End cover assembly, energy storage device and energy storage system

Abstract

The embodiment of the invention provides an end cover assembly, an energy storage device and an energy storage system, the end cover assembly comprises an end cover, lower plastic, an explosion-proof support and two supporting frames, and the lower plastic comprises first lower plastic and two second lower plastic; the explosion-proof support and the two supporting frames are each provided with a ventilation structure, the first lower plastic and the two second lower plastic are connected to one face of the end cover in a stacked mode in the thickness direction of the end cover assembly, the two second lower plastic are located at the two ends of the end cover in the length direction, and the first lower plastic is located between the two second lower plastic and is spaced from the two second lower plastic. The explosion-proof support is arranged on the side, back to the end cover, of the first lower plastic and connected with the end cover, and the two supporting frames are stacked on the sides, back to the end cover, of the two second lower plastic respectively and connected with the end cover. The ventilation direction of the ventilation structure of the anti-explosion support and the ventilation direction of the ventilation structures of the two supporting frames are parallel to the length direction of the end cover. And the explosion-proof bracket and the support frame are both used for abutting against the battery cell.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to an end cap assembly, an energy storage device, and an energy storage system. Background Technology

[0002] With the rapid development of the new energy industry, the market demand for batteries continues to grow. However, when existing batteries experience thermal runaway, a large amount of high-temperature gas is generated inside the battery. During the process of venting this high-temperature gas, the lower insulation component can melt and deform, or even catch fire. At the same time, the high-temperature gas pushes the wound core inside the battery upwards towards the lower insulation component, which can easily block the venting channels. This makes it difficult for a large amount of gas inside the battery to be released in time, posing a significant safety hazard. Summary of the Invention

[0003] This application provides an end cap assembly, an energy storage device, and an energy storage system, which enhances the venting performance of the end cap assembly and improves the safety performance of the energy storage device.

[0004] In a first aspect, embodiments of this application provide an end cap assembly for use in an energy storage device, the end cap assembly comprising: End cap; The lower plastic, comprising a first lower plastic and two second lower plastics; The device includes an explosion-proof bracket and two support frames. The explosion-proof bracket has a first ventilation structure, and the two support frames have second ventilation structures. Along the thickness direction of the end cap assembly, a first lower plastic and two second lower plastics are each disposed on one surface of the end cap and are stacked and connected to the end cap. The two second lower plastics are located at both ends of the end cap along its length direction. The first lower plastic is located between the two second lower plastics and is spaced apart from them. The explosion-proof bracket is installed on the side of the first lower plastic facing away from the end cap, and passes through the first lower plastic and connects to the end cap. The two support frames are respectively stacked on the side of the two second lower plastics facing away from the end cap, and respectively pass through the two second lower plastics and connect to the end cap. The ventilation direction of the first ventilation structure and the second ventilation structure is parallel to the length direction of the end cap assembly. Both the explosion-proof bracket and the support frame are used to abut against the battery cell of the energy storage device, wherein the melting point of both the explosion-proof bracket and the support frame is greater than the melting point of the lower plastic.

[0005] In one embodiment, the explosion-proof bracket includes a body section, two first abutment sections, and two mounting sections. Along the width direction of the end cap assembly, the two first abutment sections are respectively connected to both sides of the body section, and each mounting section is connected to the side of one of the first abutment sections away from the body section. Each first abutment section is set at an angle to the body section and the mounting section. Both mounting sections pass through the first lower plastic and are connected to the end cap. The two first abutment sections are limited by the first lower plastic. Both the two first abutment sections and the body section are used to abut against the battery cell. Each of the first abutting sections has a first through groove, and the two first abutting sections and the body section form a second through groove. The second through groove is located between the two first through grooves. The openings of the two first through grooves in the thickness direction are arranged opposite to the openings of the second through groove in the thickness direction. Both the two first through grooves and the second through groove include openings in the width direction of the first abutting section. The first ventilation structure includes the two first through grooves and the second through groove.

[0006] In one embodiment, the side of the second lower plastic facing away from the end cap has a snap-fit ​​protrusion; The support frame includes multiple assembly sections, each assembly section including a first assembly section and two second assembly sections. Along the length direction of the assembly sections, the first assembly section is located between the two second assembly sections, and the first assembly section and the two second assembly sections are spaced apart. The first assembly section is provided with a snap-fit ​​plate, which is located on one side of the width direction of the assembly section. The snap-fit ​​plate snaps with the snap-fit ​​protrusion. The second assembly section passes through the second lower plastic and is connected to the end cap. Both the first assembly section and the second assembly section are used to abut against the battery cell.

[0007] In one embodiment, the second assembly section includes a support plate and a vertical plate. The vertical plate is connected to the support plate and disposed on the edge of the support plate. Along the thickness direction of the end cap assembly, the support plate is opposite to and spaced apart from the end cap. The vertical plate is connected to the end cap.

[0008] In one embodiment, the support frame further includes two second abutment sections, and along the length direction of the support frame, a second abutment section is connected between the first assembly section and each of the second assembly sections; the second abutment section abuts against the second lower plastic and is used to abut against the battery cell; Each of the second abutment sections forms two third through slots and a fourth through slot; the fourth through slot is located between the two third through slots, the openings of the two third through slots in the thickness direction are arranged opposite to the openings of the fourth through slot in the thickness direction, and both the two third through slots and the fourth through slot include openings in the width direction of the second abutment section, and the second ventilation structure includes the two third through slots and the fourth through slot.

[0009] In one embodiment, the support frame further includes flow guide holes that extend through both surfaces of the support frame in the thickness direction.

[0010] In one embodiment, the end cap includes an explosion-proof hole that penetrates both surfaces of the end cap in the thickness direction; The first lower plastic includes a connecting hole that extends through both sides of the first lower plastic in the thickness direction. The first lower plastic is disposed opposite to the explosion-proof hole of the end cap in the thickness direction of the end cap assembly. The connecting hole and the explosion-proof hole are opposite to and connected to each other. The body segment includes a vent hole, the body segment is opposite to and spaced from the first lower plastic in the thickness direction of the end cap assembly, and the vent hole is opposite to and connected to the connecting hole.

[0011] In one embodiment, the end cap has a recessed limiting groove on the surface facing the lower plastic, and the first lower plastic has a protruding first limiting post on the surface facing the end cap, the first limiting post being received in the limiting groove. The first lower plastic part has a second limiting post protruding from the surface facing away from the end cap. The explosion-proof bracket includes a limiting hole that penetrates both surfaces of the explosion-proof bracket in the thickness direction. The second limiting post is received in the limiting hole.

[0012] In one embodiment, the end cap further includes a liquid injection hole, which penetrates both surfaces of the end cap in the thickness direction and is located on one side of the explosion-proof hole along the length direction of the end cap assembly, and is spaced apart from the explosion-proof hole. The first lower plastic has a liquid distribution part protruding on the side surface facing away from the end cap, and the first lower plastic has a liquid distribution hole. The liquid distribution part and the liquid distribution hole are connected. The liquid distribution part covers the injection hole, and the injection hole and the liquid distribution hole are connected.

[0013] In one embodiment, the end cap further includes an insulating layer covering the surface of the end cap facing the lower plastic, the explosion-proof bracket and the support frame are made of metal, and the outer surfaces of the explosion-proof bracket and the support frame are completely covered with insulating material.

[0014] Secondly, embodiments of this application provide an energy storage device. The energy storage device includes a housing, a battery cell, an insulating film, and an end cap assembly. The battery cell is housed within the housing, the end cap assembly is mounted on one side of the battery cell and sealed to the housing, the explosion-proof bracket and the support frame both abut against the battery cell, and the insulating film covers the periphery and bottom surface of the battery cell and is connected to the lower plastic.

[0015] Thirdly, embodiments of this application provide an energy storage system. The energy storage system includes the energy storage device.

[0016] In related technologies, when existing batteries experience thermal runaway, a large amount of high-temperature gas is generated inside the battery. During the process of the high-temperature gas being discharged from the battery, it can cause the lower insulation to melt, deform, or even ignite, resulting in the failure of the supporting function of the core. At the same time, the high-temperature gas pushes the core inside the battery upward towards the lower insulation, blocking the exhaust channel. This makes it difficult for a large amount of gas inside the battery to be discharged in time, which can lead to problems such as the battery cracking or even the battery itself, posing a great safety hazard.

[0017] In this embodiment, by providing an explosion-proof bracket and two support frames on the side of the lower plastic facing away from the end cap, the lower plastic will melt during thermal runaway of the energy storage device. The explosion-proof bracket and the two support frames can support the battery cell, preventing it from moving towards the end cap assembly along the height direction of the energy storage device, thus avoiding the battery cell blocking the exhaust channel and improving the exhaust performance of the end cap assembly and the safety of the energy storage device. Moreover, both the explosion-proof bracket and the support frames have multi-bending structures. The first and second through slots of the explosion-proof bracket form a first ventilation structure, and the first and second through slots penetrate both sides of the width direction of the explosion-proof bracket. At the same time, the third and fourth through slots of the support frames form a second ventilation structure, and the third and fourth through slots penetrate both sides of the width direction of the support frames. This allows gas generated from the side of the shell and the battery cell to flow from the second ventilation structure of the support frame and the first ventilation structure of the explosion-proof bracket to the explosion-proof structure of the end cap, ensuring the exhaust efficiency of the end cap assembly. Even if the energy storage device experiences thermal runaway and the lower plastic fails, the bracket assembly can still ensure that the end cap assembly has sufficient exhaust channels for exhaust, improving the safety performance of the energy storage device.

