Battery monomer, battery device and power utilization device

Abstract

The invention relates to a battery monomer, a battery device and a power utilization device, the battery monomer comprises a positive pole piece, a negative pole piece and a separator, the positive pole piece comprises a positive current collector and a positive material layer arranged on at least one surface of the positive current collector; the positive electrode material layer comprises a positive electrode lithium supplement agent and metal oxide particles; the metal oxide comprises at least one of CeO2, TiO2, Cu2O, CuO, WO3, NiO, Fe2O3, Co3O4, MnO, ZnO, MnO2 and MoO3, and the metal oxide comprises at least one of CeO2, TiO2, Cu2O, CuO, WO3, NiO, Fe2O3, Co3O4, MnO, ZnO, the mass ratio of the anode lithium supplement agent to the metal oxide particles is 100: (0.1-20). According to the battery monomer, the positive electrode lithium supplement agent and the metal oxide particles are applied at the same time, so that the negative effect caused by active oxygen is reduced while the lithium supplement effect is achieved, and the capacity exertion and cycle performance of the battery can be improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a battery cell, a battery device, and an electrical device. Background Technology

[0002] Rechargeable batteries, represented by lithium-ion batteries, have been continuously developed and have been widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power plants, as well as in many fields such as power tools, electric bicycles, electric motorcycles, electric cars, military equipment, and aerospace.

[0003] During the initial charge and discharge of a battery, a solid electrolyte interphase (SEI) film forms on the surface of the negative electrode. This SEI film formation consumes a significant amount of active lithium ions, leading to a loss of recyclable lithium. Pre-replenishing the positive or negative electrode with lithium is an effective method to address this. However, when using lithium replenishing agents at the positive electrode, reactive oxygen species are easily generated, resulting in gas production and heat release. Summary of the Invention

[0004] The purpose of this application is to provide a battery cell, a battery device, and an electrical device. The battery cell, by simultaneously applying a positive electrode lithium supplement and metal oxide particles, not only plays a role in lithium supplementation but also reduces the negative effects of reactive oxygen species, which is beneficial to improving the battery's capacity utilization and cycle performance.

[0005] To this end, this application provides a battery cell, including a positive electrode, a negative electrode, and a separator. The positive electrode includes a positive current collector and a positive electrode material layer disposed on at least one surface of the positive current collector. The positive electrode material layer includes a positive electrode lithium supplement and metal oxide particles. The metal oxide includes at least one of CeO2, TiO2, Cu2O, CuO, WO3, NiO, Fe2O3, Co3O4, MnO, ZnO, MnO2, and MoO3. The mass ratio of the positive electrode lithium supplement to the metal oxide particles is 100:(0.1-20).

[0006] By applying a positive electrode lithium supplement, excess lithium salt can be provided during the first charge of the battery to compensate for the lithium consumption during SEI film formation, thereby increasing the battery's specific capacity. Using metal oxide particles as additives in the positive electrode material layer allows the metal oxides to react with superoxide radicals generated by the positive electrode lithium supplement, rapidly converting them into oxygen. This prevents oxygen radicals from decomposing the electrolyte, thus reducing gas and heat generation problems caused by reactive oxygen species. When the mass percentage of metal oxides is within the aforementioned range, it reduces the generation of oxygen radicals without deteriorating the positive and negative electrode interfaces, thereby improving the capacity utilization and safety performance of the lithium-ion battery.

[0007] In some embodiments, the mass ratio of the positive electrode lithium supplement to the metal oxide particles is 100:(0.1 to 10).

[0008] By further adjusting the mass ratio of positive electrode lithium supplement to metal oxide particles to 100:(0.1~10), it is beneficial to improve the battery capacity.

[0009] In some embodiments, the particle size Dv50 of the metal oxide particles is 5 to 50 nm.

[0010] In the embodiments of this application, using smaller metal oxide particle sizes, such as 5-50 nm, is beneficial to enhance the reaction between metal oxides and active oxygen, better consume active oxygen, and avoid adverse effects such as decomposition of electrolyte by oxygen free radicals.

[0011] In some embodiments, the particle size Dv50 of the metal oxide particles is 5 to 15 nm.

[0012] By applying the aforementioned particle size of metal oxide particles, their reactivity with active oxygen is further improved, which is beneficial in reducing gas generation and heat generation problems during battery use.

