CN116799391B

CN116799391B - Lower plastic, energy storage device and electric equipment

Info

Publication number: CN116799391B
Application number: CN202311096407.4A
Authority: CN
Inventors: 李茂松
Original assignee: Shenzhen Haichen Energy Storage Control Technology Co ltd; Xiamen Hithium Energy Storage Technology Co Ltd
Current assignee: Shenzhen Haichen Energy Storage Control Technology Co ltd; Xiamen Hithium Energy Storage Technology Co Ltd
Priority date: 2023-08-29
Filing date: 2023-08-29
Publication date: 2023-12-26
Anticipated expiration: 2043-08-29
Also published as: CN116799391A

Abstract

The application discloses plastic, energy memory and consumer down, the plastic includes plastic body and recess down, and the plastic body has first surface and the second surface that set up dorsad along the thickness direction of plastic down. The groove is recessed from the first surface to the second surface and protrudes out of the second surface, and comprises a first groove side wall and a second groove side wall which are oppositely arranged, and a groove bottom wall which is connected with the first groove side wall and the second groove side wall. The through hole is arranged on the bottom wall of the groove, and penetrates through the bottom wall of the groove along the thickness direction of the lower plastic. The first groove side wall is provided with an opening at one end far away from the groove bottom wall, the opening penetrates through the first groove side wall, and the opening extends towards one side of the lower plastic body and penetrates through the first surface and the second surface. According to the method, electrolyte inside the lower plastic can smoothly flow back to the pole piece, and the backflow efficiency and the use efficiency of the electrolyte are improved.

Description

Lower plastic, energy storage device and electric equipment

Technical Field

The application relates to the technical field of energy storage, in particular to lower plastic, an energy storage device and electric equipment.

Background

The secondary battery (Rechargeable battery) is also called a rechargeable battery or a storage battery, and is a battery that can be continuously used by activating an active material by charging after discharging the battery. The recyclable characteristic of the secondary battery gradually becomes a main power source of electric equipment, as the demand of the secondary battery is gradually increased, the performance requirements of people on all aspects of the secondary battery are also higher and higher, especially the requirement on the light weight of the secondary battery is met, the capacity and the cycle life of the energy storage device are greatly influenced by reducing the weight of the coiled electrode assembly, for example, the capacity is reduced by reducing the weight of positive and negative active materials, the structure of the current collector is unstable due to the weight (thinning) of the current collector, and the cycle life is reduced; therefore, weight reduction of the end cap assembly is a key to weight reduction of the secondary battery.

In the existing secondary battery, the positive and negative electrode posts are electrically connected with the positive and negative electrode lugs of the winding electrode assembly through the switching sheet, so that a step is required to be designed at two ends of the lower plastic part in the length direction so as to support the positive and negative electrode posts and the winding electrode assembly to form a certain gap for accommodating the switching sheet and the electrode lugs; the step protruding out of the large plane of the lower plastic body needs more plastic materials to be formed, so that the weight of the secondary battery is increased, and the material cost is increased.

Disclosure of Invention

The utility model provides a plastic, energy memory and consumer down can make the electrolyte that splashes to the plastic inside down flow back to the utmost point core smoothly, improves the backward flow efficiency of electrolyte to improve the availability factor of electrolyte.

The lower plastic is used for an energy storage device, and comprises: the lower plastic body is provided with a first surface and a second surface, and the first surface and the second surface are arranged back to back along the thickness direction of the lower plastic; the groove is recessed from the first surface to the second surface and protrudes out of the second surface, the groove comprises a first groove side wall and a second groove side wall which are oppositely arranged, and a groove bottom wall which is connected with the first groove side wall and the second groove side wall, the groove bottom wall is provided with a through hole, the through hole penetrates through the groove bottom wall along the thickness direction of the lower plastic, and one end of the first groove side wall, which is far away from the groove bottom wall, is connected with one end of the lower plastic body in the length direction; the first groove side wall is provided with an opening at one end far away from the groove bottom wall, the opening penetrates through the first groove side wall, and the opening extends towards one side of the lower plastic body and penetrates through the first surface and the second surface.

In one embodiment, the lower plastic body further comprises a post through hole, wherein the post through hole is arranged at intervals with the groove and is positioned at one side of the lower plastic body close to the groove; the lower plastic comprises a reinforcing rib, the reinforcing rib is located in the groove and is convexly arranged on the bottom wall of the groove, the reinforcing rib extends along the length direction of the lower plastic and is connected with the side wall of the first groove and the side wall of the second groove, the groove is divided into a plurality of sub grooves, and each sub groove is correspondingly provided with a through hole and an opening.

In one embodiment, the plurality of openings are symmetrical along a central line along a length direction of the lower plastic, and each opening is disposed at an end of the sidewall of the first groove away from the central line.

In one embodiment, the groove further comprises a first groove end wall and a second groove end wall which are oppositely arranged, the first groove end wall and the second groove end wall are connected with the first groove side wall, the second groove side wall and the groove bottom wall, and the first groove end wall, the second groove end wall, the first groove side wall and the second groove side wall are obliquely arranged relative to a central line in the thickness direction of the groove; the cross section of the groove is isosceles trapezoid along the central line of the lower plastic in the length direction and the central line of the groove in the width direction, and the bottom wall of the groove is the short side of the isosceles trapezoid.

In one embodiment, the end surface of the rib remote from the bottom wall of the groove is flush with the first surface.

In one embodiment, the diameter of the through hole is 1.15mm to 1.55mm.

In one embodiment, the opening is rectangular.

In one embodiment, the lower plastic further comprises an explosion-proof fence, wherein the explosion-proof fence is positioned in the middle of the lower plastic body and protrudes out of the second surface; the explosion-proof fence comprises a first part, a second part and a third part, wherein the second part and the third part are connected with the first part and are positioned on two opposite sides of the first part in the width direction; the first part comprises a first outer surface, the first outer surface protrudes out of the second surface, and a height difference H1 exists between the first outer surface and the second surface along the thickness direction of the lower plastic; the second part comprises a second outer surface, the second outer surface protrudes out of the second surface, and a height difference H2 exists between the second outer surface and the second surface along the thickness direction of the lower plastic, and H1 is more than H2; the third part comprises a third outer surface, the third outer surface protrudes out of the second surface, a height difference H3 exists between the second outer surface and the second surface along the thickness direction of the lower plastic, and H1 is more than H3; the first outer surface, the second outer surface and the third outer surface are provided with a plurality of diversion holes; the plurality of diversion holes penetrate through the first part, the second part and the third part along the thickness direction of the lower plastic.

In one embodiment, the length of the second portion and the third portion is smaller than the length of the first portion along the width direction of the lower plastic; the lower plastic further comprises a through groove which is arranged opposite to the explosion-proof fence, the through groove is used for installing an explosion-proof valve, and the lengths of the second part and the third part are greater than the length of the explosion-proof valve along the width direction of the lower plastic.

The application also provides an energy storage device which comprises a pole, a flange arranged at one end of the pole, an adapter, a winding type electrode assembly and lower plastic as described above; the lower plastic comprises a concave part concavely arranged on the second surface, the pole penetrates through the lower plastic, the flange is accommodated in the concave part, and the flange protrudes out of the second surface; the adapter is connected with the flange and the winding electrode assembly, and the flange and the winding electrode assembly are positioned on two opposite sides of the adapter.

In one embodiment, the energy storage device comprises an insulating film, the insulating film comprises an upper surface and a lower surface which are arranged back to each other, the lower surface is connected to one side of the adapter, which is opposite to the winding type electrode assembly, and a gap is reserved between the upper surface and the second surface.

The application also provides electric equipment, which comprises the energy storage device, wherein the energy storage device is used for storing electric energy.

Drawings

In order to more clearly illustrate the technical solutions of the present application, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained by those skilled in the art without the inventive effort.

Fig. 1 is an application scenario diagram of an energy storage device provided in an embodiment of the present application;

FIG. 2 is a schematic perspective view of the energy storage device shown in FIG. 1;

FIG. 3 is an exploded view of the energy storage device of FIG. 2;

FIG. 4 is an exploded view of a portion of the energy storage device shown in FIG. 2;

FIG. 5 is an exploded view of a portion of the energy storage device of FIG. 2 at another angle;

FIG. 6 is a schematic view of the lower plastic shown in FIG. 3;

FIG. 7 is a schematic view of the lower plastic shown in FIG. 4;

FIG. 8 is an enlarged view of a portion of the lower plastic at A shown in FIG. 6;

fig. 9 is a schematic view of a portion of the energy storage device shown in fig. 2 taken along line A-A.