[0018] Furthermore, the lower plastic in this application is divided into multiple segments, which not only saves material of the lower plastic and reduces the risk of the lower plastic melting or even igniting during thermal runaway of the battery cell, but also reduces the weight and volume of the lower plastic, achieving lightweighting of the lower plastic, which in turn helps to achieve lightweighting of energy storage devices. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments or background art of this application, the accompanying drawings used in the embodiments or background art of this application will be described below.

[0020] Figure 1 This is a schematic diagram of the structure of an energy storage system according to an embodiment of this application; Figure 2 for Figure 1 A schematic diagram of the energy storage device in the energy storage system shown. Figure 3 for Figure 2 The diagram shows the exploded structure of the energy storage device. Figure 4 for Figure 3 A schematic diagram of the axial structure of the end cap assembly of the energy storage device shown; Figure 5 for Figure 3 The diagram shows an exploded view of the end cap assembly. Figure 6 for Figure 4 An exploded view of the end cap assembly of the energy storage device shown. Figure 7 for Figure 6 A schematic diagram of the end cap structure of the end cap assembly shown; Figure 8 for Figure 5 The diagram shows the structure of the lower plastic part of the end cap assembly. Figure 9 for Figure 6 The diagram shows the structure of the lower plastic part of the end cap assembly. Figure 10 for Figure 5 The diagram shows the structure of the explosion-proof bracket of the end cap assembly bracket assembly. Figure 11 for Figure 6 The diagram shows the structure of the explosion-proof bracket of the end cap assembly bracket assembly. Figure 12 for Figure 5 A schematic diagram of the support frame of the end cap assembly bracket assembly shown; Figure 13 for Figure 6 A schematic diagram of the support frame of the end cap assembly bracket assembly shown; Figure 14 for Figure 4 The diagram shows a partial structural schematic of the end cap assembly. Figure 15 for Figure 14 The diagram shows a partial structure of the end cap assembly along AA. Figure 16 for Figure 14 The diagram shows a partial structure of the end cap assembly along the BB line.

[0021] The terms corresponding to the reference numerals in the figures are as follows: Energy storage system 4000, high-voltage cable 4100, first power conversion device 4200, second power conversion device 4300, energy storage device 1000, housing 200, receiving cavity 202, opening 201, end cap assembly 100, end cap 10, top surface 11, bottom surface 12, assembly groove 13, first pole post through hole 14, liquid injection hole 15, explosion-proof hole 16, limiting groove 17, lower plastic 20, body H, hot melt edge r, upper surface a, lower surface b, perforation K, first lower plastic 21, first body H1, first upper surface Surface a1, first lower surface b1, first main body portion H11, first protruding portion H12, liquid distribution portion 211, liquid distribution hole 212, connecting hole 213, first through hole 214, first limiting post 215, second limiting post 216, first hot melt edge r1, second lower plastic 22, second body H2, second upper surface a2, second lower surface b2, second main body portion H21, second protruding portion H22, mounting groove 221, limiting protrusion 222, limiting surface 2221, second pole post through hole 223, second hot melt edge r2, third hot melt edge r3, second through hole 22 4. Snap-fit ​​protrusion 225, bracket assembly 30, explosion-proof bracket 31, first surface 311, second surface 312, first side surface 313, first through groove 314, first protrusion 315, body section m, vent hole 316, guide plate 317, limiting hole 318, second through groove 319, first abutting section n, first abutting plate n1, first plate n2, first support plate n3, mounting section o, assembly plate o1, second plate o2, support frame 32, third surface 321, fourth surface 322, second side surface 323, third groove 324, third through groove 329, and so on. Four-way groove 325, second protrusion 326, third protrusion 327, first assembly section u, second support plate u1, first side plate u2, snap-fit ​​plate u3, first abutting surface u31, snap-fit ​​groove u32, second assembly section v, bearing plate v1, third side plate v2, upright plate v3, second abutting section w, third support plate w1, fourth side plate w2, second abutting plate w3, guide hole 328, explosion-proof valve 40, protective plate 50, pole post 60, pressure block 70, connecting piece 80, upper plastic 91, sealing ring 92, battery cell 300, first ventilation structure Q1, second ventilation structure Q2. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0023] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly specified. Furthermore, the terms "same," "equal," or "parallel" used below are all allowed to have certain tolerances.

[0024] It should be noted that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include at least one of those features.

[0025] Because the energy we need is highly time- and space-dependent, in order to utilize energy rationally and improve energy efficiency, it is necessary to store one form of energy in the same way or by converting it into another, and then release it in a specific energy form for future applications. Currently, the main way to generate green electricity is to develop green energy sources such as photovoltaics and wind power to replace fossil fuels. Currently, the generation of green electricity generally relies on solar, wind, and hydropower. However, wind and solar power are characterized by strong intermittency and large fluctuations, which can cause grid instability, insufficient power during peak hours, and excessive power during off-peak hours. Unstable voltage can also damage the power grid. Therefore, due to insufficient electricity demand or insufficient grid capacity, solving these problems requires energy storage. This involves converting electrical energy into other forms of energy through physical or chemical means and storing it. When needed, this energy can be converted back into electrical energy and released. Simply put, energy storage is like a large "power bank," storing electrical energy when solar and wind power are abundant and releasing the stored electricity when needed.

[0026] Taking electrochemical energy storage as an example, this solution provides an energy storage device for use in energy storage systems. The energy storage device is equipped with a set of chemical batteries, which mainly use the chemical elements in the batteries as energy storage media. The charging and discharging process is accompanied by the chemical reaction or change of the energy storage media. Simply put, the electrical energy generated by wind and solar energy is stored in the chemical batteries. When the use of external electrical energy reaches its peak, the stored electricity is released for use, or transferred to places with a shortage of electricity for use.

[0027] Current energy storage applications are quite widespread, including generation-side energy storage, grid-side energy storage, and consumption-side energy storage. The corresponding types of energy storage devices include: (1) Large-scale energy storage power stations applied to wind power and photovoltaic power stations can help renewable energy power generation meet grid connection requirements and improve the utilization rate of renewable energy. As a high-quality active / reactive power regulation power source on the power supply side, energy storage power stations can achieve load matching of power in time and space, enhance the absorption capacity of renewable energy, reduce instantaneous power changes, reduce the impact on the power grid, improve the absorption of new energy power generation, and are of great significance in power grid system backup, alleviating peak load power supply pressure and peak regulation and frequency regulation. (2) Energy storage containers applied on the grid side mainly function as peak shaving, frequency regulation and relief of grid congestion. In terms of peak shaving, they can realize peak shaving and valley filling of electricity load, that is, charging the energy storage battery when the electricity load is low and releasing the stored electricity during the peak electricity load period, thereby achieving a balance between power production and consumption. (3) Small-scale energy storage cabinets applied to the electricity consumption side mainly function as self-consumption of electricity, peak-valley price arbitrage, capacity cost management, and improving power supply reliability. Depending on the application scenario, electricity consumption-side energy storage can be divided into industrial and commercial energy storage cabinets, residential energy storage devices, energy storage charging piles, etc., which are generally used in conjunction with distributed photovoltaic power. Considering that photovoltaic power generation occurs during the day, while users generally have higher loads at night, configuring energy storage can better utilize photovoltaic power, improve the level of self-consumption, and reduce electricity costs. In addition, communication base stations, data centers, and other fields need to configure energy storage for backup power.

[0028] In some embodiments, please refer to Figure 1 , Figure 1 This is a schematic diagram of an energy storage system according to an embodiment of this application. Figure 1 The embodiments are illustrated using a shared energy storage scenario on the generation / distribution side as an example. The energy storage device 1000 of this application is not limited to its generation / distribution side energy storage scenario.

[0029] This application provides an energy storage system 4000. The energy storage system 4000 is used to supply power to electrical equipment. The energy storage system 4000 includes: a high-voltage cable 4100, a first power conversion device 4200, a second power conversion device 4300, and the energy storage device 1000 provided in this application. In some embodiments of the power generation scenario, the second power conversion device 4300 can be a wind power conversion device. Since the electricity generated by wind power conversion is volatile, random, and intermittent, the unstable electricity output by the wind power conversion device can be stored in the energy storage device 1000 through grid connection. The energy storage device 1000 is connected to the high-voltage cable 4100 and outputs smooth electricity to supply the power consumption side of the distribution network, achieving peak shaving and frequency regulation, and stable grid operation; or, the wind power conversion device initially... Finally, it connects to the high-voltage cable 4100. Under normal power generation conditions, the power output from the wind power conversion device is supplied to the power consumption side of the distribution network via the high-voltage cable. When the current power load is low and the wind power conversion device generates excess power, the excess power is first stored in the energy storage device 1000, reducing wind and solar curtailment rates and improving the problem of new energy power generation consumption. Furthermore, when the power load is high, the grid issues an instruction to transmit the power stored in the energy storage device 1000, along with the high-voltage cable 4100, in a grid-connected mode to supply power to the power consumption side. This provides various services for grid operation, including peak shaving, frequency regulation, and backup, fully leveraging the grid's peak shaving function, promoting peak shaving and valley filling, and alleviating grid power supply pressure. It can be understood that the energy storage device 1000 in the energy storage system 4000 is used to supply power to electrical equipment.

