Battery electrode sheet, battery, and electric device

Abstract

An electric device. The electric device comprises a battery, and the battery comprises a battery electrode sheet. The battery electrode sheet comprises a current collector, a first active material layer, and a second active material layer. The first active material layer is arranged on the current collector. The second active material layer is arranged on the side of the first active material layer away from the current collector. The first active material layer comprises a first conductive agent, and the first conductive agent comprises carbon black and / or graphene. The second active material layer comprises a second conductive agent, and the second conductive agent comprises carbon black and / or graphene. The first conductive agent has a first shape and size, the second conductive agent has a second shape and size, and the first shape is different from the second shape, or the first size is different from the second size.

Description

Battery pole piece, battery and electric device

[0001] Cross-reference to Related Applications

[0002] The present application claims priority to the Chinese patent application No. 202410652580.6, filed on May 24, 2024, entitled "Battery pole piece, battery and electric device", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of batteries, in particular to a battery pole piece, a battery and an electric device. BACKGROUND

[0004] The conventional pole piece is only designed to have one active material coating layer, which cannot meet the different functional requirements of the pole piece in different environments, and the single coating layer will cause low ion diffusion rate of the coating layer far from the current collector and low electron conduction rate of the coating layer close to the current collector, which cannot achieve the effect that the ion diffusion and electron conduction of the entire pole piece are adapted to each other, thereby affecting the battery performance.

[0005] SUMMARY

[0006] The purpose of the present application is to provide a battery pole piece, a battery and an electric device, which solve the problems of low ion diffusion rate of the coating layer far from the current collector and low electron conduction rate of the coating layer close to the current collector in the single coating layer.

[0007] To achieve the purpose of the present application, the present application provides the following technical solutions:

[0008] In a first aspect, the present application provides a battery pole piece, comprising a current collector; a first active material layer, the first active material layer being arranged on the current collector, the first active material layer comprising a first conductive agent, the first conductive agent comprising carbon black and / or graphene; and a second active material layer, the second active material layer being arranged on a side of the first active material layer away from the current collector, the second active material layer comprising a second conductive agent, the second conductive agent comprising carbon black and / or graphene; the first conductive agent has a first shape size, the second conductive agent has a second shape size, and the first shape size and the second shape size are different.

[0009] In an embodiment, when the first conductive agent and the second conductive agent both comprise carbon black, the carbon black particle size Dv50 in the first active material layer is smaller than the carbon black particle size Dv50 in the second active material layer; when the first conductive agent and the second conductive agent both comprise graphene, the flake size of the graphene in the first active material layer is larger than the flake size of the graphene in the second active material layer.

[0010] In an embodiment, when the first conductive agent comprises carbon black, the carbon black in the first active material layer has a particle size Dv50 of 6.3 nm to 14.8 nm; when the second conductive agent comprises carbon black, the carbon black in the second active material layer has a particle size Dv50 of 22 nm to 111 nm; when the first conductive agent comprises graphene, the graphene in the first active material layer has a flake size of 2 μm to 10 μm; and when the second conductive agent comprises graphene, the graphene in the second active material layer has a flake size of 0.1 μm to 1.5 μm.

[0011] In an embodiment, the first conductive agent and the second conductive agent further comprise carbon nanotubes.

[0012] In an embodiment, the carbon nanotubes in the first active material layer have a length-diameter ratio greater than that of the carbon nanotubes in the second active material layer.

[0013] In an embodiment, the carbon nanotubes in the first active material layer have a length-diameter ratio of 500 to 800; and / or the carbon nanotubes in the second active material layer have a length-diameter ratio of 200 to 590.

[0014] In an embodiment, the first active material layer comprises first active material particles, and the second active material layer comprises second active material particles; the first active material particles have a particle size Dv50 less than that of the second active material particles.

[0015] In an embodiment, the first active material particles have a particle size Dv50 of 0.01 μm to 0.8 μm; and / or the second active material particles have a particle size Dv50 of 0.7 μm to 1.5 μm.

[0016] In a second aspect, the present application provides a battery comprising an electrolyte and the battery pole piece of the first aspect, wherein the battery pole piece is soaked in the electrolyte.

[0017] In a third aspect, the present application provides a power-consuming device comprising the battery of the second aspect and a power-consuming component, wherein the battery supplies power to the power-consuming component.

[0018] The application provides a battery pole piece, comprising a current collector, a first active material layer and a second active material layer, the first active material layer is arranged on the current collector, the second active material layer is arranged on the side of the first active material layer away from the current collector, the first active material layer comprises a first conductive agent, the first conductive agent comprises carbon black and / or graphene, the second active material layer comprises a second conductive agent, the second conductive agent comprises carbon black and / or graphene, the first conductive agent has a first shape size, the second conductive agent has a second shape size, and the first shape size and the second shape size are different. Through the above arrangement, the conductive agents with different shape sizes construct different ion transmission channels and electron transmission networks in the active material layers, so that different ion transmission rates and electron conduction rates are realized in the two active material layers, the transmission efficiency of electrons and ions in the active material layers is optimized through the double-layer design, and the battery performance is improved. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0020] Fig. 1 is a schematic diagram of a double-layer active material layer according to an embodiment of the present application;

[0021] Fig. 2 is a schematic diagram of a manufacturing method of a pole piece according to an embodiment of the present application;

[0022] Fig. 3 is a schematic block diagram of a battery according to an embodiment of the present application;

[0023] Fig. 4 is a schematic block diagram of an electrical equipment according to an embodiment of the present application.

[0024] Reference signs: 10, battery pole piece; 20, battery; 21, electrical device; 30, electrical equipment; 1, first active material layer; 2, second active material layer; 3, current collector. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort fall within the scope of protection of the present application.

[0026] It should be understood that when an element as a layer, region or plate is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. In addition, it should be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements can be present. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety.

[0028] Some embodiments of the application will now be described in detail in connection with the accompanying drawings. From the following description, the skilled person will understand that the examples and features described below can be combined with each other, without conflicting.

[0029] Glossary and specific test methods used in this application:

[0030] Dv50: refers to the value of Dv50 in the volume distribution of the particle material, 50% of the particle volume is less than or equal to the value of Dv50, and the other 50% of the particle volume is greater than or equal to the value of Dv50.

[0031] Sheet diameter: refers to the width or transverse dimension of the sheet material.

