Battery monomer, battery and electric device

Abstract

The embodiment of the invention provides a battery monomer, a battery and an electric device. The battery cell includes: an electrode assembly; an electrolyte; a case for accommodating the electrode assembly and the electrolyte; the battery monomer meets the following conditions: (a), V is the residual volume in the shell in a full discharge state of the battery monomer, and the unit is mL; cAP is the nominal capacity of the single battery, and the unit is Ah; c0 is the theoretical specific capacity of the corresponding alkali metal in the battery monomer, and the unit is mAh / g; rho0 is the theoretical density of the corresponding alkali metal in the battery monomer, and the unit is g / cm < 3 >. According to the technical scheme, the electrolyte leakage caused by the fact that the electrolyte is extruded out due to overlarge change of the electrode assembly can be avoided, and the safety performance of the battery is further improved. # imgabs0 #

Description

Battery cells, batteries and electrical devices Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Art

[0002] In recent years, lithium batteries have been used in an increasingly diverse range of applications, including energy storage systems such as electricity, hydropower, thermal power, and solar power plants, as well as in electric bicycles, electric motorcycles, electric vehicles, military equipment, and aerospace. While lithium batteries have experienced significant growth, higher requirements have been placed on their safety and performance.

[0003] Therefore, how to improve the safety performance of batteries is an urgent problem that needs to be solved.

[0004] Summary of the Invention

[0005] The present application is made in view of the above-mentioned problems, and its purpose is to provide a battery cell, a battery and an electrical device that can improve the safety performance of the battery.

[0006] A first aspect of the present application provides a battery cell, comprising: an electrode assembly; an electrolyte; and a housing for accommodating the electrode assembly and the electrolyte; wherein the battery cell satisfies: Wherein, V is the residual volume of the battery cell in the housing when the battery cell is fully discharged, in mL; CAP is the nominal capacity of the battery cell, in Ah; C0 is the theoretical specific capacity of the corresponding alkali metal in the battery cell, in mAh / g; ρ0 is the theoretical density of the corresponding alkali metal in the battery cell, in g / cm 3 .

[0007] In the embodiment of the present application, the battery cell includes an electrode assembly, an electrolyte, and a shell. The ratio of the remaining volume in the shell to the nominal capacity of the battery cell is not less than 200 to the ratio of the theoretical specific capacity and theoretical density of the corresponding alkali metal in the battery cell. By establishing a relationship between the remaining volume in the shell, the nominal capacity of the battery cell, and the theoretical specific capacity and theoretical density of the corresponding alkali metal in the battery cell through a relationship, when manufacturing the battery cell, sufficient space can be left inside the battery cell to cope with the volume change of the electrode assembly during the charging and discharging process, avoid the leakage of the electrolyte caused by the extrusion of the electrolyte due to excessive changes in the electrode assembly, and thus improve the safety performance of the battery cell.

[0008] In some possible implementations, the battery cell satisfies:

[0009] In the embodiments of this application, to provide sufficient space for the electrode assembly, the ratio of the remaining volume in the housing to the nominal capacity of the battery cell is no less than 200 times the theoretical specific capacity and theoretical density of the corresponding alkali metal in the battery cell. However, if the battery housing volume is too large, it will affect the volumetric energy density of the battery. By ensuring that the ratio of the remaining volume in the housing to the nominal capacity of the battery cell is no more than 4000 times the theoretical specific capacity and theoretical density of the corresponding alkali metal in the battery cell, it is beneficial to improve the safety performance of the battery cell while maintaining a high volumetric energy density of the battery cell.

[0010] In some possible implementations, the battery cell further satisfies at least one of the following conditions: (1) CAP is not less than 1Ah, optionally, 1Ah≤CAP≤300Ah; (2) 500mAh / g≤C0≤3700mAh / g; (3) 0.5g / cm 3 ≤ρ0≤3.0g / cm 3 ; (4) The volume energy density VED of the battery cell satisfies: 100Wh / L≤VED≤600Wh / L.

[0011] In the embodiment of the present application, by ensuring that the CAP, C0, ρ0 and VED of the battery cell meet the above requirements, good battery performance can be ensured.

[0012] In some possible implementations, when the battery cell is a lithium battery cell, the lithium battery cell satisfies at least one of the following conditions: (1) 1500mAh / g≤C0≤3700mAh / g; (2) 0.5g / cm 3 ≤ρ0≤2.0g / cm 3 ; (3) The lithium battery cell is a lithium metal battery cell; (4) The volume energy density VED of the lithium ion battery cell satisfies: 100Wh / L≤VED≤900Wh / L.

[0013] In the embodiment of the present application, by ensuring that the CAP, C0, ρ0 and VED of the battery cell meet the above requirements, good battery performance can be ensured.

[0014] In some possible implementations, when the battery cell is a lithium battery cell, the ratio of V / CAP to 200 / (C0×ρ0) is 2-20 mL / Ah, optionally, 2-10 mL / Ah.

[0015] In the embodiment of the present application, when the battery cell is a lithium battery cell, by maintaining the ratio of V / CAP to 200 / (C0×ρ0) at 2-20mL / Ah, especially 2-10mL / Ah, it is beneficial to improve the safety performance of the battery cell while ensuring a higher volume energy density of the battery cell.

