: 15%≤A1≤34.5%; and the porosity A2 of the second pores 12 satisfies: 0.3%≤A2≤10%.

[0060] Specifically, based on the total porosity σ provided in the above embodiment, the porosity A1 of the first pores 11 and the porosity A2 of the second pores 12 are further controlled so that the porosity A1 of the first pores 11 is greater than the porosity A2 of the second pores 12. The advantage of this arrangement is that the first pores 11 have a larger proportion, thereby ensuring that ions penetrate into the capillary channels between the active particles 13 and exchange ions with the active particles 13.

[0061] Optionally, the porosity A1 of the first pore 11 may be, but is not limited to, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, or 34.5%.

[0062] Optionally, the porosity A2 of the second pores 12 may be, but is not limited to, 0.3%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%.

[0063] In one embodiment, the ratio η of the porosity A2 of the second pores 12 to the porosity A1 of the first pores 11 is A2 / A1, satisfying: 1%*(σ / A)≤η≤15%*(σ / A), where A is the correction coefficient of the total porosity σ of the active material layer 10, and A satisfies: 25%≤A≤35%.

[0064] Specifically, in the above relationship, A is the correction coefficient of the total porosity σ in the active material layer 10, that is, on the basis of the electrode 100 provided by the present application, the coefficient used to correct the total porosity σ so that the distribution reliability of the proportion of the porosity A1 of the first pore and the porosity A2 of the second pore is higher.

[0065] It is understandable that in actual production, the total porosity σ of each electrode piece 100 is not a fixed value. Due to the error in the manufacturing process, the total porosity σ of each electrode piece 100 should be within a range and can present a normal distribution. The A given in the present invention is the median of the total porosity σ of the electrode piece 100. For example, the total porosity σ of the electrode piece 100 needs to be 30%, but the actual total porosity σ of each electrode piece 100 should be close to 30%, so a correction factor A of 30% can be added, and (σ / A) is the final correction factor close to 1, so that A2 / A1 in each electrode piece 100 has high reliability.

[0066] Optionally, the correction coefficient A of the total porosity σ may be, but is not limited to, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, or 35%.

[0067] Because the active material layer 10 includes multiple active particles 13, the performance of the electrode sheet 100 can be optimized by controlling the particle size distribution of the active particles 13 and the pore sizes of the first pores 11 and the second pores 12. For example, by controlling the range of pore sizes R1 and R2, the porosity, permeability, and ion transport rate of the active material layer 10, as well as the electrode's capacity and internal resistance, can be adjusted. Furthermore, using the aforementioned relationship, the pore size ranges of the two pores in the active material layer 10 can be further customized, and the pore size can be adjusted according to the needs of specific applications to optimize battery performance.

[0068] In one embodiment, the ratio η of the porosity A2 of the second pores 12 to the porosity A1 of the first pores 11 is A2 / A1, which satisfies: 1%*(σ / 30%)≤η≤15%*(σ / 30%).

[0069] Specifically, the total porosity σ in the obtained active material layer 10 is approximately 30%. Therefore, when 30% is set as the correction coefficient A for the total porosity σ in the active material layer 10, the total porosity σ in the active material layer 10 is the actual measured total porosity of the manufactured electrode 100. The ratio of the two (σ / 30%) can be understood as a correction to the ratio η of the second pore 12 to the first pore 11.

[0070] In one embodiment, the ratio η of the porosity A2 of the second pores 12 to the porosity A1 of the first pores 11 is A2 / A1, which satisfies: 1%≤η≤15%.

[0071] Optionally, when σ is equal to 30% and A is equal to 30%, the ratio η of the second pore 12 to the first pore 11 can be, but is not limited to, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15%.

[0072] In one embodiment, referring to FIG3 , the active material layer 10 includes a first surface 101 and a second surface 102 facing each other, and the first surface 101 is connected to the current collector 20 . In the direction from the first surface 101 to the second surface 102 , the proportion of the second pores 12 decreases first and then increases.

[0073] Specifically, the pole piece 100 provided in the present application has a differentiated pore distribution structure in which the proportion of the second pores 12 in the surface layer increases as the electrode piece 10 is closer to the active material layer 10 .

