Battery cell, battery device, and electric device

Abstract

The application relates to a battery monomer, a battery device and a power utilization device, comprising a shell, the shell comprising a first wall and a second wall, the first wall comprising a wall body and a pressure relief part, the wall body and the pressure relief part being integrally formed, the minimum thickness h1 of the wall body is greater than the maximum thickness h2 of the pressure relief part along the thickness direction of the wall body, and the Vickers hardness of the first wall is less than or equal to the Vickers hardness of the second wall. The application can reduce the failure probability of the pressure relief part on the basis of guaranteeing the structural strength of the shell, and improve the reliability of the battery monomer.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, battery device, and power supply device. Background Technology

[0002] With the gradual popularization of new energy technologies, power battery technology has continued to develop. Power batteries are favored by the new energy industry due to their superior characteristics such as large energy storage capacity, stable power supply capacity, and long service life. Among them, the battery casing, as an important component of the power battery, requires lightweight design while ensuring structural strength.

[0003] The battery consists of a casing and a pressure relief section. A groove is machined into a specific area of ​​the pressure relief section, creating a weak point in the entire structure. When the internal pressure of the battery reaches or exceeds the pressure that the grooved area can withstand, the material at the groove will first fracture and propagate under pressure, thus opening the pressure relief section. However, this type of battery cannot reduce the failure probability of the pressure relief section while ensuring the structural strength of the casing. Utility Model Content

[0004] In view of the above problems, this application provides a battery cell, a battery device, and an electrical device that can reduce the failure probability of the pressure relief part and improve the reliability of the battery cell while ensuring the structural strength of the casing.

[0005] In a first aspect, this application provides a battery cell, including a housing, the housing comprising: a first wall, the first wall comprising a wall body and a pressure relief portion, the wall body and the pressure relief portion being integrally formed, the tensile strength e of the first wall satisfying the condition: 240MPa≤e≤1000MPa; a second wall, the second wall being welded to the first wall, the tensile strength f of the second wall satisfying the condition: 240MPa≤e≤1000MPa; along the thickness direction of the wall body, the minimum thickness h1 of the wall body is greater than the maximum thickness h2 of the pressure relief portion, and the Vickers hardness of the first wall is less than the Vickers hardness of the second wall.

[0006] In the technical solution of this application embodiment, by integrally molding the pressure relief part and the wall body, the welding process between the pressure relief part and the wall body is reduced, the production process is simplified, the pre-welding preparation work and post-welding inspection work are reduced, and the production efficiency is improved. It also reduces performance inconsistencies caused by differences in welding processes, ensuring the quality of the battery cells. Furthermore, it helps reduce problems caused by welding processes, such as welding defects, thereby reducing the failure probability of the pressure relief part and improving the reliability of the battery cells. By setting the minimum thickness of the wall body to be greater than the maximum thickness of the pressure relief part, since the thickness of the pressure relief part is relatively small, when the internal pressure of the battery reaches a certain value, the pressure relief part will preferentially open to release pressure, improving the controllability and accuracy of the pressure relief process and reducing the risk of battery rupture due to excessive pressure. Moreover, since the thickness of the wall body is relatively large, it can provide stable support for the entire battery structure during normal battery operation and pressure relief, reducing structural deformation or damage caused by pressure fluctuations and improving the reliability of the battery cells. By setting the Vickers hardness of the first wall to be less than that of the second wall, while maintaining the strength of the shell structure, it helps to further reduce the stamping difficulty of the pressure relief part and improve the stamping effect of the pressure relief part. By setting the tensile strength of both the first and second walls within the range of 240MPa to 1000MPa, this application increases the tensile strength of the casing. The higher tensile strength of the casing, compared to aluminum-cased explosion-proof valves in related technologies, helps to accommodate the high expansion forces of high-energy-density battery cells, thereby withstanding the internal expansion forces generated by the high-energy-density battery cells during charging and discharging. This reduces the risk of casing deformation or cracking, and battery cell leakage, improving the reliability of individual battery cells. Simultaneously, the high tensile strength also makes the molding of the explosion-proof valve more challenging.

[0007] In some embodiments, the minimum thickness h1 of the wall body and the maximum thickness h2 of the pressure relief part satisfy the condition: 0.08h1≤h2≤0.3h1.

[0008] By setting the maximum thickness h2 of the pressure relief section to be ≥0.08h1, the risk of processing difficulties or accidental breakage caused by the pressure relief section being too thin is reduced; by setting the maximum thickness h2 of the pressure relief section to be ≤0.3h1, it is helpful to ensure that the pressure relief section is thin enough to break first and open the pressure relief, while the wall body maintains structural support.

[0009] In some embodiments, the minimum thickness h1 of the wall body satisfies the condition: 0.6mm ≤ h1 ≤ 1mm.

[0010] By setting the minimum thickness h1 of the wall body between 0.6 mm and 1 mm, on the one hand, it helps ensure that the wall body has sufficient mechanical strength, reducing the risk of plastic deformation or cracking of the battery cells during normal use, providing a stable support foundation for the pressure relief section, and reducing the risk of pressure relief section failure due to an excessively thin wall body. On the other hand, it helps control the weight of the casing and reduces the excessive increase in the weight of the battery cells.

[0011] In some embodiments, the maximum thickness h2 of the pressure relief section satisfies the condition: 0.04mm ≤ h2 ≤ 0.3mm.

[0012] By setting the maximum thickness h2 of the pressure relief section between 0.04mm and 0.3mm, on the one hand, it helps to ensure that the pressure relief section is thin enough to rupture first when the internal pressure of the battery reaches the safety threshold, reducing the problem of failure in other areas of the casing first; on the other hand, it helps to reduce the risk of excessive opening pressure caused by excessively thick pressure relief section, and improve the reliability of battery cells.

[0013] In some embodiments, the housing includes a body and an end cap, the end cap being connected to the body, the end cap serving as the first wall, and the body serving as the second wall;

[0014] The minimum thickness h1 of the wall body is greater than or equal to the maximum wall thickness h3 of the second wall.

[0015] By setting the minimum thickness h1 of the main wall to be greater than or equal to the maximum wall thickness h3 of the second wall, the main wall can withstand higher mechanical loads, improving the reliability of the battery cell. The second wall can be appropriately thinned, which helps to reduce the overall weight of the casing while still maintaining the necessary support function.

[0016] In some embodiments, the maximum wall thickness h3 of the second wall satisfies the condition: 0.1mm≤h3≤0.4mm.

[0017] By setting the maximum wall thickness h3 of the second wall between 0.1 mm and 0.4 mm, on the one hand, it helps to ensure that the second wall has sufficient mechanical support to prevent deformation during battery assembly or transportation; on the other hand, it can effectively control the weight of the casing.

[0018] In some embodiments, the Vickers hardness of the first wall is a, and the Vickers hardness of the second wall is b, wherein a and b satisfy the condition: a≤b.

[0019] By setting the Vickers hardness of the first wall to be less than or equal to that of the second wall, the lower hardness of the first wall makes it easier to stamp the pressure relief section and ensures that the pressure relief section can break preferentially, providing moderate plastic deformation capacity and absorbing impact energy; the higher hardness of the second wall helps to maintain the overall rigidity of the shell and resist external mechanical impact.

[0020] In some embodiments, the Vickers hardness α of the first wall satisfies the condition: 100MPa≤a≤250MPa.

[0021] By setting the Vickers hardness α of the first wall between 100 MPa and 250 MPa, on the one hand, it helps to ensure the basic structural strength of the first wall and maintain the morphological stability of the pressure relief section; on the other hand, it helps to maintain sufficient plasticity to ensure controllable fracture in the event of thermal runaway.

[0022] In some embodiments, the Vickers hardness b of the second wall satisfies the condition: 100MPa≤b≤380MPa.

[0023] Setting the Vickers hardness b of the second wall between 100MPa and 380MPa helps ensure basic resistance to deformation while withstanding higher mechanical impacts, thus improving the reliability of the battery cell.

[0024] In some embodiments, the yield strength of the first wall is c, and the yield strength of the second wall is d, wherein c and d satisfy the condition: c ≤ d.

[0025] By setting a lower yield strength c for the first wall, the first wall preferentially undergoes plastic deformation to absorb impact energy; by setting a higher yield strength d for the second wall, it helps to maintain rigid support.

[0026] In some embodiments, the yield strength c of the first wall satisfies the condition: 140MPa≤c≤500MPa.

[0027] Setting the yield strength c of the first wall between 140 MPa and 500 MPa helps ensure the structural integrity of the shell and allows it to withstand higher mechanical impacts.

[0028] In some embodiments, the yield strength d of the second wall satisfies the condition: 140MPa≤d≤1000MPa.

[0029] By setting the yield strength d of the second wall between 140MPa and 1000MPa, on the one hand, the structural strength of the second wall is effectively ensured, thereby providing effective support for the first wall; on the other hand, the strength of the second wall is kept within a suitable range, reducing the problem that the shell is too rigid due to excessive strength, and the first wall cannot deform and absorb energy well.

[0030] In some embodiments, the tensile strength e of the first wall satisfies the condition: 240MPa≤e≤600MPa.

[0031] By setting the tensile strength e of the first wall between 240MPa and 600MPa, it has high tensile strength and fracture toughness, which can effectively reduce the risk of the pressure relief part breaking under impact load and ensure that the pressure relief process is stable and controllable.

[0032] In some embodiments, the tensile strength f of the second wall satisfies the condition: 240MPa≤f≤1000MPa.

[0033] By setting the tensile strength f of the second wall between 240MPa and 1000MPa, the fatigue resistance is high, and it can withstand pressure cycles without fatigue fracture, thus improving the reliability of the battery cell.

[0034] In some embodiments, the material of the second wall includes a titanium alloy, and the material of the first wall includes a titanium alloy; the Ti content in the first wall is greater than or equal to the Ti content in the second wall.

