Battery cells, battery devices and electrical equipment

Abstract

This application discloses a battery cell, a battery device, and an electrical appliance. The battery cell includes a casing and an electrode assembly. The casing has a receiving space and a first wall, which is located at the bottom of the receiving space in the direction of gravity. The electrode assembly includes multiple anode plates, multiple cathode plates, and a separator. The anode plates and cathode plates are stacked alternately in sequence. The end of the anode plate near the first wall extends beyond the end of the cathode plate near the first wall. The separator includes a main body section and a first bent section. The main body section is disposed between adjacent anode and cathode plates. The first bent section is connected to two adjacent main body sections located on both sides of the anode plate and is located on the side of the main body section near the first wall. The particle size of the anode particles on the anode plates is larger than the pore diameter of the separator. The battery cell, battery device, and electrical appliance of this application can improve the reliability of the battery cell.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a battery cell, a battery device, and an electrical appliance. Background Technology

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. In this context, electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the automotive industry's sustainable development. And for electric vehicles, battery technology is a crucial factor in their development.

[0003] In the development of battery technology, improving the performance of battery devices is an issue that cannot be ignored. Battery devices typically consist of multiple individual cells; therefore, the reliability of these individual cells during use directly affects the performance of the entire battery device. Improving the reliability of individual cells is a crucial technical problem that urgently needs to be solved in the development of battery technology. Summary of the Invention

[0004] This application provides a battery cell, a battery device, and an electrical appliance that can improve the reliability of the battery cell.

[0005] In a first aspect, a battery cell is provided, including a casing and an electrode assembly. The casing has a receiving space and a first wall, which is located at the bottom of the receiving space in the direction of gravity. The electrode assembly is housed in the receiving space and includes a plurality of anode plates, a plurality of cathode plates, and a separator. The anode plates and cathode plates are stacked alternately in sequence. The end of the anode plate near the first wall extends beyond the end of the cathode plate near the first wall. The separator includes a main body segment and a first bent segment. The main body segment is disposed between adjacent anode plates and cathode plates. The first bent segment is connected to two adjacent main body segments located on both sides of the anode plate and is located on the side of the main body segment near the first wall. The particle size φ1 of the anode particles on the anode plates is larger than the pore diameter φ2 of the separator.

[0006] In the technical solution of this application embodiment, the separator can cover the anode plate from its bottom, and the particle size of the anode particles on the anode plate is larger than the pore diameter of the separator. Even if the anode particles fall off, they cannot pass through the separator, thereby preventing them from falling onto the outer casing. This effectively prevents the anode particles on the anode plate, especially the conductive material therein, from directly contacting the outer casing, thus reducing the risk of the anode plate becoming conductive with the outer casing, reducing the risk of the outer casing becoming charged and corroded, and improving the reliability of the battery cell. In addition, since the bottom of the anode plate extends beyond the bottom of the cathode plate, the bottom of the cathode plate is also covered, thereby reducing the risk of the cathode plate becoming conductive with the outer casing, reducing the risk of the outer casing becoming charged and corroded, and further improving the reliability of the battery cell.

[0007] In some embodiments of the first aspect, the particle size φ1 of the anode particles on the anode electrode satisfies: 8μm≤φ1≤37μm, and the pore diameter φ2 of the separator satisfies: 50nm≤φ2≤300nm.

[0008] In the technical solution of this application embodiment, regarding the diameter φ1 of the anode particles, on the one hand, the diameter φ1 of the anode particles is set to be less than or equal to 37μm. During the charging and discharging process, the small-diameter particles can quickly embed and / or de-embed, improving the discharge rate of the battery, while reducing the stress during the battery expansion process and improving the cycle life of the battery cell. In addition, the small gap between the small-diameter particles can improve the energy density. On the other hand, setting the diameter φ1 of the anode particles to be greater than or equal to 8μm can avoid the particle size from causing a sharp increase in specific surface area, reducing the degree of side reaction with the electrolyte, thereby improving the cycle stability of the battery cell. Regarding the pore diameter φ2 of the separator, on the one hand, setting the pore diameter φ2 of the separator to be less than or equal to 300nm can prevent various particles on the electrode from passing through the pores of the separator, reducing the risk of current conduction between the positive and negative electrodes or between the electrode and other components such as the casing. In addition, it can reduce the risk of short circuits caused by the penetration of metal dendrites such as lithium dendrites, thereby improving the overall reliability of the battery cell. On the other hand, setting the pore diameter φ2 of the separator to be greater than or equal to 50nm can ensure that the separator has a sufficient size for ions to pass through while avoiding blockage due to excessively small pores, thereby improving the overall cycle life of the battery cell.

[0009] In some embodiments of the first aspect, the anode electrode has an adhesive, the ratio R of the adhesive content to the anode particle content satisfies: 0.5% ≤ R ≤ 1.2%.

[0010] In the technical solution of this application embodiment, the binder content is set within this range. On the one hand, it can avoid insufficient particle bonding strength on the anode electrode, and reduce phenomena such as powder shedding and separation of the electrode during coating, rolling and other processes. On the other hand, it can avoid excessive binder content from crowding out the volume of active material, increasing the energy density of the battery cell. It can also avoid excessive binder from clogging the pores of the electrode, improving the effectiveness of electrolyte wetting and ion transport, and improving the overall charge and discharge performance of the battery cell.

[0011] In some embodiments of the first aspect, the main body segment extends along a first direction and away from the first bend segment, and the two ends of the main body segment along the first direction extend outward beyond the two ends of the anode plate along the first direction, the first direction being perpendicular to the first wall.

[0012] In the technical solution of this application embodiment, the length of the main body segment in the first direction is greater than the length of the anode electrode, and both ends extend beyond the anode electrode. This allows the orthographic projection of the anode electrode along its thickness direction to be located at the orthographic projection of the first bending segment along its thickness direction. The sides of adjacent anode and cathode electrodes that are close to each other in the thickness direction are completely separated by the main body segment, thereby reducing the risk of direct contact between the anode and cathode electrodes leading to electronic conduction and causing internal short circuits. In addition, during the assembly of the electrode assembly, the portions of the main body segments on both sides of the anode electrode that extend beyond the anode electrode along the first direction, as well as the corresponding first bending segments connected to the main body segments, are offset to a certain extent in the electrode stacking direction. This causes some adjacent first bending segments to overlap, and the portions of adjacent main body segments that extend beyond the anode electrode are offset to the bottom of the cathode electrode adjacent to the anode electrode. This also isolates the bottom of the cathode electrode from the outer casing, preventing trace amounts of conductive material falling off the cathode electrode from contacting the outer casing. At the same time, it reduces the risk of the outer casing becoming charged and corroded due to conduction between the anode and cathode electrodes and the outer casing, further improving the reliability of the battery cell.

[0013] In some embodiments of the first aspect, the spacer further includes a second bent section; the second bent section is connected to two adjacent main body sections located on both sides of the cathode electrode, the second bent section being located on the side of the main body section away from the first wall.

[0014] In the technical solution of this application embodiment, the second bending segment is located on the side of the main body segment away from the first wall, that is, the second bending segment is located at the top of the main body segment. The second bending segment connects two adjacent main body segments from the top of the cathode electrode, so that the main body segment, the second bending segment and the main body segment connected in sequence cover the top of the cathode electrode and isolate the top of the cathode electrode from the outer shell, thereby reducing the risk of the cathode electrode directly contacting the outer shell or short circuit caused by misalignment between the cathode and anode electrodes due to stacking misalignment.

[0015] In some embodiments of the first aspect, the cathode electrode is provided with the anode electrode on both sides along the stacking direction; the separator further includes an epitaxial section and a third bending section, the epitaxial section being located on the side of the outermost anode electrode away from the cathode electrode, the third bending section being connected to the adjacent epitaxial section and the main body section on both sides of the outermost anode electrode, and the third bending section being located on the side of the epitaxial section near the first wall.

[0016] In the technical solution of this application embodiment, by setting an extension section and a third bending section on the outermost anode plate, the bottom of all anode plates in the electrode assembly are separated from the outer casing, further preventing conductive material falling off the anode plate from accumulating and contacting the outer casing under the action of gravity, reducing the risk of corrosion of the outer casing due to the anode plate being connected to the outer casing. At the same time, the extension section can prevent the outermost anode plate along the stacking direction from overlapping with the outer casing, thus preventing short circuits and further improving the reliability of the battery cell.

[0017] In some embodiments of the first aspect, the epitaxial segment extends along a first direction and away from the third bend, with both ends of the epitaxial segment extending outward beyond both ends of the anode sheet along the first direction, the first direction being perpendicular to the first wall.

[0018] In the technical solution of this application embodiment, the length of the epitaxial segment in the first direction is greater than the length of the outermost anode plate, and both ends extend beyond the anode plate, so that the orthographic projection of the anode plate along its thickness direction is located within the orthographic projection of the epitaxial segment along its thickness direction. The side of the anode plate that is close to the outer casing in the thickness direction is completely separated by the epitaxial segment, thereby reducing the risk of the outermost anode plate directly contacting the outer casing, causing electronic conduction and triggering an internal short circuit.

[0019] In some embodiments of the first aspect, the spacer extends along a second direction, and the two ends of the spacer along the second direction extend outward beyond the two ends of the anode sheet along the second direction, the second direction being perpendicular to the thickness direction of the anode sheet and parallel to the first wall.

[0020] In the technical solution of this application embodiment, the length of the separator in the second direction is greater than the length of the anode plate, and both ends extend beyond the anode plate, so that the anode plate is covered by the separator in multiple directions. This separates the bottom of the anode plate near the first wall from the first wall, and the anode plate from the outer casing, through the separator. In this way, the accumulation of anode particles, especially conductive materials, on the first wall can be reduced, thereby reducing the risk of conductive materials connecting the anode plate and the outer casing, causing the outer casing to become conductive and improving the reliability of the battery cell.

[0021] In some embodiments of the first aspect, in the second direction, the difference between the length L2 of the separator and the length L1 of the anode electrode satisfies: 5mm ≤ L2 - L1 ≤ 8mm.

[0022] In the technical solution of this application embodiment, setting the difference between the length of the separator and the length of the anode plate L2-L1 within this range can ensure that the separator has sufficient length to cover the anode plate, while avoiding the separator being too long and affecting the overall energy density.

[0023] In some embodiments of the first aspect, in the second direction, the length ΔL of the two ends of the separator extending outward beyond the two ends of the anode plate satisfies: 2.5mm≤ΔL≤4mm.

[0024] In the technical solution of this application embodiment, the two ends of the separator extend outward beyond the two ends of the anode sheet by a certain length, so that the projection of the anode sheet on the plane perpendicular to the thickness direction of the battery cell is approximately located at the center of the projection of the separator on the plane. This ensures that both ends of the anode sheet along the second direction have sufficient separators to catch particles that may fall off the anode sheet, further reducing the risk of electrical conduction between the anode sheet and the casing and improving the reliability of the battery cell.

[0025] In some embodiments of the first aspect, the spacer is integrally formed.

[0026] In the technical solution of this application embodiment, by integrally molding the separator, the structural strength and stability of the separator can be improved. Furthermore, continuous separators can simplify the processing of electrode assemblies and improve the processing efficiency of individual battery cells.

[0027] In some embodiments of the first aspect, the battery cell further includes a base plate located between the electrode assembly and the first wall, the base plate having a through groove along the thickness direction of the base plate.

[0028] In the technical solution of this application embodiment, the base plate can support the electrode assembly, reducing damage to the separator caused by electrode deformation and displacement, and further improving the isolation effect between the electrode and the casing. In addition, the base plate is provided with through grooves, allowing the electrolyte to more fully wet the electrode assembly, improving the charge and discharge performance of the battery cell. Furthermore, because the separator effectively covers the anode electrode, even with through grooves in the base plate, the separator in this application embodiment can reduce the risk of electrode powder shedding leading to casing corrosion.

[0029] In some embodiments of the first aspect, the base plate is provided with a plurality of through slots spaced apart along the second direction. In the second direction, the length of the through slot is W1 and the distance between two adjacent through slots is W2. Then W1 and W2 satisfy: 2mm≤W1≤30mm and 2mm≤W2≤20mm, respectively.