[0074] As shown in FIG3 , the active material layer 10 includes a first surface 101 and a second surface 102 facing each other. The active material layer 10 can be divided into a first surface layer 10A, a second surface layer 10B, and an intermediate layer 10C (demarcation indicated by a dotted line in FIG3 ), wherein the intermediate layer 10C is located between the first surface layer 10A and the second surface layer 10B. The first surface layer 10A includes a first surface 101, and the second surface layer 10B includes a second surface 102. In the first surface layer 10A (or the second surface layer 10B), the proportion of the second pores 12 can be greater than the proportion of the first pores 11; in the intermediate layer 10C, the proportion of the second pores 12 can be less than the proportion of the first pores 11. Furthermore, the proportion of the second pores 12 in the active material layer 10 can vary regularly, that is, along the thickness direction of the active material layer 10, the proportion of the second pores 12 tends to first decrease and then increase. It should be explained that the proportion of the second pores 12 is the ratio of the second pores 12 to the total pores in the unit volume of the active material layer 10, that is, the ratio of the porosity A2 of the second pores 12 to the total porosity σ.

[0075] By setting the proportion of the second pores 12 in the active material layer 10 to first decrease and then increase, the second pores 12 at the surface layer account for a larger proportion, making it easier for the electrolyte to invade the active material layer 10 from the surface layer, thereby improving the wettability of the electrolyte; moreover, the first pores 11 in the intermediate layer 10C account for a larger proportion, which can improve the contact between the electrolyte and each active particle 13, further improving the wettability of the electrolyte to the active material layer 10 as a whole.

[0076] In one embodiment, the median particle size D50 of the active particles 13 satisfies the following relationship: 100 nm ≤ D50 ≤ 30 μm. Specifically, satisfying the above relationship allows for better control of the particle size in the active material layer 10, preventing particles from being too small or too small, thereby ensuring that the active material layer has both the first pores 11 and the second pores 12.

[0077] Optionally, the median particle size D50 of the active particles 13 may be, but is not limited to, 100 nm, 200 nm, 300 nm, 500 nm, 800 nm, 1 μm, 2 μm, 3 μm, 5 μm, 8 μm, 10 μm, 20 μm, or 30 μm. The median particle size D50 of the active particles 13 can be obtained by measuring the particle size cross-section of multiple active particles 13 on the longitudinal section of the active material layer 10 using a scanning electron microscope, and then measuring the particle size distribution using ImageJ software. Specifically, a SEM photograph of the longitudinal section of the active material layer 10 at a magnification of 5000 times is obtained using a scanning electron microscope. An area with a length and width of 0.5 cm*0.5 cm is selected from the SEM photograph, and the particle sizes of multiple active particles 13 in the area are measured. The particle size distribution is measured using ImageJ software to obtain D50. On the longitudinal section of the active material layer 10, the active particles 13 have different profiles. The particle size of a single active particle 13 is obtained by measuring the two closest points of each particle profile.

[0078] By controlling the lower and upper limits of the particle size of the active particles 13 and combining them with the relationship in the above embodiment, the porosity and distribution ratio of the first pores 11 in the active material layer 10 can be reasonably set, thereby ensuring the requirements of electrolyte immersion and ion migration in the active material layer 10 while obtaining a high-capacity electrode 100.

[0079] In one embodiment, the present application further provides a method for manufacturing a pole piece, as shown in FIG4 , comprising the following steps:

[0080] Step S10: preparing a mixed powder containing active materials.

[0081] In step S20 , an active material layer is prepared using the mixed powder, and the active material layer is disposed on a current collector.

[0082] The active material layer includes a plurality of active particles, and the active material layer also has a first pore and a second pore; the pore size R1 of the first pore and the pore size R2 of the second pore satisfy: 0.05*D50≤R1<0.65*D50, 0.65*D50≤R1≤10*D50, wherein D50 is the median particle size of the active particles.

[0083] Specifically, in step S10, preparing the mixed powder containing the active material includes: pre-mixing the active material, the binder and the conductive agent in proportion to obtain a pre-mixed powder; putting the pre-mixed powder into a jet mill for grinding and mixing to obtain a jet mill mixed powder.

[0084] Alternatively, the active material (particles), binder, and conductive agent are weighed in appropriate proportions and pre-mixed in a V-type mixer. The binder mass percentage is 1.5% to 5%, and the conductive agent mass percentage is 0.3% to 2%. The pre-mixed powder is then placed in a jet mill for grinding and mixing, with a crushing pressure range of 0.1 MPa to 0.8 MPa.

