Shell, battery monomer, battery and electric equipment

Abstract

The embodiment of the invention provides a shell, a battery monomer, a battery and electric equipment, and belongs to the technical field of batteries. Wherein the shell is formed by bending a plate, the head end part and the tail end part of the plate are connected with each other so as to enclose to form an accommodating space with openings at two opposite ends, and the accommodating space is used for accommodating an electrode assembly of the battery monomer. The shell is formed by bending the plate, the head end wall and the tail end wall of the plate are connected together, the shell with the openings in the two opposite ends can be formed, the forming mode of the shell is simple, and the forming difficulty of the shell is effectively reduced.

Description

Housing, battery cells, batteries and electrical equipment Technical Field

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

[0002] With the development of new energy technology, batteries are used more and more widely, for example, in mobile phones, laptops, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and power tools.

[0003] In a battery cell, the shell is an important component of the battery cell, and its molding difficulty directly affects the production cost of the battery cell. Therefore, how to effectively reduce the molding difficulty of the shell is an urgent problem to be solved in battery technology.

[0004] Summary of the Invention

[0005] The embodiments of the present application provide a housing, a battery cell, a battery, and an electrical device, which can effectively reduce the difficulty of molding the housing.

[0006] In a first aspect, an embodiment of the present application provides a shell for a battery cell. The shell is formed by bending a plate. The head and tail ends of the plate are connected to each other to enclose a receiving space with openings at opposite ends. The receiving space is used to accommodate the electrode assembly of the battery cell.

[0007] In the above technical solution, the shell is formed by bending a plate, and the head and tail end walls of the plate are connected to each other to form a shell with openings at opposite ends. The shell forming method is simple, which effectively reduces the difficulty of forming the shell.

[0008] In some embodiments, the housing includes multiple walls that enclose a housing space. The housing is provided with a pressure relief mechanism, with the connection points at the two ends and the pressure relief mechanism located on two different walls. This avoids locating the connection points and the pressure relief mechanism on the same wall, reducing the impact of the connection points on the pressure relief mechanism and improving its reliability, enabling it to properly relieve pressure in the event of thermal runaway of a battery cell.

[0009] In some embodiments, the plurality of walls include a first wall and a second wall disposed opposite each other, the pressure relief mechanism is located on the first wall, and the connection location is located on the second wall. This allows the pressure relief mechanism and the connection location to be located on two opposing walls, respectively, further separating the pressure relief mechanism and the connection location in the circumferential direction of the housing, further reducing the effect of the connection location on the pressure relief mechanism.

[0010] In some embodiments, the second wall portion includes a first connecting wall and a second connecting wall disposed opposite the first wall portion, wherein the first connecting wall and the second connecting wall each form two end portions. Thus, by connecting the first connecting wall and the second connecting wall, the first and second end portions of the plate are connected to each other, resulting in a simple structure and ease of connection of the two ends of the plate.

[0011] In some embodiments, the first connecting wall has a first end surface, and the second connecting wall has a second end surface. The first end surface and the second end surface are the end surfaces of the plate, respectively, and the first end surface and the second end surface are connected. On the one hand, the length of the plate can be reduced, saving materials and reducing production costs. On the other hand, the first end surface of the first connecting wall and the second end surface of the second connecting wall are connected to each other, making the second connecting wall more flat as a whole, thereby increasing the internal space of the housing and facilitating the improvement of the energy density of the battery cell.

[0012] In some embodiments, the first connecting wall and the second connecting wall are at least partially stacked and connected to each other along the thickness direction of the first wall portion. This can reduce the difficulty of connecting the first connecting wall and the second connecting wall, increase the connection area between the first connecting wall and the second connecting wall, and improve the connection strength between the first connecting wall and the second connecting wall.

[0013] In some embodiments, the housing further includes a third wall portion and a fourth wall portion disposed opposite each other, the third wall portion connecting the first wall portion and the first connecting wall, and the fourth wall portion connecting the first wall portion and the second connecting wall. Thus, the housing formed by the first wall portion, the second wall portion, the third wall portion, and the fourth wall portion generally has a quadrangular prism structure, which is simple in structure and easy to form.

[0014] In some embodiments, the maximum distance between the third wall portion and the fourth wall portion is A, and the minimum distance between the first wall portion and the second wall portion is B, where A<B. The pressure relief mechanism and the connection position are respectively located on two walls (the first wall portion and the second wall portion) that are farther apart, further reducing the influence of the connection position on the pressure relief mechanism. In addition, since A<B, when the electrode assembly expands, the first wall portion and the second wall portion are less affected by the electrode assembly than the third wall portion and the fourth wall portion. Since the pressure relief mechanism is located on the first wall portion, the expansion of the electrode assembly is not likely to block the pressure relief mechanism, reducing the risk that the expansion of the electrode assembly blocks the pressure relief mechanism, resulting in the pressure relief mechanism being unable to relieve pressure normally; since the connection position is located on the second wall portion, the risk of the shell being damaged at the connection position due to the expansion of the electrode assembly is reduced.

[0015] In some embodiments, the plurality of walls include a first wall, the pressure relief mechanism is provided separately from the housing, and the pressure relief mechanism is mounted on the first wall. The pressure relief mechanism is a component independent of the housing, and the pressure relief mechanism and the housing can be produced separately and then assembled, which improves production efficiency.

[0016] In some embodiments, the plurality of walls include a first wall, and the pressure relief mechanism is integrally formed with the first wall. This increases the reliability of the pressure relief mechanism, eliminates the need for a connection process between the pressure relief mechanism and the first wall, and reduces the production cost of the housing.

[0017] In some embodiments, the first wall portion is provided with a notch, and the first wall portion forms a pressure relief mechanism in the area where the notch is provided. By providing the notch on the first wall portion to form an integrated pressure relief mechanism, the pressure relief mechanism is formed in a simple manner and has low production cost.

[0018] In some embodiments, the first wall portion has a first inner surface facing the interior of the housing, and the scored groove is provided on the first inner surface. On the one hand, when the scored groove is formed on the first inner surface of the first wall portion, the outer surface of the first wall portion is less likely to be affected, thereby maintaining a smooth outer surface of the first wall portion. On the other hand, the scored groove is provided on the first inner surface of the first wall portion, and the groove wall of the scored groove is not exposed to the outside of the battery cell, thereby reducing the risk of oxidation of the first wall portion in the area where the scored groove is provided, thereby improving the stability of the integrated pressure relief mechanism.

[0019] In some embodiments, the first wall portion has a first outer surface facing away from the interior of the housing, and the notch is provided on the first outer surface. Thus, when the notch is formed on the first outer surface of the first wall portion, the notch is less likely to affect the inner surface of the first wall portion, thereby maintaining a smooth inner surface of the first wall portion.

[0020] In some embodiments, the first wall portion has a first inner surface facing the interior of the housing and a first outer surface facing away from the interior of the housing, and both the first inner surface and the first outer surface are provided with a scoring groove.

[0021] In some embodiments, the scored grooves provided on the first outer surface are arranged opposite to the scored grooves provided on the first inner surface. Thus, given a given thickness of the first wall and the pressure relief mechanism, the depth of the scored grooves on the first inner and first outer surfaces can be reduced, thereby reducing the forming force exerted on the first wall during the forming of the scored grooves and lowering the risk of cracks in the first wall.

[0022] In some embodiments, the first wall portion has a protrusion formed at the edge of the scored groove that protrudes from the first inner surface. The protrusion protruding from the first inner surface reinforces the area of ​​the first wall portion where the scored groove is provided, thereby strengthening the pressure relief mechanism, improving its fatigue resistance, and reducing the risk of damage to the first wall portion due to fatigue of the pressure relief mechanism under normal battery cell use.

[0023] In some embodiments, the first wall portion has a protrusion formed at the edge of the scored groove that protrudes from the first outer surface. The protrusion protruding from the first outer surface reinforces the area of ​​the first wall portion where the scored groove is provided, thereby strengthening the pressure relief mechanism, improving its fatigue resistance, and reducing the risk of damage to the first wall portion due to fatigue of the pressure relief mechanism under normal battery cell use.

[0024] In some embodiments, along the thickness direction of the first wall portion, the thickness of the first wall portion is D, the residual thickness of the first wall portion in the region where the notch is provided is H1, and H1 / D ≤ 0.7. When H1 / D > 0.7, the detonation pressure of the battery cell is too high, making it more difficult for the pressure relief mechanism to be destroyed during thermal runaway of the battery cell, and thus prone to untimely pressure relief. Therefore, H1 / D ≤ 0.7 can effectively improve the timeliness of battery cell pressure relief and reduce the risk of explosion due to thermal runaway of the battery cell.

[0025] In some embodiments, H1 is ≥ 0.05 mm. When H1 is less than 0.5 mm, under normal battery cell usage, the first wall portion is too thin in the area where the notched groove is located (the pressure relief mechanism), resulting in excessive stress. This can easily shorten the life of the pressure relief mechanism due to fatigue and creep, causing premature damage to the pressure relief mechanism and shortening the battery cell's service life. Therefore, setting H1 ≥ 0.05 mm reduces the risk of damage to the pressure relief mechanism under normal battery cell usage, thereby increasing the battery cell's service life.

[0026] In some embodiments, D is less than or equal to 0.6 mm, which makes the first wall thinner. When the outer dimensions of the housing are constant, the internal space of the housing can be increased, which is beneficial to improving the energy density of the battery cell.

[0027] In some embodiments, the scored groove includes a first groove section and a second groove section, wherein the first groove section intersects the second groove section. The intersection of the first and second groove sections results in more concentrated stress, making the shell more susceptible to damage at this intersection. This improves the shell's pressure relief sensitivity, allowing for timely pressure relief when the internal pressure of the battery cell reaches the detonation pressure. Given a constant detonation pressure for the battery cell, the depth of the scored groove can be appropriately reduced, increasing the residual thickness of the shell in the area where the scored groove is located, thereby improving the fatigue strength of the shell in the area where the scored groove is located.

[0028] In some embodiments, the notched groove further includes a third groove section, the first groove section and the third groove section are arranged opposite to each other, and the third groove section intersects with the second groove section. In this way, after the shell is split along the first groove section, the second groove section and the third groove section, it has a larger pressure relief area, thereby achieving large-area pressure relief. In addition, the intersection position of the third groove section and the second groove section is more concentrated, and the shell is more easily destroyed at the intersection position of the second groove section and the third groove section, thereby improving the pressure relief sensitivity of the shell and timely releasing pressure when the internal pressure of the battery cell reaches the detonation pressure. Similarly, when the detonation pressure of the battery cell is constant, the depth of the notched groove can be appropriately reduced, so that the residual thickness of the shell in the area where the notched groove is set is increased, thereby improving the fatigue strength of the shell in the area where the notched groove is set.

[0029] In some embodiments, the first slot segment, the second slot segment and the third slot segment are connected in sequence. The notched slot structure of this structure is simple and easy to form.

[0030] In some embodiments, the first and second slot segments intersect at a first position, which is offset from the ends of the first slot segment in its extension direction; the third slot segment intersects with the second slot segment at a second position, which is offset from the ends of the third slot segment in its extension direction. The areas of the housing located on both sides of the second slot segment can be opened after the housing is split along the first, second, and third slot segments, effectively improving the pressure relief efficiency of the housing.

[0031] In some embodiments, the first position is located at the midpoint of the first slot segment in the extension direction, and the second position is located at the midpoint of the third slot segment in the extension direction. In this way, the shell is more easily destroyed at the first and second positions, thereby improving the shell's pressure relief sensitivity and timeliness of pressure relief.

[0032] In some embodiments, the score groove is a groove extending along a non-closed trajectory.

[0033] In some embodiments, the notched groove is an arc-shaped groove. The arc-shaped groove has a simple structure and is easy to form. During the pressure relief process, the shell can quickly split along the arc-shaped groove, so that the area defined by the arc-shaped groove is quickly opened.

[0034] In some embodiments, the scored groove is a groove extending along a closed trajectory. During the pressure relief process, the shell can be split along the scored groove, so that the area defined by the scored groove can be opened in a detachable manner, thereby increasing the pressure relief area of ​​the shell and improving the pressure relief rate of the shell.

[0035] In some embodiments, the notched groove is an annular groove. The annular groove has a simple structure and is easy to form. During the pressure relief process, the shell can quickly split along the annular groove to quickly open the area defined by the annular groove.

[0036] In some embodiments, the openings at both ends of the housing are arranged relative to each other along a first direction, and the multiple walls include a first wall. The first wall is provided with multiple pressure relief mechanisms, and the multiple pressure relief mechanisms are arranged along the first direction. In this way, in the event of thermal runaway of a battery cell, pressure relief can be provided by the multiple pressure relief mechanisms on the first wall, improving the timeliness of pressure relief and enhancing the reliability of the battery cell. If a portion of the pressure relief mechanisms on the first wall is blocked or fails, pressure relief can be provided by the pressure relief mechanisms on another portion of the first wall, thereby improving the reliability of the battery cell.

[0037] In some embodiments, two pressure relief mechanisms are provided on the first wall portion, so that the housing has good pressure relief capability and reduces the production cost of the housing.