[0030] In some embodiments on the distribution network side, the first power conversion device 4200 can be a photovoltaic power conversion device. The energy storage device 1000 is connected to the high-voltage cable 4100 and installed downstream of the high-voltage cable 4100 and between the user load. The power output of the photovoltaic power conversion device is stored in the energy storage device 1000, which can respond in a timely manner to act as a backup power source when the power grid / distribution network fails. Alternatively, it can provide power supply support to alleviate line congestion when the high-voltage cable 4100 transmission line is blocked, and to delay the economic pressure caused by the expansion of the power grid / distribution capacity when the power grid is planned to be expanded.

[0031] Optionally, the first power conversion device 4200 may include, but is not limited to, a wind power conversion device, and the second power conversion device 4300 may include, but is not limited to, a photovoltaic power conversion device. The first power conversion device 4200 and the second power conversion device 4300 can convert at least one of solar energy, light energy, wind energy, thermal energy, tidal energy, biomass energy and mechanical energy into electrical energy.

[0032] Optionally, the energy storage device 1000 may include, but is not limited to, energy storage applications such as energy storage power stations, hydropower / thermal / wind power generation systems, solar power generation systems, mobile power systems, smart home systems, or temporary power supply systems, and may also be applied in multiple fields such as data centers, military equipment, aerospace, charging piles, and electric vehicles.

[0033] Please see Figure 2 and Figure 3 , Figure 2 for Figure 1 The diagram shown is a structural schematic of an energy storage device in an energy storage system. Figure 3 for Figure 2 The diagram shows the exploded structure of the energy storage device.

[0034] This application provides an energy storage device 1000. The energy storage device 1000 may include, but is not limited to, single-cell batteries, or battery modules, battery packs, battery clusters, power banks, energy storage cabinets / containers, and other battery integrated systems composed of single-cell batteries. Optionally, the single-cell battery can be a rechargeable battery, which refers to a battery cell that can be reactivated by charging after discharge and continue to be used. The single-cell battery can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this application does not specifically limit this. The actual application form of the energy storage device 1000 provided in this application embodiment can be, but is not limited to, the listed products, and can also be other application forms. This application embodiment does not strictly limit the application form of the energy storage device 1000. This application embodiment only uses a square single-cell battery as an example for illustration. In some embodiments, when the energy storage device 1000 is a single battery cell, the energy storage device 1000 may also be a battery of other shapes besides a square battery, such as a cylindrical battery, a prismatic battery, etc.

[0035] For ease of description, the width direction of the energy storage device 1000 is defined as the X-axis, the length direction as the Y-axis, and the height direction as the Z-axis. The X-axis, Y-axis, and Z-axis are all perpendicular to each other.

[0036] The directional terms such as "upper," "lower," "bottom," "top," "right," and "left" mentioned in the embodiments of this application are based on the appendix to the specification. Figure 2 The description is based on the orientation shown. It does not constitute a limitation on the actual application scenario of the energy storage device 1000. Specifically, the positive direction toward the Z-axis is defined as the top or top of the energy storage device 1000, and the negative direction toward the Z-axis is defined as the bottom or bottom of the energy storage device 1000.

[0037] like Figure 2As shown, the energy storage device 1000 includes a housing 200, an end cap assembly 100, a battery cell 300, and an insulating film (not shown). The housing 200 has an opening 201 and a receiving cavity 202. The receiving cavity 202 communicates with the opening 201 and contains an electrolyte. The battery cell 300 is housed within the receiving cavity 202 and can be immersed in the electrolyte. The end cap assembly 100 is mounted on one side of the battery cell 300 in the height direction (i.e., the Z-axis direction) and seals the opening 201 of the housing 200 to isolate the internal and external environments of the energy storage device 1000. The insulating film is located between the housing 200 and the battery cell 300 and covers the bottom and peripheral surfaces of the battery cell 300 to separate and insulate the battery cell 300 from the housing 200. The insulating film is thermally fused to the end cap assembly 100 to prevent displacement of the insulating film relative to the battery cell 300, which would cause the insulating film to lose its insulating properties. In this embodiment, the housing 200 is a square aluminum shell, and the insulating film is a Mylar film.

[0038] Please refer to the following: Figure 4 , Figure 5 and Figure 6 , Figure 4 for Figure 3 The diagram shows the axial side structure of the end cap assembly of the energy storage device. Figure 5 for Figure 3 The diagram shown is an exploded view of the end cap assembly. Figure 6 for Figure 4 The diagram shows an exploded view of the end cap assembly of the energy storage device.

[0039] The end cap assembly 100 includes an end cap 10, a lower plastic 20, a bracket assembly 30, an explosion-proof valve 40, a protective plate 50, a terminal post 60, a pressure block 70, a connecting piece 80, an upper plastic 91, and a sealing ring 92. The lower plastic 20 and the end cap 10 are stacked together along the thickness direction of the end cap assembly 100. The explosion-proof valve 40 and the protective plate 50 are both mounted on the end cap 10. The bracket assembly 30 is mounted on the side of the lower plastic 20 facing away from the end cap 10 to abut against the battery cell 300, and the bracket assembly 30 is connected to the end cap 10 and the lower plastic 20. The upper plastic 91 is mounted on the side of the end cap 10 facing away from the lower plastic 20. The pressure block 70 and the connecting piece 80 are both mounted on the side of the lower plastic 20 facing away from the end cap 10, and the connecting piece 80 is farther from the end cap 10 than the pressure block 70. Along the thickness direction of the end cap assembly 100, the pole post 60 is sequentially inserted through the upper plastic 91, the end cap 10, the lower plastic 20, and the pressure block 70, and is welded to the connecting piece 80. The sealing ring 92 is sleeved on the pole post 60 and clamped between the pressure block 70, the end cap 10, the lower plastic 20, and the upper plastic 91 to seal the gap between the pressure block 70, the end cap 10, the lower plastic 20, the upper plastic 91, and the pole post 60.

[0040] Among them, such as Figure 5 and Figure 6As shown, there are two of each of the following: terminal post 60, pressure block 70, connecting piece 80, upper plastic 91, and sealing ring 92. The two terminal posts 60 are located at opposite ends along the length of the end cap assembly 100; one serves as the positive terminal post, and the other as the negative terminal post. One of the pressure blocks 70 serves as the positive pressure block, and the other as the negative pressure block. One of the connecting pieces 80 serves as the positive connecting piece, and the other as the negative connecting piece. One of the upper plastic 91 is the positive upper plastic, and the other as the negative upper plastic. One of the two sealing rings 92 is the positive sealing ring, and the other as the negative sealing ring.

[0041] The positive electrode post is sequentially inserted through the upper plastic, end cap 10, lower plastic 20, and positive electrode pressure block, and is welded to the positive electrode connecting piece. The positive electrode sealing ring is fitted onto the positive electrode post and seals the gap between the lower plastic 20, end cap 10, upper plastic, positive electrode post, and positive electrode pressure block. The negative electrode post is sequentially inserted through the upper plastic, end cap 10, lower plastic 20, and negative electrode pressure block, and is welded to the negative electrode connecting piece 80. The negative electrode sealing ring is fitted onto the negative electrode post and seals the gap between the lower plastic 20, end cap 10, upper plastic, negative electrode post, and negative electrode pressure block.

[0042] The bracket assembly 30 includes an explosion-proof bracket 31 and two support frames 32. The two support frames 32 are respectively mounted at both ends of the lower plastic 20 along its length (i.e., the Y-axis direction). Along the Y-axis direction, the explosion-proof bracket 31 is located between the two support frames 32 and spaced apart from them. In this embodiment, both the explosion-proof bracket 31 and the two support frames 32 are elongated metal parts with good structural strength and rigidity. In some embodiments, the explosion-proof bracket 31 and / or the support frames 32 can be made of other materials with a melting point higher than that of the lower plastic 20 and high structural strength. Moreover, the number and type of brackets included in the bracket assembly 30 are not limited to the three specified in this embodiment and can be set according to actual product requirements. This application does not impose any limitations in this regard.

[0043] It should be noted that when the bracket in the bracket assembly 30 is made of conductive materials such as metal, its outer surface needs to be provided with insulating material, such as high-temperature resistant tape, to prevent the battery cell 300 from short-circuiting through the bracket and end cap 10.

[0044] Please see Figure 5 , Figure 6 and Figure 7 , Figure 7 for Figure 6 The diagram shows the structural diagram of the end cap of the end cap assembly.

[0045] The end cap 10 includes a top surface 11 and a bottom surface 12. The top surface 11 and the bottom surface 12 are arranged facing away from each other along the thickness direction (i.e., the Z-axis direction) of the end cap 10. In this embodiment, the end cap 10 is a rectangular sheet of light aluminum.

[0046] The end cap 10 also includes two mounting grooves 13. Both mounting grooves 13 are recessed into the bottom surface 12 of the end cap 10 and recessed towards the top surface 11. The two mounting grooves 13 are located at opposite ends along the length direction (i.e., the Y-axis direction) of the end cap 10. The two mounting grooves 13 are used for mating and positioning with the lower plastic 20.

[0047] The end cap 10 also includes two first electrode through holes 14. Each first electrode through hole 14 penetrates the top surface 11 of the end cap 10 and the bottom wall of an assembly groove 13 (not shown). One first electrode through hole 14 is used for the positive electrode to pass through, and the other first electrode through hole 14 is used for the negative electrode to pass through.

