Electrode assembly, battery cell, battery and electric device

Abstract

The utility model discloses an electrode assembly, a battery monomer, a battery and a power utilization device. The electrode assembly comprises a first pole piece, a second pole piece and an insulating part. The first pole piece comprises a first current collecting main body and a first active material layer arranged on the surface of the first current collecting main body, one end of the first current collecting main body along a first direction is provided with a first end surface, and the first direction is perpendicular to the thickness direction of the first current collecting main body; the second pole piece and the first pole piece are opposite in polarity. The second pole piece comprises a second current collecting main body and a second active substance layer arranged on the surface of the second current collecting main body, and the first active substance layer is opposite to the second active substance layer. One end of the insulator along the first direction is located between the first active material layer and the second active material layer, and the other end of the insulator along the first direction exceeds the first end face.

Description

Technical Field

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

[0002] Battery monomers are widely used in electronic devices, such as mobile phones, laptop computers, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and electric tools, etc.

[0003] In the development of battery technology, how to improve the reliability of battery cells is a research direction in battery technology. Utility Model Content

[0004] The present application provides an electrode assembly, a battery cell, a battery, and an electrical device, which can improve reliability.

[0005] In a first aspect, the present application provides an electrode assembly, which includes a first pole piece, a second pole piece and an insulating member. The first pole piece includes a first current collector and a first active material layer disposed on the surface of the first current collector, and one end of the first current collector along a first direction has a first end face, and the first direction is perpendicular to the thickness direction of the first current collector. The second pole piece has an opposite polarity to the first pole piece. The second pole piece includes a second current collector and a second active material layer disposed on the surface of the second current collector, and the first active material layer is opposite to the second active material layer. One end of the insulating member along the first direction is located between the first active material layer and the second active material layer, and the other end of the insulating member along the first direction exceeds the first end face.

[0006] The insulating member can separate the burr on the first end face from the second pole piece, thereby reducing the risk of the burr being connected to the second pole piece, reducing the possibility of thermal runaway caused by short circuit, and improving the reliability of the battery cell. By providing the insulating member, the over-design of the size of the negative electrode active material layer in the first direction can be reduced, and the energy density can be improved; even if ion precipitation occurs in the electrode assembly due to insufficient negative electrode active material layer, the insulating member can block the precipitated metal, reduce the risk of the metal connecting the first active material layer to the second active material layer, and reduce the possibility of thermal runaway caused by short circuit.

[0007] In some embodiments, the second active material layer includes a main body region and a thinned region, the thinned region is located on a side of the main body region close to the first end face in the first direction, and the thickness of at least a portion of the thinned region is less than the thickness of the main body region. In the thickness direction, a portion of the insulating member is located between the first active material layer and the thinned region.

[0008] By providing the thinning area, the pressure on the edge of the second active material layer can be reduced during the rolling process of the second active material layer, reducing the risk of cracking of the second current collector. The space between the first active material layer and the thinning area is used to arrange the insulating member, which can not only improve the space utilization rate, but also reduce stress concentration.

[0009] In some embodiments, the insulating member is connected to the surface of the thinned area away from the second current collecting body. Connecting the insulating member to the thinned area can limit the relative movement between the insulating member and the thinned area, reducing the risk of the insulating member failing to block burrs due to deviation.

[0010] In some embodiments, in the direction from the second current collector to the second active material layer, the insulating member does not extend beyond the surface of the main region away from the second current collector. The embodiments of the present application can reduce the extra space occupied by the insulating member in the thickness direction, improve space utilization, and reduce the risk of the insulating member squeezing the first pole piece when the electrode assembly expands.

[0011] In some embodiments, in the first direction, the insulating member is spaced from the main body region so that the main body region and the insulating member do not overlap in the thickness direction, thereby improving space utilization. The insulating member is not likely to block the transmission of ions between the main body region and the first active material layer, thereby reducing the capacity loss of the battery cell.

[0012] In some embodiments, in the first direction, one end of the thinning region away from the main region exceeds the first end surface and does not exceed the insulating member. Since the insulating member can block the burrs on the first end surface, the thinning region can extend and exceed the first end surface, thereby increasing the active material content of the electrode assembly.

[0013] In some embodiments, the first electrode is a negative electrode and the second electrode is a positive electrode. The thinning area of ​​the positive polarity exceeds the first end face, so that the thinning area can provide more active ions and improve the capacity of the battery cell. Even if the first active material layer has ion precipitation due to the part of the thinning area exceeding the first end face, the insulating member can separate the first active material layer from the thinning area to a certain extent, thereby reducing the risk of short circuit.

[0014] In some embodiments, an end of the thinned region away from the main region is flush with an end of the insulating member extending beyond the first end surface, thereby reducing the amount of insulating member used and improving the energy density of the battery cell.

[0015] In some embodiments, the second current collector has a second end surface at one end close to the first end surface along the first direction. In the first direction, the insulating member extends beyond the second end surface. The insulating member can separate the burr on the second end surface from the first pole piece, thereby reducing the risk of the burr being connected to the first pole piece, reducing the possibility of thermal runaway caused by short circuit, and improving the reliability of the battery cell.

[0016] In some embodiments, the second active material layer has a third end surface at one end close to the first end surface along the first direction. The second end surface and the third end surface are flush. The embodiment of the present application can reduce the difference in size between the second current collecting body and the second active material layer along the first direction, reduce the waste of the second current collecting body, and improve the energy density.

[0017] In some embodiments, a second active material layer is disposed on both sides of the second current collecting body. The electrode assembly includes two insulating members, and the two insulating members are respectively connected to the two second active material layers. The two insulating members can separate the two second active material layers from the burrs on the first end surface, thereby reducing the risk of short circuit and improving reliability.

[0018] In some embodiments, each insulating member extends beyond the second current collecting body, and the portions of the two insulating members extending beyond the second current collecting body are connected. The connection of the two insulating members can reduce the risk of the insulating members falling off the second pole piece and improve reliability.

[0019] In some embodiments, the second current collector has a second end face and a fourth end face that are arranged to intersect, and the second end face is located at one end of the second current collector close to the first end face along the first direction. The two insulating members extend beyond the fourth end face and are connected. The insulating member can cover the burrs on the fourth end face, thereby reducing the risk of short circuit and improving reliability. By extending the insulating member, the embodiment of the present application can also reduce the risk of not being able to separate the first end face and the second active material layer due to assembly error.

[0020] In some embodiments, in the first direction, the absolute value of the difference between the size of the first active material layer and the size of the second active material layer is less than or equal to 2 mm. By providing an insulating member, the embodiment of the present application can reduce the excessive design requirements for the negative electrode active material layer, reduce the size difference between the first active material layer and the second active material layer, thereby reducing the waste of active materials and improving the energy density of the battery cell.

[0021] In some embodiments, the first electrode is a negative electrode and the second electrode is a positive electrode. In the first direction, one end of the second active material layer close to the insulating member exceeds the first active material layer. The second active material layer can provide more active ions, thereby increasing the capacity of the battery cell. Even if ions are precipitated from the first active material layer, the insulating member can separate the precipitated metal from the second active material layer to a certain extent, thereby reducing the risk of short circuit.