[0016] In some possible embodiments, when the battery cell is a sodium battery cell, the sodium battery cell further satisfies at least one of the following conditions: (1) 400 mAh / g ≤ C0 ≤ 1200 mAh / g; (2) 0.8 g / cm 3 ≤ρ0≤3.5g / cm 3 ; (3) The sodium battery cell is a sodium metal battery cell; (4) The volume energy density VED of the sodium battery cell satisfies: 150Wh / L≤VED≤300Wh / L.

[0017] In the embodiment of the present application, by ensuring that the CAP, C0, ρ0 and VED of the battery cell meet the above requirements, good battery performance can be ensured.

[0018] In some possible implementations, when the battery cell is a sodium battery cell, the ratio of V / CAP to 200 / (C0×ρ0) is 2-30 mL / Ah, optionally, 2-13 mL / Ah.

[0019] In the embodiment of the present application, when the battery cell is a sodium battery, by maintaining the ratio of V / CAP to V / CAP to 200 / (C0×ρ0) at 2-30 mL / Ah, especially 2-13 mL / Ah, it is beneficial to improve the safety performance of the battery cell while ensuring a high volume energy density of the battery cell.

[0020] In some possible implementations, the electrode assembly includes a negative electrode plate; the negative electrode plate includes an alkali metal.

[0021] In the embodiment of the present application, by making the battery cell include an alkali metal negative electrode plate, the technical solution of the present application can also be applied to a battery cell with an alkali metal negative electrode.

[0022] A second aspect of the present application provides a battery, comprising the battery cell described in any one of the embodiments in the first aspect of the present application.

[0023] The third aspect of the present application provides an electrical device, comprising the battery described in the second aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. 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 the drawings without creative work.

[0025] FIG1 is a schematic structural diagram of a battery cell according to an embodiment of the present application;

[0026] FIG2 is a schematic diagram of a battery cell according to an embodiment of the present application;

[0027] FIG3 is a schematic structural diagram of a battery according to an embodiment of the present application;

[0028] FIG4 is a schematic structural diagram of an electric device according to an embodiment of the present application. DETAILED DESCRIPTION

[0029] The following describes in detail embodiments of the battery cell, battery, and electrical device of the present application, with appropriate reference to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially identical structures may be omitted. Furthermore, the accompanying drawings and the following description are provided to facilitate a thorough understanding of the present application by those skilled in the art and are not intended to limit the subject matter of the claims.

[0030] " scope " disclosed in the application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and selected lower limit and upper limit define the boundary of specific range.The scope that this mode limits can be to include end value or not include end value, and can be combined arbitrarily, and promptly any lower limit can form a scope with any upper limit combination.For example, if the scope of 60-120 and 80-110 is listed for specific parameter, it is also expected that the scope of 60-110 and 80-120 is understood to be.In addition, if the minimum range value 1 and 2 listed, and if the maximum range value 3,4 and 5 listed, then the following scope can all be expected to: 1-3,1-4,1-5,2-3,2-4 and 2-5.In the application, unless otherwise specified, numerical range " ab " represents the abbreviation of any real number combination between a and b, and wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0031] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0032] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0033] Unless otherwise specified, all steps of the present 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 may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0034] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0035] The terms "above", "below", "greater than" or "less than" as used in this application are inclusive of the number, for example, "at least one" means one or more, and "at least one of A and B" means "A", "B" or "A and B".

[0036] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0037] Alkali metal batteries, such as lithium and sodium batteries, are widely used in consumer electronics due to their high energy density, high power density, and long cycle life. In recent years, with the continuous development of electric vehicles and energy storage systems, people's understanding of the safety performance of alkali metal batteries has also been continuously improved.

[0038] In existing alkali metal batteries, the electrode assembly inside the battery expands in volume due to continuous charging and discharging. When the volumetric change rate of the electrode assembly is too large, the limited space inside the battery housing cannot accommodate the electrolyte, potentially squeezing it out. When the volumetric change rate of the electrode assembly reaches a certain level, the electrolyte may burst out of the battery at high pressure, posing a certain threat to battery safety. Therefore, developing large-scale energy storage systems with high safety performance is particularly important.

[0039] The battery cell, battery, and electrical device of the present application are described below with reference to the accompanying drawings.

[0040] The battery cells of the present application may be lithium-ion batteries, lithium metal batteries, sodium-ion batteries, etc. The present application does not limit the type of battery, and the following description will take lithium-ion batteries as an example.

[0041] [Battery Cell]

[0042] The first aspect of the present application provides a battery cell 100. FIG1 is a schematic structural diagram of a battery cell according to an embodiment of the present application. As shown in FIG1 , the battery cell 100 includes an electrode assembly 11; an electrolyte; and a housing 12 for accommodating the electrode assembly 11 and the electrolyte. The battery cell 100 meets the following requirements: Wherein, V is the residual volume of the battery cell 100 in the housing 12 when the battery cell 100 is fully discharged, in mL; CAP is the nominal capacity of the battery cell 100, in Ah; C0 is the theoretical specific capacity of the corresponding alkali metal in the battery cell 100, in mAh / g; ρ0 is the theoretical density of the corresponding alkali metal in the battery cell 100, in g / cm 3 .

[0043] Research has found that by making the ratio of V and CAP of the battery cell 100 not less than 200 and the ratio of the theoretical specific capacity and theoretical density of the corresponding alkali metal in the battery cell 100, sufficient space can be left in the shell to cope with the volume change rate of the electrode assembly 11, reducing the probability of the electrolyte being squeezed out of the shell 12 with a greater pressure, thereby improving the safety performance of the battery cell 100.