[0035] By setting a higher Ti content in the first wall, the material is closer to the properties of pure titanium, with better plasticity and toughness, but lower strength, making the first wall more prone to plastic deformation under impact load. By setting a lower Ti content in the second wall, the yield strength and rigidity of the second wall can be significantly improved, enabling it to maintain its structural support capacity during impact.

[0036] In some embodiments, the Ti content in the second wall is 80%-99.6%.

[0037] By setting the Ti content in the second wall to between 80% and 99.6%, on the one hand, the risk of the second wall easily breaking under impact load is reduced; on the other hand, it helps to reduce the problem that the second wall cannot provide effective support for the first wall when its strength is too low.

[0038] In some embodiments, the Ti content in the first wall is 90%-99.6%.

[0039] By setting the Ti content in the first wall to 90%-99.6%, it exhibits better plasticity and toughness but lower strength, making the first wall more prone to plastic deformation under impact loads.

[0040] In some embodiments, the pressure relief portion is a groove formed by stamping the wall body.

[0041] By setting the pressure relief part as a groove formed by stamping the wall body, the groove and the wall body are integrally formed without welding or assembly interfaces, reducing the risk of pressure relief failure caused by leakage at the connection point and improving the overall sealing performance of the shell.

[0042] In some embodiments, the extension direction of the pressure relief portion forms an angle with the wall body; or the extension direction of the pressure relief portion is parallel to the wall body.

[0043] By setting the extension direction of the pressure relief section to form an angle with the wall body, the reaction force generated when the high-pressure gas is ejected can guide the airflow to deflect in a specific direction, reducing the direct impact of the pressure relief airflow on the internal structure of the battery or adjacent battery cells, and lowering the risk of thermal runaway. By setting the extension direction of the pressure relief section to be parallel to the wall body, the stress within the wall body is evenly distributed along the extension direction, reducing unexpected cracking caused by localized stress concentration.

[0044] In some embodiments, the minimum distance h4 between the surface of the pressure relief portion near the second wall and the surface of the wall body near the second wall is greater than 0; and / or

[0045] The minimum distance h5 between the surface of the pressure relief section facing away from the second wall and the surface of the wall body facing away from the second wall is greater than 0.

[0046] By setting the distance between the pressure relief section and both the inner and outer sides to be greater than 0, it is ensured that the pressure relief section does not completely penetrate the wall body, which can prevent the pressure relief section from cracking or leaking prematurely due to excessive thinning under normal operating conditions, thereby improving the reliability of the battery cell.

[0047] In some embodiments, the pressure relief section includes at least one bend.

[0048] By incorporating a pressure relief section including at least one bend, this section is more prone to plastic deformation or cracking under the same pressure, gradually releasing internal pressure and reducing the risk of shell bursting due to instantaneous high pressure.

[0049] In some embodiments, the pressure relief section includes at least two connecting plates connected in sequence and arranged at an included angle, with two adjacent connecting plates forming a bending section.

[0050] By setting the pressure relief section to include at least two connecting plates that are connected sequentially and arranged at an angle, the trigger pressure can be reduced compared to a straight pressure relief section, ensuring pressure relief at a lower pressure.

[0051] In some embodiments, the groove shape along the thickness direction perpendicular to the first wall includes any one of racetrack shape, circular shape, or multi-branched cross shape.

[0052] By setting grooves of various shapes, the pressure relief function can be precisely controlled according to the battery shape, application scenario and safety requirements, maximizing the adaptation of process costs while ensuring reliability.

[0053] In some embodiments, the housing includes electrode terminals disposed on a third wall opposite to the first wall.

[0054] By placing the electrode terminals on the third wall opposite to the first wall, the first wall and the electrode terminals are located on opposite sides of the housing. This helps prevent the high-temperature jet from directly impacting the electrode terminals during pressure relief, reducing the risk of short circuits and improving the reliability of the battery cells.

[0055] In some embodiments, the housing comprises a titanium shell or a steel shell.

[0056] By using titanium or steel shells, the shell strength is high, and it has the advantages of high-energy chemical system and lightweight high strength. There is a tendency to use shells with thinner walls and higher strength, which helps to adapt to the high expansion force of high energy density cells and improve the reliability of battery cells. At the same time, the molding of explosion-proof valves is more difficult when using titanium or steel shells.

[0057] In some embodiments, the first wall is a structural member made of TA1 or TA2.

[0058] The first wall, made of the aforementioned material, has a low yield strength and excellent plasticity, making it easy to form a thin-walled explosion-proof valve structure through stamping, thereby ensuring accurate opening and pressure relief under a predetermined pressure.

[0059] In some embodiments, the second wall is a structural component made of any one of TA1, TA4G, or TC4.

[0060] The second wall, made of the aforementioned materials, possesses excellent strength and corrosion resistance, enabling it to withstand the internal expansion forces generated during the charging and discharging of high-energy-density cells, thus reducing the risk of casing deformation or breakage.

[0061] In some embodiments, the battery cell is a prismatic battery.

[0062] Secondly, this application provides a method for preparing a battery cell, comprising:

[0063] A housing is provided, the housing including a connected first wall and a second wall;

[0064] The first wall includes a wall body and a pressure relief part integrally formed with the wall body; along the thickness direction of the wall body, the minimum thickness h1 of the wall body is controlled to be greater than the maximum thickness h2 of the pressure relief part, and the Vickers hardness of the first wall is controlled to be less than the Vickers hardness of the second wall.

[0065] By using the above method to prepare battery cells, the stamping difficulty of the pressure relief section is reduced and the stamping effect of the pressure relief section is improved while maintaining the structural strength of the casing. At the same time, when the internal pressure of the battery reaches a certain value, the pressure relief section will open first to relieve pressure, which improves the controllability and accuracy of the pressure relief process and reduces the risk of battery rupture due to excessive pressure.

[0066] In some embodiments, prior to the step of providing the first wall, the preparation method further includes:

[0067] A groove is formed by stamping on the wall body, and the groove is the pressure relief part.

[0068] By using the above method to prepare the pressure relief section, the groove and the wall body are integrated into one structure, without weak links such as welding and bonding, which simplifies the production process, reduces the preparation work before welding and the inspection work after welding, and improves production efficiency; at the same time, it also reduces the performance inconsistency caused by differences in welding process, and ensures the quality of battery cells.

[0069] In some embodiments, the step of stamping the groove on the wall body specifically includes:

[0070] An initial groove is formed by stamping on the wall body;

[0071] The initial groove is thinned to form a grooved groove.

[0072] By using a staged stamping process of initial groove and thinning, the scoring groove can be prepared, which can improve the reliability of the process and the product, while helping to reduce mold wear and production costs, and reduce the risk of mold wear or material cracking caused by one-time stamping.

[0073] In some embodiments, the step of thinning the initial groove to form a scoring groove specifically includes:

[0074] The maximum thickness h2 of the pressure relief section at the location of the groove is controlled to meet the condition: 0.04mm≤h2≤0.3mm.

[0075] If h2 ≤ 0.04 mm, the excessive thickness may cause accidental pressure release under normal conditions; if h2 ≥ 0.3 mm, the excessive thickness of the pressure relief section may prevent timely activation under abnormal high pressure. Therefore, by controlling the maximum thickness h2 of the pressure relief section at the groove location to meet the condition: 0.04 mm ≤ h2 ≤ 0.3 mm, the trigger pressure can be controlled within a safe range, improving the reliability of the battery cell.

[0076] In some embodiments, it also includes;

[0077] The minimum thickness h1 of the wall body is controlled to meet the condition: 0.6mm≤h1≤1mm.

[0078] By controlling the minimum thickness h1 of the wall body to be between 0.6 mm and 1 mm, on the one hand, it helps to ensure that the wall body has sufficient mechanical strength, reducing the risk of plastic deformation or cracking of the battery cells during normal use, providing a stable support foundation for the pressure relief section, and reducing the risk of pressure relief section failure due to an excessively thin wall body. On the other hand, it helps to control the weight of the casing and reduce the excessive increase in the weight of the battery cells.

[0079] Thirdly, this application provides a battery device that includes the battery cell described in the above embodiments.

[0080] When the battery device provided in this application embodiment is used, the integral molding of the pressure relief part and the wall body helps to reduce the welding process between the pressure relief part and the wall body, simplifying the production process, reducing pre-welding preparation work and post-welding inspection work, and improving production efficiency. It also reduces performance inconsistencies caused by differences in welding processes, ensuring the quality of the battery cells. Furthermore, it helps to reduce problems caused by welding processes, such as welding defects, thereby reducing the failure probability of the pressure relief part and improving the reliability of the battery cells. By setting the minimum thickness of the wall body to be greater than the maximum thickness of the pressure relief part, the pressure relief part will preferentially open to release pressure when the internal pressure of the battery reaches a certain value, improving the controllability and accuracy of the pressure relief process and reducing the risk of battery rupture due to excessive pressure. Moreover, because the wall body is relatively thicker, it can provide stable support for the entire battery structure during normal battery operation and pressure relief, reducing structural deformation or damage caused by pressure fluctuations and improving the reliability of the battery cells. By setting the Vickers hardness of the first wall to be less than that of the second wall, the stamping difficulty of the pressure relief part is further reduced while maintaining the strength of the shell structure, improving the stamping effect of the pressure relief part. By setting the tensile strength of both the first and second walls within the range of 240MPa to 1000MPa, this application increases the tensile strength of the casing. The higher tensile strength of the casing, compared to the aluminum-cased explosion-proof valves in related technologies, helps to adapt to the high expansion force of high-energy-density cells, thereby withstanding the internal expansion force generated by high-energy-density cells during charging and discharging, reducing the risk of casing deformation or cracking, and improving the reliability of battery cells. At the same time, with high tensile strength, the molding of the explosion-proof valve is more difficult.

