End cover assembly, energy storage device and electric equipment

Abstract

The invention provides an end cover assembly, an energy storage device and electric equipment, which can reduce the liquid leakage risk of the energy storage device and improve the safety of the energy storage device. The end cover assembly comprises lower plastic, a thermal shrinkage nail, a cover plate and a sealing nail, the lower plastic is provided with a protection groove and a liquid inlet hole, an opening of the protection groove is located in the surface of the lower plastic in the thickness direction, the groove bottom wall of the protection groove comprises a first part and a second part which are connected, and the second part surrounds the first part; the second part is arranged in the protective groove and connected between the first part and the groove side wall of the protective groove, the distance between the second part and the opening of the protective groove is gradually increased in the direction from the groove side wall to the first part, and the liquid inlet hole is formed in the first part; the cover plate is installed on one side of the lower plastic in the thickness direction, and a liquid injection hole is formed in the cover plate and communicates with the protection groove. The thermal shrinkage nail is in clearance fit with the liquid injection hole, and at least part of the thermal shrinkage nail is located in the protection groove and blocks the liquid inlet hole; the sealing nail is located on the side, deviating from the groove bottom wall, of the thermal shrinkage nail and seals the liquid injection hole.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to an end cover assembly, an energy storage device and an electrical equipment. Background Art

[0002] Energy storage devices such as secondary batteries are widely used as the main power source for electrical equipment due to their recyclable characteristics. As the demand for energy storage devices gradually increases, people's performance requirements for them in various aspects are also getting higher and higher. In existing energy storage devices, sealing glue nails are usually used to seal the injection holes of the energy storage devices to prevent leakage of the energy storage devices. However, during the use of the energy storage devices, the sealing glue nails gradually age, making it impossible for the sealing glue nails to completely seal the injection holes, causing the electrolyte inside the energy storage device to easily flow out of the injection holes, increasing the risk of leakage of the energy storage device and reducing the safety of the energy storage device. Summary of the invention

[0003] The present application provides an end cover assembly, an energy storage device, and an electrical device, which can reduce the risk of liquid leakage of the energy storage device and improve the safety of the energy storage device.

[0004] In a first aspect, the present application provides an end cap assembly for use in an energy storage device. The end cover assembly includes a lower plastic, a heat shrink nail, a cover plate and a sealing nail. The lower plastic is provided with a protective groove and a liquid inlet hole. 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 side wall and a groove bottom wall. The groove bottom wall includes a first part and a second part connected to each other. The second part is arranged around the first part and connected between the first part and the groove side wall. In the direction from the groove side wall to the first part, the distance between the second part and the opening of the protective groove gradually increases. The liquid inlet hole is arranged in the first part and penetrates the first part in the thickness direction of the first part; the cover plate is installed on one side of the thickness direction of the lower plastic. The cover plate is provided with a liquid injection hole. The liquid injection hole penetrates the cover plate in the thickness direction of the cover plate and is connected to the protective groove; the heat shrink nail is in gap fit with the liquid injection hole. At least part of the heat shrink nail is located in the protective 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 is installed on the liquid injection hole and seals the liquid injection hole.

[0005] Wherein, the heat shrink nail is completely located in the protective groove, and the length of the heat shrink nail is greater than the width of the protective groove and less than or equal to the length of the protective groove.

[0006] Among them, the heat shrink nail includes a sealing part and an introduction part that are connected to each other. The sealing part is gap-matched with the injection hole. The introduction part is connected to one end of the sealing part and blocks the liquid inlet hole. The diameter of the introduction part gradually decreases in the direction from the sealing part to the introduction part.

[0007] Among them, along the thickness direction of the end cover assembly, the liquid inlet hole and the injection hole are arranged opposite to each other, and the hole diameter of the liquid inlet hole is larger than the diameter of one end of the introduction part facing the bottom wall of the groove, and smaller than the diameter of one end of the sealing part away from the introduction part; the introduction part passes through the liquid inlet hole and blocks the liquid inlet hole.

[0008] Wherein, the aperture of the liquid inlet hole gradually decreases in the direction from the opening of the protection groove to the bottom wall of the groove.

[0009] Wherein, when the heat shrink nail is heat-shrunk, the radial shrinkage amount of the heat shrink nail is equal to or greater than 3%.

[0010] There are a plurality of liquid inlet holes, and the plurality of liquid inlet holes are arranged at intervals from each other. Along the thickness direction of the end cover assembly, the plurality of liquid inlet holes are arranged opposite to the liquid injection hole.

[0011] Among them, 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 the 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] Among them, the injection hole includes an injection part and a step part, the step part is located on the side of the injection part away from the protective groove and is connected with the injection part, and the diameter of the step part is larger than the diameter of the injection part; the heat shrink nail is gap-fitted with the injection part; the sealing nail is installed on the step part and seals the step part.

