WO2023283807A1 - 电池单体、电池及用电装置 - Google Patents

电池单体、电池及用电装置 Download PDF

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Publication number
WO2023283807A1
WO2023283807A1 PCT/CN2021/106110 CN2021106110W WO2023283807A1 WO 2023283807 A1 WO2023283807 A1 WO 2023283807A1 CN 2021106110 W CN2021106110 W CN 2021106110W WO 2023283807 A1 WO2023283807 A1 WO 2023283807A1
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WO
WIPO (PCT)
Prior art keywords
battery cell
battery
buffer
cell
encapsulation
Prior art date
Application number
PCT/CN2021/106110
Other languages
English (en)
French (fr)
Inventor
何建福
叶永煌
刘倩
孙婧轩
徐晓富
孙雪阳
金海族
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.)
Filing date
Publication date
Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to CN202180073500.6A priority Critical patent/CN116391292A/zh
Priority to EP21949601.5A priority patent/EP4220830A1/en
Priority to PCT/CN2021/106110 priority patent/WO2023283807A1/zh
Publication of WO2023283807A1 publication Critical patent/WO2023283807A1/zh
Priority to US18/357,389 priority patent/US11855297B2/en

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    • 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
    • H01M50/244—Secondary casings; Racks; Suspension devices; Carrying devices; Holders characterised by their mounting method
    • 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
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/103—Primary casings; Jackets or wrappings characterised by their shape or physical structure prismatic or rectangular
    • 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
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/105—Pouches or flexible bags
    • 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
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H01M50/207—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape
    • H01M50/209—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for prismatic or rectangular 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
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H01M50/207—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape
    • H01M50/211—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for pouch 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
    • H01M50/20—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
    • H01M50/24—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 from their environment, e.g. from corrosion
    • 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
    • H01M50/289—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders characterised by spacing elements or positioning means within frames, racks or packs
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • 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, in particular to a battery cell, a battery and an electrical device.
  • the inventors of the present application have found in research that during the use of charging and discharging of existing batteries, as the temperature of the battery core increases and the use time increases, the battery core will swell, and then the battery case will be squeezed, giving lithium The use of batteries carries risks.
  • the present application provides a battery cell, a battery and an electrical device for solving the above problems in the prior art.
  • the embodiment of the present application provides a battery cell, including:
  • the buffer has an accommodating cavity, and the accommodating
  • the outer periphery of the cavity includes at least one encapsulation structure, the encapsulation structure includes at least one level of encapsulation area with a predetermined length, and when the pressure in the accommodating cavity exceeds the encapsulation strength of the encapsulation structure, the encapsulation area opens and forms a The accommodating cavity communicates with a buffer space.
  • the buffer member corresponding to the side wall of the battery cell By arranging the buffer member corresponding to the side wall of the battery cell, on the one hand, the initial gap between the battery cell and the casing can be effectively filled, and the phenomenon of loosening and lithium deposition in the winding structure of the battery cell can be avoided;
  • the core expands during use, the pressure caused by the expansion of the battery core is relieved, and the influence of the expansion of the battery core on the pole piece is reduced.
  • the side wall includes an intermediate side wall portion located in the middle region of the two ends in the height direction of the cell, and the buffer member is arranged correspondingly to the intermediate side wall portion.
  • a buffer space can be provided for the part with the largest expansion force of the battery cell, and the pressure caused by the expansion of the battery cell can be relieved to the greatest extent.
  • the buffer member is disposed between the electric core and the side wall of the casing, and/or, the buffer member is sandwiched between adjacent electric cores.
  • the buffer member By arranging the buffer member at different positions of the battery cell, the problem caused by the expansion of the battery cell can be solved to the greatest extent according to the characteristics of the battery cell.
  • the encapsulation structure is located at one or both ends of the buffer along the height direction of the battery core.
  • This arrangement can make full use of the space in the height direction of the battery core during the cracking process of the packaging structure. On the one hand, it can fill the space in the height direction of the battery core, and on the other hand, it is also convenient for the buffer member to be placed in the battery cell. Under the action of the expansion force of the core, it cracks in the direction of the height of the cell.
  • the height of the accommodating cavity is 10-90% of the height of the electric core.
  • the package structure By setting the height of the accommodating cavity to be proportional to the height of the electric core, the package structure can be arranged in the space in the direction of the height of the electric core, so that the setting of the buffer member is more flexible.
  • the encapsulation structure includes at least two stages of encapsulation regions with different encapsulation strengths, so that as the pressure in the accommodating chamber increases, the encapsulation regions open step by step, and communicate with the accommodating chamber step by step. buffer space.
  • the packaging area is gradually opened, and the space of the accommodating cavity can be gradually released as the expansion force of the battery core increases.
  • the at least two stages of the packaging regions are arranged continuously; and/or, the at least two stages of the packaging regions are arranged at intervals, and a buffer of a predetermined length is provided between adjacent two stages of the packaging regions Area.
  • the accommodation cavity can gradually release the space with the increase of the expansion force of the battery cell, avoiding a sudden change in space, making the resistance of the buffer member on the battery cell more stable, and greatly improving the battery cell. service life.
  • Setting the interval between the encapsulation areas and setting the buffer zone between the encapsulation areas can adjust the size of the free space of the encapsulation area, and the setting is flexible.
  • the packaging regions of the at least two stages are arranged along the height direction of the electric core, and the packaging regions farther from the receiving cavity have greater packaging strength.
  • the above arrangement can make it very easy for the buffer member to gradually expand toward the height of the cell, and the space can be gradually released as the expansion pressure of the cell increases.
  • the pressure in the accommodating cavity is greater than or equal to the air pressure inside the battery cell.
  • the accommodation cavity Since the pressure in the accommodation cavity is greater than the air pressure inside the battery cell, the accommodation cavity generates a certain pressure on the battery cell, so that the battery cell can also maintain a full state when the group margin is low, thereby preventing Lithium precipitation caused by electrode sheet wrinkles is eliminated.
  • the packaging strength of the packaging structure is 0.1-50 MPa.
  • the setting of the packaging strength comprehensively considers the internal pressure of the housing chamber and the pressure brought by the expansion of the battery cell.
  • the internal pressure of the housing chamber can generate pressure on the battery cell in the initial state, avoiding lithium deposition in the battery cell.
  • the pressure inside the containing chamber can gradually open the packaging structure.
  • the cell is a square cell, and the buffer is arranged at one or both ends of the cell in the thickness direction; and/or, the buffer is arranged at the width of the cell. One or both ends of the direction.
  • the buffer member By flexibly arranging the buffer member in all directions of the battery cell, the expansion force of the battery cell in all directions can be relieved.
  • the width of the accommodating cavity is 50% of the width of the cell. ⁇ 100%.
  • a cross-section of the accommodating cavity in the height direction of the electric core is ring-shaped, and continuously surrounds the electric core.
  • This kind of arrangement can form a buffer around the battery cell, on the one hand, avoid lithium deposition caused by the shaking of the battery cell, and on the other hand, when the battery cell expands, it can be in all directions around the battery cell.
  • the expansion of the cell provides space.
  • the material of the cushioning member has an outer protective layer and an inner sealing layer, and the packaging area is formed by heat sealing the inner sealing layer.
  • the manufacture is simple, the sealing effect is good, and it is easy to manufacture various buffer parts suitable for the structure of the electric core.
  • the accommodating cavity is filled with inert fluid.
  • the expansion of the accommodating cavity of the buffer member due to the substances or materials contained in it is avoided when the temperature of the battery core rises, thereby avoiding the expansion and extrusion of the buffer member itself The expansion space of the battery core.
  • the present application provides a battery, which includes the battery cell in the above embodiment.
  • the present application provides an electric device, which includes the battery in the above embodiment, and the battery is used to provide electric energy.
  • FIG. 1 is a schematic structural diagram of a vehicle provided in an embodiment of the present application.
  • Fig. 2 is a schematic diagram of an exploded structure of a battery provided in an embodiment of the present application
  • FIG. 3 is a cross-sectional view of a battery cell provided in an embodiment of the present application.
  • Fig. 4 is a sectional view of the cushioning member provided by the embodiment of the present application.
  • Fig. 5 is a sectional view of another battery cell provided by the embodiment of the present application.
  • Figure 6a is a schematic diagram of another buffer provided in the embodiment of the present application.
  • Fig. 6b is a schematic diagram of the second buffer provided in the embodiment of the present application.
  • Fig. 6c is a schematic diagram of the third buffer provided in the embodiment of the present application.
  • Fig. 6d is a schematic diagram of the fourth buffer provided in the embodiment of the present application.
  • Fig. 6e is a schematic diagram of the fifth buffer provided in the embodiment of the present application.
  • Figure 6f is a schematic diagram of the sixth buffer provided in the embodiment of the present application.
  • Fig. 7 is a diagram of the use state of the buffer provided by the embodiment of the present application.
  • Fig. 8 is a cross-sectional view of another buffer provided in the embodiment of the present application.
  • Fig. 9 is a diagram of the use state of another buffer provided by the embodiment of the present application.
  • Fig. 10 is an exploded view of a battery cell provided by the embodiment of the present application.
  • Fig. 11 is an exploded view of another battery cell provided by the embodiment of the present application.
  • Fig. 12 is a schematic diagram of the ring buffer provided by the embodiment of the present application.
  • Fig. 13 is a schematic diagram of a rectangular buffer provided in an embodiment of the present application.
  • Fig. 14 is a structural diagram of the buffer material provided by the embodiment of the present application.
  • Fig. 15 is a schematic diagram of the forming of the buffer provided in the embodiment of the present application.
  • Fig. 16 is a schematic structural diagram of a battery provided in an embodiment of the present application.
  • Fig. 17 is a cross-sectional view of a battery cell in Test 1 provided by the embodiment of the present application.
  • Fig. 18 is a cross-sectional view of a battery cell in Test 2 provided by the embodiment of the present application.
  • FIG. 19 is a cross-sectional view of a battery cell in Test 3 provided in the embodiment of the present application.
  • Battery cell 1000 housing 100, battery cell 200, first end 201, first side wall 203, tab 205, first battery cell 210, second battery cell 220, first side wall 2203 of the second battery cell , the first corner 2205 of the second cell, the buffer member 300, the aluminum-plastic film 301, the packaging structure 3010, the first buffer area 3011, the first packaging area 3012, the second buffer area 3013, the second packaging area 3014, and the third buffer Region 3015, third package area 3016, housing cavity 305, first buffer member 310, first package structure 3110, second buffer member 320, second package structure 3210, ring buffer member 330, ring package structure 3310, end cap 400 , a vehicle 2000, a battery 2100, a bus component 2101, a controller 2200, a motor 2300, a box 2110, an upper box 2111, and a lower box 2112.
  • multiple refers to more than two (including two), similarly, “multiple groups” refers to more than two groups (including two), and “multiple pieces” refers to More than two pieces (including two pieces).
  • Power batteries are not only used in energy storage power systems such as hydraulic, thermal, wind and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric vehicles, as well as military equipment and aerospace and other fields . With the continuous expansion of power battery application fields, its market demand is also constantly expanding.
  • the inventors of the present application noticed that as the positive electrode active material and the negative electrode active material intercalate or de-ion during the charge-discharge cycle of the battery, the cell will bulge, that is, the positive electrode sheet and the negative electrode sheet expand outward. Especially in the middle area of the stack or winding of the cell, the expansion phenomenon is more serious.
  • the expansion of the pole piece has adverse effects on the performance and service life of the battery. For example, it may affect the infiltration of the electrolyte on the pole piece, causing changes in the ion transmission path and causing the problem of lithium analysis; when the pole piece is subjected to a large extrusion force for a long time , It may also break and cause the risk of short circuit in the battery and so on.
  • the electrolyte of the battery will be continuously consumed during the charge-discharge cycle. After the battery cell has been used for a certain period of time, the electrolyte may even be partially depleted, and the swelling of the cell will further aggravate the local electrolyte shortage.
  • an elastic support plate can be installed inside the cell. Through the elastic contraction of the elastic plate, space is left for the cell to expand, so as to solve the problem of the positive and negative electrodes of the lithium-ion battery after multiple charge and discharge cycles.
  • the problem that the contact with the diaphragm is not tight and gradually loosens.
  • the applicant found that due to the large thickness and heavy weight of the elastic support plate, it will occupy more space inside the battery cell, which will also lead to an increase in the mass of the battery cell, resulting in an increase in the energy density of the battery cell. Big loss.
  • the elastic support plate contains a large number of metal parts, there will be a risk of dissolution of the metal parts during long-term use, and the dissolved metal ions will be precipitated on the surface of the pole piece, causing risks such as puncture of the separator.
  • the elastic The support plate will result in less compressible space inside the cell, which will lead to a sharp increase in the expansion force of the cell life in the later stages of use.
  • the inventor of the present application has designed a new type of battery cell after in-depth research. Buffer, the buffer will gradually release the expansion buffer space with the gradual increase of the expansion force of the battery cell, which solves the problem of battery performance deterioration caused by the expansion of the battery during the use of the battery.
  • the battery cells disclosed in the embodiments of the present application can be used, but not limited to, in electric devices such as vehicles, ships or aircrafts.
  • the power system composed of the battery cells and batteries disclosed in this application can be used to form the power consumption device, which is beneficial to alleviate and automatically adjust the deterioration of the expansion force of the battery cell, and improve the stability of battery performance and battery life.
  • the embodiment of the present application provides an electric device using a battery as a power source.
  • the electric device can be, but not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, and the like.
  • electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric boat toys, electric airplane toys, etc.
  • spacecraft may include airplanes, rockets, space shuttles, spaceships, etc.
  • a vehicle 2000 as an electric device according to an embodiment of the present application is taken as an example for description.
  • FIG. 1 is a schematic structural diagram of a vehicle 2000 provided in an embodiment of the present application.
  • the vehicle 2000 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.
  • the interior of the vehicle 2000 is provided with a battery 2100 , and the battery 2100 may be provided at the bottom, head, or tail of the vehicle 2000 .
  • the battery 2100 can be used to supply power to the vehicle 2000 , for example, the battery 2100 can be used as an operating power source of the vehicle 2000 .
  • the vehicle 2000 may further include a controller 2200 and a motor 2300 , the controller 2200 is used to control the battery 2100 to supply power to the motor 2300 , for example, for starting, navigating and running the vehicle 2000 .
  • the battery 2100 can not only be used as an operating power source for the vehicle 2000 , but also can be used as a driving power source for the vehicle 2000 to provide driving power for the vehicle 2000 instead of or partially replacing fuel oil or natural gas.
  • FIG. 2 is an exploded view of a battery 2100 provided in an embodiment of the present application.
  • the battery 2100 includes a case body 2110 and a battery cell 1000 housed in the case body 2110 .
  • the box body 2110 is used to provide an accommodation space for the battery cell 1000 , and the box body 2110 may adopt various structures.
  • the box body 2110 may include an upper box body 2111 and a lower box body 2112, the upper box body 2111 and the lower box body 2112 cover each other, and the upper box body 2111 and the lower box body 2112 jointly define an The accommodation space of 1000 units.
