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

Abstract

The invention discloses an end cover assembly, an energy storage device, an energy storage module and electric equipment. Wherein the end cover assembly comprises an end cover, lower plastic, a first sealing ring and a first pole, the end cover comprises a first surface and a second surface, and the end cover is provided with a first through hole; the lower plastic cement is provided with a first pole through hole; the first pole comprises a first flange, a first pole body and a first insulating layer, the first flange comprises a first end face, and the first insulating layer completely covers the first end face; the lower plastic cement is laminated on the second surface, the first flange is crimped on one side, opposite to the end cover, of the lower plastic cement, the first pole body sequentially penetrates through 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 sequentially penetrates through the first pole through hole and the first through hole; the first sealing ring is propped between the first pole body and the hole wall of the through hole; and the first sealing ring and the hole wall of the first pole through hole are arranged at an interval. The working reliability of the energy storage device can be improved.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to end cap assemblies, energy storage devices, energy storage modules and electrical equipment. Background Technology

[0002] A rechargeable battery, also known as a secondary battery or storage battery, is a battery that can be recharged after discharge to reactivate its active materials and continue to be used. The recyclable nature of rechargeable batteries has made them a primary power source for electrical devices. As the demand for rechargeable batteries increases, higher requirements are being placed on their energy density, reliability, and cost. In existing technologies, the end-cap assembly of a rechargeable battery typically includes an end cap and terminals. The terminals pass through the end cap. The end cap and terminals are prone to misalignment, which can cause short circuits in the energy storage device and affect its normal operation. Summary of the Invention

[0003] This application provides an end cap assembly, an energy storage device, an energy storage module, and an electrical device, which can improve the operational reliability of the energy storage device.

[0004] The first aspect of this application provides an end cap assembly for use in an energy storage device. The end cap assembly includes an end cap, a lower plastic, a first sealing ring, and a first pole post. The end cap includes a first surface and a second surface disposed opposite to the first surface. The end cap is provided with a first through hole that penetrates the first surface and the second surface.

[0005] The lower plastic is provided with a first electrode through hole, which penetrates two surfaces of the lower plastic that are disposed opposite to each other along the thickness direction.

[0006] The first pole includes a first flange, a first pole body and a first insulating layer. The first flange includes a first end face, the first pole body protrudes from the first end face, and the first insulating layer completely covers the first end face.

[0007] Along the thickness direction of the end cap assembly, the lower plastic layer is stacked on the second surface. The first pole post through hole is coaxially arranged with the first through hole. The first flange is pressed onto the side of the lower plastic layer facing away from the end cap. The first pole post body is sequentially inserted through the first pole post through hole and the first through hole. The first sealing ring is sleeved on the first pole post body and sequentially inserted through the first pole post through hole and the first through hole. The first sealing ring abuts against the hole wall of the first pole post body and the first through hole. The first sealing ring and the hole wall of the first pole post through hole are spaced apart.

[0008] In one possible implementation, the end cap assembly further includes a second sealing ring and a second pole post. The second pole post includes a second flange, a second pole post body, and a second insulating layer. The second flange includes a second end face, the second pole post body protrudes from the second end face, and the second insulating layer completely covers the second end face.

[0009] The end cap is also provided with a second through hole, which penetrates two surfaces of the end cap that are disposed opposite to each other along the thickness direction. Along the length direction of the end cap assembly, the second through hole and the first through hole are respectively located at opposite ends of the end cap.

[0010] The lower plastic also has a second pole through hole, which penetrates two surfaces of the lower plastic that are arranged opposite to each other along the thickness direction. Along the length direction of the end cap assembly, the second pole through hole and the first pole through hole are located at opposite ends of the lower plastic.

[0011] Along the thickness direction of the end cap assembly, the second pole post through hole and the second through hole are coaxially arranged. The second flange is pressed onto the side of the lower plastic facing away from the end cap. The second pole post body is sequentially inserted through the second pole post through hole and the second through hole. The second sealing ring is sleeved on the second pole post body and sequentially inserted through the second pole post through hole and the second through hole. The second sealing ring abuts against the hole wall of the second pole post body and the second through hole. The second sealing ring and the hole wall of the second pole post through hole are spaced apart.

[0012] In one possible implementation, the end cap assembly further includes a first upper plastic and a second upper plastic. The first upper plastic includes a first body and a first protrusion. The first protrusion protrudes from the surface of the first body on one side along the thickness direction. The first upper plastic has a first through hole that penetrates the first body and the first protrusion. The first upper plastic has electrical insulation properties.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] In one possible implementation, the thickness of the first insulating layer ranges from 65 μm to 150 μm, and the thickness of the second insulating layer ranges from 65 μm to 150 μm.

[0017] In one possible implementation, the conductivity of the first insulating layer ranges from 8.0 × 10⁻⁶. -16 S / m-10.0*10 -16 S / m, the conductivity of the second insulating layer ranges from 8.0*10 -16 S / m-10.0*10 -16 S / m.

[0018] In one possible implementation, the first electrode post further includes a third insulating layer, and the first electrode post body includes a first outer peripheral surface, wherein the third insulating layer completely covers the first outer peripheral surface;

[0019] 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.

[0020] A second aspect of this application provides an energy storage device, including a housing, an electrode assembly, and an end cap assembly as described above. The housing includes a casing, which has 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.

[0021] The electrode assembly is located in the receiving cavity, and the end cap assembly covers the opening;

[0022] The energy storage device further includes an electrolyte, which is contained within the containment cavity, and the electrode assembly is immersed in the electrolyte;

[0023] 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.

[0024] In one possible implementation, the thickness of the fifth insulating layer ranges from 65 μm to 150 μm, and the conductivity of the fifth insulating layer ranges from 8.0 × 10⁻¹⁶ S / m to 10.0 × 10⁻¹⁶ S / m.

[0025] A third aspect of this application provides an energy storage module, including a cluster frame and several energy storage devices as described above. Each energy storage device is externally wrapped with an insulating film. The several energy storage devices are placed on the cluster frame and arranged sequentially, with every two adjacent energy storage devices connected in series.

