Battery cell top cover, battery cell and energy storage device

Abstract

The application discloses an electric core top cover, an electric core and an energy storage device, and relates to the technical field of energy storage electric cores. Specifically, the electric core top cover comprises a metal plate, an explosion-proof valve, an insulating plate, a protection part, a connecting plate and a flow guide groove. The protection part is protrusively arranged in a direction away from the metal plate and cooperates with the metal plate to define a protection groove. The protection part is provided with a flow hole communicating with the protection groove. The connecting plate is arranged on both sides of the protection part in a first direction and protrudes from the surface of the insulating plate. The flow guide groove is defined by the connecting plate and the metal plate. The flow guide groove is used for connecting two ends of the electric core top cover to the protection groove. The application takes the flow hole as a main flow path and the flow guide groove as an auxiliary flow path. The two flow paths accurately guide the gas in different regions of the electric core to the protection groove. The gas in the dead angle region of the electric core can be quickly discharged to the protection groove. The overall gas flow resistance is reduced, the movement trend of the pole group towards the explosion-proof valve is reduced, and the exhaust efficiency of the electric core is improved.

Description

Technical Field

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

[0002] A battery cell is a medium used to store energy. It has advantages such as high energy density, long cycle life, and low self-discharge rate. It is widely used in electric vehicles, drones, and energy storage power stations to meet the operational requirements of high energy density and long cycle life.

[0003] In existing technologies, battery cell structures generally include a top cover, a shell, an insulating film, electrode groups, and an electrolyte. To achieve thermoelectric separation, high-capacity energy storage cells typically place the positive and negative terminals on the same side of the top cover, while placing the explosion-proof valve on the opposite side. Inside the cell, near the explosion-proof valve, an integrally molded plastic structure is used for insulation and isolation, allowing the explosion-proof valve and electrode groups to be limited by the plastic structure.

[0004] However, the existing technologies mentioned above still have the following shortcomings: When a large-capacity energy storage cell experiences thermal runaway, it produces a large amount of gas at a high rate, generating high-temperature and high-pressure gas in a short period of time. This high-temperature and high-pressure gas flows through the middle of the cell's top cover to the explosion-proof valve, but the gas in the dead zone of the cell cannot be quickly discharged to the explosion-proof valve. In addition, after the explosion-proof valve opens to release pressure, the internal pressure of the cell on the side where the explosion-proof valve is located drops rapidly. Due to the failure of the gas flow inside the cell to be discharged in time, the electrode assembly will move towards the explosion-proof valve. The moving electrode assembly will abut against and block the explosion-proof valve, reducing the effective cross-sectional area of ​​the exhaust channel. This causes a sharp drop in the exhaust effect of the explosion-proof valve, and a large amount of high-temperature and high-pressure gas remains inside the cell and cannot be released quickly, reducing the safety performance of the cell.

[0005] Therefore, this application aims to solve the problem that the gas in the dead corner of the battery cell is difficult to be quickly guided to the explosion-proof valve. At the same time, the gas that is not discharged in time will drive the electrode group to move and block the explosion-proof valve, resulting in low battery cell exhaust efficiency. Summary of the Invention

[0006] The main purpose of this application is to provide a battery cell top cover, a battery cell, and an energy storage device, which aims to solve the problem that the gas in the dead corner inside the battery cell is difficult to guide to the explosion-proof valve quickly, and the gas that is not discharged in time will drive the electrode group to move and block the explosion-proof valve, resulting in low battery cell exhaust efficiency.

[0007] To achieve the above objectives, this application proposes a battery cell top cover, comprising: Metal sheet; An explosion-proof valve is mounted on the metal plate; An insulating plate is attached to one side of the metal plate; The protective part is connected to the insulating plate and is positioned opposite to the explosion-proof valve. The protective part protrudes away from the metal plate and together with the metal plate, defines a protective groove. The protective part has a flow hole that communicates with the protective groove. A connecting plate is disposed on both sides of the protective part along the first direction and protrudes from the surface of the insulating plate. The height at which the connecting plate protrudes from the insulating plate is lower than the protrusion height of the protective part. The flow channel is defined by the connecting plate and the metal plate, and the flow channel is used to connect the two ends of the top cover of the battery cell to the protective channel; The first direction is the length direction of the metal plate.

[0008] Optionally, the connecting plate is provided with at least one flow guide hole, which is used to connect the inner and outer spaces of the flow guide groove.

[0009] Optionally, if the width of the guide channel is W2 and the width of the insulating plate is W1, then: .

[0010] Optionally, it may also include a protective panel; The protective plate is disposed in the protective groove, and its side facing the explosion-proof valve abuts against the metal plate; the protective plate has through holes, so that airflow flows through the through holes and the through holes to the explosion-proof valve; The melting point of the protective plate is higher than that of the protective part.

[0011] 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.

[0012] Optionally, a flow groove is further provided between the protective part and the metal plate; The flow channel is used to connect the inner and outer spaces of the protective channel; The insulating plate is provided with support portions at both ends in the first direction; The support portion protrudes from the insulating plate, and the top surface of the support portion is flush with the top surface of the protective portion; The support portion is provided with an air inlet that connects to the guide groove.

[0013] Optionally, the total area of ​​the guide hole and the flow passage is denoted as S7; the effective opening area of ​​the explosion-proof valve is S0; and the total area of ​​the air inlet and the flow passage is S8. Then: .

[0014] 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 has a storage cavity, the interior of which accommodates the electrode assembly carrying the insulating film; The first cover plate and the second cover plate are respectively assembled at the two open ends of the housing; The first cover plate is the aforementioned battery cell top cover.

