End cover assembly, battery monomer and energy storage device

Abstract

The utility model provides an end cover assembly, a battery cell and an energy storage device. The end cover assembly comprises a top cover, the top cover is provided with a mounting hole, a first surface and a second surface, the first surface and the second surface are oppositely arranged, and the mounting hole penetrates through the first surface and the second surface; the pole comprises a first penetrating part and a second penetrating part, the first penetrating part penetrates through the mounting hole, the second penetrating part is convexly arranged on one side, close to the second surface, of the first penetrating part, and at least part of the second penetrating part protrudes out of one side, away from the first surface, of the top cover; and the pressing ring is arranged on the periphery of the second penetrating part in a sleeving mode, the maximum gap between the second penetrating part and the pressing ring is X, the thickness of the pressing ring is T in the arrangement direction of the first surface and the second surface, and the end cover assembly meets the condition that X is smaller than or equal to T.tan5 degrees.

Description

Technical Field

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

[0002] The end cap assembly of a battery cell consists of a terminal post and a pressure ring. After the end cap assembly is assembled, the terminal post and the pressure ring need to be laser welded to achieve an electrical connection. However, there is an assembly gap between the terminal post and the pressure ring. During laser welding, there is a high probability that the laser will pass through this assembly gap and hit the lower plastic or sealing ring of the end cap assembly, causing it to melt and produce a large amount of gas or smoke. When these gases or smoke are discharged, they will blow away the molten aluminum at the weld site, causing weld failure. Utility Model Content

[0003] A first embodiment of the present application provides an end cap assembly, comprising:

[0004] a top cover, the top cover having a mounting hole, a first surface and a second surface disposed opposite to each other, the mounting hole respectively passing through the first surface and the second surface;

[0005] a pole, the pole comprising a first penetration portion and a second penetration portion, the first penetration portion being penetrated through the mounting hole, the second penetration portion being protruded from a side of the first penetration portion close to the second surface, and the second penetration portion at least partially protruding from a side of the top cover facing away from the first surface; and

[0006] A pressure ring is sleeved on the outer circumference of the second penetration portion, the maximum gap between the second penetration portion and the pressure ring is X, and the thickness of the pressure ring along the arrangement direction of the first surface and the second surface is T, then the end cover assembly satisfies: X≤T·tan5°.

[0007] Furthermore, a maximum gap X between the second penetration portion and the pressure ring is in the range of 0.02 mm ≤ X ≤ 0.17 mm.

[0008] Furthermore, the thickness T of the pressure ring is in the range of 1 mm ≤ T ≤ 2.5 mm.

[0009] Furthermore, the second penetration portion has an outer peripheral side wall, the pressure ring has an inner peripheral side wall, the end of the outer peripheral side wall facing away from the first penetration portion and the end of the inner peripheral side wall close to the first penetration portion form an annular surface, and the angle between the annular surface and the inner peripheral side wall is α, wherein α≤5°.

[0010] Furthermore, the first penetration portion has a first step surface facing away from the first surface, and the first step surface is arranged around the periphery of the second penetration portion; the line width w1 of the first step surface is in the range of: 0.2mm≤w1≤2mm.

[0011] Furthermore, the pole further has a protruding portion, which is protruding from the surface of the second penetration portion away from the first penetration portion, and the second penetration portion has a second step surface away from the first penetration portion, and the second step surface is arranged around the outer periphery of the protruding portion.

[0012] Furthermore, the line width w2 of the second step surface is in the range of 0.3 mm ≤ w2 ≤ 1.5 mm.

[0013] Furthermore, the end cover assembly also includes an upper plastic, which is spaced apart from the pole, and the upper plastic portion is located between the first penetration portion and the top cover, for insulating the pole from the top cover, and the upper plastic portion is also partially located between the pressure ring and the top cover, for insulating the pressure ring from the top cover; along the thickness direction of the pressure ring, the pressure ring supports the upper plastic, and the pressure ring is gap-fitted with the first step surface.

[0014] Furthermore, along the thickness direction of the pressure ring, the range of the gap d between the pressure ring and the first step surface is: 0.01 mm≤d≤0.5 mm.

[0015] Furthermore, the upper plastic includes a first insulating portion, a second insulating portion and a third insulating portion that are bent and connected in sequence, and the first insulating portion and the third insulating portion are bent in opposite directions compared to the second insulating portion; the first insulating portion is located in the mounting hole and between the first penetration portion and the top cover; the second insulating portion is at least partially embedded in the side of the top cover away from the first surface, and the second insulating portion has a bearing surface facing the pressure ring, and the bearing surface is used to bear the pressure ring, and the pressure ring is in contact with the bearing surface; the third insulating portion is arranged around the outer circumference of the pressure ring; the first step surface is arranged closer to the first surface than the bearing surface.

[0016] Furthermore, the upper plastic includes a first insulating portion, a second insulating portion and a third insulating portion that are bent and connected in sequence, and the first insulating portion and the third insulating portion are bent in opposite directions compared to the second insulating portion; the first insulating portion is located in the mounting hole and between the first penetration portion and the top cover; the second insulating portion is at least partially embedded in the side of the top cover away from the first surface, and the second insulating portion has a bearing surface facing the pressure ring, and the bearing surface is used to bear the pressure ring; the third insulating portion is arranged around the outer circumference of the pressure ring; the bearing surface is flush with the first step surface or the bearing surface is arranged closer to the first surface than the first step surface, and the pressure ring has an avoidance groove on the side facing the first penetration portion and corresponding to the position of the first step surface.

[0017] A second embodiment of the present application provides a battery cell, comprising:

[0018] case;

[0019] The end cover assembly according to the first aspect of the present application, wherein the end cover assembly and the shell form a receiving cavity; and

[0020] An electrode assembly is disposed in the receiving cavity and is electrically connected to the pole of the end cap assembly.

[0021] A third embodiment of the present application provides an energy storage device, comprising:

[0022] a box body having a receiving cavity; and

[0023] A plurality of battery cells according to the second aspect of the present application are housed in the accommodating cavity.