[0030] In the technical solution of this application embodiment, the length W1 of the through groove in the second direction is less than or equal to 30mm, which can avoid the reduction of the strength of the bottom support plate due to the excessive length of the through groove, provide sufficient support area for the electrode assembly, reduce the risk of bending, powder shedding, lithium plating and other problems caused by excessive local pressure on the electrode assembly, and improve the reliability of the battery cell. The length W1 of the through groove in the second direction is greater than or equal to 2mm, which allows the electrolyte to pass through the through groove better, thereby more fully wetting the electrode assembly. In addition, the through groove has this length, which has low process requirements and is simpler to process.

[0031] In addition, setting the spacing W2 between two adjacent through slots in the second direction to be less than or equal to 20 mm allows for the creation of more through slots, thereby promoting sufficient electrolyte wetting. Setting the spacing W2 between two adjacent through slots in the second direction to be greater than or equal to 2 mm can improve the support strength of the base plate, increase the support area of ​​the electrode assembly, reduce the risk of bending, powder shedding, and lithium plating caused by excessive local pressure on the electrode assembly, and improve the reliability of the battery cell.

[0032] In some embodiments of the first aspect, the base plate is provided with through grooves symmetrically along the thickness direction of the anode sheet, and the through grooves are located at the edge of the base plate along the thickness direction of the anode sheet.

[0033] In the technical solution of this application embodiment, by symmetrically arranging multiple spaced channels, the channels can be distributed at various positions on the bottom support plate, thereby promoting the electrolyte to be transported through multiple channels to the electrode assembly side, more fully wetting the electrode assembly, and improving the cycle performance and service life of the battery cell.

[0034] In some embodiments of the first aspect, in the thickness direction of the anode sheet, the length of the base plate is H1, and the length of the through groove is H2, wherein H1 and H2 satisfy: 8mm≤H1-2•H2≤98mm.

[0035] In the technical solution of this application embodiment, by setting the relationship between the length of the bottom support plate and the through groove in the thickness direction of the anode sheet to meet the requirements within this range, on the one hand, it can avoid the through groove being too long and affecting the support strength of the bottom support plate. The bottom support plate can provide sufficient support area for the electrode assembly, thereby reducing the risk of bending, powder shedding, lithium plating, etc. caused by excessive local pressure on the electrode assembly, and improving the reliability of the battery cell. On the other hand, a sufficiently long through groove can improve the wetting degree of the electrode liquid, thereby improving the cycle performance of the battery cell.

[0036] In some embodiments of the first aspect, the thickness of the base plate is greater than the radius of the chamfer between the second wall and the first wall, the second wall being a wall in the housing adjacent to the first wall.

[0037] In the technical solution of this application embodiment, the thickness of the base plate is greater than the radius of the chamfer between the second wall and the first wall, thereby raising the electrode assembly and making the anode or cathode electrode in the electrode assembly have a certain distance from the chamfer, reducing the risk of the electrode and the separator being damaged due to contact between the electrode and the chamfer, and improving the reliability of the battery cell.

[0038] In some embodiments of the first aspect, the battery cell further includes a pressure relief mechanism disposed on the first wall, and the base plate is also provided with a through hole along the thickness direction of the base plate. On a plane perpendicular to the thickness direction of the base plate, the projection of the pressure relief mechanism and the projection of the through hole at least partially coincide.

[0039] In the technical solution of this application embodiment, on the one hand, the pressure relief mechanism is disposed on the first wall, that is, on the bottom wall of the battery cell. Thus, when the pressure relief mechanism is actuated, the effluent inside the battery cell can be discharged towards the bottom, thereby preventing high-temperature substances from directly impacting the sensitive components above the battery cell and reducing the risk of a chain reaction leading to the failure of multiple battery cells. On the other hand, the pressure relief mechanism at least partially overlaps with the through-hole on the bottom plate. Especially in the event of thermal runaway in the battery cell, gases and other substances generated inside the electrode assembly can be discharged through the through-hole from the pressure relief mechanism, reducing gas accumulation inside and improving the reliability of the battery cell. Furthermore, since the separator can block the electrode from the first wall, it can reduce the accumulation of easily detachable substances on the electrode in the pressure relief mechanism, reducing the risk of corrosion of the pressure relief mechanism, especially its weak areas, and improving the reliability of the battery cell.

[0040] In some embodiments of the first aspect, the battery cell further includes an insulating element that at least covers the end of the electrode assembly near the first wall.

[0041] In the technical solution of this application embodiment, the insulating member covers the end of the electrode assembly, thereby isolating all the anode and cathode plates in the electrode assembly from the first wall by the insulating member, thereby further reducing the risk that the conductive material on the electrode plate will conduct electricity between the electrode plate and the outer shell.

[0042] In some embodiments of the first aspect, the housing includes a shell and end caps. The shell has two openings disposed opposite each other along a second direction. The shell includes the first wall. The end caps include a first end cap and a second end cap, which respectively cover the two openings of the shell. The first end cap and the second end cap are the two walls of the shell with the smallest area. The second direction is perpendicular to the thickness direction of the anode electrode and parallel to the first wall.

[0043] In the technical solution of this application embodiment, the shell has two openings, and the two openings are arranged opposite to each other along the second direction. The end caps, including the first end cap and the second end cap, are respectively covered by the two openings. The first end cap and the second end cap are the walls with the smallest area in the shell. That is, the anode electrode and the cathode electrode in the electrode assembly are alternately stacked along the thickness direction of the battery cell. At the same time, the anode electrode and the cathode electrode can extend along the length direction of the battery cell, and the separator can also extend along the length direction of the battery cell, thereby covering the longer part of the electrode, further reducing the risk of the conductive material overlapping the electrode with the shell, and improving the reliability of the battery cell.

[0044] In some embodiments of the first aspect, the battery cell further includes a first electrode terminal and a second electrode terminal, the first electrode terminal being disposed on the first end cap and the second electrode terminal being disposed on the second end cap; the electrode assembly has a first tab and a second tab, the first tab and the second tab being respectively located at both ends of the electrode assembly along the second direction, the first tab connecting the anode plate and the first electrode terminal, and the second tab connecting the cathode plate and the second electrode terminal.

[0045] In the technical solution of this application embodiment, the first electrode tab and the second electrode tab are respectively disposed at both ends of the electrode assembly along the second direction. Since the isolation member is disposed at the large surface of the electrode sheet and at both ends of the electrode assembly in the direction perpendicular to the first wall, that is, the first electrode tab and the second electrode tab are led out from the two ends of the electrode sheet where the isolation member is not disposed, the risk of the electrode tab puncturing the isolation member can be reduced and the isolation effect of the isolation member can be improved.

[0046] In a second aspect, a battery device is provided, including a housing with a hollow interior; and a plurality of battery cells as described in the first aspect or any embodiment thereof, wherein the plurality of battery cells are housed within the housing.

[0047] In some embodiments of the second aspect, the housing includes an upper housing and a lower housing, the lower housing having an opening, the upper housing covering the opening, and the lower housing supporting a plurality of battery cells; the electrode assembly of the battery cell includes an anode electrode, a cathode electrode, and a separator, the separator covering the end of the anode electrode near the lower housing.

[0048] In the technical solution of this application embodiment, regardless of how the battery cell is placed in the box, the separator always covers the area of ​​the anode plate near the end of the lower box along the direction of gravity, thereby reducing the risk of easily detachable conductive material on the electrode plate accumulating on the outer shell of the battery cell and causing corrosion of the outer shell, and improving the reliability of the entire battery device.

[0049] Thirdly, an electrical device is provided, including a battery cell as described in the first aspect or any embodiment of the first aspect, or a battery device as described in the second aspect or any embodiment of the second aspect, the battery cell or the battery device being used to provide electrical energy. Attached Figure Description

[0050] Figure 1 A schematic diagram of the structure of a vehicle according to an embodiment of this application is shown;

[0051] Figure 2 A partial structural schematic diagram of a battery device according to an embodiment of this application is shown;

[0052] Figure 3A schematic diagram of the structure of a battery cell according to an embodiment of this application is shown;

[0053] Figure 4 A schematic diagram of the structure of an electrode assembly according to an embodiment of this application is shown;

[0054] Figure 5 A schematic diagram of the structure of an electrode assembly according to another embodiment of this application is shown;

[0055] Figure 6 A schematic diagram of the structure of an electrode assembly according to another embodiment of this application is shown;

[0056] Figure 7 A schematic diagram of the structure of an electrode assembly according to another embodiment of this application is shown;

[0057] Figure 8 A schematic diagram of the structure of an electrode assembly according to another embodiment of this application is shown;

[0058] Figure 9 A cross-sectional view of an electrode assembly according to an embodiment of this application is shown along section line A-A'.

[0059] Figure 10 A side view of a battery cell according to an embodiment of this application is shown;

[0060] Figure 11 A cross-sectional view of a battery cell according to an embodiment of this application is shown along section line B-B'.

[0061] Figure 12 A partial schematic diagram of part C of a battery cell according to an embodiment of this application is shown;

[0062] Figure 13 A cross-sectional view of a battery cell along section line D-D' is shown, representing another embodiment of this application.

[0063] The labels for each figure are as follows:

[0064] 1-Vehicle; 10-Battery unit; 11-Box; 111-Upper box; 112-Lower box; 20-Battery cell; 21-Shell; 201-First wall; 202-Second wall; 211-Shell; 212-End cap; 212a-First end cap; 212b-Second end cap; 22-Electrode assembly; 221a-Anode electrode; 221b-Cathode electrode; 222-Separator; 2221-Main body section; 2222-First bending section; 2223-Second bending section; 2224-Extension section; 2225-Third bending section; 23a-First electrode terminal; 23b-Second electrode terminal; 24-Bottom plate; 241-Through groove; 242-Through hole; 25-Insulator; 30-Controller; 40-Motor. Detailed Implementation

[0065] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0066] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0067] The term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / " in this text generally indicates that the preceding and following related objects have an "or" relationship.

[0068] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0069] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0070] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0071] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0072] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0073] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator positioned between the positive and negative electrodes. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0074] 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 disposed on at least one surface of the positive electrode current collector.

[0075] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0076] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0077] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0078] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0079] As an example, negative electrode active materials can be filled or / and deposited within the negative electrode current collector.

[0080] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0081] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0082] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0083] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0084] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0085] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0086] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0087] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0088] In some implementations, the electrode assembly is a stacked structure.

[0089] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0090] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0091] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0092] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0093] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0094] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0095] In some embodiments, the electrode assembly has tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0096] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0097] In some embodiments, the housing includes an end cap and a housing, the housing having an opening, and the end cap covering the opening. The housing may have one or more openings. The end cap may also be provided one or more.

[0098] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab. The electrode terminal can be directly connected to the tab, or it can be indirectly connected to the tab through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0099] In some embodiments, a pressure relief mechanism is provided on the casing. The pressure relief mechanism is used to release the internal gas of the battery cell.

[0100] As an example, the internal pressure or temperature of a battery cell is actuated to release the internal pressure or temperature when it reaches a predetermined threshold. When the internal pressure or temperature of the battery cell reaches the predetermined threshold, the pressure relief mechanism is activated or a weak structure in the pressure relief mechanism is broken, thereby creating an opening or channel for the internal pressure or temperature to be released. The threshold design varies depending on the design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell.

[0101] As an example, the pressure relief mechanism can be integrally molded with the housing.

[0102] As an example, the pressure relief mechanism can also be separately installed and connected to the housing.

[0103] The term "actuation" as used in this application refers to the activation or actuation of the pressure relief mechanism to a certain state, thereby releasing the internal pressure and temperature of the battery cell. The actions of the pressure relief mechanism may include, but are not limited to: movement of components within the mechanism to form an exhaust channel, rupture, breakage, tearing, or opening of at least a portion of the mechanism, etc. When the pressure relief mechanism is activated, the high-temperature, high-pressure substances inside the battery cell are discharged as waste from the activated portion. This method allows for pressure and temperature relief of the battery cell under controllable pressure or temperature, thereby preventing potentially more serious accidents.

