End cap assembly, energy storage device, and electrical device

Abstract

The application provides an end cover assembly, an energy storage device and an electric equipment, which can reduce the risk of liquid leakage of the energy storage device and improve the safety of the energy storage device. The end cover assembly comprises a lower plastic, a heat shrink nail, a cover plate and a sealing nail. The lower plastic is provided with a protection groove and a liquid inlet hole. The opening of the protection groove is located on the surface in the thickness direction of the lower plastic. The groove bottom wall of the protection groove comprises a first part and a second part connected with each other. The second part is arranged around the first part and is connected between the first part and the groove side wall of the protection groove. In the direction from the groove side wall to the first part, the distance between the second part and the opening of the protection groove gradually increases. The liquid inlet hole is arranged on the first part. The cover plate is installed on one side of the lower plastic in the thickness direction. The cover plate is provided with a liquid injection hole. The liquid injection hole is in communication with the protection groove. The heat shrink nail is in clearance fit with the liquid injection hole. At least part of the heat shrink nail is located in the protection groove and blocks the liquid inlet hole. The sealing nail is located on the side of the heat shrink nail away from the groove bottom wall and seals the liquid injection hole.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to an end cap assembly, an energy storage device, and an electrical appliance. Background Technology

[0002] Secondary batteries and other energy storage devices are widely used as the main power source for electrical equipment due to their recyclability. As the demand for energy storage devices gradually increases, the performance requirements for them are also rising. Existing energy storage devices typically use sealing nails to seal the electrolyte injection hole to prevent leakage. However, during use, these sealing nails gradually age, making it impossible for them to completely seal the injection hole. This allows electrolyte to easily leak out, increasing the risk of leakage and reducing the safety of the energy storage device. Summary of the Invention

[0003] This application provides an end cap assembly, an energy storage device, and an electrical device, which can reduce the risk of leakage in the energy storage device and improve the safety of the energy storage device.

[0004] In a first aspect, this application provides an end cap assembly for use in an energy storage device. The end cap assembly includes a lower plastic part, heat shrink staples, a cover plate, and a sealing staple. The lower plastic part has a protective groove and a liquid inlet hole. The opening of the protective groove is located on the surface of the lower plastic part in the thickness direction. The protective groove includes a groove side wall and a groove bottom wall. The groove bottom wall includes a first part and a second part connected together. The second part is arranged around the first part and is connected between the first part and the groove side wall. From the groove side wall towards the first part, the distance between the second part and the opening of the protective groove gradually increases. The liquid inlet hole is located in the first part and penetrates the first part in the thickness direction. The cover plate is installed on one side of the lower plastic part in the thickness direction. The cover plate has a liquid injection hole that penetrates the cover plate in the thickness direction and communicates with the protective groove. The heat shrink staple is clearance-fitted with the liquid injection hole. At least part of the heat shrink staple is located in the protective groove and blocks the liquid inlet hole. The sealing staple is located on the side of the heat shrink staple away from the groove bottom wall and is installed in the liquid injection hole to seal the liquid injection hole.

[0005] The heat shrink staple is completely located within the protective groove, and the length of the heat shrink staple is greater than the width of the protective groove and less than or equal to the length of the protective groove.

[0006] The heat shrink staple includes a sealing part and an inlet part connected to each other. The sealing part is in clearance fit with the injection hole. The inlet part is connected to one end of the sealing part and blocks the injection hole. The diameter of the inlet part gradually decreases from the sealing part to the inlet part.

[0007] Wherein, along the thickness direction of the end cap assembly, the liquid inlet hole and the liquid injection hole are arranged opposite to each other, the diameter of the liquid inlet hole is larger than the diameter of the end of the inlet portion facing the bottom wall of the tank, and smaller than the diameter of the end of the sealing portion away from the inlet portion; the inlet portion passes through the liquid inlet hole and blocks the liquid inlet hole.

[0008] In particular, the diameter of the liquid inlet hole gradually decreases from the opening of the protective tank towards the bottom wall of the tank.

[0009] When the heat shrink staple undergoes heat shrinkage, the radial shrinkage of the heat shrink staple is equal to or greater than 3%.

[0010] The liquid inlet is provided in multiple locations, and the multiple liquid inlet holes are spaced apart from each other. Along the thickness direction of the end cap assembly, the multiple liquid inlet holes are arranged opposite to the liquid injection hole.

[0011] The lower plastic part includes a plastic body and a protective part. The protective part is connected to one side of the plastic body in the thickness direction and protrudes from the plastic body in a direction away from the plastic body. The opening of the protective groove is located on the surface of the plastic body away from the protective part. The cover plate is installed on the side of the plastic body away from the protective part.

[0012] The injection hole includes an injection section and a stepped section. The stepped section is located on the side of the injection section away from the protective groove and is connected to the injection section. The diameter of the stepped section is larger than the diameter of the injection section. The heat shrink pin is clearance-fitted with the injection section. The sealing pin is installed on the stepped section and seals the stepped section.

[0013] Secondly, this application also provides an energy storage device, including a housing, a battery cell, and an end cap assembly as described in any of the preceding claims. The housing has a receiving cavity that receives the battery cell and an electrolyte. The battery cell is immersed in the electrolyte. The end cap assembly is mounted on the housing and closes the opening of the receiving cavity.

