Positive pole piece of lithium battery, battery cell, battery monomer, battery pack, electric vehicle and electric equipment
By covering the main layer of the high-nickel ternary lithium-ion battery with a sandwich structure with thermally stable material outside the main layer of the high-nickel ternary material, the problem of poor short-circuit tolerance in the lithium-ion battery is solved, and higher safety and suitable for mass production are achieved. plan.
Patent Information
- Application Number
- CN202420215830.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-26
- Publication Date
- 2025-01-07
- Estimated Expiration
- 2034-01-26
AI Technical Summary
The internal short-circuit tolerance of high-nickel ternary material lithium-ion batteries has poor internal short-circuit resistance and has safety problems.
A sandwich structure designed with a thermally stable material, including the first and second safety layers of materials such as lithium iron phosphate and lithium manganese phosphate, which are coated on the main layer of high nickel ternary material to form a sandwich structure to suppress internal short circuits. .
It effectively improves the ability to withstand the internal short circuit of the battery, prevents the main material layer from getting out of control, and has low preparation requirements and low cost, making it suitable for mass production.
Smart Images
Figure CN222320281U_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the field of new energy technology, and specifically relates to a positive electrode sheet, a battery cell, a battery cell, a battery pack, an electric vehicle and an electrical device of a lithium battery. Background Art
[0002] High-nickel ternary material is a positive electrode material with nickel, cobalt and manganese as the three elements as the main components. It is usually used in lithium-ion batteries and is the current focus of power battery research.
[0003] Because high-nickel ternary materials have a higher nickel content, their energy density is higher than other materials; the charging and discharging performance of high-nickel ternary materials is also relatively outstanding, and can be widely used in electric vehicles, electric bicycles and other fields; high-nickel ternary materials have a long cycle life and can meet the needs of long-term use.
[0004] Because of the above advantages, high nickel ternary materials are currently being widely promoted and applied. However, lithium-ion batteries made of high nickel ternary materials also have certain safety issues. At present, the main problem of lithium-ion batteries made of high nickel ternary materials is the safety problem of poor internal short circuit tolerance of the battery. Utility Model Content
[0005] The purpose of the present application is to provide a positive electrode plate, a battery cell, a battery cell, a battery pack, an electric vehicle and an electrical device of a lithium battery to solve the problem of poor internal short circuit tolerance of the battery.
[0006] According to a first aspect of an embodiment of the present application, a positive electrode plate of a lithium battery is provided, and the positive electrode plate may include: a foil material and a laminated main material coated on the upper and lower surfaces of the foil material;
[0007] The laminated main material is a main material layer wrapped by a thermally stable material.
[0008] In some optional embodiments of the present application, the laminated main material includes a first safety layer, a main material layer and a second safety layer which are stacked in sequence.
[0009] In some optional embodiments of the present application, the material of the first safety layer includes: one or more combinations of lithium iron phosphate, lithium iron manganese phosphate and nickel-cobalt-manganese ternary materials;
[0010] The material of the second safety layer includes: one or more combinations of lithium iron phosphate, lithium iron manganese phosphate and nickel-cobalt-manganese ternary materials.
[0011] In some optional embodiments of the present application, the thickness of the first security layer is: 1 μm to 30 μm;
[0012] The thickness of the second safety layer is 1 μm to 30 μm.
[0013] In some optional embodiments of the present application, the material of the main material layer includes: high-nickel ternary material.
[0014] According to a second aspect of the embodiments of the present application, a battery cell is provided, which may include: a positive electrode plate of a lithium battery as described in any one of the embodiments of the first aspect.
[0015] According to a third aspect of the embodiments of the present application, a battery cell is provided, which may include: the positive electrode plate of the lithium battery described in any one of the embodiments of the first aspect or the battery cell described in any one of the embodiments of the second aspect.
[0016] According to a fourth aspect of the embodiments of the present application, a battery pack is provided, which may include: a plurality of battery cells described in the embodiments of the second aspect or a plurality of battery cells described in the embodiments of the third aspect.
[0017] According to a fifth aspect of the embodiments of the present application, an electric vehicle is provided, which may include: the battery cell described in the embodiment of the third aspect or the battery pack described in the embodiment of the fourth aspect.
[0018] According to a sixth aspect of the embodiments of the present application, an electrical device is provided, which may include: the battery cell described in the fourth aspect of the embodiments or the battery pack described in the fifth aspect of the embodiments.