[0024] The end cover assembly of the embodiment of the present application includes a top cover, a pole and a pressure ring. The top cover has a mounting hole, a first surface and a second surface arranged opposite to each other, and the mounting hole passes through the first surface and the second surface respectively. The pole includes a first penetration portion and a second penetration portion, the first penetration portion is penetrated by the mounting hole, the second penetration portion is protruded on the side of the first penetration portion close to the second surface, and the second penetration portion at least partially protrudes from the side of the top cover away from the first surface. The pressure ring is sleeved on the outer periphery of the second penetration portion, and the maximum gap between the second penetration portion and the pressure ring is X. Along the arrangement direction of the first surface and the second surface, the thickness of the pressure ring is T, then the end cover assembly satisfies: X≤T·tan5°. In this embodiment, the second penetration portion is protruded from the first penetration portion, and the pressure ring is sleeved on the outer periphery of the second penetration portion. In this way, when the pressure ring and the second penetration portion are laser welded, when the laser passes through the gap between the second penetration portion and the pressure ring, the laser will hit the first penetration portion instead of directly hitting the upper plastic or the sealing ring. This can better avoid the upper plastic or the sealing ring from melting or dissolving during laser welding, thereby generating gas or smoke, and further causing welding explosion points between the pole and the pressure ring, affecting the stability and reliability of the welding between the pole and the pressure ring. In addition, the end cover assembly satisfies: X≤T·tan5°, which can better prevent the laser from passing through the gap between the pressure ring and the second penetration portion during laser welding, reduce the probability of the upper plastic or sealing ring being heated and melted or melting, and generating gas or smoke, thereby better avoiding the generation of welding explosion points between the pressure ring and the pole; in addition, the generation of gas or black smoke can easily cause black carbonization marks on the surface of the pole away from the first surface, affecting the appearance of the end cover assembly and reducing the welding yield of the end cover assembly. By ensuring X≤T·tan5°, the welding yield of the end cover assembly can be better improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 It is a structural diagram of an energy storage device provided in one embodiment of the present application.

[0027] Figure 2 It is a structural schematic diagram of a battery cell provided in one embodiment of the present application.

[0028] Figure 3 The battery cell provided in one embodiment of the present application is Figure 2Schematic diagram of the cross-sectional structure in the AA direction.

[0029] Figure 4 It is a structural schematic diagram of an end cover assembly provided in one embodiment of the present application.

[0030] Figure 5 It is a schematic diagram of the exploded structure of the end cover assembly provided in one embodiment of the present application.

[0031] Figure 6 It is a schematic planar structural diagram of an end cover assembly provided in one embodiment of the present application.

[0032] Figure 7 The end cap assembly provided in one embodiment of the present application is along Figure 6 Schematic diagram of the cross-sectional structure in the middle BB direction.

[0033] Figure 8 yes Figure 7 Enlarged view of the dotted box I in the middle.

[0034] Figure 9 yes Figure 8 Enlarged view of the middle dashed box II.

[0035] Figure 10 Schematic diagram of the structure of a pole provided in one embodiment of the present application.

[0036] Figure 11 The end cap assembly of one embodiment of the present application is Figure 7 Enlarged view of the dotted box III.

[0037] Figure 12 The end cap assembly of another embodiment of the present application is Figure 7 Enlarged view of the dotted box III.

[0038] Description of reference numerals:

[0039] 300-energy storage device, 310-box, 301-accommodation cavity, 200-battery cell, 210-housing, 220-electrode assembly, 221-positive electrode sheet, 222-diaphragm, 223-negative electrode sheet, 230-accommodation cavity, 100-end cover assembly, 10-top cover, 11-mounting hole, 12-first surface, 13-second surface, 30-pole, 31-first penetration portion, 311-first step surface, 32 -Second penetration portion, 321-outer peripheral side wall, 322-second step surface, 33-protruding portion, 34-flange portion, 40-pressure ring, 41-inner peripheral side wall, 42-avoidance groove, 421-first sub-surface, 422-second sub-surface, 423-third sub-surface, 50-upper plastic, 51-first insulating portion, 52-second insulating portion, 521-bearing surface, 53-third insulating portion, 60-sealing ring, 70-lower plastic. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0041] The terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0042] The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

[0043] It should be noted that, for the convenience of explanation, in the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments.

[0044] Currently, the generation of green electricity generally relies on photovoltaics, wind power, and hydropower. However, wind and solar energy are generally intermittent and highly volatile, which can cause grid instability, insufficient electricity during peak hours, and excessive electricity during off-peak hours. Unstable voltage can also damage electricity. Therefore, insufficient electricity demand or insufficient grid capacity may lead to the problem of "wind and solar power curtailment". To solve these problems, we must rely on energy storage. This means converting electrical energy into other forms of energy through physical or chemical means and storing them. When needed, this energy is converted into electrical energy and released. Simply put, energy storage is like a large "power bank", storing electricity when photovoltaic and wind energy are sufficient and releasing the stored electricity when needed.

[0045] Taking electrochemical energy storage as an example, this solution provides an energy storage device with a chemical battery cell inside. The device mainly uses the chemical elements in the battery cell as the energy storage medium. The charging and discharging process is accompanied by chemical reactions or changes in the energy storage medium. Simply put, the electricity generated by wind and solar energy is stored in the chemical battery cell. When the use of external electricity reaches its peak, the stored electricity is released for use, or transferred to places where electricity is scarce for use.

[0046] See Figure 1 An embodiment of the present application provides an energy storage device 300 , which includes a box body 310 and a plurality of battery cells 200 . The box body 310 has a receiving cavity 301 ; the plurality of battery cells 200 are received in the receiving cavity 301 .

[0047] The energy storage device 300 of the embodiment of the present application may be, but is not limited to, at least one of an energy storage module, an energy storage cabinet, an energy storage box, an energy storage container, etc. The energy storage device 300 of the embodiment of the present application can be applied to power grids, homes, industrial applications, vehicles, etc., to store electrical energy and provide electrical energy to electrical loads when needed.

[0048] Optionally, there may be multiple accommodating cavities 301 , and each accommodating cavity 301 is used to accommodate one group of battery modules or multiple groups of battery modules.

[0049] Optionally, the battery cell 200 may be, but is not limited to, a secondary battery (rechargeable battery), a primary battery, or the like.

[0050] Optionally, the battery cell 200 may be, but is not limited to, a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery, a magnesium-ion battery, or the like.

[0051] A rechargeable battery, also known as a rechargeable battery or storage battery, is a battery that can be recharged after discharge to reactivate its active materials and allow for continued use. The recyclability of rechargeable batteries has made them an increasingly popular power source for electrical devices.

[0052] Optionally, multiple battery cells 200 may be connected in series, in parallel, or in mixed connection.

[0053] Optionally, the multiple battery cells 200 may be arranged in an array or stacked. In one embodiment, the multiple battery cells 200 are divided into multiple battery modules, each battery module comprising multiple battery cells 200, and the multiple battery cells 200 in each battery module are arranged in an array or stacked, and the multiple battery modules are arranged or stacked at intervals.

[0054] See Figures 2 to 5 The embodiment of the present application also provides a battery cell 200, which includes a shell 210, an end cover assembly 100 and an electrode assembly 220, wherein the end cover assembly 100 and the shell 210 enclose a receiving cavity 230; the electrode assembly 220 is disposed in the receiving cavity 230, and the electrode assembly 220 is electrically connected to the pole 30 of the end cover assembly 100.

[0055] It can be understood that the top cover 10 of the end cover assembly 100 is connected to the shell 210. Optionally, the top cover 10 is connected to the shell 210 by welding.