The corresponding nouns of the reference numerals in the figures are: 5000 energy storage system, 4500 electric energy conversion device, 4000 wind energy conversion device, 3000 first user load, 1000 energy storage device, 400 case, 100 end cap assembly, 200 wound electrode assembly, 210 pole, 220 first pole ear, 230 second pole ear, 310 first adapter, 311 first body, 312 first adapter, 313 second adapter, 320 second adapter, 321 second body, 322 third adapter, 323 fourth adapter, 331 first insulation film, 3311 first insulation portion, 3312 second insulation portion, 3312a second section, 3313 third insulation portion, 3313a third section, 332 second insulation film, 3321 fourth insulation portion, 3322 fifth insulation portion, 3322a fifth section, 3323 sixth insulation portion, 3323a sixth section, 50 first pole, 51 first flange, 60 second pole, 61 second flange, 40 top cover, 41 body, 411 front face, 412 back face, 413 first mounting groove, 414 second mounting groove, 42 first mounting hole, 43 second mounting hole, 44 explosion-proof valve, 441 explosion-proof valve protection sheet, 45 sealing plug, 46 filling hole, 47 through slot, 10 lower plastic, 11 lower plastic body, 111 first surface, 112 second surface, 12 first post through hole, 13 first recess, 131 first holding protrusion, 14 second post through hole, 15 second recess, 151 second holding protrusion, 16 first protrusion, 16A first recess, 160a first end wall, 160b second end wall, 161 first side wall, 162 second side wall, 163 first bottom wall, 164 first reinforcing rib, 165 first sub-recess, 1651 first slot side wall, 1652 second slot side wall, 1653 first slot bottom wall, 166 first through hole, 167 first opening, 17 second protrusion, 17A second recess, 170a third end wall, 170b fourth end wall, 171 third side wall, 172 fourth side wall, 173 second bottom wall, 174 second reinforcing rib, 175 second sub-recess, 1751 third slot side wall, 1752 fourth slot sidewall, 1753 second slot bottom wall, 176 second through hole, 177 second opening, 18 explosion proof fence, 18A groove portion, 180 deflector hole, 181 first portion, 1811 first fence sidewall, 1812 second fence sidewall, 1813 first fence bottom wall, 1813a first outer surface, 1813b first inner surface, 182 second portion, 1821 third fence sidewall, 1822 second fence bottom wall, 1822a second outer surface, 1822b second inner surface, 183 third portion, 1831 fourth fence sidewall, 1832 third fence bottom wall, 1832a third outer surface, 1832b third inner surface, 1814 first notch, 1815 first inner wall, 1816 second notch, 1817 second inner wall.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

Because of the strong timeliness and space properties of energy required by people, in order to reasonably utilize the energy and improve the utilization rate of the energy, one energy form needs to be stored by one medium or equipment and then converted into another energy form, and the energy is released in a specific energy form based on future application. As is well known, to achieve the great goal of carbon neutralization, the main approach to green electric energy generation is to develop green energy sources such as photovoltaic, wind power and the like to replace fossil energy sources. At present, the generation of green electric energy generally depends on photovoltaic, wind power, water potential and the like, but wind energy, solar energy and the like generally have the problems of strong intermittence and large fluctuation, which can cause unstable power grid, insufficient peak electricity consumption, too much electricity consumption and unstable voltage can cause damage to the electric power, so that the problem of 'wind abandoning and light abandoning' possibly occurs due to insufficient electricity consumption requirement or insufficient power grid acceptance, and the problem needs to be solved by relying on energy storage. The energy is converted into other forms of energy through physical or chemical means and is stored, the energy is converted into electric energy when needed and released, in short, the energy storage is similar to a large-scale 'charge pal', the electric energy is stored when the photovoltaic and wind energy are sufficient, and the stored electric power is released when needed.

Taking electrochemical energy storage as an example, the scheme provides an energy storage device, wherein a group of chemical batteries are arranged in the energy storage device, chemical elements in the chemical batteries are mainly used as energy storage media, and the charge and discharge process is accompanied with chemical reaction or change of the energy storage media.

The existing energy storage (i.e. energy storage) application scene is wider, including aspects such as (wind and light) power generation side energy storage, electric network side energy storage, base station side energy storage and user side energy storage, the types of corresponding energy storage devices include:

(1) The large energy storage container applied to the energy storage scene at the power grid side can be used as a high-quality active and reactive power regulation power supply in the power grid, so that the load matching of electric energy in time and space is realized, the renewable energy consumption capability is enhanced, and the large energy storage container has great significance in the aspects of standby of a power grid system, relieving peak load power supply pressure and peak regulation and frequency modulation;

(2) The small and medium energy storage electric cabinet is applied to industrial and commercial energy storage scenes (banks, markets and the like) at the user side, and the main operation mode is peak clipping and valley filling. Because of the large price difference of the electricity charge at the peak-valley position according to the electricity consumption requirement, after the energy storage equipment is arranged by a user, in order to reduce the cost, the energy storage cabinet/box is charged usually in the electricity price valley period; and in the peak period of electricity price, the electricity in the energy storage equipment is released for use, so that the purpose of saving electricity charge is achieved.

Referring to fig. 1, fig. 1 is an application scenario diagram of an energy storage device 1000 provided in an embodiment of the present application, and in the embodiment of the present application, a home energy storage scenario in user side energy storage is taken as an example for illustration, and the energy storage device 1000 is not limited to the home energy storage scenario.

The application provides a household energy storage system 5000, this household energy storage system 5000 includes electric energy conversion device 4500 (photovoltaic board), wind energy conversion device 4000 (windmill), first user load 3000 (basic station), second user load (not shown) (business side) etc. and energy storage device 1000, and energy storage system still includes the energy storage cabinet, and this energy storage device 1000 is adorned in the energy storage cabinet, is convenient for install outdoor. In particular, the power conversion device 4500 may convert solar energy into electric energy during low electricity price period, and the energy storage device 1000 is used to store the electric energy and supply the electric energy to a base station and a commercial side for use during peak electricity price period, or supply the electric power during power outage/power failure of the electric network. Wind energy conversion device 4000 (windmill) can convert wind energy into electric energy, and energy storage device 1000 is used for storing the electric energy and supplying the electric energy to a base station and a business side for use at the time of peak electricity price or supplying power at the time of power failure/power outage of a power grid. The transmission of the electric energy can be performed by adopting a high-voltage cable.

It is understood that the energy storage device 1000 may include, but is not limited to, a battery cell, a battery module, a battery pack, a battery system, etc. The practical application form of the energy storage device 1000 provided in the embodiment of the present application may be, but is not limited to, the listed products, and may also be other application forms, and the embodiment of the present application does not strictly limit the application form of the energy storage device 1000. The number of the energy storage devices 1000 may be plural, and the energy storage devices 1000 may be connected in series or parallel to each other, and the energy storage devices 1000 are supported and electrically connected by using a separator (not shown). In the present embodiment, "a plurality of" means two or more.

The embodiment of the present application will be described by taking the energy storage device 1000 as a multi-core battery as an example.

Referring to fig. 2 to 4, the energy storage device 1000 includes a case 400, an end cap assembly 100, a rolled electrode assembly 200, a first adapter 310 and a second adapter 320, wherein the end cap assembly 100 is mounted at one end of the rolled electrode assembly 200, and the case 400 has an opening and is provided with a receiving cavity; the rolled electrode assembly 200 is received in the receiving chamber, and the cap assembly 100 is sealed to the opening. Wherein the first adapter 310 connects the rolled electrode assembly 200 and the first post 50 of the end cap assembly 100, and the second adapter 320 connects the rolled electrode assembly 200 and the second post 60 of the end cap assembly 100.

For convenience of description, the length direction of the end cap assembly 100 shown in fig. 2 is defined as an X-axis direction, the width direction of the end cap assembly 100 is defined as a Y-axis direction, the thickness direction of the end cap assembly 100 is defined as a Z-axis direction, and the X-axis direction, the Y-axis direction and the Z-axis direction are perpendicular to each other. The terms "upper" and "lower" and the like in the description of the embodiments of the present application are described according to the orientation shown in fig. 2 of the specification, and are not limited to the energy storage device 1000 in the practical application scenario, and are "up" toward the positive Z-axis direction and "down" toward the negative Z-axis direction. The use of "identical", "equal" or "parallel" in the following allows for certain tolerances.

In this embodiment, the rolled electrode assembly 200 includes two electrode cores 210. Along the width direction (Y-axis direction) of the energy storage device 1000, two pole pieces 210 are arranged side by side. Each of the pole pieces 210 includes a first pole tab 220 and a second pole tab 230. Along the width direction (X-axis direction) of the energy storage device 1000, the first tabs 220 of the two pole cores 210 are disposed respectively, and the second tabs 230 are disposed respectively. The first tab 220 of the two pole cores 210 is connected to the first pole 50 through the first adapter 310, and the second tab 230 of the two pole cores 210 is connected to the second pole 60 through the second adapter 320.

In this embodiment, the outside of the coiled electrode assembly 200 is further covered with an insulating film (not shown) for protecting the electrode core 210 from being scratched. The insulating film is coated on the outer surface of the rolled electrode assembly 200, and the side edges of the insulating film are thermally fusion-bonded with the end cap assembly 100.

Referring to fig. 4 and 5, the end cap assembly 100 includes a lower plastic 10 and a top cap 40, the lower plastic 10 is mounted on the top cap 40, and the lower plastic 10 is located between the rolled electrode assembly 200 and the top cap 40. The top cover 40 in this embodiment is an aluminum light member, and the lower plastic 10 is made of plastic material and is insulated.

In this embodiment, the cap 40 includes a cap body 41, an explosion-proof valve 44, and a sealing plug 45. The cap body 41 includes a liquid injection hole 46 and two through holes. Specifically, the two through holes are a first mounting hole 42 and a second mounting hole 43, respectively. The first mounting hole 42, the liquid injection hole 46, the explosion-proof valve 44, and the second mounting hole 43 are sequentially arranged at intervals along the X-axis direction, that is, the length direction of the top cover 40. Specifically, the top cover body 41 is a strip-shaped thin plate, and includes a front surface 411 and a back surface 412 disposed opposite to the front surface 411 along the thickness direction (Z-axis direction) of the top cover body 41. The top cover body 41 further includes first and second mounting grooves 413 and 414, the first and second mounting grooves 413 and 414 being located at opposite end positions (aligned along the X-axis direction) of the back surface 412 of the top cover body 41. The first mounting groove 413 and the second mounting groove 414 are rectangular grooves, and the first mounting groove 413 is formed by recessing the back surface 412 toward the front surface 411. The second mounting groove 414 is formed by recessing the back surface 412 toward the front surface 411. It will be appreciated that the first mounting groove 413 and the second mounting groove 414 are respectively disposed at opposite ends of the top cover body 41 for mating connection with the lower plastic 10. The first mounting hole 42 penetrates the groove bottom wall of the first mounting groove 413, and the second mounting hole 43 penetrates the groove bottom wall of the second mounting groove 414. It will be appreciated that the first and second mounting holes 42 and 43 are provided at opposite ends of the top cover body 41, respectively, for passing the first and second poles 50 and 60 of the battery, respectively.

