Lower plastic, top cover assembly, energy storage device and electric appliance

Abstract

The application provides a lower plastic, a top cover assembly, an energy storage device and an electrical equipment. The lower plastic comprises a plastic body, a plurality of bosses and a reinforcing member. The plastic body comprises a first side and a second side opposite in the thickness direction of the plastic body, and has a pressure relief valve area corresponding to a pressure relief valve of the energy storage device. The plurality of bosses are arranged on the second side of the plastic body. The plurality of bosses comprise a first boss group located on two sides of the pressure relief valve area in the length direction of the plastic body, and the first boss group is configured to block the movement of a winding core to the pressure relief valve area when the winding core of the energy storage device is in thermal runaway expansion. The reinforcing member is arranged on the second side of the plastic body and corresponds to the pressure relief valve area. The reinforcing member is connected with the plastic body and / or the first boss group, and is configured to block the movement of the winding core to the pressure relief valve area when the winding core is in thermal runaway expansion.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a lower plastic, a top cover assembly, an energy storage device, and an electrical device. Background Technology

[0002] As energy storage devices, such as batteries, increase in capacity, the amount of gas generated during thermal runaway within the battery also increases significantly. If this gas cannot be released in time, it can cause a sharp rise in internal battery pressure, even posing a risk of explosion. The design of the lower plastic component, a key structural element within the battery, directly impacts venting efficiency.

[0003] The plastic casing used in current high-capacity batteries generally suffers from poor venting. Especially after thermal runaway, the internal wound core (JR) expands and is carried upwards by rising airflow, easily blocking the internal venting channels. Current batteries lack effective measures to prevent this blockage, posing a safety hazard of battery casing rupture or even explosion due to poor venting. Summary of the Invention

[0004] In view of the above problems, this application provides a lower plastic, a top cover assembly, an energy storage device, and an electrical device.

[0005] In a first aspect, this application provides a lower plastic assembly for an energy storage device. The lower plastic assembly includes a plastic body, a plurality of bosses, and a reinforcing member. The plastic body includes a first side and a second side opposite to each other in the thickness direction of the plastic body, and has an explosion-proof valve region corresponding to the explosion-proof valve of the energy storage device. The plurality of bosses are disposed on the second side of the plastic body. The plurality of bosses include a first boss group located on both sides opposite to the explosion-proof valve region in the length direction of the plastic body. The first boss group is configured to prevent the core of the energy storage device from moving towards the explosion-proof valve region during thermal runaway expansion. The reinforcing member is disposed on the second side of the plastic body and corresponds to the explosion-proof valve region. The reinforcing member is connected to the plastic body and / or the first boss group, and is configured to prevent the core from moving towards the explosion-proof valve region during thermal runaway expansion.

[0006] In the above technical solution, the lower plastic body constructs a blocking and protective structure for the explosion-proof valve area by setting a first protrusion group on both sides of the explosion-proof valve area at the bottom of the plastic body. When the energy storage device's core experiences thermal runaway, the first protrusion group effectively blocks the core from arching upwards and towards the center due to gas generation, preventing the core from directly impacting and blocking the exhaust area below the explosion-proof valve. This ensures smooth gas discharge, preventing the energy storage device's casing from rupturing or even exploding due to poor exhaust, thus improving the thermal safety performance of the energy storage device. Furthermore, the lower plastic body provides a redundant safety structure by incorporating reinforcing members. When the lower plastic body softens or melts due to thermal runaway of the energy storage device's core, the reinforcing members maintain rigidity, continuing to prevent the core from moving towards the explosion-proof valve area. This prevents the core from blocking the explosion-proof valve's opening due to loss of support in the later stages of thermal runaway, further improving the thermal safety performance of the energy storage device.

[0007] As an optional technical solution of this application, the first boss group includes a first boss, the first boss includes a first sidewall and a second sidewall opposite to each other in the length direction of the plastic body, and a third sidewall connecting the first sidewall and the second sidewall. The third sidewall is disposed opposite to the plastic body in the thickness direction of the plastic body. At least two of the first sidewall, the second sidewall and the third sidewall are provided with a first through hole to form a first exhaust channel.

[0008] In the above technical solution, first through holes are opened on multiple side walls of the first boss, transforming the solid boss used to block the core into a porous structure that also has a flow guiding function. In the event of thermal runaway of the energy storage device's core, gas can enter and pass through from multiple directions of the boss, increasing the gas flow channels and thus improving the efficiency of gas collection and discharge from the core to the explosion-proof valve area. This avoids pressure accumulation caused by localized airflow obstruction and enhances the thermal safety performance of the energy storage device.

[0009] As an optional technical solution of this application, when a first through hole is provided on the first sidewall and the second sidewall to form a first exhaust channel, the first through hole on the first sidewall is aligned with the first through hole on the second sidewall.

[0010] In the above technical solution, the lower plastic part forms a low-resistance, straight airflow channel through the boss by aligning the first through holes on the opposite side walls of the first boss assembly. During thermal runaway of the energy storage device's core, the gas can pass through the boss more directly and smoothly, reducing turbulence and pressure loss during gas flow, thereby optimizing exhaust efficiency and preventing excessive flow resistance from affecting the overall pressure relief rate, thus further improving the thermal safety performance of the energy storage device.

[0011] As an optional technical solution of this application, the plurality of protrusions further includes a second protrusion group located on opposite sides in the length direction X of the plastic body. In the length direction X, the second protrusion group is closer to the end of the plastic body than the first protrusion group. The second protrusion group is configured to prevent the core from moving toward the plastic body when the core of the energy storage device undergoes thermal runaway expansion.

[0012] In the above technical solution, the lower plastic body is constructed with a second set of protrusions on both sides to form a blocking and protective structure on both sides. When the core of the energy storage device experiences thermal runaway, the protrusions of the second set of protrusions can effectively limit the excessive expansion and movement of the core towards the side wall of the energy storage device's housing, preventing the core from being squeezed and damaged by the housing or the side of the lower plastic body, thus preventing internal short circuits. At the same time, it helps to maintain the shape of the first exhaust channel in the explosion-proof valve area, thereby indirectly ensuring smooth exhaust and improving the thermal safety performance of the energy storage device.

[0013] As an optional technical solution of this application, the second boss group includes a second boss, the second boss includes a first outer wall and a second outer wall opposite to each other in the length direction of the plastic body, and a third outer wall connecting the first outer wall and the second outer wall. The third outer wall is disposed opposite to the plastic body in the thickness direction of the plastic body. At least two of the first outer wall, the second outer wall and the third outer wall are provided with a second through hole to form a second exhaust channel.

[0014] In the above technical solution, a second through hole is opened on the side wall of the boss of the second boss group, so that the lateral blocking and protection structure also has efficient flow guiding capability. In the event of thermal runaway of the energy storage device's core, the gas gathered from the lateral exhaust gap can pass through the second boss group without obstruction, thus forming a highly efficient second exhaust channel. The second exhaust channel is connected to the first exhaust channel, thereby improving the entire exhaust network, avoiding the increase in exhaust load on the first exhaust channel due to insufficient lateral exhaust, and improving the thermal safety performance of the energy storage device.

[0015] As an optional technical solution of this application, in the length direction of the plastic body, the first outer wall is farther away from the explosion-proof valve area than the second outer wall, and the first outer wall is recessed by 2mm to 10mm from the end of the plastic body toward the explosion-proof valve area.

[0016] In the above technical solution, the lower plastic body is recessed by 2mm to 10mm from the end of the second boss assembly towards the explosion-proof valve area, forming a preset lateral venting gap between the end of the plastic body and the bosses of the second boss assembly. In the event of thermal runaway of the energy storage device's core, this lateral venting gap provides a low-resistance collection and upward channel for the gas generated in the electrolyte areas on both sides of the core, ensuring that this gas can be smoothly introduced into the upper venting network, avoiding the formation of flow dead zones at the edges and corners, which would lead to localized pressure increases. This achieves balanced venting throughout the entire lower plastic body, thereby improving the thermal safety performance of the energy storage device.

[0017] As an optional technical solution of this application, the second boss further includes a protrusion, which is connected to or integral with at least one of the first outer wall, the second outer wall and the third outer wall. The protrusion is provided with a third through hole to form a third exhaust channel, and the protrusion is configured to be connected to the Mylar membrane of the energy storage device.

[0018] In the above technical solution, the lower plastic material connects or integrates the protrusions used to connect the Mylar membrane with the protrusions of the second protrusion group forming the second exhaust channel, and opens a third through hole to form the third exhaust channel, thereby realizing the integration of the mechanical fixation and gas flow functions of the Mylar membrane.

[0019] As an optional technical solution of this application, the protrusion includes a connecting surface. In the length direction of the plastic body, the connecting surface is closer to the end of the plastic body than the first outer wall, and the connecting surface is configured to connect with the Mylar membrane of the energy storage device.