[0013] In a second aspect, the present application also provides an energy storage device, comprising a shell, a battery cell and an end cap assembly as described in any one of the above items, wherein the shell is provided with a receiving cavity, the receiving cavity receives the battery cell and an electrolyte, the battery cell is immersed in the electrolyte, and the end cap assembly is mounted on the shell and closes the opening of the receiving cavity.

[0014] In a third aspect, the present application also includes an electrical device, including the energy storage device described above, and the energy storage device supplies power to the electrical device.

[0015] In the end cover assembly provided by the present application, when the sealing pin and the cover plate are laser welded, the heat generated by the laser welding is conducted to the heat shrink pin through the cover plate, so that the heat shrink pin shrinks due to the heat and forms a gap with the injection hole, and falls into the protective groove. Since the fusion portion formed by the welding between the sealing pin and the cover plate has a probability of generating a through crack, when the energy storage device is subjected to a helium inspection process, the heat shrink pin will not block the helium inside the energy storage device, and the helium can overflow from the through crack through the injection hole, so that the helium is detected by the helium detector. Under this setting, it is possible to timely detect whether there are through cracks or other leakage defects in the welding area between the sealing pin and the cover plate during the helium inspection process, thereby ensuring the accuracy of the detection of welding anomalies between the sealing pin and the cover plate, helping to reduce the product defect rate of the energy storage device, and thereby reducing the risk of leakage of the energy storage device during subsequent use or transportation, thereby improving the safety of the energy storage device. At the same time, the heat shrink nails shrink due to the residual heat of the welding sealing nails and fall into the protective groove by themselves. After the sealing nails and the cover plate are welded, there is no need to press the sealing nails additionally to make the heat shrink nails fall, which can simplify the production process of the energy storage device and help improve the production efficiency of the energy storage device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solution of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be described below.

[0017] Figure 1 is a schematic diagram of the structure of the energy storage device provided in an embodiment of the present application;

[0018] Figure 2 yes Figure 1 A schematic diagram of the structure of the end cover assembly in the energy storage device shown;

[0019] Figure 3 yes Figure 2 The end cap assembly is a schematic diagram of an exploded structure in a first embodiment;

[0020] Figure 4 yes Figure 2 The cross-sectional structure diagram of the end cover assembly after being cut along AA;

[0021] Figure 5 yes Figure 3 A schematic diagram of the structure of the lower plastic in the end cover assembly shown at another angle;

[0022] Figure 6 yes Figure 5 The structure diagram of the lower plastic after being cut open along BB;

[0023] Figure 7 yes Figure 3 The schematic diagram of the structure of the end cover assembly after the cover plate is cut along CC;

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

[0025] Fig. 9 yes Figure 4 A schematic diagram of a partial cross-sectional structure of the end cover assembly after welding is shown;

[0026] Fig.10 yes Figure 2 The end cover assembly shown is a partial structural schematic diagram of the second embodiment after being cut along AA;

[0027] Fig.11 yes Fig.10 A schematic diagram of the structure of the lower plastic in the end cover assembly shown at another angle;

[0028] Fig.12 yes Fig.11 The cross-sectional structure diagram of the lower plastic after being cut along DD is shown.

[0029] Fig.13 yes Fig.10 A schematic diagram of the structure of the heat shrink nail in the end cover assembly shown;

[0030] Fig.14 yes Fig.10 A schematic diagram of a portion of the structure of the end cover assembly after welding is shown;

[0031] Fig.15 yes Figure 2 The end cover assembly is shown as a partial structural schematic diagram of the third embodiment after being cut along AA;

[0032] Fig.16 yes Fig.15 A schematic diagram of the structure of the lower plastic in the end cover assembly shown at another angle;

[0033] Fig.17 yes Fig.16 The schematic diagram of the cross-sectional structure of the lower plastic after being cut along EE;

[0034] Fig.18 yes Fig.15 The schematic diagram of the partial cross-sectional structure of the end cover assembly after welding is shown.

[0035] The names corresponding to the reference numerals in the figures are:

[0036] Energy storage device 100, shell 110, end cover 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, avoidance groove 103, groove bottom wall 123, groove side wall 124, first part 123a, second part 123b, first surface 21, second surface 22, explosion-proof hole 201, injection hole 202, assembly hole 203, injection part 202a, step part 202b, convex ring 23, sealing part 41, introduction part 42, welding part 70, protective sheet 80, baffle 125, connecting plate 126. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0038] See also Figure 1 , Figure 1 1 is a schematic diagram of the structure of the energy storage device 100 provided in an embodiment of the present application. For the convenience 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, the Y-axis direction, and the Z-axis direction are perpendicular to each other.

