End cap assembly, energy storage device, and power supply system

Abstract

The application discloses an end cover assembly, an energy storage device and a power supply system. The end cover assembly comprises an end plate and an insulation assembly. The end plate comprises a body and an end part. The body comprises a first section and a second section. The first section is connected with the second section at both ends along the length direction of the end plate. Each second section is connected with the end part at the end away from the first section. The first section is provided with an explosion-proof valve. The end part is provided with a pole. The insulation assembly is arranged on one side of the end plate in the thickness direction and comprises a first lower plastic, a second lower plastic and an insulation layer arranged separately. The first lower plastic corresponds to the position of the first section. The second lower plastic corresponds to the position of the end part. The insulation layer corresponds to the position of the second section. The first lower plastic covers the explosion-proof valve. The second lower plastic is connected with the pole on the corresponding end part. The insulation layer covers one side surface of the corresponding second section. The thickness of the insulation layer is less than the thickness of the first lower plastic. The thickness of the insulation layer is less than the thickness of the second lower plastic.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and more specifically, to an end cap assembly, an energy storage device, and a power supply system. Background Technology

[0002] A rechargeable battery, also known as a secondary battery or storage battery, is a battery that can be recharged after being discharged, allowing the active materials to be reactivated and reused. The recyclable nature of rechargeable batteries has made them a primary power source for electrical devices. As the demand for rechargeable batteries increases, higher requirements are being placed on battery safety. Utility Model Content

[0003] This application provides an end cap assembly, an energy storage device, and a power supply system to meet the higher requirements for battery safety.

[0004] The end cap assembly of this application embodiment includes an end plate and an insulating assembly. The end plate includes a body and an end portion. The body includes a first segment and a second segment. The first segment is connected to the second segment at both ends along the length direction of the end plate, and the end portion is connected to the end portion at the end of each second segment away from the first segment. The first segment is provided with an explosion-proof valve, and the end portion is provided with a pole post. The insulating assembly is disposed on one side of the end plate in the thickness direction and includes a first lower plastic, a second lower plastic, and an insulating layer separately disposed. The first lower plastic corresponds to the position of the first segment, the second lower plastic corresponds to the position of the end portion, and the insulating layer corresponds to the position of the second segment. The first lower plastic covers the explosion-proof valve, the second lower plastic is connected to the pole post on the corresponding end portion, and the insulating layer covers one side surface of the corresponding second segment. The thickness of the insulating layer is less than the thickness of the first lower plastic; and / or, the thickness of the insulating layer is less than the thickness of the second lower plastic.

[0005] According to some embodiments of this application, along the length direction of the end plate, the size of the insulating layer is larger than the size of the first lower plastic, and the size of the insulating layer is larger than the size of the second lower plastic.

[0006] According to some embodiments of this application, the insulating layer has a first extension located between the first lower plastic and the first segment; and / or, the insulating layer has a second extension located between the corresponding second lower plastic and the end segment.

[0007] According to some embodiments of this application, a connector is fixedly connected to the side of the first segment facing the first lower plastic, the orthographic projection of the explosion-proof valve on the plane where the end plate is located is a first projection, the orthographic projection of the connector on the plane where the end plate is located is a second projection, at least a portion of the first projection falls within the area defined by the outer contour of the second projection, the first lower plastic is connected to the connector, and the first lower plastic covers the connector.

[0008] According to some embodiments of this application, the connector includes a base and a bending portion. The base has bending portions at both ends along the width direction of the end plate. Each bending portion bends from the base toward the end plate, and each bending portion has a first flange at the end away from the base that bends toward the explosion-proof valve. The first flange is connected to the first segment.

[0009] According to some embodiments of this application, the first flange is provided with a welding part, which is welded to the first segment; along the thickness direction of the end plate, the base is provided with a first through hole at the position corresponding to the welding part.

[0010] According to some embodiments of this application, along the thickness direction of the end plate, a second through hole is provided at the position corresponding to the first through hole in the first lower plastic.

[0011] According to some embodiments of this application, the connector further includes a reinforcing portion connected between the bent portion and the base portion.

[0012] According to some embodiments of this application, one of the connector and the first lower plastic is provided with a fastener, and the other is provided with a locking hole, wherein the fastener is used to be engaged into the locking hole.

[0013] According to some embodiments of this application, one of the first segment and the first lower plastic is provided with a first positioning part, and the other is provided with a second positioning part that positions and cooperates with the first positioning part.

[0014] According to some embodiments of this application, one of the first positioning part and the second positioning part is a protrusion and the other is a groove, with the protrusion positioned within the groove.

[0015] According to some embodiments of this application, the first lower plastic includes a cover and an extension. The cover has the extension at both ends along the length direction of the end plate. The cover has a receiving groove. At least a portion of the connector is disposed in the receiving groove. The extensions at both ends of the cover cover cover both ends of the explosion-proof valve along the length direction of the end plate. Each extension extends from the cover towards the end plate and is used to abut against the end plate.

[0016] According to some embodiments of this application, each of the extensions has a first groove on one side surface facing the end plate and at a position corresponding to the explosion-proof valve.

[0017] According to some embodiments of this application, the bottom of the first groove of each extension is provided with a through third through hole.

[0018] According to some embodiments of this application, the body has a second groove on the side facing the first lower plastic, the second groove extends along the length direction of the end plate, and a portion of each insulating layer is connected to the inner wall of the second groove.

[0019] According to some embodiments of this application, the sum of the areas of the first lower plastic and each of the second lower plastics projected onto a projection plane is S1, and the area of ​​the end plate projected onto the projection plane is S. S1 and S satisfy: 0.2≤S1 / S≤0.7; the projection plane is perpendicular to the thickness direction of the end plate.

[0020] According to some embodiments of this application, S1 and S satisfy: 0.3≤S1 / S≤0.45.

[0021] According to some embodiments of this application, the insulating layer is an insulating tape or an insulating coating.

