Lower plastic, end cover component, energy storage apparatus and electrical device

Abstract

A lower plastic (10), an end cover component, an energy storage apparatus (1000) and an electrical device. The lower plastic (10) comprises a body (11), an anti-explosion counter (12), a first counter (13), a second counter (14), a first post boss (15) and a second post boss (16). A first surface (111), a second bottom wall (135), a third bottom wall (145), a fourth bottom wall (155) and a fifth bottom wall (165) of the lower plastic (10) each have a first surface roughness, and a second surface (112), a first bottom wall, a first top surface, a second top surface (131), a third top surface (141), a fourth top surface (151) and a fifth top surface (161) of the lower plastic (10) each have a second surface roughness, the first surface roughness being A, and the second surface roughness being B, satisfying: A < B.

Description

Lower plastic, end cover assembly, energy storage device and electrical equipment

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on March 6, 2024, with application number 202410253859.7 and application name “Lower plastic, end cover assembly, energy storage device and electrical equipment”, all contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of energy storage technology, and in particular to a lower plastic, an end cover assembly, an energy storage device and an electrical device. Background Art

[0003] Secondary batteries, also known as rechargeable batteries or storage batteries, are batteries that can be recharged after discharge to activate the active materials and continue to be used. The recyclable nature of secondary batteries has made them a key power source for electrical devices. As demand for secondary batteries increases, so too does the demand for their performance, particularly regarding energy density per unit volume. The thickness of the battery's end cap assembly is a key parameter affecting the battery's energy density per unit volume; excessive thickness reduces the battery's energy density per unit volume. Current end cap assemblies include a lower plastic layer that insulates the top cap from the terminal. This layer is typically designed to be very thin to increase the battery's energy density per unit volume.

[0004] Currently, the lower plastic is made using an injection molding process. When demolding after injection molding is completed, the mold pulls on the lower plastic, which can easily cause damage to the lower plastic. In addition, the electrolyte in the energy storage device may splash onto the lower plastic and remain on the lower plastic, resulting in a decrease in the electrolyte content in the battery cell assembly, reducing the utilization rate of the electrolyte and possibly shortening the service life of the energy storage device. Summary of the Invention

[0005] The purpose of this application is to provide a lower plastic, an end cover assembly, an energy storage device and an electrical device to solve the problems of damage to the lower plastic during demolding, and the electrolyte remaining on the lower plastic, resulting in reduced electrolyte utilization and shortening the service life of the energy storage device.

[0006] To achieve the purpose of this application, this application provides the following technical solutions:

[0007] In the first aspect, the present application provides a lower plastic, an end cover assembly for an energy storage device, comprising: a body, comprising a first surface and a second surface opposite to each other, the first surface being arranged on the side facing the top cover; an explosion-proof sinking platform, arranged in the middle of the length direction of the body, and protruding relative to the second surface, the top surface of the explosion-proof sinking platform protruding from the second surface is the first top surface, the explosion-proof sinking platform is recessed relative to the first surface, so that the explosion-proof sinking platform encloses a gas collecting groove, and the bottom wall of the gas collecting groove is the first bottom wall; the first sinking platform is arranged at one end of the length direction of the body, and is relative to the second surface The first surface is raised, the top surface of the first sink protruding from the second surface is the second top surface, the first sink is recessed relative to the first surface, so that the first sink is enclosed to form a first sink, and the bottom wall of the first sink is the second bottom wall; the second sink is arranged at one end of the body away from the first sink in the length direction of the body, and is raised relative to the second surface, the top surface of the second sink protruding from the second surface is the third top surface, the second sink is recessed relative to the first surface, so that the second sink is enclosed to form a second sink, and the bottom wall of the second sink is the third bottom wall; the first pole boss, The first pole boss is provided on the body and is located between the explosion-proof sunken platform and the first sunken platform. The first pole boss is raised relative to the first surface. The top surface of the first pole boss protruding from the first surface is the fourth top surface. The first pole boss is recessed relative to the second surface so that the first pole boss encloses and forms a first pole groove. The bottom wall of the first pole groove is the fourth bottom wall. The second pole boss is provided on the body and is located between the explosion-proof sunken platform and the second sunken platform. The second pole boss is raised relative to the first surface. The second pole boss protrudes from the top of the first surface. The surface is the fifth top surface, the second pole boss is recessed relative to the second surface so that the second pole boss encloses a second pole groove, and the bottom wall of the second pole groove is the fifth bottom wall; wherein, the first surface, the second bottom wall, the third bottom wall, the fourth bottom wall and the fifth bottom wall all have a first surface roughness, the second surface, the first bottom wall, the first top surface, the second top surface, the third top surface, the fourth top surface and the fifth top surface all have a second surface roughness, the first surface roughness is A, the second surface roughness is B, and the following conditions are satisfied: A<B.

[0008] By setting the first surface roughness of the first surface and the second surface roughness of the second surface to satisfy A<B, after the lower plastic is installed on the energy storage device, the electrolyte splashed onto the relatively flat and smooth first surface can be flattened and flow back to the battery cell assembly along the edge of the first surface, and the electrolyte droplets splashed onto the relatively rough second surface can form a hanging hemispherical shape and fall back to the battery cell assembly with a slight vibration. In this way, the electrolyte splashed onto the lower plastic can return to the battery cell assembly to form an ion channel between the positive electrode sheet and the negative electrode sheet, thereby preventing the electrolyte from remaining on the lower plastic and not participating in the electrochemical reaction of the battery cell assembly, thereby improving the utilization rate of the electrolyte and further improving the service life of the energy storage device. The second surface roughness of the second surface is set to satisfy A<B. The second surface is rougher than the first surface. When the second mold is demolded, gas can enter between the lower plastic and the second mold through the microscopic gap between the relatively rough second surface and the second mold, thereby avoiding the generation of local negative pressure between the second surface and the second mold, which would cause a large adsorption force and difficulty in demolding. This makes the second mold easier to separate from the lower plastic than the first mold. That is, when the second mold is separated from the lower plastic, the first mold still tightly adsorbs the lower plastic, thereby preventing the second mold from pulling out the local structure of the lower plastic, causing local deformation and damage to the lower plastic, and thus improving the product yield.

[0009] In a second aspect, the present application provides an end cover assembly, comprising a top cover and the lower plastic described in any one of the first aspects, wherein the first surface of the lower plastic faces the top cover.

[0010] In a third aspect, the present application provides an energy storage device comprising a shell, a battery cell assembly, and the end cap assembly described in the second aspect, wherein the battery cell assembly is disposed in the shell, and the end cap assembly is connected to the shell.

[0011] In a fourth aspect, the present application provides an electrical device, comprising an electrical device and the energy storage device described in the third aspect, wherein the energy storage device supplies power to the electrical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the implementation methods or the description of the prior art. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0013] FIG1 is a diagram of an application scenario of an energy storage device according to an embodiment;

[0014] FIG2 is a perspective view of the lower plastic of an embodiment;

[0015] FIG3 is a perspective view of the lower plastic of an embodiment from another perspective;

[0016] FIG4 is a schematic diagram of lower plastic injection molding according to an embodiment;

[0017] FIG5 is an exploded view of the lower plastic injection molding of an embodiment;

[0018] FIG6 is a top view of the lower plastic of an embodiment;

[0019] FIG7 is a bottom view of the lower plastic of an embodiment;

[0020] FIG8 is a perspective view of the lower plastic of another embodiment;

[0021] FIG9 is a side view of the lower plastic of another embodiment;

[0022] FIG. 10 is a bottom view of the lower plastic of another embodiment.

[0023] Description of reference numerals:

[0024] 1000-energy storage device, 2000-photovoltaic panel, 3000-wind turbine, 4000-grid;

[0025] 10-lower plastic, 11-body, 111-first surface, 112-second surface; 12-explosion-proof sink, 121-first boss, 1211-first sub-top surface, 1212-first sub-bottom wall, 1213-first vent, 122-second boss, 1221-second sub-top surface, 1222-second sub-bottom wall, 1223-second vent, 123-gas collecting groove, 124-first outer surface, 125-first inner wall; 13-first sink, 131-second top surface, 132-second outer surface, 133-first sink, 134-second inner wall, 135-second bottom wall, 136-first leakage hole, 137-first reinforcement rib, 1371-third surface, 138-first groove; 14-second sink , 141-third top surface, 142-third outer surface, 143-second sink, 144-third inner wall, 145-third bottom wall, 146-second leakage hole, 147-second reinforcement rib, 1471-fourth surface, 148-second groove; 15-first pole boss, 151-fourth top surface, 152-fourth outer surface, 153-first pole groove, 154-fourth inner wall, 155-fourth bottom wall, 156-first pole hole, 16-second pole boss, 161-fifth top surface, 162-fifth outer surface, 163-second pole groove, 164-fifth inner wall, 165-fifth bottom wall, 166-second pole hole; 17-anti-rotation column, 171-sixth top surface, 18-micro texture, 19-connecting rib;

[0026] 201 - clamping surface, 21 - first mold, 211 - first shaping surface, 212 - first shaping groove, 213 - push hole, 22 - second mold, 221 - second shaping surface, 222 - second shaping groove, 223 - docking part, 224 - docking surface, 225 - pouring hole;

[0027] X-first direction, Y-second direction, Z-third direction. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0029] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may be an intermediate component. When a component is referred to as being "connected to" another component, it may be directly connected to the other component or there may be an intermediate component.