[0014] Thirdly, this application also includes an electrical device comprising the energy storage device described above, wherein the energy storage device supplies power to the electrical device.

[0015] In the end cap assembly provided in this application, when the sealing pin and the cover plate are laser welded, the heat generated by the laser welding is conducted through the cover plate to the heat shrink pin. This causes the heat shrink pin to shrink due to heat, forming a gap fit with the injection hole and falling into the protective groove. Since there is a chance of through-cracks in the welded joint between the sealing pin and the cover plate, the heat shrink pin will not block the helium gas inside the energy storage device during the helium inspection process. The helium gas can escape through the injection hole from the through-cracks, allowing it to be detected by the helium detector. This design enables timely detection of through-cracks or other leakage defects in the welded area between the sealing pin and the cover plate during the helium inspection process, ensuring the accuracy of welding anomaly detection between the sealing pin and the cover plate. This helps reduce the product defect rate of the energy storage device, thereby reducing the risk of leakage during subsequent use or transportation and improving the safety of the energy storage device. Meanwhile, the heat shrink nail shrinks due to the residual heat of the welded sealing nail and falls into the protective groove on its own. After the sealing nail and the cover plate are welded, there is no need for an additional pressing process to make the heat shrink nail fall down, which simplifies the production process of energy storage devices and helps to improve the production efficiency of energy storage devices. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be described below.

[0017] Figure 1 This is a schematic diagram of the energy storage device provided in the embodiments of this application;

[0018] Figure 2 yes Figure 1 The diagram shows the structure of the end cap assembly in the energy storage device.

[0019] Figure 3 yes Figure 2 The diagram shows an exploded view of the end cap assembly in the first embodiment.

[0020] Figure 4 yes Figure 2 The diagram shows a cross-sectional view of the end cap assembly after it has been cut along point AA.

[0021] Figure 5 yes Figure 3 The diagram shows the structure of the lower plastic part of the end cap assembly at another angle.

[0022] Figure 6 yes Figure 5 The diagram below shows the structure of the plastic after it has been cut open along the BB section.

[0023] Figure 7 yes Figure 3 A schematic diagram of the end cap assembly after the cover plate is cut open along CC.

[0024] Figure 8 yes Figure 3 A schematic diagram of the heat shrink pin structure in the end cap assembly shown;

[0025] Figure 9 yes Figure 4 A schematic diagram of a partial cross-sectional structure of the end cap assembly after welding.

[0026] Figure 10 yes Figure 2 The diagram shows a partial structural schematic of the end cap assembly after it has been cut open along point AA in the second embodiment.

[0027] Figure 11 yes Figure 10 The diagram shows the structure of the lower plastic part of the end cap assembly at another angle.

[0028] Figure 12 yes Figure 11 The diagram shows the cross-sectional structure of the plastic after it has been cut along the DD line.

[0029] Figure 13 yes Figure 10 A schematic diagram of the heat shrink pin structure in the end cap assembly shown;

[0030] Figure 14 yes Figure 10 A schematic diagram of the partial structure of the end cap assembly after welding is shown.

[0031] Figure 15 yes Figure 2 The diagram shows a partial structural schematic of the end cap assembly after it has been cut open along point AA in the third embodiment.

[0032] Figure 16 yes Figure 15 The diagram shows the structure of the lower plastic part of the end cap assembly from another angle.

[0033] Figure 17 yes Figure 16 The diagram shows the cross-sectional structure of the lower plastic after it has been cut along EE.

[0034] Figure 18 yes Figure 15 The diagram shows a partial cross-sectional structure of the end cap assembly after welding.

[0035] The names corresponding to the labels in the figure are:

[0036] Energy storage device 100, housing 110, end cap assembly 120, lower plastic 10, cover plate 20, explosion-proof valve 30, heat shrink nail 40, sealing nail 50, pole unit 60, plastic body 11, protective part 12, first surface 111, second surface 112, explosion-proof fence 113, mounting hole 101, protective groove 121, liquid inlet hole 102, clearance groove 103, bottom wall of groove 123, side wall of groove 124, first part 123a, second part 123b, first surface 21, second surface 22, explosion-proof hole 201, liquid injection hole 202, assembly hole 203, liquid injection part 202a, step part 202b, convex ring 23, sealing part 41, inlet part 42, welding part 70, protective plate 80, baffle 125, connecting plate 126. Detailed Implementation

[0037] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0038] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of the energy storage device 100 provided in the embodiments of this application. For ease of description, the length direction of the energy storage device 100 is defined as the X-axis direction, the width direction of the energy storage device 100 is defined as the Y-axis direction, and the height direction of the energy storage device 100 is defined as the Z-axis direction. The X-axis direction, Y-axis direction, and Z-axis direction are all perpendicular to each other.

[0039] Energy storage device 100 includes a housing 110, a battery cell (not shown), and an end cap assembly 120. The housing 110 has a receiving cavity (not shown) with an opening communicating with it. The battery cell is housed within the receiving cavity. The receiving cavity also houses an electrolyte, in which the battery cell is immersed. The end cap assembly 120 is mounted on the housing 110, closing the opening of the receiving cavity and being electrically connected to the battery cell. Exemplarily, the energy storage device 100 is a prismatic battery. In some other embodiments, the energy storage device 100 may also be a cylindrical battery or other types of batteries.