[0026] A fourth aspect of this application provides an electrical device including an energy storage module as described above, the energy storage module being used to store electrical energy.

[0027] The beneficial effects of this invention are as follows: In this application, there is a gap between the first sealing ring and the wall of the first electrode through-hole. By providing a first insulating layer on the first end face of the first flange of the first electrode, electrolyte can be prevented from entering between the second surface of the end cap and the first end face of the first electrode through the gap between the first sealing ring and the wall of the first electrode through-hole, thus preventing mis-contact between the end cap and the first electrode and avoiding short circuits inside the energy storage device, thereby improving the operational reliability of the energy storage device. Furthermore, it can also prevent double-point failures in the energy storage module after multiple energy storage devices are assembled into an energy storage module, ensuring the safety performance of the energy storage module. Attached Figure Description

[0028] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the energy storage module provided in this application;

[0030] Figure 2 for Figure 1 A schematic diagram of the energy storage device of the energy storage module shown;

[0031] Figure 3 for Figure 2 The diagram shows the exploded structure of the energy storage device.

[0032] Figure 4 for Figure 3 An exploded view of the end cap assembly at the first angle;

[0033] Figure 5 for Figure 4 An exploded view of the end cap assembly at the second angle;

[0034] Figure 6 for Figure 5 The diagram shows the structure of the first upper plastic piece;

[0035] Figure 7 for Figure 6 The diagram shows another angle of the structure of the first upper plastic.

[0036] Figure 8 for Figure 5 The diagram shows the structure of the second upper plastic.

[0037] Figure 9 for Figure 6 The diagram shows another angle of the structure of the second upper plastic.

[0038] Figure 10 for Figure 5 The diagram shows the structure of the first pole piece.

[0039] Figure 11 for Figure 6 A schematic diagram of the cross-sectional structure of the first pole column is shown;

[0040] Figure 12 for Figure 5 The diagram shows the structure of the second pole.

[0041] Figure 13 for Figure 6 A schematic diagram of the cross-sectional structure of the second pole column is shown.

[0042] Figure 14 for Figure 3 The diagram shows a cross-sectional structure of the end cap assembly, where the first insulating layer of the pole post is omitted.

[0043] Figure 15 for Figure 1 The diagram shows the first failure current loop formed when the energy storage module experiences the first type of two-point failure, with the arrows indicating the direction of current flow.

[0044] Figure 16 for Figure 1 The diagram shows the third failure current loop formed by the third type of two-point failure in the energy storage module, where the arrows indicate the direction of current flow.

[0045] Explanation of reference numerals in the attached figures:

[0046] 1000 - Energy storage module, 200 - Cluster rack, 100 - Energy storage device, 60 - End cap assembly, 90 - Housing, 80 - Electrode assembly, 70 - Adapter piece, 91 - Housing, 911 - Receiving cavity, 92 - Fifth insulating layer, 2 - Lower plastic, 10 - End cap, 61 - Explosion-proof valve, 62 - Explosion-proof sheet, 30 - First upper plastic, 30a - Second upper plastic, 40 - First pole post, 40a - Second pole post, 50 - First sealing ring, 50a - Second sealing ring, 11 - End cap body, 111 - First surface, 112 - Second surface, 113 - First mounting groove, 1 13a - Second mounting groove, 114 - First through hole, 114a - Second through hole, 115 - Explosion-proof hole, 12 - First rib, 12a - Second rib, 20 - First lower plastic, 20a - Second lower plastic, 21 - First mounting surface, 22 - Second mounting surface, 23 - First groove, 24 - First boss, 25 - First pole post through hole, 21a - Third mounting surface, 22a - Fourth mounting surface, 23a - Second groove, 24a - Second boss, 25a - Second pole post through hole, 31 - First body, 32 - First protrusion, 33 - First protrusion, 311 - First surface 312 - Second face, 313 - First through hole, 314 - First concave ring, 3131 - First section, 3132 - Second section, 31a - Second body, 32a - Second protrusion, 33a - Second protrusion, 311a - Third face, 312a - Fourth face, 313a - Second through hole, 314a - Second concave ring, 3131a - Third section, 3132a - Fourth section, 51 - First sealing hole, 51a - Second sealing hole, 41 - First flange, 411 - First end face, 413 - Third outer peripheral face, 42 - First pole body, 421 - First segment 422 - Second segment, 423 - First connecting surface, 424 - First outer peripheral surface, 4231 - First sub-connecting surface, 4232 - Second sub-connecting surface, 44 - First insulating layer, 45 - Third insulating layer, 41a - Second flange, 411a - Second end face, 413a - Fourth outer peripheral surface, 42a - Second pole body, 421a - Third segment, 422a - Fourth segment, 423a - Second connecting surface, 424a - Second outer peripheral surface, 4231a - Third sub-connecting surface, 4232a - Fourth sub-connecting surface, 44a - Second insulating layer, 45a - Fourth insulating layer. Detailed Implementation

[0047] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0048] Because the energy we need is highly time- and space-dependent, in order to utilize energy rationally and improve energy efficiency, it is necessary to store one form of energy in the same way or by converting it into another, and then release it in a specific energy form according to future application needs. Currently, the generation of green electricity generally relies on photovoltaic, wind, and hydropower. However, wind and solar energy are generally characterized by strong intermittency and large fluctuations, which can cause grid instability, insufficient power during peak demand periods, and excessive power during off-peak periods. Unstable voltage can also damage the power grid. Therefore, insufficient electricity demand or insufficient grid capacity may lead to the problem of "wind and solar curtailment." Solving these problems requires energy storage. This involves converting electrical energy into other forms of energy through physical or chemical means and storing it, releasing it as electricity when needed. Simply put, energy storage is like a large "power bank," storing electrical energy when photovoltaic and wind power are abundant and releasing the stored electricity when needed.

[0049] This application provides an electrical device with a set of chemical batteries inside. The main purpose of the device is to use the chemical elements in the chemical batteries as energy storage medium. The charging and discharging process is accompanied by the chemical reaction or change of the energy storage medium. Simply put, the electrical energy generated by wind and solar energy is stored in the chemical batteries. When the use of external electrical energy reaches its peak, the stored electrical energy is released for use or transferred to places where electricity is scarce.

