Battery cell, battery apparatus, and electric apparatus

Abstract

The present application provides a battery cell, a battery apparatus, and an electric apparatus. A housing of the battery cell comprises a first wall and a second wall disposed opposite to each other in a first direction; the first wall comprises a body portion, a connecting portion, and a first transition portion, the first transition portion connecting the body portion and the connecting portion; in the first direction, the connecting portion has a first surface and a second surface opposite to each other, the first surface being a surface of the first wall closest to the second wall, the body portion having a third surface and a fourth surface opposite to each other, the third surface being a surface of the first wall farthest away from the second wall, the fourth surface being farther away from the second wall than the first surface, and a distance between the first surface and the second surface being smaller than a distance between the third surface and the fourth surface. A smaller distance between a first surface and a second surface helps to reduce a maximum dimension of a first wall in a first direction, which reduces space taken up by the first wall inside a housing, thereby improving space utilization within the housing, and increasing battery cell energy density.

Description

Battery cells, battery packs and electrical devices

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese patent application 202510377953.8, filed on March 27, 2025, entitled “Battery Cell, Battery Device and Power Consumption Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, and more specifically, to a battery cell, a battery device, and an electrical device. Background Technology

[0004] Batteries are widely used in new energy vehicles, electronic devices, and other fields. As the demand for batteries increases, higher requirements are being placed on their energy density. Summary of the Invention

[0005] This application provides a battery cell, a battery device, and an electrical device that can improve the energy density of the battery cell.

[0006] In a first aspect, embodiments of this application provide a battery cell, the battery cell including a housing and an electrode assembly; the housing includes a first wall and a second wall disposed opposite to each other along a first direction; the electrode assembly is housed within the housing and located between the first wall and the second wall; the first wall includes a connected body portion, a connecting portion and a first transition portion, the first transition portion connecting the body portion and the connecting portion, the connecting portion having a first surface and a second surface disposed opposite to each other along the first direction, the first surface being the surface of the first wall closest to the second wall, the body portion having a third surface and a fourth surface disposed opposite to each other, the third surface being the surface of the first wall furthest from the second wall, the fourth surface being further away from the second wall than the first surface, and the distance between the first surface and the second surface being less than the distance between the third surface and the fourth surface.

[0007] In the above technical solution, along the first direction, the connecting portion has a first surface and a second surface opposite to each other. The first surface is the surface of the first wall closest to the second wall. Therefore, the connecting portion can limit the electrode assembly in the first direction, reducing or preventing the electrode assembly from shifting in the first direction, thereby improving the reliability of the battery cell. The body portion has a third surface and a fourth surface opposite to each other. The third surface is the surface of the first wall furthest from the second wall. The distance between the first surface and the third surface is the maximum dimension of the first wall in the first direction. By making the distance between the first surface and the second surface smaller than the distance between the third surface and the fourth surface, the distance between the first surface and the second surface is smaller, which helps to reduce the distance between the first surface and the third surface in the first direction. This helps to reduce the maximum dimension of the first wall in the first direction, thereby reducing the space occupied by the first wall in the internal space of the casing in the first direction, improving the utilization rate of the internal space of the casing, and thus helping to improve the energy density of the battery cell.

[0008] In some embodiments of the first aspect of this application, along the first direction, the distance between the first surface and the third surface is T, and the distance between the third surface and the fourth surface is T1, where 0.35 ≤ T1 / T ≤ 0.45.

[0009] In the above technical solution, with a fixed distance between the third and fourth surfaces, a larger T1 / T results in a smaller T, leading to a smaller overall size of the first wall in the first direction. Therefore, T1 / T ≥ 0.35, resulting in a smaller overall size of the first wall in the first direction. This reduces the space occupied by the first wall within the internal space of the casing in the first direction, improving the utilization rate of the internal space and thus increasing the energy density of the battery cell. With a fixed distance between the third and fourth surfaces, a smaller T1 / T results in a larger T, leading to a larger size of the first wall in the first direction. Therefore, T1 / T ≤ 0.45, resulting in a larger ratio between the distance between the first and fourth surfaces in the first direction and the distance between the first and third surfaces in the first direction. This allows for a larger protrusion of the connecting part from the fourth surface in the first direction, facilitating the limiting of the electrode assembly in the first direction, reducing or preventing the electrode assembly from shifting in the first direction, thereby improving the reliability of the battery cell. Therefore, 0.35 ≤ T1 / T ≤ 0.45 improves both the reliability and energy density of the battery cell.

[0010] In some embodiments of the first aspect of this application, along the first direction, the distance between the first surface and the third surface is T, and the distance between the first surface and the second surface is T2, where 0.32≤T2 / T≤0.4.

[0011] In the above technical solution, by T2 / T≥0.32, the distance between the first surface and the second surface 21122 can be increased, so that the connection part has better strength, thereby improving the strength of the first wall. Alternatively, the distance between the first surface and the third surface can be reduced, thereby reducing the overall size of the first wall in the first direction and reducing the space occupied by the first wall in the internal space of the shell in the first direction, which is beneficial to improving the utilization rate of the internal space of the shell and thus improving the energy density of the battery cell. By T2 / T≤0.42, the distance between the first surface and the second surface can be reduced, thereby reducing the space occupied by the first wall in the internal space of the shell in the first direction, which is beneficial to improving the utilization rate of the internal space of the shell. Therefore, 0.32≤T2 / T≤0.4 can improve both the reliability and the energy density of the battery cell.

[0012] In some embodiments of the first aspect of this application, the distance between the first surface and the second surface is T2, the distance between the third surface and the fourth surface is T1, and 0.65≤T2 / T1≤0.85.

[0013] In the above technical solution, by having T2 / T1≥0.65, the difference between the distance between the first and second surfaces and the distance between the third and fourth surfaces can be reduced, resulting in higher strength of the connection part and thus better strength of the first wall, thereby improving the reliability of the battery cell. By having T2 / T1≤0.85, the distance between the first and second surfaces is sufficiently small, thereby reducing the overall size of the first wall in the first direction and reducing the space occupied by the first wall in the internal space of the casing in the first direction, which is beneficial to improving the utilization rate of the internal space of the casing and thus improving the energy density of the battery cell. Therefore, 0.65≤T2 / T1≤0.85 enables the battery cell to have higher reliability and energy density.

[0014] In some embodiments of the first aspect of this application, the distance between the first surface and the third surface along the first direction is T, where 1.1 mm ≤ T ≤ 1.6 mm.

[0015] In the above technical solution, by ensuring the distance between the first and third surfaces in the first direction is greater than or equal to 1.1 mm, the first wall has better strength, thereby giving the outer casing higher strength and improving the reliability of the battery cell. By ensuring the distance between the first and third surfaces in the first direction is less than or equal to 1.6 mm, the maximum size of the first wall in the first direction is reduced, thus reducing the space occupied by the first wall in the internal space of the casing in the first direction, which helps to improve the utilization rate of the internal space of the casing and thus helps to improve the energy density of the battery cell. Therefore, 1.1 mm ≤ T ≤ 1.6 mm ensures both good reliability and good energy density for the battery cell.

[0016] In some embodiments of the first aspect of this application, the distance between the third surface and the fourth surface along the first direction is T1, where 0.35mm ≤ T1 ≤ 0.8mm; alternatively, 0.55mm ≤ T1 ≤ 0.65mm.

[0017] In the above technical solution, by ensuring that the distance between the third and fourth surfaces along the first direction is greater than or equal to 0.35 mm, the body portion has better strength, resulting in better strength of the first wall and thus higher strength of the outer casing, improving the reliability of the battery cell. By ensuring that the distance between the third and fourth surfaces along the first direction is less than or equal to 0.8 mm, the maximum size of the body portion in the first direction is reduced, thereby reducing the space occupied by the body portion in the internal space of the outer casing in the first direction. This, in turn, reduces the space occupied by the first wall in the internal space of the outer casing, improving the utilization rate of the internal space of the outer casing and thus increasing the energy density of the battery cell. Therefore, 0.35 mm ≤ T1 ≤ 0.8 mm ensures both good reliability and good energy density for the battery cell. By ensuring that the distance between the third and fourth surfaces along the first direction is greater than or equal to 0.55 mm, the body portion has better strength, resulting in better strength of the first wall and thus higher strength of the outer casing, further improving the reliability of the battery cell. By ensuring that the distance between the third and fourth surfaces along the first direction is less than or equal to 0.65 mm, it is beneficial to further reduce the maximum size of the main body in the first direction, thereby further reducing the space occupied by the main body in the internal space of the casing in the first direction. This also helps to reduce the space occupied by the first wall in the internal space of the casing in the first direction, further improving the utilization rate of the internal space of the casing, and thus further improving the energy density of the battery cell. Therefore, 0.55 mm ≤ T1 ≤ 0.65 mm not only gives the battery cell better reliability but also better energy density.

