An electric core shell, an electric core cover plate, an electric core and an energy storage device

Abstract

The application discloses an electric core shell, an electric core cover plate, an electric core and an energy storage device, and relates to the technical field of electric cores. Specifically, the application comprises a shell, at least one convex strip and at least one concave strip, the inside of the shell is provided with a storage cavity for accommodating a pole group; the at least one convex strip and the at least one concave strip are staggered on the same side wall of the shell and extend along a first direction of the shell; the first direction is the length direction of the shell; wherein, when the pole group is assembled into the storage cavity, the concave strip abuts against the pole group inwardly, an exhaust passage is defined between the pole group and the convex strip, and the exhaust passage is communicated with both ends of the shell along the first direction. According to the application, an exhaust passage is naturally formed between the pole group and the convex strip, gas is limited by the position and flows along the hollow exhaust passage to the end of the shell quickly, the gas pressure relief efficiency in the electric core is improved, and the pole group is prevented from being pushed by the stagnant gas flow and moving.

Description

Technical Field

[0001] This application relates to the field of battery cell technology, and in particular to a battery cell casing, a battery cell cover plate, a battery cell, and an energy storage device. Background Technology

[0002] The battery cell casing is mainly used in electric vehicles and energy storage power stations. It serves as a sealed carrier to house the battery cell electrode assembly and electrolyte, and provides a stable space for internal electrochemical reactions. It also prevents external moisture and impurities from intruding, thereby ensuring the long cycle life and high energy density operation of the energy storage system.

[0003] In existing technologies, the packaging structure of traditional battery cells typically involves directly assembling wound or stacked electrode groups inside a metal casing that is open at one end. This ensures that the inner wall of the casing fits tightly against the outer surface of the electrode groups. Subsequently, a cover plate with an explosion-proof valve is welded to the top of the casing. The electrode groups occupy most of the space inside the battery cell casing, and the electrolyte fills the inside of the electrode groups and tiny gaps. The inner wall of the battery cell casing and the electrode groups rely on surface contact for radial restraint and support.

[0004] However, the aforementioned existing technology has the following shortcomings: Because the inner wall of the cell casing is in close contact with the outer surface of the electrode assembly, under conditions of thermal runaway, high-temperature and high-pressure gas will be generated inside the cell. The cell can only expel this gas by squeezing it upwards through the gaps between the electrode assembly layers, resulting in a sharp increase in the resistance to the high-temperature and high-pressure gas discharge and localized gas pressure overload. Furthermore, because the electrode assembly is close to the inner wall of the cell casing, a radial adhesion effect of the second sidewall is likely to occur. When the internal gas pressure of the cell rises sharply and gas discharge is not timely, the trapped airflow laterally squeezes the casing, causing the airflow to push the electrode assembly upwards. This results in bulging deformation of the casing sidewalls and the upper end of the moving electrode assembly abutting the top pressure relief area, blocking the final gas discharge path and further increasing the resistance to exhaust.

[0005] Therefore, this application aims to solve the problem of increased gas discharge resistance in existing battery cells under thermal runaway conditions, and also to solve the problem of untimely internal gas pressure discharge, which can easily lead to bulging of the casing sidewalls and electrode cross-movement blocking the discharge path. Summary of the Invention

[0006] The main purpose of this application is to provide a battery cell casing, a battery cell cover plate, a battery cell, and an energy storage device, which aims to solve the problem of increased gas exhaust resistance in existing battery cells under thermal runaway conditions, and also to solve the problem of untimely internal gas pressure discharge, which can easily lead to bulging of the casing sidewalls and electrode group movement blocking the discharge path.

[0007] To achieve the above objectives, this application proposes a battery cell casing, comprising: The housing has an internal cavity for accommodating the electrode assembly; At least one convex rib and at least one concave rib are alternately arranged on the same side wall of the housing and extend along a first direction of the housing; The first direction is the length direction of the shell; When the electrode assembly is assembled into the storage cavity, the concave strip abuts against the electrode assembly inward, and an exhaust channel is defined between the electrode assembly and the convex strip. The exhaust channel connects to both ends of the housing along the first direction.

[0008] Optionally, the housing is a square housing, which includes two opposing first sidewalls and two opposing second sidewalls; The outer surface width of the first sidewall is A0, and the outer surface width of the second sidewall is B0, where A0 is less than B0; The wall thickness of the shell is T1; The vertical depth of the recessed strip into the storage cavity is H, and the lateral width of the recessed strip along the outer surface of the first sidewall is W1. The dimensional parameters of the housing satisfy the following relationship: ; .

[0009] Optionally, the total cross-sectional area of ​​the exhaust passage defined between the first sidewall and the electrode group is S5, and the cross-sectional area of ​​the electrode group is S6. S5 and S6 satisfy the following relationship: .

[0010] Optionally, the inner walls on both sides of the concave strip are inclined relative to the reference plane of the first side wall, and form a taper N1, wherein, ; The transition between the concave strip and the convex strip is provided with a fillet R1, wherein... .

[0011] Optionally, the housing is provided with a weld that penetrates its wall thickness and extends along the first direction; The width of the weld is a, and it satisfies: .

[0012] Optionally, the housing is a one-piece hot-extruded molded part, and satisfies: ; Alternatively, the housing is a roll-formed, bent, and welded part, and satisfies the following: .

[0013] This application also discloses a cell cover plate, comprising: A metal plate has at least one convex edge and at least one concave edge arranged in an alternating manner at both ends along a third direction, the convex edge and the concave edge being used to assemble the end of the battery cell casing; An explosion-proof valve is mounted on the metal plate; An insulating plate is attached to one side of the metal plate; A protective part is connected to the insulating plate and is positioned opposite the explosion-proof valve. The side of the protective part facing the metal plate is recessed and together with the metal plate defines a protective groove. A flow hole communicating with the protective groove is provided on the protective part. A protective plate is disposed within the protective groove, with its side facing the explosion-proof valve abutting against the metal plate; the protective plate has through holes, allowing airflow to pass through the through holes and flow to the explosion-proof valve; the melting point of the protective plate is higher than that of the protective part; Wherein, the third direction is the length direction of the metal plate.

[0014] Optionally, the protective plate includes a substrate and bosses and counters disposed on the edge of the substrate in an alternating manner; The boss abuts against the side of the metal plate facing the protective groove; The platform is connected to the side of the protective part facing the metal plate.

[0015] Optionally, the substrate is rectangular with a length of A2 and a width of B2, and the area of ​​the substrate is... for: ; The effective opening area of ​​the explosion-proof valve is S0, the total projected area of ​​the boss and the countersunk platform on the substrate plane is S2, the total area of ​​the through holes is S3, and the cross-sectional area of ​​the flow channel between the protective plate and the metal plate is S4. Therefore:

[0016]

[0017] .

[0018] This application also discloses a battery cell, comprising: pole group; An insulating film is fitted onto the outer wall of the electrode assembly; The housing contains the electrode assembly carrying the insulating film, and the housing adopts the above-described cell outer shell; The first cover plate and the second cover plate are respectively assembled at the two open ends of the housing, and at least the first cover plate adopts the above-mentioned cell cover plate; Wherein, the convex edge on the first cover plate is installed at the end of the convex strip, and the concave edge on the first cover plate is installed at the end of the concave strip, so that the first cover plate is sealed and assembled with the end of the housing, and the exhaust channel is connected to the first cover plate.

[0019] This application also discloses an energy storage device equipped with the aforementioned battery cells.

[0020] The above technical solution has the following advantages: This application features raised and recessed ribs on the same sidewall of the casing, with the ribs staggered. This creates a natural venting channel between the electrode assembly and the raised ribs when the electrode assembly is installed inside the casing. Gas, constrained by the venting mechanism, flows rapidly along the hollow venting channel to the end of the casing, serving as an auxiliary venting route for the battery cell. With only minor modifications to the casing, this application not only ensures that the recessed ribs can firmly press and fix the sidewall of the electrode assembly, but also reduces the resistance to gas flow within the battery cell by the venting channel formed between the raised ribs and the electrode assembly. Furthermore, it improves the gas depressurization efficiency within the battery cell, preventing untimely gas release and thus avoiding the electrode assembly from shifting due to stagnant airflow.

[0021] This application also includes a protective groove between the metal plate and the protective section to accommodate the protective plate. The melting point of the protective plate is higher than that of the protective section. In the event of thermal runaway of the battery cell, the protective section reaches its melting temperature and softens and deforms, losing its original structural rigidity. The electrode assembly ends are blocked by the high-melting-point protective plate, while the upper surface of the protective plate abuts against the metal plate, preventing the electrode assembly from moving further upward and blocking the explosion-proof valve. On the one hand, the protective plate prevents the electrode assembly from shifting and adhering to the explosion-proof valve; on the other hand, the through-holes on the protective plate maintain geometric stability at high temperatures, ensuring that high-temperature, high-pressure gas can pass through the through-holes and impact the explosion-proof valve, maintaining a constant cross-section of the flow channel and improving the venting efficiency of the battery cell under thermal runaway conditions. Attached Figure Description

[0022] The present application will now be described in detail with reference to specific embodiments and accompanying drawings, wherein: Figure 1 This is a structural diagram of the battery cell casing of this application; Figure 2 This is a side view of the battery cell casing of this application; Figure 3 This is a partial structural diagram of the battery cell casing of this application; Figure 4 This is a structural diagram of the casing and cover plate assembled into a battery cell according to this application; Figure 5 This is a cross-sectional structural diagram of the battery cell in this application; Figure 6 This is an exploded view of a battery cell from existing technology. Figure 7 This is an exploded view of the battery cell structure in this application; Figure 8 This is a structural diagram of the first cover plate of this application; Figure 9 This is a cross-sectional structural diagram of the first cover plate of this application; Figure 10 This is a partially enlarged structural view of the insulating board of this application; Figure 11 This is an exploded structural diagram of the first cover plate of this application; Figure 12 This is an assembly structure diagram of the insulating board and protective board of this application; Figure 13 This is a top-view structural diagram of the first cover plate of this application; Figure 14 This is a structural diagram of the protective plate of this application; Figure 15 These are three views of the protective plate of this application.