In this embodiment, the top cover body 41 is further provided with a through slot 47 penetrating the back surface 412 and the front surface 411, and the through slot 47 is located between the first mounting slot 413 and the second mounting slot 414. The through slot 47 is located at the middle position of the top cover body 41. The explosion-proof valve 44 is accommodated in the through groove 47 and welded with the groove wall of the through groove 47. When the pressure in the energy storage device 1000 is too high, the explosion-proof valve 44 will automatically open to release the pressure, so as to prevent explosion. The top cover 40 also includes an explosion proof valve protection tab 441. The explosion-proof valve protection sheet 441 is disposed opposite to the explosion-proof valve 44. The explosion-proof valve protection piece 441 covers the through groove 47 and is flush with the front face 411 of the cap body 41. The liquid filling hole 46 is provided between the first mounting groove 413 and the explosion-proof valve 44, and penetrates the back surface 412 and the front surface 411, and in the liquid filling process of the power battery, the electrolyte is filled into the battery through the liquid filling hole 46 in the top cover 40. The sealing plug 45 is fitted into the liquid filling hole 46 from the front face 411 of the cap body 41 and seals the liquid filling hole 46.

The end cap assembly 100 also includes two pole posts and an upper plastic assembly 70. Specifically, the two poles are a first pole 50 and a second pole 60, respectively. The upper plastic component 70 is fixedly connected to the top cover 40 and is sleeved on the first pole 50 and the second pole 60. Specifically, the upper plastic component 70 includes a first upper plastic 71 and a second upper plastic 72, the first pole 50 is insulated from the top cover 40 by the first upper plastic 71, and the second pole 60 is insulated from the top cover 40 by the second upper plastic 72. One end of each pole is connected with a flange, namely a first flange 51 and a second flange 61. One end of the first pole 50 is connected to a first flange 51, and one end of the second pole 60 is connected to a second flange 61. The first pole 50 is configured to electrically connect with the first adapter 310, and the second pole 60 is configured to electrically connect with the second adapter 320. In the present embodiment, the first tab 220 is a positive tab, the second tab 230 is a negative tab, the first post 50 is a positive post, and the second post 60 is a negative post. The first flange 51 is a positive electrode flange, and the second flange 61 is a negative electrode flange.

The first adaptor 310 is a conductive sheet, and includes a first body 311, a first adaptor 312 and a second adaptor 313, the first adaptor 312 and the second adaptor 313 are rectangular sheets, the first adaptor 312 and the second adaptor 313 are respectively connected to two opposite sides of the first body 311, and the first adaptor 312 and the second adaptor 313 are both far away from the first body 311 and extend parallel to the first body 311. The first body 311, the first adapter 312 and the second adapter 313 may be integrally formed structures, and the first adapter 312 and the second adapter 313 may be symmetrical with respect to a center line of the first body 311 in a length direction of the end cap assembly 100. Wherein, the first body 311 is used for connecting with the first flange 51. The first adapter 312 and the second adapter 313 are used for connecting with the first tabs 220 of the two pole cores 210.

The second adapting piece 320 is a conductive sheet, and includes a second body 321, a third adapting body 322 and a fourth adapting body 323, wherein the third adapting body 322 and the fourth adapting body 323 are rectangular sheets, the third adapting body 322 and the fourth adapting body 323 are respectively connected with two opposite sides of the second body 321, and the third adapting body 322 and the fourth adapting body 323 are far away from the second body 321 and extend parallel to the first body 311. The second body 321, the third adapter 322 and the fourth adapter 323 may be integrally formed structures, and the third adapter 322 and the fourth adapter 323 may be symmetrical with respect to the center line of the second body 321 in the length direction of the end cap assembly 100. Wherein the second body 321 is adapted to be connected to the second flange 61. The third adapter 322 and the fourth adapter 323 are used for connecting with the second lugs 230 of the two pole cores 210.

In this embodiment, the end cap assembly 100 further includes two insulating films, namely a first insulating film 331 and a second insulating film 332. The first insulating film 331 is substantially C-shaped and includes a first insulating portion 3311, a second insulating portion 3312, and a third insulating portion 3313, the second insulating portion 3312 and the third insulating portion 3313 are connected to opposite sides of the first insulating portion 3311, respectively, and the second insulating portion 3312 and the third insulating portion 3313 are both away from the first insulating portion 3311 and extend parallel to the first insulating portion 3311, the second insulating portion 3312 has a second section 3312a, the third insulating portion 3313 has a third section 3313a, and the second section 3312a and the third section 3313a are arranged at intervals and extend in the same direction. The first, second and third insulating portions 3311, 3312, 3313 may be integrally formed structures, and the second and third insulating portions 3312, 3313 may be symmetrical about a centerline of the first insulating portion 3311 in a length direction of the end cap assembly 100.

Along the thickness direction (Z-axis direction) of the end cap assembly 100, the first insulating film 331 includes a first upper surface 3314 (which may be understood as an upper surface of the insulating film) and a first lower surface 3315 (which may be understood as a lower surface of the insulating film) disposed opposite. The first bottom surface 3315 is used to connect to the first adapter 310. Specifically, the first insulating portion 3311 is attached to a surface of the first body 311 facing away from the pole core 210, and covers a portion of the surface of the first body 311; the other portion of the surface of the first body 311 is exposed with respect to the first insulating portion 3311 for connection to the first flange 51. The second insulating portion 3312 is attached to the surface of the first adapting body 312 facing away from the first tab 220, and covers the first adapting body 312. The third insulating portion 3313 is attached to a surface of the second adapter 313 facing away from the first tab 220, and covers the second adapter 313.

The second insulating film 332 is substantially C-shaped and includes a fourth insulating portion 3321, a fifth insulating portion 3322 and a sixth insulating portion 3323, the fifth insulating portion 3322 and the sixth insulating portion 3323 are respectively connected to opposite sides of the fourth insulating portion 3321, and the fifth insulating portion 3322 and the sixth insulating portion 3323 are both far from the fourth insulating portion 3321 and extend parallel to the fourth insulating portion 3321, the fifth insulating portion 3322 has a fifth section 3322a, the sixth insulating portion 3323 has a sixth section 3323a, and the fifth section 3322a and the sixth section 3323a are disposed at intervals and extend in the same direction. The fourth insulating portion 3321, the fifth insulating portion 3322 and the sixth insulating portion 3323 may be integrally formed structures, and the fifth insulating portion 3322 and the sixth insulating portion 3323 may be symmetrical with respect to a center line of the fourth insulating portion 3321 in the length direction of the cap assembly 100.

Along the thickness direction (Z-axis direction) of the end cap assembly 100, the second insulating film 332 includes a second upper surface 3324 (which may be understood as an upper surface of the insulating film) and a second lower surface 3325 (which may be understood as an upper surface of the insulating film) disposed opposite thereto. The second lower surface 3325 is for connecting to the second adapter 320. Specifically, the fourth insulating portion 3321 is attached to a surface of the second body 321 facing away from the pole core 210, and covers a part of the surface of the second body 321; the other part of the surface of the second body 321 is exposed to the fourth insulating portion 3321 for connecting with the second flange 61. The fifth insulating portion 3322 is attached to a surface of the third adapter 322 facing away from the second tab 230, and covers the third adapter 322. The sixth insulating portion 3323 is attached to the surface of the fourth adapter 323 facing away from the second tab 230 and covers the fourth adapter 323.

In this embodiment, the lower plastic 10 includes a lower plastic body 11. The lower plastic body 11 is a substantially rectangular thin plate, and includes a first surface 111 and a second surface 112 along a thickness direction (Z-axis direction) of the lower plastic 10, where the first surface 111 and the second surface 112 are disposed opposite to each other.

In this embodiment, the lower plastic body 11 includes two post through holes and two recesses. The two post through holes are a first post through hole 12 and a second post through hole 14 respectively, and the two recesses are a first recess 13 and a second recess 15 respectively. The first post through hole 12 and the first recess 13 are disposed near one end of the lower plastic body 11. The first pole through hole 12 is used for the first pole 50 to pass through. The first recess 13 is for receiving the first flange 51. The first concave portion 13 is recessed from the second surface 112 toward the first surface 111, and a first holding projection 131 is formed on the first surface 111. The first post through hole 12 is a square through hole, the first post through hole 12 penetrates through the first surface 111 and the second surface 112, and the first post through hole 12 penetrates through the bottom wall of the first recess 13, that is, penetrates through the first clamping protrusion 131.

The second post through hole 14 and the second recess 15 are disposed near the other end of the lower plastic body 11. The second post via 14 is for the second post 60 to pass through. The second recess 15 is for receiving the second flange 61. The second recess 15 is recessed from the second surface 112 toward the first surface 111, and a second retaining protrusion 151 is formed on the first surface 111. The second post through hole 14 is a square through hole, the second post through hole 14 penetrates through the first surface 111 and the second surface 112, and the second post through hole 14 penetrates through the bottom wall of the second concave portion 15, that is, penetrates through the second clamping protrusion 151.

Referring to fig. 6 and 7, the lower plastic 10 includes a first protrusion 16, a second protrusion 17, and an explosion-proof barrier 18. The first protrusion 16 and the second protrusion 17 are respectively protruded at two ends of the lower plastic body 11, and the explosion-proof fence 18 is located in the middle of the lower plastic body 11. Along the length direction (X-axis direction) of the lower plastic body 11, the first protrusions 16, the first post through holes 12, the explosion-proof fence 18, the second post through holes 14, and the second protrusions 17 are sequentially arranged at intervals. In the present embodiment, the first protrusion 16 and the second protrusion 17 protrude from the second surface 112 of the lower plastic body 11, and two grooves, respectively, a first groove 16A and a second groove 17A are formed on the first surface 111 of the lower plastic body 11, and the two grooves are respectively recessed from the first surface 111 toward the second surface 112 and protrude from the second surface 112.