[0022] In some embodiments, the electrode assembly further comprises a separator, which is used to separate the first pole piece from the second pole piece. In the first direction, the insulating member does not extend beyond the separator, thereby reducing the extra space occupied by the insulating member in the first direction.

[0023] In some embodiments, the insulating member is configured to allow ions to pass through the insulating member, so that the ions can be inserted and extracted back and forth between the first active material layer and the second active material layer, thereby increasing the capacity of the battery cell.

[0024] In some embodiments, the porosity of the insulating member is 30%-40%. The insulating member has a higher porosity to reduce the resistance of ions passing through the insulating member.

[0025] In a second aspect, the present application provides a battery cell, which includes a housing and an electrode assembly provided by any embodiment of the first aspect, wherein the electrode assembly is accommodated in the housing.

[0026] In a third aspect, the present application provides a battery comprising a plurality of battery cells provided according to any embodiment of the second aspect.

[0027] In a fourth aspect, the present application provides an electrical device, comprising a battery provided according to any embodiment of the third aspect, and the battery is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The features, advantages and technical effects of exemplary embodiments of the present application will be described below with reference to the accompanying drawings.

[0029] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0030] Figure 2 An exploded schematic diagram of a battery provided in some embodiments of the present application;

[0031] Figure 3 An exploded schematic diagram of a battery cell provided in some embodiments of the present application;

[0032] Figure 4 A schematic top view of an electrode assembly provided in some embodiments of the present application;

[0033] Figure 5 A partial cross-sectional schematic diagram of an electrode assembly provided in some embodiments of the present application;

[0034] Figure 6 A schematic diagram of a second pole piece and an insulating member of an electrode assembly provided in some embodiments of the present application in a flattened state;

[0035] Figure 7 for Figure 6 A schematic cross-sectional view taken along the AA direction;

[0036] Figure 8 for Figure 6 A schematic partial cross-sectional view taken along the BB direction;

[0037] Fig. 9A partial cross-sectional schematic diagram of an electrode assembly provided in some other embodiments of the present application;

[0038] Fig.10 A schematic diagram of a second pole piece and an insulating member of an electrode assembly provided in some embodiments of the present application in a flattened state;

[0039] Fig.11 for Fig.10 Schematic cross-sectional view along the CC direction.

[0040] The following are the descriptions of the reference numerals:

[0041] 1. Vehicle; 2. Battery; 3. Controller; 4. Motor; 5. Box; 5a. First box part; 5b. Second box part; 5c. Accommodation space; 6. Battery cell;

[0042] 10. electrode assembly; 20. housing; 21. shell; 22. end cap; 30. electrode terminal;

[0043] 11. first pole piece; 111. first current collecting body; 111a. first end surface; 112. first active material layer; 113. first pole ear;

[0044] 12, second pole piece; 121, second current collecting body; 121a, second end face; 121b, fourth end face; 122, second active material layer; 1221, main body region; 1222, thinning region; 122a, third end face; 123, second pole ear;

[0045] 13. Isolation parts; 14. Insulation parts;

[0046] V, winding direction; Y, thickness direction; Z, first direction. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0048] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0049] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0050] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0051] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0052] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0053] The term "plurality" used in the present application refers to two or more (including two).

[0054] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0055] Battery cells may include but are not limited to lithium ion battery cells, sodium ion battery cells, sodium lithium ion battery cells, lithium metal battery cells, sodium metal battery cells, lithium sulfur battery cells, magnesium ion battery cells, nickel metal hydride battery cells, nickel cadmium battery cells, lead storage battery cells, etc.

[0056] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell or a battery cell of other shapes. The prismatic battery cell includes a square shell battery cell, a blade-shaped battery cell, a polygonal battery, such as a hexagonal battery, etc. There is no particular limitation in the present application.

[0057] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0058] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0059] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are accommodated in the case.

[0060] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0061] In some embodiments, the battery may be an energy storage device, which includes an energy storage container, an energy storage cabinet, and the like.

[0062] A battery cell generally includes an electrode assembly and a housing, and the electrode assembly is contained in the housing. The electrode assembly includes a positive electrode and a negative electrode. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and removed back and forth between the positive electrode and the negative electrode. In some embodiments, the electrode assembly also includes a separator, which is arranged between the positive electrode and the negative electrode to prevent the positive and negative electrodes from short-circuiting and allow active ions to pass through.

[0063] The shell is used to encapsulate the electrode assembly and electrolyte and other components. The shell can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell) or an aluminum-plastic film.

[0064] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector. The negative electrode may be a negative electrode sheet, which may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.

[0065] During the preparation of the electrode sheet (positive electrode sheet or negative electrode sheet), it is usually necessary to cut (such as the electrode ear die cutting process) to form the required size and shape. However, after cutting, the current collector is prone to burrs at the cutting position; during the charging and discharging process of the battery cell, the burrs may pierce the separator and connect the positive and negative electrodes, causing a short circuit risk and affecting the reliability of the battery cell.

[0066] In view of this, an embodiment of the present application provides a technical solution, which provides an insulating member on the pole piece to block the burrs on the end surface of the current collector, thereby reducing the risk of the burrs conducting the positive and negative electrodes and improving the reliability of the battery cell.

[0067] The electrode assembly described in the embodiments of the present application is applicable to a battery cell, a battery, and an electrical device using the battery.

[0068] The battery disclosed in the embodiments of the present application can be used in an electrical device that uses the battery as a power source or in various energy storage systems that use the battery as an energy storage element. The electrical device can be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, and the like. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric car toy, an electric ship toy, and an electric airplane toy, and the like, and the spacecraft can include an airplane, a rocket, a space shuttle, and a spacecraft, and the like.

[0069] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0070] Figure 1 A schematic diagram of the structure of a vehicle provided for some embodiments of the present application.

[0071] like Figure 1 As shown, a battery 2 is disposed inside the vehicle 1, and the battery 2 may be disposed 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.

[0072] The vehicle 1 may further include a controller 3 and a motor 4 , wherein the controller 3 is used to control the battery 2 to supply power to the motor 4 , for example, to meet the power requirements of starting, navigating, and driving the vehicle 1 .

[0073] In some embodiments of the present application, the battery 2 can not only serve as an operating power source for the vehicle 1, but also serve as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0074] Figure 2 Schematic diagram of an explosion of a battery provided in some embodiments of the present application. Figure 2 As shown, the battery 2 includes a box body 5 and a battery cell 6 , and the battery cell 6 is accommodated in the box body 5 .

[0075] The box 5 is used to accommodate the battery cell 6, and the box 5 can be of various structures. In some embodiments, the box 5 can include a first box portion 5a and a second box portion 5b, the first box portion 5a and the second box portion 5b cover each other, and the first box portion 5a and the second box portion 5b jointly define a storage space 5c for accommodating the battery cell. The second box portion 5b can be a hollow structure with one end open, the first box portion 5a is a plate-like structure, and the first box portion 5a covers the open side of the second box portion 5b to form a box 5 with a storage space 5c; the first box portion 5a and the second box portion 5b can also be hollow structures with one side open, and the open side of the first box portion 5a covers the open side of the second box portion 5b to form a box 5 with a storage space 5c. Of course, the first box portion 5a and the second box portion 5b can be of various shapes, such as a cylinder, a cuboid, etc.