[0023] In the diagram: 10, electrode assembly; 20, first cover plate; 21, insulating plate; 211, protective part; 212, limiting member; 213, protective groove; 214, flow hole; 215, flow groove; 216, limiting part; 22, metal plate; 23, explosion-proof valve; 24, raised edge; 25, concave edge; 26, support part; 261, recessed groove; 262, support frame; 263, through hole; 264, raised rib; 265, air inlet; 266, air passage; 27, connecting plate; 30, insulating film; 40, shell; 41, raised strip; 42, concave strip; 43, exhaust passage; 44, storage cavity; 50, second cover plate; 60, electrode terminal; 70, protective plate; 71, boss; 72, recessed platform; 73, base plate; 74, through hole; 75, corner platform. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the following specific embodiments are merely illustrative of this application and do not constitute a limitation thereof.

[0025] Existing high-capacity energy storage cells typically place the positive and negative terminals on the same side cover plate, and place the explosion-proof valve 23 on the opposite side cover plate, relying on an internally molded plastic structure for insulation and isolation, such as... Figure 6As shown, an insulating film 30 and a housing 40 are sequentially fitted around the outside of the electrode assembly 10. A first cover plate 20 and a second cover plate 50 are respectively installed on the open sides at both ends of the housing 40. The first cover plate 20 is used to install an explosion-proof valve 23, and the second cover plate 50 is used to install positive and negative electrode terminals 60. However, when the existing battery cell experiences thermal runaway, high-temperature and high-pressure gas will be generated in a short time, such as when the temperature is between 150°C and 250°C and the pressure is between 0.5MPa and 2MPa. After the explosion-proof valve 23 opens to release pressure and exhaust gas, the internal pressure of the battery cell on the side where the explosion-proof valve 23 is located will drop instantly. If the gas inside the battery cell is not discharged in time, under the impact of the high-temperature and high-pressure gas flow inside the battery cell, the electrode assembly 10 will move axially towards the explosion-proof valve 23, causing the electrode assembly 10 to block the explosion-proof valve 23 and reduce the effective cross-sectional area of ​​the explosion-proof valve 23 for exhaust. At the same time, the cross-sectional area of ​​the conventional internal flow channel of the battery cell is small and cannot meet the requirements for rapid depressurization of high-temperature and high-pressure gas.

[0026] Please see Figures 1 to 5 , Figures 7 to 15 Based on the analysis of the prior art, this embodiment provides a battery cell casing, a battery cell cover plate, and an energy storage device; in the following embodiments, the first direction, the second direction, and the third direction are perpendicular to each other, and the first direction is the length direction of the casing 40, which can also be called the height direction of the casing 40, the second direction is the width direction of the battery cell cover plate, and the third direction is the width direction of the casing 40, which can also be called the length direction of the battery cell cover plate.

[0027] like Figures 1 to 5 As shown, this embodiment discloses a battery cell housing, including a housing 40, at least one protruding strip 41 and at least one concave strip 42. The interior of the housing 40 has a storage cavity 44 for accommodating an electrode assembly 10. At least one protruding strip 41 and at least one concave strip 42 are alternately arranged on the same side wall of the housing 40 and extend along a first direction of the housing 40. The first direction is the length direction of the housing 40. When the electrode assembly 10 is assembled into the storage cavity 44, the concave strip 42 abuts against the electrode assembly 10 inward. An exhaust channel 43 is defined between the electrode assembly 10 and the protruding strip 41. The exhaust channel 43 connects the two ends of the housing 40 along the first direction.

[0028] In one embodiment of this invention, the housing 40 serves as a basic support for housing the internal components of the battery cell, and it surrounds the electrode assembly 10. The housing 40 can be made of conventional metal materials, such as aluminum of type Al3003-H14 / H18. The housing 40 provides basic protection and sealing for the electrode assembly 10. This embodiment can be adapted to different types of battery cells. For small-capacity cylindrical battery cells, only one end of the housing 40 is open, making it easy to place the electrode assembly 10 directly into the storage cavity 44 of the housing 40. For large-capacity square battery cells, both ends of the housing 40 are open, and both open sides of the housing 40 are used to assemble the battery cell cover. The latter will be used as an example in subsequent embodiments of this application.

[0029] The recessed strip 42 is integrally formed or stamped onto the side wall along the length of the housing 40, and is used to protrude into the interior of the storage cavity 44. The recessed strip 42 is preferably straight along the length of the housing 40 to reduce the gas flow resistance within the housing 40. Alternatively, the recessed strip 42 can be wavy or zigzag-shaped to increase the gas capacity of the exhaust channel 43. The number of recessed strips 42 is not specifically limited, as long as each recessed strip 42 is continuous in the first direction and interspersed with the protruding strip 41. The first direction in this application is the length direction of the housing 40. In the assembled state of the electrode assembly 10, the inner surface of the recessed strip 42 forms a rigid abutment with the outer wall of the electrode assembly 10, thereby limiting and constraining the lateral expansion of the electrode assembly 10 and providing guiding support for the electrode assembly 10 during assembly.

[0030] The layout of the protruding strip 41 is similar to that of the concave strip 42. It is also integrally formed or stamped on the side wall of the housing 40 along the length direction of the housing 40. Of course, in this embodiment, it is preferred to stamp the interlaced concave strips 42, so that the protruding strip 41 can be formed naturally, and the interlaced arrangement between the protruding strip 41 and the concave strip 42 is maintained. This processing method is relatively simple and does not require processing of the protruding strip 41. In this embodiment, the protruding strip 41 is designed to follow the structure of the concave strip 42. For example, if the concave strip 42 is wavy or zigzag, the protruding strip 41 is also designed to be wavy or zigzag. The number of protruding strips 41 is also set according to the number of concave strips 42. It is only necessary to ensure that each protruding strip 41 extends continuously to both ends of the housing 40 along the first direction.

[0031] In this embodiment, after the concave strip 42 abuts against the side wall of the electrode group 10, there is a gap between the convex strip 41 and the outer wall of the electrode group 10. This gap defines the exhaust channel 43 in this embodiment. The exhaust channel 43 connects the two ends of the housing 40 along the first direction. Therefore, the exhaust channel 43 in this embodiment is defined by the convex strip 41 and the electrode group 10 assembled in the housing 40, and the number of exhaust channels 43 corresponds to the number of convex strips 41. When airflow is generated inside the cell, the exhaust channel 43, which runs through the length of the housing 40, allows fluid to be transported from one end of the cell to the other along the channel, preventing the airflow inside the housing 40 from stagnating and accumulating in the middle of the electrode group 10.

[0032] After the electrode assembly 10 is installed into the storage cavity 44 of the housing 40, the inner wall of the concave strip 42 is in close contact with the outer surface of the electrode assembly 10, serving to fix and conduct heat. At the same time, a hollow exhaust channel 43 is naturally formed between the outer surface of the electrode assembly 10 and the inner wall of the convex strip 41. When thermal runaway occurs inside the cell and a large amount of gas is generated, the gas flows rapidly to the end of the housing 40 along the hollow exhaust channel 43 due to the confining effect. In this embodiment, the flow guiding space is defined only by the deformation of the housing 40 itself. With a small modification to the housing 40, not only is it ensured that the concave strip 42 can press and fix the side wall of the electrode assembly 10, but the gas depressurization efficiency inside the cell is also improved, avoiding the electrode assembly 10 from being pushed by the stagnant airflow due to untimely gas discharge.

[0033] As an optional implementation, the cross-section of the housing 40 can be rectangular, polygonal, or waist-shaped, preferably rectangular. The number of the protruding strips 41 and concave strips 42 can be set to one or more parallel arrays according to the width of the sidewall of the housing 40. The extension trajectory of the protruding strips 41 and concave strips 42 can be a continuous straight line or a wave, or multiple collinear discontinuous line segments, as long as the exhaust channel 43 defined between each protruding strip 41 and the electrode group 10 can connect the two ends of the housing 40.

[0034] like Figures 1 to 3 As shown, the housing 40 is a square housing 40, which includes two opposing first sidewalls and two opposing second sidewalls; the outer surface width of the first sidewall is A0, and the outer surface width of the second sidewall is B0, where A0 is less than B0; the wall thickness of the housing 40 is T1; the vertical depth of the recessed strip 42 in the storage cavity 44 is H, and the lateral width of the recessed strip 42 along the outer surface of the first sidewall is W1; the dimensional parameters of the housing 40 satisfy the following relationship: ; .

