Battery pole piece, preparation method thereof and battery

Abstract

The invention discloses a battery pole piece, a preparation method thereof and a battery, relates to the technical field of batteries, and aims to solve the problem that the internal pressure of the battery is large due to the fact that the battery generates gas in circulation and storage processes. The battery pole piece comprises a current collector, a tab and a material layer, the tab is arranged on one side of the current collector along the first direction; the first direction intersects with the thickness direction of the battery pole piece. The material layer includes an electrode active material layer and at least one gas absorbing layer. The electrode active material layer is arranged on at least one side of the current collector along the second direction. The at least one gas absorption layer is arranged on at least one side of the electrode active material layer along the first direction, and the at least one gas absorption layer and the electrode active material layer are arranged on the same side of the current collector. The second direction is the thickness direction of the battery pole piece. The material of the gas absorption layer comprises a porous material and an insulating material.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery pole piece, a preparation method thereof, and a battery. Background Art

[0002] Batteries produce gas during the cycle and storage process, which will increase the internal pressure of the battery, cause battery volume expansion, electrode / diaphragm misalignment, and increase battery polarization, resulting in a decrease in battery life and even safety problems. Summary of the Invention

[0003] The purpose of this application is to provide a battery electrode and a preparation method thereof, and a battery, aiming to solve the problem that the battery produces gas during circulation and storage, resulting in high internal pressure of the battery.

[0004] To achieve the above objectives, this application adopts the following technical solutions:

[0005] In a first aspect, an embodiment of the present application provides a battery electrode sheet, comprising: a current collector, a tab, and a material layer. The tab is provided on one side of the current collector along a first direction. The first direction intersects with the thickness direction of the battery electrode sheet. The material layer comprises an electrode active material layer and at least one gas absorption layer. The electrode active material layer is provided on at least one side of the current collector along a second direction. At least one gas absorption layer is provided on at least one side of the electrode active material layer along the first direction, and is provided on the same side of the current collector as the electrode active material layer. The second direction is the thickness direction of the battery electrode sheet. The material of the gas absorption layer comprises: a porous material and an insulating material.

[0006] In the battery electrode provided in the embodiments of the present application, the gas absorption layer can absorb gas diffused from the electrode active material layer, shortening the gas diffusion path. It can also absorb gas generated by electrolyte decomposition, release of reactive oxygen gases from electrode materials, and decomposition of solid electrolyte interface membranes, preventing the formation of bubbles inside the battery and the generation of brown spots. Furthermore, the gas absorption layer is located on one side of the electrode active material layer, without hindering the movement of active ions, allowing the movement of active ions to proceed normally. The gas absorption layer, through its porous structure and adsorption capacity, can effectively absorb gas, reducing the internal pressure of the battery, thereby alleviating or eliminating problems such as battery volume expansion, electrode / diaphragm misalignment, and increased battery polarization.

[0007] In some embodiments, the porous material comprises at least one of a MOF material, activated carbon, alkali metal alcoholate, alumina, biochar, silicon carbide, activated calcium oxide, a bio-based material, and activated silica gel.

[0008] In some embodiments, the MOF material includes a matrix and functional groups. The MOF matrix includes at least one of an iron group, a magnesium group, a manganese group, and an aluminum group. The functional groups include at least one of a sulfonate group, an amino group, a carboxylic acid group, a sulfide group, an amine group, a nitrogen group, a hydroxyl group, a thiol group, an aldehyde group, and a methyl group.

[0009] In some embodiments, the MOF material includes at least one of Fe-MOF, MOF-5, ZIF-8, UiO-66, MIL-101, and HKUST-1.

[0010] In some embodiments, the insulating material includes a ceramic material.

[0011] In some embodiments, the porous material and the insulating material are coordinately connected and / or the porous material and the insulating material are physically mixed.

[0012] In some embodiments, the ratio of the mass of the porous material to the total mass of the material of the gas absorbing layer is in the range of 0.1 to 0.5.

[0013] In some embodiments, there are multiple gas absorption layers, one of which is disposed on a side of the electrode active material layer close to the tab, and at least one gas absorption layer is disposed on a side of the electrode active material layer away from the tab.

[0014] In some embodiments, a battery electrode sheet includes: a first electrode sheet and a second electrode sheet. The gas absorption layer provided on one side of the first electrode sheet is a first sub-absorption layer. The gas absorption layer provided on one side of the second electrode sheet is a second sub-absorption layer. The dimension of the first sub-absorption layer along a first direction is greater than or equal to the dimension of the second sub-absorption layer along the first direction. The first direction intersects the thickness direction of the battery electrode sheet.

[0015] In some embodiments, the gas absorption layer disposed on the side of the electrode active material layer close to the tab is a third sub-absorption layer. The gas absorption layer disposed on the side of the electrode active material layer away from the tab is a fourth sub-absorption layer. The dimension of the third sub-absorption layer along the first direction is greater than or equal to the dimension of the fourth sub-absorption layer along the first direction.

[0016] In some embodiments, a dimension of the gas absorption layer along the second direction ranges from 100 μm to 150 μm.

[0017] In a second aspect, embodiments of the present application provide a method for manufacturing a battery electrode sheet. The method includes providing a current collector. A tab is formed on one side of the current collector along a first direction, the tab being disposed on the side of the current collector along the first direction. The first direction intersects the thickness direction of the battery electrode sheet.