[0076] In order to improve the sealing performance after the first box body part 5a and the second box body part 5b are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body part 5a and the second box body part 5b.

[0077] Assuming that the first box body portion 5a covers the top of the second box body portion 5b, the first box body portion 5a can also be called an upper box cover, and the second box body portion 5b can also be called a lower box.

[0078] In the battery 2, the battery cell 6 can be one or more. If there are more than one battery cell 6, the battery cells 6 can be connected in series, in parallel or in mixed connection. Mixed connection means that the battery cells 6 are both connected in series and in parallel. The battery cells 6 can be directly connected in series, in parallel or in mixed connection, and then the whole formed by the battery cells 6 is accommodated in the box 5; of course, the battery cells can also be connected in series, in parallel or in mixed connection to form a battery module, and then the battery modules are connected in series, in parallel or in mixed connection to form a whole, and then accommodated in the box 5.

[0079] Illustratively, a battery cell may be the smallest unit constituting a battery.

[0080] Figure 3 An exploded schematic diagram of a battery cell provided in some embodiments of the present application.

[0081] like Figure 3 As shown, in some embodiments, the battery cell 6 includes a housing 20 and an electrode assembly 10 accommodated in the housing 20 .

[0082] The electrode assembly 10 includes a positive electrode and a negative electrode. During the charge and discharge process of the battery cell 6, active ions (such as lithium ions) are inserted and removed back and forth between the positive electrode and the negative electrode. Optionally, the electrode assembly 10 also includes a separator disposed between the positive electrode and the negative electrode, which can reduce the risk of short circuit between the positive and negative electrodes while allowing active ions to pass through.

[0083] The housing 20 is used to encapsulate the electrode assembly 10 and the electrolyte and other components. The housing 20 can be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing 20), or an aluminum-plastic film.

[0084] In some embodiments, the housing 20 includes a shell 21 and an end cover 22 , the shell 21 has an opening, and the end cover 22 is used to cover the opening.

[0085] The housing 21 is a component used to cooperate with the end cover 22 to form an internal cavity of the battery cell 6. The formed internal cavity can be used to accommodate the electrode assembly 10, electrolyte and other components.

[0086] The housing 21 and the end cap 22 may be independent components. For example, an opening may be provided on the housing 21, and the end cap 22 may cover the opening to form an internal cavity of the battery cell 6.

[0087] The shell 21 can be in various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism shape, etc. Specifically, the shape of the shell 21 can be determined according to the specific shape and size of the electrode assembly 10. The shell 21 can be made of various materials, for example, the material of the shell 21 includes but is not limited to copper, iron, aluminum, stainless steel, aluminum alloy, aluminum-plastic film, steel-plastic film, etc.

[0088] The shape of the end cap 22 can be adapted to the shape of the shell 21 to match the shell 21. The material of the end cap 22 can be the same as or different from the material of the shell 21. Optionally, the end cap 22 can be made of a material with a certain hardness and strength (for example, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.), so that the end cap 22 is not easily deformed when squeezed and collided, so that the battery cell 6 can have a higher structural strength and the reliability performance can also be improved.

[0089] The end cover 22 is connected to the housing 21 by welding, bonding, clamping or other methods.

[0090] The housing 21 may be open at one end or at both ends. In some examples, the housing 21 may be a structure with an opening at one end, and an end cap 22 is provided and covers the housing 21. In other examples, the housing 21 may be a structure with openings at both ends, and two end caps 22 are provided, and the two end caps 22 cover the two openings of the housing 21 respectively.

[0091] In some embodiments, the battery cell 6 includes an electrode terminal 30 . The electrode terminal 30 is electrically connected to the electrode assembly 10 to output or input electrical energy of the battery cell 6 .

[0092] In some embodiments, the battery cell 6 further includes an electrolyte contained in the housing 20. The electrolyte plays a role in conducting ions between the positive and negative electrodes and can be in liquid, gel or solid state.

[0093] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0094] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0095] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane sulfone, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0096] In some embodiments, the gel electrolyte includes a polymer as an electrolyte skeleton network and an ionic liquid-lithium salt.

[0097] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0098] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, and the like.

[0099] As an example, the inorganic solid electrolyte can be an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0100] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0101] Figure 4 A schematic top view of an electrode assembly provided in some embodiments of the present application; Figure 5 A schematic partial cross-sectional view of an electrode assembly provided in some embodiments of the present application.

[0102] Reference Figure 4 and Figure 5 The electrode assembly 10 of the embodiment of the present application includes a first pole piece 11 and a second pole piece 12 with opposite polarities.

[0103] Exemplarily, one of the first pole piece 11 and the second pole piece 12 is a positive pole piece, and the other is a negative pole piece.

[0104] In some embodiments, the positive electrode sheet may include a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector.

[0105] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material layer is disposed on any one or both of the two facing surfaces of the positive electrode current collector.

[0106] As an example, the positive electrode current collector may be carbon, metal foil or composite current collector. For example, as the metal foil, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, titanium, silver surface treated aluminum or stainless steel, etc. may be used. The composite current collector may include a polymer material base and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0107] As an example, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may include at least one of the following materials: a lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds. The positive electrode active material may also use other traditional materials that can be used as a positive electrode active material layer of a battery. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3Mn 1 / 3 O2 (also referred to as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi 0.80 Co 0.15 Al 0.05 O2) and its modified compounds, etc.

[0108] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.

[0109] As an example, the negative electrode current collector can be a metal foil, a foamed metal or a composite current collector. For example, as a metal foil, aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, nickel or titanium with a silver surface treatment can be used. The foamed metal can be a nickel foam, a copper foam, an aluminum foam, an alloy foam, or a carbon foam. The composite current collector can include a polymer material base and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0110] As an example, the negative electrode active material layer includes a negative electrode active material. The negative electrode active material may adopt a negative electrode active material for a battery cell that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may include at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may include at least one of elemental tin, tin oxide compounds, and tin alloys. The negative electrode active material of the present application may also use other traditional materials that can be used as negative electrode active materials for batteries. These negative electrode active materials may be used alone or in combination of two or more.

[0111] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0112] In some embodiments, the electrode assembly 10 further includes a separator 13, which is used to separate the first electrode sheet 11 from the second electrode sheet 12. The separator 13 can reduce the risk of short circuit between the positive and negative electrodes, while allowing active ions to pass through.

[0113] In some embodiments, the separator 13 includes a separator. The separator of the present application can be any known porous separator with good chemical stability and mechanical stability.

[0114] As an example, the main material of the separator may include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator 13 may be a separate component located between the positive and negative electrodes, or it may be attached to the surface of the positive and negative electrodes.

[0115] In some embodiments, the separator 13 is a solid electrolyte. The solid electrolyte is disposed between the positive electrode sheet and the negative electrode sheet, and plays the role of transmitting ions and isolating the positive and negative electrodes.