[0044] By establishing a relationship between the remaining volume in the shell 12, the nominal capacity of the battery cell 100, and the theoretical specific capacity and theoretical density of the corresponding alkali metal in the battery cell 100 in the form of a relationship, sufficient space can be left inside the battery cell 100 when manufacturing the battery cell 100 to cope with the volume change of the electrode assembly 11 during the charging and discharging process, avoiding the leakage of the electrolyte caused by the squeezing out of the electrolyte due to excessive changes in the electrode assembly 11, thereby improving the safety performance of the battery cell 100; at the same time, expressing the relationship as the ratio of volume to nominal capacity can make the relationship universal and normalized.

[0045] It should be noted that V represents the residual volume within the housing 12 of the battery cell 100 when fully discharged. This refers to the residual volume within the housing 12 of the battery cell 100 after removing all materials, including mechanical components, electrode assembly 12, and electrolyte. Mechanical components include, but are not limited to, connectors and safety features. The fully discharged state refers to discharging the battery at a current density of 0.04C until the battery capacity is less than or equal to 1% of the nominal capacity.

[0046] The nominal capacity of the battery cell 100 refers to the product of the total current that can be output by the battery cell 100 when it is fully charged and discharged at a constant current and constant voltage of 0.33C to the termination voltage and the discharge time.

[0047] Additionally, C0 is the theoretical specific capacity of the corresponding alkali metal in battery cell 100. For example, if battery cell 100 is a sodium-ion battery, and its corresponding alkali metal is metallic sodium, C0 is 1166 mAh / g; if battery cell 100 is a lithium-ion battery, and its corresponding alkali metal is metallic lithium, C0 is 3860 mAh / g. The method for determining ρ0 and C0 is the same, so it will not be repeated here.

[0048] in addition, is The 1000 here is the unit conversion relationship between C0 and CAP.

[0049] In some embodiments, the battery cell 100 satisfies:

[0050] In the above solution, to provide sufficient space for the electrode assembly 11, the ratio of the remaining volume in the housing 12 to the nominal capacity of the battery cell 100 is set to be no less than 200 times the theoretical specific capacity and theoretical density of the corresponding alkali metal in the battery cell 100. However, if the battery housing volume is too large, the battery's volumetric energy density will be affected. By ensuring that the ratio of the remaining volume in the housing to the nominal capacity of the battery cell is no more than 4000 times the theoretical specific capacity and theoretical density of the corresponding alkali metal in the battery cell, the battery cell safety performance can be improved while maintaining a high volumetric energy density.

[0051] In some embodiments, in some possible embodiments, the battery cell further satisfies at least one of the following conditions: (1) CAP is not less than 1Ah, optionally, 1Ah≤CAP≤300Ah; (2) 500mAh / g≤C0≤3700mAh / g; (3) 0.5g / cm 3 ≤ρ0≤3.0g / cm 3 ; (4) The volume energy density VED of the battery cell satisfies: 100Wh / L≤VED≤600Wh / L.

[0052] In the above solution, by ensuring that the CAP, C0, ρ0 and VED of the battery cells meet the above requirements, good battery performance can be guaranteed.

[0053] For example, the C0 of Li is 3680 mAh / g, the C0 of Na is 1165 mAh / g, and the C0 of K is 687 mAh / g.

[0054] For example, the ρ0 of Li is 0.534 g / cm3 , ρ0 of Na is 0.97 g / cm 3 , ρ0 of K is 0.86 g / cm 3 .

[0055] In some embodiments, when the battery cell 100 is a lithium battery cell, the lithium battery cell 100 satisfies at least one of the following conditions: (1) 1500mAh / g≤C0≤3700mAh / g; (2) 0.5g / cm 3 ≤ρ0≤2.0g / cm 3 ; (3) The lithium battery cell is a lithium metal battery cell; (4) The volume energy density VED of the lithium battery cell satisfies: 100Wh / L≤VED≤900Wh / L.

[0056] In the above solution, by ensuring that the CAP, C0, ρ0 and VED of the battery cell 100 meet the above requirements, good battery performance can be ensured.

[0057] In some embodiments, when the battery cell is a lithium battery cell, the ratio of V / CAP to 200 / (C0×ρ0) is 2-20 mL / Ah, optionally, 2-10 mL / Ah.

[0058] In the above scheme, when the battery cell 100 is a lithium battery, by maintaining the ratio of V / CAP to 200 / (C0×ρ0) at 2-20mL / Ah, especially 2-10mL / Ah, it is beneficial to improve the safety performance of the battery cell while ensuring a high volume energy density of the battery cell.

[0059] In some embodiments, when the battery cell 100 is a sodium battery cell, the sodium battery cell further satisfies at least one of the following conditions: (1) 400 mAh / g ≤ C0 ≤ 1200 mAh / g; (2) 0.8 g / cm 3 ≤ρ0≤3.5g / cm 3 ; (3) The sodium battery cell is a sodium metal battery cell; (4) The volume energy density VED of the sodium battery cell satisfies: 150Wh / L≤VED≤300Wh / L.

[0060] In the above solution, by ensuring that the CAP, C0, ρ0 and VED of the battery cells meet the above requirements, the battery can be guaranteed to have a higher energy density.

