Battery cell, battery device and electric device

Abstract

Provided in the present application are a battery cell, a battery device and an electric device. The battery cell comprises a casing and a reinforcing portion. The casing comprises a wall portion, which has a weakened portion, the weakened portion being annular and configured to be at least partially broken during pressure relief of the battery cell. The wall portion has a first surface along the thickness of the wall portion. The reinforcing portion is disposed on the first surface, the reinforcing portion is of an annular structure, and the weakened portion is arranged around the outer side of the reinforcing portion. Since the weakened portion is annular and the reinforcing portion is of an annular structure, the weakened portion being arranged around the outer side of the reinforcing portion, the reinforcement effects of the reinforcing portion on all positions of the weakened portion are relatively uniform, so that the weakened portion is more likely to be completely broken during pressure relief of the battery cell, thereby creating a relatively large opening and facilitating rapid pressure release of the battery cell. When the region of the wall portion located on the inner side the reinforcing portion is subjected to a force and deforms, the reinforcing portion can provide a buffering effect, so as to reduce the stress transmitted to the weakened portion, thereby lowering the risk of premature valve opening in the battery cell, and helping prolong the service life and improve the reliability of the battery cell.

Description

Battery cells, battery packs and electrical devices Technical Field

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

[0002] Batteries are widely used in the new energy field, such as in electric vehicles and new energy vehicles, which have become a new trend in the automotive industry. The development of battery technology must consider multiple design factors simultaneously, such as energy density, discharge capacity, and charge / discharge rate. Additionally, battery lifespan must be considered. However, current batteries have relatively short lifespans. Summary of the Invention

[0003] The purpose of this application is to provide a battery cell, a battery device, and an electrical device, which aims to improve the problem of short battery life in related technologies.

[0004] In a first aspect, embodiments of this application provide a battery cell, the battery cell including a shell and a reinforcing portion, the shell including a wall portion, the wall portion having a weak portion, the weak portion being annular, the weak portion being configured to be at least partially destroyed when the battery cell is depressurized, the wall portion having a first surface along the thickness direction of the wall portion; the reinforcing portion being disposed on the first surface, the reinforcing portion having an annular structure, and the weak portion being disposed around the outside of the reinforcing portion.

[0005] In the above technical solution, a reinforcing portion is provided on the first surface of the wall in the thickness direction. This reinforcing portion strengthens the wall, improving its resistance to deformation and fatigue, reducing the risk of fatigue-induced failure, and thus extending its service life, thereby increasing the service life of the battery cell. Furthermore, the weak point is annular, and the reinforcing portion is also annular, surrounding the outside of the reinforcing portion. On one hand, the reinforcing effect of the reinforcing portion on various locations of the weak point is relatively uniform, making it easier for the weak point to be completely destroyed during battery cell depressurization. This allows the area inside the weak point of the wall to easily detach from the wall, creating a larger opening through which the discharge material inside the battery cell can be quickly depressurized, improving the timeliness of battery cell depressurization. On the other hand, when the area inside the reinforcing portion of the wall deforms under stress, the reinforcing portion acts as a buffer, reducing the stress transmitted to the weak point, thereby reducing the risk of premature valve opening in the battery cell and improving the battery cell's lifespan and reliability.

[0006] As an optional technical solution in this application embodiment, the distance between the weak part and the reinforcing part in the direction perpendicular to the thickness direction of the wall is L, which satisfies: 1mm≤L≤4mm.

[0007] In the above technical solutions, when L ≥ 1 mm, the distance between the weak part and the reinforcing part is relatively large in the direction perpendicular to the thickness of the wall. This makes it less likely that the reinforcing part will affect the weak part, thus reducing the risk of premature valve opening in the battery cells and improving their lifespan and reliability. When L ≤ 4 mm, the distance between the weak part and the reinforcing part is not too large in the direction perpendicular to the thickness of the wall, resulting in a larger area of ​​the wall inside the reinforcing part. This allows the reinforcing part to provide better buffering, reducing the risk of premature valve opening in the battery cells and improving their lifespan and reliability. Therefore, when 1 mm ≤ L ≤ 4 mm, the battery cells have a longer lifespan and higher reliability.

[0008] As an optional technical solution in this application embodiment, 2mm≤L≤3mm.

[0009] In the above technical solutions, when L ≥ 2mm, the distance between the weak part and the reinforcing part is larger in the direction perpendicular to the wall thickness. This makes it less likely that the reinforcing part will be affected, thus reducing the risk of premature valve opening in battery cells and improving their lifespan and reliability. When L ≤ 3mm, the distance between the weak part and the reinforcing part is not too large in the direction perpendicular to the wall thickness, resulting in a larger area of ​​the wall inside the reinforcing part. This allows the reinforcing part to provide better buffering, further reducing the risk of premature valve opening in battery cells and improving their lifespan and reliability. Therefore, when 2mm ≤ L ≤ 3mm, the battery cell has a longer lifespan and higher reliability.

[0010] As an optional technical solution in this application embodiment, in the direction perpendicular to the thickness direction of the wall portion, the distance between the weak portion and the reinforcing portion is less than the distance from the reinforcing portion to the central axis of the weak portion.

[0011] In the above technical solution, in the direction perpendicular to the thickness of the wall, the distance between the weak part and the reinforcing part is less than the distance from the central axis of the reinforcing part to the weak part, which makes the area of ​​the wall located inside the reinforcing part larger, so that the reinforcing part can play a better buffering role, reduce the risk of premature valve opening of the battery cell, and help improve the life and reliability of the battery cell.

[0012] As an optional technical solution in this application embodiment, both the weak part and the reinforcing part are annular, and the distance between the axis of the weak part and the axis of the reinforcing part is less than or equal to 1 mm.

[0013] In the above technical solution, both the weak part and the reinforcing part are annular, and the distance between the axis of the weak part and the axis of the reinforcing part is less than or equal to 1mm. In this way, the weak part and the reinforcing part are roughly coaxial, so that the reinforcing effect of the reinforcing part on each position of the weak part is more even. When the battery cell is depressurized, the force on each position of the weak part is more uniform, making it easier for the weak part to be completely destroyed when the battery cell is depressurized. This makes it easier for the area of ​​the wall located inside the weak part to completely detach from the wall, opening a larger opening. The discharge inside the battery cell can be quickly depressurized through this opening, which helps to improve the timeliness of depressurization of the battery cell.

[0014] As an optional technical solution in this application embodiment, the axis of the weak part and the axis of the reinforcing part coincide.

[0015] In the above technical solution, both the weak part and the reinforcing part are annular, and the axis of the weak part coincides with the axis of the reinforcing part. In this way, the weak part and the reinforcing part are coaxially arranged, so that the reinforcing effect of the reinforcing part on each position of the weak part is most similar. When the battery cell is depressurized, the force on each position of the weak part is more uniform, making it easier for the weak part to be completely destroyed when the battery cell is depressurized. This makes it easier for the area of ​​the wall located inside the weak part to completely detach from the wall, opening a larger opening. The discharge inside the battery cell can be quickly depressurized through this opening, which helps to improve the timeliness of depressurization of the battery cell.

[0016] As an optional technical solution in this application embodiment, the wall portion has a second surface disposed opposite to the first surface, the wall portion is provided with a first groove, the first groove is annular, the first groove is recessed from the second surface in a direction close to the first surface, and the reinforcing portion protruding from the first surface is formed at the position of the wall portion corresponding to the first groove.

[0017] In the above technical solution, during molding, a first groove can be formed on the second surface by stamping, thereby forming a reinforcing part protruding from the first surface. The molding method of the reinforcing part is simple. The setting of the first groove makes the wall part form a recessed structure at the location where the reinforcing part is set, so that the reinforcing part has better resistance to deformation and improves the reinforcing effect of the reinforcing part on the wall part.

[0018] As an optional technical solution in this application embodiment, along the thickness direction of the wall portion, the reinforcing portion has a third surface furthest from the first surface, the distance between the bottom surface of the first groove and the third surface is H1, and the distance between the first surface and the second surface is H2, satisfying: 0.5≤H1 / H2≤1.5.

[0019] In the above technical solution, when H1 / H2≥0.5, the distance between the bottom surface of the first groove and the third surface is relatively large along the thickness direction of the wall, resulting in a better strengthening and buffering effect for the reinforcing part. When H1 / H2≤1.5, the distance between the bottom surface of the first groove and the third surface is not too large along the thickness direction of the wall, which helps to reduce the occupancy of the reinforcing part on the internal space of the battery cell or battery device, and helps to improve the energy density of the battery cell or battery device. When 0.5≤H1 / H2≤1.5, the distance between the bottom surface of the first groove and the third surface is relatively close to the distance between the first surface and the second surface along the thickness direction of the wall, which facilitates the processing of the reinforcing part by stamping and can balance the strengthening effect, buffering effect and energy density of the battery cell.

[0020] As an optional technical solution in this application embodiment, 0.8≤H1 / H2≤1.2.

[0021] In the above technical solutions, when H1 / H2≥0.8, the distance between the bottom surface of the first groove and the third surface is larger along the thickness direction of the wall, resulting in better reinforcement and buffering effects. When H1 / H2≤1.2, the distance between the bottom surface of the first groove and the third surface is not too large along the thickness direction of the wall, which helps to reduce the occupancy of the reinforcement on the internal space of the battery cell or battery device, thus improving the energy density of the battery cell or battery device. When 0.8≤H1 / H2≤1.2, the distance between the bottom surface of the first groove and the third surface is closer to the distance between the first and second surfaces along the thickness direction of the wall, making it easier to process the reinforcement by stamping and better balancing the reinforcement effect, buffering effect, and energy density of the battery cell.

[0022] As an optional technical solution in this application embodiment, along the thickness direction of the wall portion, the height of the reinforcing portion protruding from the first surface is H3, and the distance between the first surface and the second surface is H2, satisfying: 1 / 3≤H3 / H2≤1.