In the present embodiment, the first protrusion 16 is protruding on the second surface 112, and the first groove 16A is formed on the first surface 111. It can be appreciated that the first groove 16A is recessed from the first surface 111 toward the second surface 112 and protrudes from the second surface 112, and the bottom wall of the first groove 16A supports the pole piece 210 below the first groove with a gap for accommodating the first adapter 310 and the first tab 220 connected to each other; in addition, the first groove 16A is internally provided with a cavity, so that the weight of the lower plastic 10 is reduced, and the overall weight of the energy storage device 1000 is further reduced; meanwhile, plastic materials are saved, the structural cost is reduced, and the production cost of the energy storage device 1000 is further reduced.

In this embodiment, the first groove 16A includes a first end wall 160a and a second end wall 160b disposed opposite to each other, a first side wall 161 and a second side wall 162 disposed opposite to each other, and a first bottom wall 163 connecting the first end wall 160a, the second end wall 160b, the first side wall 161 and the second side wall 162, the first end wall 160a and the second end wall 160b connect the first side wall 161 and the second side wall 162, one end of the first side wall 161 away from the first bottom wall 163 connects one end of the lower plastic body 11 in the length direction, that is, the second side wall 162 is located on one side of the first side wall 161 away from the first post through hole 12, that is, the first post through hole 12 is located on one side of the lower plastic body 11 close to the first groove 16A. Wherein the first end wall 160a may be understood as a first groove end wall, the second end wall 160b may be understood as a second groove end wall, the first side wall 161 may be understood as a first groove side wall, the second side wall 162 may be understood as a second groove side wall, and the first bottom wall 163 may be understood as a groove bottom wall.

In the present embodiment, the first end wall 160a, the second end wall 160b, the first side wall 161, and the second side wall 162 are disposed obliquely with respect to the center line in the thickness direction of the first groove 16A. The cross section of the first groove 16A is isosceles trapezoid along the middle line (see the line O-O in fig. 7) of the lower plastic 10 in the length direction and the middle line (see the line O2-O2 in fig. 7) of the first groove 16A in the width direction, and the first bottom wall 163 is the short side of the isosceles trapezoid. It will be appreciated that the peripheral walls of the first recess 16A (i.e., the first end wall 160a, the second end wall 160b, the first side wall 161, the second side wall 162) are sloped to guide the electrolyte to accelerate toward the first through hole 166; the demolding resistance of the molding area of the first groove 16A can be reduced, so that the movable mold, namely the mold provided with one surface inserted into the protruding block of the first groove 16A can be demolded upwards when the lower plastic 10 is subjected to injection molding.

The first bottom wall 163 is provided with a first through hole 166 (i.e., the bottom wall of the groove is provided with a through hole), and the first through hole 166 penetrates through the first bottom wall 163 along the thickness direction of the lower plastic 10. The number of the first through holes 166 may be plural, and the plural first through holes 166 are arranged at intervals along the width direction (Y-axis direction) of the lower plastic 10. In the use process of the energy storage device 1000, if the energy storage device 1000 shakes to cause the electrolyte to splash into the first groove 16A, the electrolyte can flow back to the pole core 210 through the first through hole 166, which is beneficial to improving the backflow efficiency of the electrolyte, thereby improving the use efficiency of the electrolyte.

In the present embodiment, the diameter of the first through hole 166 is 1.15 mm-1.55 mm; specifically, the diameter of the first through hole 166 is 1.24mm. It will be appreciated that the aperture of the first through hole 166 is less than 1.55mm, so that excessive electrolyte is prevented from entering the first groove 16A and cannot contact the first tab 220. Meanwhile, the situation that the electrolyte in the first groove 16A cannot timely flow back to the pole core 210 through the first through hole 166 to influence the backflow efficiency of the electrolyte due to the fact that the first through hole 166 is blocked by rolling after the large-size sheet-shaped foreign matters (such as broken first pole lug 220, second pole lug 230, non-sticking first insulating film 331 and second insulating film 332) enter the first groove 16A can be avoided, so that the normal use of the energy storage device 1000 is influenced; the first through hole 166 has a hole diameter of more than 1.15mm, and provides a sufficient cross-sectional area for the electrolyte having a certain viscosity to pass smoothly.

In this embodiment, a first opening 167 is disposed at an end of the first sidewall 161 away from the first bottom wall 163 (i.e. an opening is disposed on a sidewall of the first groove), the first opening 167 penetrates the first sidewall 161, and the first opening 167 extends toward the side of the lower plastic body 11 and penetrates the first surface 111 and the second surface 112. The first opening 167 communicates the first recess 16A with the space on the second surface 112 side of the lower plastic body 11. It will be appreciated that the first opening 167 is formed by a recess at the junction of the first surface 111 and the end face of the first sidewall 161; i.e. through the junction of the first side wall 161 and the lower plastic body 11. The number of the first openings 167 may be plural, and the plural first openings 167 are arranged at intervals along the width direction (Y-axis direction) of the lower plastic 10. It will be appreciated that after the end cap assembly 100 is assembled in place, the first surface 111 side of the lower plastic body 11 is substantially adhered to the top cover 40, so that during transportation or use of the energy storage device 1000, electrolyte is likely to splash from the pole core 210 into the first groove 16A through the first through hole 166 due to factors such as vibration, overturning or accidental falling, and when the electrolyte entering the first groove 16A is about to flow back to the pole core 210 from the first through hole 166 under the action of gravity, a relatively closed space is formed in the first groove 16A due to the first bottom wall 163 being filled with the electrolyte; as the electrolyte continuously leaks to the pole piece 210 through the first groove 16A, a negative pressure area is gradually formed in the area above the electrolyte in the first groove 16A, and the existence of the negative pressure area counteracts part of the gravity action, so that the leakage of the electrolyte is slowed down; as the electrolyte continues to leak, the negative pressure gradually increases to balance with the gravitational force of the remaining electrolyte, and the remaining electrolyte is retained in the first groove 16A without leaking; the gas enters from the first through hole 166 and moves upwards to the negative pressure area to break the balance until the next vibration, turnover or accidental drop of the energy storage device 1000 occurs, and the rest electrolyte can continue to leak to the pole core 210; however, each time the energy storage device 1000 is vibrated, turned over, or accidentally dropped, the electrolyte may splash into the first groove 16A through the first through hole 166, and the electrolyte cannot completely leak back to the pole core 210. A first opening 167 at one end far away from the first bottom wall 163, when the negative pressure region is about to be formed, the gas in the space on the side of the second surface 112 of the lower plastic body 11 enters into the first groove 16A through the first opening 167, and damages the formation of the negative pressure region; the first opening 167 eliminates the air pressure difference between the space in the first groove 16A and the space on the side of the second surface 112 of the lower plastic body 11, so that the electrolyte in the first groove 16A can leak back to the pole core 210 rapidly under the action of gravity, and the situation that the electrolyte is retained in the first groove 16A and cannot contact with the first pole lug 220 of the pole core 210 is avoided, so that the efficiency of electrolyte backflow is accelerated, the electrolyte utilization rate is improved, and the service life of the energy storage device 1000 is further prolonged. Secondly, when the lower plastic 10 is injection molded, a movable die on the upper surface of the molding die is provided with a convex block which passes through the first side wall 161 in the area of the first groove 16A, a yielding gap is provided in the corresponding area of the fixed die on the lower surface, and the convex block and the gap are closely abutted to be matched with each other to seal a runner; after filling the inner cavity of the mold with molten plastic liquid, cooling and molding, separating the movable mold from bottom to top to smoothly demold, and then ejecting and demolding the molded lower plastic 10 from bottom to top by a pushing needle of the fixed mold; the forming die is simple to manufacture, and the demolding direction is single (only in the up-down direction), so that the integral forming process of the lower plastic 10 is simplified, the manufacturing cost of the die is reduced, and the production cost of parts of the lower plastic 10 is further reduced.

In the present embodiment, the first opening 167 has a rectangular shape. When the lower plastic 10 is injection molded, a movable die on the upper surface of the molding die is provided with a convex block which passes through the first side wall 161 in the area of the first groove 16A, a yielding gap is formed in the corresponding area of the fixed die on the lower surface, and the convex block and the gap are closely abutted to be matched with each other to seal a runner; after filling the inner cavity of the mold with molten plastic liquid, cooling and molding, separating the movable mold from bottom to top to smoothly demold, and then ejecting and demolding the molded lower plastic 10 from bottom to top by a pushing needle of the fixed mold; the forming die is simple to manufacture, and the demolding direction is single (only in the up-down direction), so that the integral forming process of the lower plastic 10 is simplified, the manufacturing cost of the die is reduced, and the production cost of parts of the lower plastic 10 is further reduced. In addition, the rectangular flat first opening 167 makes more use of the intake air from the top of the first groove 16A; at the same time, foreign matters such as broken first tab 220, second tab 230 or first insulating film 331, second insulating film 332 are prevented from entering to block first through hole 166, so that electrolyte cannot smoothly leak to lower electrode core 210.

The lower plastic 10 also includes reinforcing ribs. The reinforcing ribs are convexly arranged on the bottom wall of the groove, extend along the length direction of the lower plastic 10 and are connected with the side wall of the first groove and the side wall of the second groove, so that the grooves are separated to form a plurality of sub-grooves. In this embodiment, the stiffener includes a first stiffener 164. The first reinforcing rib 164 is located in the first groove 16A, and is protruding from the first bottom wall 163 along the thickness direction (Z-axis direction) of the lower plastic 10. The first reinforcing rib 164 extends along a length direction (X-axis direction) of the lower plastic 10 and connects the first side wall 161 and the second side wall 162. The end surface of the first reinforcing rib 164 away from the first bottom wall 163 is flush with the first surface 111 of the lower plastic body 11. In this embodiment, by disposing the first reinforcing rib 164 in the first groove 16A, the first reinforcing rib 164 is convexly disposed on the first bottom wall 163 and connects the first side wall 161 and the second side wall 162, so that the structural strength of the first groove 16A can be enhanced, and the second side wall 162 is supported so as not to be extruded and deformed by the pole core 210 to break when the energy storage device 1000 vibrates, turns over or falls accidentally; and when the lower plastic 10 is injection molded, a flow passage with a larger cross section area is provided, so that the fluidity of the plastic liquid and the molding uniformity of the lower plastic 10 are improved.