[0039] The energy storage device 100 includes a shell 110, a battery cell (not shown) and an end cap assembly 120. The shell 110 has a receiving cavity (not shown), and an opening is connected to the receiving cavity. The battery cell is received in the receiving cavity. The receiving cavity is also used to receive an electrolyte, and the battery cell is immersed in the electrolyte. The end cap assembly 120 is mounted on the shell 110, and closes the opening of the receiving cavity of the shell 110, and is electrically connected to the battery cell. Exemplarily, the energy storage device 100 is a square battery. In some other embodiments, the energy storage device 100 may also be a cylindrical battery or other batteries.

[0040] Please refer to Figure 2 , Figure 3 and Figure 4 , Figure 2 yes Figure 1 The schematic diagram of the structure of the end cover assembly 120 in the energy storage device 100 is shown. Figure 3 yes Figure 2 The end cap assembly 120 is a schematic diagram of an exploded structure in the first embodiment. Figure 4 yes Figure 2 The cross-sectional structure diagram of the end cap assembly 120 is shown after being cut along AA. Herein, "cut along AA" means cutting along the plane where the AA line is located, and 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 nail 40, a sealing nail 50 and two pole 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 nail 40 and the two pole units 60 are both installed on the lower plastic 10 and the cover plate 20, and are spaced apart from each other, and are both spaced apart from the explosion-proof valve 30. Among them, the two pole guides are respectively located on opposite sides of the explosion-proof valve 30. The heat shrink nail 40 is located between the explosion-proof valve 30 and one pole unit 60. The sealing nail 50 is installed on the cover plate 20, and is located between the explosion-proof valve 30 and one pole unit 60, and is spaced apart from the explosion-proof valve 30 and one pole unit 60. Along the thickness direction of the end cap assembly 120 (Z-axis direction shown in the figure), the sealing nail 50 and the heat shrink nail 40 are relatively arranged.

[0042] Please refer to Figure 3 , Figure 5 and Figure 6 , Figure 5 yes Figure 3 The schematic diagram of the structure of the lower plastic 10 in the end cap assembly 120 at another angle is shown. Figure 6 yes Figure 5 The structure diagram of the lower plastic 10 after being cut open along BB is shown.

[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 shell 110 of the energy storage device 100, and the second surface 112 is the surface of the plastic body 11 away from the shell 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 10 also includes an explosion-proof fence 113. Specifically, the explosion-proof fence 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 10 is also provided with two mounting holes 101, a protective groove 121, a liquid inlet hole 102 and an avoidance groove 103. Among them, the two mounting holes 101 are both provided in the plastic body 11. Specifically, the two mounting holes 101 penetrate the first surface 111 and the second surface 112 of the plastic body 11 along the thickness direction of the plastic body 11 (Z-axis direction in the figure), and are spaced apart from each other. Along the length direction of the lower plastic 10 (X-axis direction in the figure), the two mounting holes 101 are respectively located on opposite sides of the explosion-proof fence 113, and are spaced apart from the explosion-proof fence 113.

[0045] The opening of the protective groove 121 is located on the surface in the thickness direction of the lower plastic 10. 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 to the protective portion 12. The protective groove 121 passes through the second surface 112 and the first surface 111 of the plastic body 11. The protective groove 121 can be used to accommodate the heat shrink nail 40. Exemplarily, the protective groove 121 is a waist-shaped 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 groove bottom wall 123 and a groove side wall 124 connected to each other. Along the thickness direction of the lower plastic 10, the groove bottom wall 123 is spaced apart from the plastic body 11 and arranged oppositely. Among them, the groove bottom wall 123 includes a first part 123a and a second part 123b connected to each other. Among them, the first part 123a is spaced apart from the groove side wall 124. The second part 123b is arranged around the first part 123a and connected between the first part 123a and the groove side wall 124. The groove side wall 124 is fixedly connected between the groove bottom wall 123 and the plastic body 11, and is arranged around the peripheral side of the groove bottom wall 123. Specifically, the groove side wall 124 is fixedly connected between the second part 123b and the plastic body 11. In addition, in the direction from the groove side wall 124 to the first part 123a, the distance between the second part 123b and the opening of the protective groove 121 gradually increases. That is, the second portion 123 b of the groove bottom wall 123 is inclined in a direction from the groove side wall 124 to the first portion 123 a .

[0047] In the present embodiment, the liquid inlet hole 102 is arranged on the bottom wall 123 of the protective groove 121. The liquid inlet hole 102 penetrates the bottom wall 123 along the thickness direction of the bottom wall 123 and is connected to the protective groove 121. Specifically, the liquid inlet hole 102 is arranged on the first part 123a and penetrates the first part 123a along the thickness direction of the first part 123a. In the present embodiment, there can be multiple liquid inlet holes 102. Multiple liquid inlet holes 102 are arranged at intervals from each other. Exemplarily, there are three liquid inlet holes 102. In some other embodiments, the number of liquid inlet holes 102 can also be one, two, four or more than four, and the embodiments of the present application are not limited to this.