[0018] A material layer is formed on at least one side of the current collector along the second direction. The material layer includes an electrode active material layer and at least one gas absorption layer. The electrode active material layer is disposed on at least one side of the current collector along the second direction. The at least one gas absorption layer is disposed on at least one side of the electrode active material layer along the first direction, on the same side of the current collector as the electrode active material layer. The second direction is the thickness direction of the battery electrode sheet. The gas absorption layer comprises a porous material and an insulating material.

[0019] In some embodiments, forming a material layer on at least one side of the current collector along the second direction includes: forming at least one gas absorption layer;

[0020] The forming of at least one gas absorption layer comprises at least one of the following methods:

[0021] Mixing a porous material and an insulating material, and coating the mixture on at least one side of the current collector along the second direction to form a gas absorption layer;

[0022] Coating a porous material on at least one side of the current collector along the second direction, and coating an insulating material on a side of the porous material away from the current collector to form a gas absorption layer;

[0023] An insulating material is coated on at least one side of the current collector along the second direction, and a porous material is coated on a side of the insulating material away from the current collector to form a gas absorption layer.

[0024] In a third aspect, embodiments of the present application provide a battery comprising: a separator and a battery electrode as described in any of the above embodiments.

[0025] It can be understood that the beneficial effects achieved by the method for preparing the battery pole piece and the battery provided in the above embodiments of the present application can be referred to the beneficial effects of the battery pole piece described above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0027] Figure 1 A schematic diagram of a battery in some embodiments of the present application;

[0028] Figure 2 This is a schematic diagram of a battery electrode in some embodiments of the present application;

[0029] Figure 3A Another schematic diagram of a battery electrode in some embodiments of the present application;

[0030] Figure 3B This is another schematic diagram of a battery electrode in some embodiments of the present application;

[0031] Figure 4A This is another schematic diagram of a battery electrode in some embodiments of the present application;

[0032] Figure 4B This is another schematic diagram of a battery electrode in some embodiments of the present application;

[0033] Figure 5A This is another schematic diagram of a battery electrode in some embodiments of the present application;

[0034] Figure 5B This is another schematic diagram of a battery electrode in some embodiments of the present application;

[0035] Figure 6 This is another schematic diagram of a battery electrode in some embodiments of the present application;

[0036] Figure 7 This is a flow chart of a method for preparing a battery electrode in some embodiments of the present application. DETAILED DESCRIPTION

[0037] 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 in 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.

[0038] In the description of this application, it should be understood that the terms "upper," "lower," "left," "right," "front," "back," "inner," "outer," and the like, indicating directions or positional relationships, are based on the directions or relative positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific direction, be constructed, or operate in a specific direction. Therefore, they should not be construed as limitations on this application. Unless otherwise specified, the above-mentioned directionality descriptions may be flexibly set in actual application, provided that the relative positional relationships shown in the accompanying drawings are met.

[0039] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout this application, unless otherwise specified, "plurality" means two or more.

[0040] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections. They may be directly connected, indirectly connected through an intermediary, or internally connected between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0041] In the embodiments of the present application, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, article, or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of other identical elements in the process, article, or device comprising the element.

[0042] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0043] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0044] like Figure 1 As shown, the working process of the battery is that active ions (such as lithium ions in a lithium-ion battery) reversibly migrate between the battery pole pieces 1 through the electrolyte 3 and the separator 2, thereby achieving energy storage and release. In addition, the active ions are released from / embedded into the electrode material on the battery pole pieces 1, completing the repeated cycle of the battery from the charging state to the discharging state and then back to the charging state.

[0045] In some embodiments, as Figure 1 As shown, a battery is provided, which includes: a separator 2 and a battery electrode 1.

[0046] Exemplarily, the battery electrode 1 includes a positive electrode and a negative electrode.

[0047] Batteries produce gases 4 during cycling and storage, including redox reactions in the electrolyte 3, decomposition of residues formed during the preparation and storage of electrode materials, residual moisture and its side reactions caused by insufficient drying, crosstalk reactions, decomposition of the solid electrolyte phase interface film (a protective film formed when the battery is first charged and discharged), and release of active oxygen by electrode materials at high temperatures. These processes will produce a variety of gases 4, such as hydrogen (H2), oxygen (O2), olefins, alkanes, carbon dioxide (CO2), and carbon monoxide (CO).

[0048] These gases 4 will move continuously along the gap between the electrolyte and the battery electrode 1 or the space inside the battery shell, and then gather inside the battery, causing the internal pressure of the battery to increase, and then causing the battery volume to expand. It may also cause misalignment between the battery electrode 1 and the diaphragm 2, destroying the structural integrity of the battery, and causing the battery polarization to increase, that is, the internal resistance of the battery to increase, which will reduce the battery's charge and discharge efficiency and accelerate capacity decay.

[0049] In extreme cases, the generation of Gas 4 can also cause safety issues. For example, when the internal pressure of the battery is too high, the battery may swell or even rupture, leading to electrolyte leakage and fire risk. Furthermore, the generation of Gas 4 can trigger thermal runaway reactions within the battery, further exacerbating the battery's temperature rise and gas generation, forming a vicious cycle that can ultimately lead to battery explosion.

[0050] Therefore, it is particularly important to absorb the gas 4 generated in the battery to reduce the internal pressure of the battery.

[0051] Based on this, firstly, Figure 2 and Figure 6 As shown, an embodiment of the present application provides a battery electrode 1, comprising: a current collector 10, a tab 30 and a material layer 20.