[0035] In a specific example, the outer surface width A0 of the first sidewall is the dimension of the housing 40 along the second direction, that is, the width of the housing 40 on the first sidewall; the outer surface width B0 of the second sidewall is the dimension of the housing 40 along the third direction, that is, the length of the housing 40 used to install the cell cover plate; the outer surface length L0 of the second sidewall is the dimension of the housing 40 along the first direction, that is, the height of the housing 40.

[0036] This embodiment uses two protruding strips 41 and one concave strip 42 as an example, such as... Figures 1 to 3 As shown, by defining the width of the outer surface of the housing 40 on the first sidewall as A0 and the transverse width of the recess 42 along the outer surface of the first sidewall as W1, this embodiment ensures the venting effect of the battery cell by making the above relationship fall into the specified condition. Within the specified range, the battery cell must provide sufficient support force to the internal electrode assembly 10, while also ensuring adequate exhaust channels 43 so that high-temperature, high-pressure gas can be quickly guided from the exhaust channels 43 to the explosion-proof valve 23 on the end of the battery cell cover. If the above relationship is less than 0.55, it means that the value of W1 is too large, which will result in the total width of the exhaust channel 43 being too narrow. When thermal runaway occurs inside the battery cell, the exhaust resistance will increase due to the insufficient cross-sectional area of ​​the exhaust channel 43, and the airflow will not be able to be discharged in time, which may easily cause the casing 40 to tear and explode. If the above relationship is greater than 0.65, it means that the value of W1 is too small, which will result in the total width of the exhaust channel 43 being too wide. The effective contact area of ​​the concave strip 42 against the electrode assembly 10 will be greatly reduced, which will not only reduce the fixing effect on the electrode assembly 10, making the electrode assembly 10 prone to shaking, but also reduce the efficiency of the electrode assembly 10 in conducting heat to the casing 40, affecting the heat dissipation performance during normal use.

[0037] Furthermore, this embodiment also defines the relationship between the vertical depths of the recessed strip 42 into the storage cavity 44 as H, A0, B0, and W1, so that the values ​​of the above relationship are within the range of The range of values ​​ensures the venting effect of the battery cell, balancing the volumetric energy density of the battery cell with the venting safety requirements during thermal runaway, thus achieving an optimal balance in the space allocation of the venting channel 43. If the above relationship is lower than 1.2, the absolute volume of the venting channel 43 will be too small, causing blockage and a venting rate far lower than the gas production rate. Even if the explosion-proof valve 23 is opened, it will not effectively relieve pressure. If the above relationship is higher than 2.3, the venting channel 43 will occupy too much internal space of the battery cell, significantly compressing the volume of the electrode assembly 10, resulting in a decrease in the battery cell's capacity and volumetric energy density. Simultaneously, an excessively large vertical depth H will increase the processing difficulty of the housing 40, and the structure of the housing 40 will gradually weaken. Therefore, in this embodiment, it is preferable to... The value of is limited to The range.

[0038] This embodiment limits the dimensions of the housing 40, the concave strip 42, and the convex strip 41 to the aforementioned ratio range. This ensures that the contact area provided by the concave strip 42 prevents the electrode assembly 10 from shaking violently, and that the exhaust channel 43 reserved by the convex strip 41 and the electrode assembly 10 meets the exhaust rate requirements. Therefore, compared to existing solutions, this further eliminates the risk of stress concentration in the housing 40 due to excessive exhaust resistance, and improves the structural integrity and exhaust yield of the housing 40 under extreme operating conditions.

[0039] like Figures 1 to 3 As shown, as another equivalent alternative size range based on different processes, the above parameter relationship can also be configured as follows: .

[0040] This embodiment addresses the housing 40 produced by a single hot extrusion process. It can be manufactured according to the requirements of the aforementioned relationship, ensuring that the exhaust channel 43 has sufficient cross-sectional area during thermal runaway of the battery cell. It also allows high-temperature, high-pressure airflow to rapidly flow to both ends of the housing 40 without excessively sacrificing the effective space inside the battery cell used to accommodate the electrode assembly 10. This guarantees the high energy density of the energy storage cell and improves the structural stability of the hot-extruded housing 40. If the above relationship is lower than... ,mean The increased value of the value results in a smaller cross-sectional area of ​​the exhaust channel 43 relative to the overall volume of the battery cell. Due to the large capacity of the energy storage cell, the amount and rate of gas generation during thermal runaway are greater. When faced with a sudden burst of high-pressure gas flow, the exhaust channel 43 cannot effectively guide the gas flow to the explosion-proof valve 23 at the end of the casing 40, leading to a serious safety problem of delayed exhaust from the battery cell and subsequent rupture of the casing 40. If the above relationship is higher than... ,mean The decrease in the value leads to an excessively large cross-sectional area of ​​the exhaust channel 43, which easily encroaches on the storage space of the electrode assembly 10, resulting in a decrease in the amount of active material loaded in the battery cell. In the integrated hot extrusion process, the shell 40 is prone to a decrease in its resistance to deformation during charge-discharge expansion cycles, an increase in local stress concentration, and a reduction in the overall mechanical strength of the shell 40.

[0041] Furthermore, this embodiment can be applied to large-capacity energy storage cells. The outer surface width A0 of the housing 40 on the first side wall can be selected as 50-75mm, the outer surface width B0 of the housing 40 on the second side wall can be selected as 150-200mm, and the length L0 of the housing 40 can be selected as 400-600mm.

[0042] like Figure 3 and Figure 5As shown, as an optional implementation, in order to further balance the space utilization rate inside the battery cell and the exhaust efficiency under thermal runaway conditions, this embodiment defines the proportional relationship between the total cross-sectional area S5 of the exhaust channels 43 and the cross-sectional area S6 of the electrode assembly 10. Specifically, after the electrode assembly 10 is assembled into the housing 40, the total cross-sectional area of ​​the exhaust channels 43 defined between the inner side of the protrusion 41 of the first sidewall and the outer surface of the electrode assembly 10 is denoted as S5, and the cross-sectional area of ​​the electrode assembly 10 itself is denoted as S6. The two satisfy the following mathematical relationship: .

[0043] This embodiment, by controlling the above ratio within the range of 0.2 to 0.25, ensures that the large-capacity energy storage cell maintains a high volumetric energy density while possessing a more reliable safe pressure relief capability. If the ratio in the above formula is less than 0.2, it means that the cross-sectional area S5 of the exhaust channel 43 is too small relative to the volume of the electrode group 10. When the cell experiences thermal runaway and instantly generates a large amount of high-pressure mixed gas, the excessively narrow exhaust channel 43 will cause a sudden increase in the gas discharge back pressure; fluid resistance will prevent the airflow from being guided to the explosion-proof valve 23 in time, which may easily cause irreversible bulging or tearing of the sidewall of the casing 40. Conversely, if the ratio of the above formula is higher than 0.25, it indicates that the exhaust channel 43 occupies too much space inside the housing 40. This not only reduces the volume of the cell used to fill the active material and lowers the energy density, but also weakens the surface contact pressing force of the recessed strip 42 on the side wall of the electrode assembly 10. As a result, the electrode assembly 10 is more prone to irregular shaking and swaying when subjected to internal airflow impact or external vibration. In addition, an increase in the cross-sectional area of ​​the exhaust channel 43 will also show a trend of diminishing marginal effects, resulting in spatial redundancy of the exhaust channel 43. Therefore, the cross-sectional area ratio range defined in this embodiment achieves an optimal balance between the space of the housing 40 pressing the electrode assembly 10 and the exhaust channel 43.

[0044] like Figures 1 to 3 As shown, the inner walls on both sides of the concave strip 42 are inclined relative to the reference plane of the first side wall and form a taper N1, wherein, The transition between the concave strip 42 and the convex strip 41 is provided with a rounded corner of radius R1, wherein... .

[0045] In one embodiment of this application, the reference plane of the first sidewall is the horizontal plane on which the plate surface of the protrusion 41 is located, such as... Figure 3 As shown, to improve the production yield of the housing 40, this embodiment sets a taper N1 at both ends of the concave strip 42, and the transition between the concave strip 42 and the convex strip 41 is set as a rounded corner with a radius of R1. The taper and rounded corner not only facilitate die extrusion molding or roll forming, but also reduce the flow resistance of gas in the exhaust channel 43. If the taper N1 in this embodiment is lower than... If the draft angle is too small during the production of the housing 40, the housing 40 is prone to sticking to the mold during hot extrusion molding, making demolding difficult. If a roll forming process is used, excessive stress concentration is likely to occur at the root of the bend. If the fillet radius R1 is less than 0.2mm, the transition angle will be too sharp, and the housing 40 will tear at the bend during production, resulting in a decrease in the production yield of the housing 40. It will also tear under the force of the expansion of the electrode assembly 10. If the taper of this embodiment is higher than This will reduce the flat area at the bottom of the concave strip 42, decreasing the stable contact effect with the electrode assembly 10, and will also occupy the effective width of the exhaust channel 43; if the radius R1 of the rounded corner is greater than When this happens, the edge of the exhaust channel 43 will become flat, which not only reduces the effective cross-sectional area of ​​the exhaust channel 43, but also leads to inaccurate positioning of the pole group 10 during assembly.