[0048] It is understandable that when the energy storage device 100 is injected, the electrolyte enters the protection groove 121 through the liquid inlet hole 102 of the plastic body 11 of the lower plastic 10, and then flows into the receiving cavity of the shell 110 through the multiple liquid inlet holes 102 on the bottom wall of the protection part 12. By providing multiple liquid inlet holes 102 on the bottom wall of the protection part 12, it is possible to prevent the electrolyte from flowing into the shell 110 at an excessive flow rate during injection, thereby avoiding the problem of battery cell failure caused by the electrolyte impacting the battery cell inside the energy storage device 100.

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

[0050] In this embodiment, the avoidance groove 103 is arranged around the circumference of the opening of the protection groove 121 and is connected with the protection groove 121. Specifically, the opening of the avoidance groove 103 is located on the second surface 112 of the plastic body 11. The avoidance groove 103 is recessed from the second surface 112 toward the first surface 111 to achieve communication with the protection groove 121.

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

[0052] The cover plate 20 is installed on one side in the thickness direction of the lower plastic 10. Specifically, the cover plate 20 is installed on the second surface 112 of the plastic body 11 of the lower plastic 10. Exemplarily, 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. Among them, 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 facing 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 the thickness direction of the cover plate 20 (Z-axis direction shown in the figure), and are arranged at intervals from each other. In the present embodiment, the explosion-proof hole 201 is located in the middle of the cover plate 20 body. Along the thickness direction of the end cover assembly 120, the explosion-proof hole 201 is arranged opposite to the explosion-proof fence 113 of the lower plastic 10, and is connected to the explosion-proof fence 113. The explosion-proof hole 201 can be connected to the interior of the energy storage device 100 through the explosion-proof fence 113.

[0054] The two assembly holes 203 are both located at the edge of the cover plate 20. Along the length direction of the cover plate 20 (the X-axis direction in the figure), the two assembly holes 203 are respectively located on opposite sides of the explosion-proof hole 201. Each assembly hole 203 is connected to a mounting hole 101 of the lower plastic 10 to facilitate the installation of the pole unit 60, so that the pole unit 60 is assembled with the lower plastic 10 and the cover plate 20.

[0055] The injection hole 202 is located between an assembly hole 203 and the explosion-proof hole 201, and is connected to the liquid inlet hole 102 of the lower plastic 10. The electrolyte can flow into the protection groove 121 of the protection part 12 through the injection hole 202 of the cover plate 20 and the liquid inlet hole 102 of the lower plastic 10 in sequence, and be injected into the housing 110 (such as Figure 1 The receiving chamber is provided with a receiving chamber as shown in the figure, so as to realize the perfusion of the electrolyte of the energy storage device 100.

[0056] Specifically, the injection hole 202 includes an injection portion 202a and a step portion 202b. The step portion 202b is located on the side of the injection portion 202a away from the protection groove 121 of the lower plastic 10 and is connected to the injection portion 202a. The diameter of the step portion 202b is greater than the diameter of the injection portion 202a.

[0057] In addition, the cover plate 20 is further provided with a convex ring 23. Specifically, the convex ring 23 is provided on the first surface 21 of the cover plate 20 and is provided around the injection hole 202. In this embodiment, the convex 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 convex ring 23 is flush with the hole wall surface of the injection hole 202. When the cover plate 20 is installed to the lower plastic 10, the convex ring 23 is installed in the avoidance groove 103.

[0058] Please refer to Figure 4 , Figure 8 and Fig. 9 , Figure 8 yes Figure 3 The schematic diagram of the structure of the heat shrink nail 40 in the end cover assembly 120 is shown. Fig. 9 yes Figure 4 The schematic diagram of the partial cross-sectional structure of the end cover assembly 120 after welding is shown.

[0059] The heat shrink nail 40 is passed through the injection hole 202, and is loosely matched with the injection hole 202, and extends into the protective groove 121. The length of the heat shrink nail 40 is greater than the width of the protective groove 121, and is less than or equal to the length of the protective groove 121. Exemplarily, the heat shrink nail 40 is roughly cylindrical. The heat shrink nail 40 can be made of heat shrink materials such as polypropylene (PP), polybutylece terephthalate (PBT) or polyethylene terephthalate (PVT). It should be understood that the heat shrink nail 40 is made of materials such as polypropylene, polybutylece terephthalate or polyethylene terephthalate, so that the heat shrink nail 40 can shrink after being heated. When the heat shrink nail 40 shrinks, the radial shrinkage of the heat shrink nail 40 is equal to or greater than 3%, so as to ensure that the heat shrink nail 40 can achieve clearance fit with the injection hole 202 after shrinking due to heat.