In the present embodiment, the plurality of first ribs 164 are sequentially spaced apart along the width direction (Y-axis direction) of the lower plastic 10, such that the first grooves 16A are separated to form a plurality of first sub-grooves 165. The first sub-groove 165 includes oppositely disposed first and second groove sidewalls 1651 and 1652, and a first groove bottom wall 1653 connecting the first and second groove sidewalls 1651 and 1652. Wherein the first slot sidewall 1651 is part of the first sidewall 161, the first slot sidewall 1651 may be understood as a first sub-slot sidewall, the second slot sidewall 1652 is part of the second sidewall 162, the second slot sidewall 1652 may be understood as a second sub-slot sidewall, the first slot bottom wall 1653 is part of the first bottom wall 163, and the first slot bottom wall 1653 may be understood as a first sub-slot bottom wall. It will be appreciated that the first and second slot side walls 1651, 1652 of the first sub-slot 165 are sloped to direct the accelerated flow of electrolyte to the first through-hole 166; the demolding resistance of the molding area of the first sub-groove 165 can be reduced, so that the movable mold, namely the mold provided with one surface inserted with the convex block of the first sub-groove 165 can be demolded upwards when the lower plastic 10 is subjected to injection molding.

Each first sub-groove 165 is provided with a first through hole 166, that is, each first groove bottom wall 1653 is correspondingly provided with a first through hole 166, and the first through hole 166 penetrates through the first groove bottom wall 1653. It is understood that the number of the first through holes 166 is plural, and the plurality of first through holes 166 are disposed in the plurality of first sub-grooves 165 in a one-to-one correspondence. In the use process of the energy storage device 1000, if the energy storage device 1000 shakes to cause electrolyte to splash into the first sub-groove 165, the electrolyte can flow back to the pole core 210 through the first through hole 166, so that the backflow efficiency of the electrolyte is improved, and the use efficiency of the electrolyte is improved.

Each first sub-groove 165 is provided with a first opening 167, that is, each first groove sidewall 1651 is correspondingly provided with a first opening 167, and the first opening 167 penetrates the first groove sidewall 1651. It is understood that the number of the first openings 167 is plural, and the first openings 167 are disposed in the first sub-grooves 165 in a one-to-one correspondence. Along the length direction of the lower plastic 10, the first openings 167 are symmetrical about a central line (see the O-O line of fig. 7), that is, the first openings 167 are symmetrical about the central line (see the O-O line of fig. 7) of the lower plastic 10; moreover, each first opening 167 is disposed at an end of the first groove sidewall 1651 away from the center line (see the O-O line in fig. 7), that is, each first opening 167 is disposed at an end of the first sidewall 161 away from the center line (see the O-O line in fig. 7). It will be appreciated that gas entering the first sub-recess 165 from the first opening 167 is not readily obscured by the first post 50 and/or the first flange 51 being assembled in place, affecting the gas intake; and, there is a distance of the long side of the first sub-groove 165 between each first opening 167, so as to avoid the too close distance between the first openings 167 and influence the air intake effect.

The number of the first sub-grooves 165 may be 2n, where n is a positive integer. In the width direction (Y-axis direction) of the lower plastic 10, the 2n first sub-grooves 165 are sequentially arranged and symmetrical with respect to a center line (see O-O line of fig. 7) of the lower plastic 10 in the length direction. Specifically, the number of first sub-grooves 165 is four.

In the present embodiment, the second protrusion 17 is protruding on the second surface 112, and the second groove 17A is formed on the first surface 111. It can be appreciated that the second groove 17A is recessed from the first surface 111 toward the second surface 112 and protrudes from the second surface 112, and the bottom wall of the second groove 17A supports the pole piece 210 below the second groove with a gap for accommodating the second adapter 320 and the second lug 230 connected to each other; in addition, the second groove 17A is internally provided with a cavity, so that the weight of the lower plastic 10 is reduced, and the overall weight of the energy storage device 1000 is further reduced; meanwhile, plastic materials are saved, the structural cost is reduced, and the production cost of the energy storage device 1000 is further reduced.

In the present embodiment, the second groove 17A includes a third end wall 170a and a fourth end wall 170b, a third side wall 171 and a fourth side wall 172, which are disposed opposite to each other, and a second bottom wall 173 connecting the third end wall 170a, the fourth end wall 170b, the third side wall 171 and the fourth side wall 172, the third end wall 170a and the fourth end wall 170b connect the third side wall 171 and the fourth side wall 172, one end of the third side wall 171 away from the second bottom wall 173 is connected to one end of the lower plastic body 11 in the length direction, that is, the fourth side wall 172 is located on one side of the third side wall 171 away from the second post through hole 14, that is, the second post through hole 14 is located on one side of the lower plastic body 11 close to the second groove 17A. Wherein the third end wall 170a may be understood as a first groove end wall, the fourth end wall 170b may be understood as a second groove end wall, the third side wall 171 may be understood as a first groove side wall, the fourth side wall 172 may be understood as a second groove side wall, and the second bottom wall 173 may be understood as a groove bottom wall.

In the present embodiment, the third end wall 170a, the fourth end wall 170b, the third side wall 171, and the fourth side wall 172 are disposed obliquely with respect to the center line in the thickness direction of the second groove 17A. The cross section of the second groove 17A is isosceles trapezoid along the middle line (see O-O line in fig. 7) of the lower plastic 10 in the length direction and the middle line (see O3-O3 line in fig. 7) of the second groove 17A in the width direction, and the second bottom wall 173 is a short side of the isosceles trapezoid. It will be appreciated that the peripheral walls of the second recess 17A (i.e., the third end wall 170a, the fourth end wall 170b, the third side wall 171, the fourth side wall 172) are sloped to guide the electrolyte to accelerate toward the second through hole 176; the demolding resistance of the molding area of the second groove 17A can be reduced, so that the movable mold, namely the mold provided with one surface inserted into the convex block of the second groove 17A can be demolded upwards when the lower plastic 10 is subjected to injection molding.

The second bottom wall 173 is provided with a second through hole 176 (i.e. the bottom wall of the groove is provided with a through hole), and the second through hole 176 penetrates through the second bottom wall 173 along the thickness direction of the lower plastic 10. The number of the second through holes 176 may be plural, and the plural second through holes 176 are arranged at intervals along the width direction (Y-axis direction) of the lower plastic 10. In the use process of the energy storage device 1000, if the energy storage device 1000 shakes to cause the electrolyte to splash into the second groove 17A, the electrolyte can flow back to the pole core 210 through the second through hole 176, so that the backflow efficiency of the electrolyte is improved, and the use efficiency of the electrolyte is improved.

In this embodiment, the diameter of the second through hole 176 is 1.15 mm-1.55 mm; specifically, the diameter of the second through hole 176 is 1.24mm. It will be appreciated that the second through hole 176 has a hole diameter of less than 1.55mm, which can prevent excessive electrolyte from entering the second recess 17A and failing to contact the second tab 230. Meanwhile, the situation that the electrolyte in the second groove 17A cannot timely flow back to the pole core 210 through the second through hole 176 to influence the backflow efficiency of the electrolyte due to the fact that the second through hole 176 is blocked by rolling after the large-size sheet-shaped foreign matters (such as broken first pole lug 220, second pole lug 230, non-sticking first insulating film 331, second insulating film 332 and the like) enter the second groove 17A can be avoided, so that the normal use of the energy storage device 1000 is influenced; the second through hole 176 has a hole diameter of more than 1.15mm, and provides a sufficient cross-sectional area for the electrolyte having a certain viscosity to pass smoothly.

In the present embodiment, a second opening 177 is disposed at an end of the third sidewall 171 away from the second bottom wall 173 (i.e. an opening is disposed on the sidewall of the first groove), the second opening 177 penetrates the third sidewall 171, and the second opening 177 extends toward the side of the lower plastic body 11 and penetrates the first surface 111 and the second surface 112. The second opening 177 communicates the second recess 17A with the space on the second surface 112 side of the lower plastic body 11. It will be appreciated that the second opening 177 is recessed from the junction of the first surface 111 and the end face of the third sidewall 171; i.e. through the junction of the third side wall 171 and the lower plastic body 11. The number of the second openings 177 may be plural, and the plural second openings 177 are arranged at intervals along the width direction (Y-axis direction) of the lower plastic 10. It will be appreciated that after the end cap assembly 100 is assembled in place, the first surface 111 side of the lower plastic body 11 is substantially adhered to the top cover 40, so that during transportation or use of the energy storage device 1000, electrolyte is likely to splash from the pole core 210 into the second groove 17A through the second through hole 176, and when electrolyte entering the second groove 17A will flow back to the pole core 210 from the second through hole 176 under the action of gravity, a relatively closed space is formed in the second groove 17A due to the second bottom wall 173 being filled with electrolyte; as the electrolyte continuously leaks to the pole core 210 through the second groove 17A, a negative pressure area is gradually formed in the area above the electrolyte in the second groove 17A, and the existence of the negative pressure area counteracts part of the gravity action, so that the leakage of the electrolyte is slowed down; as the electrolyte continues to leak, the negative pressure gradually increases to balance with the gravity action of the rest electrolyte, and the rest electrolyte is not leaked any more and is retained in the second groove 17A; the next time the energy storage device 1000 is vibrated, turned over or accidentally dropped, the gas enters from the second through hole 176 and moves upwards to the negative pressure area to break the balance, and the rest electrolyte can continue to leak to the pole core 210; however, each time the energy storage device 1000 is vibrated, turned over, or accidentally dropped, the electrolyte may splash into the second groove 17A through the second through hole 176, and the electrolyte cannot completely leak back to the pole core 210. A second opening 177 at one end far away from the second bottom wall 173, when the negative pressure region is to be formed, the gas in the space on the side of the second surface 112 of the lower plastic body 11 enters the second groove 17A through the second opening 177, and damages the formation of the negative pressure region; the second opening 177 eliminates the air pressure difference between the space inside the second groove 17A and the space on the side of the second surface 112 of the lower plastic body 11, so that the electrolyte inside the second groove 17A can leak back to the pole core 210 rapidly under the action of gravity, and the situation that the electrolyte is retained inside the second groove 17A and cannot contact with the second lug 230 of the pole core 210 is avoided, so that the efficiency of electrolyte backflow is accelerated, the electrolyte utilization rate is improved, and the service life of the energy storage device 1000 is further prolonged. Secondly, when the lower plastic 10 is injection molded, a movable die on the upper surface of the molding die is provided with a convex block which passes through the third side wall 171 in the area of the second groove 17A, a yielding gap is provided in the corresponding area of the fixed die on the lower surface, and the convex block and the gap are closely abutted to be matched with each other to seal a runner; after filling the inner cavity of the mold with molten plastic liquid, cooling and molding, separating the movable mold from bottom to top to smoothly demold, and then ejecting and demolding the molded lower plastic 10 from bottom to top by a pushing needle of the fixed mold; the forming die is simple to manufacture, and the demolding direction is single (only in the up-down direction), so that the integral forming process of the lower plastic 10 is simplified, the manufacturing cost of the die is reduced, and the production cost of parts of the lower plastic 10 is further reduced.