[0038] In some embodiments, the two pressure relief mechanisms are a first pressure relief mechanism and a second pressure relief mechanism. Along a first direction, the housing has a first open end and a second open end facing each other. The first pressure relief mechanism is closer to the first open end than the second pressure relief mechanism. The distance between the first and second pressure relief mechanisms is K1, the distance between the first pressure relief mechanism and the first open end is K2, and the distance between the second pressure relief mechanism and the second open end is K3, where K2 < K1 and K3 < K1. In the event of thermal runaway of a battery cell, emissions from the battery cell are more likely to accumulate in areas near the ends of the housing. Because K2 < K1 and K2 < K1, the first pressure relief mechanism is closer to the first open end and the second pressure relief mechanism is closer to the second open end. This allows emissions from the battery cell to be more easily discharged through the first and second pressure relief mechanisms, thereby improving the timeliness of pressure relief.

[0039] In some embodiments, the end surfaces of the plate are connected at both ends. This eliminates overlap after the two ends are connected, saving materials and reducing production costs. Furthermore, the connection of the end surfaces at both ends of the housing makes the housing smoother, increasing the internal space of the housing and improving the energy density of the battery cells.

[0040] In some embodiments, the two ends are welded together, so that the two ends have good connection strength and are more firmly connected.

[0041] In some embodiments, the housing includes multiple walls that enclose a receiving space, and the connection between the two ends is located on one wall. This can reduce the difficulty of connecting the two ends and improve the connection strength of the connection location.

[0042] In some embodiments, the wall thickness of the shell is L, where L is ≤ 0.6 mm. Thus, the shell formed by bending the sheet material is a thin-walled shell, which is beneficial for achieving lightweight battery cells. Given a given shell's outer dimensions, the thin-walled shell has a larger internal space, providing a larger accommodation space for the electrode assembly, thereby improving the energy density of the battery cells.

[0043] In some embodiments, the housing is a rectangular parallelepiped housing, which is suitable for rectangular parallelepiped battery cells and can meet the large capacity requirements of the battery cells.

[0044] In some embodiments, the openings at both ends of the housing are arranged opposite each other along the length of the housing. The length of the housing is a, the width of the housing is b, and the height of the housing is c, where b≤c≤a / 1.5. The housing is elongated, which helps to increase the energy density of the battery cell.

[0045] In some embodiments, the openings at both ends of the housing are arranged opposite to each other along the length of the housing, and the length of the housing is a, where a≥150 mm. A longer housing is beneficial for improving the energy density of the battery cell.

[0046] In some embodiments, a≥300 mm, thereby further improving the energy density of the battery cell.

[0047] In some embodiments, the housing is made of aluminum alloy, which is lightweight, has good ductility, and is easy to form.

[0048] In a second aspect, an embodiment of the present application provides a battery cell comprising an electrode assembly, an end cover, and a shell provided by any embodiment of the first aspect; the electrode assembly is accommodated in the accommodating space; the end cover corresponds to the opening one by one, and the end cover closes the opening.

[0049] In some embodiments, the housing includes a first wall portion, on which a pressure relief mechanism is disposed; the battery cell further includes a support member disposed between the first wall portion and the electrode assembly, the support member being configured to support the electrode assembly. The support member can bear the weight of the electrode assembly and separate the first wall portion from the electrode assembly, thereby reducing the impact of the electrode assembly on the pressure relief mechanism and improving the life of the pressure relief mechanism.

[0050] In some embodiments, a relief groove is provided on the side of the support member facing the first wall, and the projection of the pressure relief mechanism is located within the relief groove along the thickness direction of the first wall, thereby reducing the risk of the support member directly acting on the pressure relief mechanism and improving the life of the pressure relief mechanism.

[0051] In some embodiments, a relief groove is provided on the side of the support member facing the first wall portion. The first wall portion has a first inner surface facing the electrode assembly, and the first inner surface is provided with a notched groove. The first wall portion forms a pressure relief mechanism in the area where the notched groove is provided. The first wall portion has a protrusion formed at the edge of the notched groove, protruding from the first inner surface. The relief groove is configured to accommodate at least a portion of the protrusion. This makes the first wall portion and the support member more compact, freeing up more space for the electrode assembly and thereby increasing the energy density of the battery cells.

[0052] In some embodiments, along the thickness direction of the first wall, the height of the protrusion is H2, and the depth of the avoidance groove is H3, where H2 ≤ H3. This allows the protrusion to be completely accommodated within the avoidance groove. This, on the one hand, increases the contact area between the support member and the first wall, improving the stability of the support member within the housing; on the other hand, the protrusion is less susceptible to the force exerted by the support member, reducing the risk of the support member exerting force on the protrusion, thereby shortening the life of the pressure relief mechanism.

[0053] In a third aspect, an embodiment of the present application provides a battery, comprising a battery cell provided by any embodiment of the second aspect.

[0054] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising a battery cell provided by any one embodiment of the second aspect, wherein the battery cell is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0056] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0057] FIG2 is an exploded view of a battery provided in some embodiments of the present application;

[0058] FIG3 is an assembly diagram of a battery cell provided in some embodiments of the present application;

[0059] FIG4 is an exploded view of the battery cell shown in FIG3 ;

[0060] FIG5 is a partial cross-sectional view of the battery cell shown in FIG3 ;

[0061] FIG6 is a schematic structural diagram of a housing provided in some embodiments of the present application;

[0062] FIG7 is a schematic structural diagram of a housing before molding in some embodiments of the present application;

[0063] FIG8 is a schematic structural diagram of a housing provided in some other embodiments of the present application;

[0064] FIG9 is a cross-sectional view of the housing shown in FIG8 ;

[0065] FIG10 is a partial enlarged view of the housing shown in FIG9 at position C;

[0066] FIG11 is a cross-sectional view of a housing provided in some other embodiments of the present application;

[0067] FIG12 is a partial enlarged view of the housing shown in FIG11 at position F;

[0068] FIG13 is a cross-sectional view of a housing provided in some further embodiments of the present application;

[0069] FIG14 is a partial enlarged view of the housing shown in FIG13 at position I;

[0070] FIG15 is a partial enlarged view of a housing provided in some embodiments of the present application;

[0071] FIG16 is a partial enlarged view of a housing provided in some other embodiments of the present application;

[0072] FIG17 is a partial enlarged view of a housing provided in some other embodiments of the present application;

[0073] FIG18 is a partial enlarged view of a housing (with a protrusion provided on the first inner surface) provided in some embodiments of the present application;

[0074] FIG19 is a partial enlarged view of a housing (both the first inner surface and the first outer surface are provided with protrusions) provided in some embodiments of the present application;

[0075] FIG20 is a partial enlarged view of a housing (with a protrusion provided on the first outer surface) provided in some embodiments of the present application;

[0076] FIG21 is a schematic structural diagram of a first wall portion (with a V-shaped pressure relief groove) provided in some embodiments of the present application;

[0077] FIG22 is a schematic structural diagram of a first wall portion (the pressure relief groove is U-shaped) provided in some embodiments of the present application;

[0078] FIG23 is a schematic structural diagram of a first wall portion (with an H-shaped pressure relief groove) provided in some embodiments of the present application;

[0079] FIG24 is a schematic structural diagram of a first wall portion (the pressure relief groove is an arc-shaped groove) provided in some embodiments of the present application;

[0080] FIG25 is a schematic structural diagram of a first wall portion (the pressure relief groove is an annular groove) provided in some embodiments of the present application;

[0081] FIG26 is a schematic structural diagram of a first wall portion (the pressure relief groove is an annular groove) provided in yet other embodiments of the present application;

[0082] FIG27 is a schematic structural diagram of a housing provided in yet other embodiments of the present application;

[0083] FIG28 is a view of the housing shown in FIG27 taken along the direction of arrow M;

[0084] FIG29 is a partial enlarged view of position N of the housing shown in FIG27;

[0085] FIG30 is a schematic structural diagram of a housing provided in some further embodiments of the present application;

[0086] FIG31 is a front view of a battery cell provided in some embodiments of the present application;

[0087] FIG32 is a PP cross-sectional view of the battery cell shown in FIG31 ;

[0088] FIG33 is a partial enlarged view of the battery cell at position Q shown in FIG32 ;

[0089] FIG34 is a partial enlarged view of the battery cell at position S shown in FIG33 ;

[0090] FIG35 is a partially enlarged view of a battery cell provided in some other embodiments of the present application.

[0091] Icons: 1-shell; 11-shell; 111-accommodation space; 112-end; 1121-first end surface; 1122-second end surface; 113-wall; 1131-first wall; 11311-pressure relief hole; 11312-first inner surface; 11313-first outer surface; 1132-second wall; 11321-first connecting wall; 11322-second connecting wall; 11323-first surface; 11324-second surface; 11325-first connecting portion; 11326-second connecting portion; 11327-third connecting portion; 1133-third wall; 1134-fourth wall; 114-connection position; 115-first opening end; 116-second opening end; 12-end cover ;13-pressure relief mechanism;131-first pressure relief mechanism;132-second pressure relief mechanism;14-notched groove;141-first groove section;142-second groove section;143-third groove section;144-pressure relief area;1411-reinforcement rib;145-first position;155-second position;15-protrusion;151-second inner surface;2-electrode assembly;21-ear;3-electrode terminal;4-first insulating member;5-second insulating member;6-support member;61-avoidance groove;10-battery cell;20-housing;201-first part;202-second part;100-battery;200-controller;300-motor;1000-vehicle;X-first direction;Y-second direction;Z-third direction. DETAILED DESCRIPTION

[0092] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0093] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0094] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0095] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0096] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0097] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0098] The term "plurality" used in this application refers to two or more (including two).

[0099] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0100] The battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present application.

[0101] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0102] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0103] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0104] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0105] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include but are not limited to lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0106] In some embodiments, a positive electrode may be a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam, among others. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not be provided with a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled and / or deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0107] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0108] As an example, the negative electrode current collector can be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium can be used. The metal foam can be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0109] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0110] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0111] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0112] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0113] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0114] In some embodiments, the separator is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical and mechanical stability can be selected.

[0115] As an example, the primary material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component positioned between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0116] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0117] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not specifically limit the type of electrolyte, and the electrolyte can be selected based on needs. The electrolyte can be liquid, gel, or solid.

[0118] The liquid electrolyte includes an electrolyte salt and a solvent.

[0119] In some embodiments, the electrolyte salt may be selected from 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 difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0120] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent can also be an ether solvent. Ether solvents can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0121] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0122] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0123] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, or the like.

[0124] As an example, the inorganic solid electrolyte can be an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0125] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0126] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0127] In some embodiments, the electrode assembly is a laminate structure.

[0128] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0129] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0130] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0131] As an example, a plurality of separators may be provided, each of which is disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0132] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0133] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0134] In some embodiments, the electrode assembly has tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0135] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0136] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, and a polygonal battery. The polygonal battery is, for example, a hexagonal battery, etc. There is no special limitation in this application.

[0137] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0138] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0139] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0140] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0141] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0142] In a battery cell, the outer shell may include a housing and an end cap, wherein the housing has an opening and the end cap closes the opening of the housing. As an important component of a battery cell, the difficulty of molding the housing directly affects the production cost of the battery cell.

[0143] The housing is typically formed from a base material through stamping or stretching. During the forming process, the base material is subjected to significant forces, making it prone to breakage. This makes the housing difficult to form and results in a low yield rate. This is especially true when thinning the housing to increase the energy density of battery cells is crucial. Forming thin-walled housings through stamping or stretching is particularly challenging, making it difficult to achieve.

[0144] In view of this, an embodiment of the present application provides a shell, which is formed by bending a plate, and the head and tail ends of the plate are connected to each other to enclose a receiving space with openings at opposite ends, and the receiving space is used to accommodate the electrode assembly of the battery cell.

[0145] In such a shell, the shell is formed by bending a plate, and the head and tail end walls of the plate are connected to each other to form a shell with openings at opposite ends. The shell forming method is simple, which effectively reduces the difficulty of forming the shell.

[0146] The housing described in the embodiments of the present application is applicable to battery cells, batteries, and electrical equipment using battery cells.

[0147] Electrical equipment can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and electric tools, etc. Vehicles can be fuel vehicles, gas vehicles, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical equipment.

[0148] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0149] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of the present application. A battery 100 is disposed within vehicle 1000. Battery 100 can be located at the bottom, front, or rear of vehicle 1000. Battery 100 can be used to power vehicle 1000, for example, as an operating power source for vehicle 1000.

[0150] The vehicle 1000 may further include a controller 200 and a motor 300 . The controller 200 is used to control the battery 100 to supply power to the motor 300 , for example, to meet the power requirements of the vehicle 1000 during startup, navigation, and driving.

[0151] In some embodiments of the present application, the battery 100 can not only serve as the operating power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0152] Please refer to Figure 2, which is an exploded view of a battery 100 provided in some embodiments of the present application. The battery 100 may include a battery cell 10 and a housing 20, wherein the housing 20 is used to accommodate the battery cell 10.