[0019] The above technical solution of the present application has the following beneficial technical effects:
[0020] The positive electrode sheet of the embodiment of the present application is coated with a thermally stable material outside the positive electrode main material layer to form a safe sandwich structure. In this way, when a battery made of the positive electrode sheet has an internal short circuit in the battery cell, the sandwich structure can effectively suppress the internal short circuit problem, thereby preventing the main material layer from having thermal runaway, thereby greatly improving the battery's internal short circuit tolerance. In addition, the structure has low preparation requirements, low cost, and is suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 is a schematic diagram of the positive electrode structure of a lithium battery in an exemplary embodiment of the present application;
[0022] Figure 2 It is a schematic diagram of the positive electrode structure of a lithium battery in a specific embodiment of the present application. Description of the drawings:
[0024] 100: foil; 200: laminated main material; 210: first safety layer; 220: main material layer; 230: second safety layer. DETAILED DESCRIPTION
[0025] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with specific implementations and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concepts of the present application.
[0026] The accompanying drawings show schematic diagrams of layer structures according to embodiments of the present application. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clarity. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.
[0027] Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.
[0028] In the description of the present application, it should be noted that the terms "first", "second" and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.
[0029] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.
[0030] In conjunction with the accompanying drawings, the positive electrode sheet, battery cell, battery cell, battery pack, electric vehicle and electrical equipment of the lithium battery provided in the embodiments of the present application are described in detail through specific embodiments and their application scenarios.
[0031] like Figure 1 As shown, in a first aspect of an embodiment of the present application, a positive electrode sheet of a lithium battery is provided, and the positive electrode sheet may include: a foil material 100 and a laminated main material 200 coated on the upper and lower surfaces of the foil material 100;
[0032] The laminated main material 200 is a main material layer 220 wrapped by a thermally stable material.
[0033] The positive electrode sheet of this embodiment forms a safe sandwich structure by coating the positive electrode main material layer 220 with a thermally stable material. In this way, when a battery made of the positive electrode sheet has an internal short circuit in the battery cell, the sandwich structure can effectively suppress the internal short circuit problem, thereby preventing the main material layer 220 from having thermal runaway, thereby greatly improving the battery's internal short circuit tolerance. In addition, the structure has low preparation requirements, low cost, and is suitable for mass production. Exemplarily, the material of the foil 100 in this embodiment can be aluminum. The foil can be a conventional aluminum foil or a composite current collector.
[0034] In some embodiments, the laminated main material 200 includes a first safety layer 210 , a main material layer 220 , and a second safety layer 230 which are stacked in sequence.
[0035] In this embodiment, the first safety layer 210 and the second safety layer 230 sandwich the main material layer 220, and when an internal short circuit occurs in the battery cell, the internal short circuit problem can be effectively suppressed, thereby preventing the main material layer 220 from experiencing thermal runaway, thereby greatly improving the battery's internal short circuit tolerance. In this embodiment, the material of the foil 100 can be aluminum.
[0036] The first safety layer 210 and the second safety layer 230 are both made of materials with excellent thermal stability. The two can be made of the same material, or different materials can be selected according to the formula and system.
[0037] In some embodiments, the material of the first safety layer 210 includes: lithium iron phosphate and / or lithium iron manganese phosphate;
[0038] The material of the second safety layer 230 includes: lithium iron phosphate and / or lithium iron manganese phosphate.
[0039] In this embodiment, lithium iron phosphate and lithium iron manganese phosphate are positive electrode materials with good thermal stability, because these two materials have highly stable crystal structures, which also makes their safety performance excellent. However, these materials cannot replace the main material due to low capacity, low temperature difference, etc., but they are very excellent as safety coatings. In addition, the selection of these materials can reduce the thickness of the safety layer, weaken the impact on battery performance, and greatly improve the safety of the battery.
[0040] It should also be noted that some existing conceptual designs of safety coatings use materials with relatively high costs, have a significant impact on battery energy density, and will increase internal resistance and deteriorate the battery's electrical performance. Therefore, these conceptual safety coatings generally only remain in the laboratory stage and are difficult to apply to actual products.
[0041] In some embodiments, the first safety layer and the second safety layer may be composed of a low-capacity main material, a binder, and a conductive agent. Low-capacity main materials include but are not limited to lithium iron phosphate, lithium iron manganese phosphate, NCM111, NCM523, NCM622 materials, etc. These materials have excellent safety performance due to their own highly stable crystal structure, but these materials cannot replace the main materials due to low capacity, low temperature difference, etc., and are only feasible as safety coatings; adhesives include but are not limited to one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyacrylic acid and styrene-butadiene copolymer rubber (SBR); conductive agents include but are not limited to one or more of acetylene black, carbon black, graphite, graphene, graphene-like, carbon nanotubes, lithium lanthanum titanium oxide (LLTO), lithium zirconium oxide (LLZO), lithium aluminum titanium phosphate (LATP), etc., among which acetylene black, carbon black, graphite, graphene, graphene-like, and carbon nanotubes are electronic conductors, and lithium lanthanum titanium oxide (LLTO), lithium zirconium oxide (LLZO), and lithium aluminum titanium phosphate (LATP) are fast ion conductors. Any type can be used or used in a specific proportion as needed.