[0032] Aspect ratio: refers to the ratio of the length of the tubular material to its diameter.

[0033] Particle size Dv50 of carbon black: by scanning electron microscope (SEM) test, SEM is used to take the image of carbon black, and the particle size Dv50 of carbon black is measured by image analysis.

[0034] Graphene sheet diameter ratio: by scanning electron microscope (SEM) test, SEM is used to take the image of graphene, and the graphene sheet diameter ratio is measured by image analysis.

[0035] Aspect ratio of carbon nanotube: by scanning electron microscope (SEM) test, SEM is used to take the image of carbon nanotube, and the aspect ratio of carbon nanotube is measured by image analysis.

[0036] Particle size Dv50 of active material particles: by scanning electron microscope (SEM) test, SEM is used to take the image of active material particles, and the particle size Dv50 of active material particles is measured by image analysis.

[0037] In one embodiment, the present application provides a battery pole piece 10, the battery pole piece 10 comprising a current collector 3, a first active material layer 1 and a second active material layer 2, the first active material layer 1 being disposed on the current collector 3, the first active material layer 1 comprising a first conductive agent, the first conductive agent comprising carbon black and / or graphene; the second active material layer 2 being disposed on a side of the first active material layer 1 away from the current collector 3, the second active material layer 2 comprising a second conductive agent, the second conductive agent comprising carbon black and / or graphene; the first conductive agent having a first shape size, the second conductive agent having a second shape size, the first shape size being different from the second shape size.

[0038] Referring to FIG. 1, the first active material layer 1 is closer to the current collector 3, and the second active material layer 2 is away from the current collector 3; the second active material layer 2 mainly plays a role of making lithium ions in the electrolyte diffuse in the solid active material layer, while the first active material layer 1 needs to enable electrons to be more effectively transferred to the current collector 3. Different ion transmission channels and electron transmission networks in the active material layer can realize different ion transmission rates and electron conduction rates in the active material layer. The first shape size of the first conductive agent and the second shape size of the second conductive agent are different, which can be but not limited to the particle size, aspect ratio and flake diameter of the conductive agent. By different shape sizes of the conductive agent, different ion transmission channels and electron transmission networks are constructed in the first active material layer 1 and the second active material layer 2, so as to realize different ion transmission rates and electron conduction rates in the first active material layer 1 and the second active material layer 2. By the double-layer design, the transmission efficiency of electrons and ions in the active material layer can be optimized, and the battery performance can be improved.

[0039] Specifically, the first shape size of the first conductive agent and the second shape size of the second conductive agent are different. When the first conductive agent and the second conductive agent are both carbon black, the shapes of the carbon black particles are the same, and the particle size Dv50 of the carbon black in the first active material layer 1 is smaller or larger than the particle size Dv50 of the carbon black in the second active material layer 2. When the first conductive agent and the second conductive agent are both graphene, the shapes of the graphene flakes are the same, and the flake diameter of the graphene in the first active material layer 1 is larger or smaller than the flake diameter of the graphene in the second active material layer 2. When the first conductive agent is carbon black and the second conductive agent is graphene, there is no comparability between the sizes of different shapes, and only the first shape size and the shape of the second conductive agent are different. Therefore, it can be understood that the shape sizes of the conductive agents shown in the present application can be different shapes of the conductive agents, or different sizes of the conductive agents, and it cannot be considered that the shape and size of the first conductive agent and the shape and size of the second conductive agent are both different.

[0040] Carbon black and / or graphene are added to the first active material layer 1 and the second active material layer 2. Due to the high specific surface area of carbon black, it can provide a large number of electron transport channels, and the two-dimensional planar structure of graphene is stable, which can form a stable conductive network. These materials can effectively improve the conductivity of the electrode, increase the contact area of active material and electrolyte, thereby improving the capacity and energy density of the battery.

[0041] Carbon black and graphene both have high conductivity, but their shapes and sizes are different. Carbon black usually exists in the form of small particles, while graphene is a two-dimensional material composed of single or a few layers of carbon atoms. In the active material layer, carbon black and graphene together form a three-dimensional conductive network. Carbon black fills the gaps between graphene layers, increasing the density and continuity of the entire network, while graphene provides high-conductivity channels for electrons to quickly transport throughout the network. The synergistic effect of carbon black and graphene improves the efficiency of electron transport in the active material layer. Small particles of carbon black can form more contact points with active material particles, reducing the contact resistance of electron transport. The high conductivity and large specific surface area of graphene provide more transport channels for electrons, allowing them to move quickly between the active material and the current collector. The layered structure of graphene provides a diffusion path for ions, helping them transport within the electrode. The presence of carbon black increases the porosity of the electrode, providing more space for ion migration.

[0042] Carbon nanotubes can also be added to the first active material layer 1 and the second active material layer 2, which can act as a bridge connecting carbon black and graphene to form a more complete three-dimensional conductive network. Carbon nanotubes have a high aspect ratio, which can span a long distance, thereby improving the connectivity of the entire conductive network and facilitating the rapid transport of electrons throughout the electrode. The high conductivity and unique tubular structure of carbon nanotubes provide additional transport paths for electrons, which can shorten the transport distance and reduce resistance. At the same time, the presence of carbon nanotubes can further improve the conductivity of the electrode, especially under high-rate charging and discharging conditions. The large specific surface area and tubular structure of carbon nanotubes provide more channels for ion diffusion, which helps the transport of ions within the electrode. In addition, carbon nanotubes can reduce the blockage of channels within the electrode, maintaining the flowability of the electrolyte, thereby improving the transport efficiency of ions. The synergistic effect of the three can optimize the charging and discharging performance of the electrode, improve the capacity retention rate and cycle stability of the battery. The presence of carbon nanotubes can provide more active sites, increase the contact area of the electrode and electrolyte, and thereby improve the capacity and energy density of the battery.

[0043] When the materials in the first conductive agent and the second conductive agent are the same. Both the first conductive agent and the second conductive agent include carbon black, and carbon black with different particle sizes can provide different ion transmission channels and electron transmission networks, so as to realize different ion transmission rates and electron conduction rates in the first active material layer 1 and the second active material layer 2. Or both the first conductive agent and the second conductive agent include graphene, and graphene with different sheet sizes can provide different ion transmission channels and electron transmission networks, so as to realize different ion transmission rates and electron conduction rates in the first active material layer 1 and the second active material layer 2.