[0104] In some embodiments, when the housing is a non-sealed structure, the pressure relief mechanism can be configured as a through hole for venting gas inside the battery cell.

[0105] The emissions from battery cells mentioned in this application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0106] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0107] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0108] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0109] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0110] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0111] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0112] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0113] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0114] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0115] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use individual battery cells, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0116] The development of battery technology must consider multiple design factors simultaneously, such as energy density, cycle life, discharge capacity, and charge / discharge rate. As one of the core components within a battery cell, the design and manufacturing process of the electrode assembly directly impacts the overall battery performance. In practical applications, easily detachable materials often fall from the electrodes, contaminating the internal structure. In particular, the detachment of conductive materials can cause conductivity issues between the electrode and its underlying casing, leading to internal short circuits within the battery cell and even accelerating corrosion, severely affecting its performance.

[0117] Therefore, embodiments of this application provide a battery cell, a battery device, and an electrical appliance that can solve the above-mentioned problems. The battery cell of this application includes a casing and an electrode assembly. The casing has a receiving space and a first wall, which is located at the bottom of the receiving space in the direction of gravity. The electrode assembly is housed in the receiving space and includes multiple anode plates, multiple cathode plates, and a separator. The anode plates and cathode plates are sequentially and alternately stacked. The end of the anode plate near the first wall extends beyond the end of the cathode plate near the first wall. The separator includes a main body segment and a first bent segment. The main body segment is disposed between adjacent anode and cathode plates, and the first bent segment is connected to two adjacent main body segments located on both sides of the anode plate. The first bent segment is located on the side of the main body segment near the first wall. The diameter φ1 of the anode particles on the anode plate is larger than the pore diameter φ2 of the separator.

[0118] This design allows the separator to completely cover the anode plate from the bottom. Since the particle size of the anode particles on the anode plate is larger than the pore diameter of the separator, even if anode particles detach, they cannot pass through the separator, thus preventing them from falling onto the casing. This effectively blocks the anode particles, especially the conductive material within them, from directly contacting the casing, reducing the risk of conductivity between the anode plate and the casing, lowering the risk of the casing becoming charged and corroding, and improving the reliability of the battery cell. Furthermore, because the bottom of the anode plate extends beyond the bottom of the cathode plate, the bottom of the cathode plate is also covered, further reducing the risk of conductivity between the cathode plate and the casing, lowering the risk of the casing becoming charged and corroding, and further improving the reliability of the battery cell.

[0119] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery devices.

[0120] Electrical equipment can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical equipment.

[0121] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0122] like Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of a vehicle 1 according to one embodiment of this application. Vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A motor 40, a controller 30, and a battery device 10 can be installed inside vehicle 1. The controller 30 controls the battery device 10 to supply power to the motor 40. For example, the battery device 10 can be installed at the bottom, front, or rear of vehicle 1. The battery device 10 can be used to power vehicle 1. For example, the battery device 10 can serve as the operating power source for vehicle 1, for example, to meet the electrical system needs of vehicle 1, such as for starting, navigation, and operation. In another embodiment of this application, the battery device 10 can not only serve as the operating power source for vehicle 1, but also as the driving power source for vehicle 1, replacing or partially replacing gasoline or natural gas to provide driving power for vehicle 1.

[0123] Figure 2 A partial structural schematic diagram of the battery device 10 according to an embodiment of this application is shown. Figure 2 As shown, the battery device 10 of this application embodiment may include a plurality of battery cells 20 to meet different power usage requirements. The shape of the battery cell 20 in this application embodiment can be set according to actual application. For example, the battery cell 20 can be as follows: Figure 2 The cuboid shown can also be different. Figure 2 The embodiments shown are cylindrical or other shapes, but are not limited to these.

[0124] It should be understood that, such as Figure 2As shown, the battery device 10 of this embodiment may further include a housing 11, which can be used to accommodate multiple battery cells 20. The housing 11 of this embodiment has a hollow interior, and the multiple battery cells 20 are accommodated within the housing 11. The housing 11 may include two parts, referred to herein as an upper housing 111 and a lower housing 112, which are fastened together. The shapes of the upper housing 111 and the lower housing 112 can be determined according to the shape of the components housed inside, for example, according to the shape of the combination of the multiple battery cells 20 housed inside. At least one of the upper housing 111 and the lower housing 112 has an opening. For example, as... Figure 2 As shown, the upper housing 111 and the lower housing 112 can both be hollow cuboids with one open side each. The openings of the upper housing 111 and the lower housing 112 are opposite to each other, and the upper housing 111 and the lower housing 112 are interlocked to form a housing 11 with a closed chamber. This chamber can accommodate multiple battery cells 20. The multiple battery cells 20 are connected in parallel, series, or mixed and placed inside the housing 11 formed by the interlocking of the upper housing 111 and the lower housing 112.

[0125] For example, unlike Figure 2 As shown, either the upper housing 111 or the lower housing 112 can be a hollow cuboid with an opening, while the other is plate-shaped to cover the opening. Taking the lower housing 112 as a hollow cuboid with one opening and the upper housing 111 as a plate as an example, the upper housing 111 covers the opening of the lower housing 112 to form a housing 11 with a closed chamber, which can be used to accommodate multiple battery cells 20.

[0126] Figure 3 A schematic diagram of the structure of a battery cell 20 according to an embodiment of this application is shown, for example, Figure 3 The battery cell 20 shown can be Figure 2 Any one of the battery cells 20 in the battery device 10 shown; Figure 4 This illustration shows a schematic diagram of the structure of an electrode assembly 22 according to one embodiment of this application, for example, Figure 4 It can be Figure 3 A schematic diagram of an electrode assembly 22 in the battery cell 20 shown; Figure 5 This illustration shows a schematic diagram of the structure of an electrode assembly 22 according to one embodiment of this application, for example, Figure 5 It can be Figure 3 Another structural schematic diagram of the electrode assembly 22 in the battery cell 20 shown.

[0127] like Figures 3 to 5As shown, the battery cell 20 includes a housing 21 and an electrode assembly 22. Specifically, the housing 21 has a receiving space and a first wall 201, which is located at the bottom of the receiving space in the direction of gravity. The electrode assembly 22 is housed in the receiving space and includes multiple anode plates 221a, multiple cathode plates 221b, and a separator 222. The anode plates 221a and cathode plates 221b are arranged in an alternating layer, with one end of the anode plate 221a near the first wall 201 extending beyond the end of the cathode plate 221b near the first wall 201. At one end, the separator 222 includes a main body segment 2221 and a first bent segment 2222; wherein, the main body segment 2221 is disposed between adjacent anode plates 221a and cathode plates 221b, and the first bent segment 2222 is connected to two adjacent main body segments 2221 located on both sides of the anode plate 221a, and the first bent segment 2222 is located on the side of the main body segment 2221 near the first wall 201; wherein, the diameter φ1 of the anode particles on the anode plate 221a is greater than the pore diameter φ2 of the separator 222.

[0128] The battery cell 20 in this embodiment includes a casing 21. The casing 21 can be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc.

[0129] It should be understood that the battery cell 20 in this application embodiment can be a cylindrical battery cell, a prismatic battery cell, a pouch battery, or a battery cell of other shapes. Among them, the prismatic battery cell can include a prismatic battery cell, a blade-shaped battery cell, or other multi-prismatic battery cells, such as a hexagonal prismatic battery cell or an octagonal prismatic battery cell, and this application embodiment is not limited to these.

[0130] In this embodiment, the shape of the battery cell 20 is the same as the shape of the outer casing 21. That is, the outer casing 21 of the battery cell 20 can be any polyhedron, for example, a cuboid or a cylinder. The external shape of the battery cell 20 can be the same as or different from the shape of its internal electrode assembly 22. For example, if the electrode assembly 22 is a cylindrical structure, the outer casing 21 of the battery cell 20 can also be a cylindrical structure, or it can be a cuboid structure; if the electrode assembly 22 is a cuboid structure, the outer casing 21 can usually also be a cuboid structure, but this embodiment is not limited to this. For example, as... Figure 3 As shown in the embodiments of this application, the description mainly takes the hollow cuboid structure of the outer shell 21 as an example.

[0131] In some embodiments, the housing 21 can be a sealed structure or a non-sealed structure. As an example, when the housing 21 is a non-sealed structure, it serves to protect the electrode assembly 22, and a sealing bag is included between the housing 21 and the electrode assembly 22. The sealing bag is used to encapsulate the electrode assembly 22 and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film. When the housing 21 is a sealed structure, it is used to encapsulate the electrode assembly 22 and the electrolyte, among other components.

[0132] The outer casing 21 of this embodiment has a first wall 201, which is a wall in the outer casing 21 perpendicular to the direction of gravity. It should be understood that the first wall 201 is located at the bottom of the accommodating space, meaning that the first wall 201 is a wall in the outer casing 21 perpendicular to the direction of gravity and located at the bottom of the accommodating space. For example, when the battery cell 20 is normally placed, the first wall 201 can be the bottom wall of the battery cell 20.

[0133] Additionally, for ease of description, the rectangular battery cell 20, such as Figure 3 As shown, this application defines three reference directions in its embodiments. The length direction of the battery cell 20 is direction X, the thickness direction of the battery cell 20 is direction Y, and the height direction of the battery cell 20 is direction Z. The length direction X, thickness direction Y, and height direction Z of the battery cell 20 are perpendicular to each other, and the dimension of the thickness direction Y of the battery cell 20 is smaller than the dimension of the length direction X. It should be understood that the thickness direction of the battery cell 20 can also be the thickness direction of the electrode assembly or the thickness direction of the electrode sheet. In the following figures, the first direction being the height direction of the battery cell 20 (i.e., direction Z) and the second direction being the length direction of the battery cell 20 (i.e., direction X) will be used as an example for illustration.

[0134] The battery cell 20 in this embodiment further includes an electrode assembly 22. The electrode assembly 22 is a component in the battery cell 20 where an electrochemical reaction occurs. Depending on actual usage requirements, the electrode assembly 22 inside the casing 21 can be one or more. The electrode assembly 22 can be a cylinder, a cuboid, etc. If the electrode assembly 22 is a cylindrical structure, the casing 21 can also be a cylindrical structure; if the electrode assembly 22 is a cuboid structure, the casing 21 can also be a cuboid structure.

[0135] like Figure 4As shown, the electrode assembly 22 in this embodiment may include a plurality of anode plates 221a and a plurality of cathode plates 221b. The electrode assembly 22 may be formed by sequentially and alternately stacking the anode plates 221a and cathode plates 221b. For example, the electrode assembly 22 may include a plurality of anode plates 221a and a plurality of cathode plates 221b. Along the thickness direction of the electrode assembly 22, the plurality of positive electrode plates 223 and the plurality of negative electrode plates 224 are alternately stacked to form a stacked electrode assembly 22. The thickness direction of the electrode assembly 22 may be as follows: Figure 3 The thickness direction Y of the battery cell 20 shown. For example, the electrode assembly 22 may include multiple anode plates 221a and cathode plates 221b, which include multiple bent segments and multiple stacked segments that are interconnected and alternately arranged. After the bent segments are bent, the multiple anode plates 221a and the multiple stacked segments of the cathode plates 221b are alternately stacked to form a stacked electrode assembly 22.

[0136] The length of the anode electrode 221a can be greater than or equal to the length of the cathode electrode 221b. It should be understood that the length of the anode electrode 221a or the cathode electrode 221b can refer to the dimension in the height direction or the length direction of the electrode assembly 22.

[0137] In the height or length direction of the electrode assembly 22, the size of the anode electrode 221a exceeds the size of the cathode electrode 221b. For example, it can mean that in the height direction of the electrode assembly 22, the size of the anode electrode 221a exceeds the size of the cathode electrode 221b, while in the length direction of the electrode assembly 22, the size of the cathode electrode 221b may slightly exceed the size of the anode electrode 221a. Alternatively, it can mean that in both the height and length directions of the electrode assembly 22, the size of the anode electrode 221a exceeds the size of the cathode electrode 221b, that is, the orthographic projection area of ​​the cathode electrode 221b along the thickness direction is located within the orthographic projection area of ​​the anode electrode 221a along the thickness direction.

