WO2023197858A1 - 电池单体、电池以及用电装置 - Google Patents

电池单体、电池以及用电装置 Download PDF

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Publication number
WO2023197858A1
WO2023197858A1 PCT/CN2023/084267 CN2023084267W WO2023197858A1 WO 2023197858 A1 WO2023197858 A1 WO 2023197858A1 CN 2023084267 W CN2023084267 W CN 2023084267W WO 2023197858 A1 WO2023197858 A1 WO 2023197858A1
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WO
WIPO (PCT)
Prior art keywords
battery cell
electrode assembly
along
buffer
buffer member
Prior art date
Application number
PCT/CN2023/084267
Other languages
English (en)
French (fr)
Inventor
张涛
何建福
刘倩
崔陈
孙雪阳
叶永煌
Original Assignee
宁德时代新能源科技股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication of WO2023197858A1 publication Critical patent/WO2023197858A1/zh

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0404—Machines for assembling batteries
    • H01M10/0409—Machines for assembling batteries for cells with wound electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0431—Cells with wound or folded electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/233—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders characterised by physical properties of casings or racks, e.g. dimensions
    • H01M50/242—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders characterised by physical properties of casings or racks, e.g. dimensions adapted for protecting batteries against vibrations, collision impact or swelling
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/471—Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/471—Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof
    • H01M50/474—Spacing elements inside cells other than separators, membranes or diaphragms; Manufacturing processes thereof characterised by their position inside the cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the field of batteries, and in particular to a battery cell, a battery and an electrical device.
  • Battery cells are widely used in electronic devices, such as mobile phones, laptops, battery cars, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, electric tools, etc.
  • the battery cells may include cadmium-nickel battery cells, nickel-hydrogen battery cells, lithium-ion battery cells, secondary alkaline zinc-manganese battery cells, etc.
  • This application provides a battery cell, its manufacturing method and manufacturing system, a battery and an electrical device, which can improve the cycle performance of the battery cell.
  • the present application provides a battery cell, which includes a casing, an electrode assembly and a buffer.
  • the housing includes two first side walls arranged oppositely along a first direction, and a distance between the two first side walls along the first direction is D1.
  • the electrode assembly is contained in the housing.
  • the number of electrode components is set to M, and M is a positive integer greater than 0. In the fully charged state, the sum of the dimensions of the M electrode assemblies along the first direction is D2.
  • the buffer component is accommodated in the casing.
  • the number of buffers is set to N, and N is a positive integer greater than 0.
  • N buffer members and M electrode assemblies are stacked along the first direction.
  • the buffer members are configured to be compressible, and the sum of the dimensions of the N buffer members in an uncompressed state along the first direction is D3.
  • D1, D2 and D3 satisfy: 0.9 ⁇ (D2+D3)/D1 ⁇ 1.5.
  • the buffer member can limit the deformation of the electrode assembly to a certain extent when the battery cell is first charged, improve the uniformity of the force distribution of the electrode assembly, reduce the risk of wrinkles in the pole pieces of the electrode assembly, and extend the length of the electrode assembly. life span.
  • the buffer member is compressed when it is squeezed by the electrode assembly to provide space for the expansion of the electrode assembly, reduce the force between the shell and the electrode assembly, and improve the cycle performance of the electrode assembly.
  • the above technical solution limits the value of (D2+D3)/D1 to 0.9-1.5, which can reduce the risk of wrinkles in the pole pieces, save the amount of buffer parts, increase the energy density of the battery cells, and reduce the expansion force of the electrode assembly. Improve the cycling performance of electrode assemblies.
  • D1, D2 and D3 satisfy: 0.98 ⁇ (D2+D3)/D1 ⁇ 1.25.
  • the first direction is parallel to the thickness direction of the battery cell.
  • D2 and D3 satisfy: D3 ⁇ 0.25 ⁇ D2.
  • the above technical solution can reduce the amount of buffer members, increase the energy density of the battery cells, and improve the cycle performance of the electrode assembly.
  • the electrode assembly includes a first pole piece, and the first pole piece includes a first body and a first tab extending from one end of the first body along a second direction, and the second direction is perpendicular to the first direction.
  • the size of the buffer member along the second direction is H1; the first body is provided with a first active material layer, and the size of the first active material layer along the second direction is H2.
  • H1 and H2 satisfy: H1 ⁇ 0.85 ⁇ H2.
  • the main reason for the expansion of the electrode assembly is the expansion of the active material layer during the charging process.
  • the above technical solution limits the value of H1 to be greater than or equal to 0.85 ⁇ H2, so that the expansion of more than 85% of the area of the first active material layer in the second direction can be absorbed by the buffer to reduce the impact on the first active material layer. pressure to improve the cycle performance of the electrode assembly.
  • the first active material layer includes a base region and a thinned region connected to the base region, and the thickness of the thinned region is smaller than the thickness of the base region.
  • the thinned area is located on a side of the base area close to the first tab. In the second direction, both ends of the buffer member extend beyond the base area.
  • the expansion force generated when the base area expands is greater. Therefore, the above technical solution makes the two ends of the buffer member in the second direction exceed the base area to effectively absorb the expansion of the base area and improve the circulation of the electrode assembly. performance.
  • the electrode assembly further includes a separator, and the separator is stacked with the first body.
  • the size of the spacer along the second direction is H3.
  • H1 and H3 satisfy: H1 ⁇ 1.1 ⁇ H3.
  • the portion of the spacer beyond the spacer will not absorb the expansion of the electrode assembly, but will increase the volume and weight of the buffer.
  • the above technical solution makes the value of H1 less than or equal to 1.1 ⁇ H3, so as to reduce the amount of buffer parts and improve the energy density of the battery cells.
  • both ends of the buffer member do not exceed the isolation member, so as to reduce the amount of buffer members, reduce the risk of interference between the buffer members and other components, and improve the energy density of the battery cells.
  • the electrode assembly includes a straight area and two bending areas, the two bending areas are respectively located on both sides of the straight area along a third direction, and the third direction is perpendicular to the first direction.
  • the size of the buffer member in the third direction is L1
  • the size of the electrode assembly in the third direction in the fully charged state is L2
  • the size of one electrode assembly in the first direction in the fully charged state is D4.
  • L1, L2 and D4 satisfy: L1 ⁇ 0.85(L2-D4).
  • both ends of the buffer member exceed the straight area.
  • the buffer can effectively absorb the expansion of the flat area and improve the cycle performance of the flat area.
  • L1 and L2 satisfy: L1 ⁇ 1.1 ⁇ L2.
  • the portion of the buffer that exceeds the electrode assembly will not absorb the expansion of the electrode assembly, but will instead increase the volume and weight of the buffer.
  • the value of L1 is less than or equal to 1.1 ⁇ L2, so as to reduce the amount of buffer components and improve the energy density of the battery cell.
  • the area of the projection of the buffer member on the inner surface of the first side wall along the first direction is S1
  • the area of the inner surface of the first side wall is S2
  • S1 and S2 satisfy: S1 ⁇ 0.95 ⁇ S2 .
  • the above technical solution can reduce the overall usage of the buffer, provide more space for other components in the casing, and improve the energy density and service life of the battery cells.
  • the size of each buffer member along the first direction in an uncompressed state is D5, and D5 satisfies: 0.1mm ⁇ D5 ⁇ 10mm.
  • the compression ratio f of the buffer member under a pressure of 2 MPa satisfies: 1% ⁇ f ⁇ 99%.
  • a buffer is attached to the electrode assembly.
  • the buffer attached to the electrode assembly can be installed into the housing together with the electrode assembly to simplify the assembly process.
  • the electrode assembly can also limit the shaking of the buffer when the battery cell is subjected to external impact, thereby reducing the risk of the buffer being deflected.
  • a buffer is provided between at least two adjacent electrode assemblies. Placing the buffer between two adjacent electrode assemblies can reduce the risk of the buffer shaking when the battery cell is subjected to external impact.
  • the buffer is a flat plate structure.
  • the flat plate structure is easy to form and can improve the uniformity of force distribution of the electrode assembly when the electrode assembly expands.
  • embodiments of the present application provide a battery, which includes a plurality of battery cells according to any embodiment of the first aspect.
  • embodiments of the present application provide an electrical device, which includes the battery cell according to any embodiment of the first aspect, and the battery cell is used to provide electric energy.
  • embodiments of the present application provide a method for manufacturing a battery cell, which includes: providing a casing, which includes two first side walls oppositely arranged along a first direction; providing an electrode assembly and a buffer; The components and bumpers are installed into the housing.
  • the distance between the two first side walls along the first direction is D1.
  • M electrode components and M is a positive integer greater than 0; in the fully charged state, the sum of the dimensions of the M electrode components along the first direction is D2.
  • N buffer members and N is a positive integer greater than 0; the N buffer members and M electrode assemblies are stacked along the first direction; the buffer members are configured to be compressible, and the N buffer members move along the first direction in an uncompressed state.
  • the sum of the dimensions in one direction is D3.
  • D1, D2 and D3 satisfy: 0.9 ⁇ (D2+D3)/D1 ⁇ 1.5.
  • a battery cell manufacturing system which includes a first providing device, a second providing device, and an assembly device.
  • the first providing device is used to provide a housing, and the housing includes two first side walls arranged oppositely along a first direction.
  • the second providing device is used to provide the electrode assembly and the buffer member.
  • the assembly device is used to install the electrode assembly and buffer into the housing.
  • the distance between the two first side walls along the first direction is D1.
  • M electrode components and M is a positive integer greater than 0; in the fully charged state, the sum of the dimensions of the M electrode components along the first direction is D2.
  • N buffer members There are N buffer members, and N is a positive integer greater than 0; the N buffer members and M electrode assemblies are stacked along the first direction; the buffer members are configured to be compressible, and the N buffer members move along the first direction in an uncompressed state.
  • the sum of the dimensions in one direction is D3.
  • D1, D2 and D3 satisfy: 0.9 ⁇ (D2+D3)/D1 ⁇ 1.5.
  • Figure 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application.
  • FIG. 2 is an exploded schematic diagram of a battery provided by some embodiments of the present application.
  • FIG 3 is an exploded schematic diagram of the battery module shown in Figure 2;
  • Figure 4 is an exploded schematic diagram of a battery cell provided by some embodiments of the present application.
  • Figure 5 is a schematic structural diagram of a battery cell provided by some embodiments of the present application.
  • Figure 6 is a schematic cross-sectional view of an electrode assembly of a battery cell provided by some embodiments of the present application.
  • Figure 7 is a schematic cross-sectional view of a battery cell provided by some embodiments of the present application.
  • Figure 8 is a partial cross-sectional schematic view of the electrode assembly and buffer member of the battery cell provided by some embodiments of the present application.
  • Figure 9 is a schematic structural diagram of a battery cell provided by other embodiments of the present application.
  • Figure 10 is a schematic structural diagram of a battery cell provided by some embodiments of the present application.
  • Figure 11 is a schematic structural diagram of a battery cell provided in some embodiments of the present application.
  • Figure 12 is a schematic flow chart of a manufacturing method of a battery cell provided by some embodiments of the present application.
  • Figure 13 is a schematic block diagram of a battery cell manufacturing system provided by some embodiments of the present application.
  • Figure 14 is a schematic structural diagram of a battery cell provided by some embodiments of the present application.
  • the reference numbers for the specific implementation are as follows: 1. Vehicle; 2. Battery; 3. Controller; 4. Motor; 5. Box; 5a, first box part; 5b, second box part; 5c, accommodation space; 6. battery module; 7. Battery cells; 10. Electrode assembly; 11. First pole piece; 111. First body; 112. First active material layer; 112a. Base area; 112b, thinned area; 12, second pole piece; 13, spacer; 14, main body; 15, first pole tab; 16, second pole tab; 10a, straight area; 10b, bent district; 20. Shell; 21. Shell; 211. First side wall; 212. Second side wall; 22. End cover; 30. Buffer; 40. Electrode terminal; 90. Manufacturing system; 91. First providing device; 92. Second providing device; 93. Assembly device; X, first direction; Y, second direction; Z, third direction.
  • an embodiment means that a particular feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the application.
  • the appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.
  • connection should be understood in a broad sense.
  • connection can be a fixed connection, It can also be detachably connected or integrally connected; it can be directly connected or indirectly connected through an intermediate medium; it can be internal communication between two components.