[0044] When the materials in the first conductive agent and the second conductive agent are different. The first conductive agent includes carbon black, and the second conductive agent includes graphene. The carbon black in the first conductive agent and the graphene in the second conductive agent provide different ion transmission channels and electron transmission networks due to different shapes, so as to realize different ion transmission rates and electron conduction rates in the first active material layer 1 and the second active material layer 2. Or the first conductive agent includes graphene, and the second conductive agent includes carbon black. The graphene in the first conductive agent and the carbon black in the second conductive agent provide different ion transmission channels and electron transmission networks due to different shapes, so as to realize different ion transmission rates and electron conduction rates in the first active material layer and the second active material layer.

[0045] The application provides a battery pole piece 10, which includes a current collector 3, a first active material layer 1 and a second active material layer 2, the first active material layer 1 is arranged on the current collector 3, and the second active material layer 2 is arranged on a side of the first active material layer 1 away from the current collector 3, the first active material layer 1 includes a first conductive agent, the first conductive agent includes carbon black and / or graphene, the second active material layer 2 includes a second conductive agent, the second conductive agent includes carbon black and / or graphene, the first conductive agent has a first shape size, the second conductive agent has a second shape size, and the first shape size and the second shape size are different. Through the above arrangement, the conductive agents with different shape sizes construct different ion transmission channels and electron transmission networks in the active material layers, so as to realize different ion transmission rates and electron conduction rates in the two active material layers, the transmission efficiency of electrons and ions in the active material layers can be optimized through the double-layer design, and the battery performance is improved.

[0046] In an implementation, when the first conductive agent and the second conductive agent both include carbon black, the particle size Dv50 of the carbon black in the first active material layer 1 is smaller than the particle size Dv50 of the carbon black in the second active material layer 2.

[0047] The first active material layer 1 needs to have a high electron conduction rate. The carbon black particle size Dv50 is small and has a high specific surface area, which can provide more electron transmission channels, thereby enhancing the conduction efficiency of electrons. The larger carbon black particle size Dv50 in the second active material layer 2 helps to form more ion transmission channels, thereby improving the diffusion efficiency of ions.

[0048] In an embodiment, the carbon black particle size Dv50 of the first active material layer 1 is 6.3 nm-14.8 nm; and / or, the carbon black particle size Dv50 of the second active material layer 2 is 22 nm-111 nm. Optionally, the carbon black particle size Dv50 of the first active material layer 1 can be, but is not limited to, 6.3 nm, 7.8 nm, 9.3 nm, 10.8 nm, 12.3 nm, 13.8 nm, 14.8 nm.

[0049] The carbon black particle size Dv50 of the first active material layer 1 in this range can provide a high specific surface area, and the carbon black of a unit mass has more surfaces available for reaction, which will not cause the formation of pores in the electrode sheet, increase the density of the electrode sheet, thereby increasing the contact area of the active material and the electrolyte, improving the transmission efficiency of ions and the rate of electrochemical reaction, and forming a more effective conductive network, which can improve the electronic conductivity of the electrode, reduce the transmission resistance of electrons in the electrode, and thereby improve the power output of the battery. The carbon black particles can provide mechanical support for the active material, prevent stress from being generated in the electrode sheet during charging and discharging, enhance the structural stability of the electrode sheet, and reduce the mechanical stress caused by the volume expansion and contraction of the battery during charging and discharging.

[0050] Optionally, the carbon black particle size Dv50 of the second active material layer 2 can be, but is not limited to, 22 nm, 33 nm, 44 nm, 55 nm, 66 nm, 77 nm, 88 nm, 99 nm, 100 nm, 111 nm. The reason for setting the carbon black particle size Dv50 of the second active material layer 2 in this range is the same as the reason for setting the carbon black particle size of the first active material layer 1, and therefore will not be described again.

[0051] In an embodiment, when the first conductive agent and the second conductive agent both include graphene, the flake size of the graphene in the first active material layer 1 is larger than the flake size of the graphene in the second active material layer 2.

[0052] The use of large flake size graphene in the first active material layer 1 helps to improve the transmission efficiency and mechanical stability of electrons, while the use of small flake size graphene in the second active material layer 2 helps to increase the electrochemical reaction interface area and improve the ion diffusion efficiency.

[0053] In an embodiment, the graphene flake size of the first active material layer 1 is 2-10 μm; and / or, the graphene flake size of the second active material layer 2 is 0.1-1.5 μm. Optionally, the graphene flake size of the first active material layer 1 can be, but is not limited to, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm.

[0054] The graphene flake size of the first active material layer 1 in this range can form a continuous and efficient conductive network in the pole piece, reduce the internal resistance, thereby improving the transmission speed of electrons and the overall conductivity of the electrode, providing better mechanical support, improving the mechanical strength and deformation resistance of the pole piece, reducing the volume change of the active material, and improving the long-term cycle stability of the battery. The graphene flake can form a stable arrangement of connection points inside the electrode, forming a tight conductive network, providing a large number of active sites for electrochemical reactions, and improving the battery capacity.

[0055] Optionally, the graphene flake size of the second active material layer 2 can be, but is not limited to, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm. The reason for setting the graphene flake size of the second active material layer 2 in this range is the same as the reason for setting the graphene flake size of the first active material layer 1, so it is not repeated here.

[0056] In an embodiment, the first conductive agent and the second conductive agent further comprise carbon nanotubes, and the aspect ratio of the carbon nanotubes in the first active material layer 1 is greater than the aspect ratio of the carbon nanotubes in the second active material layer 2.

[0057] Carbon nanotubes with a larger aspect ratio can form a more efficient electron transmission network, providing a fast electron conduction path, so using carbon nanotubes with a larger aspect ratio in the first active material layer 1 can enhance the transmission capacity of electrons. Graphene with a larger flake size can form a more continuous and efficient electron transmission network, which helps to improve the conduction speed of electrons and the overall conductivity of the electrode.

[0058] In an embodiment, the aspect ratio of the carbon nanotubes in the first active material layer 1 is 500-800; and / or, the aspect ratio of the carbon nanotubes in the second active material layer 2 is 200-590. Optionally, the aspect ratio of the carbon nanotubes in the first active material layer 1 can be, but is not limited to, 500, 550, 600, 650, 700, 750, 800.