[0018] In some embodiments of the first aspect of this application, the distance between the first surface and the second surface along the first direction is T2, where 0.25mm≤T2≤0.7mm; alternatively, 0.35mm≤T2≤0.6mm.

[0019] In the above technical solution, by ensuring that the distance between the first and second surfaces along the first direction is greater than or equal to 0.25 mm, the connecting part has better strength, which in turn gives the first wall better strength, resulting in higher strength of the outer casing and improved reliability of the battery cell. The larger distance between the first and second surfaces also facilitates connection between the connecting part and other structures (current collectors). By ensuring that the distance between the first and second surfaces along the first direction is less than or equal to 0.7 mm, the maximum size of the connecting part in the first direction is reduced, thereby reducing the space occupied by the connecting part in the first direction of the outer casing. This also reduces the space occupied by the first wall in the first direction of the outer casing, thus improving the utilization rate of the internal space of the outer casing and increasing the energy density of the battery cell. Therefore, 0.25 mm ≤ T2 ≤ 0.7 mm ensures both good reliability and good energy density for the battery cell. By ensuring that the distance between the first and second surfaces along the first direction is greater than or equal to 0.35 mm, the connecting part has better strength, which in turn gives the first wall better strength, resulting in higher strength of the outer casing and further improving the reliability of the battery cell. By ensuring that the distance between the first and second surfaces along the first direction is less than or equal to 0.6 mm, it is beneficial to further reduce the maximum size of the connecting portion in the first direction, further reduce the space occupied by the connecting portion in the internal space of the housing in the first direction, and consequently reduce the space occupied by the first wall in the internal space of the housing in the first direction. This improves the utilization rate of the internal space of the housing and thus helps to further increase the energy density of the battery cell. Therefore, 0.35 mm ≤ T2 ≤ 0.6 mm not only gives the battery cell better reliability but also better energy density.

[0020] In some embodiments of the first aspect of this application, the hardness of the connecting portion is greater than the hardness of the body portion.

[0021] In the above technical solution, the connection part has a higher hardness than the body part, resulting in better strength for the connection part, which in turn gives the first wall better strength, thus giving the outer casing higher strength and improving the reliability of the battery cell. When the connection part is located at the bottom of the electrode assembly and supports the electrode assembly, it helps to stably support the electrode assembly, thereby reducing the risk of or mitigating the degree of electrode assembly movement within the casing, and improving the reliability of the battery cell.

[0022] In some embodiments of the first aspect of this application, the wall thickness of the first transition portion is less than the distance between the third surface and the fourth surface.

[0023] In the above technical solution, the wall thickness of the first transition part is less than the distance between the third surface and the fourth surface, which facilitates the connection between the first transition part and the main body, as well as the connection between the first transition part and the connecting part, and also facilitates the manufacturing and forming of the first wall.

[0024] In some embodiments of the first aspect of this application, the wall thickness of the first transition portion is greater than or equal to the distance between the first surface and the second surface.

[0025] In the above technical solution, the wall thickness of the first transition portion is less than the distance between the third and fourth surfaces, which facilitates the connection between the first transition portion and the main body, as well as between the first transition portion and the connecting portion. This results in the first transition portion having better strength, making the connection between the main body and the connecting portion more reliable. Because the wall thickness of the first transition portion is less than the distance between the third and fourth surfaces, a gradual decrease in thickness from the main body to the connecting portion can be achieved.

[0026] In some embodiments of the first aspect of this application, the first transition portion is disposed around the body portion, and the connecting portion is disposed around the first transition portion.

[0027] In the above technical solution, by having the first transition portion surround the main body and the connecting portion surround the first transition portion, the connecting portion can limit the electrode assembly in the first direction at any position along the circumference of the first wall, thereby reducing or preventing the electrode assembly from moving in the first direction, and thus improving the reliability of the battery cell.

[0028] In some embodiments of the first aspect of this application, the connecting portion is located at the bottom of the electrode assembly along the first direction and supports the electrode assembly.

[0029] In the above technical solution, since the first surface of the connecting part is the surface of the first wall closest to the second wall, and the connecting part is located at the bottom of the electrode assembly and supports the electrode assembly along the first direction, the connecting part can restrict the electrode assembly in the first direction, which can prevent the electrode assembly from moving in the first direction or slow down the degree of movement of the electrode assembly in the first direction, thereby improving the reliability of the battery cell.

[0030] In some embodiments of the first aspect of this application, the housing further includes a sidewall surrounding the electrode assembly, the first wall and the second wall being respectively disposed at both ends of the sidewall along the first direction; the first wall further includes a second transition portion and an edge portion, the second transition portion connecting the edge portion and the connecting portion, the first surface being closer to the second wall than the edge portion along the first direction, the edge portion being located on the side of the sidewall opposite to the second wall and connected to the sidewall.

[0031] In the above technical solution, the second transition portion connects the edge portion and the connecting portion, reducing the risk of stress concentration between the edge portion and the connecting portion, which helps extend the service life of the casing and thus the service life of the battery cell. The first surface is closer to the second wall than the edge portion, and the edge portion is located on the side of the side wall away from the second wall and connected to the side wall, facilitating the connection between the edge portion and the side wall. During the assembly of the side wall and the first wall, the side wall can be positioned through the second transition portion and the connecting portion, thus facilitating the assembly and connection of the side wall and the first wall.

[0032] In some embodiments of the first aspect of this application, along the first direction, the surface of the edge portion that is away from the second wall is closer to the second wall than the third surface.

[0033] In the above technical solution, by placing the surface of the edge portion away from the second wall closer to the second wall than the third surface along the first direction, the risk of interference between the edge portion and the external structure of the battery cell is reduced, the risk of failure of the connection position between the side wall and the first wall portion due to external impact is reduced, and the reliability of the battery cell is improved.

[0034] In some embodiments of the first aspect of this application, the body portion has a weak portion that is configured to be at least partially destroyed when the pressure inside the housing reaches a threshold.

[0035] In the above technical solution, by setting a weak point in the body, the weak point can be at least partially damaged when the internal pressure of the casing reaches a threshold, thereby releasing the internal pressure of the casing and reducing the risk of battery cell explosions and fires, thus improving the reliability of the battery cell. Setting the weak point in the body reduces the risk of interference between the internal structure of the casing and the weak point, which could damage the weak point. Since the first surface is the surface of the first wall closest to the second wall, there is a distance between the fourth wall and the electrode assembly, thus creating a distance between the weak point and the electrode assembly. This provides space for the internal pressure of the casing to act on the weak point, facilitating immediate pressure relief and further improving the reliability of the battery cell.

[0036] In some embodiments of the first aspect of this application, the third surface is provided with a first groove, and the weak portion is formed on the bottom wall of the first groove.

[0037] In the above technical solution, by forming the weak portion on the bottom wall of the first groove provided on the third surface, there is a distance between the weak portion and the third surface along the first direction, which can reduce the risk of interference between the external structure of the casing and the weak portion, thus damaging the weak portion. Furthermore, the distance between the weak portion and the third surface along the first direction provides space for partial structural flipping of the main body after the weak portion is damaged, and also provides a discharge channel for substances discharged after the weak portion is damaged, facilitating immediate pressure relief and further improving the reliability of the battery cell.

[0038] In some embodiments of the first aspect of this application, a protrusion protruding from the fourth surface is formed at a position corresponding to the first groove in the body portion.

[0039] In the above technical solution, a protrusion protruding from the fourth surface is formed at the position corresponding to the first groove of the main body. The first groove can be formed by stamping, bending or other methods. The wall thickness of the main body will not be reduced due to the setting of the first groove. This makes the area of ​​the main body except for the weak part have good strength and also helps to improve the uniformity of the thickness of the main body.

[0040] In some embodiments of the first aspect of this application, the housing further includes a sidewall, and along the first direction, a second wall is connected to one end of the sidewall, the first wall and the sidewall are separately disposed, and an opening is formed at the end of the sidewall away from the second wall, and the first wall covers the opening.

[0041] In the above technical solution, the first wall covers the opening in the side wall, that is, the first wall and the side wall are set separately and connected, which facilitates the manufacturing and shaping of the first wall.

[0042] Secondly, embodiments of this application provide a battery device, including the battery cell described in any embodiment of the first aspect.

