End cap assembly, energy storage apparatus, energy storage module and electric device

Abstract

Disclosed in the present application are an end cap assembly, an energy storage apparatus, an energy storage module and an electric device. The end cap assembly comprises an end cap, lower plastic, a first sealing ring and a first terminal post. The end cap comprises a first surface and a second surface, and the end cap is provided with a first through hole. The lower plastic is provided with a first terminal-post through hole. The first terminal post comprises a first flange, a first terminal-post body and a first insulating layer, wherein the first flange comprises a first end face, and the first insulating layer completely covers the first end face. The lower plastic is stacked on the second surface; the first flange presses against the side of the lower plastic facing away from the end cap; the first terminal-post body sequentially runs through the first terminal-post through hole and the first through hole; the first sealing ring is sleeved on the first terminal-post body and sequentially runs through the first terminal-post through hole and the first through hole; and the first sealing ring abuts between the first terminal-post body and the hole wall of the through hole, and the first sealing ring is spaced apart from the hole wall of the first terminal-post through hole.

Description

End cover assembly, energy storage device, energy storage module and electric equipment

[0001] The present application claims priority to the Chinese patent application No. 2024106743711, filed on May 28, 2024, entitled "End cover assembly, energy storage device, energy storage module and electric equipment", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of energy storage, in particular to an end cover assembly, an energy storage device, an energy storage module and an electric equipment. BACKGROUND

[0003] A secondary battery, also known as a rechargeable battery or a storage battery, refers to a battery that can be activated by charging after discharging to continue to be used. The recyclable nature of the secondary battery makes it gradually become the main power source of electric equipment. As the demand for secondary batteries gradually increases, people have higher requirements for their energy density, reliability and cost. The end cover assembly of the secondary battery usually includes an end cover and a pole. The pole is inserted into the end cover, and the end cover and the pole are easily misdirected, causing the energy storage device to short circuit and affecting the normal operation of the energy storage device. SUMMARY

[0004] The present application provides an end cover assembly, an energy storage device, an energy storage module and an electric equipment, which can improve the working reliability of the energy storage device.

[0005] The first aspect of the present application provides an end cover assembly applied to an energy storage device, comprising an end cover, a lower plastic, a first sealing ring and a first pole, the end cover comprising a first surface and a second surface oppositely arranged with the first surface, the end cover being provided with a first through hole, the first through hole penetrating the first surface and the second surface;

[0006] The lower plastic is provided with a first pole through hole, the first pole through hole penetrating two surfaces of the lower plastic oppositely arranged along the thickness direction;

[0007] The first pole comprises a first flange, a first pole body and a first insulating layer, the first flange comprising a first end face, the first pole body being protruded from the first end face, and the first insulating layer completely covering the first end face;

[0008] The first flange of the first pole is press-fitted on one side of the lower plastic away from the end cover, the first pole body is sequentially arranged in the first pole through hole and the first through hole, the first sealing ring is sleeved on the first pole body, and the first sealing ring is sequentially arranged in the first pole through hole and the first through hole. The first sealing ring is arranged between the first pole body and the hole wall of the first through hole.

[0009] The second aspect of the present application provides an energy storage device, comprising a shell, an electrode assembly and an end cover assembly as described above, the shell comprises a shell body, the shell body is provided with an opening and a receiving cavity, along the height direction of the energy storage device, the opening is located on one side of the receiving cavity and communicates with the receiving cavity;

[0010] The electrode assembly is located in the receiving cavity, and the end cover assembly covers the opening;

[0011] The energy storage device further comprises an electrolyte, the electrolyte is contained in the receiving cavity, and the electrode assembly is soaked in the electrolyte;

[0012] The shell comprises a fifth insulating layer, the fifth insulating layer covers the cavity wall of the receiving cavity, and the fifth insulating layer can isolate the electrolyte from the cavity wall of the receiving cavity.

[0013] The third aspect of the present application provides an energy storage module, comprising a cluster frame and a plurality of energy storage devices as described above, each of the energy storage devices is wrapped with an insulating film, a plurality of the energy storage devices are placed in the cluster frame, and a plurality of the energy storage devices are sequentially arranged, and every two adjacent energy storage devices are connected in series.

[0014] The fourth aspect of the present application provides an electric equipment, comprising an energy storage module as described above, and the energy storage module is used for storing electric energy.

[0015] The beneficial effects of the present application are that there is a gap between the first sealing ring and the hole wall of the first pole through hole. By arranging the first insulating layer on the first end face of the first flange of the first pole, the electrolyte can be prevented from entering between the second surface of the end cover and the first end face of the first pole through the gap between the first sealing ring and the hole wall of the first pole through hole, so that the end cover and the first pole are misdirected, thereby avoiding short circuit in the energy storage device and improving the working reliability of the energy storage device. In addition, it can also avoid double-point failure in the energy storage module after a plurality of energy storage devices are assembled into an energy storage module, and ensure the safety performance of the energy storage module. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the present application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0017] Fig. 1 is a structural schematic diagram of an energy storage module provided by the present application;

[0018] Fig. 2 is a structural schematic diagram of an energy storage device of the energy storage module shown in Fig. 1;

[0019] Fig. 3 is an exploded structural schematic diagram of the energy storage device shown in Fig. 2;

[0020] Fig. 4 is an exploded structural schematic diagram of an end cover assembly shown in Fig. 3 from a first angle;

[0021] Fig. 5 is an exploded structural schematic diagram of the end cover assembly shown in Fig. 4 from a second angle;

[0022] Fig. 6 is a structural schematic diagram of a first upper plastic shown in Fig. 5;

[0023] Fig. 7 is another angle structural schematic diagram of the first upper plastic shown in Fig. 6;

[0024] Fig. 8 is a structural schematic diagram of a second upper plastic shown in Fig. 5;

[0025] Fig. 9 is another angle structural schematic diagram of the second upper plastic shown in Fig. 6;

[0026] Fig. 10 is a structural schematic diagram of a first pole shown in Fig. 5;

[0027] Fig. 11 is a cross-sectional structural schematic diagram of the first pole shown in Fig. 6;

[0028] Fig. 12 is a structural schematic diagram of a second pole shown in Fig. 5;

[0029] Fig. 13 is a cross-sectional structural schematic diagram of the second pole shown in Fig. 6;

[0030] Fig. 14 is a cross-sectional structural schematic diagram of the end cover assembly shown in Fig. 3, in which a first insulation layer of the pole is omitted;

[0031] Fig. 15 is a schematic diagram of a first failure current loop formed by a first kind of double-point failure of the energy storage module shown in Fig. 1, in which arrows indicate the flow direction of the current;

[0032] Fig. 16 is a schematic diagram of a third failure current loop formed by a third kind of double-point failure of the energy storage module shown in Fig. 1, in which arrows indicate the flow direction of the current.