[0056] Optionally, the material of the housing 210 may be, but is not limited to, aluminum.

[0057] Optionally, the battery cell 200 may be, but is not limited to, at least one of a blade battery, a cylindrical battery, a square battery, and the like.

[0058] Optionally, the electrode assembly 220 includes a positive electrode sheet 221, a separator 222, and a negative electrode sheet 223. The separator 222 is located between the positive electrode sheet 221 and the negative electrode sheet 223 to insulate the positive electrode sheet 221 from the negative electrode sheet 223. The electrode assembly 220 may be, but is not limited to, a wound structure, a laminated structure, or the like.

[0059] Optionally, the electrode 30 may be a positive electrode 30 or a negative electrode 30. When the electrode 30 is a positive electrode 30, the positive electrode 30 is electrically connected to the positive electrode plate 221; when the electrode 30 is a negative electrode 30, the negative electrode 30 is electrically connected to the negative electrode plate 223.

[0060] Optionally, the end cap assembly 100 includes a positive electrode column 30 and a negative electrode column 30 , and the positive electrode column 30 is insulated from the negative electrode column 30 .

[0061] Optionally, the battery cell 200 further includes an electrolyte, and the electrolyte is disposed in the receiving cavity 230 .

[0062] Optionally, the electrolyte includes an electrolyte salt and an organic solvent. The electrolyte salt may be, but is not limited to, at least one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(oxalatoborate) (LiBOB), lithium difluorodioxalatophosphate (LiODFP), lithium difluorooxalatoborate (LiODFB), lithium difluorophosphate (LiPO2F2), lithium trifluoromethanesulfonate (CF3SO3Li), and the like.

[0063] In the prior art, the end cap assembly of a battery cell includes a terminal post and a pressure ring. After the end cap assembly is assembled, the terminal post and the pressure ring need to be laser welded to electrically connect the terminal post and the pressure ring. However, there is an assembly gap between the terminal post and the pressure ring. The inventors have discovered that during laser welding, there is a high probability that the laser will pass through this assembly gap and hit the lower plastic or sealing ring of the end cap assembly, causing it to melt and generate a large amount of gas or smoke. When these gases or smoke are discharged, they will blow away the molten aluminum at the weld site, causing weld hot spots.

[0064] See Figures 4 to 9 , an embodiment of the present application provides an end cap assembly 100, which includes a top cap 10, a pole 30 and a pressure ring 40. The top cap 10 has a mounting hole 11, a first surface 12 and a second surface 13 arranged opposite to each other, and the mounting hole 11 passes through the first surface 12 and the second surface 13 respectively. The pole 30 includes a first penetration portion 31 and a second penetration portion 32, the first penetration portion 31 is penetrated by the mounting hole 11, and the second penetration portion 32 is protruded on the side of the first penetration portion 31 close to the second surface 13, and the second penetration portion 32 at least partially protrudes from the side of the top cap 10 away from the first surface 12. The pressure ring 40 is sleeved on the outer periphery of the second penetration portion 32, and the maximum gap between the second penetration portion 32 and the pressure ring 40 is X. Along the arrangement direction of the first surface 12 and the second surface 13, the thickness of the pressure ring 40 is T, then the end cap assembly 100 satisfies: X≤T·tan5°.

[0065] Please see again Figure 5 and Figure 8 Optionally, the end cap assembly 100 further includes an upper plastic member 50 and a sealing ring 60. The upper plastic member 50 is positioned between the top cap 10 and the pressure ring 40 and between the top cap 10 and the pole 30, and is used to insulate the top cap 10 from the pole 30 and the pressure ring 40. The sealing ring 60 is at least partially positioned between the top cap 10 and the pole 30, and is used to seal the gap between the top cap 10 and the pole 30. It is understood that the sealing ring 60 is disposed around the outer circumference of the first penetration portion 31 and is at least partially disposed within the mounting hole 11. The sealing ring 60 is closer to the first surface 12 than the upper plastic member 50.

[0066] It should be noted that, when the electrode 30 is a positive electrode 30 , the pressure ring 40 is a positive electrode pressure ring 40 ; when the electrode 30 is a negative electrode 30 , the pressure ring 40 is a negative electrode pressure ring 40 .

[0067] It should be noted that when the end cap assembly 100 is assembled with the battery cell 200, the first surface 12 is closer to the interior of the battery cell 200 than the second surface 13. In other words, the second surface 13 is closer to the exterior of the battery cell 200 than the first surface 12. In some embodiments, the second surface 13 serves as part of the exterior surface of the battery cell 200.

[0068] Optionally, the first surface 12 and the second surface 13 are arranged along the thickness direction of the top cover 10 .

[0069] It can be understood that the first penetration portion 31 and the second penetration portion 32 are arranged along the arrangement direction of the first surface 12 and the second surface 13. That is, the first penetration portion 31 and the second penetration portion 32 are arranged along the thickness direction of the end cover assembly 100.

[0070] It is understood that the second penetration portion 32 at least partially protrudes from the second surface 13. It is also understood that the first penetration portion 31 and the second penetration portion 32 form a step or staircase. It is also understood that along the radial direction of the pole 30, the first penetration portion 31 protrudes from the second penetration portion 32. In other words, along a direction perpendicular to the arrangement direction of the first penetration portion 31 and the second penetration portion 32, the outer periphery of the first penetration portion 31 is larger than the outer periphery of the second penetration portion 32.

[0071] It can be understood that the pressure ring 40 is located on the side of the top cover 10 away from the first surface 12 ; in other words, the pressure ring 40 is located on the side of the top cover 10 close to the second surface 13 .

[0072] It can also be understood that the second penetration portion 32 is penetrated by the pressure ring 40 .

[0073] Optionally, the material of the top cover 10 may be, but is not limited to, aluminum, such as a plain aluminum sheet.

[0074] Optionally, the pole 30 and the pressure ring 40 are both made of metal (eg, aluminum). The pole 30 and the pressure ring 40 are welded together to electrically connect the pole 30 and the pressure ring 40. Furthermore, the second penetration portion 32 is connected to the pressure ring 40 by welding.

[0075] Please see again Figure 9 Optionally, the second penetration portion 32 has an outer peripheral sidewall 321, the pressure ring 40 has an inner peripheral sidewall 41, and the maximum gap between the inner peripheral sidewall 41 and the outer peripheral sidewall 321 is X. In other words, when the second penetration portion 32 abuts the inner peripheral sidewall 41 of the pressure ring 40, the maximum gap between the side of the second penetration portion 32 facing away from the abutting position and the pressure ring 40 is X.