[0081] Fourthly, this application provides an electrical device, including the battery device in the above embodiments, wherein the battery device is used to provide electrical energy.

[0082] When the electrical device provided in this application embodiment is in use, the battery device composed of the battery cells provided in this application embodiment provides electrical energy to the electrical device. Since the pressure relief section and the wall body are integrally formed, it helps to reduce the welding process between the pressure relief section and the wall body, simplifying the production process, reducing pre-welding preparation work and post-welding inspection work, and improving production efficiency; it also reduces performance inconsistencies caused by differences in welding processes, ensuring the quality of the battery cells; in addition, it helps to reduce problems caused by welding processes, such as welding defects, thereby reducing the failure probability of the pressure relief section and improving the reliability of the battery cells. By setting the minimum thickness of the wall body to be greater than the maximum thickness of the pressure relief section, since the thickness of the pressure relief section is relatively small, when the internal pressure of the battery reaches a certain value, the pressure relief section will preferentially open to relieve pressure, improving the controllability and accuracy of the pressure relief process and reducing the risk of battery rupture due to excessive pressure; and since the thickness of the wall body is relatively large, it can provide stable support for the entire battery structure during normal battery operation and pressure relief, reducing structural deformation or damage caused by pressure fluctuations and improving the reliability of the battery cells. By setting the Vickers hardness of the first wall to be lower than that of the second wall, the stamping difficulty of the pressure relief section is further reduced and the stamping effect of the pressure relief section is improved while maintaining the structural strength of the casing. By setting the tensile strength of both the first and second walls within the range of 240MPa to 1000MPa, this application increases the tensile strength of the casing. The higher tensile strength of the casing, compared with the aluminum-cased explosion-proof valves in related technologies, helps to adapt to the high expansion force of high-energy-density cells, thereby withstanding the internal expansion force generated by high-energy-density cells during charging and discharging, reducing the risk of casing deformation or cracking, and improving the reliability of the battery cells. At the same time, with high tensile strength, the molding difficulty of the explosion-proof valve is higher.

[0083] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0084] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0085] Figure 1 The electrical device provided in some embodiments of this application is a structural schematic diagram of a vehicle.

[0086] Figure 2This is an exploded structural diagram of a battery device provided in some embodiments of this application.

[0087] Figure 3 Axial view of a battery cell provided for some embodiments of this application.

[0088] Figure 4 Axial view of a battery cell provided for other embodiments of this application.

[0089] Figure 5 A front view of a battery cell provided for some embodiments of this application.

[0090] Figure 6 Axial view of the first wall of the housing provided for some embodiments of this application.

[0091] Figure 7 A top view of the first wall of the housing provided for some embodiments of this application.

[0092] Figure 8 The housing provided for some embodiments of this application is in Figure 7 The diagram shows a cross-section at point AA.

[0093] Figure 9 for Figure 8 A magnified schematic diagram of the structure at point A in the middle.

[0094] Figure 10 A top view of the first wall of the housing provided for other embodiments of this application.

[0095] Figure 11 The housing provided for other embodiments of this application is in Figure 10 The diagram shows a cross-section at point BB.

[0096] Figure 12 for Figure 11 A magnified schematic diagram of the structure at point B in the middle.

[0097] Figure 13 An axial view of the first wall of the housing provided for some embodiments of this application.

[0098] The reference numerals in the detailed embodiments are as follows:

[0099] 10000 - Vehicles;

[0100] 1000-battery;

[0101] 1100-cell battery;

[0102] 100 - Shell; 110 - First wall; 111 - Wall body; 112 - Pressure relief part; 1121 - Bending part; 11211 - Connecting plate; 120 - Second wall; 130 - Third wall;

[0103] 200 - Electrode terminal;

[0104] 1200 - Box body; 1210 - Accommodation space; 1220 - First part; 11210 - Second part;

[0105] 2000-Controller;

[0106] 3000-motor. Detailed Implementation

[0107] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0108] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0109] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0110] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0111] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0112] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0113] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0114] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

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

[0116] A typical battery cell includes a casing and a pressure relief section. Scorees are machined into specific areas of the pressure relief section, creating a weak point in the entire structure. When the internal pressure of the battery reaches or exceeds the pressure that the scored area can withstand, the material at the scored area first fractures and expands under pressure, thus opening the pressure relief section. During cyclic charging and discharging, the battery cell assembly undergoes hard expansion, leading to cell leakage. To address this issue, steel-cased battery cells are used. However, for designs requiring lightweight battery cells, the introduction of steel casings results in excessive weight.

[0117] To address the issue of excessive weight in individual battery cells, the applicant's research revealed that to achieve higher energy density and gravimetric energy density, battery cell assemblies utilize high-energy chemical systems and lightweight, high-strength casings, leading to a trend towards thinner-walled, high-strength casings. Therefore, the applicant introduced the development of titanium-cased battery cells, which achieves both high strength and reduced weight. However, the applicant also considered that titanium casings cannot be welded to aluminum or steel explosion-proof valves, necessitating the development of titanium explosion-proof valves. Using welding would increase the probability of failure. Furthermore, the development of titanium-cased battery cells also requires the design of an explosion-proof valve to achieve directional pressure relief within the cell.

[0118] Based on the above considerations, in order to reduce the failure probability of the pressure relief section while ensuring the structural strength of the casing, this application provides a battery cell in which the pressure relief section is integrally formed with the wall body. The minimum thickness of the wall body is greater than the maximum thickness of the pressure relief section. When the internal pressure of the battery reaches a certain value, the pressure relief section will preferentially open to release pressure, improving the controllability and accuracy of the pressure relief process and reducing the risk of battery rupture due to excessive pressure. By setting the Vickers hardness of the first wall to be lower than that of the second wall, the stamping difficulty of the pressure relief section is further reduced while maintaining the structural strength of the casing, thus improving the stamping effect of the pressure relief section.

[0119] The power batteries manufactured using the battery cells disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. Specifically, the electrical devices can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0120] For ease of explanation, the following embodiments will be described using a vehicle as an example of an electrical device according to an embodiment of this application.

[0121] Please see Figure 1 , Figure 1 The diagram shows the structural features of a vehicle provided in some embodiments of this application.

[0122] Vehicle 10000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Vehicle 10000 has a battery internally installed, which can be located at the bottom, front, or rear of the vehicle. The battery can be used to power vehicle 10000; for example, it can serve as the operating power source for vehicle 10000. Vehicle 10000 may also include a controller 2000 and a motor 3000. The controller 2000 is used to control the battery to power the motor 3000, for example, to meet the power needs of vehicle 10000 during starting, navigation, and driving.

[0123] In some embodiments of this application, the battery can not only serve as the operating power source for the vehicle 10000, but also as the driving power source for the vehicle 10000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 10000.

[0124] Please see Figure 2 , Figure 2 Exploded views of batteries provided for some embodiments of this application.

[0125] The battery includes a housing 1200 and battery cells 1100, with the battery cells 1100 housed within the housing 1200. The housing 1200 provides a receiving space 1210 for the battery cells 1100, and the housing 1200 can have various structures. In some embodiments, the housing 1200 may include a first portion 1220 and a second portion 1230, which overlap each other, and together define the receiving space 1210 for accommodating the battery cells 1100. The second part 1230 can be a hollow structure with one end open, and the first part 1220 can be a plate-like structure. The first part 1220 covers the open side of the second part 1230 so that the first part 1220 and the second part 1230 together define the receiving space 1210. Alternatively, the first part 1220 and the second part 1230 can both be hollow structures with one side open, and the open side of the first part 1220 covers the open side of the second part 1230. Of course, the box 1200 formed by the first part 1220 and the second part 1230 can be of various shapes, such as a cylinder, a cuboid, etc.

[0126] In a battery, there can be multiple battery cells 1100, which can be connected in series, parallel, or a combination thereof. A combination thereof means that multiple battery cells 1100 are connected in both series and parallel. Multiple battery cells 1100 can be directly connected in series, parallel, or a combination thereof, and then the entire assembly of the multiple battery cells 1100 is housed within a casing 1200. Alternatively, the battery can be composed of multiple battery cells 1100 first connected in series, parallel, or a combination thereof to form a battery module, and then multiple battery modules are connected in series, parallel, or a combination thereof to form a whole, which is also housed within the casing 1200. The battery may also include other structures; for example, the battery may include a busbar component for electrical connection between the multiple battery cells 1100.

[0127] Each battery cell 1100 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 1100 can be cylindrical, flat, cuboid, or other shapes.

[0128] Please refer to Figure 3 , Figure 3 This is a schematic diagram of the structure of a battery cell provided in some embodiments of this application. A battery cell 1100 refers to the smallest unit that makes up a battery. The battery cell 1100 includes a casing, end caps, cell assemblies, and other functional components.

[0129] An end cap is a component that covers the opening of the battery casing to isolate the internal environment of the battery cell from the external environment. The shape of the end cap can be adapted to the shape of the casing to fit it. Optionally, the end cap can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap is not easily deformed under pressure or impact, allowing the battery cell to have higher structural strength and improved safety performance. Functional components such as electrode terminals 200 can be provided on the end cap. The electrode terminals 200 can be used for electrical connection with the cell assembly to output or input electrical energy to the battery cell. In some embodiments, the end cap can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell reaches a threshold. The end cap can also be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, an insulating structure can also be provided on the inner side of the end cap. The insulating structure can be used to isolate the electrical connection components inside the casing from the end cap to reduce the risk of short circuits. For example, the insulating structure can be made of plastic, rubber, etc.