[0059] The aspect ratio of the carbon nanotubes of the first active material layer 1 in this range can provide longer continuous conductive paths, form an efficient conductive network, facilitate electron transport in the active material layer, provide support for the electrode material, enhance the mechanical stability of the electrode tab, reduce stress caused by volume changes during charging and discharging, thereby improving the cycle stability of the battery, increase the contact area of the active material with the electrolyte, increase the number of electrochemically active sites, form a porous structure, enhance ion transport in the electrode tab, form fewer agglomerates, and improve the uniformity and consistency of the active material.

[0060] Alternatively, the aspect ratio of the carbon nanotubes of the second active material layer 2 can be, but is not limited to, 200, 250, 300, 350, 400, 450, 500, 550, 590. The reason for setting the aspect ratio of the carbon nanotubes of the second active material layer 2 in this range is the same as that for setting the aspect ratio of the carbon nanotubes of the first active material layer 1, and therefore will not be described again.

[0061] In an embodiment, the first active material layer 1 includes first active material particles, and the second active material layer 2 includes second active material particles; the particle size Dv50 of the first active material particles is smaller than the particle size Dv50 of the second active material particles.

[0062] The first active material particles and the second active material particles can be lithium iron phosphate active material particles, ternary active material particles, lithium manganese acid active material particles, and lithium cobalt acid active material particles. The first active material particles and the second active material particles can also be graphite active material particles and lithium titanate active material particles. The particle size Dv50 of the first active material particles is smaller than the particle size Dv50 of the second active material particles. The contact area between the first active material particles with small particle size increases, a more compact conductive network can be formed, the path length of electron transport is reduced, the conductivity of electrons is improved, the conductivity of the first active material layer 1 near the current collector 3 is greater than that of the second active material layer 2 away from the current collector 3, the ability of one side of the current collector 3 to exchange electrons is improved, the impedance of the battery is reduced, and the performance of the battery is improved.

[0063] In an embodiment, the particle size Dv50 of the first active material particles is 0.01 μm-0.8 μm; and / or the particle size Dv50 of the second active material particles is 0.7 μm-1.5 μm. Alternatively, the particle size Dv50 of the first active material particles can be, but is not limited to, 0.01 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm.

[0064] When the particle size D50 of the first active material particles is within this range, the dispersibility of the first active material particles is good, agglomeration is prevented, a uniformly dispersed distribution is formed, the electrolyte can better penetrate into the electrode material, a more compact conductive network is formed, thereby improving the transmission efficiency of ions and electrons and improving the battery performance. The aspect ratio of the carbon nanotubes is high, which can span a long distance, thereby improving the connectivity of the entire conductive network, and through the synergistic effect with the first active material particles, the electrons can be quickly transmitted in the entire electrode. The carbon black provides a high specific surface area, so that the carbon black of a unit mass has more reaction surfaces, thereby increasing the contact area of the first active material particles and the electrolyte, thereby improving the ion transmission efficiency and the electrochemical reaction rate, and a more effective conductive network can be formed. The large sheet diameter of the graphene can form a continuous and efficient conductive network for the first active material particles in the electrode sheet, which can improve the transmission speed of electrons and the overall conductivity of the electrode.

[0065] Alternatively, the particle size Dv50 of the second active material particles can be, but is not limited to, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm. The reason for setting the particle size Dv50 of the second active material particles within this range is the same as that for setting the particle size Dv50 of the first active material particles, and thus will not be described again.

[0066] In an embodiment, the application provides a method for manufacturing the battery electrode sheet 10, as shown in FIG. 2, which includes the following steps:

[0067] S1, disposing a first active material layer on the current collector.

[0068] S2, disposing a second active material layer on the first active material layer.

[0069] Specifically, in the S1 step, the first active material layer includes carbon black and / or graphene. In the S2 step, the second active material layer includes carbon black and / or graphene. The carbon black and / or graphene in the first active material layer has a first shape size, the carbon black and / or graphene in the second active material layer has a second shape size, and the first shape size and the second shape size are different.

[0070] In an embodiment, the application provides a battery 20, which includes an electrolyte and the battery electrode sheet 10 of any one of the above embodiments or the battery electrode sheet 10 manufactured by the method for manufacturing the battery electrode sheet of the above embodiments, and the battery electrode sheet 10 is soaked in the electrolyte, as shown in FIG. 3.

[0071] In the battery 20, the battery pole piece 10 comprises a first active material layer 1 with high electronic conductivity and a second active material layer 2 with high ionic conductivity. Through the layered design, the first active material layer 1 close to the current collector 3 can quickly transport electrons, and the second active material layer 2 close to the electrolyte can quickly transport ions, optimizing the conduction of electrons and ions, thereby improving the performance of the battery.

[0072] In an embodiment, the application provides a power consuming device 30 comprising the battery 20 and the power consuming device 21 of the above embodiments, as shown in FIG. 4, the battery 20 supplies power to the power consuming device 21. The power consuming device 21 can include, but is not limited to, an electric energy storage device, an electric vehicle, a smartphone, and a notebook computer.

[0073] The application is further illustrated below in conjunction with the embodiments.

[0074] Embodiment 1

[0075] The embodiment provides a positive pole piece, which comprises a current collector, a first active material layer, and a second active material layer; the first active material layer is arranged on the current collector, and the second active material layer is arranged on the first active material layer.

[0076] The first active material layer comprises carbon black, carbon nanotubes, and graphene; the particle size Dv50 of the carbon black in the first active material layer is 7.94 nm; the aspect ratio of the carbon nanotubes in the first active material layer is 702; and the flake size of the graphene in the first active material layer is 6.3 μm. The second active material layer comprises carbon black, carbon nanotubes, and graphene; the particle size Dv50 of the carbon black in the second active material layer is 50.5 nm, the aspect ratio of the carbon nanotubes in the second active material layer is 320, and the flake size of the graphene in the second active material layer is 0.47 μm. The first active material particles in the first active material layer and the second active material particles in the second active material layer are both lithium iron phosphate particles. The particle size Dv50 of the first active material particles is 0.38 μm, and the particle size Dv50 of the second active material particles is 1.1 μm.

[0077] The manufacturing method of the positive pole piece of the embodiment is as follows:

[0078] Step 1, mix the first active material particles, the binder, the N-methyl-2-pyrrolidone solvent (NMP), and the conductive agent (carbon black, carbon nanotubes, and graphene) to prepare slurry A.