[0138] It should be understood that, regardless of whether it is in the length direction or the height direction of the electrode assembly 22, "exceeding" can refer to exceeding one or both ends along that direction, and the embodiments of this application are not limited thereto.

[0139] For example, in some embodiments, the end of the anode electrode 221a near the first wall 201 extends beyond the end of the cathode electrode 221b near the first wall 201. That is, the anode electrode 221a is closer to the first wall 201 than the cathode electrode 221b. Thus, during the packaging of the electrode assembly 22 into the casing, two adjacent anode electrodes 221a can cover the bottom of the cathode electrode 221b near the first wall 201. Therefore, only the bottom of the anode electrode 221a needs to be covered, which reduces the risk of particles falling off any electrode and causing electrical conduction with the casing 21, thereby improving the reliability of the battery cell 20.

[0140] In some embodiments, the length of the anode electrode 221a is greater than the length of the cathode electrode 221b. This can reduce the risk of lithium ions preferentially precipitating at the edge of the cathode electrode 221b, leading to local dendrite growth or gas generation. At the same time, it can improve the ability of the anode electrode 221a to receive lithium ions and reduce the risk of local overcharging caused by the cathode electrode 221b not being completely covered by the anode electrode 221a.

[0141] The electrode assembly 22 in this embodiment may further include an isolator 222. The isolator 222 may include a main body segment 2221. The main body segment 2221 is located between adjacent anode plates 221a and cathode plates 221b to isolate the anode plates 221a and 221b, prevent short circuits between the cathode and anode, and the main body segment 2221 also enables active ions to be inserted and extracted back and forth between the anode and cathode, thereby playing the role of transporting ions between the cathode and anode.

[0142] It should be understood that the main body segment 2221 may refer to the portion of the separator 222 located between adjacent anode plates 221a and cathode plates 221b, and the plane on which the main body segment 2221 is located is parallel to the plane on which the anode plate 221a or the cathode plate 221b is located.

[0143] The main body segment 2221 may include one or more. For example, multiple main body segments 2221 may be placed between multiple adjacent anode plates 221a and cathode plates 221b, so that a main body segment 2221 is provided between any adjacent anode plates 221a and cathode plates 221b, thereby effectively isolating the anode plates 221a and cathode plates 221b and reducing the risk of short circuit between them.

[0144] The separator 222 may further include a first bent section 2222, which connects two adjacent main body sections 2221 on both sides of the anode electrode 221a. It should be understood that "both sides of the anode electrode 221a" can refer to both sides along the thickness direction of the anode electrode 221a. When both sides of the anode electrode 221a along its thickness direction are provided with main body sections 2221, these two main body sections 2221 are adjacent, and the first bent section 2222 connects these two adjacent main body sections 2221.

[0145] The first bending segment 2222 is located on the side of the main body segment 2221 near the first wall 201, that is, the first bending segment 2222 is located at the bottom of the main body segment 2221. The first bending segment 2222 connects the bottom of the anode plate 221a to two adjacent main body segments 2221, so that the main body segment 2221, the first bending segment 2222 and the main body segment 2221 connected in sequence cover the bottom of the anode plate 221a, and isolate the bottom of the anode plate 221a from the outer shell 21. This can prevent the conductive material that falls off the anode plate 221a from accumulating under the action of gravity and contacting the outer shell 21, thereby reducing the risk of corrosion of the outer shell 21 due to the conduction between the anode plate 221a and the outer shell 21, and improving the reliability of the battery cell 20.

[0146] It should be understood that the first bending segment 2222 may refer to the part of the separator 222 that connects the two adjacent main body segments 2221 located on both sides of the anode electrode 221a, and the first bending segment 2222 is located between the anode electrode 221a or the cathode electrode 221b and the first wall 201.

[0147] The number of first bending segments 2222 can be one or more. For example, multiple first bending segments 2222 can be connected to two adjacent main body segments 2221 located on both sides of the corresponding anode electrode 221a. The number of multiple first bending segments 2222 can be equal to or less than the number of multiple anode electrodes 221a. For example, as... Figure 4 As shown, when the multiple anode plates 221a and multiple cathode plates 221b in the electrode assembly 22 are arranged in an alternating stack with the cathode plates 221b as the beginning and end, each anode plate 221a can have a main body segment 2221 on both sides. Then, multiple first bending segments 2222 correspond one-to-one with multiple anode plates 221a, and each first bending segment 2222 connects to the main body segment 2221 on both sides of its corresponding anode plate 221a.

[0148] For example, such as Figure 5As shown, when the multiple anode plates 221a and multiple cathode plates 221b in the electrode assembly 22 are staggered and stacked starting with and / or ending with the anode plate 221a, a main body segment 2221 can be provided on the side of the outermost anode plate 221a in the thickness direction near the inner side. Then, the number of multiple first bending segments 2222 can be less than the number of multiple anode plates 221a. The multiple first bending segments 2222 correspond one-to-one with the multiple anode plates 221a except for the outermost ones. Each first bending segment 2222 connects to the main body segments on both sides of the anode plate 221a it corresponds to.

[0149] In addition, the connection between the first bending segment 2222 and the two adjacent main segments 2221 can be by snap-fitting, bonding, sewing, etc., and the specific connection method is not limited.

[0150] In this embodiment, the diameter φ1 of the anode particles on the anode electrode 221a is greater than the pore diameter φ2 of the separator 222.

[0151] It should be understood that anode particles can refer to various substances used in the preparation of anode electrode 221a, including active material particles, conductive material particles, binder particles, and other functional additive particles.

[0152] It should be understood that the separator 222 is a porous structure that allows ions to pass through during battery charging and discharging. That is, the pore diameter of the separator 222 can be larger than the particle size of the ions, thereby ensuring the normal operation of battery charging and discharging. By setting the pore diameter of the separator 222 to be smaller than the diameter of the anode particles, the risk of anode particles detached from the anode electrode 221a passing through the separator 222 and contacting the outer casing 21 can be reduced, thereby reducing the risk of corrosion of the outer casing 21 due to current conduction between the anode electrode 221a and the outer casing 21.

[0153] The pores at any location in the separator 222 can satisfy the condition that their diameter is smaller than the diameter of the anode particles on the anode electrode 221a, or this condition can be satisfied by pores at certain locations. For example, the pore diameters of both the main body section 2221 and the first bending section 2222 in the separator 222 can be smaller than the diameter of the anode particles. Alternatively, the pore diameter of the first bending section 2222 in the separator 222 can be smaller than the diameter of the anode particles.

[0154] In some embodiments, the pore diameter of the separator 222 may be smaller than the diameter of the cathode particles on the cathode electrode 221b, thereby further reducing the risk of detached particles on any electrode passing through the separator 222 and making contact with the casing 21, and improving the reliability of the battery cell 20.

[0155] In this embodiment, the separator 222 can cover the anode electrode 221a from its bottom, and the particle size of the anode particles on the anode electrode 221a is larger than the pore diameter of the separator 222. Even if the anode particles fall off, they cannot pass through the separator 222, thereby preventing them from falling onto the outer casing 21. This effectively prevents the anode particles on the anode electrode 221a, especially the conductive material therein, from directly contacting the outer casing 21, thus reducing the risk of the anode electrode 221a becoming conductive with the outer casing 21, reducing the risk of the outer casing 21 becoming charged and corroded, and improving the reliability of the battery cell 20. In addition, since the bottom of the anode electrode 221a extends beyond the bottom of the cathode electrode 221b, the bottom of the cathode electrode 221b is also covered, thereby reducing the risk of the cathode electrode 221b becoming conductive with the outer casing 21, reducing the risk of the outer casing 21 becoming charged and corroded, and further improving the reliability of the battery cell 20.

[0156] In some embodiments, the particle size φ1 of the anode particles on the anode electrode 221a satisfies: 8μm≤φ1≤37μm, and the pore diameter φ2 of the separator 222 satisfies: 50nm≤φ2≤300nm.

[0157] It should be understood that the anode electrode 221a has various types and sizes of anode particles, and the particle size of the anode particles in this embodiment should all meet this range. For example, the anode particles may include active material particles, conductive material particles, binder particles, and other functional additive particles. In addition, particle size can refer to the minimum particle size, the maximum particle size, or the average particle size.

[0158] Typically, this particle size refers to the volume average particle size of the anode particles, which can be determined using instruments and methods known in the art. As an example, a battery cell is disassembled to obtain the anode electrode. The anode film layer is scraped off to obtain anode film powder. The anode film powder is then mixed with water, filtered, and dried to obtain individual anode particles. Subsequently, the particle size is conveniently determined using a laser particle size analyzer, referring to GB / T19077-2016, Particle Size Distribution by Laser Diffraction. For example, a Mastersizer 3000 laser particle size analyzer from Malvern Instruments Ltd., UK, can be used.

[0159] The pore diameter of the separator 222 can refer to the average pore diameter or the minimum pore diameter on the separator 222, and its measurement can be performed using instruments and methods known in the art. As an example, the battery cell is disassembled to obtain the separator, and two circular areas with a diameter of 5 mm are arbitrarily selected on the separator; the minimum pore diameter d1 of any one of these areas is directly observed under a scanning electron microscope (SEM). The minimum pore diameter d2 of the other areas is observed using the same method, and the minimum value between d1 and d2 is taken as the pore diameter of the separator.

[0160] In this embodiment, regarding the diameter φ1 of the anode particles, on the one hand, the diameter φ1 of the anode particles is set to be less than or equal to 37 μm. During the charging and discharging process, the small-diameter particles can quickly embed and / or de-embed, improving the discharge rate of the battery, while reducing the stress during the battery expansion process, and improving the cycle life of the battery cell 20. In addition, the small gap between the small-diameter particles can improve the energy density. On the other hand, setting the diameter φ1 of the anode particles to be greater than or equal to 8 μm can avoid the particle size from causing a sharp increase in specific surface area, reducing the degree of side reaction with the electrolyte, thereby improving the cycle stability of the battery cell 20. Regarding the pore diameter φ2 of the separator 222, on the one hand, setting the pore diameter φ2 of the separator 222 to be less than or equal to 300nm can prevent various particles on the electrode from passing through the pores of the separator 222, reducing the risk of current conduction between the positive and negative electrodes or between the electrode and other components such as the casing. In addition, it can reduce the risk of short circuits caused by the penetration of metal dendrites such as lithium dendrites, thereby improving the overall reliability of the battery cell 20. On the other hand, setting the pore diameter φ2 of the separator 222 to be greater than or equal to 50nm can ensure that the separator 222 has a sufficient size for ions to pass through while avoiding blockage due to excessively small pores, thereby improving the overall cycle life of the battery cell 20.

[0161] In some embodiments, the diameter φ1 of the anode particles can be any of the following values ​​or between the following values: 8μm, 16μm, 22μm, 28μm, 34μm, 35μm, 36μm, 37μm.

[0162] In some embodiments, the pore diameter φ2 of the separator 222 can be any of the following values ​​or between any of the following values: 50nm, 70nm, 90nm, 110nm, 130nm, 150nm, 170nm, 190nm, 200nm, 230nm, 250nm, 270nm, 280nm, 300nm.

[0163] In some embodiments, the electrodes may have an adhesive. The anode electrode 221a and / or the cathode electrode 221b may have an adhesive, thereby enabling various particulate materials on the electrodes to be firmly bonded to the electrodes, reducing the risk of them falling off.

[0164] For example, in some embodiments, the ratio R of the binder content to the anode particle content on the anode electrode 221a can satisfy: 0.5% ≤ R ≤ 1.2%.

[0165] It should be understood that the adhesive on the anode electrode 221a can also be considered part of the anode particles, meaning that the anode particles include the adhesive. The adhesive is mainly used to bond other active and conductive materials within the anode particles.