[0076] Optionally, the maximum gap X between the second penetration portion 32 and the pressure ring 40 may be, but is not limited to, less than or equal to T·tan5°, less than or equal to 0.085T, less than or equal to 0.08T, less than or equal to 0.07T, less than or equal to 0.06T, less than or equal to 0.05T, less than or equal to 0.04T, etc. If the maximum gap X between the second penetration portion 32 and the pressure ring 40 is too large, when the second penetration portion 32 and the pressure ring 40 are laser welded, the laser may easily pass through the gap between the pressure ring 40 and the second penetration portion 32, thereby melting the upper plastic 50 or the sealing ring 60 of the end cap assembly 100 and generating gas or black smoke. The gas or black smoke may blow away the molten aluminum, thereby causing a welding explosion point between the second penetration portion 32 and the pressure ring 40, affecting the stability and reliability of the connection between the pole 30 and the pressure ring 40.

[0077] The end cap assembly 100 of the embodiment of the present application includes a top cap 10, a pole 30, and a pressure ring 40. The top cap 10 has a mounting hole 11, a first surface 12, and a second surface 13 disposed opposite to each other. The mounting hole 11 passes through the first surface 12 and the second surface 13 respectively. The pole 30 includes a first penetration portion 31 and a second penetration portion 32. The first penetration portion 31 is penetrated by the mounting hole 11, and the second penetration portion 32 is protruded on the side of the first penetration portion 31 close to the second surface 13, and the second penetration portion 32 at least partially protrudes from the side of the top cap 10 away from the first surface 12. The pressure ring 40 is sleeved on the outer periphery of the second penetration portion 32. The maximum gap between the second penetration portion 32 and the pressure ring 40 is X. The thickness of the pressure ring 40 along the arrangement direction of the first surface 12 and the second surface 13 is T. Then, the end cap assembly 100 satisfies: X≤T·tan5°. In this embodiment, the second penetration portion 32 is protruded from the first penetration portion 31, and the pressure ring 40 is sleeved on the outer periphery of the second penetration portion 32. In this way, when the pressure ring 40 and the second penetration portion 32 are laser welded, when the laser passes through the gap between the second penetration portion 32 and the pressure ring 40, the laser will hit the first penetration portion 31, and will not directly hit the upper plastic 50 or the sealing ring 60, thereby better avoiding the melting or dissolution of the upper plastic 50 or the sealing ring 60 during laser welding, thereby generating gas or smoke, and further causing welding explosion points between the pole 30 and the pressure ring 40, affecting the stability and reliability of the welding between the pole 30 and the pressure ring 40. In addition, the end cover assembly 100 satisfies: X≤T·tan5°, which can better prevent the laser from passing through the gap between the pressure ring 40 and the second penetration portion 32 during laser welding, and reduce the probability of the upper plastic 50 or the sealing ring 60 being heated and melted or melted to generate gas or smoke, thereby better avoiding the generation of welding explosion points between the pressure ring 40 and the pole 30; in addition, the generation of gas or black smoke can easily cause black carbonization marks on the surface of the pole 30 away from the first surface 12, affecting the appearance of the end cover assembly 100 and reducing the welding yield of the end cover assembly 100. By ensuring X≤T·tan5°, the welding yield of the end cover assembly 100 can be better improved.

[0078] In some embodiments, the maximum gap X between the second penetration portion 32 and the pressure ring 40 is in the range of 0.02 mm ≤ X ≤ 0.17 mm.

[0079] It is understood that the maximum gap X between the inner peripheral sidewall 41 and the outer peripheral sidewall 321 is in the range of 0.02 mm ≤ X ≤ 0.17 mm. It is also understood that, along the arrangement direction perpendicular to the first surface 12 and the second surface 13, the maximum gap X between the second penetration portion 32 and the pressure ring 40 is in the range of 0.02 mm ≤ X ≤ 0.17 mm.

[0080] Specifically, the maximum gap X between the second penetration portion 32 and the pressure ring 40 may be, but is not limited to, 0.02 mm, 0.04 mm, 0.06 mm, 0.08 mm, 0.10 mm, 0.12 mm, 0.14 mm, 0.16 mm, 0.17 mm, etc.

[0081] In this embodiment, if the maximum gap X between the second penetration portion 32 and the pressure ring 40 is too small, the pressure ring 40 may not be assembled when the pole 30 and the pressure ring 40 are assembled; if the maximum gap X between the second penetration portion 32 and the pressure ring 40 is too large, the laser may easily pass through the gap between the pressure ring 40 and the second penetration portion 32 when the second penetration portion 32 and the pressure ring 40 are laser welded, thereby causing the upper plastic 50 or the sealing ring 60 of the end cover assembly 100 to melt and generate gas or black smoke. The gas or black smoke may blow away the molten aluminum liquid, thereby causing welding defects such as welding explosion points or holes between the second penetration portion 32 and the pressure ring 40, affecting the stability and reliability of the connection between the pole 30 and the pressure ring 40; in addition, the generation of gas or black smoke may easily cause black carbonization marks to appear on the surface of the pole 30 away from the first surface 12, affecting the appearance of the end cover assembly 100 and reducing the welding yield of the end cover assembly 100. When the maximum gap X between the second penetration portion 32 and the pressure ring 40 is in the range of 0.02mm≤X≤0.17mm, the pole 30 and the pressure ring 40 can be easier to assemble, and welding hot spots are less likely to occur when the pole 30 and the pressure ring 40 are laser welded, thereby improving the reliability and stability of the connection between the pole 30 and the pressure ring 40, and improving the appearance yield of the pole 30 and the pressure ring 40 after welding.

[0082] Furthermore, the maximum gap X between the second penetration portion 32 and the pressure ring 40 is in the range of 0.06 mm ≤ X ≤ 0.13 mm. This makes it easier to assemble the pole 30 and the pressure ring 40, and during laser welding of the pole 30 and the pressure ring 40, the probability of the laser penetrating the gap between the pole 30 and the pressure ring 40 is reduced, thereby reducing the occurrence of welding hot spots, improving the reliability and stability of the connection between the pole 30 and the pressure ring 40, and improving the appearance yield rate of the welded pole 30 and the pressure ring 40.

[0083] In some embodiments, the thickness T of the pressure ring 40 is in the range of 1 mm ≤ T ≤ 2.5 mm.

[0084] It is understood that the thickness T of the pressure ring 40 in the arrangement direction of the first surface 12 and the second surface 13 is in the range of 1mm≤T≤2.5mm. It is also understood that the thickness T of the pressure ring 40 in the thickness direction of the end cap assembly 100 is in the range of 1mm≤T≤2.5mm.

[0085] Specifically, the thickness T of the pressure ring 40 may be, but is not limited to, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.2 mm, 2.4 mm, 2.5 mm, etc.

[0086] In this embodiment, if the thickness T of the pressure ring 40 is too thin, the penetration depth of the pressure ring 40 during welding of the electrode 30 and the pressure ring 40 is too small, resulting in reduced weld strength between the electrode 30 and the pressure ring 40, and reduced reliability and stability of the connection between the electrode 30 and the pressure ring 40. If the thickness T of the pressure ring 40 is too large, the cost of the pressure ring 40 is increased. When the thickness T of the pressure ring 40 is within the range of 1 mm ≤ T ≤ 2.5 mm, the weld strength between the electrode 30 and the pressure ring 40 is higher, and the cost of the end cap assembly 100 is lower.