[0023] In the above technical solution, when H3 / H2 ≥ 1 / 3, the height of the reinforcing part protruding from the first surface along the thickness direction of the wall is relatively high, and the reinforcing part has a good strengthening and buffering effect. When H3 / H2 ≤ 1, the height of the reinforcing part protruding from the first surface along the thickness direction of the wall is not too high. On the one hand, when the reinforcing part is processed by stamping, it is not easy to cause the material to be overstretched and form a weak position. On the other hand, it is beneficial to reduce the occupancy of the reinforcing part on the internal space of the battery cell or the battery device, which is beneficial to improving the energy density of the battery cell or the battery device. When 1 / 3 ≤ H3 / H2 ≤ 1, the strengthening effect, buffering effect of the reinforcing part and the energy density of the battery cell can be balanced.

[0024] As an optional technical solution in this application embodiment, the wall portion is provided with a second groove, and the bottom wall of the second groove forms the weak portion; along the thickness direction of the wall portion, the bottom surface of the first groove is closer to the first surface than the bottom surface of the second groove.

[0025] In the above technical solution, by making the bottom surface of the first groove closer to the first surface along the thickness direction of the wall than the bottom surface of the second groove, when the area of ​​the wall located inside the reinforcement is subjected to force deformation, the reinforcement can play a better buffering role, reducing the stress transmitted to the weak part, thereby reducing the risk of premature valve opening of the battery cell, which is beneficial to improving the life and reliability of the battery cell.

[0026] As an optional technical solution in this application embodiment, the reinforcing part has a first sidewall and a first bottom wall. The first sidewall surrounds the first bottom wall, and the first sidewall and the first bottom wall together define the first groove. The thickness of the first sidewall is H4, and the distance between the first surface and the second surface along the thickness direction of the wall is H2, satisfying: H4≤H2.

[0027] In the above technical solution, when H4≤H2, the thickness of the first sidewall does not exceed the distance between the first surface and the second surface, which can simplify the forming process. The reinforcing part can be formed by stamping, and the forming method is simple.

[0028] As an optional technical solution in this application embodiment, along the thickness direction of the wall portion, the thickness of the first bottom wall is H1, and the distance between the first surface and the second surface is H2, satisfying: H1≤H2.

[0029] In the above technical solution, when H1≤H2, the thickness of the first bottom wall does not exceed the distance between the first surface and the second surface, which can simplify the forming process. The reinforcing part can be formed by stamping, and the forming method is simple.

[0030] As an optional technical solution in this application embodiment, the wall portion is provided with a second groove, and the bottom wall of the second groove forms the weak portion.

[0031] In the above technical solution, a weak part is formed on the wall by opening a second groove on the wall. When the battery cell is depressurized, the wall cracks along at least a part of the second groove. This method is simple, convenient, and low in cost.

[0032] As an optional technical solution in this application embodiment, the second groove is disposed on the first surface.

[0033] In the above technical solution, the reinforcing part protrudes from the first surface, and the second groove is disposed on the first surface. That is, the reinforcing part and the second groove are disposed on the same surface. When the reinforcing part and the second groove are processed by stamping, the wall is stamped from both sides of the wall, so that the wall is not easily deformed to one side.

[0034] As an optional technical solution in this application embodiment, the first surface faces the interior of the outer shell.

[0035] In the above technical solution, since the reinforcing part is disposed on the first surface, which faces the interior of the outer casing, the reinforcing part can utilize the internal space of the battery cell and will not occupy the external space of the battery cell. In the embodiment where the second groove is disposed on the first surface, the first surface faces the interior of the outer casing, so that the second groove faces the interior of the battery cell. The second groove is not exposed to the exterior of the battery cell, reducing the risk of oxidation of the wall portion where the second groove is disposed due to exposure to the exterior of the battery cell.

[0036] As an optional technical solution in this application embodiment, the battery cell includes an electrode assembly, which is housed within the housing; the wall includes a wall body and an abutment portion, the abutment portion is disposed around the outer edge of the wall body, and along the thickness direction of the wall, the abutment portion protrudes from the wall body in a direction close to the electrode assembly and directly or indirectly abuts against the electrode assembly, and the wall body includes the weak portion.

[0037] In the above technical solution, the abutment portion of the wall directly or indirectly abuts against the electrode assembly, and the abutment portion can restrict the electrode assembly and reduce the risk of the electrode assembly moving inside the housing.

[0038] As an optional technical solution in this application embodiment, the outer shell includes a second sidewall, which surrounds the wall portion. Along the thickness direction of the wall portion, the wall portion is located at one end of the second sidewall. A first flow channel is formed between the electrode assembly and the second sidewall. The abutment portion and the wall body together define a flow space. The abutment portion is provided with a second flow channel, which connects the flow space and the first flow channel.

[0039] In the above technical solution, since the abutment part is provided with a second flow channel, which connects the flow space and the first flow channel, when the battery cell thermally runs away, the emissions generated by the electrode assembly flow into the first flow channel. The emissions can then flow quickly into the flow space through the second flow channel on the abutment part, causing the air pressure in the flow space to rise rapidly and reach the burst pressure quickly. This allows the weak parts to be destroyed in time, shortens the time from the battery cell thermally running away to the battery cell starting to depressurize, reduces the risk of battery cell explosion and fire, and effectively improves the reliability of the battery cell.

[0040] As an optional technical solution in this application embodiment, the wall portion further includes an edge portion, which is disposed around the outer edge of the abutment portion, and the edge portion abuts against one end of the second sidewall in the direction of the wall portion pointing towards the electrode assembly.

[0041] In the above technical solution, the abutment between the edge portion and the second sidewall can limit the wall portion and restrict its movement in the direction close to the electrode assembly.

[0042] As an optional technical solution in this application embodiment, along the thickness direction of the wall portion, the wall body has a fourth surface and a fifth surface disposed opposite to each other. The fourth surface faces the electrode assembly. The wall body is provided with a recess. The recess is recessed from the fifth surface in a direction close to the fourth surface, and a protrusion is formed on the wall body at a position corresponding to the recess, protruding from the fourth surface. The surface of the protrusion facing the electrode assembly is the first surface. Along the thickness direction of the wall portion, the orthographic projection of the weak portion is located in the recess.

[0043] In the above technical solution, the recessed part creates a certain distance between the area inside the weak part of the wall and the fifth surface. When the fifth surface contacts the external component, it can reduce the influence of the external component on the area inside the weak part of the wall. This allows the area inside the weak part of the wall to open outward when the battery cell is depressurized, reducing the risk that the area inside the weak part of the wall will not be able to open normally due to the obstruction of the external component.

[0044] As an optional technical solution in this application embodiment, the outer shell includes a housing and an end cap, the housing has an opening, the end cap closes the opening, and the end cap is the wall portion.

[0045] In the above technical solution, the end cap is a wall portion, which makes the end cap have a weak part, reducing the difficulty of molding or installing the weak part.

[0046] As an optional technical solution in this application embodiment, the battery cell is a cylindrical battery cell, and the thickness direction of the wall portion is parallel to the axial direction of the cylindrical battery cell.

[0047] Secondly, embodiments of this application also provide a battery device, which includes the aforementioned battery cell.

[0048] As an optional technical solution in this application embodiment, along the thickness direction of the wall portion, the wall portion has a fourth surface and a fifth surface disposed opposite to each other. The fourth surface faces the interior of the outer casing. The wall portion is provided with a recess. The recess is recessed from the fifth surface in a direction close to the fourth surface, and a protrusion is formed on the wall portion at a position corresponding to the recess, protruding from the fourth surface. The surface of the protrusion facing the interior of the outer casing is the first surface. Along the thickness direction of the wall portion, the orthographic projection of the weak portion is located in the recess. The battery device also includes a housing. The battery cell is housed in the housing. The battery cell is fixed to the housing by an adhesive layer. The adhesive layer is at least partially housed in the recess.

[0049] In the above technical solution, by having the adhesive layer at least partially accommodated within the recess, on the one hand, the space occupied by the adhesive layer inside the casing can be reduced, thereby increasing the energy density of the battery device. On the other hand, having the adhesive layer at least partially accommodated within the recess results in a larger contact area between the adhesive layer and the wall, which can improve the bonding strength between the battery cell and the casing.

[0050] As an optional technical solution in this application embodiment, the wall portion is provided with a first groove, the first groove is annular, the first groove is recessed from the bottom surface of the recess along the direction close to the first surface, and the reinforcing portion protruding from the first surface is formed at the position of the wall portion corresponding to the first groove.

[0051] In the above technical solution, during molding, a first groove can be formed on the bottom surface of the recess by stamping, thereby forming a reinforcing part protruding from the first surface. The molding method of the reinforcing part is simple. The setting of the first groove makes the wall part form a recessed structure at the location of the reinforcing part, which makes the reinforcing part have better resistance to deformation and improves the reinforcing effect of the reinforcing part on the wall part.

[0052] As an optional technical solution in this application embodiment, a portion of the adhesive layer is accommodated within the first groove.

[0053] In the above technical solution, by accommodating a portion of the adhesive layer within the first groove, on the one hand, the space occupied by the adhesive layer inside the casing can be reduced, thereby increasing the energy density of the battery device. On the other hand, since the adhesive layer is at least partially accommodated within the first groove, the contact area between the adhesive layer and the wall is larger, which can improve the bonding strength between the battery cell and the casing.

[0054] As an optional technical solution in this application embodiment, the first groove does not contain the adhesive layer.

[0055] In the above technical solution, the first groove does not contain an adhesive layer, and the adhesive layer does not easily prevent the weak part from cracking, allowing the battery cell to release pressure smoothly, which is beneficial to improving the timeliness of pressure release of the battery cell. Thirdly, embodiments of this application also provide an electrical device, which includes the aforementioned battery cell, and the battery cell is used to provide electrical energy to the electrical device. Attached Figure Description

[0056] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0057] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0058] Figure 2 is an exploded view of a battery device provided in some embodiments of this application;

[0059] Figure 3 is an exploded view of a single battery cell provided in some embodiments of this application;

[0060] Figure 4 is a schematic diagram of the wall structure provided in some embodiments of this application;

[0061] Figure 5 is a top view of the wall portion provided in some embodiments of this application;

[0062] Figure 6 is a cross-sectional view of position AA in Figure 5;

[0063] Figure 7 is an enlarged view of position B in Figure 6;

[0064] Figure 8 is a cross-sectional view of a battery cell provided in some embodiments of this application.