In the present embodiment, the second opening 177 is rectangular. When the lower plastic 10 is injection molded, a movable die on the upper surface of the molding die is provided with a convex block which passes through the third side wall 171 in the area of the second groove 17A, a yielding gap is formed in the corresponding area of the fixed die on the lower surface, and the convex block and the gap are closely abutted to be matched with each other to seal a runner; after filling the inner cavity of the mold with molten plastic liquid, cooling and molding, separating the movable mold from bottom to top to smoothly demold, and then ejecting and demolding the molded lower plastic 10 from bottom to top by a pushing needle of the fixed mold; the forming die is simple to manufacture, and the demolding direction is single (only in the up-down direction), so that the integral forming process of the lower plastic 10 is simplified, the manufacturing cost of the die is reduced, and the production cost of parts of the lower plastic 10 is further reduced. In addition, the rectangular flat second opening 177 further utilizes the intake air from the top of the second groove 17A; at the same time, foreign matters such as the broken first tab 220, second tab 230, first insulating film 331, second insulating film 332 and the like are prevented from entering and blocking the second through hole 176, so that the electrolyte cannot smoothly leak to the lower electrode core 210.

In this embodiment, the stiffener further includes a second stiffener 174. The second reinforcing rib 174 is located in the second groove 17A, and is protruding on the second bottom wall 173 along the thickness direction (Z-axis direction) of the lower plastic 10. The second reinforcing rib 174 extends along the length direction (X-axis direction) of the lower plastic 10 and connects the third side wall 171 and the fourth side wall 172. The end surface of the second reinforcing rib 174 away from the second bottom wall 173 is flush with the first surface 111 of the lower plastic body 11. In this embodiment, by disposing the second reinforcing rib 174 in the second groove 17A, the second reinforcing rib 174 is convexly disposed on the second bottom wall 173 and connects the third side wall 171 and the fourth side wall 172, so that the structural strength of the second groove 17A can be enhanced, and the fourth side wall 172 is supported so as not to be extruded and deformed by the pole core 210 to break when the energy storage device 1000 vibrates, turns over or falls accidentally; and when the lower plastic 10 is injection molded, a flow passage with a larger cross section area is provided, so that the fluidity of the plastic liquid and the molding uniformity of the lower plastic 10 are improved.

In the present embodiment, the plurality of second reinforcing ribs 174 are sequentially spaced apart along the width direction (Y-axis direction) of the lower plastic 10, such that the second grooves 17A are divided to form a plurality of second sub-grooves 175. The second sub-groove 175 includes oppositely disposed third and fourth groove sidewalls 1751 and 1752, and a second groove bottom wall 1753 connecting the third and fourth groove sidewalls 1751 and 1752. Wherein third slot sidewall 1751 is part of third sidewall 171, third slot sidewall 1751 can be understood as a first sub-slot sidewall, fourth slot sidewall 1752 is part of fourth sidewall 172, fourth slot sidewall 1752 can be understood as a second sub-slot sidewall, second slot bottom wall 1753 is part of second bottom wall 173, and second slot bottom wall 1753 can be understood as a second sub-slot bottom wall. It will be appreciated that the third slot sidewall 1751 and the fourth slot sidewall 1752 of the second sub-slot 175 are sloped to direct the accelerated flow of electrolyte to the second via 176; the demolding resistance of the molding area of the second sub-groove 175 can be reduced, so that the movable mold, namely the mold provided with one surface inserted with the convex block of the second sub-groove 175 can be demolded upwards when the lower plastic 10 is subjected to injection molding.

Each second sub-groove 175 is provided with a second through hole 176, i.e. each second groove bottom wall 1753 is correspondingly provided with a second through hole 176, and the second through holes 176 penetrate through the second groove bottom wall 1753. It is understood that the number of the second through holes 176 is plural, and the plurality of second through holes 176 are disposed in the plurality of second sub-grooves 175 in a one-to-one correspondence. In the use process of the energy storage device 1000, if the energy storage device 1000 shakes to cause the electrolyte to splash into the second sub-groove 175, the electrolyte can flow back to the pole core 210 through the second through hole 176, which is beneficial to improving the backflow efficiency of the electrolyte, thereby improving the use efficiency of the electrolyte.

Each second sub-groove 175 is provided with a second opening 177, i.e. each third groove sidewall 1751 is correspondingly provided with a second opening 177, and the second openings 177 penetrate the third groove sidewalls 1751. It is understood that the number of the second openings 177 is plural, and the plurality of second openings 177 are disposed in a one-to-one correspondence with the plurality of second sub-grooves 175. Along the length direction of the lower plastic 10, the second openings 177 are symmetrical about a center line (see the O-O line of fig. 7), i.e., the second openings 177 are symmetrical about the center line (see the O-O line of fig. 7) of the lower plastic 10; moreover, each of the second openings 177 is disposed at an end of the third slot sidewall 1751 away from the centerline (see the O-O line in fig. 7), that is, each of the second openings 177 is disposed at an end of the third sidewall 171 away from the centerline (see the O-O line in fig. 7). It will be appreciated that gas entering the second sub-recess 175 from the second opening 177 is not readily obstructed by the second post 60 and/or the second flange 61 being assembled in place, affecting the gas intake; and, there is a distance of the long limit of second sub-recess 175 between each second opening 177, avoid the distance between the second openings 177 too close, influence the air inlet effect each other.

The number of second sub-grooves 175 may be 2n, where n is a positive integer. In the width direction (Y-axis direction) of the lower plastic 10, the 2n second sub-grooves 175 are sequentially arranged and symmetrical with respect to the center line (see the O-O line of fig. 7) of the length direction of the lower plastic 10. Specifically, the number of second sub-grooves 175 is four.

Referring to fig. 7 and 8, in the present embodiment, the explosion-proof fence 18 is disposed in the middle of the lower plastic body 11 and opposite to the explosion-proof valve 44 (i.e. opposite to the through slot 47). The lower plastic body 11 and the explosion-proof fence 18 may be an integrally formed structural member. The explosion-proof fence 18 protrudes from the second surface 112 of the lower plastic body 11 to protect the explosion-proof valve 44 and ensure the reliability of opening the explosion-proof valve 44. Because the energy storage device 1000 is easy to break and generate fragments in the transportation and use processes of the first tab 220, the second tab 230, the first insulating film 331, the second insulating film 332 and the like, the fragments of the first tab 220, the second tab 230, the first insulating film 331, the second insulating film 332 and the like can be prevented from floating below the explosion-proof valve 44 through the explosion-proof fence 18, shielding of an air passage is avoided, explosion-proof failure is further caused, and the broken first tab 220 and second tab 230 can be prevented from drifting to the explosion-proof valve 44, so that short circuit caused by electric connection of the first tab 220, the second tab 230 and the top cover 40 is avoided.

In the present embodiment, the explosion-proof fence 18 protrudes from the second surface 112 of the lower plastic body 11, and a groove portion 18A is formed on the first surface 111 of the lower plastic body 11.

In this embodiment, the explosion-proof fence 18 is located in the middle of the lower plastic body 11 along the length direction (X-axis direction) of the lower plastic 10. The explosion-proof barrier 18 includes two opposing barrier side walls (not shown) and a barrier bottom wall (not shown) connecting the two barrier side walls. The bottom wall of the fence is provided with a plurality of diversion holes 180, and the diversion holes 180 are arranged at intervals. The diversion holes 180 penetrate the bottom wall of the fence along the thickness direction (Z-axis direction) of the lower plastic 10.

The explosion barrier 18 is generally in the shape of a candy comprising a first portion 181, a second portion 182, and a third portion 183; the length of the second portion 182 and the third portion 183 is smaller than the length of the first portion 181 in the width direction (Y-axis direction) of the lower plastic 10. The second portion 182 and the third portion 183 connect the first portion 181 and are located on opposite sides of the width direction of the first portion 181; along the width direction (Y-axis direction) of the lower plastic 10, the second portion 182 and the third portion 183 are located at the middle of the lower plastic body 11, and the lengths of the second portion 182 and the third portion 183 are greater than the length of the explosion-proof valve 44; the first portion 181 is a rectangular parallelepiped extending along the width direction of the lower plastic 10.