[0020] In the above technical solution, the connecting surface is closer to the end of the plastic body than the first outer wall, so a lateral venting gap is formed between the first outer wall and the end of the plastic body. This can avoid the formation of flow dead zones at the edge corners, which would lead to local pressure increases. At the same time, the presence of the connecting surface can also ensure that the fixing points of the Mylar membrane remain basically unchanged from those without the lateral venting gap, avoiding changes to the connection process of the Mylar membrane and saving costs.

[0021] As an optional technical solution of this application, the plastic body is provided with perforations and a mesh structure in the explosion-proof valve area. The perforations penetrate through a first side and a second side of the plastic body. The mesh structure is disposed on the second side of the plastic body or within the perforations. In a plane perpendicular to the thickness direction of the plastic body, the projection of the mesh structure covers the projection of the perforations, and the total opening area of ​​the mesh structure accounts for 50% or more of the total area of ​​the mesh structure.

[0022] In the above technical solution, the lower plastic layer creates a protective interface that combines breathability and mechanical strength by setting a high-aperture mesh structure in the area directly opposite the explosion-proof valve. During thermal runaway of the energy storage device's core, the high porosity of the mesh structure significantly reduces gas flow resistance, ensuring smooth venting. Simultaneously, the mesh shape effectively intercepts and supports solid particles carried by the gas, preventing direct impact on the explosion-proof valve and avoiding abnormal opening and closing of the valve port due to foreign object interference. Furthermore, the mesh structure can provide auxiliary support to the core in the early stages of thermal runaway.

[0023] As an optional technical solution of this application, the mesh structure includes an outer ring, a middle ring group, and an inner ring group. The outer ring is disposed around the periphery of the perforation or extends protruding from the inner wall of the perforation towards the center of the perforation. The middle ring group is opposite to the perforation in the thickness direction and includes a plurality of concentric and sequentially surrounding middle rings. The outermost middle ring is connected to the outer ring through a plurality of first connecting portions, and the middle rings are connected to each other through the first connecting portions. The inner ring group is opposite to the perforation in the thickness direction and includes a plurality of concentric and sequentially surrounding inner rings or semi-rings. The inner ring group is connected to the innermost middle ring through a plurality of second connecting portions. Wherein, in the ring direction of the middle ring, the size of the second connecting portion is smaller than the size of the first connecting portion; and / or, in the thickness direction of the plastic body, the size of the second connecting portion is smaller than the size of the first connecting portion; and / or, on the plane, the projected area of ​​the inner ring group is smaller than the projected area of ​​the perforation.

[0024] In the above technical solution, the lower plastic layer is designed with a multi-layered mesh structure consisting of an outer ring, a middle ring group, and an inner ring group. The connection strength of the second connection part of the inner ring group is weaker than that of the first connection part of the outer ring group, achieving a controllable fracture pressure relief mechanism. When the core of the energy storage device experiences a sudden increase in thermal runaway pressure, the weakest part, the inner ring group, will be preferentially broken due to the weaker connection strength of the second connection part. This instantly opens a large, unobstructed pressure relief channel directly in front of the explosion-proof valve, avoiding the limitation of instantaneous venting volume caused by the lower plastic layer in traditional structures, thus improving the thermal safety performance of the energy storage device.

[0025] As an optional technical solution of this application, the inner ring assembly includes a first component and a second component arranged symmetrically. Both the first and second components include multiple concentric and sequentially surrounding semi-rings. The first and second components are connected by a second connecting portion, and each is connected to the innermost intermediate ring by the second connecting portion. The total width of all the second connecting portions is smaller than the opening size of the perforation in the length direction.

[0026] In the above technical solution, the lower plastic layer is specifically designed as two symmetrical components within the inner ring assembly. Furthermore, the total width of all second connecting parts along the length of the plastic body is limited to less than the opening size of the explosion-proof valve. This dual design, based on structural symmetry and geometric dimensions, ensures reliable fracture of the inner layer structure and smooth gas discharge. In the event of thermal runaway of the energy storage device's core, the symmetrical design guarantees balanced stress and synchronous fracture of the two symmetrical components. The limitation on the total width prevents the broken components from becoming stuck at the explosion-proof valve's opening, thus avoiding secondary blockage and ensuring the unobstructed pressure relief channel, thereby improving the thermal safety performance of the energy storage device.

[0027] As an optional technical solution of this application, the reinforcing member is a metal structural member or a ceramic structural member, and the surface of the reinforcing member is provided with an electrically insulating layer. In the above technical solution, the lower plastic section provides a high-temperature resistant redundant safety structure by adding a surface-insulating metal or ceramic reinforcing member. When the core of the energy storage device undergoes thermal runaway, causing the plastic portion of the lower plastic section to soften or melt, the reinforcing member can still maintain rigidity and continue to prevent the core from moving towards the explosion-proof valve area. This avoids the core from blocking the valve port of the explosion-proof valve due to loss of support in the later stages of thermal runaway, thereby improving the thermal safety performance of the energy storage device.

[0028] As an optional technical solution of this application, the reinforcing member is a hollow frame and includes at least one peripheral wall. On a plane perpendicular to the thickness direction of the plastic body, the peripheral wall is located between the mesh structure of the explosion-proof valve area and the first boss. The peripheral wall is provided with a fourth through hole, which is correspondingly connected to the first through hole on the first boss.

[0029] In the aforementioned technical solution, the lower plastic component is designed as a hollow frame structure with a fourth through hole, and its peripheral wall is positioned at a specific location, seamlessly integrating the high-strength reinforcement into the exhaust path. In the event of thermal runaway of the energy storage device's core, this design ensures the necessary mechanical support strength for the reinforcement while maintaining connectivity between the second and first exhaust channels through the fourth through hole. This avoids negatively impacting the existing efficient exhaust system due to the reinforcement's introduction, thereby improving the thermal safety performance of the energy storage device.

[0030] As an optional technical solution of this application, the side edge of the plastic body is provided with a chamfer.

[0031] In the above technical solution, the lower plastic body has a chamfered edge on the side, which optimizes the sharp edge into a smooth transition. On the one hand, under the high voltage environment of the energy storage device, the smooth chamfered edge can smooth the electric field distribution and eliminate the local electric field concentration caused by the "electric field tip effect", thereby effectively preventing the air from being ionized and broken down, reducing the risk of high voltage conduction short circuit between the core and the top cover, and improving the electrical safety and reliability of the energy storage device. On the other hand, the smooth transition can guide the gas flow field to be smoother, reduce the eddies and flow resistance caused by the right-angle step, thereby improving the overall exhaust efficiency.

[0032] Secondly, this application provides a top cover assembly. The top cover assembly includes a top cover and a lower plastic layer as described in any of the above embodiments. In the thickness direction of the top cover, the top cover includes a first surface and a second surface facing away from each other. The lower plastic layer is mounted on the second surface of the top cover.

[0033] In the top cover assembly of the above technical solution, the lower plastic body has a first protrusion group located on both sides of the explosion-proof valve area at the bottom of the plastic body, which constitutes a blocking and protection structure for the explosion-proof valve area. When the core of the energy storage device experiences thermal runaway, the first protrusion can effectively block the core that arches upward and towards the middle due to gas generation, preventing the core from directly impacting and blocking the exhaust area below the explosion-proof valve, thereby ensuring that the gas can be discharged smoothly and avoiding the shell rupture or even explosion of the energy storage device caused by poor exhaust, thus improving the thermal safety performance of the energy storage device.

[0034] As an optional technical solution of this application, the length of the plastic body is configured to be the same as the length of the top cover; or, the length of the plastic body is configured to be less than the length of the top cover, and the distance between the end of the plastic body and the corresponding end of the top cover in the length direction of the plastic body is 0mm to 1mm.

[0035] In the above technical solution, the top cover assembly ensures that the edge of the lower plastic is almost flush with the edge of the top cover by limiting the length of the lower plastic to be the same as or only slightly different from the length of the top cover. In this way, the protruding step caused by the lower plastic being too short can be eliminated to the greatest extent, avoiding the risk of short circuit between the core and the top cover under high pressure at this step, thereby preventing thermal runaway caused by internal insulation failure and improving the thermal safety performance of the energy storage device.

[0036] Thirdly, this application provides an energy storage device. The energy storage device includes a housing, a top cover assembly as described in any of the above embodiments, and a winding core. The top cover assembly is used to seal the opening of the housing, and the winding core is housed within the housing.

[0037] In the energy storage device described above, the lower plastic of the top cover assembly constructs a blocking and protective structure for the explosion-proof valve area by setting a first protrusion group on both sides of the explosion-proof valve area at the bottom of the plastic body. When the core of the energy storage device experiences thermal runaway, the first protrusion can effectively block the core from arching upwards and towards the middle due to gas generation, preventing the core from directly impacting and blocking the exhaust area below the explosion-proof valve, thereby ensuring that the gas can be discharged smoothly and avoiding the shell rupture or even explosion of the energy storage device caused by poor exhaust, thus improving the thermal safety performance of the energy storage device.

[0038] Fourthly, this application provides an electrical appliance. The electrical appliance includes the energy storage device described in any of the above embodiments.