[0040] Please refer to the following: Figure 2 , Figure 3 and Figure 4 , Figure 2 yes Figure 1 The diagram shows the structure of the end cap assembly 120 in the energy storage device 100. Figure 3 yes Figure 2 The end cap assembly 120 shown is an exploded structural diagram in the first embodiment. Figure 4 yes Figure 2 The diagram shows a cross-sectional view of the end cap assembly 120 after it has been cut along line AA. "Cut along line AA" means cut along the plane containing line AA; similar descriptions in the following text can be understood in the same way.

[0041] The end cap assembly 120 includes a lower plastic 10, a cover plate 20, an explosion-proof valve 30, a heat shrink staple 40, a sealing staple 50, and two pole post units 60. The cover plate 20 is installed on one side of the lower plastic 10 in the thickness direction. The explosion-proof valve 30 is installed on the cover plate 20. The heat shrink staple 40 and the two pole post units 60 are both installed on the lower plastic 10 and the cover plate 20, spaced apart from each other and spaced apart from the explosion-proof valve 30. The two pole post units are located on opposite sides of the explosion-proof valve 30. The heat shrink staple 40 is located between the explosion-proof valve 30 and one pole post unit 60. The sealing staple 50 is installed on the cover plate 20, located between the explosion-proof valve 30 and one pole post unit 60, and spaced apart from both the explosion-proof valve 30 and the pole post unit 60. Along the thickness direction of the end cap assembly 120 (the Z-axis direction in the figure), the sealing staple 50 and the heat shrink staple 40 are arranged opposite each other.

[0042] Please refer to the following: Figure 3 , Figure 5 and Figure 6 , Figure 5 yes Figure 3 The diagram shows the structure of the lower plastic 10 in the end cap assembly 120 from another angle. Figure 6 yes Figure 5 The diagram shows the structure of the lower plastic 10 after it is cut open along BB.

[0043] In this embodiment, the lower plastic 10 includes a plastic body 11 and a protective portion 12. The plastic body 11 includes a first surface 111 and a second surface 112. Along the thickness direction of the plastic body 11, the first surface 111 and the second surface 112 are arranged opposite to each other. The first surface 111 is the surface of the plastic body 11 facing the housing 110 of the energy storage device 100, and the second surface 112 is the surface of the plastic body 11 away from the housing 110 of the energy storage device 100. The protective portion 12 is fixedly connected to one side of the plastic body 11 in the thickness direction and protrudes from the plastic body 11 in a direction away from the plastic body 11. Specifically, the protective portion 12 is fixedly connected to the first surface 111 of the plastic body 11 and protrudes from the first surface 111 in a direction away from the first surface 111.

[0044] The lower plastic body 10 also includes an explosion-proof barrier 113. Specifically, the explosion-proof barrier 113 is located in the middle of the plastic body 11 and penetrates the first surface 111 and the second surface 112 of the plastic body 11. The lower plastic body 10 also has two mounting holes 101, a protective groove 121, a liquid inlet 102, and a clearance groove 103. Both mounting holes 101 are located in the plastic body 11. Specifically, both mounting holes 101 penetrate the first surface 111 and the second surface 112 of the plastic body 11 along the thickness direction (Z-axis direction in the figure) and are spaced apart from each other. Along the length direction of the lower plastic body 10 (X-axis direction in the figure), the two mounting holes 101 are located on opposite sides of the explosion-proof barrier 113 and are spaced apart from the explosion-proof barrier 113.

[0045] The opening of the protective groove 121 is located on the surface of the lower plastic 10 in the thickness direction. Specifically, the opening of the protective groove 121 is located on the second surface of the plastic body 11, and the protective groove 121 is recessed from the second surface towards the protective portion 12. The protective groove 121 penetrates both the second surface 112 and the first surface 111 of the plastic body 11. The protective groove 121 can be used to accommodate heat shrink staples 40. For example, the protective groove 121 is an oblong groove. The length direction of the protective groove 121 is parallel to the length direction of the lower plastic 10, and the width direction of the protective groove 121 is parallel to the width direction of the lower plastic 10.

[0046] Specifically, the protective groove 121 includes a bottom wall 123 and a side wall 124 connected to each other. Along the thickness direction of the lower plastic 10, the bottom wall 123 is spaced apart from and opposite to the plastic body 11. The bottom wall 123 includes a first portion 123a and a second portion 123b connected to each other. The first portion 123a is spaced apart from the side wall 124. The second portion 123b surrounds the first portion 123a and connects it to the side wall 124. The side wall 124 is fixedly connected between the bottom wall 123 and the plastic body 11 and surrounds the periphery of the bottom wall 123. Specifically, the side wall 124 is fixedly connected between the second portion 123b and the plastic body 11. Furthermore, in the direction from the side wall 124 towards the first portion 123a, the distance between the second portion 123b and the opening of the protective groove 121 gradually increases. That is, the second part 123b of the bottom wall 123 of the tank is inclined in the direction from the side wall 124 of the tank to the first part 123a.