[0050] The application scenarios for the electrical equipment provided in this application are quite extensive, including energy storage on the (wind and solar) power generation side, grid-side energy storage, base station-side energy storage, and user-side energy storage. The electrical equipment is typically used in the form of energy storage containers, small and medium-sized energy storage cabinets, and small residential energy storage boxes, but is not limited to these.

[0051] Electrical equipment includes energy storage modules. There can be several energy storage modules. These modules can be connected in series or in parallel.

[0052] It should be noted that "several" in this application refers to two or more. "Conductivity" in this application refers to electrical connection.

[0053] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of the energy storage module 1000 provided in an embodiment of this application. The energy storage module 1000 includes a cluster frame 200, several energy storage devices 100, and several connecting plates (not shown). The several energy storage devices 100 are all placed on the cluster frame 200, and the several energy storage devices 100 are arranged sequentially. Every two adjacent energy storage devices 100 are connected in series through a connecting plate. In this embodiment, the cluster frame 200 is made of metal materials such as iron or aluminum.

[0054] Please refer to the following: Figure 2 and Figure 3 , Figure 2 for Figure 1 A schematic diagram of the structure of the energy storage device 100 of the energy storage module 1000 shown; Figure 3 for Figure 2 The exploded structural diagram of the energy storage device 100 shown.

[0055] The energy storage device 100 includes a housing 90, an electrode assembly 80, an electrolyte, an adapter plate 70, and an end cap assembly 60. The housing 90 includes a shell 91. The shell 91 has a receiving cavity 911. The cavity wall of the receiving cavity 911 includes a bottom wall and peripheral sidewalls. The peripheral sidewalls protrude from one side surface of the bottom wall along its thickness direction and are connected to the edge of the bottom wall. Along the height direction of the shell 91, the end of the peripheral sidewall away from the bottom wall forms an 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.

[0056] In this embodiment, the outer casing 90 further includes a fifth insulating layer 92. The fifth insulating layer 92 is used to isolate the electrolyte from the cavity wall of the receiving cavity 911. The fifth insulating layer 92 includes a first portion and a second portion. The first portion completely covers the bottom wall of the receiving cavity 911. The second portion is connected to the first portion and covers the peripheral sidewall of the receiving cavity 911. In one possible implementation, the second portion completely covers the peripheral sidewall of the receiving cavity 911. In another possible implementation, the second portion is approximately 5 mm below the opening.

[0057] The thickness of the fifth insulating layer 92 is 65μm-150μm. The electrical conductivity of the fifth insulating layer 92 is 8.0*10⁻⁶. -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 includes, but is not limited to, a coating made of materials such as polyimide. In other embodiments, the outer casing 90 may not include the fifth insulating layer 92.

[0058] Electrode assembly 80 and electrolyte are housed within housing cavity 911. A fifth insulating layer 92 isolates the electrolyte from the bottom and peripheral walls of housing cavity 911. End cap assembly 60 covers the opening and is sealed to housing 91. End cap assembly 60 is electrically connected to housing 91. Adapter piece 70 is located between electrode assembly 80 and end cap assembly 60 and electrically connects electrode assembly 80 and end cap assembly 60.

[0059] In this embodiment, the energy storage device 100 further includes an insulating film (not shown). The insulating film has electrical insulation properties. The insulating film covers the outer periphery and bottom of the housing 91.

[0060] Please refer to the following: Figure 4 and Figure 5 , Figure 4 for Figure 3 An exploded view of the end cap assembly 60 at a first angle; Figure 5 for Figure 4 An exploded view of the end cap assembly 60 at a second angle.

[0061] For ease of description, define Figure 4 The length direction of the end cap assembly 60 shown is the X-axis direction, the width direction is the Y-axis direction, and the thickness direction is the Z-axis direction. The X-axis, Y-axis, and Z-axis directions are mutually perpendicular. The directional terms such as "upper" and "lower" mentioned in the description of the embodiments in this application are based on the appendix to the specification. Figure 4 The orientation described herein, with "up" referring to the positive Z-axis direction and "down" referring to the negative Z-axis direction, does not constitute a limitation on the energy storage device 100 in actual application scenarios. The terms "same," "equal," or "parallel" used below are all subject to tolerance.

[0062] The end cap assembly 60 includes a lower plastic 2 and an end cap 10, with the lower plastic 2 mounted on the end cap 10. In this embodiment, the end cap 10 is made of plain aluminum, and the lower plastic 2 is made of plastic and is insulating. The end cap assembly 60 also includes an explosion-proof valve 61 and an explosion-proof plate 62. The explosion-proof valve 61 is mounted on the end cap 10. The explosion-proof plate 62 is mounted on the end cap 10 and covers the explosion-proof valve 61. The end cap assembly 60 also includes two upper plastics, two electrode posts, and two sealing rings. The two upper plastics are a first upper plastic 30 and a second upper plastic 30a. The two electrode posts are a first electrode post 40 and a second electrode post 40a. The two sealing rings are a first sealing ring 50 and a second sealing ring 50a. Specifically, the end cap 10 and the lower plastic 2 are stacked, and the lower plastic 2 is used to insulate the end cap 10 from the electrode assembly 80. The first upper plastic 30 and the second upper plastic 30a are located on the surface of the end cap 10 opposite to the lower plastic 2. The first electrode post 40 is fitted with a first sealing ring 50. The first electrode post 40 passes through the lower plastic 2, the end cap 10, and the first upper plastic 30. The second electrode post 40a is fitted with a second sealing ring 50a. The second electrode post 40a passes through the lower plastic 2, the end cap 10, and the second upper plastic 30a.

[0063] It should be noted that the first terminal 40 can be the positive terminal and the second terminal 40a can be the negative terminal; or the first terminal 40 can be the negative terminal and the second terminal 40a can be the positive terminal.

[0064] The end cap 10 includes an end cap body 11. The end cap body 11 is a rectangular plate. The end cap body 11 includes a first surface 111 and a second surface 112, which are disposed opposite to each other along the thickness direction of the end cap body 11. The end cap 10 is also 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 recessed in the second surface 112 of the end cap 10. Along the length direction of the end cap 10, the first mounting groove 113 and the second mounting groove 113a are respectively located at opposite ends of the end cap 10.