[0043] In the above technical solutions, the battery cell provided in any embodiment of the first aspect has a high energy density, thereby enabling the battery device including the battery cell to have a high energy density.

[0044] Thirdly, embodiments of this application provide an electrical device, including the battery cell provided in any embodiment of the first aspect or the battery device provided in any embodiment of the second aspect.

[0045] In the above technical solutions, the battery cell provided in any embodiment of the first aspect and the battery device provided in any embodiment of the second aspect have high energy density, which is beneficial to improving the power reliability of electrical equipment powered by the battery cell or the battery device. Attached Figure Description

[0046] 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.

[0047] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0048] Figure 2 is an exploded view of a battery device provided in some embodiments of this application;

[0049] Figure 3 is an exploded view of a single battery cell provided in some embodiments of this application;

[0050] Figure 4 is a cross-sectional view of a battery cell provided in some embodiments of this application;

[0051] Figure 5 is an enlarged view of point A1 in Figure 4;

[0052] Figure 6 is a schematic diagram of the structure of the first wall provided in some embodiments of this application;

[0053] Figure 7 is a cross-sectional view along line B1-B1 in Figure 6;

[0054] Figure 8 is an enlarged view of section A2 in Figure 7;

[0055] Figure 9 is an enlarged view of section A3 in Figure 7.

[0056] Icons: 1000 - Vehicle; 100 - Battery assembly; 10 - Housing; 11 - First housing; 12 - Second housing; 20 - Battery cell; 21 - Outer casing; 21' - Housing; 211 - First wall; 211' - End cap; 2111 - Body; 21111 - Third surface; 21112 - Fourth surface; 21113 - Weak point; 21114 - First groove; 21115 - Protrusion; 21116 - Second groove; 21117 - Sixth surface; 21118 - Reinforcing part; 2112 - Connecting part; 21121- First surface; 21122- Second surface; 2113- First transition part; 2114- Second transition part; 2115- Edge part; 21151- Fifth surface; 212- Second wall; 213- Side wall; 2131- Opening; 22- Electrode assembly; 221- Tab; 23- Electrode terminal; 24- Current collector; 25- Insulator; 200- Controller; 300- Motor; X- First direction; M1- Score groove; Q1- First recess; Q2- Second recess. Embodiments of the present invention

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] In this application, "multiple" means two or more (including two).

[0064] 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.

[0065] 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.

[0066] 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.

[0067] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector.

[0068] 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.

[0069] 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.).

[0070] 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 0.05 At least one of O2 and its modified compounds.

[0071] 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.

[0072] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0073] 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 electrode, 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.).

[0074] As an example, the negative electrode sheet may include a negative current collector and a negative active material disposed on at least one surface of the negative current collector.

[0075] 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.

[0076] 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.

[0077] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0078] 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.

[0079] 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.

[0080] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0085] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0086] As an example, polymer solid electrolytes can be polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0087] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0088] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0089] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0090] In some implementations, the electrode assembly is a stacked structure.

[0091] As an example, multiple positive and negative electrode plates can be set, and multiple positive and multiple negative electrode plates can be stacked alternately.

[0092] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0093] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0094] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0095] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0096] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0097] 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.

[0098] 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, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0099] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0100] 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.

[0101] 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.

[0102] As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0103] 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.

[0104] 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.

[0105] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0106] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] In related technologies, a battery cell includes a casing and an electrode assembly. The casing includes a first wall and a second wall disposed opposite to each other along a first direction. The electrode assembly is housed within the casing and located between the first wall and the second wall. The first wall includes a body portion, a connecting portion, and a first transition portion connected to the body portion and the connecting portion. Along the first direction, the connecting portion has a first surface and a second surface disposed opposite to each other, the first surface being the surface of the first wall closest to the second wall. The body portion has a third surface and a fourth surface disposed opposite to each other, the third surface being the surface of the first wall furthest from the second wall. Since the distance between the first surface and the second surface is the same as the distance between the third surface and the fourth surface, the distance between the first surface and the third surface is relatively large, resulting in a larger overall size of the first wall portion in the first direction. This causes the first wall to occupy more space inside the casing, leading to a decrease in the space utilization rate of the battery cell in the first direction and a decrease in the energy density of the battery cell.

[0111] Based on the above considerations, in order to improve the energy density of a single battery cell, this application provides a single battery cell, which includes a housing and an electrode assembly. The housing includes a first wall and a second wall disposed opposite to each other along a first direction X. The electrode assembly is housed within the housing and is located between the first wall and the second wall. The first wall includes a body portion, a connecting portion, and a first transition portion connected together. The first transition portion connects the body portion and the connecting portion. Along the first direction, the connecting portion has a first surface and a second surface disposed opposite to each other. The first surface is the surface of the first wall closest to the second wall. The body portion has a third surface and a fourth surface disposed opposite to each other. The third surface is the surface of the first wall furthest from the second wall. The fourth surface is further away from the second wall than the first surface. The distance between the first surface and the second surface is less than the distance between the third surface and the fourth surface.

[0112] Along the first direction, the connecting portion has opposing first and second surfaces, where the first surface is the surface of the first wall closest to the second wall. The connecting portion can limit the electrode assembly in the first direction, reducing or preventing movement of the electrode assembly in the first direction, thereby improving the reliability of the battery cell. The body portion has opposing third and fourth surfaces, where the third surface is the surface of the first wall furthest from the second wall. The distance between the first and third surfaces is the maximum dimension of the first wall in the first direction. By making the distance between the first and second surfaces smaller than the distance between the third and fourth surfaces, the distance between the first and second surfaces is reduced, which helps to decrease the distance between the first and third surfaces in the first direction, thereby helping to reduce the maximum dimension of the first wall in the first direction.

[0113] 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.

[0114] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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 a battery cell 20, with the housing 10 used to house the battery cell 20.

[0119] 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 11 and a second housing 12, which are interlocked. The first housing 11 and the second housing 12 can have various shapes, such as cuboids or cylinders. The first housing 11 can be a hollow structure open on one side, and the second housing 12 can also be a hollow structure open on one side. The open side of the second housing 12 interlocks with the open side of the first housing 11, thus forming a housing 10 with an enclosed space. Alternatively, the first housing 11 can be a hollow structure open on one side, and the second housing 12 can be a plate-like structure, with the second housing 12 interlocked with the open side of the first housing 11, thus forming a housing 10 with an accommodating space.

[0120] 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.

[0121] In some embodiments, the battery device 100 may further include a busbar (not shown in the figure), through which multiple battery cells 20 can be electrically connected to each other to achieve series, parallel, or mixed connection of multiple battery cells 20. The busbar can be a metal conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0122] Please refer to Figures 3 and 4. Figure 3 is an exploded view of a battery cell 20 provided in some embodiments of this application; Figure 4 is a cross-sectional view of a battery cell 20 provided in some embodiments of this application. The battery cell 20 may include a housing 21 and an electrode assembly 22, with the electrode assembly 22 housed within the housing 21.

[0123] In some embodiments, the housing 21 may include a housing 21' and an end cap 211', the housing having an opening 2131, and the end cap 211' closing the opening 2131 of the housing. Here, "closed" means to cover or shut, and can be either sealed or unsealed.

[0124] The housing 21' is a component used to house the electrode assembly 22. The housing 21' can be a hollow structure with an opening 2131 at one end, or it can be a hollow structure with openings 2131 at both opposite ends. The housing 21' can have various shapes, such as cylindrical or cuboid. The housing 21' can be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy. The electrode assembly 22 can be partially or completely located within the housing 21'.

[0125] The end cap 211' and the housing 21' together define a receiving space for accommodating the electrode assembly 22 and other components. The end cap 211' can be connected to the housing by welding, rolling, or other methods to close the opening 2131 of the housing 21'. The shape of the end cap 211' can be adapted to the shape of the housing 21'. For example, if the housing 21' is a cuboid structure, the end cap 211' can be a rectangular plate structure adapted to the housing 21'; or if the housing 21' is a cylindrical structure, the end cap 211' can be a circular plate structure adapted to the housing 21'. The end cap 211' can also be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The materials of the end cap 211' and the housing 21' can be the same or different.

[0126] In an embodiment where the housing 21' has an opening 2131 at one end, one end cap 211' may be provided. In an embodiment where the housing 21' has openings 2131 at both opposite ends, two end caps 211' may be provided, with the two end caps 211' respectively closing the two openings 2131 of the housing 21', and the two end caps 211' and the housing 21' together defining the receiving space.