[0022] The energy storage device according to the present application includes a housing, an electrode assembly, and an end cap assembly as described in any one of the above claims. The housing includes a receiving cavity with an opening; the electrode assembly is disposed within the receiving cavity; and the end cap assembly closes the opening of the housing.

[0023] According to some embodiments of this application, the electrode assembly is provided with an insulating sheet on the side facing the end cap assembly and at a position corresponding to the body of the end plate of the end cap assembly.

[0024] According to some embodiments of this application, the insulating sheet and each end of the end plate have overlapping regions on a projection plane, and the projection plane is perpendicular to the thickness direction of the end plate.

[0025] According to some embodiments of this application, the insulating sheet is provided with a plurality of through fourth holes.

[0026] According to some embodiments of this application, the insulating sheet has second flanges at both ends along the width direction of the end plate, and the second flanges at both ends of the insulating sheet are respectively attached to two side surfaces of the electrode assembly arranged along the width direction of the end plate.

[0027] According to some embodiments of this application, the second lower plastic of the end cap assembly is provided with a protrusion for abutting against the electrode assembly.

[0028] According to some embodiments of this application, the dimension of the connector of the end cap assembly along the width direction of the end plate is W1, and the distance between the two inner wall surfaces of the outer shell arranged along the width direction of the end plate is W. W1 and W satisfy: 0.5mm≤W-W1≤12mm.

[0029] The power supply system of this application embodiment includes electrical equipment and the energy storage device described in any of the above claims, wherein the energy storage device supplies power to the electrical equipment. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0031] Figure 1 This is a schematic diagram of an energy storage system.

[0032] Figure 2 This is a schematic diagram of a single-cell battery.

[0033] Figure 3 yes Figure 2 A schematic diagram of its breakdown.

[0034] Figure 4 yes Figure 3 An exploded view of the end cap assembly.

[0035] Figure 5 yes Figure 3 Another exploded view of the end cap assembly, omitting the conductive components and explosion-proof valve.

[0036] Figure 6 yes Figure 4 An exploded view of the connector and the first lower plastic piece.

[0037] Figure 7 It is along Figure 2 A cross-sectional view after being cut along section line AA.

[0038] Figure 8 yes Figure 7 A magnified view of the area at point X1.

[0039] Figure 9 This is a schematic diagram of a power supply system.

[0040] The reference numerals in the attached figures are explained as follows: 10. Housing; 11. Opening; 12. Receiving cavity; 20. Electrode assembly; 30. End cap assembly; 100. End plate; 101. Explosion-proof valve; 102. Pole post; 110. Body; 111. First section; 112. Second section; 113. Second positioning part; 114. Second groove; 120. End; 200, Insulating component; 210, First lower plastic part; 211, Second through hole; 212, Fastener; 213, First positioning part; 214, Cover part; 2141, Receiving groove; 215, Extension part; 216, First groove; 2161, Third through hole; 220, Second lower plastic part; 221, Protrusion; 230, Insulating layer; 231, First extension part; 232, Second extension part; 300. Connector; 310. Base; 311. First through hole; 320. Bending part; 330. First flange; 331. Welded part; 340. Reinforcing part; 350. Locking hole; 400, Insulating sheet; 401, Fourth through hole; 410, Substrate; 420, Second flange; 500. Conductive components. Detailed Implementation

[0041] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed description will be omitted.

[0042] It is understood that the terms "comprising" and "having," and any variations thereof, in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to these processes, methods, products, or devices.

[0043] For ease of explanation, the terms "X-axis direction," "Y-axis direction," and "Z-axis direction" are used in the specific embodiments of this application. These terms simply refer to a feature having one of these directions being perpendicular to a feature having the other direction; they do not require implementation according to the "X-axis direction," "Y-axis direction," and "Z-axis direction" described in the embodiments. In the embodiments, the X-axis direction, Y-axis direction, and Z-axis direction are mutually perpendicular.

[0044] Unless otherwise specified, in the claims and description, the terms “top,” “bottom,” “inner,” “outer,” “upper,” “lower,” “front,” “rear,” “left,” “right,” etc., indicate the orientation or positional relationship based on the orientation and positional relationship shown in the drawings, and are only for the purpose of simplifying the description, and do not imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation.

[0045] Because the energy people need is highly time- and space-dependent, in order to make rational use of energy and improve energy efficiency, it is necessary to use a medium or device to store one form of energy in the same way or by converting it into another form of energy, and then release it in a specific form of energy based on future application needs.

[0046] Currently, the generation of green electricity generally relies on solar, wind, and hydropower. However, wind and solar power are generally characterized by strong intermittency and large fluctuations, which can cause grid instability, insufficient power during peak demand periods, and excessive power during off-peak periods. Unstable voltage can also damage the power grid. Therefore, insufficient electricity demand or insufficient grid capacity may lead to the problem of "wind and solar curtailment." 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.

[0047] 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.

[0048] 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 energy storage cabinets applied to the electricity consumption side mainly function as self-consumption of electricity, peak-valley price arbitrage, capacity cost management, and improvement of power supply reliability. Depending on the application scenario, electricity consumption side energy storage can be divided into industrial and commercial energy storage cabinets, household energy storage devices, energy storage charging piles, etc., which are generally used in conjunction with distributed photovoltaics. Industrial and commercial users can use energy storage for peak-valley price arbitrage and capacity cost management. In the electricity market implementing peak-valley pricing, by charging the energy storage system when the electricity price is low and discharging the energy storage system when the electricity price is high, peak-valley price arbitrage can be achieved, reducing electricity costs. In addition, industrial enterprises subject to two-part tariffs can use energy storage systems to store energy during off-peak hours and discharge during peak loads, thereby reducing peak power and the maximum demand declared, achieving the goal of reducing capacity costs. Household photovoltaics with energy storage can improve the level of self-consumption of electricity. Due to high electricity prices and poor power supply stability, the demand for household photovoltaic installations is driven. Given that photovoltaic power generation occurs during the day, while user load is generally higher at night, configuring energy storage can better utilize photovoltaic power, improve self-consumption levels, and reduce electricity costs. Furthermore, energy storage is needed in areas such as communication base stations and data centers for backup power.