[0052] The current collector 10 is mainly used to collect and conduct current. The current collector 10 provides a stable support structure for the material layer 20 and ensures that the current can be efficiently transmitted to the external circuit. In the battery, the material of the current collector 10 is a material with good conductivity.

[0053] For example, the material of the current collector 10 of the positive electrode sheet can be aluminum foil.

[0054] For example, the material of the current collector 10 of the negative electrode plate can be copper foil.

[0055] The tab 30 is provided on one side of the current collector 10 along a first direction X. The first direction X intersects with the thickness direction of the battery electrode 1 .

[0056] The tab 30 is a metal sheet or ribbon that connects the current collector 10 to an external circuit (such as a battery management system or a load). The tab 30 is directly connected to the current collector 10 to conduct current out of the battery.

[0057] The material layer 20 includes an electrode active material layer 21 and at least one gas absorption layer 22. The electrode active material layer 21 is disposed on at least one side of the current collector 10 along the second direction Y. The at least one gas absorption layer 22 is disposed on at least one side of the electrode active material layer 21 along the first direction X, and is disposed on the same side of the current collector 10 as the electrode active material layer 21. The second direction Y is the thickness direction of the battery electrode sheet.

[0058] Exemplarily, the battery electrode 1 is divided into a first electrode 11 and a second electrode 12. The first electrode 11 is one of the positive electrode and the negative electrode, and the second electrode 12 is the other of the positive electrode and the negative electrode. In the embodiment of the present application, the first electrode 11 is a positive electrode and the second electrode 12 is a negative electrode.

[0059] The electrode active material layer 21 of the first pole piece 11 is a positive electrode active material, such as lithium iron phosphate, lithium iron manganese phosphate, lithium nickel cobalt manganese oxide, lithium nickel manganese oxide, lithium manganese oxide, or a lithium-rich manganese matrix. The electrode active material layer 21 of the second pole piece 12 is a negative electrode active material, such as a carbon negative electrode material, an alloy negative electrode material, a compound negative electrode material, or other novel negative electrode materials.

[0060] The electrode active material layer 21 can store and release active ions. During charging, the active ions are embedded into the electrode active material layer 21 from the electrolyte 3; during discharging, the active ions are released from the electrode active material layer 21 and returned to the electrolyte 3.

[0061] The gas absorption layer 22 is a special layer that absorbs the gas 4 generated inside the battery. Here, the gas absorption layer 22 can be provided on the surface of the current collector 10, or on the surface of the current collector 10 and the tab 30, or on the welding area Q between the current collector 10 and the tab 30 (e.g., Figure 6 The gas absorption layer 22 may be connected to the electrode active material layer 21, or the gas absorption layer 22 may be spaced apart from the electrode active material layer 21; the gas absorption layer 22 may be disposed on a side of the electrode active material layer 21 close to the electrode tab 30, or on a side of the electrode active material layer 21 away from the electrode tab 30.

[0062] The material of the gas absorption layer 22 includes porous material and insulating material.

[0063] The porous material of gas absorption layer 22 provides a large number of pores, which gives it a large surface area for efficient absorption of gas 4. The insulating material ensures the electrical insulation of gas absorption layer 22 within the battery, reducing the risk of tab 30 bending and contacting current collector 10, effectively addressing the safety issue of short circuits. The gas absorption layer 22 formed by the porous and insulating materials increases the voids in the insulating material, increasing its specific surface area and improving its adsorption performance, thus expanding the insulating material's functionality.

[0064] Through the above-described arrangement, the gas absorption layer 22 can directly absorb the gas 4 generated from the electrode active material layer 21, the gas 4 decomposed from the electrolyte 3, and the gas 4 generated by the decomposition of the solid electrolyte interface film. This eliminates the need for the gas 4 to move through the gap between the electrolyte 3 and the battery electrode 1 or the space within the battery casing. This shortens the diffusion path of the gas 4 and prevents the gas 4 from accumulating inside the battery and causing brown spots. Furthermore, during the process of active ions migrating from the electrolyte 3 to the electrode active material 21 for extraction / embedding, positioning the gas absorption layer 22 on one side of the electrode active material layer 21 does not hinder the movement of active ions at the interface between the electrolyte 3 and the electrode active material 21, allowing the active ions to migrate normally.

[0065] Therefore, the gas absorption layer 22 can effectively absorb the gas 4 through its porous structure and adsorption capacity, reduce the internal pressure of the battery, and thus alleviate or eliminate the problems of battery volume expansion, battery electrode 1 / diaphragm 2 misalignment and increased battery polarization.

[0066] In some embodiments, the porous material comprises at least one of a MOF material, activated carbon, alkali metal alcoholate, alumina, biochar, silicon carbide, activated calcium oxide, a bio-based material, and activated silica gel.

[0067] MOF material (metal organic framework material) is a crystalline porous material with a periodic network structure formed by self-assembly of metal ions or metal clusters and organic ligands. It has a high specific surface area, adjustable pore size and pore shape, and good chemical stability and thermal stability. MOF material can be used as the material of the gas absorption layer 22. Through its porous structure, it adsorbs the gas 4 generated inside the battery, thereby reducing problems such as battery volume expansion.

[0068] Activated carbon is a carbon material with a highly developed pore structure, a large specific surface area and excellent adsorption performance. It can be used as the material of the gas absorption layer 22 to adsorb the gas 4 generated inside the battery.

[0069] Alkali metal alcoholates have good adsorption properties and can be used as the material of the gas absorption layer 22 to absorb the gas 4 generated inside the battery.