[0039] In the electrical equipment of the above-mentioned technical solution, the lower plastic of the top cover assembly of the energy storage device constructs a blocking and protection structure for the explosion-proof valve area by setting a first protrusion group on both sides of the explosion-proof valve area at the bottom of the plastic body. When the core of the energy storage device experiences thermal runaway, the first protrusion can effectively block the core that arches upward and towards the middle due to gas generation, preventing the core from directly impacting and blocking the exhaust area below the explosion-proof valve, thereby ensuring that the gas can be discharged smoothly and avoiding the shell rupture or even explosion of the energy storage device caused by poor exhaust, thus improving the thermal safety performance of the energy storage device.

[0040] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0041] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0042] Figure 1 This is a three-dimensional assembly diagram of the plastic material from one perspective of some embodiments of this application.

[0043] Figure 2 for Figure 1 The diagram shows a three-dimensional assembly of the lower plastic material from another perspective.

[0044] Figure 3 for Figure 1 The diagram shown is a three-dimensional assembly diagram of the lower plastic from another perspective.

[0045] Figure 4 for Figure 1The diagram shown is a three-dimensional exploded view of the lower plastic.

[0046] Figure 5 for Figure 2 The diagram shown is a three-dimensional exploded view of the lower plastic.

[0047] Figure 6 for Figure 3 The diagram shown is a three-dimensional exploded view of the lower plastic.

[0048] Figure 7 for Figure 5 An enlarged schematic diagram of point VII on the lower plastic sheet;

[0049] Figure 8 for Figure 6 An enlarged schematic diagram of section VIII of the lower plastic shown;

[0050] Figure 9 for Figure 1 The bottom view of the plastic shown;

[0051] Figure 10 for Figure 9 An enlarged schematic diagram of the X-shaped part of the lower plastic shown;

[0052] Figure 11 This is a three-dimensional assembly diagram of the top cover assembly according to some embodiments of this application;

[0053] Figure 12 for Figure 11 An exploded perspective view of the top cover assembly shown;

[0054] Figure 13 This is a three-dimensional assembly diagram of a battery cell according to some embodiments of this application;

[0055] Figure 14 for Figure 13 The diagram shows a three-dimensional exploded view of a single battery cell;

[0056] Figure 15 This is a three-dimensional structural diagram of a battery pack according to some embodiments of this application;

[0057] Figure 16 This is a schematic diagram of the planar structure of an electrical device according to some embodiments of this application.

[0058] The reference numerals in the detailed embodiments are as follows:

[0059] Electrical equipment 10000; Energy storage device 1000; Battery cell 1001; Battery pack 1003; Battery box 10031; Box body 10033; Cover 10035; High-voltage cable 2000; First power conversion device 3000; Second power conversion device 4000; Top cover assembly 100; Housing 300; Core 500;

[0060] Lower plastic 10, plastic body 11, perforation 110, first side 111, second side 113, explosion-proof valve area 115, chamfer 117, end of plastic body 119, boss 13, first boss group 13a, first boss 131, first sidewall 1311, second sidewall 1313, third sidewall 1315, first through hole 1317, first exhaust channel 1319, second boss group 13b, second boss 133, first outer wall 1331, second outer wall 1333, third outer wall 1 335, second through hole 1337, second exhaust channel 1339, protrusion 1332, connecting surface 1334, third through hole 1336, third exhaust channel 1338, mesh structure 15, outer ring 151, intermediate ring group 153, intermediate ring 1531, first connecting part 155, inner ring group 157, inner ring 1571, half ring 1573, first component 1575, second component 1577, second connecting part 159, reinforcing member 17, peripheral wall 171, fourth through hole 1710;

[0061] Top cover 30, first surface 31, second surface 33, corresponding end 35 of top cover; explosion-proof valve 50; pole post 70;

[0062] Length direction X, width direction Y, thickness direction Z. Detailed Implementation

[0063] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0064] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0065] In this document, the term "implementation" means that a specific feature, structure, or characteristic described in connection with an implementation may be included in at least one implementation of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same implementation, nor is it a separate or alternative implementation mutually exclusive with other implementations. It will be explicitly and implicitly understood by those skilled in the art that the implementations described herein can be combined with other implementations.

[0066] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, the simultaneous existence of mounting protrusions and mounting holes, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following associated objects have an "or" relationship.

[0067] In the description of the embodiments of this application, the technical terms "center", "first", "second", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "level", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0068] In the description of the embodiments of this application, unless otherwise explicitly specified and limited, the technical terms such as "installation", "connection", "linking", and "fixing" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components.

[0069] Currently used high-capacity batteries generally suffer from poor venting pathways in their lower plastic casings. Especially after thermal runaway, the internal coil (JR) expands and is carried upwards by rising airflow, easily blocking the battery's venting channels. Current batteries lack effective measures to prevent this blockage, posing a safety hazard of battery casing rupture or even explosion due to poor venting. To address this issue, this application provides a lower plastic casing 10 (… Figures 1 to 10 As shown), top cover assembly 100 ( Figure 11 and Figure 12 As shown), energy storage device 1000 ( Figures 13 to 15 (as shown) and electrical equipment 10000 ( Figure 16 (As shown).

[0070] Please refer to sections 1 to 2. Figure 3 , Figures 13 to 15 This application provides a lower plastic 10 for an energy storage device 1000. Please refer to the following: Figures 4 to 6The lower plastic body 10 includes a plastic body 11, a plurality of bosses 13, and a reinforcing member 17. The plastic body 11 includes a first side 111 and a second side 113 opposite to each other in the thickness direction Z, and has an explosion-proof valve region 115 corresponding to the explosion-proof valve 50 of the energy storage device 1000. The plurality of bosses 13 are disposed on the second side 113 of the plastic body 11. The plurality of bosses 13 include a first boss group 13a located on both sides of the explosion-proof valve region 115 in the length direction X of the plastic body 11. The first boss group 13a is configured to prevent the core 500 of the energy storage device 1000 from moving towards the explosion-proof valve region 115 during thermal runaway expansion. The reinforcing member 17 is disposed on the second side 113 of the plastic body 11 and corresponds to the explosion-proof valve region 115. The reinforcing member 17 is connected to the plastic body 11 and / or the first boss group 13a. The reinforcing member 17 is configured to prevent the core 500 from moving toward the explosion-proof valve area 115 when the core 500 expands in thermal runaway.

[0071] The plastic body 11 is the basic component in the lower plastic 10 used for structural support and electrical insulation. Its material includes, but is not limited to, engineering plastics such as polypropylene (PP) and polyphenylene sulfide (PPS) that are resistant to electrolytes and have good insulating properties. The first side 111 of the plastic body 11 is configured as a mounting surface for contact with the top cover 30 of the energy storage device 1000. Figure 12 (As shown) Connection; the second side 113 faces the core 500. The explosion-proof valve area 115 is a predefined local area on the plastic body 11, which is designed in position and area to correspond to the explosion-proof valve 50 of the energy storage device 1000.

[0072] The boss 13 is a protruding structure in the lower plastic body 10 that extends from the second side 113 of the plastic body 11 along the thickness direction Z of the plastic body 11 away from the plastic body 11. In one example, the boss 13 is integrally formed with the plastic body 11 by injection molding; in another example, the boss 13 is connected to the plastic body 11 by a connector (not shown). The boss 13 can improve structural rigidity, form a gap with the surface of the core 500 to construct an exhaust channel, and prevent the displacement of the core 500 in the event of thermal runaway. The first boss group 13a is a group of bosses 13 distributed on both sides of the explosion-proof valve region 115 along the length direction X of the plastic body 11. This group of bosses 13 can be symmetrically distributed about the axis of the explosion-proof valve region 115 in the width direction Y of the plastic body 11, or asymmetrically distributed about the axis of the explosion-proof valve region 115. During operation, when thermal runaway occurs in the core 500, the core 500 will expand violently due to internal gas generation, arching upwards and in the middle. The first boss group 13a directly bears and blocks the movement of the core 500 toward the explosion-proof valve area 115, thereby physically isolating the core 500 from direct contact with the space directly below the explosion-proof valve 50, thus preserving a channel for gas discharge. The boss 13 includes a first boss 131 constituting the first boss group 13a.

[0073] The reinforcing member 17 can be an independent metal structural component, made of materials such as aluminum or stainless steel. It can also be an independent ceramic structural component. The reinforcing member 17 is fixed to the explosion-proof valve area 115 of the plastic body 11 by means of snap-fit, insert injection molding, or bonding. The surface of the reinforcing member 17 is covered with an electrically insulating layer through processes such as anodizing or ceramic spraying to prevent electrical contact with the core 500. During operation, if the core 500 experiences thermal runaway leading to a high temperature, the plastic body 11 may soften or melt and lose strength. At this time, the metal reinforcing member 17, due to its high melting point and high strength, can maintain structural integrity, acting as a mechanical barrier to prevent the core 500 from breaking through the softened plastic and blocking the explosion-proof valve 50.