[0047] In this embodiment, the liquid inlet hole 102 is disposed on the bottom wall 123 of the protective tank 121. The liquid inlet hole 102 penetrates the bottom wall 123 along its thickness direction and communicates with the protective tank 121. Specifically, the liquid inlet hole 102 is disposed in the first portion 123a and penetrates the first portion 123a along its thickness direction. In this embodiment, there can be multiple liquid inlets 102. The multiple liquid inlets 102 are spaced apart from each other. For example, there are three liquid inlets 102. In some other embodiments, the number of liquid inlets 102 can also be one, two, four or more, and the embodiments of this application do not limit this.

[0048] Understandably, during the electrolyte injection of the energy storage device 100, the electrolyte enters the protective tank 121 through the inlet hole 102 of the plastic body 11 of the lower plastic 10, and then flows into the receiving cavity of the housing 110 through multiple inlet holes 102 on the bottom wall of the protective part 12. By providing multiple inlet holes 102 on the bottom wall of the protective part 12, excessive flow of electrolyte into the housing 110 during injection can be prevented, thus avoiding cell failure caused by electrolyte impacting the cells inside the energy storage device 100.

[0049] In addition, the second part 123b of the bottom wall 123 is inclined, which can guide the electrolyte, so that the electrolyte in the protective tank 121 flows naturally to the liquid inlet 102 under the action of gravity, and enters the receiving cavity of the housing 110 through the liquid inlet 102, thus preventing the electrolyte from remaining in the protective tank 121.

[0050] In this embodiment, the clearance groove 103 is disposed around the periphery of the opening of the protective groove 121 and communicates with the protective groove 121. Specifically, the opening of the clearance groove 103 is located on the second surface 112 of the plastic body 11. The clearance groove 103 is recessed from the second surface 112 toward the first surface 111 to communicate with the protective groove 121.

[0051] Please refer to the following: Figure 3 , Figure 4 and Figure 7 , Figure 7 yes Figure 3 The diagram shows the structure of the end cap assembly 120 after the cover plate 20 is cut open along CC.

[0052] The cover plate 20 is installed on one side of the lower plastic 10 in the thickness direction. Specifically, the cover plate 20 is installed on the second surface 112 of the plastic body 11 of the lower plastic 10. For example, the cover plate 20 is made of metal. In this embodiment, the cover plate 20 includes a first surface 21 and a second surface 22. Along the thickness direction of the cover plate 20 body, the first surface 21 and the second surface 22 are arranged opposite to each other. The first surface 21 is the surface of the cover plate 20 facing the lower plastic 10, and the second surface 22 is the surface of the cover plate 20 away from the lower plastic 10.

[0053] The cover plate 20 is also provided with an explosion-proof hole 201, a liquid injection hole 202, and two assembly holes 203. The explosion-proof hole 201, the liquid injection hole 202, and the two assembly holes 203 all penetrate the cover plate 20 along its thickness direction (Z-axis direction in the figure) and are spaced apart from each other. In this embodiment, the explosion-proof hole 201 is located in the middle of the cover plate 20 body. Along the thickness direction of the end cap assembly 120, the explosion-proof hole 201 is opposite to and communicates with the explosion-proof fence 113 of the lower plastic 10. The explosion-proof hole 201 can communicate with the interior of the energy storage device 100 through the explosion-proof fence 113.

[0054] Both mounting holes 203 are located on the edge of the cover plate 20. Along the length of the cover plate 20 (X-axis direction in the figure), the two mounting holes 203 are located on opposite sides of the explosion-proof hole 201. Each mounting hole 203 communicates with a mounting hole 101 of the lower plastic 10 to facilitate the installation of the pole post unit 60, thereby enabling the pole post unit 60 to be assembled with the lower plastic 10 and the cover plate 20.

[0055] The injection hole 202 is located between an assembly hole 203 and an explosion-proof hole 201, and is connected to the inlet hole 102 of the lower plastic 10. Electrolyte can flow sequentially into the protective groove 121 of the protective part 12 through the injection hole 202 of the cover plate 20 and the inlet hole 102 of the lower plastic 10, and then into the housing 110 through the inlet hole 102 provided on the bottom wall 123 of the protective groove 121 (e.g., Figure 1 The cavity shown is used to fill the electrolyte of the energy storage device 100.

[0056] Specifically, the injection hole 202 includes an injection section 202a and a stepped section 202b. The stepped section 202b is located on the side of the injection section 202a opposite to the protective groove 121 of the lower plastic 10, and is connected to the injection section 202a. The diameter of the stepped section 202b is larger than the diameter of the injection section 202a.

[0057] In addition, the cover plate 20 is also provided with a protruding ring 23. Specifically, the protruding ring 23 is provided on the first surface 21 of the cover plate 20 and surrounds the injection hole 202. In this embodiment, the protruding ring 23 protrudes from the first surface 21 of the cover plate 20 in a direction away from the first surface 21. The inner surface of the protruding ring 23 is flush with the hole wall of the injection hole 202. When the cover plate 20 is installed to the lower plastic 10, the protruding ring 23 is installed in the clearance groove 103.

[0058] Please refer to the following: Figure 4 , Figure 8 and Figure 9 , Figure 8 yes Figure 3 The diagram shows the structure of the heat shrink pin 40 in the end cap assembly 120. Figure 9 yes Figure 4 The diagram shows a partial cross-sectional structure of the end cap assembly 120 after welding.

