WO2024031501A1 - 电池单体、电池以及用电装置 - Google Patents

电池单体、电池以及用电装置 Download PDF

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Publication number
WO2024031501A1
WO2024031501A1 PCT/CN2022/111636 CN2022111636W WO2024031501A1 WO 2024031501 A1 WO2024031501 A1 WO 2024031501A1 CN 2022111636 W CN2022111636 W CN 2022111636W WO 2024031501 A1 WO2024031501 A1 WO 2024031501A1
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WIPO (PCT)
Prior art keywords
battery cell
wall
tab
weak
welding
Prior art date
Application number
PCT/CN2022/111636
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English (en)
French (fr)
Inventor
李萌
Original Assignee
宁德时代新能源科技股份有限公司
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Priority to PCT/CN2022/111636 priority Critical patent/WO2024031501A1/zh
Publication of WO2024031501A1 publication Critical patent/WO2024031501A1/zh

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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
    • H01M50/10—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
    • H01M50/147—Lids or covers
    • H01M50/148—Lids or covers characterised by their shape
    • H01M50/15—Lids or covers characterised by their shape 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
    • H01M50/209—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
    • H01M50/50—Current conducting connections for cells or batteries

Definitions

  • the present application relates to the field of battery technology, and more specifically, to a battery cell, a battery and an electrical device.
  • Battery cells are widely used in electronic devices, such as mobile phones, laptops, battery cars, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, electric tools, etc.
  • the present application provides a battery cell, a battery and an electrical device, which can improve the energy density of the battery cell.
  • a battery cell including a casing and an electrode assembly.
  • the housing includes a first wall.
  • a first tab is provided at one end of the electrode assembly facing the first wall, and the first tab is welded to the first wall to form a welding portion.
  • the first tab of the electrode assembly is directly welded to the first wall of the casing, thereby eliminating the need for conventional adapter components, improving the energy density of the battery cell, and shortening the distance between the electrode assembly and the casing. Conductive paths, reduce heat generation, and improve the charge and discharge performance of battery cells.
  • the first wall and the first tab can be welded from the outside of the casing, which can reduce the risk of metal particles generated by welding entering the inside of the casing and improve safety.
  • the first tab is wound and includes N turns of tab layers, and the number of tab layers connected to the welding part is n, n/N ⁇ 0.2.
  • the current on the tab layer directly connected to the welding part can be directly conducted to the first wall through the welding part; the current on the tab layer not connected to the welding part needs to be conducted to the tab directly connected to the welding part first. layer before it can be conducted through the weld to the first wall.
  • the above technical solution makes n/N greater than or equal to 0.2, so that the welding part connects more tab layers, reduces the distance between the tab layer that is not directly connected to the welding part and the welding part, and shortens multiple tab layers.
  • the conductive path between the first wall and the first wall reduces the internal resistance and improves the overcurrent capability.
  • n/N 0.5.
  • the above technical solution can further increase the number of tab layers connected to the welding part, thereby shortening the conductive paths between the multiple tab layers and the first wall, reducing internal resistance, and improving overcurrent capability.
  • the welding portion is linear, V-shaped or arc-shaped.
  • the first wall is circular. There are multiple welding parts, and the multiple welding parts are arranged at intervals along the circumferential direction of the first wall.
  • multiple welding parts can improve the overcurrent capability.
  • the total welding area is constant, by increasing the number of welding parts, the heat generated in a single welding can be reduced and the risk of burning the electrode assembly can be reduced.
  • the first wall is provided with a pressure relief structure, and the pressure relief structure is spaced apart from the welding portion.
  • the pressure relief structure can release the internal materials of the battery cell when the battery cell is thermally out of control, thereby reducing the risk of battery cell fire and explosion and improving safety. Setting the pressure relief structure and the welding part at intervals can reduce the risk of the pressure relief structure being damaged by high temperatures during the welding process and improve the reliability of the pressure relief structure.
  • the first wall is circular; the pressure relief structure includes a plurality of first weak portions, and the plurality of first weak portions are arranged circumferentially along the first wall.
  • the first wall when the battery cell is thermally out of control, the first wall can be broken at a plurality of first weak parts to form a discharge channel, thereby reducing the risk of battery cell explosion.
  • the efficiency of pressure relief can be improved.
  • a plurality of welding portions are provided, and the plurality of welding portions and the plurality of first weak portions are arranged circumferentially.
  • multiple welding parts and multiple first weak parts are arranged in the circumferential direction, which can not only increase the flow area between the first wall and the first tab, but also make use of the space between the welding parts.
  • the first weak point is to improve the safety of battery cells.
  • the plurality of welding portions and the plurality of first weak portions are alternately arranged in the circumferential direction.
  • the above technical solution evenly distributes multiple welding parts and multiple first weak parts, thereby reducing the difference in force of multiple welding parts when the battery cell vibrates, and reducing the number of battery cells when the battery cell is thermally out of control. Differences in positional relief efficiency.
  • the first weak section includes a first weak section and a second weak section, there are two first weak sections, the first weak section extends along the radial direction of the first wall, and the two first weak sections extend along the radial direction of the first wall. Circumferential spacing setting.
  • the second weak section connects the ends of the two first weak sections close to the center of the first wall.
  • the first weak section and the second weak section rupture under the internal pressure of the battery cell, and the area surrounded by the two first weak sections and one second weak section moves towards Fold outward to form a pressure relief channel.
  • the pressure relief channel can quickly release the internal contents of the battery cell to reduce the risk of battery cell explosion.
  • the first weakened portion extends radially along the first wall.
  • the pressure relief structure also includes an annular second weak portion, and a plurality of first weak portions surround the outside of the second weak portion and are connected to the second weak portion.
  • the second weak part ruptures first, and the area surrounded by the second weak part breaks away from the battery cell under the impact of high-temperature and high-pressure substances; then, the first weak part gradually ruptures, and the adjacent first weak part
  • the fan-shaped area between the two parts can be folded outward to form a pressure relief channel.
  • a surface of the first wall facing away from the first tab is provided with reinforcing ribs.
  • the reinforcing ribs can increase the strength of the first wall, reduce the deformation of the first wall during the process of assembling the battery cells, and reduce the risk of damage and aging of the first weak part due to the deformation of the first wall. , improve the accuracy of actuation of the pressure relief structure.
  • the first wall is provided with a plurality of reinforcing ribs, and the plurality of reinforcing ribs and the plurality of first weak portions are alternately arranged along the circumferential direction.
  • each first weak part is provided with reinforcing ribs on both sides in the circumferential direction.
  • the two adjacent reinforcing ribs can effectively reduce the deformation of the areas on both sides of the first weak part and reduce the deformation of the first weak part. Reduce the risk of breakage and aging, and improve the accuracy of actuation of the pressure relief structure.
  • the first wall includes a body part and a protruding part, the protruding part protrudes from a surface of the body part facing the first pole and offsets the first pole, and the protruding part is welded to the first pole and formed Welding Department.
  • the pressure relief structure is located on the main body.
  • the convex part offsets the first pole to separate the body part and the first pole at a certain distance.
  • the first tab is not easy to squeeze the body part, which can reduce the risk of deformation of the body part, thereby reducing the risk of damage and aging of the pressure relief structure due to the deformation of the body part, and improving the pressure relief structure Actuation accuracy.
  • the first wall forms a recess at a position corresponding to the protrusion, the recess being recessed relative to a surface of the body portion facing away from the first tab.
  • the portion of the convex portion corresponding to the bottom surface of the concave portion is welded to the first tab and forms a welding portion.
  • the thickness of the convex portion can be reduced, the difficulty of welding the convex portion and the first tab is reduced, the heat generated during the welding process is reduced, the risk of the electrode assembly being burned is reduced, and the safety is improved.
  • the plurality of protrusions can stably press and support the first tab, reduce the pressure between the first wall and the first tab, and reduce the deformation of the first tab and the first wall.
  • the weld is configured to break when the pressure relief structure releases internal contents of the battery cell to disconnect the first wall from the first tab.
  • the housing includes a housing having an opening and an end cap for covering the opening.
  • the end cap is the first wall.
  • the housing is electrically connected to the first tab through the end cap.
  • the battery cell also includes an electrode terminal installed on the casing, and the electrode terminal is located on a side of the electrode assembly away from the end cap.
  • the electrode assembly is provided with a second tab on one end facing the electrode terminal. The polarity of the second tab is opposite to the polarity of the first tab.
  • the second tab is electrically connected to the electrode terminal.
  • the casing and the electrode terminal can be used as the two output poles of the battery cell, thus eliminating a traditional electrode terminal and simplifying the structure of the battery cell.
  • the housing can be electrically connected to the bus component, which can not only increase the flow area, but also make the structural design of the bus component more flexible. .
  • embodiments of the present application provide a battery, including a plurality of battery cells provided in any embodiment of the first aspect.
  • embodiments of the present application provide an electrical device, including the battery of the second aspect, and the battery is used to provide electrical energy.
  • Figure 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application.
  • FIG. 2 is an exploded schematic diagram of a battery provided by some embodiments of the present application.
  • FIG 3 is an exploded schematic diagram of the battery module shown in Figure 2;
  • Figure 4 is a schematic structural diagram of a battery cell provided by some embodiments of the present application.
  • FIG. 5 is an exploded schematic diagram of the battery cell shown in Figure 4.
  • Figure 6 is a schematic cross-sectional view of the battery cell shown in Figure 4.
  • Figure 7 is an enlarged schematic diagram of Figure 6 at box A;
  • Figure 8 is a schematic structural diagram of an electrode assembly of a battery cell provided by some embodiments of the present application.
  • Figure 9 is a schematic bottom view of a battery cell provided by some embodiments of the present application.
  • Figure 10 is a schematic structural diagram of the end cap described in Figure 9;
  • Figure 11 is a schematic top view of the end cap shown in Figure 10;
  • Figure 12 is a schematic cross-sectional view taken along line B-B in Figure 11;
  • Figure 13 is a schematic structural diagram of an end cover of a battery cell provided by other embodiments of the present application.
  • Figure 14 is another structural schematic diagram of the end cap shown in Figure 13, in which the area surrounded by the first weak portion of the end cap is folded;
  • Figure 15 is a schematic structural diagram of an end cover of a battery cell provided by other embodiments of the present application.
  • Figure 16 is a schematic cross-sectional view of the end cap shown in Figure 15;
  • Figure 17 is a partial cross-sectional schematic view of a battery cell provided by other embodiments of the present application.
  • FIG. 18 is a schematic structural diagram of the end cap shown in FIG. 17 .