  • connection can be a fixed connection
  • connection can also be detachably connected or integrally connected; it can be directly connected or indirectly connected through an intermediate medium; it can be internal communication between two components.
  • connection can also be detachably connected or integrally connected; it can be directly connected or indirectly connected through an intermediate medium; it can be internal communication between two components.
  • “Plural” appearing in this application means two or more (including two).
  • battery cells may include lithium ion secondary battery cells, lithium ion primary battery cells, lithium sulfur battery cells, sodium lithium ion battery cells, sodium ion battery cells or magnesium ion battery cells, etc.
  • the embodiments of the present application are not limited to this.
  • the battery cell may be in the shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes, and the embodiments of the present application are not limited to this.
  • the battery mentioned in the embodiments of this application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.
  • the battery mentioned in this application may include a battery module or a battery pack.
  • Batteries generally include a box for packaging one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.
  • the battery cell includes an electrode assembly and an electrolyte.
  • the electrode assembly includes a positive electrode piece, a negative electrode piece and a separator. Battery cells mainly rely on the movement of metal ions between the positive and negative electrodes to work.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer.
  • the positive electrode active material layer is coated on the surface of the positive electrode current collector; the positive electrode current collector includes a positive electrode coating area and a positive electrode tab connected to the positive electrode coating area.
  • the positive electrode coating area The positive electrode active material layer is coated, and the positive electrode tab is not coated with the positive electrode active material layer.
  • the material of the positive electrode current collector can be aluminum, and the positive electrode active material layer includes a positive electrode active material.
  • the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganate, etc.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer.
  • the negative electrode active material layer is coated on the surface of the negative electrode current collector;
  • the negative electrode current collector includes a negative electrode coating area and a negative electrode tab connected to the negative electrode coating area.
  • the negative electrode coating area The negative electrode active material layer is coated, and the negative electrode tab is not coated with the negative electrode active material layer.
  • the negative electrode current collector may be made of copper, and the negative electrode active material layer may include a negative electrode active material.
  • the negative electrode active material may be carbon or silicon.
  • the material of the isolator can be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene), etc.
  • the battery cell also includes a casing, and a receiving cavity for accommodating the electrode assembly is formed inside the casing.
  • the shell can protect the electrode assembly from the outside to prevent external foreign matter from affecting the charging or discharging of the electrode assembly.
  • the electrode assembly will expand; the expanded electrode assembly will squeeze the shell.
  • the shell exerts a reaction force on the electrode assembly to limit the expansion of the electrode assembly. If the force between the electrode assembly and the casing is too large, the electrolyte between the pole pieces may be squeezed out, affecting the cycle performance of the electrode assembly.
  • the inventor installed a buffer in the casing.
  • the buffer can limit the deformation of the electrode assembly to a certain extent when the battery cell is first charged, improve the uniformity of the force distribution of the electrode assembly, and reduce the occurrence of wrinkles on the pole pieces of the electrode assembly. risk and extend the life of the electrode assembly.
  • the buffer member is compressed when it is squeezed by the electrode assembly to provide space for the expansion of the electrode assembly, reduce the force between the shell and the electrode assembly, and improve the cycle performance of the electrode assembly.
  • the inventor set the size of the buffer according to the size of the electrode assembly and the size of the housing to improve the cycle performance of the electrode assembly.
  • the battery cells described in the embodiments of this application are suitable for batteries and electrical devices using the battery cells.
  • Electrical devices can be vehicles, cell phones, portable devices, laptops, ships, spacecraft, electric toys and power tools, etc.
  • Vehicles can be fuel vehicles, gas vehicles or new energy vehicles, and new energy vehicles can be pure electric vehicles, hybrid vehicles or extended-range vehicles, etc.
  • spacecraft include aircraft, rockets, space shuttles, spaceships, etc.
  • electric toys include fixed Type or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc.
  • electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, for example, Electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, planers and more.
  • Electric drills Electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, planers and more.
  • the following embodiments take the electrical device as a vehicle as an example.
  • Figure 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application.
  • a battery 2 is provided inside the vehicle 1 , and the battery 2 can be provided at the bottom, head, or tail of the vehicle 1 .
  • the battery 2 may be used to power the vehicle 1 , for example, the battery 2 may be used as an operating power source for the vehicle 1 .
  • the vehicle 1 may also include a controller 3 and a motor 4.
  • the controller 3 is used to control the battery 2 to provide power to the motor 4, for example, to meet the power requirements for starting, navigation and driving of the vehicle 1.
  • the battery 2 can not only be used as the operating power source of the vehicle 1, but also can be used as the driving power source of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.
  • Figure 2 is an exploded schematic diagram of a battery provided by some embodiments of the present application.
  • the battery 2 includes a case 5 and battery cells (not shown), and the battery cells are accommodated in the case 5 .
  • the box 5 is used to accommodate battery cells, and the box 5 can be of various structures.
  • the box body 5 may include a first box body part 5a and a second box body part 5b.
  • the first box body part 5a and the second box body part 5b cover each other.
  • the first box body part 5a and the second box body part 5b cover each other.
  • the two box portions 5b jointly define an accommodating space 5c for accommodating battery cells.
  • the second box part 5b can be a hollow structure with one end open, and the first box part 5a is a plate-like structure.
  • the first box part 5a is covered with the opening side of the second box part 5b to form a receiving space 5c.
  • first box part 5a and the second box parts 5b can also be a hollow structure with one side open, and the open side of the first box part 5a is covered with the open side of the second box part 5b to form the box 5 having an accommodation space 5c.
  • first box part 5a and the second box part 5b can be in various shapes, such as cylinder, rectangular parallelepiped, etc.
  • a sealing member may also be provided between the first box part 5a and the second box part 5b, such as sealant, sealing ring, etc. .
  • the first box part 5a can also be called an upper box cover, and the second box part 5b can also be called a lower box.
  • the battery 2 there may be one battery cell or a plurality of battery cells. If there are multiple battery cells, the multiple battery cells can be connected in series, in parallel, or in mixed connection. Mixed connection means that multiple battery cells are connected in series and in parallel. Multiple battery cells can be directly connected in series or parallel or mixed together, and then the whole composed of multiple battery cells can be accommodated in the box 5; of course, multiple battery cells can also be connected in series or parallel first or A battery module 6 is formed by a mixed connection, and multiple battery modules 6 are connected in series, parallel, or mixed to form a whole, and are accommodated in the box 5 .
  • FIG. 3 is an exploded schematic diagram of the battery module shown in FIG. 2 .
  • FIG. 3 there are multiple battery cells 7 , and the plurality of battery cells 7 are first connected in series, parallel, or mixed to form the battery module 6 .
  • a plurality of battery modules 6 are connected in series, parallel, or mixed to form a whole, and are accommodated in the box.
  • the plurality of battery cells 7 in the battery module 6 can be electrically connected through bus components to achieve parallel, series or mixed connection of the plurality of battery cells 7 in the battery module 6 .
  • Figure 4 is an exploded schematic diagram of a battery cell provided by some embodiments of the present application
  • Figure 5 is a structural schematic diagram of a battery cell provided by some embodiments of the present application, in which the end cover is omitted
  • Figure 6 is a battery provided by some embodiments of the present application Schematic cross-section of a single electrode assembly.
  • the battery cell 7 in the embodiment of the present application includes a casing 20 , an electrode assembly 10 and a buffer 30 .
  • the housing 20 includes two first side walls 211 oppositely arranged along the first direction X, and the distance between the two first side walls 211 along the first direction X is D1.
  • the number of buffer members 30 is N.
  • the N buffer members 30 are accommodated in the housing 20 and are stacked with the M electrode assemblies 10 along the first direction X.
  • the buffer member 30 is configured to be compressible.
  • the sum of the dimensions of the N buffer members 30 in the uncompressed state along the first direction X is D3, and N is a positive integer greater than 0. D1, D2 and D3 satisfy: 0.9 ⁇ (D2+D3)/D1 ⁇ 1.5.
  • the casing 20 has a hollow structure, and an accommodation cavity for accommodating the electrode assembly 10 and the electrolyte is formed inside.
  • the housing 20 can be in various shapes, such as rectangular parallelepiped, etc.
  • the shape of the shell 20 can be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 has a rectangular parallelepiped structure, a rectangular parallelepiped shell can be used.
  • the housing 20 may be made of hard materials such as aluminum, steel, or plastic, or may be made of aluminum-plastic film, steel-plastic film, or other soft materials.
  • the two first side walls 211 are respectively located on both sides of the accommodation cavity along the first direction X.
  • the size of the accommodation cavity along the first direction X is D1.
  • the value of D1 can be measured in many ways.
  • the value of D1 can be measured using a vernier caliper, or measured using microscopic markings such as mechanical section/surface analysis.
  • the electrode assembly 10 includes a first pole piece 11 and a second pole piece 12 .
  • the electrode assembly 10 mainly relies on metal ions to move between the first pole piece 11 and the second pole piece 12 to work.
  • the electrode assembly 10 further includes a separator 13 , which is used to insulate the first pole piece 11 and the second pole piece 12 .
  • the polarity of the first pole piece 11 and the polarity of the second pole piece 12 are opposite. specifically. One of the first pole piece 11 and the second pole piece 12 is a positive pole piece, and the other one is a negative pole piece.
  • M is a positive integer greater than 0, that is to say, there may be one electrode assembly 10 or multiple electrode assemblies 10 .
  • the plurality of electrode assemblies 10 may be stacked along the first direction X.
  • the electrode assembly 10 In a fully charged state, the electrode assembly 10 will expand. For example, after the battery cell 7 is prepared, the battery cell 7 is charged at a rate of 0.33C in a normal temperature environment until it is fully charged. After the battery cell 7 is fully charged, the battery cell 7 is disassembled, and a vernier caliper is used to measure the size D4 of each electrode assembly 10 along the first direction X in the fully charged state.
  • the value of D2 is equal to D4.
  • the value of D2 is equal to the sum of the dimensions D4 of the multiple electrode assemblies 10 along the first direction X.
  • the dimensions D4 of different electrode assemblies 10 along the first direction X may be the same or different.
  • N is a positive integer greater than 0, that is to say, there may be one buffer member 30 or multiple buffer members 30 .
  • N buffer members 30 and M electrode assemblies 10 are stacked along the first direction X.
  • the embodiment of the present application does not limit the order in which the buffer member 30 and the electrode assembly 10 are stacked along the first direction X.
  • a plurality of electrode assemblies 10 can be arranged sequentially along the first direction X to form an electrode unit, and the buffer member 30 can be arranged on one side of the electrode unit along the first direction X.
  • the buffer member 30 may also be provided between two adjacent electrode assemblies 10 .
  • buffer members 30 there are multiple buffer members 30 and one electrode assembly 10 .
  • a plurality of buffer members 30 can be arranged sequentially along the first direction X to form a buffer unit, and the electrode assembly 10 can be arranged on one side of the buffer unit along the first direction X.
  • the electrode assembly 10 may also be disposed between two adjacent buffer members 30 .
  • each buffer member 30 may be adjacent to the electrode assembly 10 or may be adjacent to another buffer member 30 .
  • the buffer member 30 can be compressed when being squeezed by the electrode assembly 10 to provide space for expansion of the electrode assembly 10 and reduce the force between the first side wall 211 and the electrode assembly 10 .
  • the buffer member 30 has a certain elastic deformation ability. When the electrode assembly 10 is fully charged, the buffer member 30 can be compressed by the electrode assembly 10 . When the electrode assembly 10 is fully charged, the buffer member 30 can recover at least part of its deformation. It is ensured that the buffer member 30 can offset the electrode assembly 10, improve the uniformity of force distribution of the electrode assembly 10, and reduce the risk of wrinkles on the pole pieces of the electrode assembly 10.
  • the embodiment of the present application does not limit the specific material of the buffer member 30. It must have a certain ability to generate deformation and be able to recover at least part of the deformation when external force is removed. For example, when it is necessary to measure the size of each buffer member 30 in the uncompressed state along the first direction Dimension D5 along the first direction X in the uncompressed state. replaceable Specifically, during the preparation process of the battery cell 7, the dimension D5 of the buffer member 30 in the uncompressed state along the first direction X may be measured before the buffer member 30 is put into the case.
  • the value of D3 is equal to the value of D5.