[0074] In the above technical solution, the lower plastic 10 constructs a blocking and protective structure for the explosion-proof valve area 115 by setting first protrusion groups 13a on both sides of the explosion-proof valve area 115 at the bottom of the plastic body 11. When the core 500 experiences thermal runaway, the first protrusions 131 can effectively block the core 500 from arching upwards and towards the center due to gas generation, preventing the core 500 from directly impacting and blocking the exhaust area below the explosion-proof valve 50, thereby ensuring that the gas can be discharged smoothly and avoiding the rupture or even explosion of the housing 300 of the energy storage device 1000 caused by poor exhaust, thus improving the thermal safety performance of the energy storage device 1000. Furthermore, the lower plastic 10 provides a high-temperature resistant redundant safety structure by setting surface-insulated metal and / or ceramic reinforcing members 17. When the plastic portion of the lower plastic 10 softens or melts due to thermal runaway of the core 500, the reinforcing member 17 can still maintain rigidity and continue to prevent the core 500 from moving toward the explosion-proof valve area 115. This avoids the core 500 from blocking the valve port of the explosion-proof valve 50 due to loss of support in the later stages of thermal runaway, and further improves the thermal safety performance of the energy storage device 1000.

[0075] Please refer to the following: Figures 5 to 8 As an optional technical solution of this application, the first boss group 13a includes a first boss 131. The first boss 131 includes a first sidewall 1311 and a second sidewall 1313 that are opposite to each other in the length direction X of the plastic body 11, and a third sidewall 1315 that connects the first sidewall 1311 and the second sidewall 1313. The third sidewall 1315 is disposed opposite to the plastic body 11 in the thickness direction Z of the plastic body 11. At least two of the first sidewall 1311, the second sidewall 1313 and the third sidewall 1315 are provided with a first through hole 1317 to form a first exhaust channel 1319.

[0076] The first sidewall 1311 and the second sidewall 1313 are two opposing sidewalls of the first boss 131 along the longitudinal direction X of the plastic body 11. The third sidewall 1315 is the sidewall of the first boss 131 opposite to the plastic body 11 along the thickness direction Z of the plastic body 11. The first through hole 1317 is a hole penetrating through the sidewall of the first boss 131. The first through hole 1317 may be provided on at least two of the first sidewall 1311, the second sidewall 1313, and the third sidewall 1315: the first sidewall 1311 and the second sidewall 1313 may have the first through hole 1317; or, the first sidewall 1311 and the third sidewall 1315 may have the first through hole 1317; or, the second sidewall 1313 and the third sidewall 1315 may have the first through hole 1317; or, all three sidewalls may have the first through hole 1317. At least two of the first sidewall 1311, the second sidewall 1313, and the third sidewall 1315 are provided with first through holes 1317, transforming the originally closed first boss 131 into a multi-channel structure. These first through holes 1317, distributed at different positions on the first boss 131, cooperate with each other to form a multi-path exhaust network inside the first boss 131 and in the surrounding space.

[0077] In the above technical solution, first through holes 1317 are opened on multiple side walls of the first boss 131, transforming the solid boss 131 used to block the core 500 into a porous structure that also has a flow guiding function. In the event of thermal runaway of the core 500, gas can enter and pass through from multiple directions (e.g., left and right, and below) of the boss 131, increasing the channels for gas flow and thereby improving the efficiency of gas collection and discharge from the inside of the core 500 to the explosion-proof valve area 115. This avoids pressure accumulation caused by local airflow obstruction and improves the thermal safety performance of the energy storage device 1000.

[0078] Please refer to the following: Figure 7 and Figure 8 As an optional technical solution of this application, when a first through hole 1317 is provided on the first sidewall 1311 and the second sidewall 1313 to form a first exhaust channel 1319, the first through hole 1317 on the first sidewall 1311 is aligned with the first through hole 1317 on the second sidewall 1313.

[0079] "Alignment" means that the central axis of the first through hole 1317 on the first sidewall 1311 and the central axis of the first through hole 1317 on the second sidewall 1313 are on a straight line or approximately on a straight line, allowing airflow to pass directly through the boss 131 with minimal turning and resistance. This alignment design is achieved during injection molding by optimizing the mold structure. During operation, the gas can pass through the boss 131 in a near-straight line, forming a low-resistance airflow path through the boss 131.

[0080] In the above technical solution, the lower plastic 10 forms a low-resistance, straight airflow channel through the boss 131 by aligning the first through holes 1317 on the opposite side walls of the first boss group 13a. In the event of thermal runaway of the core 500, the gas can pass through the boss 131 more directly and smoothly, reducing turbulence and pressure loss during gas passage, thereby optimizing exhaust efficiency and avoiding the impact of excessive flow resistance on the overall pressure relief rate. This further enhances the thermal safety performance of the energy storage device 1000.

[0081] Please refer to the following: Figure 5 and Figure 6 As an optional technical solution of this application, the plurality of bosses 13 further include a second boss group 13b located on opposite sides of the plastic body 11 along the length direction X. Along the length direction X, the second boss group 13b is closer to the end 119 of the plastic body than the first boss group 13a. The second boss group 13b is configured to prevent the core 500 from moving towards the plastic body 11 during thermal runaway expansion. The bosses 13 also include a second boss 133 constituting the second boss group 13b.

[0082] The second boss group 13b is a group of bosses 13 located on both sides of the plastic body 11 along the length direction X. In the thickness direction Z, the height of the second boss 133 is equal to the height of the first boss 131, or the height of the second boss 133 is less than the height of the first boss 131; or the height of the second boss 133 is greater than the height of the first boss 131.

[0083] Please combine Figure 13 and Figure 14 In the above technical solution, the lower plastic 10 constructs a lateral blocking and protection structure by adding a second protrusion group 13b on both sides of the plastic body 11. When the core 500 experiences thermal runaway, the core 500 will not only arch towards the explosion-proof valve area 115 in the middle, but also expand in all directions. The second protrusion 133 can effectively limit the excessive expansion and movement of the core 500 towards the side wall of the housing 300 of the energy storage device 1000, preventing the core 500 from being squeezed and damaged by the housing 300 or the side of the lower plastic 10, thus causing an internal short circuit. It also constrains the expansion shape of the core 500 within the area jointly defined by the first protrusion group 13a and the second protrusion group 13b. At the same time, it helps to maintain the shape of the first exhaust channel 1319 of the explosion-proof valve area 115, thereby indirectly ensuring smooth exhaust and improving the thermal safety performance of the energy storage device 1000.

[0084] Please see Figure 5 and Figure 6As an optional technical solution of this application, the second boss assembly 13b includes a second boss 133. The second boss 133 includes a first outer wall 1331 and a second outer wall 1333 opposite to each other in the length direction X of the plastic body 11, and a third outer wall 1335 connecting the first outer wall 1331 and the second outer wall 1333. The third outer wall 1335 is disposed opposite to the plastic body 11 in the thickness direction Z of the plastic body 11. At least two of the first outer wall 1331, the second outer wall 1333 and the third outer wall 1335 are provided with a second through hole 1337 to form a second exhaust channel 1339.

[0085] The first outer wall 1331 and the second outer wall 1333 are two opposite sidewalls of the second boss 133 in the longitudinal direction X of the plastic body 11. The third outer wall 1335 is the sidewall of the second boss 133 opposite to the plastic body 11 in the thickness direction Z of the plastic body 11. The second through hole 1337 is a hole that penetrates the sidewall of the second boss 133. The second through hole 1337 is provided on at least two of the first outer wall 1331, the second outer wall 1333 and the third outer wall 1335, which can be: the first outer wall 1331 and the second outer wall 1333 are provided with the second through hole 1337; or, the first outer wall 1331 and the third outer wall 1335 are provided with the second through hole 1337; or, the second outer wall 1333 and the third outer wall 1335 are provided with the second through hole 1337; or, the first outer wall 1331, the second outer wall 1333 and the third outer wall 1335 are all provided with the second through hole 1337. At least two of the first outer wall 1331, the second outer wall 1333, and the third outer wall 1335 are provided with second through holes 1337, transforming the originally closed second boss 133 into a porous structure. These second through holes 1337, distributed at different positions on the second boss 133, cooperate with each other to form a multi-path exhaust network inside and around the second boss 133. Specifically, when the first outer wall 1331 and the second outer wall 1333 are provided with first through holes 1317 to form exhaust channels, the second through holes 1337 on the first outer wall 1331 are aligned with the second through holes 1337 on the second outer wall 1333. The explanation of "alignment" is as above.

[0086] In the above technical solution, a second through hole 1337 is opened on the side wall of the second boss 133, so that the lateral blocking and protection structure also has efficient flow guiding capability. When the core 500 thermally runs away, the gas gathered from the lateral exhaust gap can pass through the second boss group 13b without obstruction, thus forming an efficient second exhaust channel 1339. The second exhaust channel 1339 is connected to the first exhaust channel 1319, thereby improving the entire exhaust network, avoiding the increase of exhaust burden on the first exhaust channel 1319 due to insufficient lateral exhaust, and improving the thermal safety performance of the energy storage device 1000.