[0060] Specifically, the heat shrink nail 40 includes a sealing portion 41 and an introduction portion 42 connected to each other. Exemplarily, the sealing portion 41 and the introduction portion 42 are integrally formed. Among them, the sealing portion 41 is clearance-matched with the injection hole 202. The introduction portion 42 is connected to one end of the sealing portion 41. In this embodiment, the diameter of the end of the introduction portion 42 away from the sealing portion 41 is smaller than the aperture of the injection hole 202, so that the introduction portion 42 can smoothly pass through the injection hole 202 and extend into the protective groove 121. Among them, the diameter of the introduction portion 42 gradually decreases in the direction from the sealing portion 41 to the introduction portion 42. In addition, in this embodiment, along the length direction of the heat shrink nail 40 (Z-axis direction shown in the figure), the length of the introduction portion 42 is smaller than the length of the sealing portion 41, so as to ensure that the subsequent heat shrink nail 40 can block the liquid inlet 102 after falling into the protective groove 121.

[0061] When the heat shrink nail 40 is installed on the cover plate 20, the introduction part 42 first extends into the injection hole 202. At this time, since the diameter of the introduction part 42 gradually decreases, the introduction part 42 can guide the installation of the heat shrink nail 40, which can improve the convenience of installing the heat shrink nail 40 to the injection hole 202. In this process, since the diameter of the introduction part 42 is smaller than the aperture of the injection hole 202, when the end of the introduction part 42 close to the sealing part 41 enters the opening of the injection hole 202, the end of the sealing part 41 close to the introduction part 42 is located at the opening edge of the injection hole 202. At this time, it is necessary to use a thrust to push the sealing part 41 so that at least part of the sealing part 41 enters the injection hole 202. At this time, the sealing part 41 is interference fit with the injection hole 202 to achieve sealing of the injection hole 202. At the same time, the sealing part 41 of the heat shrink nail 40 is also penetrated on the inner side of the convex ring 23. When the sealing part 41 is installed on the cover plate 20, the convex ring 23 can limit the sealing part 41 to prevent the sealing part 41 from being offset or tilted, thereby ensuring that the sealing part 41 has a good sealing effect on the injection hole 202. In addition, since the inner surface of the convex ring 23 is flush with the hole wall surface of the injection hole 202, the convex ring 23 can also be prevented 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 on the cover plate 20. In this embodiment, after the heat shrink nail 40 and the cover plate 20 are assembled, the end of the introduction part 42 of the heat shrink nail 40 that is away from the sealing part 41 is spaced from the groove bottom wall 123 of the protective groove 121.

[0062] Please continue reading Figure 4 and Fig. 9 The sealing nail 50 is located on the side of the heat shrink nail 40 away from the bottom wall 123 of the groove, and is installed in the step portion 202b of the injection hole 202 to seal the step portion 202b of the injection hole 202. Exemplarily, the sealing nail 50 is a sealing aluminum nail. In this embodiment, during the laser welding of the sealing nail 50 and the cover plate 20, as shown in FIG. Fig. 9 As shown, the edge of the sealing pin 50 close to the cover plate 20 and the edge of the cover plate 20 close to the sealing pin 50 are melted and mixed together due to the laser energy injection, and then cooled to form a welded portion 70. It can also be understood that the end cover assembly 120 also includes a welded portion 70, and the welded portion 70 is connected between the cover plate 20 and the sealing pin 50. Specifically, the welded portion 70 is formed by welding a portion of the sealing pin 50 close to the cover plate 20 and a portion of the cover plate 20 close to the sealing pin 50.

[0063] In the manufacturing process of the energy storage device 100, after the energy storage device 100 is injected with liquid, nitrogen is filled into the energy storage device 100, and the heat shrink nail 40 is plugged to seal the injection hole 202. At this time, the heat shrink nail 40 does not shrink, and the sealing portion 41 of the heat shrink nail 40 is interference fit with the injection hole 202 to seal the injection hole 202, thereby preventing the energy storage device 100 from leaking during the subsequent production process.

[0064] Then, the sealing nail 50 is welded to the cover plate 20. Fig. 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 the heat, and the sealing portion 41 of the heat shrink nail 40 and the injection portion 202a of the injection hole 202 are changed from an interference fit setting to a clearance fit setting. That is, after the sealing nail 50 is welded to the cover plate 20, the sealing portion 41 of the heat shrink nail 40 and the injection portion 202a of the injection hole 202 have a clearance fit. At least part of the heat shrink nail 40 is located in the protective groove 121 and blocks the liquid inlet hole 102. In this embodiment, the heat shrink nail 40 is completely located in the protective groove 121. Among them, the introduction portion 42 of the heat shrink nail 40 blocks the liquid inlet hole 102.