[0030] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art to which this application belongs. The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used in this application includes any and all combinations of one or more of the relevant listed items.

[0031] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features therein may be combined with each other.

[0032] Because the energy people need is highly temporal and spatially dependent, rationally utilizing energy and improving its efficiency requires a medium or device that can store one form of energy in the same form or convert it into another, allowing it to be released in a specific form based on future application needs. As we all know, to achieve the goal of carbon neutrality, the primary method for generating green electricity is to develop green energy sources such as photovoltaics and wind power to replace fossil fuels. Currently, green electricity generation generally relies on photovoltaics, wind power, and hydropower. However, wind and solar power are generally intermittent and volatile, leading to grid instability, insufficient power during peak hours, and excessive power during off-peak hours. Unstable voltage can also damage electricity. Therefore, insufficient electricity demand or insufficient grid capacity can lead to "wind and solar curtailment." Addressing these issues requires energy storage. That is, electrical energy is converted into other forms of energy through physical or chemical means and stored, and then the energy is converted into electrical energy and released when needed. Simply put, energy storage is like a large "power bank". When there is sufficient photovoltaic and wind energy, electrical energy is stored and the stored electricity is released when needed.

[0033] Taking electrochemical energy storage as an example, this solution provides an energy storage device with a group of chemical batteries inside. The energy storage device mainly uses the chemical elements in the chemical batteries as energy storage media. The charging and discharging process is accompanied by chemical reactions or changes in the energy storage medium. Simply put, the electricity generated by wind and solar energy is stored in the chemical batteries. When the use of external electricity reaches its peak, the stored electricity is released for use, or transferred to places where electricity is scarce for use.

[0034] Currently, energy storage (i.e., energy storage) has a wide range of application scenarios, including (wind and solar) power generation-side energy storage, grid-side energy storage, base station-side energy storage, and user-side energy storage. The corresponding energy storage device types include:

[0035] (1) Large energy storage containers used in grid-side energy storage scenarios can serve as high-quality active and reactive power regulation power sources in the grid, achieving load matching of electricity in time and space, enhancing the ability to absorb renewable energy, and are of great significance in grid system backup, alleviating peak load power supply pressure, and peak and frequency regulation.

[0036] (2) Small and medium-sized energy storage cabinets used in industrial and commercial energy storage scenarios (banks, shopping malls, etc.) on the user side mainly operate in the "peak shaving and valley filling" mode. Since there is a large price difference in electricity prices at peak and valley locations according to electricity demand, after users have energy storage equipment, in order to reduce costs, they usually charge the energy storage cabinets / boxes during the low electricity price period; during the peak electricity price period, they release the electricity in the energy storage equipment for use, thereby saving electricity costs.

[0037] Please refer to Figure 1. The energy storage device 1000 provided in the embodiment of the present application is applied to an energy storage system, which includes an energy storage device 1000, an electric energy conversion device (photovoltaic panel 2000), a wind energy conversion device (wind turbine 3000), a power grid 4000, etc. The energy storage device 1000 can be used as an energy storage cabinet and can be installed outdoors. Specifically, the photovoltaic panel 2000 can convert solar energy into electric energy during the period of low electricity prices. The energy storage device 1000 is used to store the electric energy and supply it to the power grid 4000 during peak electricity consumption, or to supply power when the power grid 4000 is out of power / power outage. The wind energy conversion device (wind turbine 3000) can convert wind energy into electric energy. The energy storage device 1000 is used to store the electric energy and supply it to the power grid 4000 during peak electricity consumption, or to supply power when the power grid 4000 is out of power / power outage. Among them, the transmission of electric energy can be carried out using high-voltage cables.

[0038] There may be multiple energy storage devices 1000, each connected in series or in parallel. These devices 1000 are supported and electrically connected using an isolation plate (not shown). In this embodiment, "multiple" refers to two or more. An energy storage box may also be provided externally to the energy storage device 1000 to house the energy storage device 1000.

[0039] It is understood that the energy storage device 1000 may include, but is not limited to, single cells, battery modules, battery packs, and battery systems. The energy storage device provided in the embodiments of this application may be applied in, but is not limited to, the products listed above, or in other application forms. The embodiments of this application do not impose strict limitations on the application form of the energy storage device 1000.

[0040] Referring to Figure 1 , an embodiment of the present application provides an electrical device, including an electrical device and an energy storage device 1000 in the embodiment of the present application. Energy storage device 1000 supplies power to the electrical device. The electrical device can be a power generation-side device, a grid-side device, a base station-side device, a user-side device, or the like. Specifically, the electrical device can be any type of electrical load, without limitation.

[0041] 1 and 2 , an embodiment of the present application further provides an energy storage device 1000, comprising a housing (not shown), a battery cell assembly (not shown), and an end cap assembly (not shown) in any embodiment of the present application, wherein the battery cell assembly is disposed in the housing, and the end cap assembly is connected to the housing.

[0042] The shell can be a square shell and can be made of aluminum or steel without limitation. The shell has a storage space in which the battery cell assembly is accommodated. One or both ends of the storage space are open, and an end cap assembly is provided at the position of the opening. The end cap assembly is fixedly connected to the shell and closes the opening. The battery cell assembly can specifically include one or more battery cells, and the battery cells are connected to the tabs. The end cap assembly can include a top cover (not shown), a lower plastic 10, a pole (not shown), an explosion-proof valve (not shown), etc. The lower plastic 10 is provided on the side of the top cover facing the battery cell assembly, and the pole is provided through the lower plastic 10 and the top cover, and the pole is insulated from the top cover. The pole is connected to the tab, and an external power supply is connected to the pole to charge the battery cell through the tab. The electrical energy of the battery cell can also be transmitted to an external electrical load through the tab and the pole. The explosion-proof valve is provided on the top cover. When the battery cell assembly generates a large amount of gas due to abnormal heat, the explosion-proof valve can explode to release the gas to prevent the energy storage device from exploding.

[0043] 2 , the present invention also provides an end cap assembly, comprising a top cap and the lower plastic 10 of any embodiment of the present invention, with the first surface 111 of the lower plastic 10 facing the top cap. The end cap assembly can be referred to above and will not be further limited here.

[0044] The lower plastic of the embodiment of the present application is described in detail below.

[0045] 2 and 3 , an embodiment of the present application provides a lower plastic 10, which is used for an end cap assembly of an energy storage device 1000. The lower plastic 10 is formed by injection molding, and all structures included in the lower plastic 10 described below are integral structures formed by injection molding.

[0046] The lower plastic member 10 specifically includes a body 11, which includes a first surface 111 and a second surface 112 facing each other. The first surface 111 is located on the side facing the top cover, and the second surface 112 is located on the side facing the battery cell assembly. The body 11 is generally a thin sheet-like structure. The first and second surfaces 111, 112 are generally flat, but may also be slightly curved. The first and second surfaces 111, 112 are generally rectangular.

[0047] A coordinate system is established for ease of description. A first direction X is the length direction of the body 11, which also corresponds to the length direction of the first surface 111, the second surface 112, and the lower plastic 10. A second direction Y is the width direction of the body 11, which also corresponds to the width direction of the first surface 111, the second surface 112, and the lower plastic 10. A third direction Z is the thickness direction of the body 11, which is the relative direction between the first surface 111 and the second surface 112, and the thickness direction of the lower plastic 10.

[0048] The first surface 111 has a first surface roughness, and the second surface 112 has a second surface roughness. The first surface roughness is A, and the second surface roughness is B, satisfying: A<B. That is, the first surface 111 is smoother than the second surface 112, and the second surface 112 is rougher than the first surface 111.

[0049] The lower plastic 10 is installed to form an end cap assembly. After the end cap assembly is installed to form the energy storage device 1000, the first surface 111 is roughly the side facing away from the center of the earth, and the second surface 112 is roughly the side facing the center of the earth. A top cover is provided above the lower plastic 10 (i.e., the side facing away from the center of the earth), and a battery cell assembly is provided below the lower plastic 10 (i.e., the side facing the center of the earth). The battery cell assembly is soaked in electrolyte. During operation or transportation of the energy storage device 1000, the electrolyte soaked in the battery cell assembly may splash onto the first surface 111 and the second surface 112 of the lower plastic 10 due to vibration, shaking, etc. If the lower plastic 10 is not specially designed, the electrolyte may remain on the lower plastic 10 and will not return to the battery cell assembly, thereby reducing the electrolyte content in the battery cell assembly, reducing the utilization rate of the electrolyte, and possibly shortening the service life of the energy storage device 1000.