[0070] Alumina is a material with a high melting point, high hardness, and good chemical stability. Alumina can form a porous structure and be used as the material of the gas absorption layer 22 to absorb the gas 4 generated inside the battery. It can also be used as a component of the material of the gas absorption layer 22.

[0071] Biochar is a porous carbon material produced by pyrolysis of biomass at high temperature. It has a rich pore structure and a large specific surface area. It is used as the material of the gas absorption layer 22 and can effectively absorb the gas 4 generated inside the battery.

[0072] Silicon carbide is a ceramic material with high hardness and high melting point. It can be formed into a porous structure through specific processes (such as sintering, etching, etc.). It can be used as the material of the gas absorption layer 22, effectively absorbing the gas 4 generated inside the battery, and can also improve the thermal stability and mechanical strength of the battery.

[0073] Active calcium oxide is a material with strong adsorption properties that can react with gases 4 such as water vapor and carbon dioxide. It can be used as the material of the gas absorption layer 22 to effectively absorb the gases 4 generated inside the battery, and can also be used as a component of the material of the gas absorption layer 22.

[0074] Bio-based materials refer to materials derived from biomass. They can be formed into a porous structure through specific processing methods and used as the material of the gas absorption layer 22 to adsorb the gas 4 generated inside the battery. They can also be used as a component of the material of the gas absorption layer and have the advantages of environmental protection and sustainability.

[0075] Active silica gel is a porous silicon dioxide material with excellent adsorption properties and chemical stability. It is used as the material of the gas absorption layer 22 to adsorb the gas 4 generated inside the battery. Through its porous structure, it adsorbs the gas 4 generated inside the battery, which can reduce the problem of battery volume expansion.

[0076] At least one of the above materials is used together with the insulating material in the gas absorption layer 22, which can effectively absorb the gas 4 and reduce the internal pressure of the battery, thereby alleviating or eliminating the problems of battery volume expansion, pole piece / diaphragm 2 misalignment and increased battery polarization.

[0077] In some embodiments, the MOF material includes a matrix and functional groups. The MOF matrix includes at least one of an iron group, a magnesium group, a manganese group, and an aluminum group. The functional groups include at least one of a sulfonate group, an amino group, a carboxylic acid group, a sulfide group, an amine group, a nitrogen group, a hydroxyl group, a thiol group, an aldehyde group, and a methyl group.

[0078] As can be understood, the MOF matrix is the main component of the MOF material skeleton. Among them, iron-based MOF has good thermal and chemical stability and is suitable for use in high-temperature or corrosive environments. Magnesium-based MOF has a lighter weight, which helps to reduce the overall weight of the battery. Manganese-based MOF has structural diversity and adjustability, as well as a large specific surface area and porosity, which can provide a large number of adsorption sites, which is conducive to the efficient adsorption of gas 4. Aluminum-based MOF has a higher specific surface area and porosity, which is conducive to the adsorption and storage of gas 4.

[0079] Functional groups are organic ligands attached to the MOF matrix, connecting to metal ions or metal clusters through coordination bonds to form MOF materials with specific structures and functions. Among them, acidic groups such as sulfonate groups and carboxylic acid groups can interact with the basic parts of gas 4 molecules, thereby enhancing the adsorption capacity of gas 4 molecules. Basic groups such as amino groups, amine groups, and nitrogen groups can undergo acid-base reactions with acidic gas 4 molecules (such as carbon dioxide), improving adsorption efficiency. Hydroxyl groups, thiol groups, aldehyde groups, etc. bind to gas 4 molecules through interactions such as hydrogen bonds and van der Waals forces, achieving effective adsorption of gas 4. Sulfur groups, methyl groups, etc. interact with gas 4 molecules through specific chemical reactions or physical adsorption mechanisms, achieving effective adsorption of gas 4.

[0080] By combining at least one of the above-mentioned MOF matrices and at least one of the functional groups as the material of the gas absorption layer 22, the gas 4 can be effectively absorbed to reduce the internal pressure of the battery, further reducing or eliminating the problems of battery volume expansion, battery pole piece 1 / diaphragm 2 misalignment and increased battery polarization.

[0081] In some embodiments, the MOF material includes at least one of Fe-MOF, MOF-5, ZIF-8, UiO-66, MIL-101, and HKUST-1.

[0082] Fe-MOF, or iron-based MOF, typically contains iron ions as the metal center, which form a porous structure with organic ligands through coordination bonds. It has good thermal and chemical stability and can serve as a gas absorption layer to effectively adsorb gases generated inside the battery4.

[0083] MOF-5, also known as IRMOF-1, is a MOF material composed of zinc ions and terephthalic acid ligands. It has a high specific surface area and a tunable pore structure, and has excellent gas 4 adsorption performance. Its porous structure can capture and fix gas 4 generated inside the battery, thereby extending the battery's service life and stability.

[0084] ZIF-8 (zeolite imidazolate framework material-8) is a MOF material composed of zinc ions and 2-methylimidazole ligands. It has excellent thermal and chemical stability, as well as high specific surface area and porosity. It is used as a gas absorption layer to effectively reduce the gas pressure inside the battery and improve the safety and performance of the battery.

[0085] UiO-66 is a MOF material formed by coordination bonds between zirconium ions and terephthalic acid ligands. It exhibits extremely high thermal and chemical stability, as well as excellent mechanical strength. The pore structure of UiO-66 can be regulated by varying the length of the ligands or introducing other functional groups. The stability and porosity of UiO-66 make it an excellent material for the gas absorption layer 22.