[0116] In some embodiments, the electrode assembly 10 is a wound structure. Exemplarily, the first pole piece 11 and the second pole piece 12 are both strip-shaped structures, and the first pole piece 11, the separator 13 and the second pole piece 12 are wound into a wound structure.

[0117] In some embodiments, the electrode assembly 10 is a laminate structure.

[0118] As an example, a plurality of the first pole pieces 11 and a plurality of the second pole pieces 12 may be provided respectively, and the plurality of first pole pieces 11 and the plurality of second pole pieces 12 may be alternately stacked.

[0119] As an example, a plurality of first pole sheets 11 may be provided, and the second pole sheet 12 may be folded to form a plurality of stacked folded segments, with one first pole sheet 11 being sandwiched between adjacent folded segments.

[0120] As an example, the first pole piece 11 and the second pole piece 12 are both folded to form a plurality of stacked folded segments.

[0121] As an example, a plurality of spacers 13 may be provided, each spacer 13 being provided between any adjacent first pole pieces 11 or second pole pieces 12 .

[0122] As an example, the spacer 13 may be disposed continuously, and disposed between any adjacent first pole pieces 11 or second pole pieces 12 by folding or winding.

[0123] In some embodiments, the shape of the electrode assembly 10 can be cylindrical, flat, or polygonal.

[0124] Figure 6 A schematic diagram of a second pole piece and an insulating member of an electrode assembly provided in some embodiments of the present application in a flattened state; Figure 7 for Figure 6 A schematic cross-sectional view taken along the AA direction; Figure 8 for Figure 6 Schematic diagram of the local section taken along direction BB.

[0125] Reference Figures 4 to 8 , an embodiment of the present application provides an electrode assembly 10, which includes a first pole piece 11 and a second pole piece 12 with opposite polarities.

[0126] The first electrode sheet 11 includes a first current collecting body 111 and a first active material layer 112 disposed on a surface of the first current collecting body 111 .

[0127] Exemplarily, the first current collector 111 includes two first surfaces arranged opposite to each other along its thickness direction, and the first active material layer 112 may be arranged on one first surface, or on both first surfaces. The first active material layer 112 may be arranged on the first surface as a whole. Alternatively, a portion of the first active material layer 112 may also be arranged at other locations, for example, the first pole piece 11 also includes a first pole ear 113 connected to the first current collector 111, and a portion of the first active material layer 112 may be arranged at the root of the first pole ear 113 close to the first current collector 111.

[0128] The second electrode sheet 12 includes a second current collecting body 121 and a second active material layer 122 disposed on a surface of the second current collecting body 121 .

[0129] Exemplarily, the second current collector 121 includes two second surfaces arranged opposite to each other along its thickness direction, and the second active material layer 122 may be arranged on one second surface, or on both second surfaces. The second active material layer 122 may be arranged on the second surface as a whole. Alternatively, a portion of the second active material layer 122 may also be arranged at other locations, for example, the second pole piece 12 also includes a second pole ear 123 connected to the second current collector 121, and a portion of the second active material layer 122 may be arranged at the root of the second pole ear 123 close to the second current collector 121.

[0130] In some examples, the first electrode sheet 11 is a positive electrode sheet, and the second electrode sheet 12 is a negative electrode sheet; the positive electrode current collector may include a first current collector body 111, and the first active material layer 112 is a positive electrode active material layer, and the negative electrode current collector may include a second current collector body 121, and the second active material layer 122 is a negative electrode active material layer. In other examples, the first electrode sheet 11 is a negative electrode sheet, and the second electrode sheet 12 is a positive electrode sheet; the positive electrode current collector may include a second current collector body 121, and the second active material layer 122 is a positive electrode active material layer, and the negative electrode current collector may include a first current collector body 111, and the first active material layer 112 is a negative electrode active material layer.

[0131] In some embodiments, one end of the first current collecting body 111 along a first direction Z has a first end surface 111 a , and the first direction Z is perpendicular to a thickness direction Y of the first current collecting body 111 .

[0132] Exemplarily, the first current collecting body 111 has a relatively small thickness, the first end surface 111a is relatively small in the thickness direction Y of the first current collecting body 111, and the first end surface 111a can be approximately a line. Optionally, the thickness of the first current collecting body 111 is 2 μm-30 μm. Optionally, the thickness of the first current collecting body 111 is 5 μm-15 μm.

[0133] Exemplarily, at least a portion of the first end surface 111 a is formed during a cutting process of the first pole piece 11 .

[0134] Exemplarily, the first end surface 111 a connects the two first surfaces.

[0135] In some embodiments, the first active material layer 112 is opposite to the second active material layer 122. During the charge and discharge process of the battery cell 6, active ions (eg, lithium ions) are intercalated and extracted between the first active material layer 112 and the second active material layer 122.

[0136] In some embodiments, the electrode assembly 10 further includes an insulating member 14. One end of the insulating member 14 along the first direction Z is located between the first active material layer 112 and the second active material layer 122, and the other end of the insulating member 14 along the first direction Z exceeds the first end surface 111a.

[0137] The insulating member 14 may be connected to the first pole piece 11 , may be connected to the second pole piece 12 , or may be connected to the isolating member 13 .

[0138] Exemplarily, in the thickness direction Y of the first current collecting body 111, at least a portion of the first end surface 111a overlaps with the insulating member 14. In the first direction Z, two ends of the insulating member 14 are respectively located on both sides of the first end surface 111a.

[0139] The number of the insulating member 14 may be one or more.

[0140] The insulating member 14 can separate the burr on the first end surface 111a from the second pole piece 12, thereby reducing the risk of the burr being connected to the second pole piece 12, reducing the possibility of thermal runaway caused by short circuit, and improving the reliability of the battery cell 6. By providing the insulating member 14, the over-design of the size of the negative electrode active material layer in the first direction Z can be reduced, and the energy density can be improved; even when the electrode assembly 10 has ion precipitation (such as lithium precipitation) due to insufficient negative electrode active material layer, the insulating member 14 can block the precipitated metal, reduce the risk of the metal connecting the first active material layer 112 and the second active material layer 122, and reduce the possibility of thermal runaway caused by short circuit.

[0141] In some embodiments, the electrode assembly 10 further includes a separator 13, which is used to separate the first pole piece 11 from the second pole piece 12. During the operation of the battery cell 6, when the separator 13 cannot separate the first end face 111a from the second pole piece 12 due to heat shrinkage, the insulating member 14 can separate the first end face 111a from the second pole piece 12 to reduce the risk of short circuit.

[0142] In some embodiments, the insulating member 14 is connected to the second pole piece 12 .

[0143] The insulating member 14 can be connected to the second pole piece 12 in a variety of ways. For example, the insulating member 14 can be connected to the second pole piece 12 by bonding; alternatively, the insulating member 14 can be connected to the second pole piece 12 by attachment instead of bonding.

[0144] Connecting the insulating member 14 to the second pole piece 12 can limit the relative movement between the insulating member 14 and the second pole piece 12 , thereby reducing the risk that the insulating member 14 cannot block the burrs due to deviation.

[0145] In some embodiments, the first pole piece 11 further includes a first pole tab 113 , and the first pole tab 113 is connected to the first current collecting body 111 .