[0061] In some embodiments, when the battery cell 100 is a sodium battery cell, the ratio of V / CAP to 200 / (C0×ρ0) is 2-30 mL / Ah, optionally 2-13 mL / Ah.

[0062] In the above scheme, when the battery cell 100 is a sodium battery cell, by maintaining the ratio of V / CAP to 200 / (C0×ρ0) at 2-30 mL / Ah, especially 2-13 mL / Ah, it is beneficial to improve the safety performance of the battery cell while ensuring a high volume energy density of the battery cell.

[0063] In some embodiments, the electrode assembly 11 includes a negative electrode sheet, and the negative electrode sheet includes an alkali metal.

[0064] The negative electrode plate includes an alkali metal, and the alkali metal may already be present in the negative electrode plate before charging, or the alkali metal may be present in the negative electrode plate during charging. In other words, the negative electrode plate may directly contain an alkali metal layer, or the alkali metal layer may be deposited on the surface of the negative electrode plate during the battery cell 100 cycles.

[0065] In the above solution, by making the battery cell include a negative electrode plate of an alkali metal, the technical solution of the present application can also be applied to a battery cell with an alkali metal negative electrode.

[0066] In addition, the type of alkali metal may be determined based on the type of ions that can reversibly work in the positive electrode active material.

[0067] [Positive electrode]

[0068] The positive electrode sheet includes a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector, wherein the positive electrode film layer includes a positive electrode active material.

[0069] As an example, the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive electrode current collector.

[0070] In some embodiments, the positive electrode 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 material base and a metal layer formed on at least one surface of the polymer material base. 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 material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0071] In some embodiments, the positive electrode active material may adopt the positive electrode active material for batteries that is well known in the art. As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries 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 may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and its modified compounds. Examples of olivine-structured lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0072] In some embodiments, the positive electrode active material may also include at least one of the following materials: a sodium transition metal oxide, a polyanionic compound, and a Prussian blue compound. However, this application is not limited to these materials; other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more.

[0073] In some embodiments, the transition metal in the sodium transition metal oxide may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce. For example, the sodium transition metal oxide is Na x MO2, wherein M is one or more of Ti, V, Mn, Co, Ni, Fe, Cr and Cu, and 0<x≤1.

[0074] In some embodiments, the polyanionic compound may be a compound having sodium ions, transition metal ions and tetrahedral (YO4) n- A class of compounds with anionic units. The transition metal can be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce; Y can be at least one of P, S and Si; n represents (YO4) n- valence.

[0075] Polyanionic compounds can also be sodium ions, transition metal ions, tetrahedral (YO4) n- A class of compounds of anion units and halogen anions. The transition metal may include at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce; Y may include at least one of P, S and Si, and n represents (YO4) n- valence state; the halogen may include at least one of F, Cl and Br.

[0076] Polyanionic compounds can also be sodium ions, tetrahedral (YO4) n- Anion unit, polyhedron unit (ZO y ) m+ and an optional halogen anion. Y may include at least one of P, S and Si, and n represents (YO4) n- valence state; Z represents a transition metal, including at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce, m represents (ZO y ) m+ valence state; halogen may include at least one of F, Cl and Br.

[0077] Polyanionic compounds include NaFePO4, Na3V2(PO4)3 (sodium vanadium phosphate, abbreviated as NVP), Na4Fe3(PO4)2(P2O7), NaM'PO4F (M' includes one or more of V, Fe, Mn and Ni) and Na3(VO y )2(PO4)2F 3-2y At least one of (0≤y≤1).

[0078] Prussian blue compounds can be sodium ions, transition metal ions and cyanide ions (CN - ) compounds. The transition metal may include at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce. Prussian blue compounds are, for example, Na a Me b Me' c (CN)6, wherein Me and Me' are each independently at least one of Ni, Cu, Fe, Mn, Co and Zn, 0<a≤2, 0<b<1, 0<c<1.

[0079] In some embodiments, the positive electrode film layer may further optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorinated acrylate resin.

[0080] In some embodiments, the positive electrode film layer may further include a conductive agent. For example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0081] In some embodiments, the positive electrode sheet can be prepared by the following method: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components, are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0082] The positive electrode sheet of the present application does not exclude other additional functional layers in addition to the positive electrode film layer. For example, in some embodiments, the positive electrode sheet of the present application further includes a conductive primer layer (e.g., composed of a conductive agent and a binder) sandwiched between the positive electrode current collector and the positive electrode film layer and disposed on the surface of the positive electrode current collector. In other embodiments, the positive electrode sheet of the present application further includes a protective layer covering the surface of the positive electrode film layer.

[0083] [Negative electrode]

[0084] The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer provided on at least one surface of the negative electrode current collector, wherein the negative electrode film layer includes a negative electrode active material.

[0085] As an example, the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0086] 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 base layer 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.), or a current collector that combines support capabilities with functional elements, such as carbon cloth, carbon film, carbonaceous, porous current collector, alloyed modified current collector, lithium / sodium-philic modified current collector.

[0087] In some embodiments, the negative electrode plate can be a rolled metal foil or a surface coated with an inert layer of metal powder coated on the current collector; it can be a functional coating negative electrode, such as a carbon material coating (including single-arm, multi-arm conductive carbon tubes, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers, soft carbon and hard carbon, etc.), lithium-philic / sodium-philic metal composite coating, etc.