[0048] The end cap 10 also includes an injection hole 15 and an explosion-proof hole 16. Both the injection hole 15 and the explosion-proof hole 16 penetrate the top surface 11 and bottom surface 12 of the end cap 10. Both the injection hole 15 and the explosion-proof hole 16 are located between two first pole post through holes 14, with the injection hole 15 located between the explosion-proof hole 16 and one first pole post through hole 14. The injection hole 15, the explosion-proof hole 16, and the two assembly slots 13 are spaced apart from each other. The injection hole 15 is used to inject electrolyte into the energy storage device 1000. The explosion-proof hole 16 is used to accommodate the explosion-proof valve 40 and the protective plate 50, and to allow gas generated inside the energy storage device 1000 to escape. The explosion-proof hole 16, the explosion-proof valve 40, and the protective plate 50 can be understood as an explosion-proof structure.

[0049] The end cap 10 also includes multiple limiting grooves 17. Each limiting groove 17 is recessed into the bottom surface 12 of the end cap 10 and recessed towards the top surface 11. Each limiting groove 17 is adjacent to and spaced apart from the periphery of the explosion-proof hole 16. Each limiting groove 17 is used to engage with the lower plastic 20 for positioning. In this embodiment, there are four limiting grooves 17.

[0050] The end cap 10 also includes an insulating layer (not shown). The insulating layer covers the bottom surface 12 of the end cap 10 to insulate the cell 300 from the end cap 10. In this embodiment, the insulating layer completely covers the bottom surface 12 of the end cap 10. In some embodiments, the insulating layer covers the area on the bottom surface 12 of the end cap 10 not covered by the lower plastic 20. This application is not limited to this.

[0051] The insulating layer can be formed by performing an oxidation treatment on the bottom surface 12 of the end cap 10, or by attaching an insulating film to the bottom surface 12 of the end cap 10. Among them, the oxidation treatment can be achieved by, but not limited to, spraying insulating materials, anodic oxidation, etc. The material of the insulating film can be, but not limited to, polypropylene (PP), polyethylene terephthalate (PET), polyimide (PI), etc.

[0052] Please refer to Figure 8 and Figure 9 , Figure 8 which Figure 5 is a schematic structural diagram of the lower plastic of the end cap assembly shown, Figure 9 and Figure 6 is a schematic structural diagram of the lower plastic of the end cap assembly shown.

[0053] The lower plastic 20 includes a main body H and a hot-melt edge r. The main body H includes an upper surface a and a lower surface b. Along the thickness direction of the main body H (i.e., the Z-axis direction), the upper surface a and the lower surface b are arranged facing away from each other. The main body H is provided with a through hole K that penetrates through the upper surface a and the lower surface b of the main body H for the explosion-proof bracket 31 and the support bracket 32 to pass through. The hot-melt edge r protrudes from the upper surface a of the main body H and is provided at the edge of the upper surface a. The hot-melt edge r is used for thermally connecting with the insulating film. The number of the hot-melt edges r is at least two.

[0054] In this embodiment, as Figure 8 and Figure 9 shown, the lower plastic 20 includes a first lower plastic 21 and two second lower plastics 22. Along the length direction of the lower plastic 20 (i.e., the Y-axis direction), the first lower plastic 21 is located between the two second lower plastics 22 and is spaced apart from the two second lower plastics 22. It can be understood that the lower plastic 20 in this embodiment has a three-section structure. The first lower plastic 21 and the second lower plastics 22 are both made of plastic and are used for insulation. The plastic material is such as PP, etc.

[0055] The first lower plastic 21 includes a first main body H1. The first main body H1 includes a first upper surface a1 and a first lower surface b1. The first upper surface a1 and the first lower surface b1 are arranged facing away from each other along the thickness direction of the first main body H1 (i.e., the Z-axis direction). The first main body H1 includes a first main body part H11 and a first protruding part H12. The first protruding part H12 protrudes from one side of the first main body part H11 in the width direction (i.e., the Y-axis direction). It can be understood that the first main body H1 is generally a "convex"-shaped plate body.

[0056] The first protruding portion H12 is used to cover the injection hole 15 of the end cap 10. The first lower surface b1 of the first protruding portion H12 is provided with a liquid distribution part 211, and the first protruding portion H12 is provided with a liquid distribution hole 212. The liquid distribution hole 212 is used to communicate with the injection hole 15, and the liquid distribution part 211 is also connected to the liquid distribution hole 212. This allows the electrolyte injected from the injection hole 15 to flow into the energy storage device 1000 through the liquid distribution hole 212 and the liquid distribution part 211 in sequence. The liquid distribution part 211 is used to prevent the electrolyte injected from the injection hole 15 from directly impacting the battery cell 300, and also to prevent the internal electrolyte from splashing during the transportation of the energy storage device 1000.

[0057] The first lower plastic part 21 also includes a connecting hole 213 and two first through holes 214. The connecting hole 213 and the two first through holes 214 both penetrate the first upper surface a1 and the first lower surface b1 of the first main body portion H11. Along the length direction of the first main body portion H11 (i.e., the X-axis direction), the connecting hole 213 is located between the two first through holes 214 and is spaced apart from them. The connecting hole 213 is used to be positioned opposite to the explosion-proof hole 16 of the end cap 10. The first through holes 214 are used for the explosion-proof bracket 31 to pass through.

[0058] The first lower plastic part 21 also includes a plurality of first limiting posts 215. Each of the first limiting posts 215 protrudes from the first upper surface a1 of the first main body part H11. There are two or more first limiting posts 215. Each first limiting post 215 is accommodated within a limiting groove 17 of the end cap 10 to cooperate with and limit the end cap 10. In this embodiment, there are four first limiting posts 215, with every two first limiting posts 215 located on either side of a first through hole 214 along the Y-axis.

[0059] like Figure 9 As shown, the first lower plastic part 21 also includes a plurality of second limiting posts 216. Each of the plurality of second limiting posts 216 protrudes from the first lower surface b1 of the first main body portion H11. There are two or more second limiting posts 216. Each second limiting post 216 is used to cooperate with the explosion-proof bracket 31 for limiting movement. In this embodiment, there are two second limiting posts 216. Each second limiting post 216 is located between a first through hole 214 and a connecting hole 213.

[0060] The first lower plastic 21 also includes two first hot-melt edges r1. Both first hot-melt edges r1 protrude from the first lower surface b1 of the first main body portion H11, and are respectively located on both sides of the first lower surface b1 along the X-axis direction. Both first hot-melt edges r1 are used for hot-melt bonding with the insulating film.

[0061] In this embodiment, the structures of the two second lower plastics 22 are substantially the same. Among them, one second lower plastic 22 is used to insulate the positive electrode terminal from the end cap 10 and is the positive electrode lower plastic. The other second lower plastic 22 is used to insulate the negative electrode terminal from the end cap 10 and is the negative electrode lower plastic.

[0062] The second lower plastic 22 includes a second body H2. The second body H2 includes a second upper surface a2 and a second lower surface b2. The second upper surface a2 and the second lower surface b2 are arranged back to back along the thickness direction of the second body H2 (i.e., the Z-axis direction). The second body H2 includes a second main body part H21 and a second protruding part H22. The second protruding part H22 protrudes from one side of the second main body part H21 in the width direction (i.e., the Y-axis direction). It can be understood that the second body H2 is generally a "convex"-shaped plate body.

[0063] The second lower plastic 22 further includes a mounting groove 221. The mounting groove 221 is used to accommodate the pressing block 70. The mounting groove 221 is recessed in the second lower surface b2 of the second protruding part H22, and a limiting protrusion 222 is correspondingly formed on the second upper surface a2. That is, the second lower plastic 22 further includes a limiting protrusion 222, and the limiting protrusion 222 protrudes from the second upper surface a2 of the second protruding part H22. The limiting protrusion 222 includes a limiting surface 2221. The limiting surface 2221 has the same orientation as the second upper surface a2. Among them, the mounting groove 221 of one second lower plastic 22 is used to accommodate the positive electrode pressing block, and the other is used to accommodate the negative electrode pressing block. The limiting protrusions 222 of the two second lower plastics 22 are each used to be placed in an assembly groove 13 of the end cap 10.

[0064] The second lower plastic 22 further includes a second terminal through hole 223. The second terminal through hole 223 penetrates through the bottom wall of the mounting groove 221 and the limiting surface 2221 of the limiting protrusion 222. The second terminal through hole 223 is used for the terminal 60 to pass through. Among them, the second terminal through hole 223 of one second lower plastic 22 is used for the positive electrode terminal to pass through, and the second terminal through hole 223 of the other second lower plastic 22 is used for the negative electrode terminal to pass through.

[0065] The second lower plastic 22 also includes a second hot-melt edge r2 and two third hot-melt edges r3. The second hot-melt edge r2 and the two third hot-melt edges r3 all protrude from the second lower surface b2 of the second main body portion H21. Along the Y-axis, the second hot-melt edge r2 and the two third hot-melt edges r3 are all located on the side of the second main body portion H21 away from the second protruding portion H22. Along the X-axis, the second hot-melt edge r2 is located between the two third hot-melt edges r3 and is spaced apart from them. The second hot-melt edge r2 is a straight protruding edge, located in the middle of the edge of the second main body portion H21 on the side away from the second protruding portion H22 along the Y-axis. The two third hot-melt edges r3 are both bent protruding edges, and are respectively located at two corners of the second main body portion H21 away from the second protruding portion H22 along the Y-axis. It can be understood that, along the X-axis, the second hot-melt edge r2 and the two third hot-melt edges r3 are at least partially not on the same plane. The second hot-melt edge r2 and the two third hot-melt edges r3 are both used for hot-melt bonding with the insulating film. In some embodiments, the second hot-melt edge r2 and the two third hot-melt edges r3 can be made into continuous convex edges, that is, the hot-melt edges r on the second lower plastic 22 can be made into continuous convex edges. Alternatively, the number of hot-melt edges r on the second lower plastic 22 is not limited to three, and may include other hot-melt edges r besides the first hot-melt edge r1 and the two third hot-melt edges r3. This application does not impose any limitations on this.