[0013] In some embodiments, the positive electrode lithium replenishing agent includes at least one of the following: Li6CoO4, Li5FeO4, Li3VO4, Li2MoO3, Li2RuO3, Li2MnO3, Li2MnO2, Li2NiO2, Li2CuO2, Li2Cu x Ni 1-x M y O2, where 0 < x < 1, 0 ≤ y < 0.1, and M is selected from one or more of Zn, Sn, Mg, Fe and Mn.

[0014] By using the above-mentioned positive electrode lithium replenisher, its chemical properties in generating active oxygen are more suitable for matching the metal oxide particles in the embodiments of this application, so that the generated active oxygen can be almost completely consumed by the metal oxide, which is beneficial to improving the battery's capacity and safety performance.

[0015] In some embodiments, the particle size Dv50 of the positive electrode lithium replenishing agent is 1–20 μm.

[0016] In some embodiments, the positive electrode material layer further includes a positive electrode active material, wherein the particle size Dv50 of the positive electrode active material is 0.1 to 20 μm.

[0017] By selecting more suitable particle sizes for the positive electrode lithium replenisher and / or the positive electrode active material, it is beneficial to obtain better battery capacity improvement.

[0018] In some embodiments, the ratio of the particle size Dv50 of the positive electrode lithium replenisher to the particle size Dv50 of the positive electrode active material is A, where 1 ≤ A ≤ 12.

[0019] The ratio of the positive electrode lithium supplement Dv50 to the positive electrode active material Dv50 affects the lithium-ion conduction capability of the positive electrode. As the ratio A decreases, the ion conduction capability of the positive electrode increases, but this also increases the contact area between the lithium supplement and the electrolyte, potentially leading to more side reactions. When the ratio A is controlled within the range of 1 to 12, a better balance between the ion conduction capability and side reactions of the positive electrode can be achieved, resulting in a superior overall performance.

[0020] In some embodiments, the mass percentage of the positive electrode lithium supplement in the positive electrode material layer is W1, where 0.1% ≤ W1 ≤ 10%.

[0021] When the mass ratio of the positive electrode lithium replenishing agent is within the above range, it is beneficial for the generated oxygen free radicals to be better consumed by the metal oxide, and it can also have excellent lithium replenishing effect.

[0022] A second aspect of this application provides a battery device comprising the battery cell described in the first aspect of this application.

[0023] A third aspect of this application provides an electrical device comprising a single battery cell as described in the first aspect of this application, or a battery device as described in the second aspect of this application.

[0024] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application, it can be implemented according to the contents of the specification. In order to make the above and other objects, features and advantages of this application more obvious and understandable, the specific implementation methods of this application are listed below. Attached Figure Description

[0025] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. In the drawings:

[0026] Figure 1 This is a schematic diagram of a battery cell according to one embodiment of this application;

[0027] Figure 2 yes Figure 1 An exploded view of a battery cell according to one embodiment of this application is shown.

[0028] Figure 3 This is a schematic diagram of a battery module according to one embodiment of this application;

[0029] Figure 4This is a schematic diagram of a battery pack according to one embodiment of this application;

[0030] Figure 5 yes Figure 4 An exploded view of a battery pack according to one embodiment of this application is shown;

[0031] Figure 6 This is a schematic diagram of an electrical device in which a single battery cell is used as a power source according to one embodiment of this application;

[0032] Explanation of reference numerals in the attached figures:

[0033] 1 Battery pack; 2 Upper housing; 3 Lower housing; 4 Battery module; 5 Battery cell; 51 Casing; 52 Electrode assembly; 53 End cap. Detailed Implementation

[0034] Exemplary embodiments of this disclosure will now be described in more detail. It should be understood that this disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0035] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60–120 and 80–110 are listed for a specific parameter, it is expected that ranges of 60–110 and 80–120 are also included. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are listed, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0036] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0037] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0038] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0039] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0040] During the initial charge and discharge of a battery, a solid electrolyte interphase (SEI) film forms on the surface of the negative electrode. This SEI film formation consumes a significant amount of active lithium ions, leading to a loss of recyclable lithium. Pre-replenishing the positive or negative electrode with lithium is an effective method to address this. However, when using lithium replenishing agents at the positive electrode, reactive oxygen species are easily generated, resulting in gas production and heat release.