[0065] The end cap body 11 is provided with a first through hole 114, a second through hole 114a, and an explosion-proof hole 115. Along the thickness direction of the end cap body 11, the first through hole 114 penetrates the first surface 111 and the bottom wall of the first mounting groove 113 of the end cap body 11. The second through hole 114a penetrates the first surface 111 and the bottom wall of the second mounting groove 113a of the end cap body 11. The first through hole 114 and the second through hole 114a are located at opposite ends of the end cap body 11 along its length. 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 along the length direction of the end cap body 11. An explosion-proof valve 61 is connected to the hole wall of the explosion-proof hole 115. An explosion-proof plate 62 is connected to the hole wall of the explosion-proof hole 115. Along the thickness direction of the end cap 11, the explosion-proof plate 62 is closer to the first surface 111 of the end cap body 11 than the explosion-proof valve 61.

[0066] The end cap 10 also includes a first rib 12 and a second rib 12a. Both the first rib 12 and the second rib 12a protrude from the first surface 111. The first rib 12 and the second rib 12a are located at opposite ends of the end cap body 11 along its length. The first rib 12 is annular and surrounds the first through hole 114. The second rib 12a is annular and surrounds the second through hole 114a.

[0067] Please continue reading. Figure 4 and Figure 5 The lower plastic 2 is a rectangular plate. 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 arranged opposite to each other along the thickness direction of the first lower plastic 20. The first lower plastic 20 is provided with a first groove 23. The first groove 23 is recessed from the second mounting surface 22 toward the first mounting surface 21, and a first boss 24 is formed by protruding from the first mounting surface 21. The first lower plastic 20 is provided with a first pole post through hole 25. Along the thickness direction of the first lower plastic 20, the first pole post through hole 25 penetrates the surface of the first boss 24 facing away from the first mounting surface 21 and the bottom wall of the first groove 23.

[0068] The second lower plastic 20a includes a third mounting surface 21a and a fourth mounting surface 22a, which are arranged facing away from each other along the thickness direction of the second lower plastic 20a. The second lower plastic 20a has a second groove 23a. The second groove 23a is recessed from the fourth mounting surface 22a toward the third mounting surface 21a, and a second boss 24a is formed protruding from the third mounting surface 21a. The second lower plastic 20a has a second electrode through hole 25a. Along the thickness direction of the second lower plastic 20a, the second electrode through hole 25a penetrates the surface of the second boss 24a facing away from the third mounting surface 21a and the bottom wall of the groove 23a.

[0069] It should be noted that the first lower plastic 20 and the second lower plastic 20a can be separately molded structural parts or integrally molded structural parts.

[0070] Please refer to the following: Figure 6 and Figure 7 , Figure 6 for Figure 5 The diagram shows the structure of the first upper plastic piece; Figure 7 for Figure 6 The diagram shows another angle of the structure of the first upper plastic.

[0071] The first upper plastic 30 includes a first body 31, a first protrusion 32, and a first protrusion 33. The first body 31 includes a first surface 311 and a second surface 312, which are arranged opposite to each other along the thickness direction of the first body 31. The first protrusion 32 protrudes from the second surface 312. The first protrusion 33 protrudes from the first surface 311. The first body 31 is provided with a first through hole 313 and a first concave 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 the first protrusion 33 and a portion of the first body 31. The second section 3132 penetrates the first protrusion 32 and another portion of the first body 31. The first section 3131 and the second section 3132 are coaxially arranged and interconnected. The diameter of the hole in the first section 3131 is larger than the diameter of the hole in the second section 3132. It is understood that an annular step is provided between the hole wall of the first section 3131 and the hole wall of the second section 3132. The annular step includes a stepped surface. The wall surface of the hole in the first section 3131 and the wall surface of the hole in the second section 3132 are connected by the stepped surface. A first concave ring 314 is recessed in the second surface 312. The first concave ring 314 is disposed around the first protrusion 32. In other embodiments, the diameters of the first section 3131 and the second section 3132 of the first through hole 313 may also be the same (allowing for certain dimensional tolerances).

[0072] Please refer to the following: Figure 8 and Figure 9 , Figure 8 for Figure 5The diagram shows the structure of the second upper plastic 30a. Figure 9 for Figure 6 The diagram shows another angle of the structure of the second upper plastic 30a;

[0073] The second upper plastic 30a includes a second body 31a, a second protrusion 32a, and a second protrusion 33a. The second body 31a includes a third surface 311a and a fourth surface 312a, which are arranged opposite to each other along the thickness direction of the second body 31a. The second protrusion 32a protrudes from the fourth surface 312a. The second protrusion 33a protrudes 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 the second protrusion 33a and a portion of the second body 31a. The fourth section 3132a penetrates the second protrusion 32a and another portion of the second body 31a. The third section 3131a and the fourth section 3132a are coaxially arranged and interconnected. The aperture of the third section 3131a is larger than that of the fourth section 3132a. It can be understood that an annular step is provided between the hole wall of the third section 3131a and the hole wall of the fourth section 3132a. The annular step includes a step surface. The wall surface of the hole wall of the third section 3131a and the wall surface of the hole wall of the fourth section 3132a are connected by the step surface. A second concave ring 314a is recessed into the fourth surface 312a. The second concave ring 314a surrounds the second protrusion 32a.

[0074] In other embodiments, the diameters of the third section 3131a and the fourth section 3132a of the second through hole 313a may also be the same (with certain dimensional tolerances allowed).

[0075] In this embodiment, both the first upper plastic 30 and the second upper plastic 30a are electrically insulating. In one possible implementation, the resistance of the first upper plastic 30 is greater than or equal to 55 GΩ. The resistance of the second upper plastic 30a is greater than or equal to 55 GΩ.

[0076] Please continue reading. Figure 4 and Figure 5 The first sealing ring 50 is made of an elastic insulating material. The first sealing ring 50 has a first sealing hole 51. The first sealing hole 51 penetrates the surface of the first sealing ring 50 that faces away from it along the thickness direction.