  • the lower box body 2112 can be a hollow structure with one end open, and the upper box body 2111 can be a plate-shaped structure, and the upper box body 2111 covers the opening side of the lower box body 2112, so that the upper box body 2111 and the lower box body 2112 jointly define Out of the accommodation space; the upper box 2111 and the lower box 2112 can also be hollow structures with one side opening, and the opening side of the upper box 2111 is covered with the opening side of the lower box 2112.
  • the box body 2110 formed by the upper box body 2111 and the lower box body 2112 may be in various shapes, such as a cylinder, a cuboid, and the like.
  • the battery 2100 mentioned in the embodiment of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.
  • the battery 2100 mentioned in this application may include a battery module or a battery pack or the like.
  • Mixed connection means that a plurality of battery cells 1000 are both connected in series and in parallel.
  • a plurality of battery cells 1000 can be directly connected in series, in parallel or mixed together, and then the whole composed of a plurality of battery cells 1000 is accommodated in the box 2110; of course, a plurality of battery cells 1000 can also be connected in series first
  • a battery 2100 in the form of a battery module is formed either in parallel or in series, and multiple battery modules are connected in series, in parallel or in series to form a whole and accommodated in the box 2110 .
  • the battery 2100 may also include other structures, for example, the battery 2100 may also include a bus component for realizing electrical connection between a plurality of battery cells 1000 .
  • each battery cell 1000 may be a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery or a magnesium-ion battery, but is not limited thereto.
  • the battery cell 1000 may be in the form of a cylinder, a flat body, a cuboid or other shapes.
  • FIG. 3 is a cross-sectional view of the battery cell 1000 provided by some embodiments of the present application along the Y-axis direction.
  • the battery cell 1000 refers to the smallest independent unit constituting a battery. As shown in FIG. 3 , the battery cell 1000 includes a case 100 , a cell 200 , an end cap 400 and other functional components.
  • the end cap 400 refers to a component that covers the opening of the housing 100 to isolate the internal environment of the battery cell from the external environment.
  • the shape of the end cap 400 can be adapted to the shape of the housing 100 .
  • the end cap 400 can be made of a material (such as aluminum alloy) with a certain hardness and strength, so that the end cap is not easily deformed when it is squeezed and collided, so that the battery cell can have higher structural strength , safety performance can also be improved.
  • Functional components such as electrode terminals can be provided on the end cap. The electrode terminals can be used for electrical connection with the battery cells, so as to output or input the electric energy of the battery cells.
  • the end cap may also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold value.
  • the material of the end cap can also be various, for example, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not particularly limited in this embodiment of the present application.
  • an insulator can also be provided inside the end cover, and the insulator can be used to isolate the electrical connection components in the housing from the end cover, so as to reduce the risk of short circuit.
  • the insulating member may be plastic, rubber or the like.
  • the casing 100 is a component used to cooperate with the end cap 400 to form the internal environment of the battery cell, wherein the formed internal environment can be used to accommodate the battery cell, electrolyte and other components.
  • the housing 100 and the end cover 400 may be independent components, and an opening may be provided on the housing 100 , and the internal environment of the battery cell is formed by making the end cover cover the opening at the opening.
  • the end cover and the housing can also be integrated.
  • the end cover and the housing can form a common connection surface before other components enter the housing.
  • the end Cover the housing.
  • the housing can be in various shapes and dimensions, such as cuboid, cylinder, hexagonal prism, etc.
  • the shape of the housing can be determined according to the specific shape and size of the battery cell assembly.
  • the housing can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not particularly limited in this embodiment of the present application.
  • the battery cell 200 is a part where the electrochemical reaction occurs in the battery cell 1000 .
  • the housing may contain one or more cells.
  • the battery core is mainly formed by winding or stacking the positive electrode sheet and the negative electrode sheet, and usually a separator is provided between the positive electrode sheet and the negative electrode sheet.
  • the parts of the positive electrode sheet and the negative electrode sheet with the active material constitute the main body of the cell assembly, and the parts of the positive electrode sheet and the negative electrode sheet without the active material respectively constitute tabs.
  • the positive pole tab and the negative pole tab can be located at one end of the main body together or at two ends of the main body respectively.
  • the embodiment of the present application provides a battery cell 1000 , including a casing 100 and at least one battery cell 200 . At least one battery cell 200 is accommodated in the casing 100 .
  • the battery cell 1000 also includes a buffer 300 .
  • the buffer member 300 is accommodated in the casing 100 and is arranged corresponding to the side wall of the battery cell 200 .
  • the buffer member 300 has a receiving cavity 305 , and the outer periphery of the receiving cavity 305 includes at least one packaging structure 3010 .
  • the package structure 3010 includes at least one package region 3012 with a predetermined length. When the pressure in the cavity 305 exceeds the package strength of the package structure 3010 , the package region 3012 opens and forms a buffer space communicating with the cavity 305 .
  • the buffer member 300 is housed in the casing 100 , and is a chamber structure with a chamber 305 inside and a closed periphery.
  • the cushioning member 300 may be a bag-shaped structure, which may be formed by folding a piece of flexible material in half and sealing the edges, or by placing two pieces of flexible material opposite each other and then sealing the edges.
  • the buffer member 300 is disposed corresponding to the first side wall 203 of the battery cell 200 , filling the gap between the housing 100 and the first side wall 203 of the battery cell 100 .
  • the housing 100 provides initial pores for the expansion of the battery cell 200 during use, but due to the existence of the initial pores, the activity space of the battery cell 200 in the housing 100 will be enlarged, so that the battery cell 200 The winding structure is loose, and then the positive and negative electrode sheets are wrinkled, which leads to the lithium precipitation problem.
  • the buffer member 300 is provided in the casing 100, which can effectively fill up the gap and avoid the problem of lithium deposition on the electrode sheet.
  • the outer periphery of the accommodating cavity 305 of the buffer member 300 includes at least one encapsulation structure 3010, and the encapsulating structure 3010 is used to seal the accommodating cavity.
  • An encapsulation structure 3010 may be provided on the outer periphery of the accommodation cavity 305, so that when the battery core 200 expands with the increase of battery life, the accommodation cavity 305 can gradually expand with the expansion of the battery core 200. Increase volume.
  • a plurality of encapsulation structures 3010 can also be arranged on the outer periphery of the housing cavity 305, and the increased volume can be set according to the internal space layout of the battery cell casing 100, so as to make full use of these internal spaces and alleviate the expansion of the battery cell 100. pressure.
  • the encapsulation area 3012 is a structural area where the encapsulation material on the outer periphery of the cushioning member 300 is pressed into one structure. After the encapsulation material in the encapsulation area is extruded into a layer of integral material, it cannot form an accommodating cavity.
  • the packaging area 3012 can be formed with different thicknesses depending on the size of the pressing force. When the pressing force is large, the thickness of the packaging area 3012 is small, and the force to open the packaging area is relatively large; when the pressing force is small, the packaging area The larger the thickness, the relatively less force to open the encapsulation area.
  • the encapsulation structure 3010 includes at least one level of encapsulation areas with predetermined lengths. As shown in FIG. 4 , the encapsulation structure 3010 around the buffer 300 has three levels of encapsulation areas with lengths L2, L4 and L6. Each encapsulation area has a predetermined length. When the encapsulation area is opened to form upper and lower layers of encapsulation material, the encapsulation area forms a buffer space with a certain volume. When the compression pressure of the expansion of the cell 200 in the accommodation chamber continues to increase and exceeds the pressure threshold of the first packaging area, the first-level packaging area is opened and communicated with the accommodation chamber, increasing the volume of the accommodation chamber and releasing the pressure of the chamber.
  • the second-level packaging area is opened to continue to increase the volume of the accommodation chamber and relieve the pressure in the accommodation chamber.
  • the length and quantity of the encapsulation area can also be set according to actual needs.
  • the buffer member 300 provided includes a secondary encapsulation area, and the secondary encapsulation area can continuously increase the pressure in the accommodation cavity. Larger cases are opened separately.
  • the overall thickness of the buffer member will become thinner, so as to provide space for the expansion of the electric core.
  • the buffer member 300 is squeezed due to the expansion of the electric core 200, and when the extrusion force reaches a predetermined pressure value, the packaging area with a predetermined length on the outer periphery of the containing cavity is opened, increasing the volume of the containing cavity, and transferring the expanded pressure to the peripheral area of the housing cavity.
  • the packaging area of the buffer can be set according to the internal space of the housing 100, so that the space at both ends in the height direction of the battery cell is not so much expanded, and the redundant space at the tab part in the height direction of the battery cell can also be fully utilized. .
  • the cushioning member 300 can be made of flexible material. Due to the strong deformability of the accommodation chamber brought by the flexible material, the packaging structure of the buffering member does not need to strictly match the void space that exists after the cell expands. With a corresponding arrangement, these voids can be filled using pressure and the deformability of the flexible material.
  • the buffer member corresponding to the battery cell by arranging the buffer member corresponding to the battery cell, on the one hand, the initial gap between the battery cell and the casing can be effectively filled when the battery cell does not expand.
  • the gap avoids the loosening of the winding structure of the battery core and the phenomenon of lithium separation in the electrode sheet; on the other hand, when the battery core expands during use, the buffer member is squeezed by the expansion of the battery core Deformation can occur.
  • the deformation of the buffer is small, and as the expansion pressure of the electric core gradually increases to a certain extent, the packaging area of the buffer gradually Open, the space of the accommodating cavity becomes larger gradually, and the deformation of the buffer member also gradually becomes larger, thereby relieving the pressure brought by the expansion of the battery cell, and realizing that the battery cell and the shell
  • the gap between the bodies can be filled by the buffer, which reduces the influence of cell expansion on the pole piece and avoids the phenomenon of lithium precipitation.
  • the buffer member is disposed corresponding to the middle side wall portion in the height direction of the cell.
  • FIG. 3 it is a cross-sectional view of a battery cell in the direction of the cell height (Y axis).
  • the side wall of the cell refers to the outer wall of the cell 200 parallel to the height direction (Y axis), including the cell thickness direction.
  • a tab 205 is provided in the height direction (Y axis) of the battery core.
  • the buffer can be placed on any part of the cell to fill the gap and relieve the The expansion force caused by the expansion of the battery core.
  • the buffer member 300 is arranged corresponding to the middle side wall part of the battery cell 200, and the middle side wall part is the middle area between the two ends of the battery cell in the height direction, including The side wall in the thickness direction (X-axis direction) of the cell and the side wall in the width direction (Z-axis direction) of the cell are defined.
  • the corresponding arrangement means that the buffer member 300 and the battery cell 200 are arranged in the casing 100 , and at least part of the buffer member 300 is attached to the middle side wall of the battery cell 200 .
  • the buffer member 300 is attached to the first side wall 203 of the battery cell, and the buffer member 300 is located at the middle side wall portion of the battery cell 200 .
  • the expansion force of the battery cell 200 can be alleviated to the greatest extent.
  • the buffer member 300 may be disposed between the battery cell 200 and the side wall of the casing 100 . Continuing to refer to FIG. 3 , the buffer member 300 is disposed between the first side wall 203 of the battery cell and the side wall of the casing 100 . In some embodiments, as shown in FIG.
  • the battery cell includes two battery cells 200, and the buffer member 300 is arranged between each battery cell 200 and the side wall of the casing 100; when there is only one
  • a buffer member can be provided at a position corresponding to one side wall of the battery cell, and the other side of the battery cell depends on the side wall of the housing, or it can be placed between the side walls of the battery cell 200 and the side wall of the housing 100. Buffer pieces are respectively arranged between the walls.
  • the buffer member 300 may also be arranged between adjacent battery cells 200, as shown in FIG. 5 , which shows another structure of a battery cell 1000.
  • the battery cell 1000 includes a casing 100 , a cell 200 and a buffer 300 , the cell 200 and the buffer 300 are arranged in the casing, and the buffer 300 is arranged between adjacent cells 200 , one side of the battery cell 200 is set corresponding to the side wall of the casing 100 , and the other side is set corresponding to the buffer member 300 .
  • the buffer member 300 and the battery cell 200 can also be arranged in a mixed manner, that is, the buffer member can be arranged between the battery cell and the side wall of the casing and at the same time.
  • the buffer member can be arranged between the battery cell and the side wall of the casing and at the same time.
  • buffers can also be provided between the cells, In this way, in the battery cell structure shown in FIG. 3 , there are two battery cells and three buffer members that cooperate with each other.
  • the mixed arrangement provided by this embodiment can solve the problem of expansion of each battery cell to the greatest extent.
  • the packaging structure of the buffer member 300 is located at one end or both ends of the buffer member 300 along the cell height direction.
  • tabs 205 are provided in the height direction (Y-axis direction) of the cell, and there is a gap between the tabs 205 and the casing 100 .
  • the packaging structure of the buffer member 300 is arranged at one or both ends of the buffer member 300 along the height direction of the cell.
  • the pressure caused by the expansion of the cell can be relieved; It is beneficial for the packaging structure of the buffer to expand to the gap in the height direction of the battery cell, fill the gap in the height direction of the battery cell, and avoid lithium deposition in the battery cell.
  • an end cover 400 is provided on the housing 100 at a position corresponding to the tab 205.
  • the end cover 400 is also provided with a A pressure relief mechanism that releases internal pressure when the internal pressure or temperature of the body reaches a threshold.
  • Figure 6a and Figure 6b show a schematic diagram of the arrangement of the packaging structure on the buffer, in Figure 6a, the packaging structure 3210 is located at both ends of the buffer 320 in the height direction, when the buffer and the battery When matching, when the height direction of the buffer member is consistent with the height direction of the battery core, the packaging structure 3210 is located at both ends of the buffer member 320 along the height direction of the battery core.
  • FIG. 6b shows another way in which the encapsulation structure is arranged on the buffer, and the encapsulation structure 3210 can also be arranged only at one end in the height direction of the buffer 320, as shown in Figure 6b, the buffer One end of the component is provided with a packaging structure, and the other end is the outer wall of the housing cavity.
  • the housing cavity When the buffer 320 is squeezed by the expansion force of the battery cell, the housing cavity will press the packaging structure toward one end of the buffer in the height direction.
  • One end of the packaging structure in the height direction of the buffer is gradually split, on the one hand to release space for the expansion of the battery core, and on the other hand to gradually fill the gap at one end in the height direction of the battery core.
  • the packaging structure by arranging the packaging structure at one or both ends in the height direction of the battery cell, on the one hand, it can relieve the pressure caused by the expansion of the battery cell, and on the other hand, it is beneficial for the packaging structure of the buffer to move toward the height direction of the battery cell.
  • the gap expands, fills the gap in the height direction of the battery cell, and avoids the phenomenon of lithium precipitation in the battery cell.
  • some embodiments of the present application also propose to arrange the packaging structure at one or both ends of the buffer member in the width direction, as shown in Figure 6c and Figure 6d Show.
  • the packaging structure 3210 is located at both ends of the buffer member in the width direction.
  • the height direction of the buffer member is the same as the height direction of the electric core.