[0087] Please see again Figure 9 In some embodiments, the second penetration portion 32 has an outer peripheral side wall 321, and the pressure ring 40 has an inner peripheral side wall 41. The end of the outer peripheral side wall 321 away from the first penetration portion 31 and the end of the inner peripheral side wall 41 close to the first penetration portion 31 form an annular surface, and the angle between the annular surface and the inner peripheral side wall 41 is α, where α≤5°.

[0088] Optionally, the angle α between the annular surface and the inner peripheral side wall 41 ranges from 0° to 5°.

[0089] It should be noted that the annular surface of this embodiment is a surface fitted based on the end of the outer side wall 321 away from the first penetration portion 31 and the end of the inner side wall 41 close to the first penetration portion 31. It is a virtual surface, not a solid surface.

[0090] It should be noted that when the pressure ring 40 is assembled on the second penetration portion 32, the second penetration portion 32 and the pressure ring 40 are not necessarily coaxial, and there is usually some deviation. Therefore, the values ​​of the angle α between different positions of the annular surface and the inner circumferential side wall 41 are different. The position where the gap between the second penetration portion 32 and the pressure ring 40 is smaller is smaller, and the position where the gap between the second penetration portion 32 and the pressure ring 40 is larger is larger. However, the angle between any position on the annular surface and the inner circumferential side wall 41 is less than or equal to 5°.

[0091] Specifically, the angle α between the annular surface and the inner peripheral side wall 41 may be, but is not limited to, 0°, 1°, 2°, 3°, 4°, 5°, 6°, etc.

[0092] In this embodiment, if the angle α between the annular surface and the inner circumferential side wall 41 is too large, when the second penetration portion 32 and the pressure ring 40 are laser welded, the laser can easily pass through the gap between the pressure ring 40 and the second penetration portion 32 and hit the step of the second penetration portion 32, causing the second penetration portion 32 to melt and melt the upper plastic 50 or the sealing ring 60 of the end cover assembly 100. The melting and combustion of the upper plastic 50 or the sealing ring 60 can easily produce gas or black smoke, which may blow away the molten aluminum liquid, thereby causing welding defects such as welding explosion points or holes between the second penetration portion 32 and the pressure ring 40, affecting the stability and reliability of the connection between the pole 30 and the pressure ring 40; in addition, the generation of gas or black smoke can easily cause black carbonization marks to appear on the surface of the pole 30 away from the first surface 12, affecting the appearance of the end cover assembly 100 and reducing the welding yield of the end cover assembly 100.

[0093] Please see again Figure 9 In some embodiments, the first penetration portion 31 has a first step surface 311 facing away from the first surface 12, and the first step surface 311 is arranged around the periphery of the second penetration portion 32; the line width w1 of the first step surface 311 is in the range of: 0.2mm≤w1≤2mm.

[0094] It can be understood that along the direction perpendicular to the arrangement direction of the first penetration portion 31 and the second penetration portion 32, the part of the first penetration portion 31 protruding from the second penetration portion 32 forms a step or ladder, and the surface of the step facing the second penetration portion 32 is the first step surface 311.

[0095] It should be noted that the term "line width" in this application refers to the width of a single side of the annular structure along the radial direction of the annular structure.

[0096] It should be noted that the first step surface 311 is connected to the outer peripheral side wall 321 of the second penetration portion 32 by bending.

[0097] It can be understood that the first step surface 311 is an annular structure.

[0098] It can be understood that, along a direction perpendicular to the arrangement of the first and second penetration portions 31, 32, the width w1 of the first penetration portion 31 protruding from the second penetration portion 32 is in the range of 0.2 mm ≤ w1 ≤ 2 mm. In other words, along a direction perpendicular to the arrangement of the first and second penetration portions 31, 32, the outer periphery of the first penetration portion 31 extends outward from the outer periphery of the second penetration portion 32 by a dimension w1 in the range of 0.2 mm ≤ w1 ≤ 2 mm.

[0099] Specifically, the line width w1 of the first step surface 311 may be, but is not limited to, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm, etc.

[0100] In this embodiment, by providing the first step surface 311, when the pressure ring 40 and the second penetration portion 32 are laser welded, when the laser passes through the gap between the second penetration portion 32 and the pressure ring 40, the laser will hit the first penetration portion 31, and will not directly hit the upper plastic 50 or the sealing ring 60, thereby better avoiding the melting or dissolving of the upper plastic 50 or the sealing ring 60 during laser welding, thereby generating gas or smoke, and further causing welding explosion points in the welding between the pole 30 and the pressure ring 40, affecting the stability and reliability of the welding between the pole 30 and the pressure ring 40. When the line width w1 of the first step surface 311 is too small, it cannot prevent the laser from passing through. When the laser passes through the gap between the pressure ring 40 and the second penetration portion 32, it is easy to hit the upper plastic 50 or the sealing ring 60, which can easily cause the welding between the pole 30 and the pressure ring 40 to have a welding hot spot, affecting the stability and reliability of the welding between the pole 30 and the pressure ring 40; when the line width w1 of the first step surface 311 is too large, after the pole 30 and the pressure ring 40 are welded, the pressure ring 40 will press against the upper plastic 50 of the end cover assembly 100, thereby squeezing the upper plastic The glue 50 and the sealing ring 60, the upper plastic 50 and the sealing ring 60 have a certain compressibility, therefore, the pressure ring 40 will have a certain displacement, when the line width w1 of the first step surface 311 is too large, the upper plastic 50 and the sealing ring 60 also need to be made larger, which will make the force arm of the weld mark (or welding part) between the pressure ring 40 and the second penetration part 32 too long, and the torque is too large, so that the pressure ring 40 is prone to warping, affecting the stability and reliability of the connection between the pressure ring 40 and the pole 30; in addition, the pole 30 needs to be made larger, which increases the preparation cost of the end cover assembly 100. Therefore, when the line width w1 of the first step surface 311 is in the range of 0.2mm≤w1≤2mm, it can better prevent the occurrence of welding explosion points during welding between the pressure ring 40 and the pole 30, and better improve the stability and reliability of the welding between the pressure ring 40 and the pole 30; it can also make the weld mark have a lower force arm and torque, and the pressure ring 40 is not easy to warp, which better improves the stability and reliability of the welding between the pressure ring 40 and the pole 30.

[0101] Furthermore, the line width w1 of the first step surface 311 is in the range of 0.2 mm ≤ w1 ≤ 1 mm. This can better prevent weld cracks when welding the pressure ring 40 to the terminal 30, thereby improving the stability and reliability of the welding between the pressure ring 40 and the terminal 30. It can also ensure that the weld mark has a lower moment arm and torque, making the pressure ring 40 less likely to warp, thereby improving the stability and reliability of the welding between the pressure ring 40 and the terminal 30.