[0033] Explanation of reference signs: 1000-energy storage module, 200-cluster frame, 100-energy storage device, 60-end cover assembly, 90-housing, 80-electrode assembly, 70-adapter piece, 91-housing, 911-accommodation cavity, 92-fifth insulation layer, 2-lower plastic, 10-end cover, 61-explosion-proof valve, 62-explosion-proof sheet, 30-first upper plastic, 30a-second upper plastic, 40-first pole, 40a-second pole, 50-first sealing ring, 50a-second sealing ring, 11-end cover body, 111-first surface, 112-second surface, 113-first mounting groove, 113a-second mounting groove, 114-first through hole, 114a-second through hole, 115-explosion-proof hole, 12-first protruding rib, 12a-second protruding rib, 20-first lower plastic, 20a-second lower plastic, 21-first mounting surface, 22-second mounting surface, 23-first recess, 24-first protruding platform, 25-first pole through hole, 21a-third mounting surface, 22a-fourth mounting surface, 23a-second recess, 24a-second protruding platform, 25a-second pole through hole, 31-first body, 32-first protruding part, 33-first protruding, 311-first surface, 312-second surface, 313-first through hole, 314-first recess ring, 3131-first section, 3132-second section, 31a-second body, 32a-second protruding part, 33a-second protruding, 311a-third surface, 312a-fourth surface, 313a-second through hole, 314a-second recess ring, 3131a-third section, 3132a-fourth section, 51-first sealing hole, 51a-second sealing hole, 41-first flange, 411-first end surface, 413-third outer peripheral surface, 42-first pole body, 421-first section, 422-second section, 423-first connecting surface, 424-first outer peripheral surface, 4231-first sub-connecting surface, 4232-second sub-connecting surface, 44-first insulation layer, 45-third insulation layer, 41a-second flange, 411a-second end surface, 413a-fourth outer peripheral surface, 42a-second pole body, 421a-third section, 422a-fourth section, 423a-second connecting surface, 424a-second outer peripheral surface, 4231a-third sub-connecting surface, 4232a-fourth sub-connecting surface, 44a-second insulation layer, 45a-fourth insulation layer. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0035] Since the energy required by people has strong time and space, in order to reasonably use the energy and improve the energy utilization, it is necessary to store one energy form by a medium or equipment in the same or converted into another energy form, and release it in a specific energy form based on future application needs. At present, the generation of green electricity generally depends on photovoltaic, wind power, water potential, etc., and wind energy and solar energy have strong intermittency and large fluctuation, which will cause unstable power grid, insufficient power at peak power consumption, too much power at low power consumption, and unstable voltage will also cause damage to power, therefore, due to insufficient power demand or insufficient power grid receiving capacity, the problem of "abandoning wind and light" may occur, to solve these problems, it is necessary to rely on energy storage. That is, the electrical energy is converted into other forms of energy by physical or chemical means and stored, and the energy is converted into electrical energy and released when needed. In short, energy storage is similar to a large "power bank", which stores electrical energy when photovoltaic and wind energy is sufficient, and releases the stored electrical power when needed.

[0036] The application provides a kind of electrical equipment, a group of chemical batteries are provided in electrical equipment, mainly using chemical elements in chemical battery as energy storage medium, charge and discharge process is accompanied by chemical reaction or change of energy storage medium, simply speaking, the electrical energy generated by wind energy and solar energy is stored in chemical battery, and the stored electrical quantity is released for use when the use of external electrical energy reaches the peak, or transferred to the place where the electrical quantity is short and used again.

[0037] The electrical equipment provided by the application has a wide range of application scenarios, including (wind and light) power generation side energy storage, power grid side energy storage, base station side energy storage, and user side energy storage. The electrical equipment is usually used in the form of energy storage container, small and medium-sized energy storage cabinet, and household small-sized energy storage box, but it is not limited thereto.

[0038] The electrical equipment includes an energy storage module. The number of energy storage modules can be several. The several energy storage modules are connected in series or parallel.

[0039] It should be noted that "several" in the application refers to two or more. "Conducting" in the application refers to electrical connection.

[0040] Please refer to FIG. 1, which is a structural schematic diagram of an energy storage module 1000 provided by an embodiment of the application. The energy storage module 1000 includes a cluster frame 200, several energy storage devices 100, and several connecting pieces (not shown in the figure). The several energy storage devices 100 are placed in the cluster frame 200, and the several energy storage devices 100 are arranged in sequence. Every two adjacent energy storage devices 100 are connected in series by one connecting piece. In this embodiment, the material of the cluster frame 200 is metal material such as iron or aluminum.

[0041] Please refer to FIG. 2 and FIG. 3. FIG. 2 is a structural schematic diagram of the energy storage device 100 of the energy storage module 1000 shown in FIG. 1. FIG. 3 is an exploded structural schematic diagram of the energy storage device 100 shown in FIG. 2.

[0042] The energy storage device 100 comprises a housing 90, an electrode assembly 80, an electrolyte, a tab 70 and a cap assembly 60. The housing 90 comprises a shell 91. The shell 91 is provided with a receiving cavity 911. The cavity wall of the receiving cavity 911 comprises a bottom wall and a peripheral side wall. The peripheral side wall is protruded from one side surface of the bottom wall along the thickness direction and connected with the edge of the bottom wall. Along the height direction of the shell 91, the end of the peripheral side wall away from the bottom wall encloses the opening of the shell 91. It can be understood that along the height direction of the shell 91, the opening and the bottom wall are located at opposite ends of the receiving cavity 911 along the height direction.

[0043] In the embodiment, the housing 90 further comprises a fifth insulating layer 92. The fifth insulating layer 92 is used to isolate the electrolyte and the cavity wall of the receiving cavity 911. The fifth insulating layer 92 comprises a first part and a second part. The first part completely covers the bottom wall of the receiving cavity 911. The second part is connected with the first part and covers the peripheral side wall of the receiving cavity 911. In one possible implementation, the second part completely covers the peripheral side wall of the receiving cavity 911. In another possible implementation, the second part is about 5 mm lower than the opening.

[0044] The thickness of the fifth insulating layer 92 is 65 μm-150 μm. The conductivity of the fifth insulating layer 92 is 8.0*10 -16 S / m-10.0*10 -16 S / m. The roughness of the fifth insulating layer 92 is less than or equal to 3.2 μm. The fifth insulating layer 92 comprises a coating layer made of polyimide and other materials, but is not limited to the above. In other embodiments, the housing 90 can not comprise the fifth insulating layer 92.