In this embodiment, the first portion 181 includes two opposing end walls (not labeled), a first fence side wall 1811, a second fence side wall 1812, and a first fence bottom wall 1813. The first barrier sidewall 1811 and the second barrier sidewall 1812 are disposed opposite to each other, and the first barrier bottom wall 1813 connects the two end walls (not shown), the first barrier sidewall 1811, and the second barrier sidewall 1812. Wherein the first barrier sidewall 1811 is a portion of one barrier sidewall of the explosion-proof barrier 18, the second barrier sidewall 1812 is a portion of the other barrier sidewall of the explosion-proof barrier 18, and the first barrier bottom wall 1813 is a portion of the barrier bottom wall of the explosion-proof barrier 18.

The first fence bottom wall 1813 includes a first outer surface 1813a and a first inner surface 1813b, where the first outer surface 1813a and the first inner surface 1813b are disposed opposite to each other along the thickness direction of the lower plastic 10, the first outer surface 1813a protrudes from the second surface 112, and the first inner surface 1813b is located in the groove 18A, that is, a groove wall surface of the groove 18A. The first outer surface 1813a is provided with a plurality of diversion holes 180, the plurality of diversion holes 180 penetrate through the first fence bottom wall 1813 of the first portion 181, that is, the plurality of diversion holes 180 penetrate through the first outer surface 1813a and the first inner surface 1813b, that is, along the thickness direction of the lower plastic 10, the plurality of diversion holes 180 penetrate through the first portion 181.

Referring to fig. 7 and 9, in the present embodiment, a height difference H1 exists between the first outer surface 1813a and the second surface 112 along the thickness direction of the lower plastic 10.

Referring to fig. 7 and 8, in the present embodiment, the second portion 182 includes a third barrier side wall 1821 and a second barrier bottom wall 1822. Third barrier sidewall 1821 and second barrier bottom wall 1822 are connected to first barrier sidewall 1811. The third barrier sidewall 1821 is arcuate. Wherein the third barrier sidewall 1821 is a portion of one barrier sidewall of the explosion barrier 18 and the second barrier bottom wall 1822 is a portion of the barrier bottom wall of the explosion barrier 18.

The second barrier bottom wall 1822 includes a second outer surface 1822a and a second inner surface 1822b, where the second outer surface 1822a and the second inner surface 1822b are disposed opposite to each other along the thickness direction of the lower plastic 10, the second outer surface 1822a protrudes from the second surface 112, and the second inner surface 1822b is located in the groove 18A, i.e. is a groove wall surface of the groove 18A. The second outer surface 1822a is provided with a plurality of diversion holes 180, and the plurality of diversion holes 180 penetrate through the second barrier bottom wall 1822 of the second portion 182, that is, the plurality of diversion holes 180 penetrate through the second outer surface 1822a and the second inner surface 1822b, that is, along the thickness direction of the lower plastic 10, and the plurality of diversion holes 180 penetrate through the second portion 182.

Referring to fig. 7 and 9, in the present embodiment, a height difference H2 exists between the second outer surface 1822a and the second surface 112 along the thickness direction of the lower plastic 10.

In the present embodiment, the height difference H1 between the first outer surface 1813a and the second surface 112 is greater than the height difference H2 between the second outer surface 1822a and the second surface 112. I.e., along the direction of the first surface 111 toward the second surface 112, the first portion 181 protrudes from the second portion 182, i.e., the first barrier bottom wall 1813 protrudes from the second barrier bottom wall 1822 as compared to the second surface 112. A stepped structure is formed between the first portion 181 and the second portion 182. It can be understood that, along the direction from the first surface 111 to the second surface 112, the first portion 181 protrudes from the second portion 182, and the first portion 181 can abut against the electrode core 210, so as to avoid the first tab 220 and the second tab 230 from being bent and broken greatly, and improve the structural reliability; the distance between the top cover 40 and the first and second tabs 220, 230 is increased, and the first and second tabs 220, 230 and the top cover 40 are prevented from being shorted. In addition, if the pole core 210 is pressed up due to impact or drop and shields the diversion hole 180 of the first fence bottom wall 1813, the gas generated by the pole core 210 can flow from the diversion hole 180 of the second fence bottom wall 1822 to the position of the explosion-proof valve 44, so as to improve the reliability of opening the explosion-proof valve 44. After the energy storage device 1000 is recycled for multiple times, the gas generated at the two ends of the lower plastic 10 in the length direction of the pole core 210 can enter from the first through hole 166, flow to the space on the side of the second surface 112 of the lower plastic body 11 through the first opening 167, and flow guiding holes 180 on the second outer surface 1822a are collected below the explosion-proof valve 44, so that the explosion-proof valve 44 cannot burst and release at the accurate threshold due to local air trapping, and the safety performance of the energy storage device 1000 is improved.

Referring to fig. 7 and 8, third portion 183 includes a fourth barrier side wall 1831 and a third barrier bottom wall 1832. Fourth barrier sidewall 1831 connects first barrier sidewall 1811. Fourth barrier sidewall 1831 connects first barrier sidewall 1811. Fourth barrier sidewall 1831 is arcuate. Wherein the fourth barrier sidewall 1831 is a portion of another barrier sidewall of the explosion-proof barrier 18 and the third barrier bottom wall 1832 is a portion of a barrier bottom wall of the explosion-proof barrier 18.

The third fence bottom wall 1832 includes a third outer surface 1832a and a third inner surface 1832b, the third outer surface 1832a and the third inner surface 1832b are disposed opposite to each other along the thickness direction of the lower plastic 10, the third outer surface 1832a protrudes from the second surface 112, and the third inner surface 1832b is located in the groove 18A, that is, a groove wall of the groove 18A. Third outer surface 1832a is provided with a plurality of deflector apertures 180, the plurality of deflector apertures 180 extending through third barrier bottom wall 1832 of third portion 183, i.e., the plurality of deflector apertures 180 extending through third outer surface 1832a and third inner surface 1832b.

Referring to fig. 7 and 9, in the present embodiment, a height difference H3 exists between the third outer surface 1832a and the second surface 112 along the thickness direction of the lower plastic 10.

In the present embodiment, the height difference H1 between the first outer surface 1813a and the second surface 112 is greater than the height difference H3 between the third outer surface 1832a and the second surface 112, i.e. along the direction of the first surface 111 toward the second surface 112, the first portion 181 protrudes from the third portion 183, i.e. along the direction of the first surface 111 toward the second surface 112, compared to the second surface 112, the first portion 181 protrudes from the third portion 183, i.e. the first barrier bottom wall 1813 protrudes from the third barrier bottom wall 1832. A stepped structure is formed between the first portion 181 and the third portion 183. It can be appreciated that, along the direction from the first surface 111 to the second surface 112, the first portion 181 protrudes from the third portion 183, and the first portion 181 can abut against the electrode core 210, so that not only the first tab 220 and the second tab 230 can be prevented from being bent and broken substantially, the reliability of the structure can be improved, but also the distance between the top cover 40 and the first tab 220 and the distance between the second tab 230 can be increased, and the first tab 220, the second tab 230 and the top cover 40 can be prevented from being shorted. In addition, if the pole core 210 is pressed up due to impact or drop and shields the diversion hole 180 of the first fence bottom wall 1813, the gas generated by the pole core 210 can flow from the diversion hole 180 of the third fence bottom wall 1832 to the position of the explosion-proof valve 44, so as to improve the reliability of opening the explosion-proof valve 44. After the energy storage device 1000 is recycled for multiple times, the gas generated at the two ends of the lower plastic 10 in the length direction of the pole core 210 can enter from the second through hole 176, flow to the space on the side of the second surface 112 of the lower plastic body 11 through the second opening 177, and flow from the flow guiding hole 180 of the third outer surface 1832a to the lower side of the explosion-proof valve 44, so as to avoid the explosion-proof valve 44 from being unable to burst and release at the accurate threshold due to local air trapping, and further improve the safety performance of the energy storage device 1000.

Referring to fig. 7 and 8, in the present embodiment, the first fence sidewall 1811 has a first notch 1814, and along the length direction (X-axis direction) of the lower plastic 10, the first notch 1814 penetrates a portion of the first fence sidewall 1811 and communicates with the first portion 181 and the second portion 182. It will be appreciated that the first notch 1814 is recessed from a portion of the first surface 111 toward the second surface 112 to communicate with the first barrier sidewall 1811 and form a first inner wall surface 1815 on the first barrier sidewall 1811. The first inner wall surface 1815 is located in the groove portion 18A and faces away from the second surface 112. The second barrier bottom wall 1822 is partially connected to the first inner wall surface 1815. The second inner surface 1822b protrudes from the first inner wall surface 1815 along the second surface 112 toward the first surface 111; the first inner wall surface 1815 protrudes from the first inner surface 1813b.

In the present embodiment, the second fence side wall 1812 has a second notch 1816, and along the length direction (X-axis direction) of the lower plastic 10, the second notch 1816 penetrates part of the second fence side wall 1812 and communicates with the first portion 181 and the third portion 183. It will be appreciated that the second notch 1816 is recessed from a portion of the first surface 111 toward the second surface 112 to communicate with the second barrier sidewall 1812 and form a second inner wall surface 1817 on the second barrier sidewall 1812. The second inner wall surface 1817 is located in the groove portion 18A and faces away from the second surface 112. The third barrier bottom wall 1832 is partially connected to the second inner wall surface 1817. The third inner surface 1832b protrudes from the second inner wall 1817 along the second surface 112 toward the first surface 111; the second inner wall surface 1817 protrudes from the first inner surface 1813b.