[0049] In some embodiments, see Figure 1 , Figure 1 This is a schematic diagram of the structure of an energy storage system according to an embodiment of this application, and Figure 1 Taking the shared energy storage scenario on the power generation / distribution side as an example, the energy storage device in this application is not limited to the power generation / distribution side energy storage scenario.

[0050] This application provides an energy storage system, comprising: a high-voltage cable 2, a first power conversion device 3, a second power conversion device 4, and the energy storage device 1 provided in this application. In some embodiments of the power generation scenario, the second power conversion device 4 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 1 through grid connection. The energy storage device 1 is connected to the high-voltage cable 2 and outputs smooth electricity to the power consumption side of the distribution network, realizing peak shaving and frequency regulation, and ensuring stable grid operation; or, the wind power conversion device is always connected to the high-voltage cable 2. High-voltage cable 2 connects the wind power conversion device to the power distribution network under normal power generation conditions. When the current power load is low and the wind power conversion device generates excess power, the excess power is first stored in energy storage device 1 to reduce wind and solar curtailment and improve the absorption of new energy power generation. When the power load is high, the power grid issues an instruction to transmit the power stored in energy storage device 1 in conjunction with high-voltage cable 2 in grid-connected mode to the power consumption side. This provides the power grid with various services such as peak shaving, frequency regulation, and backup, giving full play to the peak shaving function of the power grid, promoting peak shaving and valley filling, and alleviating the power supply pressure on the power grid.

[0051] In some embodiments on the distribution network side, the first power conversion device 3 can be a photovoltaic power conversion device. The energy storage device 1 is connected to the high-voltage cable 2 and installed downstream of the high-voltage cable 2 between the user load and the high-voltage cable 2. The power output of the photovoltaic power conversion device is stored in the energy storage device 1, which can respond in time to act as a backup power source when the power grid / distribution network fails. Alternatively, it can provide power supply support to alleviate line blockage when the high-voltage cable 2 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.

[0052] Optionally, the first power conversion device 3 may include, but is not limited to, a wind power conversion device, and the second power conversion device 4 may include, but is not limited to, a photovoltaic power conversion device. The first power conversion device 3 and the second power conversion device 4 can convert at least one of solar energy, light energy, wind energy, thermal energy, tidal energy, biomass energy and mechanical energy into electrical energy.

[0053] Optionally, the energy storage device 1 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.

[0054] Optionally, the energy storage device 1 may include, but is not limited to, individual batteries, battery packs, battery clusters, mobile power supplies, energy storage cabinets / containers, and other battery integrated systems. The actual application form of the energy storage device 1 provided in this application embodiment may be, but is not limited to, the listed products, and may also be other application forms. This application embodiment does not strictly limit the application form of the energy storage device 1.

[0055] like Figure 2 and Figure 3 As shown, the energy storage device 1 is a single battery cell. The single battery cell includes a housing 10, an electrode assembly 20, and an end cap assembly 30. The housing 10 includes a receiving cavity 12 with an opening 11. The electrode assembly 20 is disposed in the receiving cavity 12 through the opening 11. The end cap assembly 30 seals the opening 11 of the housing 10.

[0056] The electrode assembly 20 includes a positive electrode, a negative electrode, and a separator. The single-cell battery primarily operates by the movement of metal ions between the positive and negative electrode plates. The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector, and the uncoated positive current collector protrudes beyond the coated positive current collector, serving as the positive electrode tab. Taking a lithium-ion battery as an example, the positive current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector, and the uncoated negative current collector protrudes beyond the coated negative current collector, serving as the negative electrode tab. The negative current collector can be made of copper, and the negative active material can be carbon or silicon, etc. The material of the separator can be PP or PE, etc. In addition, the electrode assembly 20 can be a wound structure or a stacked structure, and the embodiments of this application are not limited to this.

[0057] The positive and negative tabs of the electrode assembly 20 can be located at the same end of the electrode assembly 20 or at opposite ends of the electrode assembly 20. This application does not limit this.

[0058] Alternatively, the single cell is not limited to at least one of cylindrical, square, prismatic, or other shaped cells.

[0059] Optionally, the single cell can be a rechargeable battery, which refers to a single cell that can be recharged after discharge to activate the active materials and continue to be used. The single cell 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 it.

[0060] like Figure 4 As shown, the end cap assembly 30 includes an end plate 100, an insulating assembly 200, and two conductive elements 500. The end plate 100 is equipped with an explosion-proof valve 101 and two terminals 102, one of which serves as the positive terminal and the other as the negative terminal. The explosion-proof valve 101 can be positioned between the two terminals 102 to rupture when the gas pressure inside the casing 10 reaches a threshold, thereby releasing the gas inside the casing 10 and preventing the battery from bulging or even exploding, thus improving battery safety. The insulating assembly 200 is located on the side of the end plate 100 facing the electrode assembly 20, and is used to electrically isolate the end plate 100 from the electrode assembly 20. The positive and negative tabs of the electrode assembly 20 are electrically connected to the two conductive elements 500, and the two conductive elements 500 are also electrically connected to the two terminals 102, allowing the electrical energy of the electrode assembly 20 to be conducted to the two terminals 102 through the two conductive elements 500.

[0061] In one exemplary embodiment, the length direction of the end plate 100 is the X-axis direction, the width direction of the end plate 100 is the Y-axis direction, and the thickness direction of the end plate 100 is the Z-axis direction.

[0062] The inventors of this application discovered in their research that the insulating component 200 in related technologies is typically a flat plate structure (lower plastic) made of plastic material, such as polypropylene. The lower plastic is positioned between the end plate 100 and the electrode assembly 20 to electrically isolate the end plate 100 and the electrode assembly 20, preventing electrical conduction between them. When the battery experiences thermal runaway, the explosion-proof valve 101 opens to release pressure, and a continuous reaction occurs inside the battery, generating high-temperature, high-pressure gas. As the gas temperature rises, the lower plastic begins to melt, and the positive electrode of the electrode assembly 20 begins to melt and form molten beads. The molten lower plastic and molten beads, along with the gas, are ejected from the outlet of the explosion-proof valve 101. After being ejected, the lower plastic carbonizes, and the resulting debris and molten beads accumulate at the outlet of the explosion-proof valve 101. As the temperature at the explosion-proof valve 101 port continues to rise, and the molten beads continue to come into contact with the debris, the debris formed after the lower plastic carbonizes is prone to reach the ignition point and be ignited, causing a fire. The burning battery will trigger a chain reaction and affect the surrounding batteries, causing serious consequences.