[0153] The housing 20 is a component that houses the battery cells 10 and provides a storage space for the battery cells 10. The housing 20 can have various structures. In some embodiments, the housing 20 can include a first portion 201 and a second portion 202, which overlap to define a storage space for the battery cells 10. The first portion 201 and the second portion 202 can have various shapes, such as a rectangular parallelepiped or a cylinder. The first portion 201 can be a hollow structure with one side open, and the second portion 202 can also be a hollow structure with one side open. The open side of the second portion 202 overlaps the open side of the first portion 201, forming the housing 20 with a storage space. Alternatively, the first portion 201 can be a hollow structure with one side open, and the second portion 202 can be a plate-like structure. The second portion 202 overlaps the open side of the first portion 201, forming the housing 20 with a storage space.

[0154] In the battery 100, there can be one or more battery cells 10. If there are multiple battery cells 10, the multiple battery cells 10 can be connected in series, parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 10. Multiple battery cells 10 can be connected in series, parallel, or in a hybrid connection to form a battery module, which can then be connected in series, parallel, or in a hybrid connection to form a single unit and housed within the housing 20. Alternatively, all battery cells 10 can be directly connected in series, parallel, or in a hybrid connection, and then the entire unit formed by all battery cells 10 can be housed within the housing 20.

[0155] 3-5 , FIG3 is an assembly diagram of a battery cell 10 according to some embodiments of the present application; FIG4 is an exploded view of the battery cell 10 shown in FIG3 ; and FIG5 is a partial cross-sectional view of the battery cell 10 shown in FIG3 . The battery cell 10 may include a housing 1 and an electrode assembly 2 .

[0156] The housing 1 is a component for accommodating the electrode assembly 2 and electrolyte, etc. As an example, the housing 1 may include a shell 11 and an end cap 12 .

[0157] The housing 11 may also be a hollow structure with openings formed at opposite ends. The housing 11 may be made of a variety of materials, including metal materials such as copper, iron, aluminum, steel, and aluminum alloys, or non-metallic materials such as plastic.

[0158] The end cap 12 is a component that closes the opening of the shell 11 to isolate the internal environment of the battery cell 10 from the external environment. The end cap 12 and the shell 11 together define a storage space for accommodating the electrode assembly 2, electrolyte and other components. The end cap 12 can be connected to the shell 11 by welding or rolling to close the opening of the shell 11. The shape of the end cap 12 can be adapted to the shape of the shell 1. For example, the shell 11 is a rectangular parallelepiped structure, and the end cap 12 is a rectangular plate structure adapted to the shell 1. For another example, the shell 11 is a cylindrical structure, and the end cap 12 is a circular plate structure adapted to the shell 11. The material of the end cap 12 can also be various. The end cap 12 can be a metal material, such as copper, iron, aluminum, steel, aluminum alloy, etc. The end cap 12 can also be a non-metallic material, such as plastic. The material of the end cap 12 and the shell 11 can be the same or different. Two end covers 12 may be provided. The two end covers 12 respectively close the two openings of the shell 11 . The two end covers 12 and the shell 11 together define a receiving space.

[0159] In some embodiments, the battery cell 10 may further include an electrode terminal 3, which is disposed on the outer casing 1. The electrode terminal 3 is used to electrically connect to the tab 21 of the electrode assembly 2 to output electrical energy from the battery cell 10. The electrode terminal 3 may be disposed on the shell 11 of the outer casing 1 or on the end cap 12 of the outer casing 1. The electrode terminal 3 and the tab 21 may be directly connected, for example, by direct welding the electrode terminal 3 and the tab 21. The electrode terminal 3 and the tab 21 may also be indirectly connected, for example, by indirectly connecting the electrode terminal 3 and the tab 21 through a current collecting member. The current collecting member may be a metal conductor, such as copper, iron, aluminum, steel, or an aluminum alloy.

[0160] As an example, as shown in Figures 3 to 5, electrode terminals 3 are provided on the end covers 12 at both ends of the shell 11, and pole ears 21 are formed at the opposite ends of the electrode assembly 2. The pole ear 21 at one end of the electrode assembly 2 is a positive pole ear, and the pole ear 21 at the other end of the electrode assembly 2 is a negative pole ear. The electrode terminal 3 on one end cover 12 is electrically connected to the positive pole ear, and the electrode terminal 3 on the other end cover 12 is electrically connected to the negative pole ear.

[0161] 4 and 5 , in some embodiments, the battery cell 10 may further include a first insulating member 4, which surrounds the electrode assembly 2 and is used to insulate and isolate the electrode assembly 2 from the housing 11. The first insulating member 4 is made of an insulating material, such as plastic, rubber, etc.

[0162] In some embodiments, the battery cell 10 may further include a second insulating member 5. The second insulating member 5 is disposed corresponding to the end cap 12 and is disposed on the side of the end cap 12 facing the electrode assembly 2. The second insulating member 5 is used to insulate and separate the end cap 12 from the electrode assembly 2. The second insulating member 5 is made of an insulating material, such as plastic, rubber, etc.

[0163] Please refer to Figure 6, which is a schematic diagram of the structure of a housing 11 provided in some embodiments of the present application. Embodiments of the present application provide a housing 11 for a battery cell 10. The housing 11 is formed by bending a sheet of material. The sheet of material has two ends 112 connected to each other to enclose a receiving space 111 with openings at opposite ends. The receiving space 111 is used to accommodate the electrode assembly 2 of the battery cell 10.

[0164] The housing 11 may be cylindrical, prism-shaped, or similar. It is formed by bending a sheet material. Before forming the housing 11, the sheet material may be a rectangular plate, which can be bent to form a cylindrical or prism-shaped housing. The prism may be a triangular prism, a quadrangular prism, a pentagonal prism, a hexagonal prism, or similar. For example, as shown in FIG6 , the housing 11 is a rectangular parallelepiped.

[0165] The accommodation space 111 is a space within the housing 11 for accommodating the electrode assembly 2. The accommodation space 111 has openings at opposite ends. It is understood that the housing 11 has openings at opposite ends, and the housing 11 is a hollow structure with openings at opposite ends. The openings at the two ends of the housing 11 are arranged opposite each other along the first direction X.

[0166] Please refer to Figure 7, which is a schematic diagram of the structure of the shell 11 provided in an embodiment of the present application before molding. Before the shell 11 is molded, the plate has two opposite end faces, namely a first end face 1121 and a second end face 1122. The portion of the plate that is offset from the first end face 1121 in the direction close to the second end face 1122 within the area of ​​the first preset distance R1 is one end 112 of the plate, and the length of the end 112 is equal to the first preset distance R1; the portion of the plate that is offset from the second end face 1122 in the direction close to the first end face 1121 within the range of the second preset distance R2 is the other end 112 of the plate, and the length of the end 112 is equal to the second preset distance R2. The first preset distance R1 and the second preset distance R2 may be equal or different.

[0167] There are many ways to connect the two ends 112 of the plate, such as welding, bonding, hot melt connection, etc. In the embodiment where the housing 11 is a prism, the connection point 114 of the two ends 112 can be located on a wall portion 113 of the housing 11, or at the intersection of two walls 113, which is a corner position of the housing 11.

[0168] In the embodiment of the present application, the housing 11 is formed by bending a sheet of material. The first and second end walls of the sheet are connected together to form the housing 11 having openings at opposite ends. The simple molding method of the housing 11 effectively reduces the difficulty of molding the housing 11. During the molding process, the housing 11 is less susceptible to large impact forces, which can cause damage to the housing 11, thereby improving the molding efficiency of the housing 11.

[0169] In particular, the advantages of forming thin-walled shells are more prominent, which can effectively reduce the difficulty of forming thin-walled shells and improve the forming efficiency of thin-walled shells.

[0170] In some embodiments, please refer to Figure 8, which is a schematic diagram of the structure of the housing 11 provided in other embodiments of the present application. The housing 11 includes multiple walls 113, which enclose a receiving space 111. The housing 11 is provided with a pressure relief mechanism 13, and the connection point 114 of the two ends 112 and the pressure relief mechanism 13 are located on two different walls 113.

[0171] The walls 113 may be two, three, four, five, six, or more. If there are two walls 113, for example, one wall 113 may be a straight wall and the other wall 113 may be an arcuate wall. The cross-section of the housing 11 formed by the two walls 113 is semicircular, and the cross-section is perpendicular to the first direction X. If there are three walls 113, the housing 11 may be a triangular prism; if there are four walls 113, the housing 11 may be a quadrangular prism; if there are five walls 113, the housing 11 may be a pentagonal prism; and if there are six walls 113, the housing 11 may be a hexagonal prism.

[0172] The wall portion 113 where the pressure relief mechanism 13 is located and the wall portion 113 where the connection position 114 is located can be two adjacent wall portions 113, or they can be connected through another wall portion 113. The pressure relief mechanism 13 and the housing 11 can be an integrated structure or a separate structure.

[0173] In this embodiment, the connection position 114 and the pressure relief mechanism 13 are not arranged on the same wall portion 113, which reduces the influence of the connection position 114 on the pressure relief mechanism 13 and improves the reliability of the pressure relief mechanism 13, so that the pressure relief mechanism 13 can normally relieve pressure when the battery cell 10 thermally runs away.

[0174] In other embodiments, the connection position 114 and the pressure relief mechanism 13 may also be provided on the same wall portion 113 .

[0175] In some embodiments, please continue to refer to Figure 9, which is a cross-sectional view of the housing 11 shown in Figure 8. The multiple walls 113 include a first wall 1131 and a second wall 1132 disposed opposite each other. The pressure relief mechanism 13 is located on the first wall 1131, and the connection position 114 is located on the second wall 1132.

[0176] The first wall portion 1131 and the second wall portion 1132 are two opposite wall portions 113 of the shell 11. The pressure relief mechanism 13 and the connection position 114 are respectively located on the two opposite wall portions 113, so that the pressure relief mechanism 13 and the connection position 114 are farther apart in the circumferential direction of the shell 11, further reducing the influence of the connection position 114 on the pressure relief mechanism 13.

[0177] In some embodiments, referring to FIG. 9 , the second wall portion 1132 includes a first connecting wall 11321 and a second connecting wall 11322 disposed opposite to the first wall portion 1131 . The first connecting wall 11321 and the second connecting wall 11322 respectively form two end portions 112 .

[0178] The second wall portion 1132 can be divided into two parts, namely a first connecting wall 11321 and a second connecting wall 11322. The first connecting wall 11321 serves as one end 112 of the plate, and the second connecting wall 11322 serves as the other end 112 of the plate. The first connecting wall 11321 and the second connecting wall 11322 are connected to each other, thereby connecting the first and second ends 112 of the plate. The structure is simple and the two ends 112 of the plate can be easily connected.

[0179] In some embodiments, please refer to FIG10 , which is a partial enlarged view of the housing 11 shown in FIG9 at position C. The first connecting wall 11321 has a first end surface 1121, and the second connecting wall 11322 has a second end surface 1122. The first end surface 1121 and the second end surface 1122 are the end surfaces of the plate at the beginning and the end, respectively, and the first end surface 1121 is connected to the second end surface 1122.

[0180] It can be understood that the first end surface 1121 and the second end surface 1122 are end surfaces of the two ends 112 of the plate respectively.

[0181] The connection between the first end surface 1121 and the second end surface 1122 forms a connection point 114 where the two ends 112 of the plate are connected. The first end surface 1121 and the second end surface 1122 can be flat or curved. The curved surface can be an arcuate surface, a serrated surface, etc. The first end surface 1121 and the second end surface 1122 can be welded, bonded, or thermally melted.

[0182] As an example, the first end surface 1121 is connected to the second end surface 1122 by welding. During welding, the welding can be performed along a weld formed between the first end surface 1121 and the second end surface 1122.

[0183] In this embodiment, the first end face 1121 of the first connecting wall 11321 is connected to the second end face 1122 of the second connecting wall 11322. On the one hand, it can reduce the length of the plate, save materials, and reduce production costs; on the other hand, it makes the second connecting wall 11322 smoother as a whole, which can increase the internal space of the shell 11, which is beneficial to improving the energy density of the battery cell 10.

[0184] In some embodiments, referring to Figures 11 and 12 , Figure 11 is a cross-sectional view of a housing 11 provided in yet other embodiments of the present application; Figure 12 is a partially enlarged view of the housing 11 shown in Figure 11 at point F. Along the thickness direction of the first wall portion 1131 , the first connecting wall 11321 and the second connecting wall 11322 are at least partially stacked and connected to each other.

[0185] The first wall portion 1131 and the second wall portion 1132 are arranged opposite each other along the second direction Y. The thickness direction of the first wall portion 1131 can be consistent with the thickness direction of the first wall portion 1131. The first connecting wall 11321 and the second connecting wall 11322 can be completely or partially overlapped along the thickness direction of the first wall portion 1131. It is understood that along the thickness direction of the first wall portion 1131, the projection of the first connecting wall 11321 and the projection of the second connecting wall 11322 at least partially overlap.

[0186] Along the thickness direction of the first wall portion 1131, the first connecting wall 11321 has a first surface 11323 facing the second connecting wall 11322. The second connecting wall 11322 has a second surface 11324 facing the first connecting wall 11321. The first surface 11323 and the second surface 11324 are connected. The junction between the first surface 11323 and the second surface 11324 forms a connection point 114 where the two ends 112 of the plate are connected. The first surface 11323 and the second surface 11324 can be welded, bonded, or heat-soldered. As an example, the first surface 11323 and the second surface 11324 are welded.