  • the value of D3 is equal to the sum of the dimensions D5 of the multiple buffer members 30 along the first direction X.
  • the dimensions D5 of different buffer members 30 along the first direction X in the uncompressed state may be the same or different.
  • the embodiment of the present application does not limit the shape of the buffer member 30, and it may be in a plate shape, a block shape, or other irregular shapes.
  • the buffer member 30 can limit the deformation of the electrode assembly 10 to a certain extent when the battery cell 7 is first charged, improve the uniformity of the force distribution of the electrode assembly 10, reduce the risk of wrinkles on the pole pieces of the electrode assembly 10, and extend the length of the electrode assembly 10 life span.
  • the buffer member 30 is compressed when being squeezed by the electrode assembly 10 to provide space for the expansion of the electrode assembly 10 , reduce the force between the casing 20 and the electrode assembly 10 , and improve the electrode assembly. 10 cycle performance.
  • the buffer 30 can limit the deformation of the electrode assembly 10 to a certain extent when the battery cell 7 is first charged, if the value of (D2+D3)/D1 is too small, the buffer 30 may not be able to effectively limit the pole piece. of folds. In view of this, the inventor made (D2+D3)/D1 greater than or equal to 0.9 to improve space utilization and effectively reduce the risk of wrinkles in the pole piece.
  • the greater the value of (D2+D3)/D1 the greater the space and weight occupied by the buffer member 30, and the greater the compression amount of the buffer member 30 during the cycle of the battery cell 7.
  • the compressibility of the buffer member 30 after being inserted into the shell may be small, resulting in insufficient expansion that the buffer member 30 can absorb, resulting in excessive expansion force of the electrode assembly 10 .
  • the value of (D2+D3)/D1 may be 0.9, 0.95, 0.98, 1, 1.1, 1.2, 1.25, 1.3, 1.4 or 1.5.
  • D1, D2 and D3 satisfy: 0.98 ⁇ (D2+D3)/D1 ⁇ 1.25.
  • the electrode assembly 10 includes a main body 14 and first and second tabs 15 and 16 extending from the main body 14 .
  • the main body part 14 includes a positive electrode coating area, a positive electrode active material layer, a negative electrode coating area, a negative electrode active material layer, and a separator 13 .
  • One of the first tab 15 and the second tab 16 is a positive tab, and the other is a negative tab.
  • the size of the main body 14 along the first direction X is D4.
  • the housing 20 includes a housing 21 having an opening and an end cap 22 covering the opening.
  • the housing 21 includes two first side walls 211 .
  • the housing 21 may have a structure with an opening on one side, and the end cover 22 is provided as one and covers the opening of the housing 21 .
  • the housing 21 may also have a structure with openings on both sides, and two end caps 22 are provided, and the two end caps 22 cover the two openings of the housing 21 respectively.
  • the end cap 22 is connected to the housing 21 by welding, bonding, snapping or other means.
  • the first side wall 211 is a flat plate structure.
  • the housing 21 is provided with an opening at one end along the second direction Y.
  • the first direction X is perpendicular to the second direction Y.
  • the housing 21 includes two second side walls 212 , and the two second side walls 212 are oppositely arranged along the third direction Z.
  • the third direction Z is perpendicular to the first direction X and the second direction Y.
  • the two first side walls 211 and the two second side walls 212 are alternately arranged along the circumferential direction of the opening. Both ends of the first side wall 211 along the third direction Z are connected to the two second side walls 212 respectively.
  • first side walls 211 and second side walls 212 are connected by arcuate walls.
  • the first side wall 211 may be deformed due to expansion of the electrode assembly 10 . Since the deformation at the end of the first side wall 211 close to the second side wall 212 is small, the vernier caliper can clamp the ends of the two first side walls 211 close to the second side wall 212 and will measure The value is as D6.
  • the battery cell 7 further includes two electrode terminals 40 , and the two electrode terminals 40 may be disposed on the end cap 22 .
  • One electrode terminal 40 is used for electrical connection with the first pole piece 11 of the electrode assembly 10
  • the other electrode terminal 40 is used for electrical connection with the second pole piece 12 to lead the electric energy generated by the electrode assembly 10 to the outside of the housing 20 .
  • the cushioning member 30 may be a porous structure.
  • the micropores in the buffer member 30 can be used to store electrolyte. When the electrode assembly 10 expands and squeezes the buffer member 30, the electrolyte in the buffer member 30 can be squeezed out.
  • the cushioning member 30 may be made of foam.
  • the first direction X is parallel to the thickness direction of the battery cell 7 .
  • a plurality of battery cells 7 may be stacked along the first direction X.
  • D2 and D3 satisfy: D3 ⁇ 0.25 ⁇ D2.
  • the greater the value of D3 the greater the volume and weight of the buffer member 30, and the lower the gravimetric energy density of the battery cell 7.
  • the inventor found that when the value of D3 exceeds a certain range, the effect of the buffer 30 on improving the cycle performance of the electrode assembly 10 will not be further improved as D3 increases; after experiments, the inventor limited the value of D3 to less than Or equal to 0.25 ⁇ D2, the amount of buffer member 30 can be reduced, the energy density of battery cell 7 can be increased, and the cycle performance of electrode assembly 10 can be improved.
  • the buffer member 30 is a flat plate structure.
  • the flat plate structure is easy to form and can improve the uniformity of force distribution of the electrode assembly 10 when the electrode assembly 10 expands.
  • the buffer member 30 may be rectangular, circular, oval or otherwise formed.
  • the buffer member 30 is a rectangular flat plate.
  • bumper 30 is attached to electrode assembly 10 .
  • Attachment means that the buffer member 30 is attached to and connected to the surface of the electrode assembly 10 .
  • the buffer member 30 may be bonded to the electrode assembly 10 through an adhesive.
  • the buffer member 30 attached to the electrode assembly 10 can be installed into the housing 21 together with the electrode assembly 10 to simplify the assembly process.
  • the electrode assembly 10 can also limit the shaking of the buffer member 30 when the battery cell 7 is subjected to an external impact, so as to reduce the risk of the buffer member 30 being deflected.
  • the compression ratio f of the buffer member 30 under a pressure of 2 MPa satisfies: 1% ⁇ f ⁇ 99%.
  • the compression ratio f of the buffer member 30 under a pressure of 2 MPa satisfies: 40% ⁇ f ⁇ 99%.
  • the electrode assembly 10 includes a straight area 10a and two bending areas 10b.
  • the two bending areas 10b are respectively located on both sides of the straight area 10a along the third direction Z.
  • the third direction Z is perpendicular to the third direction Z.
  • the size of the buffer member 30 in the third direction Z is L1
  • the size of the electrode assembly 10 in the fully charged state along the third direction Z is L2
  • the size of one electrode assembly 10 in the first direction X in the fully charged state is D4.
  • L1, L2 and D4 satisfy: L1 ⁇ 0.85(L2-D4).
  • the straight region 10a is a region of the electrode assembly 10 that has a straight structure, and the portion of the pole piece located in the straight region 10a is generally in a straight state.
  • the bending area 10b is an area with a bending structure of the electrode assembly 10, and the portion of the pole piece located in the bending area 10b is generally in a bent state.
  • the portion of the pole piece located in the bending area 10b is generally bent into an arc shape.
  • the size of the bending area 10b along the third direction Z is approximately equal to half of D4, and L2-D4 is approximately the size of the straight area 10a along the third direction Z.
  • both ends of the buffer member 30 exceed the flat area 10a.
  • the buffer member 30 can effectively absorb the expansion of the flat area 10a and improve the cycle performance of the flat area 10a.
  • L1 and L2 satisfy: L1 ⁇ 1.1 ⁇ L2.
  • the portion of the buffer 30 that exceeds the electrode assembly 10 will not absorb the expansion of the electrode assembly 10 , but will instead increase the volume and weight of the buffer 30 .
  • the value of L1 is less than or equal to 1.1 ⁇ L2, so as to reduce the amount of buffer member 30 and increase the energy density of battery cell 7 .
  • the area of the projection of the buffer member 30 on the inner surface of the first side wall 211 along the first direction ⁇ 0.95 ⁇ S2.
  • the inner surface of the first side wall 211 will squeeze the electrode assembly 10 when it expands to limit the expansion deformation of the electrode assembly 10 .
  • the housing 20 also needs to accommodate other functional components, so part of the inner surface of the first side wall 211 does not press the electrode assembly 10 .
  • S1 ⁇ 0.95 ⁇ S2 is used to reduce the overall usage of the buffer 30, provide more space for other components in the housing 20, and improve the energy density and service life of the battery cell 7.
  • the size of each buffer member 30 along the first direction X in an uncompressed state is D5, and D5 satisfies: 0.1 mm ⁇ D5 ⁇ 10 mm.
  • the value of D5 is 0.1mm, 0.5mm, 1mm, 2mm, 4mm, 5mm, 8mm or 10mm.
  • D5 is too small, then in order to meet the requirements, a larger number of buffers need to be provided in the battery cell 7 30.
  • the structure of the battery cell 7 is complex and the assembly efficiency is low. Therefore, the embodiment of the present application limits the value of D5 to be greater than or equal to 0.1 mm.
  • the embodiment of the present application limits the value of D5 to be less than or equal to 10 mm.
  • D5 satisfies: 0.5mm ⁇ D5 ⁇ 4mm.
  • Figure 7 is a schematic cross-sectional view of a battery cell provided by some embodiments of the present application
  • Figure 8 is a partial cross-sectional schematic view of the electrode assembly and buffer member of the battery cell provided by some embodiments of the present application.
  • the electrode assembly 10 includes a first pole piece 11
  • the first pole piece 11 includes a first body 111 and an electrode extending from one end of the first body 111 along the second direction Y.
  • the second direction Y is perpendicular to the first direction X.
  • the size of the buffer member 30 along the second direction Y is H1; the first body 111 is provided with a first active material layer 112, and the size of the first active material layer 112 along the second direction Y is H2.
  • H1 and H2 satisfy: H1 ⁇ 0.85 ⁇ H2.
  • the main reason for the expansion of the electrode assembly 10 is the expansion of the active material layer during the charging process.
  • the embodiment of the present application limits the value of H1 to be greater than or equal to 0.85 ⁇ H2, so that the expansion of more than 85% of the area of the first active material layer 112 in the second direction Y can be absorbed by the buffer 30 to reduce the first activity.
  • the pressure on the material layer 112 improves the cycle performance of the electrode assembly 10 .
  • the first pole piece 11 may be a positive pole piece or a negative pole piece.
  • the first pole piece 11 is a negative pole piece
  • the first active material layer 112 is a negative active material layer.
  • the first body 111 also includes a negative electrode coating region of the negative electrode current collector.
  • the first active material layer 112 includes a base region 112a and a thinned region 112b connected to the base region 112a.
  • the thickness of the thinned region 112b is smaller than the thickness of the base region 112a.
  • the thinned area 112b is located on a side of the base area 112a close to the first tab 15 .
  • both ends of the buffer member 30 exceed the base region 112a.
  • the first active material layer 112 needs to be rolled to increase the compaction density of the first active material layer 112 .
  • the embodiment of the present application reduces the thickness of the thinned area 112b to reduce the stress concentration at the interface between the first body 111 and the first tab 15 during the rolling process and reduce the risk of cracking of the first tab 15.
  • the expansion force generated when the base area 112a expands is greater. Therefore, in the embodiment of the present application, the two ends of the buffer member 30 along the second direction Y exceed the base area 112a to effectively absorb the expansion force of the base area 112a. Expansion improves the cycle performance of the electrode assembly 10 .
  • the electrode assembly 10 further includes a separator 13 , which is stacked with the first body 111 .
  • the size of the isolator 13 along the second direction Y is H3; H1 and H3 satisfy: H1 ⁇ 1.1 ⁇ H3.
  • the isolation member 13 is used to insulate and isolate the first body 111 from the second pole piece 12 .
  • the portion of the spacer 13 that exceeds the spacer 13 will not absorb the expansion of the electrode assembly 10 , but will increase the volume and weight of the buffer 30 .
  • the value of H1 is less than or equal to 1.1 ⁇ H3, so as to reduce the amount of buffer member 30 and increase the energy density of battery cell 7 .
  • both ends of the buffer member 30 do not exceed the isolation member 13 to reduce the amount of the buffer member 30, reduce the risk of the buffer member 30 interfering with other components, and improve the battery cell 7 energy density.