  • an embodiment means that a particular feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the application.
  • the appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.
  • connection should be understood in a broad sense.
  • connection can be a fixed connection, It can also be detachably connected or integrally connected; it can be directly connected or indirectly connected through an intermediate medium; it can be internal communication between two components.
  • connection can be a fixed connection
  • connection can also be detachably connected or integrally connected; it can be directly connected or indirectly connected through an intermediate medium; it can be internal communication between two components.
  • connection can also be detachably connected or integrally connected; it can be directly connected or indirectly connected through an intermediate medium; it can be internal communication between two components.
  • “Plural” appearing in this application means two or more (including two).
  • battery cells may include lithium ion secondary battery cells, lithium ion primary battery cells, lithium sulfur battery cells, sodium lithium ion battery cells, sodium ion battery cells or magnesium ion battery cells, etc.
  • the embodiments of the present application are not limited to this.
  • the battery cell may be in the shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes, and the embodiments of the present application are not limited to this.
  • the battery mentioned in the embodiments of this application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.
  • the battery mentioned in this application may include a battery module or a battery pack.
  • Batteries generally include a box for packaging one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.
  • the battery cell includes an electrode assembly and an electrolyte.
  • the electrode assembly includes a positive electrode piece, a negative electrode piece and a separator. Battery cells mainly rely on the movement of metal ions between the positive and negative electrodes to work.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer.
  • the positive electrode active material layer is coated on the surface of the positive electrode current collector; the positive electrode current collector includes a positive electrode current collecting area and a positive electrode tab protruding from the positive electrode current collecting area.
  • the positive electrode current collecting area The positive electrode active material layer is coated on the positive electrode tab, and at least part of the positive electrode tab is not coated with the positive electrode active material layer.
  • the material of the cathode current collector can be aluminum, and the cathode active material layer includes cathode active materials.
  • the cathode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganate, etc.
  • the negative electrode piece includes a negative electrode current collector and a negative electrode active material layer.
  • the negative electrode active material layer is coated on the surface of the negative electrode current collector; the negative electrode current collector includes a negative electrode current collecting area and a negative electrode tab protruding from the negative electrode current collecting area.
  • the negative electrode current collecting area The negative electrode active material layer is coated on the negative electrode tab, and at least part of the negative electrode tab is not coated with the negative electrode active material layer.
  • the negative electrode current collector may be made of copper, and the negative electrode active material layer may include a negative electrode active material.
  • the negative electrode active material may be carbon or silicon.
  • the material of the isolator can be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene), etc.
  • the battery cell also includes a casing, the casing has a receiving cavity, and the electrode assembly and the electrolyte are received in the receiving cavity.
  • the housing protects the electrode assembly and reduces the risk of other foreign matter affecting the electrode assembly.
  • two electrode terminals are usually provided on the casing; the two electrode terminals are electrically connected to the positive electrode piece and the negative electrode piece respectively to facilitate the extraction of electric energy from the electrode assembly.
  • the inventor tried to use the outer casing as an electrode of the battery cell.
  • the casing can be electrically connected to the positive electrode piece or the negative electrode piece, so that the casing serves as an electrode of the battery cell, thus saving one electrode terminal and simplifying the structure of the battery cell.
  • the housing is usually electrically connected to the pole piece through an adapter component.
  • the adapter component will occupy the internal space of the battery cell, reduce the energy density of the battery cell, increase the assembly process related to the adapter component, and affect the molding efficiency of the battery cell.
  • embodiments of the present application provide a technical solution, which directly welds the tabs of the electrode assembly to the wall of the casing, thereby eliminating the need for adapter components in conventional technology, improving the energy density of the battery cells, and also Shorten the conductive path between the electrode assembly and the casing, reduce heat generation, and improve the charge and discharge performance of the battery cell.
  • Electrical devices can be vehicles, cell phones, portable devices, laptops, ships, spacecraft, electric toys and power tools, etc.
  • Vehicles can be fuel vehicles, gas vehicles or new energy vehicles, and new energy vehicles can be pure electric vehicles, hybrid vehicles or extended-range vehicles, etc.
  • spacecraft include aircraft, rockets, space shuttles, spaceships, etc.
  • electric toys include fixed Type or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc.
  • electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, for example, Electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, planers and more.
  • Electric drills Electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, planers and more.
  • the following embodiments take the electrical device as a vehicle as an example.
  • Figure 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application.
  • a battery 2 is provided inside the vehicle 1 , and the battery 2 can be provided at the bottom, head, or tail of the vehicle 1 .
  • the battery 2 may be used to power the vehicle 1 , for example, the battery 2 may be used as an operating power source for the vehicle 1 .
  • the vehicle 1 may also include a controller 3 and a motor 4.
  • the controller 3 is used to control the battery 2 to provide power to the motor 4, for example, to meet the power requirements for starting, navigation and driving of the vehicle 1.
  • the battery 2 can not only be used as the operating power source of the vehicle 1, but also can be used as the driving power source of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.
  • Figure 2 is an exploded schematic diagram of a battery provided by some embodiments of the present application.
  • the battery 2 includes a case 5 and a battery cell (not shown in FIG. 2 ), and the battery cell is accommodated in the case 5 .
  • the box 5 is used to accommodate battery cells, and the box 5 can be of various structures.
  • the box body 5 may include a first box body part 5a and a second box body part 5b.
  • the first box body part 5a and the second box body part 5b cover each other.
  • the first box body part 5a and the second box body part 5b cover each other.
  • the two box portions 5b jointly define an accommodating space 5c for accommodating battery cells.
  • the second box part 5b can be a hollow structure with one end open, and the first box part 5a is a plate-like structure.
  • the first box part 5a is covered with the opening side of the second box part 5b to form a receiving space 5c.
  • the box body 5; the first box body part 5a and the second box body part 5b can also be a hollow structure with one side open, and the opening side of the first box body part 5a is covered with the opening side of the second box body part 5b , to form a box 5 having an accommodation space 5c.
  • the first box part 5a and the second box part 5b can be in various shapes, such as cylinder, rectangular parallelepiped, etc.
  • a sealing member may also be provided between the first box part 5a and the second box part 5b, such as sealant, sealing ring, etc. .
  • the first box part 5a can also be called an upper box cover, and the second box part 5b can also be called a lower box.
  • the battery 2 there may be one battery cell or a plurality of battery cells. If there are multiple battery cells, the multiple battery cells can be connected in series, in parallel, or in mixed connection. Mixed connection means that multiple battery cells are connected in series and in parallel. Multiple battery cells can be directly connected in series or parallel or mixed together, and then the whole composed of multiple battery cells can be accommodated in the box 5; of course, multiple battery cells can also be connected in series or parallel first or A battery module 6 is formed by a mixed connection, and multiple battery modules 6 are connected in series, parallel, or mixed to form a whole, and are accommodated in the box 5 .
  • FIG. 3 is an exploded schematic diagram of the battery module shown in FIG. 2 .
  • FIG. 3 there are multiple battery cells 7 , and the plurality of battery cells 7 are first connected in series, parallel, or mixed to form the battery module 6 .
  • a plurality of battery modules 6 are connected in series, parallel, or mixed to form a whole, and are accommodated in the box.
  • the plurality of battery cells 7 in the battery module 6 can be electrically connected through bus components to achieve parallel, series or mixed connection of the plurality of battery cells 7 in the battery module 6 .
  • Figure 4 is a schematic structural view of a battery cell provided by some embodiments of the present application
  • Figure 5 is an exploded schematic view of the battery cell shown in Figure 4
  • Figure 6 is a schematic cross-sectional view of the battery cell shown in Figure 4
  • Figure 7 This is an enlarged schematic diagram of Figure 6 at box A.
  • the battery cell 7 in the embodiment of the present application includes a casing 20 and an electrode assembly 10.
  • the casing 20 includes a first wall 20a.
  • the electrode assembly 10 is provided with a first tab at one end facing the first wall 20a. 11.
  • the first tab 11 is welded to the first wall 20a to form a welding portion 30.
  • the casing 20 has a hollow structure, and an accommodation cavity for accommodating the electrode assembly 10 and the electrolyte is formed inside.
  • the shape of the housing 20 can be determined according to the specific shape of the electrode assembly 10 . For example, if the electrode assembly 10 has a rectangular parallelepiped structure, a rectangular parallelepiped housing can be used; if the electrode assembly 10 has a cylindrical structure, a cylindrical housing can be used.
  • the housing 20 can be made of various materials.
  • the housing 20 can be made of metal.
  • the material of the housing 20 may be copper, iron, aluminum, steel, aluminum alloy, etc.
  • the first wall 20a is a wall of the housing 20 with a certain thickness. It can be the top wall of the housing 20, the bottom wall of the housing 20, or the side wall of the housing 20. This is not limited in the embodiment of the present application.
  • the electrode assembly 10 includes a first pole piece and a second pole piece with opposite polarities.
  • One of the first pole piece and the second pole piece is a positive pole piece, and the other is a negative pole piece.
  • the electrode assembly 10 generates electrical energy through oxidation and reduction reactions during the insertion/extraction of ions in the positive electrode piece and the negative electrode piece.
  • the electrode assembly 10 further includes a separator, which is used to insulate the first pole piece and the second pole piece.
  • the electrode assembly 10 may be a rolled structure formed by rolling a first pole piece, a separator, and a second pole piece.
  • the electrode assembly 10 may also be a laminated structure formed by a stacked arrangement of a first pole piece, a separator, and a second pole piece.
  • the first tab 11 may be a portion of the first pole piece that is not coated with the active material layer.
  • the welding portion 30 may be linear, arcuate, V-shaped, circular, oval, rectangular or other shapes.
  • the first tab 11 of the electrode assembly 10 is directly welded to the first wall 20a of the casing 20, thereby eliminating the need for conventional adapter components, improving the energy density of the battery cell 7, and shortening the battery life.
  • the conductive path between the electrode assembly 10 and the casing 20 reduces heat generation and improves the charging and discharging performance of the battery cell 7 .
  • the first wall 20a and the first tab 11 can be welded from the outside of the housing 20, which can reduce the risk of metal particles generated by welding entering the inside of the housing 20 and improve safety.
  • the first wall 20a is welded to the first tab 11 by laser welding.
  • a laser can be irradiated on the surface of the first wall 20a facing away from the first tab 11. The laser melts a part of the first wall 20a and a part of the first tab 11 and forms a molten pool. After the molten pool solidifies, a welding part is formed. 30.
  • the housing 20 includes a housing 21 having an opening and an end cap 22 for covering the opening.