[0015] Optionally, the housing has alternating convex and concave ribs on at least one side wall; When the electrode assembly is assembled into the storage cavity, the concave strip abuts against the electrode assembly inward, and the electrode assembly and the convex strip define an exhaust channel, the total cross-sectional area of ​​the exhaust channel being S5; The effective opening area of ​​the explosion-proof valve is S0, and the opening pressure of the explosion-proof valve is... The burst pressure of the shell in its free state is Then we have: .

[0016] This application also discloses an energy storage device equipped with the aforementioned battery cells.

[0017] The above technical solution has the following advantages: This application features a protective groove between the metal plate and the protective section to accommodate the protective plate, with the groove directly facing the explosion-proof valve. The protective section has multiple flow holes, and the connecting plates on both sides of the protective section also have multiple guide grooves. These guide grooves on both sides of the cell top cover direct gas from the sides of the cell to the protective groove, while the flow holes direct gas from the center of the cell to the protective groove. This allows the gas accumulated in the protective groove to overcome the explosion-proof valve and be discharged, thus relieving pressure. Through the combined action of the flow holes and guide grooves, this application achieves a system where the flow holes serve as the main flow path, and the guide grooves as auxiliary flow paths. Together, they accurately guide gas from different areas inside the cell into the protective groove, allowing gas in dead zones to be quickly discharged. This also reduces overall gas flow resistance, decreasing the tendency of the electrode assembly to move towards the explosion-proof valve and improving the cell's venting efficiency.

[0018] In this application, the melting point of the protective plate is higher than that of the protective part. In the event of thermal runaway of the battery cell, the protective part reaches the melting temperature and softens and deforms, losing its original structural rigidity. The ends of the electrode assembly 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 moving and sticking 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 and 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

[0019] The present application will now be described in detail with reference to specific embodiments and accompanying drawings, wherein: Figure 1 This is an exploded view of a battery cell from existing technology. Figure 2 This is an exploded view of the battery cell structure in this application; Figure 3 This is a structural diagram of the first cover plate of this application; Figure 4 This is a cross-sectional structural diagram of the first cover plate of this application; Figure 5 This is a partially enlarged structural view of the insulating board of this application; Figure 6 This is an exploded structural diagram of the first cover plate of this application; Figure 7 This is an assembly structure diagram of the insulating board and metal plate of this application; Figure 8 This is a top-view structural diagram of the first cover plate of this application; Figure 9 This is a structural diagram of the protective plate of this application; Figure 10 These are three views of the protective plate of this application; Figure 11 This is a structural diagram of the battery cell used in this application; Figure 12 This is a cross-sectional structural diagram of the battery cell in this application; Figure 13 This is a structural diagram of the casing of this application.

[0020] In the diagram: 10. Electrode group; 20. First cover plate; 21. Insulating plate; 211. Protective part; 212. Limiting component; 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. Sink; 262. Support frame; 263. Through hole; 264. Raised rib ; 265, Air inlet; 266, Air passage; 27, Connecting plate; 271, Guide hole; 272, Guide groove; 30, Insulating film; 40, Housing; 41, Raised strip; 42, Recessed strip; 43, Exhaust passage; 44, Storage cavity; 50, Second cover plate; 60, Electrode terminal; 70, Protective plate; 71, Boss; 72, Recess; 73, Base plate; 74, Through hole; 75, Corner platform. Detailed Implementation

[0021] 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.

[0022] like Figure 1 As shown, in existing technologies, the battery cell structure generally includes a top cover, a housing 40, an insulating film 30, an electrode assembly 10, and an electrolyte. To achieve thermoelectric separation, high-capacity energy storage cells typically place the positive and negative terminals on the same side of the top cover, and place the explosion-proof valve 23 on the opposite side of the top cover. A plastic structure is used to limit, insulate, and isolate the explosion-proof valve 23 from the electrode assembly 10. The electrode assembly 10 is sequentially fitted with an insulating film 30 and a housing 40, and a first cover plate 20 and a second cover plate 50 are respectively mounted on the open sides of the housing 40. The first cover plate 20 is used to house the explosion-proof valve 23, and the second cover plate 50 is used to house the positive and negative electrode terminals 60. However, when a conventional battery cell experiences thermal runaway, it will generate high-temperature and high-pressure gas in a short time, such as at temperatures between 150°C and 250°C and pressures between 0.5 MPa and 2 MPa.

[0023] When a large-capacity energy storage cell experiences thermal runaway, it generates a large amount of gas at a high rate, producing high-temperature and high-pressure gas in a short period of time. This high-temperature and high-pressure gas flows through the middle of the cell's top cover to the explosion-proof valve 23. However, the gas in the dead zone inside the cell cannot be quickly discharged to the explosion-proof valve 23. Furthermore, after the explosion-proof valve 23 opens to release pressure, the internal pressure of the cell on the side where the explosion-proof valve 23 is located drops rapidly. If the gas flow inside the cell is not discharged in time, the electrode assembly 10 will move towards the explosion-proof valve 23. Since the original plastic structure has been damaged by the impact of the high-temperature and high-pressure gas flow, the moving electrode assembly 10 will abut against and block the explosion-proof valve 23, reducing the effective cross-sectional area of ​​the explosion-proof valve 23. This causes a sharp drop in the venting effect of the explosion-proof valve 23, resulting in a large amount of high-temperature and high-pressure gas remaining inside the cell and unable to be released quickly, thus reducing the safety performance of the cell.

[0024] Please see Figures 2 to 12 Based on the analysis of the prior art, this embodiment provides a battery cell top cover, a battery cell, and an energy storage device.