[0127] In some embodiments, the battery cell 20 may further include electrode terminals 23, which are disposed on the housing 21 and are used for electrical connection with the tabs 221 of the electrode assembly 22 to input or output electrical energy of the battery cell 20. The electrode terminals 23 may be disposed on the housing of the housing 21 or on the end cap of the housing 21. The electrode terminals 23 and the tabs 221 may be directly connected, for example, by welding. Alternatively, the electrode terminals 23 and the tabs 221 may be indirectly connected, for example, through a current collector 24. The current collector 24 may be a metallic conductor, such as copper, iron, aluminum, steel, or aluminum alloy.

[0128] As an example, as shown in Figures 3 and 4, one end of the housing 21' forms an opening 2131. There is one end cap 211' within the housing 21, which closes one opening 2131 of the housing 21'. The housing 21' has a bottom wall (second wall 212) opposite to the end cap 211'. An electrode terminal 23 is provided on the bottom wall of the housing 21'. The end of the electrode assembly 22 facing the electrode terminal 23 has a tab 221, which is electrically connected to the electrode terminal 23 via a current collector 24. The end of the electrode assembly 22 facing the end cap 211' has another tab 221, which is also electrically connected to the end cap 211' via another current collector 24.

[0129] As shown in Figures 3-5, the battery cell 20 includes a housing 21 and an electrode assembly 22. The housing 21 includes a first wall 211 and a second wall 212 disposed opposite to each other along a first direction X. The electrode assembly 22 is housed within the housing 21 and is located between the first wall 211 and the second wall 212. The first wall 211 includes a connected body portion 2111, a connecting portion 2112, and a first transition portion 2113. The first transition portion 2113 connects the body portion 2111 and the connecting portion 2112. Along the first direction X, the connecting portion 2112 has a first surface 211 disposed opposite to each other. 21 and second surface 21122, the first surface 21121 is the surface of the first wall 211 that is closest to the second wall 212, the body part 2111 has a third surface 21111 and a fourth surface 21112 that are disposed opposite to each other, the third surface 21111 is the surface of the first wall 211 that is furthest from the second wall 212, the fourth surface 21112 is further away from the second wall 212 than the first surface 21121, the distance between the first surface 21121 and the second surface 21122 is smaller than the distance between the third surface 21111 and the fourth surface 21112.

[0130] As shown in Figures 3 and 4, the outer casing 21 also includes a sidewall 213, which surrounds the outer periphery of the electrode assembly 22. The first wall 211 and the second wall 212 are respectively connected to the two ends of the sidewall 213 along the first direction X.

[0131] In some embodiments, the first wall 211 and the side wall 213 can be integrally formed, and the first wall 211 and the side wall 213 together form the aforementioned housing. An opening 2131 is formed at the end of the side wall 213 opposite to the first wall 211, and a second wall 212 is provided to cover the opening 2131 at the end of the side wall 213 opposite to the first wall 211. It can be understood that the second wall 212 serves as an end cap 211' of the housing 21.

[0132] In other embodiments, the second wall 212 and the side wall 213 can be integrally formed, thus the second wall 212 and the side wall 213 together form the aforementioned shell. An opening 2131 is formed at the end of the side wall 213 opposite to the second wall 212. The first wall 211 and the side wall 213 are separately disposed but connected. The first wall 211 covers the opening 2131 at the end of the side wall 213 opposite to the first wall 211. It can be understood that the first wall 211 serves as an end cap 211' for the outer shell 21. Figures 3 and 4 show the case where the first wall 211 is an end cap 211'.

[0133] In other embodiments, the first wall 211 and the second wall 212 are both separately disposed and connected to the side wall 213. The side wall 213 forms openings 2131 at both ends along the first direction X, and the first wall 211 and the second wall 212 respectively cover the two openings 2131 of the side wall 213.

[0134] The battery cell 20 may include two electrode terminals 23, which are respectively disposed on the first wall 211 and the second wall 212. The first wall 211 and the second wall 212 are insulated from their respective electrode terminals 23. The two tabs 221 of opposite polarity of the electrode assembly 22 are electrically connected to the two electrode terminals 23 respectively.

[0135] Of course, the battery cell 20 may also include an electrode terminal 23. The electrode terminal 23 is insulated from one of the first wall 211 and the second wall 212, and a tab 221 is electrically connected to the electrode terminal 23. The other of the second wall 212 and the first wall 211 is electrically connected to the other tab 221. As shown in Figures 3 and 4, the battery cell 20 includes an electrode terminal 23, which is insulated from the second wall 212 by an insulating member 25. One tab 221 is electrically connected to the electrode terminal 23, and the other tab 221 is electrically connected to the first wall 211. The insulating member 25 can be a sealant, an insulating nail, etc.

[0136] The first wall 211 may be located at the upper end of the electrode assembly 22, while the second wall 212 is located at the bottom wall of the electrode assembly 22 and supports the electrode assembly 22.

[0137] The second wall 212 may be located at the upper end of the electrode assembly 22, while the first wall 211 is located at the bottom wall of the electrode assembly 22 and supports the electrode assembly 22.

[0138] The first wall 211 can be a one-piece molded structure. For example, the first wall 211 can be a structure formed by one-piece molding methods such as stamping, bending, or casting. Of course, the first wall 211 can also be formed by other methods.

[0139] Both the first surface 21121 and the fourth surface 21112 are located inside the housing 21. Along the first direction X, the connecting portion 2112 protrudes from the fourth surface 21112, so that the first surface 21121 is closer to the second wall 212 than the fourth surface 21112.

[0140] In embodiments where the first wall 211 is electrically connected to the tab 221, the tab 221 can be connected to the connecting portion 2112. The tab 221 can be directly connected to the connecting portion 2112, for example, by welding the tab 221 to the connecting portion 2112. The tab 221 can also be indirectly connected to the connecting portion 2112, for example, by connecting the tab 221 to the connecting portion 2112 with conductive adhesive or by connecting the current collector 24. As shown in FIG. 5, a portion of the current collector 24 overlaps with the first surface 21121, and the current collector 24 can be welded to the connecting portion 2112 or connected with conductive adhesive, etc. Another portion of the current collector 24 is connected to the tab 221, for example, by welding the current collector 24 to the tab 221 or by connecting it with conductive adhesive, etc.

[0141] Both the second surface 21122 and the third surface 21111 are located outside the outer casing 21. Along the first direction X, the body portion 2111 protrudes from the second surface 21122, so that the third surface 21111 is further away from the second wall 212 than the second surface 21122. Since the second surface 21122 can be further away from the second wall 212 than the fourth surface 21112 along the first direction X, a portion of the connecting portion 2112 protrudes from the fourth surface 21112 in the direction from the first wall 211 to the second wall 212.

[0142] Along the first direction X, the second surface 21122 can be closer to the second wall 212 than the fourth surface 21112, or the distance between the second surface 21122 and the second wall 212 can be the same as the distance between the fourth surface 21112 and the second wall 212. In this case, along the direction from the first wall 211 to the second wall 212, the connecting part 2112 completely protrudes from the fourth surface 21112.

[0143] The third surface 21111 can serve as the end face of the battery cell 20 in the first direction X, and the third surface 21111 can contact the external structure of the battery cell 20. In the embodiment where the first wall 211 is located at the bottom of the electrode assembly 22 and supports the electrode assembly 22, the third surface 21111 can contact the housing 10 when the battery cell 20 is placed inside the housing 10.

[0144] Understandably, the first surface 21121 and the third surface 21111 are the two surfaces of the first wall 211 that are furthest apart in the first direction X. The distance between the first surface 21121 and the third surface 21111 in the first direction X is the maximum dimension of the first wall 211 in the first direction X.

[0145] Along the first direction X, the connecting portion 2112 has a first surface 21121 and a second surface 21122. The first surface 21121 is the surface of the first wall 211 that is closest to the second wall 212. The connecting portion 2112 can limit the electrode assembly 22 in the first direction X, reduce the degree of movement of the electrode assembly 22 in the first direction X or prevent the electrode assembly 22 from moving in the first direction X, thereby improving the reliability of the battery cell 20. The main body 2111 has a third surface 21111 and a fourth surface 21112 disposed opposite to each other. The third surface 21111 is the surface of the first wall 211 furthest from the second wall 212. The distance between the first surface 21121 and the third surface 21111 is the maximum dimension of the first wall 211 in the first direction X. Since the distance between the first surface 21121 and the second surface 21122 is smaller than the distance between the third surface 21111 and the fourth surface 21112, the distance between the first surface 21121 and the second surface 21122 is smaller. This helps to reduce the distance between the first surface 21121 and the third surface 21111 in the first direction X, thereby helping to reduce the maximum dimension of the first wall 211 in the first direction X. This reduces the internal space occupied by the first wall 211 in the first direction X, which helps to improve the utilization rate of the internal space of the casing 21, and thus helps to improve the energy density of the battery cell 20.