  • the casing 21 is a component used to cooperate with the end cap 22 to form an internal cavity of the battery cell 7 .
  • the formed internal cavity can be used to accommodate the electrode assembly 10 , electrolyte and other components.
  • Housing 21 and end cap 22 may be separate components.
  • an opening can be provided on the casing 21 , and the end cover 22 covers the opening at the opening to form an internal cavity of the battery cell 7 .
  • the housing 21 can be of various shapes and sizes, such as rectangular parallelepiped, cylinder, hexagonal prism, etc. Specifically, the shape of the housing 21 can be determined according to the specific shape and size of the electrode assembly 10 .
  • the housing 21 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., which are not particularly limited in the embodiment of the present application.
  • the shape of the end cap 22 can be adapted to the shape of the housing 21 to fit the housing 21 .
  • the end cap 22 can be made of a material with a certain hardness and strength (such as aluminum alloy). In this way, the end cap 22 is less likely to deform when subjected to extrusion and collision, so that the battery cell 7 can have higher durability. Structural strength and safety performance can also be improved.
  • the housing 21 may have a structure with an opening on one side, and the end cover 22 is provided as one and covers the opening of the housing 21 .
  • the housing 21 may also have a structure with openings on both sides, and two end caps 22 are provided, and the two end caps 22 cover the two openings of the housing 21 respectively.
  • the end cap 22 is connected to the housing 21 by welding, bonding, snapping or other means.
  • the first wall 20a may be the end cover 22 or the wall of the housing 21.
  • end cap 22 is first wall 20a.
  • the end cap 22 is directly welded to the first tab 11 and forms a welding portion 30 .
  • the housing 21 is electrically connected to the first tab 11 through the end cap 22 .
  • the housing 21 is welded to the end cover 22 so that the housing 21 and the end cover 22 are electrically connected.
  • the casing 21 itself can serve as the output pole of the battery cell 7, thus eliminating a traditional electrode terminal and simplifying the structure of the battery cell 7.
  • the housing 21 can be electrically connected to the bus component, which can not only increase the flow area, but also make the structural design of the bus component more flexible.
  • the battery cell 7 further includes an electrode terminal 40 installed on the housing 21 , and the electrode terminal 40 is located on a side of the electrode assembly 10 away from the end cap 22 .
  • the electrode assembly 10 is provided with a second tab 12 at one end facing the electrode terminal 40 .
  • the polarity of the second tab 12 is opposite to that of the first tab 11 .
  • the second tab 12 is electrically connected to the electrode terminal 40 .
  • the second tab 12 may be a portion of the second pole piece that is not coated with the active material layer.
  • the first tab 11 and the second tab 12 are respectively provided at both ends of the electrode assembly 10 .
  • the case 21 and the electrode terminal 40 can serve as the two output poles of the battery cell 7 .
  • the housing 21 includes a second wall 211 opposite the end cap 22 and the electrode terminal 40 is mounted on the second wall 211 .
  • the second wall 211 and the electrode terminal 40 can serve as the two output poles of the battery cell 7 , which can simplify the structure of the battery cell 7 and ensure the overcurrent capability of the battery cell 7 .
  • the second wall 211 and the electrode terminal 40 are located at the same end of the battery cell 7. In this way, when multiple battery cells 7 are assembled into a group, the bus parts can be assembled to the same side of the battery cell 7, which can simplify the assembly process. , improve assembly efficiency.
  • the battery cells 7 are cylindrical battery cells.
  • the housing 21 is cylindrical.
  • the base material of the case 21 and the end cover 22 are the same, which can ensure the welding strength of the case 21 and the end cover 22 and ensure the sealing of the battery cell 7 .
  • FIG. 8 is a schematic structural diagram of an electrode assembly of a battery cell provided by some embodiments of the present application
  • FIG. 9 is a schematic bottom view of a battery cell provided by some embodiments of the present application.
  • the electrode assembly 10 is a rolled structure.
  • the first tab 11 is wound and includes N turns of tab layers 111.
  • the number of tab layers 111 connected to the welding portion 30 is n, and n/N ⁇ 0.2.
  • N and n are both positive integers greater than 1.
  • the two ends of the first tab 11 along the winding direction W are the inner end 11 a and the outer end 11 b respectively.
  • this embodiment divides the tab layer 111 based on the inner end 11 a of the first tab 11 .
  • the inner end 11a of the first tab 11 is the head end of the first tab layer 111
  • the tail end of the first tab layer 111 and the head end of the first tab layer 111 are in the first tab 11
  • the first tab layer 111 circles around the central axis of the electrode assembly 10
  • the tail end of the first tab layer 111 is the head end of the second tab layer 111
  • the N tab layers 111 are connected end to end along the winding direction W.
  • each tab layer 111 circles the central axis.
  • the inner end 11a and the outer end 11b of the first tab 11 may not be aligned in the radial direction of the first tab 11, so that the last tab layer 111 circles the central axis less than one circle, for example, The last tab layer 111 can surround the central axis by 1/4 turn, 1/3 turn, 1/2 turn, 2/3 turn or 3/4 turn.
  • the current between the first wall and the first tab 11 is mainly conducted through the welding portion 30 .
  • the welding part 30 can reduce the resistance between the first wall and the first tab 11 and improve the overcurrent capability.
  • this embodiment makes n/N greater than or equal to 0.2, so that the welding part 30 connects more tab layers 111 and reduces the gap between the tab layers 111 that are not directly connected to the welding part 30 and the welding part 30 distance, shortening the conductive path between the plurality of tab layers 111 and the first wall, reducing internal resistance, and improving overcurrent capability.
  • n/N 0.5.
  • n/N may be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9.
  • the first tab 11 is generally cylindrical, and there is a gap between two adjacent tab layers 111 .
  • the first tab 11 can be processed to reduce the gap between the tab layers 111 to facilitate the connection between the first tab 11 and the first wall.
  • some embodiments of the present application can perform a flattening process on the first tab 11 so that the end areas of the first tab 11 are gathered and brought together; the flattening process is performed on the first tab 11 facing the first wall.
  • One end forms a dense end surface to reduce the gap between the tab layers 111 and facilitate the welding of the first tab 11 and the first wall.
  • some embodiments of the present application may also fill conductive material between two adjacent circles of tab layers 111 to reduce the gap between the tab layers 111 .
  • the welding portion 30 is linear, V-shaped or arc-shaped.
  • the first wall is circular.
  • a plurality of welding parts 30 are provided, and the plurality of welding parts 30 are arranged at intervals along the circumferential direction Y of the first wall.
  • the number of welding parts 30 can be determined according to the overcurrent capability requirements of the battery cells 7 .
  • the number of welding parts 30 may be 2, 3, 4 or more.
  • Multiple welding parts 30 can improve the overcurrent capability.
  • the heat generated in a single welding can be reduced and the risk of burning the electrode assembly 10 can be reduced.
  • the first wall is circular, and the welding portion 30 extends along a radial direction of the first wall.
  • the radial direction of the first wall is parallel to the radial direction of the first tab 11 .
  • the welding portion 30 extending along the radial direction of the first wall can connect more tab layers 111, thereby shortening the conductive paths between the plurality of tab layers 111 and the first wall, reducing internal resistance, and improving overcurrent capability.
  • Figure 10 is a schematic structural view of the end cap shown in Figure 9;
  • Figure 11 is a schematic top view of the end cap shown in Figure 10;
  • Figure 12 is a schematic cross-sectional view taken along line B-B in Figure 11.
  • the first wall is provided with a pressure relief structure 221 , and the pressure relief structure 221 is spaced apart from the welding part 30 .
  • the pressure relief structure 221 has an important impact on the safety of the battery cell 7 . For example, when short circuit, overcharge, etc. occur, thermal runaway may occur inside the battery cell 7 and the pressure may rise suddenly. In this case, the internal pressure can be released outward by actuating the pressure relief structure 221 to prevent the battery cell 7 from exploding or catching fire.
  • the pressure relief structure 221 may be an element or component that is activated when the battery cell 7 reaches a certain condition.
  • the pressure relief structure 221 may be an element or component that is activated to relieve the internal pressure and/or internal substances when the internal pressure or internal temperature of the battery cell 7 reaches a predetermined threshold.
  • This threshold design varies based on design requirements. The threshold may depend on one or more materials of the positive electrode piece, the negative electrode piece, the electrolyte and the separator in the battery cell 7 .
  • the pressure relief structure 221 may take the form of an explosion-proof valve, an air valve, a pressure relief valve or a safety valve, etc., and may specifically adopt a pressure-sensitive element or structure, that is, when the internal pressure of the battery cell 7 reaches a predetermined threshold, the pressure relief The structure 221 performs an action or the weak area provided in the pressure relief structure 221 ruptures, thereby forming a pressure relief channel for internal pressure relief.
  • the pressure relief structure 221 may also adopt a temperature-sensitive element or structure. That is, when the internal temperature of the battery cell 7 reaches a predetermined threshold, the pressure relief structure 221 performs an action, thereby forming a pressure relief channel for the internal pressure to be released.
  • the pressure relief structure 221 may also be a component that can be actively actuated. For example, the pressure relief structure 221 may be actuated when receiving a control signal from the battery.
  • the “actuation” mentioned in this application means that the pressure relief structure 221 acts or is activated to a certain state, so that the internal pressure and/or internal materials of the battery cell 7 can be released.
  • the actions generated by the pressure relief structure 221 may include, but are not limited to: at least a portion of the pressure relief structure 221 is broken, broken, torn or opened, and the like.
  • the pressure relief structure 221 can be an independent component, which is fixed to the first wall by welding, bonding or other methods. Alternatively, the pressure relief structure 221 may also be integrally formed with the first wall.
  • the pressure relief structure 221 can release the internal contents of the battery cell 7 when the battery cell 7 is thermally out of control, thereby reducing the risk of fire or explosion of the battery cell 7 and improving safety.
  • the pressure relief structure 221 and the welding part 30 at intervals, the risk of the pressure relief structure 221 being damaged by high temperature during the welding process can be reduced, and the reliability of the pressure relief structure 221 can be improved.
  • the first wall is circular.
  • the pressure relief structure 221 includes a plurality of first weak portions 2211 arranged along the circumferential direction Y of the first wall.
  • the first weak portion 2211 is a relatively weak portion of the first wall, which is a portion of the first wall that is easily broken, broken, torn, or opened.
  • the strength of the first weak portion 2211 is less than the strength of the portion of the first wall close to the first weak portion 2211 .
  • grooves, notches, or other structures can be opened in a predetermined area of the first wall to reduce the local strength of the first wall, thereby forming a first weak portion 2211 on the first wall.