[0046] This embodiment defines the fillet and taper N1 of the concave strip 42 and the convex strip 41 in the transition area, and defines the specific range of the taper N1 and the fillet. This allows the stress to be smoothly distributed to both ends of the shell 40 along the taper N1 and the fillet R1 when the shell 40 is subjected to the stress of the outward expansion of the internal high-pressure gas. This further eliminates the stress concentration cracking defect at the right angle transition and improves the compressive and tensile strength of the shell 40.

[0047] like Figures 1 to 3 As shown, the housing 40 has a weld seam that penetrates its wall thickness and extends along the first direction; the width of the weld seam is a, and satisfies: .

[0048] In one embodiment of this application, the embodiment defines a weld seam. and the wall thickness of the shell 40 The relation, if the above relation is in Within this range, uniform stress on the extrusion die can be ensured, while also improving the production yield of the shell 40; furthermore, it can meet the welding requirements of the weld, avoid false welds caused by excessively narrow welds, and improve the tear resistance of the weld itself. If the above relationship is lower than... This indicates the weld seam If the width is too small, there may be a risk of incomplete penetration or poor soldering. Under the high voltage inside the cell, the weld is very prone to cracking. If the above relationship exceeds... Then the weld If the width is too large, and the welding power or speed is too high or too low during hot extrusion, the weld seam will... The weld is significantly affected by welding heat. The intensity will decrease.

[0049] Therefore, in order to balance the production yield rate and the exhaust volume requirements of the casing 40, this embodiment will [determine the weld seam]. The ratio of the width to the shell wall thickness T1 of 40 is limited to... The range ensures the tear resistance of the weld itself, while also taking into account the production and yield requirements of the shell 40.

[0050] like Figures 1 to 3 As shown, the housing 40 is an integrally thermoformed part, and satisfies the following: ; Alternatively, the housing 40 is a roll-formed, bent, and welded part, and satisfies the following: .

[0051] In one embodiment of this application, as Figure 3 As shown, The vertical depth of the recess 42 into the storage cavity 44. The wall thickness of the shell 40 is defined in this embodiment. and The ratio at Within this range, the uniformity of stress on the mold is ensured, while also improving the production yield of the shell 40. If the above ratio is lower than... This indicates the wall thickness of shell 40. If the wall thickness is too high, the depth of the venting channel 43 will be insufficient, failing to meet the high venting capacity requirements of large energy storage cells; if the above ratio is higher than 3.5, it indicates that the wall thickness is too high. If the thickness is too thin, it will reduce the safety performance of the battery cell and also cause uneven wall thickness of the extruded shell, reducing the yield rate.

[0052] Furthermore, this embodiment also defines the outer surface width of the first sidewall as A0 and the wall thickness as... The ratio relationship is defined, and its range is set. This ensures a high yield rate in the welding production of the shell 40, guaranteeing the dimensional stability and fit of the shell 40 during weld assembly. If the above relationship is lower than... This indicates the wall thickness of the shell 40. If the wall thickness is too high, the depth of the exhaust channel 43 will be insufficient, failing to meet the high exhaust volume requirements of large energy storage cells; if the above relationship is higher than 10.0, it indicates that the wall thickness is too high. If the thickness is too thin, it will reduce the safety performance of the battery cell and also cause uneven wall thickness of the extruded shell, reducing the yield rate.

[0053] Therefore, when the shell 40 in this embodiment is produced by roll bending and welding, its wall thickness is... Optional .

[0054] This application also discloses the material of the shell 40, which may be a high-strength AL3003 alloy, with the following chemical composition by mass percentage: Si: 0.15% 0.20%, Mn: 1.1% 1.2%, Fe<0.5%, Cu<0.2%, Ti<0.03%, Mg<0.005%, Zn<0.01%, Cr<0.005%, and Zr<0.1%.

[0055] In one embodiment of this application, Si is typically considered a harmful element in conventional aluminum-manganese alloy systems; in this embodiment, the shell 40 is preferably made of a high-strength aluminum-manganese alloy, and the Si (silicon) content parameter is limited to 0.15%. Within a range of 0.20%, the metallographic structure can be effectively refined, thereby avoiding stamping cracks. In addition, this embodiment also combines with Mn (manganese) element to ensure that the alloy has excellent comprehensive mechanical properties, and significantly improves the plasticity and crack resistance of the shell 40 during processing.

[0056] Specifically, if the Si (silicon) content in this embodiment is below 0.15%, the Si content is negligible and insufficient to fully exert its effect of refining the metallographic structure. The internal structure of the aluminum material is not optimized, making it difficult to provide the required crack resistance during deep stamping, extrusion molding, or roll bending, thus failing to effectively improve production yield. If the Si (silicon) content in this embodiment exceeds 0.20%, since Si itself is a harmful impurity in aluminum-manganese alloys, a high content will damage the original ductility of the aluminum material, leading to a reduction in its plasticity. In the process of stamping or edge bending of the shell, brittle fracture is very likely to occur at stress concentration points.

[0057] Furthermore, the Mn (manganese) content parameter specified in this embodiment is 1.1%. 1.2% Mn (manganese) is the main alloying element in Al3003 alloy. Its addition amount needs to be matched with that of Si to balance the strength and toughness of the material. Mn can effectively refine the aluminum grains, improve the overall structural strength of the material, and maximize the comprehensive mechanical properties of the aluminum. It provides high strength while maintaining high plasticity, thus improving the overall crack resistance of the product.

[0058] If the Mn (manganese) content is below 1.1%, the low manganese content will result in insufficient grain refinement of the aluminum material, leading to insufficient tensile strength and yield strength of the shell 40. Faced with the high-temperature, high-pressure gas flow impact generated during thermal runaway of a large-capacity energy storage cell, the weaker shell 40 is prone to expansion deformation or even direct rupture. If the Mn (manganese) content exceeds the upper limit of 1.2%, while the excessive manganese content can increase hardness, it will lead to the formation of excessive intermetallic compounds within the alloy, resulting in a significant reduction in plasticity. This prevents the aluminum material from undergoing smooth plastic flow when subjected to the severe deformation forces of the stamping die, also leading to stamping cracks.

[0059] In addition, the remaining elements are the range that the shell 40 is normally selected from, and will not be described again here.

[0060] like Figures 8 to 12 As shown, a battery cell cover includes a metal plate 22, an explosion-proof valve 23, an insulating plate 21, and a protective part 211. The metal plate 22 has at least one convex edge 24 and at least one concave edge 25 staggered at both ends along a third direction, the convex edges 24 and the concave edges 25 being used for mounting to the ends of the battery cell casing. The explosion-proof valve 23 is disposed on the metal plate 22. The insulating plate 21 is connected to one side of the metal plate 22. The protective part 211 is connected to the insulating plate 21 and is disposed directly opposite to the explosion-proof valve 23, the protective part 211 facing the metal plate 22. One side is recessed and together with the metal plate 22, defines a protective groove 213. The protective part 211 has a flow hole 214 that communicates with the protective groove 213. The protective plate 70 is disposed in the protective groove 213, and the side facing the explosion-proof valve 23 abuts against the metal plate 22. The protective plate 70 has a through hole 74, so that the airflow flows through the through hole 214 and the through hole 74 to the explosion-proof valve 23. The melting point of the protective plate 70 is higher than the melting point of the protective part 211. The third direction is the length direction of the metal plate 22.

[0061] The metal plate 22 is the basic sealing structure constituting the cell cover. It is usually made of conventional aluminum alloy or stainless steel, such as Al3003-H14 / H18, with an Al content ≥98%. The explosion-proof valve 23 is embedded or welded to the pre-set opening of the metal plate 22 as a designated weak point. The metal plate 22 and the explosion-proof valve 23 together maintain the sealed environment inside the cell. When the fluid pressure inside the cell reaches the fatigue yield threshold of the explosion-proof valve 23, the groove of the explosion-proof valve 23 breaks and opens, forming a pressure relief channel to the external environment, thus constituting a safe pressure relief channel for the cell.

[0062] In addition, at least one convex edge 24 and at least one concave edge 25 are provided at both ends of the metal plate 22 in an alternating manner. The convex edge 24 and the concave edge 25 are preferably integrally formed at both ends of the metal plate 22, and the distribution of the convex edge 24 and the concave edge 25 corresponds to the convex strip 41 and the concave strip 42 at the end of the housing 40. During final assembly, the convex edge 24 and the concave edge 25 are used to form a nested closure with the housing 40 and establish a sealed boundary with the external environment.

[0063] like Figures 9 to 11 As shown, the insulating plate 21 is attached to the side of the metal plate 22 facing the inside of the battery cell. The insulating plate 21 can be injection molded from conventional insulating plastic materials such as polypropylene (PP) and polybutylene terephthalate (PBT). The protective part 211, as part of the insulating plate 21, covers the area of ​​the explosion-proof valve 23 in space as its projection onto the metal plate 22. The side of the protective part 211 facing the metal plate 22 is partially concave, thereby defining a specific protective groove 213 together with the metal plate 22. The protective groove 213 can accommodate the entire protective plate 70. Several flow holes 214 are provided on the wall of the protective part 211 to facilitate the flow of fluid in the battery cell into the protective groove 213 through the flow holes 214. The protective part 211 can be integrally formed on the insulating plate 21 or separately formed and assembled on the insulating plate 21. The choice can be made according to the stamping or assembly process.