[0059] A heat shrinkable staple 40 passes through the injection hole 202, fitting with it with a clearance, and extends into the protective groove 121. The length of the heat shrinkable staple 40 is greater than the width of the protective groove 121, and less than or equal to the length of the groove. For example, the heat shrinkable staple 40 is generally cylindrical. The heat shrinkable staple 40 can be made of heat-shrinkable materials such as polypropylene (PP), polybutylene terephthalate (PBT), or polyethylene terephthalate (PVT). It should be understood that using materials such as polypropylene, polybutylene terephthalate, or polyethylene terephthalate to make the heat shrinkable staple 40 allows it to shrink upon heating. When the heat shrink pin 40 shrinks due to heat, the radial shrinkage of the heat shrink pin 40 is equal to or greater than 3% to ensure that the heat shrink pin 40 can achieve a clearance fit with the injection hole 202 after being heated and shrunk.

[0060] Specifically, the heat shrinkable staple 40 includes a sealing portion 41 and an inlet portion 42 connected together. Exemplarily, the sealing portion 41 and the inlet portion 42 are integrally formed. The sealing portion 41 is clearance-fitted with the injection hole 202. The inlet portion 42 is connected to one end of the sealing portion 41. In this embodiment, the diameter of the end of the inlet portion 42 away from the sealing portion 41 is smaller than the diameter of the injection hole 202, so that the inlet portion 42 can smoothly pass through the injection hole 202 and extend into the protective groove 121. The diameter of the inlet portion 42 gradually decreases from the sealing portion 41 towards the inlet portion 42. Furthermore, in this embodiment, along the length direction of the heat shrinkable staple 40 (the Z-axis direction shown in the figure), the length of the inlet portion 42 is less than the length of the sealing portion 41, to ensure that the heat shrinkable staple 40 can seal the inlet hole 102 after falling into the protective groove 121.

[0061] When the heat shrink staple 40 is installed onto the cover plate 20, the guide portion 42 first extends into the injection hole 202. At this time, because the diameter of the guide portion 42 gradually decreases, it guides the installation of the heat shrink staple 40, improving the ease of installation into the injection hole 202. During this process, because the diameter of the guide portion 42 is smaller than the diameter of the injection hole 202, when the end of the guide portion 42 near the sealing portion 41 enters the opening of the injection hole 202, the end of the sealing portion 41 near the guide portion 42 is located at the edge of the opening of the injection hole 202. At this time, a pushing force is needed to push the sealing portion 41 so that at least a portion of the sealing portion 41 enters the injection hole 202. At this time, the sealing portion 41 and the injection hole 202 are press-fitted to seal the injection hole 202. Simultaneously, the sealing portion 41 of the heat shrink staple 40 also passes through the inner side of the convex ring 23. When the sealing part 41 is installed onto the cover plate 20, the convex ring 23 can limit the sealing part 41 to prevent it from shifting or tilting, thus ensuring a good sealing effect of the sealing part 41 on the injection hole 202. Furthermore, since the inner surface of the convex ring 23 is flush with the wall of the injection hole 202, it also prevents the convex ring 23 from interfering with the assembly between the sealing part 41 and the cover plate 20, ensuring that the heat shrink nail 40 can be smoothly installed onto the cover plate 20. In this embodiment, after the heat shrink nail 40 and the cover plate 20 are assembled, the end of the heat shrink nail 40 that faces away from the sealing part 41 is spaced apart from the bottom wall 123 of the protective groove 121.

[0062] Please continue reading. Figure 4 and Figure 9 The sealing pin 50 is located on the side of the heat shrink pin 40 facing away from the bottom wall 123 of the groove, and is installed inside the stepped portion 202b of the injection hole 202, sealing the stepped portion 202b of the injection hole 202. For example, the sealing pin 50 is a sealing aluminum pin. In this embodiment, during the laser welding process between the sealing pin 50 and the cover plate 20, such as... Figure 9 As shown, the edge of the sealing pin 50 near the cover plate 20 and the edge of the cover plate 20 near the sealing pin 50 are melted and fused together due to laser energy injection, and then cooled to form a welded portion 70. Alternatively, the end cap assembly 120 may also include the welded portion 70, which connects the cover plate 20 and the sealing pin 50. Specifically, the welded portion 70 is formed by fusing the portion of the sealing pin 50 near the cover plate 20 and the portion of the cover plate 20 near the sealing pin 50.

[0063] In the manufacturing process of the energy storage device 100, after liquid injection, nitrogen gas is introduced into the energy storage device 100, and the injection hole 202 is sealed with heat shrink pins 40. At this time, the heat shrink pins 40 do not shrink, and the sealing part 41 of the heat shrink pins 40 is interference-fitted with the injection hole 202 to seal the injection hole 202, thereby preventing leakage of the energy storage device 100 in subsequent production processes.