[0085] Optionally, in step S20, an active material layer is prepared using a mixed powder, and the active material layer is arranged on the current collector, which may include: rolling the air flow milled mixed powder to form a first self-supporting film; rolling the first self-supporting film to form a second self-supporting film; and bonding the second self-supporting film to the current collector to obtain the pole piece.

[0086] Optionally, the obtained air flow mill mixed powder is rolled into a self-supporting membrane (i.e., the first self-supporting membrane) by a hot roller press. The rolling line pressure range is 0.1t / cm~1t / cm, the differential speed ratio satisfies 1:1~1:3, and the temperature range is 100℃~250℃. Then, the self-supporting membrane is passed through a calendering roller press for 2 stages of calendering to obtain a thinned membrane (i.e., the second self-supporting membrane), the calendering line pressure range is 0.1t / cm~1t / cm, the differential speed ratio satisfies 1:1~1:3, and the temperature range is 60℃~180℃. Finally, the two membranes are hot-pressed with a foil with a primer to form a pole piece with the required porosity. By controlling the calendering line pressure range to 0.1t / cm~1t / cm and the differential speed ratio to 1:1~1:3, the self-supporting membrane presents a regular pore distribution. The differential speed ratio refers to the speed ratio between the upper roller (lower roller) and the lower roller (upper roller) of the roller press.

[0087] Optionally, the proportion of the second pores in the active material layer (i.e., the self-supporting membrane) may vary regularly, i.e., the proportion of the second pores decreases first and then increases along the thickness of the active material layer. It should be noted that the proportion of the second pores is the ratio of the second pores to the total pores per unit volume of the active material layer.

[0088] Optionally, the active material (particles), binder, and conductive agent in this embodiment can all refer to those provided in the above embodiments, and are not described in detail here.

[0089] In one embodiment, as shown in FIG6 , the present application further provides a battery 1000 comprising a separator 200 and the electrode sheet 100 described above, wherein the electrode sheet 100 comprises a positive electrode sheet and a negative electrode sheet, and the positive electrode sheet and the negative electrode sheet are respectively arranged on opposite sides of the separator 200. The present application does not limit the specific type of battery, and both the positive electrode sheet and the negative electrode sheet of the battery can be prepared using the above method. In one embodiment, the battery 1000 further comprises an electrolyte 300.

[0090] In one embodiment, as shown in FIG7 , the present application further provides a power system 2000, which includes a power device 3000 and a battery 1000, wherein the battery 1000 is used to power the power device 3000. The power system 2000 may be a new energy vehicle or an energy storage power station.

[0091] The technical solution of the present invention is described in detail below through specific embodiments.

[0092] Example 1

[0093] This embodiment provides a positive electrode plate, wherein the active particles are lithium iron phosphate, and the active material layer has a first pore and a second pore, wherein the particle size D50 of the active particles is 1 μm; wherein the pore size of the first pore is approximately 90 nm, and the porosity A1 of the first pore is 26.7%; wherein the pore size of the second pore is approximately 1 μm, and the porosity A2 of the second pore is 4%, and the correction coefficient A is 30%. The positive electrode plate is manufactured as follows:

[0094] 1) Lithium iron phosphate, a conductive agent, and a binder were added to a V-type mixer in a ratio of 100:1:3 and mixed, and then put into a jet mill and ground at a pressure of 0.6 MPa to obtain a homogenized dry powder.

[0095] 2) The homogenized dry powder was uniformly conveyed to a horizontal hot roller press with a pressure of 1 t / cm, a roller gap of 100 μm, a differential speed of 1:1, and a temperature of 150°C.

[0096] 3) The electrode film formed initially is rolled to 220g / m by a rolling roller with a pressure of 1t / cm, a differential speed of 1:1, and a temperature of 150°C. 2 Surface density (calendering roller gap is adjusted according to surface density).

[0097] 4) The rolled electrode and the aluminum foil with the primer layer are thermally composited at 150°C to obtain the target electrode, and then the electrode is compacted to 2.5g / cm by roller pressing. 3 .