[0064] like Figure 7 , Figures 9 to 11 As shown, under normal operating conditions of the battery cell, the insulating plate 21 is used to isolate the internal electrode group 10 from the metal plate 22, and also supports the end of the electrode group 10. When the battery cell generates high temperature and high pressure gas due to thermal runaway, the flow hole 214 serves as a primary fluid guiding channel to gather the dispersed airflow into the protective groove 213. In this embodiment, the recessed structure of the protective part 211 provides vertical assembly allowance, and the assembled protective plate 70 can further reduce the possibility of battery cell danger through the jet ejected from the battery cell.

[0065] like Figure 10 and Figure 11As shown, the protective plate 70 is embedded in the aforementioned protective groove 213. Its upper surface directly abuts against the metal plate 22, and its lower surface is supported by the protective part 211, so that the upper and lower sides of the protective plate 70 are tightly attached to the metal plate 22 and the protective part 211, respectively. At least two sides of the protective plate 70 are also attached to or connected to the inner wall of the protective groove 213 to prevent the protective plate 70 from moving within the protective groove 213. The protective plate 70 has several through holes 74, allowing the fluid in the protective groove 213 to flow through the through holes 74 to the explosion-proof valve 23, so that high-temperature and high-pressure gas can be ejected from the explosion-proof valve 23. In this embodiment, the protective plate 70 is made of a high-temperature resistant material with a melting point significantly higher than that of the plastic material of the insulating plate 21, ensuring that the protective plate 70 can meet the protection requirements of high-temperature and high-pressure gas.

[0066] In the event of thermal runaway of the battery cell, the airflow generated by the battery cell flows through the exhaust channel 43 on the side wall of the casing 40 to the battery cell cover plate, and gradually converges at both ends of the battery cell cover plate in a third direction to the protective part 211 of the battery cell cover plate. The airflow first passes through the flow hole 214 on the protective part 211 and enters the protective groove 213. As the internal temperature of the battery cell rises sharply, the plastic material of the protective part 211 softens and deforms due to reaching the melting temperature, and it loses its original structural rigidity. At this time, the electrode assembly 10 moves towards the cover plate under the action of pressure difference. The high melting point protective plate 70 takes over the role of restricting the electrode assembly 10 from the protective part 211. The electrode assembly 10, which is pushed upward by the expansion of the electrode assembly 10 or the airflow, will directly abut against the lower surface of the protective plate 70. Since the upper surface of the protective plate 70 abuts against the metal plate 22, it prevents the electrode assembly 10 from moving further upward and prevents the electrode assembly 10 from blocking the explosion-proof valve 23. In this embodiment, the protective plate 70 blocks the movement of the electrode assembly 10, preventing it from sticking to the explosion-proof valve 23. Furthermore, the through-holes 74 on the protective plate 70 maintain geometric stability even at high temperatures. The cell cover plate in this embodiment utilizes the difference in melting points between the materials of the protective part 211 and the protective plate 70. Simultaneously, the spatial arrangement of the protective plate 70 within the protective groove 213 ensures that high-temperature, high-pressure gas can pass through the through-holes 74 and impact the explosion-proof valve 23, maintaining a constant cross-section of the flow channel and eliminating the safety hazard of the electrode assembly 10 blocking the explosion-proof valve 23 under extreme cell operating conditions.

[0067] As an optional implementation, the protective part 211 and the insulating plate 21 can be integrally injection molded or connected by separate snap-fit. Regarding the material of the protective plate 70, in addition to conventional metal stamping parts, in a specific example, industrial-grade high-temperature resistant ceramic sheets (such as alumina ceramics) or high-strength composite fiberglass boards can also be selected. As long as their melting point is higher than that of the material of the protective part 211, they can effectively achieve the above-mentioned structural support function under high temperature. The contact method between the protective plate 70 and the metal plate 22 can be interference fit, riveting, or bonding with structural adhesive. The flow holes 214 on the protective part 211 and the through holes 74 on the protective plate 70 can be arranged coaxially and directly opposite each other, or they can be staggered to form a labyrinth-type airflow buffer channel.

[0068] like Figure 14 and Figure 15 As shown, the protective plate 70 is made of metal material, and the metal material satisfies the following requirements: tensile strength ≥165MPa, yield strength ≥145MPa.

[0069] As an optional implementation, this embodiment limits the protective plate 70 to a metal part with specific performance indicators. During the instantaneous combustion of the battery cell, the transient gas pressure and thrust of the electrode assembly 10 generated internally can reach several thousand Newtons. If the yield strength of the protective plate 70 material is insufficient, the protective plate 70 will undergo plastic flexural deformation at the stress point, causing the through hole 74 to become elliptical or even close. This embodiment limits the tensile strength of the protective plate 70 to ≥165MPa and the yield strength to ≥145MPa, ensuring that the stress response of the protective plate 70 remains within the elastic deformation range when subjected to the instantaneous high-frequency pulse load of the electrode assembly 10. Compared to existing solutions, further limiting the above stress thresholds can prevent the protective plate 70 from flexing or breaking when impacted by the electrode assembly 10, ensuring that the through hole 74 does not deform, improving the deformation resistance of the protective plate 70 under extreme impact, ensuring the support strength of the protective plate 70, and maintaining the stability of the cross-sectional area of ​​the through hole 74.

[0070] like Figure 12 , Figure 14 and Figure 15 As shown, the protective plate 70 includes a base plate 73 and protrusions 71 and recesses 72 disposed on the edge of the base plate 73 and arranged in an alternating manner; the protrusions 71 abut against the side of the metal plate 22 facing the protective groove 213; the recesses 72 are connected to the side of the protective part 211 facing the metal plate 22.

[0071] As an optional implementation, the protective plate 70 in this embodiment has an undulating stepped edge structure. During assembly, the boss 71, as the high point, forms a surface contact with the metal plate 22, while the recessed platform 72, as the low point, nests with the lower protective part 211. The protective plate 70 adopts a staggered arrangement, allowing the high-temperature, high-pressure gas inside the battery cell to diffuse outwards along the height difference gap between the boss 71 and the recessed platform 72, in addition to passing through the central through-hole 74. This not only prevents the protective plate 70 from slipping out of the protective groove 213 but also adds an auxiliary exhaust bypass within the protective groove 213, reducing local fluid back pressure.

[0072] like Figure 14 As shown, in one optional embodiment, corner pedestals 75 are provided at the corners of the protective plate 70. These can be understood as protrusions 71 at the corners of the protective plate 70. The corner pedestals 75 are primarily designed to ensure that the corners of the protective plate 70 can fully rest against the surface of the metal plate 22, thus ensuring that the substrate 73 and the metal plate 22 are parallel. Under the impact of high-temperature and high-pressure gas, this prevents the protective plate 70 from shifting or experiencing uneven stress due to tilting, thereby affecting its use.

[0073] In this embodiment, a boss 71, a recessed platform 72, and a corner platform 75 are provided in the first direction as support legs. By utilizing the staggered stepped structure of the edge of the protective plate 70, both fixed anti-slip and venting effect are achieved in the extremely small protective groove 213.

[0074] like Figure 10 As shown, furthermore, a limiting member 212 is also provided in the protective groove 213. The limiting member 212 can be a snap-fit ​​integrally formed on the protective part 211. After the protective plate 70 is assembled in the protective groove 213, the limiting member 212 can engage and lock the recessed platform 72, so that the recessed platforms 72 on both sides of the protective plate 70 are firmly locked in the protective groove 213 to prevent the protective plate 70 from moving within the protective groove 213. Alternatively, the limiting member 212 can also be a groove formed on the protective part 211, so that the recessed platform 72 is restricted within the groove, which can also achieve the purpose of restricting the movement of the protective plate 70. This embodiment does not limit the specific form of the limiting member 212, as long as the limiting member 212 can be set in the protective groove 213 and can meet the requirement of locking the protective plate 70.

[0075] like Figures 10 to 12As shown, a limiting part 216 is also provided on the inner wall of the protective groove 213. The limiting part 216 is a groove, protrusion or block integrally formed on the inner wall of the protective groove 213. When the protective plate 70 is assembled in the protective groove 213, the countersunk platform 72 on the edge of the protective plate 70 will be embedded in the limiting part 216. At the same time, it can also cooperate with the locking of the aforementioned limiting member 212 to firmly lock the protective plate 70 in the protective groove 213, so as to prevent the protective plate 70 from moving in the protective groove 213.

[0076] like Figure 14 and Figure 15 As shown, the total length of the protrusion 71 contacting the metal plate 22 is L, and the perimeter of the protective plate 70 is U. Therefore: .

[0077] As an optional implementation, this embodiment defines the ratio of the side length of the boss 71 to the side length of the protective plate 70. The protective plate 70 is typically square, and the total length of the boss 71 contacting the metal plate 22 is L, which includes the length of all bosses 71 and the corner truncated pyramids 75 described in the previous embodiment. The limitation of this embodiment lies in the ratio of the length of the boss 71 to the perimeter of the substrate 73. If the ratio is less than 0.25, the contact area of ​​the boss 71 is too small, making it prone to localized stress concentration under the pushing force of the electrode assembly 10, leading to a depression in the metal plate 22. Simultaneously, the structural strength of the protective plate 70 is insufficient, easily causing deformation and further puncture or depression in the metal plate 22. If the ratio is greater than 0.35, the edge bypass current channel is excessively occupied, increasing the exhaust back pressure of the battery cell. This embodiment effectively balances power transmission stability and lateral exhaust efficiency through a specific range of side length ratios.