[0064] Then, the sealing nail 50 is welded to the cover plate 20. (As follows) Figure 9 As shown, when the sealing nail 50 is laser welded to the cover plate 20, the heat generated by the laser welding is conducted to the heat shrink nail 40 through the cover plate 20. At this time, the heat shrink nail 40 shrinks due to heat, and the sealing part 41 of the heat shrink nail 40 and the injection part 202a of the injection hole 202 change from an interference fit to a clearance fit. That is, after the sealing nail 50 is welded to the cover plate 20, the sealing part 41 of the heat shrink nail 40 and the injection part 202a of the injection hole 202 are in clearance fit. At least a portion of the heat shrink nail 40 is located within the protective groove 121 and blocks the inlet hole 102. In this embodiment, the heat shrink nail 40 is completely located within the protective groove 121. The guide part 42 of the heat shrink nail 40 blocks the inlet hole 102.

[0065] In this embodiment, the heat shrink nail 40 shrinks after heat shrinkage and falls into the protective groove 121 of the protective part 12. It is understood that the second part 123b of the bottom wall 123 of the protective groove 121 is inclined to guide the movement of the heat shrink nail 40. When the heat shrink nail 40 falls, guided by the second part 123b of the bottom wall 123 of the protective groove 121, the heat shrink nail 40 rotates 90° and lies flat on the first part 123a of the bottom wall 123 of the protective groove 121, sealing multiple liquid inlet holes 102. This arrangement prevents electrolyte from entering the protective groove 121 of the lower plastic 10 due to the sloshing of the energy storage device 100, thereby preventing instability in the cell performance of the energy storage device 100 caused by a sudden decrease in electrolyte, and thus helping to ensure the reliable operation of the energy storage device 100. Meanwhile, the heat shrink nail 40 falls into the protective groove 121 of the protective part 12 after it falls, which can also prevent the heat shrink nail 40 from falling directly into the inside of the battery cell and affecting the normal operation of the battery cell, thereby ensuring the good reliability of the energy storage device 100.

[0066] It should be understood that during the welding process between the sealing nail 50 and the cover plate 20, there is a chance that a through-crack will occur in the weld area 70 formed between the sealing nail 50 and the cover plate 20. Since the heat shrink nail 40 shrinks due to heat during welding, and the heat shrink nail 40 and the injection hole 202 are in a clearance fit, when the sealing nail 50 and the cover plate 20 are welded and the energy storage device 100 is subjected to helium testing, the heat shrink nail 40 will not block the helium inside the energy storage device 100. The helium can overflow from the through-crack in the weld area 70 through the injection hole 202, allowing the helium to be detected by the helium detector. With this setup, it is possible to detect through-cracks or other leakage defects in the weld area between the sealing nail 50 and the cover plate 20 in a timely manner during the helium testing process, ensuring the accuracy of welding anomaly detection between the sealing nail 50 and the cover plate 20. This helps reduce the product defect rate of the energy storage device 100, thereby reducing the risk of leakage during subsequent use or transportation and improving the safety of the energy storage device 100. Meanwhile, in this embodiment, the heat shrink nail 40 shrinks due to the residual heat of the welding sealing nail 50 and falls into the protective groove 121 on its own. After the sealing nail 50 and the cover plate 20 are welded, there is no need for an additional process of pressing the sealing nail 50 to make the heat shrink nail 40 fall down, which simplifies the production process of the energy storage device 100 and helps to improve the production efficiency of the energy storage device 100.

[0067] Please refer to it again. Figure 3 and Figure 4 The explosion-proof valve 30 is installed in the explosion-proof hole 201 and fixedly connected to the hole wall of the explosion-proof hole 201. For example, the explosion-proof valve 30 can be fixedly connected to the hole wall of the explosion-proof hole 201 by welding. It is understood that since the explosion-proof hole 201 connects the interior and exterior of the energy storage device 100, when the internal gas pressure of the energy storage device 100 is too high, the explosion-proof valve 30 will rupture under the pressure. The gas inside the energy storage device 100 can then be discharged to the exterior of the energy storage device 100 in a timely manner through the explosion-proof fence 113 of the lower plastic 10 and the explosion-proof hole 201 of the cover plate 20, preventing the energy storage device 100 from exploding and improving the reliability of the energy storage device 100.

[0068] In addition, the end cap assembly 120 may also include a protective plate 80. The protective plate 80 is installed on the cover plate 20 and covers the explosion-proof hole 201. The protective plate 80 is used to protect the explosion-proof valve 30, preventing damage to the explosion-proof valve 30 from the external environment and external forces, thereby preventing the explosion-proof valve 30 from being accidentally activated and ensuring the high reliability of the energy storage device 100.

[0069] Please refer to the following: Figure 10 , Figure 11 and Figure 12 , Figure 10 yes Figure 2The diagram shows a partial structural representation of the end cap assembly 120 after it has been cut along point AA in the second embodiment. Figure 11 yes Figure 10 The diagram shows the structure of the lower plastic 10 in the end cap assembly 120 from another angle. Figure 12 yes Figure 11 The diagram shows the cross-sectional structure of the lower plastic 10 after it is cut along DD.

[0070] The end cap assembly 120 shown in this embodiment differs from the end cap assembly 120 shown in the first embodiment in that it has only one liquid inlet hole 102. The diameter of the liquid inlet hole 102 is larger than the diameter of the end of the inlet portion 42 facing the bottom wall 123 of the tank, and smaller than the diameter of the end of the sealing portion 41 away from the inlet portion 42. This is to hold and limit the heat shrink nail 40 that falls off after heat shrinking, preventing it from falling into the battery cell of the energy storage device 100 and affecting the normal operation of the battery cell. Furthermore, the diameter of the liquid inlet hole 102 gradually decreases from the opening of the protective tank 121 towards the bottom wall 123 of the protective tank 121.