[0098] Example 2

[0099] This embodiment provides a positive electrode plate, wherein the active particles are lithium iron phosphate, and the active material layer has a first pore and a second pore. The particle size D50 of the active particles is 1 μm. The first pore has a pore size of approximately 200 nm and a porosity A1 of 28%. The second pore has a pore size of approximately 700 nm and a porosity A2 of 2%. The correction factor A is 30%. The positive electrode plate is manufactured as follows:

[0100] 1) Lithium iron phosphate, a conductive agent, and a binder were added to a V-type mixer in a ratio of 100:1:3, mixed, and then added to a jet mill and ground at a pressure of 0.6 MPa to obtain a homogenized dry powder.

[0101] 2) The homogenized dry powder was uniformly conveyed to a horizontal hot roller press with a pressure of 1 t / cm, a roller gap of 100 μm, a differential speed of 1:1.5, and a temperature of 150°C.

[0102] 3) The electrode film formed initially is rolled to 220g / m by a rolling roller with a pressure of 1t / cm, a differential speed of 1:1.5, and a temperature of 150°C. 2 Surface density (calendering roller gap is adjusted according to surface density).

[0103] 4) The rolled electrode and the aluminum foil with the primer layer are thermally composited at 150°C to obtain the target electrode, and then the electrode is compacted to 2.5g / cm by roller pressing. 3 .

[0104] Example 3

[0105] This embodiment provides a positive electrode plate, wherein the active particles are lithium iron phosphate, and the active material layer has a first pore and a second pore, wherein the particle size D50 of the active particles is 1 μm; wherein the pore size of the first pore is approximately 90 nm, and the porosity A1 of the first pore is 23.5%; wherein the pore size of the second pore is approximately 1 μm, and the porosity A2 of the second pore is 2.5%, and the correction coefficient A is 25%. The positive electrode plate is manufactured as follows:

[0106] 1) Lithium iron phosphate, a conductive agent, and a binder were added to a V-type mixer in a ratio of 100:1:3 and mixed, and then put into a jet mill and ground at a pressure of 0.6 MPa to obtain a homogenized dry powder.

[0107] 2) The homogenized dry powder was uniformly conveyed to a horizontal hot roller press with a pressure of 1 t / cm, a roller gap of 100 μm, a differential speed of 1:1, and a temperature of 150°C.

[0108] 3) The electrode film formed initially is rolled to 220g / m by a rolling roller with a pressure of 1t / cm, a differential speed of 1:1, and a temperature of 150°C. 2 Surface density (calendering roller gap is adjusted according to surface density).

[0109] 4) The rolled electrode and the aluminum foil with the primer layer are thermally composited at 150°C to obtain the target electrode, and then the electrode is compacted to 2.5g / cm by roller pressing. 3 .

[0110] Example 4

[0111] This embodiment provides a positive electrode plate, wherein the active particles are lithium iron phosphate, and the active material layer has a first pore and a second pore. The particle size D50 of the active particles is 1 μm. The first pore has a pore size of approximately 600 nm and a porosity A1 of 34%. The second pore has a pore size of approximately 9000 nm and a porosity A2 of 0.4%. The correction factor A is 35%. The positive electrode plate is manufactured as follows:

[0112] 1) Lithium iron phosphate, a conductive agent, and a binder were added to a V-type mixer in a ratio of 100:1:3, mixed, and then added to a jet mill and ground at a pressure of 0.6 MPa to obtain a homogenized dry powder.

[0113] 2) The homogenized dry powder was uniformly conveyed to a horizontal hot roller press with a pressure of 1 t / cm, a roller gap of 100 μm, a differential speed of 1:2, and a temperature of 150°C.

[0114] 3) The electrode film formed initially is rolled to 220g / m by a rolling roller with a pressure of 1t / cm, a differential speed of 1:3, and a temperature of 150°C. 2 Surface density (calendering roller gap is adjusted according to surface density).

[0115] 4) The rolled electrode and the aluminum foil with the primer layer are thermally composited at 150°C to obtain the target electrode, and then the electrode is compacted to 2.5g / cm by roller pressing. 3 .