[0078] As an alternative implementation, the shape of the protective plate 70 can also be selected from various other forms, such as a circular plate, a prismatic plate, or a trapezoidal plate. Here, it is only necessary to ensure that the protective plate 70 can be perfectly filled in the protective groove 213 and abut against the metal plate 22 and the protective part 211.

[0079] like Figure 14 and Figure 15 As shown, the thickness of the substrate 73 is T0, the height of the recessed platform 72 protruding from the substrate 73 is H1, and the height of the boss 71 protruding from the substrate 73 is H2. Then: ; .

[0080] As an optional implementation, this embodiment typically provides a chamfered radius (R-angle) in the transition area between the boss 71 and the recess 72 to eliminate stress concentration. During the metal stamping process, if the difference between the step height and the thickness of the substrate 73 is too large, it can lead to material stretching and thinning or even micro-tears. Therefore, this embodiment limits the ratio of the boss 71 and the recess 72 to the substrate 73 to the step height, and limits the step height to between 0.8 and 1.3 times the thickness of the substrate 73. This ensures the uniformity of material flow during die stamping, avoids micro-cracks at the roots of the boss 71 and the recess 72, maintains the yield strength at the staggered edges, and effectively prevents shear fracture at the roots of the boss 71 and the recess 72 when subjected to vertical impact from the pole assembly 10, thus ensuring the structural fatigue life of the protective plate 70 under long-term vibration conditions.

[0081] like Figure 12 , Figure 14 and Figure 15 As shown, the substrate 73 is rectangular with a length of A2 and a width of B2. The area of ​​the substrate 73 is... for: ; The effective opening area of ​​the explosion-proof valve 23 is S0, the total projected area of ​​the boss 71 and the countersunk platform 72 on the plane of the substrate 73 is S2, the total area of ​​the through hole 74 is S3, and the cross-sectional area of ​​the flow channel between the protective plate 70 and the metal plate 22 is S4. Therefore:

[0082]

[0083] .

[0084] As an optional implementation, this embodiment defines the specific shape of the substrate 73 as a rectangle, and also defines the corresponding relationships of the explosion-proof valve 23, the boss 71, and the countersunk platform 72 on the rectangle, in order to further increase the flow area of ​​the protective plate 70. Specifically: After thermal runaway occurs in the battery cell, fluid will be ejected from the explosion-proof valve 23. The effective opening area of ​​the explosion-proof valve 23 at this time is denoted as S0. Figure 15 As shown, when viewed from above, the area of ​​the protective plate 70, including the area of ​​the protrusions 71 and the recesses 72 projected onto the substrate 73, is denoted as S2. S2 also includes the area of ​​the corner frustum 75. (The text repeats itself here.) Figure 15 As shown, a plurality of vias 74 are formed in the middle of the substrate 73, and the product of the number of vias 74 and the number of individual vias 74 is the total area, denoted as S3; there is a gap between the protective plate 70 and the metal plate 22, as shown in the figure. Figure 10The area shown by the dashed line is the flow channel between the protective plate 70 and the metal plate 22, denoted as S4.

[0085] like Figure 15 As shown, (Right now The formula defines the proportion of the total projected area of ​​the boss 71 and the recessed area 72 to the total area of ​​the substrate 73. In this embodiment, it is controlled between 4% and 5%. If the proportion is less than 0.4, it will affect the structural strength of the protective plate 70 and may cause collapse and deformation during the thermal runaway of the battery cell. If the proportion is greater than 0.5, the large proportion of the boss 71 and the recessed area 72 will interfere with the welding area of ​​the explosion-proof valve 23. Therefore, the range value selected in this embodiment ensures that the center of the protective plate 70 has sufficient area to bear the impact load of the electrode group 10, while ensuring that the edges are not too wide and interfere with the welding area of ​​the explosion-proof valve 23.

[0086] In a specific cell example, the substrate length is 73. ,width 73 substrate area The total projected area of ​​the edge protrusion 71 and the recessed platform 72 .at this time The results meet the requirements of Formula 1; and through simulation analysis, the internal exhaust resistance of the battery cell is small, the explosion-proof valve 23 opens normally, and there are no problems such as the metal plate 22 cracking due to untimely exhaust. In addition, the protective plate 70 is not deformed, and the electrode group 10 in the battery cell does not have the problem of surging and blocking the explosion-proof valve 23.

[0087] The formula defines the ratio of the total area of ​​the through-holes 74 in the protective plate 70 body to the total area of ​​the substrate 73. If it is less than 0.2, the current resistance in the cell will be too high, leading to a sudden increase in internal back pressure; if it is greater than 0.3, the protective plate 70 body will have a large amount of hollowing out, resulting in a decrease in yield strength. Therefore, the range set in this embodiment ensures the best balance between structural strength and vertical exhaust efficiency.

[0088] As one embodiment, the substrate 73 in the above example is supported. The protective plate 70 has several honeycomb-shaped or waist-shaped through holes 74 in the middle, and the total area of ​​the through holes 74 is... .at this time This meets the interval requirements of Formula 2.

[0089] exist In the formula, S0 represents the total cross-sectional area of ​​high-pressure gas passing through the protective plate 70, while S0 represents the effective opening cross-sectional area of ​​the explosion-proof valve 23. Due to the expansion characteristics of high-temperature gases, if... If the value is greater than S0, a flow blockage will occur at the explosion-proof valve 23; therefore, this embodiment will... Limited to the range of 0.65 to 0.8, the flow channel forms a convergent nozzle effect. The airflow is accelerated after passing through the through-hole 74 of the protective plate 70, impacting the explosion-proof valve 23 with higher dynamic pressure, significantly reducing the valve opening delay; if Below 0.65, such as 0.6, the area of ​​the protective plate 70 is too small, the venting resistance inside the cell is too high, and there is a phenomenon of untimely venting, which can easily lead to tearing of the cell casing 40; if If the value exceeds 0.8, it will cause a blockage in the flow at the explosion-proof valve 23.

[0090] As one embodiment, the effective opening area of ​​the explosion-proof valve 23 in the above example is... Airflow passes through the flow channel between the protective plate 70 and the metal plate 22. The total exhaust cross-sectional area passing through the protective plate 70 is then... ,ratio In accordance with the convergence acceleration range requirement of the formula in this embodiment, this embodiment forces the airflow to accelerate after passing through the protective plate 70, so as to impact the valve plate of the explosion-proof valve 23 with higher dynamic pressure, which significantly reduces the valve opening delay and increases the pressure relief and exhaust rate per unit time.

[0091] like Figure 12 , Figure 14 and Figure 15 As shown, the distance between the boss 71 and the explosion-proof valve 23 in the third direction (length direction) is C, and the distance in the second direction (width direction) is D, satisfying: .

[0092] As an optional implementation, this embodiment takes the length direction of the metal plate 22 as the third direction and the width direction of the metal plate 22 as the second direction. When the pressure inside the battery cell reaches the threshold, the valve plate of the explosion-proof valve 23 will first bulge upwards, and its metal deformation will extend to the periphery. Therefore, this embodiment retains a redundant gap of 1.5mm to 2.5mm, which can avoid the boundary of the boss 71 interfering with the bulging trajectory of the valve plate and ensure that the explosion-proof valve 23 opens accurately according to the preset burst pressure value.

[0093] In a specific example, this embodiment may select , In actual explosion tests, the maximum lateral expansion of the explosion-proof valve 23 disc was 1.2 mm. In this embodiment, a redundant gap of 2.0 mm was selected to ensure that the disc did not break due to interference throughout the entire process.

[0094] like Figures 8 to 13As shown, both ends of the insulating plate 21 are provided with support portions 26; the support portions 26 protrude from the insulating plate 21 and are on the same horizontal plane as the protective portion 211; and / or the support portions 26 are provided with air passages 266, so that airflow flows from the air passages 266 to the through holes 74 opened on the protective plate 70.

[0095] As an optional implementation, in order to improve the support capacity of the insulating plate 21 for the pole group 10, a support portion 26 is provided at both ends of the insulating plate 21, so that the support portion 26 and the protective portion 211 are on the same horizontal plane, so that the support portion 26 and the protective portion 211 can stably support the end of the pole group 10 on the same horizontal plane, avoiding the pole group 10 being subjected to force in a single local area.

[0096] In addition, in this embodiment, an air passage 266 can be reserved on the support part 26. The air passage 266 is preferably located on the periphery of the support part 26, that is, the size of the support part 26 is smaller than the size of the end of the insulating plate 21. The air passage 266 on the periphery of the support part 26 is reserved so that the high temperature and high pressure gas located at the end can flow around the air passage 266 on the periphery of the support part 26 to the flow hole 214.