[0065] Icons: 10-Box body; 11-First box body; 12-Second box body; 20-Battery cell; 21-Outer shell; 211-Shell; 2111-Second side wall; 2112-Second bottom wall; 2113-First flow channel; 212-End cap; 213-Wall portion; 2131-Weak portion; 21311-First surface; 21312-Second surface; 2132-Second groove; 2133-First groove; 2134-Abutting portion; 21341-Body portion; 21342-Protrusion 2135-Wall body; 21351-Recess; 21352-Protrusion; 21353-Fourth surface; 21354-Fifth surface; 2136-Edge portion; 2137-Flow guiding space; 2138-Second flow guiding channel; 22-Reinforcing portion; 221-Third surface; 222-First bottom wall; 223-First side wall; 23-Electrode assembly; 24-Electrode terminal; 25-Current collector; 100-Battery device; 200-Controller; 300-Motor; 1000-Vehicle. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0067] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0068] In this application, the reference to "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 in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0069] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0070] In this application, 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 existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0071] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0072] In this application, "multiple" means two or more (including two).

[0073] 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.

[0074] Battery cells include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0075] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. 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, reduces the risk of short circuits while allowing active ions to pass through.

[0076] 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.

[0077] 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.

[0078] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0079] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials in battery cells may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05At least one of O2 and its modified compounds.

[0080] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0081] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0082] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be nickel foam, copper foam, aluminum foam, foam alloy, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0083] 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.

[0084] 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.

[0085] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0086] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0087] In some embodiments, the separator is a separator membrane. The separator membrane can be any known porous structure separator membrane with good chemical and mechanical stability.

[0088] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0089] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0090] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0091] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0092] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0093] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0094] In some implementations, the electrode assembly is a stacked structure.

[0095] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0096] 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.

[0097] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0098] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0099] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0100] In some implementations, the electrode assembly may be flat or polygonal in shape.

[0101] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0102] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, or a composite metal (such as a copper-aluminum composite housing).

[0103] In some embodiments, the housing can be a sealed structure or a non-sealed structure. As an example, when the housing is a sealed structure, it can protect the electrode assembly and prevent, to some extent, electrolyte leakage. When the housing is a non-sealed structure, it can still protect the electrode assembly, and a sealing bag may be included between the housing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film.

[0104] As an example, a battery cell can be a prismatic battery cell or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0105] 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, which are connected in series, parallel, or mixed connections via a busbar.

[0106] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging multiple battery cells and fixing them together to form an independent module.

[0107] As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0108] In some embodiments, the battery device may be a battery pack, which may include a housing and one or more individual battery cells housed within the housing.

[0109] 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.

[0110] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0111] As an example, the enclosure may include a first enclosure body and a second enclosure body. The first enclosure body and the second enclosure body are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, which can be either sealed or unsealed. The first enclosure body may be a top cover or a bottom plate.

[0112] 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.

[0113] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0114] In some embodiments, the battery device refers to an energy storage device, which includes a housing with a door on at least one side. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0115] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0116] The development of battery technology must consider multiple design factors simultaneously, such as energy density, discharge capacity, and charge / discharge rate. Additionally, battery lifespan must be considered. However, current batteries have relatively short lifespans.

[0117] During use, gas may be generated inside the battery cell, causing changes in the internal pressure and deformation of the pressure relief wall. Over time, the wall is prone to fatigue and damage, affecting the lifespan of the battery cell.

[0118] In view of this, embodiments of this application provide a battery cell, which includes a casing and a reinforcing portion. The casing includes a wall portion, and the wall portion has a weak portion. The weak portion is annular and is configured to be at least partially destroyed when the battery cell is depressurized. Along the thickness direction of the wall portion, the wall portion has a first surface, and the reinforcing portion is disposed on the first surface. The reinforcing portion has an annular structure, and the weak portion is disposed around the outside of the reinforcing portion.

[0119] A reinforcing section is provided on the first surface of the wall in the thickness direction. This reinforcing section strengthens the wall, improving its resistance to deformation and fatigue, reducing the risk of fatigue-induced failure, and thus extending its service life, which in turn improves the service life of the battery cell. Furthermore, the weak point is annular, and the reinforcing section is also annular, surrounding the outside of the reinforcing section. On one hand, the reinforcing effect of the reinforcing section on all locations of the weak point is relatively uniform, making it easier for the weak point to be completely destroyed during battery cell depressurization. This allows the area inside the weak point to easily detach from the wall, creating a larger opening through which the discharge material inside the battery cell can be quickly depressurized, improving the timeliness of battery cell depressurization. On the other hand, when the area inside the reinforcing section deforms under stress, the reinforcing section acts as a buffer, reducing the stress transmitted to the weak point, thereby reducing the risk of premature valve opening in the battery cell and improving the battery cell's lifespan and reliability.

[0120] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery cells and battery devices, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft.

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

[0122] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of this application. A battery device 100 is disposed inside the vehicle 1000, and the battery device 100 may be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000.

[0123] The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, for the power needs of the vehicle 1000 during startup, navigation and driving.

[0124] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0125] Please refer to Figure 2, which is an exploded view of a battery device 100 provided in some embodiments of this application. The battery device 100 may include a housing 10 and battery cells 20, with the housing 10 used to house the battery cells 20.

[0126] The housing 10 has an enclosed space inside for accommodating the battery cells 20. The housing 10 can have various structures. In some embodiments, the housing 10 may include a first housing body 11 and a second housing body 12, which are interlocked. The first housing body 11 and the second housing body 12 can have various shapes, such as cuboids or cylinders. The first housing body 11 can be a hollow structure open on one side, and the second housing body 12 can also be a hollow structure open on one side. The open side of the second housing body 12 interlocks with the open side of the first housing body 11, thus forming a housing 10 with an enclosed space. Alternatively, the first housing body 11 can be a hollow structure open on one side, and the second housing body 12 can be a plate-like structure, with the second housing body 12 interlocked with the open side of the first housing body 11, thus forming a housing 10 with an accommodating space.

[0127] In the battery device 100, there can be one or more battery cells 20. If there are multiple battery cells 20, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel. Alternatively, multiple battery cells 20 can be first connected in series, parallel, or in a mixed configuration to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the housing 10. Another option is that all battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the whole consisting of all battery cells 20 is housed within the housing 10.

[0128] In some embodiments, the battery device 100 may further include a busbar component, through which multiple battery cells 20 can be electrically connected to each other to achieve series, parallel, or mixed connection of the multiple battery cells 20. The busbar component may be a metallic conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0129] Please refer to Figures 3, 4, 5, 6, and 7. Figure 3 is an exploded view of a battery cell 20 provided in some embodiments of this application. Figure 4 is a structural schematic diagram of a wall portion 213 provided in some embodiments of this application. Figure 5 is a top view of a wall portion 213 provided in some embodiments of this application. Figure 6 is a cross-sectional view at position AA in Figure 5. Figure 7 is an enlarged view at position B in Figure 6. This application provides a battery cell 20, which includes a housing 21 and a reinforcing portion 22. The housing 21 includes a wall portion 213, which has a weak portion 2131. The weak portion 2131 is annular and is configured to be at least partially destroyed when the battery cell 20 is depressurized. Along the thickness direction of the wall portion 213, the wall portion 213 has a first surface 21311. The reinforcing portion 22 is disposed on the first surface 21311 and has an annular structure. The weak portion 2131 is disposed around the outside of the reinforcing portion 22.

[0130] Battery cell 20 refers to the smallest unit that makes up battery device 100.

[0131] The housing 21 includes a housing 211 and an end cap 212. The housing 211 has a receiving space with an opening at one end for accommodating the electrode assembly 23. The end cap 212 is connected to the housing 211 and closes the opening.

[0132] End cap 212 refers to a component that covers the opening of housing 211 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 212 can be adapted to the shape of housing 211 to fit it. Optionally, end cap 212 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 212 is less prone to deformation under pressure and impact, enabling battery cell 20 to have higher structural strength and improved safety performance. The material of end cap 212 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this.

[0133] The housing 211 is a component used to cooperate with the end cap 212 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 23, electrolyte, and other components. The housing 211 and the end cap 212 can be independent components. An opening can be provided on the housing 211, and the end cap 212 can be used to close the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 212 and the housing 211 can be integrated. Specifically, the end cap 212 and the housing 211 can form a common mating surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 211, the end cap 212 closes the housing 211. The housing 211 can have various shapes and sizes, such as cuboid or hexagonal prism. Specifically, the shape of the housing 211 can be determined according to the specific shape and size of the electrode assembly 23. The material of the housing 211 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, and plastic.

[0134] In some embodiments, the housing 211 may have an opening at only one end, and a corresponding end cap 212 may be provided. In other embodiments, the housing 211 may have openings at both ends, and two corresponding end caps 212 may be provided, with the two end caps 212 respectively closing the two opposite openings of the housing 211. In the embodiments shown in Figures 3 and 4, the housing 211 has an opening at only one end, and a corresponding end cap 212 may be provided.

[0135] Electrode terminals 24 may also be provided on the end cap 212 or the housing 211. These terminals are used for electrical connection to the tabs of the electrode assembly 23 to input or output electrical energy from the battery cell 20. The electrode terminals 24 and the tabs can be directly connected, for example, by direct welding. Alternatively, the electrode terminals 24 and the tabs can be indirectly connected, for example, through a current collector 25.

[0136] Electrode assembly 23 is the component in the battery cell 20 where electrochemical reactions occur. The housing 211 may contain one or more electrode assemblies 23. The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body of the electrode assembly 23, while the portions of the positive and negative electrode sheets without active material each constitute a tab. The positive and negative tabs may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery cell 20, the positive and negative active materials react with the electrolyte.

[0137] The wall portion 213 can be an end cap 212 of the outer casing 21, or it can be a wall of the housing 211 of the outer casing 21. In some embodiments, as shown in Figures 3 and 4, the wall portion 213 is an end cap 212. In other embodiments, the wall portion 213 can be a second bottom wall 2112 of the housing 211 opposite to the end cap 212. In still other embodiments, the wall portion 213 can also be a second side wall 2111 of the housing 211 adjacent to and connected to the end cap 212.