[0063] The inventors of this application further discovered that the lower plastic in the related technology is usually composed of a single flat plate structure, the size of which is basically the same as the size of the end plate 100. Because the lower plastic uses a large amount of plastic material, a large amount of it is ejected from the explosion-proof valve 101 after melting. This increases the amount of carbonized debris and the probability of it contacting molten beads, thus increasing the probability of fire.

[0064] To solve the above problems, such as Figure 4 and Figure 5As shown, the end plate 100 of this application embodiment includes a body 110 and an end 120. The body 110 includes a first segment 111 and a second segment 112. The two ends of the first segment 111 along the length direction (X-axis direction) of the end plate 100 are respectively connected to the second segment 112. The end of each second segment 112 away from the first segment 111 is connected to the end 120. The first segment 111 is provided with an explosion-proof valve 101, and the end 120 is provided with a pole post 102. An insulating component 200 is disposed on one side of the end plate 100 in the thickness direction (Z-axis direction) and includes a first lower plastic 210, a second lower plastic 220, and an insulating layer 230, which are separately disposed. The first lower plastic 210 corresponds to the position of the first segment 111, the second lower plastic 220 corresponds to the position of the end 120, and the insulating layer 230 corresponds to the position of the second segment 112. The first lower plastic 210 covers the explosion-proof valve 101, the second lower plastic 220 is connected to the pole post 102 on the corresponding end 120, and the insulating layer 230 covers one side surface of the corresponding second segment 112. The thickness of the insulating layer 230 is less than the thickness of the first lower plastic 210; and / or, the thickness of the insulating layer 230 is less than the thickness of the second lower plastic 220.

[0065] In this embodiment, the insulating component 200, comprising a first lower plastic 210, a second lower plastic 220, and an insulating layer 230, adopts a separate design. The thickness of the insulating layer 230 is less than the thickness of the first lower plastic 210, and / or, the thickness of the insulating layer 230 is less than the thickness of the second lower plastic 220. The first lower plastic 210 corresponds to the position of the first segment 111 of the end plate 100, the second lower plastic 220 corresponds to the position of the end portion 120 of the end plate 100, and the insulating layer 230 corresponds to the position of the second segment 112. Under this structural design, on the one hand, the first lower plastic 210, the second lower plastic 220, and the insulating layer 230... Layer 230 is located on one side of end plate 100, ensuring the insulation effect on one side of end plate 100. On the other hand, compared with the first lower plastic 210 and the second lower plastic 220, the insulation layer 230 is thinner. Therefore, compared with the design of using a whole piece of lower plastic in related technologies, this embodiment significantly reduces the overall material usage of the insulation component 200, thereby reducing the amount of insulation component 200 ejected from the explosion-proof valve 101 port after melting. In addition, the amount of debris formed after carbonization of insulation component 200 and the probability of contact with molten beads are reduced, thereby reducing the probability of insulation component 200 catching fire and improving battery safety.

[0066] In one embodiment, the end plate 100 includes a body 110 and two ends 120, which are respectively connected to both ends of the body 110 along the X-axis. One end 120 is provided with a positive terminal, and the other end 120 is provided with a negative terminal. The body 110 includes a first segment 111 and two second segments 112, with the first segment 111 connected between the two second segments 112, and the ends of the two second segments 112 away from the first segment 111 respectively connected to the two ends 120.

[0067] In one exemplary embodiment, the first segment 111 is located at the midpoint of the body 110 along the X-axis. In other words, the two second segments 112 are equal in size along the X-axis.

[0068] Of course, in other embodiments, the first segment 111 may not be located in the middle of the body 110 along the X-axis direction. For example, the first segment 111 may be located near the positive terminal or near the negative terminal.

[0069] In one exemplary embodiment, the insulating layer 230 is an insulating tape or an insulating coating.

[0070] In this embodiment, the insulating layer 230 is an insulating tape or an insulating coating. The insulating layer 230 is relatively thin. Under the premise of ensuring insulation performance, it can minimize the amount of material used in the insulating component 200, further reducing the amount of the insulating component 200 that is ejected from the explosion-proof valve 101 after melting, and reducing the probability of the insulating component 200 catching fire.

[0071] When the insulating layer 230 is an insulating tape, it can be a polyimide tape (PI tape) and is adhered to the surface of the corresponding second segment 112 facing the electrode assembly 20. When the insulating layer 230 is an insulating coating, it can be an insulating varnish, a ceramic coating, etc.

[0072] Please continue reading. Figure 4 and Figure 5 Along the length direction (X-axis direction) of the end plate 100, the size of the insulating layer 230 is larger than the size of the first lower plastic 210, and the size of the insulating layer 230 is larger than the size of the second lower plastic 220.

[0073] With the length of the end plate 100 remaining constant, the larger the dimension of the insulating layer 230 along the X-axis, the smaller the dimensions of the first lower plastic 210 and the second lower plastic 220 along the X-axis can be. In this embodiment, by designing the insulating layer 230 to be larger than the first lower plastic 210 and the second lower plastic 220 along the X-axis, the amount of material used in the thicker first lower plastic 210 and the second lower plastic 220 is further compressed, thereby further reducing the overall material usage of the insulating component 200. This reduces the amount of material ejected from the explosion-proof valve 101 port after the insulating component 200 melts, and also reduces the amount of debris formed after the insulating component 200 carbonizes and the probability of it contacting molten beads, further reducing the probability of the insulating component 200 catching fire.