[0187] As an example, as shown in Figures 11 and 12, the first connecting wall 11321 is partially stacked with the second connecting wall 11322. The first connecting wall 11321 includes a first connecting portion 11325, a second connecting portion 11326, and a third connecting portion 11327, which are sequentially connected to form a Z-shaped structure. The third connecting portion 11327 is at least partially stacked with the second connecting wall 11322, with the surface of the third connecting portion 11327 facing the second connecting wall 11322 being the first surface 11323. As an example, the third connecting portion 11327 is located on the side of the second connecting wall 11322 facing the first wall portion 1131. In other embodiments, the third connecting portion 11327 may also be located on the side of the second connecting wall 11322 facing away from the first wall portion 1131.

[0188] In this embodiment, the first connecting wall 11321 and the second connecting wall 11322 are at least partially stacked and connected to each other, which can reduce the difficulty of connecting the first connecting wall 11321 and the second connecting wall 11322, increase the connection area between the first connecting wall 11321 and the second connecting wall 11322, and improve the connection strength between the first connecting wall 11321 and the second connecting wall 11322.

[0189] In some embodiments, please continue to refer to Figures 9-12. The shell 11 also includes a third wall portion 1133 and a fourth wall portion 1134 arranged opposite to each other. The third wall portion 1133 connects the first wall portion 1131 and the first connecting wall 11321, and the fourth wall portion 1134 connects the first wall portion 1131 and the second connecting wall 11322.

[0190] The third wall portion 1133 is the wall portion 113 in the housing 11 that connects the first wall portion 1131 and the first connecting wall 11321. The fourth wall portion 1134 is the wall portion 113 in the housing 11 that connects the first wall portion 1131 and the second connecting wall 11322. It can be understood that in the housing 11, the first connecting wall 11321, the third wall portion 1133, the first wall portion 1131, the fourth wall portion 1134, and the second connecting wall 11322 are connected in sequence.

[0191] As an example, the first wall portion 1131 and the second wall portion 1132 are arranged opposite to each other along the second direction Y, and the third wall portion 1133 and the fourth wall portion 1134 are arranged opposite to each other along the third direction Z. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other.

[0192] In the embodiment shown in FIG. 11 and FIG. 12 , the first connection portion 11325 of the first connection wall 11321 is connected to the third wall portion 1133 .

[0193] In this embodiment, the housing 11 formed by the first wall portion 1131 , the second wall portion 1132 , the third wall portion 1133 and the fourth wall portion 1134 is substantially in a quadrangular prism structure, which is simple in structure and easy to form.

[0194] In some embodiments, referring to FIG. 9 to FIG. 12 , the maximum distance between the third wall portion 1133 and the fourth wall portion 1134 is A, the minimum distance between the first wall portion 1131 and the second wall portion 1132 is B, and A<B.

[0195] Along the third direction Z, the minimum distance between the inner surface of the third wall portion 1133 and the inner surface of the fourth wall portion 1134 is the maximum distance A between the third wall portion 1133 and the fourth wall portion 1134. As an example, the inner surface of the third wall portion 1133 is parallel to the inner surface of the fourth wall portion 1134.

[0196] In the embodiments shown in Figures 9 and 10, along the second direction Y, the inner surface of the first connecting wall 11321 is flush with the inner surface of the second connecting wall 11322, and the inner surface of the first connecting wall 11321 and the inner surface of the second connecting wall 11322 are both parallel to the inner surface of the first wall portion 1131 (first inner surface 11312), and the distance between the inner surface of the first connecting wall 11321 or the inner surface of the second connecting wall 11322 and the inner surface of the first wall portion 1131 (first inner surface 11312) is the minimum distance B between the first wall portion 1131 and the second wall portion 1132. In the embodiments shown in Figures 11 and 12, along the second direction Y, the inner surface of the first connecting portion 11325 is flush with the inner surface of the second connecting wall 11322, the third connecting portion 11327 is located on the side of the second connecting wall 11322 facing the first wall portion 1131, the inner surface of the third connecting portion 11327 is the surface of the first connecting wall 11321 closest to the first wall portion 1131, the inner surface of the third connecting portion 11327 is parallel to the inner surface of the first wall portion 1131 (first inner surface 11312), and the distance between the inner surface of the third connecting portion 11327 and the inner surface of the first wall portion 1131 (first inner surface 11312) is the minimum distance B between the first wall portion 1131 and the second wall portion 1132.

[0197] In this embodiment, A<B makes the pressure relief mechanism 13 and the connection position 114 respectively located on two walls 113 (the first wall 1131 and the second wall 1132) that are farther apart, further reducing the influence of the connection position 114 on the pressure relief mechanism 13. In addition, since A<B, when the electrode assembly 2 expands, the first wall 1131 and the second wall 1132 are less affected by the electrode assembly 2 than the third wall 1133 and the fourth wall 1134. Since the pressure relief mechanism 13 is located on the first wall 1131, the expansion of the electrode assembly 2 is not likely to block the pressure relief mechanism 13, reducing the risk that the expansion of the electrode assembly 2 blocks the pressure relief mechanism 13, resulting in the pressure relief mechanism 13 being unable to release pressure normally; since the connection position 114 is located on the second wall 1132, the risk of the shell 11 being damaged at the connection position 114 due to the expansion of the electrode assembly 2 is reduced.

[0198] In some embodiments, please refer to Figures 13 and 14. Figure 13 is a cross-sectional view of the housing 11 provided in some embodiments of the present application; Figure 14 is a partial enlarged view of the housing 11 shown in Figure 13 at point I. The multiple walls 113 include a first wall 1131. The pressure relief mechanism 13 is provided separately from the housing 11 and is mounted on the first wall 1131.

[0199] The first wall portion 1131 can be any one of the multiple walls 113 of the housing 11, and the pressure relief mechanism 13 is located on this wall portion 113. The connection point 114 between the two ends 112 of the plate can be located on the first wall portion 1131 or on another wall portion 113 of the housing 11. For example, as shown in FIG13 , the connection point 114 is located on the second wall portion 1132 opposite the first wall portion 1131.

[0200] The pressure relief mechanism 13 and the shell 11 are two separate components, which are separately molded and then installed together. The pressure relief mechanism 13 can be an explosion-proof valve, an explosion-proof plate or other components. The pressure relief mechanism 13 can be installed on the first wall portion 1131 by bonding, welding, screwing or the like. The first wall portion 1131 is provided with a pressure relief hole 11311, and the pressure relief mechanism 13 is installed in the pressure relief hole 11311. When the pressure inside the battery cell 10 reaches a preset value, the pressure relief mechanism 13 opens at least part of the pressure relief hole 11311, and the emissions inside the battery cell 10 are discharged through the pressure relief hole 11311 to release the pressure inside the battery cell 10. The pressure relief mechanism 13 on the first wall portion 1131 can be one or more.

[0201] As shown in Figure 14 , taking the pressure relief mechanism 13 as an explosion-proof disc as an example, the explosion-proof disc is a sheet having at least a portion of its strength less than that of the first wall portion 1131. The explosion-proof disc covers the pressure relief hole 11311 and is welded to the first wall portion 1131. When the internal pressure of the battery cell 10 reaches a threshold, the explosion-proof disc is destroyed, thereby opening at least a portion of the pressure relief hole 11311 to release the pressure within the battery cell 10.

[0202] In this embodiment, the pressure relief mechanism 13 is a component independent of the housing 11 . The pressure relief mechanism 13 and the housing 11 can be produced and reassembled separately, which increases production efficiency.

[0203] In some embodiments, referring to Figures 15-17 , Figure 15 is a partially enlarged view of the housing 11 provided in some embodiments of the present application; Figure 16 is a partially enlarged view of the housing 11 provided in other embodiments of the present application; and Figure 17 is a partially enlarged view of the housing 11 provided in yet other embodiments of the present application. The plurality of walls 113 include a first wall 1131 , with the pressure relief mechanism 13 integrally formed with the first wall 1131 .

[0204] The first wall portion 1131 can be any one of the multiple walls 113 of the housing 11, and the pressure relief mechanism 13 is located on this wall portion 113. The connection point 114 between the two ends 112 of the plate can be located on the first wall portion 1131 or on another wall portion 113 of the housing 11. For example, as shown in FIG13 , the connection point 114 is located on the second wall portion 1132 opposite the first wall portion 1131.

[0205] An integrated pressure relief mechanism 13 can be formed by weakening a local area of ​​the wall portion 113. For example, a local area of ​​the first wall portion 1131 can be annealed to make the strength of this area weaker than that of other areas of the first wall portion 1131. The annealed area of ​​the first wall portion 1131 becomes the pressure relief mechanism 13, thereby achieving an integrated formation of the pressure relief mechanism 13 and the first wall portion 1131. Another example is that a local area of ​​the first wall portion 1131 can be thinned to make the strength of this area weaker than that of other areas of the first wall portion 1131. The thinned area of ​​the first wall portion 1131 becomes the pressure relief mechanism 13, thereby achieving an integrated formation of the pressure relief mechanism 13 and the first wall portion 1131. The pressure relief mechanism 13 on the first wall portion 1131 can be one or more.

[0206] In this embodiment, the pressure relief mechanism 13 has higher reliability, and the connection process between the pressure relief mechanism 13 and the first wall portion 1131 is omitted, which can reduce the production cost of the housing 11 .

[0207] In some embodiments, please continue to refer to FIG. 15 to FIG. 17 , the first wall portion 1131 is provided with a notched groove 14 , and the first wall portion 1131 forms a pressure relief mechanism 13 corresponding to the area where the notched groove 14 is provided.

[0208] After the notch 14 is provided on the first wall portion 1131, the thickness of the first wall portion 1131 in the area where the notch 14 is provided is reduced to form a weak zone. The remaining portion of the first wall portion 1131 in the area where the notch 14 is provided is the weak zone, which serves as the pressure relief mechanism 13. When the internal pressure of the battery cell 10 reaches a threshold, the pressure relief mechanism 13 (the weak zone) is destroyed, releasing the pressure within the battery cell 10. When the pressure in the battery cell 10 is released, the pressure relief mechanism 13 can be destroyed by cracking, detaching, or other means.

[0209] The notched groove 14 can be formed in a variety of ways, such as stamping, laser etching, milling, etc. The depth direction of the notched groove 14 can be consistent with the thickness direction of the first wall portion 1131. The notched groove 14 can be a groove of various shapes, such as a linear groove, a circular groove, an elliptical groove, an annular groove, an arc-shaped groove, a U-shaped groove, an H-shaped groove, etc. Among them, a circular groove refers to a groove with a circular cross-section, and an elliptical groove refers to a groove with an elliptical cross-section, and the cross-section is perpendicular to the thickness direction of the first wall portion 1131. As an example, in Figures 15 to 17, the notched groove 14 is an annular groove.

[0210] When forming the notched groove 14 , the notched groove 14 may be formed on the plate first, and then the plate is bent to form the housing 11 ; or the plate may be bent to form the housing 11 first, and then the notched groove 14 may be formed on the housing 11 .

[0211] In this embodiment, the integrated pressure relief mechanism 13 is formed by providing the notched groove 14 on the first wall portion 1131 . The pressure relief mechanism 13 is simple to form and has low production cost.

[0212] In some embodiments, referring to FIG. 15 , the first wall portion 1131 has a first inner surface 11312 facing the interior of the housing 11 , and the notched groove 14 is disposed on the first inner surface 11312 .

[0213] The first wall portion 1131 further includes a first outer surface 11313 facing away from the interior of the housing 11. Along the thickness direction of the first wall portion 1131, the first outer surface 11313 is disposed opposite the first inner surface 11312. The first outer surface 11313 is not provided with the notched groove 14. The portion between the bottom of the notched groove 14 and the first outer surface 11313 forms the pressure relief mechanism 13. For example, the first outer surface 11313 is parallel to the first inner surface 11312, and the distance between the first outer surface 11313 and the first inner surface 11312 is the thickness of the first wall portion 1131.

[0214] In the embodiment where the first wall portion 1131 and the second wall portion 1132 are arranged opposite to each other along the first direction X, along the first direction X, the first inner surface 11312 faces the second wall portion 1132 , and the first outer surface 11313 faces away from the second wall portion 1132 .

[0215] In this embodiment, the notched groove 14 is provided with a first inner surface 11312. On the one hand, when the notched groove 14 is formed on the first inner surface 11312 of the first wall portion 1131, it is not easy to affect the outer surface of the first wall portion 1131, so that the outer surface of the first wall portion 1131 remains flat; on the other hand, the notched groove 14 is provided on the first inner surface 11312 of the first wall portion 1131, and the groove wall surface of the notched groove 14 is not exposed to the outside of the battery cell 10, thereby reducing the risk of the first wall portion 1131 being oxidized in the area where the notched groove 14 is provided, thereby improving the stability of the integrated pressure relief mechanism 13.

[0216] In some embodiments, referring to FIG. 16 , the first wall portion 1131 has a first outer surface 11313 facing away from the interior of the housing 11 , and the notched groove 14 is disposed on the first outer surface 11313 .