[0130] The casing is a component used to fit with the end cap to form the internal environment of a battery cell. This internal environment can accommodate the cell assembly, electrolyte, and other components. The casing and end cap can be independent components, with an opening on the casing. The end cap closes the opening to form the internal environment of the battery cell. Alternatively, the end cap and casing can be integrated. Specifically, the end cap and casing can form a common connection surface before other components are inserted into the casing. When the interior of the casing needs to be encapsulated, the end cap closes the casing. The casing can have various shapes and sizes, such as cuboid, cylindrical, or hexagonal prism. Specifically, the shape of the casing can be determined based on the specific shape and size of the cell assembly. The casing can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, or plastic. This application does not impose any special limitations on these materials.

[0131] A battery cell assembly is the component within a single battery cell where electrochemical reactions occur. The casing may contain one or more battery cell assemblies. A battery cell assembly is primarily formed by stacking composite material strips, which are thermally bonded together with a positive electrode, a negative electrode, and a separator between the positive and negative electrodes. The portions of the positive and negative electrodes containing active material constitute the main body of the battery cell assembly, while the portions without active material each constitute a tab. The positive and negative tabs can be located together at one end of the main body or separately at both ends. During the charging and discharging process of the battery device, the positive and negative active materials react with the electrolyte, and the tabs connect to the electrode terminals 200 to form a current loop.

[0132] The following section provides a detailed description of the structure of a single battery cell. Please refer to [link / reference needed]. Figures 3-13 , Figure 3 Axial views of a battery cell provided in some embodiments of this application are shown. Figure 4 Axial views of a battery cell provided in other embodiments of this application are shown. Figure 5 The following is a front view of a battery cell provided in some embodiments of this application. Figure 6 An axial view of the first wall of the housing provided in some embodiments of this application is shown. Figure 7 A top view of the first wall of the housing provided in some embodiments of this application is shown. Figure 8 A cross-sectional view of the first wall of the housing provided in some embodiments of this application is shown. Figure 9 It shows Figure 8 A magnified view of the structure at point A in the middle. Figure 10 A top view of the first wall of the housing provided in other embodiments of this application is shown. Figure 11 A cross-sectional view of the first wall of the housing provided in other embodiments of this application is shown. Figure 12 It shows Figure 11 A magnified schematic diagram of the structure at point B in the middle. Figure 13 An axial view of the first wall of the housing provided in some embodiments of this application is shown.

[0133] Please see Figures 3 to 13 This application provides a battery cell, and in this embodiment, a prismatic battery cell is used as an example for illustration.

[0134] like Figure 3 and Figure 4 The battery cell 1100 includes a housing 100, the housing 100 includes a first wall 110 and a second wall 120, the first wall 110 includes a wall body 111 and a pressure relief part 112, and the second wall 120 is welded to the first wall 110.

[0135] It should be noted that the battery cell 1100 provided in this application embodiment has a split-structure design for its casing 100, consisting of a casing body and an end cap. The end cap serves as the first wall 110, integrating a wall body 111 and a pressure relief section 112; the wall body 111 is the main load-bearing structure of the end cap. The casing body serves as the second wall 120, tightly connected to the end cap to form a closed cavity to accommodate components such as the battery cell assembly. The first wall 110 and the second wall 120 cooperate in terms of material properties and structural design to jointly constitute the safety protection system of the battery cell 1100, ensuring the stable operation of the battery cell 1100 during charging and discharging.

[0136] In some embodiments, the first wall 110 can be a stamped plate, and the wall body 111 and the pressure relief part 112 can be integrally formed. The pressure relief part 112 and the wall body 111 can be formed in one step through processes such as stamping, forging, or injection molding; this embodiment is not limited to this. This helps reduce the welding process between the pressure relief part 112 and the wall body 111, simplifying the production process, reducing pre-welding preparation and post-welding inspection work, and improving production efficiency. It also reduces performance inconsistencies caused by differences in welding processes, ensuring the quality of the battery cell 1100. Furthermore, it helps reduce problems caused by welding processes, such as welding defects, thereby reducing the failure probability of the pressure relief part 112 and improving the reliability of the battery cell 1100.

[0137] like Figure 9 and Figure 12 Along the thickness direction of the wall body 111, the minimum thickness h1 of the wall body 111 is greater than the maximum thickness h2 of the pressure relief part 112. The one-piece molding process can precisely control the minimum thickness h1 of the wall body 111 and the maximum thickness h2 of the pressure relief part 112 through the mold.

[0138] It should be noted that the minimum thickness h1 of the wall body 111 refers to the minimum thickness value among all positions on the wall body 111 along the thickness direction, i.e., the direction perpendicular to the surface of the wall body 111. For example, if the wall body 111 is a regular flat plate structure with uniform thickness, then h1 is the fixed thickness of the wall body 111; if the wall body 111 is an irregular structure, then h1 is the thickness of its thinnest point. The maximum thickness h2 of the pressure relief part 112 refers to the maximum thickness value among all positions on the pressure relief part 112 along the thickness direction.

[0139] It should be noted that the design logic for the minimum thickness h1 of the wall body 111 being greater than the maximum thickness h2 of the pressure relief part 112 is as follows: if the minimum thickness of the wall body 111 is less than the maximum thickness of the pressure relief part 112, the strength of the pressure relief part 112 may be higher than that of the wall body 111, which may prevent the pressure relief function from being properly activated when the pressure is released, potentially causing the casing 100 to crack and reducing the reliability of the battery cell 1100.

[0140] In some embodiments, when measuring the minimum thickness h1 of the wall body 111, the location of the thinnest point can be determined by three-dimensional scanning or multi-point measurement. For example, a laser scanner can be used to perform a grid scan along the surface of the wall body 111 to generate a thickness cloud map and mark the minimum thickness point. When measuring the maximum thickness h2 of the pressure relief part 112, since the pressure relief part 112 is usually a non-planar structure such as a groove or a notch, the thickness at the bottom of the notch can be measured using a laser confocal microscope. This embodiment does not limit this.

[0141] Therefore, by setting the minimum thickness h1 of the wall body 111 to be greater than the maximum thickness h2 of the pressure relief part 112, since the thickness of the pressure relief part 112 is relatively small, when the internal pressure of the battery reaches a certain value, the pressure relief part 112 will open first to relieve pressure, thereby improving the controllability and accuracy of the pressure relief process and reducing the risk of battery rupture due to excessive pressure. Furthermore, since the thickness of the wall body 111 is relatively large, it can provide stable support for the entire battery structure during normal battery operation and pressure relief, reducing structural deformation or damage caused by pressure fluctuations and improving the reliability of the battery cell 1100.

[0142] Since the pressure relief part 112 is integrally formed by stamping, in order to reduce the stamping difficulty of the pressure relief part 112 while ensuring the structural strength of the housing 100, in some embodiments, the Vickers hardness of the first wall 110 is less than that of the second wall 120.

[0143] Vickers hardness is an index that measures the hardness of a material by indentation. Its core principle is: a diamond indenter in the shape of a square pyramid with a vertex angle of 136° is pressed vertically into the surface of the material under a certain test force, held for a specified time, and then the test force is removed. The hardness of the material is calculated by measuring the length of the diagonal of the indentation.

[0144] In the stamping design of the pressure relief section 112, the first wall 110 has a low Vickers hardness, that is, the first wall 110 is made of a material with a low Vickers hardness, which usually has better plasticity and is more likely to undergo plastic deformation during stamping, reducing the processing difficulty and helping to form a precise pressure relief structure; the second wall 120, as the main body of the shell 100, bears the internal pressure and external load. The higher Vickers hardness can improve the material's resistance to deformation, which helps to ensure the overall strength and prevent the shell 100 from deforming or breaking.

[0145] Therefore, by setting the Vickers hardness of the first wall 110 to be less than that of the second wall 120, while maintaining the structural strength of the shell 100, it helps to further reduce the stamping difficulty of the pressure relief part 112 and improve the stamping effect of the pressure relief part 112.

[0146] It should be noted that during the cyclic charging and discharging process, the battery cell assembly undergoes hard expansion, leading to leakage. To further adapt to the high expansion force of high-energy-density cells and achieve higher unit energy density and gravimetric energy density in the cell assembly, thus reducing leakage, the tensile strength of the casing 100 can be set higher in this embodiment. Specifically, in this embodiment, the tensile strength e of the first wall 110 can satisfy the condition: 240MPa≤e≤1000MPa, and the tensile strength f of the second wall 120 can satisfy the condition: 240MPa≤e≤1000MPa.

[0147] In some embodiments, the tensile strength e of the first wall 110 can be 240 MPa, 340 MPa, 440 MPa, 500 MPa, 550 MPa, 580 MPa, 600 MPa, 1000 MPa, or any value between 240 MPa and 1000 MPa. This embodiment does not limit this. The tensile strength f of the second wall 120 can be 240 MPa, 340 MPa, 440 MPa, 500 MPa, 550 MPa, 580 MPa, 600 MPa, 700 MPa, 800 MPa, 900 MPa, 1000 MPa, or any value between 240 MPa and 600 MPa. This embodiment does not limit this.

[0148] By setting the tensile strength of both the first wall 110 and the second wall 120 within the range of 240MPa to 1000MPa, this application increases the tensile strength of the housing 100. The housing 100 has a higher tensile strength. Compared with the aluminum-cased explosion-proof valve in the related technology, the housing 100 with higher tensile strength in this application helps to adapt to the high expansion force of high-energy-density cells, thereby withstanding the internal expansion force generated by high-energy-density cells during charging and discharging, reducing the risk of deformation or cracking of the housing 100, and improving the reliability of the battery cell. At the same time, under the background of high tensile strength, the molding difficulty of the explosion-proof valve is higher.

[0149] Tensile strength refers to the maximum ability of a material to resist fracture under axial load. It reflects the maximum stress a material can withstand during tension. When the external force reaches the tensile strength, the material will fracture due to local shrinkage. A tensile testing machine can be used to apply axial tension to the specimen, record the data from deformation to fracture, plot a stress-strain curve, and find the stress value corresponding to the highest point of the curve, which is the tensile strength.