[0050] The embodiment of the present application has a special design for the lower plastic 10. Specifically, the first surface roughness and the second surface roughness of the first surface 111 of the main body 11 are set to satisfy A<B, so that the first surface 111 is flatter and smoother than the second surface 112. The droplets of electrolyte on the first surface 111 are flattened under the action of gravity and surface tension, and flow back to the battery cell assembly along the edge of the main body 11, providing ion channels for the positive and negative electrodes in the battery cell assembly. The second surface 112 is made rougher than the first surface 111. Under the influence of gravity, surface tension and the relatively rough second surface 112, the droplets of electrolyte on the second surface 112 will adhere to and wrap around the microscopic protrusions of the second surface 112, and macroscopically converge into granular shapes and form a suspended hemisphere. With a slight vibration, they can fall back to the battery cell assembly, providing ion channels for the positive and negative electrodes.

[0051] Therefore, the lower plastic 10 provided in the embodiment of the present application satisfies A<B by setting the first surface roughness of the first surface 111 and the second surface roughness of the second surface 112. After the lower plastic 10 is installed on the energy storage device 1000, the electrolyte splashed onto the relatively flat and smooth first surface 111 can be flattened and flow back to the battery cell assembly along the edge of the first surface 111. The droplets of electrolyte splashed onto the relatively rough second surface 112 can form a hanging hemispherical shape and fall back to the battery cell assembly with a slight vibration. In this way, the electrolyte splashed onto the lower plastic 10 can return to the battery cell assembly to form an ion channel between the positive electrode sheet and the negative electrode sheet, thereby preventing the electrolyte from remaining on the lower plastic 10 and not participating in the electrochemical reaction of the battery cell assembly, thereby improving the utilization rate of the electrolyte and further improving the service life of the energy storage device 1000.

[0052] Optionally, the first surface roughness and the second surface roughness further satisfy the following conditions: Ra0.02≤A≤Ra1.6, Ra0.8≤B≤Ra12.5. The first surface roughness of the first surface 111 of the body 11 is set to satisfy Ra0.02≤A≤Ra1.6, making the first surface 111 relatively flat and smooth. Droplets of electrolyte on the first surface 111 are flattened by gravity and surface tension, and flow back along the edge of the body 11 to the battery cell assembly, providing ion channels for the positive and negative electrodes in the battery cell assembly. The second surface roughness of the second surface 112 is set to satisfy Ra0.8≤B≤Ra12.5, making the second surface 112 relatively rough. Under the influence of gravity, surface tension and the relatively rough second surface 112, the droplets of electrolyte on the second surface 112 will adhere to and wrap around the microscopic protrusions of the second surface 112, and macroscopically converge in a granular shape and form a hanging hemisphere. With a slight vibration, they can fall back to the battery cell assembly, providing ion channels for the positive and negative electrodes.

[0053] The first surface roughness can be any one of Ra0.02, Ra0.05, Ra0.1, Ra0.15, Ra0.2, Ra0.25, Ra0.3, Ra0.35, Ra0.4, Ra0.45, Ra0.5, Ra0.55, Ra0.6, Ra0.65, Ra0.7, Ra0.75, Ra0.8, Ra0.85, Ra0.9, Ra0.95, Ra1, Ra1.05, Ra1.15, Ra1.2, Ra1.25, Ra1.3, Ra1.35, Ra1.4, Ra1.45, Ra1.5, Ra1.55, Ra1.6, etc., and can also be other values, which are not specifically limited.

[0054] The second surface roughness can be any one of Ra0.8, Ra1, Ra1.5, Ra2, Ra2.5, Ra3, Ra3.5, Ra4, Ra4.5, Ra5, Ra5.5, Ra6, Ra6.5, Ra7, Ra7.5, Ra8, Ra8.5, Ra9, Ra9.5, Ra10, Ra10.5, Ra11, Ra11.5, Ra12, Ra12.5, etc., and can also be other values, without specific limitation.

[0055] When the first surface roughness satisfies Ra0.02≤A≤Ra1.6, the manufacturing process of the first surface 111 is relatively easy, easy to implement, and low in cost. Furthermore, the first surface 111 is relatively flat and smooth, allowing the electrolyte on the first surface 111 to flow smoothly back from the edge to the battery cell assembly. If A < Ra0.02, the process is more difficult and more difficult to process, resulting in higher costs. If A > Ra1.6, the first surface 111 is not sufficiently flat and smooth, making it difficult for the electrolyte to flow to the edge of the first surface 111 and potentially remaining on the first surface 111, resulting in reduced electrolyte utilization.

[0056] The second surface roughness satisfies Ra0.8≤B≤Ra12.5, and the second surface 112 has a relatively rough surface, so that the droplets of the electrolyte can form a hanging shape and fall to the battery cell assembly under slight vibration. If B<Ra0.8, the second surface 112 is relatively smooth, and the electrolyte easily forms a flat sheet, and it is difficult to form droplets that wrap around the microscopic protrusions and hang. If B>Ra12.5, the second surface 112 is too rough, the size of the microscopic protrusions is large, and the area of ​​the outer surface of the microscopic protrusions is large. The electrolyte will adhere to the outer surface of the microscopic protrusions but will not hang, and will require a large vibration to fall. Large vibrations may damage the energy storage device 1000, which is not conducive to improving the service life of the energy storage device 1000.

[0057] Optionally, the first surface roughness may also satisfy: Ra0.05≤A≤Ra1.2. This further reduces the process difficulty and allows the electrolyte on the first surface 111 to flow back to the battery cell assembly from the edge more easily.

[0058] Optionally, the second surface roughness may also satisfy: Ra2≤B≤Ra10. In this way, the electrolyte droplets can more easily wrap around the microscopic protrusions and form a hanging shape, so that they can more easily fall onto the battery cell assembly with slight vibration.

[0059] In one embodiment, referring to Figures 2 and 3 , the lower plastic 10 further includes an explosion-proof sunken platform 12, a first sunken platform 13, and a second sunken platform 14. The explosion-proof sunken platform 12 is disposed in the middle of the lengthwise direction of the body 11, while the first sunken platform 13 and the second sunken platform 14 are disposed at opposite ends of the lengthwise direction of the body 11. The explosion-proof sunken platform 12, the first sunken platform 13, and the second sunken platform 14 are all recessed relative to the first surface 111 and raised relative to the second surface 112.

[0060] Among them, the explosion-proof sinking platform 12, the first sinking platform 13 and the second sinking platform 14 are all integral structures of injection molding with the main body 11. The other structures on the lower plastic 10 mentioned below are also integral structures of injection molding and will not be repeated in the following text.

[0061] The explosion-proof sink 12 extends along the width direction of the main body 11, that is, the length direction of the explosion-proof sink 12 is the width direction of the main body 11. The explosion-proof sink 12 is recessed relative to the first surface 111 so that the explosion-proof sink 12 encloses a gas collecting groove 123, and the opening of the gas collecting groove 123 is located at the first surface 111. A vent is provided on the bottom wall of the gas collecting groove 123, and the vent passes through the explosion-proof sink 12 so that the space on the second surface 112 side is connected to the gas collecting groove 123 through the vent. After the lower plastic 10 is installed on the energy storage device 1000, the gas generated by the battery cell assembly can flow to the gas collecting groove 123 through the vent. The gas collecting groove 123 corresponds to the explosion-proof valve provided on the top cover. When the air pressure is greater than the preset value, the explosion-proof valve will explode to release air to prevent the internal air pressure of the energy storage device 1000 from being too high and causing an explosion. There is no limitation on the specific structure of the explosion-proof sink 12, the gas collecting groove 123, and the vent.

[0062] Both the first and second recessed platforms 13 and 14 extend along the width of the body 11, meaning their lengths are aligned with the width of the body 11. The first and second recessed platforms 13 and 14 are recessed relative to the first surface 111, so that the first recessed platform 13 encloses a first trough 133, and the second recessed platform 14 encloses a second trough 143. The openings of the first and second troughs 133 and 143 are both located on the first surface 111. A first leakage hole 136 is defined in the bottom wall of the first trough 133, which extends through the first recessed platform 13. A second leakage hole 146 is defined in the bottom wall of the second recessed platform 143, which extends through the second recessed platform 14. After the lower plastic 10 is installed in the energy storage device 1000, the electrolyte on the first surface 111 can flow into the first and second troughs 133 and 143, and then leak into the battery cell assembly through the first and second leakage holes 136 and 146. There is no limitation on the specific structures of the first sinking platform 13 , the second sinking platform 14 , the first sinking groove 133 , the second sinking groove 143 , the first leakage hole 136 , and the second leakage hole 146 .