[0146] As shown in Figures 5 and 8, in some embodiments, along the first direction X, the distance between the first surface 21121 and the third surface 21111 is T, and the distance between the third surface 21111 and the fourth surface 21112 is T1, where 0.35≤T1 / T≤0.45.

[0147] For example, T1 / T can be 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, etc.

[0148] With a fixed distance between the third surface 21111 and the fourth surface 21112, the larger T1 / T is, the smaller T is, and the smaller the overall size of the first wall 211 in the first direction X is. Therefore, T1 / T ≥ 0.35, which makes the overall size of the first wall 211 in the first direction X smaller, reducing the space occupied by the first wall 211 in the internal space of the outer casing 21 in the first direction X, which is beneficial to improving the utilization rate of the internal space of the outer casing 21, thereby improving the energy density of the battery cell 20. With a fixed distance between the third surface 21111 and the fourth surface 21112, a smaller T1 / T results in a larger T, leading to a larger dimension of the first wall 211 in the first direction X. Therefore, T1 / T ≤ 0.45, which makes the ratio of the distance between the first surface 21121 and the fourth surface 21112 in the first direction X to the distance between the first surface 21121 and the third surface 21111 in the first direction X larger. This results in a larger protrusion of the connecting portion 2112 from the fourth surface 21112 in the first direction X, facilitating the limiting of the electrode assembly 22 in the first direction X by the connecting portion 2112, reducing or preventing the electrode assembly 22 from shifting in the first direction X, thereby improving the reliability of the battery cell 20. Therefore, 0.35 ≤ T1 / T ≤ 0.45 can improve both the reliability and energy density of the battery cell 20.

[0149] As shown in Figures 5-8, in some embodiments, along the first direction X, the distance between the first surface 21121 and the third surface 21111 is T, and the distance between the first surface 21121 and the second surface 21122 is T2, where 0.32≤T2 / T≤0.4.

[0150] For example, T2 / T can be 0.32, 0.325, 0.33, 0.335, 0.34, 0.345, 0.35, 0.355, 0.36, 0.365, 0.37, 0.375, 0.38, 0.385, 0.39, 0.395, 0.4, etc.

[0151] By setting T2 / T≥0.32, the distance between the first surface 21121 and the second surface 21122 can be increased, so that the connecting part 2112 has better strength, which is beneficial to improving the strength of the first wall 211. Alternatively, the distance between the first surface 21121 and the third surface 21111 can be decreased, thereby reducing the overall size of the first wall in the first direction and reducing the space occupied by the first wall in the internal space of the casing in the first direction, which is beneficial to improving the utilization rate of the internal space of the casing and thus improving the energy density of the battery cell. By setting T2 / T≤0.42, the distance between the first surface 21121 and the second surface 21122 can be decreased, thereby reducing the space occupied by the first wall 211 in the internal space of the casing 21 in the first direction X, which is beneficial to improving the utilization rate of the internal space of the casing 21. Therefore, 0.32≤T2 / T≤0.4 can improve both the reliability and the energy density of the battery cell 20.

[0152] In some embodiments, the distance between the first surface 21121 and the second surface 21122 is T2, and the distance between the third surface 21111 and the fourth surface 21112 is T1, where 0.65≤T2 / T1≤0.85.

[0153] For example, T2 / T1 can be 0.65, 0.68, 0.70, 0.72, 0.75, 0.78, 0.80, 0.82, 0.85, etc.

[0154] By setting T2 / T1≥0.65, the difference between the distance between the first surface 21121 and the second surface 21122 and the distance between the third surface 21111 and the fourth surface 21112 can be reduced, resulting in higher strength for the connecting part 2112 and thus better strength for the first wall 211, thereby improving the reliability of the battery cell 20. By setting T2 / T1≤0.85, the distance between the first surface 21121 and the second surface 21122 is sufficiently small, thereby reducing the overall size of the first wall 211 in the first direction X and reducing the space occupied by the first wall 211 in the internal space of the outer casing 21 in the first direction X. This is beneficial to improving the utilization rate of the internal space of the outer casing 21, thereby improving the energy density of the battery cell 20. Therefore, 0.65≤T2 / T1≤0.85 results in the battery cell 20 having higher reliability and energy density.

[0155] Please continue to refer to Figures 5-8. In some embodiments, along the first direction X, the distance between the first surface 21121 and the third surface 21111 is T, where 1.1mm≤T≤1.6mm.

[0156] For example, T can be 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, etc.

[0157] With the distance between the first surface 21121 and the third surface 21111 in the first direction X being greater than or equal to 1.1 mm, the first wall 211 has good strength, thereby giving the outer casing 21 high strength and improving the reliability of the battery cell 20. With the distance between the first surface 21121 and the third surface 21111 in the first direction X being less than or equal to 1.6 mm, it is beneficial to reduce the maximum size of the first wall 211 in the first direction X, thereby reducing the internal space occupied by the first wall 211 in the first direction X, which is beneficial to improving the utilization rate of the internal space of the outer casing 21, and thus beneficial to improving the energy density of the battery cell 20. Therefore, 1.1 mm ≤ T ≤ 1.6 mm ensures that the battery cell 20 has both good reliability and good energy density.

[0158] Please continue referring to Figures 5-8. In some embodiments, along the first direction X, the distance between the third surface 21111 and the fourth surface 21112 is T1, 0.35mm≤T1≤0.8mm.

[0159] For example, T1 can be 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, etc.

[0160] By ensuring that the distance between the third surface 21111 and the fourth surface 21112 along the first direction X is greater than or equal to 0.35 mm, the body portion 2111 has better strength, which in turn makes the first wall 211 stronger, resulting in higher strength for the outer casing 21 and improved reliability of the battery cell 20. By ensuring that the distance between the third surface 21111 and the fourth surface 21112 along the first direction X is less than or equal to 0.8 mm, the maximum size of the body portion 2111 in the first direction X is reduced, thus reducing the space occupied by the body portion 2111 in the internal space of the outer casing 21 in the first direction X. This, in turn, reduces the space occupied by the first wall 211 in the internal space of the outer casing 21 in the first direction X, thereby improving the utilization rate of the internal space of the outer casing 21 and ultimately increasing the energy density of the battery cell 20. Therefore, 0.35 mm ≤ T1 ≤ 0.8 mm ensures both good reliability and good energy density for the battery cell 20.

[0161] In some embodiments, 0.55mm ≤ T1 ≤ 0.65mm.

[0162] For example, T1 can be 0.55mm, 0.56mm, 0.57mm, 0.58mm, 0.59mm, 0.61mm, 0.62mm, 0.63mm, 0.64mm, 0.65mm, etc.

[0163] By ensuring that the distance between the third surface 21111 and the fourth surface 21112 along the first direction X is greater than or equal to 0.55 mm, the body portion 2111 has better strength, which in turn makes the first wall 211 stronger, resulting in higher strength of the outer casing 21 and further improving the reliability of the battery cell 20. By ensuring that the distance between the third surface 21111 and the fourth surface 21112 along the first direction X is less than or equal to 0.65 mm, the maximum size of the body portion 2111 in the first direction X is reduced, thereby reducing the space occupied by the body portion 2111 in the internal space of the outer casing 21 in the first direction X. This also reduces the space occupied by the first wall 211 in the internal space of the outer casing 21 in the first direction X, further improving the utilization rate of the internal space of the outer casing 21 and thus further increasing the energy density of the battery cell 20. Therefore, 0.55 mm ≤ T1 ≤ 0.65 mm results in both better reliability and higher energy density for the battery cell 20.

[0164] Please continue referring to Figures 5-8. In some embodiments, along the first direction X, the distance between the first surface 21121 and the second surface 21122 is T2, 0.25mm≤T2≤0.7mm;

[0165] For example, T2 can be 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, etc.