[0150] In some embodiments, to further adapt to the high expansion force of high-energy-density battery cells and withstand the internal expansion force generated during charging and discharging, thereby reducing the risk of deformation or cracking of the casing 100 and reducing battery cell leakage, the casing 100 in this embodiment can be made of titanium or steel. Specifically, the second wall 120 can be made of TA1, TA4G, TC4, or other high-strength titanium materials modified with titanium, and the first wall 110 can be made of pure titanium low-strength materials such as TA1 or TA2. Among them, TA1 or TA2 are industrial pure titanium with high titanium content and few impurities; TA4G is a modified material based on TA4, which further improves the material strength; TC4 is an α+β type titanium alloy with high strength and good corrosion resistance, which can effectively ensure the structural strength when used for the casing 100. Therefore, by using a titanium or steel shell, the shell 100 has higher strength, and it has the advantages of a high-energy chemical system and lightweight and high strength. There is a tendency to use a thinner wall and higher strength shell 100, which helps to adapt to the high expansion force of high energy density cells and improve the reliability of battery cells. At the same time, with the use of a titanium or steel shell, the molding of the pressure relief part 112 is more difficult.

[0151] It should be noted that, given the use of titanium or steel shells in this application, the high mechanical strength of the titanium or steel shells results in higher tensile strength and fatigue resistance for the shell 100, enabling it to withstand pressure cycles without fatigue fracture. This also helps to accommodate the high expansion forces of high-energy-density battery cells. However, the high tensile strength also makes the molding of the pressure relief section 112 more difficult. Therefore, to reduce the molding difficulty of the pressure relief section 112, in this embodiment, the tensile strength of the first wall 110 is lower than that of the second wall 120, resulting in a lower tensile strength for the pressure relief section 112. When the internal pressure of the battery cell 1100 exceeds a threshold, the pressure relief section 112, acting as a pre-defined "weak link," preferentially ruptures or opens due to its lower tensile strength, guiding the pressure release direction to a pre-defined path.

[0152] In some embodiments, the minimum thickness h1 of the wall body 111 and the maximum thickness h2 of the pressure relief part 112 can satisfy the condition: 0.08h1≤h2≤0.3h1.

[0153] In some embodiments, the ratio of the maximum thickness h2 of the pressure relief section 112 to the minimum thickness h1 of the wall body 111 can be 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3 or any value between 0.08 and 0.3.

[0154] If the maximum thickness h2 of the pressure relief section 112 is less than or equal to 0.08h1, the pressure relief section 112 may fail under normal conditions due to its excessive thinness; if the maximum thickness h2 of the pressure relief section 112 is greater than or equal to 0.3h1, the pressure relief section 112 has excessive strength and cannot open in a timely manner under abnormal pressure. Therefore, by setting the maximum thickness h2 of the pressure relief section 112 to be greater than or equal to 0.08h1, the risk of processing difficulties or accidental breakage caused by the pressure relief section 112 being too thin is reduced; by setting the maximum thickness h2 of the pressure relief section 112 to be less than or equal to 0.3h1, it is ensured that the pressure relief section 112 is thin enough to break and open the pressure relief preferentially, while the wall body 111 maintains structural support.

[0155] In some embodiments, the minimum thickness h1 of the wall body 111 can satisfy the condition: 0.6mm≤h1≤1mm.

[0156] In some embodiments, the minimum thickness h1 of the wall body 111 can be set to 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, or any value between 0.6mm and 1mm, depending on actual needs. This embodiment does not limit this.

[0157] By setting the minimum thickness h1 of the wall body 111 between 0.6 mm and 1 mm, on the one hand, it helps ensure that the wall body 111 has sufficient mechanical strength, reducing the risk of plastic deformation or cracking of the battery cell 1100 during normal use, providing a stable support foundation for the pressure relief section 112, and reducing the risk of failure of the pressure relief section 112 due to the wall body 111 being too thin. On the other hand, it helps control the weight of the housing 100, reducing the excessive increase in the weight of the battery cell 1100.

[0158] In some embodiments, the maximum thickness h2 of the pressure relief section 112 can satisfy the condition: 0.04mm≤h2≤0.3mm.

[0159] In some embodiments, the maximum thickness h2 of the pressure relief portion 112 can be 0.04 mm, 0.05 mm, 0.06 mm, 0.08 mm, 0.1 mm, 0.2 mm, 0.25 mm, 0.3 mm, or any value between 0.04 mm and 0.3 mm.

[0160] By setting the maximum thickness h2 of the pressure relief section 112 between 0.04 mm and 0.3 mm, on the one hand, it helps to ensure that the pressure relief section 112 is thin enough to break first when the internal pressure of the battery reaches the safety threshold, reducing the problem of other areas of the casing 100 failing first; on the other hand, it helps to reduce the risk of excessive opening pressure caused by excessive thickness of the pressure relief section 112, and improve the reliability of the battery cell 1100.

[0161] Please see Figure 5 In some embodiments, the minimum thickness h1 of the wall body 111 is greater than or equal to the maximum wall thickness h3 of the second wall 120.

[0162] By setting the minimum thickness h1 of the wall body 111 to be greater than or equal to the maximum wall thickness h3 of the second wall 120, the wall body 111 can withstand higher mechanical loads, improving the reliability of the battery cell 1100. The second wall 120 can be appropriately thinned, which helps to reduce the overall weight of the casing 100 while still maintaining the necessary support function. At the same time, low-strength materials can be used to achieve the effect of casing 100 strength.

[0163] In some embodiments, the maximum wall thickness h3 of the second wall 120 can satisfy the condition: 0.1mm≤h3≤0.4mm.

[0164] In some embodiments, the maximum wall thickness h3 of the second wall 120 can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or any value between 0.1 mm and 0.4 mm. This embodiment does not limit this.

[0165] By setting the maximum wall thickness h3 of the second wall 120 between 0.1 mm and 0.4 mm, on the one hand, it helps to ensure that the second wall 120 has sufficient mechanical support to prevent deformation during battery assembly or transportation; on the other hand, it can effectively control the weight of the housing 100.

[0166] In some embodiments, the Vickers hardness of the first wall 110 is a, and the Vickers hardness of the second wall 120 is b, where a and b satisfy the condition: a≤b.

[0167] By setting the Vickers hardness of the first wall 110 to be less than or equal to the Vickers hardness of the second wall 120, the lower hardness of the first wall 110 makes it easier to stamp the pressure relief part 112 and ensures that the pressure relief part 112 can break preferentially, providing moderate plastic deformation capacity and absorbing impact energy; the higher hardness of the second wall 120 helps to maintain the overall rigidity of the shell 100 and resist external mechanical impact.

[0168] In some embodiments, the Vickers hardness α of the first wall 110 can satisfy the condition: 100MPa≤a≤250MPa.

[0169] In some embodiments, the Vickers hardness α of the first wall 110 can be 100 MPa, 150 MPa, 180 MPa, 200 MPa, 250 MPa, or any value between 100 MPa and 250 MPa. This embodiment does not limit this.

[0170] By setting the Vickers hardness a of the first wall 110 to between 100 MPa and 250 MPa, on the one hand, it helps to ensure the basic structural strength of the first wall 110 and maintain the morphological stability of the pressure relief part 112; on the other hand, it helps to maintain sufficient plasticity to ensure controllable fracture in the event of thermal runaway.

[0171] In some embodiments, the Vickers hardness b of the second wall 120 can satisfy the condition: 100MPa≤b≤380MPa.

[0172] In some embodiments, the Vickers hardness b of the second wall 120 can be 100 MPa, 150 MPa, 180 MPa, 200 MPa, 250 MPa, 300 MPa, 380 MPa, or any value between 100 MPa and 380 MPa. This embodiment does not limit this.

[0173] By setting the Vickers hardness b of the second wall 120 between 100MPa and 380MPa, it helps to ensure basic resistance to deformation, while also being able to withstand higher mechanical impacts, thus improving the reliability of the battery cell 1100.

[0174] In some embodiments, the yield strength of the first wall 110 is c, and the yield strength of the second wall 120 is d, where c and d satisfy the condition: c≤d.

[0175] It should be noted that yield strength refers to the minimum stress value when a material undergoes plastic deformation under the action of external force. It marks the critical point when a material transitions from the elastic deformation stage (deformation is fully restored after the external force is removed) to the plastic deformation stage (residual permanent deformation after the external force is removed).

[0176] The method for testing yield strength can include tensile testing. The principle is to apply an axial tensile load to the specimen, record the stress-strain curve, and determine the stress value at which the material yields. The testing steps include: preparing the specimen, machining it to a standard shape according to standards, ensuring a smooth and defect-free surface; clamping the specimen in the fixture of a tensile testing machine, ensuring the axis is aligned with the load direction, loading at a constant rate, and simultaneously recording load-displacement data; determining the yield strength. A yield plateau appears on the curve (the strain continues to increase without an increase in load), and the corresponding stresses are the upper yield strength (the maximum stress at the first drop) and the lower yield strength (the average stress during the plateau phase). The lower yield strength is usually taken as the material's yield strength.

[0177] By setting a lower yield strength c for the first wall 110, making it a weak point in the casing 100, when the internal pressure of the battery abnormally increases, the first wall 110 will preferentially reach its yield strength and crack along a preset pressure relief path, releasing the internal pressure and preventing the battery from rupturing due to excessive pressure. By setting a higher yield strength d for the second wall 120, it helps ensure that the casing 100 maintains its integrity before the first wall 110 is depressurized, improving the reliability of the battery cell 1100.

[0178] In some embodiments, the yield strength c of the first wall 110 can satisfy the condition: 140MPa≤c≤500MPa.