  • Figure 9 is a schematic structural diagram of a battery cell provided by other embodiments of the present application.
  • a buffer 30 is provided between at least two adjacent electrode assemblies 10 .
  • Disposing the buffer member 30 between two adjacent electrode assemblies 10 can reduce the risk of the buffer member 30 shaking when the battery cell 7 is subjected to an external impact.
  • FIG. 10 is a schematic structural diagram of a battery cell provided by some embodiments of the present application. As shown in FIG. 10 , in some embodiments, there are multiple electrode assemblies 10 and multiple buffer members 30 .
  • Two electrode assemblies 10 there are two electrode assemblies 10 and two buffer members 30 .
  • Two electrode assemblies 10 are arranged adjacently to form an electrode unit, and two buffer members 30 are respectively located on both sides of the electrode unit along the first direction X.
  • FIG. 11 is a schematic structural diagram of a battery cell provided in some embodiments of the present application. As shown in FIG. 11 , in some embodiments, there are four electrode assemblies 10 and two buffer members 30 . Four electrode assemblies 10 are arranged adjacently to form an electrode unit, and two buffer members 30 are respectively located on both sides of the electrode unit along the first direction X.
  • the present application also provides a battery, which includes a plurality of battery cells provided in any of the above embodiments.
  • the present application also provides an electrical device, which includes the battery cell provided in any of the above embodiments, and the battery cell is used to provide electrical energy to the electrical device.
  • the battery cell 7 of the embodiment of the present application includes a housing 20 , two electrode assemblies 10 and two buffers 30 .
  • the housing 20 includes two first side walls 211 oppositely arranged along the first direction X, and the distance between the two first side walls 211 along the first direction X is D1.
  • the two electrode assemblies 10 are accommodated in the housing 20. In a fully charged state, the sum of the dimensions of the two electrode assemblies 10 along the first direction X is D2.
  • the two electrode assemblies 10 constitute an electrode unit, and the two buffer members 30 are respectively located on both sides of the electrode unit along the first direction X.
  • the buffer members 30 are configured to be compressible.
  • each buffer member 30 along the first direction X in an uncompressed state is D5.
  • the sum of the dimensions of the two buffer members 30 in the uncompressed state along the first direction X is D5. for D3.
  • D1, D2 and D3 satisfy: 0.9 ⁇ (D2+D3)/D1 ⁇ 1.5.
  • Figure 12 is a schematic flowchart of a method for manufacturing a battery cell according to some embodiments of the present application.
  • the embodiment of the present application provides a method for manufacturing a battery cell, which includes:
  • the shell includes two first side walls arranged oppositely along a first direction;
  • S200 provides electrode components and buffer parts
  • the distance between the two first side walls along the first direction is D1.
  • the number of electrode components is set to M, and M is a positive integer greater than 0.
  • the sum of the dimensions of the M electrode assemblies along the first direction is D2.
  • the buffer members are configured to be compressible, and the sum of the dimensions of the N buffer members in an uncompressed state along the first direction is D3.
  • D1, D2 and D3 satisfy: 0.9 ⁇ (D2+D3)/D1 ⁇ 1.5.
  • steps S100 and S200 are executed in no particular order and can also be executed at the same time.
  • Figure 13 is a schematic block diagram of a battery cell manufacturing system provided by some embodiments of the present application.
  • this embodiment of the present application provides a battery cell manufacturing system 90 , which includes a first providing device 91 , a second providing device 92 and an assembly device 93 .
  • the first providing device 91 is used to provide a housing, which includes two first side walls oppositely arranged along a first direction.
  • the second providing device 92 is used to provide the electrode assembly and the buffer member.
  • the assembly device 93 is used to install the electrode assembly and the buffer member into the housing.
  • the distance between the two first side walls along the first direction is D1.
  • the number of electrode components is set to M, and M is a positive integer greater than 0. In the fully charged state, the sum of the dimensions of the M electrode assemblies along the first direction is D2.
  • N buffer members There are N buffer members, and N is a positive integer greater than 0; the N buffer members and M electrode assemblies are stacked along the first direction.
  • the buffer members are configured to be compressible, and the sum of the dimensions of the N buffer members in an uncompressed state along the first direction is D3.
  • D1, D2 and D3 satisfy: 0.9 ⁇ (D2+D3)/D1 ⁇ 1.5.
  • Embodiment 1 can be prepared according to the following steps:
  • step (VI) as shown in FIG. 14 , two buffer members 30 and two electrode assemblies 10 are stacked along the first direction X, and the housing 21 includes two first side walls 211 oppositely arranged along the first direction X. .
  • the distance D1 between the two first side walls 211 along the first direction X was measured to be 27 mm.
  • the thickness D5 of the buffer member 30 measured using a vernier caliper is 0.45 mm; correspondingly, the sum of the dimensions of the two buffer members 30 along the first direction X in the compressed state is D3, and D3 is 0.9 mm.
  • Two battery cells 7 were prepared according to the above preparation steps, and interface testing and cycle performance testing were performed respectively.
  • a battery cell 7 In a normal temperature environment, a battery cell 7 is charged at a rate of 0.33C until it is fully charged. After the battery cell 7 is fully charged, the battery cell 7 is disassembled, and a vernier caliper is used to measure the size of each electrode assembly 10 along the first direction X in the fully charged state. After completing the dimensional measurement, the electrode assembly 10 is further disassembled, and the interface state of the negative electrode piece is observed.
  • the sum D2 of the dimensions of the two electrode assemblies 10 along the first direction X is 25.6 mm.
  • the clamp clamps the two first side walls 211 of the battery cell 7 from both sides and applies a clamping force of 3000N to the first side walls 211 .
  • the clamp is provided with a pressure sensor to detect the pressure F between the first side wall 211 and the clamp in real time.
  • the battery cell 7 In a normal temperature environment, the battery cell 7 is charged at a rate of 1C, discharged at a rate of 1C, and a full-charge-discharge cycle test is performed until the capacity of the battery cell 7 decreases to 90% of the initial capacity.
  • the status of the battery cell 7 is monitored in real time.
  • the clamp includes two clamping plates, which clamp the battery cell 7 from both sides and face the two first side walls 211 respectively.
  • a buffer pad may be provided between the clamping plates and the corresponding first side walls 211 .
  • Example 2 The preparation method and detection method of the battery cell in Example 2 are as in Example 1, except that D3 is 1.4mm.
  • Example 3 The preparation method and detection method of the battery cell in Example 3 are as in Example 1, except that D3 is 4.1 mm.
  • Example 4 The preparation method and detection method of the battery cell in Example 4 are as in Example 1, except that D3 is 8.15mm.
  • Example 5 The preparation method and detection method of the battery cell in Example 5 are as in Example 1, except that D3 is 12.2mm.
  • Example 6 The preparation method and detection method of the battery cell in Example 6 are as in Example 1, except that D3 is 14.9mm.
  • Example 7 The preparation method and detection method of the battery cell in Example 7 are as in Example 1, except that D3 is 0.7mm and D2 is 23.6mm.
  • Example 8 The preparation method and detection method of the battery cell in Example 8 are as in Example 1, except that D3 is 2.1mm and D2 is 23.6mm.
  • Comparative Example 1 The preparation method and detection method of the battery cell in Comparative Example 1 are as in Example 1. The difference is that D2 is 24.3mm, and there is no buffer inside Comparative Example 1 (that is, D3 is 0).
  • Comparative Example 2 The preparation method and detection method of the battery cell in Comparative Example 1 are as in Example 1. The difference is that D2 is 25.6mm, and there is no buffer inside Comparative Example 1 (that is, D3 is 0).
  • Comparative Example 3 The preparation method and detection method of the battery cell of Comparative Example 1 are as in Example 1. The difference is that D2 is 26.4mm, and there is no buffer inside Comparative Example 1 (that is, D3 is 0).
  • Comparative Example 4 The preparation method and detection method of the battery cell in Comparative Example 4 are as in Example 1, except that D3 is 0.6mm and D2 is 21mm.
  • Comparative Example 5 The preparation method and detection method of the battery cell in Comparative Example 5 are as in Example 1, except that D3 is 17.6mm.
  • the ratio of the size of the wrinkles to the size of the pole piece is less than 5%, it is regarded as having no wrinkles, and the ratio of the size of the wrinkles to the size of the pole piece is 5%-30%. It is considered as a slight wrinkle. If the ratio of the size of the wrinkle to the size of the pole piece is greater than 30%, it is considered as a serious wrinkle.
  • the embodiments of the present application can reduce the risk of wrinkles in the pole pieces when the battery cells are first charged and reduce the expansion of the battery cells during the cycle by providing buffer members. force, extending the number of cycles of battery cells and improving the cycle performance of battery cells.
  • the examples of this application limit the value of (D2+D3)/D1 to 0.9- Between 1.5 and 1.5, it can reduce the risk of wrinkles in the pole piece when the battery cell is first charged, reduce the expansion force of the battery cell during the cycle, extend the number of cycles of the battery cell, and improve the cycle performance of the battery cell. .