[0146] In some examples, the first current collecting body 111 and the first pole tab 113 may be an integrally formed structure; in other examples, the first pole tab 113 and the first current collecting body 111 may be formed independently and connected by welding or other means.

[0147] The number of the first electrode tab 113 may be one or more.

[0148] In some embodiments, the first pole tab 113 is integrally formed with the first current collector 111. For example, the first pole tab 113 can be formed by a die-cutting process; during the forming process of the first pole piece 11, a portion of the first pole piece 11 is removed by the die-cutting process to form the protruding first pole tab 113.

[0149] In some embodiments, the first electrode tab 113 extends outward along the first direction Z from the first end surface 111 a .

[0150] In some embodiments, the second current collecting body 121 has a second end surface 121a at one end along the first direction Z. For example, the second end surface 121a may be located at one end of the second current collecting body 121 along the first direction Z close to the first end surface 111a, or at one end of the second current collecting body 121 along the first direction Z away from the first end surface 111a.

[0151] Exemplarily, at least a portion of the second end surface 121 a is formed during a cutting process of the second pole piece 12 .

[0152] In some embodiments, the second pole piece 12 further includes a second pole tab 123 , and the second pole tab 123 is connected to the second current collecting body 121 .

[0153] In some examples, the second current collecting body 121 and the second pole tab 123 may be an integrally formed structure; in other examples, the second pole tab 123 and the second current collecting body 121 may be formed independently and connected by welding or other means.

[0154] The number of the second electrode tab 123 may be one or more.

[0155] In some embodiments, the second pole tab 123 is integrally formed with the second current collector 121. For example, the second pole tab 123 can be formed by a die-cutting process; during the forming process of the second pole piece 12, a portion of the second pole piece 12 is removed by the die-cutting process to form a protruding second pole tab 123.

[0156] In some embodiments, the second electrode tab 123 extends outward along the first direction Z from the second end surface 121 a.

[0157] In some embodiments, the second active material layer 122 includes a main body region 1221 and a thinned region 1222, the thinned region 1222 is located on one side of the main body region 1221 close to the first end surface 111a in the first direction Z, and the thickness of at least part of the thinned region 1222 is less than the thickness of the main body region 1221. In the thickness direction Y, a portion of the insulating member 14 is located between the first active material layer 112 and the thinned region 1222.

[0158] Exemplarily, one end of the thinned region 1222 close to the main region 1221 is directly connected to the main region 1221. In some examples, the thickness of the end of the thinned region 1222 close to the main region 1221 is less than the thickness of the end of the main region 1221 close to the thinned region 1222, and a step is formed at the connection between the thinned region 1222 and the main region 1221. In other examples, the thickness of the end of the thinned region 1222 close to the main region 1221 is equal to the thickness of the end of the main region 1221 close to the thinned region 1222.

[0159] Exemplarily, the main body region 1221 is substantially a structure of equal thickness, and the average thickness of the thinned region 1222 is less than the thickness of the main body region 1221 .

[0160] Exemplarily, the insulating member 14 may be connected to the thinned region 1222 , may be connected to the first active material layer 112 , and may be connected to the isolation member 13 .

[0161] For example, in the thickness direction Y, the insulating member 14 may overlap with the main body region 1221 or may not overlap with the main body region 1221 .

[0162] For example, in the first direction Z, an end of the thinning region 1222 away from the main region 1221 may extend beyond the first end surface 111 a or may not extend beyond the first end surface 111 a.

[0163] For example, in the first direction Z, one end of the thinned region 1222 away from the main region 1221 may extend beyond the insulating member 14 or may not extend beyond the insulating member 14 .

[0164] During the forming process of the second pole piece 12, the second active material layer 122 can be rolled to increase the compaction density of the second active material layer 122. In the embodiment of the present application, by providing the thinning area 1222, the pressure on the edge of the second active material layer 122 can be reduced, and the risk of cracking of the second current collector 121 can be reduced. The space between the first active material layer 112 and the thinning area 1222 is used to arrange the insulating member 14, which can not only improve the space utilization rate, but also reduce stress concentration.

[0165] In some embodiments, the thickness of one end of the thinning region 1222 close to the main region 1221 is equal to the thickness of one end of the main region 1221 close to the thinning region 1222. The thickness of the thinning region 1222 gradually decreases in a direction away from the main region 1221. The thickness of the thinning region 1222 changes smoothly, thereby reducing the risk of forming steps on the second active material layer 122 and reducing stress concentration.

[0166] In some embodiments, the insulating member 14 is connected to the surface of the thinned area 1222 away from the second current collecting body 121. Connecting the insulating member 14 to the thinned area 1222 can limit the relative movement between the insulating member 14 and the thinned area 1222, reducing the risk of the insulating member 14 failing to block burrs due to deviation.

[0167] In some embodiments, in the direction from the second current collecting body 121 to the second active material layer 122 , the insulating member 14 does not extend beyond the surface of the body region 1221 away from the second current collecting body 121 .

[0168] The embodiment of the present application can reduce the extra space occupied by the insulating member 14 in the thickness direction Y, improve space utilization, and reduce the risk of the insulating member 14 squeezing the first pole piece 11 when the electrode assembly 10 expands.

[0169] In some embodiments, in the first direction Z, the insulating member 14 is spaced apart from the main body region 1221 so that the main body region 1221 and the insulating member 14 do not overlap in the thickness direction Y, thereby improving space utilization. The insulating member 14 is not likely to block the transmission of ions between the main body region 1221 and the first active material layer 112, thereby reducing the capacity loss of the battery cell 6.

[0170] In some embodiments, the thickness of the end of the thinned region 1222 away from the main region 1221 is t1, the thickness of the main region 1221 is t2, the thickness of the insulating member 14 is t3, and t3≤t2-t1.

[0171] The insulating member 14 has a relatively small thickness to reduce the space additionally occupied by the insulating member 14 in the thickness direction Y and to reduce the pressure applied by the insulating member 14 to the first active material layer 112 when the electrode assembly 10 expands.

[0172] In some embodiments, the dimension W of the connection area between the insulating member 14 and the thinning area 1222 along the first direction Z is 0.1 mm-5 mm. W is limited to be greater than or equal to 0.1 mm to increase the connection area between the insulating member 14 and the thinning area 1222 and reduce the risk of the insulating member 14 falling off. W is limited to be less than or equal to 5 mm, which can reduce the amount of the insulating member 14 and reduce the blocking of the insulating member 14 to active ions. Optionally, W is 1 mm-3 mm.

[0173] In some embodiments, in the first direction Z, one end of the thinned region 1222 away from the main region 1221 exceeds the first end surface 111 a.

[0174] Since the insulating member 14 can block the burrs on the first end surface 111 a , the thinned area 1222 can extend beyond the first end surface 111 a , thereby increasing the active material content of the electrode assembly 10 .

[0175] In some embodiments, in the first direction Z, one end of the thinned region 1222 away from the main region 1221 does not exceed the insulating member 14 , thereby reducing the risk of conduction between the thinned region 1222 and the first pole piece 11 .

[0176] In some embodiments, the first electrode 11 is a negative electrode, and the second electrode 12 is a positive electrode.