  • the encapsulation structure 3210 is located at both ends of the buffer along the width direction of the cell.
  • the accommodating cavity will press the encapsulation structure toward both ends of the buffer member in the width direction, and the encapsulation structure is gradually opened to gradually release the space.
  • the encapsulation structure 3210 can also be provided only at one end of the buffer member 320 in the width direction, as shown in FIG. 6d, and the other end is the outer wall of the housing cavity. When squeezed, the accommodating cavity will squeeze the packaging structure toward one end of the buffer in the width direction, and gradually release the space.
  • some embodiments of the present application also propose to arrange the packaging structure at one or both ends of the buffer member in the height direction and width direction, as shown in the figure 6e and Figure 6f.
  • the encapsulation structure 3210 and the encapsulation structure 3211 are respectively located at both ends of the buffer member in the width direction and at both ends of the buffer member in the height direction.
  • the encapsulation structure 3210 is located at both ends of the buffer along the width direction of the electric core
  • the encapsulation structure 3211 is located at both ends of the buffer along the electric core. Both ends of the core height direction.
  • the packaging structure can At the same time, the space is released in four directions, and the space can be quickly released under the extrusion of the expansion force of the battery cell.
  • the encapsulation structure 3210 may also be provided only at one end of the buffer member 320 in the width direction, and the encapsulation structure 3211 may also be provided only at one end of the buffer member 320 in the height direction, as shown in FIG. 6f, When the buffer member 320 is squeezed by the expansion force of the electric core, the accommodating cavity will press the packaging structure toward one end in the width direction and one end in the height direction of the buffer member, and gradually release the space.
  • the above-mentioned embodiments show how the encapsulation structure is arranged on the buffer, and the encapsulation structure is located at one end and/or both ends of the buffer in the height direction and/or width direction.
  • the packaging structure can be set in various ways according to the actual situation, and can also be set in various combinations of positions, all of which cannot depart from the scope of the contents described in the above embodiments of the present application.
  • the height of the containing cavity is 10%-90% of the height of the battery core.
  • the setting of the height of the accommodating cavity can be flexibly set according to the performance of the electric core.
  • the expansion coefficient of the electric core is large, a smaller accommodating cavity can be set, and more packaging structures can be arranged in the rest of the height area, so that the packaging structure can be opened to gradually release a larger space.
  • the packaging structure can be opened to gradually release a larger space. For example: when the expansion force of the battery cell is large, set the height of the accommodation cavity to 10% of the height of the battery cell, and arrange the packaging structure on the remaining height area.
  • the thickness of the buffer will be reduced by about 90%, which can greatly increase the space released for the expansion of the battery; when the expansion force of the battery is small, in order to better fill the initial gap between the battery and the shell, the The height of the containing cavity can be 90% of the height of the battery core.
  • other heights can also be set according to the performance of the battery cell, such as: 50% to 85%, or 60% to 80%. The difference in such a height ratio is small, which better balances the space release requirements and the battery and shell. The need to fill the gaps between bodies.
  • the packaging structure can be arranged in the remaining height area when the height direction is not full, and the arrangement positions of the accommodating cavity and the packaging structure depend on The flexible arrangement of the performance of the specific battery cells makes the setting of the buffer more flexible.
  • the packaging structure includes at least two stages of packaging regions with different packaging strengths, so that as the pressure in the housing chamber increases, the packaging regions are opened step by step, and a buffer space communicating with the housing chamber is gradually formed.
  • Figure 4 it is a schematic diagram of a buffer structure provided by the embodiment of the present application.
  • the packaging structure adopted by the buffer adopts a three-level packaging structure.
  • the buffer can also adopt a second-level or fourth-level packaging structure.
  • Other forms of packaging structures are possible.
  • the buffer member 300 includes a packaging structure 3010, the packaging structure 3010 includes a first packaging area 3012, a second packaging area 3014 and a third packaging area 3016, the first packaging area 3012 is close to the receiving cavity 305, and the electrical
  • the expansion force of the core squeezes the cushioning member, the pressure inside the accommodating cavity causes the first packaging area to crack first, so the sealing layer of the first packaging area is compressed the least and has the weakest strength;
  • the encapsulation strength of the second encapsulation area is increased, and by analogy, the encapsulation strength of the third encapsulation area is the highest, thereby realizing an encapsulation structure in which encapsulation strength presents a gradient change.
  • the packaging strength between different packaging areas has a strength difference of about 1N/mm.
  • the packaging strength of the first packaging area is 1N/mm
  • the packaging strength of the second packaging area is 3N/mm
  • the packaging strength of the third packaging area is 5N/mm
  • the packaging strength of the first packaging area is 1N/mm
  • the packaging strength of the second packaging area is 5N/mm
  • the packaging strength of the third packaging area is 8N/mm; it should be pointed out that different packaging strengths
  • the difference reflects the tolerance to different cell expansion forces. Therefore, in actual use, the packaging strength needs to be set according to the characteristics of the cell and the specific use environment.
  • the embodiment of the present application sets predetermined lengths for different packaging areas.
  • the first The packaging length of the packaging area 3012 is L2
  • the packaging length of the second packaging area is L4
  • the packaging length of the third packaging area is L6.
  • the packaging lengths between the different packaging areas can be the same or different; when the packaging lengths are the same
  • the same space can be released; when the package lengths are different, different spaces can be released at different stages, and the released space can be adjusted.
  • there is no special limitation on the length of the package In actual use, the user can determine it independently according to the characteristics of the battery.
  • the packaging length of the first packaging area can be set smaller; with the use of the battery, the expansion force of the battery gradually increases, and the space occupied by each expansion gradually increases. If is larger, the package length of the second package area and the package length of the third package area can be gradually increased, so as to release a larger space gradually.
  • the pressure of the electric core on the accommodating cavity gradually increases.
  • the first packaging area is first cracked. After the first packaging area is cracked, the space in the accommodating cavity will become larger, and the thickness of the buffer will become thinner; and so on, when the second packaging area and the third packaging area are cracked, the The space released by the buffer will gradually increase.
  • the buffer member When the third packaging area is stretched, the buffer member exhibits the maximum space release state, that is, the buffer member assumes the minimum space occupation state, that is, the space occupied by the buffer member is only the thickness of the aluminum-plastic film,
  • the incompressible thickness is less than or equal to 1mm, and the mass density is less than or equal to 0.5kg/m2, which has very little effect on the volume and weight of the battery.
  • At least two levels of packaging areas are arranged continuously; and/or at least two levels of packaging areas are arranged at intervals, and a buffer zone of predetermined length is provided between adjacent two levels of packaging areas.
  • At least two levels of the packaging areas are arranged at intervals, and two adjacent levels
  • a buffer zone of predetermined length is set between the encapsulation areas.
  • a first buffer zone 3011 with a predetermined length is set between the accommodating cavity 305 and the first packaging area 3012.
  • the first buffer zone 3011 is an unheat-sealed area, and the unheated area refers to the The sealing layers of the cushioning material are only bonded together without heat sealing, so that when the accommodating cavity 305 is squeezed by the expansion force of the electric core, the unheat-sealed aluminum-plastic film will be supported. open to free up more space.
  • a first buffer zone 3011 with a length of L1 is provided between the accommodation cavity 305 and the first packaging area 3012
  • a buffer zone 3011 with a length of L1 is provided between the first packaging area 3012 and the second packaging area 3014
  • a third buffer zone 3015 with a length of L5 is set between the third encapsulation area 3016 and the second encapsulation area 3014, and the above multiple buffer areas divide the encapsulation area 3010 into multiple
  • it can block the heat radiation between different packaging areas, and on the other hand, it can provide more release space for the accommodating cavity.
  • the lengths of the different buffers can be set as required, and can be the same or different.
  • the same space can be released when each buffer is split; when the lengths of the buffers are different, different spaces can be released at different stages, and the released space can be adjusted .
  • the length of the buffer zone there is no special limitation on the length of the buffer zone.
  • the user can determine it independently according to the characteristics of the battery cell.
  • the space occupied by the core after expansion is small, so the length of the first buffer zone can be set smaller; with the use of the battery, the expansion force of the battery gradually increases, and the space occupied by each expansion gradually increases. increase, the length of the second buffer and the length of the third buffer can be gradually increased, so that a larger space can be released gradually.
  • FIG. 7 of the embodiment of the present application the state change process of the buffer member with packaging areas arranged at intervals during use is provided.
  • FIG. 7 it is a schematic diagram of the working state of the buffer when it is pressed by the expansion force of the battery.
  • State 1 is the state of the buffer when it is subjected to a small expansion force of the battery. Both the buffer area and the encapsulation area are in an initial state.
  • the first buffer zone is opened first;
  • the pressure generated by the first encapsulation area is greater than the encapsulation strength of the first encapsulation area, the first encapsulation area and the second buffer zone are opened, and the buffer space formed by them communicates with the accommodating cavity, as shown in Figure 7
  • the thickness of the accommodating cavity becomes significantly thinner and the length becomes longer, thereby releasing more space for the expansion of the battery core.
  • the accommodating cavity When the buffer member is further increased by the expansion force of the electric core, the accommodating cavity further presses the second packaging area, and when the pressure received by the second packaging area is greater than the packaging strength of the second packaging area, then the second packaging area The second packaging area and the third buffer zone are opened, and the buffer space formed by them communicates with the accommodation chamber. As shown in state 3 of FIG. 7 , the thickness of the accommodation chamber becomes thinner and the length of the accommodation chamber further decreases. long, thereby freeing up more space for the expansion of the cell.
  • the sealing strength of the third encapsulation area is set relatively high, and usually will not be opened.
  • the receiving cavity is completely opened, and the two sides of the receiving cavity are completely bonded together.
  • the space it occupies is only the thickness of the aluminum-plastic films on both sides of the accommodating cavity.
  • the sealing layer of the packaging structure 3010 close to the housing cavity 305 has less compression and weak strength
  • the sealing layer of the packaging area farther away from the housing cavity 305 has a large compression volume and high strength, and has greater packaging strength.
  • the strength of the long-side sealing layer may be 1N/mm
  • the strength of the short-side sealing layer may be 5N/mm
  • the packaging strength of the packaging structure may gradually increase from 1N/mm to 5N/mm.
  • the packaging strength needs to be set according to the characteristics of the battery cell and the specific use environment.
  • the packaging strength can be set at 0.1-50 MPa.
  • the encapsulation strength of the trapezoidal encapsulation structure of continuous encapsulation in this embodiment tends to change gradually, so that when the accommodating cavity is gradually increased by the expansion force of the electric core, the encapsulation structure 3010 is cracked little by little.
  • the continuity of the space released by the buffer member 300 is relatively strong, which avoids the sudden change in space caused by the spaced packaging structure when the space is released, and makes the resistance of the buffer member received by the electric core stronger. Stable, greatly improving the service life of the battery cell.
  • the embodiment of the present application in FIG. 9 provides the state change process of the buffer member with continuous arrangement of packaging regions during use.
  • the expansion force of the battery cell gradually increases, and the packaging area is gradually cracked bit by bit under the pressure of the accommodating cavity, from state 1 to state 2 , the thickness of the cushioning member gradually becomes thinner, and the length of the accommodating cavity gradually increases; from state 2 to state N, the accommodating cavity becomes thinner little by little.
  • the trapezoidal packaging structure can well avoid the sudden change of the release space brought by the buffer, not only releasing space for the expansion of the battery core, but also making the pressure of the buffer member on the battery core more continuous , improve the service life of the battery cell.
  • At least two levels of packaging areas are arranged along the height direction of the electric core, and the packaging area farther away from the receiving cavity has greater packaging strength.
  • the at least two-level packaging areas 3010 arranged continuously or at intervals need to be opened respectively.
  • the at least The two-stage packaging area 3010 is arranged along the height direction of the electric core, so that the packaging area 3010 can be opened and expanded along the height direction of the electric core. Further, in order to gradually open the packaging structure, as shown in FIG. 4 and FIG.
  • the sealing layer of the packaging structure 3010 close to the housing cavity 305 has less compression and weak strength.
  • the sealing layer in the farther packaging area has a large amount of compression and high strength, and has greater packaging strength.
  • the pressure in the containing chamber is greater than or equal to the air pressure inside the battery cell. Since the casing provides an initial gap for the expansion of the cell during use, and due to the existence of the gap, the activity space of the cell in the casing will be increased, which will make the winding structure of the cell loose, and then The wrinkling of the positive and negative plates occurs, which leads to the occurrence of the problem of lithium precipitation. Therefore, in the embodiment of the present application, the pressure in the accommodating chamber is set to be greater than or equal to the air pressure inside the battery cell, for example: in the initial state, the battery cell If the air pressure inside the body is 0.1-0.2MPa, the pressure in the housing chamber can be set to 0.1-0.5MPa.
  • the housing chamber Since the pressure in the housing chamber is greater than the air pressure inside the battery cell, the housing chamber will have a certain impact on the battery cell. Pressure, so that the battery cell can also maintain a full state when the group margin is low, thereby preventing lithium precipitation caused by electrode sheet wrinkles.
  • the packaging strength of the packaging structure of the buffer is 0.1-50 MPa.
  • the packaging strength must be greater than the pressure of the substance in the containing cavity, and on the other hand, it must be able to split quickly after the expansion force generated by the cell reaches a certain threshold. Due to the pressure in the containing cavity Usually it is 0.1-0.2 MPa, and the pressure when the cell expands needs to be considered, so the package strength is preferably in the range of 0.1-50 MPa.
  • the packaging strength of the far packaging area is 50MPa.
  • the cell is a square cell, and the buffer is arranged at one or both ends of the cell in the thickness direction; and/or the buffer is arranged at one or both ends of the cell in the width direction .
  • the height direction of the cell is defined as the Y-axis direction
  • the thickness of the cell is defined as the X-axis direction
  • the width direction of the cell is defined as the Z-axis direction.
  • the buffer member is arranged at one end or both ends of the battery cell in the thickness direction. As shown in FIG.
  • the battery cell 1000 includes a casing 100 , a first cell 210 , a second cell 220 , a first buffer 310 , a second buffer 320 and an end cap 400 .
  • the first battery cell 210 and the second battery cell 220 have the same structure, and the embodiment of the present application takes the second battery cell 220 as an example for illustration. As shown in FIG.
  • the second cell 220 has a square structure, including a first side wall 2203 of the second cell and a first corner 2205 of the second cell, wherein the first side wall 2203 of the second cell is One end of the cell 200 in the thickness direction (the side wall in the Z-axis direction), and the first corner 2205 of the second cell is one end of the cell 200 in the width direction (the side wall in the X-axis direction) .
  • the first buffer 310 includes a first encapsulation structure 3110
  • the second buffer 320 includes a second encapsulation structure 3210 .
  • the second buffer member 320 is disposed between the inner wall of the casing 100 and the first side wall 2203 of the second cell, and the first buffer member 310 is also disposed on the side of the first cell 210 wall and the inner wall of the housing 100.
  • another buffer member may be provided between the side walls of the first battery cell 210 and the second battery cell 220 to increase the expansion space of the battery cell.