[0071] Please refer to the following: Figure 10 and Figure 13 , Figure 13 yes Figure 10 A schematic diagram of the structure of the heat shrink staple 40 in the end cap assembly 120 shown.

[0072] In this embodiment, the length of the guide portion 42 of the heat shrink staple 40 is greater than the length of the sealing portion 41. This arrangement, on the one hand, further enhances the guiding effect of the guide portion 42, improving the ease with which the heat shrink staple 40 enters the injection hole 202. On the other hand, by increasing the length of the guide portion 42, a longer guide portion of the heat shrink staple 40 can be achieved, preventing adhesive threads from getting stuck on the guide portion 42 and the wall of the injection hole 202. This ensures that the sealing portion 41 of the subsequent heat shrink staple 40 can smoothly enter the injection hole 202 to seal it, ensuring the assembly reliability between the heat shrink staple 40 and the cover plate 20.

[0073] Please see Figure 10 and Figure 14 , Figure 14 yes Figure 10 The diagram shows a partial structural diagram of the end cap assembly 120 after welding.

[0074] In the manufacturing process of the energy storage device 100, after liquid injection into the energy storage device 100, nitrogen gas is introduced into the energy storage device 100, and the liquid injection hole 202 is sealed with a heat shrink pin 40. At this time, the heat shrink pin 40 does not shrink, and the sealing part 41 of the heat shrink pin 40 is interference-fitted with the liquid injection hole 202 to seal the liquid injection hole 202, thereby preventing the energy storage device 100 from leaking liquid in subsequent production processes.

[0075] Then, the sealing nail 50 is welded to the cover plate 20. (As follows) Figure 14 As shown, when the sealing nail 50 is laser welded to the cover plate 20, the heat generated by the laser welding is conducted to the heat shrink nail 40 through the cover plate 20. At this time, the heat shrink nail 40 shrinks due to heat, and the sealing part 41 of the heat shrink nail 40 and the injection hole 202 change from an interference fit to a clearance fit. In this embodiment, the heat shrink nail 40 becomes smaller overall after heat shrinkage. The inlet part 42 passes through the injection hole 102 and blocks the injection hole 102.

[0076] In this embodiment, by making the diameter of the inlet hole 102 larger than the diameter of the end of the inlet portion 42 facing the bottom wall 123 of the tank, and smaller than the diameter of the end of the sealing portion 41 away from the inlet portion 42, on the one hand, the heat shrink pin 40 can fall smoothly into the inlet hole 102 after being heated and contracted, and the heat shrink pin 40 can be tilted to one side in the radial direction of the inlet hole 102, which can reduce the vertical displacement space of the heat shrink pin 40, so that the heat shrink pin 40 is held in the protective groove 121 to seal the inlet hole 102. This can prevent the electrolyte from entering the protective groove 121 of the lower plastic 10 due to the sloshing of the energy storage device 100, and prevent the instability of the cell performance of the energy storage device 100 due to the instantaneous reduction of electrolyte, thereby helping to ensure the good reliability of the energy storage device 100. On the other hand, it can also prevent the heat shrink pin 40 from falling directly into the cell and affecting the normal operation of the cell, thereby also ensuring the good reliability of the energy storage device 100. In addition, as the diameter of the inlet hole 102 gradually decreases, the hole wall surface of the inlet hole 102 can also play a guiding role, making it easier for the guide part 42 to slide into the inlet hole 102, thereby achieving the sealing of the inlet hole 102 by the guide part 42.

[0077] Please refer to the following: Figure 15 , Figure 16 and Figure 17 , Figure 15 yes Figure 2 The diagram shows a partial structural representation of the end cap assembly 120 after it has been cut along line AA in the third embodiment. Figure 16 yes Figure 15 The diagram shows the structure of the lower plastic 10 in the end cap assembly 120 from another angle. Figure 17 yes Figure 16 The diagram shows the cross-sectional structure of the lower plastic 10 after it is cut along EE.

[0078] The end cap assembly 120 shown in this embodiment differs from the end cap assembly 120 shown in the second embodiment above in that the protective part 12 includes a baffle 125 and a plurality of connecting plates 126. Along the thickness direction of the lower plastic 10, the baffle 125 is spaced apart from and opposite to the plastic body 11. The plurality of connecting plates 126 are fixedly connected between the first surface 111 of the plastic body 11 and the baffle 125, and are arranged around the periphery of the liquid inlet hole 102 and spaced apart from each other.

[0079] In this embodiment, multiple connecting plates 126 and baffles 125 enclose a protective groove 121. A liquid inlet 102 is formed between two adjacent connecting plates 126. Alternatively, the liquid inlet 102 can be understood as being located on the sidewall 124 of the protective groove 121 and penetrating the sidewall 124 along its thickness direction. When the energy storage device 100 is injected with electrolyte, the electrolyte flows into the protective groove 121 through the injection hole 202 of the cover plate 20, and then flows into the receiving cavity of the housing 110 through the liquid inlet 102 formed between two adjacent connecting plates 126, thereby realizing the injection of electrolyte into the energy storage device 100.