[0087] Please see Figure 5 or Figure 9 As an optional technical solution of this application, in the length direction X of the plastic body 11, the second boss group 13b is recessed inward by 2mm to 10mm relative to the end 119 of the plastic body. Specifically, in the length direction X of the plastic body 11, the first outer wall 1331 is farther away from the explosion-proof valve region 115 than the second outer wall 1333, and the first outer wall 1331 is recessed by 2mm to 10mm relative to the end 119 of the plastic body towards the explosion-proof valve region 115.

[0088] "Inward retraction" refers to the distance D1 by which the outer edge of the second boss assembly 13b recedes from the end 119 (outer edge) of the plastic body 11 towards the center of the plastic body 11 in a plane perpendicular to the thickness direction Z of the plastic body 11. Specifically, this distance D1 can be any value among 2mm, 2.5mm, 3mm, 3.3mm, 3.8mm, 4.5mm, 4.8mm, 5.2mm, 5.7mm, 6.6mm, 7.9mm, 8.3mm, 8.8mm, 9.9mm, and 10mm, or any value between two adjacent values. When D1 < 2mm, the inward retraction distance is too small, and the resistance to gas flow is still relatively large, leading to gas accumulation in the edge area and local pressure buildup. When D1 > 10mm, the inward distance is too large, and the position of the second boss group 13b is too close to the center, which weakens the blocking and limiting effect of the second boss group 13b on the side expansion of the core 500. The core 500 may still have a large risk of squeezing and friction with the shell 300.

[0089] Therefore, by recessing the first outer wall 1331 of the second boss assembly 13b 2mm to 10mm towards the explosion-proof valve region 115 relative to the end 119 of the plastic body, the lower plastic 10 forms a preset lateral venting gap between the end 119 of the plastic body and the second boss 133. In the event of thermal runaway of the core 500, this lateral venting gap provides a low-resistance collection and upward channel for the gas generated in the electrolyte regions on both sides of the core 500, ensuring that this gas can be smoothly introduced into the upper venting network, avoiding the formation of flow dead zones at the edges and corners, which would lead to local pressure increases. This achieves balanced venting across the entire area, thereby improving the thermal safety performance of the energy storage device 1000.

[0090] Please refer to the following: Figure 5 and Figure 6As an optional technical solution of this application, the second protrusion 133 further includes a protrusion 1332, which is connected to or integral with at least one of the first outer wall 1331, the second outer wall 1333 and the third outer wall 1335. The protrusion 1332 is provided with a third through hole 1336 to form a third exhaust channel 1338. The protrusion 1332 is configured to be connected to the Mylar membrane of the energy storage device 1000.

[0091] In some embodiments, the protrusion 1332 includes a connecting surface 1334, which is closer to the end 119 of the plastic body than the first outer wall 1331 in the longitudinal direction X of the plastic body 11. The connecting surface 1334 is configured to connect to the Mylar membrane of the energy storage device 1000.

[0092] The protrusion 1332 is an additional structure provided in the boss 133 for fixing and positioning. In some embodiments, the protrusion 1332 is designed with a groove or bearing surface to place hot melt adhesive, which can be used to connect the Mylar membrane. In other embodiments, hot melt adhesive may not be provided, and the Mylar membrane may be directly fused to the connecting surface 1334. In addition, the protrusion 1332 can be integrally formed with at least one of the first outer wall 1331, the second outer wall 1333, and the third outer wall 1335 by injection molding, thereby ensuring the structural strength of the entire boss 133. The third through hole 1336 is a hole structure that penetrates the protrusion 1332. The third exhaust channel 1338 is a local airflow path formed by the third through hole 1336 and belongs to the hot melt adhesive fixing point.

[0093] In the above technical solution, the lower plastic 10 achieves the integration of mechanical fixation and gas flow functions of the Mylar membrane by connecting or integrating the protrusion 1332 used for connecting the Mylar membrane with the second boss 133 forming the second venting channel 1339, and opening a third through hole 1336 to form a third venting channel 1338. Furthermore, since the connecting surface 1334 is closer to the end 119 of the plastic body than the first outer wall 1331, a lateral venting gap is formed between the first outer wall 1331 and the end 119 of the plastic body. This avoids the formation of flow dead zones at the edges and corners, preventing local pressure increases. Simultaneously, compared to the absence of a lateral venting gap, the presence of the connecting surface 1334 ensures that the fixing points of the Mylar membrane remain unchanged, avoiding changes to the connection process of the Mylar membrane and saving costs.

[0094] Please refer to the following: Figure 4 , Figure 9 and Figure 10As an optional technical solution of this application, the plastic body 11 is provided with a perforation 110 and a mesh structure 15 in the explosion-proof valve area 115. The perforation 110 penetrates the first side 111 and the second side 113 of the plastic body 11. The mesh structure 15 is disposed on the second side 113 of the plastic body 11, or the mesh structure 15 is disposed within the perforation 110. Regardless of the placement of the mesh structure 15, in the plane perpendicular to the thickness direction Z of the plastic body 11, the projection of the mesh structure 15 covers the projection of the perforation 110, and the total opening area S1 of the mesh structure 15 accounts for 50% or more of the total area S of the mesh structure 15 (S1 / S≥50%).

[0095] The perforation 110 is a through hole opened in the plastic body 11 for installing and exposing the explosion-proof valve 50. The mesh structure 15 is a porous panel-like structure located directly below or inside the perforation 110, formed by connecting ribs. The mesh structure 15 and the plastic body 11 can be integrally molded by injection molding. The projection of the mesh structure 15 on the plane completely covers the projection of the perforation 110, ensuring that the gas discharged from the explosion-proof valve 50 must first pass through the mesh structure 15. By designing the width and spacing of the ribs, the total open area ratio of the mesh structure 15 can be controlled to exceed 50%, for example, it can reach any one of 50%, 55%, 58%, 60%, 75%, 68%, 71%, 75%, 77%, 80%, 85%, 88%, 90%, 95%, and 98%, or any value between any two adjacent values. If S1 / S < 50%, the solid ribs occupy most of the area, forming a serious flow bottleneck. When the gas flows through the narrow channel, the flow velocity increases, but the pressure loss (i.e., resistance) will increase exponentially. This can cause the internal pressure peak to rise abnormally when the core 500 is thermally runaway. The excessive internal pressure may exceed the tensile strength limit of the shell 300 material, causing the shell 300 to bulge, rupture or even explode before the explosion-proof valve 50 is opened normally, thus rendering the explosion-proof valve 50, the last safety measure, ineffective.

[0096] In the above technical solution, the lower plastic 10 creates a protective interface that combines excellent air permeability and necessary mechanical strength by setting a mesh structure 15 with a high opening ratio in the area directly opposite the explosion-proof valve 50. During thermal runaway of the core 500, the high porosity of the mesh structure 15 greatly reduces gas flow resistance, ensuring smooth venting. Simultaneously, the mesh shape of the mesh structure 15 effectively intercepts and supports solid particles carried by the gas, preventing particles from directly impacting the explosion-proof valve 50 and avoiding abnormal opening and closing of the valve port due to foreign object interference. Furthermore, the mesh structure 15 can provide auxiliary support to the core 500 in the early stages of thermal runaway.

[0097] Please refer to the following as well. Figure 4 , Figure 7 , Figure 9 and Figure 10As an optional technical solution of this application, the mesh structure 15 includes an outer ring 151, a middle ring group 153, and an inner ring group 157. The outer ring 151 is disposed around the periphery of the perforation 110 or extends protruding from the inner wall of the perforation 110 toward the center of the perforation 110. The middle ring group 153 is opposite to the perforation 110 in the thickness direction Z and includes a plurality of concentric and sequentially surrounding middle rings 1531. The outermost middle ring 1531 is connected to the outer ring 151 through a plurality of first connecting portions 155, and the middle rings 1531 are connected to each other through the first connecting portions 155. The inner ring group 157 is opposite to the perforation 110 in the thickness direction Z and includes a plurality of concentric and sequentially surrounding inner rings 1571 or half rings 1573. The inner ring group 157 is connected to the innermost middle ring 1531 through a plurality of second connecting portions 159. Specifically, in the circumferential direction of the intermediate ring 1531, the size of the second connecting portion 159 is smaller than the size of the first connecting portion 155; and / or, in the thickness direction Z of the plastic body 11, the size of the second connecting portion 159 is smaller than the size of the first connecting portion 155; and / or, in the plane, the projected area of ​​the inner ring group 157 is smaller than the projected area of ​​the perforation 110.

[0098] The outer ring 151 is the outermost annular frame in the mesh structure 15 that is connected to the plastic body 11. The intermediate ring group 153 is composed of multiple annular ribs arranged concentrically with successively decreasing inner dimensions. They are interconnected by the first connecting part 155 (i.e., connecting rib) and finally connected to the outer ring 151. The inner ring group 157 is composed of one or more complete rings or one or more half rings located at the center. The complete rings and / or half rings are connected to the innermost intermediate ring 1531 by the second connecting part 159 (i.e., a thinner or finer connecting rib). The size of the second connecting part 159 is smaller than that of the first connecting part 155, which can be: in the annular direction, the width of the second connecting part 159 is smaller than the width of the first connecting part 155; and / or, in the thickness direction Z of the plastic body 11, the thickness of the second connecting part 159 is smaller than the thickness of the first connecting part 155. At the same time, the overall area of ​​the inner ring group 157 is smaller than the area of ​​the perforation 110.