[0045] The electrode assembly 80 and the electrolyte are contained in the receiving cavity 911. The fifth insulating layer 92 isolates the electrolyte and the bottom wall and the peripheral side wall of the receiving cavity 911. The cap assembly 60 covers the opening, and the cap assembly 60 is sealingly connected with the shell 91. The cap assembly 60 is electrically connected with the shell 91. The tab 70 is located between the electrode assembly 80 and the cap assembly 60, and electrically connects the electrode assembly 80 and the cap assembly 60.

[0046] In the embodiment, the energy storage device 100 further comprises an insulating film (not shown in the figure). The insulating film has electrical insulation. The insulating film wraps the outer periphery and the bottom of the shell 91.

[0047] Please refer to FIG. 4 and FIG. 5. FIG. 4 is an exploded structural schematic diagram of the cap assembly 60 shown in FIG. 3 from a first angle. FIG. 5 is an exploded structural schematic diagram of the cap assembly 60 shown in FIG. 4 from a second angle.

[0048] For the convenience of description, the length direction of the end cover assembly 60 shown in FIG. 4 is defined as the X-axis direction, the width direction of the end cover assembly 60 is defined as the Y-axis direction, and the thickness direction of the end cover assembly 60 is defined as the Z-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other. The orientation words such as "upper" and "lower" mentioned in the embodiments of the present application are described according to the orientation shown in FIG. 4 of the drawings, and the orientation toward the positive direction of the Z-axis is "upper", and the orientation toward the negative direction of the Z-axis is "lower", which does not limit the energy storage device 100 in the actual application scenario. The "same", "equal", or "parallel" used in the following text allows a certain tolerance to exist.

[0049] The end cover assembly 60 includes the lower plastic 2 and the end cover 10, and the lower plastic 2 is mounted on the end cover 10. The end cover 10 in the embodiment is an aluminum piece, and the lower plastic 2 is made of plastic material and is insulating. The end cover assembly 60 further includes an explosion-proof valve 61 and an explosion-proof sheet 62. The explosion-proof valve 61 is mounted on the end cover 10. The explosion-proof sheet 62 is mounted on the end cover 10, and the explosion-proof sheet 62 covers the explosion-proof valve 61. The end cover assembly 60 further includes two upper plastics, two pole columns, and two sealing rings. The two upper plastics are a first upper plastic 30 and a second upper plastic 30a, respectively. The two pole columns are a first pole column 40 and a second pole column 40a, respectively. The two sealing rings are a first sealing ring 50 and a second sealing ring 50a, respectively. Specifically, the end cover 10 and the lower plastic 2 are stacked, and the lower plastic 2 is used to insulate the end cover 10 and the electrode assembly 80. The first upper plastic 30 and the second upper plastic 30a are located on the surface of the end cover 10 away from the lower plastic 2. The first pole column 40 is sleeved with the first sealing ring 50. The first pole column 40 penetrates through the lower plastic 2, the end cover 10, and the first upper plastic 30. The second pole column 40a is sleeved with the second sealing ring 50a. The second pole column 40a penetrates through the lower plastic 2, the end cover 10, and the second upper plastic 30a.

[0050] It should be noted that the first pole column 40 can be a positive pole column, and the second pole column 40a can be a negative pole column; or the first pole column 40 can be a negative pole column, and the second pole column 40a can be a positive pole column.

[0051] The end cover 10 includes an end cover body 11. The end cover body 11 is a rectangular plate body. The end cover body 11 includes a first surface 111 and a second surface 112, and the first surface 111 and the second surface 112 are oppositely arranged along the thickness direction of the end cover body 11. The end cover 10 is further provided with a first mounting groove 113 and a second mounting groove 113a. The first mounting groove 113 and the second mounting groove 113a are both concave on the second surface 112 of the end cover 10. Along the length direction of the end cover 10, the first mounting groove 113 and the second mounting groove 113a are respectively located at opposite ends of the end cover 10.

[0052] The end cover body 11 is provided with a first through hole 114, a second through hole 114a and an explosion-proof hole 115. In the thickness direction of the end cover body 11, the first through hole 114 penetrates the first surface 111 of the end cover body 11 and the groove bottom wall of the first mounting groove 113. The second through hole 114a penetrates the first surface 111 of the end cover body 11 and the groove bottom wall of the second mounting groove 113a. The first through hole 114 and the second through hole 114a are respectively located at opposite ends of the end cover body 11 in the length direction. The explosion-proof hole 115 penetrates the first surface 111 and the second surface 112. The explosion-proof hole 115 is located at the middle position of the end cover body 11 in the length direction. The explosion-proof valve 61 is connected with the hole wall of the explosion-proof hole 115. The explosion-proof disc 62 is connected with the hole wall of the explosion-proof hole 115. In the thickness direction of the end cover 10, the explosion-proof disc 62 is closer to the first surface 111 of the end cover body 11 than the explosion-proof valve 61.

[0053] The end cover 10 further includes a first protruding rib 12 and a second protruding rib 12a. The first protruding rib 12 and the second protruding rib 12a are both protruding on the first surface 111. The first protruding rib 12 and the second protruding rib 12a are respectively located at opposite ends of the end cover body 11 in the length direction. The first protruding rib 12 is annular and surrounds the first through hole 114. The second protruding rib 12a is annular and surrounds the second through hole 114a.

[0054] Please continue to refer to FIG. 4 and FIG. 5, the lower plastic 2 is a rectangular plate body. In this embodiment, the lower plastic 2 includes a first lower plastic 20 and a second lower plastic 20a. The first lower plastic 20 includes a first mounting surface 21 and a second mounting surface 22, which are oppositely arranged in the thickness direction of the first lower plastic 20. The first lower plastic 20 is provided with a first recess 23. The first recess 23 is recessed from the second mounting surface 22 to the first mounting surface 21, and a first protruding rib 24 is formed on the first mounting surface 21. The first lower plastic 20 is provided with a first pole through hole 25. In the thickness direction of the first lower plastic 20, the first pole through hole 25 penetrates the surface of the first protruding rib 24 away from the first mounting surface 21 and the groove bottom wall of the first recess 23.

[0055] The second lower plastic 20a includes a third mounting surface 21a and a fourth mounting surface 22a, which are oppositely arranged in the thickness direction of the second lower plastic 20a. The second lower plastic 20a is provided with a second recess 23a. The second recess 23a is recessed from the fourth mounting surface 22a to the third mounting surface 21a, and a second protruding rib 24a is formed on the third mounting surface 21a. The second lower plastic 20a is provided with a second pole through hole 25a. In the thickness direction of the second lower plastic 20a, the second pole through hole 25a penetrates the surface of the second protruding rib 24a away from the third mounting surface 21a and the groove bottom wall of the second recess 23a.