[0177] The thinned area 1222 has a smaller thickness. Under the same area, the thinned area 1222 provides fewer active ions than the main area 1221. In the embodiment of the present application, the positive thinned area 1222 is made to extend beyond the first end surface 111a, so that the thinned area 1222 can provide more active ions and improve the capacity of the battery cell 6. Even if the first active material layer 112 has ion precipitation due to the thinned area 1222 extending beyond the first end surface 111a, the insulating member 14 can separate the first active material layer 112 from the thinned area 1222 to a certain extent, thereby reducing the risk of short circuit.

[0178] In other embodiments, the first electrode 11 is a positive electrode, and the second electrode 12 is a negative electrode. The negative thinning area 1222 exceeds the first end surface 111a, and the thinning area 1222 can provide embedding space for more active ions, thereby reducing the risk of ion precipitation.

[0179] In some embodiments, one end of the thinned area 1222 away from the main area 1221 is flush with one end of the insulating member 14 beyond the first end surface 111a. The embodiment of the present application can reduce the amount of the insulating member 14 and improve the energy density of the battery cell 6.

[0180] In some embodiments, the second active material layer 122 is disposed on both sides of the second current collecting body 121. The electrode assembly 10 includes two insulating members 14, and the two insulating members 14 are connected to the two second active material layers 122, respectively.

[0181] The two insulating members 14 can separate the two second active material layers 122 from the burrs on the first end surface 111 a , thereby reducing the risk of short circuit and improving reliability.

[0182] In some embodiments, each insulating member 14 extends beyond the second current collecting body 121 , and portions of two insulating members 14 extending beyond the second current collecting body 121 are connected.

[0183] The two insulating members 14 are connected, which can reduce the risk of the insulating member 14 falling off from the second pole piece 12 and improve reliability.

[0184] Exemplarily, two insulating members 14 may be attached to the second pole piece 12 from both sides.

[0185] In some embodiments, the second current collecting body 121 has a second end surface 121a and a fourth end surface 121b intersecting each other, and the second end surface 121a is located at one end of the second current collecting body 121 close to the first end surface 111a along the first direction Z. The two insulating members 14 extend beyond the fourth end surface 121b and are connected.

[0186] The insulating member 14 can cover the burrs on the fourth end surface 121b, thereby reducing the risk of short circuit and improving reliability. By extending the insulating member 14, the embodiment of the present application can also reduce the risk of not being able to separate the first end surface 111a and the second active material layer 122 due to assembly error.

[0187] In some embodiments, there are two fourth end surfaces 121b, and the two fourth end surfaces 121b are respectively connected to two ends of the second end surface 121a. Exemplarily, the second end surface 121a connects the two second surfaces, and the fourth end surface 121b connects the two second surfaces.

[0188] In some embodiments, the electrode assembly 10 is a winding structure. Optionally, the first direction Z may be parallel to the winding axis of the electrode assembly 10. The first pole piece 11 and the second pole piece 12 are wound along a winding direction V.

[0189] Optionally, the two fourth end surfaces 121 b may be located at two ends of the second current collecting body 121 along the winding direction V, respectively.

[0190] The short circuit risk can be reduced by providing the insulating member 14. Specifically, when the first pole piece 11 and the second pole piece 12 are misaligned due to the winding process accuracy, the insulating member 14 can isolate the first pole piece 11 and the second pole piece 12, thereby reducing the short circuit risk.

[0191] In some embodiments, in the winding direction V, both ends of the insulating member 14 extend beyond the first pole piece 11, and both ends of the insulating member 14 extend beyond the second pole piece 12. After the insulating member 14, the first pole piece 11, and the second pole piece 12 are flattened, the length of the insulating member 14 is greater than the length of the first pole piece 11, and the length of the insulating member 14 is greater than the length of the second pole piece 12.

[0192] In some embodiments, the electrode assembly 10 further includes a separator 13 for separating the first electrode sheet 11 from the second electrode sheet 12. The insulating member 14 does not extend beyond the separator 13 in the first direction Z, thereby reducing the extra space occupied by the insulating member 14 in the first direction Z.

[0193] The insulating member 14 can also support the spacer 13 from the inside, reducing the risk of the spacer 13 being wrinkled or folded.

[0194] In some embodiments, the first pole piece 11 , the isolating member 13 and the second pole piece 12 are wound together. In the winding direction V, both ends of the insulating member 14 do not extend beyond the isolating member 13 .

[0195] For example, Figure 4 As shown, the positive direction of the winding direction V is counterclockwise, and the negative direction of the winding direction V is clockwise. In the positive direction of the winding direction V, the insulating member 14 does not exceed the tail end of the isolating member 13; in the negative direction of the winding direction V, the insulating member 14 does not exceed the head end of the isolating member 13.

[0196] The isolation member 13 can restrain the insulating member 14 , maintain the fit between the insulating member 14 and the second pole piece 12 , and reduce the risk of the insulating member 14 falling off the second pole piece 12 .

[0197] In some embodiments, in the first direction Z, an absolute value of a difference between a size of the first active material layer 112 and a size of the second active material layer 122 is less than or equal to 2 mm.

[0198] Exemplarily, the size of the first active material layer 112 along the first direction Z is D1, and the size of the second active material layer 122 along the first direction Z is D2. D1-D2 is -2 mm, -1 mm, 0 mm, 1 mm or 2 mm.

[0199] By providing the insulating member 14 , the embodiment of the present application can reduce the excessive design requirements for the negative electrode active material layer, reduce the size difference between the first active material layer 112 and the second active material layer 122 , thereby reducing the waste of active materials and improving the energy density of the battery cell 6 .

[0200] In some examples, the first electrode 11 is a negative electrode, and the second electrode 12 is a positive electrode. D1-D2≥-2mm, the first active material layer 112 can provide an embedding space for active ions, and even if ions are precipitated from the first active material layer 112, the insulating member 14 can separate the precipitated metal from the second active material layer 122 to a certain extent, thereby reducing the risk of short circuit. D1-D2≤2mm, can reduce the waste of negative active material and improve the energy density of the battery cell 6.

[0201] In some embodiments, the first electrode sheet 11 is a negative electrode sheet, and the second electrode sheet 12 is a positive electrode sheet. In the first direction Z, one end of the second active material layer 122 close to the insulating member 14 exceeds the first active material layer 112. The second active material layer 122 can provide more active ions, thereby increasing the capacity of the battery cell 6. Even if ions are precipitated from the first active material layer 112, the insulating member 14 can separate the precipitated metal from the second active material layer 122 to a certain extent, thereby reducing the risk of short circuit.

[0202] In some embodiments, D1 is equal to D2.

[0203] In some embodiments, the first electrode sheet 11 is a negative electrode sheet, and the second electrode sheet 12 is a positive electrode sheet. In the first direction Z, one end of the first active material layer 112 away from the first end surface 111 a exceeds the second active material layer 122 .