[0166] In this embodiment, the binder content is set within this range. On the one hand, it can avoid insufficient particle bonding strength on the anode electrode 221a, reducing phenomena such as powder shedding and separation during coating and rolling. On the other hand, it can avoid excessive binder content from crowding out the volume of active material, increasing the energy density of the battery cell 20. It can also avoid excessive binder from clogging the pores of the electrode, improving the effectiveness of electrolyte wetting and ion transport, and improving the overall charge and discharge performance of the battery cell 20.

[0167] In some embodiments, the ratio R of the binder content on the anode electrode 221a to the anode particle content can be any of the following values ​​or between any of the following values: 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%.

[0168] The separator 222 can completely cover the anode electrode 221a and / or the cathode electrode 221b.

[0169] It is understood that the dimension of the separator 222 in the length direction X of the battery cell 20 can be greater than or equal to the dimension of the electrode in the length direction X. The dimension of the separator 222 in the height direction Z of the battery cell 20 can also be greater than or equal to the dimension of the electrode in the height direction Z.

[0170] For example, the dimensions of the first bent segment 2222 and / or the main body segment 2221 in the separator 222 in the length direction X of the battery cell 20 can be greater than or equal to the dimensions of the anode plate 221a in the length direction X, so that the first bent segment 2222 can completely cover the bottom of the corresponding anode plate 221a.

[0171] For example, the size of the main body segment 2221 in the separator 222 in the height direction Z of the battery cell 20 can be greater than or equal to the size of the electrode in the height direction X, so that the main body segment 2221 can completely cover the large surface of the electrode perpendicular to the thickness direction, thereby better isolating the anode electrode 221a and the cathode electrode 221b.

[0172] In some embodiments, continue to refer to Figure 4 and Figure 5 The main body segment 2221 extends along the first direction and away from the first bending segment 2222. The two ends of the main body segment 2221 extend outward beyond the two ends of the anode plate 221a in the first direction. The first direction is perpendicular to the first wall 201.

[0173] It should be understood that the first direction can be as follows: Figure 4 and Figure 5The Z direction is shown. In this embodiment, "outward" can refer to the main body segment 2221 extending outward along the first direction towards the outside of the battery cell 20, or it can refer to the main body segment 2221 extending outward along the first direction away from the center of symmetry of the main body segment 2221. Figure 5 For example, the two ends of the main body segment 2221 extend outward beyond the two ends of the anode plate 221a along the first direction. That is, the upper end of the main body segment 2221 along the Z direction extends upward beyond the upper end of the anode plate 221a along the Z direction, and the lower end of the main body segment 2221 along the Z direction extends downward beyond the lower end of the anode plate 221a along the Z direction. This makes the length of the main body segment 2221 in the Z direction greater than the length of the anode plate 221a in the Z direction, and the projection of the main body segment 2221 on the plane perpendicular to the Y direction completely covers the projection of the anode plate 221a on the plane perpendicular to the Y direction.

[0174] In this embodiment, the length of the main body segment 2221 in the first direction is greater than the length of the anode electrode 221a, and both ends extend beyond the anode electrode 221a, so that the orthographic projection of the anode electrode 221a along its thickness direction is located within the orthographic projection of the main body segment 2221 along its thickness direction. The sides of adjacent anode electrodes 221a and cathode electrodes 221b that are close to each other in the thickness direction are completely separated by the main body segment 2221, thereby reducing the risk of internal short circuit caused by direct contact between the anode and cathode electrodes leading to electronic conduction.

[0175] It should be understood that, since the length of the anode electrode 221a is generally greater than the length of the cathode electrode 221b, that is, along the first direction, the two ends of the anode electrode 221a extend beyond the two ends of the cathode electrode 221b. For example... Figure 6 As shown, Figure 6 As shown Figure 4 The diagram shows a possible structural configuration of the electrode assembly 22 in an actual product. Figure 4 As shown, due to the extreme thinness of the electrode and the separator, during the assembly of the electrode assembly 22, the portions of the main body segments 2221 on both sides of the anode electrode 221a that extend beyond the anode electrode 221a along the first direction, and the corresponding first bent segments 2222 connected to the main body segments 2221, are offset to a certain extent in the stacking direction of the electrode. This causes some adjacent first bent segments 2222 to overlap, and the portions of adjacent main body segments 2221 that extend beyond the anode electrode 221a are offset to below the cathode electrode 221b adjacent to the anode electrode 221a, forming as shown in the figure. Figure 6 The diagram shows the structure of the electrode assembly 22. This allows the bottom of the cathode electrode 221b to be isolated from the outer casing 21, preventing trace amounts of conductive material that detaches from the cathode electrode 221b from contacting the outer casing. It also reduces the risk of the outer casing 21 becoming charged and corroded due to the conductivity between the anode electrode 221a and the cathode electrode 221b and the outer casing 21, further improving the reliability of the battery cell 20.

[0176] In some embodiments, such as Figure 7 As shown, Figure 7 It shows Figure 3 Another structural schematic diagram of the electrode assembly 22 in the battery cell 20 is shown. The separator 222 also includes a second bent section 2223; the second bent section 2223 is connected to two adjacent main body sections 2221 located on both sides of the cathode electrode 221b, and the second bent section 2223 is located on the side of the main body section 2221 away from the first wall 201.

[0177] It should be understood that the two sides of the cathode electrode 221b can refer to the two sides of the cathode electrode 221b in the thickness direction. When the cathode electrode 221b is provided with main body segments 2221 on both sides along its thickness direction, the two main body segments 2221 are adjacent, and the second bending segment 2223 connects the two adjacent main body segments 2221.

[0178] The second bending segment 2223 may refer to the part of the separator 222 that connects the two adjacent main body segments 2221 located on both sides of the cathode electrode 221b, and the second bending segment 2223 is located on the side of the anode electrode 221a or the cathode electrode 221b away from the first wall 201.

[0179] The number of second bending segments 2223 can be one or more. For example, multiple second bending segments 2223 can be connected to two adjacent main body segments 2221 located on both sides of the corresponding cathode electrode 221b. The number of multiple second bending segments 2223 can be equal to or less than the number of multiple cathode electrodes 221b. For example, Figure 7 As shown, when the multiple anode plates 221a and multiple cathode plates 221b in the electrode assembly 22 are arranged in an alternating stack starting with and ending with the anode plates 221a, each cathode plate 221b can have a main body segment 2221 on both sides. Then, multiple second bending segments 2223 correspond one-to-one with multiple cathode plates 221b, and each second bending segment 2223 is connected to the main body segment 2221 on both sides of its corresponding cathode plate 221b.

[0180] In addition, the connection between the second bending segment 2223 and the two adjacent main segments 2221 can also be by snap-fitting, bonding, sewing, etc., and the specific connection method is not limited.

[0181] In this embodiment, the second bending segment 2223 is located on the side of the main body segment 2221 away from the first wall 201, that is, the second bending segment 2223 is located at the top of the main body segment 2221. The second bending segment 2223 connects the top of the cathode electrode 221b to two adjacent main body segments 2221, so that the main body segment 2221, the second bending segment 2223 and the main body segment 2221 connected in sequence cover the top of the cathode electrode 221b and isolate the top of the cathode electrode 221b from the outer shell 21, thereby reducing the risk of the cathode electrode 221b directly contacting the outer shell 21 or short circuit caused by misalignment between the cathode and anode electrodes due to stacking misalignment.

[0182] Figure 8 As shown Figure 3 Another schematic diagram of the electrode assembly 22 in the battery cell 20 is shown. Figure 8 As shown, in some embodiments, anode plates 221a are provided on both sides of the cathode plate 221b along the stacking direction; the separator 222 also includes an extension section 2224 and a third bending section 2225. The extension section 2224 is located on the side of the outermost anode plate 221a away from the cathode plate 221b. The third bending section 2225 is connected to the adjacent extension sections 2224 and the main body section 2221 on both sides of the outermost anode plate 221a. The third bending section 2225 is located on the side of the extension section 2224 near the first wall 201.

[0183] It should be understood that the cathode electrode 221b has anode electrodes 221a on both sides along the stacking direction. This means that for any cathode electrode 221b in any electrode assembly 22, anode electrodes 221a are provided on both sides along the stacking direction. In other words, anode electrodes 221a are provided at both ends of the multiple anode electrodes 221a and multiple cathode electrodes 221b in the electrode assembly 22 along the stacking direction, while multiple cathode electrodes 221b are alternately arranged between adjacent anode electrodes 221a along the stacking direction. The stacking direction can refer to the thickness direction of the anode electrode 221a or the cathode electrode 221b. Figure 8 Taking the middle electrode assembly 22, which includes 4 anode plates 221a and 3 cathode plates 221b as an example, where the Y direction is the stacking direction, the outermost two sides of the electrode assembly 22 along the Y direction are both anode plates 221a.

[0184] The isolator 222 in this embodiment further includes an extension segment 2224, which is located on the side of the outermost anode electrode 221a away from the cathode electrode 221b. It should be understood that the plane containing the extension segment 2224 is parallel to the plane containing the main body segment 2221. Unlike the main body segment 2221, the extension segment 2224 is located on the outermost side of the electrode assembly 22 along the stacking direction, while the main body segment 2221 is located between adjacent anode electrodes 221a and cathode electrodes 221b of the electrode assembly 22 along the stacking direction. The extension segment 2224 allows the outermost anode electrode 221a along the stacking direction to be spaced apart from the wall in the housing 21 perpendicular to the stacking direction, reducing the risk of short circuits caused by overlap between the anode electrode 221a and the housing 21.

[0185] The isolation member 222 in this embodiment of the application further includes a third bending segment 2225, which connects the adjacent outer extension segment 2224 and the main body segment 2221 on both sides of the outermost anode plate 221a. That is, the third bending segment 2225 connects the outer extension segment 2224 and the main body segment 2221 adjacent to the outer extension segment 2224.

[0186] The third bending segment 2225 is located on the side of the extension segment 2224 near the first wall 201, that is, the third bending segment 2225 is located at the bottom end of the extension segment 2224. The third bending segment 2225 connects the bottom of the outermost anode plate 221a to the adjacent extension segment 2224 and the main body segment 2221. Thus, the sequentially connected extension segment 2224, the third bending segment 2225 and the main body segment 2221 cover the bottom of the outermost anode plate 221a, so that the bottom of the anode plate 221a is separated from the outer shell 21. This further prevents the conductive material that falls off the anode plate 221a from accumulating and contacting the outer shell 21 under the action of gravity, reduces the risk of corrosion of the outer shell 21 due to the conduction between the anode plate 221a and the outer shell 21, and further improves the reliability of the battery cell 20.

[0187] The number of extension segments 2224 can be one or two, and the number of third bend segments 2225 can also be one or two. The number of extension segments 2224 and the number of third bend segments 2225 can be equal or unequal. In some embodiments, refer to... Figure 8 The separator 222 includes two extension segments 2224 and two third bending segments 2225. The two extension segments 2224 are located on the outermost sides of the electrode assembly 22 along the stacking direction. One third bending segment 2225 connects the extension segment 2224 on one side of the outermost sides and the main body segment 2221 adjacent to the extension segment 2224. The other third bending segment 2225 connects the extension segment 2224 on the other side of the outermost sides and the main body segment 2221 adjacent to the extension segment 2224.

[0188] In this embodiment, by providing an extension segment 2224 and a third bending segment 2225 to the outermost anode electrode 221a, the bottoms of all the anode electrodes 221a in the electrode assembly 22 are spaced apart from the outer casing 21. This further prevents conductive material that falls off the anode electrode 221a from accumulating and contacting the outer casing 21 under gravity, reducing the risk of corrosion of the outer casing 21 due to the anode electrode 221a being connected to the outer casing 21. At the same time, the extension segment 2224 can prevent the outermost anode electrode 221a along the stacking direction from overlapping with the outer casing 21, thus preventing a short circuit and further improving the reliability of the battery cell 20.

[0189] It should be understood that, similar to the main body segment 2221, the size of the epitaxial segment 2224 in the height direction Z of the battery cell 20 can be greater than or equal to the size of the electrode in the height direction Z, so that the epitaxial segment 2224 can completely cover the large surface of the electrode perpendicular to the thickness direction, thereby better isolating the anode electrode 221a and the outer shell 21.