[0086] MIL-101 is a MOF material composed of chromium ions and terephthalic acid ligands. It has extremely high specific surface area and porosity, as well as good water stability and thermal stability. It can be used as a material for an efficient gas absorption layer 22 to reduce the accumulation of gas 4 inside the battery.

[0087] HKUST-1 is a MOF material composed of copper ions and trimesic acid ligands. It has good thermal and chemical stability, a unique pore structure, and can effectively adsorb gases generated by batteries4.

[0088] At least one of the above materials is used as the material of the gas absorption layer 22, which can improve the stability of the gas absorption layer 22 and have better gas 4 absorption performance at higher temperatures (for example, greater than 60°C) to reduce the internal pressure of the battery, and can further reduce or eliminate the problems of battery volume expansion, battery electrode 1 / diaphragm 2 misalignment and increased battery polarization.

[0089] In some embodiments, the insulating material includes a ceramic material.

[0090] It can be understood that ceramic materials have good insulation properties and good thermal stability, which can ensure the stability of the gas absorption layer 22.

[0091] The porous material and the insulating material are connected by coordination. In other words, the ceramic material and the porous material (such as MOF material) can form a stable connection through chemical coordination.

[0092] In some embodiments, the porous material and the insulating material are physically mixed, that is, the ceramic material and the porous material (such as MOF material) can be stably connected by physical mixing.

[0093] By means of the connection between the porous material and the insulating material, the battery electrode 1 can be made more stable during the cycle and storage process.

[0094] In some embodiments, the ratio of the mass of the porous material to the total mass of the material of the gas absorption layer 22 is in the range of 0.1 to 0.5.

[0095] For example, the ratio of the mass of the porous material to the total mass of the material of the gas absorption layer 22 may be 0.1, 0.2, 0.3, 0.4 or 0.5, etc., which is not limited here.

[0096] When the ratio of the mass of the porous material to the total mass of the material of the gas absorption layer 22 is small, for example, less than 0.1, the mass of the porous material accounts for a small proportion, and its surface area and porosity may not be sufficient to fully absorb the gas 4 generated inside the battery, causing the gas 4 to accumulate inside the battery and increase the internal pressure of the battery. Moreover, the porous material also plays a role in mitigating volume changes in the battery system. When the ratio of the mass of the porous material to the total mass of the material of the gas absorption layer 22 is small, it may not be able to effectively mitigate the volume changes of the battery during the charge and discharge process (such as the growth and dissolution of lithium dendrites in lithium-ion batteries), thereby affecting the overall stability of the system.

[0097] When the ratio of the mass of the porous material to the total mass of the material of the gas absorption layer 22 is large, for example greater than 0.5, the porous material provides more pores, and the gas 4 absorption effect may be better, but at the same time the insulation effect becomes worse, and the risk of bending, contact and short circuit of the positive and negative tabs increases.

[0098] Through the above-mentioned setting, the ratio range of the mass of the porous material to the total mass of the material of the gas absorption layer 22 is set within an appropriate range to ensure that the battery has no short-circuit risk, and to ensure that there is sufficient surface area and porosity to timely and effectively adsorb the gas 4 generated inside the battery, reduce the internal pressure of the battery, and further reduce or eliminate the problems of battery volume expansion, battery electrode 1 / diaphragm 2 misalignment and increased battery polarization.

[0099] In some embodiments, as Figure 5A and Figure 5B As shown, the battery electrode 1 includes: a first electrode 11 and a second electrode 12. The gas absorption layer 22 provided on one side of the first electrode 11 is a first sub-absorption layer 221. The gas absorption layer 22 provided on one side of the second electrode 12 is a second sub-absorption layer 222.

[0100] The dimension D1 of the first sub-absorption layer 221 along the first direction X is greater than or equal to the dimension D2 of the second sub-absorption layer 222 along the first direction X, that is, D1≥D2. The first direction X intersects with the thickness direction of the battery electrode.

[0101] In some examples, the first electrode 11 is a positive electrode, and the second electrode 12 is a negative electrode.

[0102] For example, the dimension D1 of the positive electrode sheet in the first direction X may be 5 mm, 6 mm, 7 mm, 8 mm or 9 mm, etc., which is not limited here.

[0103] For example, the dimension D2 of the negative electrode sheet in the first direction X may be 2.5 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm or 6 mm, etc., which is not limited here.

[0104] In some examples, in order to reduce the occurrence of lithium plating in the battery and prevent more lithium metal from breaking through the diaphragm 2 and affecting battery performance, the area of active material coated on the negative electrode plate should be larger than the area of active material coated on the positive electrode plate.

[0105] Therefore, the dimension D1 of the first sub-absorption layer 221 along the first direction X can be set to be greater than or equal to the dimension D2 of the second sub-absorption layer 222 along the first direction X. That is, the dimension D1 of the positive electrode plate in the first direction X is greater than or equal to the dimension D2 of the negative electrode plate in the first direction X. This makes the area of the gas absorption layer 22 of the positive electrode plate larger than the area of the gas absorption layer 22 of the negative electrode plate, thereby fully utilizing the space available for forming the gas absorption layer 22 on the positive electrode plate and improving the gas 4 adsorption effect of the positive electrode plate.

[0106] In some embodiments, as Figure 2 As shown, the gas absorption layer 22 disposed on the side of the electrode active material layer 21 close to the tab 30 is the third sub-absorption layer 223. The gas absorption layer 22 disposed on the side of the electrode active material layer 21 away from the tab 30 is the fourth sub-absorption layer 224.