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Abstract

本申请公开了一种电池单体、电池以及用电装置。电池单体包括外壳、电极组件和缓冲件。外壳包括沿第一方向相对设置的两个第一侧壁，两个第一侧壁沿第一方向的间距为D1。电极组件容纳于外壳内。电极组件设置为M个，M为大于0的正整数。在满充状态下，M个电极组件沿第一方向的尺寸之和为D2。缓冲件容纳于外壳内。缓冲件设置为N个，N为大于0的正整数。N个缓冲件与M个电极组件沿第一方向层叠。缓冲件被配置为可压缩地，N个缓冲件在未压缩的状态下沿第一方向的尺寸之和为D3。D1、D2和D3满足：0.9≤(D2+D3)/D1≤1.5。本申请实施例可以改善电池单体的循环性能，并减小膨胀力的增长。

Description

电池单体、电池以及用电装置
相关申请的交叉引用
本申请要求享有于2022年04月12日提交的名称为“电池单体、电池以及用电装置”的中国专利申请202210379965.0的优先权，该申请的全部内容通过引用并入本文中。
技术领域
本申请涉及电池领域，特别是涉及一种电池单体、电池以及用电装置。
背景技术
电池单体广泛用于电子设备，例如手机、笔记本电脑、电瓶车、电动汽车、电动飞机、电动轮船、电动玩具汽车、电动玩具轮船、电动玩具飞机和电动工具等等。电池单体可以包括镉镍电池单体、氢镍电池单体、锂离子电池单体和二次碱性锌锰电池单体等。
在电池技术的发展中，如何改善电池单体的循环性能，是电池技术中一个重要的研究方向。
发明内容
本申请提供一种电池单体及其制造方法和制造系统、电池以及用电装置，其能改善电池单体的循环性能。
第一方面，本申请提供一种电池单体，其包括外壳、电极组件和缓冲件。外壳包括沿第一方向相对设置的两个第一侧壁，两个第一侧壁沿第一方向的间距为D1。电极组件容纳于外壳内。电极组件设置为M个，M为大于0的正整数。在满充状态下，M个电极组件沿第一方向的尺寸之和为D2。缓冲件容纳于外壳内。缓冲件设置为N个，N为大于0的正整数。N个缓冲件与M个电极组件沿第一方向层叠。缓冲件被配置为可压缩地，N个缓冲件在未压缩的状态下沿第一方向的尺寸之和为D3。D1、D2和D3满足：0.9≤(D2+D3)/D1≤1.5。
在上述技术方案中，缓冲件可以在电池单体初次充电时在一定程度上限制电极组件的变形，改善电极组件受力分布的均匀性，降低电极组件的极片出现褶皱的风险，延长电极组件的寿命。在电池单体的循环过程中，缓冲件在受到电极组件的挤压时压缩，以为电极组件的膨胀提供空间，减小外壳与电极组件之间的作用力，改善电极组件的循环性能。上述技术方案将(D2+D3)/D1的值限定在0.9-1.5，可以降低极片出现褶皱的风险，节省缓冲件的用量，提高电池单体的能量密度，减小电极组件的膨胀力，改善电极组件的循环性能。
在一些实施方式中，D1、D2和D3满足：0.98≤(D2+D3)/D1≤1.25。
在一些实施方式中，第一方向平行于电池单体的厚度方向。
在一些实施方式中，D2和D3满足：D3≤0.25·D2。上述技术方案可以减小缓冲件的用量，提高电池单体的能量密度，并改善电极组件的循环性能。
在一些实施方式中，电极组件包括第一极片，第一极片包括第一主体和从第一主体沿第二方向的一端引出的第一极耳，第二方向垂直于第一方向。缓冲件沿第二方向的尺寸为H1；第一主体设有第一活性物质层，第一活性物质层沿第二方向的尺寸为H2。H1、H2满足：H1≥0.85·H2。
电极组件膨胀的主要原因是活性物质层在充电过程中的膨胀。上述技术方案将H1的值限定为大于或等于0.85·H2，使第一活性物质层在第二方向上85％以上的区域的膨胀能够被缓冲件吸收，以减小第一活性物质层受到的压力，改善电极组件的循环性能。
在一些实施方式中，第一活性物质层包括基体区和连接于基体区的削薄区，削薄区的厚度小于基体区的厚度。在第二方向上，削薄区位于基体区的靠近第一极耳的一侧。在第二方向上，缓冲件的两端均超出基体区。
相对于削薄区，基体区膨胀时产生的膨胀力更大，因此，上述技术方案使缓冲件沿第二方向的两端超出基体区，以有效地吸收基体区的膨胀，改善电极组件的循环性能。
在一些实施方式中，电极组件还包括隔离件，隔离件与第一主体层叠设置。隔离件沿第二方向的尺寸为H3。H1、H3满足：H1≤1.1·H3。在第二方向上，隔离件超出隔离件的部分不会吸收电极组件的膨胀，反而会增大缓冲件的体积和重量。上述技术方案使H1的值小于或等于1.1·H3，以减少缓冲件的用量，提高电池单体的能量密度。
在一些实施方式中，在第二方向上，缓冲件的两端均不超出隔离件，以减少缓冲件的用量，降低缓冲件与其它构件干涉的风险，提高电池单体的能量密度。
在一些实施方式中，电极组件包括平直区和两个弯折区，两个弯折区分别位于平直区沿第三方向的两侧，第三方向垂直于第一方向。缓冲件在第三方向上的尺寸为L1，电极组件在满充状态下沿第三方向的尺寸为L2，一个电极组件在满充状态下沿第一方向的尺寸为D4。L1、L2和D4满足：L1≥0.85(L2-D4)。
由于电极组件的弯折区与第一侧壁之间的间隙较大，所以弯折区产生的膨胀力较小。电极组件的平直区与第一侧壁之间的间隙较小，所以平直区产生的膨胀力较大。上述技术方案将L1的值限定为大于或等于0.85(L2-D4)，使平直区在第三方向上的85％以上的区域的膨胀能够被缓冲件吸收，以保证平直区的循环性能。
在一些实施方式中，在第三方向上，缓冲件的两端超出平直区。缓冲件可以有效地吸收平直区的膨胀，改善平直区的循环性能。
在一些实施方式中，L1和L2满足：L1≤1.1·L2。在第三方向上，缓冲件超过电极组件的部分不会吸收电极组件的膨胀，反而会增大缓冲件的体积和重量。本实施例使L1的值小于或等于1.1·L2，以减少缓冲件的用量，提高电池单体的能量密度。
在一些实施方式中，缓冲件沿第一方向在第一侧壁的内表面上的投影的面积为S1，第一侧壁的内表面的面积为S2，S1和S2满足：S1≤0.95·S2。
上述技术方案可减小缓冲件的整体使用量，为外壳内的其它构件提供更多的空间，提高电池单体的能量密度和使用寿命。
在一些实施方式中，各缓冲件在未压缩的状态下沿第一方向的尺寸为D5，D5满足：0.1mm≤D5≤10mm。
在一些实施方式中，缓冲件在2Mpa的压力下的压缩率f满足：1％≤f≤99％。
在一些实施方式中，缓冲件附接于电极组件。附接于电极组件的缓冲件可以和电极组件一同装入壳体内，以简化装配工艺。电极组件还能够在电池单体受到外部冲击时限制缓冲件的晃动，以降低缓冲件偏移的风险。
在一些实施方式中，电极组件为多个。至少相邻的两个电极组件之间设有缓冲件。将缓冲件设置在相邻的两个电极组件之间，可以在电池单体受到外部冲击时降低缓冲件晃动的风险。
在一些实施方式中，缓冲件为平板结构。平板结构易于成型，且能够在电极组件膨胀时改善电极组件受力分布的均一性。
第二方面，本申请实施例提供了一种电池，其包括多个第一方面任一实施方式的电池单体。
第三方面，本申请实施例提供了一种用电装置，其包括第一方面任一实施方式的电池单体，电池单体用于提供电能。
第四方面，本申请实施例提供了一种电池单体的制造方法，其包括：提供外壳，外壳包括沿第一方向相对设置的两个第一侧壁；提供电极组件和缓冲件；将电极组件和缓冲件安装到外壳内。两个第一侧壁沿第一方向的间距为D1。电极组件设置为M个，M为大于0的正整数；在满充状态下，M个电极组件沿第一方向的尺寸之和为D2。缓冲件为N个，N为大于0的正整数；N个缓冲件与M个电极组件沿第一方向层叠；缓冲件被配置为可压缩地，N个缓冲件在未压缩的状态下沿第一方向的尺寸之和为D3。D1、D2和D3满足：0.9≤(D2+D3)/D1≤1.5。
第五方面，本申请实施例提供了一种电池单体的制造系统，其包括第一提供装置、第二提供装置和组装装置。第一提供装置用于提供外壳，外壳包括沿第一方向相对设置的两个第一侧壁。第二提供装置用于提供电极组件和缓冲件。组装装置用于将电极组件和缓冲件安装到外壳内。两个第一侧壁沿第一方向的间距为D1。电极组件设置为M个，M为大于0的正整数；在满充状态下，M个电极组件沿第一方向的尺寸之和为D2。缓冲件为N个，N为大于0的正整数；N个缓冲件与M个电极组件沿第一方向层叠；缓冲件被配置为可压缩地，N个缓冲件在未压缩的状态下沿第一方向的尺寸之和为D3。D1、D2和D3满足：0.9≤(D2+D3)/D1≤1.5。
附图说明
下面将参考附图来描述本申请示例性实施例的特征、优点和技术效果。
图1为本申请一些实施例提供的车辆的结构示意图；
图2为本申请一些实施例提供的电池的爆炸示意图；
图3为图2所示的电池模块的爆炸示意图；
图4为本申请一些实施例提供的电池单体的爆炸示意图；
图5为本申请一些实施例提供的电池单体的结构示意图；
图6为本申请一些实施例提供的电池单体的电极组件的剖视示意图；
图7为本申请一些实施例提供的电池单体的剖视示意图；
图8为本申请一些实施例提供的电池单体的电极组件和缓冲件的局部剖视示意图；
图9为本申请另一些实施例提供的电池单体的结构示意图；
图10为本申请又一些实施例提供的电池单体的结构示意图；
图11为本申请再一些实施例提供的电池单体的结构示意图；
图12为本申请一些实施例提供的电池单体的制造方法的流程示意图；
图13为本申请一些实施例提供的电池单体的制造系统的示意性框图；
图14为本申请一些实施例提供的电池单体的结构示意图。
具体实施方式的附图标记如下：
1、车辆；2、电池；3、控制器；4、马达；5、箱体；5a、第一箱体部；5b、第二
箱体部；5c、容纳空间；6、电池模块；7、电池单体；
10、电极组件；11、第一极片；111、第一主体；112、第一活性物质层；112a、
基体区；112b、削薄区；12、第二极片；13、隔离件；14、主体部；15、第一极耳；16、第二极耳；10a、平直区；10b、弯折区；
20、外壳；21、壳体；211、第一侧壁；212、第二侧壁；22、端盖；
30、缓冲件；40、电极端子；
90、制造系统；91、第一提供装置；92、第二提供装置；93、组装装置；
X、第一方向；Y、第二方向；Z、第三方向。
具体实施方式
为使本申请实施例的目的、技术方案和优点更加清楚，下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
除非另有定义，本申请所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同；本申请中在申请的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申请；本申请的说明书和权利要求书及上述附图说明中的术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排他的包含。本申请的说明书和权利要求书或上述附图中的术语“第一”、“第二”等是用于区别不同对象，而不是用于描述特定顺序或主次关系。
在本申请中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。
在本申请的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”、“附接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
本申请中术语“和/或”，仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本申请中字符“/”，一般表示前后关联对象是一种“或”的关系。
在本申请的实施例中，相同的附图标记表示相同的部件，并且为了简洁，在不同实施例中，省略对相同部件的详细说明。应理解，附图示出的本申请实施例中的各种部件的厚度、长宽等尺寸，以及集成装置的整体厚度、长宽等尺寸仅为示例性说明，而不应对本申请构成任何限定。
本申请中出现的“多个”指的是两个以上(包括两个)。
本申请中，电池单体可以包括锂离子二次电池单体、锂离子一次电池单体、锂硫电池单体、钠锂离子电池单体、钠离子电池单体或镁离子电池单体等，本申请实施例对此并不限定。电池单体可呈圆柱体、扁平体、长方体或其它形状等，本申请实施例对此也不限定。
本申请的实施例所提到的电池是指包括一个或多个电池单体以提供更高的电压和容量的单一的物理模块。例如，本申请中所提到的电池可以包括电池模块或电池包等。电池一般包括用于封装一个或多个电池单体的箱体。箱体可以避免液体或其他异物影响电池单体的充电或放电。