  • a thinning process is performed on a predetermined area of the first wall, and the thinned portion of the first wall forms the first weak portion 2211 .
  • material treatment can be performed on a predetermined area of the first wall so that the strength of this area is weaker than that of other areas. In other words, this area is the first weak portion 2211 .
  • the first wall may be broken at the plurality of first weak parts 2211 to form a discharge channel, thereby reducing the risk of the battery cell 7 exploding.
  • multiple welding portions 30 are provided, and the plurality of welding portions 30 and the plurality of first weak portions 2211 are arranged along the circumferential direction Y.
  • the plurality of welding portions 30 and the plurality of first weak portions 2211 surround the center of the first wall along the circumferential direction Y.
  • This embodiment does not limit the order in which the welding portion 30 and the first weak portion 2211 are arranged.
  • the plurality of welding portions 30 and the plurality of first weak portions 2211 may be alternately arranged along the circumferential direction Y, or may be irregularly arranged along the circumferential direction Y.
  • the number of welding portions 30 between two adjacent weak portions may be one or multiple.
  • multiple welding portions 30 and multiple first weak portions 2211 are arranged along the circumferential direction Y, which can not only increase the flow area between the first wall and the first tab 11 , but also utilize the welding portions 30 A first weak portion 2211 is provided in the space between them to improve the safety of the battery cell 7 .
  • the plurality of welding portions 30 and the plurality of first weak portions 2211 are alternately arranged along the circumferential direction Y.
  • the plurality of welding parts 30 and the plurality of first weak parts 2211 can be evenly distributed, thereby reducing the difference in force received by the plurality of welding parts 30 when the battery cell 7 vibrates, and reducing the thermal runaway of the battery cell 7 . Differences in discharge efficiency at multiple locations of a small battery cell.
  • the first weak portion 2211 extends radially along the first wall.
  • the pressure relief structure 221 also includes an annular second weak portion 2212. A plurality of first weak portions 2211 surround the outside of the second weak portion 2212 and are connected to the second weak portion 2212.
  • This embodiment of the present application does not limit the strength of the first weak portion 2211 and the strength of the second weak portion 2212.
  • the second weak part 2212 ruptures first, and the area surrounded by the second weak part 2212 separates from the battery cell 7 under the impact of high-temperature and high-pressure substances; then, the first weak part 2211 gradually ruptures.
  • the fan-shaped area between adjacent first weak portions 2211 can be folded outward to form a pressure relief channel.
  • the size of the pressure relief channel can be increased to improve the efficiency of material release inside the battery cell 7 .
  • the welding portion 30 is configured to break when the pressure relief structure 221 releases the internal content of the battery cell 7 to disconnect the first wall from the first tab 11 .
  • the first wall includes a flat body portion 222 , and the body portion 222 offsets the first tab 11 .
  • Grooves are formed on the surface of the body part 222 to form a first weak part 2211 and a second weak part 2212.
  • the body part 222 is welded to the first tab 11 to form the welding part 30 .
  • the welding portion 30 and the weak portion are both formed in the flat body portion 222 , which can save the height space occupied by the first wall and improve the energy density of the battery cell 7 .
  • the body part 222 is flat-shaped, and has sufficient area reserved for welding to meet over-current requirements, and can reduce positioning requirements during welding and improve welding efficiency.
  • the first wall further includes a limiting portion 223 surrounding the outside of the body portion 222 and protruding from the outer surface of the first wall.
  • the first wall is the end cap 22 , and the limiting portion 223 can be used to resist the housing 21 to prevent the end cap 22 from being excessively inserted into the housing 21 .
  • the limiting portion 223 is welded to the housing 21 .
  • Figure 13 is a schematic structural view of an end cover of a battery cell provided by other embodiments of the present application;
  • Figure 14 is another schematic structural view of the end cover shown in Figure 13, wherein the end cover is surrounded by the first weak portion Regional fold.
  • end cap 22 is the first wall.
  • the first weak section 2211 includes a first weak section 221a and a second weak section 221b.
  • the first weak section 221a is provided in two, and the first weak section 221a is along the first wall. Extending radially, the first weak sections 221a are spaced apart along the circumferential direction Y.
  • the second weak section 221b connects the ends of the two first weak portions 2211 close to the center of the first wall.
  • the area surrounded by the first weak portion 2211 is generally fan-shaped.
  • FIG. 15 is a schematic structural diagram of an end cover of a battery cell provided by other embodiments of the present application;
  • FIG. 16 is a schematic cross-sectional view of the end cover shown in FIG. 15 .
  • end cap 22 is the first wall.
  • the surface of the first wall facing away from the first tab 11 is provided with reinforcing ribs 224 .
  • the reinforcing ribs 224 can improve the strength of the first wall, reduce the deformation of the first wall during the process of assembling the battery cell 7, reduce the risk of damage and aging of the first weak portion 2211 due to the deformation of the first wall, and improve Accuracy of pressure relief structure 221 actuation.
  • the first wall is provided with a plurality of reinforcing ribs 224 , and the plurality of reinforcing ribs 224 and the plurality of first weak portions 2211 are alternately arranged along the circumferential direction Y.
  • Reinforcing ribs 224 are provided on both sides of each first weak portion 2211 along the circumferential direction Y.
  • the two adjacent reinforcing ribs 224 can effectively reduce the deformation of the areas on both sides of the first weak portion 2211 and reduce the risk of the first weak portion. 2211 has the risk of damage and aging, and improves the accuracy of the actuation of the pressure relief structure 221.
  • FIG. 17 is a partial cross-sectional schematic view of a battery cell provided by other embodiments of the present application;
  • FIG. 18 is a schematic structural view of the end cap shown in FIG. 17 .
  • end cap 22 is the first wall.
  • the first wall includes a body portion 222 and a protrusion 225 .
  • the protrusion 225 protrudes from a surface of the body portion 222 facing the first pole lug 11 and is connected with the first pole.
  • the tabs 11 are against each other, and the protruding portion 225 is welded to the first tab 11 to form the welding portion 30 .
  • the pressure relief structure 221 is provided on the body part 222.
  • the protruding portion 225 offsets the first pole lug 11 to separate the body portion 222 and the first pole lug 11 by a certain distance.
  • the first tab 11 is not easy to squeeze the body part 222, which can reduce the risk of the body part 222 deforming, thereby reducing the risk of damage and aging of the pressure relief structure 221 due to the deformation of the body part 222. risk and improve the accuracy of actuation of the pressure relief structure 221.
  • the first wall forms a recess 226 at a position corresponding to the protrusion 225 , and the recess 226 is recessed relative to a surface of the body portion 222 facing away from the first tab 11 .
  • the portion of the protruding portion 225 corresponding to the bottom surface of the recessed portion 226 is welded to the first tab 11 to form the welding portion 30 .
  • the thickness of the convex portion 225 can be reduced, the difficulty of welding the convex portion 225 and the first tab 11 is reduced, the heat generated during the welding process is reduced, the risk of the electrode assembly 10 being burned is reduced, and the safety is improved.
  • the plurality of protrusions 225 can stably press and support the first tab 11 , reduce the pressure between the first wall and the first tab 11 , and reduce the deformation of the first tab 11 and the first wall.
  • each of the plurality of protrusions 225 is welded to the first tab 11 .
  • a battery including a plurality of battery cells according to any of the above embodiments.
  • an electrical device including the battery cell of any of the above embodiments, and the battery cell is used to provide electrical energy to the electrical device.
  • the power-consuming device can be any of the aforementioned devices or systems using battery cells.
  • a cylindrical battery cell 7 which includes a housing 20 , an electrode assembly 10 and an electrode terminal 40 .
  • the housing 20 includes a housing 21 and an end cover 22.
  • the housing 21 has an opening, and the end cover 22 is used to cover the opening.
  • the electrode terminal 40 is mounted on the housing 20 and is located on a side of the electrode assembly 10 away from the end cap 22 .
  • the electrode assembly 10 includes a first tab 11 and a second tab 12 with opposite polarities.
  • the first tab 11 is located at an end of the electrode assembly 10 facing the end cap 22
  • the second tab 12 is located at an end of the electrode assembly 10 facing the electrode terminal 40 .
  • the first tab 11 is welded to the end cover 22 to form a plurality of welding parts 30 .
  • the second tab 12 is electrically connected to the electrode terminal 40 .
  • the housing 21 is electrically connected to the first tab 11 through the end cover 22 .
  • the end cover 22 is provided with a pressure relief structure 221.
  • the pressure relief structure 221 includes a plurality of first weak portions 2211 and a second weak portion 2212.
  • the first weak portion 2211 extends along the radial direction of the first wall, the second weak portion 2212 is annular, and a plurality of first weak portions 2211 surrounds the outside of the second weak portion 2212 and is connected to the second weak portion 2212 .
  • the plurality of welding parts 30 and the plurality of first weak parts 2211 are arranged along the circumferential direction of the end cover 22 .