[0056] It should be noted that the first lower plastic 20 and the second lower plastic 20a can be separate structural members or integrally formed structural members.

[0057] Please refer to FIG. 6 and FIG. 7, FIG. 6 is a structural diagram of the first upper plastic shown in FIG. 5; and FIG. 7 is another angle structural diagram of the first upper plastic shown in FIG. 6.

[0058] The first upper plastic 30 includes a first body 31, a first protrusion 32 and a first protruding portion 33. The first body 31 includes a first surface 311 and a second surface 312, which are oppositely arranged along the thickness direction of the first body 31. The first protrusion 32 is protruded from the second surface 312. The first protruding portion 33 is protruded from the first surface 311. The first body 31 is provided with a first through hole 313 and a first recessed ring 314. The first through hole 313 includes a first section 3131 and a second section 3132. Along the thickness direction of the first upper plastic 30, the first section 3131 penetrates through the first protruding portion 33 and a part of the first body 31. The second section 3132 penetrates through the first protrusion 32 and another part of the first body 31. The first section 3131 and the second section 3132 are coaxially arranged and communicate with each other. The aperture of the first section 3131 is larger than the aperture of the second section 3132. It can be understood that an annular step is arranged between the hole wall of the first section 3131 and the hole wall of the second section 3132. The annular step includes a step surface. The wall surface of the hole wall of the first section 3131 and the wall surface of the hole wall of the second section 3132 are connected through the step surface. The first recessed ring 314 is recessed from the second surface 312. The first recessed ring 314 is arranged around the first protrusion 32. In other embodiments, the apertures of the first section 3131 and the second section 3132 of the first through hole 313 can also be the same (allowing a certain size tolerance).

[0059] Please refer to FIG. 8 and FIG. 9, FIG. 8 is a structural diagram of the second upper plastic 30a shown in FIG. 5; and FIG. 9 is another angle structural diagram of the second upper plastic 30a shown in FIG. 6.

[0060] The second upper plastic 30a includes a second body 31a, a second protrusion 32a and a second protruding portion 33a. The second body 31a includes a third surface 311a and a fourth surface 312a, which are oppositely arranged along the thickness direction of the second body 31a. The second protrusion 32a is protruded from the fourth surface 312a. The second protruding portion 33a is protruded from the third surface 311a. The second body 31a is provided with a second through hole 313a and a second concave ring 314a. The second through hole 313a includes a third section 3131a and a fourth section 3132a. Along the thickness direction of the second upper plastic 30a, the third section 3131a penetrates through the second protruding portion 33a and a part of the second body 31a. The fourth section 3132a penetrates through the second protrusion 32a and another part of the second body 31a. The third section 3131a and the fourth section 3132a are coaxially arranged and communicate with each other. The aperture of the third section 3131a is larger than the aperture of the fourth section 3132a. It can be understood that an annular step is arranged between the aperture wall of the third section 3131a and the aperture wall of the fourth section 3132a. The annular step includes a step surface. The wall surface of the aperture wall of the third section 3131a and the wall surface of the aperture wall of the fourth section 3132a are connected by the step surface. The second concave ring 314a is concavely arranged on the fourth surface 312a. The second concave ring 314a surrounds the second protrusion 32a.

[0061] In other embodiments, the apertures of the third section 3131a and the fourth section 3132a of the second through hole 313a can also be the same (allowing a certain size tolerance).

[0062] In the present embodiment, the first upper plastic 30 and the second upper plastic 30a both have electrical insulation. In a possible implementation, the electrical resistance of the first upper plastic 30 is greater than or equal to 55 GΩ. The electrical resistance of the second upper plastic 30a is greater than or equal to 55 GΩ.

[0063] Please continue to refer to FIG. 4 and FIG. 5. The first sealing ring 50 is made of elastic insulating material. The first sealing ring 50 is provided with a first sealing hole 51. The first sealing hole 51 penetrates through the surface of the first sealing ring 50 arranged oppositely along the thickness direction.

[0064] The second sealing ring 50a is made of elastic insulating material. The second sealing ring 50a is provided with a second sealing hole 51a. The second sealing hole 51a penetrates through the surface of the second sealing ring 50a arranged oppositely along the thickness direction.

[0065] Please refer to FIG. 10 and FIG. 11. FIG. 10 is a structural schematic diagram of the first pole 40 shown in FIG. 5; FIG. 11 is a sectional structural schematic diagram of the first pole 40 shown in FIG. 6.

[0066] The first pole 40 includes a first flange 41 and a first pole body 42. The first pole body 42 is connected to the first flange 41.

[0067] The first flange 41 is a plate body. The first flange 41 includes a first end surface 411 and a third peripheral surface 413. The first end surface 411 is a side surface of the first flange 41 along a thickness direction. The third peripheral surface 413 surrounds a central axis of the first flange 41 and is connected to the first end surface 411.

[0068] The first pole body 42 is a column body. The first pole body 42 includes a first segment 421 and a second segment 422. The first segment 421 protrudes from the first end surface 411 of the first flange 41. The second segment 422 is connected to an end of the first segment 421 away from the first flange 41, and the second segment 422 is coaxially arranged with the first segment 421. The diameter of the second segment 422 is greater than the diameter of the first segment 421.

[0069] The first pole body 42 includes a first connecting surface 423 and a first peripheral surface 424. Along a height direction of the first pole 40, the first connecting surface 423 is a surface of the second segment 422 facing away from the first flange 41. The first peripheral surface 424 surrounds a central axis of the first pole body 42 and is connected between the first flange 41 and the first connecting surface 423. It can be understood that the first peripheral surface 424 is an annular surface. Along the height direction of the first pole 40, the first peripheral surface 424 extends in a “Z” shape.

[0070] In other embodiments, the diameters of the first segment 421 and the second segment 422 can also be the same (allowing for a certain size tolerance). It can be understood that, along the height direction of the first pole 40, the first peripheral surface 424 extends in a straight line.

[0071] In this embodiment, the first connecting surface 423 is a partially protruding surface. Specifically, the first connecting surface 423 includes a first sub-connecting surface 4231 and a second sub-connecting surface 4232. Along the height direction of the first pole 40, the second sub-connecting surface 4232 protrudes from the first sub-connecting surface 4231. The first sub-connecting surface 4231 is connected to the periphery of the second sub-connecting surface 4232, and the first sub-connecting surface 4231 and the second sub-connecting surface 4232 are coaxially arranged. In other embodiments, the first connecting surface 423 can also be a flat surface as a whole.