[0066] The second lower plastic part 22 also includes two second perforations 224. Both second perforations 224 penetrate the second lower surface b2 and the second upper surface a2 of the second main body part H21, and are located at opposite ends of the length direction (i.e., the X-axis direction) of the second main body part H21. Each second perforation 224 is adjacent to and connected to a third hot-melt edge r3. Alternatively, each third hot-melt edge r3 and the second main body part H21 can be understood as forming a second perforation 224. The second perforations 224 are used for the support frame 32 to pass through.

[0067] The second lower plastic part 22 also includes a snap-fit ​​protrusion 225. The snap-fit ​​protrusion 225 protrudes from the second lower surface b2 of the second main body part H21 and is connected to a surface of the second hot-melt edge r2 facing the second pole post through hole 223. The snap-fit ​​protrusion 225 is used to cooperate with the support frame 32 for positioning.

[0068] Understandably, the lower plastic 20 is divided into three segments. The first body H1 of the first lower plastic 21 and the second bodies H2 of the two second lower plastics 22 constitute the body H of the lower plastic 20. The first upper surface a1 of the first body H1 and the second upper surface a2 of the second body H2 constitute the upper surface a of the lower plastic 20, and the first lower surface b1 and the second lower surface b2 constitute the lower surface b of the lower plastic 20. Along the Y-axis direction, the second protruding portions H22 of the two second lower plastics 22 extend towards the first lower plastic 21. There are eight hot-melt edges r, including two first hot-melt edges r1, two second hot-melt edges r2, and four third hot-melt edges r3. The two first hot-melt edges r1 are respectively located on both sides of the width direction (i.e., the X-axis direction) of the body H. The two second hot-melt edges r2 are respectively located at both ends of the length direction (i.e., the Y-axis direction) of the body H. Every two third hot-melt edges r3 are located at one end of the length direction of the body H, and each third hot-melt edge r3 is located at a corner of the body H. Along the Y-axis, each first hot melt edge r1 is located between two third hot melt edges r3 and is spaced apart from the two third hot melt edges r3.

[0069] In some embodiments, the lower plastic 20 can be a single, continuous sheet, or it can be a multi-segment structure, not limited to three segments. This application does not impose any limitations on this.

[0070] Please refer to the following: Figure 10 and Figure 11 , Figure 10 for Figure 5 The diagram shown is a structural schematic of the explosion-proof bracket of the end cap assembly bracket assembly. Figure 11 for Figure 6 The diagram shows the structure of the explosion-proof bracket of the end cap assembly bracket assembly. It should be noted that... Figure 10 and Figure 11 The dashed line in the middle indicates the connection boundary between the body segment, the first abutment segment, and the first assembly segment.

[0071] In this embodiment, the explosion-proof bracket 31 is used to connect with the first lower plastic 21.

[0072] The explosion-proof bracket 31 includes a first surface 311, a second surface 312, and two first side surfaces 313. The first surface 311 and the second surface 312 are arranged opposite to each other along the thickness direction (i.e., the Z-axis direction) of the explosion-proof bracket 31. The two first side surfaces 313 are arranged opposite to each other along the width direction (i.e., the Y-axis direction) of the explosion-proof bracket 31. Both first side surfaces 313 are connected to the first surface 311 and the second surface 312.

[0073] The explosion-proof bracket 31 also includes a first through groove 314 and a second through groove 319. The number of first through grooves 314 and second through grooves 319 can be one or more. In this embodiment, there are two first through grooves 314 and one second through groove 319. Along the length of the explosion-proof bracket 31, the second through groove 319 is located between the two first through grooves 314 and is spaced apart from them. The openings of the two first through grooves 314 in the thickness direction and the openings of the second through groove 319 in the thickness direction are positioned opposite to each other.

[0074] Both first through grooves 314 are recessed into the second surface 312 of the explosion-proof bracket 31, and both protrude from the first surface 311 to form first protrusions 315; that is, the first through grooves 314 are recessed from the second surface 312 towards the first surface 311, and the first protrusions 315 are formed on the first surface 311. Both first through grooves 314 penetrate the two first side surfaces 313 of the explosion-proof bracket 31 to allow gas to pass through. Along the length direction (i.e., the X-axis direction) of the explosion-proof bracket 31, the two first through grooves 314 are spaced apart from each other, meaning there are two first protrusions 315, spaced apart from each other. The first protrusions 315 are used to abut against the first lower plastic 21. A second through groove 319 is formed between the two first protrusions 315. The second through groove 319 penetrates the two first side surfaces 313 of the explosion-proof bracket 31 to allow gas to pass through.

[0075] The explosion-proof bracket 31 also includes a body section m, a first abutment section n, and a mounting section o. In this embodiment, the explosion-proof bracket 31 can be integrally formed, such as by stamping. Along the length of the explosion-proof bracket 31, the first abutment section n is located between the body section m and the mounting section o, connecting the body section m and the mounting section o. The mounting section o is located at the end of the explosion-proof bracket 31 along its length. The mounting section o is used to fix to the end cap 10 by means not limited to welding or riveting. The body section m is positioned opposite and spaced apart from the connecting hole 213 of the first lower plastic 21 to allow gas to enter the connecting hole 213. The first abutment section n abuts against the first lower plastic 21. Furthermore, both the body section m and the first abutment section n support the battery cell 300. In this embodiment, there are two mounting sections o and two first abutment sections n, and one body section m. The two mounting sections o are located on opposite sides of the body section m along the Y-axis, and each first abutment section n is connected to both the body section m and one mounting section o.

[0076] The first abutting section n includes a first abutting plate n1, two first plates n2, and a first support plate n3. The two first plates n2 protrude from opposite sides of the first abutting plate n1 along the X-axis, and both first plates n2 are angled to the first abutting plate n1. The first support plate n3 protrudes from the side of one of the first plates n2 away from the first abutting plate n1, and the first support plate n3 is angled to the first plate n2. The two first plates n2 and the first abutting plate n1 form a first through groove 314. One first plate n2 is connected to the body section m and is angled to the body section m. The other first plate n2 is connected to the first support plate n3. The first abutting plate n1 abuts against the first lower plastic 21. The first support plate n3 supports the battery cell 300.

[0077] The first abutment plate n1 includes a limiting hole 318. The limiting hole 318 extends through both surfaces of the first abutment plate n1 in the thickness direction. The limiting hole 318 is used to engage with the second limiting post 216 of the first lower plastic 21 for limiting.

[0078] The mounting section o includes an assembly plate o1 and a second plate o2. Along the X-axis, the second plate o2 protrudes from the side of the first support plate n3 away from the first abutment plate n1, and the assembly plate o1 protrudes from the side of the second plate o2 away from the first support plate n3. The second plate o2 is angled to both the first support plate n3 and the assembly plate o1. The assembly plate o1 is used to fix the end cap 10 by means of welding, riveting, or other methods. In this embodiment, the assembly plate o1 is welded to the end cap 10. The surface of the assembly plate o1 in the thickness direction is parallel to the bottom surface 12 of the end cap 10, ensuring that there are welding points between the assembly plate o1 and the end cap 10, thus ensuring the welding strength between the explosion-proof bracket 31 and the end cap 10.

[0079] In this embodiment, along the Z-axis, the body segment m and the first support plate n3 are flush, while the first abutment plate n1 and the assembly plate o1 are not flush, and the assembly plate o1 is further away from the first support plate n3 than the first abutment plate n1. That is, the explosion-proof bracket 31 has a multi-bending structure, which improves the structural strength and rigidity of the explosion-proof bracket 31, so as to support the battery cell 300 well and prevent the battery cell 300 from moving towards the end cover 10 in the event of thermal runaway.

[0080] The explosion-proof bracket 31 also includes a vent 316. The vent 316 penetrates the first surface 311 and the second surface 312 of the explosion-proof bracket 31, and is located on the body segment m. That is, the vent 316 penetrates both surfaces of the body segment m in the thickness direction (i.e., the Z-axis direction). The vent 316 is used to allow gas to pass through. In this embodiment, the second through groove 319 and the two first through grooves 314 constitute the first ventilation structure Q1 of the explosion-proof bracket 31. The ventilation direction of the first ventilation structure Q1 is consistent with the length direction of the end cap assembly 100. The vent 316 communicates with the first ventilation structure Q1, and the vent 316 is approximately a rectangular hole.

[0081] The explosion-proof bracket 31 also includes a guide plate 317. The guide plate 317 protrudes from the first surface 311 of the explosion-proof bracket 31 and is located on one edge of the vent hole 316 along the Y-axis direction. The guide plate 317 is located on the body segment m. That is, the guide plate 317 protrudes from one surface of the body segment m facing the first lower plastic 21. The guide plate 317 is set at an angle to the body segment m and is inclined inwards towards the vent hole 316. That is, along the Z-axis direction, the projection of the guide plate 317 lies within the projection of the vent hole 316. The guide plate 317 serves to guide the gas entering the vent hole 316.