[0074] In one embodiment, the insulating layer 230 has a first extension 231 located between the first lower plastic 210 and the first segment 111; and / or, the insulating layer 230 has a second extension 232 located between the corresponding second lower plastic 220 and the end 120.

[0075] In this embodiment, by disposing the first extension 231 of the insulating layer 230 between the first lower plastic 210 and the first segment 111, and / or disposing the second extension 232 between the corresponding second lower plastic 220 and the end 120, the insulating layer 230 and the first lower plastic 210 and / or the second lower plastic 220 have overlapping areas in the Z-axis direction. The insulation performance of the overlapping areas is further enhanced, thereby improving the overall insulation performance of the insulating component 200 and preventing short circuits between the electrode component 20 and the end plate 100 due to gaps between the first lower plastic 210 and the insulating layer 230, and / or between the second lower plastic 220 and the insulating layer 230.

[0076] like Figure 5 As shown, the body 110 has a second groove 114 on the side facing the first lower plastic 210. The second groove 114 extends along the length direction (X-axis direction) of the end plate 100, and a portion of each insulating layer 230 is connected to the inner wall of the second groove 114.

[0077] In this embodiment, a second groove 114 is provided on the side of the body 110 facing the electrode assembly 20. The provision of the second groove 114 increases the distance between the bottom wall of the second groove 114 and the electrode assembly 20, allowing the electrode assembly 20 to be moved away from the end plate 100, reducing the risk of short circuit due to conduction between the electrode assembly 20 and the end plate 100. In addition, the second groove 114 can also enhance the overall structural strength of the end plate 100, preventing problems such as bending of the end plate 100 or collapse of the middle region along the length of the end plate 100 due to excessive length.

[0078] In one embodiment, the second groove 114 is formed on the end plate 100 by a stamping process.

[0079] In an exemplary embodiment, one end of the second groove 114 is close to one of the end portions 120 along the X-axis, and the other end is close to the other end portion 120. In other words, along the X-axis, the second groove 114 spans the two second segments 112 and the first segment 111 of the body 110.

[0080] In one embodiment, the sum of the areas of the first lower plastic 210 and each of the second lower plastics 220 projected onto a projection plane is S1, and the area of ​​the end plate 100 projected onto the projection plane is S. S1 and S satisfy: 0.2≤S1 / S≤0.7. The projection plane is perpendicular to the thickness direction (Z-axis direction) of the end plate 100.

[0081] With the thickness of the first lower plastic 210 and each of the second lower plastics 220 remaining constant, a larger S1 indicates that more material is used in the first lower plastic 210 and each of the second lower plastics 220, making it easier for them to ignite in the event of thermal runaway. However, a larger S1 ensures that the area of ​​the hot melt zone between the first lower plastic 210 and each of the second lower plastics 220 and the electrode assembly 20 is large enough, thereby ensuring the firmness of the connection between the first lower plastic 210 and each of the second lower plastics 220 and the electrode assembly 20. A smaller S1 indicates that less material is used in the first lower plastic 210 and each of the second lower plastics 220, resulting in a lower probability of ignition in the event of thermal runaway. However, if S1 is too small, it cannot ensure that the area of ​​the hot melt zone between the first lower plastic 210 and each of the second lower plastics 220 and the electrode assembly 20 is large enough, thus affecting the firmness of the connection between the first lower plastic 210 and each of the second lower plastics 220 and the electrode assembly 20. Therefore, in this embodiment, S1 and S satisfy: 0.2≤S1 / S≤0.7. Under the premise of ensuring that the first lower plastic 210 and each of the second lower plastics 220 have a sufficiently large hot melt zone area with the electrode assembly 20, the material usage of the first lower plastic 210 and the second lower plastic 220 is reduced as much as possible, thereby reducing the risk of fire of the first lower plastic 210 and the second lower plastic 220.

[0082] In one embodiment, S1 and S satisfy: 0.3≤S1 / S≤0.45.

[0083] like Figure 4 and Figure 5As shown, a connector 300 is fixed to the side of the first segment 111 facing the first lower plastic 210. The orthographic projection of the explosion-proof valve 101 on the plane of the end plate 100 is the first projection, and the orthographic projection of the connector 300 on the plane of the end plate 100 is the second projection. At least a portion of the first projection falls within the area defined by the outer contour of the second projection. The first lower plastic 210 is connected to the connector 300, and the first lower plastic 210 covers the connector 300.

[0084] In this embodiment, the connector 300 is fixedly connected to the first segment 111, and the connector 300 is located between the explosion-proof valve 101 and the first lower plastic 210. When the battery experiences thermal runaway, the electrode assembly 20 tends to move towards the end plate 100 after the first lower plastic 210 melts (i.e., the electrode assembly 20 floats up). At this time, the connector 300 can prevent the electrode assembly 20 from floating up further, thereby avoiding the problem of poor exhaust caused by the electrode assembly 20 blocking the outlet of the explosion-proof valve 101.

[0085] In one embodiment, the first projection of the connector 300 extends out of the area defined by the second projection of the explosion-proof valve 101 at both ends along the Y-axis direction.

[0086] In one exemplary embodiment, the connector 300 may be made of a metallic or ceramic material.

[0087] like Figure 6 As shown, the connector 300 includes a base 310 and a bending portion 320. The base 310 has bending portions 320 at both ends along the width direction (Y-axis direction) of the end plate 100. Each bending portion 320 bends from the base 310 toward the end plate 100, and each bending portion 320 has a first flange 330 at the end away from the base 310 that bends toward the explosion-proof valve 101. The first flange 330 is connected to the first segment 111.