[0041] This application utilizes a metal oxide with a certain mass ratio in the cathode material layer containing lithium replenishment to eliminate active oxygen, improve the problems of gas generation and heat generation in the battery, thereby enhancing battery capacity and improving safety performance.

[0042] The solutions described in the embodiments of this application are applicable to battery cells, battery devices using the battery cells, and electrical devices that use at least one of the battery cells and battery devices.

[0043] battery cell

[0044] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0045] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc. In some embodiments, the battery cell is a lithium-ion battery.

[0046] [Electrode Assembly]

[0047] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator positioned between the positive and negative electrodes. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0048] [Positive electrode plate]

[0049] In some embodiments, a battery cell is provided, including a positive electrode, a negative electrode, and a separator. The positive electrode includes a positive current collector and a positive electrode material layer disposed on at least one surface of the positive current collector. The positive electrode material layer includes a positive electrode lithium supplement and metal oxide particles. The metal oxide includes at least one of CeO2, TiO2, Cu2O, CuO, WO3, NiO, Fe2O3, Co3O4, MnO, ZnO, MnO2, and MoO3. The mass ratio of the positive electrode lithium supplement to the metal oxide particles is 100:(0.1-20).

[0050] By applying a positive electrode lithium replenisher, excess lithium salt can be provided during the first charge of the battery to compensate for the lithium consumption during SEI film formation, thereby increasing the battery's specific capacity. During the first charge (delithiation), the positive electrode lithium replenisher undergoes a structural change, generating superoxide radicals. These superoxide radicals are highly reactive and can cause electrolyte decomposition, easily releasing large amounts of heat and gas, and potentially leading to thermal runaway, resulting in battery combustion or explosion. In this embodiment, metal oxide particles are used as additives in the positive electrode material layer. The metal oxides can react with the superoxide radicals generated by the positive electrode lithium replenisher, rapidly converting them into oxygen, thus preventing oxygen radicals from decomposing the electrolyte. When the mass percentage of the metal oxide is within the aforementioned range, the generation of oxygen radicals is reduced without deteriorating the positive and negative electrode interfaces, thereby improving the capacity utilization and safety performance of the lithium-ion battery.

[0051] In some embodiments, the mass ratio of the positive electrode lithium replenishing agent to the metal oxide particles is 100:(0.1-10).

[0052] By further adjusting the mass ratio of positive electrode lithium supplement to metal oxide particles to 100:(0.1~10), it is beneficial to improve the battery capacity.

[0053] In some embodiments, the mass ratio of the positive electrode lithium supplement to the metal oxide particles can be selected from approximately 100:0.01, 100:0.05, 100:0.1, 100:0.2, 100:0.5, 100:1, 100:2, 100:3, 100:4, 100:5, 100:6, 100:7, 100:8, 100:9, 100:10, 100:11, 100:12, 100:13, 100:14, 100:15, 100:16, 100:17, 100:18, 100:19, 100:20, etc.

[0054] In some embodiments, the particle size Dv50 of the metal oxide particles is 5 to 50 nm; for example, it can be selected from about 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc.

[0055] In the embodiments of this application, using smaller metal oxide particle sizes, such as 5-50 nm, is beneficial to enhance the reaction between metal oxides and active oxygen, better consume active oxygen, and avoid adverse effects such as decomposition of electrolyte by oxygen free radicals.

[0056] Particle size Dv50, also known as median diameter or median particle size, refers to the particle size at which the cumulative particle size distribution percentage of a sample reaches 50% by volume; physically, it means that particles larger than Dv50 account for 50% of the volume, and particles smaller than Dv50 also account for 50% of the volume. Dv50 can be tested using methods known in the art. As an example, GB / T 19077-2016 can be referenced for characterization testing using a Malvern laser particle size analyzer, such as the Malvern Mastersizer-3000.

[0057] In some embodiments, the particle size Dv50 of the metal oxide particles is 5 to 15 nm.

[0058] By applying the aforementioned particle size of metal oxide particles, their reactivity with active oxygen is further improved, which is beneficial in reducing gas generation and heat generation problems during battery use.