  • FIG. 11 it is a structural diagram of another battery cell proposed in the embodiment of the present application.
  • the buffer member is arranged at one or both ends of the battery cell in the width direction.
  • the second buffer member 320 is arranged on one side of the first corner 2205 of the second battery cell and the first corner 2105 of the second battery cell, and the width of the second buffer member 320 is the same as that of the first corner 2105 of the second battery cell.
  • the sum of the thicknesses of the first cell 210 and the second cell 220 is equal.
  • a first buffer member 310 may also be provided on one side of the other corner of the first cell 210 and the second cell.
  • the packing area of the first buffer member and the second buffer member may be located in the height direction (Y-axis direction) of the battery core, or in the thickness direction (X-axis direction) of the battery core.
  • buffer members can also be provided at one or both ends in the thickness direction of the battery cell, and at one or both ends in the width direction of the battery cell, That is to say, all the side walls around the battery cell are provided with cushioning parts. In this way, the expansion force of the battery cell in all directions can be relieved.
  • the width of the accommodating cavity is 50% to 100% of the battery cell width in the width direction of the battery cell.
  • the first buffer member 310 is respectively arranged at one end or both ends of the first battery cell 210 and the second battery cell 220 in the thickness direction, the width of the battery cell is K2, and the The width of the buffer is K1.
  • the width of the buffer member is the same as the width of the housing cavity, preferably the maximum width of the housing cavity is 100% of the width of the battery cell; it is also possible to adjust the width of the housing cavity to 100% according to the expansion of the battery core Set to 80% of the cell width, leaving proper space on both sides of the cell.
  • the width of the accommodating cavity can also be set to 50% of the width of the electric core. It should be pointed out that the ratio of the width of the accommodating cavity to the width of the electric core can be adjusted depending on the expansion of the electric core, and can be adjusted within the above range according to actual needs.
  • the section of the accommodation chamber in the height direction of the electric core is annular, and continuously surrounds the electric core.
  • various forms of buffers are also provided to adapt to different shapes of cell structures, such as buffers with circular columnar structures, rectangular buffers, and polygonal ring structures.
  • the ring buffer 330 is a ring-shaped columnar structure, which is adapted to a cylindrical battery cell.
  • the ring buffer 330 includes a ring-shaped packaging structure 3310 , the annular packaging structure 3310 is located at one or both ends of the annular buffer 330 along the height direction of the cell.
  • the ring-shaped buffer 330 is set together with the cylindrical cell, the ring-shaped buffer continuously surrounds the cell, and the section of the cavity of the ring-shaped buffer in the height direction of the cell is ring-shaped.
  • the rectangular buffer 340 proposed by the embodiment of the present application is a rectangular ring structure, which is suitable for a square battery.
  • the rectangular buffer 340 includes a packaging structure 3410, and the rectangular The section of the accommodating cavity of the buffer member in the height direction of the electric core is rectangular and continuously surrounds the electric core.
  • the rectangular packaging structure is located at one or both ends of the rectangular buffer member along the height direction of the electric core. When in use, the rectangular buffer 340 wraps around the battery core.
  • the battery cell can be surrounded, and a buffer can be formed around the battery core.
  • the gaps in each position can avoid lithium precipitation caused by the shaking of the battery cell.
  • it can also provide space for the expansion of the battery cell in all directions around the battery cell when the battery cell expands.
  • the material of the cushioning member 300 has an outer protective layer and an inner sealing layer, and the packaging area of the buffering member is formed by heat-sealing the inner sealing layer.
  • the protective layer is located on the outer layer of the buffering member and mainly plays the role of anti-scratch and corrosion resistance. It can be polyester resin, polyamide resin, iron Single or multiple combinations of fluorocarbon and aluminum; the internal sealing layer mainly plays the role of tightly sealing and isolating the communication between internal and external substances, and can be single or multiple combinations of polyolefin, resin and silicone adhesive.
  • the aluminum-plastic film has good elasticity, which can fully release the expansion force during the charging and discharging process, ensure the uniform expansion force in the central area, reduce the polarization difference, and avoid local lithium precipitation or pole piece fracture caused by polarization.
  • an aluminum-plastic film is used as the material for making the buffer. It should be pointed out that other materials can also be used instead of the aluminum-plastic film to make the buffer, as long as the requirements of elasticity and sealing can be met, the present application does not make a limitation here.
  • FIG. 15 shows the forming process of the cushioning member 300 and a cross-sectional view of the cushioning member 300.
  • the cushioning part is formed by pressing the aluminum-plastic film 301, and the aluminum-plastic film 301 is punched by an abrasive tool to form a pit with a certain depth and area at the center, and the punched aluminum-plastic film is heat-sealed During heat sealing, the internal sealing layers are melted and glued together to form the encapsulation area 3010 , and the encapsulation area 3010 seals the cavity to form the accommodating cavity 305 .
  • the inner sealing layer plays a role of sealing the substances in the containing cavity, and the outer protective layer forms protection for the sealing layer.
  • two pressed aluminum-plastic films can be sealed up and down relative to each other to form a buffer; or a piece of punched aluminum-plastic film can be directly folded in half and sealed to form a buffer.
  • at least one packaging structure and accommodating cavity are formed on the outer periphery of the buffer member.
  • the heat sealing process is used as an example to illustrate the formation of the packaging area.
  • other processes can also be used to form the packaging area, such as adhesive bonding, etc., which are not limited here.
  • the accommodating cavity of the buffer member is filled with inert fluid.
  • the accommodating cavity of the buffer in order to enhance the use effect of the buffer, in the embodiment of the present application, can be filled with a deformable inert fluid substance, such as argon , nitrogen, paraffin or silicone oil, etc., in the case of impure liquid filling, the pressure of the containing cavity is not lower than the pressure of the residual space inside the battery core (usually, the pressure inside the battery core is 0.1 ⁇ 0.2MPa); in the case of filling with pure liquid, the accommodating cavity is completely filled.
  • a deformable inert fluid substance such as argon , nitrogen, paraffin or silicone oil, etc.
  • the containing cavity by filling the containing cavity with an inert substance, it avoids the expansion of the containing cavity of the buffer member due to the substance or material contained in itself when the temperature of the battery core rises, thereby avoiding the buffer itself.