[0088] In some embodiments, the negative electrode plate is an alkali metal negative electrode. The alkali metal negative electrode can be a current collector with an alkali metal layer pre-applied thereon, or it can be a negative electrode current collector that forms an alkali metal layer on the negative electrode current collector during charge and discharge. This application is not limited to this.

[0089] In some embodiments, the negative electrode active material may be a negative electrode active material for a battery that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxides, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0090] In some embodiments, the negative electrode film layer may further include a binder. The binder may be selected from at least one 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).

[0091] In some embodiments, the negative electrode film layer may further include a conductive agent, which may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0092] In some embodiments, the negative electrode film layer may optionally include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).

[0093] In some embodiments, the negative electrode sheet can be prepared by the following method: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components, are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.

[0094] [Electrolytes]

[0095] The electrolyte conducts ions between the positive and negative electrodes. This application does not specify the type of electrolyte, and the electrolyte can be selected based on the needs. For example, the electrolyte can be liquid, gel, or solid.

[0096] In some embodiments, the electrolyte is an electrolyte solution comprising an electrolyte salt and a solvent.

[0097] In some embodiments, as an example, the electrolyte salt may be a lithium salt, including at least one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bisfluorosulfonyl imide (LiFSI, LiN(FSO2)2), lithium bistrifluoromethanesulfonyl imide (LiN(CF3SO2)2), lithium trifluoromethanesulfonate (CF3SO3Li), lithium difluorophosphate (LiPO2F2), lithium difluorooxalatoborate (LiDFOB, LiBC2O4F2), lithium dioxalatoborate (LiBOB, LiB(C2O4)2), lithium difluorodioxalatophosphate (LiDODFP, Li(C2O4)2PF2) and lithium tetrafluorooxalatophosphate (LiOTFP, LiC2O4PF4).

[0098] In some embodiments, as an example, the electrolyte salt may be a sodium salt, including but not limited to at least one of NaPF6, NaClO4, NaBCl4, NaSO3CF3, and Na(CH3)C6H4SO3. One of the sodium salts may be used alone, or two or more may be used simultaneously.

[0099] In some embodiments, as an example, the organic solvent includes but is not limited to at least one of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS) and diethyl sulfone (ESE). The above organic solvents can be used alone or in combination. Alternatively, two or more organic solvents are used in combination.

[0100] In some embodiments, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.

[0101] In some embodiments, as an example, the additive includes but is not limited to at least one of fluoroethylene carbonate (FEC), vinylene carbonate (VC), vinyl ethylene carbonate (VEC), diethylene sulfate (DTD), propylene sulfate, vinyl sulfite (ES), 1,3-propane sultone (PS), 1,3-propene sultone (PST), sulfonate cyclic quaternary ammonium salt, succinic anhydride, succinonitrile (SN), adiponitrile (AND), tris(trimethylsilyl) phosphate (TMSP), and tris(trimethylsilyl) borate (TMSB).

[0102] The electrolyte solution can be prepared according to conventional methods in the art. For example, an organic solvent, a sodium electrolyte salt, and optional additives can be uniformly mixed to obtain the electrolyte solution. The order in which the materials are added is not particularly limited. For example, the sodium electrolyte salt and the optional additives can be added to the organic solvent and mixed uniformly to obtain the electrolyte solution; alternatively, the sodium electrolyte salt can be first added to the organic solvent, and then the optional additives can be added to the organic solvent and mixed uniformly to obtain the electrolyte solution.

[0103] [Isolation film]

[0104] In some embodiments, the secondary battery further includes a separator. This separator is positioned between the positive and negative electrode sheets, primarily preventing short circuits between the positive and negative electrodes while allowing active ions to pass through. This application does not specifically limit the type of separator; any known porous separator with good chemical and mechanical stability may be used.

[0105] In some embodiments, the material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. 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.

[0106] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator can be formed into the electrode assembly 12 by a winding process or a lamination process.

[0107] In some embodiments, the battery cell 100 may include an outer packaging that can be used to encapsulate the electrode assembly 12 and the electrolyte.

[0108] In some embodiments, the outer packaging of the battery cell 100 may be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. Alternatively, the outer packaging of the secondary battery may be a soft shell, such as a pouch-type soft shell. The soft shell may be made of plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0109] The present application has no particular limitation on the shape of the battery cell 100 , which may be cylindrical, square, or any other shape. For example, FIG2 is a schematic diagram of a battery cell according to an embodiment of the present application.

[0110] Please continue to refer to Figure 1. In some embodiments, the outer packaging may include a shell 12 and a cover plate 13. The shell 12 may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose a receiving cavity. The shell 12 has an opening connected to the receiving cavity, and the cover plate 13 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation membrane can form an electrode assembly 11 through a winding process or a lamination process. The electrode assembly 11 is encapsulated in the receiving cavity. The number of electrode assemblies 11 contained in the battery cell 100 can be one or more, and those skilled in the art can select according to specific actual needs.

[0111] Figure 3 is a schematic diagram of the structure of a battery 300 according to one embodiment of the present application. As shown in Figure 3 , in battery 300, multiple battery cells 100 may be arranged sequentially along the length of battery 300. Of course, they may also be arranged in any other manner. Furthermore, the multiple battery cells 100 may be secured together using fasteners.