[0088] In this embodiment, on the one hand, the bent portions 320 at both ends of the base 310 are bent towards the end plate 100, so that the base 310 can be moved away from the explosion-proof valve 101, avoiding accidental damage to the explosion-proof valve 101 when installing the connector 300. Moreover, the base 310 is spaced apart from the explosion-proof valve 101, and there is a sufficiently large gap between the base 310 and the explosion-proof valve 101 for gas to flow through. When thermal runaway occurs, the gap facilitates the rapid passage of gas and its rupture of the explosion-proof valve 101. On the other hand, the end of each bent portion 320 away from the base 310 is bent towards the explosion-proof valve 101. The first flange 330, that is, the first flange 330 is folded inward, can maximize the size of the base 310 along the Y-axis direction, so that the two ends of the base 310 along the Y-axis direction can be as close as possible to the inner wall of the outer shell 10. When thermal runaway occurs, since the size of the base 310 along the Y-axis direction is large enough, the area of ​​the base 310 facing the electrode assembly 20 is large. Thus, the base 310 can prevent the electrode assembly 20 from floating towards the end plate 100 due to thermal runaway, and avoid the electrode assembly 20 from floating up and blocking the exhaust channels at both ends of the connector 300 along the Y-axis direction.

[0089] like Figure 6 As shown, the first flange 330 is provided with a welding part 331, which is welded to the first segment 111. Along the thickness direction (Z-axis direction) of the end plate 100, the base 310 is provided with a first through hole 311 at a position corresponding to the welding part 331. Along the thickness direction (Z-axis direction) of the end plate 100, the first lower plastic 210 is provided with a second through hole 211 at a position corresponding to the first through hole 311.

[0090] In this embodiment, the welding part 331 is exposed through the first through hole 311 and the second through hole 211, so that the laser beam can pass through the second through hole 211 and the first through hole 311 to weld the welding part 331 to the first segment 111, avoiding the base 310 and the first lower plastic 210 from blocking the laser beam and causing welding failure.

[0091] like Figure 6 As shown, the connector 300 also includes a reinforcing portion 340, which is connected between the bent portion 320 and the base 310. By providing the reinforcing portion 340 between the bent portion 320 and the base 310, the bending strength of the bent portion 320 can be improved.

[0092] In one embodiment, the reinforcing part 340 is a raised rib, which is located on the inner side of the connection between the bent part 320 and the base part 310.

[0093] like Figure 6 As shown, one of the connector 300 and the first lower plastic 210 is provided with a fastener 212, and the other is provided with a locking hole 350. The fastener 212 is used to be inserted into the locking hole 350.

[0094] In this embodiment, the fastener 212 can be inserted into the card hole 350 to complete the assembly of the first plastic 210 and the connector 300, which improves the assembly efficiency.

[0095] In one embodiment, the base 310 is provided with at least one locking hole 350 at each end along the Y-axis direction, and fasteners 212 are provided at the positions corresponding to the locking holes 350 on the first lower plastic 210.

[0096] Of course, the connection between the connector 300 and the first lower plastic 210 is not limited to the connection between the fastener 212 and the locking hole 350. For example, the connector 300 may have a hole and the first lower plastic 210 may have a hot melt column. When assembling the first lower plastic 210 and the connector 300, the hot melt column is inserted into the hole and the top of the hot melt column is melted by heating to form a disc-shaped "mushroom head" with a diameter larger than the hole diameter.

[0097] like Figure 5 and Figure 6 As shown, one of the first segment 111 and the first lower plastic 210 is provided with a first positioning part 213, and the other is provided with a second positioning part 113 that is positioned and engaged with the first positioning part 213.

[0098] In this embodiment, during the assembly of the first lower plastic 210, the first positioning part 213 and the second positioning part 113 are positioned and cooperated, so that the first lower plastic 210 can be quickly installed to the predetermined position of the end plate 100, thereby improving the assembly efficiency.

[0099] In one embodiment, the first positioning part 213 and the second positioning part 113 are a protrusion and a groove, with the protrusion positioned in the groove.

[0100] For example, the first lower plastic 210 has a protrusion, and the first section 111 of the end plate 100 has a groove; or, the first lower plastic 210 has a groove, and the first section 111 of the end plate 100 has a protrusion.

[0101] The first positioning part 213 and the second positioning part 113 are not limited to using a protrusion and groove positioning engagement. In another embodiment, the first positioning part 213 and the second positioning part 113 may also use a stepped structure positioning engagement.

[0102] like Figure 6As shown, the first lower plastic 210 includes a cover portion 214 and an extension portion 215. The cover portion 214 has extension portions 215 at both ends along the length direction (X-axis direction) of the end plate 100. The cover portion 214 has a receiving groove 2141. At least a portion of the connector 300 is disposed in the receiving groove 2141. The extension portions 215 at both ends of the cover portion 214 respectively cover the two ends of the explosion-proof valve 101 along the length direction (X-axis direction) of the end plate 100. Each extension portion 215 extends from the cover portion 214 toward the end plate 100 and is used to abut against the end plate 100.

[0103] In this embodiment, since the extension 215 abuts against the end plate 100, the first lower plastic 210 can hold the end plate 100, and the end plate 100 strengthens the load-bearing capacity of the first lower plastic 210, preventing the first lower plastic 210 from being crushed by the electrode assembly 20 when the battery is inverted.

[0104] In one embodiment, each extension 215 is provided with one of a first positioning part 213 and a second positioning part 113.

[0105] In one embodiment, each extension 215 has a first groove 216 on the side surface facing the end plate 100 and at the position corresponding to the explosion-proof valve 101.

[0106] In this embodiment, the first groove 216 increases the distance between the bottom wall of the first groove 216 and the explosion-proof valve 101, so that the extension 215 of the first lower plastic 210 can be kept away from the explosion-proof valve 101, thus avoiding accidental damage to the explosion-proof valve 101 when assembling the first lower plastic 210.

[0107] In an exemplary embodiment, the shape of the first groove 216 is adapted to the shape of the end 120 of the explosion-proof valve 101.

[0108] like Figure 6 As shown, the bottom of the first groove 216 of each extension 215 is provided with a through third through hole 2161.

[0109] In this embodiment, when the battery experiences thermal runaway, the gas can flow from the side of the extension 215 away from the explosion-proof valve 101 through the third through hole 2161 to the side of the extension 215 facing the explosion-proof valve 101. The first groove 216 provides sufficient flow space for the gas, allowing the gas to be discharged in a timely manner.