[0217] The first wall portion 1131 further has a first inner surface 11312 facing the interior of the housing 11. Along the thickness direction of the first wall portion 1131, the first inner surface 11312 is disposed opposite the first outer surface 11313. The first inner surface 11312 is not provided with the notched groove 14. The portion between the bottom of the notched groove 14 and the first inner surface 11312 forms the pressure relief mechanism 13. For example, the first outer surface 11313 is parallel to the first inner surface 11312, and the distance between the first outer surface 11313 and the first inner surface 11312 is the thickness of the first wall portion 1131.

[0218] In this embodiment, the notched groove 14 is arranged on the first outer surface 11313. When the notched groove 14 is formed on the first outer surface 11313 of the first wall portion 1131, it is not easy to affect the inner surface of the first wall portion 1131, so that the inner surface of the first wall portion 1131 remains flat.

[0219] In some embodiments, referring to FIG. 17 , the first wall portion 1131 has a first inner surface 11312 facing the interior of the shell 11 and a first outer surface 11313 facing away from the interior of the shell 11 . Both the first inner surface 11312 and the first outer surface 11313 are provided with notched grooves 14 .

[0220] Along the thickness direction of the first wall portion 1131, the first inner surface 11312 and the first outer surface 11313 are disposed opposite each other, and both the first inner surface 11312 and the first outer surface 11313 are provided with the notched groove 14. As an example, the first outer surface 11313 is parallel to the first inner surface 11312, and the distance between the first outer surface 11313 and the first inner surface 11312 is the thickness of the first wall portion 1131.

[0221] During molding, the notched groove 14 located on the first inner surface 11312 can be molded from the inside of the shell 11 , and the notched groove 14 located on the first outer surface 11313 can be molded from the outside of the shell 11 .

[0222] In some embodiments, the notched groove 14 disposed on the first outer surface 11313 is disposed opposite to the notched groove 14 disposed on the first inner surface 11312 .

[0223] Along the thickness direction of the first wall portion 1131, the projection of the bottom surface of the scored groove 14 provided on the first outer surface 11313 overlaps with the projection of the bottom surface of the scored groove 14 provided on the first inner surface 11312, thereby achieving an opposing arrangement of the scored groove 14 provided on the first outer surface 11313 and the scored groove 14 provided on the first inner surface 11312. The extending direction of the scored groove 14 provided on the first outer surface 11313 and the extending direction of the scored groove 14 provided on the first inner surface 11312 may be the same or different.

[0224] As an example, in FIG17 , the scoring groove 14 on the first outer surface 11313 extends in the same direction as the scoring groove 14 on the first inner surface 11312, both extending along an annular trajectory. Along the thickness direction of the first wall portion 1131, the projection of the bottom surface of the scoring groove 14 on the first outer surface 11313 completely overlaps with the projection of the bottom surface of the scoring groove 14 on the first inner surface 11312. The portion between the bottom surfaces of the scoring groove 14 on the first outer surface 11313 and the bottom surfaces of the scoring groove 14 on the first inner surface 11312 forms the pressure relief mechanism 13. It will be appreciated that the scoring groove 14 on the first outer surface 11313 and the scoring groove 14 on the first inner surface 11312 correspond to the same pressure relief mechanism 13.

[0225] In this embodiment, the notched groove 14 provided on the first outer surface 11313 is arranged opposite to the notched groove 14 provided on the first inner surface 11312. When the thickness of the first wall portion 1131 and the thickness of the pressure relief mechanism 13 are constant, the processing depth of the notched groove 14 on the first inner surface 11312 and the first outer surface 11313 is smaller, thereby reducing the forming force applied to the first wall portion 1131 when forming the notched groove 14, and reducing the risk of cracks in the first wall portion 1131.

[0226] In other embodiments, the scored grooves 14 on the first outer surface 11313 are offset from the scored grooves 14 on the first inner surface 11312. That is, along the thickness direction of the first wall portion 1131, the projection of the bottom surface of the scored grooves 14 on the first outer surface 11313 and the projection of the bottom surface of the scored grooves 14 on the first inner surface 11312 do not overlap. This creates multiple pressure relief mechanisms 13 on the first wall portion 1131, improving the reliability of the battery cell 10.

[0227] In some embodiments, please refer to Figures 18 and 19. Figure 18 is a partial enlarged view of the housing 11 (with protrusions 15 provided on the first inner surface 11312) provided in some embodiments of the present application; Figure 19 is a partial enlarged view of the housing 11 (with protrusions 15 provided on both the first inner surface 11312 and the first outer surface 11313) provided in some embodiments of the present application. The first wall portion 1131 has a protrusion 15 formed at the edge of the scored groove 14, protruding from the first inner surface 11312.

[0228] The protrusion 15 protruding from the first inner surface 11312 corresponds to the scored groove 14 provided on the first inner surface 11312. For the scored groove 14 provided on the first inner surface 11312, the intersection of the groove side surface of the scored groove 14 and the first inner surface 11312 is the edge of the scored groove 14. The protrusion 15 protruding from the first inner surface 11312 can extend in the same direction as the scored groove 14. The protrusion 15 and the first wall portion 1131 can be integrally formed, or they can be separately provided and connected, for example, by welding.

[0229] As an example, the notch groove 14 can be stamped and formed on the first inner surface 11312. During the stamping process of the notch groove 14, material accumulates outside the notch groove 14, and a protrusion 15 protruding from the first inner surface 11312 can be formed accordingly.

[0230] In this embodiment, the protrusion 15 protruding from the first inner surface 11312 strengthens the area of ​​the first wall portion 1131 where the notched groove 14 is provided, thereby strengthening the pressure relief mechanism 13, improving the fatigue resistance of the pressure relief mechanism 13, and reducing the risk of the first wall portion 1131 of the battery cell 10 being damaged due to fatigue of the pressure relief mechanism 13 under normal use conditions.

[0231] In some embodiments, please refer to Figures 19 and 20. Figure 20 is a partially enlarged view of the housing 11 (with the protrusion 15 provided on the first outer surface 11313) provided in some embodiments of the present application. The first wall portion 1131 has a protrusion 15 formed at the edge of the scored groove 14, protruding from the first outer surface 11313.

[0232] The protrusion 15 protruding from the first outer surface 11313 corresponds to the scored groove 14 provided on the first outer surface 11313. For the scored groove 14 provided on the first outer surface 11313, the intersection of the groove side surface of the scored groove 14 and the first outer surface 11313 is the edge of the scored groove 14. The protrusion 15 protruding from the first outer surface 11313 can extend in the same direction as the scored groove 14. The protrusion 15 and the first wall portion 1131 can be integrally formed, or they can be separately provided and connected, for example, by welding.

[0233] As an example, the notch groove 14 can be stamped and formed on the first outer surface 11313. During the stamping process of the notch groove 14, material accumulates outside the notch groove 14, and a protrusion 15 protruding from the first outer surface 11313 can be formed accordingly.

[0234] In this embodiment, the protrusion 15 protruding from the first outer surface 11313 strengthens the area of ​​the first wall portion 1131 where the notched groove 14 is provided, thereby strengthening the pressure relief mechanism 13, improving the fatigue resistance of the pressure relief mechanism 13, and reducing the risk of the first wall portion 1131 of the battery cell 10 being damaged due to fatigue of the pressure relief mechanism 13 under normal use conditions.

[0235] In some embodiments, please continue to refer to Figures 15 to 20. Along the thickness direction of the first wall portion 1131, the thickness of the first wall portion 1131 is D, the residual thickness of the area of ​​the first wall portion 1131 where the notch groove 14 is set is H1, and H1 / D≤0.7.

[0236] H1 / D can be any point value among 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, etc., or a range of values ​​between any two points.

[0237] Along the thickness direction of the first wall portion 1131, the first wall portion 1131 has a first inner surface 11312 and a first outer surface 11313 that are opposite to each other. The minimum distance between the first inner surface 11312 and the first outer surface 11313 is the thickness D of the first wall portion 1131. As an example, the first inner surface 11312 and the first outer surface 11313 are arranged parallel to each other, and the distance between the first inner surface 11312 and the first outer surface 11313 is the thickness D of the first wall portion 1131.

[0238] The thickness of the pressure relief mechanism 13 is the residual thickness H1 of the region of the first wall portion 1131 where the scored groove 14 is provided. In the embodiments shown in Figures 15 and 18 , the scored groove 14 is provided on the first inner surface 11312. The minimum distance between the bottom surface of the scored groove 14 and the first outer surface 11313 is the residual thickness H1 of the region of the first wall portion 1131 where the scored groove 14 is provided. In the embodiments shown in Figures 16 and 20 , the scored groove 14 is provided on the first outer surface 11313. The minimum distance between the bottom surface of the scored groove 14 and the first inner surface 11312 is the residual thickness H1 of the region of the first wall portion 1131 where the scored groove 14 is provided. In the embodiments shown in Figures 17 and 19, the first outer surface 11313 and the first inner surface 11312 are both provided with a notched groove 14, and the notched groove 14 provided on the first outer surface 11313 and the notched groove 14 provided on the first inner surface 11312 are arranged opposite to each other, and the minimum distance between the groove bottom surface of the notched groove 14 provided on the first outer surface 11313 and the groove bottom surface of the notched groove 14 provided on the first inner surface 11312 is the residual thickness H1 of the area where the notched groove 14 is provided on the first wall portion 1131.

[0239] The inventors conducted multiple experiments in which the residual thickness of the first wall portion 1131 in the area where the notched groove 14 is provided (the thickness of the pressure relief mechanism 13 ) varied across the battery cells 10 in different groups. The inventors measured the cracking rate of the weak areas in each group of battery cells 10 under normal use conditions and the explosion rate of the battery cells 10 during thermal runaway. The test results are shown in Table 1 below.

[0240] (1) Measure the crack rate of the pressure relief mechanism 13 of the battery cell 10 under normal use conditions.

[0241] The battery cells 10 were placed at 25±2°C and cycled between 5% and 97% SOC. The internal gas pressure of the battery cells 10 was monitored, and 1,000 tests were performed simultaneously. The test ended when the battery cell 10 lifespan dropped to 80% SOH or when the pressure relief mechanism 13 of any group of battery cells 10 cracked during cycling. The pressure relief mechanism 13 cracking condition was determined when the internal pressure of the battery cell 10 decreased by >10% of the maximum pressure. The pressure relief mechanism 13 cracking rate was calculated as follows: number of cracks / total number of cracks*100%.

[0242] (2) Measure the explosion rate of the battery cell 10 during thermal runaway.

[0243] A small heating film was built into each battery cell 10. The heating film was energized to heat the battery cell 10 until thermal runaway occurred. The battery cell 10 was observed to see if it exploded. This test was repeated 1,000 times, and the explosion rate of the battery cells 10 was calculated: explosion rate = number of explosions / total number of explosions * 100%.

[0244] Table 1

[0245] As shown in Table 1, when H1 / D > 0.7, the detonation pressure of the battery cell 10 is too high, making it more difficult for the pressure relief mechanism 13 to be destroyed during thermal runaway of the battery cell 10, and thus prone to delayed pressure relief. Therefore, when H1 / D ≤ 0.7, the timely pressure relief of the battery cell 10 can be effectively improved, reducing the risk of explosion caused by thermal runaway of the battery cell 10.

[0246] In some embodiments, H1 ≥ 0.05 mm.

[0247] H1 can be any point value among 0.05mm, 0.08mm, 0.1mm, 0.12mm, 0.14mm, 0.15mm, 0.16mm, 0.2mm, 0.25mm, 0.3mm, etc., or a range value between any two of them.

[0248] As shown in Table 1, when H1 is less than 0.05 mm, under normal use conditions of the battery cell 10, the first wall portion 1131 is too thin in the area where the notch 14 is located (pressure relief mechanism 13), resulting in excessive stress. This can easily shorten the life of the pressure relief mechanism 13 due to fatigue and creep, leading to premature failure of the pressure relief mechanism 13. Under normal use conditions, the pressure relief mechanism 13 of the battery cell 10 has a high cracking rate, which affects the service life of the battery cell 10. Therefore, when H1 is ≥ 0.05 mm, the risk of damage to the pressure relief mechanism 13 under normal use conditions of the battery cell 10 is reduced, thereby increasing the service life of the battery cell 10.

[0249] In some embodiments, D ≤ 0.6 mm.

[0250] D can be any point value among 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, etc., or a range of values ​​between any two of them.

[0251] In this embodiment, D≦0.6 mm, so that the first wall portion 1131 is relatively thin. When the outer dimensions of the shell 11 remain constant, the internal space of the shell 11 can be increased, which is beneficial to improving the energy density of the battery cell 10 .

[0252] In some embodiments, please refer to Figure 21, which is a schematic diagram of the structure of the first wall portion 1131 (the pressure relief groove is V-shaped) provided in some embodiments of the present application. The scored groove 14 includes a first groove section 141 and a second groove section 142, and the first groove section 141 and the second groove section 142 intersect.