Referring to fig. 4, 5 and 9, the lower plastic 10 is laminated and connected with the top cover 40, the length of the lower plastic 10 is the same as the length of the top cover 40, and the width of the lower plastic 10 is equal to the width of the top cover 40, wherein a certain tolerance range is allowed. Specifically, the first surface 111 of the lower plastic body 11 is opposite to and adhered to the back surface 412 of the top cover body 41. The first catching protrusion 131 is inserted into the first mounting groove 413, and the second catching protrusion 151 is inserted into the second mounting groove 414; the first clamping protrusion 131 and the first mounting groove 413 can be mutually clamped to achieve mutual positioning, and the second clamping protrusion 151 and the second mounting groove 414 can be mutually clamped to achieve mutual positioning. Along the thickness direction (Z-axis direction) of the top cover 40, the first post through hole 12 of the lower plastic 10 is disposed opposite to and communicates with the first mounting hole 42 of the top cover 40, and the second post through hole 14 is disposed opposite to and communicates with the second mounting hole 43 of the top cover 40. The explosion proof barrier 18 of the lower plastic 10 is disposed opposite the explosion proof valve 44 of the top cover 40.

The first pole 50 passes through the first pole through hole 12 and the first mounting hole 42, and the first flange 51 is accommodated in the first recess 13; the first adaptor 310 is laminated on the second surface 112 of the lower plastic body 11, and the first body 311 of the first adaptor 310 is connected to the first flange 51 by welding or the like. Along the thickness direction (Z-axis direction) of the end cap assembly 100, the first flange 51 protrudes from the second surface 112 of the lower plastic body 11, such that a gap exists between the first adapter 310 and the second surface 112 of the lower plastic body 11. The first insulating film 331 is located in a gap between the first adaptor 310 and the second surface 112 of the lower plastic body 11. The first insulating film 331 can prevent the surfaces of the first adapter 312 and the second adapter 313 from rubbing against the lower plastic body 11, and prevent metal chips generated by rubbing against the lower plastic body 11 and indentations formed by welding the first adapter 310 and the first flange 51 from falling into the core 210, thereby causing internal short circuit of the battery.

The first upper surface 3314 of the first insulating film 331 and the second surface 112 of the lower plastic body 11 have a gap S therebetween. It will be appreciated that the gap between the first upper surface 3314 of the first insulating film 331 and the second surface 112 of the lower plastic body 11 forms an air passage through which the air within the first recess 16A may flow from the first opening 167, into the explosion proof barrier 18 from the flow directing aperture 180 of the second portion 182 of the explosion proof barrier 18, and collect below the explosion proof valve 44. Thus, the gas generated by the electrode core 210 is not easy to gather in the first groove 16A, that is, the gas trapped in the first groove 16A is avoided, the gas generated by the electrode core 210 can flow to the explosion-proof valve 44 and gather below the explosion-proof valve 44, so that the reliability of opening the explosion-proof valve 44 can be improved, the opening of the explosion-proof valve 44 is ensured, and the safety performance of the battery is better.

The second post 60 passes through the second post through hole 14 and the second mounting hole 43, and the second flange 61 is accommodated in the second recess 15; the second adaptor 320 is laminated on the second surface 112 of the lower plastic body 11, and the second body 321 of the second adaptor 320 is connected to the second flange 61 by welding or the like. Along the thickness direction (Z-axis direction) of the end cap assembly 100, the second flange 61 protrudes from the second surface 112 of the lower plastic body 11, such that a gap exists between the second adapter 320 and the second surface 112 of the lower plastic body 11. The second insulating film 332 is located in the gap between the second adaptor 320 and the second surface 112 of the lower plastic body 11. The second insulating film 332 can prevent the surfaces of the third adapter 322 and the fourth adapter 323 from rubbing against the lower plastic body 11, and prevent metal chips generated by the rubbing against the lower plastic body 11 and the indentations formed by welding the second adapter 320 and the second flange 61 from falling into the core 210, thereby causing internal short circuit of the battery.

The second upper surface 3324 of the second insulating film 332 has a gap with the second surface 112 of the lower plastic body 11. It will be appreciated that the gap between the second upper surface 3324 of the second insulating film 332 and the second surface 112 of the lower plastic body 11 forms an air passage through which the air within the second recess 17A may flow out of the second opening 177, enter the explosion proof barrier 18 from the deflector aperture 180 of the third portion 183 of the explosion proof barrier 18, and collect below the explosion proof valve 44. Thus, the gas generated by the electrode core 210 is not easy to gather in the second groove 17A, that is, the gas trapped in the second groove 17A is avoided, the gas generated by the electrode core 210 can flow to the explosion-proof valve 44 and gather below the explosion-proof valve 44, so that the reliability of opening the explosion-proof valve 44 can be improved, the opening of the explosion-proof valve 44 is ensured, and the safety performance of the battery is better.

The foregoing has outlined rather broadly the more detailed description of embodiments of the present application, wherein specific examples are provided herein to illustrate the principles and embodiments of the present application, the above examples being provided solely to assist in the understanding of the methods of the present application and the core ideas thereof; meanwhile, as those skilled in the art will have modifications in the specific embodiments and application scope in accordance with the ideas of the present application, the present description should not be construed as limiting the present application in view of the above.

Claims

1. An end cap assembly for an energy storage device, comprising: a top cover and a lower plastic;

the top cover comprises a top cover body, and the top cover body comprises a front surface and a back surface which is arranged back to the front surface along the thickness direction of the top cover body;

the lower plastic comprises a lower plastic body, wherein the lower plastic body is provided with a first surface and a second surface, the first surface and the second surface are arranged back to back along the thickness direction of the lower plastic, and the first surface is opposite to and attached to the back;

the lower plastic further comprises a groove, the groove is recessed from the first surface to the second surface and protrudes out of the second surface, the groove comprises a first groove side wall and a second groove side wall which are oppositely arranged, and a groove bottom wall which is connected with the first groove side wall and the second groove side wall, the groove further comprises a first groove end wall and a second groove end wall which are oppositely arranged, and the first groove end wall and the second groove end wall are connected with the first groove side wall, the second groove side wall and the groove bottom wall; the bottom wall of the groove is provided with a through hole, the through hole penetrates through the bottom wall of the groove along the thickness direction of the lower plastic, the diameter of the through hole is 1.15 mm-1.55 mm, and one end of the side wall of the first groove, which is far away from the bottom wall of the groove, is connected with one end of the lower plastic body in the length direction;

The one end that first recess lateral wall kept away from the recess diapire is equipped with the opening, the opening runs through first recess lateral wall, the opening orientation one side of plastic body down extends, and runs through first surface with the second surface, the opening intercommunication the recess with the second surface one side space of plastic body down.

2. The end cap assembly of claim 1, wherein the lower plastic body further comprises a post through hole spaced from the recess and located on a side of the lower plastic body adjacent to the recess;

the lower plastic comprises a reinforcing rib, the reinforcing rib is located in the groove and is arranged on the bottom wall of the groove in a protruding mode, the reinforcing rib extends along the length direction of the lower plastic and is connected with the side wall of the first groove and the side wall of the second groove, the grooves are divided to form a plurality of sub-grooves, and each sub-groove is correspondingly provided with a through hole and an opening.

3. The end cap assembly of claim 2, wherein a plurality of the openings are centerline symmetric along a length of the lower plastic, and each of the openings is disposed at an end of the first groove sidewall distal from the centerline.

4. The end cap assembly of claim 2 or 3 wherein said first groove end wall, said second groove end wall, said first groove side wall and said second groove side wall are each disposed obliquely with respect to a centerline of said groove in a thickness direction thereof;

the cross section of the groove is isosceles trapezoid along the middle line of the lower plastic in the length direction and the middle line of the groove in the width direction, and the bottom wall of the groove is the short side of the isosceles trapezoid.

5. An end cap assembly according to claim 2 or claim 3 wherein the end face of the rib remote from the bottom wall of the recess is flush with the first surface.

6. The end cap assembly of any one of claims 1 to 3 wherein the opening is rectangular.

7. The end cap assembly of any one of claims 1 to 3, wherein the lower plastic further comprises an explosion-proof barrier located in a middle portion of the lower plastic body and protruding from the second surface;

the explosion-proof fence comprises a first part, a second part and a third part, wherein the second part and the third part are connected with the first part and are positioned on two opposite sides of the first part in the width direction;

The first part comprises a first outer surface, the first outer surface protrudes out of the second surface, and a height difference H1 exists between the first outer surface and the second surface along the thickness direction of the lower plastic;

the second part comprises a second outer surface, the second outer surface protrudes out of the second surface, a height difference H2 exists between the second outer surface and the second surface along the thickness direction of the lower plastic, and H1 is more than H2;

the third part comprises a third outer surface, the third outer surface protrudes out of the second surface, a height difference H3 exists between the third outer surface and the second surface along the thickness direction of the lower plastic, and H1 is more than H3;

the first outer surface, the second outer surface and the third outer surface are provided with a plurality of diversion holes; and a plurality of flow guide holes penetrate through the first part, the second part and the third part along the thickness direction of the lower plastic.

8. The end cap assembly of claim 7, wherein the length of the second portion and the third portion is less than the length of the first portion along the width of the lower plastic;

the lower plastic further comprises a through groove, the through groove is opposite to the explosion-proof fence, the through groove is used for installing an explosion-proof valve, and the length of the second part and the length of the third part are greater than the length of the explosion-proof valve along the width direction of the lower plastic.

9. An energy storage device comprising an adapter, a coiled electrode assembly and an end cap assembly according to any one of claims 1 to 8, the end cap assembly further comprising a post, a flange provided at one end of the post;

the lower plastic comprises a concave part concavely arranged on the second surface, the pole penetrates through the lower plastic, the flange is accommodated in the concave part, and the flange protrudes out of the second surface;

the adapter is connected with the flange and the winding electrode assembly, and the flange and the winding electrode assembly are positioned on two opposite sides of the adapter.

10. The energy storage device of claim 9, comprising an insulating film comprising an upper surface and a lower surface disposed opposite, the lower surface being connected to a side of the adapter facing away from the coiled electrode assembly, the upper surface and the second surface having a gap therebetween.

11. A powered device comprising an energy storage device according to claim 9 or 10 for storing electrical energy.