[0025] like Figures 3 to 8 As shown, this embodiment discloses a battery cell top cover, including a metal plate 22, an explosion-proof valve 23, an insulating plate 21, a protective part 211, a connecting plate 27, and a guide groove 272. 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 opposite to the explosion-proof valve 23. The protective part 211 protrudes away from the metal plate 22 and together with the metal plate 22 defines a protective groove 213. 1. A flow hole 214 is provided on the protective groove 213; a connecting plate 27 is arranged on both sides of the protective part 211 along the first direction and protrudes from the surface of the insulating plate 21. The height of the connecting plate 27 protruding from the insulating plate 21 is lower than the protrusion height of the protective part 211; a guide groove 272 is defined by the connecting plate 27 and the metal plate 22. The guide groove 272 is used to connect the two ends of the top cover of the battery cell to the protective groove 213; the first direction is the length direction of the metal plate 22.

[0026] In one embodiment of this invention, the metal plate 22 forms the basic sealed structure of the battery cell top cover. It is typically 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 a pre-set opening in the metal plate 22, serving as a designated weak point. The metal plate 22 and the explosion-proof valve 23 together maintain the sealed environment inside the battery cell. When the internal fluid pressure of the battery 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 battery cell.

[0027] like Figures 5 to 8 As shown, the insulating plate 21 is attached to the side of the metal plate 22 facing the inside of the cell. The insulating plate 21 can be injection molded from conventional insulating plastic materials such as polypropylene (PP) and polybutylene terephthalate (PBT). The main function of the insulating plate 21 is to separate the electrode group 10 and the metal plate 22, and it also provides support for the electrode group 10.

[0028] like Figures 4 to 8As shown, the protective part 211 is part of the insulating plate 21. Its spatial projection onto the metal plate 22 covers the area of ​​the explosion-proof valve 23. The protective part 211 protrudes in the direction away from the metal plate 22, and the protective part 211 and the metal plate 22 together define a specific protective groove 213, so that the protective groove 213 has sufficient space to accommodate high-temperature and high-pressure gas. Several flow holes 214 are opened on the wall of the protective part 211, so that the fluid in the battery cell can flow into the protective groove 213 through the flow holes 214. The protective part 211 can be integrally formed on the insulating plate 21, so that the protective part 211 is part of the insulating plate 21, or it can be formed separately and assembled on the insulating plate 21. The choice can be made according to the stamping or assembly process.

[0029] like Figure 7 As shown, the connecting plate 27 is disposed at both ends of the protective part 211 in the first direction. The connecting plate 27 is equivalent to the extension of the protective part 211 on both sides in the first direction. The connecting plate 27 is preferably integrally formed with the protective part 211, and the two together constitute a part of the insulating plate 21 in this embodiment. In addition, the connecting plate 27 and the protective part 211 can also be assembled so that the two together form a part of the insulating plate 21 in this embodiment. The connecting plate 27 has a certain thickness and protrudes from the surface of the metal plate 22. The protrusion height of the connecting plate 27 needs to be lower than the height of the protective part 211. This is because the protective part 211 is mainly used to contact the electrode group 10, while the connecting plate 27 is mainly used to connect the protective groove 213 and the end of the cell top cover. The connecting plate 27 also has a guide hole 271 for connecting the following air passage 266. To ensure that the guide hole 271 is not blocked, the protrusion height of the connecting plate 27 must be lower than the height of the protective part 211. The side of the connecting plate 27 facing the metal plate 22 is recessed, so that the connecting plate 27 and the metal plate 22 jointly define the guide groove 272. The guide groove 272 is connected to the protective groove 213, and the end of the guide groove 272 away from the protective groove 213 is connected to the end of the cell top cover.

[0030] When thermal runaway occurs in the battery cell, the gas inside the battery cell can flow to the protective groove 213 through the flow hole 214 on the protective part 211, and can also flow into the protective groove 213 through the end of the top cover of the battery cell and the guide groove 272. This increases the number of branches from the top cover of the battery cell to the protective groove 213, and avoids the dead zone inside the battery cell from being unable to quickly guide the gas to the protective groove 213. Finally, the high temperature and high pressure gas accumulated in the protective groove 213 breaks through the explosion-proof valve 23 to achieve rapid depressurization of the battery cell.

[0031] When the battery cell experiences thermal runaway, resulting in the generation of high-temperature, high-pressure gas inside, the flow-through orifice 214 serves as a primary fluid guiding channel. The dispersed airflow converges through the flow-through orifice 214 and is guided into the protective groove 213, where it is concentrated and breaks through the explosion-proof valve 23 to release pressure. Furthermore, gas in the dead zones of the battery cell enters the guide groove 272 through both ends of the battery cell top cover and is injected into the protective groove 213, thus completing the gas guiding function. This embodiment not only guides the high-temperature, high-pressure gas released from the battery cell through the conventional flow-through orifice 214, but also guides the gas from the dead zones at both ends of the battery cell top cover into the protective groove 213 through the guide groove 272. This improves the gas guiding capacity in multiple angular directions, reduces gas flow resistance, and further reduces the possibility of battery cell hazards. In addition, the airflow inside the battery cell is promptly discharged from the explosion-proof valve 23, preventing gas accumulation from causing the electrode assembly 10 inside the battery cell to move towards the explosion-proof valve 23, thus avoiding obstruction of the explosion-proof valve 23 and affecting the venting effect.

[0032] like Figures 6 to 8 As shown, at least one flow guide hole 271 is provided on the connecting plate 27, and the flow guide hole 271 is used to connect the inner and outer spaces of the flow guide groove 272.