[0099] In the above technical solution, the lower plastic 10 is designed with a multi-layer mesh structure 15 consisting of an outer ring 151, a middle ring group 153, and an inner ring group 157. The connection strength of the second connecting part 159 of the inner ring group 157 is weaker than that of the first connecting part 155 of the outer ring group 157, thus achieving a controllable fracture pressure relief mechanism. When the thermal runaway gas pressure of the core 500 increases suddenly, the weakest part of the structure, the inner ring group 157, will be preferentially broken off due to the weaker connection strength of the second connecting part 159. This instantly opens a large, unobstructed pressure relief channel directly in front of the explosion-proof valve 50, avoiding the limitation of instantaneous exhaust volume caused by the lower plastic in traditional structures, and improving the thermal safety performance of the energy storage device 1000.

[0100] Please continue to refer to this as well. Figure 4 , Figure 9 and Figure 10 As an optional technical solution of this application, the inner ring assembly 157 includes a first component 1575 and a second component 1577 symmetrically arranged. Both the first component 1575 and the second component 1577 include multiple concentric and sequentially surrounding semi-rings 1573. The first component 1575 and the second component 1577 are connected by a second connecting portion 159, and are respectively connected to the innermost intermediate ring 1531 via the second connecting portion 159. The total width of all the second connecting portions 159 in the length direction X of the plastic body 11 is smaller than the opening size of the perforation 110 in the length direction X.

[0101] The first component 1575 and the second component 1577 are two symmetrical parts of the inner ring assembly 157, each component consisting of multiple concentric semi-racetrack-shaped ribs. The two components are connected by a second connecting part 159, and each component is also connected to the outer intermediate ring 1531 via the second connecting part 159. The sum of the dimensions of all the second connecting parts 159 in the longitudinal direction X of the plastic body 11 is controlled to be smaller than the inner dimension of the perforation 110 in that direction.

[0102] In the above technical solution, the lower plastic 10 specifically designs the inner ring assembly 157 as two symmetrical components, and limits the total size of all second connecting parts 159 to be smaller than the opening size of the explosion-proof valve 50. This ensures reliable fracture of the inner structure and smooth gas discharge from both structural symmetry and geometric dimensions. In the event of thermal runaway of the core 500, the symmetrical design ensures balanced stress and synchronous fracture of the two symmetrical components, while the limitation on the total width prevents the broken components from getting stuck in the valve port of the explosion-proof valve 50 and causing secondary blockage. This ensures that the pressure relief channel remains unobstructed and improves the thermal safety performance of the energy storage device 1000.

[0103] Please refer to the following: Figures 5 to 7 As an optional technical solution of this application, the reinforcing member 17 is a hollow frame and includes at least one peripheral wall 171. On a plane perpendicular to the thickness direction Z of the plastic body 11, the peripheral wall 171 is located between the mesh structure 15 of the explosion-proof valve area 115 and the first boss 131. The peripheral wall 171 is provided with a fourth through hole 1710, which is connected to the first through hole 1317 on the first boss 131.

[0104] "Hollow frame" refers to the reinforcing member 17 having a central cavity whose shape matches the explosion-proof valve area 115, such as an annular frame, more specifically a rectangular frame or a circular frame. The peripheral wall 171 of the reinforcing member 17 is the side wall constituting the frame. The fourth through hole 1710 is a hole penetrating the peripheral wall 171. The position of the fourth through hole 1710 is aligned with or connected to the first through hole 1317 on the first boss 131 (the first through hole 1317 on the first side wall 1311 and / or the first through hole 1317 on the second side wall 1313) in the longitudinal direction X of the plastic body 11. During operation, the airflow from the second exhaust passage 1339 on the side can pass through the first exhaust passage 1319 formed by the first through hole 1317 on the boss 131, and then smoothly pass through the peripheral wall 171 of the reinforcing member 17 through the fourth through hole 1710, enter the central cavity surrounded by the reinforcing member 17, and finally be discharged through the mesh structure 15 and the explosion-proof valve 50. In this way, it can be ensured that the introduction of the reinforcing member 17 will not block any existing exhaust path.

[0105] In the above technical solution, the lower plastic 10 integrates the high-strength reinforcing member 17 into the exhaust path by designing the reinforcing member 17 as a hollow frame structure with a fourth through hole 1710 and positioning its peripheral wall 171 in a specific location. In the event of thermal runaway of the core 500, this ensures both the required mechanical support strength of the reinforcing member 17 and the connectivity of the exhaust path through the fourth through hole 1710, avoiding any negative impact of the reinforcing member 17 on the original efficient exhaust path and improving the thermal safety performance of the energy storage device 1000.

[0106] Please see Figure 4 and Figure 6 As an optional technical solution of this application, the side edge of the plastic body 11 is provided with a chamfer 117.

[0107] Chamfer 117 is a beveled or rounded transition structure at the side edge of the plastic body 11, which can be formed during injection molding through mold design. This chamfer 117 replaces the original 90-degree right angle edge.

[0108] Please combine Figure 13 and Figure 14 In the above technical solution, the lower plastic 10 optimizes the sharp edge into a smooth transition by setting a chamfer 117 on the side edge of the plastic body 11. On the one hand, under the high voltage environment of the energy storage device 1000, the smooth chamfer 117 edge can smooth the electric field distribution, eliminate the local electric field concentration caused by the "electric field tip effect", thereby effectively preventing the air from being ionized and broken down, reducing the risk of high voltage conduction short circuit between the core 500 and the top cover 30, and improving the electrical safety and reliability of the energy storage device 1000. On the other hand, the smooth transition can guide the gas flow field to be smoother, reduce the eddies and flow resistance caused by the right-angle steps, thereby improving the overall exhaust efficiency.

[0109] Please refer to the following: Figure 11 and Figure 12 Secondly, this application provides a top cover assembly 100. The top cover assembly 100 includes a top cover 30 and a lower plastic 10 of any of the above embodiments. In the thickness direction Z of the top cover 30, the top cover 30 includes a first surface 31 and a second surface 33 facing away from each other. The lower plastic 10 is mounted on the second surface 33 of the top cover 30.

[0110] Please combine Figure 13 and Figure 14 The top cover assembly 100 is a component in the energy storage device 1000 used to seal the housing 300 and integrate key components such as the core 500. It typically includes a top cover 30, an explosion-proof valve 50 mounted on the top cover 30, an electrical connection pole 70, and a lower plastic component 10. The first side 31 (outer side) of the top cover 30 faces the external environment after the energy storage device 1000 is assembled, while the second side 33 (inner side) faces the interior of the energy storage device 1000. The lower plastic component 10, as a key insulation and thermal management component in the top cover assembly 100, is fixedly installed on the second side 33 of the top cover 30 by means of heat fusion, snap-fit, or adhesive bonding. By integrating the lower plastic component 10 with the top cover 30, the top cover assembly 100 achieves insulation isolation between the internal structure of the core 500 and the top cover 30, and constructs a complete thermal runaway venting and protection system.

[0111] Please combine Figures 5 to 8 In the top cover assembly 100 of the above technical solution, the lower plastic 10 constructs a blocking and protective structure for the explosion-proof valve area 115 by setting first protrusion groups 13a on both sides of the explosion-proof valve area 115 at the bottom of the plastic body 11. In the event of thermal runaway of the core 500, the first protrusions 131 can effectively block the core 500 from arching upwards and towards the center due to gas generation, preventing the core 500 from directly impacting and blocking the exhaust area below the explosion-proof valve 50, thereby ensuring that the gas can be discharged smoothly and avoiding the rupture or even explosion of the housing 300 of the energy storage device 1000 caused by poor exhaust, thus improving the thermal safety performance of the energy storage device 1000. At the same time, the lower plastic 10 provides a high-temperature resistant redundant safety structure by setting surface-insulated metal and / or ceramic reinforcing members 17. When the plastic portion of the lower plastic 10 softens or melts due to thermal runaway of the core 500, the reinforcing member 17 can still maintain rigidity and continue to prevent the core 500 from moving toward the explosion-proof valve area 115. This avoids the core 500 from blocking the valve port of the explosion-proof valve 50 due to loss of support in the later stages of thermal runaway, and further improves the thermal safety performance of the energy storage device 1000.

[0112] In some examples, the length of the plastic body 11 is configured to be the same as the length of the top cover 30. In other examples, please refer to... Figure 12The length of the plastic body 11 is configured to be less than the length of the top cover 30, and the distance D2 between the end 119 of the plastic body and the corresponding end 35 of the top cover in the length direction X of the plastic body 11 is 0 mm to 1 mm.

[0113] Specifically, the distance D2 can be any value among 0mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1.0mm, or any value between two adjacent values. When the distance D2 is greater than 1.0mm, the distance is too large, and a significant step will be formed between the end 119 of the lower plastic 10 and the edge of the top cover 30. Under increased internal pressure of the core 500 (such as in the event of thermal runaway) or long-term vibration, the core 500 will expand and shift towards this step, and come into direct contact with the exposed, uninsulated edge of the metal top cover 30, causing a short circuit between the positive and negative electrodes through the top cover 30, instantly generating a huge current and heat, which may directly trigger thermal runaway.