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  • Connection Of Batteries Or Terminals (AREA)

Abstract

本申请实施例提供一种电池单体、电池以及用电装置。电池单体包括外壳和电极组件。外壳包括第一壁。电极组件面向第一壁的一端设有第一极耳，第一极耳焊接于第一壁并形成焊接部。将电极组件的第一极耳与外壳的第一壁直接焊接，即可省去常规的转接部件，提升电池单体的能量密度，还可缩短电极组件与外壳之间的导电路径，减少产热，改善电池单体的充放电性能。本申请实施例可从外壳的外侧将第一壁与第一极耳焊接，可降低焊接产生的金属颗粒进入外壳内部的风险，提高安全性。

Description

电池单体、电池以及用电装置 技术领域
本申请涉及电池技术领域，并且更具体地，涉及一种电池单体、电池以及用电装置。
背景技术
电池单体广泛用于电子设备，例如手机、笔记本电脑、电瓶车、电动汽车、电动飞机、电动轮船、电动玩具汽车、电动玩具轮船、电动玩具飞机和电动工具等等。
如何提高电池单体的能量密度，是电池技术中的一个研究方向。
发明内容
本申请提供了一种电池单体、电池以及用电装置，其能提高电池单体的能量密度。
第一方面，本申请实施例提供了一种电池单体，包括外壳和电极组件。外壳包括第一壁。电极组件面向第一壁的一端设有第一极耳，第一极耳焊接于第一壁并形成焊接部。
上述技术方案中，将电极组件的第一极耳与外壳的第一壁直接焊接，即可省去常规的转接部件，提升电池单体的能量密度，还可缩短电极组件与外壳之间的导电路径，减少产热，改善电池单体的充放电性能。本申请实施例可从外壳的外侧将第一壁与第一极耳焊接，可降低焊接产生的金属颗粒进入外壳内部的风险，提高安全性。
在一些实施例中，第一极耳卷绕设置且包括N圈极耳层，与焊接部相连的极耳层的数量为n，n/N≥0.2。
与焊接部直接相连的极耳层上的电流，可以直接通过焊接部传导至第一壁；而不与焊接部相连的极耳层上的电流，需要先传导至与焊接部直接相连的极耳层，然后才能通过焊接部传导至第一壁。上述技术方案使n/N大于或等于0.2，以使焊接部连接较多的极耳层，减小不与焊接部直接连接的极耳层和焊接部之间的距离，缩短多个极耳层与第一壁之间的导电路径，降低内阻，提高过流能力。
在一些实施例中，n/N≥0.5。
上述技术方案可进一步增多与焊接部连接的极耳层的数量，从而缩短多个极耳层与第一壁之间的导电路径，降低内阻，提高过流能力。
在一些实施例中，焊接部为直线形、V形或弧形。
在一些实施例中，第一壁为圆形。焊接部设置为多个，多个焊接部沿第一壁的 周向间隔布置。
上述技术方案中，多个焊接部可以提高过流能力。在焊接总面积一定时，通过增加焊接部的数量，可以减小单次焊接的产热，降低烧伤电极组件的风险。
在一些实施例中，第一壁设有泄压结构，泄压结构与焊接部间隔设置。
上述技术方案中，泄压结构可以在电池单体热失控时泄放电池单体的内部物质，从而降低电池单体起火、爆炸的风险，提高安全性。将泄压结构与焊接部间隔设置，可以在焊接过程中，降低泄压结构被高温损伤的风险，提高泄压结构的可靠性。
在一些实施例中，第一壁为圆形；泄压结构包括多个第一薄弱部，多个第一薄弱部沿第一壁的周向布置。
上述技术方案中，在电池单体热失控时，第一壁可以在多个第一薄弱部处破裂，以形成泄放通道，从而降低电池单体爆炸的风险。通过设置多个沿第一壁的周向布置的第一薄弱部，可以提高压力泄放的效率。
在一些实施例中，焊接部设置为多个，多个焊接部和多个第一薄弱部沿周向布置。
上述技术方案中，将多个焊接部和多个第一薄弱部沿周向布置，既可以提升第一壁与第一极耳之间的过流面积，还可以利用焊接部之间的空间设置第一薄弱部，提高电池单体的安全性。
在一些实施例中，多个焊接部和多个第一薄弱部沿周向交替布置。
上述技术方案将多个焊接部和多个第一薄弱部均匀分布，从而降低多个焊接部在电池单体震动时受力的差异，并在电池单体热失控时减小电池单体多个位置泄放效率的差异。
在一些实施例中，第一薄弱部包括第一薄弱段和第二薄弱段，第一薄弱段设置为两个，第一薄弱段沿第一壁的径向延伸，两个第一薄弱段沿周向间隔设置。第二薄弱段连接两个第一薄弱部的靠近第一壁的中心的端部。
上述技术方案中，在电池单体热失控时，在电池单体的内部压力下，第一薄弱段和第二薄弱段破裂，两个第一薄弱段和一个第二薄弱段围成的区域向外翻折，以形成泄压通道。泄压通道可以迅速泄放电池单体的内部物质，以降低电池单体爆炸的风险。
在一些实施例中，第一薄弱部沿第一壁的径向延伸。泄压结构还包括环形的第二薄弱部，多个第一薄弱部环绕在第二薄弱部的外侧并连接于第二薄弱部。
在电池单体热失控时，第二薄弱部优先破裂，第二薄弱部围成的区域在高温高压物质的冲击下脱离电池单体；然后，第一薄弱部逐渐破裂，相邻的第一薄弱部之间的扇形区域可以向外翻折，以形成泄压通道。上述技术方案可以增大泄压通道的尺寸，提升电池单体内部物质泄放的效率。
在一些实施例中，第一壁背离第一极耳的表面设有加强筋。
上述技术方案中，加强筋可以提高第一壁的强度，在装配电池单体的过程中可减小第一壁的变形，降低第一薄弱部因第一壁的变形而出现破损、老化的风险，提高泄压结构致动的准确性。
在一些实施例中，第一壁设有多个加强筋，多个加强筋和多个第一薄弱部沿周向交替布置。
上述技术方案中，各第一薄弱部沿周向的两侧均设有加强筋，相邻的两个加强筋可以有效地减小第一薄弱部两侧的区域的变形，降低第一薄弱部出现破损、老化的风险，提高泄压结构致动的准确性。
在一些实施例中，第一壁包括本体部和凸部，凸部凸出于本体部的面向第一极耳的表面并与第一极耳相抵，且凸部焊接于第一极耳并形成焊接部。泄压结构设于本体部。
上述技术方案中，凸部与第一极耳相抵，以将本体部与第一极耳间隔一定的距离。在电池单体的装配过程中，第一极耳不易挤压本体部，这样可以降低本体部变形的风险，从而降低泄压结构因本体部的变形而出现破损、老化的风险，提高泄压结构致动的准确性。
在一些实施例中，第一壁在与凸部相对应的位置形成凹部，凹部相对于本体部的背离第一极耳的表面凹陷。凸部的与凹部的底面相对应的部分焊接于第一极耳并形成焊接部。
上述技术方案中，通过开设凹部，可以减小凸部的厚度，降低凸部与第一极耳焊接的难度，减少焊接过程中的产热，降低电极组件被烧伤的风险，提高安全性。
在一些实施例中，凸部为多个，多个凸部沿第一壁的周向间隔设置。
上述技术方案中，多个凸部可以稳定地抵压和支撑第一极耳，减小第一壁与第一极耳之间的压强，降低第一极耳和第一壁的变形。
在一些实施例中，焊接部被配置为在泄压结构泄放电池单体的内部物质时破裂，以断开第一壁与第一极耳的连接。
上述技术方案中，在电池单体热失控时，第一壁与第一极耳之间的连接在内部压力的作用下断开，降低第一壁在第一极耳的限制下无法翻折的风险，从而及时泄压，提升泄放效率。
在一些实施例中，外壳包括壳体和端盖，壳体具有开口，端盖用于盖合开口。端盖为第一壁。
在一些实施例中，壳体通过端盖电连接于第一极耳。电池单体还包括安装于壳体的电极端子，电极端子位于电极组件的背离端盖的一侧。电极组件在面向电极端子的一端设有第二极耳，第二极耳的极性与第一极耳的极性相反，第二极耳电连接于电极端子。
在上述技术方案中，壳体和电极端子可作为电池单体的两个输出极从而省去一个传统的电极端子，简化电池单体的结构。在多个电池单体装配成组时，壳体可以与汇流部件电连接，这样既可以增大过流面积，还可以使汇流部件的结构设计更为灵活。。
第二方面，本申请实施例提供了一种电池，包括多个第一方面任一实施例提供的电池单体。
第三方面，本申请实施例提供了一种用电装置，包括第二方面的电池，电池用 于提供电能。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对本申请实施例中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1为本申请一些实施例提供的车辆的结构示意图；
图2为本申请一些实施例提供的电池的爆炸示意图；
图3为图2所示的电池模块的爆炸示意图；
图4为本申请一些实施例提供的电池单体的结构示意图；
图5为图4所示的电池单体的爆炸示意图；
图6为图4所示的电池单体的剖视示意图；
图7为图6在方框A处的放大示意图；
图8为本申请一些实施例提供的电池单体的电极组件的结构示意图；
图9为本申请一些实施例提供的电池单体的仰视示意图；
图10为图9所述的端盖的结构示意图；
图11为图10所示的端盖的俯视示意图；
图12为图11沿线B-B作出的剖视示意图；
图13为本申请另一些实施例提供的电池单体的端盖的结构示意图；
图14为图13所示的端盖的另一结构示意图，其中，端盖的被第一薄弱部围成的区域翻折；
图15为本申请另一些实施例提供的电池单体的端盖的结构示意图；
图16为图15所示的端盖的剖视示意图；
图17为本申请另一些实施例提供的电池单体的局部剖视示意图；
图18为图17所示的端盖的结构示意图。
在附图中，附图并未按照实际的比例绘制。
具体实施方式
为使本申请实施例的目的、技术方案和优点更加清楚，下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
除非另有定义，本申请所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同；本申请中在申请的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申请；本申请的说明书和权利要求书 及上述附图说明中的术语“包括”和“具有”以及它们的任何变形，意图在于覆盖不排他的包含。本申请的说明书和权利要求书或上述附图中的术语“第一”、“第二”等是用于区别不同对象，而不是用于描述特定顺序或主次关系。
在本申请中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。
在本申请的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”、“附接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
本申请中术语“和/或”，仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本申请中字符“/”，一般表示前后关联对象是一种“或”的关系。
在本申请的实施例中，相同的附图标记表示相同的部件，并且为了简洁，在不同实施例中，省略对相同部件的详细说明。应理解，附图示出的本申请实施例中的各种部件的厚度、长宽等尺寸，以及集成装置的整体厚度、长宽等尺寸仅为示例性说明，而不应对本申请构成任何限定。