  • the expansion squeezes the expansion space of the cell.
  • a battery 2100 is also proposed. As shown in FIG. 16 , the battery may include one or more battery cells 1000 described in the above embodiments, and a bus component 2101 .
  • the bus component 2101 electrically connects the one or more battery cells 1000 in series or in parallel.
  • the one or more battery cells 1000 include at least an electric cell 200 and a buffer member 300.
  • the buffer member 300 adopts the packaging structure mentioned in the above-mentioned embodiment and is arranged corresponding to the side wall of the electric cell 200 for When the battery cell 200 expands, the packaging structure is opened to provide a buffer space for the battery cell to expand.
  • an electric device the electric device includes the battery 2100 proposed in the above embodiments, and the battery is used to provide electric energy for the electric device.
  • the electrical device may be, but not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, and the like.
  • electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric boat toys, electric airplane toys, etc.
  • spacecraft may include airplanes, rockets, space shuttles, spaceships, etc.
  • FIGS. 17 to 19 show a commonly used battery cell structure. In this battery cell structure, no buffer is used to deal with the expansion force.
  • the buffer is arranged on the side wall of the battery cell and the shell. In between, the buffer is packaged with a spaced packaging structure.
  • the buffer is arranged between the side wall of the battery cell and the casing, and the buffer is packaged with a trapezoidal packaging structure that is continuously packaged. .
  • the structure of the battery cell is shown in FIG. 17 , including the battery cell 200 and the casing 100 without a buffer.
  • the LFP positive electrode/negative electrode/separator film is wound into a core by winding, and the core is cold-pressed, followed by lug welding, shell insertion, top cover welding, Baking, liquid injection until the finished cell is placed in the warehouse, and the finished battery
  • the initial fixture force is 1000N; use a constant temperature box at a temperature of 25°C to conduct a 1C/1C cycle retention rate test, and record the expansion force data in real time until the capacity decays to 90%.
  • SOH constant temperature box at a temperature of 25°C to conduct a 1C/1C cycle retention rate test, and record the expansion force data in real time until the capacity decays to 90%.
  • the battery cell is tested with a three-piece aluminum plate fixture and sensor, and the initial fixture force is 1000N; use an incubator at a temperature of 25°C to conduct a 1C/1C cycle retention rate test, and record the expansion force data in real time until the capacity decays to 90% SOH.
  • the battery cell in Figure 19 including the battery cell 200, the casing 100 and the buffer 300, is made of aluminum-plastic film with a thickness of 150um, of which the protective layer is 70um, and the sealing layer is 80um; 200kgf, 3s heat-pressing beveled edge sealing conditions, long side strength 3N/mm, short side strength 10N/mm; the cross-sectional view of the battery cell structure is shown in Figure 19, including the battery cell, buffer and casing;
  • the LFP positive electrode/negative electrode/separator film is wound into a core, and the core is cold-pressed, followed by lug welding, shell insertion, top cover welding, baking, liquid injection until the finished battery cell is lowered, and the size of the finished battery cell 40*200*100mm, the winding core is fully charged with a group margin of 93%, the cell is fully charged with a group margin of 98%, and the rated capacity is 95Ah.
  • the battery cell is tested with three aluminum plate fixtures and sensors, the initial fixture force is 1000N; use a constant temperature box, at a temperature of 25°C, perform a 1C/1C cycle retention rate test, record the expansion force data in real time, until the capacity decays to 90% SOH .
  • Buffer structure expansion force test one none none 8000N test two 2 Secondary Packaging Buffer 5000N test three 2 Keystone Package Buffer 5000N
  • the buffer member corresponding to the battery cell by arranging the buffer member corresponding to the battery cell, on the one hand, the initial gap between the battery cell and the casing can be effectively filled when the battery cell does not expand.
  • the gap avoids the loosening of the winding structure of the battery core and the phenomenon of lithium separation in the electrode sheet; on the other hand, when the battery core expands during use, the buffer member is squeezed by the expansion of the battery core Deformation can occur.
  • the deformation of the buffer is small, and as the expansion pressure of the electric core gradually increases to a certain extent, the packaging area of the buffer gradually Open, the space of the accommodating cavity becomes larger gradually, and the deformation of the buffer member also gradually becomes larger, thereby relieving the pressure brought by the expansion of the battery cell, and realizing that the battery cell and the shell
  • the gap between the bodies can be filled by the buffer, which reduces the influence of cell expansion on the pole piece and avoids the phenomenon of lithium precipitation.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Sealing Battery Cases Or Jackets (AREA)
  • Battery Mounting, Suspending (AREA)

Abstract

本申请公开了一种电池单体(1000)，电池单体(1000)包括壳体(100)、至少一个电芯(200)和缓冲件(300)，至少一个电芯(200)容纳于所述壳体(100)内；缓冲件(300)与所述电芯(100)的侧壁对应设置，所述缓冲件(300)具有容纳腔(305)，所述容纳腔(305)的外周包括至少一个封装结构(3010)，所述封装结构(3010)包括至少一级具有预定长度的封装区域，当所述容纳腔(305)内的压力超过所述封装结构(3010)的封装强度时，所述封装区域打开并形成与所述容纳腔(305)连通的缓冲空间，减小了电芯膨胀带来的影响。

Description

电池单体、电池及用电装置 技术领域
本申请涉及电池领域，具体涉及一种电池单体、电池及用电装置。
背景技术
节能减排是汽车产业可持续发展的关键，电动车辆由于其节能环保的优势成为汽车产业可持续发展的重要组成部分。对于电动车辆而言，电池技术又是关乎其发展的一项重要因素。
本申请发明人在研究中发现，现有的电池在充放电的使用过程中，随着电芯温度的升高以及使用时间的加长，电芯会发生鼓胀，进而挤压电池壳体，给锂电池的使用带来风险。
发明内容
鉴于上述问题，本申请提供一种电池单体、电池及用电装置，用于解决现有技术中存在的上述问题。
第一方面本申请实施例提供了一种电池单体，包括：
壳体；至少一个电芯，容纳于所述壳体内；以及，缓冲件，容纳于所述壳体内，并与所述电芯的侧壁对应设置，所述缓冲件具有容纳腔，所述容纳腔的外周包括至少一个封装结构，所述封装结构包括至少一级具有预定长度的封装区域，当所述容纳腔内的压力超过所述封装结构的封装强度时，所述封装区域打开并形成与所述容纳腔连通的缓冲空间。
通过将缓冲件与所述电芯侧壁对应设置，一方面能够有效填充电芯和壳体之间的初始空隙，避免电芯卷绕结构出现松散现象和析锂现象，另一方面能够在电芯使用过程中发生膨胀时，缓解电芯膨胀带来的压力，减小电芯膨胀对极片的影响。
可选的，所述侧壁包括位于所述电芯高度方向的两个端部中间区域的中间侧壁部分，所述缓冲件与所述中间侧壁部分对应设置。
通过将缓冲件和电芯的中间侧壁部分对应设置，能够为电芯膨胀力最大的部位提供缓冲空间，最大程度的缓解电芯膨胀带来的压力。
可选的，所述缓冲件设置在所述电芯与所述壳体的侧壁之间，和/或，所述缓冲件夹在相邻的所述电芯之间。
通过将缓冲件设置在电芯的不同位置，能够根据电芯的特性最大程度的解决电芯膨胀带来的问题。
可选的，所述封装结构位于所述缓冲件沿所述电芯高度方向上的一端或两端。
此种设置方式能够使封装结构在裂开的过程中，充分利用电芯高度方向上的空间，一方面可以对电芯高度方向上的空间进行填充，另一方面也便于所述缓冲件在电芯膨胀力的作用下向电芯高度方向上裂开。
可选的，在所述电芯的高度方向上，所述容纳腔的高度为所述电芯高度的10～90％。
通过将容纳腔的高度设置成与电芯高度成一定比例，可以在电芯高度方向上的空间内，布置封装结构，使缓冲件的设置更加灵活。
可选的，所述封装结构包括至少两级具有不同封装强度的封装区域，使得随着所述容纳腔内的压力增加，所述封装区域逐级打开，并逐级形成与所述容纳腔连通的缓冲空间。
此种设置方式，可以随着电芯的使用，电芯的膨胀力逐渐增大时，所述封装区域被逐步打开，容纳腔的空间能够随着电芯膨胀力的增大而逐步释放。
可选的，所述至少两级所述封装区域连续布置；和/或，所述至少两级所述封装区域间隔布置，在相邻的两级所述封装区域之间设有预定长度的缓冲区。
通过将封装区域连续布置能够使容纳腔随着电芯膨胀力度增大，逐步释放空间，避免带来空间突变，使所述电芯受到的缓冲件的阻力更加平稳，大大提升了电池单体的使用寿命。将封装区域间隔设置，在封装区域之间设置缓冲区能够调节封装区域释放空间的大小，设置灵活。
可选的，所述至少两级所述封装区域沿所述电芯的高度方向布置，并且距离所述容纳腔较远的所述封装区域具有较大的封装强度。
上述设置能够使所述缓冲件非常容易的向电芯高度方向上逐步扩展，随着电芯膨胀压力的增大，能够逐步释放空间。
可选的，所述容纳腔内的压力大于等于所述电池单体内部的气压。
由于容纳腔内的压力大于电池单体内部的气压，使所述容纳腔对电芯产生一定的压力，从而使所述电池单体在低群裕度时，也能够保持填满状态，从而防止了电极片褶皱导致的析锂。
可选的，所述封装结构的封装强度为0.1～50MPa。
所述封装强度的设置综合考虑了容纳腔内部压强和电芯膨胀带来的压力，一方面能够使容纳腔在初始状态下内部压强能够对电芯产生压力，避免电芯析锂，另一方面能够在电芯膨胀力的挤压下，容纳腔内部的压力能够将封装结构逐步打开。
可选的，所述电芯为方形电芯，并且所述缓冲件设置于所述电芯在厚度方向上的一端或者两端；和/或，所述缓冲件设置于所述电芯在宽度方向上的一端或者两端。
通过将缓冲件灵活设置在电芯的各个方向上，可以缓解电芯在各个方向上的膨胀力。
可选的，当所述缓冲件设置于所述电芯在厚度方向上的一端或两端时，在所述电芯的宽度方向上，所述容纳腔的宽度为所述电芯宽度的50～100％。
通过设定容纳腔的宽度和电芯宽度的比例，可以根据电芯的性能，灵活的为封装结构预留空间，减小电芯膨胀的影响。
可选的，所述容纳腔在所述电芯的高度方向上的截面呈环形，连续地包围所述电芯。