[0114] In the above technical solution, the top cover assembly 100 ensures that the edge of the lower plastic 10 is almost flush with the edge of the top cover 30 by limiting the length of the lower plastic 10 to be the same as or only slightly different from the length of the top cover 30. In this way, the protruding step caused by the lower plastic 10 being too short can be eliminated to the greatest extent, avoiding the risk of short circuit between the core 500 and the top cover 30 under high pressure at this step, thereby preventing thermal runaway caused by internal insulation failure and improving the thermal safety performance of the energy storage device 1000.

[0115] Please see Figures 13 to 15 Thirdly, this application provides an energy storage device 1000. The energy storage device 1000 is a device capable of reversibly storing and releasing electrical energy. Specifically, the energy storage device 1000 can be a single battery cell 1001 (… Figure 13 and Figure 14 (As shown), it can also be a battery pack 1003 composed of one or more battery cells 1001 (as shown). Figure 15 (As shown).

[0116] Please see Figure 15When the energy storage device 1000 is a battery pack 1003 composed of multiple battery cells 1001, the battery pack 1003 includes battery cells 1001 and a battery box 10031. A battery cell 1001 is the smallest unit for storing and releasing electrical energy. The battery pack 1003 can store and release energy by connecting and controlling the battery cells 1001. Multiple battery cells 1001 can be connected in series, parallel, or in a hybrid configuration. A hybrid configuration means that multiple battery cells 1001 are connected in both series and parallel connections. Multiple battery cells 1001 can be directly connected in series, parallel, or in a hybrid configuration, and then the entire assembly of the multiple battery cells 1001 is housed within a carrier (e.g., the battery box 10031). The battery pack 1003 may also include other structures; for example, the battery pack 1003 may also include a busbar (not shown) for electrical connection between multiple battery cells 1001. It is understandable that the number of battery cells 1001 in the battery pack 1003 can be adjusted adaptively according to the application scenario and capacity.

[0117] Please see Figure 13 and Figure 14 The battery cell 1001 includes a top cover assembly 100, a housing 300, and a winding core 500. The housing 300 has an opening, and the top cover assembly 100 is installed in the housing 300 and closes the opening. The winding core 500 is housed within the housing 300. The housing 300 is a structure for housing the winding core 500. The cross-section of the housing 300 may be, but is not limited to, circular, elliptical, square, or other polygonal shapes. The material of the housing 300 includes, but is not limited to, metals and non-metals. Metals include aluminum, iron, steel, aluminum alloys, or iron alloys, while non-metals include, but are not limited to, plastics. In this application, the cross-section of the housing 300 is square, which facilitates integration into a square battery cell 1001. The material of the housing 300 is aluminum alloy, which, while ensuring rigidity, also makes the battery cell 1001 lighter and easier to transport.

[0118] The core 500 is the core structure in the battery cell 1001 that converts electrical energy into chemical energy through a chemical reaction for charging and discharging. The core 500 is generally made by winding electrode components onto a mandrel. The electrode components mainly include a negative electrode sheet, a positive electrode sheet, and a separator. In one possible design, the negative electrode sheet, separator, and positive electrode sheet are sequentially stacked and attached to the mandrel by adhesive or heat fusion, and then wound to form the core 500. After formation, the core 500 has gaps through which electrolyte can enter. The electrolyte is used to wet the core 500, ensuring that ions can move freely during charging and discharging. The electrolyte includes, but is not limited to, lithium salts, organic solvents, and additives. The negative electrode sheet includes a negative current collector (e.g., copper foil) and a layer of negative active material (e.g., carbon or silicon) coated on the surface of the negative current collector. The positive electrode includes a positive current collector (e.g., aluminum foil) and a layer of positive active material (e.g., ternary material, lithium iron phosphate, or lithium cobalt oxide) coated on the surface of the positive current collector. A separator is located between adjacent negative and positive electrodes to separate them.

[0119] The battery box 10031 is a structure for holding individual battery cells 1001. The cross-section of the battery box 10031 may be, but is not limited to, circular, elliptical, square, or other polygonal shapes. The material of the battery box 10031 includes, but is not limited to, metal or non-metal. Metals include aluminum, iron, steel, aluminum alloys, or iron alloys, while non-metals include, but are not limited to, plastics. In this application, the cross-section of the battery box 10031 is rectangular. The material of the battery box 10031 is aluminum alloy, which, while ensuring strength, also makes the battery pack 1003 lighter and easier to transport.

[0120] The battery box 10031 includes a box body 10033 and a cover 10035. The box body 10033 and the cover 10035 are combined to form a receiving cavity, in which a battery cell 1001 is received. The box body 10033 is the component in the battery box 10031 that loads and supports the battery cell 1001. One end of the box body 10033 is closed, and the other end has an opening for the battery cell 1001 to be inserted into the receiving cavity. The cover 10035 is the component in the battery box 10031 that covers the opening. The connection between the box body 10033 and the cover 10035 can be detachable or non-detachable. Detachable connections include, but are not limited to, screw connections, snap-fit ​​connections, or a combination of screw connections and snap-fit ​​connections. Non-detachable connections include, but are not limited to, glued connections, welded connections, or a combination of glued connections and welded connections. In this application, the box body 10033 and the cover 10035 are detachably connected.

[0121] When the battery box 10031 includes a box body 10033 and a cover 10035, the battery box 10031 may not be made of a single material. For example, the box body 10033 and the cover 10035 may be made of the same material, aluminum alloy. The battery box 10031 may also have different components made of different materials. For example, the box body 10033 may be made of metal, while the cover 10035 may be made of plastic. Of course, the materials of the box body 10033 and the cover 10035 may also be combinations of other different materials, which will not be listed here.

[0122] In the energy storage device 1000 described above, the lower plastic 10 of the top cover assembly 100 constructs a blocking and protective structure for the explosion-proof valve area 115 by setting first protrusion groups 13a on both sides of the explosion-proof valve area 115 at the bottom of the plastic body 11. In the event of thermal runaway of the core 500, the first protrusions 131 can effectively block the core 500 from arching upwards and towards the center due to gas generation, preventing the core 500 from directly impacting and blocking the exhaust area below the explosion-proof valve 50, thereby ensuring that the gas can be discharged smoothly and avoiding the rupture or even explosion of the housing 300 of the energy storage device 1000 caused by poor exhaust, thus improving the thermal safety performance of the energy storage device 1000. At the same time, the lower plastic 10 provides a high-temperature resistant redundant safety structure by setting surface-insulated metal and / or ceramic reinforcing members 17. When the plastic portion of the lower plastic 10 softens or melts due to thermal runaway of the core 500, the reinforcing member 17 can still maintain rigidity and continue to prevent the core 500 from moving toward the explosion-proof valve area 115. This avoids the core 500 from blocking the valve port of the explosion-proof valve 50 due to loss of support in the later stages of thermal runaway, and further improves the thermal safety performance of the energy storage device 1000.

[0123] Please see Figure 16 , Figure 16 This is a schematic diagram of the structure of an electrical device 10000 according to an embodiment of this application, and this application Figure 16 The implementation method is 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.

[0124] Fourthly, this application provides an electrical device 10000. The electrical device 10000 includes a high-voltage cable 2000, a first power conversion device 3000, a second power conversion device 4000, and an energy storage device 1000 according to any embodiment provided in this application. In some embodiments of the power generation scenario, the second power conversion device 4000 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 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... The device is always connected to the high-voltage cable. Under normal power generation conditions, the power output of the wind power conversion device is supplied to the power consumption side of the distribution network through 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 to reduce wind and solar curtailment rates and improve the problem of new energy power consumption. When the power load is high, the power grid issues an instruction to transmit the power stored in the energy storage device 1000 together with the high-voltage cable 2000 in grid-connected mode to supply power 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 role of the power grid, promoting peak shaving and valley filling, and alleviating the power supply pressure of the power grid.

[0125] In some embodiments on the distribution network side, the first power conversion device 3000 can be a photovoltaic power conversion device. The energy storage device 1000 is connected to the high-voltage cable 2000 and installed downstream of the high-voltage cable 2000 between the user load and the user load. The electrical energy output by 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 2000 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.

[0126] Optionally, the first power conversion device 3000 may include, but is not limited to, a wind power conversion device, and the second power conversion device 4000 may include, but is not limited to, a photovoltaic power conversion device. The first power conversion device 3000 and the second power conversion device 4000 can convert at least one of solar energy, light energy, wind energy, thermal energy, tidal energy, biomass energy and mechanical energy into electrical energy.