本申请中出现的“多个”指的是两个以上(包括两个)。
本申请中，电池单体可以包括锂离子二次电池单体、锂离子一次电池单体、锂硫电池单体、钠锂离子电池单体、钠离子电池单体或镁离子电池单体等，本申请实施例对此并不限定。电池单体可呈圆柱体、扁平体、长方体或其它形状等，本申请实施例对此也不限定。
本申请的实施例所提到的电池是指包括一个或多个电池单体以提供更高的电压和容量的单一的物理模块。例如，本申请中所提到的电池可以包括电池模块或电池包等。电池一般包括用于封装一个或多个电池单体的箱体。箱体可以避免液体或其他异物影响电池单体的充电或放电。
电池单体包括电极组件和电解液，电极组件包括正极极片、负极极片和隔离件。电池单体主要依靠金属离子在正极极片和负极极片之间移动来工作。正极极片包括正极集流体和正极活性物质层，正极活性物质层涂覆于正极集流体的表面；正极集流体包括正极集流区和凸出于正极集流区的正极极耳，正极集流区涂覆有正极活性物质层，正极极耳的至少部分未涂覆正极活性物质层。以锂离子电池为例，正极集流体的材料可以为铝，正极活性物质层包括正极活性物质，正极活性物质可以为钴酸锂、磷酸铁锂、三元锂或锰酸锂等。负极极片包括负极集流体和负极活性物质层，负极活性物质层涂覆于负极集流体的表面；负极集流体包括负极集流区和凸出于负极集流区的负极极耳，负极集流区涂覆有负极活性物质层，负极极耳的至少部分未涂覆负极活性物质层。负极集流体的材料可以为铜，负极活性物质层包括负极活性物质，负极活性物质可以为碳或硅等。隔离件的材质可以为PP(polypropylene，聚丙烯)或PE (polyethylene，聚乙烯)等。
电池单体还包括外壳，外壳具有容纳腔，电极组件和电解液容纳于容纳腔。外壳可以保护电极组件，降低其他异物影响电极组件的风险。
为了将电极组件产生的电能导出，通常在外壳上设置两个电极端子；两个电极端子分别与正极极片和负极极片电连接，以便于引出电极组件的电能。
为了节省部件，简化电池单体的结构，发明人尝试以外壳作为电池单体的一个电极。具体地，可将外壳电连接于正极极片或负极极片，以使外壳作为电池单体的一个电极，进而节省一个电极端子，简化电池单体的结构。
在相关技术中，外壳通常通过转接部件电连接于极片。然而，转接部件会占用电池单体的内部空间，减小电池单体的能量密度，还会增加与转接部件相关的装配工艺，影响电池单体的成型效率。
鉴于此，本申请实施例提供了一种技术方案，其通过将电极组件的极耳与外壳的壁直接焊接，可省去常规技术中的转接部件，提升电池单体的能量密度，还可缩短电极组件与外壳之间的导电路径，减少产热，改善电池单体的充放电性能。
本申请实施例描述的技术方案适用于电池以及使用电池的用电装置。
用电装置可以是车辆、手机、便携式设备、笔记本电脑、轮船、航天器、电动玩具和电动工具等等。车辆可以是燃油汽车、燃气汽车或新能源汽车，新能源汽车可以是纯电动汽车、混合动力汽车或增程式汽车等；航天器包括飞机、火箭、航天飞机和宇宙飞船等等；电动玩具包括固定式或移动式的电动玩具，例如，游戏机、电动汽车玩具、电动轮船玩具和电动飞机玩具等等；电动工具包括金属切削电动工具、研磨电动工具、装配电动工具和铁道用电动工具，例如，电钻、电动砂轮机、电动扳手、电动螺丝刀、电锤、冲击电钻、混凝土振动器和电刨等等。本申请实施例对上述用电装置不做特殊限制。
以下实施例为了方便说明，以用电装置为车辆为例进行说明。
图1为本申请一些实施例提供的车辆的结构示意图。
如图1所示，车辆1的内部设置有电池2，电池2可以设置在车辆1的底部或头部或尾部。电池2可以用于车辆1的供电，例如，电池2可以作为车辆1的操作电源。
车辆1还可以包括控制器3和马达4，控制器3用来控制电池2为马达4供电，例如，用于车辆1的启动、导航和行驶时的工作用电需求。
在本申请一些实施例中，电池2不仅仅可以作为车辆1的操作电源，还可以作为车辆1的驱动电源，代替或部分地代替燃油或天然气为车辆1提供驱动动力。
图2为本申请一些实施例提供的电池的爆炸示意图。
如图2所示，电池2包括箱体5和电池单体(图2未示出)，电池单体容纳于箱体5内。
箱体5用于容纳电池单体，箱体5可以是多种结构。在一些实施例中，箱体5可以包括第一箱体部5a和第二箱体部5b，第一箱体部5a与第二箱体部5b相互盖合，第一箱体部5a和第二箱体部5b共同限定出用于容纳电池单体的容纳空间5c。第二箱 体部5b可以是一端开口的空心结构，第一箱体部5a为板状结构，第一箱体部5a盖合于第二箱体部5b的开口侧，以形成具有容纳空间5c的箱体5；第一箱体部5a和第二箱体部5b也均可以是一侧开口的空心结构，第一箱体部5a的开口侧盖合于第二箱体部5b的开口侧，以形成具有容纳空间5c的箱体5。当然，第一箱体部5a和第二箱体部5b可以是多种形状，比如，圆柱体、长方体等。
为提高第一箱体部5a与第二箱体部5b连接后的密封性，第一箱体部5a与第二箱体部5b之间也可以设置密封件，比如，密封胶、密封圈等。
假设第一箱体部5a盖合于第二箱体部5b的顶部，第一箱体部5a亦可称之为上箱盖，第二箱体部5b亦可称之为下箱体。
在电池2中，电池单体可以是一个，也可以是多个。若电池单体为多个，多个电池单体之间可串联或并联或混联，混联是指多个电池单体中既有串联又有并联。多个电池单体之间可直接串联或并联或混联在一起，再将多个电池单体构成的整体容纳于箱体5内；当然，也可以是多个电池单体先串联或并联或混联组成电池模块6，多个电池模块6再串联或并联或混联形成一个整体，并容纳于箱体5内。
图3为图2所示的电池模块的爆炸示意图。
在一些实施例中，如图3所示，电池单体7为多个，多个电池单体7先串联或并联或混联组成电池模块6。多个电池模块6再串联或并联或混联形成一个整体，并容纳于箱体内。
电池模块6中的多个电池单体7之间可通过汇流部件实现电连接，以实现电池模块6中的多个电池单体7的并联或串联或混联。
图4为本申请一些实施例提供的电池单体的结构示意图；图5为图4所示的电池单体的爆炸示意图；图6为图4所示的电池单体的剖视示意图；图7为图6在方框A处的放大示意图。
如图4至图7所示，本申请实施例的电池单体7包括外壳20和电极组件10，外壳20包括第一壁20a，电极组件10面向第一壁20a的一端设有第一极耳11，第一极耳11焊接于第一壁20a并形成焊接部30。
外壳20为空心结构，其内部形成用于容纳电极组件10和电解液的容纳腔。外壳20的形状可根据电极组件10的具体形状来确定。比如，若电极组件10为长方体结构，则可选用长方体外壳；若电极组件10为圆柱结构，则可选用圆柱外壳。
外壳20的材质可以是多种，比如，外壳20的材质可以是金属。可选地，外壳20的材质可以是铜、铁、铝、钢、铝合金等。
第一壁20a是外壳20的具有一定厚度的壁，其可以是外壳20的顶壁，也可以是外壳20的底壁，还可以是外壳20的侧壁，本申请实施例对此不作限制。
电极组件10包括极性相反的第一极片和第二极片。第一极片和第二极片中的一者为正极极片，另一者为负极极片。示例性地，电极组件10通过离子在正极极片和负极极片中的嵌入/脱出时的氧化和还原反应来产生电能。
可选地，电极组件10还包括隔离件，隔离件用于将第一极片和第二极片绝缘隔离。
电极组件10可以是由第一极片、隔离件和第二极片通过卷绕形成的卷绕式结构。电极组件10也可以是由第一极片、隔离件和第二极片通过层叠布置形成的叠片式结构。
第一极耳11可为第一极片的未涂覆活性物质层的部分。
本申请实施例对焊接部30的形状、数量以及位置均不作特别地限制。示例性地，焊接部30可为直线形、弧形、V形、圆形、椭圆形、矩形或其它形状。示例性地，焊接部30可以为一个，也可以为多个。
在本申请实施例中，将电极组件10的第一极耳11与外壳20的第一壁20a直接焊接，即可省去常规的转接部件，提升电池单体7的能量密度，还可缩短电极组件10与外壳20之间的导电路径，减少产热，改善电池单体7的充放电性能。本申请实施例可从外壳20的外侧将第一壁20a与第一极耳11焊接，可降低焊接产生的金属颗粒进入外壳20内部的风险，提高安全性。
在一些实施例中，通过激光焊接将第一壁20a焊接于第一极耳11。示例性地，可以在第一壁20a背离第一极耳11的表面照射激光，激光将第一壁20a的一部分和第一极耳11的一部分熔化并形成熔池，熔池凝固后形成焊接部30。
在一些实施例中，外壳20包括壳体21和端盖22，壳体21具有开口，端盖22用于盖合开口。
壳体21是用于配合端盖22以形成电池单体7的内部空腔的部件，形成的内部空腔可以用于容纳电极组件10、电解液以及其他部件。
壳体21和端盖22可以是独立的部件。示例性的，可以于壳体21上设置开口，通过在开口处使端盖22盖合开口，以形成电池单体7的内部空腔。
壳体21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21的形状可以根据电极组件10的具体形状和尺寸大小来确定。壳体21的材质可以是多种，比如，铜、铁、铝、不锈钢、铝合金等，本申请实施例对此不作特殊限制。
端盖22的形状可以与壳体21的形状相适应以配合壳体21。可选地，端盖22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22在受挤压碰撞时就不易发生形变，使电池单体7能够具备更高的结构强度，安全性能也可以有所提高。
壳体21可为一侧开口的结构，端盖22设置为一个并盖合于壳体21的开口。可替代地，壳体21也可为两侧开口的结构，端盖22设置为两个，两个端盖22分别盖合于壳体21的两个开口。
示例性地，端盖22通过焊接、粘接、卡接或其它方式连接于壳体21。
第一壁20a可以是端盖22，也可以是壳体21的壳壁。
在一些实施例中，端盖22为第一壁20a。端盖22直接焊接于第一极耳11并形成焊接部30。
在一些实施例中，壳体21通过端盖22电连接于第一极耳11。示例性地，壳体21焊接于端盖22，以使壳体21和端盖22电连接。
壳体21本身可以作为电池单体7的输出极，从而省去一个传统的电极端子，简 化电池单体7的结构。在多个电池单体7装配成组时，壳体21可以与汇流部件电连接，这样既可以增大过流面积，还可以使汇流部件的结构设计更为灵活。
在一些实施例中，电池单体7还包括安装于壳体21的电极端子40，电极端子40位于电极组件10的背离端盖22的一侧。电极组件10在面向电极端子40的一端设有第二极耳12，第二极耳12的极性与第一极耳11的极性相反，第二极耳12电连接于电极端子40。
第二极耳12可为第二极片的未涂覆活性物质层的部分。