[0116] Example 5

[0117] This embodiment provides a positive electrode plate, wherein the active particles are lithium iron phosphate, and the active material layer has a first pore and a second pore. The particle size D50 of the active particles is 1 μm. The first pore has a pore size of approximately 500 nm and a porosity A1 of 35%. The second pore has a pore size of approximately 8800 nm and a porosity A2 of 0.4%. The correction factor A is 35%. The positive electrode plate is manufactured as follows:

[0118] 1) Lithium iron phosphate, a conductive agent, and a binder were added to a V-type mixer in a ratio of 100:1:3, mixed, and then added to a jet mill and ground at a pressure of 0.6 MPa to obtain a homogenized dry powder.

[0119] 2) The homogenized dry powder was uniformly conveyed to a horizontal hot roller press with a pressure of 1 t / cm, a roller gap of 100 μm, a differential speed of 1:2.5, and a temperature of 150°C.

[0120] 3) The electrode film formed initially is rolled to 220g / m by a rolling roller with a pressure of 1t / cm, a differential speed of 1:3, and a temperature of 150°C. 2 Surface density (calendering roller gap is adjusted according to surface density).

[0121] 4) The rolled electrode and the aluminum foil with the primer layer are thermally composited at 150°C to obtain the target electrode, and then the electrode is compacted to 2.5g / cm by roller pressing. 3 .

[0122] Example 6

[0123] This embodiment provides a positive electrode plate, wherein the active particles are lithium iron phosphate, and the active material layer has a first pore and a second pore. The particle size D50 of the active particles is 1 μm. The first pore has a pore size of approximately 550 nm and a porosity A1 of 38%. The second pore has a pore size of approximately 8000 nm and a porosity A2 of 0.2%. The correction factor A is 40%. The positive electrode plate is manufactured as follows:

[0124] 1) Lithium iron phosphate, a conductive agent, and a binder were added to a V-type mixer in a ratio of 100:1:3, mixed, and then added to a jet mill and ground at a pressure of 0.6 MPa to obtain a homogenized dry powder.

[0125] 2) The homogenized dry powder was uniformly conveyed to a horizontal hot roller press with a pressure of 1 t / cm, a roller gap of 100 μm, a differential speed of 1:3, and a temperature of 150°C.

[0126] 3) The electrode film formed initially is rolled to 220g / m by a rolling roller with a pressure of 1t / cm, a differential speed of 1:3, and a temperature of 150°C. 2 Surface density (calendering roller gap is adjusted according to surface density).

[0127] 4) The rolled electrode and the aluminum foil with the primer layer are thermally composited at 150°C to obtain the target electrode, and then the electrode is compacted to 2.5g / cm by roller pressing. 3 .

[0128] Comparative Example 1

[0129] Conventional wet coating was used. The ratio of lithium iron phosphate, conductive agent and binder was 100:1:3. The mixture was added into a blender to prepare wet slurry. The slurry was then coated onto aluminum foil. The surface density was controlled to be 220g / m 2 , and then the compaction was controlled by roller pressing to 2.5g / cm 3 ; The obtained positive electrode plate has active particles of lithium iron phosphate, and the active material layer has first pores and second pores, wherein the particle size D50 of the active particles is 1 μm; wherein, the pore size of the first pore is about 800 nm, and the porosity A1 of the first pore is 28%; the pore size of the second pore is about 11 μm, and the porosity A2 of the second pore is 0.015%, and the correction coefficient A is 28%.

[0130] Comparative Example 2

[0131] This comparative example provides a positive electrode plate. The obtained positive electrode plate has active particles of lithium iron phosphate, and has a first pore and a second pore in the active material layer, wherein the particle size D50 of the active particle is 1 μm; wherein the pore size of the first pore is approximately 40 nm, and the porosity A1 of the first pore is 25%; the pore size of the second pore is approximately 1 μm, and the porosity A2 of the second pore is 0.12%, and the correction coefficient A is 25%.

[0132] The production method of the positive electrode is as follows:

[0133] 1) Lithium iron phosphate, a conductive agent, and a binder were added to a V-type mixer in a ratio of 100:1:3, mixed, and then added to a jet mill and ground at a pressure of 0.6 MPa to obtain a homogenized dry powder.

[0134] 2) The homogenized dry powder was uniformly conveyed to a horizontal hot roller press with a pressure of 1 t / cm, a roller gap of 100 μm, a constant speed, and a temperature of 150°C.

[0135] 3) The electrode film formed initially is rolled to 220g / m by a rolling roller with a pressure of 1t / cm, a uniform speed and a temperature of 150℃. 2 Surface density (calendering roller gap is adjusted according to surface density).