[0138] The wall portion 213 has a weak portion 2131, which serves a pressure-relieving function. When the internal pressure or temperature of the battery cell 20 reaches a predetermined value, the wall portion 213 can crack along the weak portion 2131 to release the internal pressure of the battery cell 20. In some embodiments, the strength of the wall portion 213 at the weak portion 2131 may be lower than the strength at other locations on the wall portion 213. This allows the weak portion 2131 to crack under the internal pressure when the internal pressure or temperature of the battery cell 20 reaches the predetermined value, thus releasing the internal pressure of the battery cell 20. In other embodiments, the melting point of the wall portion 213 at the weak portion 2131 may be lower than the melting point at other locations on the wall portion 213. This allows the weak portion 2131 to crack under high temperature when the internal pressure or temperature of the battery cell 20 reaches the predetermined value, thus releasing the internal pressure of the battery cell 20.

[0139] The weak part 2131 is ring-shaped, that is, the weak part 2131 is a closed structure extending along a closed trajectory. For example, the weak part 2131 can be ring-shaped, elliptical ring-shaped, racetrack-shaped, etc.

[0140] Please refer to Figures 6 and 7. The thickness direction of the wall portion 213 is the X direction shown in the figures.

[0141] The first surface 21311 can be the surface of the wall portion 213 facing the interior of the outer shell 21 along its thickness direction, or it can be the surface of the wall portion 213 facing away from the interior of the outer shell 21 along its thickness direction. The first surface 21311 can be the surface of the wall portion 213 closest to the interior of the outer shell 21 along its thickness direction, the surface of the wall portion 213 furthest from the interior of the outer shell 21 along its thickness direction, or the surface between the surface of the wall portion 213 closest to the interior of the outer shell 21 and the surface furthest from the interior of the outer shell 21 along its thickness direction. Taking the wall portion 213 as a flat plate structure as an example, the wall portion 213 has opposing inner and outer surfaces along its thickness direction. The inner surface of the wall portion 213 faces the interior of the outer shell 21 along its thickness direction. The first surface 21311 can be either the inner surface or the outer surface of the wall portion 213.

[0142] The reinforcing part 22 is the portion of the wall portion 213 that protrudes from the first surface 21311 and reinforces the wall portion 213. The reinforcing part 22 increases the rigidity of the wall portion 213 and enhances its resistance to deformation, thereby improving the overall resistance to deformation of the wall portion 213. The reinforcing part 22 is a ring-shaped structure. It can be a closed structure extending along a closed trajectory, such as a circular ring, an elliptical ring, or a racetrack shape. Alternatively, it can be a non-closed structure with gaps at both ends, such as a 180° arc shape or a 270° arc shape. Optionally, the shape of the reinforcing part 22 is the same as the shape of the weak part 2131. The reinforcing part 22 and the wall portion 213 can be integrally formed, for example, by stamping to form the reinforcing part 22 on the wall portion 213, making the reinforcing part 22 integrally formed with the wall portion 213; or the reinforcing part 22 and the wall portion 213 can be separately arranged and connected, such as by welding.

[0143] "The weak part 2131 is arranged around the outside of the reinforcing part 22" means that the weak part 2131 is arranged around the outside of the reinforcing part 22. In other words, the reinforcing part 22 is arranged in the area of ​​the wall part 213 located inside the weak part 2131.

[0144] The wall portion 213 has a reinforcing portion 22 on its first surface 21311 in the thickness direction. The reinforcing portion 22 strengthens the wall portion 213, improving its resistance to deformation and fatigue, reducing the risk of failure due to fatigue, and thus extending its service life, thereby improving the service life of the battery cell 20. Furthermore, the weak portion 2131 is annular, and the reinforcing portion 22 has a ring-shaped structure, with the weak portion 2131 surrounding the outside of the reinforcing portion 22. This ensures that the reinforcing effect of the reinforcing portion 22 on various locations of the weak portion 2131 is relatively uniform, making it easier for the weak portion 2131 to be completely destroyed when the battery cell 20 is depressurized. This allows the area of ​​the wall portion 213 located inside the weak portion 2131 to easily detach completely from the wall portion 213, creating a larger opening. This opening allows for rapid depressurization of the contents of the battery cell 20, improving the timeliness of depressurization. On the other hand, when the area of ​​the wall portion 213 located inside the reinforcing portion 22 is subjected to stress and deformation, the reinforcing portion 22 can play a buffering role, reducing the stress transmitted to the weak portion 2131, thereby reducing the risk of premature valve opening of the battery cell 20, which is beneficial to improving the life and reliability of the battery cell 20.

[0145] Please refer to Figures 3, 4, 5, 6 and 7. In some embodiments, the distance between the weak portion 2131 and the reinforcing portion 22 in the direction perpendicular to the thickness direction of the wall portion 213 is L, which satisfies: 1mm≤L≤4mm.

[0146] L represents the distance between the weak part 2131 and the reinforcing part 22 in a direction perpendicular to the thickness direction of the wall part 213. For example, when the wall part 213 is a disk structure, L represents the distance between the weak part 2131 and the reinforcing part 22 in the radial direction of the wall part 213.

[0147] The distance between the weak portion 2131 and the reinforcing portion 22 at different locations in the direction perpendicular to the thickness direction of the wall portion 213 can be the same. For example, both the weak portion 2131 and the reinforcing portion 22 are annular and are coaxially arranged. The distance between the weak portion 2131 and the reinforcing portion 22 at different locations in the direction perpendicular to the thickness direction of the wall portion 213 can also be different. In this case, the minimum distance between the weak portion 2131 and the reinforcing portion 22 in the direction perpendicular to the thickness direction of the wall portion 213 is greater than or equal to 1 mm, and the maximum distance between the weak portion 2131 and the reinforcing portion 22 in the direction perpendicular to the thickness direction of the wall portion 213 is less than or equal to 4 mm.

[0148] The distance between the weak part 2131 and the reinforcing part 22 in the direction perpendicular to the thickness direction of the wall part 213 can be: L = 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, etc.

[0149] When L ≥ 1 mm, the distance between the weak portion 2131 and the reinforcing portion 22 is relatively large in the direction perpendicular to the thickness of the wall portion 213. This makes it less likely that the reinforcing portion 22 will affect the weak portion 2131, thus reducing the risk of premature valve opening in the battery cell 20 and improving its lifespan and reliability. When L ≤ 4 mm, the distance between the weak portion 2131 and the reinforcing portion 22 is not too large in the direction perpendicular to the thickness of the wall portion 213. This results in a larger area of ​​the wall portion 213 inside the reinforcing portion 22, allowing the reinforcing portion 22 to provide better buffering, further reducing the risk of premature valve opening in the battery cell 20 and improving its lifespan and reliability. Therefore, when 1 mm ≤ L ≤ 4 mm, the battery cell 20 has a longer lifespan and higher reliability.

[0150] Optionally, 2mm≤L≤3mm.

[0151] The distance between the weak part 2131 and the reinforcing part 22 in the direction perpendicular to the thickness direction of the wall part 213 can be: L = 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, etc.

[0152] When L ≥ 2mm, the distance between the weak portion 2131 and the reinforcing portion 22 is greater in the direction perpendicular to the thickness of the wall portion 213. This makes it less likely that the reinforcing portion 22 will affect the weak portion 2131, thus reducing the risk of premature valve opening in the battery cell 20 and improving its lifespan and reliability. When L ≤ 3mm, the distance between the weak portion 2131 and the reinforcing portion 22 is not too large in the direction perpendicular to the thickness of the wall portion 213, resulting in a larger area of ​​the wall portion 213 inside the reinforcing portion 22. This allows the reinforcing portion 22 to provide better buffering, further reducing the risk of premature valve opening in the battery cell 20 and improving its lifespan and reliability. Therefore, when 2mm ≤ L ≤ 3mm, the battery cell 20 has a longer lifespan and higher reliability.

[0153] Referring to Figures 3, 4, 5, 6, and 7, in some embodiments, in the direction perpendicular to the thickness direction of the wall portion 213, the distance between the weak portion 2131 and the reinforcing portion 22 is less than the distance from the reinforcing portion 22 to the central axis of the weak portion 2131.

[0154] The central axis of the weak portion 2131 is parallel to the thickness direction of the wall portion 213 and passes through the geometric center of the weak portion 2131. When the weak portion 2131 is annular, its central axis is parallel to the thickness direction of the wall portion 213 and passes through the center of the annulus. When the weak portion 2131 is a rectangular ring, its central axis is parallel to the thickness direction of the wall portion 213 and passes through the intersection of the diagonals of the rectangle.

[0155] Please refer to Figure 6, in which the central axis of the weak part 2131 is marked with a dashed line.

[0156] "In the direction perpendicular to the thickness direction of the wall portion 213, the distance between the weak portion 2131 and the reinforcing portion 22 is less than the distance from the reinforcing portion 22 to the central axis of the weak portion 2131." In other words, in the direction perpendicular to the thickness direction of the wall portion 213, the maximum distance between the weak portion 2131 and the reinforcing portion 22 is less than the minimum distance from the reinforcing portion 22 to the central axis of the weak portion 2131. In other words, the reinforcing portion 22 is closer to the weak portion 2131 than the central axis of the weak portion 2131.

[0157] In the direction perpendicular to the thickness of the wall portion 213, the distance between the weak portion 2131 and the reinforcing portion 22 is less than the distance from the central axis of the reinforcing portion 22 to the weak portion 2131. This results in a larger area of ​​the wall portion 213 located inside the reinforcing portion 22, which allows the reinforcing portion 22 to play a better buffering role, reducing the risk of premature valve opening of the battery cell 20 and improving the lifespan and reliability of the battery cell 20.

[0158] Please refer to Figures 3, 4, 5, 6 and 7. In some embodiments, both the weak portion 2131 and the reinforcing portion 22 are annular, and the distance between the axis of the weak portion 2131 and the axis of the reinforcing portion 22 is less than or equal to 1 mm.