[0190] In some embodiments, the extension segment 2224 extends along a first direction and away from the third bending segment 2225, and the two ends of the extension segment 2224 extend outward beyond the two ends of the outermost anode plate 221a in the first direction, respectively. The first direction is perpendicular to the first wall 201.

[0191] It should be understood that the first direction can be as follows: Figure 8 The Z direction is shown. In this embodiment, "outward" can refer to the extension segment 2224 extending outward from the battery cell 20 along the first direction, or it can refer to the extension segment 2224 extending away from the center of symmetry of the extension segment 2224 along the first direction.

[0192] In this embodiment, the length of the extension segment 2224 in the first direction is greater than the length of the outermost anode electrode 221a, and both ends extend beyond the anode electrode 221a, so that the orthographic projection of the anode electrode 221a along its thickness direction is located within the orthographic projection of the extension segment 2224 along its thickness direction. The side of the anode electrode 221a that is close to the outer casing 21 in the thickness direction is completely separated by the extension segment 2224, thereby reducing the risk of the outermost anode electrode 221a directly contacting the outer casing 21, causing electronic conduction and triggering an internal short circuit.

[0193] Furthermore, the dimension of the separator 222 in the length direction X of the battery cell 20 can also be larger than the dimension of the electrode in the length direction X of the battery cell 20. It should be understood that one or more of the main body segment 2221, the first bending segment 2222, the second bending segment 2223, the extension segment 2224, and the third bending segment 2225 in the separator 222 can satisfy this condition, that is, the dimension of any segment in the length direction X is larger than the dimension of the electrode in the length direction X of the battery cell 20.

[0194] For example, the size of the first bending segment 2222 in the length direction X of the battery cell 20 can be greater than or equal to the size of the anode plate 221a in the length direction X, so that the first bending segment 2222 can completely cover the bottom of the corresponding anode plate 221a.

[0195] For example, the dimension of the second bending segment 2223 in the length direction X of the battery cell 20 can be greater than or equal to the dimension of the cathode electrode 221b in the length direction X, so that the second bending segment 2223 can completely cover the top of the corresponding cathode electrode 221b. In this way, the top of the cathode electrode 221b away from the first wall 201 is completely separated from the wall in the outer casing 21 that is opposite to the first wall 201 by the second bending segment 2223, thereby further reducing the risk of the cathode electrode 221b directly contacting the outer casing 21 due to stacking misalignment or short circuit caused by misalignment between the cathode and anode electrodes, and improving the reliability of the battery cell 20.

[0196] For example, the dimension of the third bending segment 2225 in the length direction X of the battery cell 20 can be greater than or equal to the dimension of the anode plate 221a in the length direction X, so that the third bending segment 2225 can completely cover the bottom of the outermost anode plate 221a.

[0197] For example, the dimensions of the main body segment 2221 and the extension segment 2224 in the length direction X of the battery cell 20 can be greater than or equal to the dimensions of the anode electrode 221a in the length direction X, so that the main body segment 2221 can completely isolate two adjacent anode electrodes 221a or the anode electrode 221a from the casing 21.

[0198] like Figure 9 As shown, Figure 9 As shown Figure 8 The diagram shows the electrode assembly 22 along section line A-A'. In some embodiments, the spacer 222 extends along a second direction, and the two ends of the spacer 222 along the second direction extend outward beyond the two ends of the anode plate 221a along the second direction, the second direction being perpendicular to the thickness direction of the anode plate 221a and parallel to the first wall 201.

[0199] It should be understood that the second direction can be as follows: Figure 9 The X direction is shown. In this embodiment, "outward" can refer to the spacer 222 extending outward from the battery cell 20 along the second direction. Figure 9For example, the two ends of the isolator 222 extend outward beyond the two ends of the anode plate 221a along the second direction, that is, the left end of the isolator 222 extends to the left of the anode plate 221a along the direction X, and the right end of the isolator 222 extends to the right of the anode plate 221a along the direction X, so that the length of the isolator 222 in the direction X is greater than the length of the anode plate 221a in the direction X, and the projection of the isolator 222 in the direction Z completely covers the projection of the anode plate 221a in the direction Z.

[0200] In this embodiment, the length of the separator 222 in the second direction is greater than the length of the anode electrode 221a, and both ends extend beyond the anode electrode 221a. This allows the anode electrode 221a to be covered by the separator 222 in multiple directions, thereby separating the bottom of the anode electrode 221a near the first wall 201 from the first wall 201, and separating the anode electrode 221a from the outer casing 21 by the separator 222. This reduces the accumulation of anode particles, especially conductive materials, on one side of the first wall 201 after they fall off from the anode electrode 221a. This reduces the risk of conductive materials causing the anode electrode 221a to overlap with the outer casing 21, making the outer casing 21 conductive and improving the reliability of the battery cell 20.

[0201] In some embodiments, continue to refer to Figure 9 In the second direction, the difference between the length L2 of the separator 222 and the length L1 of the anode plate 221a satisfies: 5mm≤L2-L1≤8mm.

[0202] In this embodiment, the difference between the length of the separator 222 and the length of the anode electrode 221a is set within this range. This ensures that the separator 222 has sufficient length to cover the anode electrode 221a, while avoiding the separator 222 from being too long and affecting the overall energy density.

[0203] In some embodiments, the difference L2-L1 between the length of the separator 222 and the length of the anode plate 221a can be any of the following values ​​or between any of the following values: 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm.

[0204] It should be understood that the lengths of the spacer 222 extending outwards from both ends of the anode plate 221a in the second direction may be equal or unequal. For example, as... Figure 9 As shown, the length of the isolator 222 extending beyond the anode plate 221a in the positive direction of direction X is equal to the length of the isolator 222 extending beyond the anode plate 221a in the negative direction of direction X.

[0205] In some embodiments, in the second direction, the length ΔL of the two ends of the separator 222 extending outward beyond the two ends of the anode plate 221a satisfies: 2.5mm≤ΔL≤4mm.

[0206] In this embodiment, the two ends of the separator 222 extend outward beyond the two ends of the anode electrode 221a by a certain length, so that the projection of the anode electrode 221a onto a plane perpendicular to the thickness direction of the battery cell 20 is approximately located at the center of the projection of the separator 222 onto that plane. This ensures that both ends of the anode electrode 221a along the second direction have sufficient separators 222 to catch particles that may fall off the anode electrode 221a, further reducing the risk of electrical conduction between the anode electrode 221a and the casing 21, and improving the reliability of the battery cell 20.

[0207] In some embodiments, the spacer 222 is integrally formed. It should be understood that integral forming of the spacer 222 can mean that the first bent segment 2222 and the two main body segments 2221 connected thereto of the spacer 222 can be integrally formed; or it can mean that all the first bent segments 2222, the main body segments 2221, and the second bent segments 2223 of the spacer 222 can be integrally formed, thereby making the spacer 222 a continuous diaphragm as a whole. It can also mean that all the extension segments 2224, the third bent segment 2225, the main body segments 2221, the first bent segments 2222, and the second bent segments 2223 of the spacer 222 are integrally formed, thereby making the spacer 222 a continuous diaphragm as a whole.

[0208] It should be understood that the integral molding of the separator 222 can be achieved through multi-layer co-extrusion molding, electrospinning, phase separation pore forming, compression molding, 3D printing, in-situ polymerization, etc.

[0209] In this embodiment, by integrally molding the separator 222, the structural strength and stability of the separator 222 can be improved. Furthermore, the continuous separator 222 simplifies the processing of the electrode assembly 22 and improves the processing efficiency of the battery cell 20.

[0210] Figure 10 A side view of a battery cell according to an embodiment of this application is shown, for example, Figure 10 As shown Figure 3 A schematic diagram of the battery cell 20 along the Y direction; Figure 11 A cross-sectional view of a battery cell according to an embodiment of this application is shown, for example, Figure 11 As shown Figure 10 A schematic diagram of the battery cell 20 along the cross-sectional line B-B'; Figure 12 A partial schematic diagram of a battery cell according to an embodiment of this application is shown, for example, Figure 12 As shown Figure 11A schematic diagram of a portion C of the battery cell 20 shown; Figure 13 As shown Figure 10 The diagram shows a cross-section line D-D' of the battery cell 20. Next, we will combine... Figures 10 to 13 The structure of the battery cell 20 will continue to be described.

[0211] like Figures 10 to 13 As shown, in some embodiments, the battery cell 20 further includes a bottom support plate 24, which is disposed between the electrode assembly 22 and the first wall 201. The bottom support plate 24 is provided with a through groove 241 along the thickness direction of the bottom support plate 24.

[0212] It should be understood that the base plate 24 is disposed at the bottom of the electrode assembly 22, thereby supporting the electrode assembly 22. The base plate 24 is a plate-like structure with a certain thickness, which can raise the electrode assembly 22 so that there is no interference between the electrode assembly 22 and the outer casing 21. In addition, the base plate 24 can be an insulating material or a metal material with an insulating coating on the outer surface.

[0213] The base plate 24 of this application embodiment has a through groove 241 along the thickness direction, that is, along the thickness direction of the base plate 24, the through groove 241 penetrates the entire thickness of the base plate 24, so that the electrolyte can be immersed into the electrode assembly 22 through the through groove 241.

[0214] It should be understood that one or more through slots 241 can be provided, and the through slots 241 can be located at any position on the bottom support plate 24. The embodiments of this application do not limit the number and position of the through slots 241.

[0215] In this embodiment, the base plate 24 supports the electrode assembly 22, reducing the risk of damage to the separator 222 due to electrode deformation or displacement, and further improving the isolation between the electrode and the casing 21. Additionally, the base plate 24 has a through groove 241, allowing the electrolyte to more fully wet the electrode assembly 22, improving the charge / discharge performance of the battery cell 20. Furthermore, because the separator 222 effectively covers the anode electrode 221a, even with the through groove 241 in the base plate 24, the separator 222 in this embodiment can reduce the risk of electrode powder shedding leading to corrosion of the casing 21.

[0216] In some embodiments, continue to refer to Figure 13 The base plate 24 may be provided with a plurality of through slots 241 arranged at intervals along the second direction. In this way, the electrolyte can be more fully wetted into the electrode assembly 22, thereby improving the charge and discharge performance of the battery cell 20.

[0217] It should be understood that the second direction can be the length direction of the battery cell 20, and the multiple through slots 241 can be arranged at intervals along the length direction of the battery cell 20, with the intervals between adjacent through slots 241 being the same or different. For example, multiple through slots 241 arranged at equal intervals can be provided on the bottom plate 24 along the length direction of the battery cell 20. As another example, some of the multiple through slots 241 arranged at equal intervals can be provided on the bottom plate 24 along the length direction of the battery cell 20.

[0218] The through-slot 241 can be located at any position on the base plate 24. For example, the through-slot 241 can be located in the middle of the base plate 24, so that the electrolyte can more fully wet the electrode assembly 22. Or, for example, the through-slot 241 can be located at the edge of the base plate 24 along the thickness direction of the anode plate 221a, so that the electrolyte can fully wet the electrode assembly 22 while better supporting the electrode assembly 22.

[0219] In some embodiments, the bottom support plate 24 is symmetrically provided with through grooves 241 along the thickness direction of the anode electrode 221a, and the through grooves 241 may be located at the edge position of the bottom support plate 24 along the thickness direction of the anode electrode 221a.

[0220] It should be understood that, such as Figure 13 As shown, multiple through slots 241 can be arranged along the X direction, and multiple through slots 241 can also be arranged symmetrically along the Y direction, so that the bottom support plate 24 forms a shape similar to a "fishbone".

[0221] In this embodiment, by symmetrically arranging multiple spaced channels 241, the channels 241 can be distributed at various positions of the bottom support plate 24, thereby promoting the electrolyte to be transported through the multiple channels 241 to the electrode assembly 22 side, more fully wetting the electrode assembly, and improving the cycle performance and service life of the battery cell 20.