[0136] 4) The rolled electrode and the aluminum foil with the primer layer are thermally composited at 150°C to obtain the target electrode, and then the electrode is compacted to 2.5g / cm by roller pressing. 3 .

[0137] The pole pieces provided in Examples 1 to 6 and Comparative Examples 1 and 2 above were subjected to the following calculations and tests:

[0138] The ratio of the porosity A2 of the second pore to the porosity A1 of the first pore is calculated as η = A2 / A1, and the compacted density is 2.5 g / cm 3 The overall porosity σ of the corresponding lithium iron phosphate is 30%.

[0139] Porosity test (using mercury intrusion method): test range 0.1psia~61000psia.

[0140] Aperture test method: Use scanning electron microscopy to test, and then use ImageJ software to measure the distance distribution between the two nearest points of the contour; it can also be obtained through the pore size distribution curve.

[0141] Active particle D50: can be obtained by scanning electron microscopy testing and then measuring the particle size distribution using ImageJ software.

[0142] Electrode DCIR (DC internal resistance) test: Ensure the counter electrode is consistent. You can use lithium sheets as the counter electrode. After formation, adjust the discharge to 50% SOC, let it stand for 1 hour, and then discharge at 1.5C for 30 seconds. The difference between the end voltage and the starting voltage is ΔV. The test current of 1.5C is I, then DCIR = ΔV / I.

[0143] Rate performance test: The battery is prepared as above. After discharging into different capacities, it is charged to 100% SOC at 0.33C, and then discharged to the cut-off voltage at 1C and 3C to obtain different rate capacities. The rate capacity percentage Q is obtained by dividing the 3C rate capacity by the 1C rate capacity.

[0144] Low temperature performance test: The battery was prepared as above. After discharging into different capacities, it was charged to 100% SOC at 0.33C. Then it was discharged to the cut-off voltage at 0.33C at 25℃ and 0℃ respectively to obtain different low temperature capacities. The low temperature capacity percentage q was obtained by dividing the capacity at 0℃ by the capacity at 25℃.

[0145] After testing and calculation, the performance comparison results in Table 1 were obtained.

[0146] Table 1

[0147] FIG5 is a pore size distribution diagram of Example 1 and Comparative Example 1, wherein the novel pore size distribution is Example 1 and the conventional pore size distribution is Comparative Example 1. As can be seen from FIG5 , the distribution rate of large pores in Example 1 is higher than that in Comparative Example 1, which also illustrates that the electrode prepared according to the manufacturing method provided in this application has a pore distribution with different pore sizes.

[0148] The test results in Table 1 show that the ratio of second pore to first pore in Examples 1-6 is greater than that in Comparative Examples 1 and 2, indicating that the proportion of large pores in the Examples is higher. Consequently, thanks to the combined effects of large and small pores, the electrode's DC internal resistance (DCIR), rate capacity percentage (Q), and low-temperature capacity percentage (q) are all higher than those in Comparative Examples 1 and 2. This demonstrates that the synergistic effect of the first and second pores can improve battery performance.

[0149] In the description of the embodiments of the present application, it should be noted that the orientation or positional relationship of terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", and "outside" are based on the orientation or positional relationship described in the accompanying drawings. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present application.

[0150] The above disclosure is only a preferred embodiment of the present application, and certainly cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made in accordance with the claims of the present application are still within the scope covered by the present application.

Claims

1. A pole piece (100), characterized in that: include: A current collector (20) and an active material layer (10) arranged in a stacked manner; The active material layer (10) includes a plurality of active particles (13), and the active material layer (10) also has a first pore (11) and a second pore (12); The pore size R1 of the first pore (11) and the pore size R2 of the second pore (12) satisfy: 0.05*D50≤R1<0.65*D50, 0.65*D50≤R2≤10*D50, wherein D50 is the median particle size of the plurality of active particles (13), and the units of R1 and R2 are nm.

2. The pole piece (100) according to claim 1, characterized in that: The porosity A1 of the first pores (11) satisfies: 15%≤A1≤34.5%; the porosity A2 of the second pores (12) satisfies: 0.3%≤A2≤10%.