[0107] A dimension D3 of the third sub-absorption layer 223 along the first direction X is greater than or equal to a dimension D4 of the fourth sub-absorption layer 224 along the first direction X, that is, D3 ≥ D4.

[0108] For example, the dimension D3 of the third sub-absorption layer 223 along the first direction X may be 4 mm, 5 mm, 6 mm, 7 mm, 8 mm or 9 mm, etc., which is not limited here.

[0109] For example, the dimension D4 of the fourth sub-absorption layer 224 along the first direction X may be 2.5 mm, 3.5 mm, 4.5 mm, 5 mm, 6 mm, or 7 mm, etc., which is not limited here.

[0110] Through the above arrangement, the gas absorption area of the third sub-absorption layer 223 can be made larger than the gas 4 absorption area of the fourth sub-absorption layer 224, which can prevent lithium deposition and make full use of the space on the battery electrode 1, expand the gas absorption area, and enhance the gas adsorption effect.

[0111] In some examples, such as Figure 3A and Figure 3B As shown, there is one gas absorption layer 22 , which is disposed on a side of the electrode active material layer 21 close to the tab 30 ; or, on a side of the electrode active material layer 21 away from the tab 30 , which is not limited here.

[0112] Exemplarily, the battery electrode 1 includes: Figure 3A The second pole piece 12 and Figure 3B In the first electrode sheet 11 shown, the gas absorption layer 22 is provided on a side of the electrode active material layer 21 of the first electrode close to the electrode tab 30 .

[0113] In some embodiments, there are multiple gas absorption layers 22 , and the gas absorption layers 22 are disposed on a side of the electrode active material layer 21 close to the tab 30 and a side of the electrode active material layer 21 away from the tab 30 .

[0114] In some examples, such as Figure 4A and Figure 4B As shown, the number of gas absorption layers 22 is three, and the gas absorption layer 22 is arranged on the side of the relative electrode active material layer 21 close to the pole tab 30; the gas absorption layer 22 is arranged on the side of the relative electrode active material layer 21 close to the pole tab 30 and the side of the relative electrode active material layer 21 away from the pole tab 30.

[0115] For example, Figure 4A For the negative electrode, Figure 4B It is the positive electrode.

[0116] In other examples, such as Figure 5A and Figure 5B As shown, the number of gas absorption layers 22 is four, one gas absorption layer 22 is arranged on the side of the relative electrode active material layer 21 close to the pole tab 30 and the other is arranged on the side of the relative electrode active material layer 21 away from the pole tab 30; one gas absorption layer 22 is arranged on the side of the relative electrode active material layer 21 close to the pole tab 30 and the other is arranged on the side of the relative electrode active material layer 21 away from the pole tab 30.

[0117] For example, Figure 5A For the negative electrode, Figure 5B It is the positive electrode.

[0118] That is to say, in the battery, the positive electrode plate and the negative electrode plate are composed of a battery plate 1 with at least one gas absorption layer 22 for absorbing gas 4, which can expand the area for absorbing gas 4 in the battery, is more conducive to the absorption of gas 4 in the battery, and can further reduce or eliminate the problems of battery volume expansion, plate / diaphragm 2 misalignment and increased battery polarization.

[0119] In some embodiments, as Figure 6As shown, the dimension H of the gas absorption layer 22 along the second direction Y ranges from 100 μm to 150 μm.

[0120] For example, the dimension H of the gas absorption layer 22 along the second direction Y may be 100 μm, 110 μm, 120 μm, 130 μm, 140 μm or 150 μm, etc., which is not limited here.

[0121] When the dimension H of the gas absorption layer 22 along the second direction Y is large, for example greater than 150 μm, the diffusion path of the gas 4 inside the material may become longer, thereby increasing the diffusion resistance of the gas 4 molecules in the material, resulting in a decrease in the absorption rate of the gas 4, making it impossible for the gas 4 to be absorbed in a timely and effective manner.

[0122] When the dimension H of the gas absorption layer 22 along the second direction Y is small, for example, less than 100 μm, the material of the gas absorption layer 22 may not be sufficient to fully absorb the gas 4 generated inside the battery, causing the gas 4 to accumulate inside the battery, increasing the internal pressure of the battery, and may not be able to effectively alleviate the volume change of the battery during the charging and discharging process, thereby affecting the overall stability of the system.

[0123] Through the above-mentioned setting, the size of the gas absorption layer 22 along the second direction Y is set within an appropriate range, so that the gas absorption layer 22 can more effectively absorb the gas 4 generated by the battery during the cycle and storage process, which helps to reduce the increase in the internal pressure of the battery, maintain the stability of the internal environment of the battery, and further reduce or eliminate the problems of battery volume expansion, battery electrode 1 / diaphragm 2 misalignment and increased battery polarization.

[0124] In a second aspect, some embodiments of the present application provide a method for preparing a battery electrode 1. Figure 7 As shown, the preparation method of the battery electrode 1 includes: S1 to S3.