[0159] The statement "the distance between the axis of the weak part 2131 and the axis of the reinforcing part 22 is less than or equal to 1 mm" can also be understood as: the distance between the center line of the weak part 2131 and the center line of the reinforcing part 22 is less than or equal to 1 mm.

[0160] Both the weak portion 2131 and the reinforcing portion 22 are annular, and the distance between the axis of the weak portion 2131 and the axis of the reinforcing portion 22 is less than or equal to 1 mm. In this way, the weak portion 2131 and the reinforcing portion 22 are approximately coaxially arranged, so that the reinforcing effect of the reinforcing portion 22 on each position of the weak portion 2131 is more even. When the battery cell 20 is depressurized, the force on each position of the weak portion 2131 is more uniform, making it easier for the weak portion 2131 to be completely destroyed when the battery cell 20 is depressurized. This makes it easier for the area of ​​the wall portion 213 located inside the weak portion 2131 to completely detach from the wall portion 213, opening a larger opening. The discharge in the battery cell 20 can be quickly depressurized through this opening, which helps to improve the timeliness of depressurization of the battery cell 20.

[0161] Optionally, the axis of the weak part 2131 coincides with the axis of the reinforcing part 22.

[0162] Both the weak portion 2131 and the reinforcing portion 22 are annular, and the axis of the weak portion 2131 coincides with the axis of the reinforcing portion 22. In this way, the weak portion 2131 and the reinforcing portion 22 are coaxially arranged, so that the reinforcing effect of the reinforcing portion 22 on each position of the weak portion 2131 is most similar. When the battery cell 20 is depressurized, the force on each position of the weak portion 2131 is more uniform, making it easier for the weak portion 2131 to be completely destroyed when the battery cell 20 is depressurized. This makes it easier for the area of ​​the wall portion 213 located inside the weak portion 2131 to completely detach from the wall portion 213 and open a larger opening. The discharge in the battery cell 20 can be quickly depressurized through this opening, which helps to improve the timeliness of depressurization of the battery cell 20.

[0163] Referring to Figures 3, 4, 5, 6, and 7, in some embodiments, the wall portion 213 has a second surface 21312 disposed opposite to the first surface 21311, and the wall portion 213 is provided with a first groove 2133, which is annular. The first groove 2133 is recessed from the second surface 21312 in a direction close to the first surface 21311, and a reinforcing portion 22 protruding from the first surface 21311 is formed at a position of the wall portion 213 corresponding to the first groove 2133.

[0164] The second surface 21312 is the surface of the wall portion 213 opposite to the first surface 21311. The second surface 21312 can be the surface of the wall portion 213 facing the interior of the outer casing 21 along its thickness direction, or it can be the surface of the wall portion 213 facing away from the interior of the outer casing 21 along its thickness direction. When the first surface 21311 is the surface of the wall portion 213 facing the interior of the outer casing 21 along its thickness direction, the second surface 21312 is the surface of the wall portion 213 facing away from the interior of the outer casing 21 along its thickness direction.

[0165] The second surface 21312 can be the surface of the wall portion 213 closest to the interior of the outer shell 21 along its thickness direction, the surface of the wall portion 213 furthest from the interior of the outer shell 21 along its thickness direction, or the surface between the surface of the wall portion 213 closest to the interior of the outer shell 21 and the surface furthest from the interior of the outer shell 21 along its thickness direction. Taking the wall portion 213 as a flat plate structure as an example, the wall portion 213 has opposing inner and outer surfaces along its thickness direction, with the inner surface facing the interior of the outer shell 21 along its thickness direction. The second surface 21312 can be either the inner or outer surface of the wall portion 213. When the first surface 21311 is the inner surface of the wall portion 213, the second surface 21312 can be the outer surface of the wall portion 213.

[0166] The first groove 2133 is a groove provided on the second surface 21312, and the shape of the first groove 2133 is the same as the shape of the reinforcing part 22.

[0167] During molding, a first groove 2133 can be formed on the second surface 21312 by stamping, thereby forming a reinforcing part 22 protruding from the first surface 21311. The molding method of the reinforcing part 22 is simple. The setting of the first groove 2133 makes the wall part 213 form a recessed structure at the position where the reinforcing part 22 is set, so that the reinforcing part 22 has better resistance to deformation and improves the reinforcing effect of the reinforcing part 22 on the wall part 213.

[0168] Referring to Figures 3, 4, 5, 6, and 7, in some embodiments, along the thickness direction of the wall portion 213, the reinforcing portion 22 has a third surface 221 furthest from the first surface 21311. The distance between the bottom surface of the first groove 2133 and the third surface 221 is H1, and the distance between the first surface 21311 and the second surface 21312 is H2, satisfying: 0.5 ≤ H1 / H2 ≤ 1.5.

[0169] The third surface 221 is the surface of the reinforcing part 22 that is furthest from the first surface 21311 along the thickness direction of the wall part 213. Similarly, the third surface 221 is also the surface of the reinforcing part 22 that is furthest from the bottom surface of the first groove 2133 along the thickness direction of the wall part 213.

[0170] H1 represents the distance between the bottom surface of the first groove 2133 along the thickness direction of the wall 213 and the third surface 221. During measurement, multiple measurements can be taken and the average value can be used as H1.

[0171] H2 represents the distance between the first surface 21311 along the thickness direction of the wall 213 and the second surface 21312. During measurement, multiple measurements can be taken and the average value can be used as H2.

[0172] H1 / H2 represents the ratio of the distance between the bottom surface of the first groove 2133 along the thickness direction of the wall 213 and the distance between the third surface 221 and the distance between the first surface 21311 along the thickness direction of the wall 213 and the second surface 21312.

[0173] The ratio of the distance between the bottom surface of the first groove 2133 along the thickness direction of the wall 213 and the distance between the third surface 221 and the distance between the first surface 21311 along the thickness direction of the wall 213 and the second surface 21312 can be: H1 / H2 = 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, etc.

[0174] When H1 / H2 ≥ 0.5, the distance between the bottom surface of the first groove 2133 and the third surface 221 is relatively large along the thickness direction of the wall portion 213, resulting in a better strengthening and buffering effect for the reinforcing portion 22. When H1 / H2 ≤ 1.5, the distance between the bottom surface of the first groove 2133 and the third surface 221 is not too large along the thickness direction of the wall portion 213, which helps to reduce the occupancy of the reinforcing portion 22 on the internal space of the battery cell 20 or the battery device 100, and helps to improve the energy density of the battery cell 20 or the battery device 100. When 0.5 ≤ H1 / H2 ≤ 1.5, the distance between the bottom surface of the first groove 2133 and the third surface 221 is relatively close to the distance between the first surface 21311 and the second surface 21312 along the thickness direction of the wall portion 213, which facilitates the processing of the reinforcing portion 22 by stamping, and can take into account the strengthening effect, buffering effect and energy density of the battery cell 20.

[0175] Optionally, 0.8 ≤ H1 / H2 ≤ 1.2.

[0176] The ratio of the distance between the bottom surface of the first groove 2133 along the thickness direction of the wall 213 and the distance between the third surface 221 and the distance between the first surface 21311 along the thickness direction of the wall 213 and the second surface 21312 can be: H1 / H2 = 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, etc.

[0177] When H1 / H2 ≥ 0.8, the distance between the bottom surface of the first groove 2133 and the third surface 221 is larger along the thickness direction of the wall portion 213, resulting in better reinforcement and buffering effects for the reinforcing portion 22. When H1 / H2 ≤ 1.2, the distance between the bottom surface of the first groove 2133 and the third surface 221 is not too large along the thickness direction of the wall portion 213, which helps to reduce the occupancy of the reinforcing portion 22 on the internal space of the battery cell 20 or the battery device 100, thus improving the energy density of the battery cell 20 or the battery device 100. When 0.8 ≤ H1 / H2 ≤ 1.2, the distance between the bottom surface of the first groove 2133 and the third surface 221 is closer to the distance between the first surface 21311 and the second surface 21312 along the thickness direction of the wall portion 213, making it easier to process the reinforcing portion 22 by stamping, and better balancing the reinforcement effect, buffering effect, and energy density of the battery cell 20.

[0178] Referring to Figures 3, 4, 5, 6, and 7, in some embodiments, along the thickness direction of the wall portion 213, the height of the reinforcing portion 22 protruding from the first surface 21311 is H3, and the distance between the first surface 21311 and the second surface 21312 is H2, satisfying: 1 / 3 ≤ H3 / H2 ≤ 1.

[0179] H3 represents the height by which the reinforcing part 22 protrudes from the first surface 21311 along the thickness direction of the wall part 213, which is also the distance between the first surface 21311 and the third surface 221 along the thickness direction of the wall part 213. During measurement, multiple measurements can be taken and the average value can be used as H3.

[0180] H3 / H2 represents the ratio of the height at which the reinforcing part 22 protrudes from the first surface 21311 along the thickness direction of the wall part 213 to the distance between the first surface 21311 and the second surface 21312 along the thickness direction of the wall part 213.

[0181] The ratio of the height of the reinforcing part 22 protruding from the first surface 21311 along the thickness direction of the wall part 213 to the distance between the first surface 21311 and the second surface 21312 along the thickness direction of the wall part 213 can be: H3 / H2 = 1 / 3, 1 / 2, 2 / 3, 3 / 4, 4 / 5, 1, etc.

[0182] When H3 / H2 ≥ 1 / 3, the height of the reinforcing part 22 protruding from the first surface 21311 along the thickness direction of the wall 213 is relatively high, and the reinforcing part 22 has a good strengthening and buffering effect. When H3 / H2 ≤ 1, the height of the reinforcing part 22 protruding from the first surface 21311 along the thickness direction of the wall 213 is not too high. On the one hand, when the reinforcing part 22 is processed by stamping, it is not easy to cause the material to be overstretched and form a weak position. On the other hand, it is beneficial to reduce the occupation of the reinforcing part 22 on the internal space of the battery cell 20 or the battery device 100, which is beneficial to improving the energy density of the battery cell 20 or the battery device 100. When 1 / 3 ≤ H3 / H2 ≤ 1, the strengthening effect and buffering effect of the reinforcing part 22 and the energy density of the battery cell 20 can be balanced.