[0042] The thickness of the first safety layer and the second safety layer should be 1μm to 30μm, the mass fraction of the low-capacity main material should be 50% to 99%, the mass fraction of the binder should be 0.5% to 10%, and the mass fraction of the conductive agent should be 0.001% to 50%. If the mass fraction of the main material is too low, it will affect the energy density and thermal stability, and if it is too high, it will lead to a decrease in the bonding force of the electrode and an increase in internal resistance; if the mass fraction of the binder is too low, it will cause powder to fall off, and if it is too high, it will increase the internal resistance; if the mass fraction of the conductive agent is too low, it will affect the electrical performance, and if it is too high, it will lead to a decrease in thermal stability.
[0043] In this embodiment, the specific thickness of the first safety layer 210 and the second safety layer 230 can be determined according to the equipment capacity and the size of the selected main material layer, and the two can be the same or different.
[0044] In some embodiments, the main material layer may be composed of a high-capacity main material, a binder, a dispersant, and a conductive agent.
[0045] High-capacity main materials include but are not limited to NCM7 series, NCM8 series, NCM9 series, lithium-rich manganese-based materials, etc. This type of material has a high specific capacity and can improve energy density, but due to its own crystal structure, it has poor thermal stability and poor safety performance.
[0046] The main material layer, the first safety layer, and the second safety layer do not necessarily use the same solvent system and formula, and can use independent formulas. For example, the first safety layer, the second safety layer, and the main material layer can choose one water-based and one oil-based; the binder can use PVDF and SBR; different proportions of conductive agents can be added to different layers according to different conductivity requirements.
[0047] The first safety layer and the second safety layer can also use different formulas according to the different requirements of contacting the electrolyte and contacting the foil. For example, the second safety layer close to the foil tends to be electronically conductive, and the first safety layer close to the electrolyte tends to be ionically conductive, so different conductive agent formulas are used.
[0048] In some embodiments, the material of the main material layer 220 includes: high-nickel ternary material.
[0049] In this embodiment, the high-nickel ternary material has the advantages of high energy density, high cycle life, high charge and discharge efficiency, etc., and is suitable for vigorous promotion. However, this type of material has poor thermal stability and poor safety performance due to its own crystal structure, which requires the protection of the first safety layer 210 and the second safety layer 230. Exemplarily, the high-nickel ternary material can be nickel-cobalt-aluminum, nickel-cobalt-boron, etc.
[0050] like Figure 2 As shown, in a specific embodiment, a positive electrode plate of a lithium battery is provided, and the positive electrode plate may include: a foil material 100 and a laminated main material 200 coated on the upper and lower surfaces of the foil material 100;
[0051] The laminated main material 200 includes a first safety layer 210 , a main material layer 220 , and a second safety layer 230 which are sequentially laminated.
[0052] The main material layer 220 is a high-capacity and low-security material, and the first security layer 210 and the second security layer 230 are low-capacity and high-security materials.
[0053] This embodiment utilizes a sandwich structure to protect the high-capacity, low-safety main material layer 220 between the low-capacity, high-safety first safety layer 210 and the second safety layer 230. During the puncture test, the first safety layer 210 and the second safety layer 230 can withstand the high heat caused by the short circuit and protect the electrode material of the middle main material layer 220.
[0054] It should be noted that the main short-circuit points during needle puncture are at the interface between the main material layer 220 and the foil material 100 and the surface of the main material layer 220. In this embodiment, low-capacity and high-safety materials are coated on these two interfaces to protect the internal main material layer 220 from the short-circuit high temperature. At the same time, the high-gram capacity of the main material layer 220 is not affected, which solves the safety problem in the application of high-gram capacity main materials. In addition, the structure has low preparation requirements, low cost, and is suitable for mass production.
[0055] In addition, this embodiment also provides a preparation process of the structure, which may include:
[0056] First, a second security layer 230 is thinly applied on the foil 100 using gravure coating;
[0057] Then, the main material layer 220 is coated according to the designed surface density by transfer coating or extrusion coating;
[0058] Finally, the second security layer 230 is thinly coated on the main material layer 220 by gravure coating.