[0065] In this embodiment, the heat shrink nail 40 becomes smaller as a whole after heat shrinkage occurs, and falls into the protective groove 121 of the protective part 12. It can be understood that the second part 123b of the groove bottom wall 123 of the protective groove 121 is tilted, which can guide the movement of the heat shrink nail 40. When the heat shrink nail 40 falls, under the guidance of the second part 123b of the groove 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 groove bottom wall 123 of the protective groove 121, and blocks multiple liquid inlet holes 102. Under this setting, the electrolyte can be prevented from entering the protective groove 121 of the lower plastic 10 due to the swaying of the energy storage device 100, thereby preventing the unstable performance of the battery cell of the energy storage device 100 caused by the instantaneous reduction of the electrolyte, which helps to ensure the good reliability of the use of the energy storage device 100. At the same time, the heat shrink nail 40 falls into the protection groove 121 of the protection part 12 after falling, which can also prevent the heat shrink nail 40 from directly falling into 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 of the sealing nail 50 and the cover plate 20, the fusion joint 70 formed between the sealing nail 50 and the cover plate 20 has a probability of generating through cracks. Since the heat shrink nail 40 shrinks due to heat during the welding process, 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, the energy storage device 100 is subjected to a helium inspection process. The heat shrink nail 40 will not block the helium inside the energy storage device 100, and the helium can overflow from the through cracks in the fusion joint 70 through the injection hole 202, so that the helium is detected by the helium detector. Under this setting, it is possible to timely detect whether there are through cracks or other leakage defects in the welding area between the sealing nail 50 and the cover plate 20 during the helium inspection process, thereby ensuring the accuracy of the welding abnormality detection between the sealing nail 50 and the cover plate 20, helping to reduce the product defect rate of the energy storage device 100, and further reducing the risk of leakage of the energy storage device 100 during subsequent use or transportation, thereby improving the safety of the energy storage device 100. At the same time, the heat shrink nail 40 in this embodiment shrinks due to the residual heat of the welding sealing nail 50 and then falls into the protective groove 121 by itself. After the sealing nail 50 and the cover plate 20 are welded, there is no need to press the sealing nail 50 to make the heat shrink nail 40 fall, thereby simplifying the production process of the energy storage device 100 and helping to improve the production efficiency of the energy storage device 100.

[0067] Please refer 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. Exemplarily, the explosion-proof valve 30 can be fixedly connected to the hole wall of the explosion-proof hole 201 by welding to be installed in the explosion-proof hole 201. It can be understood that since the explosion-proof hole 201 connects the inside and outside of the energy storage device 100, when the air pressure inside the energy storage device 100 is too high, the explosion-proof valve 30 will rupture under the action of the air pressure, and the gas inside the energy storage device 100 can be discharged to the outside of the energy storage device 100 in time through the explosion-proof fence 113 of the lower plastic 10 and the explosion-proof hole 201 of the cover plate 20 in turn, thereby avoiding the explosion of the energy storage device 100 and improving the reliability of the energy storage device 100.

[0068] In addition, the end cap assembly 120 may further include a protective sheet 80. The protective sheet 80 is mounted on the cover plate 20 and covers the explosion-proof hole 201. The protective sheet 80 is used to protect the explosion-proof valve 30 to prevent the explosion-proof valve 30 from being damaged by the external environment and external forces, thereby preventing the explosion-proof valve 30 from being accidentally touched, and ensuring the good reliability of the energy storage device 100.

[0069] Please refer to Fig.10 , Fig.11 and Fig.12 , Fig.10 yes Figure 2The end cap assembly 120 is a partial structural schematic diagram of the second embodiment after being cut along AA. Fig.11 yes Fig.10 The schematic diagram of the structure of the lower plastic 10 in the end cap assembly 120 at another angle is shown. Fig.12 yes Fig.11 The cross-sectional structure diagram of the lower plastic 10 after being cut along DD is shown.

[0070] The end cap assembly 120 shown in this embodiment is different from the end cap assembly 120 shown in the first embodiment described above in that the number of the liquid inlet hole 102 is one. The aperture of the liquid inlet hole 102 is larger than the diameter of the end of the introduction portion 42 facing the groove bottom wall 123, and smaller than the diameter of the end of the sealing portion 41 away from the introduction portion 42, so as to hold and limit the heat shrink nail 40 that falls after subsequent heat shrinkage, so as to prevent the heat shrink nail 40 from falling into the battery cell of the energy storage device 100 and affecting the normal operation of the battery cell. In addition, the aperture of the liquid inlet hole 102 gradually decreases from the opening of the protective groove 121 to the groove bottom wall 123 of the protective groove 121.

[0071] Please refer to Fig.10 and Fig.13 , Fig.13 yes Fig.10 A schematic structural diagram of the heat shrinkable nail 40 in the end cover assembly 120 is shown.