[0079] Step 2, mix the second active material particles, the binder, the N-methyl-2-pyrrolidone solvent (NMP), and the conductive agent (carbon black, carbon nanotubes, and graphene) to prepare slurry B.

[0080] Step 3, apply the slurry A obtained in step 1 on the aluminum foil and bake to obtain the first active material layer.

[0081] Step 4, the slurry B obtained in step 2 is coated on the first active material layer obtained in step 3, and baked to obtain a second active material layer.

[0082] The positive electrode sheet is baked and rolled to obtain.

[0083] Example 2

[0084] The positive electrode sheet includes a current collector, a first active material layer, and a second active material layer; the first active material layer is arranged on the current collector, and the second active material layer is arranged on the first active material layer.

[0085] The first active material layer includes carbon black and graphene; the particle size Dv50 of the carbon black in the first active material layer is 7.94 nm; and the flake size of the graphene in the first active material layer is 6.3 μm. The second active material layer includes carbon black and graphene; the particle size Dv50 of the carbon black in the second active material layer is 50.5 nm; and the flake size of the graphene in the second active material layer is 0.47 μm. The first active material particles in the first active material layer and the second active material particles in the second active material layer are both lithium iron phosphate particles. The particle size Dv50 of the first active material particles is 0.38 μm, and the particle size Dv50 of the second active material particles is 1.1 μm.

[0086] The difference between Example 2 and Example 1 is that no carbon nanotubes are added in Example 2.

[0087] The method for manufacturing the positive electrode sheet in Example 2 is the same as that in Example 1.

[0088] Example 3

[0089] The positive electrode sheet includes a current collector, a first active material layer, and a second active material layer; the first active material layer is arranged on the current collector, and the second active material layer is arranged on the first active material layer.

[0090] The first active material layer includes carbon nanotubes and graphene; the aspect ratio of the carbon nanotubes in the first active material layer is 702; and the flake size of the graphene in the first active material layer is 6.3 μm. The second active material layer includes carbon nanotubes and graphene; the aspect ratio of the carbon nanotubes in the second active material layer is 320; and the flake size of the graphene in the second active material layer is 0.47 μm. The first active material particles in the first active material layer and the second active material particles in the second active material layer are both lithium iron phosphate particles. The particle size Dv50 of the first active material particles is 0.38 μm, and the particle size Dv50 of the second active material particles is 1.1 μm.

[0091] The difference between Example 3 and Example 1 is that no carbon black is added in Example 3.

[0092] The manufacturing method of the positive electrode sheet in Example 3 is the same as that in Example 1.

[0093] Example 4

[0094] The present example provides a positive electrode sheet, the positive electrode sheet comprising a current collector, a first active material layer, and a second active material layer; the first active material layer is disposed on the current collector, and the second active material layer is disposed on the first active material layer.

[0095] The first active material layer comprises carbon black and carbon nanotubes; the particle size Dv50 of the carbon black in the first active material layer is 7.94 nm; and the aspect ratio of the carbon nanotubes in the first active material layer is 702. The second active material layer comprises carbon black and carbon nanotubes; the particle size Dv50 of the carbon black in the second active material layer is 50.5 nm, and the aspect ratio of the carbon nanotubes in the second active material layer is 320. The first active material particles in the first active material layer and the second active material particles in the second active material layer are both lithium iron phosphate particles. The particle size Dv50 of the first active material particles is 0.38 μm, and the particle size Dv50 of the second active material particles is 1.1 μm.

[0096] The difference between Example 4 and Example 1 is that no graphene is added in Example 4.

[0097] The manufacturing method of the positive electrode sheet in Example 4 is the same as that in Example 1.

[0098] Example 5

[0099] The present example provides a positive electrode sheet, the positive electrode sheet comprising a current collector, a first active material layer, and a second active material layer; the first active material layer is disposed on the current collector, and the second active material layer is disposed on the first active material layer.

[0100] The first active material layer comprises carbon black; the particle size Dv50 of the carbon black in the first active material layer is 7.94 nm. The second active material layer comprises carbon black; the particle size Dv50 of the carbon black in the second active material layer is 50.5 nm. The first active material particles in the first active material layer and the second active material particles in the second active material layer are both lithium iron phosphate particles. The particle size Dv50 of the first active material particles is 0.38 μm, and the particle size Dv50 of the second active material particles is 1.1 μm.

[0101] The difference between Example 5 and Example 1 is that only carbon black is added in Example 5.

[0102] The manufacturing method of the positive electrode sheet in Example 5 is the same as that in Example 1.

[0103] Example 6

[0104] The embodiment provides a positive electrode sheet, the positive electrode sheet comprising a current collector, a first active material layer and a second active material layer; the first active material layer is arranged on the current collector, and the second active material layer is arranged on the first active material layer.

[0105] The first active material layer comprises graphene, and the graphene flake diameter of the first active material layer is 6.3 μm. The second active material layer comprises graphene, and the graphene flake diameter of the second active material layer is 0.47 μm. The first active material particles in the first active material layer and the second active material particles in the second active material layer are both lithium iron phosphate particles. The particle size Dv50 of the first active material particles is 0.38 μm, and the particle size Dv50 of the second active material particles is 1.1 μm.

[0106] The difference between the embodiment 6 and the embodiment 1 is that only graphene is added in the embodiment 6.

[0107] The manufacturing method of the positive electrode sheet in the embodiment 6 is the same as that in the embodiment 1.

[0108] Embodiment 7

[0109] The embodiment provides a positive electrode sheet, the positive electrode sheet comprising a current collector, a first active material layer and a second active material layer; the first active material layer is arranged on the current collector, and the second active material layer is arranged on the first active material layer.

[0110] The first active material layer comprises carbon black, carbon nanotubes and graphene; the particle size Dv50 of the carbon black in the first active material layer is 6.3 nm; the aspect ratio of the carbon nanotubes in the first active material layer is 702; and the graphene flake diameter of the first active material layer is 6.3 μm. The second active material layer comprises carbon black, carbon nanotubes and graphene; the particle size Dv50 of the carbon black in the second active material layer is 22 nm, the aspect ratio of the carbon nanotubes in the second active material layer is 320, and the graphene flake diameter of the second active material layer is 0.47 μm. The first active material particles in the first active material layer and the second active material particles in the second active material layer are both lithium iron phosphate particles. The particle size Dv50 of the first active material particles is 0.38 μm, and the particle size Dv50 of the second active material particles is 1.1 μm.