[0110] like Figure 7 and Figure 8 As shown, the dimension of the connector 300 of the end cap assembly 30 along the width direction (Y-axis direction) of the end plate 100 is W1, and the distance between the two inner wall surfaces of the outer shell 10 arranged along the width direction (Y-axis direction) of the end plate 10 is W. W1 and W satisfy: 0.5mm≤W-W1≤12mm.

[0111] It should be noted that the electrode assembly 20 will expand after being immersed in the electrolyte. When thermal runaway occurs, after the first lower plastic 210 and each of the second lower plastics 220 melt and are ejected, the positive and / or negative electrode plates in the middle region of the electrode assembly 20 along the X-axis are relatively long due to their relatively long length. As a result, the electrode plates and / or negative electrode plates in the middle region are easily affected by the airflow and float towards the end plate 100. The floated positive and / or negative electrode plates will move upward from both sides of the first lower plastic 210 along the Y-axis and block the exhaust channel.

[0112] In this embodiment, W1 and W satisfy: 0.5mm≤W-W1≤12mm, that is, the dimension of the connector 300 along the Y-axis is slightly smaller than the distance between the two inner wall surfaces of the outer casing 10. In this way, when the positive electrode and / or negative electrode in the middle region of the electrode assembly 20 floats up, the connector 300 can prevent the positive electrode and / or negative electrode from continuing to move towards the end plate 100, thereby ensuring that the exhaust channels on both sides of the connector 300 along the Y-axis are unobstructed so that the gas can be discharged in time.

[0113] Conversely, if W-W1 < 0.5mm, it means that the single-sided gap between the two sides of the connector 300 along the Y-axis and the two inner walls of the housing 10 is less than 0.25mm. The single-sided gap is too small, which makes it difficult to assemble the end cap assembly 30 with the housing 10. As a result, metal scraping is easily generated when assembling the end cap assembly 30 with the housing 10. The metal scraping falls into the interior of the housing 10 during the assembly process and will puncture the separator, causing the positive and negative electrode plates to be electrically connected, thus forming an internal micro short circuit, which ultimately leads to battery thermal runaway.

[0114] If W1 and W satisfy: W-W1>12mm, it means that the single-sided gap between the two sides of the connector 300 along the Y-axis and the two inner walls of the outer casing 10 is greater than 6mm. With such a large gap, the connector 300 can prevent most of the electrode assembly 20 from floating, while some of the positive and / or negative electrode plates will float through the 6mm gap and eventually block the exhaust channel.

[0115] Please return to the reference. Figure 3 An insulating sheet 400 is provided on the side of the electrode assembly 20 facing the end cap assembly 30 and at a position corresponding to the body 110 of the end plate 100 of the end cap assembly 30.

[0116] In this embodiment, an insulating sheet 400 is also provided between the body 110 and the electrode assembly 20. The insulating sheet 400 can improve the insulation effect between the body 110 and the electrode assembly 20 and prevent the second segment 112 of the body 110 from being connected to the electrode assembly 20.

[0117] In one embodiment, the orthographic projections of the insulating sheet 400 and each end 120 of the end plate 100 on the projection plane overlap in some areas.

[0118] In this embodiment, the insulating sheet 400 not only covers the body 110 of the end plate 100, but also covers each end 120 of the end plate 100. This not only improves the insulation between the body 110 and the electrode assembly 20, but also improves the insulation between the end 120 and the electrode assembly 20.

[0119] like Figure 3 As shown, the insulating sheet 400 includes a substrate 410 and a second flange 420. The substrate 410 covers the side of the electrode assembly 20 facing the end plate 100. The substrate 410 has a second flange 420 at both ends along the width direction (Y-axis direction) of the end plate 100. The second flanges 420 at both ends of the insulating sheet 400 are respectively attached to two side surfaces of the electrode assembly 20 arranged along the width direction (Y-axis direction) of the end plate 100.

[0120] In one embodiment, the second flange 420 may be bonded to the side surface of the electrode assembly 20.

[0121] like Figure 3 As shown, the substrate 410 of the insulating sheet 400 is provided with a plurality of through fourth through holes 401.

[0122] In this embodiment, the substrate 410 is provided with a plurality of fourth through holes 401. On the one hand, the electrolyte can be refluxed through the fourth through holes 401. On the other hand, the gas generated by the electrode assembly 20 can flow to the explosion-proof valve 101 through the fourth through holes 401.

[0123] In one embodiment, the insulating sheet 400 may be made of PP (Polypropylene) or PET (Polyethylene terephthalate).

[0124] like Figure 5 As shown, the second lower plastic 220 is provided with a protrusion 221 for abutting against the electrode assembly 20.

[0125] In this embodiment, the second lower plastic 220 is provided with a protrusion 221, which can abut against the electrode assembly 20, thereby ensuring that the electrode assembly 20 is always away from the end plate 100. This not only prevents the electrode assembly 20 from conducting with the end plate 100, but also prevents the electrode assembly 20 from floating towards the end plate 100 in the event of thermal runaway, ensuring that the exhaust channel between the electrode assembly 20 and the end plate 100 remains unobstructed.

[0126] "Abutting" refers to the force between the protrusion 221 and the electrode assembly 20, and the protrusion 221 may be in direct contact with the electrode assembly 20 or indirect contact with the electrode assembly 20.

[0127] like Figure 9 As shown, in another aspect of this application, a power supply system 6 is also provided, including an electrical device 5 and an energy storage device 1 of any of the above embodiments. The energy storage device 1 is electrically connected to the electrical device 5 and supplies power to the electrical device 5.

[0128] It is understood that the various embodiments / implementations provided in this application can be combined with each other without creating contradictions, and will not be described one by one here.

[0129] In the embodiments of this application, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise expressly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0130] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the claims. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0131] The above are merely preferred embodiments of the application examples and are not intended to limit the application examples. For those skilled in the art, the application examples can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the application examples should be included within the protection scope of the application examples.