[0059] Thus, a sandwich coating structure is formed, protecting the high-capacity and low-security main material layer 220 between the low-capacity and high-security first security layer 210 and the second security layer 230 .
[0060] In a second aspect of the embodiments of the present application, a battery cell is provided, which may include: a positive electrode plate of a lithium battery as described in any one of the embodiments of the first aspect.
[0061] For the convenience and simplicity of description, the specific structure of the battery cell described above can refer to the corresponding introduction in the aforementioned lithium battery positive electrode plate embodiment. The technical problems solved and the technical effects achieved by the positive electrode plate of the lithium battery can also be achieved by the battery cell, which will not be repeated here.
[0062] In a third aspect of the embodiments of the present application, a battery cell is provided. The battery cell may include: the positive electrode plate of the lithium battery described in any one of the embodiments of the first aspect or the battery cell described in any one of the embodiments of the second aspect.
[0063] For the convenience and simplicity of description, the specific structure of the battery cell described above can refer to the corresponding introduction in the aforementioned lithium battery positive electrode plate or battery cell embodiment. The technical problems solved and the technical effects achieved by the positive electrode plate or battery cell of the lithium battery can also be achieved by the battery cell and will not be repeated here.
[0064] In a fourth aspect of the embodiments of the present application, a battery pack is provided, which may include: a plurality of battery cells described in the embodiments of the second aspect or a plurality of battery cells described in the embodiments of the third aspect.
[0065] For the convenience and simplicity of description, the specific structure of the battery pack described above can refer to the corresponding introduction in the aforementioned battery cell or battery single body embodiments. The technical problems solved and the technical effects achieved by the battery cells or battery single bodies can also be achieved by the battery pack and will not be repeated here.
[0066] In a fifth aspect of the embodiments of the present application, an electric vehicle is provided, which may include: the battery cell described in the third aspect of the embodiments or the battery pack described in the fourth aspect of the embodiments.
[0067] For the convenience and simplicity of description, the specific structure of the electric vehicle described above can refer to the corresponding introduction in the aforementioned battery pack embodiment. The technical problems solved and the technical effects achieved by the battery pack can also be achieved by the electric vehicle and will not be repeated here.
[0068] In a sixth aspect of the embodiments of the present application, an electrical device is provided, which may include: the battery cell described in the fourth aspect of the embodiments or the battery pack described in the fifth aspect of the embodiments.
[0069] For the convenience and simplicity of description, the specific structure of the electrical equipment described above can refer to the corresponding introduction in the aforementioned battery pack embodiment. The technical problems solved and the technical effects achieved by the battery pack can also be achieved by the electrical equipment, and will not be repeated here.
[0070] In summary, the present application aims to provide a positive electrode plate for a lithium battery, the positive electrode plate for the lithium battery comprising: a foil material and a laminated main material coated on the upper and lower surfaces of the foil material; the laminated main material is a main material layer wrapped by a thermally stable material. The positive electrode plate forms a safe sandwich structure by coating the thermally stable material outside the positive electrode main material layer, so that when a battery made using the positive electrode plate has an internal short circuit in the battery cell, the sandwich structure can effectively suppress the internal short circuit problem, thereby preventing the main material layer from having thermal runaway, and thus greatly improving the battery's internal short circuit tolerance. In addition, the structure has low preparation requirements, low cost, and is suitable for mass production.
[0071] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.
Claims
1. A positive electrode plate of a lithium battery, characterized in that: include: A foil material (100) and a laminated main material (200) coated on the upper and lower surfaces of the foil material (100); The laminated main material (200) is a main material layer (220) wrapped by a thermally stable material; The laminated main material (200) comprises a first safety layer (210), a main material layer (220) and a second safety layer (230) which are stacked in sequence.
2. The positive electrode plate of a lithium battery according to claim 1, characterized in that: The thickness of the first safety layer (210) is 1 μm to 30 μm; The thickness of the second safety layer (230) is 1 μm to 30 μm.
3. A battery cell, characterized in that: include: The positive electrode sheet of the lithium battery according to claim 1 or 2.
4. A battery cell, characterized in that: include: The positive electrode sheet of the lithium battery according to claim 1 or 2 or the battery cell according to claim 3.
5. A battery pack, characterized in that: include: A plurality of battery cells as claimed in claim 3 or a plurality of battery cells as claimed in claim 4.
6. An electric vehicle, characterized in that: include: The battery cell according to claim 4 or the battery pack according to claim 5.
7. An electrical equipment, characterized in that: include: The battery cell according to claim 4 or the battery pack according to claim 5.