[0077] The second sealing ring 50a is made of an elastic insulating material. The second sealing ring 50a has a second sealing hole 51a. The second sealing hole 51a penetrates the surface of the second sealing ring 50a that faces away from it along the thickness direction.

[0078] Please refer to the following: Figure 10 and Figure 11 , Figure 10 for Figure 5 The diagram shows the structure of the first pole post 40. Figure 11 for Figure 6 The diagram shows a cross-sectional structure of the first pole post 40.

[0079] The first pole post 40 includes a first flange 41 and a first pole post body 42. The first pole post body 42 is connected to the first flange 41.

[0080] The first flange 41 is a plate. The first flange 41 includes a first end face 411 and a third outer peripheral face 413. The first end face 411 is one side surface of the first flange 41 along the thickness direction. The third outer peripheral face 413 surrounds the central axis of the first flange 41 and is connected to the first end face 411.

[0081] The first pole post body 42 is a column. The first pole post body 42 includes a first segment 421 and a second segment 422. The first segment 421 protrudes from the first end face 411 of the first flange 41. The second segment 422 is connected to the 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 larger than the diameter of the first segment 421.

[0082] The first pole post body 42 includes a first connecting surface 423 and a first outer peripheral surface 424. Along the height direction of the first pole post 40, the first connecting surface 423 is the surface of the second segment 422 facing away from the first flange 41. The first outer peripheral surface 424 is the surface surrounding the central axis of the first pole post body 42 and connecting between the first flange 41 and the first connecting surface 423. It can be understood that the first outer peripheral surface 424 is an annular surface. Along the height direction of the first pole post 40, the first outer peripheral surface 424 extends in a zigzag shape.

[0083] In other embodiments, the diameters of the first segment 421 and the second segment 422 may also be the same (allowing for certain dimensional tolerances). It is understood that the first outer peripheral surface 424 extends in a straight line along the height direction of the first pole post 40.

[0084] 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 post 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 outer 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 may also be entirely planar.

[0085] The first pole post 40 also includes a first insulating layer 44 and a third insulating layer 45. The first insulating layer 44 completely covers the first end face 411 of the first flange 41. The third insulating layer 45 completely covers the first outer peripheral surface 424 of the first pole post body 42. In this embodiment, the first insulating layer 44 may also completely cover the third outer peripheral surface 413 of the first flange 41. The third insulating layer 45 may also completely cover the first sub-connecting surface 4231 of the first pole post body 42.

[0086] The thickness of the first insulating layer 44 is 65μm-150μm. The electrical conductivity of the first insulating layer 44 is 8.0*10⁻⁶. -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 of materials such as polyimide.

[0087] The thickness of the third insulating layer 45 is 65μm-150μm. The electrical 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 of materials such as polyimide.

[0088] Please refer to the following: Figure 12 and Figure 13 , Figure 12 for Figure 5 The diagram shows the structure of the second pole. Figure 13 for Figure 6 The diagram shows the cross-sectional structure of the second pole.

[0089] The second pole 40a includes a second flange 41a and a second pole body 42a. The second pole body 42a is connected to the second flange 41a.

[0090] The second flange 41a is a plate. The second flange 41a includes a second end face 411a and a fourth outer peripheral face 413a. The second end face 411a is one side surface of the second flange 41a along the thickness direction. The fourth outer peripheral face 413a surrounds the central axis of the second flange 41a and is connected to the second end face 411a.

[0091] The second pole body 42a is a cylinder. The second pole body 42a includes a third segment 421a and a fourth segment 422a. The third segment 421a protrudes from the second end face 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 is coaxially arranged with the third segment 421a. The diameter of the fourth segment 422a is larger than the diameter of the third segment 421a.

[0092] The second pole post body 42a includes a second connecting surface 423a and a second outer peripheral surface 424a. Along the height direction of the second pole post 40a, the second connecting surface 423a is the surface of the fourth segment 422a facing away from the second flange 41a. The second outer peripheral surface 424a is the surface surrounding the central axis of the second pole post body 42a and connecting between the second flange 41a and the second connecting surface 423a. It can be understood that the second outer peripheral surface 424a is an annular surface. Along the height direction of the second pole post 40a, the second outer peripheral surface 424a extends in a zigzag shape.

[0093] In other embodiments, the diameters of the third segment 421a and the fourth segment 422a may also be the same (allowing for certain dimensional tolerances). It is understood that the second outer peripheral surface 424a extends in a straight line along the height direction of the second pole post 40a.

[0094] 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. Along the height direction of the second pole post 40a, the fourth sub-connecting surface 4232a protrudes from the third sub-connecting surface 4231a. 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 may also be entirely planar.

[0095] The second pole post 40a further includes a second insulating layer 44a and a fourth insulating layer 45a. The second insulating layer 44a completely covers the second end face 411a of the second flange 41a. The fourth insulating layer 45a completely covers the second outer peripheral surface 424a of the second pole post body 42a. In this embodiment, the second insulating layer 44a may also completely cover the fourth outer peripheral surface 413a of the second flange 41a. The fourth insulating layer 45a may also completely cover the third sub-connecting surface 4231a of the second pole post body 42a.

[0096] The thickness of the second insulating layer 44a is 65μm-150μm. The electrical conductivity of the second insulating layer 44a is 8.0*10⁻⁶. -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 of materials such as polyimide.

[0097] The thickness of the fourth insulating layer 45a is 65μm-150μm. The electrical conductivity of the fourth insulating layer 45a is 8.0*10⁻⁶. -16 S / m-10.0*10 -16S / 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 of polyimide or similar materials.

[0098] Please refer to the following: Figure 3 and Figure 14 , Figure 14 for Figure 3 The schematic diagram of the cross-sectional structure of the end cap assembly 60 shown omits the first insulating layer 44 and the third insulating layer 45 of the first pole post 40, and the second insulating layer 44a and the fourth insulating layer 45a of the second pole post 40a.