[0179] In some embodiments, the yield strength c of the first wall 110 can be 140 MPa, 200 MPa, 280 MPa, 300 MPa, 350 MPa, 400 MPa, 500 MPa, or any value between 140 MPa and 140 MPa. This embodiment does not limit this.

[0180] If the yield strength c of the first wall 110 is less than 140 MPa, plastic indentation may occur due to insufficient yield strength, posing a risk of seal failure. If the yield strength c of the first wall 110 is greater than 500 MPa, the mold will bear excessive pressure when stamping the pressure relief part 112, reducing the mold's service life and increasing processing costs. Therefore, setting the yield strength c of the first wall 110 between 140 MPa and 500 MPa helps ensure the structural integrity of the housing 100 and enables it to withstand higher mechanical impacts.

[0181] In some embodiments, the yield strength d of the second wall 120 satisfies the condition: 140MPa≤d≤1000MPa.

[0182] In some embodiments, the yield strength d of the second wall 120 can be 140 MPa, 200 MPa, 280 MPa, 300 MPa, 350 MPa, 400 MPa, 500 MPa, 600 MPa, 700 MPa, 800 MPa, 900 MPa, 1000 MPa, or any value between 140 MPa and 1000 MPa. This embodiment does not limit this.

[0183] By setting the yield strength d of the second wall 120 between 140MPa and 1000MPa, on the one hand, the structural strength of the second wall 120 is effectively ensured, thereby providing effective support for the first wall 110; on the other hand, the strength of the second wall 120 is kept within a suitable range, reducing the problem that the shell 100 is too rigid due to excessive strength, and the first wall 110 cannot deform and absorb energy well.

[0184] In some embodiments, the tensile strength e of the first wall 110 can satisfy the condition: 240MPa≤e≤600MPa.

[0185] In some embodiments, the tensile strength e of the first wall 110 can be 240 MPa, 340 MPa, 440 MPa, 500 MPa, 550 MPa, 580 MPa, 600 MPa, or any value between 240 MPa and 600 MPa. This embodiment does not limit this.

[0186] If the tensile strength e of the first wall 110 is less than 240 MPa, the insufficient tensile strength may lead to premature plastic deformation or fracture, resulting in unnecessary pressure relief. If the tensile strength e of the first wall 110 is greater than 600 MPa, the excessive strength makes it difficult for the first wall 110 to open under the preset pressure threshold, causing continuous pressure accumulation inside the battery. Therefore, by setting the tensile strength e of the first wall 110 between 240 MPa and 600 MPa, pressure relief can be initiated promptly and stably, effectively preventing continuous pressure rise from damaging the battery. At the same time, the reasonable strength allows the first wall 110 to maintain a controllable rupture mode during pressure relief, avoiding the generation of dangerous fragments and minimizing safety risks.

[0187] In some embodiments, the material of the second wall 120 may include a titanium alloy, and the material of the first wall 110 may include a titanium alloy; the Ti content in the first wall 110 is greater than or equal to the Ti content in the second wall 120.

[0188] It should be noted that the first wall 110, as a key component for pressure relief, has a higher Ti content, resulting in higher purity of the titanium alloy and relatively lower impurity element content. This helps reduce material strength and improve plasticity, ensuring that the pressure relief section 112 can reliably open under the preset pressure. The second wall 120 mainly bears the structural load-bearing function. Its relatively low Ti content can be strengthened by adding alloying elements to improve the yield strength and hardness of the second wall 120, ensuring the stability of the main structure of the shell 100.

[0189] By setting a higher Ti content in the first wall 110, the material is closer to the properties of pure titanium, with better plasticity and toughness, but lower strength, making the first wall 110 more prone to plastic deformation under impact load. By setting a lower Ti content in the second wall 120, the yield strength and rigidity of the second wall 120 can be significantly improved, enabling it to maintain its structural support capacity during impact.

[0190] In some embodiments, the Ti content in the second wall 120 can be 80%-99.6%.

[0191] In some embodiments, the Ti content in the second wall 120 can be 80%, 85%, 90%, 92%, 94%, 98%, 99.6%, or any value between 80% and 99.6%. This embodiment does not limit this.

[0192] By setting the Ti content in the second wall 120 to between 80% and 99.6%, on the one hand, the risk of the second wall 120 being prone to fracture under impact load is reduced; on the other hand, it helps to reduce the problem that the second wall 120 cannot provide effective support for the first wall 110 when its strength is too low.

[0193] In some embodiments, the Ti content in the first wall 110 can be 90%-99.6%.

[0194] In some embodiments, the Ti content in the first wall 110 can be 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99.6%, or any value between 90% and 99.6%. This embodiment does not limit this. By setting the Ti content in the first wall 110 to 90%-99.6%, the plasticity and toughness are better, but the strength is lower, making the first wall 110 more prone to plastic deformation under impact loads.

[0195] In some embodiments, the pressure relief portion 112 may be a groove formed by stamping on the wall body 111.

[0196] It should be noted that the scoring groove reduces the local thickness and forms a stress concentration area by stamping grooves or textures on the surface of the wall body 111. When the internal pressure of the battery increases, the scoring groove will first reach the material yield strength, thereby causing directional cracking and achieving controllable pressure relief.

[0197] By setting the pressure relief part 112 as a groove formed by stamping the wall body 111, the groove and the wall body 111 are integrally formed structures without welding or assembly interfaces, reducing the risk of pressure relief failure caused by leakage at the connection parts and improving the overall sealing performance of the shell 100.

[0198] In some of these embodiments, such as Figure 6 and Figure 7 The extension direction of the pressure relief part 112 can be parallel to that of the wall body 111, so that the stress in the wall body 111 is evenly distributed along the extension direction, reducing unexpected cracking caused by local stress concentration.

[0199] In some of these embodiments, such as Figure 8 and Figure 9 The minimum distance h4 between the surface of the pressure relief part 112 near the second wall 120 and the surface of the wall body 111 near the second wall 120 is greater than 0; or, the minimum distance h5 between the surface of the pressure relief part 112 away from the second wall 120 and the surface of the wall body 111 away from the second wall 120 is greater than 0.

[0200] By setting the distance between the pressure relief part 112 and both the inner and outer sides to be greater than 0, it is ensured that the pressure relief part 112 does not completely penetrate the wall body 111, which can prevent the pressure relief part 112 from cracking or leaking prematurely due to excessive thinning under normal operating conditions, thereby improving the reliability of the battery cell 1100.

[0201] In some of these embodiments, such as Figure 10 and Figure 11The extension direction of the pressure relief section 112 may form an angle with the wall body 111. The value of the angle is not limited and can be set according to actual needs.

[0202] By setting the extension direction of the pressure relief section 112 to have an angle with the wall body 111, the presence of the angle can change the direction of crack propagation during pressure relief, reduce the risk of cracks extending vertically along the thickness direction of the wall body 111, and the reaction force generated when the high-pressure gas is ejected can guide the airflow to deflect in a specific direction, while reducing the direct impact of the pressure relief airflow on the internal structure of the battery or adjacent battery cells 1100, thereby reducing the risk of thermal runaway.

[0203] In some of these embodiments, such as Figure 11 and Figure 12 The pressure relief section 112 may include at least one bent section 1121. The number and shape of the bent sections 1121 are not limited and can be flexibly arranged according to the shape and internal structure of the battery casing 100.

[0204] It should be noted that the bent portion 1121 can be formed by processes such as stamping and rolling. Only a punch or roller needs to be set in the mold to achieve high-precision bending angle control, and no additional processing steps are required.

[0205] By providing a pressure relief section 112 including at least one bending section 1121, this section is more prone to plastic deformation or cracking under the same pressure, gradually releasing internal pressure and reducing the risk of the shell 100 bursting due to instantaneous high pressure.

[0206] In some of these embodiments, such as Figure 12 The pressure relief section 112 may include at least two connecting plates 11211 connected sequentially and arranged at an angle, with two adjacent connecting plates 11211 forming a bend 1121. When the internal pressure of the battery increases, these stress concentration areas will preferentially reach the yield strength of the material and trigger fracture. By adjusting the number, angle, and connection method of the connecting plates 11211, the pressure relief trigger pressure can be precisely controlled. Compared with a straight pressure relief section, the trigger pressure can be reduced, ensuring pressure relief at a lower pressure and reducing the problems of accidental or delayed pressure relief caused by pressure fluctuations.

[0207] In some of these embodiments, such as Figure 6 and Figure 13 Along the thickness direction perpendicular to the first wall 110, the shape of the groove can include any one of racetrack shape, circle or multi-branch intersection shape.

[0208] It should be noted that the implementation process of the runway-shaped notch groove is as follows: stamping die forming is adopted. The punch and die of the die are designed with a runway-shaped profile. During stamping, the punch presses down to locally thin the material of the wall body to form a notch. By adjusting the die gap and stamping pressure, the notch depth can be precisely controlled. The circular notch groove can be directly formed by a stamping die or can be formed by laser processing to ablate the material to form a circular groove. The multi-branch cross shape can be the shape of "king" or the shape of "worker". This embodiment does not limit this.

[0209] By setting notch grooves of various different shapes, precise control of the pressure relief function can be achieved according to the battery shape, application scenario and safety requirements, maximizing the adaptation to the process cost while ensuring reliability.

[0210] In some of these embodiments, the pressure relief part 112 can be arched or can be a planar notch. This embodiment does not limit this.

[0211] In some of these embodiments, the housing 100 includes an electrode terminal 200, and the electrode terminal 200 is arranged on the third wall 130 opposite to the first wall 110. By arranging the electrode terminal 200 on the third wall 130 opposite to the first wall 110, the first wall 110 and the electrode terminal 200 are located on both sides of the housing 100, which helps to prevent the high-temperature jet from directly impacting the electrode terminal 200 during pressure relief, reducing the short-circuit risk and improving the reliability of the battery cell. Among them, the end cover in the embodiment of the present application serves as the third wall 130.