此种设置方式，可以在所述电芯的四周都形成缓冲，一方面避免电芯晃动带来的析锂，另一方面，也能够在电芯发生膨胀时，在电芯的四周各个方向为电芯的膨胀提供空间。
可选的，所述缓冲件的材料具有外部保护层和内部密封层，所述封装区域通过对所述内部密封层进行热封形成。
通过采用对两层结构进行热封的方式，制作简单，密封效果好，容易制成适应于电芯结构的各种缓冲件。
可选的，所述容纳腔内填充有惰性流体。
通过在所述容纳腔内填充惰性物质，避免了所述缓冲件的容纳腔在电 芯温度升高时，由于自身包含的物质或材料带来的膨胀，从而避免了缓冲件自身的膨胀挤压电芯的膨胀空间。
第二方面，本申请提供了一种电池，其包括上述实施例中的电池单体。
第三方面，本申请提供了一种用电装置，其包括上述实施例中的电池，所述电池用于提供电能。
上述说明仅是本申请技术方案的概述，为了能够更清楚了解本申请的技术手段，而可依照说明书的内容予以实施，并且为了让本申请的上述和其它目的、特征和优点能够更明显易懂，以下特举本申请的具体实施方式。
附图说明
通过阅读对下文优选实施方式的详细描述，各种其他的优点和益处对于本领域普通技术人员将变得清楚明了。附图仅用于示出优选实施方式的目的，而并不认为是对本申请的限制。而且在全部附图中，用相同的附图标号表示相同的部件。在附图中：
图1为本申请实施例提供的车辆的结构示意图；
图2位本申请实施例提供的电池的分解结构示意图；
图3为本申请实施例提供的电池单体剖面视图；
图4为本申请实施例提供的缓冲件剖面视图；
图5为本申请实施例提供的另一电池单体剖面视图；
图6a为本申请实施例提供的另一种缓冲件示意图；
图6b为本申请实施例提供的第二种缓冲件示意图；
图6c为本申请实施例提供的第三种缓冲件示意图；
图6d为本申请实施例提供的第四种缓冲件示意图；
图6e为本申请实施例提供的第五种缓冲件示意图；
图6f为本申请实施例提供的第六种缓冲件示意图；
图7为本申请实施例提供的缓冲件的使用状态图；
图8为本申请实施例提供的另一缓冲件的剖面视图；
图9为本申请实施例提供的另一缓冲件的使用状态图；
图10为本申请实施例提供的电池单体爆炸视图；
图11为本申请实施例提供的另一电池单体爆炸视图；
图12为本申请实施例提供的环形缓冲件示意图；
图13为本申请实施例提供的矩形缓冲件示意图。
图14为本申请实施例提供的缓冲件材料结构图；
图15为本申请实施例提供的缓冲件成型示意图；
图16为本申请实施例提供的一种电池结构示意图；
图17为本申请实施例提供的测试一的电池单体剖面视图；
图18为本申请实施例提供的测试二的电池单体剖面视图；
图19为本申请实施例提供的测试三的电池单体剖面视图。
具体实施方式中的附图标号如下：
电池单体1000，壳体100，电芯200，第一端部201，第一侧壁203，极耳205，第一电芯210，第二电芯220，第二电芯第一侧壁2203，第二电芯第一拐角2205，缓冲件300，铝塑膜301，封装结构3010，第一缓冲区3011，第一封装区域3012，第二缓冲区3013，第二封装区域3014，第三缓冲区3015，第三封装区域3016，容纳腔305，第一缓冲件310，第一封装结构3110，第二缓冲件320，第二封装结构3210，环形缓冲件330，环形封装结构3310，端盖400，车辆2000，电池2100，汇流部件2101，控制器2200，马达2300，箱体2110，上箱体2111，下箱体2112。
具体实施方式
下面将结合附图对本申请技术方案的实施例进行详细的描述。以下实施例仅用于更加清楚地说明本申请的技术方案，因此只作为示例，而不能以此来限制本申请的保护范围。
除非另有定义，本文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；本文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。
在本申请实施例的描述中，技术术语“第一”“第二”等仅用于区别不同对象，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量、特定顺序或主次关系。在本申请实施例的描述中，“多个” 的含义是两个以上，除非另有明确具体的限定。
在本文中提及“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。本领域技术人员显式地和隐式地理解的是，本文所描述的实施例可以与其它实施例相结合。
在本申请实施例的描述中，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，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
在本申请实施例的描述中，术语“多个”指的是两个以上(包括两个)，同理，“多组”指的是两组以上(包括两组)，“多片”指的是两片以上(包括两片)。
在本申请实施例的描述中，技术术语“中心”“纵向”“横向”“长度”“宽度”“厚度”“上”“下”“前”“后”“左”“右”“竖直”“水平”“顶”“底”“内”“外”“顺时针”“逆时针”“轴向”“径向”“周向”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请实施例和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请实施例的限制。
在本申请实施例的描述中，除非另有明确的规定和限定，技术术语“安装”“相连”“连接”“固定”等术语应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或成一体；也可以是机械连接，也可以是电连接；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或两个元件的相互作用关系。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实施例中的具体含义。
目前，随着技术的发展，动力电池的应用越来越广泛。动力电池不仅被应用于水力、火力、风力和太阳能电站等储能电源系统，而且还被广泛应用于电动自行车、电动摩托车、电动汽车等电动交通工具，以及军事装备和航空航天等多个领域。随着动力电池应用领域的不断扩大，其市场的 需求量也在不断地扩增。
本申请发明人注意到，随着电池的充放电循环中正极活性物质和负极活性物质嵌入或脱出离子，电芯会发生鼓胀，即正极片和负极片向外膨胀。尤其在电芯的叠片或卷绕的中间区域，膨胀现象更为严重。极片膨胀对电池的性能及使用寿命有不利影响，例如，可能影响电解液对极片的浸润，引起离子传输路径发生改变，带来析锂问题；极片在长期承受较大挤压力时，还可能断裂引发电池内短路风险等等。此外，电池在充放电循环中电解液也会被不断消耗，在电芯使用一定时间后，甚至会发生局部电解液枯竭，电芯鼓胀则会更进一步加剧局部电解液不足的状况。
为了缓解电芯膨胀的问题，可以在电芯内部设置弹力支撑板，通过所述弹力板的弹性收缩，为电芯膨胀留下空间，解决锂离子电池多次充放电循环后正负极极片和隔膜之间接触不紧密而逐渐松散的问题。但对于上述方式，本申请人研究发现，由于弹力支撑板的厚度较大，重量也比较大，会占据电芯内部较多的空间，也会导致电芯的质量增加，从而导致电芯能量密度损失较大。同时，由于弹力支撑板包含大量的金属部件，会导致金属部件在长时间使用过程中存在溶解的风险，溶解后的金属离子会在极片表面析出，而引发隔离膜穿刺等风险，而且，弹力支撑板会导致电芯内部的可压缩空间比较少，从而会导致电芯寿命在使用后期出现膨胀力急剧增大的情况。
基于以上考虑，为了解决电芯使用过程中发生的膨胀力导致电芯性能恶化的问题，本申请发明人经过深入研究，设计了一种新型的电池单体，通过在电池单体的壳体内设置缓冲件，缓冲件会随着电池单体膨胀力的逐步增加，而逐步释放膨胀缓冲空间，很好的解决了电芯使用过程中发生的电芯膨胀导致的电芯性能恶化的问题。
本申请实施例公开的电池单体可以但不限用于车辆、船舶或飞行器等用电装置中。可以使用具备本申请公开的电池单体、电池等组成该用电装置的电源系统，这样，有利于缓解并自动调节电芯膨胀力恶化，提升电池性能的稳定性和电池寿命。
本申请实施例提供一种使用电池作为电源的用电装置，用电装置可以为但不限于手机、平板、笔记本电脑、电动玩具、电动工具、电瓶车、电 动汽车、轮船、航天器等等。其中，电动玩具可以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，航天器可以包括飞机、火箭、航天飞机和宇宙飞船等等。
以下实施例为了方便说明，以本申请一实施例的一种用电装置为车辆2000为例进行说明。
请参照图1，图1为本申请实施例提供的车辆2000的结构示意图。车辆2000可以为燃油汽车、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。车辆2000的内部设置有电池2100，电池2100可以设置在车辆2000的底部或头部或尾部。电池2100可以用于为车辆2000的供电，例如，电池2100可以作为车辆2000的操作电源。车辆2000还可以包括控制器2200和马达2300，控制器2200用来控制电池2100为马达2300供电，例如，用于车辆2000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2100不仅可以作为车辆2000的操作电源，还可以作为车辆2000的驱动电源，代替或部分地代替燃油或天然气为车辆2000提供驱动动力。
请参照图2，图2为本申请实施例提供的电池2100的爆炸图。电池2100包括箱体2110和电池单体1000，电池单体1000容纳于箱体2110内。其中，箱体2110用于为电池单体1000提供容纳空间，箱体2110可以采用多种结构。在一些实施例中，箱体2110可以包括上箱体2111和下箱体2112，上箱体2111与下箱体2112相互盖合，上箱体2111和下箱体2112共同限定出用于容纳电池单体1000的容纳空间。下箱体2112可以为一端开口的空心结构，上箱体2111可以为板状结构，上箱体2111盖合于下箱体2112的开口侧，以使上箱体2111与下箱体2112共同限定出容纳空间；上箱体2111和下箱体2112也可以是均为一侧开口的空心结构，上箱体2111的开口侧盖合于下箱体2112的开口侧。当然，上箱体2111和下箱体2112形成的箱体2110可以是多种形状，比如，圆柱体、长方体等。
本申请实施例所提到的电池2100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2100可以包括电池模块或电池包等。电池单体1000可以是多个，多个电 池单体1000之间可串联或并联或混联，混联是指多个电池单体1000中既有串联又有并联。多个电池单体1000之间可直接串联或并联或混联在一起，再将多个电池单体1000构成的整体容纳于箱体2110内；当然，也可以是多个电池单体1000先串联或并联或混联组成电池模块形式的电池2100，多个电池模块再串联或并联或混联形成一个整体，并容纳于箱体2110内。电池2100还可以包括其他结构，例如，该电池2100还可以包括汇流部件，用于实现多个电池单体1000之间的电连接。
其中，每个电池单体1000可以为锂离子二次电池、锂离子一次电池、锂硫电池、钠锂离子电池或镁离子电池，但不局限于此。电池单体1000可呈圆柱体、扁平体、长方体或其它形状等。
为了进一步说明本申请实施例提供的电池单体，请参照图3，为了便于说明，本申请实施例中，将电芯的高度方向定义为Y轴方向，电芯的厚度定义为X轴方向，电芯的宽度方向定义为Z轴方向，图3为本申请一些实施例提供的电池单体1000在Y轴方向的剖面视图。电池单体1000是指组成电池的最小独立单元。如图3，电池单体1000包括有壳体100、电芯200、端盖400以及其他的功能性部件。
端盖400是指盖合于壳体100的开口处以将电池单体的内部环境隔绝于外部环境的部件。不限地，端盖400的形状可以与壳体100的形状相适应。可选地，端盖400可以由具有一定硬度和强度的材质(如铝合金)制成，这样，端盖在受挤压碰撞时就不易发生形变，使电池单体能够具备更高的结构强度，安全性能也可以有所提高。端盖上可以设置有如电极端子等的功能性部件。电极端子可以用于与电芯电连接，以用于输出或输入电池单体的电能。在一些实施例中，端盖上还可以设置有用于在电池单体的内部压力或温度达到阈值时泄放内部压力的泄压机构。端盖的材质也可以是多种的，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。在一些实施例中，在端盖的内侧还可以设置有绝缘件，绝缘件可以用于隔离壳体内的电连接部件与端盖，以降低短路的风险。示例性的，绝缘件可以是塑料、橡胶等。
壳体100是用于配合端盖400以形成电池单体的内部环境的组件，其中，形成的内部环境可以用于容纳电芯、电解液以及其他部件。壳体100 和端盖400可以是独立的部件，可以在壳体100上设置开口，通过在开口处使端盖盖合开口以形成电池单体的内部环境。不限地，也可以使端盖和壳体一体化，具体地，端盖和壳体可以在其他部件入壳前先形成一个共同的连接面，当需要封装壳体的内部时，再使端盖盖合壳体。壳体可以是多种形状和多种尺寸的，例如长方体形、圆柱体形、六棱柱形等。具体地，壳体的形状可以根据电芯组件的具体形状和尺寸大小来确定。壳体的材质可以是多种，比如，铜、铁、铝、不锈钢、铝合金、塑胶等，本申请实施例对此不作特殊限制。
电芯200是电池单体1000中发生电化学反应的部件。壳体内可以包含一个或更多个电芯。电芯主要由正极片和负极片卷绕或层叠放置形成，并且通常在正极片与负极片之间设有隔膜。
正极片和负极片具有活性物质的部分构成电芯组件的主体部，正极片和负极片不具有活性物质的部分各自构成极耳。正极极耳和负极极耳可以共同位于主体部的一端或是分别位于主体部的两端。在电池的充放电过程中，正极活性物质和负极活性物质与电解液发生反应，极耳连接电极端子以形成电流回路。
如图3和图4所示，本申请实施例提供了一种电池单体1000，包括壳体100以及至少一个电芯200。至少一个电芯200容纳于壳体100内。电池单体1000还包括缓冲件300。缓冲件300容纳于壳体100内，与所述电芯200的侧壁对应设置。缓冲件300具有容纳腔305，容纳腔305的外周包括至少一个封装结构3010。封装结构3010包括至少一级具有预定长度的封装区域3012，当容纳腔305内的压力超过封装结构3010的封装强度时，所述封装区域3012打开并形成与所述容纳腔305连通的缓冲空间。
缓冲件300容纳于壳体100内，为内部设置有容纳腔305，外周封闭的腔体结构。缓冲件300可以为袋型结构，所述袋形结构可以为将一片柔性材料对折后封边形成，也可以为将两片柔性材料相对设置后封边形成。
缓冲件300和电芯200的第一侧壁203对应设置，填充壳体100与电芯100的第一侧壁203之间的空隙。本申请中，壳体100为电芯200在使用过程中的膨胀提供了初始孔隙，但由于该初始孔隙的存在，将加大电芯200在壳体100内的活动空间，使得电芯200的卷绕结构出现松散的现象， 进而出现正负极片的皱褶现象，导致析锂问题的出现。本申请实施例的电池单体1000结构，在壳体100内设置缓冲件300，可以有效地填满该空隙，可以避免电极片的析锂问题的出现。
缓冲件300的容纳腔305的外周包括至少一个封装结构3010，封装结构3010用于将容纳腔密封。可以在容纳腔305的外周设置一个封装结构3010，以便在所述电芯200随着电池的使用时间的增加而发生膨胀时，所述容纳腔305能够随着所述电芯200的膨胀而逐渐增大体积。也可以在容纳腔305的外周设置多个封装结构3010，增大的体积部分可以视电池单体的壳体100内部空间布局而设置，以可以充分利用这些内部空隙而缓解电池单体100膨胀的压力。
封装区域3012为将缓冲件300的外周的封装材料压制成一体的结构区域，该封装区域的封装材料被压制成一层整体材料后，并不能形成容纳腔。封装区域3012可以视压制的力的大小形成不同的厚度，当压制的力较大时，封装区域3012的厚度较小，则打开封装区域的力相对较大；当压制的力较小时，封装区域的厚度较大，则打开封装区域的力相对较小。
封装结构3010包括至少一级具有预定长度的封装区域，如图4所示，缓冲件300外周的封装结构3010具有长度为L2、L4以及L6的三级封装区域。每个封装区域具有预定的长度，当该封装区域被打开，形成上下两层的封装材料，该封装区域就形成了具有一定体积的缓冲空间。当容纳腔受电芯200膨胀的挤压的压力持续增大时，超过第一封装区域的压制压力阈值时，第一级封装区域打开后，与容纳腔连通，增加了容纳腔的体积，释放了容纳腔的压力。当容纳腔受电芯200膨胀的挤压的压力持续增大时，超过第二级封装区域的压制压力阈值时，第二级封装区域打开，为容纳腔继续增大体积，缓解容纳腔的压力。所述封装区域的长度和数量也可以根据实际需要进行设置，比如电池单体1000的壳体100内，设置的缓冲件300包括二级封装区域，二级封装区域可在容纳腔内压力持续增大的情况下分别打开。
当所述封装区域3010被打开并与容纳腔305相连通时，所述缓冲件的整体厚度会变薄，从而为所述电芯的膨胀提供空间。缓冲件300由于电芯200膨胀导致容纳腔受到挤压，当挤压力达到预定压力值时，容纳腔外 周的具有预定长度的封装区域被打开，增加了容纳腔的体积，将膨胀的压力转移到了容纳腔的外周区域。而缓冲件的封装区域，可以视壳体100内部空间而设置，这样可以充分利用电芯高度方向两端膨胀程度没那么多的空间，也可以充分利用电芯高度方向极耳部分的冗余空间。所述缓冲件300可以采用柔性材料制成，由于柔性材料带来的容纳腔的较强的可变形性，因此所述缓冲件的封装结构并不需要严格与电芯膨胀后所存在的空隙空间对应设置，可以利用压力和柔性材料的变形能力填充这些空隙。
因此，综上所述，本申请实施例通过将所述缓冲件与所述电芯对应设置，一方面在能够在电芯未发生膨胀时，能够有效填满电芯与壳体之间的初始空隙，避免了电芯卷绕结构出现松散现象，避免了电极片析锂现象的出现；另一方面，当电芯在使用过程中发生膨胀时，所述缓冲件受到电芯膨胀的挤压时可发生形变，当所述电芯的膨胀压力较小时，所述缓冲件的形变较小，而随着所述电芯膨胀压力的逐步增大到一定程度时，所述缓冲件的封装区域逐步打开，所述容纳腔空间逐渐变大，则所述缓冲件发生的形变也逐渐变大，从而缓解了电芯膨胀带来的压力，实现了在电芯的全生命周期内，电芯和壳体之间的空隙能够被缓冲件所填满，减小了电芯膨胀对极片的影响和避免了析锂现象的出现。