[0102] Furthermore, the line width w1 of the first step surface 311 is in the range of 0.3 mm ≤ w1 ≤ 0.7 mm. This can better prevent weld cracks when welding the pressure ring 40 to the terminal 30, further improving the stability and reliability of the welding between the pressure ring 40 and the terminal 30. It can also reduce the moment arm and torque of the weld mark, making the pressure ring 40 less likely to warp, and further improving the stability and reliability of the welding between the pressure ring 40 and the terminal 30.

[0103] Please also see Figures 8 to 10 In some embodiments, the pole 30 further has a protrusion 33, which is protruded from the surface of the second penetration portion 32 away from the first penetration portion 31, and the second penetration portion 32 has a second step surface 322 away from the first penetration portion 31, and the second step surface 322 is arranged around the periphery of the protrusion 33.

[0104] It can be understood that the first penetration portion 31 , the second penetration portion 32 and the protruding portion 33 are sequentially arranged along the arrangement direction of the first surface 12 and the second surface 13 .

[0105] It can be understood that, in the direction perpendicular to the arrangement direction of the first penetration portion 31, the second penetration portion 32 and the protrusion 33, the part of the second penetration portion 32 protruding from the protrusion 33 forms a step or ladder, and the surface of the step facing the protrusion 33 is the second step surface 322.

[0106] It should be noted that the second stepped surface 322 is bent and connected to the outer peripheral side wall 321 of the second penetration portion 32. It should also be noted that the first stepped surface 311 and the second stepped surface 322 are bent in opposite directions relative to the outer peripheral side wall 321.

[0107] It can be understood that the second step surface 322 is an annular structure.

[0108] When the pole 30 is welded to the pressure ring 40, the second step surface 322 of the second penetration portion 32 is welded to the surface of the pressure ring 40 facing away from the first penetration portion 31. By setting the second step surface 322, the second step surface 322 is made lower than the surface of the protrusion 33 facing away from the second penetration portion 32. This can better prevent the weld mark between the second penetration portion 32 and the pressure ring 40 from exceeding the surface of the protrusion 33 facing away from the second penetration portion 32 (that is, the upper surface of the pole 30, or the appearance surface of the pole 30). When the end cover assembly 100 is applied to the battery cell 200, the pole 30 and the pressure ring 40 are exposed on the battery cell 200, and different battery cells 200 are electrically connected through electrical connectors (such as aluminum tabs) (that is, the poles 30 of different battery cells 200 are electrically connected through electrical connectors). If the weld mark between the pole 30 and the pressure ring 40 exceeds the upper surface of the pole 30, then when multiple battery cells 200 are electrically connected through the electrical connector, the weld mark will easily lift the electrical connector, causing poor contact between the electrical connector and the upper surface of the pole 30 (that is, the surface of the protrusion 33 away from the second penetration portion 32), thereby easily causing cold welding when the electrical connector and the protrusion 33 are welded, affecting the overcurrent of the battery cell 200.

[0109] Please see again Figure 9 In some embodiments, the line width w2 of the second step surface 322 is in the range of 0.3 mm ≤ w2 ≤ 1.5 mm.

[0110] It can be understood that, along a direction perpendicular to the arrangement of the first penetration portion 31, the second penetration portion 32, and the protruding portion 33, the width w2 of the second penetration portion 32 protruding from the protruding portion 33 is in the range of 0.2 mm ≤ w2 ≤ 2 mm. In other words, along a direction perpendicular to the arrangement of the first penetration portion 31, the second penetration portion 32, and the protruding portion 33, the dimension w2 of the outer periphery of the second penetration portion 32 extending outward from the outer periphery of the protruding portion 33 is in the range of 0.2 mm ≤ w2 ≤ 2 mm.

[0111] Specifically, the line width w2 of the second step surface 322 may be, but is not limited to, 0.3 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.5 mm, etc.

[0112] In this embodiment, if the line width w2 of the second step surface 322 is too small, the difficulty of manufacturing the second step surface 322 is increased. When the second step surface 322 is prepared, aluminum wires are likely to exist. When the end cover assembly 100 is assembled on the battery cell 200, the aluminum wires are likely to fall into the interior of the battery cell 200, which may cause a short circuit in the battery cell 200. If the line width w2 of the second step surface 322 is too large, the second penetration portion 32 and the pressure ring 40 cannot be welded to the side wall of the pole 30 (i.e., the side wall of the protrusion 33) during laser welding, so that the weld mark is not coaxial or concentric with the pole 30, which easily causes poor appearance and reduces the appearance yield of the end cover assembly 100. When the line width w2 of the second step surface 322 is in the range of: 0.3mm≤w2≤1.5mm, the second step surface 322 can be made easier to prepare, less likely to have aluminum wires, and the probability of short circuit in the battery cell 200 using the end cover assembly 100 is reduced; and when the pole 30 and the pressure ring 40 are laser welded, the poor appearance caused by the non-concentricity of the pole 30 and the weld mark can be better avoided.

[0113] Furthermore, the line width w2 of the second stepped surface 322 is in the range of 0.4 mm ≤ w2 ≤ 0.6 mm. This makes the second stepped surface 322 easier to manufacture and less likely to contain aluminum wire, thereby reducing the probability of short circuits in the battery cell 200 using the end cap assembly 100. Furthermore, during laser welding of the terminal post 30 and the pressure ring 40, poor appearance caused by misalignment between the terminal post 30 and the weld mark can be avoided.

[0114] Please also see Figure 5 、 Figure 8 and Figure 9 In some embodiments, the end cover assembly 100 further includes an upper plastic 50, which is arranged around the outer periphery of the pole 30 and the pressure ring 40, and the upper plastic 50 is spaced apart from the pole 30, for insulating the pole 30 from the top cover 10 and for insulating the pressure ring 40 from the top cover 10.

[0115] It can be understood that there is a gap between the upper plastic 50 and the pole 30 , and the upper plastic 50 does not contact the pole 30 .

[0116] Optionally, the upper plastic 50 is partially located between the first penetration portion 31 and the top cover 10, and is also partially located between the pressure ring 40 and the top cover 10. In other words, the upper plastic 50 is partially arranged around the outer circumference of the first penetration portion 31 and partially arranged around the outer circumference of the pressure ring 40.

[0117] Optionally, the upper plastic 50 is made of resin.

[0118] In this embodiment, the upper plastic 50 is spaced apart from the pole 30, so that when the pressure ring 40 is laser welded to the pole 30, part of the laser passes through the gap between the second penetration portion 32 and the pressure ring 40 and hits the first step surface 311 of the first penetration portion 31. When the first step surface 311 is melted, due to the gap between the upper plastic 50 and the pole 30, the temperature on the first penetration portion 31 is not easily transferred to the upper plastic 50, thereby better preventing the upper plastic 50 from being melted, thereby generating gas or smoke, and reducing the welding explosion point of the pole 30 and the pressure ring 40.