[0063] The explosion-proof sunken platform 12, the first sunken platform 13, and the second sunken platform 14 can protrude from the second surface 112 to the same height. After the lower plastic 10 is installed in the energy storage device 1000, the explosion-proof sunken platform 12, the first protrusion 121, and the second protrusion 122 can contact the battery cell assembly, thereby creating a gap between the body 11 and the battery cell assembly, forming a receiving space. This receiving space can be used to accommodate other components of the energy storage device 1000, such as tabs and connecting pieces. Gas from the battery cell assembly can also flow through this receiving space and enter the gas collecting groove 123.

[0064] The lower plastic 10 also includes a first pole boss 15 and a second pole boss 16. The first pole boss 15 and the second pole boss 16 are spaced apart from each other on the body 11 and are both raised relative to the first surface 111 and recessed relative to the second surface 112. The first pole boss 15 encloses a first pole slot 153, and the second pole boss 16 encloses a second pole slot 163. The openings of the first pole slot 153 and the second pole slot 163 are located at the second surface 112. The first pole boss 15 is disposed between the first sink 13 and the explosion-proof sink 12, and the second pole boss 16 is disposed between the second sink 14 and the explosion-proof sink 12. The first pole boss 15 defines a first pole hole 156, and the second pole boss 16 defines a second pole hole 166. When the lower plastic 10 is installed on the end cap assembly, the first pole of the end cap assembly is inserted into the first pole hole 156, and the second pole of the end cap assembly is inserted into the second pole hole 166. The first pole includes a first disk and a first column, and the second pole includes a second disk and a second column. The first disk is received in the first pole slot 153, the first column is inserted into the first pole hole 156, the second disk is received in the second pole slot 163, and the second column is inserted into the second pole hole 166. The specific structure of the first pole boss 15, the second pole boss 16, the first pole hole 156, the second pole hole 166, the first pole slot 153, the second pole slot 163, the first pole, and the second pole is not limited.

[0065] The lower plastic 10 also includes an anti-rotation column 17, which is connected to the body 11 and protrudes from the first surface 111. The anti-rotation column 17 is used to extend into the limiting groove on the top cover to position the installation between the lower plastic 10 and the top cover, and limit the displacement of the top cover and the lower plastic 10 in the length and width directions of the body 11. There can be multiple anti-rotation columns 17, and multiple anti-rotation columns 17 are arranged at intervals. For example, as shown in Figure 2, an anti-rotation column 17 is provided on each side of the first pole boss 15 along the width direction of the body 11, and an anti-rotation column 17 is provided on each side of the second pole boss 16 along the width direction of the body 11, for a total of 4 anti-rotation columns 17. Providing multiple anti-rotation columns 17 can improve the positioning and limiting effects.

[0066] Referring to Figures 4 and 5 , the lower plastic 10 is formed by injection molding after the first mold 21 (fixed mold) and the second mold 22 (movable mold) are molded together. The surface where the first mold 21 and the second mold 22 meet is the mold surface 201, as shown by the dotted line in Figure 4 . In this embodiment of the present application, the first mold 21 and the second mold 22 are connected in the third direction Z (the thickness direction of the lower plastic 10), and the mold surface 201 coincides with the first surface 111. After the injection molding is completed, the demolding direction is also the third direction Z.

[0067] The first mold 21 has a first shaping surface 211, which is planar and extends to the edge of the first mold 21. The first shaping surface 211 may be provided with a recessed first shaping groove 212, which corresponds to the structure protruding from the first surface 111 of the lower plastic 10. The number and shape of the first shaping grooves 212 can be adapted to the number and shape of the structures protruding from the first surface 111 of the lower plastic 10, and are not specifically limited thereto.

[0068] The second mold 22 has a second shaping surface 221. This second shaping surface 221 is planar but located in the center of the first mold 21, a certain distance from the edge of the first mold 21. The second shaping surface 221 may be provided with a recessed second shaping groove 222. The second shaping groove 222 corresponds to the structure protruding from the second surface 112 of the lower plastic member 10. The number and shape of the second shaping grooves 222 can be adjusted to suit the number and shape of the structures protruding from the second surface 112 of the lower plastic member 10, and are not particularly limited thereto.

[0069] The second mold 22 is also provided with a docking portion 223 protruding from the second shaping surface 221 on all four edges. The second shaping surface 221 can extend to connect with the side of the docking portion 223. The top surface of the docking portion 223 protruding from the first surface 111 is a docking surface 224. The docking surface 224 is used to be in close contact with the first shaping surface 211 of the first mold 21.

[0070] During injection molding, the first mold 21 and the second mold 22 are docked so that the docking surface 224 is in close contact with the first shaping surface 211. At this time, a gap is formed between the first shaping surface 211 and the second shaping surface 221 to form a cavity. The first shaping groove 212 and the second shaping groove 222 are connected to the cavity and together form a mold cavity. Molten plastic liquid is poured into the mold cavity. After the plastic liquid fills the mold cavity, it is cooled. After the plastic liquid cools and solidifies, the lower plastic 10 can be formed. Among them, the first shaping surface 211 is used to form the first surface 111 of the lower plastic 10, the second shaping surface 221 is used to form the second surface 112 of the lower plastic 10, the first shaping groove 212 is used to form a structure of the lower plastic 10 protruding from the first surface 111, and the second shaping groove 222 is used to form a structure of the lower plastic 10 protruding from the second surface 112.

[0071] During demolding, the second mold 22 is first moved away from the first mold 21 to separate the second mold 22 from the lower plastic 10 , and then a push rod (not shown) is used to push the lower plastic 10 away from the first mold 21 to separate the lower plastic 10 from the first mold 21 .

[0072] In the embodiments of the present application, during injection molding, there is no need to wait for the plastic to cool to room temperature before demolding. Instead, demolding can be performed only after the plastic liquid solidifies and forms at a relatively high temperature, thereby improving production efficiency. Plastic that has not fully cooled to room temperature may leave traces when subjected to external forces, forming specific shapes, such as the specific shapes formed on first surface 111 in Figure 2, although these are not specifically limited. Due to the optimization of the injection molding process, these traces do not affect the functional performance of the lower plastic 10, but can significantly improve production efficiency.

[0073] In the embodiment of the present application, the first surface roughness of the first surface 111 is formed by the first shaping surface 211 of the first mold 21, and the second surface roughness of the second surface 112 is formed by the second shaping surface 221 of the second mold 22. The first shaping surface 211 and the second shaping surface 221 can be processed and manufactured by specific mechanical processing processes, such as milling, grinding, polishing and other processes, to obtain the required surface roughness characteristics, without specific limitation.

[0074] Referring to Figures 4 and 5 , the first mold 21 is provided with a push-out hole 213 extending through the thickness direction (i.e., the third direction Z) of the lower plastic 10. During the injection molding process, the push-out hole 213 can be blocked by a plunger or other structure to prevent the plastic liquid from entering the push-out hole 213. Upon demolding after injection molding, the plunger is removed and replaced with a push rod that extends into the push-out hole 213 to push the lower plastic 10 away from the first mold 21. The pressure from the push rod acts on the lower plastic 10, leaving traces of the push rod's action on the lower plastic 10. As shown in Figure 2 , the circular push points formed on the first surface 111 are traces of this process, resulting from the use of a relatively high-temperature demolding process.

[0075] Referring to Figures 4 and 5 , the second mold 22 is provided with a pouring hole 225 extending along a third direction Z. This pouring hole 225 communicates with the mold cavity and allows the flow of plastic liquid, thereby injecting the plastic liquid into the mold cavity. After the plastic liquid solidifies and forms, it is demolded. After demolding, a pouring mark remains on the lower plastic 10 at the location corresponding to the pouring hole 225, forming a gate. The gate can be a protrusion, a groove, or other structure, without limitation. The shape and size of the gate are also not limited.

[0076] In the embodiment of the present application, a gate is formed on the side of the second surface 112 facing away from the first surface 111. The gate can be located on at least one of the second surface 112, the explosion-proof sink 12, the first sink 13, and the second sink 14. This allows the first mold 21 and the second mold 22 to be used for pouring plastic and ejecting the mold with a push rod, respectively, with independent functions. This avoids the possibility of simultaneous pouring plastic and ejecting the mold with a push rod on the same mold, which could easily lead to misoperation and defects.

[0077] During the process of separating the second mold 22 from the lower plastic 10 , the second mold 22 exerts a certain pulling effect on the lower plastic 10 , which may cause the lower plastic 10 to separate from the first mold 21 , thereby causing local deformation and damage to the lower plastic 10 , resulting in low product yield.

[0078] In the embodiment of the present application, the second surface roughness of the second surface 112 is set to satisfy A<B. The second surface 112 is rougher than the first surface 111. When the second mold 22 is demolded, gas can enter between the lower plastic 10 and the second mold 22 through the microscopic gap between the relatively rough second surface 112 and the second mold 22, thereby avoiding the generation of local negative pressure between the second surface 112 and the second mold 22, which would cause a large adsorption force and difficulty in demolding. Therefore, the second mold 22 is easier to separate from the lower plastic 10 than the first mold 21. That is, when the second mold 22 is separated from the lower plastic 10, the first mold 21 still tightly adsorbs the lower plastic 10, thereby preventing the second mold 22 from pulling out the local structure of the lower plastic 10, causing local deformation and damage to the lower plastic 10, thereby improving the product yield.