[0082] Please refer to the following: Figure 12 and Figure 13 , Figure 12 for Figure 5 The diagram shows the structural design of the support frame of the end cap assembly bracket. Figure 13 for Figure 6 The diagram shows the structural design of the support frame of the end cap assembly bracket. It should be noted that... Figure 12 and Figure 13 The dashed lines in the diagram represent the boundaries between the first assembly section u, the second assembly section v, and the second abutment section w.

[0083] In this embodiment, the two support frames 32 have roughly the same structure. One support frame 32 is used to connect to the lower plastic of the positive electrode, and the other support frame 32 is used to connect to the lower plastic of the negative electrode.

[0084] The support frame 32 includes a third surface 321, a fourth surface 322, and two second side surfaces 323. The third surface 321 and the fourth surface 322 are arranged opposite to each other along the thickness direction (i.e., the Z-axis direction) of the support frame 32. The two second side surfaces 323 are arranged opposite to each other along the width direction (i.e., the Y-axis direction) of the support frame 32. Both second side surfaces 323 are connected to the third surface 321 and the fourth surface 322.

[0085] The support frame 32 also includes a third through groove 329, a fourth through groove 325, and a third recess 324. Both the fourth through groove 325 and the third recess 324 are recessed into the third surface 321 of the support frame 32. The fourth through groove 325 protrudes from the fourth surface 322 to form a second protrusion 326, and the fourth through groove 325 penetrates through the two second side surfaces 323 of the support frame 32 to allow gas passage. The third recess 324 protrudes from the fourth surface 322 to form a third protrusion 327. A third through groove 329 is formed between adjacent second protrusions 326 and third protrusions 327, and the third through groove 329 penetrates through the two second side surfaces 323 of the support frame 32 to allow gas passage. The number of third through grooves 329, fourth through grooves 325, and third recesses 324 can be one or more. In this embodiment, along the length direction (i.e., the X-axis direction) of the support frame 32, there are four third through slots 329, two fourth through slots 325 and two second protrusions 326, and three third grooves 324 and three protrusions 327. One fourth through slot 325 and two third through slots 329 are provided between every two third grooves 324. A third through slot 329 is provided between each fourth through slot 325 and one third groove 324. The third through slots 329, fourth through slots 325, and third grooves 324 are spaced apart along the length direction of the support frame 32. The opening of the fourth through slot 325 in the thickness direction faces away from the opening of the third through slot 329 in the thickness direction, and faces the same direction as the opening of the third groove 324 in the thickness direction. Both the second protrusion 326 and the third protrusion 327 are used to abut against the battery cell. The third protrusion 327 and the second protrusion 326 are alternately spaced along the length direction of the support frame 32. A third through groove 329 is formed between each third protrusion 327 and a second protrusion 326. In this embodiment, a plurality of fourth through grooves 325 and a plurality of third through grooves 329 constitute the second ventilation structure Q2 of the support frame 32, and the ventilation direction of the second ventilation structure Q2 is consistent with the length direction of the end cap assembly 100.

[0086] The support frame 32 also includes multiple assembly sections and multiple second abutment sections w. In this embodiment, there are three assembly sections and two second abutment sections w. A second abutment section w connects every two assembly sections. The support frame 32 is integrally formed, such as by stamping. For ease of description, each assembly section includes a first assembly section u and a second assembly section v. Along the length of the support frame 32, the second abutment section w is located between the first assembly section u and the second assembly section v, connecting them. The second assembly section v is located at the end of the support frame 32 along its length. The second assembly section v is used to fix to the end cap 10 by means not limited to welding or riveting. The first assembly section u is used to snap onto the second lower plastic 22. The second abutment section w is used to abut against the second lower plastic 22. Furthermore, the first assembly section u, the second assembly section v, and the second abutment section w all support the battery cell 300. In this embodiment, there are two second assembly sections v and two second abutment sections w, and one first assembly section u. Two second assembly sections v are located on both sides of the first assembly section u along the X-axis, and each second abutment section w is connected to the first assembly section u and a second assembly section v.

[0087] The first assembly section u includes a second support plate u1, two first side plates u2, and two snap-fit ​​plates u3. The two snap-fit ​​plates u3 protrude from opposite sides of the second support plate u1 along the Y-axis. The two first side plates u2 protrude from opposite sides of the second support plate u1 along the X-axis. The two first side plates u2 and the two snap-fit ​​plates u3 are all angled to the second support plate u1, and together with the second support plate u1, they form a third groove 324. Each of the two first side plates u2 is connected to a second abutment section w. The second support plate u1 supports the battery cell 300. One of the two snap-fit ​​plates u3 engages with and limits the snap-fit ​​protrusion 225 of the second lower plastic 22.

[0088] Each snap-fit ​​plate u3 includes a first abutment surface u31. The orientation of the first abutment surface u31 is the same as the orientation of the bottom wall of the third groove 324. Each snap-fit ​​plate u3 also includes a snap-fit ​​groove u32. The snap-fit ​​groove u32 is recessed in the first abutment surface u31 and extends through both surfaces of the snap-fit ​​plate u3 in the thickness direction. The snap-fit ​​groove u32 is used to engage and limit the snap-fit ​​protrusion 225 of the second lower plastic 22. In this embodiment, both snap-fit ​​plates u3 have snap-fit ​​grooves u32, ensuring the structural symmetry of the support frame 32. Even if the support frame 32 and the second lower plastic 22 are installed in reverse, the other snap-fit ​​plate u3 can still engage and limit the snap-fit ​​protrusion 225 of the second lower plastic 22, improving assembly efficiency.

[0089] The second assembly section v includes a support plate v1, a third side plate v2, and three upright plates v3. The third side plate v2 and one upright plate v3 protrude from opposite sides of the support plate v1 along the X-axis. The other two upright plates v3 protrude from opposite sides of the support plate v1 along the Y-axis. The third side plate v2 and the three upright plates v3 are spaced apart at the edge of the support plate v1. The third side plate v2 and the three upright plates v3 are all angled with the support plate v1, and together with the support plate v1, they form a third groove 324. The third side plate v2 is connected to the second abutment section w. The support plate v1 supports the battery cell 300. The three upright plates v3 are all used to fix the end cap 10 by means not limited to welding, riveting, etc. In some embodiments, the number of upright plates v3 can be one or two. This application does not limit the number of upright plates v3, as long as the connection strength between the second assembly section v and the end cap 10 is ensured.

[0090] The second abutment section w includes a third support plate w1, two fourth side plates w2, and two second abutment plates w3. The two fourth side plates w2 protrude from opposite sides of the third support plate w1 along the X-axis. Each second abutment plate w3 protrudes from the side of one fourth side plate w2 facing away from the third support plate w1. That is, the two second abutment plates w3 are located on opposite sides of the third support plate w1 along the X-axis, and each fourth side plate w2 is connected to both the third support plate w1 and the fourth side plate w2, forming an angle with both. The two fourth side plates w2 and the third support plate w1 together form a fourth through groove 325. One second abutment plate w3 is connected to a first side plate u2 of the first assembly section u, forming an angle with the first side plate u2, and the first side plate u2, the second abutment plate w3, and the fourth side plate w2 adjacent to the second abutment plate w3 together form a third through groove 329. Another second abutment plate w3 is connected to the third side plate v2 of the second assembly section v, and is set at an angle to the third side plate v2. The third side plate v2, the second abutment plate w3, and a fourth side plate w2 adjacent to the second abutment plate w3 together form a third through groove 329. The fourth through groove 325 is located between the two third through grooves 329 along the length of the support frame 32. The third support plate w1 is used to support the battery cell 300. Furthermore, both second abutment plates w3 are used to abut against the second lower plastic 22.

[0091] In this embodiment, along the Z-axis, the second support plate u1, multiple bearing plates v1, and multiple third support plates w1 are all flush, and multiple second abutment plates w3 are all flush. However, the second support plate u1, bearing plate v1, third support plate w1, and second abutment plate w3 are not flush. That is, the support frame 32 has multiple bends, and the support frame 32 is provided with multiple upright plates v3, so that the support frame 32 has good structural strength and rigidity to support the battery cell 300 well and prevent the battery cell 300 from moving towards the end cover 10 in the event of thermal runaway.

[0092] In some embodiments, the support frame 32 further includes a plurality of flow guide holes 328. Each third groove 324 and each fourth through groove 325 has a flow guide hole 328. The flow guide hole 328 in the third groove 324 extends through both sides of the third groove 324 and the second protrusion 326 facing away from each other in the Z-axis direction, and communicates with the third groove 324. The flow guide hole 328 in the fourth through groove 325 extends through both sides of the fourth through groove 325 and the third protrusion 327 facing away from each other in the Z-axis direction, and communicates with the fourth through groove 325. That is, the second support plate u1, the bearing plate v1, and the third support plate w1 each have a corresponding flow guide hole 328. The flow guide holes 328 are used to allow the electrolyte flowing into the third groove 324 and the fourth through groove 325 to quickly flow back to the battery cell 300. The number of flow guide holes 328 can be one or more. For example, the number of flow guide holes 328 is five.

[0093] Please refer to the following: Figure 14 , Figure 15 and Figure 16 , Figure 14 for Figure 4 The diagram shows a partial structural schematic of the end cap assembly. Figure 15 for Figure 14 The diagram shows a partial cross-sectional view of the end cap assembly along line AA. Figure 16 for Figure 14 The diagram shows a partial structure of the end cap assembly along the BB line.