[0072] The first pole 40 further includes a first insulating layer 44 and a third insulating layer 45. The first insulating layer 44 completely covers the first end surface 411 of the first flange 41. The third insulating layer 45 completely covers the first peripheral surface 424 of the first pole body 42. In this embodiment, the first insulating layer 44 can also completely cover the third peripheral surface 413 of the first flange 41. The third insulating layer 45 can also completely cover the first sub-connecting surface 4231 of the first pole body 42.

[0073] The thickness of the first insulating layer 44 is 65 μm-150 μm. The electrical conductivity of the first insulating layer 44 is 8.0*10 -16 S / m-10.0*10-16 S / m. The roughness of the first insulating layer 44 is less than or equal to 3.2 μm. The material of the first insulating layer 44 includes, but is not limited to, a coating layer of polyimide or the like.

[0074] The thickness of the third insulating layer 45 is 65 μm-150 μm. The conductivity of the third insulating layer 45 is 8.0*10 -16 S / m-10.0*10 -16 S / m. The roughness of the third insulating layer 45 is less than or equal to 3.2 μm. The material of the third insulating layer 45 includes, but is not limited to, a coating layer of polyimide or the like.

[0075] Please refer to FIG. 12 and FIG. 13. FIG. 12 is a structural schematic diagram of the second pole column shown in FIG. 5; and FIG. 13 is a sectional structural schematic diagram of the second pole column shown in FIG. 6.

[0076] The second pole column 40a includes a second flange 41a and a second pole column body 42a. The second pole column body 42a is connected to the second flange 41a.

[0077] The second flange 41a is a plate body. The second flange 41a includes a second end surface 411a and a fourth outer circumferential surface 413a. The second end surface 411a is a side surface of the second flange 41a along the thickness direction. The fourth outer circumferential surface 413a surrounds the central axis of the second flange 41a and is connected to the second end surface 411a.

[0078] The second pole column body 42a is a column body. The second pole column body 42a includes a third segment 421a and a fourth segment 422a. The third segment 421a is protruded on the second end surface 411a of the second flange 41a. The fourth segment 422a is connected to the end of the third segment 421a away from the second flange 41a, and the fourth segment 422a is coaxially arranged with the third segment 421a. The diameter of the fourth segment 422a is greater than the diameter of the third segment 421a.

[0079] The second pole column body 42a includes a second connecting surface 423a and a second outer circumferential surface 424a. Along the height direction of the second pole column 40a, the second connecting surface 423a is the surface of the fourth segment 422a facing away from the second flange 41a. The second outer circumferential surface 424a is the surface surrounding the central axis of the second pole column body 42a and connected between the second flange 41a and the second connecting surface 423a. It can be understood that the second outer circumferential surface 424a is an annular surface. Along the height direction of the second pole column 40a, the second outer circumferential surface 424a extends in a “Z” shape.

[0080] In other embodiments, the diameters of the third segment 421a and the fourth segment 422a can also be the same (allowing a certain size tolerance). It can be understood that, along the height direction of the second pole column 40a, the second outer circumferential surface 424a extends in a straight line shape.

[0081] In this embodiment, the second connecting surface 423a is a partially convex surface. Specifically, the second connecting surface 423a includes a third sub connecting surface 4231a and a fourth sub connecting surface 4232a. The fourth sub connecting surface 4232a is convex to the third sub connecting surface 4231a along the height direction of the second pole 40a. The third sub connecting surface 4231a is connected to the outer periphery of the fourth sub connecting surface 4232a, and the third sub connecting surface 4231a and the fourth sub connecting surface 4232a are coaxially arranged. In other embodiments, the second connecting surface 423a can be a flat surface as a whole.

[0082] The second pole 40a further includes a second insulating layer 44a and a fourth insulating layer 45a. The second insulating layer 44a completely covers the second end surface 411a of the second flange 41a. The fourth insulating layer 45a completely covers the second outer peripheral surface 424a of the second pole body 42a. In this embodiment, the second insulating layer 44a can also completely cover the fourth outer peripheral surface 413a of the second flange 41a. The fourth insulating layer 45a can also completely cover the third sub connecting surface 4231a of the second pole body 42a.

[0083] The thickness of the second insulating layer 44a is 65 μm-150 μm. The electrical conductivity of the second insulating layer 44a is 8.0*10 -16 S / m-10.0*10 -16 S / m. The roughness of the second insulating layer 44a is less than or equal to 3.2 μm. The material of the second insulating layer 44a includes but is not limited to a coating layer of polyimide and the like.

[0084] The thickness of the fourth insulating layer 45a is 65 μm-150 μm. The electrical conductivity of the fourth insulating layer 45a is 8.0*10 -16 S / m-10.0*10 -16 S / m. The roughness of the fourth insulating layer 45a is less than or equal to 3.2 μm. The material of the fourth insulating layer 45a includes but is not limited to a coating layer of polyimide and the like.

[0085] Please refer to FIG. 3 and FIG. 14, FIG. 14 is a schematic diagram of the cross-sectional structure of the end cover assembly 60 shown in FIG. 3, wherein the first insulating layer 44 of the first pole 40, the third insulating layer 45, and the second insulating layer 44a of the second pole 40a, and the fourth insulating layer 45a are omitted.

[0086] In this embodiment, the assembly sequence of the end cover assembly 60 is as follows: after the end cover 10 is cleaned and fixed, the explosion-proof valve 61 is welded to the end cover 10, and the explosion-proof sheet 62 is installed. After the first sealing ring 50 is sleeved on the first pole 40, the first pole 40 is installed on the first lower plastic 20, and then the first pole 40 and the first lower plastic 20 are integrally installed on the end cover 10. After the second sealing ring 50a is sleeved on the second pole 40a, the second pole 40a is installed on the second lower plastic 20a, and then the second pole 40a and the second lower plastic 20a are integrally installed on the end cover 10. Finally, the first upper plastic 30 is directly injection molded on the outer periphery of the first pole 40, and the second upper plastic 30a is injection molded on the outer periphery of the second pole 40a.

[0087] In the thickness direction (Z-axis direction) of the end cover assembly 60, the lower plastic 2 is stacked on the second surface 112 of the end cover 10. Specifically, in the length direction (X-axis direction) of the end cover assembly 60, the first lower plastic 20 and the second lower plastic 20a are respectively stacked on opposite ends of the end cover 10. In the thickness direction (Z-axis direction) of the end cover assembly 60, the first mounting surface 21 of the first lower plastic 20 faces the end cover 10. The third mounting surface 21a of the second lower plastic 20a faces the end cover 10. The first mounting surface 21 of the first lower plastic 20 and the third mounting surface 21a of the second lower plastic 20a jointly form one side surface of the lower plastic 2 in the thickness direction. The second mounting surface 22 of the first lower plastic 20 and the fourth mounting surface 22a of the second lower plastic 20a jointly form the other side surface of the lower plastic 2 in the thickness direction.