[0079] The demolding of the first mold 21 of the present application is performed by using a push rod to act on the lower plastic 10. The push rod can be evenly arranged on the lower plastic 10 to achieve uniform force and avoid bending caused by local force imbalance. Therefore, the surface roughness value of the first surface 111 is relatively small, relatively flat and smooth, and will not cause bending and deformation of the lower plastic 10 during demolding.

[0080] In one embodiment, referring to Figures 3 and 7, the top surface of the explosion-proof sink 12 protruding from the second surface 112 is a first top surface, the top surface of the first sink 13 protruding from the second surface 112 is a second top surface 131, and the top surface of the second sink 14 protruding from the second surface 112 is a third top surface 141. The first top surface, the second top surface 131, and the third top surface 141 all have a second surface roughness.

[0081] Similar to the aforementioned second surface 112 having a second surface roughness, the first top surface, the second top surface 131, and the third top surface 141 of this embodiment have a second surface roughness, which allows droplets of electrolyte to be suspended and fall back to the battery cell assembly with a slight vibration, providing an ion channel for the positive and negative electrodes. In addition, the lower plastic 10 can be easily separated from the mold during demolding, avoiding local deformation and damage of the lower plastic 10, thereby improving product yield.

[0082] In one embodiment, referring to Figures 2, 3 and 7, the explosion-proof sink 12 includes a first boss 121 and two second bosses 122. The first boss 121 is arranged in the middle of the width direction of the main body 11, and the first boss 121 is connected to a second boss 122 at both ends of the width direction of the main body 11. The height of the first boss 121 relative to the second surface 112 is less than the height of the second boss 122 relative to the second surface 112. The first top surface includes a first sub-top surface 1211 and a second sub-top surface 1221. The top surface of the first boss 121 protruding from the second surface 112 is the first sub-top surface 1211, and the top surface of the second boss 122 protruding from the second surface 112 is the second sub-top surface 1221. The first sub-top surface 1211 and the second sub-top surface 1221 both have a second surface roughness.

[0083] The vents include a first vent 1213 and a second vent 1223. The first boss 121 defines a through-hole for the first vent 1213, and the second boss 122 defines a through-hole for the second vent 1223. Both the first vent 1213 and the second vent 1223 communicate with the space on one side of the second surface 112 and the gas collecting groove 123. The shape and structure of the first vent 1213 and the second vent 1223 are not limited. Optionally, the first vent 1213 can be a strip-shaped hole, or there can be multiple first vents 1213. The multiple strip-shaped holes generally form a ring-shaped structure, with a fence formed on the first boss 121. The fence prevents foreign matter from moving from the battery cell assembly to the top cover. Optionally, the second vent 1223 can be a circular hole, or there can be multiple second vents 1223. The multiple second vents 1223 can be evenly spaced.

[0084] The first boss 121 is set to be lower than the height of the second boss 122 relative to the second surface 112, so that when the second boss 122 contacts the battery cell assembly, there is still a certain gap between the first boss 121 and the battery cell assembly, so that gas can flow between the left and right sides of the explosion-proof sinking platform 12 (i.e., the two sides in the length direction of the main body 11) through the gap between the first boss 121 and the battery cell assembly, avoiding local accumulation of gas and causing abnormalities. In addition, some devices can also be arranged in the gap to maximize the use of space, which is conducive to the miniaturization of the energy storage device 1000.

[0085] The first sub-top surface 1211 and the second sub-top surface 1221 are provided with the surface roughness of the second surface 112, so that the droplets of electrolyte can be suspended and fall back to the battery cell assembly with a slight vibration, providing an ion channel for the positive and negative electrodes. In addition, the lower plastic 10 can be easily separated from the mold during demolding, avoiding local deformation and damage of the lower plastic 10, thereby improving the product yield.

[0086] In one embodiment, referring to Figures 2 and 6 , the bottom wall of the gas collecting groove 123 is a first bottom wall, which includes a first sub-bottom wall 1212 and a second sub-bottom wall 1222. The depth of the first boss 121 recessed relative to the first surface 111 is less than the depth of the second boss 122 recessed relative to the first surface 111. The bottom wall of the gas collecting groove 123 corresponding to the first boss 121 is the first sub-bottom wall 1212, and the bottom wall of the gas collecting groove 123 corresponding to the second boss 122 is the second sub-bottom wall 1222. Both the first sub-bottom wall 1212 and the second sub-bottom wall 1222 have a second surface roughness.

[0087] The distance between the first sub-bottom wall 1212 and the first surface 111 is smaller than the distance between the second sub-bottom wall 1222 and the first surface 111. Combined with the aforementioned fact that the height of the first sub-top surface 1211 relative to the second surface 112 is lower than that of the second sub-top surface 1221, the wall thickness at the bottom wall of the first boss 121 and the second boss 122 can be roughly uniform, avoiding the situation where the wall thickness is locally too thick or too thin, thereby ensuring structural strength.

[0088] 4 and 5 , during injection molding, the first sub-bottom wall 1212 and the second sub-bottom wall 1222 are formed by the first mold 21. Because the explosion-proof boss has a relatively complex structure, specifically comprising a first boss 121, a second boss 122, a first vent 1213, a second vent 1223, and the like, to facilitate demolding, the first sub-bottom wall 1212 and the second sub-bottom wall 1222 are also provided with a second surface roughness. A rougher surface is more conducive to demolding. The specific principle can be referred to the aforementioned explanation of the second surface roughness of the second surface 112 being conducive to demolding, which will not be repeated here. This makes demolding easier, thereby preventing the first and second bosses 121, 122 from being difficult to demold from the first mold 21, which could cause deformation and damage to the first and second bosses 121, 122.

[0089] Optionally, referring to FIG3 , the explosion-proof sink 12 has a first outer side surface 124, the first sink 13 has a second outer side surface 132, and the second sink 14 has a third outer side surface 142. The first outer side surface 124 connects the second surface 112 and the first top surface, the second outer side surface 132 connects the second surface 112 and the second top surface 131, and the third outer side surface 142 connects the second surface 112 and the third top surface 141. The first outer side surface 124, the second outer side surface 132, and the third outer side surface 142 have a first surface roughness.

[0090] Among them, the first outer side surface 124 is the four side surfaces connecting the second surface 112 and the first top surface, the second outer side surface 132 is the four side surfaces connecting the second surface 112 and the second top surface 131, and the third outer side surface 142 is the four side surfaces connecting the second surface 112 and the third top surface 141. All three outer side surfaces extend along the third direction Z.

[0091] 4 and 5 , during injection molding, the plurality of second shaping grooves 222 of the second mold 22 are used to form the explosion-proof sink 12, the first sink 13, and the second sink 14. During demolding, friction occurs between the sidewalls of the second shaping grooves 222 (i.e., the inner wall surfaces extending along the third direction Z) and the outer side surfaces of the explosion-proof sink 12, the first sink 13, and the second sink 14 (i.e., the outer side surfaces extending along the third direction Z).

[0092] The first outer side surface 124 , the second outer side surface 132 and the third outer side surface 142 are provided with a first surface roughness, which is relatively flat and smooth, and can reduce the friction between the second mold 22 , thereby facilitating demolding and preventing the lower plastic 10 from being pulled and deformed by the second mold 22 and causing a decrease in product yield.

[0093] Optionally, referring to Figures 2 and 6 , the sidewall of gas collecting groove 123 is a first inner sidewall 125, the sidewall of first trough 133 is a second inner sidewall 134, and the sidewall of second trough 143 is a third inner sidewall 144. First inner sidewall 125, second inner sidewall 134, and third inner sidewall 144 are all connected to first surface 111. Furthermore, first inner sidewall 125, second inner sidewall 134, and third inner sidewall 144 all have a first surface roughness.

[0094] The first inner sidewall 125 is a peripheral sidewall of the gas collecting groove 123 and connects the first surface 111 and the first bottom wall. The first inner sidewall 125, the second inner sidewall 134 and the third inner sidewall 144 all extend along the third direction Z.

[0095] 4 and 5 , during injection molding, the multiple raised structures on the first shaping surface 211 of the first mold 21 are used to form the gas collecting groove 123, the first sink groove 133, and the second sink groove 143. During demolding, relative friction is generated between the outer surfaces of the raised structures of the first mold 21 (i.e., the outer surfaces extending along the third direction Z) and the first inner sidewall 125, the second inner sidewall 134, and the third inner sidewall 144.