[0112] Continuing with Figure 3 , a battery 300 may include a battery box and a plurality of battery cells 100 disposed within the battery box. The battery box includes an upper box body 301 and a lower box body 302. The upper box body 301 can cover the lower box body 302 and form an enclosed space for accommodating the battery cells 100. The plurality of battery cells 100 may be arranged in any manner within the battery box.

[0113] In some embodiments, the battery cells 100 may be assembled into a battery module first. The battery module may contain one or more battery cells 100. The specific number may be selected by those skilled in the art according to the application and capacity of the battery module.

[0114] In addition, the present application also provides an electric device, which includes at least one of the battery cells or batteries provided in the present application. The battery cells or batteries can be used as the power source of the electric device, and can also be used as the energy storage unit of the electric device. The electric device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited thereto.

[0115] For example, FIG4 is a schematic structural diagram of a vehicle according to an embodiment of the present application. As shown in FIG4 , the vehicle 1 can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A motor 400, a controller 600 and a battery 300 can be provided inside the vehicle 1, and the controller 600 is used to control the battery 300 to supply power to the motor 400. For example, a battery 300 can be provided at the bottom, front or rear of the vehicle 1. The battery 300 can be used to power the vehicle 1, for example, the battery 300 can be used as an operating power source for the vehicle 1, for the circuit system of the vehicle 1, for example, for the working power requirements during the start-up, navigation and operation of the vehicle 1. In another embodiment of the present application, the battery 300 can not only be used as an operating power source for the vehicle 1, but also as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0116] As the electrical device, a battery cell or a battery can be selected according to its usage requirements.

[0117] The electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the electric device's requirements for high power and high energy density of the battery, a battery cell or a battery can be used.

[0118] Another example device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is usually required to be lightweight and thin, and may use a battery cell as a power source.

[0119] [Example]

[0120] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0121] 1. Preparation of lithium-ion batteries

[0122] [Example 1]

[0123] 1.1) Preparation of the positive electrode: LiFePO4 (LFP), conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) are dissolved in solvent N-methylpyrrolidone (NMP) in a weight ratio of 97%:1%:2%, and the mixture is thoroughly stirred and mixed to prepare a positive electrode slurry; the positive electrode slurry is evenly coated on the positive electrode current collector aluminum foil, and then dried, cold pressed, and cut to obtain a positive electrode sheet.

[0124] 1.2) Preparation of negative electrode: Active material artificial graphite, conductive agent acetylene black, binder styrene-butadiene rubber (SBR), thickener sodium carbon methyl cellulose (CMC) are mixed thoroughly in an appropriate amount of deionized water solvent system in a weight ratio of 97.5%:0.7%:1.8%:1%, and then coated on Cu foil, dried, and cold pressed to obtain a negative electrode sheet.

[0125] 1.3) Electrolyte: Ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed in a mass ratio of 30%:70% and dissolved in 1M LiPF6 lithium salt.

[0126] 1.4). Diaphragm: 20μm PE porous polymer film.

[0127] 1.5) Assembly: The positive electrode sheet, separator, and negative electrode sheet are stacked in order, with the separator positioned between the positive and negative electrodes to provide separation. Winding is performed to form an electrode assembly, which is then placed in a pre-designed housing and filled with electrolyte. The lithium-ion battery is then hot-pressed at 100°C and 250 MPa for 2 minutes. This battery has a V of 159 mL, a CAP of 215 Ah, and a V / CAP ratio of 0.740 mL / Ah.

[0128] [Example 2]

[0129] The preparation method of the lithium-ion battery of Example 2 is basically the same as that of Example 1, except that V is 218 mL, CAP is 203 Ah, and V / CAP is 1.074 mL / Ah.

[0130] [Example 3]

[0131] The preparation method of the lithium-ion battery of Example 3 is substantially the same as that of Example 1, except that V is 286.46 mL, CAP is 195 Ah, and V / CAP is 1.469 mL / Ah.

[0132] [Example 4]

[0133] The preparation method of the lithium-ion battery of Example 4 is basically the same as that of Example 1, except that V is 333 mL, CAP is 185 Ah, and V / CAP is 1.800 mL / Ah.

[0134] [Example 5]

[0135] The preparation method of the lithium ion battery of Example 5 is substantially the same as that of Example 4, except that the volume V is 183.61 mL and the V / CAP is 0.992 mL / Ah.

[0136] [Example 6]

[0137] The preparation method of the lithium ion battery of Example 6 is basically the same as that of Example 4, except that the volume V is 149 mL and the V / CAP is 0.805 mL / Ah.

[0138] [Example 7]

[0139] The preparation method of the lithium ion battery of Example 7 is substantially the same as that of Example 1, except that the volume V is 138.25 mL and the V / CAP is 0.643 mL / Ah.

[0140] [Example 8]

[0141] The preparation method of the lithium ion battery of Example 8 is basically the same as that of Example 1, except that the volume V is 184 mL and the V / CAP is 0.856 mL / Ah.

[0142] [Example 9]

[0143] The preparation method of the lithium-ion battery of Example 9 is basically the same as that of Example 1, except that the volume V is 300 mL, the CAP is 295 Ah, and the V / CAP is 1.017 mL / Ah.