[0222] In some embodiments, in the second direction, the length of the through slot 241 is W1 and the distance between two adjacent through slots 241 is W2. Then W1 and W2 can satisfy: 2mm≤W1≤30mm and 2mm≤W2≤20mm, respectively. Or further, W1 and W2 can satisfy: 2mm≤W1≤15mm and 2mm≤W2≤15mm, respectively.

[0223] Setting the length W1 of the through groove 241 in the second direction to be less than or equal to 30 mm, or even further, W1 to be less than or equal to 15 mm, can prevent the strength of the bottom support plate 24 from being reduced due to the excessive length of the through groove 241, provide sufficient support area for the electrode assembly 22, reduce the risk of bending, powder shedding, lithium plating, etc. caused by excessive local pressure on the electrode assembly 22, and improve the reliability of the battery cell 20. Setting the length W1 of the through groove 241 in the second direction to be greater than or equal to 2 mm can allow the electrolyte to pass through the through groove 241 better, thereby more fully wetting the electrode assembly 22. Furthermore, setting the through groove 241 to this length has low process requirements and is simpler to process.

[0224] Similarly, setting the spacing W2 between two adjacent through slots 241 in the second direction to be less than or equal to 20 mm, or even further, W2 to be less than or equal to 15 mm, allows for the setting of more through slots 241, thereby promoting sufficient wetting of the electrolyte; setting the spacing W2 between two adjacent through slots 241 in the second direction to be greater than or equal to 2 mm can improve the support strength of the base plate 24, increase the support area of ​​the electrode assembly 22, reduce the risk of bending, powder shedding, lithium plating, etc. caused by excessive local pressure on the electrode assembly 22, and improve the reliability of the battery cell 20.

[0225] In some embodiments, the length W1 of the through groove 241 in the second direction can be any of the following values ​​or between any of the following values: 1mm, 2mm, 5mm, 10mm, 15mm, 18mm, 20mm, 25mm, 30mm.

[0226] In some embodiments, the spacing W2 between two adjacent through slots 241 in the second direction can be any of the following values ​​or between any of the following values: 2mm, 3mm, 5mm, 10mm, 12mm, 15mm, 18mm, 19mm, 20mm.

[0227] In some embodiments, continue to refer to Figure 13 In the thickness direction of the anode electrode 221a, the length of the bottom support plate 24 is H1, and the length of the through groove 241 is H2. H1 and H2 satisfy: 8mm≤H1-2•H2≤98mm.

[0228] It should be understood that the thickness direction of the anode electrode 221a can be... Figure 13 The direction Y is shown, where 2•H2 indicates that there are two through slots 241 in this direction. That is, in the direction Y, the length of the bottom plate 24 at any position can satisfy the above relationship.

[0229] The above relationship, H1-2•H2, can take any of the following values ​​or be between any of the following values: 8mm, 10mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 98mm.

[0230] In this embodiment, by setting the length relationship between the bottom support plate 24 and the through groove 241 in the thickness direction of the anode electrode 221a to be within this range, on the one hand, it can avoid the through groove 241 being too long and affecting the support strength of the bottom support plate 24. The bottom support plate 24 can provide sufficient support area for the electrode assembly 22, thereby reducing the risk of bending, powder shedding, lithium plating, etc. caused by excessive local pressure on the electrode assembly 22, and improving the reliability of the battery cell 20. On the other hand, the through groove 241 being long enough can improve the wetting degree of the electrode liquid, thereby improving the cycle performance of the battery cell 20.

[0231] It should be understood that the specific dimensions of the base plate 24 can be adjusted according to the dimensions of the battery cell 20, especially the dimensions of the electrode assembly 22 and / or the dimensions of the housing 21. Similarly, the dimensions of the through slot 241 can also be adjusted according to the dimensions of the various components in the battery cell 20, such as the electrode assembly 22, the housing 21, and the base plate 24.

[0232] In some embodiments, the length H1 of the base plate 24 along the thickness direction of the anode electrode 221a satisfies: 15mm≤H1≤100mm, thereby providing sufficient support for the electrode assembly 22 while avoiding occupying too much space inside the battery cell 20 and improving the energy density of the battery cell 20.

[0233] Specifically, the length H1 of the base plate 24 along the thickness direction of the anode electrode 221a can be any of the following values ​​or between any of the following values: 15mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm.

[0234] In some embodiments, the length H2 of the through groove 241 along the thickness direction of the anode electrode 221a satisfies: 3mm≤H2≤10mm, thereby ensuring that the base plate 24 has a certain strength while promoting the full wetting of the electrode assembly 22 by the electrolyte.

[0235] Specifically, the length H2 of the through groove 241 along the thickness direction of the anode electrode 221a can be any of the following values ​​or between any of the following values: 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm.

[0236] In some embodiments, the thickness of the base plate 24 is greater than the radius of the chamfer between the second wall 202 and the first wall 201, where the second wall 202 is a wall in the outer casing 21 adjacent to the first wall 201.

[0237] It should be understood that the second wall 202 is the wall adjacent to the first wall 201 in the outer casing 21; that is, the second wall 202 can be any one of the four walls adjacent to the first wall 201. The thickness of the base plate 24 can, for example, be as follows: Figure 12 The dimensions of the base plate 24 shown are along the Z direction.

[0238] The chamfer between the second wall 202 and the first wall 201 can be either a rounded chamfer or a right-angled chamfer. The second wall 202 and the first wall 201 can be connected by welding, integral stamping, or sheet metal bending.

[0239] During the processing of the casing 21 of the battery cell 20, there is a chamfer between the two different walls, which makes it easy for the outermost electrode in the electrode assembly 22 to touch the chamfer, resulting in damage to the separator 222. Therefore, the thickness of the base plate 24 is greater than the radius of the chamfer between the second wall 202 and the first wall 201, thereby raising the electrode assembly 22 and creating a certain distance between the anode electrode 221a or cathode electrode 221b in the electrode assembly 22 and the chamfer. This reduces the risk of the electrode and separator being damaged due to contact between the electrode and the chamfer, and improves the reliability of the battery cell 20.

[0240] In some embodiments, continue to refer to Figure 13 The battery cell 20 also includes a pressure relief mechanism, which is disposed on the first wall 201. The bottom support plate 24 is also provided with a through hole 242 along the thickness direction of the bottom support plate 24. On a plane perpendicular to the thickness direction of the bottom support plate 24, the projection of the pressure relief mechanism and the projection of the through hole 242 at least partially coincide.

[0241] The thickness direction of the base plate 24 can be the height direction of the battery cell 20, for example, it can be as follows: Figure 12 The direction shown is Z.

[0242] It should be understood that the pressure relief mechanism can be set at any position on the first wall 201, and the through hole 242 can be set at any position on the bottom support plate 24, as long as there is a partial overlap between the pressure relief mechanism and the through hole 242 in the thickness direction of the bottom support plate 24.

[0243] For example, in some embodiments, the center of symmetry of the projection of the pressure relief mechanism coincides with the center of symmetry of the projection of the through hole on a plane perpendicular to the thickness direction of the base plate 24.

[0244] In this embodiment, on one hand, the pressure relief mechanism is disposed on the first wall 201, that is, on the bottom wall of the battery cell 20. Thus, when the pressure relief mechanism is activated, the effluent inside the battery cell 20 can be discharged towards the bottom, thereby preventing high-temperature substances from directly impacting sensitive components above the battery cell 20 and reducing the risk of a chain reaction causing multiple battery cells 20 to fail. On the other hand, the pressure relief mechanism at least partially overlaps with the through hole 242 on the bottom support plate 24. Especially in the event of thermal runaway in the battery cell 20, gases and other substances generated inside the electrode assembly 22 can be discharged through the through hole 242 from the pressure relief mechanism, reducing gas accumulation inside and improving the reliability of the battery cell 20. Furthermore, since the separator 222 can block the electrode from the first wall 201, it can reduce the accumulation of easily detachable substances on the electrode in the pressure relief mechanism, reducing the risk of corrosion of the pressure relief mechanism, especially its weak areas, and improving the reliability of the battery cell 20.

[0245] In some embodiments, continue to refer to Figure 12 The battery cell 20 also includes an insulating member 25, which at least covers the end of the electrode assembly 22 near the first wall 201.

[0246] It should be understood that the insulating member 25 covers the end of the electrode assembly 22 near the first wall 201, that is, the insulating member 25 can be located on the side of the electrode assembly 22 near the first wall 201, and in the direction perpendicular to the first wall 201, the insulating member 25 completely covers the electrode assembly 22, so that all the anode plates 221a and cathode plates 221b in the electrode assembly 22 are isolated from the first wall 201 by the insulating member 25, thereby further reducing the risk that the conductive material on the plates will conduct electricity between the plates and the outer casing 21.

[0247] The insulating component 25 can also extend from both ends of the stacking direction of the anode electrode 221a and the cathode electrode 221b along a direction perpendicular to the first wall 201 away from the first wall 201, thereby covering the anode electrode 221a or the cathode electrode 221b on the outermost sides of the stacking direction. This reduces the risk of the conductive material on the electrode making the electrode and the outer casing 21 conductive, while also isolating the electrode from the wall in the outer casing 21 perpendicular to the stacking direction, thus improving the insulation performance of the battery cell 20.

[0248] The insulating element 25 can also be used to wind the electrode assembly 22 in a direction perpendicular to the second direction, so that the four sides of the electrode assembly 22 parallel to the second direction are covered with the insulating element 25, thereby further isolating the electrode sheet from the four walls of the outer casing 21 parallel to the second direction and improving the insulation performance of the battery cell 20.

[0249] It should be understood that the base plate 24 can be located between the electrode assembly 22 on the side near the first wall 201 and the insulating member 25. That is, the insulating member 25 covers the base plate 24 and the electrode assembly 22 together, thereby reducing the risk that the conductive material on the electrode will conduct electricity between the electrode and the outer shell 21. It can also further fix the base plate 24 and the electrode assembly 22, improve the supporting role of the base plate 24, and reduce the risk that the insulating member 222 will be damaged due to electrode deformation or displacement.

[0250] The base plate 24 can also be disposed between the insulating member 25 and the first wall 201, or the insulating member 25 can be disposed between the electrode assembly 22 and the base plate 24. That is, the base plate 24 supports the electrode assembly 22 covered with the insulating member 25. The insulating member 25 is much less hard than the base plate. As a soft insulating layer, it can absorb the vibration or compression between the base plate 24 and the electrode assembly 22, thereby reducing the damage to the electrode assembly 22 and improving the reliability of the battery cell 20.

[0251] In some embodiments, continue to refer to Figures 3 to 13 The outer casing 21 of the battery cell 20 may include a housing 211 and an end cap 212. The housing 211 has two openings arranged opposite each other along a second direction and includes a first wall 201. The end cap 212 includes a first end cap 212a and a second end cap 212b, which respectively cover the two openings of the housing 211. The first end cap 212a and the second end cap 212b are the two walls with the smallest area of ​​the outer casing 21. The second direction is perpendicular to the thickness direction of the anode electrode 221a and parallel to the first wall 201.

[0252] The housing 21 in this embodiment may include a housing 211, which is a hollow structure having at least one opening. Further, the housing 21 may also include an end cap 212 for covering the opening of the housing 211, so that the electrode assembly 22 can be accommodated within the housing 21.

[0253] It should be understood that the housing 21 in this embodiment is a component for accommodating the electrode assembly 22. The housing 211 can be a hollow structure with an opening at one or more ends. For example, if the housing 211 is a hollow structure with an opening at one end, one end cap 212 can be provided accordingly; if the housing 211 is a hollow structure with openings at opposite ends, two end caps 212 can be provided, with the two end caps 212 respectively covering the openings at both ends of the housing 211.

[0254] The outer casing 21 in this embodiment may further include an end cap 212, which is used to cover the opening of the casing 211 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the end cap 212 can be adapted to the shape of the casing 211, such as... Figure 10As shown, the shell 211 has a cuboid structure, and the end cap 212 has a rectangular plate structure that is adapted to the shell 211.