[0096] The first inner sidewall 125 , the second inner sidewall 134 and the third inner sidewall 144 are all provided with the first surface roughness, which is relatively flat and smooth, thereby reducing the friction between the first mold 21 and facilitating demolding, thereby preventing the lower plastic 10 from being pulled and deformed by the first mold 21 and causing a decrease in product yield.

[0097] 2 and 6 , the bottom wall of the first sink 133 is the second bottom wall 135, and the bottom wall of the second sink 143 is the third bottom wall 145. Both the second bottom wall 135 and the third bottom wall 145 have a first surface roughness.

[0098] According to the above description, the electrolyte on the first surface 111 will flow into the first trough 133 and the second trough 143 after being flattened. The second bottom wall 135 and the third bottom wall 145 are set to have the first surface roughness, which is relatively flat and smooth. The electrolyte flowing to the second bottom wall 135 and the third bottom wall 145 is also easy to flatten and leak into the battery cell assembly from the first leakage hole 136 and the second leakage hole 146, just like the electrolyte on the first surface 111.

[0099] Since the first sinking platform 13 and the second sinking platform 14 are simpler in structure than the explosion-proof sinking platform 12, demoulding can be achieved by pushing the second bottom wall 135 and the third bottom wall 145 with a push rod, and there is no need to set the second bottom wall 135 and the third bottom wall 145 to the second surface roughness like the explosion-proof sinking platform 12.

[0100] Optionally, referring to Figures 2 and 6 , the lower plastic member 10 further includes a plurality of first reinforcing ribs 137 and a plurality of second reinforcing ribs 147. These first and second reinforcing ribs 137, 147 extend along the length of the body 11 and are spaced apart across the width of the body 11. Each first reinforcing rib 137 connects two opposing side walls and the bottom wall of the first trough 133 along the length of the body 11. Each second reinforcing rib 147 connects two opposing side walls and the bottom wall of the second trough 143 along the length of the body 11.

[0101] Multiple first reinforcing ribs 137 divide the first trough 133 into multiple sub-troughs. The aforementioned second inner sidewalls 134 can be the sidewalls of each of the multiple sub-troughs. The bottom wall of each sub-trough (also referred to as the second bottom wall 135) is provided with a first leakage hole 136. Multiple second reinforcing ribs 147 divide the second trough 143 into multiple sub-troughs. The aforementioned third inner sidewalls 144 can be the sidewalls of each of the multiple sub-troughs. The bottom wall of each sub-trough (also referred to as the third bottom wall 145) is provided with a second leakage hole 146.

[0102] The first reinforcing rib 137 and the second reinforcing rib 147 are provided to strengthen the structural strength of the first sinker 13 and the second sinker 14 in the first direction X. When the lower plastic 10 is installed on the energy storage device 1000, the battery cell assembly is first wrapped with a protective film, and then the protective film is welded to the side of the first sinker 13 away from the main body 11 (i.e., the second outer side 132), and to the side of the second sinker 14 away from the main body 11 (i.e., the third outer side 142). During hot melting, a hot melt pressing plate (such as a heated metal plate) is used to press the protective film against the side of the first sinker 13 away from the main body 11, and against the side of the second sinker 14 away from the main body 11, so that the protective film and the plastic are melted and fixed together. The first rib and the second rib are provided, and when the protective film is hot melted, the protective film and the hot melt pressing plate will not squeeze or pull the first sinker 13 and the second sinker 14 to deform, thereby causing hot melting failure and connection failure.

[0103] The first reinforcing rib 137 has a third surface 1371, and the second reinforcing rib 147 has a fourth surface 1471. The third surface 1371 and the fourth surface 1471 are both flush with the first surface 111. The third surface 1371 and the fourth surface 1471 have a second surface roughness.

[0104] Since the size of the reinforcing ribs is small, it is difficult to set a push rod on the third surface 1371 and the fourth surface 1471 to push and demould, so the third surface 1371 and the fourth surface 1471 are set to have a second surface roughness to facilitate demoulding. Having a second surface roughness can be beneficial to demoulding. Please refer to the previous description and will not be repeated here.

[0105] In one embodiment, referring to Figures 8 to 10, the dimensions (i.e., thickness) of the first reinforcing rib 137 and the second reinforcing rib 147 in the width direction of the main body 11 (i.e., the second direction Y) are both 0.85mm-3.65mm. The second top surface 131 has a first groove 138 at a position corresponding to the first reinforcing rib 137, and the third top surface 141 has a second groove 148 at a position corresponding to the second reinforcing rib 147. The first groove 138 is recessed from the second top surface 131 and passes through the two opposite outer side surfaces (i.e., the second outer side surface 132) of the first sink 13 along the length direction of the main body 11 (i.e., the first direction X), and the second groove 148 is recessed from the third top surface 141 and passes through the two opposite outer side surfaces (i.e., the third outer side surface 142) of the second sink 14 along the length direction of the main body 11.

[0106] Among them, the two side surfaces of the first reinforcing rib 137 and the second reinforcing rib 147 that are opposite to each other in the second direction Y may both be planes, one may be plane and the other may be curved, or both may be curved. The shapes of the first reinforcing rib 137 and the second reinforcing rib 147 may be the same or different, without limitation. The thickness of the first reinforcing rib 137 and the second reinforcing rib 147 refers to the average thickness or the minimum thickness. The thickness of the first reinforcing rib 137 and the second reinforcing rib 147 may specifically be 0.85mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 3.65mm, etc., without limitation. The thickness of the first reinforcing rib 137 and the thickness of the second reinforcing rib 147 may be equal or unequal, without limitation.

[0107] The thickness of the first reinforcing rib 137 and the second reinforcing rib 147 are both 0.85 mm to 3.65 mm. During injection molding, as the plastic liquid solidifies, the plastic will shrink toward the positions of the first reinforcing rib 137 on the second top surface 131 and the second reinforcing rib 147 on the third top surface 141, thereby forming a first groove 138 and a second groove 148, respectively.

[0108] After the lower plastic 10 is installed to form the energy storage device 1000, the second top surface 131 and the third top surface 141 are in contact with the battery cell assembly, while the first groove 138 and the second groove 148 can leave a gap between the battery cell assembly and the first groove 138 and the second groove 148. When electrolyte is injected into the energy storage device 1000, the electrolyte enters the surface of the battery cell assembly facing the lower plastic 10 and flows through the first groove 138 and the second groove 148 to the side and bottom walls of the battery cell assembly, soaking the battery cell assembly from all directions, improving the soaking efficiency and ensuring the uniformity of the soaking.

[0109] At the same time, the first groove 138 and the second groove 148 can be used for ventilation. When the battery cell assembly generates gas, the gas can enter the space between the second surface 112 and the battery cell assembly through the first groove 138 and the second groove 148, and then enter the gas collecting groove 123 through the vent hole. When the gas pressure exceeds a preset value, the explosion-proof valve explodes to release the pressure, thereby improving the safety performance of the energy storage device 1000.

[0110] 2 and 6 , the top surface of the first pole boss 15 protruding from the first surface 111 is a fourth top surface 151, and the top surface of the second pole boss 16 protruding from the first surface 111 is a fifth top surface 161. Both the fourth top surface 151 and the fifth top surface 161 have the second surface roughness.

[0111] 4 and 5 , when the first boss 121 and the second boss 122 are demolded from the first mold 21, the fourth top surface 151 and the fifth top surface 161 do not need to be provided with a push rod for pushing. It is only necessary to set the fourth surface 1471 and the fifth surface to have the second surface roughness. The rougher surface can facilitate demolding. The specific principle can be referred to the previous text and will not be repeated.

[0112] Optionally, referring to FIG2 , the first pole boss 15 has a fourth outer side surface 152, and the second pole boss 16 has a fifth outer side surface 162. The fourth outer side surface 152 connects the first surface 111 and the fourth top surface 151, and the fifth outer side surface 162 connects the first surface 111 and the fifth top surface 161. Both the fourth outer side surface 152 and the fifth outer side surface 162 have a first surface roughness.

[0113] The fourth outer side surface 152 is a peripheral side surface of the first pole boss 15 , and the fifth outer side surface 162 is a peripheral side surface of the second pole boss 16 . The fourth outer side surface 152 and the fifth outer side surface 162 extend substantially along the third direction Z.

[0114] 4 and 5 , during injection molding, the sidewalls of the plurality of first shaping grooves 212 on the first shaping surface 211 of the first mold 21 are used to form the fourth outer side surface 152 and the fifth outer side surface 162. During demolding, relative friction is generated between the sidewalls of the first shaping grooves 212 (i.e., the sidewalls extending along the third direction Z) and the fourth outer side surface 152 and the fifth outer side surface 162.

[0115] The fourth outer side surface 152 and the fifth outer side surface 162 are both provided with the first surface roughness, which is relatively flat and smooth, and can reduce the friction between them and the first mold 21, thereby facilitating demolding and preventing the lower plastic 10 from being pulled and deformed by the first mold 21, resulting in a decrease in product yield.