[0088] The first flange 41 of the first pole 40 is located on the side of the first lower plastic 20 away from the end cover 10 and is crimped to the first lower plastic 20. The first lower plastic 20 is located between the end cover 10 and the first flange 41. The first pole body 42 of the first pole 40 is sequentially provided in the first pole through hole 25 of the first lower plastic 20 and the first through hole 114 of the end cover 10. The first sealing ring 50 is sleeved on the first pole body 42. The first sealing ring 50 is provided in the first pole through hole 25 of the first lower plastic 20 and the first through hole 114 of the end cover 10. The first sealing ring 50 is abutted between the first pole body 42 and the hole wall of the first through hole 114. The hole wall of the first through hole 114 of the end cover 10 extrudes the first sealing ring 50 to deform. The compression amount of the first sealing ring 50 is in the range of 0.65mm-0.85mm. The first sealing ring 50 is spaced apart from the hole wall of the first pole through hole 25. The first body 31 of the first upper plastic 30 is stacked on the first surface 111 of the end cover 10. The first protruding part 32 of the first upper plastic 30 is provided in the first through hole 114 of the end cover 10. The first through hole 313 of the first upper plastic 30 is coaxially provided with the first through hole 114 of the end cover 10. The first pole body 42 of the first pole 40 is provided in the first through hole 313. In the thickness direction (Z-axis direction) of the end cover assembly 60, the second sub-connection surface 4232 of the first pole 40 protrudes from the first upper plastic 30.

[0089] The second flange 41a of the second pole 40a is located on the side of the second lower plastic 20a away from the end cover 10 and is crimped to the second lower plastic 20a. The second lower plastic 20a is located between the end cover 10 and the second flange 41a. The second pole body 42a of the second pole 40a is sequentially provided in the second pole through hole 25a of the second lower plastic 20a and the second through hole 114a of the end cover 10. The second sealing ring 50a is sleeved on the second pole body 42a. The second sealing ring 50a is provided in the second pole through hole 25a of the second lower plastic 20a and the second through hole 114a of the end cover 10. The second sealing ring 50a is abutted between the second pole body 42a and the hole wall of the second through hole 114a. The hole wall of the second through hole 114a of the end cover 10 extrudes the second sealing ring 50a to deform. The compression amount of the second sealing ring 50a is in the range of 0.65mm-0.85mm. The second sealing ring 50a is spaced apart from the hole wall of the second pole through hole 25a. The second body 31a of the second upper plastic 30a is stacked on the first surface 111 of the end cover 10. The second protruding part 32a of the second upper plastic 30a is provided in the second through hole 114a of the end cover 10. The second through hole 313a of the second upper plastic 30a is coaxially provided with the second through hole 114a of the end cover 10. The second pole body 42a of the second pole 40a is provided in the second through hole 313a. In the thickness direction (Z-axis direction) of the end cover assembly 60, the fourth sub-connection surface 4232a of the second pole 40a protrudes from the second upper plastic 30a.

[0090] In this embodiment, the first mounting surface 21 of the first lower plastic 20 abuts against the second surface 112 of the end cover 10. The first boss 24 of the first lower plastic 20 abuts against the groove bottom wall of the first mounting groove 113 of the end cover 10. The first mounting groove 113 of the end cover 10 limits the first boss 24 of the first lower plastic 20, thereby limiting the first lower plastic 20. The first flange 41 of the first pole 40 is pressed against the groove bottom wall of the first recess 23 of the first lower plastic 20. The third mounting surface 21a of the second lower plastic 20a abuts against the second surface 112 of the end cover 10. The second boss 24a of the second lower plastic 20a abuts against the groove bottom wall of the second mounting groove 113a of the end cover 10. The second mounting groove 113a of the end cover 10 limits the second boss 24a of the second lower plastic 20a, thereby limiting the second lower plastic 20a. The second flange 41a of the second pole 40a is pressed against the groove bottom wall of the second recess 23a of the second lower plastic 20a.

[0091] The first upper plastic 30 is injection molded on the first pole 40. The first segment 421 of the first pole body 42 of the first pole 40 is located in the second section 3132 of the first through hole 313 of the first upper plastic 30. The second segment 422 of the first pole body 42 is located in the first section 3131 of the first through hole 313. The first protruding rib 12 of the end cover 10 is embedded in the first recess ring 314 of the first upper plastic 30. The first protruding rib 12 of the end cover 10 limits the first upper plastic 30.

[0092] The second upper plastic 30a is injection molded on the second pole 40a. The third segment 421a of the second pole body 42a of the second pole 40a is located in the fourth section 3132a of the second through hole 313a of the second upper plastic 30a. The fourth segment 422a of the second pole body 42a is located in the third section 3131a of the second through hole 313a. The second protruding rib 12a of the end cover 10 is embedded in the second recess ring 314a of the second upper plastic 30a. The second protruding rib 12a of the end cover 10 limits the second upper plastic 30a.

[0093] Please continue to refer to FIG. 1. A plurality of energy storage devices 100 are sequentially arranged in the cluster frame 200 to form an energy storage module 1000. The first pole 40 of one of the two adjacent energy storage devices 100 and the second pole 40a of the other energy storage device 100 are connected in series through a connecting sheet. The housings 91 of the two adjacent energy storage devices 100 are insulated by an insulating film. The housing 91 of each energy storage device 100 and the cluster frame 200 are also insulated by an insulating film.

[0094] Referring to FIG. 15, FIG. 15 is a schematic diagram of a first failure current loop formed by the first type of double-point failure of the energy storage module shown in FIG. 1, wherein arrows indicate the direction of current flow. It should be noted that the shape and mounting manner of the end cap assembly 60, the first pole 40, and the second pole 40a of each energy storage device 100, and the mounting manner of the plurality of energy storage devices 100 to the cluster frame 200 in FIG. 15 are only used to schematically illustrate the first failure current loop, and do not form a limitation on the shape and mounting manner of the end cap assembly 60, the first pole 40, and the second pole 40a, and the mounting manner of the plurality of energy storage devices 100 to the cluster frame 200.

[0095] In the case where the first insulating layer 44 is not provided on the first pole 40, the electrolyte in the energy storage device 100 can enter between the end cap 10 and the first pole 40 through the gap between the first sealing ring 50 and the hole wall of the first pole through hole 25 of the first lower plastic 20, and simultaneously contact the second surface 112 of the end cap 10 and the first end surface 411 of the first pole 40, thereby causing the end cap 10 and the first pole 40 to be mistakenly conducted. Similarly, in the case where the second insulating layer 44a is not provided on the second pole 40a, the end cap 10 and the second pole 40a can be mistakenly conducted.