[0183] Referring to Figures 3, 4, 5, 6, and 7, in some embodiments, the wall portion 213 is provided with a second groove 2132, and the bottom wall of the second groove 2132 forms a weak portion 2131. Along the thickness direction of the wall portion 213, the bottom surface of the first groove 2133 is closer to the first surface 21311 than the bottom surface of the second groove 2132.

[0184] The second groove 2132 is a groove provided in the wall portion 213. The second groove 2132 can be provided on either the first surface 21311 or the second surface 21312. Taking the first surface 21311 as an example, the second groove 2132 is recessed from the first surface 21311 towards the second surface 21312, and the weak part 2131 is the portion between the bottom surface of the second groove 2132 and the second surface 21312.

[0185] The second groove 2132 can be formed by various methods, such as stamping or cold heading. Taking the stamping method as an example, the second groove 2132 can be stamped on the wall 213 along the thickness direction of the wall 213.

[0186] The second groove 2132 is formed by stamping or cold heading, which will cause the groove wall of the second groove 2132 to undergo cold work hardening (the grain arrangement changes, resulting in lattice distortion, which reduces the plasticity of the metal and increases the hardness of the material), thus enhancing its ability to resist external impact and making it less susceptible to damage from external impact.

[0187] It is understandable that, along the thickness direction of the wall portion 213, the bottom surface of the first groove 2133 is located between the bottom surface of the second groove 2132 and the first surface 21311.

[0188] The bottom surface of the first groove 2133 can be a plane or an arc surface. The bottom surface of the second groove 2132 can be a plane or an arc surface. As an example, in the embodiment shown in FIG7, the bottom surfaces of the first groove 2133 and the second groove 2132 are both planes and are parallel to the first surface 21311.

[0189] By making the bottom surface of the first groove 2133 closer to the first surface 21311 along the thickness direction of the wall 213 than the bottom surface of the second groove 2132, when the area of ​​the wall 213 located inside the reinforcement 22 is subjected to stress and deformation, the reinforcement 22 can play a better buffering role, reducing the stress transmitted to the weak part 2131, thereby reducing the risk of premature valve opening of the battery cell 20, which is beneficial to improving the life and reliability of the battery cell 20.

[0190] Referring to Figures 3, 4, 5, 6, and 7, in some embodiments, the reinforcing portion 22 has a first sidewall 223 and a first bottom wall 222. The first sidewall 223 surrounds the first bottom wall 222, and the first sidewall 223 and the first bottom wall 222 together define a first groove 2133. The thickness of the first sidewall 223 is H4, and the distance between the first surface 21311 and the second surface 21312 along the thickness direction of the wall portion 213 is H2, satisfying: H4 ≤ H2.

[0191] The first bottom wall 222 is a wall provided along the thickness direction of the wall portion 213 of the reinforcing part 22. Along the thickness direction of the wall portion 213, the first bottom wall 222 is positioned opposite the opening of the first groove 2133. The first side wall 223 is the portion of the reinforcing part 22 surrounding the first bottom wall 222. The extension trajectory of the first side wall 223 has the same shape as the first groove 2133. The thickness of the first side wall 223 can be uniform or non-uniform. If the thickness of the first side wall 223 is uniform, the maximum thickness of the first side wall 223 is equal to the minimum thickness of the first side wall 223, and both the maximum and minimum thickness of the first side wall 223 are H4.

[0192] In the embodiment shown in Figure 7, the thickness of the first sidewall 223 is non-uniform. Along the depth direction of the first groove 2133, the thickness of the first sidewall 223 gradually decreases. At this time, H4≤H2, that is, the maximum thickness of the first sidewall 223 is less than or equal to the distance between the first surface 21311 along the thickness direction of the wall portion 213 and the second surface 21312.

[0193] When H4≤H2, the thickness of the first sidewall 223 does not exceed the distance between the first surface 21311 and the second surface 21312, which simplifies the forming process. The reinforcing part 22 can be formed by stamping, and the forming method is simple.

[0194] Please refer to Figures 3, 4, 5, 6 and 7. In some embodiments, along the thickness direction of the wall portion 213, the thickness of the first bottom wall 222 is H1, and the distance between the first surface 21311 and the second surface 21312 is H2, satisfying: H1≤H2.

[0195] The thickness of the first bottom wall 222 along the thickness direction of the wall portion 213 is equal to the distance between the bottom surface of the first groove 2133 along the thickness direction of the wall portion 213 and the third surface 221.

[0196] The thickness of the first bottom wall 222 can be uniform or non-uniform. If the thickness of the first bottom wall 222 is uniform, the maximum thickness of the first bottom wall 222 is equal to the minimum thickness of the first bottom wall 222, and both the maximum thickness and the minimum thickness of the first bottom wall 222 are H1.

[0197] The thickness of the first bottom wall 222 can also be non-uniform. For example, along the width direction of the first groove 2133, the thickness of the first bottom wall 222 gradually increases from the middle to both ends. In this case, H1≤H2, that is, the maximum thickness of the first bottom wall 222 is less than or equal to the distance between the first surface 21311 along the thickness direction of the wall portion 213 and the second surface 21312.

[0198] When H1≤H2, the thickness of the first bottom wall 222 does not exceed the distance between the first surface 21311 and the second surface 21312, which simplifies the forming process. The reinforcing part 22 can be formed by stamping, and the forming method is simple.

[0199] Please refer to Figures 3, 4, 5, 6 and 7. In some embodiments, the wall portion 213 is provided with a second groove 2132, and the bottom wall of the second groove 2132 forms a weak portion 2131.

[0200] By creating a second groove 2132 on the wall portion 213, a weak portion 2131 is formed on the wall portion 213. When the battery cell 20 is depressurized, at least a portion of the wall portion 213 cracks along the second groove 2132. This method is simple, convenient, and low in cost.

[0201] Please refer to Figures 3, 4, 5, 6 and 7. In some embodiments, the second groove 2132 is disposed on the first surface 21311.

[0202] The reinforcing part 22 protrudes from the first surface 21311, and the second groove 2132 is disposed on the first surface 21311, that is, the reinforcing part 22 and the second groove 2132 are disposed on the same surface.

[0203] When the reinforcing part 22 and the second groove 2132 are processed by stamping, the wall part 213 is stamped from both sides of the wall part 213, so that the wall part 213 is not easily deformed to one side.

[0204] Please refer to Figures 3, 4, 5, 6 and 7. In some embodiments, the first surface 21311 faces the interior of the housing 21.

[0205] Since the reinforcing part 22 is disposed on the first surface 21311, which faces the interior of the outer casing 21, the reinforcing part 22 can utilize the internal space of the battery cell 20 without occupying the external space of the battery cell 20. In the embodiment where the second groove 2132 is disposed on the first surface 21311, the first surface 21311 faces the interior of the outer casing 21, such that the second groove 2132 faces the interior of the battery cell 20. The second groove 2132 is not exposed to the exterior of the battery cell 20, reducing the risk of oxidation of the area where the second groove 2132 is disposed on the wall portion 213 due to exposure to the exterior of the battery cell 20.

[0206] Please refer to Figures 3, 4, 5, 6, 7, and 8. Figure 8 is a cross-sectional view of a battery cell 20 provided in some embodiments of this application. In some embodiments, the battery cell 20 includes an electrode assembly 23, which is housed within a housing 21. The wall portion 213 includes a wall body 2135 and an abutment portion 2134, which surrounds the outer edge of the wall body 2135. Along the thickness direction of the wall portion 213, the abutment portion 2134 protrudes from the wall body 2135 in a direction close to the electrode assembly 23 and directly or indirectly abuts against the electrode assembly 23. The wall body 2135 includes a weak portion 2131.

[0207] The wall body 2135 and the abutment part 2134 can be integrally formed or they can be separately set and connected. The weak part 2131 can be formed by setting a groove on the wall body 2135, or by performing local heat treatment on the wall body 2135 to weaken the strength of the local area, thereby forming the weak part 2131.

[0208] The abutment portion 2134 can be an annular structure surrounding the outer edge of the wall body 2135. The annular structure can be a circular ring, a rectangular ring, etc. After the abutment portion 2134 directly or indirectly abuts against the electrode assembly 23, the abutment portion 2134 and the electrode assembly 23 can be electrically connected or insulated. If the abutment portion 2134 directly abuts against the electrode assembly 23, making direct contact between the abutment portion 2134 and the electrode assembly 23, for example, the abutment portion 2134 directly abuts against the tab at the end of the electrode assembly 23, to achieve an electrical connection between the wall portion 213 and the electrode assembly 23; if the abutment portion 2134 indirectly abuts against the electrode assembly 23, an intermediate component is provided between the abutment portion 2134 and the electrode assembly 23. This intermediate component can be an insulating component or a conductive component. Taking the current collector 25 as an example, the abutment 2134 can indirectly abut against the tab at the end of the electrode assembly 23 through the current collector 25 to achieve electrical connection between the wall 213 and the electrode assembly 23.

[0209] The abutment portion 2134 of the wall portion 213 directly or indirectly abuts against the electrode assembly 23. The abutment portion 2134 can restrict the electrode assembly 23 and reduce the risk of the electrode assembly 23 moving inside the housing 21.

[0210] Referring to Figures 3, 4, 5, 6, 7, and 8, in some embodiments, the outer casing 21 includes a second sidewall 2111 surrounding the wall portion 213. Along the thickness direction of the wall portion 213, the wall portion 213 is located at one end of the second sidewall 2111. A first flow channel 2113 is formed between the electrode assembly 23 and the second sidewall 2111. The abutment portion 2134 and the wall body 2135 together define a flow space 2137. The abutment portion 2134 is provided with a second flow channel 2138, which connects the flow space 2137 and the first flow channel 2113.