[0127] In the above-mentioned electrical equipment 10000, the lower plastic 10 of the top cover assembly 100 of the energy storage device 100 constructs a blocking and protective structure for the explosion-proof valve area 115 by setting first protrusion groups 13a on both sides of the explosion-proof valve area 115 at the bottom of the plastic body 11. In the event of thermal runaway of the core 500, the first protrusions 131 can effectively block the core 500 from arching upward and towards the middle due to gas generation, preventing the core 500 from directly impacting and blocking the exhaust area below the explosion-proof valve 50, thereby ensuring that the gas can be discharged smoothly and avoiding the rupture or even explosion of the housing 300 of the energy storage device 1000 caused by poor exhaust, thus improving the thermal safety performance of the energy storage device 1000. At the same time, the lower plastic 10 provides a high-temperature resistant redundant safety structure by setting surface-insulated metal and / or ceramic reinforcing members 17. When the plastic portion of the lower plastic 10 softens or melts due to thermal runaway of the core 500, the reinforcing member 17 can still maintain rigidity and continue to prevent the core 500 from moving toward the explosion-proof valve area 115. This avoids the core 500 from blocking the valve port of the explosion-proof valve 50 due to loss of support in the later stages of thermal runaway, and further improves the thermal safety performance of the energy storage device 1000.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A type of plastic (10) for use in an energy storage device (1000), characterized in that, include: The plastic body (11) includes a first side (111) and a second side (113) opposite to each other in the thickness direction Z of the plastic body (11), and has an explosion-proof valve area (115) for corresponding to the explosion-proof valve (50) of the energy storage device (1000). The plastic body (11) has a mesh structure (15) in the explosion-proof valve area (115). Multiple bosses (13) are disposed on the second side (113) of the plastic body (11). The multiple bosses (13) include a first boss group (13a) located on opposite sides of the explosion-proof valve region (115) along the longitudinal direction X of the plastic body (11). The first boss group (13a) is configured to prevent the core (500) of the energy storage device (1000) from moving towards the explosion-proof valve region (115) during thermal runaway expansion. A reinforcing member (17) is disposed on the second side (113) of the plastic body (11) and corresponds to the explosion-proof valve area (115). The reinforcing member (17) is a hollow frame and includes at least one peripheral wall (171). On a plane perpendicular to the thickness direction of the plastic body (11), the peripheral wall (171) is located between the mesh structure (15) of the explosion-proof valve area (115) and the first boss (131). The reinforcing member (17) is connected to the plastic body (11) and / or the first boss group (13a). The reinforcing member (17) is configured to prevent the core (500) from moving toward the explosion-proof valve area (115) when the core (500) expands in thermal runaway.

2. The lower plastic (10) according to claim 1, characterized in that, The first boss assembly (13a) includes a first boss (131), which includes a first sidewall (1311) and a second sidewall (1313) opposite to each other in the length direction X of the plastic body (11), and a third sidewall (1315) connecting the first sidewall (1311) and the second sidewall (1313). The third sidewall (1315) is disposed opposite to the plastic body (11) in the thickness direction Z of the plastic body (11). At least two of the first sidewall (1311), the second sidewall (1313) and the third sidewall (1315) are provided with a first through hole (1317) to form a first exhaust channel (1319).

3. The lower plastic (10) according to claim 2, characterized in that, When a first through hole (1317) is provided on the first sidewall (1311) and the second sidewall (1313) to form a first exhaust channel (1319), the first through hole (1317) on the first sidewall (1311) is aligned with the first through hole (1317) on the second sidewall (1313).

4. The lower plastic (10) according to claim 1, characterized in that, The plurality of the bosses (13) also include a second boss group (13b) located on opposite sides in the length direction X of the plastic body (11), the second boss group (13b) being closer to the end (119) of the plastic body than the first boss group (13a) in the length direction X, the second boss group (13b) being configured to prevent the core (500) of the energy storage device (1000) from moving toward the plastic body (11) during thermal runaway expansion.

5. The lower plastic (10) according to claim 4, characterized in that, The second boss assembly (13b) includes a second boss (133), which includes a first outer wall (1331) and a second outer wall (1333) opposite to each other in the length direction X of the plastic body (11), and a third outer wall (1335) connecting the first outer wall (1331) and the second outer wall (1333). The third outer wall (1335) is disposed opposite to the plastic body (11) in the thickness direction Z of the plastic body (11). At least two of the first outer wall (1331), the second outer wall (1333) and the third outer wall (1335) are provided with a second through hole (1337) to form a second exhaust channel (1339).

6. The lower plastic (10) according to claim 5, characterized in that, Along the length direction X of the plastic body (11), the first outer wall (1331) is further away from the explosion-proof valve area (115) than the second outer wall (1333), and the first outer wall (1331) is recessed by 2 mm to 10 mm relative to the end (119) of the plastic body toward the explosion-proof valve area (115).

7. The lower plastic (10) according to claim 5, characterized in that, The second boss (133) also includes: The protrusion (1332) is connected to or integral with at least one of the first outer wall (1331), the second outer wall (1333) and the third outer wall (1335), the protrusion (1332) is provided with a third through hole (1336) to form a third exhaust channel (1338), and the protrusion (1332) is configured to be connected to the Mylar membrane of the energy storage device (1000).

8. The lower plastic (10) according to claim 7, characterized in that, The protrusion (1332) includes a connecting surface (1334) in the longitudinal direction X of the plastic body (11), the connecting surface (1334) being closer to the end (119) of the plastic body than the first outer wall (1331), and the connecting surface (1334) being configured to connect to the Mylar membrane of the energy storage device (1000).

9. The lower plastic (10) according to any one of claims 1-8, characterized in that, The plastic body (11) is further provided in the explosion-proof valve area (115) with: A perforation (110) is made through the first side (111) and the second side (113) of the plastic body (11). The mesh structure (15) is disposed on the second side (113) of the plastic body (11) or in the perforation (110). In the plane perpendicular to the thickness direction Z of the plastic body (11), the projection of the mesh structure (15) covers the projection of the perforation (110). The total opening area of ​​the mesh structure (15) accounts for 50% or more of the total area of ​​the mesh structure (15).

10. The lower plastic (10) according to claim 9, characterized in that, The mesh structure (15) includes: The outer ring (151) is disposed around the periphery of the perforation (110) or extends protruding from the inner wall of the perforation (110) toward the center of the perforation (110); An intermediate ring assembly (153) is opposite to the perforation (110) in the thickness direction Z and includes a plurality of concentric and sequentially surrounding intermediate rings (1531). The outermost intermediate ring (1531) is connected to the outer ring (151) through a plurality of first connecting parts (155), and the intermediate rings (1531) are connected to each other through the first connecting parts (155). The inner ring assembly (157) is opposite to the perforation (110) in the thickness direction Z and includes a plurality of concentric inner rings (1571) or semi-rings (1573) that surround the inner ring in sequence. The inner ring assembly (157) is connected to the innermost intermediate ring (1531) through a plurality of second connecting parts (159), wherein: In the circumferential direction of the intermediate ring (1531), the size of the second connecting portion (159) is smaller than the size of the first connecting portion (155); and / or, In the thickness direction Z of the plastic body (11), the size of the second connecting portion (159) is smaller than the size of the first connecting portion (155); and / or, On the plane, the projected area of ​​the inner ring group (157) is smaller than the projected area of ​​the perforation (110).

11. The lower plastic (10) according to claim 10, characterized in that, The inner ring assembly (157) includes a first component (1575) and a second component (1577) arranged symmetrically. Both the first component (1575) and the second component (1577) include a plurality of concentric and sequentially surrounding semi-rings (1573). The first component (1575) and the second component (1577) are connected by the second connecting part (159), and are respectively connected to the innermost intermediate ring (1531) by the second connecting part (159); The total width of all the second connecting portions (159) in the length direction X of the plastic body (11) is smaller than the opening size of the perforation (110) in the length direction.

12. The lower plastic (10) according to any one of claims 1-8, characterized in that, The reinforcing member (17) is a metal structural member or a ceramic structural member, and an electrical insulating layer is provided on the surface of the reinforcing member (17).

13. The lower plastic (10) according to claim 12, characterized in that, The peripheral wall (171) is provided with a fourth through hole (1710), which is connected to the first through hole (1317) on the first boss (131).

14. The lower plastic (10) according to any one of claims 1-8, characterized in that, The side edge of the plastic body (11) is provided with a chamfer (117).

15. A top cover assembly (100), characterized in that, include: The top cover (30) includes a first surface (31) and a second surface (33) facing away from each other in the thickness direction. and The lower plastic (10) according to any one of claims 1 to 14, wherein the lower plastic (10) is mounted on the second side (33) of the top cover (30).

16. The top cover assembly (100) according to claim 15, characterized in that, The length of the plastic body (11) is configured to be the same as the length of the top cover (30); or, The length of the plastic body (11) is configured to be less than the length of the top cover (30), and the distance between the end (119) of the plastic body and the corresponding end (35) of the top cover in the length direction of the plastic body (11) is 0 mm to 1 mm.

17. An energy storage device (1000), characterized in that, include: Housing (300); The top cover assembly (100) of claim 15 or 16, the top cover assembly (100) being used to seal the opening of the housing (300); and The core (500) is housed within the housing (300).

18. An electrical appliance (10000), characterized in that, Includes the energy storage device (1000) as described in claim 17.

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