第一极耳11和第二极耳12分别设于电极组件10的两端。
在本实施例中，壳体21和电极端子40可作为电池单体7的两个输出极。
在一些实施例中，壳体21包括与端盖22相对的第二壁211，电极端子40安装于第二壁211。
第二壁211和电极端子40可以作为电池单体7的两个输出极，这样可以简化电池单体7的结构，并保证电池单体7的过流能力。第二壁211和电极端子40位于电池单体7的同一端，这样，在将多个电池单体7装配成组时，汇流部件可以装配到电池单体7的同一侧，这样可以简化装配工艺，提高装配效率。
在一些实施例中，电池单体7为圆柱电池单体。
在一些实施例中，壳体21为圆筒状。
在一些实施例中，壳体21的基体材质和端盖22的基体材质相同，这样可以保证壳体21和端盖22的焊接强度，保证电池单体7的密封性。
图8为本申请一些实施例提供的电池单体的电极组件的结构示意图；图9为本申请一些实施例提供的电池单体的仰视示意图。
请一并参照图7至图9，在一些实施例中，电极组件10为卷绕结构。
在一些实施例中，第一极耳11卷绕设置且包括N圈极耳层111，与焊接部30相连的极耳层111的数量为n，n/N≥0.2。
N和n均为大于1的正整数。
第一极耳11沿卷绕方向W的两端分别为内端11a和外端11b，可选地，本实施例以第一极耳11的内端11a为基准划分极耳层111。
例如，第一极耳11的内端11a为第一个极耳层111的首端，第一个极耳层111的尾端与第一个极耳层111的首端在第一极耳11的径向上对齐，第一个极耳层111环绕电极组件10的中心轴线一圈。对应地，第一个极耳层111的尾端即为第二个极耳层111的首端，以此类推，N个极耳层111沿卷绕方向W首尾相连。在划分极耳层111时，每个极耳层111的首端与第一极耳11的内端11a沿在第一极耳11的径向上对齐。第一极耳11的径向垂直于电极组件的中心轴线并通过中心轴线，可选地，中心轴线平行于第一壁20a的厚度方向。
示例性地，第一极耳11的内端11a和外端11b在第一极耳11的径向上对齐，每一个极耳层111环绕中心轴线一圈。
当然，可替代地，第一极耳11的内端11a和外端11b在第一极耳11的径向上也可以不对齐，这样，最后一个极耳层111环绕中心轴线不足一圈，例如，最后一个 极耳层111可以环绕中心轴线1/4圈、1/3圈、1/2圈、2/3圈或3/4圈。
第一壁和第一极耳11之间的电流主要通过焊接部30传导。焊接部30可以减小第一壁和第一极耳11之间的电阻，提高过流能力。
发明人注意到，与焊接部30直接相连的极耳层111上的电流，可以直接通过焊接部30传导至第一壁；而不与焊接部30相连的极耳层111上的电流，需要先传导至与焊接部30直接相连的极耳层111，然后才能通过焊接部30传导至第一壁，这造成一些极耳层111与第一壁之间的导电路径较长且内阻偏大。
鉴于此，本实施例使n/N大于或等于0.2，以使焊接部30连接较多的极耳层111，减小不与焊接部30直接连接的极耳层111和焊接部30之间的距离，缩短多个极耳层111与第一壁之间的导电路径，降低内阻，提高过流能力。
在一些实施例中，n/N≥0.5。本申请一些实施例进一步增多与焊接部30连接的极耳层111的数量，从而缩短多个极耳层111与第一壁之间的导电路径，降低内阻，提高过流能力。
在一些实施例中，n/N的值可为0.2、0.3、0.4、0.5、0.6、0.7、0.8或0.9。
在一些实施例中，在电极组件10卷绕完成后，第一极耳11大体为柱体状，相邻的两个极耳层111之间留有缝隙。本申请一些实施例可以对第一极耳11进行处理，以减小极耳层111间的缝隙，便于第一极耳11与第一壁连接。例如，本申请一些实施例可对第一极耳11进行揉平处理，以使第一极耳11的端部区域收拢、集合在一起；揉平处理在第一极耳11面向第一壁的一端形成致密的端面，减小极耳层111间的缝隙，便于第一极耳11与第一壁焊接。可替代地，本申请一些实施例也可以在相邻的两圈极耳层111之间填充导电材料，以减小极耳层111间的缝隙。
在一些实施例中，焊接部30为直线形、V形或弧形。
在一些实施例中，第一壁为圆形。焊接部30设置为多个，多个焊接部30沿第一壁的周向Y间隔布置。
焊接部30的数量可根据电池单体7对过流能力的需求确定。例如，焊接部30可以为2个、3个、4个或更多个。
多个焊接部30可以提高过流能力。在焊接总面积一定时，通过增加焊接部30的数量，可以减小单次焊接的产热，降低烧伤电极组件10的风险。
在一些实施例中，第一壁为圆形，焊接部30沿第一壁的径向延伸。
示例性地，第一壁的径向平行于第一极耳11的径向。
沿第一壁的径向延伸的焊接部30可以连接更多的极耳层111，从而缩短多个极耳层111与第一壁之间的导电路径，降低内阻，提高过流能力。
图10为图9所述的端盖的结构示意图；图11为图10所示的端盖的俯视示意图；图12为图11沿线B-B作出的剖视示意图。
请一并参照图9至图12，在一些实施例中，第一壁设有泄压结构221，泄压结构221与焊接部30间隔设置。
泄压结构221对电池单体7的安全性有着重要影响。例如，当发生短路、过充等现象时，可能会导致电池单体7内部发生热失控从而压力骤升。这种情况下通过泄 压结构221致动可以将内部压力向外释放，以防止电池单体7爆炸、起火。
泄压结构221可以是在电池单体7达到一定条件时致动的元件或部件。示例性地，泄压结构221可以是在电池单体7的内部压力或内部温度达到预定阈值时致动以泄放内部压力和/或内部物质的元件或部件。该阈值设计根据设计需求不同而不同。该阈值可能取决于电池单体7中的正极极片、负极极片、电解液和隔离件中一种或几种的材料。
泄压结构221可以采用诸如防爆阀、气阀、泄压阀或安全阀等的形式，并可以具体采用压敏元件或构造，即，当电池单体7的内部压力达到预定阈值时，泄压结构221执行动作或者泄压结构221中设有的薄弱区破裂，从而形成可供内部压力泄放的泄压通道。可替代地，泄压结构221也可采用温敏元件或构造，即当电池单体7的内部温度达到预定阈值时，泄压结构221执行动作，从而形成可供内部压力泄放的泄压通道。可替代地，泄压结构221也可为能够主动致动的部件，示例性地，泄压结构221可以在接收到电池的控制信号时致动。
本申请中所提到的“致动”是指泄压结构221产生动作或被激活至一定的状态，从而使得电池单体7的内部压力和/或内部物质得以被泄放。泄压结构221产生的动作可以包括但不限于：泄压结构221中的至少一部分破裂、破碎、被撕裂或者打开，等等。泄压结构221在致动时，电池单体7的内部的高温高速物质作为排放物会从致动的部位向外排出。以此方式能够在可控压力的情况下使电池单体7发生泄压，从而避免潜在的更严重的事故发生。
泄压结构221可以为一个独立的构件，其通过焊接、粘接或其它方式固定于第一壁。可替代地，泄压结构221也可与第一壁一体成形。
泄压结构221可以在电池单体7热失控时泄放电池单体7的内部物质，从而降低电池单体7起火、爆炸的风险，提高安全性。将泄压结构221与焊接部30间隔设置，可以在焊接过程中，降低泄压结构221被高温损伤的风险，提高泄压结构221的可靠性。
在一些实施例中，第一壁为圆形。泄压结构221包括多个第一薄弱部2211，多个第一薄弱部2211沿第一壁的周向Y布置。
第一薄弱部2211是第一壁的强度相对较小的部分，其是第一壁的易于破裂、破碎、被撕裂或者被打开的部分。示例性地，第一薄弱部2211的强度小于第一壁的靠近第一薄弱部2211的部分的强度。
在一些示例中，可以在第一壁的预定区域开设凹槽、刻痕或其它结构，以减小第一壁局部的强度，进而在第一壁上形成第一薄弱部2211。例如，在第一壁的预定区域进行减薄处理，第一壁的被减薄处理的部分形成第一薄弱部2211。在另一些示例中，可以对第一壁的预定区域进行材料处理，使得该区域的强度弱于其它区域的强度，换言之，该区域即为第一薄弱部2211。
在电池单体7热失控时，第一壁可以在多个第一薄弱部2211处破裂，以形成泄放通道，从而降低电池单体7爆炸的风险。通过设置多个沿第一壁的周向Y布置的第一薄弱部2211，可以提高压力泄放的效率。
在一些实施例中，焊接部30设置为多个，多个焊接部30和多个第一薄弱部2211沿周向Y布置。
多个焊接部30和多个第一薄弱部2211沿周向Y围绕第一壁的中心。本实施例不限定焊接部30和第一薄弱部2211布置的顺序。示例性地，多个焊接部30和多个第一薄弱部2211可沿周向Y交替布置，也可沿周向Y不规则布置。例如，在周向Y上，相邻的两个薄弱部之间的焊接部30的数量可以是一个，也可以是多个。
本申请一些实施例将多个焊接部30和多个第一薄弱部2211沿周向Y布置，既可以提升第一壁与第一极耳11之间的过流面积，还可以利用焊接部30之间的空间设置第一薄弱部2211，提高电池单体7的安全性。
在一些实施例中，多个焊接部30和多个第一薄弱部2211沿周向Y交替布置。
本实施例可以将多个焊接部30和多个第一薄弱部2211均匀分布，从而降低多个焊接部30在电池单体7震动时受力的差异，并在电池单体7热失控时减小电池单体7多个位置泄放效率的差异。
在一些实施例中，第一薄弱部2211沿第一壁的径向延伸。泄压结构221还包括环形的第二薄弱部2212，多个第一薄弱部2211环绕在第二薄弱部2212的外侧并连接于第二薄弱部2212。
本申请实施例对第一薄弱部2211的强度与第二薄弱部2212的强度不作限制。
在电池单体7热失控时，第二薄弱部2212优先破裂，第二薄弱部2212围成的区域在高温高压物质的冲击下脱离电池单体7；然后，第一薄弱部2211逐渐破裂，相邻的第一薄弱部2211之间的扇形区域可以向外翻折，以形成泄压通道。可以增大泄压通道的尺寸，提升电池单体7内部物质泄放的效率。
在一些实施例中，焊接部30被配置为在泄压结构221泄放电池单体7的内部物质时破裂，以断开第一壁与第一极耳11的连接。
在电池单体7热失控时，第一壁与第一极耳11之间的连接在内部压力的作用下断开，降低第一壁在第一极耳11的限制下无法翻折的风险，从而及时泄压，提升泄放效率。
在一些实施例中，第一壁包括平板状的本体部222，本体部222与第一极耳11相抵。本体部222的表面开设有凹槽，以形成第一薄弱部2211和第二薄弱部2212。
本体部222与第一极耳11焊接并形成焊接部30。
焊接部30和薄弱部均形成于平板状的本体部222，可节省第一壁占用的高度空间，提升电池单体7的能量密度。
本体部222为平板状，其为焊接预留的面积充足，可满足过流需求，并能够在焊接时降低定位要求，提升焊接效率。
在一些实施例中，第一壁还包括环绕在本体部222的外侧并凸出于第一壁的外表面的限位部223。第一壁为端盖22，限位部223可用于与壳体21相抵，以避免端盖22过度地插入壳体21。可选地，限位部223焊接于壳体21。