[0072] In this embodiment, the length of the introduction portion 42 of the heat shrink nail 40 is greater than the length of the sealing portion 41. Under this setting, on the one hand, the guiding function of the introduction portion 42 can be further enhanced, and the convenience of the heat shrink nail 40 entering the injection hole 202 can be improved. On the other hand, by increasing the length of the introduction portion 42, the heat shrink nail 40 can be introduced long to prevent the introduction portion 42 and the hole wall of the injection hole 202 from hanging out of the rubber thread, thereby ensuring that the subsequent sealing portion 41 of the heat shrink nail 40 can smoothly enter the injection hole 202 to seal the injection hole 202, thereby ensuring the assembly reliability between the heat shrink nail 40 and the cover plate 20.

[0073] See also Fig.10 and Fig.14 , Fig.14 yes Fig.10 The diagram is a partial structural diagram of the end cover assembly 120 after welding.

[0074] In the manufacturing process of the energy storage device 100, after the energy storage device 100 is injected with liquid, nitrogen is filled into the energy storage device 100, and the heat shrink nail 40 is plugged to seal the injection hole 202. At this time, the heat shrink nail 40 does not shrink, and the sealing portion 41 of the heat shrink nail 40 is interference fit with the injection hole 202 to seal the injection hole 202, thereby preventing the energy storage device 100 from leaking liquid in the subsequent production process.

[0075] Then, the sealing nail 50 is welded to the cover plate 20. Fig.14 As shown, when the sealing nail 50 and the cover plate 20 are laser welded, the heat generated by the laser welding is transferred to the heat shrink nail 40 through the cover plate 20. At this time, the heat shrink nail 40 shrinks due to the heat, and the sealing portion 41 of the heat shrink nail 40 and the liquid injection hole 202 are changed from an interference fit setting to a clearance fit setting. In this embodiment, the heat shrink nail 40 becomes smaller as a whole after heat shrinkage. Among them, the introduction portion 42 is penetrated through the liquid inlet hole 102 and blocks the liquid inlet hole 102.

[0076] In this embodiment, by making the aperture of the liquid inlet hole 102 larger than the diameter of the end of the introduction part 42 facing the groove bottom wall 123, and smaller than the diameter of the end of the sealing part 41 away from the introduction part 42, on the one hand, the heat shrink nail 40 can be made to fall smoothly into the liquid inlet hole 102 after being heat-shrunk, and the heat shrink nail 40 can be tilted to one side in the radial direction of the liquid inlet hole 102, which can reduce the up and down displacement space of the heat shrink nail 40, so that the heat shrink nail 40 is clamped in the protective groove 121 to achieve the blocking of the liquid inlet hole 102, thereby preventing the electrolyte from entering the protective groove 121 of the lower plastic 10 due to the sloshing of the energy storage device 100, preventing the unstable performance of the battery cell of the energy storage device 100 due to the instantaneous reduction of the electrolyte, and thus helping to ensure the good reliability of the use of the energy storage device 100. On the other hand, it can also prevent the heat shrink nail 40 from directly falling into the battery cell and affecting the normal operation of the battery cell, thereby ensuring the good reliability of the use of the energy storage device 100. In addition, as the diameter of the liquid inlet hole 102 gradually decreases, the wall surface of the liquid inlet hole 102 can also play a guiding role, making it easier for the introduction part 42 to slide into the liquid inlet hole 102, thereby achieving the blocking of the liquid inlet hole 102 by the introduction part 42.

[0077] Please refer to Fig.15 , Fig.16 and Fig.17 , Fig.15 yes Figure 2 The end cap assembly 120 is a partial structural schematic diagram of the third embodiment after being cut along AA. Fig.16 yes Fig.15 The schematic diagram of the structure of the lower plastic 10 in the end cap assembly 120 at another angle is shown. Fig.17 yes Fig.16 The cross-sectional structure diagram of the lower plastic 10 after being cut along EE is shown.

[0078] The end cap assembly 120 shown in this embodiment is different from the end cap assembly 120 shown in the second embodiment described above in that the protection portion 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 arranged 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 circumference of the liquid inlet hole 102 and are spaced apart from each other.

[0079] In this embodiment, a plurality of connecting plates 126 and baffles 125 enclose a protective groove 121. A liquid inlet hole 102 is formed between two adjacent connecting plates 126. It can also be understood that the liquid inlet hole 102 is provided on the groove side wall 124 of the protective groove 121, and penetrates the groove side wall 124 along the thickness direction of the groove side wall 124. When the energy storage device 100 is injected with liquid, the electrolyte flows into the protective groove 121 through the liquid injection hole 202 of the cover plate 20, and flows into the receiving cavity of the shell 110 from the liquid inlet hole 102 formed between two adjacent connecting plates 126, thereby realizing the injection of liquid into the energy storage device 100.

[0080] Please refer to Fig.15 and Fig.18 , Fig.18 yes Fig.15 The schematic diagram of the partial cross-sectional structure of the end cover assembly 120 after welding is shown.