[0033] As one embodiment of this invention, the connecting plate 27 is provided with one or more flow guide holes 271, so that the flow guide holes 271 can connect the inner and outer spaces of the flow guide groove 272. The inner and outer spaces referred to in this invention refer to the internal space and the external space of the flow guide groove 272. Especially after the top cover of the battery cell is assembled, the inner and outer spaces refer to the internal space of the flow guide groove 272 and the space defined between the insulating plate 21 and the electrode group 10 of the battery cell.

[0034] In this embodiment, the number of guide holes 271 is not limited in detail. They are mainly used to connect multiple branches. For example, if the junction of the guide groove 272 and the protective groove 213 is blocked, the gas generated in the dead corner area at both ends of the top cover of the battery cell can flow into the protective groove 213 through the guide groove 272, the guide hole 271, and the flow hole 214, thereby further reducing the resistance to gas emission.

[0035] like Figures 6 to 8 As shown, the width of the guide groove 272 is W2, and the width of the insulating plate 21 is W1, then: .

[0036] As one implementation of this embodiment, this embodiment defines the proportional relationship between the flow guide groove 272 and the insulating plate 21, such as... Figure 6 and Figure 7 As shown, in this embodiment, the ratio of the width W2 of the guide groove 272 to the width W1 of the insulating plate 21 is limited to... Within this range, when the ratio is 0.5, it can ensure that the insulation plate 21 has sufficient structural strength to resist the impact of airflow and prevent the electrode group 10 from moving around, and it can also provide a sufficiently wide guide groove 272 to facilitate the rapid collection and guidance of gas into the protective groove 213, reducing the problem of cell rupture caused by untimely venting. The venting of the cell meets the requirements and greatly improves the safety performance of the cell.

[0037] In this embodiment, if the above ratio is lower than If the width ratio of the guide channel 272 to the insulating plate 21 is too small, the cross-sectional area of ​​the guide channel 272 will be insufficient. When thermal runaway occurs in the energy storage cell and the gas production rate and volume are high, the narrow guide channel 272 will restrict gas flow, causing untimely venting of the guide channel 272, resulting in a sharp increase in internal pressure of the cell and potentially leading to a safety hazard of casing 40 rupture. If the above ratio is higher than... At that time, the width of the guide groove 272 was too large, resulting in the insulation plate 21 itself being too narrow. After the cell explosion-proof valve 23 was opened to release pressure and exhaust gas, under the impact of the high temperature and high pressure airflow inside the cell, the insulation plate 21, due to its insufficient structure and weak strength, was prone to breakage or collapse and deformation. Not only could it not maintain the exhaust channel 43, but it also increased the risk of the pole group 10 moving towards the explosion-proof valve 23, causing the front end of the pole group 10 to block the explosion-proof valve 23, greatly reducing the exhaust effect of the explosion-proof valve 23.

[0038] like Figures 3 to 10 As shown, this application also includes a protective plate 70; The protective plate 70 is disposed in the protective groove 213, and its 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 that of the protective part 211.

[0039] In one embodiment, the protective plate 70 is embedded in the 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 easily moving within the protective groove 213. The protective plate 70 is provided with several through holes 74 so that the fluid in the protective groove 213 can 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. The protective plate 70 selected in this embodiment 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.

[0040] In the event of thermal runaway of the battery cell, the airflow inside the cell first passes through the flow holes 214 on the protective part 211 and enters the protective groove 213. As the temperature inside the battery cell rises rapidly, the plastic material of the protective part 211 softens and deforms due to reaching its melting temperature, losing its original structural rigidity. At this time, the electrode assembly 10 moves towards the top cover of the battery cell 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, on the one hand, blocks the movement of the electrode assembly 10 and prevents the electrode assembly 10 from sticking to the explosion-proof valve 23; on the other hand, the through holes 74 on the protective plate 70 still maintain geometric stability at high temperatures. In this embodiment, the top cover of the battery cell utilizes the difference in melting points between the materials of the protective part 211 and the protective plate 70. At the same time, the spatial layout of the protective plate 70 in the protective groove 213 ensures that high-temperature and high-pressure gas can pass through the through hole 74 and impact the explosion-proof valve 23, maintaining a constant cross-section of the internal flow channel of the battery cell and eliminating the safety hazard of the electrode group 10 blocking the explosion-proof valve 23 under extreme working conditions of the battery cell.

[0041] like Figure 6 , Figure 9 and Figure 10 As shown, the protective plate 70 includes a base plate 73 and protrusions 71 and countersunk plates 72 disposed on the edge of the base plate 73 and distributed in an alternating manner. The boss 71 abuts against the side of the metal plate 22 facing the protective groove 213; The settling platform 72 is connected to the side of the protective part 211 facing the metal plate 22.

[0042] 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.

[0043] like Figure 9As 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.

[0044] In this embodiment, a boss 71, a recessed platform 72, and a corner platform 75 are provided in the third 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.

[0045] like Figure 5 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 in 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 satisfy the function of locking the protective plate 70.

[0046] like Figure 7 As 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, so that when the protective plate 70 is assembled in the protective groove 213, the countersunk platform 72 of 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, so that the protective plate 70 can be firmly locked in the protective groove 213 to prevent the protective plate 70 from moving in the protective groove 213.

[0047] like Figures 4 to 7 , Figure 9 and Figure 10 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: .

[0048] 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.

[0049] 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.

[0050] like Figure 10 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: ; .

[0051] 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.

[0052] like Figures 3 to 6 , Figure 9 and Figure 10 As shown, the substrate 73 is rectangular with a length of A2 and a width of B2. The area of ​​the substrate 73 is: ; 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 holes 74 is S3, and the cross-sectional area of ​​the flow channel between the protective plate 70 and the metal plate 22 is S4. Figure 5 As shown, we have:

[0053]

[0054] .