[0211] In embodiments where the housing 211 has an opening at only one end, the end cap 212 can serve as the wall portion 213, and the second side wall 2111 can be part of the housing 211; alternatively, the second bottom wall 2112 opposite to the end cap 212 can serve as the wall portion 213, and the second side wall 2111 and the wall portion 213 can be integrally formed to constitute the housing 211. In embodiments where both opposite ends of the housing 211 have openings, at least one of the two end caps 212 can serve as the wall portion 213, and the second side wall 2111 can be the housing 211.

[0212] The second sidewall 2111 can be cylindrical, making the battery cell 20 a cylindrical battery cell; the second sidewall 2111 can also be cuboid, making the battery cell 20 a prismatic battery cell or a blade battery cell. The second sidewall 2111 and the wall portion 213 can be integrally formed, constituting the housing 211, with the end of the second sidewall 2111 away from the wall portion 213 forming an opening in the housing 211; alternatively, the second sidewall 2111 and the wall portion 213 can be separate components, with the wall portion 213 serving as an end cap 212, and the end of the second sidewall 2111 near the wall portion 213 forming an opening in the housing 211. In embodiments where the second sidewall 2111 and the wall portion 213 are separate components, the wall portion 213 and the second sidewall 2111 can be connected by welding, bonding, or roll sealing.

[0213] The first flow channel 2113 can be the gap formed between the outer peripheral surface of the main body and the outer peripheral surface of the electrode tab and the inner peripheral surface of the second sidewall 2111. Alternatively, if the outer periphery of the main body is covered with an insulating film, the first flow channel 2113 can be the gap formed between the outer peripheral surface of the insulating film and the outer peripheral surface of the electrode tab and the inner peripheral surface of the second sidewall 2111. The inner peripheral surface of the second sidewall 2111 is the surface of the second sidewall 2111 facing the electrode assembly 23, and the inner peripheral surface can extend circumferentially around the opening of the outer casing 21. It can be understood that if the second sidewall 2111 is cylindrical, its inner peripheral surface is cylindrical; if the second sidewall 2111 is cuboid, its inner peripheral surface is cuboid.

[0214] The flow guiding space 2137, defined by the wall body 2135 and the abutment portion 2134, corresponds to the region of the wall portion 213 located inside the weak portion 2131. After the weak portion 2131 cracks, the discharge within the flow guiding space 2137 can be discharged to the outside of the battery cell 20 through the region of the wall portion 213 located inside the weak portion 2131. The flow guiding space 2137 has an opening at the end of the abutment portion 2134 near the electrode assembly 23. After the abutment portion 2134 directly or indirectly abuts against the electrode assembly 23, the opening is covered. It can be understood that if the abutment portion 2134 directly abuts against the electrode assembly 23, the opening of the flow guiding space 2137 is covered by the electrode assembly 23; if the abutment portion 2134 indirectly abuts against the electrode assembly 23 through an intermediate member, the opening of the flow guiding space 2137 is covered by the intermediate member.

[0215] There may be one or more second guide channels 2138 on the abutment part 2134. If there are multiple second guide channels 2138, the multiple guide channels may be evenly distributed along the circumference of the abutment part 2134 or non-uniformly distributed along the circumference of the abutment part 2134.

[0216] The second flow channel 2138 can be a through hole provided in the abutment part 2134, or it can be a notch or groove.

[0217] Because the abutment part 2134 is provided with a second flow channel 2138, which connects the flow space 2137 and the first flow channel 2113, when the battery cell 20 experiences thermal runaway, the emissions generated by the electrode assembly 23 flow into the first flow channel 2113. The emissions can then flow rapidly into the flow space 2137 through the second flow channel 2138 on the abutment part 2134, causing the air pressure in the flow space 2137 to rise rapidly and reach the burst pressure quickly. This allows the weak part 2131 to be destroyed in time, shortening the time from the thermal runaway of the battery cell 20 to the start of depressurization of the battery cell 20, reducing the risk of the battery cell 20 exploding or catching fire, and effectively improving the reliability of the battery cell 20.

[0218] Optionally, the abutment portion 2134 includes a body portion 21341 and a plurality of protrusions 21342. The body portion 21341 is disposed around the outer edge of the wall body 2135 and protrudes from the wall body 2135 in a direction close to the electrode assembly 23. The body portion 21341 has a fifth surface 21354 facing the electrode assembly 23. The protrusions 21342 are disposed on the fifth surface 21354 and directly abut against the current collecting member 25. Along the circumference of the abutment portion 2134, a second flow channel 2138 is formed between two adjacent protrusions 21342.

[0219] Please refer to Figures 3, 4, 5, 6, 7 and 8. In some embodiments, the wall portion 213 further includes an edge portion 2136, which is disposed around the outer edge of the abutment portion 2134 and abuts against one end of the second sidewall 2111 in the direction of the wall portion 213 toward the electrode assembly 23.

[0220] The edge portion 2136 is an annular structure surrounding the outer edge of the abutment portion 2134. The outer edge of the edge portion 2136 is the outer edge of the wall portion 213.

[0221] As an example, the second sidewall 2111 is part of the housing 211, the housing 211 has an opening at only one end, the edge portion 2136 abuts against the end of the housing 211 with the opening in the direction of the wall portion 213 pointing toward the electrode assembly 23, and the edge portion 2136 is welded to the second sidewall 2111.

[0222] The edge portion 2136 abuts against the second sidewall 2111 to limit the wall portion 213 and restrict the wall portion 213 from moving in the direction close to the electrode assembly 23.

[0223] Referring to Figures 3, 4, 5, 6, 7, and 8, in some embodiments, along the thickness direction of the wall portion 213, the wall body 2135 has a fourth surface 21353 and a fifth surface 21354 disposed opposite to each other. The fourth surface 21353 faces the electrode assembly 23. The wall body 2135 is provided with a recess 21351, which is recessed from the fifth surface 21354 in a direction close to the fourth surface 21353. A protrusion 21352 is formed on the wall body 2135 at a position corresponding to the recess 21351, protruding from the fourth surface 21353. The surface of the protrusion 21352 facing the electrode assembly 23 is the first surface 21311. Along the thickness direction of the wall portion 213, the orthographic projection of the weak portion 2131 is located within the recess 21351.

[0224] The fourth surface 21353 faces the interior of the outer casing 21. The fourth surface 21353 and the first surface 21311 can be the same surface of the wall body 2135. In the embodiment shown in FIG. 7, the fourth surface 21353 and the first surface 21311 can also be two surfaces that are separated by a distance in the thickness direction of the wall portion 213. The fifth surface 21354 is the surface of the wall body 2135 that faces away from the interior of the outer casing 21 along the thickness direction of the wall portion 213. The fifth surface 21354 can be an annular surface surrounding the outer side of the recess 21351.

[0225] The weak part 2131 is projected along the thickness direction of the wall part 213 into the recess 21351. The weak part 2131 is the part between the bottom surface of the groove of the second groove 2132 and the bottom surface of the recess 21351.

[0226] The recess 21351 creates a certain distance between the area of ​​the wall portion 213 located inside the weak portion 2131 and the fifth surface 21354. When the fifth surface 21354 contacts the external component, it can reduce the impact of the external component on the area of ​​the wall portion 213 located inside the weak portion 2131. This allows the area of ​​the wall portion 213 located inside the weak portion 2131 to open outward when the battery cell 20 is depressurized, reducing the risk that the area of ​​the wall portion 213 located inside the weak portion 2131 will not be able to open properly due to obstruction by the external component.

[0227] Please refer to Figures 3, 4, 5, 6, 7 and 8. In some embodiments, the housing 21 includes a housing 211 and an end cap 212. The housing 211 has an opening, and the end cap 212 closes the opening. The end cap 212 is a wall portion 213.

[0228] The end cap 212 is a wall 213, which makes the end cap 212 have a weak part 2131, reducing the molding difficulty or installation difficulty of the weak part 2131.

[0229] Please refer to Figures 3, 4, 5, 6, 7 and 8. In some embodiments, the battery cell 20 is a cylindrical battery cell, and the thickness direction of the wall portion 213 is parallel to the axial direction of the cylindrical battery cell.

[0230] This application embodiment also provides a battery device 100, which includes the aforementioned battery cell 20.

[0231] In some embodiments, along the thickness direction of the wall portion 213, the wall portion 213 has a fourth surface 21353 and a fifth surface 21354 disposed opposite to each other, the fourth surface 21353 facing the interior of the outer casing 21. The wall portion 213 is provided with a recess 21351, the recess 21351 being recessed from the fifth surface 21354 in a direction close to the fourth surface 21353, and a protrusion 21352 protruding from the fourth surface 21353 is formed at a position of the wall portion 213 corresponding to the recess 21351. The surface of the protrusion 21352 facing the interior of the outer casing 21 is the first surface 21311. Along the thickness direction of the wall portion 213, the orthographic projection of the weak portion 2131 is located within the recess 21351. The battery device 100 also includes a housing 10, within which a battery cell 20 is housed. The battery cell 20 is fixed to the housing 10 by an adhesive layer, the adhesive layer being at least partially housed within the recess 21351.

[0232] The adhesive layer is the structure formed after the adhesive material has cured; the adhesive material can be a structural adhesive.

[0233] By at least partially accommodating the adhesive layer within the recess 21351, the space occupied by the adhesive layer inside the housing 10 can be reduced, thereby increasing the energy density of the battery device 100. Furthermore, since the adhesive layer is at least partially accommodated within the recess 21351, the contact area between the adhesive layer and the wall 213 is larger, which can improve the bonding strength between the battery cell 20 and the housing 10.

[0234] In some embodiments, the wall portion 213 is provided with a first groove 2133, which is annular. The first groove 2133 is recessed from the bottom surface of the recess 21351 in a direction close to the first surface 21311, and a reinforcing portion 22 protruding from the first surface 21311 is formed at a position of the wall portion 213 corresponding to the first groove 2133.

[0235] During molding, a first groove 2133 can be formed on the bottom surface of the recess 21351 by stamping, thereby forming a reinforcing part 22 protruding from the first surface 21311. The molding method of the reinforcing part 22 is simple. The setting of the first groove 2133 makes the wall part 213 form a recessed structure at the position where the reinforcing part 22 is set, so that the reinforcing part 22 has better resistance to deformation and improves the reinforcing effect of the reinforcing part 22 on the wall part 213.