[0080] Please refer to the following: Figure 15 and Figure 18 , Figure 18 yes Figure 15 The diagram shows a partial cross-sectional structure of the end cap assembly 120 after welding.

[0081] In this embodiment, during the manufacturing process of the energy storage device 100, after liquid injection into the energy storage device 100, nitrogen gas is introduced into the energy storage device 100, and the injection hole 202 is sealed with a heat shrink pin 40. At this time, the heat shrink pin 40 does not shrink, and the sealing part 41 of the heat shrink pin 40 is interference-fitted with the injection hole 202 to seal the injection hole 202, thereby preventing leakage of the energy storage device 100 in subsequent production processes.

[0082] Then, the sealing nail 50 is welded to the cover plate 20. (As follows) Figure 18 As shown, when the sealing pin 50 is laser welded to the cover plate 20, the heat generated by the laser welding is conducted to the heat shrink pin 40 through the cover plate 20. At this time, the heat shrink pin 40 shrinks due to heat, and the sealing part 41 of the heat shrink pin 40 and the injection hole 202 change from an interference fit to a clearance fit. The end of the guide part 42 of the heat shrink pin 40 facing away from the sealing part 41 abuts against the baffle 125 of the protective part 12. This arrangement prevents the heat shrink pin 40 from falling directly into the battery cell and affecting its normal operation, thus ensuring the reliable operation of the energy storage device 100.

[0083] This application also provides an electrical device, which includes the aforementioned energy storage device 100, and the energy storage device 100 supplies power to the electrical device. The electrical device can be a new energy vehicle, a power storage station, a server, or other equipment that requires electricity.

[0084] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Where there is no conflict, the embodiments and features described in the embodiments of this application can be combined with each other. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An end cap assembly for use in an energy storage device, characterized in that, The end cap assembly includes a lower plastic, heat shrink staples, a cover plate, and sealing staples. The lower plastic has a protective groove and a liquid inlet. The opening of the protective groove is located on the surface of the lower plastic in the thickness direction. The protective groove includes a groove sidewall and a groove bottom wall. The groove bottom wall includes a first part and a second part connected together. The second part is arranged around the first part and is connected between the first part and the groove sidewall. From the groove sidewall toward the first part, the distance between the second part and the opening of the protective groove gradually increases. The liquid inlet is located in the first part and penetrates the first part along the thickness direction of the first part. The cover plate is installed on one side of the lower plastic in the thickness direction. The cover plate is provided with a liquid injection hole. The liquid injection hole penetrates the cover plate along the thickness direction and communicates with the protective groove. Along the thickness direction of the end cap assembly, the liquid inlet hole and the liquid injection hole are arranged opposite to each other. The heat shrinkable staple includes a sealing part and an inlet part connected to each other. The sealing part is clearance-fitted with the injection hole. At least a portion of the heat shrinkable staple is located in the protective groove. The inlet part is connected to one end of the sealing part and passes through the injection hole, thus blocking the injection hole. The diameter of the injection hole is larger than the diameter of the end of the inlet part facing the bottom wall of the groove and smaller than the diameter of the end of the sealing part away from the inlet part. The sealing pin is located on the side of the heat shrink pin away from the bottom wall of the tank and is installed in the injection hole to seal the injection hole.

2. The end cap assembly according to claim 1, characterized in that, The diameter of the inlet gradually decreases in the direction from the sealing part to the inlet part.

3. The end cap assembly according to claim 1, characterized in that, The diameter of the liquid inlet gradually decreases from the opening of the protective tank towards the bottom wall of the tank.

4. The end cap assembly according to claim 1, characterized in that, When the heat shrink staple is heat-shrinked, the radial shrinkage of the heat shrink staple is equal to or greater than 3%.

5. The end cap assembly according to claim 1, characterized in that, There are multiple liquid inlet holes, which are spaced apart from each other. Along the thickness direction of the end cap assembly, the multiple liquid inlet holes are all arranged opposite to the injection hole.

6. The end cap assembly according to claim 1, characterized in that, The lower plastic includes a plastic body and a protective part. The protective part is connected to one side of the plastic body in the thickness direction and protrudes from the plastic body in a direction away from the plastic body. The opening of the protective groove is located on the surface of the plastic body opposite to the protective part; The cover plate is installed on the side of the plastic body opposite to the protective part.

7. The end cap assembly according to claim 1, characterized in that, The injection hole includes an injection section and a stepped section. The stepped section is located on the side of the injection section away from the protective groove and is connected to the injection section. The diameter of the stepped section is larger than the diameter of the injection section. The heat shrink staple is fitted with the liquid injection part with a clearance; The sealing pin is installed on the stepped portion and seals the stepped portion.

8. An energy storage device, characterized in that, The device includes a housing, a battery cell, and an end cap assembly as described in any one of claims 1 to 7. The housing has a receiving cavity that receives the battery cell and an electrolyte, the battery cell being immersed in the electrolyte. The end cap assembly is mounted on the housing and closes the opening of the receiving cavity.

9. An electrical appliance, characterized in that, It includes the energy storage device as described in claim 8, wherein the energy storage device supplies power to the electrical equipment.

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