图13为本申请另一些实施例提供的电池单体的端盖的结构示意图；图14为图13所示的端盖的另一结构示意图，其中，端盖的被第一薄弱部围成的区域翻折。
在一些实施例中，端盖22为第一壁。
在一些实施例中，如图13所示，第一薄弱部2211包括第一薄弱段221a和第二薄弱段221b，第一薄弱段221a设置为两个，第一薄弱段221a沿第一壁的径向延伸，第一薄弱段221a沿周向Y间隔设置。第二薄弱段221b连接两个第一薄弱部2211的靠近第一壁的中心的端部。
第一薄弱部2211围成的区域大体为扇形。
如图14所示，在电池单体7热失控时，在电池单体7的内部压力下，第一薄弱段221a和第二薄弱段221b破裂，两个第一薄弱段221a和一个第二薄弱段221b围成的区域向外翻折，以形成泄压通道。泄压通道可以迅速泄放电池单体7的内部物质，以降低电池单体7爆炸的风险。
图15为本申请另一些实施例提供的电池单体的端盖的结构示意图；图16为图15所示的端盖的剖视示意图。
在一些实施例中，端盖22为第一壁。
在一些实施例中，第一壁背离第一极耳11的表面设有加强筋224。
加强筋224可以提高第一壁的强度，在装配电池单体7的过程中可减小第一壁的变形，降低第一薄弱部2211因第一壁的变形而出现破损、老化的风险，提高泄压结构221致动的准确性。
在一些实施例中，第一壁设有多个加强筋224，多个加强筋224和多个第一薄弱部2211沿周向Y交替布置。
各第一薄弱部2211沿周向Y的两侧均设有加强筋224，相邻的两个加强筋224可以有效地减小第一薄弱部2211两侧的区域的变形，降低第一薄弱部2211出现破损、老化的风险，提高泄压结构221致动的准确性。
图17为本申请另一些实施例提供的电池单体的局部剖视示意图；图18为图17所示的端盖的结构示意图。
在一些实施例中，端盖22为第一壁。
如图17和图18所示，在一些实施例中，第一壁包括本体部222和凸部225，凸部225凸出于本体部222的面向第一极耳11的表面并与第一极耳11相抵，且凸部225焊接于第一极耳11并形成焊接部30。泄压结构221设于本体部222。
凸部225与第一极耳11相抵，以将本体部222与第一极耳11间隔一定的距离。在电池单体7的装配过程中，第一极耳11不易挤压本体部222，这样可以降低本体部222变形的风险，从而降低泄压结构221因本体部222的变形而出现破损、老化的风险，提高泄压结构221致动的准确性。
在一些实施例中，第一壁在与凸部225相对应的位置形成凹部226，凹部226相对于本体部222的背离第一极耳11的表面凹陷。凸部225的与凹部226的底面相对应的部分焊接于第一极耳11并形成焊接部30。
通过开设凹部226，可以减小凸部225的厚度，降低凸部225与第一极耳11焊接的难度，减少焊接过程中的产热，降低电极组件10被烧伤的风险，提高安全性。
在一些实施例中，凸部225为多个，多个凸部225沿第一壁的周向间隔设置。
多个凸部225可以稳定地抵压和支撑第一极耳11，减小第一壁与第一极耳11之间的压强，降低第一极耳11和第一壁的变形。
在一些实施例中，多个凸部225均与第一极耳11焊接。
根据本申请的一些实施例，还提供了一种电池，包括多个以上任一实施例的电池单体。
根据本申请的一些实施例，还提供了一种用电装置，包括以上任一实施例的电池单体，电池单体用于为用电装置提供电能。用电装置可以是前述任一应用电池单体的设备或系统。
根据本申请的一些实施例，参照图4至图9，提供了一种圆柱电池单体7，其包括外壳20、电极组件10和电极端子40。外壳20包括壳体21和端盖22，壳体21具有开口，端盖22用于盖合开口。电极端子40安装于外壳20且位于电极组件10的背离端盖22的一侧。
电极组件10包括极性相反的第一极耳11和第二极耳12，第一极耳11位于电极组件10面向端盖22的一端，第二极耳12位于电极组件10面向电极端子40的一端。第一极耳11焊接于端盖22并形成多个焊接部30。第二极耳12电连接于电极端子40。壳体21通过端盖22电连接于第一极耳11。
端盖22设有泄压结构221，泄压结构221包括多个第一薄弱部2211和一个第二薄弱部2212。第一薄弱部2211沿第一壁的径向延伸，第二薄弱部2212为环形，多个第一薄弱部2211环绕在第二薄弱部2212的外侧并连接于第二薄弱部2212。
多个焊接部30和多个第一薄弱部2211沿端盖22的周向布置。
需要说明的是，在不冲突的情况下，本申请中的实施例及实施例中的特征可以相互组合。
最后应说明的是：以上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，或者对其中部分技术特征进行等同替换，但这些修改或者替换，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精神和范围。

Claims (21)

  1. 一种电池单体，包括：
    外壳，包括第一壁；以及
    电极组件，面向所述第一壁的一端设有第一极耳，所述第一极耳焊接于所述第一壁并形成焊接部。
  2. 根据权利要求1所述的电池单体，其中，所述第一极耳卷绕设置且包括N圈极耳层，与所述焊接部相连的所述极耳层的数量为n，n/N≥0.2。
  3. 根据权利要求2所述的电池单体，其中，n/N≥0.5。
  4. 根据权利要求1-3任一项所述的电池单体，其中，所述焊接部为直线形、V形或弧形。
  5. 根据权利要求1-4任一项所述的电池单体，其中，所述第一壁为圆形；所述焊接部设置为多个，多个所述焊接部沿所述第一壁的周向间隔布置。
  6. 根据权利要求1-5任一项所述的电池单体，其中，所述第一壁设有泄压结构，所述泄压结构与所述焊接部间隔设置。
  7. 根据权利要求6所述的电池单体，其中，所述第一壁为圆形；所述泄压结构包括多个第一薄弱部，多个所述第一薄弱部沿所述第一壁的周向布置。
  8. 根据权利要求7所述的电池单体，其中，所述焊接部设置为多个，多个所述焊接部和多个所述第一薄弱部沿所述周向布置。
  9. 根据权利要求8所述的电池单体，其中，多个所述焊接部和多个所述第一薄弱部沿所述周向交替布置。
  10. 根据权利要求7-9任一项所述的电池单体，其中，所述第一薄弱部包括第一薄弱段和第二薄弱段，所述第一薄弱段设置为两个，所述第一薄弱段沿所述第一壁的径向延伸，两个所述第一薄弱段沿所述周向间隔设置；
    所述第二薄弱段连接两个所述第一薄弱部的靠近所述第一壁的中心的端部。
  11. 根据权利要求7-9任一项所述的电池单体，其中，
    所述第一薄弱部沿所述第一壁的径向延伸；
    所述泄压结构还包括环形的第二薄弱部，多个所述第一薄弱部环绕在所述第二薄弱部的外侧并连接于所述第二薄弱部。
  12. 根据权利要求7-12任一项所述的电池单体，其中，所述第一壁背离所述第一极耳的表面设有加强筋。
  13. 根据权利要求12所述的电池单体，其中，所述第一壁设有多个所述加强筋，多个所述加强筋和多个所述第一薄弱部沿所述周向交替布置。
  14. 根据权利要求6-13任一项所述的电池单体，其中，所述第一壁包括本体部和凸部，所述凸部凸出于所述本体部的面向所述第一极耳的表面并与所述第一极耳相抵，且所述凸部焊接于所述第一极耳并形成所述焊接部；
    所述泄压结构设于所述本体部。
  15. 根据权利要求14所述的电池单体，其中，所述第一壁在与所述凸部相对应的位置形成凹部，所述凹部相对于所述本体部的背离所述第一极耳的表面凹陷；
    所述凸部的与所述凹部的底面相对应的部分焊接于所述第一极耳并形成所述焊接部。
  16. 根据权利要求14或15所述的电池单体，其中，所述凸部为多个，多个所述凸部沿所述第一壁的周向间隔设置。
  17. 根据权利要求6-17任一项所述的电池单体，其中，所述焊接部被配置为在所述泄压结构泄放所述电池单体的内部物质时破裂，以断开所述第一壁与所述第一极耳的连接。
  18. 根据权利要求1-17任一项所述的电池单体，其中，所述外壳包括壳体和端盖，所述壳体具有开口，所述端盖用于盖合所述开口；
    所述端盖为所述第一壁。
  19. 根据权利要求18所述的电池单体，其中，
    所述壳体通过所述端盖电连接于所述第一极耳；
    所述电池单体还包括安装于所述壳体的电极端子，所述电极端子位于所述电极组件的背离所述端盖的一侧；
    所述电极组件在面向所述电极端子的一端设有第二极耳，所述第二极耳的极性与所述第一极耳的极性相反，所述第二极耳电连接于所述电极端子。
  20. 一种电池，包括多个根据权利要求1-19中任一项所述的电池单体。
  21. 一种用电装置，包括根据权利要求20所述的电池，所述电池用于提供电能。
PCT/CN2022/111636 2022-08-11 2022-08-11 电池单体、电池以及用电装置 WO2024031501A1 (zh)

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CN215266605U (zh) * 2021-07-30 2021-12-21 宁德时代新能源科技股份有限公司 电池单体、电池及用电设备
CN215988974U (zh) * 2021-08-23 2022-03-08 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
CN216120509U (zh) * 2021-10-20 2022-03-22 宁德时代新能源科技股份有限公司 电池单体、电池和用电设备
CN216213727U (zh) * 2021-09-30 2022-04-05 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
CN114597555A (zh) * 2022-03-28 2022-06-07 远景动力技术(江苏)有限公司 圆柱电池及其制造方法
CN216903232U (zh) * 2022-01-26 2022-07-05 宁德时代新能源科技股份有限公司 泄压装置、电池单体、电池及用电设备

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CN215266605U (zh) * 2021-07-30 2021-12-21 宁德时代新能源科技股份有限公司 电池单体、电池及用电设备
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