电池单体包括电极组件和电解液，电极组件包括正极极片、负极极片和隔离件。电池单体主要依靠金属离子在正极极片和负极极片之间移动来工作。正极极片包括正极集流体和正极活性物质层，正极活性物质层涂覆于正极集流体的表面；正极集流体包括正极涂覆区和连接于正极涂覆区的正极极耳，正极涂覆区涂覆有正极活性物质层，正极极耳未涂覆正极活性物质层。以锂离子电池单体为例，正极集流体的材料可以为铝，正极活性物质层包括正极活性物质，正极活性物质可以为钴酸锂、磷酸铁锂、三元锂或锰酸锂等。负极极片包括负极集流体和负极活性物质层，负极活性物质层涂覆于负极集流体的表面；负极集流体包括负极涂覆区和连接于负极涂覆区的负极极耳，负极涂覆区涂覆有负极活性物质层，负极极耳未涂覆负极活性物质层。负极集流体的材料可以为铜，负极活性物质层包括负极活性物质，负极活性物质可以为碳或硅等。隔离件的材质可以为PP(polypropylene，聚丙烯)或PE(polyethylene，聚乙烯)等。
电池单体还包括外壳，外壳内部形成用于容纳电极组件的容纳腔。外壳可以从外侧保护电极组件，以避免外部的异物影响电极组件的充电或放电。
在充电的过程中，电极组件会出现膨胀；膨胀的电极组件会挤压外壳，对应地，外壳对电极组件施加反作用力，以限制电极组件的膨胀。如果电极组件与外壳之间的作用力过大，那么极片之间的电解液可能会被压出，影响电极组件的循环性能。
发明人尝试在电极组件与外壳之间设置间隙，该间隙可以为电极组件的膨胀预留空间，进而减小外壳与电极组件之间的作用力，改善电极组件的循环性能。然而，发明人发现，在电极组件初次充电时，由于该间隙的存在，电极组件不受外壳束缚或受到外壳的束缚力较小，造成电极组件受力均一性较差，引发极片褶皱的风险。如果极片出现褶皱，那么在后续的循环过程中，极片可能会出现金属离子析出的情况，降低电极组件的循环寿命，甚至会造成电极组件失效。
鉴于此，发明人在外壳内设置缓冲件，缓冲件可以在电池单体初次充电时在一定程度上限制电极组件的变形，改善电极组件受力分布的均匀性，降低电极组件的极片出现褶皱的风险，延长电极组件的寿命。在电池单体的循环过程中，缓冲件在受到电极组件的挤压时压缩，以为电极组件的膨胀提供空间，减小外壳与电极组件之间的作用力，改善电极组件的循环性能。发明人经过计算和试验，根据电极组件的尺寸和外壳的尺寸来设置缓冲件的尺寸，以改善电极组件的循环性能。
本申请实施例描述的电池单体适用于电池以及使用电池单体的用电装置。
用电装置可以是车辆、手机、便携式设备、笔记本电脑、轮船、航天器、电动玩具和电动工具等等。车辆可以是燃油汽车、燃气汽车或新能源汽车，新能源汽车可以是纯电动汽车、混合动力汽车或增程式汽车等；航天器包括飞机、火箭、航天飞机和宇宙飞船等等；电动玩具包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等；电动工具包括金属切削电动工具、研磨电动工具、装配电动工具和铁道用电动工具，例如，电钻、电动砂轮机、电动扳手、电动螺丝刀、电锤、冲击电钻、混凝土振动器和电刨等等。本申请实施例对上述用电装置不做特殊限制。
以下实施例为了方便说明，以用电装置为车辆为例进行说明。
图1为本申请一些实施例提供的车辆的结构示意图。
如图1所示，车辆1的内部设置有电池2，电池2可以设置在车辆1的底部或头部或尾部。电池2可以用于车辆1的供电，例如，电池2可以作为车辆1的操作电源。
车辆1还可以包括控制器3和马达4，控制器3用来控制电池2为马达4供电，例如，用于车辆1的启动、导航和行驶时的工作用电需求。
在本申请一些实施例中，电池2不仅仅可以作为车辆1的操作电源，还可以作为车辆1的驱动电源，代替或部分地代替燃油或天然气为车辆1提供驱动动力。
图2为本申请一些实施例提供的电池的爆炸示意图。
如图2所示，电池2包括箱体5和电池单体(未示出)，电池单体容纳于箱体5内。
箱体5用于容纳电池单体，箱体5可以是多种结构。在一些实施例中，箱体5可以包括第一箱体部5a和第二箱体部5b，第一箱体部5a与第二箱体部5b相互盖合，第一箱体部5a和第二箱体部5b共同限定出用于容纳电池单体的容纳空间5c。第二箱体部5b可以是一端开口的空心结构，第一箱体部5a为板状结构，第一箱体部5a盖合于第二箱体部5b的开口侧，以形成具有容纳空间5c的箱体5；第一箱体部5a和第二 箱体部5b也均可以是一侧开口的空心结构，第一箱体部5a的开口侧盖合于第二箱体部5b的开口侧，以形成具有容纳空间5c的箱体5。当然，第一箱体部5a和第二箱体部5b可以是多种形状，比如，圆柱体、长方体等。
为提高第一箱体部5a与第二箱体部5b连接后的密封性，第一箱体部5a与第二箱体部5b之间也可以设置密封件，比如，密封胶、密封圈等。
假设第一箱体部5a盖合于第二箱体部5b的顶部，第一箱体部5a亦可称之为上箱盖，第二箱体部5b亦可称之为下箱体。
在电池2中，电池单体可以是一个，也可以是多个。若电池单体为多个，多个电池单体之间可串联或并联或混联，混联是指多个电池单体中既有串联又有并联。多个电池单体之间可直接串联或并联或混联在一起，再将多个电池单体构成的整体容纳于箱体5内；当然，也可以是多个电池单体先串联或并联或混联组成电池模块6，多个电池模块6再串联或并联或混联形成一个整体，并容纳于箱体5内。
图3为图2所示的电池模块的爆炸示意图。
在一些实施例中，如图3所示，电池单体7为多个，多个电池单体7先串联或并联或混联组成电池模块6。多个电池模块6再串联或并联或混联形成一个整体，并容纳于箱体内。
电池模块6中的多个电池单体7之间可通过汇流部件实现电连接，以实现电池模块6中的多个电池单体7的并联或串联或混联。
图4为本申请一些实施例提供的电池单体的爆炸示意图；图5为本申请一些实施例提供的电池单体的结构示意图，其中端盖省略；图6为本申请一些实施例提供的电池单体的电极组件的剖视示意图。
如图4至图6所示，本申请实施例的电池单体7包括外壳20、电极组件10和缓冲件30。外壳20包括沿第一方向X相对设置的两个第一侧壁211，两个第一侧壁211沿第一方向X的间距为D1。电极组件10设置为M个，M个电极组件10容纳于外壳20内，在满充状态下，M个电极组件10沿第一方向X的尺寸之和为D2，M为大于0的正整数。缓冲件30设置为N个，N个缓冲件30容纳于外壳20内，并与M个电极组件10沿第一方向X层叠。缓冲件30被配置为可压缩地，N个缓冲件30在未压缩的状态下沿第一方向X的尺寸之和为D3，N为大于0的正整数。D1、D2和D3满足：0.9≤(D2+D3)/D1≤1.5。
外壳20为空心结构，其内部形成用于容纳电极组件10和电解液的容纳腔。外壳20可以是多种形状，比如长方体等。外壳20的形状可根据电极组件10的具体形状来确定，比如，若电极组件10为长方体结构，则可选用长方体外壳。
本实施例对外壳20的材质不作限定。例如，外壳20可以是由铝、钢、塑料等硬质材料制成的外壳20，也可以是由铝塑膜、钢塑膜或其它软质材料制成的外壳20。
两个第一侧壁211分别位于容纳腔沿第一方向X的两侧。示例性地，容纳腔沿第一方向X的尺寸为D1。
D1的值可通过多种方式测出，例如，D1的值可使用游标卡尺测量，或采用机械断面/表面分析等显微标点测量。
电极组件10包括第一极片11和第二极片12，电极组件10主要依靠金属离子在第一极片11和第二极片12之间移动来工作。示例性地，电极组件10还包括隔离件13，隔离件13用于将第一极片11和第二极片12绝缘隔离。
第一极片11的极性和第二极片12的极性相反。具体地。第一极片11和第二极片12中的一者为正极极片，另一者为负极极片。
M为大于0的正整数，也就是说，电极组件10可以是一个，也可以是多个。当电极组件10为多个时，多个电极组件10可以沿第一方向X层叠设置。
在满充状态下，电极组件10会出现膨胀。示例性地，在电池单体7制备完成后，在常温环境下，对电池单体7以0.33C倍率充电，直至满充。电池单体7满充后，对电池单体7进行拆解，并使用游标卡尺测出各电极组件10在满充状态下沿第一方向X的尺寸D4。
当电池单体7的内部仅设置一个电极组件10时，D2的值等于D4。当电池单体7的内部设置多个电极组件10时，D2的值等于多个电极组件10沿第一方向X的尺寸D4之和。
当电极组件10设置为多个时，不同的电极组件10沿第一方向X的尺寸D4可以相同，也可以不同。
N为大于0的正整数，也就是说，缓冲件30可以是一个，也可以是多个。
N个缓冲件30与M个电极组件10沿第一方向X层叠。本申请实施例不限制缓冲件30和电极组件10沿第一方向X层叠的顺序。
在一些示例中，缓冲件30为一个，电极组件10为多个。多个电极组件10可以沿第一方向X依次设置并构成一个电极单元，缓冲件30可设置于电极单元沿第一方向X的一侧。可替代地，缓冲件30也可以设置在相邻的两个电极组件10之间。
在另一些示例中，缓冲件30为多个，电极组件10为一个。多个缓冲件30可以沿第一方向X依次设置并构成一个缓冲单元，电极组件10可设置于缓冲单元沿第一方向X的一侧。可替代地，电极组件10也可以设置在相邻的两个缓冲件30之间。
在又一些示例中，缓冲件30为多个，电极组件10为多个。多个缓冲件30和多个电极组件10沿第一方向X层叠的顺序可以根据需求自由设定。例如，各缓冲件30可以与电极组件10相邻，也可以与另一个缓冲件30相邻。
缓冲件30在受到电极组件10的挤压时可被压缩，以为电极组件10的膨胀提供空间，减小第一侧壁211与电极组件10之间的作用力。
示例性地，缓冲件30具有一定的弹性变形能力，在电极组件10满充时，缓冲件30可被电极组件10压缩，在电极组件10满放时，缓冲件30可以恢复至少部分形变，以保证缓冲件30能够与电极组件10相抵，改善电极组件10受力分布的均匀性，降低电极组件10的极片出现褶皱的风险。
本申请实施例对缓冲件30的具体材料不作限制，其需要具有一定的产生形变的能力，并能够在外力去除时恢复至少部分形变。示例性地，当需要测量各缓冲件30在未压缩的状态下沿第一方向X的尺寸时，可以拆解电池单体7并将缓冲件30取出，然后使用游标卡尺测出各缓冲件30在未压缩的状态下沿第一方向X的尺寸D5。可替代 地，在电池单体7的制备过程中，缓冲件30在未压缩的状态下沿第一方向X的尺寸D5可以在缓冲件30入壳之前测量。
当电池单体7的内部仅设置一个缓冲件30时，D3的值等于D5的值。电池单体7的内部设置多个缓冲件30时，D3的值等于多个缓冲件30沿第一方向X的尺寸D5之和。
当缓冲件30设置为多个时，不同的缓冲件30在未压缩的状态下沿第一方向X的尺寸D5可以相同，也可以不同。
本申请实施例对缓冲件30的形状不作限制，其可以呈板状、块状或其它不规则形状。
缓冲件30可以在电池单体7初次充电时在一定程度上限制电极组件10的变形，改善电极组件10受力分布的均匀性，降低电极组件10的极片出现褶皱的风险，延长电极组件10的寿命。在电池单体7的循环过程中，缓冲件30在受到电极组件10的挤压时压缩，以为电极组件10的膨胀提供空间，减小外壳20与电极组件10之间的作用力，改善电极组件10的循环性能。
(D2+D3)/D1的值越小，外壳20内部空间的利用率越低，电极组件10在充电过程中受到来自第一侧壁211的束缚力越小，电极组件10的极片出现褶皱的风险越高。虽然缓冲件30可以在电池单体7初次充电时在一定程度上限制电极组件10的变形，但是，如果(D2+D3)/D1的值过小，那么缓冲件30可能难以有效地限制极片的褶皱。鉴于此，发明人使(D2+D3)/D1大于或等于0.9，以提高空间利用率，并有效地降低极片出现褶皱的风险。
(D2+D3)/D1的值越大，缓冲件30可以在电池单体7初次充电时可更好地限制电极组件10的变形。当然，(D2+D3)/D1的值越大，缓冲件30占用的空间和重量越大，且缓冲件30在电池单体7的循环过程中的压缩量越大。如果(D2+D3)/D1的值过大，可能会造成缓冲件30在入壳后的可压缩量偏小，导致缓冲件30可吸收的膨胀量不足，造成电极组件10的膨胀力过大。鉴于此，发明人使(D2+D3)/D1小于或等于1.5，以节省缓冲件30的用量，提高电池单体7的能量密度，减小电极组件10的膨胀力，改善电极组件10的循环性能。
可选地，(D2+D3)/D1的值可为0.9、0.95、0.98、1、1.1、1.2、1.25、1.3、1.4或1.5。
在一些实施例中，D1、D2和D3满足：0.98≤(D2+D3)/D1≤1.25。