[0097] like Figure 12 and Figure 13 As shown, to further increase the flow rate of gas to the protective groove 213, a flow channel 215 can be opened at the junction of the protective part 211 and the metal plate 22. The flow channel 215 can serve as a bypass channel, allowing the gas in the gas passage 266 to bypass the flow hole 214 and flow into the protective groove 213 through the flow channel 215, thereby further reducing the exhaust resistance.

[0098] like Figure 8 , Figure 9 , Figures 11 to 13As shown, in one optional embodiment, the support 26 further includes a support frame 262, a recess 261, a through hole 263, a rib 264, an air inlet 265, and the aforementioned air passage 266; wherein, the support frame 262 and the protective part 211 are assembled via a connecting plate 27, preferably the support frame 262, the connecting plate 27, and the protective part 211 are integrally formed, one side of the connecting plate 27 can be fixed to the metal plate 22 by rivets, so that the recess 261 and the protective groove 213 can be connected through the gap between the connecting plate 27 and the metal plate 22; the recess 261 is opened on the side of the support frame 262 facing the metal plate 22, and its similar Similar to the concave structure of the protective part 211 towards the metal plate 22; in order to further improve the support strength of the support frame 262, a vertical rib 264 is provided in the internal space of the sink 261 to improve the stability of the support frame 262. At the same time, the rib 264 also increases the contact area between the metal plate 22 and the support frame 262; when the support frame 262 and the metal plate 22 are closed, the metal plate 22 will block the upper opening of the sink 261, so that the sink 261 is in a closed state; the air inlet 265 is opened on the side wall of the sink 261 away from the protective part 211, and a through hole 263 communicating with the sink 261 is also opened at the bottom of the sink 261.

[0099] In this embodiment, the structure defined above forms a combination of an air inlet 265 and a through hole 263 on the support part 26, which facilitates the communication of gas on the side of the battery cell through the air inlet 265 and the through hole 263. Furthermore, the gas in the sink 261 will also flow through the air passage 266 on the periphery of the support part 26 to the flow hole 214 and flow groove 215 of the protection part 211, further improving the bypass flow path of the gas.

[0100] like Figure 4 , Figure 5 , Figures 7 to 13 As shown, a battery cell includes an electrode assembly 10; an insulating film 30 sleeved on the outer wall of the electrode assembly 10; a housing 40 internally housing the electrode assembly 10 carrying the insulating film 30, the housing 40 employing the aforementioned battery cell housing; a first cover plate 20 and a second cover plate 50 respectively assembled at the open ends of the housing 40, and at least the first cover plate 20 employing the aforementioned battery cell cover plate; wherein, the protruding edge 24 on the first cover plate 20 is mounted on the end of the protruding strip 41, and the concave edge 25 on the first cover plate 20 is mounted on the end of the concave strip 42, such that the first cover plate 20 is sealed to the end of the housing 40, and the exhaust channel 43 is connected to the first cover plate 20.

[0101] As an optional implementation, the first cover plate 20 and the second cover plate 50 are respectively connected to both ends of the housing 40. The protruding edge 24 at the end of the first cover plate 20 matches the cross-sectional shape of the protruding strip 41 at the end of the housing 40, and the concave edge 25 matches the cross-sectional shape of the concave strip 42 at the end of the housing 40. During assembly, the metal edge on the cover plate is inserted into or adheres to the end face of the housing 40 and is cured by laser welding. This connects the exhaust channel 43 provided on the first side wall of the housing 40 to the flow hole 214 through the air passage 266, and then flows to the explosion-proof valve 23 through the flow hole 214, the protective groove 213, and the through hole 74. This increases the airflow branch of the exhaust channel 43 in the explosion-proof valve 23, further improving the exhaust performance of the battery cell.

[0102] After the electrode assembly 10 is wound or stacked and covered with an insulating film 30, it is inserted from one end of the housing 40; in order to prepare a large-capacity energy storage cell, this embodiment uses the above-mentioned cover plate to complete the end encapsulation.

[0103] like Figures 8 to 13 As shown, the first cover plate 20 adopts the cell cover plate of the above embodiment, which has a protective part 211 equipped with a protective plate 70. After the protective part 211 is deformed and melted due to high temperature and high pressure gas, the protective plate 70 can be tightly attached to the electrode group 10, so that there is a certain distance between the electrode group 10 and the explosion-proof valve 23, that is, a flow channel is formed, ensuring that the electrode group 10 will not block the explosion-proof valve 23, so as not to affect the safe exhaust of the cell.

[0104] The second cover plate 50 is used to mount electrode terminals 60 for connecting to the positive and negative electrodes for charging or power extraction. Considering the service life of the energy storage cell, it is typically required to have a long cycle life of 15,000 to 20,000 cycles. To delay the loss of active lithium during cycling, as a preferred embodiment, a specific proportion of lithium replenishing agent (e.g., LNO or LFO material) is mixed into the positive electrode material of the cell electrode assembly 10 in this embodiment.

[0105] In actual process formulation, the amount A of lithium supplementer added (i.e., its mass percentage in the cathode material) is limited to: ; Where H0 is the total height of the protective plate 70, S1 is the outer contour area of ​​the protective plate 70, as shown in the above embodiment; L0 is the length of the battery cell, as shown in the above embodiment. Figure 15 As shown.

[0106] This embodiment provides a specific formula for the mass ratio A of the lithium supplement. If the formula ratio is less than... This means that compared to the axial thrust and gas production brought about by long cells (i.e., L0 large) and high lithium additive content (A large), the volume of the protective plate ( The formula appears too thin, making it highly susceptible to overall shear fracture or thermal perforation under extreme conditions; if the formula ratio is greater than... This indicates that the volume design of the cell electrode assembly 10 is in a state of overperformance. It not only unnecessarily occupies the space for the active material inside the cell, but also excessively prolongs the internal airflow discharge path, increasing the fluid back pressure. This embodiment selects a specific range, which can maximize the utilization of the internal space of the cell while ensuring the ultimate shock resistance performance.

[0107] When the mass percentage A of the lithium replenishing agent reaches the aforementioned range, although the cycle life of the battery cell is significantly improved, due to the oxygen evolution and side reaction characteristics of the material itself, the total amount of high-temperature gas generated and the transient gas generation rate inside the battery cell increase exponentially during the process formation stage, later high-frequency cycling conditions, and when thermal runaway is triggered. To cope with extreme fluid pressure, this application further limits the battery cell housing 40 and the explosion-proof valve 23, specifically as follows: Rated opening pressure of explosion-proof valve 23 Set as: ; Rated burst pressure of casing 40 in free state Set as: ; Furthermore, the two satisfy the linkage equation in the system design: .

[0108] This embodiment requires a shell burst pressure of 40. At least the rated opening pressure of the explosion-proof valve 23 This ensures that, at 1.6 times the density of the lithium replenishment agent, the explosion-proof valve 23 can initiate a yielding and venting action before the casing 40 tears or ruptures, preventing collateral damage caused by the casing 40 exploding in a dense array of energy storage cells. This is especially crucial when the internal pressure of the casing 40 surges due to violent decomposition and gasification. Lower than the rated opening pressure of the explosion-proof valve 23 If the temperature is 1.6 times higher, the casing 40 will tear, but the explosion-proof valve 23 will not be opened, affecting the safety of cell venting.

[0109] like Figure 1 , Figure 7 , Figure 8 and Figure 15 As shown, in order to further adapt to the drastic expansion of electrode assembly 10 and the high-flow-rate venting requirements caused by the high-doping lithium supplement, the relationship between the core components of the cover plate is further defined based on the above-described cover plate embodiment: Let the length of the opening area of ​​the housing 40 (i.e., the mating surface of the first cover plate 20) be B0 and the width be A0. Then the area of ​​the cover plate is... ; The outer contour area of ​​the protective plate is required to be 70. The effective opening area S0 of the explosion-proof valve 23 satisfies: ; Simultaneously, the area of ​​the explosion-proof valve 23 and the total cross-sectional area of ​​the battery cell must meet the following requirements: .

[0110] Because the mechanical upwelling and volume expansion of electrode assembly 10 with lithium supplementation during thermal runaway are far greater than those of conventional electrode assembly 10. The ratio... The value is limited to between 2.0 and 2.5, so that the protective plate 70 forms a protective plate body with an area more than twice that of the explosion-proof valve 23 below the explosion-proof valve 23; this ensures that even if the electrode assembly 10 is irregularly twisted or eccentrically pushed upward, it can still be resisted and limited by the outer edge of the protective plate 70, preventing the soft material released by the electrode assembly 10 from crossing the edge of the protective plate 70 and thus not occupying the space of the explosion-proof valve 23.

[0111] Meanwhile, this embodiment will Limited to between 0.12 and 0.2, the effective opening area S0 of the explosion-proof valve 23 must occupy 12% to 20% of the top cross-section of the battery cell, ensuring that the explosion-proof valve 23 has sufficient flow capacity and avoiding the explosion-proof valve 23 opening being too small, which would cause excessive high-pressure mixed gas to form a blockage flow at the top of the battery cell.