[0055] 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. At this time, the effective opening area of ​​the explosion-proof valve 23 is S0; Figure 10 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 10 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 area of ​​a single via 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 5 The area shown by the dashed line is the flow channel between the protective plate 70 and the metal plate 22, denoted as S4.

[0056] like Figure 10 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.

[0057] 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.

[0058] The formula defines the ratio of the total area of ​​the vias 74 on the protective plate 70 to the total area of ​​the substrate 73. If it is less than 0.2, the current resistance inside 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.

[0059] As one embodiment, if the substrate 73 area is set in this embodiment 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.

[0060] 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.

[0061] 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.

[0062] like Figures 3 to 5 As shown, the distance between the boss 71 and the explosion-proof valve 23 in the first direction (length direction) is C, and the distance in the second direction (width direction) is D, satisfying: .

[0063] As an optional implementation, this embodiment uses the length direction of the metal plate 22 as the first direction, the width direction of the metal plate 22 as the second direction, and a third direction perpendicular to the surface of the metal plate 22, making the first, second, and third directions mutually perpendicular. When the internal pressure of 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.

[0064] 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.

[0065] like Figure 7 and Figure 8 As shown, a flow channel 215 is also provided between the protective part 211 and the metal plate 22; The flow channel 215 is used to connect the inner and outer spaces of the protective channel 213; The insulating plate 21 is provided with support portions 26 at both ends in the first direction; The support portion 26 protrudes from the insulating plate 21, and the top surface of the support portion 26 is flush with the top surface of the protective portion 211. The support portion 26 is provided with an air inlet 265 that communicates with the guide groove 272.

[0066] like Figures 6 to 8As shown, as an optional implementation, this embodiment can also reserve an air passage 266 on the support part 26. The air passage 266 can be optionally set 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 is reserved on the periphery of the support part 26, so that the high temperature and high pressure gas located at the end can flow to the flow hole 214 through the air passage 266 surrounding the periphery of the support part 26. The flow groove 215 can be used as a bypass channel, so that the gas in the air passage 266 can bypass the flow hole 214 and flow into the protective groove 213 through the flow groove 215, which further reduces the exhaust resistance.

[0067] The support portion 26 includes a support frame 262, a recessed groove 261, a through hole 263, a rib 264, an air inlet 265, and the aforementioned air passage 266. The support frame 262 and the protective portion 211 are assembled via a connecting plate 27. Preferably, the support frame 262, connecting plate 27, and protective portion 211 are integrally formed to constitute the insulating plate 21 of this application. One side of the connecting plate 27 can be fixed to the metal plate 22 with rivets, allowing communication between the recessed groove 261 and the protective groove 213 through the gap between the connecting plate 27 and the metal plate 22. The recessed groove 261 is located on the side of the support frame 262 facing the metal plate 22, similar to the concave structure of the protective portion 211 towards the metal plate 22. To further improve the support strength of the support frame 262, a vertical rib 264 is provided in the internal space of the recessed groove 261 to enhance the support strength of the support frame 262. The stability of the metal plate 22 is improved, and 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 connecting the sink 261 is also opened at the bottom of the sink 261. In this embodiment, the air inlet 265 is used to connect the guide groove 272. The gas in the dead corner area at both ends of the battery cell top cover flows into the protective groove 213 through the air inlet 265 and the guide groove 272 in sequence, thereby further increasing the gas flow path. At the same time, the gas can also flow into the protective groove 213 from the air inlet 265, the air passage 266 and the flow groove 215. The gas accumulated in the protective groove 213 is finally ejected from the explosion-proof valve 23.

[0068] This embodiment, through the aforementioned structural limitations, forms a combination of an air inlet 265 and a through hole 263 on the support portion 26. This facilitates the communication of gas from the side of the battery cell through the air inlet 265 and the through hole 263. Furthermore, the gas in the sink 261 also flows through the air passage 266 around the support portion 26 to the flow hole 214 and flow groove 215 of the protective portion 211. In addition, this embodiment can further widen the bypass flow path of the gas through the flow branches of the air inlet 265, the guide groove 272, and the protective groove 213. This allows the gas to flow into the protective groove 213 in various ways, reducing the gas resistance of high-temperature and high-pressure gas when flowing to the explosion-proof valve 23. It also ensures the gas emission capacity of the dead zone area of ​​the battery cell and avoids the situation where the electrode group 10 blocks the explosion-proof valve 23 due to untimely gas emission.

[0069] like Figures 5 to 8 As shown, the total area of ​​the guide hole 271 and the flow passage 214 is denoted as S7; the effective opening area of ​​the explosion-proof valve 23 is S0; and the total area of ​​the air inlet 265 and the flow passage 215 is S8. Therefore: .

[0070] As an optional implementation, in this embodiment, the total area of ​​the guide hole 271 and the flow passage 214 is denoted as S7. This S7 is then added to the total area S8 of the air inlet 265 and the flow groove 215, and finally compared with the effective opening area S0 of the explosion-proof valve 23. This ratio is then limited to... Within the range. This embodiment limits the relationship between various areas and the effective opening area S0 of the explosion-proof valve 23. For example, when the intermediate value of 1.25 is taken, it ensures that the gas can quickly gather to the explosion-proof valve 23 and be discharged outdoors after it is generated, avoiding the cell pressure rupture; it also limits excessive opening, ensuring that the overall strength of the insulation plate 21 meets the requirements, and effectively avoids the problem of the electrode group 10 moving and blocking the explosion-proof valve 23.