[0099] In this embodiment, the assembly sequence of the end cap assembly 60 is as follows: After cleaning and fixing the end cap 10, the explosion-proof valve 61 is welded to the end cap 10, and the explosion-proof plate 62 is installed. After the first sealing ring 50 is fitted onto the first pole post 40, the first pole post 40 is then installed onto the first lower plastic 20, and then the first pole post 40 and the first lower plastic 20 are integrally installed onto the end cap 10. After the second sealing ring 50a is fitted onto the second pole post 40a, the second pole post 40a is then installed onto the second lower plastic 20a, and then the second pole post 40a and the second lower plastic 20a are integrally installed onto the end cap 10. Finally, the first upper plastic 30 is directly injection molded to form the outer periphery of the first pole post 40, and the second upper plastic 30a is injection molded to form the outer periphery of the second pole post 40a.

[0100] Along the thickness direction (Z-axis direction) of the end cap assembly 60, the lower plastic 2 is laminated on the second surface 112 of the end cap 10. Specifically, along the length direction (X-axis direction) of the end cap assembly 60, the first lower plastic 20 and the second lower plastic 20a are laminated on opposite ends of the end cap 10, respectively. Along the thickness direction (Z-axis direction) of the end cap assembly 60, the first mounting surface 21 of the first lower plastic 20 faces the end cap 10. The third mounting surface 21a of the second lower plastic 20a faces the end cap 10. The first mounting surface 21 of the first lower plastic 20 and the third mounting surface 21a of the second lower plastic 20a together form one side surface of the lower plastic 2 along 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 together form the other side surface of the lower plastic 2 along the thickness direction.

[0101] The first flange 41 of the first pole post 40 is located on the side of the first lower plastic 20 facing away from the end cap 10 and is pressed against the first lower plastic 20. The first lower plastic 20 is located between the end cap 10 and the first flange 41. The first pole post body 42 of the first pole post 40 is sequentially inserted through the first pole post through hole 25 of the first lower plastic 20 and the first through hole 114 of the end cap 10. The first sealing ring 50 is sleeved on the first pole post body 42. The first sealing ring 50 is inserted through the first pole post through hole 25 of the first lower plastic 20 and the first through hole 114 of the end cap 10. The first sealing ring 50 abuts against the wall of the first pole post body 42 and the first through hole 114. The wall of the first through hole 114 of the end cap 10 deforms the first sealing ring 50 by compressing it. The compression range of the first sealing ring 50 is 0.65mm-0.85mm. The first sealing ring 50 is spaced apart from the wall of the first pole post through hole 25. The first body 31 of the first upper plastic 30 is stacked on the first surface 111 of the end cap 10. The first protrusion 32 of the first upper plastic 30 passes through the first through hole 114 of the end cap 10. The first through hole 313 of the first upper plastic 30 is coaxially arranged with the first through hole 114 of the end cap 10. The first pole body 42 of the first pole post 40 passes through the first through hole 313. Along the thickness direction (Z-axis direction) of the end cap assembly 60, the second sub-connecting surface 4232 of the first pole post 40 protrudes from the first upper plastic 30.

[0102] The second flange 41a of the second pole post 40a is located on the side of the second lower plastic 20a facing away from the end cap 10 and is pressed against the second lower plastic 20a. The second lower plastic 20a is located between the end cap 10 and the second flange 41a. The second pole post body 42a of the second pole post 40a passes sequentially through the second pole post through hole 25a of the second lower plastic 20a and the second through hole 114a of the end cap 10. The second sealing ring 50a is sleeved on the second pole post body 42a. The second sealing ring 50a passes through the second pole post through hole 25a of the second lower plastic 20a and the second through hole 114a of the end cap 10. The second sealing ring 50a abuts against the wall of the second pole post body 42a and the second through hole 114a. The wall of the second through hole 114a of the end cap 10 deforms the second sealing ring 50a by compressing it. The compression range of the second sealing ring 50a is 0.65mm-0.85mm. The second sealing ring 50a is spaced apart from the wall of the second pole post through hole 25a. The second body 31a of the second upper plastic 30a is stacked on the first surface 111 of the end cap 10. The second protrusion 32a of the second upper plastic 30a passes through the second through hole 114a of the end cap 10. The second through hole 313a of the second upper plastic 30a is coaxially arranged with the second through hole 114a of the end cap 10. The second pole post body 42a of the second pole post 40a passes through the second through hole 313a. Along the thickness direction (Z-axis direction) of the end cap assembly 60, the fourth sub-connecting surface 4232a of the second pole post 40a protrudes from the second upper plastic 30a.

[0103] In this embodiment, the first mounting surface 21 of the first lower plastic 20 abuts against the second surface 112 of the end cap 10. The first boss 24 of the first lower plastic 20 abuts against the bottom wall of the first mounting groove 113 of the end cap 10. The first mounting groove 113 of the end cap 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 post 40 is pressed against the bottom wall of the first groove 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 cap 10. The second boss 24a of the second lower plastic 20a abuts against the bottom wall of the second mounting groove 113a of the end cap 10. The second mounting groove 113a of the end cap 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 post 40a is pressed against the bottom wall of the second groove 23a of the second lower plastic 20a.

[0104] The first upper plastic 30 is injection molded onto the first electrode post 40. The first segment 421 of the first electrode post body 42 of the first electrode post 40 is located at the second section 3132 of the first through hole 313 of the first upper plastic 30. The second segment 422 of the first electrode post body 42 is located at the first section 3131 of the first through hole 313. The first protruding rib 12 of the end cap 10 is embedded in the first concave ring 314 of the first upper plastic 30. The first protruding rib 12 of the end cap 10 serves to limit the position of the first upper plastic 30.

[0105] The second upper plastic 30a is injection molded onto the second electrode post 40a. The third segment 421a of the second electrode post body 42a of the second electrode post 40a is located at the fourth section 3132a of the second through hole 313a of the second upper plastic 30a. The fourth segment 422a of the second electrode post body 42a is located at the third section 3131a of the second through hole 313a. The second protruding rib 12a of the end cap 10 is embedded in the second concave ring 314a of the second upper plastic 30a. The second protruding rib 12a of the end cap 10 serves to limit the position of the second upper plastic 30a.