[0116] Optionally, referring to Figures 2, 3, and 7, both the first pole boss 15 and the second pole boss 16 are recessed relative to the second surface 112, so that the first pole boss 15 encloses a first pole groove 153, and the second pole boss 16 encloses a second pole groove 163. The sidewall of the first pole groove 153 is a fourth inner sidewall 154, and the sidewall of the second pole groove 163 is a fifth inner sidewall 164. Both the fourth inner sidewall 154 and the fifth inner sidewall 164 have a first surface roughness.

[0117] 4 and 5 , during injection molding, the plurality of raised structures on the second shaping surface 221 of the second mold 22 are used to form the first and second pole slots 153, 163. During demolding, relative friction is generated between the outer surfaces of the raised structures of the second mold 22 (i.e., the outer surfaces extending along the third direction Z) and the fourth and fifth inner sidewalls 154, 164.

[0118] The fourth inner sidewall 154 and the fifth inner sidewall 164 are both provided with the first surface roughness, which is relatively flat and smooth, and can reduce the friction between them and the second mold 22 , thereby facilitating demoulding and preventing the lower plastic 10 from being pulled and deformed by the second mold 22 and causing a decrease in product yield.

[0119] 3 and 7 , the bottom wall of the first pole slot 153 is a fourth bottom wall 155, and the bottom wall of the second pole slot 163 is a fifth bottom wall 165. Both the fourth bottom wall 155 and the fifth bottom wall 165 have a first surface roughness.

[0120] 2 and 3 , the first terminal boss 15 defines a first terminal hole 156 extending through the fourth top surface 151 and the fourth bottom wall 155, and the second terminal boss 16 defines a second terminal hole 166 extending through the fifth top surface 161 and the fifth bottom wall 165. To reasonably control dimensions and ensure the structural strength of the lower plastic 10, the first and second terminal holes 156, 166 are relatively large. In other words, the fourth and fifth bottom walls 155, 165 are substantially annular in shape and occupy a relatively small area, making them easier to separate from the second mold 22 during demolding. On this basis, the fourth bottom wall 155 and the fifth bottom wall 165 are set to the surface roughness of the first surface 111, which does not cause difficulty in demolding or deformation of the lower plastic 10. In addition, the relatively flat and smooth fourth bottom wall 155 and the fifth bottom wall 165 can more closely adhere to the first plate of the first pole and the fifth bottom wall 165 can more closely adhere to the second plate of the second pole when installing the first pole and the second pole, thereby improving the connection stability.

[0121] 2 and 6 , the top surface of the anti-rotation post 17 protruding from the first surface 111 is a sixth top surface 171, and the outer circumferential surface of the anti-rotation post 17 connects the first surface 111 and the sixth top surface 171. The outer circumferential surface of the anti-rotation post 17 has a first surface roughness, and the sixth top surface 171 has a second surface roughness.

[0122] The outer peripheral surface of the anti-rotation column 17 extends substantially along the third direction Z.

[0123] 4 and 5 , during injection molding, the sidewalls of the first shaping groove 212 on the first shaping surface 211 of the first mold 21 also serve to form the outer circumference of the anti-rotation post 17. During demolding, relative friction is generated between the sidewalls of the first shaping groove 212 (i.e., the sidewalls extending along the third direction Z) and the outer circumference of the anti-rotation post 17.

[0124] The outer peripheral surface of the anti-rotation column 17 has a first surface roughness, which is relatively flat and smooth, and can reduce the friction between the first mold 21, thereby facilitating demoulding and preventing the lower plastic 10 from being pulled and deformed by the first mold 21, resulting in a decrease in product yield.

[0125] In addition, the radial dimension of the anti-rotation column 17 is small, that is, the area of ​​the sixth top surface 171 is small. The sixth top surface 171 is set to have a second surface roughness, which is relatively rough and can facilitate demolding without using a push rod to push the sixth top surface 171.

[0126] In summary, most of the corresponding two surfaces of the lower plastic 10 have different surface roughnesses. For example, the first surface 111 has a first surface roughness, and the corresponding second surface 112 has a second surface roughness; the second bottom wall 135 has a first surface roughness, and the corresponding second top surface 131 has a second surface roughness; the third bottom wall 145 has a first surface roughness, and the corresponding third top surface 141 has a second surface roughness; the fourth bottom wall 155 has a first surface roughness, and the corresponding fourth top surface 151 has a second surface roughness; and the fifth bottom wall 165 has a first surface roughness, and the corresponding fifth top surface 161 has a second surface roughness.

[0127] A small number of corresponding surfaces have the same surface roughness, for example, the first bottom wall and the first top surface both have the second surface roughness.

[0128] With this arrangement, the surface of the lower plastic 10 facing the top cover (i.e., the first surface 111, the third bottom wall 145, the fourth bottom wall 155, and the fifth bottom wall 165) is flatter and smoother than the surface facing away from the top cover. This allows the electrolyte to flow more easily and fall back into the battery cell assembly. Furthermore, during injection molding and demolding, the second mold 22 is easier to separate from the lower plastic 10 than the first mold 21, preventing the movement of the second mold 22 from causing movement of the lower plastic 10 and causing local deformation.

[0129] In addition, the outer side surface and inner side wall of each protrusion structure are set to the first surface roughness, which can reduce the friction between the mold and the lower plastic 10 during demolding and improve the demolding efficiency.

[0130] 6 , the first surface 111 has a micro texture 18. The micro texture 18 extends along the length or width of the body 11, and the protrusion or depression of the micro texture 18 relative to the first surface 111 is 0.01 mm to 0.05 mm.

[0131] The microtexture 18 can be a linearly extending protrusion or groove relative to the first surface 111. The microtexture 18 is formed by microstructures on the first shaping surface 211 of the first mold 21 shown in Figures 4 and 5. The microtexture 18 can guide electrolyte remaining on the first surface 111, causing it to flow along the direction of the microtexture 18, rapidly directing the electrolyte on the first surface 111 to the edges of the first surface 111 and into the battery cell assembly. When the microtexture 18 extends along the length of the body 11, the electrolyte, guided by the microtexture 18, flows along the length of the body 11, into the first and second sinks 133 and 143, and further through the first and second leakage holes 136 and 146 to the battery cell assembly. When the microtexture 18 extends along the width of the body 11, the electrolyte, guided by the microtexture 18, flows along the width of the body 11, leaving the electrolyte at the widthwise edges of the first surface 111 and into the battery cell assembly.

[0132] There can be multiple microtextures 18, each extending in the same direction. It should be understood that for the same lower plastic 10, the microtextures 18 provided on its first surface 111 extend in only one direction, namely, along the length or width of the body 11. Microtextures 18 cannot extend along both the length and width of the body 11 to avoid electrolyte retention at the intersection of microtextures 18 in different directions.

[0133] The protrusion or depression of the microtexture 18 relative to the first surface 111 can be, for example, 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm, or 0.05 mm, without limitation. The protrusion or depression of the microtexture 18 relative to the first surface 111 is small and negligible relative to the thickness of the body 11 (i.e., the dimension in the third direction Z), and has no effect on the structural strength of the body 11.

[0134] In one embodiment, referring to FIG. 2 and FIG. 3 , the lower plastic 10 is bent along the width direction (ie, the second direction Y), and both ends of the lower plastic 10 in the width direction are arranged farther away from the top cover than the middle portion of the lower plastic 10 in the width direction.

[0135] During the installation process of the lower plastic 10 to form the energy storage device 1000, a protective film is hot-melted on the two opposite side surfaces of the explosion-proof sink 12 along the width direction of the main body 11 (i.e., the second direction Y). Under the dual effects of gravity and the pulling force of the protective film, the elasticity and strength of the lower plastic 10 of the energy storage device 1000 decrease after long-term use, causing the two ends of the lower plastic 10 along the second direction Y to sag slightly, that is, the two ends of the lower plastic 10 along the second direction Y sag toward the side of the battery cell assembly, and compared to when it is just installed, the two ends of the lower plastic 10 along the second direction Y are farther away from the top cover. For example, when it is just installed, the upper surface of the lower plastic 10 (i.e., each surface on the side of the first surface 111) and the lower surface of the top cover (i.e., the surface of the top cover facing the battery cell assembly) are in close contact at all places. After a period of use, a gap will be formed between the two ends of the lower plastic 10 along the second direction Y and the lower surface of the top cover.

[0136] The lower plastic 10 is curved along the second direction Y, and the ends of the lower plastic 10 in the width direction are positioned farther away from the top cover than the middle portion of the lower plastic 10 in the width direction. This accelerates the flow of the electrolyte on the first surface 111 and prevents the electrolyte from adhering to the gap between the first surface 111 of the lower plastic 10 and the lower surface of the top cover due to surface tension, thereby preventing it from flowing back.