[0111] The difference between the embodiment 7 and the embodiment 1 is that the carbon black particle size in the first active material layer and the second active material layer is changed in the embodiment 7.

[0112] The manufacturing method of the positive electrode sheet in the embodiment 7 is the same as that in the embodiment 1.

[0113] Embodiment 8

[0114] The embodiment provides a positive electrode sheet, the positive electrode sheet comprising a current collector, a first active material layer and a second active material layer; the first active material layer is arranged on the current collector, and the second active material layer is arranged on the first active material layer.

[0115] The first active material layer comprises carbon black, carbon nanotubes and graphene; the particle size Dv50 of the carbon black in the first active material layer is 14.8 nm; the aspect ratio of the carbon nanotubes in the first active material layer is 702; and the flake size of the graphene in the first active material layer is 6.3 μm. The second active material layer comprises carbon black, carbon nanotubes and graphene; the particle size Dv50 of the carbon black in the second active material layer is 111 nm, the aspect ratio of the carbon nanotubes in the second active material layer is 320, and the flake size of the graphene in the second active material layer is 0.47 μm. The first active material particles in the first active material layer and the second active material particles in the second active material layer are both lithium iron phosphate particles. The particle size Dv50 of the first active material particles is 0.38 μm, and the particle size Dv50 of the second active material particles is 1.1 μm.

[0116] The difference between example 8 and example 1 is that the particle size of the carbon black in the first active material layer and the second active material layer is changed in example 8.

[0117] The manufacturing method of the positive electrode sheet in example 8 is the same as that in example 1.

[0118] Example 9

[0119] The embodiment provides a positive electrode sheet, the positive electrode sheet comprising a current collector, a first active material layer and a second active material layer; the first active material layer is arranged on the current collector, and the second active material layer is arranged on the first active material layer.

[0120] The first active material layer comprises carbon black, carbon nanotubes and graphene; the particle size Dv50 of the carbon black in the first active material layer is 7.94 nm; the aspect ratio of the carbon nanotubes in the first active material layer is 702; and the flake size of the graphene in the first active material layer is 2 μm. The second active material layer comprises carbon black, carbon nanotubes and graphene; the particle size Dv50 of the carbon black in the second active material layer is 50.5 nm, the aspect ratio of the carbon nanotubes in the second active material layer is 320, and the flake size of the graphene in the second active material layer is 0.1 μm. The first active material particles in the first active material layer and the second active material particles in the second active material layer are both lithium iron phosphate particles. The particle size Dv50 of the first active material particles is 0.38 μm, and the particle size Dv50 of the second active material particles is 1.1 μm.

[0121] The difference between example 9 and example 1 is that the flake size of the graphene in the first active material layer and the second active material layer is changed in example 9.

[0122] The manufacturing method of the positive electrode sheet in example 9 is the same as that in example 1.

[0123] Example 10

[0124] The example provides a positive electrode sheet, the positive electrode sheet comprising a current collector, a first active material layer and a second active material layer; the first active material layer is disposed on the current collector, and the second active material layer is disposed on the first active material layer.

[0125] The first active material layer comprises carbon black, carbon nanotubes and graphene; the particle size Dv50 of the carbon black in the first active material layer is 7.94 nm; the aspect ratio of the carbon nanotubes in the first active material layer is 702; and the flake size of the graphene in the first active material layer is 10 μm. The second active material layer comprises carbon black, carbon nanotubes and graphene; the particle size Dv50 of the carbon black in the second active material layer is 50.5 nm, the aspect ratio of the carbon nanotubes in the second active material layer is 320, and the flake size of the graphene in the second active material layer is 1.5 μm. The first active material particles in the first active material layer and the second active material particles in the second active material layer are both lithium iron phosphate particles. The particle size Dv50 of the first active material particles is 0.38 μm, and the particle size Dv50 of the second active material particles is 1.1 μm.

[0126] The difference between Example 10 and Example 1 is that the flake size of the graphene in the first active material layer and the second active material layer is changed in Example 10.

[0127] The method for manufacturing the positive electrode sheet in Example 10 is the same as that in Example 1.

[0128] Example 11

[0129] The example provides a positive electrode sheet, the positive electrode sheet comprising a current collector, a first active material layer and a second active material layer; the first active material layer is disposed on the current collector, and the second active material layer is disposed on the first active material layer.

[0130] The first active material layer comprises carbon black, carbon nanotubes and graphene; the particle size D50 of the carbon black in the first active material layer is 7.94 nm; the aspect ratio of the carbon nanotubes in the first active material layer is 500; and the flake size of the graphene in the first active material layer is 6.3 μm. The second active material layer comprises carbon black, carbon nanotubes and graphene; the particle size D50 of the carbon black in the second active material layer is 50.5 nm, the aspect ratio of the carbon nanotubes in the second active material layer is 200, and the flake size of the graphene in the second active material layer is 0.47 μm. The first active material particles in the first active material layer and the second active material particles in the second active material layer are both lithium iron phosphate particles. The particle size D50 of the first active material particles is 0.38 μm, and the particle size D50 of the second active material particles is 1.1 μm.

[0131] Example 11 and Example 1 differ in that the aspect ratio of the carbon nanotubes in the first active material layer and the second active material layer is changed in Example 11.

[0132] The method of manufacturing the positive electrode sheet in Example 11 is the same as that in Example 1.

[0133] Example 12

[0134] The present embodiment provides a positive electrode sheet, the positive electrode sheet comprising a current collector, a first active material layer and a second active material layer; the first active material layer is disposed on the current collector, and the second active material layer is disposed on the first active material layer.

[0135] The first active material layer comprises carbon black, carbon nanotubes and graphene; the particle size D50 of the carbon black in the first active material layer is 7.94 nm; the aspect ratio of the carbon nanotubes in the first active material layer is 800; and the flake size of the graphene in the first active material layer is 6.3 μm. The second active material layer comprises carbon black, carbon nanotubes and graphene; the particle size D50 of the carbon black in the second active material layer is 50.5 nm, the aspect ratio of the carbon nanotubes in the second active material layer is 590, and the flake size of the graphene in the second active material layer is 0.47 μm. The first active material particles in the first active material layer and the second active material particles in the second active material layer are both lithium iron phosphate particles. The particle size D50 of the first active material particles is 0.38 μm, and the particle size D50 of the second active material particles is 1.1 μm.