[0106] Please continue reading. Figure 1 Multiple energy storage devices 100 are arranged sequentially on a cluster frame 200 to form an energy storage module 1000. The first terminal 40 of one energy storage device 100 and the second terminal 40a of the other energy storage device 100 are connected in series via a connecting piece. The housings 91 of adjacent energy storage devices 100 are insulated from each other by an insulating film. The housing 91 of each energy storage device 100 is also insulated from the cluster frame 200 by an insulating film.

[0107] Please see Figure 15 , Figure 15 for Figure 1The diagram shows the first failure current loop formed when the energy storage module experiences a first type of two-point failure. The arrows indicate the direction of current flow. It should be noted that... Figure 15 The shape and mounting method of the end cap assembly 60, the first pole 40, and the second pole 40a of each energy storage device 100, as well as the way in which multiple energy storage devices 100 are mounted on the cluster rack 200, are only used to illustrate the first failure current loop and do not constitute a limitation on the shape and mounting method of the end cap assembly 60, the first pole 40, and the second pole 40a, or the way in which multiple energy storage devices 100 are mounted on the cluster rack 200.

[0108] If the first insulating layer 44 is not provided on the first electrode post 40, the electrolyte in the energy storage device 100 may enter between the end cap 10 and the first electrode post 40 through the gap between the first sealing ring 50 and the wall of the first electrode post through hole 25 of the first lower plastic 20. The electrolyte will simultaneously contact the second surface 112 of the end cap 10 and the first end face 411 of the first electrode post 40, causing a mis-conduction between the end cap 10 and the first electrode post 40. Similarly, if the second insulating layer 44a is not provided on the second electrode post 40a, the end cap 10 and the second electrode post 40a may also experience a mis-conduction.

[0109] When the end caps 10 and one of the terminals of any two energy storage devices 100 (respectively the first and second failed cells) in the energy storage module 1000 are connected by electrolyte (the terminal of the first failed cell connected to the end cap 10 is the first conducting terminal, and the terminal of the second failed cell connected to the end cap 10 is the second conducting terminal), and the insulating film outside the two energy storage devices 100 is damaged, the energy storage module 1000 experiences a first type of two-point failure. The energy storage module 1000 forms a first failure current loop. The path of the first failure current loop is as follows: the current in the first failed cell flows through the first conducting terminal to the end cap 10, and then through the end cap 10 to the housing 91; subsequently, the current flows through the housing 91 to the cluster frame 200, and then through the cluster frame 200 to the housing 91 of the second failed cell; the current then flows through the housing 91 of the second failed cell to the end cap 10, and then through the end cap 10 to the second conducting terminal. Since N energy storage devices 100 are connected in series between the first and second failed cells, the current from the second conducting terminal of the second failed cell flows back to the first conducting terminal of the first failed cell through the N energy storage devices 100. Because 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 may catch fire or even explode.

[0110] It is understandable that there is a gap between the first sealing ring 50 and the wall of the first electrode through hole 25. By providing a first insulating layer 44 on the first end face 411 of the first flange 41 of the first electrode 40, electrolyte can be prevented from entering between the second surface 112 of the end cover 10 and the first end face 411 of the first electrode 40 through the gap between the first sealing ring 50 and the wall of the first electrode through hole 25, thus preventing mis-contact between the end cover 10 and the first electrode 40, thereby avoiding short circuits inside the energy storage device 100 and improving the operational reliability of the energy storage device 100. In addition, it can also prevent the first type of two-point failure from occurring in the energy storage module 1000 after multiple energy storage devices 100 are assembled into an energy storage module 1000, ensuring the safety performance of the energy storage module 1000.

[0111] Similarly, providing a second insulating layer 44a on the second end face 411a of the second flange 41a of the second pole 40a can prevent the electrolyte from causing mis-conduction between the end cap 10 and the second pole 40a, thereby preventing short circuits inside the energy storage device 100 and improving the operational reliability of the energy storage device 100. Furthermore, it can also prevent the first type of two-point failure from occurring in the energy storage module 1000 after multiple energy storage devices 100 are assembled into the energy storage module 1000, ensuring the safety performance of the energy storage module 1000.

[0112] Furthermore, by providing a third insulating layer 45 on the first outer peripheral surface 424 of the first electrode post 40, electrolyte can be prevented from entering the gap between the first protrusion 32 of the first upper plastic 30 and the first sealing ring 50 when there is a gap in the thickness direction of the end cap assembly 60, thus preventing mis-conduction between the end cap 10 and the first electrode post 40 and avoiding short circuits inside the energy storage device 100, thereby improving the operational reliability of the energy storage device 100. In addition, it can also prevent the first type of two-point failure from occurring in the energy storage module 1000 after multiple energy storage devices 100 are assembled into an energy storage module 1000, ensuring the safety performance of the energy storage module 1000.

[0113] Similarly, providing a fourth insulating layer 45a on the second outer peripheral surface 424a of the second pole post 40a can also improve the operational reliability of the energy storage device 100. In addition, it can also prevent the first type of two-point failure from occurring in the energy storage module 1000 after multiple energy storage devices 100 are assembled into an energy storage module 1000, thus ensuring the safety performance of the energy storage module 1000.

[0114] Please continue reading. Figure 15In existing technologies, the plastic coating on the positive electrode side typically has weak electrical properties. The end cap 10 and the positive electrode post are conductive through the plastic coating. When the end cap 10 and the positive electrode post of any two energy storage devices 100 in the energy storage module 1000 (respectively the third and fourth failed cells) are conductive through the plastic coating (the post of the third failed cell that is conductive is the third conductive post, and the post of the fourth failed cell that is conductive is the fourth conductive post), and the insulating film outside these two energy storage devices 100 is damaged, the energy storage module 1000 experiences a second type of two-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, except that the third conductive post of the third failed cell is conductive through the plastic coating to the end cap 10, and the fourth conductive post of the fourth failed cell is conductive through the plastic coating to the end cap 10. The path of the second failure current loop will not be elaborated further here. 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 may catch fire or even explode.