[0096] When the end cap 10 and one of the poles of any two energy storage devices 100 (first failure cell and second failure cell, respectively) in the energy storage module 1000 are conducted by the electrolyte (the pole of the first failure cell that is conducted with the end cap 10 is the first conducted pole, and the pole of the second failure cell that is conducted with the end cap 10 is the second conducted pole), and the insulating film outside the two energy storage devices 100 is damaged, the energy storage module 1000 has the first type of double-point failure. The energy storage module 1000 forms a first failure current loop. The path of the first failure current loop is: the current in the first failure cell flows to the end cap 10 through the first conducted pole, and then flows to the housing 91 through the end cap 10; then the current flows to the cluster frame 200 through the housing 91, and then flows to the housing 91 of the second failure cell through the cluster frame 200; the current then flows to the end cap 10 through the housing 91 of the second failure cell, and then flows to the second conducted pole through the end cap 10. Since there are N energy storage devices 100 in series between the first failure cell and the second failure cell, the current of the second conducted pole of the second failure cell flows back to the first conducted pole of the first failure cell through the N energy storage devices 100. Since the current in the first failure current loop is large, a large amount of heat is generated inside all the energy storage devices 100 involved in the first failure current loop, and the energy storage devices 100 can catch fire or even explode.

[0097] It can be understood that there is a gap between the first sealing ring 50 and the hole wall of the first pole post through hole 25. By arranging the first insulating layer 44 on the first end surface 411 of the first flange 41 of the first pole post 40, the electrolyte can be prevented from entering between the second surface 112 of the end cover 10 and the first end surface 411 of the first pole post 40 through the gap between the first sealing ring 50 and the hole wall of the first pole post through hole 25, so as to avoid misdirecting the end cover 10 and the first pole post 40, and further avoid internal short circuit of the energy storage device 100, thereby improving the working reliability of the energy storage device 100. In addition, after a plurality of energy storage devices 100 are assembled into an energy storage module 1000, the first kind of double-point failure in the energy storage module 1000 can be avoided, and the safety performance of the energy storage module 1000 is ensured.

[0098] Similarly, by arranging the second insulating layer 44a on the second end surface 411a of the second flange 41a of the second pole post 40a, the electrolyte can also be prevented from misdirecting the end cover 10 and the second pole post 40a, and further avoiding internal short circuit of the energy storage device 100, thereby improving the working reliability of the energy storage device 100. In addition, after a plurality of energy storage devices 100 are assembled into an energy storage module 1000, the first kind of double-point failure in the energy storage module 1000 can be avoided, and the safety performance of the energy storage module 1000 is ensured.

[0099] In addition, by arranging the third insulating layer 45 on the first outer circumferential surface 424 of the first pole post 40, when the first protruding part 32 of the first upper plastic 30 and the first sealing ring 50 have a gap in the thickness direction of the end cover assembly 60, the electrolyte can also be prevented from entering the gap between the first upper plastic 30 and the first sealing ring 50, so as to avoid misdirecting the end cover 10 and the first pole post 40, and further avoiding internal short circuit of the energy storage device 100, thereby improving the working reliability of the energy storage device 100. In addition, after a plurality of energy storage devices 100 are assembled into an energy storage module 1000, the first kind of double-point failure in the energy storage module 1000 can be avoided, and the safety performance of the energy storage module 1000 is ensured.

[0100] Similarly, by arranging the fourth insulating layer 45a on the second outer circumferential surface 424a of the second pole post 40a, the working reliability of the energy storage device 100 can also be improved. In addition, after a plurality of energy storage devices 100 are assembled into an energy storage module 1000, the first kind of double-point failure in the energy storage module 1000 can be avoided, and the safety performance of the energy storage module 1000 is ensured.

[0101] Please continue to refer to FIG. 15, the upper plastic of the prior art positive side usually has weak electrical property. The end cap 10 and the positive side pole can be conducted through the upper plastic. When the end cap 10 and the positive side pole of any two energy storage devices 100 (the third failed monomer and the fourth failed monomer respectively) in the energy storage module 1000 are conducted through the upper plastic (the pole of the third failed monomer mis-conducted is the third conducted pole, and the pole of the fourth failed monomer mis-conducted is the fourth conducted pole), and the insulation films outside the two energy storage devices 100 are damaged, the energy storage module 1000 occurs the second kind of double-point failure. The energy storage module 1000 forms a second failure current loop. The path of the second failure current loop is similar to that of the first failure current loop, and the difference is only that the third conducted pole of the third failed monomer and the end cap 10 are conducted through the upper plastic. The fourth conducted pole of the fourth failed monomer and the end cap 10 are conducted through the upper plastic. Here, the path of the second failure current loop is not described in detail. Because the current in the second failure current loop is large, a large amount of heat is generated inside all the energy storage devices 100 involved in the second failure current loop, and the energy storage devices 100 can catch fire or even explode.

[0102] It can be understood that the first upper plastic 30 has electrical insulation property, which can avoid the end cap 10 mis-conducted through the first upper plastic 30 and the first pole 40, and further avoid the internal short circuit of the energy storage device 100, thereby improving the working reliability of the energy storage device 100. The second upper plastic 30a has electrical insulation property, which can avoid the end cap 10 mis-conducted through the second upper plastic 30a and the second pole 40a, and further avoid the internal short circuit of the energy storage device 100, thereby improving the working reliability of the energy storage device 100. In addition, it can also avoid the second kind of double-point failure in the energy storage module 1000 after a plurality of energy storage devices 100 are assembled into the energy storage module 1000, thereby ensuring the safety performance of the energy storage module 1000.

[0103] Please refer to FIG. 16, which is a schematic diagram of a third failure current loop formed by the third kind of double-point failure of the energy storage module shown in FIG. 1, wherein the arrow shows the direction of current flow.

[0104] The existing technology can cause the pole to react with the shell 91 electrochemically. When one of the poles of any two energy storage devices 100 (fifth and sixth failed monomers) in the energy storage module 1000 reacts with the shell 91 electrochemically (the pole of the fifth failed monomer reacting with the shell 91 is the fifth conducting pole, and the pole of the sixth failed monomer reacting with the shell 91 is the sixth conducting pole), and the insulating film outside the two energy storage devices 100 is damaged, the third double-point failure occurs in the energy storage module 1000. The third failure current loop is formed in the energy storage module 1000. The path of the third failure current loop is: the fifth conducting pole in the fifth failed monomer reacts with the shell 91 electrochemically to generate a current, the current flows through the fifth conducting pole to the tab electrically connected to the fifth conducting pole, and then flows through the electrolyte to the shell 91; then the current flows through the shell 91 to the cluster frame 200, and then flows through the cluster frame 200 to the shell 91 of the sixth failed monomer; the current then flows through the shell 91 of the sixth failed monomer to the electrolyte, and then flows through the electrolyte to the tab electrically connected to the sixth conducting pole, and then flows to the sixth conducting pole. Since there are N energy storage devices 100 connected in series between the fifth failed monomer and the sixth failed monomer, the current of the sixth conducting pole of the sixth failed monomer then flows through the N energy storage devices 100 back to the fifth conducting pole of the fifth failed monomer. Since the current in the third failure current loop is large, a large amount of heat is generated inside all the energy storage devices 100 involved in the third failure current loop, and the energy storage devices 100 can catch fire or even explode.