[0144] [Example 10]

[0145] The preparation method of the lithium ion battery of Example 10 is substantially the same as that of Example 1, except that the volume V is 308 mL, the CAP is 312 Ah, and the V / CAP is 0.987 mL / Ah.

[0146] [Example 11]

[0147] The preparation method of the lithium ion battery of Example 11 is substantially the same as that of Example 1, except that the volume V is 114.03 mL and the V / CAP is 0.530 mL / Ah.

[0148] [Example 12]

[0149] The preparation method of the lithium ion battery of Example 12 is basically the same as that of Example 1, except that the volume V is 126.06 mL, the CAP is 286.5 Ah, and the V / CAP is 0.440 mL / Ah.

[0150] [Example 13]

[0151] The preparation method of the lithium ion battery of Example 13 is basically the same as that of Example 1, except that the volume V is 305.20 mL, the CAP is 145 Ah, and the V / CAP is 2.105 mL / Ah.

[0152] [Example 14]

[0153] The preparation method of the lithium ion battery of Example 14 is basically the same as that of Example 1, except that the volume V is 355.40 mL, the CAP is 132.6 Ah, and the V / CAP is 2.680 mL / Ah.

[0154] [Example 15]

[0155] The preparation method of the sodium ion battery of Example 15 is basically the same as that of Example 10, except that: (1) Preparation of the positive electrode: the active material sodium vanadium phosphate (Na3V2(PO4)3), the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) are dissolved in a solvent N-methylpyrrolidone (NMP) in a weight ratio of 97%:1%:2%, and the mixture is fully stirred and mixed to prepare a positive electrode active material; the positive electrode active material is evenly coated on the positive electrode current collector aluminum foil, and then dried, cold pressed, and cut to obtain a positive electrode sheet; (2) Electrolyte: Ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a mass ratio of 30%:70% and dissolved in 1M sodium salt of NaPF6; (3) V is 217.04mL, CAP is 116Ah, and V / CAP is 1.871mL / Ah.

[0156] [Example 16]

[0157] The preparation method of the sodium ion battery of Example 16 is basically the same as that of Example 11, except that: V is 299.69 mL, CAP is 193.6 Ah, and V / CAP is 1.548 mL / Ah.

[0158] [Example 17]

[0159] The preparation method of the sodium ion battery of Example 17 is basically the same as that of Example 11, except that: V is 398.01 mL, CAP is 173.2 Ah, and V / CAP is 2.298 mL / Ah.

[0160] [Example 18]

[0161] The preparation method of the sodium ion battery of Example 18 is basically the same as that of Example 11, except that: V is 166.5 mL, CAP is 150.8 Ah, and V / CAP is 1.104 mL / Ah.

[0162] [Example 19]

[0163] The preparation method of the sodium ion battery of Example 19 is basically the same as that of Example 11, except that: V is 384.79 mL, CAP is 119.5 Ah, and V / CAP is 3.220 mL / Ah.

[0164] [Comparative Example 1]

[0165] The preparation method of the lithium ion battery of Comparative Example 1 is substantially the same as that of Example 1, except that V is 32 mL, CAP is 330 Ah, and V / CAP is 0.097 mL / Ah.

[0166] [Comparative Example 2]

[0167] The preparation method of the sodium ion battery of Comparative Example 2 is basically the same as that of Example 11, except that: V is 20 mL, CAP is 240 Ah, and V / CAP is 0.083 mL / Ah.

[0168] 2) Physical characterization of lithium-ion batteries

[0169] Measurement of the remaining volume V in the battery case when fully discharged

[0170] At room temperature, after mechanical parts, electrode components and other materials are placed in the shell, electrolyte is injected into the shell until it is full. The volume of electrolyte injected is calculated as V1, and the volume of electrolyte required to be added is calculated as V2, then V=V1-V2.

[0171] Table 1 Specific parameters of Examples 1-19 and Comparative Examples 1-2

[0172] 3) Performance characterization of lithium-ion batteries

[0173] 3.1) Negative electrode volume change rate

[0174] At room temperature, the lithium-ion battery was first charged to 3.65V at a constant current of 0.33C. Further, it was charged at a constant voltage of 3.65V to a current of 0.05C. The battery was then discharged at a constant current of 0.33C to 2.5V. This discharge capacity represents the discharge capacity of the lithium-ion battery before high-temperature storage. The battery was then charged to 3.65V at a constant current of 0.33C and then fully charged at a constant voltage of 3.65V to a current of 0.05C. The battery was then stored at 60°C for 60 days. After the storage period, the battery was placed at room temperature, disassembled, and the negative electrode plate was removed. The battery volume was measured using the water displacement method. The negative electrode plate expansion ratio = (volume after storage / volume before storage) × 100%. See Table 2 for the test results.

[0175] 3.2) Battery internal pressure test

[0176] At room temperature, the lithium-ion battery was first charged to 3.65V at a constant current of 0.33C. It was then further charged at a constant voltage of 3.65V until the current reached 0.05C. The battery was then discharged to 2.5V at a constant current of 0.33C. A pressure sensor was inserted into the battery to measure its internal pressure. See Table 2 for the test results.

[0177] 3.3). Explosion-proof valve status test

[0178] At room temperature, the lithium-ion battery was first charged to 3.65V at a constant current of 0.33C, then further charged at a constant voltage of 3.65V to a current of 0.05C, and then discharged at a constant current of 0.33C to 2.5V. The lithium-ion battery was placed at room temperature and the status of the explosion-proof valve was observed. The test results are shown in Table 2.