3. The pole piece (100) according to claim 1 or 2, characterized in that: The total porosity of the active material layer (10) is σ, the total porosity σ includes the porosity A1 of the first pores (11) and the porosity A2 of the second pores (12), and the total porosity σ satisfies: 25%≤σ≤35%, and A1+A2≤σ.

4. The pole piece (100) according to claim 3, characterized in that: The ratio η of the porosity A2 of the second pore (12) to the porosity A1 of the first pore (11) is A2 / A1, which satisfies: 1%*(σ / A)≤η≤15%*(σ / A), wherein A is the correction coefficient of the total porosity σ of the active material layer (10), and A satisfies: 25%≤A≤35%.

5. The pole piece (100) according to claim 3 or 4, characterized in that: A ratio η of the porosity A2 of the second pores (12) to the porosity A1 of the first pores (11) is A2 / A1, satisfying: 1%*(σ / 30%)≤η≤15%*(σ / 30%).

6. The pole piece (100) according to claim 2, characterized in that: A ratio η of the porosity A2 of the second pores (12) to the porosity A1 of the first pores (11) is A2 / A1, which satisfies: 1%≤η≤15%.

7. The pole piece (100) according to any one of claims 1 to 6, characterized in that: The active material layer (10) comprises a first surface (101) and a second surface (102) which are opposite to each other, the first surface (101) being connected to the current collector (20); and in a direction from the first surface (101) to the second surface (102), the proportion of the second pores (12) tends to first decrease and then increase.

8. The pole piece (100) according to any one of claims 1 to 7, characterized in that: The median particle size D50 of the active particles (13) satisfies: 100 nm ≤ D50 ≤ 30 μm.

9. A method for manufacturing a pole piece, characterized in that: include: Preparing a mixed powder containing active materials (S10); Using the mixed powder to prepare an active material layer, and placing the active material layer on a current collector (S20); The active material layer includes a plurality of active particles, and the active material layer also has a first pore and a second pore; The pore size R1 of the first pore and the pore size R2 of the second pore satisfy: 0.05*D50≤R1<0.65*D50, 0.65*D50≤R1≤10*D50, wherein D50 is the median particle size of the active particles.

10. The manufacturing method according to claim 9, characterized in that: The method for preparing a mixed powder containing active materials comprises: Premixing the active material, the binder and the conductive agent in proportion to obtain a premixed powder; The premixed powder is put into a jet mill for grinding and mixing to obtain jet mill mixed powder.

11. The manufacturing method according to claim 10, characterized in that: The mass percentage of the binder is 1.5% to 5%, the mass percentage of the conductive agent is 0.3% to 2%, and the premixed powder is put into a jet mill for grinding and mixing at a crushing pressure range of 0.1 MPa to 0.8 MPa.

12. The production method according to claim 10 or 11, characterized in that: The step of preparing the active material layer by using the mixed powder and disposing the active material layer on the current collector comprises: The jet milled mixed powder is rolled to form a first self-supporting film; Calendering the first self-supporting film to form a second self-supporting film; The second self-supporting film is bonded to the current collector to obtain the pole piece.

13. The manufacturing method according to claim 12, characterized in that: The rolling line pressure range for forming the first self-supporting film is 0.1t / cm~1t / cm, the differential ratio satisfies 1:1~1:3, and the temperature range is 100℃~250℃; the calendering line pressure range for forming the second self-supporting film is 0.1t / cm~1t / cm, the differential ratio satisfies 1:1~1:3, and the temperature range is 60℃~180℃; the calendering line pressure range for bonding the second self-supporting film to the collector to obtain the pole piece is 0.1t / cm~1t / cm, and the differential ratio satisfies 1:1~1:

3.

14. A battery (1000), characterized in that: The invention comprises a diaphragm (200) and a pole piece (100) as claimed in any one of claims 1 to 8, wherein the pole piece (100) comprises a positive pole piece and / or a negative pole piece; or the battery (1000) comprises a diaphragm (200) and a pole piece (100) manufactured by the pole piece manufacturing method as claimed in any one of claims 9 to 13, wherein the pole piece (100) comprises a positive pole piece and / or a negative pole piece.

15. An electricity system (2000), characterized in that: The power consumption system (2000) comprises a power consumption device (3000) and a battery (1000) as claimed in claim 14, wherein the battery (1000) is used to supply power to the power consumption device (3000).

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