[0204] In some embodiments, the first electrode sheet 11 is a negative electrode sheet, and the second electrode sheet 12 is a positive electrode sheet. Compared with the solution of coating an insulating coating on the surface of the second current collector 121, the embodiment of the present application uses an insulating member 14 to improve the utilization rate of the second current collector 121, and coats more second active material layer 122, thereby increasing the capacity. The insulating member 14 can be attached to the second active material layer 122, and the insulating member 14 can share space with the second active material layer 122 in the first direction Z, thereby improving space utilization.

[0205] In some embodiments, the insulating member 14 is configured to allow ions to pass through the insulating member 14 , so as to be intercalated and extracted back and forth between the first active material layer 112 and the second active material layer 122 , thereby increasing the capacity of the battery cell 6 .

[0206] The insulating member 14 has ion conductivity and insulating properties.

[0207] In some embodiments, the porosity of the insulating member 14 is 30%-40%. The insulating member 14 has a high porosity to reduce the resistance of ions passing through the insulating member 14 .

[0208] Exemplarily, the porosity of the insulating member 14 is 30%, 32%, 34%, 35%, 36%, 38% or 40%.

[0209] In some embodiments, the porosity of the insulating member 14 is less than the porosity of the isolating member 13. Compared with the isolating member 13, the insulating member 14 is less likely to shrink, thereby improving the insulation effect.

[0210] In some embodiments, the air permeability of the insulating member 14 is 110 (sec / 100cc)-210 (sec / 100cc). Exemplarily, the air permeability of the insulating member 14 is 110 (sec / 100cc), 120 (sec / 100cc), 130 (sec / 100cc), 150 (sec / 100cc), 170 (sec / 100cc), 190 (sec / 100cc) or 210 (sec / 100cc).

[0211] The insulating member 14 has high air permeability, thereby improving the cycle performance and reliability of the battery cell 6 .

[0212] For example, the porosity of the insulating member 14, the air permeability of the insulating member 14, and the porosity of the spacer 13 all have well-known meanings in the art and can be measured using known methods. For example, they can all be tested with reference to standard GB / T36363-2018.

[0213] In some embodiments, the thickness of the insulating member 14 is 7 μm-30 μm. Optionally, the thickness of the insulating member 14 is 4 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 20 μm, 25 μm or 30 μm. Limiting the thickness of the insulating member 14 to be greater than or equal to 7 μm can reduce the risk of the insulating member 14 being pierced by burrs and improve reliability. Limiting the thickness of the insulating member 14 to be less than or equal to 30 μm can reduce the space and weight occupied by the insulating member 14 and reduce the loss of energy density of the battery cell 6.

[0214] In some embodiments, the insulating member 14 is rectangular in a flattened state.

[0215] In some embodiments, the width of the insulating member 14 is 1 mm-20 mm in the first direction Z. Optionally, the width of the insulating member 14 is 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 8 mm, 10 mm, 12 mm, 15 mm, 18 mm or 20 mm.

[0216] In some embodiments, the insulating member 14 includes a colloid including at least one of ethylene and copolymers thereof, polyolefins, polyesters, polyurethanes, polyamides, styrene and block copolymers thereof.

[0217] The colloid has a high bonding strength and is not easy to fall off from the main body of the first pole piece 11 .

[0218] Optionally, the colloid may be a hot melt colloid. The insulating member 14 may be a hot melt adhesive film.

[0219] Optionally, during the production process of the second pole piece 12 , colloid may be directly coated on the second pole piece 12 , and the colloid is cured to form the insulating member 14 .

[0220] In other embodiments, the insulating member 14 includes a substrate layer and an adhesive layer, and the substrate layer is connected to the second pole piece 12 through the adhesive layer. The substrate layer can improve the strength of the insulating member 14 and reduce the deformation of the insulating member 14 during the attachment process. The adhesive layer can adhere the substrate layer to the second pole piece 12, reducing the risk of the substrate layer falling off from the second pole piece 12.

[0221] In some embodiments, the substrate layer includes at least one of polyethylene terephthalate (PET), polypropylene, polyethylene, and block copolymers thereof.

[0222] In some embodiments, the adhesive layer includes at least one of polyacrylate, styrene-butadiene rubber, polyisobutylene, or butyl rubber.

[0223] In some embodiments, the electrode assembly 10 includes two insulating members 14, each of which includes a substrate layer and an adhesive layer. The adhesive layers of the two insulating members 14 are bonded. Optionally, the insulating member 14 is a pressure-sensitive adhesive tape.

[0224] In some embodiments, the battery cell 6 includes an electrolyte contained within the housing 20. The insulator 14 remains stable in the electrolyte.

[0225] Exemplarily, after soaking in the electrolyte for 1000 hours, the peel strength between the insulating member 14 and the second active material layer 122 is greater than or equal to 2N / m. Optionally, after soaking in the electrolyte for 1000 hours, the peel strength between the insulating member 14 and the second active material layer 122 is 15N / m-200N / m.

[0226] In some embodiments, the insulating member 14 has good insulation properties, the insulating member 14 will not break down under a voltage of 200 V, and the resistance of the insulating member 14 is greater than or equal to 9999 megohms.

[0227] Fig. 9 A partial cross-sectional schematic diagram of an electrode assembly provided in some other embodiments of the present application; Fig.10 A schematic diagram of a second pole piece and an insulating member of an electrode assembly provided in some embodiments of the present application in a flattened state, wherein a portion of the second pole piece covered by the insulating member is shown by a dotted line; Fig.11 for Fig.10 Schematic cross-sectional view along the CC direction.

[0228] Reference Figures 9 to 11In some embodiments, the second current collecting body 121 has a second end surface 121 a at one end thereof close to the first end surface 111 a along the first direction Z. In the first direction Z, the insulating member 14 exceeds the second end surface 121 a.

[0229] The insulating member 14 can separate the burr on the second end surface 121 a from the first pole piece 11 , thereby reducing the risk of the burr being electrically connected to the first pole piece 11 , reducing the possibility of thermal runaway caused by a short circuit, and improving the reliability of the battery cell 6 .

[0230] In some embodiments, the second active material layer 122 has a third end surface 122a at one end close to the first end surface 111a along the first direction Z. The second end surface 121a and the third end surface 122a are flush.

[0231] Exemplarily, the third end surface 122 a is disposed at one end of the thinning region 1222 along the first direction Z away from the main region 1221 .

[0232] The embodiment of the present application can reduce the size difference between the second current collecting body 121 and the second active material layer 122 along the first direction Z, reduce the waste of the second current collecting body 121, and improve the energy density.

[0233] In some embodiments, the second end surface 121 a may not extend beyond the first active material layer 112 and the first end surface 111 a in the first direction Z. The portion of the insulating member 14 extending beyond the second end surface 121 a may block burrs of the first end surface 111 a.

[0234] In some embodiments, the first end surface 111 a and the second end surface 121 a are flush.

[0235] In some embodiments, two insulating members 14 are attached to the first pole piece 11. The two insulating members 14 extend beyond the second end surface 121a and are connected. The two insulating members 14 can cover the burrs on the second end surface 121a, thereby reducing the risk of the burrs being connected to the first pole piece 11, reducing the possibility of thermal runaway caused by short circuit, and improving the reliability of the battery cell 6.