[0179] 3.4) Battery volume energy density (VED) test

[0180] At room temperature, charge the battery at a constant current of 0.33C to the full charge voltage, then charge it at the full charge voltage to a current ≤ 0.05C. Discharge the battery at a constant current of 0.33C to the full discharge voltage to obtain the discharge energy Q. Measure the length, width, and height of the battery casing and calculate the battery volume V. The specific values ​​of the full charge voltage and full discharge voltage of each battery cell can be determined by referring to the factory design of the battery cell or by the usual upper and lower charge and discharge cutoff voltages corresponding to the positive electrode material of the battery cell. The volumetric energy density (VED) of the battery is calculated as: discharge energy Q / battery volume V. The unit of volumetric energy density is Wh / L.

[0181] Table 2 Battery performance of Examples 1-19 and Comparative Examples 1-2

[0182] According to Examples 1-19 and Comparative Examples 1-2, when V / CAP is not less than 200 / (C0×ρ0), the volume change rate of the negative electrode plate of the battery is within the normal range, the internal pressure of the battery is low, and the battery explosion-proof valve is not broken. In other words, by increasing the battery V / CAP to greater than 200 / (C0×ρ0), the battery safety performance can be improved.

[0183] It can be seen from Examples 1-12 and Examples 13-17 that the technical solution of the present application can be applied to a variety of battery systems.

[0184] According to Examples 1-19, when V / CAP is no greater than 4000 / (C0×ρ0), the volume change rate of the negative electrode plate and the internal pressure of the battery are small, and the battery's explosion-proof valve is not broken, but the battery's volumetric energy density is low. That is, by ensuring that the battery's V / CAP is no less than 200 / (C0×ρ0), and further, no greater than 4000 / (C0×ρ0), the battery's safety performance can be improved while also achieving a higher volumetric energy density.

[0185] According to Examples 1-14, when the battery cell is a lithium battery cell, by maintaining the ratio of V / CAP to 200 / (C0×ρ0) at 2-20 mL / Ah, especially 2-10 mL / Ah, the battery can have both safety performance and high volume energy density.

[0186] According to Examples 15-19, when the battery cell is a sodium battery cell, by maintaining the ratio of V / CAP to 200 / (C0×ρ0) at 2-30 mL / Ah, especially 2-13 mL / Ah, the battery can have both safety performance and high volume energy density.

[0187] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A battery cell, include: Electrode assembly; Electrolytes; A housing for accommodating the electrode assembly and the electrolyte; The battery cell meets the following requirements: in, V is the remaining volume in the housing when the battery cell is fully discharged, in mL; CAP is the nominal capacity of the battery cell, unit: Ah; C 0 is the theoretical specific capacity of the corresponding alkali metal in the battery monomer, unit: mAh / g; ρ 0 is the theoretical density of the corresponding alkali metal in the battery cell, unit: g / cm 3 .

2. The battery cell according to claim 1, in, The battery cell meets the following requirements:

3. The battery cell according to claim 1 or 2, in, The battery cell also satisfies at least one of the following conditions: (1) CAP is not less than 1Ah, optionally, 1Ah≤CAP≤300Ah; (2)500mAh / g≤C 0 ≤3700mAh / g; (3)0.5g / cm 3 ≤ρ 0 ≤3.0g / cm 3 ; (4) The volume energy density VED of the battery cell satisfies: 100Wh / L≤VED≤600Wh / L.

4. The battery cell according to any one of claims 1 to 3, in, In the case where the battery cell is a lithium battery cell, the lithium battery cell satisfies at least one of the following conditions: (1)1500mAh / g≤C 0 ≤3700mAh / g; (2)0.5g / cm 3 ≤ρ 0 ≤2.0g / cm 3 ; (3) The lithium battery cell is a lithium metal battery cell; (4) The volume energy density VED of the lithium battery cell satisfies: 100Wh / L≤VED≤900Wh / L.

5. The battery cell according to any one of claims 1 to 4, in, In the case where the battery cell is a lithium battery cell, V / CAP and 200 / (C 0 ×ρ 0 ) has a ratio of 2-20 mL / Ah, optionally 2-10 mL / Ah.

6. The battery cell according to any one of claims 1 to 3, in, In the case where the battery cell is a sodium battery cell, the sodium battery cell at least satisfies any one of the following conditions: (1)400mAh / g≤C 0 ≤1200mAh / g; (2)0.8g / cm 3 ≤ρ 0 ≤3.5g / cm 3 ; (3) The sodium battery monomer is a sodium metal battery monomer; (4) The volume energy density VED of the sodium battery monomer satisfies: 150Wh / L≤VED≤300Wh / L.

7. The battery cell according to any one of claims 1 to 3 and 6, in, In the case where the battery cell is a sodium battery cell, V / CAP and 200 / (C 0 ×ρ 0 ) has a ratio of 2-30 mL / Ah, optionally 2-13 mL / Ah.

8. The battery cell according to any one of claims 1 to 7, in, The electrode assembly includes a negative electrode plate, and the negative electrode plate includes an alkali metal.

9. A battery, in, include: A plurality of battery cells according to any one of claims 1 to 8.

10. An electrical device, in, include: The battery as claimed in claim 9, wherein the battery is used to provide electrical energy.

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