[0166] By ensuring that the distance between the first surface 21121 and the second surface 21122 along the first direction X is greater than or equal to 0.25 mm, the connecting portion 2112 has better strength, which in turn makes the first wall 211 stronger, resulting in higher strength of the outer casing 21 and improved reliability of the battery cell 20. The larger distance between the first surface 21121 and the second surface 21122 also facilitates connection of the connecting portion 2112 to other structures (current collector 24). Furthermore, by ensuring that the distance between the first surface 21121 and the second surface 21122 along the first direction X is less than or equal to 0.7 mm, the maximum size of the connecting portion 2112 in the first direction X is reduced, thereby reducing the space occupied by the connecting portion 2112 in the internal space of the outer casing 21 in the first direction X. This also reduces the space occupied by the first wall 211 in the internal space of the outer casing 21 in the first direction X, further improving the utilization rate of the internal space of the outer casing 21 and thus increasing the energy density of the battery cell 20. Therefore, 0.25mm≤T2≤0.7mm not only ensures good reliability of the battery cell 20, but also ensures good energy density of the battery cell 20.

[0167] In some embodiments, 0.35mm ≤ T2 ≤ 0.6mm.

[0168] For example, T2 can be 0.35mm, 0.32mm, 0.33mm, 0.34mm, 0.36mm, 0.38mm, 0.42mm, 0.46mm, 0.48mm, 0.52mm, 0.54mm, 0.56mm, 0.58mm, 0.6mm, etc.

[0169] By ensuring that the distance between the first surface 21121 and the second surface 21122 along the first direction X is greater than or equal to 0.35 mm, the connecting portion 2112 has better strength, which in turn makes the first wall 211 stronger, resulting in higher strength of the outer casing 21 and further improving the reliability of the battery cell 20. By ensuring that the distance between the first surface 21121 and the second surface 21122 along the first direction X is less than or equal to 0.6 mm, the maximum size of the connecting portion 2112 in the first direction X is further reduced, thus reducing the space occupied by the connecting portion 2112 in the internal space of the outer casing 21 in the first direction X. This, in turn, reduces the space occupied by the first wall 211 in the internal space of the outer casing 21 in the first direction X, improving the utilization rate of the internal space of the outer casing 21 and further increasing the energy density of the battery cell 20. Therefore, 0.35 mm ≤ T2 ≤ 0.6 mm results in both better reliability and higher energy density for the battery cell 20.

[0170] In some embodiments, the hardness of the connecting portion 2112 is greater than the hardness of the body portion 2111.

[0171] The hardness of the connecting part 2112 is the ability of the connecting part 2112 to locally resist the indentation of a hard object onto its surface. The hardness of the body part 2111 is the ability of the body part 2111 to locally resist the indentation of a hard object onto its surface.

[0172] The hardness of the connecting part 2112 is greater than that of the body part 2111. The materials of the body part 2111 and the connecting part 2112 can be different. The connecting part 2112 can be made of a material with higher hardness, while the body part 2111 can be made of a material with lower hardness.

[0173] The connecting portion 2112 and the main body portion 2111 can be made of the same material. The first wall 211 can be formed by stamping. In an embodiment where the first wall 211 is formed by stamping, by applying pressure to the substrate, the connecting portion 2112 can be formed into a structure with high hardness under the action of stamping force, and during the stamping process, the distance between the first surface 21121 and the second surface 21122 of the connecting portion 2112 is smaller than the distance between the third surface 21111 and the fourth surface 21112 of the main body portion 2111.

[0174] By ensuring that the hardness of the connecting portion 2112 is greater than that of the main body 2111, the connecting portion 2112 possesses better strength, which in turn gives the first wall 211 better strength, thereby giving the outer casing 21 higher strength and improving the reliability of the battery cell 20. When the connecting portion 2112 is located at the bottom of the electrode assembly 22 and supports it, it helps to stably support the electrode assembly 22, thereby reducing the risk of the electrode assembly 22 shifting within the outer casing 21 or mitigating the degree of such shifting, thus improving the reliability of the battery cell 20.

[0175] In some embodiments, the wall thickness of the first transition portion 2113 is less than the distance between the third surface 21111 and the fourth surface 21112.

[0176] As shown in Figures 5 and 8, the wall thickness of the first transition portion 2113 is the distance H1 between the inner and outer surfaces of the first transition portion 2113, where H1 < T1.

[0177] The smooth transition between the first transition portion 2113 and the main body portion 2111 reduces the risk of stress concentration between them and extends the service life of the outer casing 21. Similarly, the smooth transition between the first transition portion 2113 and the connecting portion 2112 reduces the risk of stress concentration between them and extends the service life of the outer casing 21.

[0178] Taking the stamping of the first wall 211 as an example, during the stamping process, the first transition part 2113 extends to a certain extent, so that the wall thickness of the first transition part 2113 is less than the distance between the third surface 21111 and the fourth surface 21112.

[0179] The wall thickness of the first transition portion 2113 is less than the distance between the third surface 21111 and the fourth surface 21112, which facilitates the connection between the first transition portion 2113 and the main body portion 2111, as well as the first transition portion 2113 and the connecting portion 2112, and facilitates the manufacturing and forming of the first wall 211.

[0180] As shown in Figures 5 and 8, in some embodiments, the wall thickness of the first transition portion 2113 is greater than or equal to the distance between the first surface 21121 and the second surface 21122.

[0181] That is, H1≥T2.

[0182] Taking the stamping of the first wall 211 as an example, during the stamping process, the connecting part 2112 will be squeezed towards the first transition part 2113 due to pressure, which will cause the wall thickness of the first transition part 2113 to be greater than the distance between the first surface 21121 and the second surface 21122.

[0183] By ensuring that the wall thickness of the first transition portion 2113 is less than the distance between the third surface 21111 and the fourth surface 21112, the connection between the first transition portion 2113 and the main body 2111, as well as between the first transition portion 2113 and the connecting portion 2112, is facilitated. This results in the first transition portion 2113 having better strength, making the connection between the main body 2111 and the connecting portion 2112 more reliable. Because the wall thickness of the first transition portion 2113 is less than the distance between the third surface 21111 and the fourth surface 21112, a gradual decrease in thickness from the main body 2111 to the connecting portion 2112 can be achieved.

[0184] As shown in Figures 5-8, in some embodiments, the first transition portion 2113 is disposed around the main body portion 2111, and the connecting portion 2112 is disposed around the first transition portion 2113.

[0185] The first transition portion 2113 is disposed around the main body portion 2111, that is, the first transition portion 2113 is a closed loop structure that extends circumferentially along the main body portion 2111 and closes. The inner edge of the first transition portion 2113 with a smaller circumference is connected to the outer peripheral surface of the main body portion 2111.

[0186] The connecting portion 2112 is provided around the main body portion 2111, that is, the connection is a closed loop structure that extends circumferentially along the main body portion 2111 and closes. The outer edge of the first transition portion 2113 with a larger circumference is connected to the inner circumferential surface of the connecting portion 2112.

[0187] With the first transition portion 2113 surrounding the main body portion 2111 and the connecting portion 2112 surrounding the first transition portion 2113, the connecting portion 2112 can limit the electrode assembly 22 in the first direction X at any position along the circumference of the first wall 211, thereby reducing the degree of movement of the electrode assembly 22 in the first direction X or preventing the electrode assembly 22 from moving in the first direction X, thereby improving the reliability of the battery cell 20.

[0188] Of course, in other embodiments, the first transition portion 2113 may also be connected to a local area of ​​the outer peripheral surface of the main body portion 2111, and the connecting portion 2112 may also be connected to a local area of ​​the outer peripheral surface of the first transition portion 2113.

[0189] As shown in FIG5, in some embodiments, the connecting portion 2112 is located at the bottom of the electrode assembly 22 along the first direction X and supports the electrode assembly 22.

[0190] The connecting portion 2112 is located below the electrode assembly 22 and bears the weight of the electrode assembly 22. The connecting portion 2112 can directly contact the electrode assembly 22, meaning it directly supports the electrode assembly 22. Alternatively, the connecting portion 2112 can indirectly contact the electrode assembly 22, meaning it indirectly supports the electrode assembly 22. For example, along the first direction X, a current collector 24 is provided between the connecting portion 2112 and the electrode assembly 22. The current collector 24 is located at the bottom of the electrode assembly 22, and the connecting portion 2112 is located at the bottom of the current collector 24, supporting the electrode assembly 22 through the current collector 24.

[0191] Since the first surface 21121 of the connecting part 2112 is the surface of the first wall 211 closest to the second wall 212, the connecting part 2112 is located at the bottom of the electrode assembly 22 and supports the electrode assembly 22 along the first direction X. The connecting part 2112 can restrict the electrode assembly 22 in the first direction X, which can prevent the electrode assembly 22 from moving in the first direction X or reduce the degree of movement of the electrode assembly 22 in the first direction X, thereby improving the reliability of the battery cell 20.