[0253] The first groove section 141 and the second groove section 142 can be straight grooves or non-straight grooves, such as arc-shaped grooves. Taking the example of the first groove section 141 and the second groove section 142 being straight grooves, the first groove section 141 and the second groove section 142 both extend along a straight line. The first groove section 141 and the second groove section 142 can be arranged at an acute angle, a right angle, or an obtuse angle. The first groove section 141 and the second groove section 142 can be arranged crosswise, for example, the intersection of the first groove section 141 and the second groove section 142 is located at the midpoint of the first groove section 141 and the midpoint of the second groove section 142. As an example, as shown in FIG. 21 , the intersection of the first groove section 141 and the second groove section 142 can also be located at one end of the first groove section 141 and one end of the second groove section 142, so that the first groove section 141 and the second groove section 142 form a V-shaped structure, making the notched groove 14 a V-shaped groove. The scored groove 14 defines a pressure relief area 144, with the first groove section 141 and the second groove section 142 located at the edge of the pressure relief area 144. In the event of thermal runaway of the battery cell 10, the housing 11 can rupture along the first and second groove sections 141, 142, and the housing 11 can flip open outward from the pressure relief area 144, achieving large-scale pressure relief for the housing 11. The triangular shaded area shown in Figure 21 represents the pressure relief area 144.

[0254] The stress is more concentrated at the intersection of the first and second groove sections 141, 142, making the housing 11 more susceptible to damage at this intersection. This improves the pressure relief sensitivity of the housing 11, allowing for timely pressure relief when the internal pressure of the battery cell 10 reaches the detonation pressure. Given a constant detonation pressure for the battery cell 10, the depth of the score groove 14 can be appropriately reduced, increasing the residual thickness of the housing 11 in the area where the score groove 14 is located, thereby improving the fatigue strength of the housing 11 in this area.

[0255] In some embodiments, referring to Figures 22 and 23, Figure 22 illustrates the structure of a first wall portion 1131 (with a U-shaped pressure relief groove) provided in some embodiments of the present application; Figure 23 illustrates the structure of a first wall portion 1131 (with an H-shaped pressure relief groove) provided in some embodiments of the present application. The scored groove 14 further includes a third groove segment 143. The first groove segment 141 and the third groove segment 143 are disposed opposite each other, and the third groove segment 143 intersects with the second groove segment 142.

[0256] The first slot section 141, the second slot section 142, and the third slot section 143 can all be linear slots, or non-linear slots, such as arc-shaped slots. Taking the first slot section 141, the second slot section 142, and the third slot section 143 as linear slots as an example, the first slot section 141, the second slot section 142, and the third slot section 143 all extend along a linear trajectory, and the first slot section 141 and the third slot section 143 can be arranged in parallel. The first slot section 141 and the third slot section 143 can both be perpendicular to the second slot section 142, or they can be non-perpendicular to the second slot section 142.

[0257] In this embodiment, the shell 11 has a large pressure relief area after being split along the first groove section 141, the second groove section 142, and the third groove section 143, achieving large-area pressure relief. In addition, the intersection of the third groove section 143 and the second groove section 142 is more concentrated, making the shell 11 more easily damaged at the intersection of the second groove section 142 and the third groove section 143. This improves the pressure relief sensitivity of the shell 11 and enables timely pressure relief when the internal pressure of the battery cell 10 reaches the detonation pressure. Similarly, if the detonation pressure of the battery cell 10 is constant, the depth of the score groove 14 can be appropriately reduced, thereby increasing the residual thickness of the shell 11 in the area where the score groove 14 is provided, thereby improving the fatigue strength of the shell 11 in the area where the score groove 14 is provided.

[0258] In some embodiments, referring to FIG. 22 , the first slot segment 141 , the second slot segment 142 , and the third slot segment 143 are connected in sequence.

[0259] The first slot section 141, the second slot section 142 and the third slot section 143 are connected in sequence to form a U-shaped structure or a Z-shaped structure. As an example, in the embodiment shown in Figure 22, the first slot section 141, the second slot section 142 and the third slot section 143 are connected in sequence to form a U-shaped structure. The pressure relief groove defines a pressure relief area 144, and the first slot section 141, the second slot section 142 and the third slot section 143 are located at the edge of the pressure relief area 144. When the battery cell 10 thermally runs away, the shell 11 can be cracked along the first slot section 141, the second slot section 142 and the third slot section 143, and the shell 11 can be flipped outward from the pressure relief area 144 to achieve large-area pressure relief of the shell 11. The rectangular shaded area shown in Figure 22 is the pressure relief area 144.

[0260] In this embodiment, the first groove segment 141 , the second groove segment 142 and the third groove segment 143 are connected in sequence. Such a notched groove 14 has a simple structure and is easy to form.

[0261] In some embodiments, the first slot segment 141 and the second slot segment 142 intersect at a first position 145, which is offset from the ends of the first slot segment 141 in the extension direction. The third slot segment 143 and the second slot segment 142 intersect at a second position 155, which is offset from the ends of the third slot segment 143 in the extension direction.

[0262] The first position 145 is where the first slot segment 141 connects with the second slot segment 142. The first position 145 is offset from both ends of the first slot segment 141 in the extension direction. That is, in the extension direction of the first slot segment 141, there is a distance between the first position 145 and both ends of the first slot segment 141. The second position 155 is where the third slot segment 143 connects with the second slot segment 142. The second position 155 is offset from both ends of the third slot segment 143 in the extension direction. That is, in the extension direction of the third slot segment 143, there is a distance between the second position 155 and both ends of the third slot segment 143.

[0263] The first slot section 141, the second slot section 142 and the third slot section 143 define two pressure relief areas 144, which are located on either side of the second slot section 142. The two rectangular shaded areas shown in FIG23 are both pressure relief areas 144.

[0264] During pressure relief, the areas of the shell 11 located on both sides of the second slot section 142 (pressure relief areas 144) can be opened after the shell 11 is split along the first slot section 141, the second slot section 142 and the third slot section 143, which can effectively improve the pressure relief efficiency of the shell 11.

[0265] In some embodiments, the first position 145 is located at the midpoint of the first slot segment 141 in the extension direction, and the second position 155 is located at the midpoint of the third slot segment 143 in the extension direction.

[0266] As an example, the first slot segment 141, the second slot segment 142 and the third slot segment 143 are all straight slots extending along a straight trajectory, the first slot segment 141 and the third slot segment 143 are arranged in parallel, the first slot segment 141 and the second slot segment 142 are perpendicular, and the lengths of the first slot segment 141 and the third slot segment 143 are equal.

[0267] In this embodiment, the first position 145 and the second position 155 are located at the midpoints of the first slot section 141 and the third slot section 143 respectively. The shell 11 is more easily destroyed at the first position 145 and the second position 155, thereby improving the pressure relief sensitivity of the shell 11 and improving the timeliness of pressure relief.

[0268] In some embodiments, the score groove 14 is a groove extending along a non-closed trajectory.

[0269] A non-closed trajectory refers to a trajectory whose ends are not connected in the extension direction. For example, the score groove 14 defines a pressure relief zone 144, and the score groove 14 is located at the edge of the pressure relief zone 144. A non-closed trajectory can be an arc-shaped trajectory, a U-shaped trajectory, or the like. If the score groove 14 extends along an arc-shaped trajectory, the score groove 14 is an arc-shaped trajectory; if the score groove 14 extends along a U-shaped trajectory, the score groove 14 is a U-shaped groove.

[0270] During the pressure relief process, the area defined by the notched groove 14 (pressure relief zone 144) can be opened in a flipping manner, and after opening, the area is eventually connected to other parts of the shell 11, reducing the risk of splashing of the open part.

[0271] In some embodiments, please refer to Figure 24, which is a schematic structural diagram of the first wall portion 1131 (the pressure relief groove is an arc-shaped groove) provided in some embodiments of the present application. The notched groove 14 is an arc-shaped groove.

[0272] A circular arc groove is a groove extending along a circular arc trajectory, which is a non-closed trajectory. The scored groove 14 defines a pressure relief zone 144, which is located at the edge of the pressure relief zone 144. The central angle of the circular arc groove can be less than, equal to, or greater than 180°. As an example, in the embodiment shown in FIG24 , the central angle of the circular arc groove is 180°. The semicircular shaded area shown in FIG24 represents the pressure relief zone 144.

[0273] The arc-shaped groove has a simple structure and is easy to form. During the pressure relief process, the housing 11 can quickly split along the arc-shaped groove, so that the area defined by the arc-shaped groove (pressure relief area 144) is quickly opened.

[0274] In some embodiments, the score groove 14 is a groove extending along a closed trajectory.

[0275] A closed track refers to a track connected at both ends, and the closed track may be a circular track, a rectangular track, an elliptical track, etc. The score groove 14 defines a pressure relief area 144 , and the score groove 14 is located at the edge of the pressure relief area 144 .

[0276] During the pressure relief process, the shell 11 can be split along the notched groove 14 so that the area defined by the notched groove 14 (pressure relief zone 144) can be opened in a detached manner, thereby increasing the pressure relief area of ​​the shell 11 and improving the pressure relief rate of the shell 11.

[0277] In some embodiments, FIG25 is a schematic structural diagram of the first wall portion 1131 (the pressure relief groove is an annular groove) provided in some embodiments of the present application, and the notched groove 14 is an annular groove.

[0278] The annular groove can be a rectangular annular groove, a circular annular groove, etc.

[0279] As an example, in FIG25 , the scored groove 14 is a generally rectangular annular groove. The scored groove 14 comprises two straight segments and two arc segments. The two straight segments are arranged in parallel, with one straight segment, one arc segment, another straight segment, and another arc segment connected end to end. The spacing between the two straight segments is less than the minimum spacing between the two arc segments.

[0280] In this embodiment, the annular groove has a simple structure and is easy to form. During the pressure relief process, the housing 11 can be quickly split along the annular groove to quickly open the area defined by the annular groove.

[0281] It should be noted that in the above-mentioned embodiments in which the pressure relief area 144 is defined by the notched groove 14, reinforcing ribs 1411 can be provided in the pressure relief area 144. The reinforcing ribs 1411 can be used to reinforce the pressure relief area 144, thereby improving the deformation resistance of the pressure relief area 144 and reducing the risk of the shell 11 being damaged at the position of the notched groove 14 due to deformation of the pressure relief area 144 caused by changes in the internal pressure of the battery cell 10, thereby improving the service life of the battery cell 10.

[0282] Please refer to Figure 26, which is a schematic diagram of the structure of the first wall portion 1131 (the pressure relief groove is an annular groove) provided in some other embodiments of the present application. Taking the pressure relief groove as an annular groove as an example, the pressure relief area 144 defined by the pressure relief area 144 can be provided with a reinforcing rib 1411. The reinforcing rib 1411 can be provided on the first inner surface 11312 (not shown in Figure 26) and / or the first outer surface 11313 (not shown in Figure 26) of the first wall portion 1131. The reinforcing rib 1411 can be linear, arc-shaped, U-shaped, C-shaped, H-shaped, annular, etc.

[0283] As an example, as shown in Figure 26, the reinforcing rib 1411 includes two arc ribs, the openings of the two arc ribs are arranged back to back, and the middle areas of the two arc ribs are connected together. This structure of the reinforcing rib 1411 can better strengthen the pressure relief area 144 and improve the deformation resistance of the pressure relief area 144.

[0284] In some embodiments, please refer to Figure 27, which is a schematic structural diagram of the housing 11 provided in yet other embodiments of the present application. The openings at both ends of the housing 11 are arranged opposite each other along the first direction X. The multiple walls 113 include a first wall 1131, and the first wall 1131 is provided with multiple pressure relief mechanisms 13, which are arranged along the first direction X.

[0285] The first wall portion 1131 can be any one of the multiple walls 113 of the housing 11, and the pressure relief mechanism 13 is located in this wall portion 113. The connection point 114 between the two ends 112 of the plate can be located in the first wall portion 1131 or in another wall portion 113 of the housing 11. As an example, in the embodiment shown in FIG27 , the connection point 114 is located in the second wall portion 1132 opposite the first wall portion 1131.

[0286] There may be two, three, four, five, or more pressure relief mechanisms 13 on the first wall portion 1131, with adjacent pressure relief mechanisms 13 spaced apart. The pressure relief mechanisms 13 and the first wall portion 1131 may be separate or integrally formed. For example, in the embodiment shown in FIG27 , the pressure relief mechanisms 13 are integrally formed with the first wall portion 1131.

[0287] In the event of thermal runaway of a battery cell 10, pressure can be released through the multiple pressure relief mechanisms 13 on the first wall 1131, improving the timeliness of pressure release and enhancing the reliability of the battery cell 10. If a portion of the pressure relief mechanisms 13 on the first wall 1131 is blocked or fails, pressure can be released through another portion of the pressure relief mechanisms 13 on the first wall 1131, thereby improving the reliability of the battery cell 10.

[0288] 27 , two pressure relief mechanisms 13 are provided on the first wall portion 1131. This allows the housing 11 to have a good pressure relief capability while reducing the production cost of the housing 11.

[0289] In some embodiments, please refer to FIG. 28 , which is a view of the housing 11 shown in FIG. 27 taken along an M-axis. The two pressure relief mechanisms 13 are respectively a first pressure relief mechanism 131 and a second pressure relief mechanism 132. Along the first direction X, the housing 11 has a first opening end 115 and a second opening end 116 opposite each other. The first pressure relief mechanism 131 is closer to the first opening end 115 than the second pressure relief mechanism 132. The distance between the first pressure relief mechanism 131 and the second pressure relief mechanism 132 is K1, the distance between the first pressure relief mechanism 131 and the first opening end 115 is K2, and the distance between the second pressure relief mechanism 132 and the second opening end 116 is K3, where K2 is less than K1 and K3 is less than K1.