[0212] The battery cell 1100 provided in this application embodiment includes: a housing 100, which adopts a split structure design and consists of a shell body and an end cap. The housing 100 includes a first wall 110 and a second wall 120, with the end cap serving as the first wall 110 and the shell body serving as the second wall 120, and is tightly connected to the end cap. The first wall 110 includes a wall body 111 and a pressure relief portion 112. The wall body 111 and the pressure relief portion 112 can be integrally formed by processes such as stamping, forging, or injection molding. Along the thickness direction of the wall body 111, the minimum thickness h1 of the wall body 111 is greater than the maximum thickness h2 of the pressure relief portion 112. Specifically, the minimum thickness h1 of the wall body 111 and the maximum thickness h2 of the pressure relief portion 112 can satisfy the condition: 0.08h1≤h2≤0.3h1. The following conditions must be met: 0.6mm ≤ h1 ≤ 1mm; the maximum thickness h2 of the pressure relief section 112 must meet: 0.04mm ≤ h2 ≤ 0.3mm. In this embodiment, the Vickers hardness of the first wall 110 is less than or equal to the Vickers hardness of the second wall 120. Specifically, the Vickers hardness a of the first wall 110 must meet: 100MPa ≤ a ≤ 250MPa; and the Vickers hardness b of the second wall 120 must meet: 100MPa ≤ b ≤ 380MPa. The shell 100 is made of titanium or steel. Specifically, the first wall 110 can be a structural component made of TA1 or TA2, and the second wall 120 can be a structural component made of any one of TA1, TA4G, or TC4. The tensile strength e of the first wall 110 must meet: 240MPa ≤ e ≤ 1000MPa; and the tensile strength f of the second wall 120 must meet: 240MPa ≤ e ≤ 1000MPa.

[0213] When the battery cell 1100 provided in this application embodiment is manufactured by integrally molding the wall body 111 and the pressure relief part 112, it helps to reduce the welding process between the pressure relief part 112 and the wall body 111, simplifying the production process. By setting the minimum thickness of the wall body 111 to be greater than the maximum thickness of the pressure relief part 112, since the thickness of the pressure relief part 112 is relatively small, when the internal pressure of the battery reaches a certain value, the pressure relief part 112 will open to release pressure first, improving the controllability and accuracy of the pressure relief process and reducing the risk of battery rupture due to excessive pressure; and since the thickness of the wall body 111 is relatively large, it can provide stable support for the entire battery structure during normal battery operation and pressure relief, reducing structural deformation or damage caused by pressure fluctuations and improving the reliability of the battery cell 1100. By setting the Vickers hardness of the first wall 110 to be less than that of the second wall 120, while maintaining the structural strength of the shell 100, it helps to further reduce the stamping difficulty of the pressure relief part 112 and improve the stamping effect of the pressure relief part 112. By setting the tensile strength of both the first wall 110 and the second wall 120 within the range of 240MPa to 1000MPa, this application increases the tensile strength of the casing 100. The casing 100 has a higher tensile strength, which, compared to aluminum-cased explosion-proof valves in related technologies, helps to accommodate the high expansion force of high-energy-density cells, thereby withstanding the internal expansion force generated by the high-energy-density cells during charging and discharging, reducing the risk of casing 100 deformation or breakage, and improving the reliability of the battery cell. However, with higher tensile strength, the molding of the explosion-proof valve is more difficult. Using a titanium or steel casing results in higher strength for the casing 100, which possesses the advantages of a high-energy chemical system and lightweight yet high strength. This leads to a tendency to use thinner-walled and higher-strength casings 100, which helps to accommodate the high expansion force of high-energy-density cells and improve the reliability of the battery cell. However, with titanium or steel casings, the molding of the explosion-proof valve is more difficult.

[0214] This application also provides a method for preparing a single battery cell, comprising:

[0215] A housing may be provided, which may include a connected first wall and a second wall;

[0216] The first wall includes a wall body and a pressure relief part integrally formed with the wall body; along the thickness direction of the wall body, the minimum thickness h1 of the wall body is greater than the maximum thickness h2 of the pressure relief part, and the Vickers hardness of the first wall is less than that of the second wall.

[0217] In some embodiments, the wall body 111 and the pressure relief part 112 can be integrally formed by stamping or injection molding. The minimum thickness h1 of the wall body 111 can be set to 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, or any value between 0.6mm and 1mm, depending on actual needs. The maximum thickness h2 of the pressure relief part 112 can be 0.04mm, 0.05mm, 0.06mm, 0.08mm, 0.1mm, 0.2mm, 0.25mm, 0.3mm, or any value between 0.04mm and 0.3mm.

[0218] In some embodiments, the Vickers hardness of the first wall 110 can be 100 MPa, 150 MPa, 180 MPa, 200 MPa, 250 MPa, or any value between 100 MPa and 250 MPa, and the Vickers hardness b of the second wall 120 can be 100 MPa, 150 MPa, 180 MPa, 200 MPa, 250 MPa, 300 MPa, 380 MPa, or any value between 100 MPa and 380 MPa. The first wall 110 with lower Vickers hardness preferentially undergoes plastic deformation, ensuring that the pressure relief section 112 actively opens during overpressure. The second wall 120 with higher Vickers hardness maintains the overall rigidity of the casing 100, preventing the casing 100 from cracking during pressure relief and improving the reliability of the battery cell 1100.

[0219] It should be noted that the battery cell 1100 prepared by the above method has a synergistic design of thickness and Vickers hardness, which can effectively reduce the risk of accidental or delayed pressure release. At the same time, the integrity of the casing 100 can be maintained during the pressure release process to prevent the internal high temperature and high pressure from spreading to adjacent battery cells 1100.

[0220] In some embodiments, prior to the step of providing the first wall, the preparation method further includes:

[0221] The wall body is stamped to form grooves, which serve as pressure relief sections.

[0222] In some embodiments, the first wall 110 is a stamping plate. Through precise mold design and pressure control, grooves can be quickly and accurately processed on the wall body 111. In one stamping stroke, the wall body 111 can be thinned to form grooves of the required shape, such as racetrack or circle, with high processing efficiency.

[0223] By using the above method to prepare the pressure relief part 112, the groove and the wall body 111 are integrated structures, without weak links such as welding and bonding, simplifying the production process, reducing the preparation work before welding and the inspection work after welding, and improving production efficiency; at the same time, it also reduces the performance inconsistency problem caused by differences in welding process, and ensures the quality of battery cell 1100.

[0224] In some embodiments, the step of stamping the grooves on the wall body specifically includes:

[0225] An initial groove is formed by stamping on the wall body 111;

[0226] The initial groove is thinned to form a scoring groove.

[0227] In this embodiment, the stamping process of the scoring groove is decomposed into two steps: "forming the initial groove" and "thinning treatment". Specifically, the first step, stamping to form the initial groove, mainly serves to determine the position, shape, and basic outline of the scoring groove. At this stage, the groove depth is relatively shallow, and the material only undergoes localized plastic deformation, which helps reduce the risk of excessive stress concentration caused by excessive stamping in one go, leading to cracks or deformation in the wall body 111. The second step involves thinning the initial groove through secondary stamping or rolling, gradually processing the groove depth to the design value. This process is carried out on the basis of the material having been initially formed, which can make the stress distribution more uniform and help prevent tearing or springback caused by sudden changes in thickness, ensuring a smooth edge of the scoring groove.

[0228] Therefore, by using a staged stamping process of initial groove and thinning to prepare the scoring groove, the reliability of the process and the product can be improved, while helping to reduce mold wear and production costs, and reducing the risk of mold wear or material cracking caused by one-time stamping.

[0229] In some embodiments, the step of thinning the initial groove to form a scoring groove specifically includes:

[0230] The maximum thickness h2 of the pressure relief section at the location of the control groove satisfies the condition: 0.04mm ≤ h2 ≤ 0.3mm. In some embodiments, the maximum thickness h2 of the pressure relief section can be set to 0.04mm, 0.05mm, 0.06mm, 0.08mm, 0.1mm, 0.2mm, 0.25mm, 0.3mm, or any value between 0.04mm and 0.3mm, depending on actual needs.

[0231] If h2 ≤ 0.04 mm, the excessive thickness may cause accidental pressure release under normal conditions; if h2 ≥ 0.3 mm, the excessive thickness of the pressure relief section 112 may prevent timely activation under abnormal high pressure. Therefore, by controlling the maximum thickness h2 of the pressure relief section 112 at the groove location to meet the condition: 0.04 mm ≤ h2 ≤ 0.3 mm, the trigger pressure can be controlled within a safe range, improving the reliability of the battery cell 1100.

[0232] In some embodiments, it may also include;

[0233] The minimum thickness h1 of the control wall body satisfies the condition: 0.6mm≤h1≤1mm.

[0234] In some embodiments, the minimum thickness h1 of the wall body 111 can be set to 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm or any value between 0.6mm and 1mm, depending on actual needs.

[0235] By controlling the minimum thickness h1 of the wall body 111 to be between 0.6 mm and 1 mm, on the one hand, it helps ensure that the wall body 111 has sufficient mechanical strength, reducing the risk of plastic deformation or cracking of the battery cell 1100 during normal use, providing a stable support foundation for the pressure relief section 112, and reducing the risk of failure of the pressure relief section 112 due to the wall body 111 being too thin. On the other hand, it helps control the weight of the housing 100, reducing the excessive increase in the weight of the battery cell 1100.

[0236] The battery performance of the embodiments and comparative examples was tested below with relevant parameters. Specific values ​​are detailed in Tables 1, 2 and 3.