[0059] In some embodiments, the positive electrode lithium replenishing agent includes at least one of the following: Li6CoO4, Li5FeO4, Li3VO4, Li2MoO3, Li2RuO3, Li2MnO3, Li2MnO2, Li2NiO2, Li2CuO2, Li2Cu x Ni 1-x M y O2, where 0 < x < 1, 0 ≤ y < 0.1, and M is selected from one or more of Zn, Sn, Mg, Fe and Mn.

[0060] By using the above-mentioned positive electrode lithium replenisher, its chemical properties in generating active oxygen are more suitable for matching the metal oxide particles in the embodiments of this application, so that the generated active oxygen can be almost completely consumed by the metal oxide, which is beneficial to improving the battery's capacity and safety performance.

[0061] In some embodiments, the particle size Dv50 of the positive electrode lithium replenisher is 1 to 20 μm, and can be selected, for example, from about 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, etc.

[0062] In some embodiments, the positive electrode material layer further includes a positive electrode active material, wherein the particle size Dv50 of the positive electrode active material is 0.1 to 20 μm, and can be selected, for example, from about 0.1 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, etc.

[0063] By selecting more suitable particle sizes for the positive electrode lithium replenisher and / or the positive electrode active material, it is beneficial to obtain better battery capacity improvement.

[0064] In some embodiments, the positive electrode material layer further includes a positive electrode active material, and the ratio of the particle size Dv50 of the positive electrode lithium supplement to the particle size Dv50 of the positive electrode active material is A, 1≤A≤12; for example, A can be selected from about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0065] The ratio of the positive electrode lithium supplement Dv50 to the positive electrode active material Dv50 affects the lithium-ion conduction capability of the positive electrode. As the ratio A decreases, the ion conduction capability of the positive electrode increases, but this also increases the contact area between the lithium supplement and the electrolyte, potentially leading to more side reactions. When the ratio A is controlled within the range of 1 to 12, a better balance between the ion conduction capability and side reactions of the positive electrode can be achieved, resulting in a superior overall performance.

[0066] In some embodiments, the mass percentage of the positive electrode lithium supplement in the positive electrode material layer is W1, where 0.1% ≤ W1 ≤ 10%; for example, W1 can be selected from approximately 0.1%, 0.2%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, etc.

[0067] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0068] In some embodiments, the positive electrode active material may be a known positive electrode active material for lithium-ion batteries. As an example, the positive electrode active material may include at least one of the following materials: lithium phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05At least one of O2 and its modified compounds. Examples of lithium phosphates with an olivine structure include, but are not limited to, lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0069] In some embodiments, the positive electrode material layer may optionally include a binder. For example, the binder may include one or more combinations selected from the group consisting of: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0070] In some embodiments, the positive electrode material layer may optionally include a conductive agent. For example, the conductive agent may include one or more combinations selected from the group consisting of: Super P, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0071] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned positive lithium supplement, metal oxide particles, positive active material, and optional conductive agent, binder and any other components in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0072] [Negative electrode plate]

[0073] The negative electrode sheet includes a negative current collector and a negative electrode material layer disposed on at least one surface of the negative current collector, the negative electrode material layer including a negative electrode active material.

[0074] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0075] In some embodiments, the negative electrode active material layer may employ negative electrode active materials known in the art for lithium-ion batteries. For example, the negative electrode active material includes one or more combinations selected from the group consisting of: natural graphite, artificial graphite, mesophase microcarbon spheres (MCMB), hard carbon, soft carbon, silicon, silicon-carbon composites, Li-Sn alloys, Li-Sn-O alloys, Sn, SnO, SnO2, TiO2-Li4Ti5O 12 Li-Al alloy.

[0076] In some embodiments, the negative electrode material layer may optionally include a binder. For example, the binder may include one or more combinations selected from the group consisting of: styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0077] In some embodiments, the negative electrode material layer may optionally include a conductive agent. For example, the conductive agent may include one or more combinations selected from the group consisting of: Super P, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0078] In some embodiments, the negative electrode material layer may also optionally include other additives. For example, other additives may be thickeners (such as sodium carboxymethyl cellulose (CMC-Na)).

[0079] In some embodiments, the negative electrode sheet can be prepared by dispersing the components of the above-mentioned negative electrode material layer, such as negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0080] [Electrolytes]

[0081] In some embodiments, the battery cell further includes an electrolyte; the electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte, which can be selected according to requirements. The electrolyte can be liquid, gel-like, or solid.