[0192] As shown in Figures 5-8, in some embodiments, the housing 21 further includes a sidewall 213 surrounding the electrode assembly 22. A first wall 211 and a second wall 212 are respectively disposed at both ends of the sidewall 213 along the first direction X. The first wall 211 further includes a second transition portion 2114 and an edge portion 2115. The second transition portion 2114 connects the edge portion 2115 and the connecting portion 2112. Along the first direction X, the first surface 21121 is closer to the second wall 212 than the edge portion 2115. The edge portion 2115 is located on the side of the sidewall 213 away from the second wall 212 and is connected to the sidewall 213.

[0193] Along the first direction X, the connecting portion 2112 protrudes from the surface of the edge portion 2115 facing the second wall 212. Along the first direction X, one end of the side wall 213 abuts against the surface of the edge portion 2115 facing the second wall 212 and is connected to the edge portion 2115. Of course, the inner peripheral surface of the side wall 213 may also abut against and be connected to the outer peripheral surface of the edge portion 2115.

[0194] The sidewall 213 and the edge portion 2115 can be welded, bonded, or otherwise connected.

[0195] The transition between the second transition portion 2114 and the edge portion 2115 is smooth, reducing the risk of stress concentration between the second transition portion 2114 and the edge, and extending the service life of the outer casing 21. Similarly, the smooth transition between the second transition portion 2114 and the connecting portion 2112 reduces the risk of stress concentration between them, and extends the service life of the outer casing 21.

[0196] In some embodiments, the second transition portion 2114 is disposed around the connecting portion 2112, that is, the second transition portion 2114 is a closed loop structure that extends circumferentially along the connecting portion 2112 and closes. The inner edge of the second transition portion 2114 with a smaller perimeter is connected to the outer peripheral surface of the connecting portion 2112.

[0197] The edge portion 2115 is provided around the second connecting portion 2112, that is, the edge is a closed loop structure that extends circumferentially along the second transition portion 2114 and closes. The inner edge of the edge portion 2115 with a smaller perimeter is connected to the outer peripheral surface of the second transition portion 2114.

[0198] The connecting portion 2112, the first transition portion 2113, and the second transition portion 2114 together define a first recessed portion Q1, which is provided around the body portion 2111. The first recessed portion Q1 can separate the edge portion 2115 and the body portion 2111. In embodiments where the edge portion 2115 is welded to the sidewall 213, the first recessed portion Q1 can avoid the risk of damage to the body portion 2111 from the welding heat of the sidewall 213 and the edge portion 2115, or reduce the damage to the body portion 2111 from the welding heat of the sidewall 213 and the edge portion 2115.

[0199] The second transition portion 2114 connects the edge portion 2115 and the connecting portion 2112, reducing the risk of stress concentration between them and extending the service life of the casing 21, which in turn extends the service life of the battery cell 20. The first surface 21121 is closer to the second wall 212 than the edge portion 2115. The edge portion 2115 is located on the side of the side wall 213 away from the second wall 212 and is connected to the side wall 213, facilitating the connection between the edge portion 2115 and the side wall 213. During the assembly of the side wall 213 and the first wall 211, the side wall 213 can be positioned by the second transition portion 2114 and the connecting portion 2112, thus facilitating the assembly and connection of the side wall 213 and the first wall 211.

[0200] In some embodiments, along the first direction X, the surface of the edge portion 2115 that is away from the second wall 212 is closer to the second wall 212 than the third surface 21111.

[0201] Along the first direction X, the surface of the edge portion 2115 that faces away from the second wall 212 is the fifth surface 21151.

[0202] Understandably, along the direction from the second wall 212 to the first wall 211, the fifth surface 21151 of the body portion 2111 protrudes from the edge portion 2115.

[0203] By placing the edge portion 2115, which is further away from the second wall 212 along the first direction X, closer to the second wall 212 than the third surface 21111, the risk of interference between the edge portion 2115 and the external structure of the battery cell 20 is reduced, the risk of failure of the connection between the side wall 213 and the first wall 211 due to external impact is reduced, and the reliability of the battery cell 20 is improved.

[0204] In other embodiments, along the first direction X, the surface of the edge portion 2115 away from the second wall 212 may also be flush with the third surface 21111.

[0205] As shown in Figures 7 and 9, in some embodiments, the body portion 2111 has a weak portion 21113, which is configured to be at least partially damaged when the pressure inside the housing 21 reaches a threshold.

[0206] The weakest part 21113 is the weakest section in the main body 2111. This weakest part 21113 can be formed by etching a groove M1 into the main body 2111, with the bottom wall of the groove M1 forming the weakest part 21113, as shown in Figure 9. The groove M1 is located on the sixth surface 21117 of the protrusion 21115. Alternatively, the weakest part 21113 can be formed using a weaker material.

[0207] When the pressure inside the casing 21 reaches a threshold, a small portion of the weak section 21113 breaks down to connect the inside and outside of the casing 21. This threshold design varies depending on design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell 20.

[0208] Along the first direction X, the surface of the weak portion 21113 facing the second wall 212 is at a distance from the electrode assembly 22. Along the first direction X, the surface of the weak portion 21113 facing the second wall 212 is farther away from the second wall 212 than the first surface 21121, reducing the risk of interference between the internal structure of the housing 21 and the weak portion 21113, thus damaging the weak portion 21113.

[0209] By providing a weak portion 21113 in the body portion 2111, the weak portion 21113 can be at least partially damaged when the internal pressure of the outer casing 21 reaches a threshold, thereby releasing the internal pressure of the outer casing 21 and reducing the risk of explosion or fire in the battery cell 20, thus improving the reliability of the battery cell 20. The weak portion 21113 in the body portion 2111 reduces the risk of interference between the internal structure of the outer casing 21 and the weak portion 21113, which could damage the weak portion 21113. Since the first surface 21121 is the surface of the first wall 211 closest to the second wall 212, there is a distance between the fourth wall and the electrode assembly 22, thus creating a distance between the weak portion 21113 and the electrode assembly 22. This provides space for the internal pressure of the outer casing 21 to act on the weak portion 21113, facilitating immediate pressure relief and further improving the reliability of the battery cell 20.

[0210] As shown in Figure 9, in some embodiments, the third surface 21111 is provided with a first groove 21114, and the weak part 21113 is formed on the bottom wall of the first groove 21114.

[0211] By forming the weak portion 21113 on the bottom wall of the first groove 21114 provided on the third surface 21111, the weak portion 21113 and the third surface 21111 are spaced apart along the first direction X. This reduces the risk of interference between the external structure of the housing 21 and the weak portion 21113, thus preventing damage to the weak portion 21113. Furthermore, the distance between the weak portion 21113 and the third surface 21111 along the first direction X provides space for partial structural flipping of the body portion 2111 after the weak portion 21113 is damaged, and also provides a discharge channel for substances discharged after the weak portion 21113 is damaged, facilitating immediate pressure relief and further improving the reliability of the battery cell 20.

[0212] As shown in Figures 7 and 9, in some embodiments, a protrusion 21115 protruding from the fourth surface 21112 is formed at the position corresponding to the first groove 21114 on the body portion 2111.

[0213] The protrusion 21115, the first transition portion 2113, and the body portion 2111 together define the second recess Q2, which surrounds the protrusion 21115. The second recess Q2 can act as a buffer between the protrusion 21115 and the connecting portion 2112, thereby improving the first wall 211's resistance to impact.

[0214] By forming a protrusion 21115 protruding from the fourth surface 21112 at a position corresponding to the first groove 21114 in the main body 2111, the first groove 21114 can be formed by stamping, bending or other methods. The wall thickness of the main body 2111 will not be reduced due to the setting of the first groove 21114, so that the area of ​​the main body 2111 except for the weak part 21113 has good strength, and it is also beneficial to improve the uniformity of the thickness of the main body 2111.

[0215] As shown in Figure 9, in some embodiments, a second groove 21116 is formed on the bottom surface of the first groove 21114. Along the first direction X, the protrusion 21115 has a sixth surface 21117 facing the second wall 212. A reinforcing portion 21118 protruding from the sixth surface 21117 is formed at the position of the protrusion 21115 corresponding to the second groove 21116.

[0216] Along the first direction X, the surface of the reinforcing part 21118 closest to the second wall 212 is farther away from the second wall 212 than the first surface 21121.