[0236] In some embodiments, the two insulating members 14 may completely cover the second end surface 121a, or may only cover a portion of the second end surface 121a. For example, the second pole tab 123 is led out from the second end surface 121a, and the two insulating members 14 are connected and cover the area of ​​the second end surface 121a where the second pole tab 123 is not led out in the first direction Z.

[0237] In some embodiments, the second pole tab 123 passes between the two insulating members 14. The two insulating members 14 support the root of the second pole tab 123 close to the second current collector 121, reducing the risk of the second pole tab 123 being inserted between the first pole piece 11 and the second pole piece 12 when being bent, thereby reducing the risk of short circuit and improving reliability.

[0238] In some embodiments, the second pole piece 12 includes a plurality of second pole tabs 123 , and in the winding direction V, the plurality of second pole tabs 123 are arranged at intervals.

[0239] According to some embodiments of the present application, the present application further provides a battery cell, which includes a housing and an electrode assembly according to any of the above embodiments, wherein the electrode assembly is accommodated in the housing.

[0240] According to some embodiments of the present application, the present application also provides a battery, comprising a plurality of battery cells according to any one of the above embodiments.

[0241] According to some embodiments of the present application, the present application further provides an electric device, comprising a battery cell of any of the above embodiments, the battery cell is used to provide electric energy for the electric device. The electric device can be any of the above equipment or systems using the battery cell.

[0242] Reference Figures 4 to 8 The present embodiment provides an electrode assembly 10, which includes a first electrode sheet 11, a second electrode sheet 12, a separator 13 and an insulating member 14. The first electrode sheet 11 is a negative electrode sheet, and the second electrode sheet 12 is a positive electrode sheet. The separator 13 is used to separate the first electrode sheet 11 from the second electrode sheet 12.

[0243] The first electrode sheet 11 includes a first current collector and a first active material layer 112. The first current collector includes a first current collector body 111 and a first electrode tab 113. The first current collector body 111 has a first end surface 111a at one end along a first direction Z. The first electrode tab 113 extends from the first end surface 111a. The first direction Z is perpendicular to a thickness direction Y of the first current collector body 111. At least a portion of the first active material layer 112 is disposed on a surface of the first current collector body 111.

[0244] The second electrode sheet 12 includes a second current collector and a second active material layer 122. The second current collector includes a second current collector body 121 and a second electrode tab 123. The second current collector body 121 has a second end surface 121a at one end close to the first end surface 111a along the first direction Z. The second electrode tab 123 extends from the second end surface 121a. At least part of the second active material layer 122 is disposed on the surface of the second current collector body 121.

[0245] The second active material layer 122 includes a main body region 1221 and a thinning region 1222, wherein the thinning region 1222 is located on one side of the main body region 1221 close to the second end surface 121a in the first direction Z, and the thickness of at least part of the thinning region 1222 is less than the thickness of the main body region 1221. Both the main body region 1221 and the thinning region 1222 are coated on the second current collecting body 121.

[0246] At least a portion of the insulating member 14 is connected to the thinned region 1222 and is located between the thinned region 1222 and the first active material layer 112. In the first direction Z, one end of the insulating member 14 is spaced from the main region 1221, and the other end exceeds the first end surface 111a.

[0247] The insulator 14 is configured to allow ions to pass therethrough.

[0248] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An electrode assembly, characterized in that: include: A first pole piece, comprising a first current collecting body and a first active material layer disposed on a surface of the first current collecting body, wherein one end of the first current collecting body along a first direction has a first end surface, and the first direction is perpendicular to a thickness direction of the first current collecting body; A second pole piece, having a polarity opposite to that of the first pole piece, the second pole piece comprising a second current collecting body and a second active material layer disposed on a surface of the second current collecting body, the first active material layer being opposite to the second active material layer; An insulating member, wherein one end of the insulating member along the first direction is located between the first active material layer and the second active material layer, and the other end of the insulating member along the first direction exceeds the first end surface.

2. The electrode assembly according to claim 1, characterized in that: The second active material layer comprises a main body region and a thinning region, wherein the thinning region is located on a side of the main body region close to the first end surface in the first direction, and the thickness of at least a part of the thinning region is smaller than the thickness of the main body region; In the thickness direction, a portion of the insulating member is located between the first active material layer and the thinned region.

3. The electrode assembly according to claim 2, characterized in that: The insulating member is connected to a surface of the thinned region facing away from the second current collecting body.

4. The electrode assembly according to claim 2 or 3, characterized in that: In a direction from the second current collecting body to the second active material layer, the insulating member does not extend beyond a surface of the main region away from the second current collecting body.

5. The electrode assembly according to claim 2, characterized in that: In the first direction, the insulating member is spaced apart from the main body region.

6. The electrode assembly according to claim 2, characterized in that: In the first direction, one end of the thinned region away from the main region exceeds the first end surface and does not exceed the insulating member.

7. The electrode assembly according to claim 6, characterized in that: The first pole piece is a negative pole piece, and the second pole piece is a positive pole piece.

8. The electrode assembly according to claim 6, characterized in that: An end of the thinned region away from the main region is flush with an end of the insulating member extending beyond the first end surface.

9. The electrode assembly according to claim 1, characterized in that: The second current collecting body has a second end surface at one end thereof close to the first end surface along the first direction; In the first direction, the insulating member exceeds the second end surface.

10. The electrode assembly according to claim 9, characterized in that: The second active material layer has a third end surface at one end thereof close to the first end surface along the first direction; The second end surface is flush with the third end surface.

11. The electrode assembly according to claim 1, characterized in that: The second active material layer is disposed on both sides of the second current collecting body; The electrode assembly includes two insulating members, and the two insulating members are respectively connected to two second active material layers.

12. The electrode assembly according to claim 11, characterized in that: Each of the insulating members extends beyond the second current collecting body, and portions of two insulating members extending beyond the second current collecting body are connected.

13. The electrode assembly according to claim 11 or 12, characterized in that: The second current collecting body has a second end face and a fourth end face that are intersectingly arranged, and the second end face is located at an end of the second current collecting body close to the first end face along the first direction; The two insulating members extend beyond the fourth end surface and are connected.

14. The electrode assembly according to claim 1, characterized in that In the first direction, an absolute value of a difference between a size of the first active material layer and a size of the second active material layer is less than or equal to 2 mm.

15. The electrode assembly according to claim 14, characterized in that: The first pole piece is a negative pole piece, and the second pole piece is a positive pole piece; In the first direction, one end of the second active material layer close to the insulating member exceeds the first active material layer.

16. The electrode assembly according to claim 1, characterized in that The electrode assembly further includes a separator, which is used to separate the first pole piece from the second pole piece; In the first direction, the insulating member does not extend beyond the isolating member.

17. The electrode assembly according to claim 1, characterized in that The insulator is configured to allow ions to pass therethrough.

18. The electrode assembly according to claim 1, characterized in that The porosity of the insulating member is 30%-40%.

19. A battery cell, characterized in that: include: shell; The electrode assembly according to any one of claims 1 to 18 is accommodated in the housing.

20. A battery, characterized in that: The invention comprises a plurality of battery cells according to claim 19.

21. An electrical device, characterized in that: A battery according to claim 20, for providing electrical energy.

Images