[0071] In this embodiment, if the above relationship is lower than the lower limit of 1.15, the current-carrying area (S7+S8) inside the battery cell is relatively small compared to the effective opening area (S0) of the explosion-proof valve 23. Even if the explosion-proof valve 23 can open normally, the large amount of high-pressure gas generated cannot pass through the internal opening in time to reach the explosion-proof valve 23 for pressure relief, which can easily lead to excessively high local gas pressure, ultimately causing the casing 40 to expand or even rupture and fail. If the above relationship... An excessively large overcurrent area (S7+S8) inside the battery cell means that the opening ratio on the insulation plate 21 is too high, which will lead to a decrease in the mechanical strength of the insulation plate 21. After the explosion-proof valve 23 is opened to release pressure and exhaust gas, the insulation plate 21 is easily damaged or crushed under the impact of high temperature and high pressure airflow, which will cause the electrode group 10 to move towards the explosion-proof valve 23 and block the valve port, thus reducing the exhaust effect.

[0072] like Figure 2 , Figure 6 , Figure 7 , Figure 11 and Figure 13 As shown, this application also discloses a battery cell, including an electrode assembly 10, an insulating film 30, a housing 40, a first cover plate 20, and a second cover plate 50; the insulating film 30 is sleeved on the outer wall of the electrode assembly 10; the housing 40 has a storage cavity 44, the interior of which accommodates the electrode assembly 10 carrying the insulating film 30; the first cover plate 20 and the second cover plate 50 are respectively assembled at the two open ends of the housing 40; wherein, the first cover plate 20 adopts the above-mentioned battery cell top cover.

[0073] As an optional implementation, after the electrode assembly 10 is wound or stacked and covered with an insulating film 30, it is inserted into the storage cavity 44 from one end of the housing 40; in order to prepare a large-capacity energy storage cell, this embodiment uses the above-mentioned top plate to complete the end encapsulation.

[0074] The first cover plate 20 adopts the cell top cover of the above embodiment. It has connecting plates 27 on both sides of the protective part 211. The connecting plates 27 and the metal plate 22 define a guide groove 272. The guide groove 272 serves as a bridge connecting the air inlet 265 and the protective groove 213, so that the high temperature and high pressure gas generated inside the cell can flow in through the air inlet 265 at both ends of the cell top cover, and then flow into the protective groove 213 through the guide groove 272. In addition, the two ends of the cell top cover are also provided with air passages 266 surrounding the support part 26. The high temperature and high pressure gas can also flow into the protective groove 213 through the air passages 266 and the flow groove 215. The two branches are also connected through the guide hole 271. This embodiment sets up multiple interconnected branches that can guide high-temperature and high-pressure gas to the protective groove 213. This allows the gas inside the battery cell to be guided to the protective groove 213 in a timely manner. Then, the explosion-proof valve 23 will discharge the gas accumulated in the protective groove 213 in a timely manner, ensuring that the gas inside the battery cell is not enough to push the electrode group 10, so as to prevent the electrode group 10 from blocking the explosion-proof valve 23 and affecting the safe venting of the battery cell.

[0075] like Figure 2 As shown, the second cover plate 50 is used to mount the electrode terminals 60 for connection 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.

[0076] In actual process formulation, the amount A of lithium supplementer added (i.e., its mass percentage in the cathode material) is limited to: ; like Figure 10 , Figure 11 and Figure 13 As shown, H is the total height of the protective plate 70. S1 is the outer contour area of ​​the protective plate 70 (S1), as shown in the above embodiment; L0 is the length of the battery cell, as shown in the above embodiment. Figure 11 and Figure 13 As shown.

[0077] 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., large L0) and high lithium replenishment doping (large A ratio), the volume of the protective plate 70 ( 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.

[0078] 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: Opening pressure of explosion-proof valve 23 Set as: ; The burst pressure of the casing 40 in its free state is Set as: ; Furthermore, the two satisfy the linkage equation in the system design: .

[0079] This embodiment requires the burst pressure of the shell 40 in its free state. 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.

[0080] like Figure 11 and Figure 13 As shown, in order to further adapt to the drastic expansion of electrode assembly 10 and the high-flow-rate exhaust requirements caused by the high-doping lithium supplement, the relationship between the core components of the top plate is further defined based on the above top plate embodiment: Let the length of the opening area of ​​the housing 40 (i.e., the area where the first cover plate 20 is assembled) be B0 and the width be A0. Then, the area of ​​the top 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: .

[0081] 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.

[0082] 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 in the top cover of the battery cell.

[0083] like Figure 2 , Figure 3 , Figure 8 , Figures 11 to 13 As shown, the housing 40 has convex strips 41 and concave strips 42 alternately arranged on at least one side wall; When the electrode assembly 10 is assembled into the storage cavity 44, the concave strip 42 abuts against the electrode assembly 10 inward, and the electrode assembly 10 and the convex strip 41 define an exhaust channel 43, the total cross-sectional area of ​​the exhaust channel 43 is S5; The effective opening area of ​​the explosion-proof valve 23 is S0, and the opening pressure of the explosion-proof valve 23 is... The burst pressure of the shell 40 in its free state is Then we have: .

[0084] As an alternative implementation, given a high gas generation rate from the battery cell, the vertical exhaust path directly below the explosion-proof valve 23 alone is insufficient to meet the transient pressure relief requirements. Therefore, in this embodiment, the flow channels of the sidewalls and the edge structure of the top plate of the housing 40 are modified.