本申请一些实施例中，缓冲件与在电芯高度方向上的中间侧壁部分对应设置。如图3所示，为电池单体在电芯高度(Y轴)方向的剖视图，所述电芯的侧壁指电芯200在与高度方向(Y轴)平行的外壁，包括电芯厚度方向(X轴)上的外壁和电芯宽度方向(Z轴)的外壁。在电芯的高度方向(Y轴)上，设置有极耳205。在电池单体中，电芯侧壁和壳体侧壁之间，以及电芯的极耳与壳体之间都会存在空隙；在电池单体的使用过程中，电芯的膨胀力会在电芯的各个方向上产生，包括电芯的侧壁方向上，以及在电芯的极耳方向上，因此，所述缓冲件可以设置在电芯的任何部位，以填充所述空隙以及缓解所述电芯的膨胀带来的膨胀力。
本申请的发明人在研究过程中，发现电池单体在使用过程中，电芯在其厚度方向上和在其宽度方向上产生的膨胀力最为明显，对电芯的影响也最大。在本申请实施例中，将所述缓冲件300与所述电芯200的中间侧壁部分对应设置，所述中间侧壁部分为所述电芯高度方向的两个端部的中间 区域，包括了所述电芯厚度方向(X轴方向)的侧壁以及所述电芯宽度方向(Z轴方向)的侧壁。其中，所述对应设置是指所述缓冲件300与电芯200设置在壳体100内，并至少部分缓冲件300与电芯200的中间侧壁相贴合。如图3所示，所述缓冲件300与所述电芯的第一侧壁203相贴合，所述缓冲件300位于所述电芯200的中间侧壁部分。本申请实施例中，通过将所述缓冲件300与所述电芯200的中间侧壁部分对应设置，能够最大程度缓解电芯200的膨胀力。
根据本申请提供的一些实施例，所述缓冲件300可以设置在所述电芯200与壳体100的侧壁之间。继续参考图3，所述缓冲件300设置在所述电芯的第一侧壁203与所述壳体100的侧壁之间。在一些实施例中，如图3所示，所述电池单体中包括两个电芯200，所述缓冲件300设置在每个电芯200与壳体100的侧壁之间；当只有一个电芯时，可以在电芯的一侧侧壁对应的位置设置缓冲件，电芯的另一侧和壳体侧壁相依靠，也可以在电芯200的两侧侧壁与壳体100侧壁之间分别设置缓冲件。
根据本申请提供的一些实施例，可选的，所述缓冲件300还可以设置在相邻的电芯200之间，如图5所示，示出了另一种电池单体1000的结构，所述电池单体1000包括壳体100、电芯200和缓冲件300，所述电芯200和缓冲件300设置在所述壳体内，所述缓冲件300设置在相邻的电芯200之间，所述电芯200一侧与壳体100侧壁对应设置，另一侧与缓冲件300对应设置。采用图5所示的电池单体结构，当所述电芯发生膨胀时，所述电芯会向所述缓冲件一侧膨出，进而从两侧挤压所述缓冲件，所述缓冲件通过逐步打开封装区域，为电芯的膨胀提供缓冲空间，所述电池单体占用的空间比较小，电池单体的群裕度会比较高。
根据一些实施例，可选的，所述缓冲件300和所述电芯200还可以采用混合设置的方式，即所述缓冲件可以同时设置在电芯与壳体的侧壁之间和设置在相邻的电芯之间，如图3所示的电池单体结构，除了在电芯侧壁和壳体侧壁之间分别设置有缓冲件外，还可以在电芯之间设置缓冲件，这样在图3的电池单体结构中，就存在两个电芯和三个缓冲件相互配合。当所述电池单体内存在多个电芯时，本实施例提供的所述混合设置的方式，能够最大程度上解决各电芯的膨胀的问题。
根据本申请提出的一些实施例，缓冲件300的封装结构位于缓冲件300沿电芯高度方向上的一端或者两端。如图3所示，电芯的高度方向(Y轴方向)上设置有极耳205，极耳205与壳体100之间存在空隙。将所述缓冲件300的封装结构设置在所述缓冲件300沿电芯高度方向上的一端或两端，在电芯使用过程中，一方面能够缓解电芯膨胀带来的压力，另一方面有利于所述缓冲件的封装结构向电芯高度方向上的空隙扩展，填充电芯高度方向上的空隙，避免电芯发生析锂现象。进一步的，在壳体100上与极耳205对应的位置设置有端盖400，为了释放电芯内部的压力，在一些电池单体结构中，所述端盖400上还设置有用于在电池单体的内部压力或温度达到阈值时泄放内部压力的泄压机构。通过将缓冲件300的封装结构设置于缓冲件300沿电芯高度方向上的一端或者两端，可以在所述缓冲件受到所述电芯的膨胀力足够大时，所有封装结构均被打开的情况下，所述容纳腔内的惰性物质能够通过端盖上的泄压机构方便的将压力排出，减小电芯膨胀带来的影响。
图6a和图6b示出了封装结构在所述缓冲件上的设置示意图，在图6a中，所述封装结构3210位于所述缓冲件320高度方向的两端，当所述缓冲件与电芯相适配设置时，缓冲件的高度方向与所述电芯的高度方向相一致时，所述封装结构3210位于所述缓冲件320沿电芯高度方向的两端。电芯在使用过程中，当所述缓冲件320受到电芯的膨胀力的挤压时，容纳腔将向缓冲件的高度方向的两端挤压所述封装结构，一方面为电芯的膨胀释放空间，另一方面向电芯高度方向上的空隙扩展，填充电芯高度方向上的空隙，避免电芯发生析锂现象。图6b示出了封装结构在所述缓冲件上设置的另一种方式，所述封装结构3210也可以只设置在所述缓冲件320高度方向上的一端，如图6b所示，所述缓冲件一端设置有封装结构，另一端为容纳腔的外壁，当所述缓冲件320受到电芯的膨胀力的挤压时，容纳腔将向缓冲件的高度方向的一端挤压所述封装结构，所述封装结构在缓冲件的高度方向上的一端逐渐裂开，一方面为电芯的膨胀释放空间，另一方面逐渐填充电芯高度方向上的一端的空隙。
上述实施例通过将封装结构设置在电芯高度方向上的一端或两端，一方面能够缓解电芯膨胀带来的压力，另一方面有利于所述缓冲件的封装结 构向电芯高度方向上的空隙扩展，填充电芯高度方向上的空隙，避免电芯发生析锂现象。
可选的，适配于不同的电池单体结构，本申请一些实施例还提出了将所述封装结构设置在所述缓冲件的宽度方向上的一端或两端，如图6c和图6d所示。
如图6c所示，所述封装结构3210位于所述缓冲件宽度方向的两端，当所述缓冲件320与电芯相适配设置时，缓冲件的高度方向与所述电芯的高度方向相一致时，所述封装结构3210位于所述缓冲件沿电芯宽度方向的两端。当所述缓冲件320受到电芯的膨胀力的挤压时，容纳腔将向缓冲件的宽度方向的两端挤压所述封装结构，所述封装结构被逐步打开，并逐渐释放空间。当然，所述封装结构3210也可以只设置在所述缓冲件320宽度方向上的一端，如图6d所示，另一端为容纳腔的外壁，当所述缓冲件320受到电芯的膨胀力的挤压时，容纳腔将向缓冲件的宽度方向的一端挤压所述封装结构，并逐渐释放空间。
可选的，适配于不同的电池单体结构，本申请一些实施例还提出了将所述封装结构分别设置在所述缓冲件的高度方向上和宽度方向上的一端或两端，如图6e和图6f所示。
如图6e所示，所述封装结构3210和封装结构3211分别位于所述缓冲件宽度方向的两端和所述缓冲件高度方向的两端，当所述缓冲件320与电芯相适配设置时，缓冲件的高度方向与所述电芯的高度方向相一致时，所述封装结构3210位于所述缓冲件沿电芯宽度方向的两端，所述封装结构3211位于所述缓冲件沿电芯高度方向的两端。当所述缓冲件320受到电芯的膨胀力的挤压时，容纳腔将向缓冲件的宽度方向和高度方向的两端同时挤压所述封装结构，通过这种方式，所述封装结构可以同时在四个方向上释放空间，能够在电芯膨胀力的挤压下，快速释放空间。当然，所述封装结构3210也可以只设置在所述缓冲件320宽度方向上的一端，所述封装结构3211也可以只设置在所述缓冲件320高度方向上的一端，如图6f所示，当所述缓冲件320受到电芯的膨胀力的挤压时，容纳腔将向缓冲件的宽度方向的一端和高度方向的一端挤压所述封装结构，并逐渐释放空间。
上述实施例示出了封装结构在缓冲件上的设置方式，所述封装结构位 于所述缓冲件的高度方向和/或宽度方向上的一端和/或两端。在实际应用过程中，所述封装结构可以根据实际进行多种方式的设置，也可以采用多种位置组合进行设置，都不能脱离本申请上述实施例描述的内容的范围。
根据本申请提出的一些实施例，在电芯的高度方向，容纳腔的高度为电芯高度的10％～90％。所述容纳腔的高度的设置可以根据电芯的性能灵活设置，当电芯的膨胀系数较大时，可以设置较小的容纳腔，在其余高度区域上布置较多的封装结构，这样可以使所述缓冲件的容纳腔在受到电芯膨胀力的挤压时，能够打开封装结构逐步释放较大的空间。比如：当电芯膨胀力较大时，设置容纳腔的高度为电芯高度的10％，剩余的高度区域上布置封装结构，当电芯受到膨胀力的挤压时，封装区域打开后，所述缓冲件的厚度将减少90％左右，能够为电芯膨胀释放的空间大大增加；当电芯膨胀力较小时，为了更好的对电芯和壳体之间的初始空隙进行填充，所述容纳腔的高度可以为电芯高度的90％。当然也可以根据电芯的性能设置其他的高度，比如：50％～85％，或者60％～80％，这样的高度比例相差较小，较好的平衡了空间释放需求和对电芯和壳体之间空隙进行填充的需求。
因此，上述实施例方式通过将容纳腔的高度设置成与电芯高度方向成一定比例，能够在高度方向并没有填充满时，在其余高度区域布置封装结构，容纳腔和封装结构的布置位置视具体电芯的性能灵活布置，使缓冲件的设置更加灵活。
根据本申请提出的一些实施例，封装结构包括至少两级具有不同封装强度的封装区域，使得随着容纳腔内的压力增加，封装区域逐级打开，并逐级形成与容纳腔连通的缓冲空间。如图4所示，为本申请实施例提供的一种缓冲件结构的示意图，所述缓冲件采用的封装结构采用三级封装结构，当然，所述缓冲件也可以采用二级或者四级等其他形式的封装结构。
所述缓冲件300包括封装结构3010，所述封装结构3010包括第一封装区域3012、第二封装区域3014和第三封装区域3016，所述第一封装区域3012靠近所述容纳腔305，在电芯的膨胀力挤压所述缓冲件时，所述容纳腔内部的压力使所述第一封装区域首先裂开，因此所述第一封装区域的密封层被压缩量最少，强度最弱；第二封装区域的相较于第一封装区域，其封装强度增加，依次类推，第三封装区域的封装强度最高，从而实现了 封装强度呈现梯度变化的封装结构。不同封装区域之间的封装强度大约有1N/mm的强度差异，例如第一封装区域的封装强度为1N/mm，第二封装区域的封装强度为3N/mm，第三封装区域的封装强度为5N/mm；或者第一封装区域的封装强度为1N/mm，第二封装区域的封装强度为5N/mm，第三封装区域的封装强度为8N/mm；需要指出的是，不同的封装强度差异体现出对不同的电芯膨胀力的容忍度，因此，在实际使用中，所述封装强度需要根据电芯的特性和具体的使用环境进行设定。
进一步的，如图4所示，为了使所述密封区域在裂开时可以释放不同的空间，则本申请实施例为不同的封装区域设定预定的长度，如图4中，所述第一封装区域3012的封装长度为L2、第二封装区域的封装长度为L4以及第三封装区域的封装长度为L6，所述不同封装区域之间的封装长度可以相同，也可以不同；当封装长度相同时，则每个封装区域裂开时，都能释放相同的空间；当封装长度不同时，则可以在不同阶段释放不同的空间，能够对释放空间进行调整。在本申请中，并不对封装长度进行特殊的限定，在实际的使用中，使用者可以根据电芯的特性自主进行确定，比如：在电芯使用的初期，其膨胀力较小，电芯膨胀后所占用的空间较小，则可以将第一封装区域的封装长度设置的较小一些；随着电芯的使用，电芯的膨胀力逐渐增大，每次膨胀时所占用的空间逐渐增大，则可以将第二封装区域的封装长度和第三封装区域的封装长度逐渐增加，以便能逐渐释放较大的空间。
随着所述电芯的膨胀力逐步增大时，所述容纳腔受到电芯的压力逐渐增大，当压力大于所述第一封装区域的封装强度时，则所述第一封装区域首先裂开，第一封装区域裂开后，所述容纳腔内的空间会变大，所述缓冲件的厚度会变薄；依次类推，当第二封装区域和第三封装区域裂开后，所述缓冲件释放的空间会逐步增大。当第三封装区域被撑开后，所述缓冲件呈现最大空间释放状态，也即所述缓冲件呈最小空间占用状态，即所述缓冲件占用的空间仅为所述铝塑膜的厚度，不可压缩厚度小于等于1mm，质量密度小于等于0.5kg/m2，这对电芯体积和重量的影响非常小。
根据本申请提出的一些实施例，至少两级封装区域连续布置；和/或至少两级封装区域间隔布置，在相邻的两级封装区域之间设有预定长度的缓 冲区。
进一步的，继续参考图4，为了提高所述缓冲件在受到电芯的膨胀力挤压时能够释放的空间，本申请实施例将至少两级所述封装区域间隔布置，在相邻的两级封装区域之间设置有预定长度的缓冲区。如图4所示，在容纳腔305和第一封装区域3012之间设置预定长度的第一缓冲区3011，所述第一缓冲区3011为未热封区域，所述未热封区域指所述缓冲件材料的密封层只是贴合在一起，并没有进行热封，这样，当所述容纳腔305被所述电芯的膨胀力挤压时，所述未热封的铝塑膜会被撑开，从而释放更多的空间。
如图4所示，在所述容纳腔305和第一封装区域3012之间设置有长度为L1的第一缓冲区3011，在所述第一封装区域3012和第二封装区域3014之间设置有长度为L3的第二缓冲区3013，在所述第三封装区域3016和第二封装区域3014之间设置有长度为L5的第三缓冲区3015，上述多个缓冲区将封装区域3010分割成多个封装区域，一方面可以阻隔不同封装区域之间的热辐射，另一方面能够为所述容纳腔提供更多的释放空间。所述不同缓冲区的长度可以根据需要进行设置，可以相同，也可以不同。当所述各缓冲区的长度相同时，则每个缓冲区裂开时，都能释放相同的空间；当缓冲区长度不同时，则可以在不同阶段释放不同的空间，能够对释放空间进行调整。在本申请中，并不对缓冲区的长度进行特殊的限定，在实际的使用中，使用者可以根据电芯的特性自主进行确定，比如：在电芯使用的初期，其膨胀力较小，电芯膨胀后所占用的空间较小，则可以将第一缓冲区的长度设置的较小一些；随着电芯的使用，电芯的膨胀力逐渐增大，每次膨胀时所占用的空间逐渐增大，则可以将第二缓冲区的长度和第三缓冲区的长度逐渐增加，以便能逐渐释放较大的空间。
为了更加准确的描述上述缓冲件在所述电池单体的使用过程中的变化状态，本申请实施例在图7中，提供了采用间隔布置封装区域的缓冲件在使用过程中的状态变化过程。如图7所示，为所述缓冲件在受到电芯的膨胀力压迫时的工作状态示意图，状态1为所述缓冲件在受到所述电芯膨胀力较小时的状态，所述缓冲件的缓冲区域和封装区域都处于初始状态下。当所述缓冲件的容纳腔受到电芯膨胀力的挤压时，由于缓冲区并没有进行 热封，其能够承受的压力最小，所以第一缓冲区首先被打开；当所述容纳腔内对所述第一封装区域产生的压力大于所述第一封装区域的封装强度时，所述第一封装区域和第二缓冲区被打开，其形成的缓冲空间与所述容纳腔连通，如图7的状态2所示，所述容纳腔的厚度明显变薄，长度变长，从而为所述电芯的膨胀释放了更多空间。当所述缓冲件受到电芯膨胀力进一步加大时，所述容纳腔进一步挤压第二封装区域，所述第二封装区域受到的压力大于所述第二封装区域的封装强度时，则第二封装区域和所述第三缓冲区被打开，其形成的缓冲空间与所述容纳腔连通，如图7的状态3所示，所述容纳腔的厚度进一步变薄，容纳腔的长度进一步变长，从而为所述电芯的膨胀释放更多的空间。
通常情况下，所述第三封装区域的密封强度设置的比较大，通常都不会被打开。但是在极端情况下，当所述缓冲件受到的电芯的膨胀力大于第三封装区域的封装强度时，则所述容纳腔被完全打开，所述容纳腔的两侧完全贴合在一起，其占用的空间仅为所述容纳腔两侧铝塑膜的厚度。由此可以看出，通过设置多级封装区域，为所述电芯的膨胀提供了更多的缓冲空间，大大缓解了电芯的膨胀力带来的影响。
本申请实施例中，也可以将至少两级所述封装区域连续布置，具体的如图8所示，所述缓冲件300的封装结构3010呈梯形结构，所述封装结构3010的封装区域连续布置，所述封装结构3010靠近容纳腔305一侧的密封层的压缩量少，强度弱，距所述容纳腔305较远的封装区域的密封层压缩量大，强度高，具有较大的封装强度。比如：所述长边密封层的强度可以为1N/mm，短边密封层强度为5N/mm，所述封装结构的封装强度从1N/mm逐渐增大到5N/mm。在实际使用中，所述封装强度需要根据电芯的特性和具体的使用环境进行设定，优选的，可以将所述封装强度设定为0.1～50MPa。本实施例中的连续封装的梯形封装结构的封装强度呈逐渐变化的趋势，从而使所述容纳腔在受到电芯的膨胀力逐渐增大时，所述封装结构3010呈一点一点裂开的状态，使所述缓冲件300释放的空间的连续性比较强，避免了所述间隔设置的封装结构在释放空间时，带来的空间突变，使所述电芯受到的缓冲件的阻力更加平稳，大大提升了电池单体的使用寿命。
为了更加准确的描述上述缓冲件在所述电池单体的使用过程中的变化状态，本申请实施例在图9中，提供了采用连续布置封装区域的缓冲件在使用过程中的状态变化过程。如图9所示，随着电池单体在使用过程中，电芯的膨胀力逐渐变大，封装区域在所述容纳腔的压力下，一点一点逐渐裂开，从状态1到状态2，所述缓冲件的厚度逐渐变薄，容纳腔的长度逐渐变大；从状态2到状态N，所述容纳腔一点一点的变薄。由于所述封装区域是逐渐裂开的，避免了一次释放过多的缓冲空间时，导致的电芯与缓冲件之间会存在空隙，造成电芯的晃动等情况的发生，采用连续布置封装区域的梯形封装结构，可以很好地避免所述缓冲件带来的释放空间的突变，不仅为所述电芯的膨胀释放了空间，而且使所述电芯受到的所述缓冲件的压力比较连续，提高了电池单体的使用寿命。
根据本申请提出的一些实施例，至少两级封装区域沿电芯的高度方向布置，并且距离容纳腔较远的封装区域具有较大的封装强度。如图4和图8所示，当容纳腔305受到电芯膨胀力的挤压时，所述连续布置或者间隔设置的至少两级封装区域3010需要分别被打开，为了方便被打开，所述至少两级封装区域3010沿电芯高度方向布置，使封装区域3010能够沿电芯高度方向进行打开和扩展空间。进一步的，为了使所述封装结构被逐步打开，如图4和图8所示，所述封装结构3010靠近容纳腔305一侧的密封层的压缩量少，强度弱，距所述容纳腔305较远的封装区域的密封层压缩量大，强度高，具有较大的封装强度。通过将至少两级封装区域沿电芯的高度方向布置，并且将距离容纳腔较远的封装区域的封装强度设置较大，能够使所述缓冲件非常容易的向电芯高度方向逐步扩展，随着电芯膨胀压力的增大，能够逐步释放空间。