[0115] Understandably, the first upper plastic 30 has electrical insulation properties, which can prevent the end cap 10 from being mis-conductively connected through the first upper plastic 30 and the first terminal 40, thereby preventing a short circuit inside the energy storage device 100 and improving the operational reliability of the energy storage device 100. Similarly, the second upper plastic 30a has electrical insulation properties, which can prevent the end cap 10 from being mis-conductively connected through the second upper plastic 30a and the second terminal 40a, thereby preventing a short circuit inside the energy storage device 100 and improving the operational reliability of the energy storage device 100. Furthermore, it can also prevent a second type of two-point failure from occurring in the energy storage module 1000 after multiple energy storage devices 100 are assembled into the energy storage module 1000, ensuring the safety performance of the energy storage module 1000.

[0116] Please see Figure 16 , Figure 16 for Figure 1 The diagram shows the third failure current loop formed by the third type of two-point failure in the energy storage module, where the arrows indicate the direction of current flow.

[0117] In the prior art, the terminal may undergo an electrochemical reaction with the casing 91. When one of the terminals of any two energy storage devices 100 in the energy storage module 1000 (respectively the fifth and sixth failed cells) undergoes an electrochemical reaction with the casing 91 (the terminal of the fifth failed cell reacting with the casing 91 is the fifth conducting terminal, and the terminal of the sixth failed cell reacting with the casing 91 is the sixth conducting terminal), and the insulating film outside the two energy storage devices 100 is damaged, the energy storage module 1000 experiences a third type of two-point failure. The energy storage module 1000 forms a third failure current loop. The path of the third failure current loop is as follows: The fifth conducting terminal in the fifth failed cell undergoes an electrochemical reaction with the casing 91 to generate current. This current flows through the fifth conducting terminal to the tab electrically connected to it, and then through the electrolyte to the casing 91. Subsequently, the current flows through the casing 91 to the cluster 200, and then through the cluster 200 to the casing 91 of the sixth failed cell. The current then flows through the casing 91 of the sixth failed cell to the electrolyte, and then through the electrolyte to the tab electrically connected to the sixth conducting terminal, and then back to the sixth conducting terminal. Since N energy storage devices 100 are connected in series between the fifth and sixth failed cells, the current in the sixth conducting terminal of the sixth failed cell flows back through these N energy storage devices 100 to the fifth conducting terminal of the fifth failed cell. Because 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, which may cause the energy storage devices 100 to catch fire or even explode.

[0118] Understandably, the fifth insulating layer 92 in this application isolates the electrolyte from the bottom and peripheral walls of the receiving cavity 911, thus preventing an electrochemical reaction between the first electrode 40 or the second electrode 40a and the casing 91. Furthermore, it also prevents a third type of two-point failure from occurring in the energy storage module 1000 after multiple energy storage devices 100 are assembled into the energy storage module 1000, ensuring the safety performance of the energy storage module 1000.

[0119] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An end cap assembly, used in an energy storage device, characterized in that, The end cap assembly includes an end cap, a lower plastic, a first sealing ring, and a first pole post. The end cap includes a first surface and a second surface disposed opposite to the first surface. The end cap is provided with a first through hole, which penetrates the first surface and the second surface. The lower plastic is provided with a first electrode through hole, which penetrates two surfaces of the lower plastic that are disposed opposite to each other along the thickness direction. The first pole includes a first flange, a first pole body and a first insulating layer. The first flange includes a first end face, the first pole body protrudes from the first end face, and the first insulating layer completely covers the first end face. Along the thickness direction of the end cap assembly, the lower plastic layer is stacked on the second surface. The first pole post through hole is coaxially arranged with the first through hole. The first flange is pressed onto the side of the lower plastic layer facing away from the end cap. The first pole post body is sequentially inserted through the first pole post through hole and the first through hole. The first sealing ring is sleeved on the first pole post body and sequentially inserted through the first pole post through hole and the first through hole. The first sealing ring abuts against the hole wall of the first pole post body and the first through hole. The first sealing ring and the hole wall of the first pole post through hole are spaced apart.

2. The end cap assembly according to claim 1, characterized in that, The end cap assembly further includes a second sealing ring and a second pole post. The second pole post includes a second flange, a second pole post body, and a second insulating layer. The second flange includes a second end face. The second pole post body protrudes from the second end face. The second insulating layer completely covers the second end face. The end cap is also provided with a second through hole, which penetrates two surfaces of the end cap that are disposed opposite to each other along the thickness direction. Along the length direction of the end cap assembly, the second through hole and the first through hole are respectively located at opposite ends of the end cap. The lower plastic also has a second pole through hole, which penetrates two surfaces of the lower plastic that are arranged opposite to each other along the thickness direction. Along the length direction of the end cap assembly, the second pole through hole and the first pole through hole are located at opposite ends of the lower plastic. Along the thickness direction of the end cap assembly, the second pole post through hole and the second through hole are coaxially arranged. The second flange is pressed onto the side of the lower plastic facing away from the end cap. The second pole post body is sequentially inserted through the second pole post through hole and the second through hole. The second sealing ring is sleeved on the second pole post body and sequentially inserted through the second pole post through hole and the second through hole. The second sealing ring abuts against the hole wall of the second pole post body and the second through hole. The second sealing ring and the hole wall of the second pole post through hole are spaced apart.

3. The end cap assembly according to claim 1, characterized in that, The end cap assembly further includes a first upper plastic and a second upper plastic. The first upper plastic includes a first body and a first protrusion. The first protrusion protrudes from the surface of the first body on one side along the thickness direction. The first upper plastic is provided with a first through hole, which penetrates the first body and the first protrusion. The first upper plastic has electrical insulation properties. 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 according to claim 2, characterized in that, 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 according to claim 4, characterized in that, The conductivity of the first insulating layer ranges from 8.0 to 10⁻⁶. -16 S / m-10.0*10 -16 S / m, the conductivity of the second insulating layer ranges from 8.0*10 -16 S / m-10.0*10 - 16 S / m.

6. The end cap assembly according to claim 2, characterized in that, 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, characterized in that, 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 according to claim 7, characterized in that, The thickness of the fifth insulating layer ranges from 65 μm to 150 μm, and the conductivity of the fifth insulating layer ranges from 8.0 × 10⁻⁶. -16 S / m-10.0*10 -16 S / m.

9. An energy storage module, characterized in that, 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 appliance, characterized in that, 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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