[0085] The housing 40 has two large surfaces and two small surfaces arranged opposite to each other; one or more exhaust channels 43 are provided on the small surfaces of the housing 40, so that the exhaust channels 43 can discharge high-pressure gas into the protective groove 213 below the explosion-proof valve 23 from the side of the electrode assembly 10; wherein, the small surfaces of the housing 40 have staggered convex strips 41 and concave strips 42, such as Figure 12 As shown, two protruding strips 41 and one concave strip 42 are preferably provided, with the concave strip 42 located in the middle. When the electrode assembly 10 with the insulating film 30 is installed into the housing 40, the concave strip 42 extends towards the electrode assembly 10, causing it to fit tightly against the outer wall of the electrode assembly 10. Meanwhile, a vertically upward side exhaust channel 43 is formed between the protruding strips 41 and the electrode assembly 10. After the electrode assembly 10 is assembled into the housing 40, the protruding strips 41 on the small surface of the housing 40 and the air passage 266 around the support 26 achieve fluid communication in a third direction. Here, the third direction refers to the direction perpendicular to the surface of the metal plate 22, or the length direction of the housing 40.

[0086] The first cover plate 20 also needs to be adjusted according to the structure of the concave strip 42 and the convex strip 41, specifically: 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.

[0087] When the battery cell experiences 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 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 upwards, 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. 3; Of course, the gas flowing into the exhaust channel 43 can also flow into the protective groove 213 through the air inlet 265 and the guide groove 272 at the end of the top plate. The gas in the guide groove 272 can also flow into the air passage 266 through the guide hole 271, and then flow into the protective groove 213 from the air passage 266 and the flow groove 215. The whole process can realize the parallel exhaust action of the main airflow and multiple branches, which greatly reduces the gas flow resistance inside the cell and promotes the rapid discharge of gas generated in the dead area inside the cell.

[0088] In this embodiment, an auxiliary exhaust channel 43 and a guide groove 272 are additionally constructed on the basis of the original battery cell. Even if the expansion of other positions of the electrode group 10 causes local air resistance, the electrode group 10 can still ensure high-speed airflow conduction by relying on the auxiliary exhaust channel 43 and the guide groove 272, which minimizes the pressure stagnation time and further improves the reliability of the battery cell in long-cycle energy storage devices.

[0089] In this embodiment, the effective opening area S0 of the explosion-proof valve 23 and the opening pressure of the explosion-proof valve 23 are used. As the denominator, the burst pressure of the shell 40 in its free state. Using the total cross-sectional area S5 of exhaust channel 43 as the numerator, form the corresponding relational formula. And limit the scope of this relation to The above parameter range ensures that, during cell safety testing, the gas generated by thermal runaway is rapidly guided along the exhaust channel 43 (i.e., the total cross-sectional area is S5) between the electrode group 10 and the casing 40, and that the casing 40 withstands the burst pressure in a free state. The opening pressure of the explosion-proof valve 23 is reached. The explosion-proof valve 23 was opened. Test results showed that the explosion-proof valve 23 could be opened normally, and there was no problem of the casing 40 cracking due to untimely venting. The cell venting fully meets the high safety requirements of large-capacity energy storage scenarios.

[0090] If the above-mentioned relationship in this embodiment is lower than At this time, it means the burst pressure of the shell 40 in its free state. The pressure is too low, or the total cross-sectional area S5 of the exhaust channels 43 is too small. When thermal runaway occurs in the energy storage cell, due to the narrow exhaust channels 43 or insufficient structural strength of the casing 40, the high-pressure gas generated inside may not have time to be successfully conducted to the explosion-proof valve 23 and break through the valve to release pressure, thus failing to reach the opening pressure of the explosion-proof valve 23. The local stress on the shell 40 already exceeded its own burst pressure in its free state. This can easily lead to accidents where the explosion-proof valve 23 has not yet functioned before the housing 40 bulges and ruptures prematurely. If the relationship in the above embodiment is higher than... This means that the pressure relief capacity of the explosion-proof valve 23 is relatively limited, that is, the effective opening area S0 of the explosion-proof valve 23 is too small or the opening pressure of the explosion-proof valve 23 is too high. If the burst pressure F1 of the casing 40 in its free state is designed to be too low, although the casing 40 has strong pressure resistance, the massive amount of high-temperature gas during thermal runaway cannot be exhausted in time, and prolonged high-temperature smoldering will exacerbate the heat spread inside the cell; on the other hand, if the burst pressure of the casing 40 in its free state is increased... Simply increasing the thickness of the casing by 40mm will lead to a significant increase in the overall weight of the battery cell and a reduction in the usable internal volume, sacrificing the energy density that is extremely important for the energy storage cell and resulting in over-design.

[0091] This application also discloses an energy storage device equipped with the aforementioned battery cells.

[0092] 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 top cover of the individual battery cell prevents the spread of thermal runaway between adjacent battery cells, thereby improving the system-level fire safety redundancy of the entire energy storage base station.

[0093] Working principle: When a short circuit or overcharge triggers thermal runaway in the electrode group 10 inside the battery cell, the electrolyte inside the battery cell rapidly vaporizes and generates a large amount of high-temperature, high-pressure mixed gas flow. The gas flow impacts the battery cell from bottom to top in a directional manner. The main gas flow first impacts the insulating plate 21 and flows into the protective groove 213 through the flow holes on the insulating plate 21. Part of the gas flow is generated from the side of the battery cell and flows into the air passages 266 at both ends of the top cover of the battery cell through the exhaust channels 43 on both sides of the housing 40 to form a surrounding flow. The gas flow is divided into two parts: one part flows through the air inlet 265 and the guide groove 272 at the end of the top plate into the protective groove 213; the gas in the guide groove 272 can also flow through the guide hole 271 into the air passage 266, and then from the air passage 266 and the flow groove 215 into the protective groove 213; the other part of the gas flow flows directly from the air passage 266 and the flow groove 215 into the protective groove 213. The gas flow that gathers in the protective groove 213 will break through the weak explosion-proof valve 23 to complete the safe discharge of the gas.