根据本申请提出的一些实施例，容纳腔内的压力大于或等于电池单体内部的气压。由于壳体为电芯在使用过程中的膨胀提供了初始空隙，而由于该空隙的存在，将加大电芯在壳体内的活动空间，会使得电芯的卷绕结构出现松散的现象，进而出现正负极片的褶皱现象，导致析锂问题的出现，因此，本申请实施例将所述容纳腔内的压力设置成大于或者等于电池单体内部的气压，比如：在初始状态下电池单体内部的气压为0.1～0.2MPa，则将容纳腔内的压力可以设置为0.1～0.5MPa，由于容纳腔内的压力大于电池 单体内部的气压，则所述容纳腔会对电芯产生一定的压力，从而使所述电池单体在低群裕度时，也能够保持填满状态，从而防止了电极片褶皱导致的析锂。
根据本申请提出的一些实施例，所述缓冲件的封装结构的封装强度为0.1～50MPa。所述缓冲件为了能够对所述容纳腔内的物质进行密封，同时，也为了能够使所述电芯在膨胀到一定程度后，所述封装结构能够及时裂开，因此，对所述封装结构的封装强度有严格的要求。一方面所述封装强度要大于所述容纳腔内的物质的压力，另一方面也要在所述电芯产生的膨胀力达到一定阈值后能够快速的裂开，由于所述容纳腔内的压力通常为0.1～0.2MPa，同时需要考虑所述电芯膨胀时的压力，因此所述封装强度的范围优选为0.1～50MPa。同时，由于距离容纳腔较远的封装区域具有较大的封装强度，因此，不同的封装区域的封装强度是不同，比如：距离容纳腔最近的封装区域的封装强度为0.1MPa，距离容纳腔最远的封装区域的封装强度为50MPa。
根据本申请提出的一些实施例，电芯为方形电芯，缓冲件设置于电芯在厚度方向上的一端或者两端；和/或缓冲件设置于电芯在宽度方向上的一端或者两端。如图10所示，为了便于说明，将电芯的高度方向定义为Y轴方向，电芯的厚度定义为X轴方向，电芯的宽度方向定义为Z轴方向。在本申请实施例中，所述缓冲件设置于所述电芯在厚度方向上的一端或者两端。如图10所示，所述电池单体1000包括壳体100、第一电芯210、第二电芯220、第一缓冲件310、第二缓冲件320和端盖400。所述第一电芯210和第二电芯220结构相同，本申请实施例以第二电芯220为例进行说明。如图10所示，所述第二电芯220呈方形结构，包括第二电芯第一侧壁2203和第二电芯第一拐角2205，其中所述第二电芯第一侧壁2203为所述电芯200在厚度方向上的一端(Z轴方向的侧壁)，所述第二电芯第一拐角2205为所述电芯200在宽度方向上的一端(X轴方向的侧壁)。所述第一缓冲件310包括第一封装结构3110，所述第二缓冲件320包括第二封装结构3210。
所述第二缓冲件320设置在所述壳体100内壁与所述第二电芯第一侧壁2203之间，所述第一缓冲件310也同样设置在所述第一电芯210的侧壁 和壳体100内壁之间。当然，也可以在第一电芯210和第二电芯220的侧壁之间再设置一个缓冲件，以增加所述电芯的膨胀空间。通过将所述缓冲件设置在所述电芯在厚度方向上的一端或者两端，可以使所述电芯在使用过程中，在电芯两侧分别提供电芯膨胀的空间。
如图11所示，为本申请实施例提出的另一种电池单体的结构图，在本实施例中，所述缓冲件设置于所述电芯在宽度方向上的一端或者两端。与图10相比，所述第二缓冲件320设置在所述第二电芯第一拐角2205和第二电芯第一拐角2105的一侧，所述第二缓冲件320的宽度与所述第一电芯210和第二电芯220的厚度之和相当。同样的，在所述第一电芯210和第二电芯的另一拐角的一侧，也可以设置有第一缓冲件310。所述第一缓冲件和第二缓冲件的封装区域可以位于所述电芯的高度方向(Y轴方向)，也可以位于所述电芯的厚度方向(X轴方向)上。
进一步的，针对图10和图11中的电池单体，也可以同时在所述电芯的厚度方向上的一端或两端，以及，在电芯的宽度方向的一端或两端设置缓冲件，即相当于在电芯的四周侧壁全部设置有缓冲件，通过这种方式，可以缓解电芯在各个方向上的膨胀力。
根据本申请提出的一些实施例，缓冲件设置于电芯在厚度方向上的一端或者两端时，在电芯的宽度方向上，容纳腔的宽度为电芯宽度的50％～100％。如图10所示，所述第一缓冲件310分别设置在所述第一电芯210和第二电芯220在厚度方向上的一端或两端，所述电芯的宽度为K2，所述缓冲件的宽度为K1，为了更好的使所述缓冲件与所述电芯的侧壁相贴合，通常情况下，当所述缓冲件的封装结构位于所述电芯高度方向的一端或两端时，所述缓冲件的宽度与其容纳腔的宽度相同，优选所述容纳腔的最大宽度为所述电芯宽度100％；也可以根据电芯的膨胀情况，将所述容纳腔的宽度设置为电芯宽度的80％，在电芯的两侧留出适当的空间。同样，当电芯的膨胀系数较小时，也可以将所述容纳腔的宽度设置为电芯宽度的50％。需要指出的是，所述容纳腔的宽度与所述电芯宽度的比例可以视电芯的膨胀情况进行调整，根据实际需要在上述范围内进行调整。
根据本申请提出的一些实施例，所述容纳腔在电芯的高度方向上的截面呈环形，连续地包围电芯。本申请的一些实施例中，还提供了多种形态 的缓冲件，以适配不同形态的电芯结构，比如环形柱状结构的缓冲件、矩形缓冲件和多边形环形结构的缓冲件等等。
如图12所示为本申请实施例提供的环形缓冲件330示意图，所述环形缓冲件330为环形柱状结构，适配于圆柱体形状的电芯，所述环形缓冲件330包括环形封装结构3310，所述环形封装结构3310位于所述环形缓冲件330沿所述电芯高度方向上的一端或者两端。当所述环形缓冲件330与圆柱形电芯设置在一起时，所述环形缓冲件将所述电芯连续的包围，所述环形缓冲件的容纳腔在电芯高度方向的截面成环形。
如图13所示为本申请实施例提出的矩形缓冲件340，所述矩形缓冲件340为矩形环形结构，适配于方形的电芯，所述矩形缓冲件340包括封装结构3410，所述矩形缓冲件的容纳腔在所述电芯的高度方向上的截面呈矩形，连续地包围所述电芯，所述矩形封装结构位于所述矩形缓冲件沿所述电芯高度方向上的一端或者两端，在使用时，所述矩形缓冲件340包裹在所述电芯的四周。
上述实施例通过将所述缓冲件设置成多种环形结构，可以将电芯进行包围，在所述电芯的四周都形成缓冲，一方面可以有效的填充在初始时，电芯与壳体在各个位置的空隙，避免电芯晃动带来的析锂，同时，也能够在电芯发生膨胀时，在电芯的四周各个方向为电芯的膨胀提供空间。
根据本申请提出的一些实施例，所述缓冲件300的材料具有外部保护层和内部密封层，所述缓冲件的封装区域通过对内部密封层进行热封形成。如图14所示，为缓冲件材料的结构示意图，所述保护层位于所述缓冲件的外层，主要起到防刮碰和耐腐蚀的作用，可以是聚酯树脂、聚酰胺树脂、铁氟龙和铝等单个或者多个组合；内部密封层主要起到紧密封装隔绝内部与外部物质交流的作用，可以是聚烯烃、树脂和硅粘胶等单个或者多个组合。铝塑膜具有良好的弹性，可以充分释放充电和放电过程的膨胀力，确保中心区域膨胀力的均匀，降低极化差异，避免极化引发的局部析锂或者极片断裂。优选的，在本申请实施例中，采用铝塑膜作为制作缓冲件的材料。需要指出的是，还可以采用其他材料代替铝塑膜制作所述缓冲件，只要能够满足弹性以及密封的要求，本申请在这里不做限定。
本申请的一些实施例中，图15所示出了缓冲件300的成型过程以及 所述缓冲件300的剖视图。所述缓冲件采用铝塑膜301压制而成，所述铝塑膜301经过磨具冲坑工艺，在中心位置形成具有一定深度和面积的凹坑，将冲孔后的铝塑膜通过热封工艺，将其热封在一起，在热封时，所述内部密封层被融化后，黏合在一起，形成封装区域3010，所述封装区域3010将所述凹坑密封形成容纳腔305。所述内部密封层起到对所述容纳腔内的物质的密封的作用，所述外部保护层形成对密封层的保护。在成型时，可以将压制成型的两片铝塑膜上下相对密封，形成缓冲件；也可以直接将一片冲坑后的铝塑膜进行对折以后，直接对其密封形成缓冲件。对所述铝塑膜进行冲坑密封后，在所述缓冲件的外周形成至少一个封装结构和容纳腔。当然，需要指出的是，上述实施例中以热封工艺为例进行说明形成封装区域，可选的，还可以采用其他工艺形成封装区域，比如采用胶粘等等，在这里不做限定。通过采用上述工艺结构，制作工艺简单，密封效果好，容易制成适应于电芯结构的各种缓冲件。
根据本申请提出的一些实施例，所述缓冲件的容纳腔内填充有惰性流体。在本申请的实施例中，为了增强所述缓冲件的使用效果，本申请实施例中在所述缓冲件的容纳腔内，在封装时，可以填充可变形的惰性流体物质，比如：氩气、氮气、石蜡或硅油等，在非纯液体填充的情况下，所述容纳腔的压强不低于所述电芯内部残余空间的压强(通常情况下，所述电芯内部的压强为0.1～0.2MPa)；在采用纯液体进行填充的情况下，所述容纳腔完全填满。本申请实施例通过在所述容纳腔内填充惰性物质，避免了所述缓冲件的容纳腔在电芯温度升高时，由于自身包含的物质或材料带来的膨胀，从而避免了缓冲件自身的膨胀挤压电芯的膨胀空间。
根据本申请提出的一些实施例，还提出了一种电池2100，如图16所示，所述电池可以包括上述实施例中所述的一个或多个电池单体1000，以及汇流部件2101。
所述汇流部件2101将所述一个或多个电池单体1000实现串联或者并联的电连接。
所述一个或多个电池单体1000包括至少电芯200和缓冲件300，所述缓冲件300采用上述实施例中提到的封装结构，与所述电芯200的侧壁对应设置，用于在所述电芯200发生膨胀时，打开所述封装结构，为电芯的 的膨胀提供缓冲空间。
根据本申请提出的一些实施例，还提供一种用电装置，所述用电装置包括上述实施例中提出的电池2100，所述电池用于为所述用电装置提供电能。所述用电装置可以为但不限于手机、平板、笔记本电脑、电动玩具、电动工具、电瓶车、电动汽车、轮船、航天器等等。其中，电动玩具可以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，航天器可以包括飞机、火箭、航天飞机和宇宙飞船等等。
为了更好的体现本申请实施例提出的技术方案的技术效果，本申请人对图17至图19提供的电池单体的电芯膨胀力进行测试。图17为常用的电池单体结构，在该电池单体结构中，并没有采用缓冲件进行膨胀力的处理，图18所示的电池单体，缓冲件设置在电芯的侧壁与壳体之间，所述缓冲件采用间隔的封装结构进行封装，图19的电池单体，缓冲件设置在电芯的侧壁与壳体之间，所述缓冲件采用连续封装的梯形封装结构进行封装。
本申请人对采用上述三种结构的电池单体进行了如下测试：
测试一：
电池单体结构如图17所示，包括电芯200和壳体100，不含缓冲件。通过卷绕将LFP正极/负极/隔离膜卷绕成卷芯，对卷芯进行冷压，随后进行极耳焊接、入壳、顶盖焊接、Baking、注液直至成品电芯下仓，成品电池单体尺寸40*200*100mm，卷芯满充群裕度(卷芯满充群裕度＝100％SOC状态卷芯厚度/壳体内部厚度)98％，电芯满充群裕度(电芯满充群裕度＝(100％SOC状态卷芯厚度+初始缓冲腔厚度)/壳体内部厚度)98％，额定容量100Ah。对电池单体进行带三片铝板夹具与传感器的测试，初始夹具力1000N；使用恒温箱，在25℃温度，进行1C/1C循环保持率测试，实时记录膨胀力数据，直至容量衰减至90％SOH；
测试二：
图18中的电池单体，包括电芯200、壳体100和缓冲件300，采用铝塑膜厚度为150um，其中保护层70um，密封层80um；缓冲件300是二级密封层设计，第一封装区域采用180℃，100kgf，1s热压，宽度1mm，强度3N/mm；第二封装区域采用190℃，150kgf，2s热压，宽度1mm，强度 8N/mm；通过卷绕将LFP正极/负极/隔离膜卷绕成卷芯，对卷芯进行冷压，随后进行极耳焊接、入壳、顶盖焊接、Baking、注液、化成直至成品电池单体下仓，成品电池单体尺寸40*200*100mm，卷芯满充群裕度93％，电芯满充群裕度98％，额定容量95Ah。电池单体带三片铝板夹具与传感器进行测试，初始夹具力1000N；使用恒温箱，在25℃温度，进行1C/1C循环保持率测试，实时记录膨胀力数据，直至容量衰减至90％SOH。
测试三：
图19中的电池单体，包括电芯200、壳体100和缓冲件300，采用铝塑膜厚度为150um，其中保护层70um，密封层80um；缓冲件采用梯形封装结构设计，采用180℃，200kgf，3s热压斜边封印条件，长边强度3N/mm，短边强度10N/mm；电池单体结构剖面图如图19所示，包括电芯、缓冲件和壳体；通过卷绕将LFP正极/负极/隔离膜卷绕成卷芯，对卷芯进行冷压，随后进行极耳焊接、入壳、顶盖焊接、Baking、注液直至成品电池单体下仓，成品电池单体尺寸40*200*100mm，卷芯满充群裕度93％，电芯满充群裕度98％，额定容量95Ah。电池单体进行带三片铝板夹具与传感器的测试，初始夹具力1000N；使用恒温箱，在25℃温度，进行1C/1C循环保持率测试，实时记录膨胀力数据，直至容量衰减至90％SOH。
测试结果如表1所示：
表1
No. 缓冲件设置 缓冲件结构 膨胀力
测试一 无 无 8000N
测试二 2个 二级封装缓冲件 5000N
测试三 2个 梯形封装缓冲件 5000N
通过上述测试，将测试二和测试三的结果与测试一进行对比，可以看出在所述电池单体中增加本申请实施例提出的缓冲件以后，整个电池单体的膨胀力显著下降，由原来的8000N，下降到5000N，下降幅度达到37.5％。因此，通过本申请实施例提出的方案，通过在电池单体中增加缓冲件，大大降低了电池单体的膨胀力，很好的解决了现有技术中存在的问题。
因此，综上所述，本申请实施例通过将所述缓冲件与所述电芯对应设置，一方面在能够在电芯未发生膨胀时，能够有效填满电芯与壳体之间的初始空隙，避免了电芯卷绕结构出现松散现象，避免了电极片析锂现象的 出现；另一方面，当电芯在使用过程中发生膨胀时，所述缓冲件受到电芯膨胀的挤压时可发生形变，当所述电芯的膨胀压力较小时，所述缓冲件的形变较小，而随着所述电芯膨胀压力的逐步增大到一定程度时，所述缓冲件的封装区域逐步打开，所述容纳腔空间逐渐变大，则所述缓冲件发生的形变也逐渐变大，从而缓解了电芯膨胀带来的压力，实现了在电芯的全生命周期内，电芯和壳体之间的空隙能够被缓冲件所填满，减小了电芯膨胀对极片的影响和避免了析锂现象的出现。
最后应说明的是：以上各实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述各实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的范围，其均应涵盖在本申请的权利要求和说明书的范围当中。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 (17)

  1. 一种电池单体，其特征在于，包括：
    壳体；
    至少一个电芯，容纳于所述壳体内；以及
    缓冲件，容纳于所述壳体内，并与所述电芯的侧壁对应设置，所述缓冲件具有容纳腔，所述容纳腔的外周包括至少一个封装结构，所述封装结构包括至少一级具有预定长度的封装区域，当所述容纳腔内的压力超过所述封装结构的封装强度时，所述封装区域打开并形成与所述容纳腔连通的缓冲空间。
  2. 如权利要求1所述的电池单体，其特征在于，所述侧壁包括位于所述电芯高度方向的两个端部中间区域的中间侧壁部分，所述缓冲件与所述中间侧壁部分对应设置。
  3. 如权利要求1至2中任一项所述的电池单体，其特征在于，所述缓冲件设置在所述电芯与所述壳体的侧壁之间，和/或，所述缓冲件设置在相邻的所述电芯之间。
  4. 如权利要求1至3中任一项所述的电池单体，其特征在于，所述封装结构位于所述缓冲件沿所述电芯高度方向上的一端或两端。
  5. 如权利要求4所述的电池单体，其特征在于，在所述电芯的高度方向上，所述容纳腔的高度为所述电芯高度的10～90％。
  6. 如权利要求1至5中任一项所述的电池单体，其特征在于，所述封装结构包括至少两级具有不同封装强度的封装区域，使得随着所述容纳腔内的压力增加，所述封装区域逐级打开，并逐级形成与所述容纳腔连通的缓冲空间。
  7. 如权利要求6中任一项所述的电池单体，其特征在于，
    至少两级所述封装区域连续布置；和/或
    至少两级所述封装区域间隔布置，在相邻的两级所述封装区域之间设有预定长度的缓冲区。
  8. 如权利要求6至7中任一项所述的电池单体，其特征在于，至少两级所述封装区域沿所述电芯的高度方向布置，并且距离所述容纳腔较远的所述封装区域具有较大的封装强度。
  9. 如权利要求1至8中任一项所述的电池单体，其特征在于，所述容纳腔内的压力大于等于所述电池单体内部的气压。
  10. 如权利要求1至9中任一项所述的电池单体，其特征在于，所述封装结构的封装强度为0.1～50MPa。
  11. 如权利要求1至10中任一项所述的电池单体，其特征在于，所述电芯为方形电芯，并且
    所述缓冲件设置于所述电芯在厚度方向上的一端或者两端；和/或
    所述缓冲件设置于所述电芯在宽度方向上的一端或者两端。
  12. 如权利要求11所述的电池单体，其特征在于，当所述缓冲件设置于所述电芯在厚度方向上的一端或两端时，在所述电芯的宽度方向上，所述容纳腔的宽度为所述电芯宽度的50～100％。
  13. 如权利要求1至10中任一项所述的电池单体，其特征在于，所述容纳腔在所述电芯的高度方向上的截面呈环形，连续地包围所述电芯。
  14. 如权利要求1至13中任一项所述的电池单体，其特征在于，所述缓冲件的材料具有外部保护层和内部密封层，所述封装区域通过对所述内部密封层进行热封形成。
  15. 如权利要求1至14中任一项所述的电池单体，其特征在于，所述容纳腔内填充有惰性流体。
  16. 一种电池，其特征在于，包括：如权利要求1至15中任一项所述的电池单体。
  17. 一种用电装置，其特征在于，所述用电装置包括如权利要求16所述的电池，所述电池用于提供电能。
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CN209087934U (zh) * 2018-11-06 2019-07-09 北京长城华冠汽车科技股份有限公司 一种端板及电池模组

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WO2023197858A1 (zh) * 2022-04-12 2023-10-19 宁德时代新能源科技股份有限公司 电池单体、电池以及用电装置
CN116151051A (zh) * 2023-04-24 2023-05-23 四川新能源汽车创新中心有限公司 一种锂离子电池注液量确定方法
CN116151051B (zh) * 2023-04-24 2023-08-15 四川新能源汽车创新中心有限公司 一种锂离子电池注液量确定方法

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