[0137] Referring to Figure 3, the lower plastic 10 also includes a plurality of connecting ribs 19, which are arranged at the edge of the second surface 112 in the width direction of the main body 11, wherein the two ends of two connecting ribs 19 are respectively connected to the explosion-proof sink 12 and the first sink 13, and the other two ends of the connecting ribs 19 are respectively connected to the explosion-proof sink 12 and the second sink 14. The thickness of the connecting rib 19 (i.e., the dimension along the second direction Y) is small and can be ignored relative to the width of the main body 11 (i.e., the dimension along the second direction Y). The connecting rib 19 is used to strengthen the structural strength of the edge of the width direction of the main body 11 to prevent bending and deformation at the edge. The height of the connecting rib 19 relative to the second surface 112 is also small, much lower than the height of the explosion-proof sink 12, the first sink 13, and the second sink 14 relative to the second surface 112. Therefore, the connecting rib 19 can be easily demolded, and there is no requirement for the surface roughness of the surface of the connecting rib 19, that is, the surface of the connecting rib 19 can be the aforementioned first surface roughness or second surface roughness without restriction.

[0138] Other structures may also be provided on the lower plastic 10 of the embodiment of the present application, such as liquid injection avoidance holes, buckles, coding structures, push points, etc., which are not limited in the present application.

[0139] In the description of the embodiments of the present application, it should be noted that the orientation or positional relationship of terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", and "outside" are based on the orientation or positional relationship described in the accompanying drawings. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present application.

[0140] The above disclosure is only a preferred embodiment of the present application, and certainly cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made in accordance with the claims of the present application are still within the scope covered by the present application.

Claims

1. A lower plastic, used for an end cap assembly of an energy storage device, wherein: include: The body comprises a first surface and a second surface facing each other, wherein the first surface is arranged on a side facing the top cover; an explosion-proof sunken platform, which is arranged in the middle of the length direction of the body and protrudes relative to the second surface; the top surface of the explosion-proof sunken platform protruding from the second surface is a first top surface; the explosion-proof sunken platform is recessed relative to the first surface so that the explosion-proof sunken platform encloses a gas collecting trough, and the bottom wall of the gas collecting trough is a first bottom wall; a first sunken platform, disposed at one end of the body in the longitudinal direction and protruding relative to the second surface; a top surface of the first sunken platform protruding from the second surface being a second top surface; and a first sunken platform being recessed relative to the first surface so as to enclose a first sunken groove, wherein a bottom wall of the first sunken groove being a second bottom wall; a second sunken platform, disposed at an end of the body in the longitudinal direction away from the first sunken platform and protruding relative to the second surface; a top surface of the second sunken platform protruding from the second surface being a third top surface; and a second sunken platform being recessed relative to the first surface so as to enclose a second sunken groove, wherein a bottom wall of the second sunken groove is a third bottom wall; A first pole boss is provided on the body and is located between the explosion-proof sunken platform and the first sunken platform. The first pole boss is raised relative to the first surface. The top surface of the first pole boss protruding from the first surface is a fourth top surface. The first pole boss is recessed relative to the second surface so that the first pole boss encloses a first pole groove. The bottom wall of the first pole groove is a fourth bottom wall. A second pole boss is provided on the body and is located between the explosion-proof sunken platform and the second sunken platform. The second pole boss is raised relative to the first surface. The top surface of the second pole boss protruding from the first surface is a fifth top surface. The second pole boss is recessed relative to the second surface so that the second pole boss encloses a second pole groove. The bottom wall of the second pole groove is a fifth bottom wall. Among them, the first surface, the second bottom wall, the third bottom wall, the fourth bottom wall and the fifth bottom wall all have a first surface roughness, the second surface, the first bottom wall, the first top surface, the second top surface, the third top surface, the fourth top surface and the fifth top surface all have a second surface roughness, the first surface roughness is A, the second surface roughness is B, and the following is satisfied: A<B.

2. The lower plastic according to claim 1, wherein: The first surface roughness and the second surface roughness further satisfy: Ra0.02≤A≤Ra1.6, Ra0.8≤B≤Ra12.

5.

3. The lower plastic according to claim 1, wherein: The explosion-proof sink includes a first boss and two second bosses, the first boss is arranged in the middle of the width direction of the body, and the first boss is connected to a second boss at each end of the width direction of the body. The height of the first boss relative to the second surface is less than the height of the second boss relative to the second surface. The first top surface includes a first sub-top surface and a second sub-top surface. The top surface of the first boss protruding from the second surface is the first sub-top surface, and the top surface of the second boss protruding from the second surface is the second sub-top surface. The first sub-top surface and the second sub-top surface both have the second surface roughness.

4. The lower plastic according to claim 3, wherein: The first bottom wall includes a first sub-bottom wall and a second sub-bottom wall; the depth of the first boss relative to the first surface is smaller than the depth of the second boss relative to the first surface, the bottom wall of the gas collecting groove corresponding to the first boss is the first sub-bottom wall, and the bottom wall of the gas collecting groove corresponding to the second boss is the second sub-bottom wall, and both the first sub-bottom wall and the second sub-bottom wall have the second surface roughness.

5. The lower plastic according to claim 1, wherein: The explosion-proof sink has a first outer side surface, the first sink has a second outer side surface, the second sink has a third outer side surface, the first outer side surface connects the second surface and the first top surface, the second outer side surface connects the second surface and the second top surface, the third outer side surface connects the second surface and the third top surface, and the first outer side surface, the second outer side surface and the third outer side surface have the first surface roughness.

6. The lower plastic according to claim 1, wherein: The side wall of the gas collecting groove is the first inner side wall, the side wall of the first trough is the second inner side wall, and the side wall of the second trough is the third inner side wall. The first inner side wall, the second inner side wall and the third inner side wall are all connected to the first surface, and the first inner side wall, the second inner side wall and the third inner side wall all have the first surface roughness.

7. The lower plastic according to claim 1, wherein: The lower plastic also includes a plurality of first reinforcing ribs and a plurality of second reinforcing ribs. The plurality of first reinforcing ribs and the plurality of second reinforcing ribs extend along the length direction of the body and are spaced apart in the width direction of the body. Each of the first reinforcing ribs connects two opposite side walls and a bottom wall of the first sink in the length direction of the body. Each of the second reinforcing ribs connects two opposite side walls and a bottom wall of the second sink in the length direction of the body. The first reinforcing rib has a third surface, and the second reinforcing rib has a fourth surface. The third surface and the fourth surface are both flush with the first surface, and the third surface and the fourth surface have the second surface roughness.

8. The lower plastic according to claim 7, wherein: The dimensions of the first reinforcing rib and the second reinforcing rib in the width direction of the main body are both 0.85mm-3.65mm, the second top surface has a first groove at a position corresponding to the first reinforcing rib, and the third top surface has a second groove at a position corresponding to the second reinforcing rib. The first groove is recessed from the second top surface and passes through the two opposite outer side surfaces of the first sink along the length direction of the main body, and the second groove is recessed from the third top surface and passes through the two opposite outer side surfaces of the second sink along the length direction of the main body.

9. The lower plastic according to claim 1, wherein: The first pole boss has a fourth outer side surface, the second pole boss has a fifth outer side surface, the fourth outer side surface connects the first surface and the fourth top surface, the fifth outer side surface connects the first surface and the fifth top surface, and both the fourth outer side surface and the fifth outer side surface have the first surface roughness.

10. The lower plastic according to claim 1, wherein: The sidewall of the first pole slot is a fourth inner sidewall, and the sidewall of the second pole slot is a fifth inner sidewall. Both the fourth inner sidewall and the fifth inner sidewall have the first surface roughness.

11. The lower plastic according to claim 1, wherein: The lower plastic also includes an anti-rotation column, which is connected to the body and protrudes from the first surface. The top surface of the anti-rotation column protruding from the first surface is a sixth top surface. The outer peripheral surface of the anti-rotation column connects the first surface and the sixth top surface. The outer peripheral surface of the anti-rotation column has the first surface roughness, and the sixth top surface has the second surface roughness.

12. The lower plastic according to claim 1, wherein: The first surface has a micro texture, the micro texture extends along the length direction or the width direction of the body, and the size of the micro texture protruding or recessed relative to the first surface is 0.01mm-0.05mm.

13. The lower plastic according to claim 1, wherein: The lower plastic is bent along a width direction, and both ends of the lower plastic in the width direction are arranged to be farther away from the top cover than a middle portion of the lower plastic in the width direction.

14. An end cap assembly, wherein: It comprises a top cover and the lower plastic according to any one of claims 1 to 13, wherein the first surface of the lower plastic faces the top cover.

15. An energy storage device, wherein: It comprises a shell, a battery cell assembly and the end cover assembly as claimed in claim 14, wherein the battery cell assembly is arranged in the shell, and the end cover assembly is connected to the shell.

16. An electrical device, wherein: It comprises an electric device and the energy storage device as claimed in claim 15, wherein the energy storage device supplies power to the electric device.

Images