[0237] Table 1: Influence of wall thickness and pressure relief section thickness on the pressure relief effect of battery cells

[0238]

[0239] As shown in Table 1, the thickness of the wall body 111 and the pressure relief part 112 has a certain impact on the pressure relief effect. In Examples 1, 2, and 3, the thickness h2 of the pressure relief part 112 is less than the thickness h1 of the wall body 111, and the pressure relief part 112 opens first to release pressure in a directional manner. In the comparative example, if the thickness h2 of the pressure relief part 112 is greater than the thickness h1 of the wall body 111, that is, the wall body 111 is thinner, then if the internal pressure of the battery is too high, the wall body 111 may break first, causing the pressure relief effect to become uncontrolled.

[0240] Table 2: Influence of Vickers hardness of the first wall and Vickers hardness of the second wall on the stamping effect of the pressure relief section

[0241]

[0242] As shown in Table 2, the Vickers hardness of the first wall 110 and the second wall 120 has a certain impact on the stamping effect. In Examples 1, 2, and 3, the Vickers hardness of the first wall 110 is less than or equal to the Vickers hardness of the second wall 120. With a lower Vickers hardness, the pressure relief section 112 can be stamped normally without damaging the stamping die. In the comparative example, because the Vickers hardness of the first wall 110 is higher, a larger stamping force is required, which may lead to damage to the stamping die or cracking of the first wall 110.

[0243] Table 3: Influence of the tensile strength of the first wall and the tensile strength of the second wall on the forming effect of the pressure relief section

[0244]

[0245] As shown in Table 3, the tensile strength of the first wall 110 has a certain impact on the molding effect. In Examples 1, 2 and 3, the tensile strength e of the first wall 110 is less than the tensile strength f of the second wall 120. Thus, the lower tensile strength of the first wall 110 results in a better molding effect for the pressure relief part 112 and does not damage the stamping die. Meanwhile, in Examples 1, 2 and 3, the tensile strength of the second wall 120 can be set to be larger, which helps to ensure the mechanical strength of the shell 100 and improve its ability to withstand mechanical loads and internal pressure.

[0246] Please see Figure 2 This application also provides a battery device, including a housing and a battery cell 1100, wherein the battery cell 1100 is housed in the housing.

[0247] When the battery cell 1100 provided in this application embodiment is used, the pressure relief part 112 and the wall body 111 are integrally formed, which helps to reduce the welding process between the pressure relief part 112 and the wall body 111, simplify the production process, reduce the preparation work before welding and the inspection work after welding, and improve production efficiency. At the same time, it also reduces the performance inconsistency problem caused by the difference in welding process, ensuring the quality of the battery cell 1100. In addition, it helps to reduce the problems caused by the welding process, such as welding defects, thereby reducing the failure probability of the pressure relief part 112 and improving the reliability of the battery cell 1100. By setting the minimum thickness of the wall body 111 to be greater than the maximum thickness of the pressure relief part 112, since the thickness of the pressure relief part 112 is relatively small, when the internal pressure of the battery reaches a certain value, the pressure relief part 112 will open first to relieve pressure, improving the controllability and accuracy of the pressure relief process and reducing the risk of battery rupture due to excessive pressure. Furthermore, since the thickness of the wall body 111 is relatively large, it can provide stable support for the entire battery structure during normal battery operation and pressure relief, reducing structural deformation or damage caused by pressure fluctuations and improving the reliability of the battery cell 1100. By setting the Vickers hardness of the first wall 110 to be less than that of the second wall 120, the stamping difficulty of the pressure relief part 112 is further reduced and the stamping effect of the pressure relief part 112 is improved while maintaining the structural strength of the shell 100.

[0248] Please see Figure 1 This application provides an electrical device, including a battery device from any of the above embodiments, which is used to provide electrical energy to the electrical device.

[0249] When the electrical device provided in this application embodiment is in use, the battery device composed of the battery cells 1100 provided in this application embodiment provides electrical energy to the electrical device. Since the pressure relief part 112 and the wall body 111 are integrally formed, it helps to reduce the welding process between the pressure relief part 112 and the wall body 111, simplify the production process, reduce the preparation work before welding and the inspection work after welding, and improve production efficiency; at the same time, it also reduces the performance inconsistency problem caused by the difference in welding process, ensuring the quality of the battery cell 1100; in addition, it helps to reduce the problems caused by the welding process, such as welding defects, thereby reducing the failure probability of the pressure relief part 112 and improving the reliability of the battery cell 1100. By setting the minimum thickness of the wall body 111 to be greater than the maximum thickness of the pressure relief section 112, the pressure relief section 112 will preferentially open to relieve pressure when the internal pressure of the battery reaches a certain value, improving the controllability and accuracy of the pressure relief process and reducing the risk of battery rupture due to excessive pressure. Furthermore, the relatively large thickness of the wall body 111 provides stable support for the entire battery structure during normal battery operation and pressure relief, reducing structural deformation or damage caused by pressure fluctuations and improving the reliability of the battery cell 1100. By setting the Vickers hardness of the first wall 110 to be less than that of the second wall 120, the stamping difficulty of the pressure relief section 112 is further reduced while maintaining the structural strength of the casing 100, thus improving the stamping effect of the pressure relief section 112.

[0250] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: Housing (100), the housing (100) comprising: The first wall (110) includes a wall body (111) and a pressure relief part (112), the wall body (111) and the pressure relief part (112) are integrally formed, and the tensile strength e of the first wall (110) satisfies the condition: 240MPa≤e≤1000MPa; The second wall (120) is welded to the first wall (110), and the tensile strength f of the second wall (120) satisfies the condition: 240MPa≤e≤1000MPa; Along the thickness direction of the wall body (111), the minimum thickness h1 of the wall body (111) is greater than the maximum thickness h2 of the pressure relief part (112), and the Vickers hardness a of the first wall (110) is less than the Vickers hardness b of the second wall (120).

2. The battery cell according to claim 1, characterized in that, The minimum thickness h1 of the wall body (111) and the maximum thickness h2 of the pressure relief part (112) satisfy the following condition: 0.08h1≤h2≤0.3h1.

3. The battery cell according to claim 1, characterized in that, The minimum thickness h1 of the wall body (111) satisfies the following condition: 0.6mm≤h1≤1mm.

4. The battery cell according to claim 1, characterized in that, The maximum thickness h2 of the pressure relief section (112) satisfies the following condition: 0.04mm≤h2≤0.3mm.

5. The battery cell according to claim 1, characterized in that, The housing includes a body and an end cap, the end cap being connected to the body, the end cap serving as the first wall (110), and the body serving as the second wall (120). The minimum thickness h1 of the first wall (110) is greater than or equal to the maximum wall thickness h3 of the second wall (120).

6. The battery cell according to claim 5, characterized in that, The maximum wall thickness h3 of the second wall (120) satisfies the following condition: 0.1mm≤h3≤0.4mm.

7. The battery cell according to any one of claims 1-6, characterized in that, The Vickers hardness α of the first wall (110) satisfies the following condition: 100MPa≤a≤250MPa.

8. The battery cell according to any one of claims 1-6, characterized in that, The Vickers hardness b of the second wall (120) satisfies the following condition: 100MPa≤b≤380MPa.

9. The battery cell according to any one of claims 1-6, characterized in that, The yield strength of the first wall (110) is c, and the yield strength of the second wall (120) is d. c and d satisfy the following condition: c≤d.

10. The battery cell according to claim 9, characterized in that, The yield strength c of the first wall (110) satisfies the following condition: 140MPa≤c≤500MPa.

11. The battery cell according to claim 9, characterized in that, The yield strength d of the second wall (120) satisfies the following condition: 140MPa≤d≤1000MPa.

12. The battery cell according to any one of claims 1-6, characterized in that, The tensile strength e of the first wall (110) satisfies the following condition: 240MPa≤e≤600MPa.

13. The battery cell according to any one of claims 1-6, characterized in that, The pressure relief part (112) is a groove formed by stamping on the wall body (111).

14. The battery cell according to claim 13, characterized in that, The extension direction of the pressure relief section (112) forms an angle with the wall body (111); or The extension direction of the pressure relief section (112) is parallel to that of the wall body (111).

15. The battery cell according to claim 14, characterized in that, The minimum distance h4 between the surface of the pressure relief section (112) near the second wall (120) and the surface of the wall body (111) near the second wall (120) is greater than 0; and / or The minimum distance h5 between the surface of the pressure relief part (112) facing away from the second wall (120) and the surface of the wall body (111) facing away from the second wall (120) is greater than 0.

16. The battery cell according to claim 14, characterized in that, The pressure relief section (112) includes at least one bent section (1121).

17. The battery cell according to claim 16, characterized in that, The pressure relief section (112) includes at least two connecting plates (11211) connected in sequence and arranged at an included angle, and two adjacent connecting plates (11211) together form a bending section (1121).

18. The battery cell according to claim 13, characterized in that, Along the thickness direction perpendicular to the first wall (110), the shape of the groove includes any one of racetrack shape, circle or multi-branch intersection shape.

19. The battery cell according to any one of claims 1-6, characterized in that, The housing (100) includes electrode terminals (200) disposed on a third wall (130) opposite to the first wall (110).

20. The battery cell according to any one of claims 1-6, characterized in that, The housing (100) may be a titanium housing or a steel housing.

21. The battery cell according to claim 20, characterized in that, The first wall (110) is a structural component made of TA1 or TA2.

22. The battery cell according to claim 20, characterized in that, The second wall (120) is a structural component made of any one of TA1, TA4G or TC4.

23. The battery cell according to any one of claims 1-6, characterized in that, The battery cell is a prismatic battery.

24. A battery device, characterized in that, Includes the battery cell described in any one of claims 1-23.

25. An electrical appliance, characterized in that, Includes the battery device of claim 24, the battery device being used to provide electrical energy.

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