[0290] The first open end 115 is an end of the housing 11 with an opening along the first direction X. The second open end 116 is an end of the housing 11 with another opening along the first direction X. The distance between the first open end 115 and the second open end 116 is the length of the housing 11 .

[0291] Along the first direction X, the distance between the end of the first pressure relief mechanism 131 facing the second pressure relief mechanism 132 and the end of the second pressure relief mechanism 132 facing the first pressure relief mechanism 131 is defined as the spacing K1 between the first and second pressure relief mechanisms 131, 132. Along the first direction X, the distance between the end of the first pressure relief mechanism 131 facing away from the second pressure relief mechanism 132 and the first open end 115 is defined as the spacing K2 between the first and second open end 115. Along the first direction X, the distance between the end of the second pressure relief mechanism 132 facing away from the first pressure relief mechanism 131 and the second open end 116 is defined as the spacing K3 between the second and second open end 116.

[0292] Among them, K1 and K2 can be equal or different.

[0293] When the battery cell 10 thermally runs away, the emissions inside the battery cell 10 are more likely to accumulate in the areas near the two ends of the shell 11. Since K2 is less than K1 and K2 is less than K1, the first pressure relief mechanism 131 is close to the first opening end 115 and the second pressure relief mechanism 132 is close to the second opening end 116, so that the emissions inside the battery cell 10 can be more easily discharged through the first pressure relief mechanism 131 and the second pressure relief mechanism 132, thereby improving the timeliness of pressure relief.

[0294] In some embodiments, K2 / K1≤0.5; and / or, K3 / K1≤0.5.

[0295] K2 / K1 can be any point value among 0.1, 0.2, 0.3, 0.4, 0.5, etc., or a range of values ​​between any two points. K3 / K1 can be any point value among 0.1, 0.2, 0.3, 0.4, 0.5, etc., or a range of values ​​between any two points.

[0296] K2 / K1≤0.5 places the first pressure relief mechanism 131 closer to the first open end 115, facilitating the discharge of internal emissions from the battery cell 10 through the first pressure relief mechanism 131 in the event of thermal runaway. K3 / K1≤0.5 places the second pressure relief mechanism 132 closer to the second open end 116, facilitating the discharge of internal emissions from the battery cell 10 through the second pressure relief mechanism 132 in the event of thermal runaway.

[0297] In some embodiments, the end surfaces of the plate are connected to each other at both ends.

[0298] For example, the plate is a rectangular plate before being formed into the housing 11. The end surfaces at the first and second ends of the plate can be two end surfaces opposite to each other in the longitudinal direction of the plate. The housing 11 formed by connecting the end surfaces at the first and second ends of the plate can have various shapes, such as a cylinder, a prism, etc.

[0299] As shown in Figure 27, in an embodiment where the second wall portion 1132 arranged opposite to the first wall portion 1131 includes a first connecting wall 11321 and a second connecting wall 11322, the first end face 1121 (not shown in Figure 27) of the first connecting wall 11321 and the second end face 1122 (not shown in Figure 27) of the second connecting wall 11322 are the end faces at the head and tail ends of the plate, respectively.

[0300] In this embodiment, the end faces at both ends of the plate are connected to each other. On the one hand, there is no overlapping part after the two ends 112 of the plate are connected, which saves materials and reduces production costs. On the other hand, the end faces at both ends of the shell 11 are connected to each other, making the shell 11 flatter, which can increase the internal space of the shell 11 and is beneficial to improving the energy density of the battery cell 10.

[0301] In some embodiments, the two ends 112 of the plate are connected by welding.

[0302] In the embodiment where the second wall portion 1132 disposed opposite to the first wall portion 1131 includes a first connecting wall 11321 and a second connecting wall 11322 , the first connecting wall 11321 and the second connecting wall 11322 are respectively two end portions 112 of the plate.

[0303] In this embodiment, the two ends 112 of the plate are connected by welding, so that the two ends 112 have good connection strength, and the two ends 112 are more firmly connected.

[0304] In some embodiments, the housing 11 includes a plurality of wall portions 113 , which enclose a receiving space 111 ; and the connection position 114 of the two ends 112 of the plate is located on one wall portion.

[0305] For example, the housing 11 includes four walls 113, which form a rectangular parallelepiped housing. The connection point 114 of the two ends 112 of the plate can be located at any one of the four walls 113. As an example, as shown in FIG27 , the connection point 114 of the two ends 112 is located at the first wall 1131.

[0306] In this embodiment, the connection positions 114 of the two ends 112 of the plate are located on a wall portion, which can reduce the difficulty of connecting the two ends 112 and improve the connection strength of the connection position 114.

[0307] In some embodiments, please refer to Figure 29, which is a partial enlarged view of the portion N of the housing 11 shown in Figure 27. The wall thickness of the housing 11 is L, where L is less than or equal to 0.6 mm.

[0308] L can be any point value among 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, etc., or a range of values ​​between any two points.

[0309] It is understood that in the embodiment where the housing 11 is enclosed by a plurality of walls 113, the thickness of each wall 113 in the housing 11 is no greater than 0.6 mm. Taking the example of a housing 11 enclosed by a first wall 1131, a second wall 1132, a third wall 1133, and a fourth wall 1134, the thickness of the first wall 1131, the thickness of the second wall 1132, the thickness of the third wall 1133, and the thickness of the fourth wall 1134 are all no greater than 0.6 mm.

[0310] In this embodiment, L≤0.6mm, and the shell 11 formed by bending a plate is a thin-walled shell, which is conducive to achieving lightweighting of the battery cell 10. When the outer dimensions of the shell 11 are certain, the thin-walled shell has a larger internal space. The thin-walled shell can provide a larger accommodating space 111 for the electrode assembly 2, which is conducive to improving the energy density of the battery cell 10.

[0311] In some embodiments, the housing 11 is a rectangular parallelepiped housing, which is suitable for rectangular parallelepiped battery cells 10 and can meet the large capacity requirements of the battery cells 10 .

[0312] In some embodiments, please refer to Figure 30, which is a schematic diagram of the structure of the housing 11 provided in some other embodiments of the present application. The openings at both ends of the housing 11 are arranged opposite each other along the length direction of the housing 11. The length of the housing 11 is a, the width of the housing 11 is b, and the height of the housing 11 is c, where b≤c≤a / 1.5.

[0313] It is understood that a / c ≥ 1.5, and a / c can be any value among 1.5, 2, 3, 4, 5, etc., or a range of values ​​between any two. b can be < c, or b = c. In the embodiment shown in FIG30 , b < c.

[0314] Taking the case 11 enclosed by a first wall 1131, a second wall 1132, a third wall 1133, and a fourth wall 1134 as an example, the openings at both ends of the case 11 are arranged opposite each other along a first direction X, the first wall 1131 and the second wall 1132 are arranged opposite each other along a second direction Y, the third wall 1133 and the fourth wall 1134 are arranged opposite each other along a third direction Z, and two adjacent walls 113 in the case 11 are perpendicular to each other. The first direction X may be the length direction of the case 11, the second direction Y may be the height direction of the case 11, and the third direction Z may be the width direction of the case 11.

[0315] In this embodiment, the housing 11 is in an elongated shape, which is beneficial for improving the energy density of the battery cell 10. In addition, since the elongated housing is formed by bending a plate, it is easier to form a thin-walled elongated housing than traditional stamping or stretching.

[0316] In some embodiments, the openings at both ends of the housing 11 are arranged opposite to each other along the length direction of the housing 11 , and the length of the housing 11 is a, where a≥150 mm.

[0317] a can be any point value among 150mm, 180mm, 200mm, 240mm, 260mm, 280mm, 300mm, 350mm, 400mm, 450mm, 500mm, etc., or a range value between any two of them.

[0318] In this embodiment, the length of the housing 11 is longer when a≥150 mm, which is beneficial to improving the energy density of the battery cell 10 .

[0319] In some embodiments, a ≥ 300 mm.

[0320] a can be any point value among 300mm, 350mm, 400mm, 450mm, 500mm, 550mm, 600mm, 650mm, 700mm, 750mm, 800mm, 850mm, 900mm, 950mm, 1000mm, etc., or a range value between any two of them.

[0321] In this embodiment, a≥300 mm, which further improves the energy density of the battery cell 10 .

[0322] In some embodiments, the housing 11 is made of aluminum alloy. The aluminum alloy housing 11 is lightweight, has good ductility, and is easy to form.

[0323] Please refer to Figures 31 and 32. Figure 31 is a front view of a battery cell 10 provided in some embodiments of the present application; Figure 32 is a PP cross-sectional view of the battery cell 10 shown in Figure 31. Embodiments of the present application provide a battery cell 10 comprising an electrode assembly 2, an end cap 12, and a housing 11 provided in any of the aforementioned embodiments. The electrode assembly 2 is accommodated within the accommodation space 111. The end cap 12 corresponds to the opening one-to-one and seals the opening.

[0324] In some embodiments, please refer to FIG. 33 , which is a partial enlarged view of the battery cell 10 shown in FIG. 32 at position Q. The housing 11 includes a first wall 1131 , which is provided with a pressure relief mechanism 13 . The battery cell 10 also includes a support member 6 , which is disposed between the first wall 1131 and the electrode assembly 2 and is configured to support the electrode assembly 2 .

[0325] The first wall portion 1131 can be one of the multiple walls 113 in the housing 11, located at the bottom. The pressure relief mechanism 13 is located in the first wall portion 1131. The thickness direction of the first wall portion 1131 is the direction of gravity of the housing 11, and the thickness direction of the first wall portion 1131 is the second direction Y. In the battery cell 10, when the battery cell 10 is placed on other components (e.g., the casing 20 of the battery 100), the other components are located at the bottom of the battery cell 10, and the first wall portion 1131 in the housing 11 contacts the other components.

[0326] The pressure relief mechanism 13 and the first wall portion 1131 can be provided separately or integrally. As an example, in the embodiment shown in FIG33 , the pressure relief mechanism 13 and the first wall portion 1131 are integrally formed.

[0327] The support member 6 is a component disposed between the electrode assembly 2 and the first wall portion 1131 and supports the electrode assembly 2. The support member 6 is used to bear the weight of the electrode assembly 2. The support member 6 can be a plate-shaped structure disposed between the electrode assembly 2 and the first wall portion 1131. The support member 6 is located on the side of the first wall portion 1131 facing the electrode assembly 2. The weight of the electrode assembly 2 can be transmitted to the first wall portion 1131 through the support member 6.

[0328] The support member 6 can directly support the electrode assembly 2, that is, the support member 6 is located at the bottom of the electrode assembly 2 and is in direct contact with the electrode assembly 2; the support member 6 can also indirectly support the electrode assembly 2, that is, the support member 6 is located at the bottom of the electrode assembly 2, and other components are arranged between the support member 6 and the electrode assembly 2.

[0329] As an example, the battery cell 10 further includes a first insulating member 4, which is wrapped around the electrode assembly 2 and is used to insulate and isolate the electrode assembly 2 from the housing 11. The first insulating member 4 is partially located between the electrode assembly 2 and the support member 6, and the support member 6 indirectly supports the electrode assembly 2 through the first insulating member 4.

[0330] In this embodiment, the support member 6 can bear the gravity of the electrode assembly 2 and can separate the first wall portion 1131 and the electrode assembly 2, thereby reducing the impact of the electrode assembly 2 on the pressure relief mechanism 13 and increasing the life of the pressure relief mechanism 13.

[0331] In some embodiments, please refer to FIG34 , which is a partial enlarged view of the battery cell 10 shown in FIG33 at position S. A relief groove 61 is provided on the side of the support member 6 facing the first wall portion 1131 . The projection of the pressure relief mechanism 13 is located within the relief groove 61 along the thickness direction of the first wall portion 1131 .

[0332] Along the thickness direction of the first wall portion 1131, the avoidance groove 61 is provided on the surface of the support member 6 facing the first wall portion 1131. The avoidance groove 61 can be a circular groove, an elliptical groove, a rectangular groove, etc. A circular groove refers to a groove with a circular cross-section, an elliptical groove refers to a groove with an elliptical cross-section, and a rectangular groove refers to a groove with a rectangular cross-section perpendicular to the thickness direction of the first wall portion 1131.

[0333] In this embodiment, the provision of the avoidance groove 61 of the support member 6 reduces the risk of the support member 6 directly acting on the pressure relief mechanism 13 , thereby increasing the life of the pressure relief mechanism 13 .

[0334] In some embodiments, referring again to FIG. 34 , a relief groove 61 is provided on the side of the support member 6 facing the first wall portion 1131. The first wall portion 1131 has a first inner surface 11312 facing the electrode assembly 2. The first inner surface 11312 is provided with a notched groove 14. A pressure relief mechanism 13 is formed in the area of ​​the first wall portion 1131 corresponding to the notched groove 14. The first wall portion 1131 has a protrusion 15 formed at the edge of the notched groove 14 provided on the first inner surface 11312, protruding from the first inner surface 11312. The relief groove 61 is configured to accommodate at least a portion of the protrusion 15.