[0094] In this embodiment, the explosion-proof valve 40 and the protective plate 50 are installed inside the explosion-proof hole 16 of the end cover 10. When the battery cell 300 experiences thermal runaway and generates a large amount of gas, the gas breaks through the explosion-proof valve 40 and the protective plate 50 and is discharged, thereby achieving pressure relief and ensuring the safety of the energy storage device 1000.

[0095] The first lower plastic 21 and two second lower plastics 22 are both mounted on the end cap 10. The first body H1 and the second body H2 are stacked on the end cap 10, and the first upper surface a1 of the first body H1 and the second upper surface a2 of the second body H2 are both connected to the bottom surface 12 of the end cap 10. The four first limiting posts 215 of the first body H1 are each housed in a limiting groove 17 of the end cap 10 to limit and fix the first lower plastic 21 to the end cap 10, ensuring the accuracy of the subsequent installation position of the explosion-proof bracket 31. The connecting hole 213 of the first body H1 and the explosion-proof hole 16 of the end cap 10 are coaxially arranged and connected. Along the Z-axis direction, the projection of the explosion-proof hole 16 is completely located within the projection of the connecting hole 213, so as to ensure that the first body H1 will not obstruct the gas inside the energy storage device 1000 from being discharged from the explosion-proof hole 16. The liquid distribution section 211 of the first body H1 completely covers the liquid injection hole 15 of the end cap 10. The liquid distribution hole 212 and the liquid injection hole 15 are connected so that the electrolyte injected from the liquid injection hole 15 will not directly impact the battery cell 300, thus ensuring the performance of the battery cell 300. The two first through holes 214 of the first body H1 expose part of the bottom surface 12 of the end cap 10 for subsequent welding or riveting connection between the explosion-proof bracket 31 and the end cap 10.

[0096] The limiting protrusion 222 of the second body H2 is received within the assembly groove 13 of the end cap 10, and the limiting surface 2221 of the limiting protrusion 222 abuts against the bottom wall of the assembly groove 13. Along the Z-axis, the second pole post through hole 223 of the second body H2 is coaxially arranged and connected with the first pole post through hole 14 of the end cap 10, and the projection of the first pole post through hole 14 is completely located within the second pole post through hole 223. The two second through holes 224 of the second body H2 expose part of the bottom surface 12 of the end cap 10 for subsequent welding or riveting connection between the support frame 32 and the end cap 10.

[0097] The electrode post 60, sealing ring 92, upper plastic 91, and pressure block 70 are assembled together with the end cap 10 and lower plastic 20. The pressure block 70 is installed in the mounting groove 221 of the second lower plastic 22 and is limited by the mounting groove 221. The upper plastic 91 is installed on the side of the end cap 10 facing away from the second lower plastic 22 and passes through the first electrode post through hole 14 of the end cap 10. The pole post 60 is sequentially inserted through the upper plastic 91, the first pole post through hole 14 of the end cap 10, the second pole post through hole 223 of the second lower plastic 22, and the pressure block 70, and is welded and fixed to the pressure block 70. This allows the pole post 60 and the pressure block 70 to press against the sealing ring 92 and the second lower plastic 22. The sealing ring 92 seals the gap between the end cap 10, the pole post 60, the second lower plastic 22, the upper plastic 91, and the pressure block 70, and tightly presses the second lower plastic 22 onto the end cap 10, thereby limiting and fixing the second lower plastic 22 and the end cap 10 to ensure the accurate installation position of the subsequent support frame 32.

[0098] An explosion-proof bracket 31 is mounted on the first lower plastic section 21. Specifically, the explosion-proof bracket 31 is mounted on the side of the first main body portion H11 of the first lower plastic section 21 facing away from the end cap 10. The opening of the first through groove 314 in the thickness direction faces away from the first lower plastic section 21, and the first protrusion 315 formed by the first through groove 314 abuts against the first lower plastic section 21. The opening of the second through groove 319 in the thickness direction faces the first lower plastic section 21. That is, the main body section m and the first lower plastic section 21 are opposite to each other along the Z-axis and spaced apart to ensure that a sufficient channel is formed between the explosion-proof bracket 31 and the first lower plastic section 21 for gas to pass through, thereby improving the exhaust performance of the end cap assembly 100 and improving the safety performance of the energy storage device 1000.

[0099] The vent 316 of the main body section m is connected to the connecting hole 213 of the first lower plastic 21. The guide plate 317 is located in the gap between the main body section m and the explosion-proof valve 40, and is spaced apart from the explosion-proof valve 40 to direct the gas entering the vent 316 to the explosion-proof valve 40, avoiding gas interference from airflow and affecting exhaust efficiency. The first abutting section n abuts against the first lower plastic 21, and the first abutting plate n1 is connected to the first lower surface b1 of the first lower plastic 21. The two second limiting posts 216 of the first lower plastic 21 each pass through a limiting hole 318 of the first abutting plate n1 to achieve limiting and fixing of the explosion-proof bracket 31 and the first lower plastic 21. The mounting plate o1 of the mounting section o passes through the first through hole 214 of the first lower plastic 21 and is connected to the end cap 10 by welding or riveting.

[0100] Two support frames 32 are respectively mounted on two second lower plastic parts 22. Specifically, the support frame 32 is mounted on the side of the second main body H21 of the second lower plastic part 22 facing away from the end cover 10. The third through groove 329 of the support frame 32 faces away from the second lower plastic part 22 in the thickness direction, while the fourth through groove 325 and the third groove 324 face the second lower plastic part 22 in the thickness direction. The second protrusion 326 formed by the fourth through groove 325 and the third protrusion 327 formed by the third groove 324 are used to abut against the battery cell 300. The second support plate u1 and a plurality of third support plates w1 are arranged opposite to and spaced apart from the second lower plastic part 22 along the Z-axis direction. A plurality of first abutment plates n1 abut against the second lower plastic part 22. A snap-fit ​​plate u3 of the first assembly section u is disposed adjacent to the second hot-melt edge r2, and the snap-fit ​​groove u32 of the snap-fit ​​plate u3 is snapped and fixed with the snap-fit ​​protrusion 225 to assemble and fix the support frame 32 and the second lower plastic 22. Multiple bearing plates v1 and end caps 10 are arranged opposite to each other and spaced apart along the Z-axis. Multiple upright plates v3 pass through the second through hole 224 of the second lower plastic 22 and are connected to the end caps 10 by welding or riveting.

[0101] The third channel 329 and the fourth channel 325 work together to allow gas generated from both sides of the battery cell 300 along its length to flow through the third channel 329 and the fourth channel 325 of the support frame 32 to the first channel 314, the second channel 319, and the vent 316 of the explosion-proof bracket 31 in the event of thermal runaway in the energy storage device 1000. It can be understood that the ventilation directions of the first ventilator Q1 of the explosion-proof bracket 31 and the second ventilator Q2 of the support frame 32 are parallel to the length of the end cap assembly 100. The cooperation of the first ventilator Q1 of the explosion-proof bracket 31 and the second ventilator Q2 of the support frame 32 facilitates the smooth flow of gas generated from both sides of the battery cell 300 along its length to the explosion-proof structure of the end cap 10 for venting and depressurization, improving the venting performance of the end cap assembly 100 and enhancing the safety performance of the energy storage device 1000.

[0102] In some embodiments, the second lower plastic 22 and the end cap 10 can also be fixed together by means of a limiting post, and / or the second lower plastic 22 and the support frame 32 can also be fixed together by means of a limiting post. This application does not limit this.

[0103] Please refer to the following: Figure 2 , Figure 3 and Figure 4 .

[0104] like Figure 3 and Figure 4 As shown, each connecting piece 80 is located between a first lower plastic 21 and a second lower plastic 22, and is welded to a pole post 60 for conduction.

[0105] like Figure 2 As shown, the end cap assembly 100 is mounted on the battery cell 300. The electrode tabs and connecting pieces 80 of the battery cell 300 are welded together to achieve conductivity between the electrode post 60 and the battery cell 300. The first support plate n3 of the explosion-proof bracket 31 and the second support plate u1, bearing plate v1, and third support plate w1 of the support frame 32 all abut against the battery cell 300, so that an exhaust channel is formed between the end cap 10 and the lower plastic 20 and the battery cell 300. In this embodiment, the explosion-proof bracket 31 and the support frame 32 are supported between the battery cell 300, the end cap 10, and the lower plastic 20. When the battery cell 300 experiences thermal runaway and generates a large amount of high-temperature gas, the explosion-proof bracket 31 and the support frame 32 prevent the battery cell 300 from floating upwards towards the end cap assembly 100 and blocking the exhaust channel, thereby avoiding the problem of energy storage device explosion or shell 200 cracking caused by gas accumulation. Moreover, even if the lower plastic 20 melts, deforms, or even ignites at high temperature, the explosion-proof bracket 31 and the support frame 32 can still support and limit the battery cell 300, preventing the electrode tab of the battery cell 300 from colliding with the end cap 10 and causing a short circuit, thus improving the safety of the energy storage device 1000.

[0106] An insulating film covers the periphery and bottom surface of the battery cell 300 and is housed together with the battery cell 300 within the housing 200. The insulating film is fixed to the lower plastic 20 by multiple first hot-melt edges r1, multiple second hot-melt edges r2, and multiple third hot-melt edges r3, thus securing the insulating film to the end cap assembly 100. This prevents the insulating film from falling off or misaligning with the battery cell 300, and avoids the battery cell 300 being exposed and coming into contact with the housing 200, which could cause a short circuit.