[0112] like Figures 8 to 13 As shown, based on the above embodiment, both ends of the metal plate 22 are provided with staggered convex edges 24 and concave edges 25. Preferably, two convex edges 24 and one concave edge 25 are provided, with one concave edge 25 located between the two convex edges 24. The convex edges 24 at both ends of the metal plate 22 correspond to the convex strips 41 of the housing 40, while the concave edges 25 at both ends of the metal plate 22 correspond to the concave strips 42 of the housing 40. When the first cover plate 20 is installed on the housing 40, the convex edges 24 are embedded and fill the cross section of the convex strips 41, so that the cross section of the convex strips 41 is completely filled; the concave edges 25 are embedded and fill the cross section of the concave strips 42. In this embodiment, through the cooperative arrangement of the convex edges 24, convex strips 41 and concave strips 42, the first cover plate 20 is tightly fitted to the cross section of the convex strips 41 and concave strips 42 at the end of the housing 40, which not only achieves a tight assembly structure, but also connects the exhaust channel 43 with the air passage 266.

[0113] When the battery cell is operating and triggers thermodynamic runaway, the positive electrode material mixed with lithium replenishing agent rapidly releases a large amount of gas. At this time, in addition to the main airflow at the end of the electrode assembly 10 passing through the through hole 74 of the protective plate 70 and being discharged to the explosion-proof valve 23, the expanding gas generated at the edge of the electrode assembly 10 flows through the exhaust channel 43 formed by the protrusion 41 and the electrode assembly 10. The exhaust channel 43 transports the airflow around the electrode assembly 10 upward and smoothly transitions through the air passage 266 around the support part 26. Finally, it flows from the flow hole 214 and the flow groove 215 into the protective groove 213 below the explosion-proof valve 23, and then flows through the protective groove 213 and the through hole 74 to the explosion-proof valve 23.

[0114] The exhaust channel 43 constructed in this application serves as an auxiliary branch; even if expansion occurs at other locations of the electrode group 10, resulting in local air resistance, the electrode group 10 can still ensure high-speed airflow conduction by relying solely on the auxiliary exhaust channel 43, minimizing the pressure stagnation time and further improving the reliability of the cell in long-cycle energy storage devices.

[0115] like Figure 1 , Figure 7 and Figure 8 As shown, this application also discloses an energy storage device equipped with the aforementioned battery cells.

[0116] In this embodiment, the aforementioned cover plate technology is integrated into the battery cell and energy storage device. After the outer wall of the electrode assembly 10 is covered with an insulating film 30, it is installed into the housing 40. The first cover plate 20 and the second cover plate 50 seal the opening of the housing 40. During the array operation of the energy storage device, the improved pressure relief performance of the individual battery cell cover plate prevents the spread of thermal runaway between adjacent cells, thereby improving the system-level fire safety redundancy of the entire energy storage base station.

[0117] Working principle: During normal charging and discharging operation, the electrode group 10 is placed inside the insulating film 30 and closely abuts against the recessed strip 42 of the housing 40, and heat dissipation is transferred through the side wall, so that the overall structure of the cell remains stable.

[0118] When the battery cell experiences extreme overcharging or internal short circuit triggering thermal runaway, the internal temperature of the electrode assembly 10 rises sharply, causing the electrolyte to vaporize and decompose, generating a large amount of high-temperature, high-pressure mixed gas. At this time, the gas is squeezed by the sidewall of the electrode assembly 10 and the concave strip 42, and can only flow along the exhaust channel 43 with the least fluid resistance. The airflow travels along the exhaust channel 43 in the first direction to the end of the housing 40. Since the concave edge 25 and convex edge 24 of the cover plate edge form a closed loop with the concave strip 42 and convex strip 41 of the housing 40, the airflow is guided into the insulating plate 21 area at the bottom of the first cover plate 20, and passes through the flow hole 214 of the protective part 211 and the through hole 74 of the protective plate 70, accumulating in the protective groove 213 inside the explosion-proof valve 23. As the airflow pressure reaches the explosion threshold, the explosion-proof valve 23 opens instantly to release pressure and exhaust gas.

[0119] At the moment of depressurization, the internal pressure of the first cover plate 20 drops sharply, generating a huge axial pressure difference. This drives the massive electrode assembly 10 to move at high speed along the insulating membrane 30 towards the first cover plate 20. The front end of the electrode assembly 10 directly impacts the insulating plate 21 and the protective part 211 of the first cover plate 20. Under the impact of the high-temperature and high-pressure airflow, the plastic protective part 211 may fail due to heat, but the electrode assembly 10 is immediately blocked by the metal protective plate 70, which has a high melting point and high yield strength. The protective plate 70, relying on its surrounding bosses 71 and countersunk platforms 72, transfers the impact stress to the metal plate 22, preventing the electrode assembly 10 from advancing further and blocking the already opened explosion-proof valve 23. The residual airflow inside continues to be discharged to the outside of the battery cell through the through holes 74 on the protective plate 70. At the same time, the exhaust channel 43, as a branch, also continuously guides the airflow around the electrode assembly 10 to the explosion-proof valve 23, completing the airflow discharge of the battery cell.

[0120] The above description is merely a preferred embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the inventive concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A battery cell casing, characterized in that, include: The housing has an internal cavity for accommodating the electrode assembly; At least one convex rib and at least one concave rib are alternately arranged on the same side wall of the housing and extend along a first direction of the housing; The first direction is the length direction of the shell; When the electrode assembly is assembled into the storage cavity, the concave strip abuts against the electrode assembly inward, and an exhaust channel is defined between the electrode assembly and the convex strip. The exhaust channel connects to both ends of the housing along the first direction. The shell is a square shell, which includes two first side walls and two second side walls arranged opposite to each other; The outer surface width of the first sidewall is A0, and the outer surface width of the second sidewall is B0, where A0 is less than B0; The wall thickness of the shell is T1; The vertical depth of the recessed strip into the storage cavity is H, and the lateral width of the recessed strip along the outer surface of the first sidewall is W1. The dimensional parameters of the housing satisfy the following relationship: ； 。 2. The battery cell casing as described in claim 1, characterized in that, The total cross-sectional area of ​​the exhaust passage defined between the first sidewall and the electrode group is S5, and the cross-sectional area of ​​the electrode group is S6. S5 and S6 satisfy the following relationship: 。 3. The battery cell casing as described in claim 1 or 2, characterized in that, The inner walls on both sides of the concave strip are inclined relative to the reference plane of the first side wall, and form a taper N1, wherein, ; The transition between the concave strip and the convex strip is provided with a fillet R1, wherein... .

4. The battery cell casing as described in claim 1, characterized in that, The shell is provided with a weld that penetrates its wall thickness and extends along the first direction; The width of the weld is a, and it satisfies: .

5. The battery cell casing as described in claim 1, characterized in that, The shell is a one-piece hot-extruded molded part, and satisfies the following: ； Alternatively, the housing is a roll-formed, bent, and welded part, and satisfies the following: 。 6. A battery cell cover plate, characterized in that, include: A metal plate has at least one convex edge and at least one concave edge arranged in an alternating manner at both ends along a third direction, the convex edge and the concave edge being used to assemble the end of the battery cell casing; An explosion-proof valve is mounted on the metal plate; An insulating plate is attached to one side of the metal plate; A protective part is connected to the insulating plate and is positioned opposite the explosion-proof valve. The side of the protective part facing the metal plate is recessed and together with the metal plate defines a protective groove. A flow hole communicating with the protective groove is provided on the protective part. A protective plate is disposed within the protective groove, with its side facing the explosion-proof valve abutting against the metal plate; the protective plate has through holes, allowing airflow to pass through the through holes and flow to the explosion-proof valve; the melting point of the protective plate is higher than that of the protective part; Wherein, the third direction is the length direction of the metal plate; The protective plate includes a base plate and protrusions and recesses disposed on the edge of the base plate in an alternating manner; the protrusions abut against the side of the metal plate facing the protective groove; the recesses serve as the lowest point and are connected and nested with the side of the protective part facing the metal plate, so that high-temperature and high-pressure gas can diffuse in all directions along the height difference gap between the protrusions and the recesses.

7. The cell cover plate as described in claim 6, characterized in that, Both ends of the insulating plate are provided with support portions; the support portions protrude from the insulating plate and are on the same horizontal plane as the protective portion; each support portion has a reserved air passage, so that airflow flows from the air passage to the through hole opened on the protective plate.

8. The cell cover plate as described in claim 6, characterized in that, The substrate is rectangular with a length of A2 and a width of B2. The area of ​​the substrate is... for: ； The effective opening area of ​​the explosion-proof valve is S0, the total projected area of ​​the boss and the countersunk platform on the substrate plane is S2, the total area of ​​the through holes is S3, and the cross-sectional area of ​​the flow channel between the protective plate and the metal plate is S4. Therefore: 。 9. A battery cell, characterized in that, include: pole group; An insulating film is fitted onto the outer wall of the electrode assembly; A housing, internally accommodating the electrode assembly carrying the insulating film, wherein the housing adopts the cell housing as described in any one of claims 1 to 5; A first cover plate and a second cover plate are respectively assembled at the two open ends of the housing, and at least the first cover plate is a cell cover plate as described in any one of claims 6 to 8; Wherein, the convex edge on the first cover plate is installed at the end of the convex strip, and the concave edge on the first cover plate is installed at the end of the concave strip, so that the first cover plate is sealed and assembled with the end of the housing, and the exhaust channel is connected to the first cover plate.

10. An energy storage device, characterized in that, It is equipped with the battery cell as described in claim 9.

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