在一些实施例中，电极组件10包括主体部14和从主体部14引出的第一极耳15和第二极耳16。主体部14包括正极涂覆区、正极活性物质层、负极涂覆区、负极活性物质层以及隔离件13。第一极耳15和第二极耳16中的一者为正极极耳，另一者为负极极耳。
在本申请中，在满充状态下，主体部14沿第一方向X的尺寸即为D4。
在一些实施例中，外壳20包括壳体21和端盖22，壳体21具有开口，端盖22盖合于开口。示例性地，壳体21包括两个第一侧壁211。
壳体21可为一侧开口的结构，端盖22设置为一个并盖合于壳体21的开口。可 替代地，壳体21也可为两侧开口的结构，端盖22设置为两个，两个端盖22分别盖合于壳体21的两个开口。
示例性地，端盖22通过焊接、粘接、卡接或其它方式连接于壳体21。
在一些实施例中，第一侧壁211为平板结构。
在一些实施例中，壳体21沿第二方向Y的一端设有开口。可选地，第一方向X垂直于第二方向Y。
在一些实施例中，壳体21包括两个第二侧壁212，两个第二侧壁212沿第三方向Z相对设置。可选地，第三方向Z垂直于第一方向X和第二方向Y。
两个第一侧壁211和两个第二侧壁212沿开口的周向交替设置。第一侧壁211沿第三方向Z的两端分别连接于两个第二侧壁212。
在一些实施例中，相邻的第一侧壁211和第二侧壁212通过弧形壁连接。
在一些实施例中，D1的值可采用下述方法测量：使用游标卡尺测量壳体21沿第一方向X的尺寸D6；使用游标卡尺测量第一侧壁211的壁厚D7；D1＝D6-2·D7。
在电池单体7的循环过程中，第一侧壁211可能会因电极组件10的膨胀而出现变形。由于第一侧壁211的靠近第二侧壁212的端部处的变形较小，因此，游标卡尺可夹持两个第一侧壁211的靠近第二侧壁212的端部，并将测出的值作为D6。
在一些实施例中，电池单体7还包括两个电极端子40，两个电极端子40可以设置在端盖22上。一个电极端子40用于与电极组件10的第一极片11电连接，另一个电极端子40用于与第二极片12电连接，以将电极组件10产生的电能引出到外壳20外。
在一些实施例中，缓冲件30可为多孔结构。缓冲件30中的微孔可用于储存电解液，在电极组件10膨胀并挤压缓冲件30时，缓冲件30的电解液可被挤出。
在一些实施例中，缓冲件30可由泡棉制成。
在一些实施例中，第一方向X平行于电池单体7的厚度方向。在电池中，多个电池单体7可以沿第一方向X堆叠。
在一些实施例中，D2和D3满足：D3≤0.25·D2。
在D2的值一定时，D3的值越大，缓冲件30的体积和重量越大，电池单体7的重量能量密度越低。发明人发现，当D3的值超过一定范围时，缓冲件30的改善电极组件10的循环性能的作用不会随着D3的增大而进一步提高；发明人经过试验，将D3的值限定为小于或等于0.25·D2，可以减小缓冲件30的用量，提高电池单体7的能量密度，并改善电极组件10的循环性能。
在一些实施例中，缓冲件30为平板结构。平板结构易于成型，且能够在电极组件10膨胀时改善电极组件10受力分布的均一性。
在一些实施例中，缓冲件30可以是长方形、圆形、椭圆形或其它形成。可选地，缓冲件30为长方形平板。
在一些实施例中，缓冲件30附接于电极组件10。
附接是指缓冲件30贴合并连接于电极组件10的表面。示例性地，缓冲件30可通过粘接剂粘接于电极组件10。
附接于电极组件10的缓冲件30可以和电极组件10一同装入壳体21内，以简化装配工艺。电极组件10还能够在电池单体7受到外部冲击时限制缓冲件30的晃动，以降低缓冲件30偏移的风险。
在一些实施例中，缓冲件30在2Mpa的压力下的压缩率f满足：1％≤f≤99％。可选地，缓冲件30在2Mpa的压力下的压缩率f满足：40％≤f≤99％。
在一些实施例中，电极组件10包括平直区10a和两个弯折区10b，两个弯折区10b分别位于平直区10a沿第三方向Z的两侧，第三方向Z垂直于第一方向X。缓冲件30在第三方向Z上的尺寸为L1，电极组件10在满充状态下沿第三方向Z的尺寸为L2，一个电极组件10在满充状态下沿第一方向X的尺寸为D4。L1、L2和D4满足：L1≥0.85(L2-D4)。
平直区10a为电极组件10的具有平直结构的区域，极片的位于平直区10a的部分大致呈平直状态。弯折区10b为电极组件10的具有弯折结构的区域，极片的位于弯折区10b的部分大体呈弯折状态。示例性地，极片的位于弯折区10b的部分大体弯折成圆弧状。
在满充状态下，弯折区10b沿第三方向Z的尺寸大体等于D4的一半，L2-D4大体为平直区10a沿第三方向Z的尺寸。
由于电极组件10的弯折区10b与第一侧壁211之间的间隙较大，所以弯折区10b产生的膨胀力较小。电极组件10的平直区10a与第一侧壁211之间的间隙较小，所以平直区10a产生的膨胀力较大。本实施例将L1的值限定为大于或等于0.85(L2-D4)，使平直区10a在第三方向Z上的85％以上的区域的膨胀能够被缓冲件30吸收，以保证平直区10a的循环性能。
在一些实施例中，在第三方向Z上，缓冲件30的两端超出平直区10a。缓冲件30可以有效地吸收平直区10a的膨胀，改善平直区10a的循环性能。
在一些实施例中，L1和L2满足：L1≤1.1·L2。在第三方向Z上，缓冲件30超过电极组件10的部分不会吸收电极组件10的膨胀，反而会增大缓冲件30的体积和重量。本实施例使L1的值小于或等于1.1·L2，以减少缓冲件30的用量，提高电池单体7的能量密度。
在一些实施例中，缓冲件30沿第一方向X在第一侧壁211的内表面上的投影的面积为S1，第一侧壁211的内表面的面积为S2，S1和S2满足：S1≤0.95·S2。
第一侧壁211的内表面会在电极组件10膨胀时挤压电极组件10，以限制电极组件10的膨胀变形。外壳20除了容纳电极组件10之外，还需要容纳其它功能性构件，所以第一侧壁211的内表面的一部分不会挤压电极组件10。本申请实施例使S1≤0.95·S2，以减小缓冲件30的整体使用量，为外壳20内的其它构件提供更多的空间，提高电池单体7的能量密度和使用寿命。
在一些实施例中，各缓冲件30在未压缩的状态下沿第一方向X的尺寸为D5，D5满足：0.1mm≤D5≤10mm。可选地，D5的值为0.1mm、0.5mm、1mm、2mm、4mm、5mm、8mm或10mm。
如果D5过小，那么为了满足要求，需要在电池单体7内设置更多数量的缓冲件 30，造成电池单体7的结构复杂，装配效率低。因此，本申请实施例将D5的值限定位于大于或等于0.1mm。
如果D5过大，那么缓冲件30的重量偏大、占用的空间偏大，造成电池单体7的能量密度偏低。因此，本申请实施例将D5的值限定为小于或等于10mm。
在一些实施例中，D5满足：0.5mm≤D5≤4mm。
图7为本申请一些实施例提供的电池单体的剖视示意图；图8为本申请一些实施例提供的电池单体的电极组件和缓冲件的局部剖视示意图。
如图7和图8所示，在一些实施例中，电极组件10包括第一极片11，第一极片11包括第一主体111和从第一主体111沿第二方向Y的一端引出的第一极耳15，第二方向Y垂直于第一方向X。缓冲件30沿第二方向Y的尺寸为H1；第一主体111设有第一活性物质层112，第一活性物质层112沿第二方向Y的尺寸为H2。H1、H2满足：H1≥0.85·H2。
电极组件10膨胀的主要原因是活性物质层在充电过程中的膨胀。本申请实施例将H1的值限定为大于或等于0.85·H2，使第一活性物质层112在第二方向Y上85％以上的区域的膨胀能够被缓冲件30吸收，以减小第一活性物质层112受到的压力，改善电极组件10的循环性能。
第一极片11可以是正极极片，也可以是负极极片。示例性地，第一极片11为负极极片，第一活性物质层112为负极活性物质层。第一主体111还包括负极集流体的负极涂覆区。
在一些实施例中，第一活性物质层112包括基体区112a和连接于基体区112a的削薄区112b，削薄区112b的厚度小于基体区112a的厚度。在第二方向Y上，削薄区112b位于基体区112a的靠近第一极耳15的一侧。在第二方向Y上，缓冲件30的两端均超出基体区112a。
在第一极片11的成型过程中，需要辊压第一活性物质层112，以增大第一活性物质层112的压实密度。本申请实施例减小了削薄区112b的厚度，以在辊压过程中减小第一主体111和第一极耳15交界处的应力集中，降低第一极耳15开裂的风险。
相对于削薄区112b，基体区112a膨胀时产生的膨胀力更大，因此，本申请实施例使缓冲件30沿第二方向Y的两端超出基体区112a，以有效地吸收基体区112a的膨胀，改善电极组件10的循环性能。
在一些实施例中，电极组件10还包括隔离件13，隔离件13与第一主体111层叠设置。隔离件13沿第二方向Y的尺寸为H3；H1、H3满足：H1≤1.1·H3。
隔离件13用于将第一主体111与第二极片12绝缘隔离。
在第二方向Y上，隔离件13超出隔离件13的部分不会吸收电极组件10的膨胀，反而会增大缓冲件30的体积和重量。本实施例使H1的值小于或等于1.1·H3，以减少缓冲件30的用量，提高电池单体7的能量密度。
在一些实施例中，在第二方向Y上，缓冲件30的两端均不超出隔离件13，以减少缓冲件30的用量，降低缓冲件30与其它构件干涉的风险，提高电池单体7的能量密度。
图9为本申请另一些实施例提供的电池单体的结构示意图。
如图9所示，在一些实施例中，电极组件10为多个。至少相邻的两个电极组件10之间设有缓冲件30。
将缓冲件30设置在相邻的两个电极组件10之间，可以在电池单体7受到外部冲击时降低缓冲件30晃动的风险。
图10为本申请又一些实施例提供的电池单体的结构示意图。如图10所示，在一些实施例中，电极组件10为多个，缓冲件30为多个。
示例性地，电极组件10为两个，缓冲件30为两个。两个电极组件10相邻设置并构成电极单元，两个缓冲件30分别位于电极单元沿第一方向X的两侧。
图11为本申请再一些实施例提供的电池单体的结构示意图。如图11所示，在一些实施例中，电极组件10为四个，缓冲件30为两个。四个电极组件10相邻设置并构成电极单元，两个缓冲件30分别位于电极单元沿第一方向X的两侧。
根据本申请的一些实施例，本申请还提供了一种电池，其包括多个上述任一实施例提供的电池单体。
根据本申请的一些实施例，本申请还提供了一种用电装置，其包括上述任一实施例提供的电池单体，电池单体用于为用电装置提供电能。
根据本申请的一些实施例，参照图10，本申请实施例的电池单体7包括外壳20、两个电极组件10和两个缓冲件30。外壳20包括沿第一方向X相对设置的两个第一侧壁211，两个第一侧壁211沿第一方向X的间距为D1。两个电极组件10容纳于外壳20内，在满充状态下，两个电极组件10沿第一方向X的尺寸之和为D2。两个电极组件10构成电极单元，两个缓冲件30分别位于电极单元沿第一方向X的两侧。缓冲件30被配置为可压缩地，各缓冲件30在未压缩的状态下沿第一方向X的尺寸为D5，两个缓冲件30在未压缩的状态下沿第一方向X的尺寸之和为D3。D1、D2和D3满足：0.9≤(D2+D3)/D1≤1.5。
图12为本申请一些实施例提供的电池单体的制造方法的流程示意图。
如图12所示，本申请实施例提供了一种电池单体的制造方法，其包括：
S100、提供外壳，外壳包括沿第一方向相对设置的两个第一侧壁；
S200、提供电极组件和缓冲件；
S300、将电极组件和缓冲件安装到外壳内。
两个第一侧壁沿第一方向的间距为D1。电极组件设置为M个，M为大于0的正整数。在满充状态下，M个电极组件沿第一方向的尺寸之和为D2。缓冲件为N个，N为大于0的正整数；N个缓冲件与M个电极组件沿第一方向层叠。缓冲件被配置为可压缩地，N个缓冲件在未压缩的状态下沿第一方向的尺寸之和为D3。D1、D2和D3满足：0.9≤(D2+D3)/D1≤1.5。
需要说明的是，通过上述电池单体的制造方法制造出的电池单体的相关结构，可参见上述各实施例提供的电池单体。
在基于上述的电池单体的制造方法制造电池单体时，不必按照上述步骤依次进行，也就是说，可以按照实施例中提及的顺序执行步骤，也可以不同于实施例中提及 的顺序执行步骤，或者若干步骤同时执行。例如，步骤S100、S200的执行不分先后，也可以同时进行。
图13为本申请一些实施例提供的电池单体的制造系统的示意性框图。