[0136] Example 12 and Example 1 differ in that the aspect ratio of the carbon nanotubes in the first active material layer and the second active material layer is changed in Example 12.

[0137] The method of manufacturing the positive electrode sheet in Example 12 is the same as that in Example 1.

[0138] Example 13

[0139] The present embodiment provides a positive electrode sheet, the positive electrode sheet comprising a current collector, a first active material layer and a second active material layer; the first active material layer is disposed on the current collector, and the second active material layer is disposed on the first active material layer.

[0140] The first active material layer includes carbon black, carbon nanotubes and graphene; the particle size Dv50 of the carbon black in the first active material layer is 7.94 nm; the aspect ratio of the carbon nanotubes in the first active material layer is 702; and the flake size of the graphene in the first active material layer is 6.3 μm. The second active material layer includes carbon black, carbon nanotubes and graphene; the particle size Dv50 of the carbon black in the second active material layer is 50.5 nm, the aspect ratio of the carbon nanotubes in the second active material layer is 320, and the flake size of the graphene in the second active material layer is 0.47 μm. The first active material particles in the first active material layer and the second active material particles in the second active material layer are both lithium iron phosphate particles. The particle size Dv50 of the first active material particles is 0.8 μm, and the particle size Dv50 of the second active material particles is 1.1 μm.

[0141] Example 13 differs from Example 1 in that the particle size Dv50 of the first active material particles is changed in Example 13.

[0142] The method for manufacturing the positive electrode sheet in Example 13 is the same as that in Example 1.

[0143] Example 14

[0144] The present embodiment provides a positive electrode sheet, which includes a current collector, a first active material layer and a second active material layer; the first active material layer is arranged on the current collector, and the second active material layer is arranged on the first active material layer.

[0145] The first active material layer includes carbon black, carbon nanotubes and graphene; the particle size Dv50 of the carbon black in the first active material layer is 7.94 nm; the aspect ratio of the carbon nanotubes in the first active material layer is 702; and the flake size of the graphene in the first active material layer is 6.3 μm. The second active material layer includes carbon black, carbon nanotubes and graphene; the particle size Dv50 of the carbon black in the second active material layer is 50.5 nm, the aspect ratio of the carbon nanotubes in the second active material layer is 320, and the flake size of the graphene in the second active material layer is 0.47 μm. The first active material particles in the first active material layer and the second active material particles in the second active material layer are both lithium iron phosphate particles. The particle size Dv50 of the first active material particles is 0.38 μm, and the particle size Dv50 of the second active material particles is 0.7 μm.

[0146] Example 14 differs from Example 1 in that the particle size Dv50 of the second active material particles is changed in Example 14.

[0147] The method for manufacturing the positive electrode sheet in Example 14 is the same as that in Example 1.

[0148] Comparative Example 1

[0149] The present embodiment provides a positive electrode sheet, which includes a current collector and a first active material layer; the first active material layer is arranged on the current collector.

[0150] The first active material layer includes carbon black, carbon nanotubes, and graphene; the particle size Dv50 of the carbon black of the first active material layer is 7.94 nm; the aspect ratio of the carbon nanotubes of the first active material layer is 702; and the flake size of the graphene of the first active material layer is 6.3 μm. The first active material particles in the first active material layer are lithium iron phosphate particles. The particle size Dv50 of the first active material particles is 0.38 μm.

[0151] The difference between Comparative Example 1 and Example 1 is that only one active material layer is provided in Comparative Example 1.

[0152] The manufacturing method of the positive electrode sheet in Comparative Example 1 is the same as that in Example 1.

[0153] Comparative Example 2

[0154] The present embodiment provides a positive electrode sheet, which includes a current collector, a first active material layer, and a second active material layer; the second active material layer is arranged on the current collector, and the first active material layer is arranged on the second active material layer.

[0155] The first active material layer includes carbon black, carbon nanotubes, and graphene; the particle size Dv50 of the carbon black of the first active material layer is 7.94 nm; the aspect ratio of the carbon nanotubes of the first active material layer is 702; and the flake size of the graphene of the first active material layer is 6.3 μm. The second active material layer includes carbon black, carbon nanotubes, and graphene; the particle size Dv50 of the carbon black of the second active material layer is 7.94 nm, the aspect ratio of the carbon nanotubes of the second active material layer is 702, and the flake size of the graphene of the second active material layer is 6.3 μm. The first active material particles in the first active material layer and the second active material particles of the second active material layer are both lithium iron phosphate particles. The particle size Dv50 of the first active material particles is 0.38 μm, and the particle size Dv50 of the second active material particles is 1.1 μm.

[0156] The difference between Comparative Example 2 and Example 1 is that the first shape size of the first conductive agent and the second shape size of the second conductive agent are the same in Comparative Example 2.

[0157] The manufacturing method of the positive electrode sheet in Comparative Example 2 is the same as that in Example 1.

[0158] Comparative Example 3

[0159] The present embodiment provides a positive electrode sheet, which includes a current collector, a first active material layer, and a second active material layer; the first active material layer is arranged on the current collector, and the second active material layer is arranged on the first active material layer.

[0160] The first active material layer and the second active material layer are both conductive graphite. The first active material particles in the first active material layer and the second active material particles in the second active material layer are both lithium iron phosphate particles. The particle size Dv50 of the first active material particles is 0.38 μm, and the particle size Dv50 of the second active material particles is 1.1 μm.

[0161] The difference between Comparative Example 3 and Example 1 is that neither the first active material layer nor the second active material layer in Comparative Example 3 includes any of carbon black, carbon nanotubes, and graphene.

[0162] The production method of the positive electrode sheet in Comparative Example 3 is the same as that in Example 1.

[0163] The positive electrode sheets provided in Examples 1-14 and Comparative Examples 1-3 are assembled with negative electrode sheets to form soft package batteries, wherein the negative electrode sheets are graphite negative electrode sheets.

[0164] Test method:

[0165] (1) Longitudinal resistivity of electrode sheet

[0166] The above electrode sheet is pressed with uniform and stable pressure on the electrode sheet longitudinal resistivity tester, and a constant current is longitudinally passed through the electrode sheet, the voltage drop is measured, and the resistivity is obtained.