[0082] Liquid electrolytes include electrolyte salts and solvents.

[0083] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0084] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0085] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0086] The gel electrolyte includes a polymer as a backbone network and can be used in conjunction with an ionic liquid-lithium salt.

[0087] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0088] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0089] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium-germanium-phosphorus-sulfur, sulfosilium-germanium), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0090] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0091] [Isolation Component]

[0092] In some embodiments, the electrode assembly further includes a spacer disposed between the positive electrode and the negative electrode.

[0093] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0094] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0095] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0096] [Structure of the electrode assembly]

[0097] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0098] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0099] In some implementations, the electrode assembly is a stacked structure.

[0100] As an example, multiple positive and negative electrode plates can be set, and multiple positive and multiple negative electrode plates can be stacked alternately.

[0101] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0102] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0103] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0104] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0105] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0106] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0107] [shell]

[0108] In some embodiments, the battery cell may include a casing. The casing may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc. In some embodiments, the casing may be a sealed structure or a non-sealed structure. As an example, when the casing is a non-sealed structure, the casing serves to protect the electrode assembly, and a sealing bag is included between the casing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag may be a bag-shaped insulating component or an aluminum-plastic film. When the casing is a sealed structure, it is used to encapsulate components such as the electrode assembly and electrolyte.

[0109] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not impose any particular limitations. For example, Figure 1 This is an example of a square-shell battery cell 5.

[0110] In some implementations, refer to Figure 2 The outer casing includes an end cap 53 and a housing 51. The housing 51 has an opening, and the end cap 53 covers the opening. The housing 51 may have one or more openings. The end cap 53 may also have one or more. The positive electrode, negative electrode, and separator may be formed into an electrode assembly 52 by a winding process or a stacking process. The electrode assembly 52 is encapsulated within a receiving cavity formed by the housing 51 and the end cap 53. The electrolyte is immersed in the electrode assembly 52.

[0111] [Electrode terminals]

[0112] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab. The electrode terminal can be directly connected to the tab, or it can be indirectly connected to the tab through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0113] [Pressure relief mechanism]

[0114] In some embodiments, a pressure relief mechanism is provided on the casing. The pressure relief mechanism is used to release the internal gas of the battery cell.

[0115] As an example, the internal pressure or temperature of a battery cell is actuated to release the internal pressure or temperature when it reaches a predetermined threshold. When the internal pressure or temperature of the battery cell reaches the predetermined threshold, the pressure relief mechanism is activated or a weak structure in the pressure relief mechanism is broken, thereby forming an opening or channel for the internal pressure or temperature to be released. The threshold design varies depending on the design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell.

[0116] As an example, the pressure relief mechanism can be integrally molded with the housing.

[0117] As an example, the pressure relief mechanism can also be separately installed and connected to the housing.

[0118] The term "actuation" as used in this application refers to the activation or actuation of the pressure relief mechanism to a certain state, thereby releasing the internal pressure and temperature of the battery cell. The actions of the pressure relief mechanism may include, but are not limited to: movement of components within the mechanism to form an exhaust channel, rupture, breakage, tearing, or opening of at least a portion of the mechanism, etc. When the pressure relief mechanism is activated, the high-temperature, high-pressure substances inside the battery cell are discharged as waste from the activated portion. This method allows for pressure and temperature relief of the battery cell under controllable pressure or temperature, thereby preventing potentially more serious accidents.

[0119] In some embodiments, when the housing is a non-sealed structure, the pressure relief mechanism can be configured as a through hole for venting gas inside the battery cell.

[0120] The emissions from battery cells mentioned in this application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0121] Battery device

[0122] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0123] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0124] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties. Figure 3 This is battery module 4 as an example. (See reference...) Figure 3 In the battery module 4, multiple battery cells 5 can be arranged sequentially along the length of the battery module 4. Of course, they can also be arranged in any other way.

[0125] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0126] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing. Figure 4 and Figure 5 This is battery pack 1 as an example. (See reference...) Figure 4 and Figure 5 The battery pack 1 may include a housing and multiple battery modules 4 disposed within the housing. The housing includes an upper housing 2 and a lower housing 3, with the upper housing 2 covering the lower housing 3 to form a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery pack.