Claims

1. An end cap assembly, characterized in that, include: An end plate includes a body and an end portion. The body includes a first section and a second section. The first section is connected to the second section at both ends along its length. The end portion is connected to the end portion at the end of each second section away from the first section. The first section is provided with an explosion-proof valve, and the end portion is provided with a pole post. An insulating component is disposed on one side of the end plate in the thickness direction and includes a first lower plastic, a second lower plastic and an insulating layer separately disposed. The first lower plastic corresponds to the position of the first segment, the second lower plastic corresponds to the position of the end, and the insulating layer corresponds to the position of the second segment. The first lower plastic covers the explosion-proof valve, the second lower plastic is connected to the pole on the corresponding end, and the insulating layer covers one side surface of the corresponding second segment. The thickness of the insulating layer is less than the thickness of the first lower plastic; and / or, the thickness of the insulating layer is less than the thickness of the second lower plastic.

2. The end cap assembly according to claim 1, characterized in that, Along the length of the end plate, the size of the insulating layer is larger than the size of the first lower plastic, and the size of the insulating layer is larger than the size of the second lower plastic.

3. The end cap assembly according to claim 1, characterized in that, The insulating layer has a first extension located between the first lower plastic and the first segment; and / or, the insulating layer has a second extension located between the corresponding second lower plastic and the end segment.

4. The end cap assembly according to claim 1, characterized in that, The first segment is fixedly connected to a connector on the side facing the first lower plastic. The orthographic projection of the explosion-proof valve on the plane where the end plate is located is a first projection, and the orthographic projection of the connector on the plane where the end plate is located is a second projection. At least a portion of the first projection falls within the area defined by the outer contour of the second projection. The first lower plastic is connected to the connector, and the first lower plastic covers the connector.

5. The end cap assembly according to claim 4, characterized in that, The connector includes a base and a bending portion. The base has bending portions at both ends along the width direction of the end plate. Each bending portion bends from the base toward the end plate, and each bending portion has a first flange at the end away from the base that bends toward the explosion-proof valve. The first flange is connected to the first segment.

6. The end cap assembly according to claim 5, characterized in that, The first flange is provided with a welding part, which is welded to the first segment; along the thickness direction of the end plate, the base is provided with a first through hole at the position corresponding to the welding part.

7. The end cap assembly according to claim 6, characterized in that, Along the thickness direction of the end plate, a second through hole is provided at the position corresponding to the first through hole in the first lower plastic.

8. The end cap assembly according to claim 5, characterized in that, The connector further includes a reinforcing portion connected between the bent portion and the base portion.

9. The end cap assembly according to claim 4, characterized in that, One of the connectors and the first lower plastic part is provided with a fastener, and the other is provided with a locking hole. The fastener is used to lock into the locking hole.

10. The end cap assembly according to claim 4, characterized in that, The first segment and the first lower plastic part are provided with a first positioning part, and the other part is provided with a second positioning part that positions and cooperates with the first positioning part.

11. The end cap assembly according to claim 10, characterized in that, The first positioning part and the second positioning part are respectively a protrusion and a groove, and the protrusion is positioned in the groove.

12. The end cap assembly according to claim 4, characterized in that, The first lower plastic part includes a cover and an extension. The cover has the extension at both ends along the length of the end plate. The cover has a receiving groove. At least a portion of the connector is disposed in the receiving groove. The extensions at both ends of the cover cover cover both ends of the explosion-proof valve along the length of the end plate. Each extension extends from the cover towards the end plate and is used to abut against the end plate.

13. The end cap assembly according to claim 12, characterized in that, Each of the extensions has a first groove on the side surface facing the end plate and at the position corresponding to the explosion-proof valve.

14. The end cap assembly according to claim 13, characterized in that, The bottom of the first groove of each extension is provided with a through third hole.

15. The end cap assembly according to claim 1, characterized in that, The body has a second groove on the side facing the first lower plastic, the second groove extends along the length of the end plate, and a portion of each insulating layer is connected to the inner wall of the second groove.

16. The end cap assembly according to claim 1, characterized in that, The sum of the areas of the first lower plastic and each of the second lower plastics projected onto a projection plane is S1, and the area of ​​the end plate projected onto the projection plane is S. S1 and S satisfy: 0.2≤S1 / S≤0.7; the projection plane is perpendicular to the thickness direction of the end plate.

17. The end cap assembly according to claim 16, characterized in that, S1 and S satisfy: 0.3≤S1 / S≤0.

45.

18. The end cap assembly according to claim 1, characterized in that, The insulating layer is an insulating tape or an insulating coating.

19. An energy storage device, characterized in that, include: The housing includes a receiving cavity with an opening; The electrode assembly is disposed within the receiving cavity; The end cap assembly according to any one of claims 1-18, which closes the opening of the housing.

20. The energy storage device according to claim 19, characterized in that, An insulating sheet is provided on the side of the electrode assembly facing the end cap assembly and at a position corresponding to the body of the end plate of the end cap assembly.

21. The energy storage device according to claim 20, characterized in that, The insulating sheet and each end of the end plate have overlapping areas when projected onto a projection plane, and the projection plane is perpendicular to the thickness direction of the end plate.

22. The energy storage device according to claim 20, characterized in that, The insulating sheet has multiple through-holes.

23. The energy storage device according to claim 20, characterized in that, The insulating sheet has a second flange at each end along the width direction of the end plate, and the second flanges at both ends of the insulating sheet are respectively attached to the two side surfaces of the electrode assembly arranged along the width direction of the end plate.

24. The energy storage device according to claim 19, characterized in that, The second lower plastic part of the end cap assembly has a protrusion for abutting against the electrode assembly.

25. The energy storage device according to claim 19, characterized in that, The dimension of the connector of the end cap assembly along the width direction of the end plate is W1, and the distance between the two inner wall surfaces of the outer shell arranged along the width direction of the end plate is W. W1 and W satisfy: 0.5mm≤W-W1≤12mm.

26. A power supply system, characterized in that, It includes electrical equipment and an energy storage device as described in any one of claims 19-25, wherein the energy storage device supplies power to the electrical equipment.

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