[0081] In this embodiment, during the manufacturing process of the energy storage device 100, after the energy storage device 100 is injected with liquid, nitrogen is injected into the energy storage device 100, and the heat shrink nail 40 is plugged to seal the injection hole 202. At this time, the heat shrink nail 40 does not shrink, and the sealing portion 41 of the heat shrink nail 40 is interference fit with the injection hole 202 to seal the injection hole 202, thereby preventing the energy storage device 100 from leaking liquid during the subsequent production process.

[0082] Then, the sealing nail 50 is welded to the cover plate 20. Fig.18 As shown, when the sealing nail 50 is laser welded with 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 the heat, and the sealing portion 41 of the heat shrink nail 40 and the injection hole 202 are changed from an interference fit setting to a clearance fit setting. Among them, the end of the introduction portion 42 of the heat shrink nail 40 that is away from the sealing portion 41 abuts against the baffle 125 of the protective portion 12. Under this setting, it can be prevented that the heat shrink nail 40 directly falls into the battery cell and affects the normal operation of the battery cell, thereby ensuring that the energy storage device 100 has good reliability in use.

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

[0084] The above description is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application; the implementation methods and features of the implementation methods of the present application can be combined with each other without conflict. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. An end cap assembly for use in an energy storage device, characterized in that: The end cover assembly includes a lower plastic, a heat shrink nail, a cover plate and a sealing nail. The lower plastic is provided with a protective groove and a liquid inlet hole. 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 side wall and a groove bottom wall. The groove bottom wall includes a first part and a second part connected to each other. The second part is arranged around the first part and connected between the first part and the groove side wall. In the direction from the groove side wall to the first part, the distance between the second part and the opening of the protective groove gradually increases. The liquid inlet hole is arranged in the first part and penetrates the first part in the thickness direction of the first part. The cover plate is installed on one side of the lower plastic in the thickness direction, and the cover plate is provided with a liquid injection hole, which penetrates the cover plate in the thickness direction of the cover plate and is connected with the protective groove; The heat shrink nail is in gap fit with the liquid injection hole, and at least part of the heat shrink nail is located in the protective groove and blocks the liquid inlet hole; The sealing nail is located at a side of the heat shrink nail away from the bottom wall of the groove, and is installed on the liquid injection hole to seal the liquid injection hole.

2. The end cap assembly according to claim 1, characterized in that: The heat shrink nail is completely located in the protective groove, and the length of the heat shrink nail is greater than the width of the protective groove and less than or equal to the length of the protective groove.

3. The end cap assembly according to claim 1 or 2, characterized in that: The heat shrink nail includes a sealing part and an introduction part which are connected to each other. The sealing part is loosely matched with the liquid injection hole. The introduction part is connected to one end of the sealing part and blocks the liquid inlet hole. The diameter of the introduction part gradually decreases in the direction from the sealing part to the introduction part.

4. The end cap assembly according to claim 3, characterized in that: Along the thickness direction of the end cover assembly, the liquid inlet hole is arranged opposite to the liquid injection hole, and the diameter of the liquid inlet hole is larger than the diameter of the end of the introduction portion facing the bottom wall of the groove, and smaller than the diameter of the end of the sealing portion facing away from the introduction portion; The introduction portion penetrates the liquid inlet hole and blocks the liquid inlet hole.

5. The end cap assembly according to claim 4, characterized in that: The aperture of the liquid inlet hole gradually decreases in the direction from the opening of the protection groove to the bottom wall of the groove.

6. The end cap assembly according to claim 1, characterized in that: When the heat shrink nail is heat-shrunk, the radial shrinkage amount of the heat shrink nail is equal to or greater than 3%.

7. The end cap assembly according to claim 1, characterized in that: There are a plurality of liquid inlet holes, and the plurality of liquid inlet holes are arranged at intervals from each other. Along the thickness direction of the end cover assembly, the plurality of liquid inlet holes are arranged opposite to the liquid injection hole.

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

9. The end cap assembly according to claim 1, characterized in that: The injection hole includes an injection portion and a step portion, wherein the step portion is located on a side of the injection portion away from the protective groove and is connected to the injection portion, and the diameter of the step portion is greater than the diameter of the injection portion; The heat shrink nail is clearance-matched with the liquid injection portion; The sealing pin is installed on the step portion and seals the step portion.

10. An energy storage device, characterized in that: It comprises a shell, a battery cell and an end cap assembly as described in any one of claims 1 to 9, wherein the shell is provided with a receiving cavity, the receiving cavity receives the battery cell and an electrolyte, the battery cell is immersed in the electrolyte, and the end cap assembly is mounted on the shell and closes the opening of the receiving cavity.

11. An electrical device, characterized in that: It includes the energy storage device as described in claim 10, and the energy storage device supplies power to the electrical equipment.

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