[0105] It can be understood that the fifth insulating layer 92 in the present application can isolate the electrolyte from the bottom wall and the peripheral side wall of the accommodation cavity 911, which can prevent the first pole 40 or the second pole 40a from reacting with the shell 91 electrochemically. In addition, it can also prevent the third double-point failure from occurring in the energy storage module 1000 after the plurality of energy storage devices 100 are assembled into the energy storage module 1000, thereby ensuring the safety performance of the energy storage module 1000.

[0106] The above describes the embodiments of the present application in detail, and the specific examples are applied to the principles and implementation modes of the present application. The above description of the embodiments is only used to help understand the method and core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range can be changed; and the above description of the present application should not be understood as a limitation.

Claims

1. An end cap assembly for use in an energy storage device, wherein, The end cover assembly comprises an end cover, a lower plastic, a first sealing ring and a first pole, the end cover comprises a first surface and a second surface arranged opposite to the first surface, the end cover is provided with a first through hole penetrating through the first surface and the second surface; The lower plastic is provided with a first pole through hole penetrating through two surfaces arranged opposite in the thickness direction of the lower plastic; The first pole comprises a first flange, a first pole body and a first insulation layer, the first flange comprises a first end face, the first pole body is protruded from the first end face, and the first insulation layer completely covers the first end face; In the thickness direction of the end cover assembly, the lower plastic is laminated on the second surface, the first pole through hole is coaxially arranged with the first through hole, the first flange is press-bonded on the side of the lower plastic opposite to the end cover, the first pole body is sequentially arranged in the first pole through hole and the first through hole, the first sealing ring is sleeved on the first pole body, and the first sealing ring is sequentially arranged in the first pole through hole and the first through hole, the first sealing ring is abutted between the first pole body and the hole wall of the first through hole, and the first sealing ring is arranged in the hole wall of the first pole through hole.

2. The end cap assembly of claim 1, wherein, The end cover assembly further comprises a second sealing ring and a second pole, the second pole comprises a second flange, a second pole body and a second insulation layer, the second flange comprises a second end face, the second pole body is protruded from the second end face, and the second insulation layer completely covers the second end face; The end cover is further provided with a second through hole penetrating through two surfaces arranged opposite in the thickness direction of the end cover, and in the length direction of the end cover assembly, the second through hole and the first through hole are respectively located at opposite ends of the end cover; The lower plastic is further provided with a second pole through hole penetrating through two surfaces arranged opposite in the thickness direction of the lower plastic, and in the length direction of the end cover assembly, the second pole through hole and the first pole through hole are respectively located at opposite ends of the lower plastic; In the thickness direction of the end cover assembly, the second pole through hole is coaxially arranged with the second through hole, the second flange is press-bonded on the side of the lower plastic opposite to the end cover, the second pole body is sequentially arranged in the second pole through hole and the second through hole, the second sealing ring is sleeved on the second pole body, and the second sealing ring is sequentially arranged in the second pole through hole and the second through hole, the second sealing ring is abutted between the second pole body and the hole wall of the second through hole, and the second sealing ring is arranged in the hole wall of the second pole through hole.

3. The end cap assembly of claim 1, wherein, The end cover assembly further comprises a first upper plastic and a second upper plastic, the first upper plastic comprises a first body and a first protruding part, the first protruding part is protruded from the surface of the first body on one side in the thickness direction, the first upper plastic is provided with a first through hole penetrating through the first body and the first protruding part, and the first upper plastic has electrical insulation. The second upper plastic includes a second body and a second protrusion. The second protrusion protrudes from the surface of the second body along one side of the thickness direction. The second upper plastic has a second through hole that penetrates the second body and the second protrusion. The second upper plastic has electrical insulation properties. The first body is stacked on the first surface, the first protrusion passes through the first through hole, the first through hole is coaxially arranged with the first through hole, and the first pole body passes through the first through hole. The second body is stacked on the first surface, the second protrusion passes through the second through hole, the second through hole is coaxially arranged with the second through hole, and the second pole body passes through the second through hole.

4. The end cap assembly of claim 2, wherein, The thickness of the first insulating layer ranges from 65μm to 150μm, and the thickness of the second insulating layer ranges from 65μm to 150μm.

5. The end cap assembly of claim 4, wherein, The electrical conductivity of the first insulation layer ranges from 8.0*10 -16 S / m - 10.0*10 -16 S / m. The electrical conductivity of the second insulation layer ranges from 8.0*10 -16 S / m - 10.0*10 -16 S / m.

6. The end cap assembly according to claim 2, wherein, The first electrode post further includes a third insulating layer, and the first electrode post body includes a first outer peripheral surface, the third insulating layer completely covering the first outer peripheral surface; The second pole also includes a fourth insulating layer, and the body of the second pole includes a second outer peripheral surface, the fourth insulating layer completely covering the second outer peripheral surface.

7. An energy storage device, wherein, The device includes a housing, an electrode assembly, and an end cap assembly as described in any one of claims 1-6. The housing includes a casing with an opening and a receiving cavity. Along the height direction of the energy storage device, the opening is located on one side of the receiving cavity and communicates with the receiving cavity. The electrode assembly is located in the receiving cavity, and the end cap assembly covers the opening; The energy storage device further includes an electrolyte, which is contained within the containment cavity, and the electrode assembly is immersed in the electrolyte; The outer casing includes a fifth insulating layer that covers the cavity wall of the receiving cavity and is capable of isolating the electrolyte from the cavity wall.

8. The energy storage device of claim 7, wherein, The thickness of the fifth insulating layer ranges from 65 μm to 150 μm, and the electrical conductivity of the fifth insulating layer ranges from 8.0*10 -16 S / m to 10.0*10 -16 S / m.

9. An energy storage module, wherein, It includes a cluster frame and several energy storage devices as described in any one of claims 7-8, wherein the several energy storage devices are placed on the cluster frame and are arranged sequentially, with every two adjacent energy storage devices connected in series.

10. An electrical device, comprising: It includes the energy storage module as described in claim 9, wherein the energy storage module is used to store electrical energy.

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