[0217] By forming a reinforcing part 21118 protruding from the sixth surface 21117 at a position corresponding to the bottom wall of the first groove 21114 and the second groove 21116, the first groove 21114 can be formed by stamping, bending or other methods. The wall thickness of the main body 2111 will not be reduced due to the setting of the first groove 21114, so that the area of ​​the main body 2111 except for the weak part 21113 has good strength, and it is also beneficial to improve the uniformity of the thickness of the main body 2111.

[0218] Please refer to Figures 3-5. In some embodiments, the outer casing 21 further includes a side wall 213. Along the first direction X, a second wall 212 is connected to one end of the side wall 213. The first wall 211 and the side wall 213 are separately disposed. An opening 2131 is formed at the end of the side wall 213 away from the second wall 212. The first wall 211 covers the opening 2131.

[0219] The first wall 211 is disposed over the opening 2131, meaning that the first wall 211 and the side wall 213 are separately disposed and connected. The first wall 211 can be an end cap of the outer casing 21. Here, "displaying" refers to covering or closing, which can be either sealed or unsealed.

[0220] The first wall 211 covers the opening 2131 of the side wall 213, that is, the first wall 211 and the side wall 213 are separately set and connected, which facilitates the manufacturing and shaping of the first wall 211.

[0221] This application also provides a battery device 100, which includes the battery cell 20 provided in any of the above embodiments.

[0222] The battery cell 20 provided in any of the above embodiments has a high energy density, thereby enabling the battery device 100 including the battery cell 20 to have a high energy density.

[0223] This application also provides an electrical device, which includes the battery cell 20 or the battery device 100 provided in any of the above embodiments.

[0224] The battery cell 20 or battery device 100 provides electrical energy for the operation of the electrical device.

[0225] The battery cell 20 and the battery device provided in any of the above embodiments have high energy density, which is beneficial to improving the power reliability of electrical equipment powered by the battery cell 20 or the battery device 100.

[0226] This application provides a battery cell 20, which includes a housing 21, an electrode assembly 22, and a current collector 24. The electrode assembly 22 is housed within the housing 21. The housing 21 includes a side wall 213, a first wall 211, and a second wall 212. Along a first direction X, the second wall 212 is connected to one end of the side wall 213, and the side wall 213 surrounds the outer periphery of the second side wall 213. The other end of the side wall 213 forms an opening 2131, and the first wall 211 covers the opening 2131. The first wall 211 is located at the bottom of the electrode assembly 22 and supports the electrode assembly 22.

[0227] The first wall 211 includes a body portion 2111, a connecting portion 2112, a first transition portion 2113, a second transition portion 2114, and an edge portion 2115. The first transition portion 2113 connects the body portion 2111 and the connecting portion 2112, and the second transition portion 2114 connects the edge portion 2115 and the connecting portion 2112. The first transition portion 2113 is disposed around the body portion 2111, the connecting portion 2112 is disposed around the first transition portion 2113, the second transition portion 2114 is disposed around the connecting portion 2112, and the edge portion 2115 is disposed around the second transition portion 2114. The opening 2131 end of the side wall 213 abuts against the end of the edge portion 2115 facing the second wall 212, and the edge portion 2115 is welded to the side wall 213. A current collector 24 connects the electrode tab 221 and the connecting portion 2112, and a portion of the current collector 24 is located between the electrode assembly 22 and the connecting portion 2112.

[0228] Along the first direction X, the connecting portion 2112 has a first surface 21121 and a second surface 21122 disposed opposite to each other. The first surface 21121 is the surface of the first wall 211 closest to the second wall 212. The body portion 2111 has a third surface 21111 and a fourth surface 21112 disposed opposite to each other. The third surface 21111 is the surface of the first wall 211 furthest from the second wall 212. The fourth surface 21112 is further away from the second wall 212 than the first surface 21121. The distance between the first surface 21121 and the second surface 21122 is less than the distance between the third surface 21111 and the fourth surface 21112. The third surface 21111 is further away from the second wall 212 than the surface of the edge portion 2115 that is far from the second wall 212. Along the first direction X, the distance between the third surface 21111 and the fourth surface 21112 is T1, where 0.35mm ≤ T1 ≤ 0.8mm; optionally, 0.55mm ≤ T1 ≤ 0.65mm. Along the first direction X, the distance between the first surface 21121 and the second surface 21122 is T2, where 0.25mm ≤ T2 ≤ 0.7mm; optionally, 0.35mm ≤ T2 ≤ 0.6mm.

[0229] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0230] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit this application. For those skilled in the art, this application can have various modifications and variations. 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 single battery cell, comprising: The outer casing includes a first wall and a second wall disposed opposite to each other along a first direction; An electrode assembly is housed within the housing and is located between the first wall and the second wall; The first wall includes a connected body portion, a connecting portion, and a first transition portion. The first transition portion connects the body portion and the connecting portion. Along the first direction, the connecting portion has a first surface and a second surface disposed opposite to each other. The first surface is the surface of the first wall closest to the second wall. The body portion has a third surface and a fourth surface disposed opposite to each other. The third surface is the surface of the first wall furthest from the second wall. The fourth surface is further away from the second wall than the first surface. The distance between the first surface and the second surface is less than the distance between the third surface and the fourth surface.

2. The battery cell as described in claim 1, wherein, Along the first direction, the distance between the first surface and the third surface is T, and the distance between the third surface and the fourth surface is T1, where 0.35 ≤ T1 / T ≤ 0.

45.

3. The battery cell as described in claim 1 or 2, wherein, Along the first direction, the distance between the first surface and the third surface is T, and the distance between the first surface and the second surface is T2, where 0.32 ≤ T2 / T ≤ 0.

4.

4. The battery cell according to any one of claims 1-3, wherein, The distance between the first surface and the second surface is T2, and the distance between the third surface and the fourth surface is T1, where 0.65 ≤ T2 / T1 ≤ 0.

85.

5. The battery cell according to any one of claims 1-4, wherein, Along the first direction, the distance between the first surface and the third surface is T, where 1.1 mm ≤ T ≤ 1.6 mm.

6. The battery cell according to any one of claims 1-5, wherein, Along the first direction, the distance between the third surface and the fourth surface is T1, where 0.35mm ≤ T1 ≤ 0.8mm; optionally, 0.55mm ≤ T1 ≤ 0.65mm.

7. The battery cell according to any one of claims 1-6, wherein, Along the first direction, the distance between the first surface and the second surface is T2, where 0.25mm ≤ T2 ≤ 0.7mm; optionally, 0.35mm ≤ T2 ≤ 0.6mm.

8. The battery cell according to any one of claims 1-7, wherein, The hardness of the connecting part is greater than that of the body part.

9. The battery cell according to any one of claims 1-8, wherein, The wall thickness of the first transition section is less than the distance between the third surface and the fourth surface.

10. The battery cell as described in claim 9, wherein, The wall thickness of the first transition portion is greater than or equal to the distance between the first surface and the second surface.

11. The battery cell according to any one of claims 1-10, wherein, The first transition portion is disposed around the main body portion, and the connecting portion is disposed around the first transition portion.

12. The battery cell according to any one of claims 1-11, wherein, Along the first direction, the connecting portion is located at the bottom of the electrode assembly and supports the electrode assembly.

13. The battery cell according to any one of claims 1-12, wherein, The housing also includes sidewalls surrounding the electrode assembly, with the first wall and the second wall respectively disposed at both ends of the sidewalls along the first direction; The first wall further includes a second transition portion and an edge portion. The second transition portion connects the edge portion and the connecting portion. Along the first direction, the first surface is closer to the second wall than the edge portion. The edge portion is located on the side of the side wall opposite to the second wall and is connected to the side wall.

14. The battery cell as described in claim 13, wherein, Along the first direction, the surface of the edge portion that is farther from the second wall is closer to the second wall than the third surface.

15. The battery cell according to any one of claims 1-14, wherein, The body portion has a weak portion, which is configured to be at least partially destroyed when the pressure inside the housing reaches a threshold.

16. The battery cell as described in claim 15, wherein, The third surface is provided with a first groove, and the weak part is formed on the bottom wall of the first groove.

17. The battery cell as claimed in claim 16, wherein, The body portion has a protrusion that protrudes from the fourth surface at a position corresponding to the first groove.

18. The battery cell according to any one of claims 1-17, wherein, The outer casing also includes a side wall. Along the first direction, the second wall is connected to one end of the side wall. The first wall and the side wall are separately disposed. An opening is formed at the end of the side wall away from the second wall, and the first wall covers the opening.

19. A battery device comprising a battery cell as described in any one of claims 1-18.

20. An electrical device comprising a battery cell as described in any one of claims 1-18 or a battery device as described in claim 19.

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