[0119] Please see again Figure 9 Optionally, along the thickness direction of the pressure ring 40 , the pressure ring 40 abuts against the upper plastic 50 , and the pressure ring 40 is clearance-fitted with the first step surface 311 .

[0120] It can be understood that a portion of the orthographic projection of the pressure ring 40 on the first surface 12 covers the orthographic projection of the first step surface 311 on the first surface 12 , and another portion of the orthographic projection of the pressure ring 40 on the first surface 12 covers the orthographic projection of the upper plastic 50 on the first surface 12 .

[0121] It can be understood that along the arrangement direction of the first surface 12 and the second surface 13, the pressure ring 40 is clearance-fitted with the first penetration portion 31. In other words, along the arrangement direction of the first surface 12 and the second surface 13, there is a gap between the pressure ring 40 and the first step surface 311.

[0122] When there is no gap between the pressure ring 40 and the first step surface 311 (that is, the pressure ring 40 and the first step surface 311 are in contact with each other), after the pressure ring 40 is sleeved on the second penetration portion 32 of the pole 30, before laser welding is performed, the welding tool will contact the pressure ring 40 to prevent the pressure ring 40 from moving. At this time, if there is no gap between the pressure ring 40 and the first step surface 311, the pressure ring 40 and the first step surface 311 will interfere with each other, thereby deforming the pressure ring 40, affecting the stability of the compression amount of the upper plastic 50 and the sealing ring 60, resulting in different compression amounts of the upper plastic 50 and the sealing ring 60 of different end cover assemblies 100, thereby reducing the dimensional stability of the end cover assembly 100.

[0123] Please see again Figure 9 In some embodiments, along the thickness direction of the pressure ring 40 , the range of the gap d between the pressure ring 40 and the first step surface 311 is: 0.01 mm≤d≤0.5 mm.

[0124] It can be understood that, along the arrangement direction of the first surface 12 and the second surface 13 , the range of the gap d between the pressure ring 40 and the first step surface 311 is: 0.01 mm≤d≤0.5 mm.

[0125] Specifically, the gap d between the pressure ring 40 and the first step surface 311 can be, but is not limited to, 0.01 mm, 0.03 mm, 0.05 mm, 0.08 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, etc.

[0126] In this embodiment, the gap d between the pressure ring 40 and the first step surface 311 is too small. After the pressure ring 40 is sleeved on the second penetration portion 32 of the pole 30, before laser welding, the welding tool will support the pressure ring 40 to prevent the pressure ring 40 from moving. At this time, if the gap between the pressure ring 40 and the first step surface 311 is too small, the pressure ring 40 and the first step surface 311 will interfere with each other, thereby causing the pressure ring 40 to deform, affecting the stability of the compression amount of the upper plastic 50 and the sealing ring 60, resulting in different compression amounts of the upper plastic 50 and the sealing ring 60 of different end cover assemblies 100, thereby reducing the dimensional stability of the end cover assembly 100. If the gap d between the pressure ring 40 and the first stepped surface 311 is too large, when the laser passes through the gap between the pressure ring 40 and the second penetration portion 32 and strikes the first stepped surface 311 during welding, the laser light is easily reflected by the first stepped surface 311 onto the upper plastic 50, causing the upper plastic 50 to melt and failing to prevent weld flash points. Furthermore, if the gap d between the pressure ring 40 and the first stepped surface 311 is too large, metal particles generated by welding are easily trapped inside the battery cell 200 when the end cap assembly 100 is assembled with the battery cell 200, increasing the risk of short circuiting the battery cell 200. When the gap d between the pressure ring 40 and the first stepped surface 311 is within the range of 0.01 mm ≤ d ≤ 0.5 mm, the upper plastic 50 and the sealing ring 60 of different end cap assemblies 100 can be compressed more consistently, while effectively preventing weld flash points and reducing the risk of short circuiting the battery cell 200.

[0127] Please also see Figure 5 、 Figure 9 and Figure 11In some embodiments, the upper plastic 50 includes a first insulating portion 51, a second insulating portion 52, and a third insulating portion 53 that are bent and connected in sequence, and the first insulating portion 51 and the third insulating portion 53 are bent in opposite directions compared to the second insulating portion 52; the first insulating portion 51 is located in the mounting hole 11 and between the first penetration portion 31 and the top cover 10; the second insulating portion 52 is at least partially embedded in the side of the top cover 10 away from the first surface 12, and the second insulating portion 52 has a bearing surface 521 facing the pressure ring 40, and the bearing surface 521 is used to bear the pressure ring 40, and the pressure ring 40 is in contact with the bearing surface 521; the third insulating portion 53 is arranged around the outer circumference of the pressure ring 40; the first step surface 311 is arranged closer to the first surface 12 than the bearing surface 521, so that the pressure ring 40 and the first step surface 311 are clearance-fitted.

[0128] It can be understood that the first insulating portion 51 is disposed around the outer circumference of the first penetration portion 31 , and the first insulating portion 51 and the first penetration portion 31 are spaced apart.

[0129] It can be understood that the pressure ring 40 partially covers the first step surface 311 and partially covers the bearing surface 521 of the second insulating portion 52 .

[0130] It can be understood that the first stepped surface 311 is disposed further away from the second surface 13 than the bearing surface 521. In other words, the first stepped surface 311 is disposed further away from the pressure ring 40 than the bearing surface 521, so that the pressure ring 40 is supported on the bearing surface 521, and the pressure ring 40 and the first stepped surface 311 are in clearance fit.

[0131] Optionally, in this embodiment, the surface of the pressure ring 40 facing the second insulating portion 52 may be a plane.

[0132] Optionally, the first insulating part 51, the second insulating part 52 and the third insulating part 53 are an integral structure, the first insulating part 51, the second insulating part 52 and the third insulating part 53 are different parts of the same component, and the first insulating part 51, the second insulating part 52 and the third insulating part 53 can be prepared by integral injection molding.

[0133] In this embodiment, the upper plastic 50 includes a first insulating portion 51, a second insulating portion 52 and a third insulating portion 53 which are bent and connected in sequence. The first insulating portion 51 and the third insulating portion 53 are bent in opposite directions compared to the second insulating portion 52; the first insulating portion 51 is located in the mounting hole 11 and between the first penetration portion 31 and the top cover 10; the second insulating portion 52 is at least partially embedded in the side of the top cover 10 away from the first surface 12, and the second insulating portion 52 is used to support the pressure ring 40. The second insulating portion 52 has a bearing surface 521 facing the pressure ring 40; the third insulating portion 53 is arranged around the outer periphery of the pressure ring 40; this can better insulate the top cover 10 from the pole 30, and the top cover 10 from the pressure ring 40. In addition, it can better ensure the compression amount of the lower plastic and the sealing ring 60, thereby having better sealing performance. In addition, the first step surface 311 is arranged closer to the first surface 12 than the bearing surface 521, so that the gap between the pressure ring 40 and the first step surface 311 is matched. In this way, during assembly, before laser welding, when the welding tool supports the pressure ring 40, it can better prevent the pressure ring 40 from interfering with the first step surface 311, thereby better avoiding deformation of the surface pressure ring 40, making the compression amount of the upper plastic 50 and the sealing ring 60 more stable, and the compression amount of the upper plastic 50 and the sealing ring 60 of different end cover assemblies 100 more consistent.