[0127] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0128] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0129] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0130] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0131] Electrical appliances

[0132] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use individual battery cells, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft. Figure 6 This is an example of an electrical device. The electrical device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0133] Example 1

[0134] This embodiment provides a lithium-ion secondary battery, the preparation method of which is as follows:

[0135] (1) Positive electrode plate

[0136] In the positive electrode material layer, the mass percentage of the positive electrode lithium supplement is W1 (3%); based on the mass of the positive electrode lithium supplement, the mass percentage of the metal oxide particles is W2 (0.5%). Lithium iron phosphate (Dv50 of 1.5 μm) as the positive electrode active material, Li5FeO4 (Dv50 of 9 μm) as the positive electrode lithium supplement, CeO2 (Dv50 of 8 nm) as the metal oxide particles, polyvinylidene fluoride (PVDF) as the binder, and acetylene black as the conductive agent are dissolved in N-methylpyrrolidone (NMP) at a mass ratio of 97-(100×W1)-(100×W1×W2):(100×W1):(100×W1×W2):2:1. After thorough mixing, a positive electrode slurry is obtained. The positive electrode slurry is then uniformly coated onto the positive electrode current collector, followed by drying, cold pressing, and slitting to obtain the positive electrode sheet.

[0137] (2) Negative electrode plate

[0138] Artificial graphite as the negative electrode active material, acetylene black as the conductive agent, styrene-butadiene rubber (SBR) as the binder, and sodium carboxymethyl cellulose (CMC) as the thickener are dissolved in deionized water at a mass ratio of 95:2:2:1 and mixed evenly to prepare a negative electrode slurry. The negative electrode slurry is then evenly coated onto a copper foil for the negative electrode current collector, dried to obtain a negative electrode film, and then cold-pressed and slit to obtain a negative electrode sheet.

[0139] (3) Preparation of electrolyte

[0140] In an argon atmosphere glove box (H2O < 0.1 ppm, O2 < 0.1 ppm), 1 mol / L LiPF6 was dissolved in an organic solvent (EC / DMC / EMC = 1 / 1 / 1) and stirred until homogeneous to obtain the corresponding electrolyte.

[0141] (4) Preparation of the isolation membrane: conventional polypropylene membrane is used as the isolation membrane.

[0142] (5) Preparation of lithium-ion batteries

[0143] The positive electrode, separator, and negative electrode are stacked in sequence, with the separator positioned between the positive and negative electrodes to provide isolation. The electrodes are then wound to obtain the electrode assembly. The electrode assembly is placed in the battery casing, dried, and then injected with electrolyte. After formation and settling processes, a lithium-ion battery is obtained.

[0144] The following tests were performed on the lithium-ion batteries, and the test results are shown in Table 1:

[0145] 1. Lithium-ion battery capacity testing

[0146] At 25°C, a lithium-ion battery was charged at a constant current of 0.33C to 3.65V, then charged at a constant voltage of 3.65V until the current was less than 0.05C. Finally, the lithium-ion battery was discharged at a constant current of 0.33C to 2.5V, and its actual capacity was recorded as C0 (mAh). The specific capacity of the lithium-ion battery is C0 / W3 (mAh / g), where W3 is the mass (g) of the positive electrode active material and the positive electrode lithium replenishing agent.

[0147] 2. Cyclic performance (45℃, 80% of cycle time)

[0148] At 45℃, the lithium-ion battery is charged at a constant current of 0.5C to a voltage of 4.45V, then charged at a constant voltage of 4.45V until the current is ≤0.05mA. The battery is then discharged at a constant current of 0.5C to a voltage of 2.5V. This constitutes one charge-discharge cycle, and the discharge capacity at this point is recorded as the discharge capacity of the battery's first cycle. This charge-discharge cycle is repeated, and the number of cycles required to achieve 80% capacity retention is calculated.

[0149] The capacity retention rate (%) of the battery after N cycles at 45℃ = (discharge capacity of the battery in the Nth cycle / discharge capacity of the battery in the first cycle) × 100%.

[0150] Examples 2-5

[0151] Except for the mass percentage W2 of the metal oxide particles relative to the positive electrode lithium replenisher, which is shown in Table 1, the preparation and testing were carried out in the same manner as in Example 1, and the results are shown in Table 1.