如图13所示，本申请实施例提供了一种电池单体的制造系统90，其包括第一提供装置91、第二提供装置92和组装装置93。第一提供装置91用于提供外壳，外壳包括沿第一方向相对设置的两个第一侧壁。第二提供装置92用于提供电极组件和缓冲件。组装装置93用于将电极组件和缓冲件安装到外壳内。两个第一侧壁沿第一方向的间距为D1。电极组件设置为M个，M为大于0的正整数。在满充状态下，M个电极组件沿第一方向的尺寸之和为D2。缓冲件为N个，N为大于0的正整数；N个缓冲件与M个电极组件沿第一方向层叠。缓冲件被配置为可压缩地，N个缓冲件在未压缩的状态下沿第一方向的尺寸之和为D3。D1、D2和D3满足：0.9≤(D2+D3)/D1≤1.5。
以下结合实施例进一步说明本申请。
为了使本申请的发明目的、技术方案和有益技术效果更加清晰，以下结合实施例进一步详细描述本申请。但是，应当理解的是，本申请的实施例仅仅是为了解释本申请，并非为了限制本申请，且本申请的实施例并不局限于说明书中给出的实施例。实施例中未注明具体实验条件或操作条件的按常规条件制作，或按材料供应商推荐的条件制作。
实施例1可按照下述步骤制备：
(i)将正极活性物质NCM523、导电剂乙炔黑、粘结剂PVDF按质量比96:2:2进行混合，加入溶剂NMP，在真空搅拌机作用下搅拌至体系呈均一状，获得正极浆料；将正极浆料均匀涂覆在铝箔上，室温晾干后转移至烘箱继续干燥，然后经过冷压、分切、裁片得到正极极片。
(ii)将负极活性物质石墨或石墨与其它活性物质按不同质量比得到的混合物、导电剂乙炔黑、增稠剂CMC、粘结剂SBR按质量比96.4:1:1.2:1.4进行混合，加入溶剂去离子水，在真空搅拌机作用下搅拌至体系呈均一状，获得负极浆料；将负极浆料均匀涂覆在铜箔上，室温晾干后转移至烘箱继续干燥，然后经过冷压、分切、裁片得到负极极片。
(iii)将碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照按体积比1:1:1进行混合得到有机溶剂，接着将充分干燥的锂盐LiPF6溶解于混合后的有机溶剂中，配制成浓度为1mol/L的电解液。
(iv)以12μm厚的聚丙烯膜作为隔离件。
(v)将正极极片、隔离件及负极极片层叠在一起并卷绕为多圈，卷绕后再压平为扁平状，以制备出电极组件。
(Ⅵ)将两个电极组件和两个缓冲件层叠并安装到壳体内，然后焊接端盖和壳体，并经过注液、静置、化成、整形等工序，获得电池单体。
在步骤(Ⅵ)中，如图14所示，两个缓冲件30和两个电极组件10沿第一方向X层叠，壳体21包括沿第一方向X相对设置的两个第一侧壁211。使用游标卡尺，测出两个第一侧壁211沿第一方向X的间距D1为27mm。在将缓冲件30装入壳体21之前， 使用游标卡尺测得缓冲件30的厚度D5为0.45mm；对应地，两个缓冲件30在在压缩的状态下沿第一方向X的尺寸之和为D3，D3为0.9mm。
根据上述制备步骤制备出两个电池单体7，分别进行界面检测和循环性能检测。
界面检测：
在常温环境下，对一个电池单体7以0.33C倍率充电，直至满充。电池单体7满充后，对电池单体7进行拆解，并使用游标卡尺测出各电极组件10在满充状态下沿第一方向X的尺寸。完成尺寸测量后，对电极组件10进行进一步拆解，并观察负极极片的界面状态。
经过测量计算后，两个电极组件10沿第一方向X的尺寸之和D2为25.6mm。
循环性能检测：
将另一个电池单体7固定在夹具上，夹具从两侧夹持电池单体7的两个第一侧壁211，并对第一侧壁211施加3000N的夹紧力。夹具设有压力传感器，以实时检测第一侧壁211与夹具之间的压力F。
在常温环境下，将电池单体7以1C倍率充电、以1C倍率放电，进行满充满放循环测试，直至电池单体7的容量衰减至初始容量的90％。
在循环的过程中，实时监控电池单体7的状态。当电池单体7的容量衰减至初始容量的90％时，记录电池单体7循环的圈数，并计算出电池单体7的膨胀力的增长量ΔF，ΔF＝F-3000N。
示例性地，夹具包括两个夹板，两个夹板从两侧夹持电池单体7并分别与两个第一侧壁211相对，夹板和对应的第一侧壁211之间可设置缓冲垫。
实施例2：实施例2的电池单体的制备方法和检测方法参照实施例1，不同之处在于D3为1.4mm。
实施例3：实施例3的电池单体的制备方法和检测方法参照实施例1，不同之处在于D3为4.1mm。
实施例4：实施例4的电池单体的制备方法和检测方法参照实施例1，不同之处在于D3为8.15mm。
实施例5：实施例5的电池单体的制备方法和检测方法参照实施例1，不同之处在于D3为12.2mm。
实施例6：实施例6的电池单体的制备方法和检测方法参照实施例1，不同之处在于D3为14.9mm。
实施例7：实施例7的电池单体的制备方法和检测方法参照实施例1，不同之处在于D3为0.7mm，D2为23.6mm。
实施例8：实施例8的电池单体的制备方法和检测方法参照实施例1，不同之处在于D3为2.1mm，D2为23.6mm。
对比例1：对比例1的电池单体的制备方法和检测方法参照实施例1，不同之处在于，D2为24.3mm，且对比例1内部不设缓冲件(即D3为0)。
对比例2：对比例1的电池单体的制备方法和检测方法参照实施例1，不同之处在于，D2为25.6mm，且对比例1内部不设缓冲件(即D3为0)。
对比例3：对比例1的电池单体的制备方法和检测方法参照实施例1，不同之处在于，D2为26.4mm，且对比例1内部不设缓冲件(即D3为0)。
对比例4：对比例4的电池单体的制备方法和检测方法参照实施例1，不同之处在于D3为0.6mm，D2为21mm。
对比例5：对比例5的电池单体的制备方法和检测方法参照实施例1，不同之处在于D3为17.6mm。
实施例1-8和对比示例1-5的评估结果示出于表1中。
表1
需要说明的是，沿电极组件卷绕的轴向，褶皱的尺寸与极片的尺寸之比小于5％，视为无褶皱，褶皱的尺寸与极片的尺寸之比为5％-30％，视为轻微褶皱，褶皱的尺寸与极片的尺寸之比大于30％，视为严重褶皱。
参照实施例1-8与对比例1-3，本申请实施例通过设置缓冲件，可以减少极片在电池单体初次充电时出现褶皱的风险，减小电池单体在循环过程中产生的膨胀力，延长电池单体循环的圈数，改善电池单体的循环性能。
参照实施例1-8与对比例4-5，本申请实施例将(D2+D3)/D1的值限定在0.9- 1.5之间，可以减少极片在电池单体初次充电时出现褶皱的风险，减小电池单体在循环过程中产生的膨胀力，延长电池单体循环的圈数，改善电池单体的循环性能。
虽然已经参考优选实施例对本申请进行了描述，但在不脱离本申请的范围的情况下，可以对其进行各种改进并且可以用等效物替换其中的部件，尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (19)

  1. 一种电池单体，包括：
    外壳，包括沿第一方向相对设置的两个第一侧壁，两个所述第一侧壁沿所述第一方向的间距为D1；
    M个电极组件，容纳于所述外壳内，在满充状态下，M个所述电极组件沿所述第一方向的尺寸之和为D2，所述M为大于0的正整数；
    N个缓冲件，容纳于所述外壳内，并与M个所述电极组件沿所述第一方向层叠；所述缓冲件被配置为可压缩地，N个所述缓冲件在未压缩的状态下沿所述第一方向的尺寸之和为D3，所述N为大于0的正整数；
    其中，D1、D2和D3满足：0.9≤(D2+D3)/D1≤1.5。
  2. 根据权利要求1所述的电池单体，其中，D1、D2和D3满足：0.98≤(D2+D3)/D1≤1.25。
  3. 根据权利要求1或2所述的电池单体，其中，所述第一方向平行于所述电池单体的厚度方向。
  4. 根据权利要求1-3任一项所述的电池单体，其中，D2和D3满足：D3≤0.25·D2。
  5. 根据权利要求1-4任一项所述的电池单体，其中，所述电极组件包括第一极片，所述第一极片包括第一主体和从所述第一主体沿第二方向的一端引出的第一极耳，所述第二方向垂直于所述第一方向；
    所述缓冲件沿所述第二方向的尺寸为H1；所述第一主体设有第一活性物质层，所述第一活性物质层沿所述第二方向的尺寸为H2；
    H1、H2满足：H1≥0.85·H2。
  6. 根据权利要求5所述的电池单体，其中，所述第一活性物质层包括基体区和连接于所述基体区的削薄区，所述削薄区的厚度小于所述基体区的厚度；
    在所述第二方向上，所述削薄区位于所述基体区的靠近所述第一极耳的一侧；
    在所述第二方向上，所述缓冲件的两端均超出所述基体区。
  7. 根据权利要求5或6所述的电池单体，其中，所述电极组件还包括隔离件，所述隔离件与所述第一主体层叠设置；
    所述隔离件沿所述第二方向的尺寸为H3；
    H1、H3满足：H1≤1.1·H3。
  8. 根据权利要求7所述的电池单体，其中，在所述第二方向上，所述缓冲件的两端均不超出所述隔离件。
  9. 根据权利要求1-8任一项所述的电池单体，其中，所述电极组件包括平直区和两个弯折区，两个所述弯折区分别位于所述平直区沿第三方向的两侧，所述第三方向垂直于所述第一方向；
    所述缓冲件在所述第三方向上的尺寸为L1，所述电极组件在满充状态下沿所述第三方向的尺寸为L2，一个所述电极组件在满充状态下沿所述第一方向的尺寸为D4；
    L1、L2和D4满足：L1≥0.85(L2-D4)。
  10. 根据权利要求9所述的电池单体，其中，在所述第三方向上，所述缓冲件的两端超出所述平直区。
  11. 根据权利要求9或10所述的电池单体，其中，L1和L2满足：L1≤1.1·L2。
  12. 根据权利要求1-11任一项所述的电池单体，其中，所述缓冲件沿所述第一方向在所述第一侧壁的内表面上的投影的面积为S1，所述第一侧壁的内表面的面积为S2，S1和S2满足：S1≤0.95·S2。
  13. 根据权利要求1-12任一项所述的电池单体，其中，各所述缓冲件在未压缩的状态下沿所述第一方向的尺寸为D5，D5满足：0.1mm≤D5≤10mm。
  14. 根据权利要求1-13任一项所述的电池单体，其中，所述缓冲件在2Mpa的压力下的压缩率f满足：1％≤f≤99％。
  15. 根据权利要求1-14任一项所述的电池单体，其中，所述缓冲件附接于所述电极组件。
  16. 根据权利要求1-15任一项所述的电池单体，其中，所述电极组件为多个；
    至少相邻的两个所述电极组件之间设有所述缓冲件。
  17. 根据权利要求1-16任一项所述的电池单体，其中，所述缓冲件为平板结构。
  18. 一种电池，包括多个根据权利要求1-17任一项所述的电池单体。
  19. 一种用电装置，包括根据权利要求1-17任一项所述的电池单体，所述电池单体用于提供电能。
PCT/CN2023/084267 2022-04-12 2023-03-28 电池单体、电池以及用电装置 WO2023197858A1 (zh)

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CN207883842U (zh) * 2018-02-27 2018-09-18 江苏海基新能源股份有限公司 长寿命方形锂离子电池
CN109309257A (zh) * 2018-09-30 2019-02-05 联想(北京)有限公司 一种电池及电池生产方法
CN113394490A (zh) * 2021-05-28 2021-09-14 东莞塔菲尔新能源科技有限公司 一种二次电池
KR20220015252A (ko) * 2020-07-30 2022-02-08 주식회사 엘지에너지솔루션 탄성부재를 포함하는 파우치형 전지셀 및 이를 포함하는 전지팩
WO2023283807A1 (zh) * 2021-07-13 2023-01-19 宁德时代新能源科技股份有限公司 电池单体、电池及用电装置

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CN207883842U (zh) * 2018-02-27 2018-09-18 江苏海基新能源股份有限公司 长寿命方形锂离子电池
CN109309257A (zh) * 2018-09-30 2019-02-05 联想(北京)有限公司 一种电池及电池生产方法
KR20220015252A (ko) * 2020-07-30 2022-02-08 주식회사 엘지에너지솔루션 탄성부재를 포함하는 파우치형 전지셀 및 이를 포함하는 전지팩
CN113394490A (zh) * 2021-05-28 2021-09-14 东莞塔菲尔新能源科技有限公司 一种二次电池
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