[0125] S1: providing a current collector 10;

[0126] S2: forming a tab 30 on one side of the current collector 10 along the first direction X, and arranged on one side of the current collector 10 along the first direction X. The first direction X intersects with the thickness direction of the battery electrode 1;

[0127] S3: A material layer 20 is formed on at least one side of the current collector 10 along the second direction Y, and the material layer 20 includes an electrode active material layer 21 and at least one gas absorption layer 22. The electrode active material layer 21 is provided on at least one side of the current collector 10 along the second direction Y. At least one gas absorption layer 22 is provided on at least one side of the electrode active material layer 21 along the first direction X, and is provided on the same side of the current collector 10 as the electrode active material layer 21. The second direction Y is the thickness direction of the battery electrode 1. The material of the gas absorption layer 22 includes: a porous material and an insulating material. Here, the electrode active material layer 21 can be formed by mixing an active substance, a conductive agent and a binder, and coated on the surface of the current collector 10.

[0128] For example, the positive electrode active material may be lithium iron phosphate, lithium manganese iron phosphate, lithium-rich base, and the like.

[0129] For example, the negative electrode active material may be graphite, silicon, or the like.

[0130] For example, the introduction of the material of the gas absorption layer 22 can refer to the above content and will not be repeated here.

[0131] In some embodiments, S3 forming a material layer 20 on at least one side of the current collector along the second direction includes: forming at least one gas absorption layer 22 .

[0132] The forming of at least one gas absorption layer includes at least one of the following methods SA to SC.

[0133] SA: A porous material and an insulating material are mixed and applied to at least one side of the current collector 10 along the second direction Y to form a gas absorption layer 22. For example, the porous material and the insulating material in SA can be physically mixed. Here, the gas absorption layer 22 can be made by homogenizing a composite material of the porous material and the insulating material, a binder, and a solvent in a certain mass ratio, and then uniformly applying it to at least one side of the current collector 10 along the second direction Y.

[0134] For example, the porous material and the insulating material in the SA may be compounded by chemically coordinating the porous material and the insulating material.

[0135] SB: A porous material is coated on at least one side of the current collector 10 along the second direction Y, and an insulating material is coated on a side of the porous material away from the current collector 10 to form a gas absorption layer 22 .

[0136] For example, in SB, the porous material may be sprayed on at least one side of the current collector 10 along the second direction Y first and then the insulating material may be sprayed.

[0137] SC: an insulating material is coated on at least one side of the current collector 10 along the second direction Y, and a porous material is coated on a side of the insulating material away from the current collector 10 to form a gas absorption layer 22 .

[0138] For example, in the SC, the insulating material may be sprayed on at least one side of the current collector 10 along the second direction Y first and then the porous material.

[0139] The battery pole piece 1 and the separator 2 in any of the above embodiments of the present application are subjected to subsequent lamination, assembly, injection, formation, aging and other processes to finally be prepared into a soft-pack, cylindrical or square aluminum shell battery.

[0140] According to the above-mentioned method for preparing the battery electrode, the following embodiments are provided.

[0141] Example 1

[0142] The structure of the battery electrode 1 is as follows Figure 4A and Figure 4B As shown, the method for preparing the battery electrode 1 includes steps: R1 to R3.

[0143] R1: Provide a current collector 10. The current collector 10 on the positive electrode sheet is aluminum foil, and the current collector 10 on the negative electrode sheet is copper foil.

[0144] R2: Forming the tab 30.

[0145] R3: An electrode active material layer 21 is formed on one side of the positive electrode current collector 10 along the second direction Y. The material of the electrode active material layer 21 includes a lithium-rich manganese-based positive electrode material. An electrode active material layer 21 is formed on one side of the negative electrode current collector 10 along the second direction Y. The electrode active material layer 21 includes graphite.

[0146] The MOF material and ceramic material are mechanically mixed, wherein the ratio of the mass of the MOF material to the sum of the masses of the MOF material and the ceramic material is 0.1. The mixture of the MOF material and the ceramic material is then mixed evenly with a binder and a solvent, and coated on the side of the positive electrode sheet near the tab 30, the side of the negative electrode sheet near the tab 30, and the side of the positive electrode sheet away from the tab 30. The side near the positive electrode tab 30 has a dimension of 8±1 mm along the first direction X, the side near the negative electrode tab 30 has a dimension of 5±1 mm along the first direction X, and the side away from the positive electrode tab 30 has a dimension of 6±1 mm along the first direction X. After baking, drying, and rolling, a gas absorption layer 22 having a dimension of 150 μm along the second direction Y is obtained.

[0147] Example 2

[0148] The difference between the battery electrode 1 provided in Example 2 and that in Example 1 is that the ratio of the mass of the porous material to the total mass of the gas absorption layer 22 is 0.5.

[0149] Comparative Example 1

[0150] The difference between the battery electrode 1 provided in Comparative Example 1 and Example 1 is that an equal amount of insulating material is used to replace the porous material.

[0151] The battery electrode 1 in the above embodiment is assembled with the diaphragm 2 and the electrolyte 3 into a blade battery. The designed capacity of the battery is 152Ah. By testing the internal pressure of the lithium-rich manganese-based battery under full-charge storage conditions, that is, when the internal pressure in the battery is relatively small, it indicates that the gas 4 released by the battery is absorbed by the gas absorption layer 22. In this way, the gas 4 absorption effect of the battery can be explored.

[0152] Test method: The batteries obtained in the embodiment and the comparative example were subjected to capacity tests, with a charge and discharge rate of 0.33C, a cut-off current of 0.05C, a charge cut-off voltage of 4.3V, a discharge cut-off voltage of 2.5V, and the remaining state of charge (SOC) of the battery being adjusted to a fully charged state after 3 cycles of charge and discharge. The batteries were placed in a high-temperature environment of 60°C for different storage times, wherein the storage times were 7 days, 14 days, 28 days, 60 days, and 90 days, respectively. The internal pressure of the battery was tested using an internal pressure collector, and the internal pressure data was collected. The results are detailed in Table 1.