[0236] In some embodiments, a portion of the adhesive layer is accommodated within the first groove 2133.

[0237] Optionally, a portion of the adhesive layer is accommodated in the recess 21351, and another portion of the adhesive layer is accommodated in the first groove 2133.

[0238] By accommodating a portion of the adhesive layer within the first groove 2133, the space occupied by the adhesive layer inside the housing 10 can be reduced, thereby increasing the energy density of the battery device 100. Furthermore, since the adhesive layer is at least partially accommodated within the first groove 2133, the contact area between the adhesive layer and the wall 213 is increased, thereby enhancing the bonding strength between the battery cell 20 and the housing 10.

[0239] In other embodiments, the first groove 2133 does not contain an adhesive layer.

[0240] The first groove 2133 does not contain an adhesive layer, and the adhesive layer does not easily prevent the weak part 2131 from cracking, so that the battery cell 20 can release pressure smoothly, which is beneficial to improving the timeliness of pressure release of the battery cell 20.

[0241] This application embodiment also provides an electrical device, which includes the aforementioned battery cell 20, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0242] This application provides a battery cell 20, which includes a housing 21 and a reinforcing portion 22. The housing 21 includes a wall 213, and the wall 213 has a weak portion 2131. The weak portion 2131 is annular and is configured to be at least partially destroyed when the battery cell 20 is depressurized. Along the thickness direction of the wall 213, the wall 213 has a first surface 21311, and the reinforcing portion 22 is disposed on the first surface 21311. The reinforcing portion 22 is annular, and the weak portion 2131 is disposed around the outside of the reinforcing portion 22. The reinforcing portion 22 is disposed on the first surface 21311 of the wall 213 in the thickness direction, which strengthens the wall 213, improves its resistance to deformation, improves its fatigue resistance, reduces the risk of the wall 213 being destroyed due to fatigue, and gives the wall 213 a longer service life, thereby improving the service life of the battery cell 20. Furthermore, both the weak portion 2131 and the reinforcing portion 22 are annular. The weak portion 2131 is arranged around the outside of the reinforcing portion 22. On the one hand, the reinforcing effect of the reinforcing portion 22 on various positions of the weak portion 2131 is relatively similar, making it easier for the weak portion 2131 to be completely destroyed when the battery cell 20 is depressurized. This allows the area of ​​the wall portion 213 located inside the weak portion 2131 to easily detach completely from the wall portion 213, opening a larger opening. The discharge inside the battery cell 20 can be quickly depressurized through this opening, which helps improve the timeliness of depressurization of the battery cell 20. On the other hand, when the area of ​​the wall portion 213 located inside the reinforcing portion 22 is deformed by force, the reinforcing portion 22 can act as a buffer, reducing the stress transmitted to the weak portion 2131, thereby reducing the risk of premature valve opening of the battery cell 20 and helping to improve the life and reliability of the battery cell 20.

[0243] Both the weak portion 2131 and the reinforcing portion 22 are annular, with the axis of the weak portion 2131 coinciding with the axis of the reinforcing portion 22. This coaxial arrangement of the weak portion 2131 and the reinforcing portion 22 ensures that the reinforcing effect of the reinforcing portion 22 on various locations of the weak portion 2131 is most even. When the battery cell 20 is depressurized, the force on various locations of the weak portion 2131 is more uniform, making it easier for the weak portion 2131 to be completely destroyed during depressurization. This also makes it easier for the area of ​​the wall portion 213 located inside the weak portion 2131 to completely detach from the wall portion 213, opening a larger opening. The discharge material inside the battery cell 20 can then be quickly depressurized through this opening, improving the timeliness of depressurization of the battery cell 20.

[0244] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, wherein, include: The housing includes a wall portion having a weak portion, the weak portion being annular, the weak portion being configured to be at least partially destroyed when the battery cell is depressurized, and the wall portion having a first surface along the thickness direction of the wall portion; A reinforcing portion is disposed on the first surface, the reinforcing portion having a ring-shaped structure, and a weak portion is disposed around the outside of the reinforcing portion.

2. The battery cell of claim 1, wherein, In the direction perpendicular to the thickness direction of the wall portion, the distance between the weak portion and the reinforcing portion is L, which satisfies: 1mm≤L≤4mm.

3. The battery cell of claim 2, wherein, 2mm≤L≤3mm.

4. The battery cell of any one of claims 1-3, wherein, In a direction perpendicular to the thickness direction of the wall portion, the distance between the weak portion and the reinforcing portion is less than the distance from the reinforcing portion to the central axis of the weak portion.

5. The battery cell of any one of claims 1-4, wherein, Both the weak part and the reinforcing part are annular, and the distance between the axis of the weak part and the axis of the reinforcing part is less than or equal to 1 mm.

6. The battery cell of claim 5, wherein, The axis of the weak part and the axis of the strengthening part coincide.

7. The battery cell of any one of claims 1-6, wherein, The wall portion has a second surface disposed opposite to the first surface, and the wall portion is provided with a first groove, which is annular. The first groove is recessed from the second surface in a direction close to the first surface, and a reinforcing portion protruding from the first surface is formed at a position of the wall portion corresponding to the first groove.

8. The battery cell of claim 7, wherein, Along the thickness direction of the wall portion, the reinforcing portion has a third surface furthest from the first surface, the distance between the bottom surface of the first groove and the third surface is H1, and the distance between the first surface and the second surface is H2, satisfying: 0.5≤H1 / H2≤1.

5.

9. The battery cell of claim 8, wherein, 0.8≤H1 / H2≤1.

2.

10. The battery cell according to any one of claims 7-9, wherein, Along the thickness direction of the wall portion, the height of the reinforcing portion protruding from the first surface is H3, and the distance between the first surface and the second surface is H2, satisfying: 1 / 3≤H3 / H2≤1.

11. The battery cell according to any one of claims 7-10, wherein, The wall portion is provided with a second groove, and the bottom wall of the second groove forms the weak portion; Along the thickness direction of the wall portion, the bottom surface of the first groove is closer to the first surface than the bottom surface of the second groove.

12. The battery cell according to any one of claims 7-11, wherein, The reinforcing part has a first sidewall and a first bottom wall, the first sidewall surrounds the first bottom wall, and the first sidewall and the first bottom wall together define the first groove. The thickness of the first sidewall is H4, and the distance between the first surface and the second surface along the thickness direction of the wall is H2, satisfying: H4≤H2.

13. The battery cell according to claim 12, wherein, Along the thickness direction of the wall portion, the thickness of the first bottom wall is H1, and the distance between the first surface and the second surface is H2, satisfying: H1≤H2.

14. The battery cell according to any one of claims 1-13, wherein, The wall portion is provided with a second groove, and the bottom wall of the second groove forms the weak portion.

15. The battery cell according to claim 14, wherein, The second groove is disposed on the first surface.

16. The battery cell according to any one of claims 1-15, wherein, The first surface faces the interior of the housing.

17. The battery cell according to any one of claims 1-16, wherein, The battery cell includes an electrode assembly, which is housed within the housing; The wall portion includes a wall body and an abutment portion. The abutment portion is disposed around the outer edge of the wall body. Along the thickness direction of the wall portion, the abutment portion protrudes from the wall body in a direction close to the electrode assembly and directly or indirectly abuts against the electrode assembly. The wall body includes the weak portion.

18. The battery cell according to claim 17, wherein, The outer casing includes a second sidewall surrounding the wall portion, and the wall portion is located at one end of the second sidewall along the thickness direction of the wall portion. A first flow channel is formed between the electrode assembly and the second sidewall. The abutting part and the wall body together define a flow space. The abutting part is provided with a second flow channel, which connects the flow space and the first flow channel.

19. The battery cell according to claim 18, wherein, The wall portion further includes an edge portion, which is disposed around the outer edge of the abutment portion and abuts against one end of the second sidewall in the direction of the wall portion toward the electrode assembly.

20. The battery cell according to any one of claims 17-19, wherein, Along the thickness direction of the wall portion, the wall body has a fourth surface and a fifth surface disposed opposite to each other. The fourth surface faces the electrode assembly. The wall body is provided with a recess. The recess is recessed from the fifth surface in a direction close to the fourth surface. A protrusion protruding from the fourth surface is formed at a position on the wall body corresponding to the recess. The surface of the protrusion facing the electrode assembly is the first surface. Along the thickness direction of the wall portion, the orthographic projection of the weak portion lies within the recess.

21. The battery cell according to any one of claims 1-20, wherein, The housing includes a shell and an end cap, the shell having an opening, the end cap closing the opening, and the end cap being the wall portion.

22. The battery cell according to any one of claims 1-21, wherein, The battery cell is a cylindrical battery cell, and the thickness direction of the wall portion is parallel to the axial direction of the cylindrical battery cell.

23. A battery device, wherein, Includes the battery cell according to any one of claims 1-22.

24. The battery device according to claim 23, wherein, Along the thickness direction of the wall portion, the wall portion has a fourth surface and a fifth surface disposed opposite to each other. The fourth surface faces the interior of the outer shell. The wall portion is provided with a recess. The recess is recessed from the fifth surface in a direction close to the fourth surface. A protrusion is formed on the wall portion at a position corresponding to the recess, protruding from the fourth surface. The surface of the protrusion facing the interior of the outer shell is the first surface. Along the thickness direction of the wall portion, the orthographic projection of the weak portion is located in the recess. The battery device further includes a housing, in which the individual battery cells are housed. The individual battery cells are fixed to the housing by an adhesive layer, which is at least partially housed within the recess.

25. The battery device according to claim 24, wherein, The wall portion is provided with a first groove, which is annular. The first groove is recessed from the bottom surface of the recess along the direction close to the first surface, and a reinforcing portion protruding from the first surface is formed at the position of the wall portion corresponding to the first groove.

26. The battery device according to claim 25, wherein, A portion of the adhesive layer is contained within the first groove.

27. The battery device according to claim 25, wherein, The first groove does not contain the adhesive layer.

28. An electrical appliance, wherein, Includes a battery cell according to any one of claims 1-22, the battery cell being used to provide electrical energy to the electrical device.

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