[0152] Comparative Example 1

[0153] Except for the absence of metal oxide particles, the preparation and testing were carried out in the same manner as in Example 1, and the results are shown in Table 1.

[0154] Comparative Example 2

[0155] Except for the absence of a positive electrode lithium supplement, the preparation and testing were carried out according to the same steps as in Example 1, and the results are shown in Table 1. The mass ratio of lithium iron phosphate, metal oxide particles, binder, and conductive agent in the positive electrode active material was 97:(100×3%×0.5%):(100×3%×0.5%):2:1.

[0156] Table 1

[0157]

[0158] Examples 6-9

[0159] Except for the Dv50 of the metal oxide particles, which is shown in Table 2, the preparation and testing were carried out in the same manner as in Example 1, and the results are shown in Table 2.

[0160] Table 2

[0161]

[0162]

[0163] Examples 10-12

[0164] Except for the specific materials of the metal oxide particles, as shown in Table 3, the preparation and testing were carried out in the same manner as in Example 1, and the results are shown in Table 3.

[0165] Table 3

[0166]

[0167] Examples 13-14

[0168] Except for the positive electrode lithium replenishment agent and the particle size Dv50 of the positive electrode active material, which are shown in Table 4, the preparation and testing were carried out in the same manner as in Example 1, and the results are shown in Table 4.

[0169] Table 4

[0170]

[0171] Examples 15-16

[0172] Except for the specific materials of the positive electrode lithium replenisher shown in Table 6, the preparation and testing were carried out in the same manner as in Example 1, and the results are shown in Table 6.

[0173] Table 6

[0174]

[0175] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A battery cell, characterized in that, The device includes a positive electrode, a negative electrode, and a separator. The positive electrode includes a positive current collector and a positive electrode material layer disposed on at least one surface of the positive current collector. The positive electrode material layer includes a positive electrode lithium supplement and metal oxide particles. The metal oxide includes at least one of CeO2, TiO2, Cu2O, CuO, WO3, NiO, Fe2O3, Co3O4, MnO, ZnO, MnO2, and MoO3. The mass ratio of the positive electrode lithium supplement to the metal oxide particles is 100:(0.1-20).

2. The battery cell as described in claim 1, characterized in that, The mass ratio of the positive electrode lithium supplement to the metal oxide particles is 100:(0.1-10).

3. The battery cell as described in claim 1 or 2, characterized in that, The particle size Dv50 of the metal oxide particles is 5-50 nm.

4. The battery cell as described in claim 1 or 2, characterized in that, The particle size Dv50 of the metal oxide particles is 5-15 nm.

5. The battery cell according to any one of claims 1 to 4, characterized in that, The positive electrode lithium replenishing agent includes at least one of the following: Li6CoO4, Li5FeO4, Li3VO4, Li2MoO3, Li2RuO3, Li2MnO3, Li2MnO2, Li2NiO2, Li2CuO2, Li2Cu x Ni 1-x M y O2, where 0 < x < 1, 0 ≤ y < 0.1, and M is selected from one or more of Zn, Sn, Mg, Fe and Mn.

6. The battery cell according to any one of claims 1 to 5, characterized in that, The particle size Dv50 of the positive electrode lithium replenishing agent is 1-20 μm.

7. The battery cell according to any one of claims 1 to 6, characterized in that, The positive electrode material layer also includes a positive electrode active material, wherein the particle size Dv50 of the positive electrode active material is 0.1 to 20 μm.

8. The battery cell according to any one of claims 1 to 7, characterized in that, The positive electrode material layer also includes a positive electrode active material, and the ratio of the particle size Dv50 of the positive electrode lithium supplement to the particle size Dv50 of the positive electrode active material is A, where 1≤A≤12.

9. The battery cell according to any one of claims 1 to 8, characterized in that, In the positive electrode material layer, the mass percentage of the positive electrode lithium supplement is W1, where 0.1% ≤ W1 ≤ 10%.

10. A battery device, characterized in that, The battery device comprises the battery cell according to any one of claims 1 to 9.

11. An electrical appliance, characterized in that, The electrical device includes a battery cell as described in any one of claims 1 to 9 or a battery device as described in claim 10.

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