[0335] In this embodiment, the integrated pressure relief mechanism 13 is formed by providing a notched groove 14 on the first wall portion 1131. For example, the notched groove 14 can be stamped and formed on the first inner surface 11312. During the stamping process, material accumulates outside the notched groove 14, thereby forming a corresponding protrusion 15 protruding from the first inner surface 11312.

[0336] The protrusion 15 protruding from the first inner surface 11312 may be partially located in the avoidance groove 61 or may be completely located in the avoidance groove 61 .

[0337] In this embodiment, at least a portion of the protrusion 15 is accommodated in the avoidance groove 61 , making the first wall portion 1131 and the support member 6 more compact, freeing up more space for the electrode assembly 2 to improve the energy density of the battery cell 10 .

[0338] In some embodiments, please continue to refer to FIG. 34 , along the thickness direction of the first wall portion 1131 , the height of the protrusion 15 is H2 , the depth of the avoidance groove 61 is H3 , and H2 ≤ H3 .

[0339] H2 can be H3 or H2 < H3. Along the thickness direction of the first wall portion 1131, the protrusion 15 has a second inner surface 151 facing away from the first inner surface 11312. If H2 = H3, the second inner surface 151 is in direct contact with the bottom surface of the avoidance groove 61. If H2 < H3, a gap is provided between the second inner surface 151 and the bottom surface of the avoidance groove 61.

[0340] In this embodiment, H2≤H3, so that the protrusion 15 can be completely accommodated in the avoidance groove 61. On the one hand, the contact area between the support member 6 and the first wall portion 1131 is increased, thereby improving the stability of the support member 6 in the shell 11; on the other hand, the protrusion 15 is hardly affected by the force of the support member 6, thereby reducing the risk of the support member 6 applying a force to the protrusion 15 and reducing the life of the pressure relief mechanism 13.

[0341] In some embodiments, please continue to refer to FIG. 35 , which is a partial enlarged view of a battery cell 10 provided in other embodiments of the present application. The first wall portion 1131 further includes a first outer surface 11313 facing away from the electrode assembly 2. Along the thickness direction of the first wall portion 1131 , a first inner surface 11312 is disposed opposite the first outer surface 11313. The first outer surface 11313 is provided with a notched groove 14. The notched groove 14 disposed on the first outer surface 11313 is disposed opposite the notched groove 14 disposed on the first inner surface 11312. The first wall portion 1131 includes a protrusion 15 formed at the edge of the notched groove 14 disposed on the first outer surface 11313, protruding from the first outer surface 11313.

[0342] An embodiment of the present application provides a battery 100 , comprising the battery cell 10 provided in any one of the above embodiments.

[0343] An embodiment of the present application provides an electrical device, comprising a battery cell 10 provided by any one of the above embodiments, wherein the battery cell 10 is used to provide electrical energy.

[0344] An embodiment of the present application provides a shell 11, which is formed by bending a plate. The end faces of the plate are welded together to enclose a receiving space 111 with openings at opposite ends. The receiving space 111 is used to accommodate the electrode assembly 2 of the battery cell 10.

[0345] The housing 11 is a rectangular parallelepiped housing and includes a first wall 1131, a second wall 1132, a third wall 1133, and a fourth wall 1134. The first wall 1131 is disposed opposite the second wall 1132, and the third wall 1133 is disposed opposite the fourth wall 1134. The housing 11 is provided with a pressure relief mechanism 13, which is integrally formed with the first wall 1131. The first wall 1131 is provided with a notched groove 14, with the pressure relief mechanism 13 formed in the area corresponding to the notched groove 14. The first wall 1131 has a first inner surface 11312 facing the interior of the housing 11. A protrusion 15 is formed on the edge of the notched groove 14, projecting from the first inner surface 11312. Along the thickness direction of the first wall portion 1131, the thickness of the first wall portion 1131 is D. The residual thickness of the area of ​​the first wall portion 1131 where the notch groove 14 is provided is H1, where H1 / D ≤ 0.7, H1 ≥ 0.05 mm, and D ≤ 0.6 mm. The connection points 114 of the end surfaces of the plate are located on the second wall portion 1132. The maximum distance between the third wall portion 1133 and the fourth wall portion 1134 is A, and the minimum distance between the first wall portion 1131 and the second wall portion 1132 is B, where A < B. The openings at both ends of the shell 11 are arranged opposite each other along the length of the shell 11. The length of the shell 11 is a, the width of the shell 11 is b, and the height of the shell 11 is c, where b < c ≤ a / 1.5, and a ≥ 150 mm.

[0346] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0347] The above embodiments are intended only to illustrate the technical solutions of this application and are not intended to limit this application. Those skilled in the art will appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application are intended to be within the scope of protection of this application.

Claims

1. A shell for a battery cell, the shell is formed by bending a plate, the first and second ends of the plate are connected to each other to enclose a receiving space with openings at opposite ends, the receiving space is used to receive the electrode assembly of the battery cell.

2. The housing according to claim 1, wherein: The housing includes a plurality of wall portions, and the plurality of wall portions enclose the accommodation space; The shell is provided with a pressure relief mechanism, and the connection positions of the two end portions and the pressure relief mechanism are located at two different wall portions.

3. The housing according to claim 2, wherein: The plurality of wall portions include a first wall portion and a second wall portion that are oppositely disposed, the pressure relief mechanism is located on the first wall portion, and the connection position is located on the second wall portion.

4. The housing according to claim 3, wherein: The second wall portion includes a first connecting wall and a second connecting wall which are arranged opposite to the first wall portion, and the first connecting wall and the second connecting wall respectively form the two end portions.

5. The housing according to claim 4, wherein: The first connecting wall has a first end surface, and the second connecting wall has a second end surface. The first end surface and the second end surface are end surfaces at both ends of the plate, respectively, and the first end surface is connected to the second end surface.

6. The housing according to claim 4, wherein: Along the thickness direction of the first wall portion, the first connecting wall and the second connecting wall are at least partially stacked and connected to each other.

7. The housing according to any one of claims 4 to 6, wherein: The housing further includes a third wall portion and a fourth wall portion which are arranged opposite to each other. The third wall portion connects the first wall portion and the first connecting wall, and the fourth wall portion connects the first wall portion and the second connecting wall.

8. The housing according to claim 7, wherein: The maximum distance between the third wall portion and the fourth wall portion is A, and the minimum distance between the first wall portion and the second wall portion is B, and A<B.

9. The housing according to any one of claims 2 to 8, wherein: The plurality of wall portions include a first wall portion, the pressure relief mechanism is provided separately from the shell, and the pressure relief mechanism is installed on the first wall portion.

10. The housing according to any one of claims 2 to 8, wherein: The plurality of wall portions include a first wall portion, and the pressure relief mechanism is integrally formed with the first wall portion.

11. The housing according to claim 10, wherein: The first wall portion is provided with a notch groove, and the pressure relief mechanism is formed corresponding to the area of ​​the first wall portion where the notch groove is provided.

12. The housing according to claim 11, wherein: The first wall portion has a first inner surface facing the interior of the housing, and the notch groove is disposed on the first inner surface.

13. The housing according to claim 11, wherein: The first wall portion has a first outer surface facing away from the interior of the housing, and the notch groove is disposed on the first outer surface.

14. The housing according to claim 11, wherein: The first wall portion has a first inner surface facing the interior of the housing and a first outer surface facing away from the interior of the housing, and the first inner surface and the first outer surface are both provided with the notch groove.

15. The housing according to claim 14, wherein: The notched groove disposed on the first outer surface is disposed opposite to the notched groove disposed on the first inner surface.

16. A housing as claimed in claim 12, 14 or 15, wherein: The first wall portion has a protrusion formed at an edge of the notched groove and protrudes from the first inner surface.

17. The housing according to any one of claims 13 to 15, wherein: The first wall portion has a protrusion formed at an edge of the notched groove and protruding from the first outer surface.

18. The housing according to any one of claims 11 to 17, wherein: Along the thickness direction of the first wall portion, the thickness of the first wall portion is D, and the residual thickness of the first wall portion in a region where the notch groove is provided is H1, and H1 / D≤0.

7.

19. The housing of claim 18, wherein: H1≥0.05mm.

20. The housing according to claim 18 or 19, wherein: D≤0.6mm.

21. The housing according to any one of claims 11 to 20, wherein: The score groove includes a first groove segment and a second groove segment, and the first groove segment intersects with the second groove segment.

22. The housing of claim 21, wherein: The notched groove further includes a third groove segment, the first groove segment and the third groove segment are arranged opposite to each other, and the third groove segment intersects with the second groove segment.

23. The housing of claim 22, wherein: The first slot section, the second slot section and the third slot section are connected in sequence.

24. The housing of claim 22, wherein: The first slot segment intersects with the second slot segment at a first position, and the first position deviates from the two ends of the first slot segment in the extension direction; the third slot segment intersects with the second slot segment at a second position, and the second position deviates from the two ends of the third slot segment in the extension direction.

25. The housing of claim 24, wherein: The first position is located at the midpoint of the first slot segment in the extension direction, and the second position is located at the midpoint of the third slot segment in the extension direction.

26. The housing according to any one of claims 11 to 20, wherein: The notched groove is a groove extending along a non-closed track.

27. The housing of claim 26, wherein: The notched groove is an arc-shaped groove.

28. The housing according to any one of claims 11 to 20, wherein: The notched groove is a groove extending along a closed track.

29. The housing of claim 28, wherein: The notched groove is an annular groove.

30. The housing according to any one of claims 2 to 29, wherein: The openings at both ends of the shell are arranged opposite to each other along a first direction, the multiple wall portions include a first wall portion, the first wall portion is provided with a plurality of the pressure relief mechanisms, and the plurality of the pressure relief mechanisms are arranged along the first direction.

31. The housing of claim 30, wherein: The first wall portion is provided with two pressure relief mechanisms.

32. The housing of claim 31, wherein: The two pressure relief mechanisms are respectively a first pressure relief mechanism and a second pressure relief mechanism; Along the first direction, the shell has a first opening end and a second opening end opposite to each other. The first pressure relief mechanism is closer to the first opening end than the second pressure relief mechanism. The distance between the first pressure relief mechanism and the second pressure relief mechanism is K1, the distance between the first pressure relief mechanism and the first opening end is K2, and the distance between the second pressure relief mechanism and the second opening end is K3, K2<K1, K3<K1.

33. The housing according to any one of claims 1-5 and 7-32, wherein: The end surfaces at both ends of the plate are connected to each other.

34. A housing as claimed in any one of claims 1 to 33, wherein: The two ends are connected by welding.

35. The housing of any one of claims 1 to 34, wherein: The housing includes a plurality of wall portions, and the plurality of wall portions enclose the accommodation space; The connection position of the two end portions is located at one of the wall portions.

36. The housing of any one of claims 1 to 35, wherein: The wall thickness of the shell is L, L≤0.6mm.

37. A housing as claimed in any one of claims 1 to 36, wherein: The shell is a rectangular parallelepiped shell.

38. The housing of claim 37, wherein: The openings at both ends of the shell are arranged opposite to each other along the length direction of the shell, the length of the shell is a, the width of the shell is b, the height of the shell is c, and b≤c≤a / 1.

5.

39. The housing of any one of claims 1 to 38, wherein: The openings at both ends of the shell are arranged opposite to each other along the length direction of the shell, and the length of the shell is a, where a≥150 mm.

40. The housing of claim 39, wherein: a≥300mm.

41. A housing as claimed in any one of claims 1 to 40, wherein: The material of the shell includes aluminum alloy.

42. A battery cell, comprising: A housing as claimed in any one of claims 1 to 41; An electrode assembly is accommodated in the accommodation space; The end covers correspond to the openings one by one, and the end covers close the openings.

43. The battery cell according to claim 42, wherein: The housing comprises a first wall portion, wherein the first wall portion is provided with a pressure relief mechanism; The battery cell further includes a support member disposed between the first wall portion and the electrode assembly, the support member being configured to support the electrode assembly.

44. The battery cell according to claim 43, wherein: A relief groove is provided on one side of the support member facing the first wall portion, and a projection of the pressure relief mechanism is located in the relief groove along the thickness direction of the first wall portion.

45. The battery cell according to claim 43 or 44, wherein: A side of the support member facing the first wall portion is provided with an avoidance groove; The first wall portion has a first inner surface facing the electrode assembly, the first inner surface is provided with a notch groove, the first wall portion forms the pressure relief mechanism corresponding to the area where the notch groove is provided, and the first wall portion forms a protrusion protruding from the first inner surface at the edge of the notch groove; Wherein, the avoidance groove is configured to accommodate at least a portion of the protrusion.

46. ​​The battery cell according to claim 45, wherein: Along the thickness direction of the first wall portion, the height of the protrusion is H2, the depth of the avoidance groove is H3, and H2≤H3.

47. A battery comprising the battery cell according to any one of claims 42 to 46.

48. An electrical device comprising the battery cell according to any one of claims 42 to 46, wherein the battery cell is used to provide electrical energy.

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