[0094] During the above-mentioned emission process, as the temperature continues to rise until the airflow temperature exceeds the melting point of the plastic, the protective part 211 begins to soften and gradually deforms. At this time, the electrode assembly 10 is driven by the pressure difference of the rapid expansion inside the cell to violently surge upward. The surging electrode assembly 10 will collide with and be pressed against the protective plate 70. The protrusion 71 of the protective plate 70 will evenly transfer the impact load of the electrode assembly 10 to the metal plate 22 substrate, and the protective plate 70 itself maintains a small amount of elastic deformation without collapsing. The protective plate 70 is used to limit the electrode assembly 10 from continuing to move towards the explosion-proof valve 23.

[0095] Although the protective part 211, made of plastic, is damaged due to high temperature and pressure, the high-pressure airflow can still pass smoothly through the through hole 74 on the protective plate 70 and the lateral auxiliary channel formed by the gap between the boss 71 and the countersunk plate 72, under the support and restriction of the protective plate 70. Finally, it converges at high velocity and impacts the explosion-proof valve 23 on the metal plate 22. When the converged pressure exceeds the threshold of the explosion-proof valve 23, the valve plate bulges instantly and breaks along the preset groove to open the valve, and the internal high-pressure gas is safely discharged into the external atmosphere, completing the safe depressurization of the battery cell. In addition, during the depressurization process of the battery cell, in addition to the main airflow of the protective part 211, this application also adds auxiliary flow paths such as the exhaust channel 43, the air inlet 265, the guide groove 272, and the protective groove 213, as well as auxiliary flow paths such as the exhaust channel 43, the air passage 266, the flow groove 215, and the protective groove 213. The two flow paths mentioned above are connected through the guide hole 271, thereby increasing the branch of gas flow. This not only connects to the protective groove 213 over a large area of ​​the battery cell, allowing gas in the dead zone of the battery cell to be quickly discharged to the protective groove 213, but also reduces the overall gas flow resistance, thereby reducing the tendency of the electrode group 10 to move towards the explosion-proof valve 23. Even if the electrode group 10 blocks the explosion-proof valve 23, this application also uses the protective plate 70 to prevent the electrode group 10 from moving upward, and the through hole 74 on the protective plate 70 also ensures the exhaust capacity of the battery cell.

[0096] 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 top cover, characterized in that, include: Metal sheet; An explosion-proof valve is mounted on the metal plate; An insulating plate is attached to one side of the metal plate; The protective part is connected to the insulating plate and is positioned opposite to the explosion-proof valve. The protective part protrudes away from the metal plate and together with the metal plate, defines a protective groove. The protective part has a flow hole that communicates with the protective groove. A connecting plate is disposed on both sides of the protective part along the first direction and protrudes from the surface of the insulating plate. The height at which the connecting plate protrudes from the insulating plate is lower than the protrusion height of the protective part. The flow channel is defined by the connecting plate and the metal plate, and the flow channel is used to connect the two ends of the top cover of the battery cell to the protective channel; The first direction is the length direction of the metal plate; It also includes protective panels; The protective plate is disposed in the protective groove, and its side facing the explosion-proof valve abuts against the metal plate; the protective plate has through holes, so that airflow flows through the through holes and the through holes to the explosion-proof valve; The melting point of the protective plate is higher than that of the protective part.

2. The cell top cover as described in claim 1, characterized in that, The connecting plate has at least one flow guide hole, which is used to connect the inner and outer spaces of the flow guide groove.

3. The cell top cover as described in claim 1, characterized in that, The width of the guide channel is W2, and the width of the insulating plate is W1, then: 。 4. The cell top cover as described in claim 1, characterized in that, The protective plate includes a base plate and protrusions and recesses disposed on the edge of the base plate 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.

5. The cell top cover as described in claim 4, characterized in that, The protective groove is also provided with a limiting component, and the inner wall of the protective groove is provided with a limiting part; The limiting member engages with the recessed platform, and the recessed platform is embedded within the limiting part.

6. The cell top cover as described in claim 2, characterized in that, A flow channel is also provided between the protective part and the metal plate; The flow channel is used to connect the inner and outer spaces of the protective channel; The insulating plate is provided with support portions at both ends in the first direction; The support portion protrudes from the insulating plate, and the top surface of the support portion is flush with the top surface of the protective portion; The support portion is provided with an air inlet that connects to the guide groove.

7. The cell top cover as described in claim 6, characterized in that, The total area of ​​the guide hole and the flow passage is denoted as S7; the effective opening area of ​​the explosion-proof valve is S0; and the total area of ​​the air inlet and the flow passage is S8. Then: 。 8. A battery cell, characterized in that, include: pole group; An insulating film is fitted onto the outer wall of the electrode assembly; The housing has a storage cavity, the interior of which accommodates the electrode assembly carrying the insulating film; The first cover plate and the second cover plate are respectively assembled at the two open ends of the housing; Wherein, the first cover plate is a cell top cover as described in any one of claims 1 to 7.

9. The battery cell as described in claim 8, characterized in that, The housing has alternating convex and concave ribs on at least one side wall; When the electrode assembly is assembled into the storage cavity, the concave strip abuts against the electrode assembly inward, and the electrode assembly and the convex strip define an exhaust channel, the total cross-sectional area of ​​the exhaust channel being S5; The effective opening area of ​​the explosion-proof valve is S0, and the opening pressure of the explosion-proof valve is... The burst pressure of the shell in its free state is Then we have: 。 10. An energy storage device, characterized in that, It is equipped with the battery cell as described in claim 8 or 9.

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