[0153] Table 1 Internal pressure at 60℃ and full charge for different storage times (unit: MPa)

[0154] Experimental groups 7 days 14 days 28 days 60 days 90 days Example 1 0.05 0.057 0.068 0.088 0.092 Example 2 0.03 0.04 0.047 0.071 0.082 Comparative Example 1 0.083 0.103 0.11 0.13 0.143

[0155] It can be seen from Table 1 that after the battery electrodes 1 of Examples 1 and 2 are applied to the battery, after 7 days, 14 days, 28 days, 60 days and 90 days of storage, the internal pressure of the battery is less than the internal pressure of the battery obtained by the battery electrode 1 of Comparative Example 1, indicating that the battery electrode 1 provided in the present application has a significant absorption effect on the gas 4, which is related to the provision of a gas absorption layer 22 formed of a porous material and an insulating material on the battery electrode 1.

[0156] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A battery electrode, characterized in that: include: current collector; a tab, provided on one side of the current collector along the first direction; The first direction intersects with the thickness direction of the battery electrode; as well as, a material layer, the material layer comprising an electrode active material layer and at least one gas absorption layer; the electrode active material layer is disposed on at least one side of the current collector along the second direction; the at least one gas absorption layer is disposed on at least one side of the electrode active material layer along the first direction and is disposed on the same side of the current collector as the electrode active material layer; The second direction is the thickness direction of the battery electrode; Wherein, the material of the gas absorption layer includes: porous material and insulating material.

2. The battery electrode according to claim 1, characterized in that: The porous material includes at least one of MOF material, activated carbon, alkali metal alcoholate, alumina, biochar, silicon carbide, activated calcium oxide, bio-based material and activated silica gel.

3. The battery electrode according to claim 2, characterized in that: The MOF material includes: a matrix and a functional group; The matrix comprises at least one of an iron-based, a magnesium-based, a manganese-based and an aluminum-based matrix; The functional group includes at least one of a sulfonate group, an amino group, a carboxylic acid group, a sulfenyl group, an amine group, a nitrogen group, a hydroxyl group, a thiol group, an aldehyde group and a methyl group.

4. The battery electrode according to claim 3, characterized in that: The MOF material includes at least one of Fe-MOF, MOF-5, ZIF-8, UiO-66, MIL-101 and HKUST-1.

5. The battery electrode according to claim 1, characterized in that: The insulating material includes: ceramic material.

6. The battery electrode according to claim 1, characterized in that: The porous material and the insulating material are coordinately connected; and / or the porous material and the insulating material are physically mixed.

7. The battery electrode according to claim 1, characterized in that: The ratio of the mass of the porous material to the sum of the masses of the porous material and the insulating material is in a range of 0.1 to 0.

5.

8. The battery electrode according to claim 1, characterized in that: There are multiple gas absorption layers, and the gas absorption layers are arranged on a side of the electrode active material layer close to the electrode tab and a side of the electrode active material layer away from the electrode tab.

9. The battery pole piece according to claim 8, characterized in that: The battery electrode comprises: a first electrode and a second electrode; the gas absorption layer provided on one side of the first electrode is a first sub-absorption layer; the gas absorption layer provided on one side of the second electrode is a second sub-absorption layer; A dimension of the first sub-absorption layer along the first direction is greater than or equal to a dimension of the second sub-absorption layer along the first direction.

10. The battery electrode according to claim 8, characterized in that: The gas absorption layer provided on the side of the electrode active material layer close to the electrode tab is a third sub-absorption layer, and the gas absorption layer provided on the side of the electrode active material layer away from the electrode tab is a fourth sub-absorption layer; A dimension of the third sub-absorption layer along the first direction is greater than or equal to a dimension of the fourth sub-absorption layer along the first direction.

11. The battery electrode according to any one of claims 1 to 10, characterized in that: The size of the gas absorption layer along the second direction ranges from 100 μm to 150 μm.

12. A method for preparing a battery electrode, characterized in that: include: providing a current collector; forming a tab on one side of the current collector along a first direction, wherein the first direction intersects with a thickness direction of the battery electrode; as well as, forming a material layer on at least one side of the current collector along the second direction, the material layer comprising an electrode active material layer and at least one gas absorption layer; the electrode active material layer is disposed on at least one side of the current collector along the second direction; the at least one gas absorption layer is disposed on at least one side of the electrode active material layer along the first direction, and is disposed on the same side of the current collector as the electrode active material layer; The second direction is the thickness direction of the battery electrode; wherein the material of the gas absorption layer includes: porous material and insulating material.

13. The method for preparing a battery electrode according to claim 12, characterized in that: The forming of the material layer on at least one side of the current collector along the second direction comprises: forming at least one gas absorption layer; Wherein, forming at least one gas absorption layer includes at least one of the following methods: Mixing the porous material and the insulating material, and coating the mixture on at least one side of the current collector along the second direction to form the gas absorption layer; Applying the porous material to at least one side of the current collector along the second direction, and applying the insulating material to a side of the porous material away from the current collector to form the gas absorption layer; The insulating material is coated on at least one side of the current collector along the second direction, and the porous material is coated on a side of the insulating material away from the current collector to form the gas absorption layer.

14. A battery, characterized in that: include: A separator and a battery pole piece according to any one of claims 1 to 11.

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