[0107] In related technologies, when existing batteries experience thermal runaway, a large amount of high-temperature gas is generated inside the battery. During the process of the high-temperature gas being discharged from the battery, it can cause the lower insulation to melt, deform, or even ignite, resulting in the failure of the supporting function of the core. At the same time, the high-temperature gas pushes the core inside the battery upward towards the lower insulation, blocking the exhaust channel. This makes it difficult for a large amount of gas inside the battery to be discharged in time, which can lead to problems such as the battery cracking or even the battery itself, posing a great safety hazard.

[0108] In this embodiment, by providing a support assembly 30, such as an explosion-proof bracket 31 and two support frames 32, on the side of the lower plastic 20 facing away from the end cap 10, the lower plastic 20 will melt when the energy storage device 1000 experiences thermal runaway. The explosion-proof bracket 31 and the two support frames 32 can support the battery cell 300, preventing the battery cell 300 from moving towards the end cap assembly 100 along the height direction of the energy storage device 1000, thus avoiding the battery cell 300 from blocking the exhaust channel, thereby improving the exhaust performance of the end cap assembly 100 and the safety of the energy storage device 1000. Furthermore, both the explosion-proof bracket 31 and the support frame 32 are multi-bending structures. The first through groove 314 and the second through groove 319 of the explosion-proof bracket 31 form a first ventilation structure Q1, and the first through groove 314 and the second through groove 319 penetrate both sides of the explosion-proof bracket 31 in the width direction. At the same time, the third through groove 329 and the fourth through groove 325 of the support frame 32 form a second ventilation structure Q2, and the third through groove 329 and the fourth through groove 325 penetrate both sides of the support frame 32 in the width direction. This allows the gas generated from the side of the housing 200 and the battery cell 300 to flow from the first ventilation structure Q1 of the support frame 32 and the second ventilation structure Q2 of the explosion-proof bracket 31 to the explosion-proof structure of the end cover 10, ensuring the exhaust efficiency of the end cover assembly 100. Even if the energy storage device 1000 experiences thermal runaway and the lower plastic 20 fails, the bracket assembly 30 can still ensure that the end cover assembly 100 has sufficient exhaust channels to exhaust gas, thereby improving the safety performance of the energy storage device 1000.

[0109] Furthermore, the lower plastic 20 of this application is interrupted into multiple segments, which not only saves material of the lower plastic 20, thereby reducing the risk that the lower plastic 20 will melt or even ignite in the event of thermal runaway of the battery cell 300, but also reduces the weight and volume of the lower plastic 20, achieving lightweighting of the lower plastic 20, which in turn helps to achieve lightweighting of the energy storage device 1000.

[0110] In this embodiment, considering that the area of ​​the lower plastic 20 covering the end cap 10 is greatly reduced, an insulating layer is provided on the surface of the end cap 10 facing the lower plastic 20 to play the role of double insulation, so as to avoid the connecting piece 80 or the electrode of the cell 300 from easily overlapping with the end cap 10 and causing a short circuit.

[0111] The above are merely some embodiments and implementation methods of this application. The scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An end cap assembly for use in an energy storage device, characterized by, The end cover assembly comprises: an end cover; a lower plastic, comprising a first lower plastic and two second lower plastics; an explosion-proof support and two support supports, the explosion-proof support is provided with a first ventilation structure, the two support supports are each provided with a second ventilation structure, along the thickness direction of the end cover assembly, the first lower plastic and the two second lower plastics are each arranged on one surface of the end cover and connected in layers with the end cover, the two second lower plastics are located at two ends of the end cover in the length direction, and the first lower plastic is located between the two second lower plastics and arranged in a spaced manner with the two second lower plastics, the explosion-proof support is arranged on the side of the first lower plastic away from the end cover and penetrates the first lower plastic and the end cover, and the two support supports are each arranged on the side of the two second lower plastics away from the end cover and penetrates the two second lower plastics and the end cover; the ventilation directions of the first ventilation structure and the second ventilation structure are parallel to the length direction of the end cover assembly; the explosion-proof support and the support support are each used to abut against the cell of the energy storage device, wherein the melting points of the explosion-proof support and the support support are each greater than the melting point of the lower plastic.

2. The end cap assembly of claim 1, wherein, The explosion-proof support comprises a body segment, two first abutting segments and two mounting segments, along the width direction of the end cover assembly, the two first abutting segments are respectively connected to the two sides of the body segment, and each mounting segment is connected to the side of each first abutting segment away from the body segment, and each first abutting segment is arranged at an angle with the body segment and one mounting segment, respectively, the two mounting segments penetrate the first lower plastic and are connected with the end cover, and the two first abutting segments are limited by the first lower plastic; the two first abutting segments and the body segment are each used to abut against the cell; each first abutting segment has a first through slot, and the two first abutting segments and the body segment surround a second through slot, the second through slot is located between the two first through slots, the slot openings of the two first through slots in the thickness direction are arranged away from the slot opening of the second through slot in the thickness direction, the two first through slots and the second through slot each include a slot opening in the width direction of the first abutting segment, and the first ventilation structure comprises the two first through slots and the second through slot.

3. The end cap assembly of claim 1, wherein, One side of the second lower plastic away from the end cover is provided with a clamping protrusion; the support support comprises a plurality of assembly segments, the plurality of assembly segments comprise a first assembly segment and two second assembly segments, along the length direction of the assembly segment, the first assembly segment is located between the two second assembly segments, and the first assembly segment and the two second assembly segments are arranged in a spaced manner; the first assembly segment is provided with a clamping plate located on one side of the assembly segment in the width direction, the clamping plate is clamped with the clamping protrusion, the second assembly segment penetrates the second lower plastic and is connected with the end cover; the first assembly segment and the second assembly segment are each used to abut against the cell.

4. The end cap assembly of claim 3, wherein, The second assembly section comprises a bearing plate and a vertical plate, the vertical plate and the bearing plate are connected and arranged at the edge of the bearing plate, the bearing plate is opposite to the end cover and spaced apart along the thickness direction of the end cover assembly, and the vertical plate is connected to the end cover.

5. The end cap assembly of claim 3, wherein, The support frame further comprises two second abutting sections, one of the second abutting sections is connected between the first assembly section and each of the second assembly sections along the length direction of the support frame; and the second abutting section abuts the second lower plastic and is used for abutting the battery cell. Each of the second abutting sections is formed with two third through-slots and a fourth through-slot; the fourth through-slot is located between the two third through-slots, the openings of the two third through-slots in the thickness direction are opposite to the opening of the fourth through-slot in the thickness direction, the two third through-slots and the fourth through-slot each comprise an opening in the width direction of the second abutting section, and the second ventilation structure comprises the two third through-slots and the fourth through-slot.

6. The end cap assembly of claim 5, wherein, The support frame further comprises a flow guide hole, the flow guide hole penetrates through two surfaces in the thickness direction of the support frame.

7. The end cap assembly of claim 2, wherein, The end cover comprises an explosion-proof hole, the explosion-proof hole penetrates through two surfaces in the thickness direction of the end cover. The first lower plastic comprises a communication hole, the communication hole penetrates through two sides in the thickness direction of the first lower plastic, the first lower plastic is arranged opposite to the explosion-proof hole of the end cover in the thickness direction of the end cover assembly, and the communication hole and the explosion-proof hole are opposite and in communication. The body section comprises a ventilation hole, the body section is opposite to the first lower plastic and spaced apart in the thickness direction of the end cover assembly, and the ventilation hole is opposite to and in communication with the communication hole.

8. The end cap assembly of any one of claims 1-7, wherein, The surface of the end cover facing the lower plastic is concavely provided with a limiting groove, the surface of the first lower plastic facing the end cover is convexly provided with a first limiting column, and the first limiting column is accommodated in the limiting groove. The surface of the first lower plastic away from the end cover is convexly provided with a second limiting column, the explosion-proof support comprises a limiting hole, the limiting hole penetrates through two surfaces in the thickness direction of the explosion-proof support, and the second limiting column is accommodated in the limiting hole.

9. The end cap assembly of any one of claims 1-7, wherein, The end cover further comprises a liquid injection hole, the liquid injection hole penetrates through two surfaces in the thickness direction of the end cover, and along the length direction of the end cover assembly, the liquid injection hole is located on one side of the explosion-proof hole and spaced apart from the explosion-proof hole. The side surface of the first lower plastic away from the end cover is convexly provided with a liquid distribution part, and the first lower plastic is provided with a liquid distribution hole, the liquid distribution part and the liquid distribution hole are in communication, the liquid distribution part covers the liquid injection hole, and the liquid injection hole and the liquid distribution hole are in communication.

10. The end cap assembly of any one of claims 1-7, wherein, The end cover further comprises an insulating layer, the insulating layer covers the surface of the end cover facing the lower plastic, the explosion-proof support and the support frame are made of metal material, and the outer surfaces of the explosion-proof support and the support frame are completely covered with an insulating material.

11. An energy storage device, characterized by, The energy storage device comprises a housing, an electric core, an insulation film and the end cover assembly according to any one of claims 1-10, the electric core is accommodated in the housing, the end cover assembly is mounted on one side of the electric core and sealed in the housing, the explosion-proof support and the support frame are both abutted to the electric core, and the insulation film is wrapped on the circumferential side and the bottom surface of the electric core and connected with the lower plastic.

12. An energy storage system characterized by, The energy storage system comprises the energy storage device according to claim 11.

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