[0167] (2) Liquid phase diffusion impedance of electrode sheet

[0168] The above battery electrode sheet and electrolyte are taken to assemble a battery cell. The parameters of EIS test are set on an electrochemical workstation, a small amplitude sinusoidal potential disturbance or current disturbance is applied, and the response of the battery is measured. The collected data is used to construct Nyquist and Bode plots, and then an equivalent circuit model is selected or designed to fit the experimental data to determine the parameter value of the liquid phase diffusion impedance.

[0169] (3) Mixing gram capacity

[0170] After the above battery is charged at 0.1C constant current to the upper limit voltage 4.2V, it is charged at constant voltage to the current decreased to 0.03C, and then rested for 5 minutes. The battery is discharged at 0.1C constant current to the lower limit cutoff voltage 2.0V. The charge and discharge current values are changed to complete the test of 0.2C and 0.5C current values.

[0171] Wherein, gram capacity = actual capacity of battery / (mass of electrode sheet - mass of current collector)

[0172] (4) DCIR test:

[0173] The above battery was discharged at 1 / 3C constant current to 2.0V at room temperature, charged at 1 / 3C constant current to 50% SOC, discharged at 1.5C constant current for 30s at 25°C and -10°C respectively, and the voltage before and after discharge was recorded to calculate the discharge DCIR. Among them, DCIR (mΩ) = (voltage before discharge-voltage after discharge) / discharge current*1000.

[0174] The results are shown in Table 1.

[0175] Table 1

[0176] Compared with Comparative Examples 1-3 and Examples 1-14, in Table 1, the electrode strip longitudinal resistivity, electrode strip liquid phase diffusion impedance, mixture gram capacity and DCIR of Examples 1-14 are all better than those of Comparative Examples 1-3. Examples 1-14 are provided with double-layer active material layers, the electronic conductivity of the first active material layer is high, the ionic conductivity of the second active material layer is high, and at least one of carbon black and graphene is added; the carbon black particle size Dv50 in the first active material layer is smaller than the carbon black particle size Dv50 in the second active material layer, the flake size of graphene in the first active material layer is larger than the flake size of graphene in the second active material layer, the ion transmission channel and the conductive network in the electrode strip are optimized, thereby improving the performance of the electrode strip and the battery.

[0177] Compared with Example 1 and Examples 2-6, in Table 1, the electrode strip longitudinal resistivity, electrode strip liquid phase diffusion impedance, mixture gram capacity and DCIR of Example 1 are all better than those of Examples 2-6. By adding carbon black, carbon nanotubes and graphene, and through the combined action of carbon black, carbon nanotubes and graphene, the ion transmission channel and the conductive network in the electrode strip are optimized in Example 1, thereby improving the performance.

[0178] Compared with Example 1 and Examples 7-14, in Table 1, the electrode strip longitudinal resistivity, electrode strip liquid phase diffusion impedance, mixture gram capacity and DCIR of Example 1 are all better than those of Examples 7-14. The carbon black particle size Dv50 in the first active material layer of Example 1 is smaller than the carbon black particle size Dv50 in the second active material layer, the aspect ratio of carbon nanotubes in the first active material layer is larger than the aspect ratio of carbon nanotubes in the second active material layer, the flake size of graphene in the first active material layer is larger than the flake size of graphene in the second active material layer, the ion transmission channel and the conductive network in the electrode strip are optimized, better electronic and ionic transmission performance is provided, thereby improving the performance of the electrode strip and the battery.

[0179] In the description of the embodiments of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like, indicate the orientation or positional relationship based on the drawings described in the application, and 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 particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0180] The above only discloses a preferred embodiment of the present application, of course cannot limit the scope of the present application, those skilled in the art can understand that the implementation of all or part of the above-mentioned process, and the equivalent changes made by the claims of the present application, still belong to the scope covered by the present application.

Claims

1. A battery electrode sheet (10) characterized by, comprise carbon black and / or graphene; and the second active material layer (2) is provided on a side of the first active material layer (1) facing away from the current collector (3), the second active material layer (2) comprising a second conductive agent, the second conductive agent comprising carbon black and / or graphene; the first conductive agent has a first shape size, the second conductive agent has a second shape size, the first shape size and the second shape size being different. when the first conductive agent and the second conductive agent both comprise carbon black, a carbon black particle size Dv50 in the first active material layer (1) is smaller than a carbon black particle size Dv50 in the second active material layer (2); when the first conductive agent and the second conductive agent both comprise graphene, a graphene flake size in the first active material layer (1) is larger than a graphene flake size in the second active material layer (2).

2. The battery pole piece (10) according to claim 1, characterized in that 3. The battery pole piece (10) according to claim 1 or 2, characterized in that when the first conductive agent comprises carbon black, a carbon black particle size Dv50 in the first active material layer (1) is 6.3 nm-14.8 nm; when the second conductive agent comprises carbon black, a carbon black particle size Dv50 in the second active material layer (2) is 22 nm-111 nm; when the first conductive agent comprises graphene, a graphene flake size in the first active material layer (1) is 2 μm-10 μm; when the second conductive agent comprises graphene, a graphene flake size in the second active material layer (2) is 0.1 μm-1.5 μm. the first conductive agent and the second conductive agent further comprise carbon nanotubes. a carbon nanotube aspect ratio in the first active material layer (1) is larger than a carbon nanotube aspect ratio in the second active material layer (2).

4. The battery pole piece (10) according to any one of claims 1-3, characterized in that, 6. The battery pole piece (10) according to claim 4 or 5, characterized in that 5. The battery pole piece (10) according to claim 4, characterized in that a carbon nanotube aspect ratio in the first active material layer (1) is 500-800; and / or a carbon nanotube aspect ratio in the second active material layer (2) is 200-590. the first active material layer (1) comprises first active material particles, the second active material layer (2) comprises second active material particles; a particle size Dv50 of the first active material particles is smaller than a particle size Dv50 of the second active material particles.

8. The battery pole piece (10) according to claim 7, characterized in that 7. The battery pole piece (10) according to any one of claims 1-6, characterized in that, a particle size Dv50 of the first active material particles is 0.01 μm-0.8 μm; and / or a particle size Dv50 of the second active material particles is 0.7 μm-1.5 μm. comprise an electrolyte; and the battery pole piece (10) according to any one of claims 1-8 is soaked in the electrolyte.

9. A battery (20) characterized by, comprise a battery (20) according to claim 9; and comprise ​ ​ 10. An electrical device (30) characterized by ​ ​ ​ An electric device (21) is powered by the battery (20).

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