[0255] like Figure 10 and Figure 11 As shown, the housing 211 of this embodiment has two openings, which are arranged opposite to each other along a second direction, i.e., the second direction can be direction X. The end cap 212 includes a first end cap 212a and a second end cap 212b, which are respectively covered by the two openings. The first end cap 212a and the second end cap 212b are the walls with the smallest area in the housing 21. That is, the anode electrode 221a and the cathode electrode 221b in the electrode assembly 22 are alternately stacked along the thickness direction Y of the battery cell 20. At the same time, the anode electrode 221a and the cathode electrode 221b can extend along the length direction X of the battery cell 20, and the separator 222 can also extend along the length direction X of the battery cell 20, thereby covering the longer part of the electrode, further reducing the risk of the conductive material overlapping the electrode with the housing 21, and improving the reliability of the battery cell 20.

[0256] It should be understood that the material of the housing 211 may include one or more materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the end cap 212 may also be one or more materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the end cap 212 may be the same as or different from that of the housing 211; the materials of different walls of the housing 211 may also be the same or different.

[0257] In some embodiments, the battery cell 20 further includes a first electrode terminal 23a and a second electrode terminal 23b. The first electrode terminal 23a is disposed on the first end cover 212a, and the second electrode terminal 23b is disposed on the second end cover 212b. The electrode assembly 22 has a first tab and a second tab, which are respectively located at both ends of the electrode assembly 22 along a second direction. The first tab connects the anode plate 221a and the first electrode terminal 23a, and the second tab connects the cathode plate 221b and the second electrode terminal 23b.

[0258] In this embodiment, the first tab and the second tab are respectively disposed at both ends of the electrode assembly 22 along the second direction. Since the insulating member 222 is disposed on the large surface of the electrode sheet and at both ends of the electrode assembly 22 in the direction perpendicular to the first wall 201, that is, the first tab and the second tab are led out from the two ends of the electrode sheet where the insulating member 222 is not disposed, the risk of the tab puncturing the insulating member 222 can be reduced and the insulating effect of the insulating member 222 can be improved.

[0259] According to some embodiments of this application, this application also provides a battery device 10, including a housing 11 and a plurality of battery cells 20 as described in any of the above embodiments. The housing 11 has a hollow interior, and the plurality of battery cells 20 are housed within the housing 11.

[0260] In some embodiments, the housing 11 includes an upper housing 111 and a lower housing 112. The lower housing 112 has an opening, and the upper housing 111 covers the opening. The lower housing 112 is used to support a plurality of battery cells 20. The electrode assembly 22 of the battery cell 20 includes an anode electrode 221a, a cathode electrode 221b, and a separator 222. The separator 222 covers the end of the anode electrode 221a near the lower housing 112.

[0261] It should be understood that multiple battery cells 20 are placed inside the housing 11, and the lower housing 112 supports the multiple battery cells 20, that is, the bottom walls of the multiple battery cells 20 are set towards the lower housing 112.

[0262] The way the separator 222 covers the end of the anode electrode 221a near the lower housing 112 can be any of the separator 222 schemes described above. It should be understood that regardless of how the battery cell 20 is placed in the housing, the separator 222 always covers the area of ​​the anode electrode 221a near the end of the lower housing 112 along the direction of gravity, thereby reducing the risk of easily detachable conductive material from the electrode accumulating on the outer casing 21 of the battery cell 20 and causing corrosion of the outer casing 21, and improving the reliability of the entire battery device 10.

[0263] According to some embodiments of this application, this application also provides an electrical device, including a battery cell 20 or a battery device 10 as described in any of the above embodiments, wherein the battery cell 20 or the battery device 10 is used to provide electrical energy.

[0264] The electrical equipment can be any of the aforementioned devices or systems that utilize battery devices.

[0265] According to some embodiments of this application, see Figures 3 to 13This application provides a battery cell 20, including: a housing 21 having a receiving space and a first wall 201 located at the bottom of the receiving space in the direction of gravity; and an electrode assembly 22 housed in the receiving space, the electrode assembly 22 including a plurality of anode plates 221a, a plurality of cathode plates 221b, and a separator 222, wherein the anode plates 221a and cathode plates 221b are sequentially and alternately stacked, and the end of the anode plate 221a near the first wall 201 extends beyond the cathode plate. At the end of sheet 221b near the first wall 201, the separator 222 includes a main body segment 2221 and a first bending segment 2222. The main body segment 2221 is disposed between adjacent anode sheet 221a and cathode sheet 221b. The first bending segment 2222 is connected to two adjacent main body segments 2221 located on both sides of the anode sheet 221a. The first bending segment 2222 is located on the side of the main body segment 2221 near the first wall 201. The diameter φ1 of the anode particles on the anode sheet 221a is larger than the pore diameter φ2 of the separator 222.

[0266] The spacer 222 also includes a second bent section 2223; the second bent section 2223 is connected to two adjacent main body sections 2221 located on both sides of the cathode electrode 221b, and the second bent section 2223 is located on the side of the main body section 2221 away from the first wall 201.

[0267] The isolation component 222 is integrally molded.

[0268] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: The outer shell (21) has a receiving space, and the outer shell (21) has a first wall (201) located at the bottom of the receiving space in the direction of gravity; An electrode assembly (22) is housed within the receiving space. The electrode assembly (22) includes multiple anode plates (221a), multiple cathode plates (221b), and a spacer (222). The anode plates (221a) and the cathode plates (221b) are arranged in an alternating layer. The end of the anode plate (221a) near the first wall (201) extends beyond the end of the cathode plate (221b) near the first wall (201). The spacer... (222) includes a main body segment (2221) and a first bending segment (2222), the main body segment (2221) being disposed between adjacent anode plates (221a) and cathode plates (221b), the first bending segment (2222) being connected to two adjacent main body segments (2221) located on both sides of the anode plate (221a), the first bending segment (2222) being located on the side of the main body segment (2221) closer to the first wall (201); Wherein, the particle size φ1 of the anode particles on the anode electrode (221a) is greater than the pore diameter φ2 of the separator (222); The particle size φ1 of the anode particles on the anode electrode (221a) satisfies: 8μm≤φ1≤37μm, and the pore diameter φ2 of the separator (222) satisfies: 50nm≤φ2≤300nm; The battery cell also includes a bottom support plate (24), which is located between the electrode assembly (22) and the first wall (201). The bottom support plate (24) is provided with a through groove (241) along the thickness direction of the bottom support plate (24). The bottom support plate (24) is provided with a plurality of through slots (241) arranged at intervals along the second direction. In the second direction, the length of the through slot (241) is W1 and the distance between two adjacent through slots (241) is W2. W1 and W2 satisfy: 2mm≤W1≤30mm and 2mm≤W2≤20mm, respectively. The second direction is perpendicular to the thickness direction of the anode electrode (221a) and parallel to the first wall (201). The bottom support plate (24) is symmetrically provided with the through groove (241) along the thickness direction of the anode electrode (221a), and the through groove (241) is located at the edge of the bottom support plate (24) along the thickness direction of the anode electrode (221a). In the thickness direction of the anode electrode (221a), the length of the bottom support plate (24) is H1, and the length of the through groove (241) is H2. H1 and H2 satisfy: 8mm≤H1-2•H2≤98mm.

2. The battery cell according to claim 1, characterized in that, The anode electrode (221a) has an adhesive, and the ratio R of the adhesive content to the anode particle content satisfies: 0.5% ≤ R ≤ 1.2%.

3. The battery cell according to claim 1, characterized in that, The main body segment (2221) extends along a first direction and away from the first bent segment (2222), and the two ends of the main body segment (2221) extend outward beyond the two ends of the anode plate (221a) along the first direction, and the first direction is perpendicular to the first wall (201).

4. The battery cell according to claim 1, characterized in that, The spacer (222) also includes a second bent section (2223); The second bent segment (2223) is connected to two adjacent main body segments (2221) located on both sides of the cathode electrode (221b), and the second bent segment (2223) is located on the side of the main body segment (2221) away from the first wall (201).

5. The battery cell according to claim 1, characterized in that, The cathode electrode (221b) has the anode electrode (221a) on both sides along the stacking direction. The separator (222) further includes an extension segment (2224) and a third bending segment (2225). The extension segment is located on the side of the outermost anode electrode (221a) away from the cathode electrode (221b). The third bending segment (2225) is connected to the adjacent extension segments (2224) and the main body segment (2221) on both sides of the outermost anode electrode (221a). The third bending segment (2225) is located on the side of the extension segment (2224) near the first wall (201).

6. The battery cell according to claim 5, characterized in that, The extension segment (2224) extends along a first direction and away from the third bending segment (2225). The two ends of the extension segment (2224) extend outward beyond the two ends of the anode electrode (221a) along the first direction. The first direction is perpendicular to the first wall (201).

7. The battery cell according to claim 1, characterized in that, The isolator (222) extends along the second direction, and the two ends of the isolator (222) extend outward beyond the two ends of the anode plate (221a) along the second direction.

8. The battery cell according to claim 7, characterized in that, In the second direction, the difference between the length L2 of the separator (222) and the length L1 of the anode plate (221a) satisfies: 5mm≤L2-L1≤8mm.

9. The battery cell according to claim 8, characterized in that, In the second direction, the length ΔL of the two ends of the separator (222) extending outward beyond the two ends of the anode electrode (221a) satisfies: 2.5mm≤ΔL≤4mm.

10. The battery cell according to claim 1, characterized in that, The isolation component (222) is integrally formed.

11. The battery cell according to any one of claims 1 to 10, characterized in that, The thickness of the base plate (24) is greater than the radius of the chamfer between the second wall (202) and the first wall (201), and the second wall (202) is the wall in the outer shell (21) adjacent to the first wall (201).

12. The battery cell according to claim 1, characterized in that, The battery cell also includes a pressure relief mechanism, which is disposed on the first wall (201). The bottom support plate (24) is also provided with a through hole (242) along the thickness direction of the bottom support plate (24). On a plane perpendicular to the thickness direction of the bottom support plate (24), the projection of the pressure relief mechanism and the projection of the through hole (242) at least partially coincide.

13. The battery cell according to any one of claims 1 to 10, characterized in that, The battery cell also includes an insulating element (25) that covers at least the end of the electrode assembly (22) near the first wall (201).

14. The battery cell according to any one of claims 1 to 10, characterized in that, The outer casing (21) includes: The housing (211) has two openings disposed opposite each other along a second direction, and the housing (211) includes the first wall (201). End cap (212), the end cap (212) includes a first end cap (212a) and a second end cap (212b), the first end cap (212a) and the second end cap (212b) respectively cover the two openings of the housing (211), the first end cap (212a) and the second end cap (212b) are the two walls of the outer shell (21) with the smallest area; The second direction is perpendicular to the thickness direction of the anode electrode (221a) and parallel to the first wall (201).

15. The battery cell according to claim 14, characterized in that, The battery cell further includes a first electrode terminal (23a) and a second electrode terminal (23b), wherein the first electrode terminal (23a) is disposed on the first end cap (212a) and the second electrode terminal (23b) is disposed on the second end cap (212b); The electrode assembly (22) has a first tab and a second tab, which are located at the two ends of the electrode assembly (22) along the second direction, respectively. The first tab connects the anode plate (221a) and the first electrode terminal (23a), and the second tab connects the cathode plate (221b) and the second electrode terminal (23b).

16. A battery device, characterized in that, include: The box (11) has a hollow interior; A plurality of battery cells (20) according to any one of claims 1 to 15, wherein the plurality of battery cells (20) are housed within the housing (11).

17. The battery device according to claim 16, characterized in that, The housing (11) includes an upper housing (111) and a lower housing (112), the lower housing (112) having an opening, the upper housing (111) covering the opening, and the lower housing (112) supporting a plurality of battery cells (20). The electrode assembly (22) of the battery cell (20) includes an anode electrode (221a), a cathode electrode (221b), and a separator (222), wherein the separator (222) covers the end of the anode electrode (221a) near the lower housing (112).

18. An electrical appliance, characterized in that, Includes a battery cell according to any one of claims 1 to 15 or a battery device according to claim 16 or 17, wherein the battery cell or the battery device is used to provide electrical energy.

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