[0134] Please see again Figure 12 In other embodiments, the upper plastic 50 includes a first insulating portion 51, a second insulating portion 52, and a third insulating portion 53 that are bent in sequence. The first insulating portion 51 and the third insulating portion 53 are bent in opposite directions relative to the second insulating portion 52. The first insulating portion 51 is located in the mounting hole 11 and between the first through-hole 31 and the top cover 10. The second insulating portion 52 is at least partially embedded in the side of the top cover 10 away from the first surface 12. The second insulating portion 52 has a facing The bearing surface 521 of the pressure ring 40 is used to bear the pressure ring 40; the third insulating portion 53 is arranged around the outer periphery of the pressure ring 40; the bearing surface 521 is flush with the first step surface 311 or the bearing surface 521 is arranged closer to the first surface 12 than the first step surface 311, and the pressure ring 40 faces the side of the first penetration portion 31 and has an avoidance groove 42 corresponding to the position of the first step surface 311, so that the pressure ring 40 and the first step surface 311 are clearance-fitted.

[0135] It can be understood that the bearing surface 521 is flush with the first step surface 311 or the bearing surface 521 is arranged farther away from the second surface 13 than the first step surface 311 .

[0136] It can be understood that the surface of the pressure ring 40 facing the first penetration portion 31 and the second insulating portion 52 includes a first sub-surface 421, a second sub-surface 422 and a third sub-surface 423 which are bent and connected in sequence, and the first sub-surface 421 and the third sub-surface 423 are bent in opposite directions compared to the second sub-surface 422, and the first sub-surface 421 is bent and connected to the inner circumferential side wall 41, and the first sub-surface 421 and the second sub-surface 422 enclose the avoidance groove 42, and the first sub-surface 421 is gap-fitted with the first step surface 311, and the third sub-surface 423 abuts the bearing surface 521.

[0137] In one embodiment, the first sub-surface 421 is parallel to the third sub-surface 423 , and the second sub-surface 422 is perpendicular to the first sub-surface 421 and the third sub-surface 423 .

[0138] It can be understood that the orthographic projection of the third sub-surface 423 on the bearing surface 521 falls within the range of the bearing surface 521 .

[0139] It can be understood that the second sub-surface 422 is bent in a direction away from the first surface 12 (ie, toward the second surface 13 ) compared to the third sub-surface 423 .

[0140] In this embodiment, the upper plastic 50 includes a first insulating portion 51, a second insulating portion 52 and a third insulating portion 53 which are bent and connected in sequence. The first insulating portion 51 and the third insulating portion 53 are bent in opposite directions compared to the second insulating portion 52; the first insulating portion 51 is located in the mounting hole 11 and between the first penetration portion 31 and the top cover 10; the second insulating portion 52 is at least partially embedded in the side of the top cover 10 away from the first surface 12, and the second insulating portion 52 is used to support the pressure ring 40. The second insulating portion 52 has a bearing surface 521 facing the pressure ring 40; the third insulating portion 53 is arranged around the outer periphery of the pressure ring 40; this can better insulate the top cover 10 from the pole 30, and the top cover 10 from the pressure ring 40. In addition, it can better ensure the compression amount of the lower plastic and the sealing ring 60, thereby having better sealing performance. In addition, the bearing surface 521 is flush with the first step surface 311 or the bearing surface 521 is arranged closer to the first surface 12 than the first step surface 311, and the pressure ring 40 faces the side of the first penetration portion 31 and has an avoidance groove 42 corresponding to the position of the first step surface 311, so that the clearance between the pressure ring 40 and the first step surface 311 is matched. In this way, during assembly, before laser welding, when the welding tool supports the pressure ring 40, it can better prevent the pressure ring 40 from interfering with the first step surface 311, thereby better avoiding deformation of the surface pressure ring 40, so that the compression amount of the upper plastic 50 and the sealing ring 60 has better stability, and the compression amount of the upper plastic 50 and the sealing ring 60 of different end cover assemblies 100 is more consistent.

[0141] Please see again Figure 8 and Figure 10 In some embodiments, the pole 30 further includes a flange portion 34, which is arranged on the side of the first penetration portion 31 away from the second penetration portion 32. The flange portion 34 is located on the first surface 12 side of the top cover 10, and along a direction perpendicular to the arrangement direction of the first surface 12 and the second surface 13, the outer periphery of the flange portion 34 expands outward compared to the outer periphery of the first penetration portion 31.

[0142] It can be understood that along the arrangement direction of the first surface 12 and the second surface 13 , the flange portion 34 , the first penetration portion 31 , the second penetration portion 32 and the protruding portion 33 are arranged and connected in sequence.

[0143] It should be noted that the sealing ring 60 is located between the flange portion 34 and the top cover 10 , and respectively abuts against the flange portion 34 and the top cover 10 .

[0144] Please see again Figure 5In some embodiments, the end cap assembly 100 further includes a lower plastic 70, which is disposed on the first surface 12 side of the top cap 10 and is located between the flange portion 34 and the top cap 10. It is understood that the surface of the flange portion 34 facing the first penetration portion 31 abuts against the lower plastic 70.

[0145] Optionally, the lower plastic 70 is made of resin.

[0146] Mentioning "embodiments" and "implementation methods" in this application means that the specific features, structures or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrases in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments. In addition, it should be understood that the features, structures or characteristics described in the various embodiments of the present application can be arbitrarily combined to form another embodiment that does not deviate from the spirit and scope of the technical solution of the present application, unless there is a contradiction between them.

[0147] Finally, it should be noted that the above implementation modes are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the above preferred implementation modes, ordinary technicians in this field should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. An end cap assembly, characterized in that: include: a top cover, the top cover having a mounting hole, a first surface and a second surface disposed opposite to each other, the mounting hole respectively passing through the first surface and the second surface; A pole, the pole comprising a first penetration portion and a second penetration portion, the first penetration portion being penetrated through the mounting hole, the second penetration portion being protruded from a side of the first penetration portion close to the second surface, and the second penetration portion at least partially protruding from a side of the top cover facing away from the first surface; as well as A pressure ring is sleeved on the outer circumference of the second penetration portion, the maximum gap between the second penetration portion and the pressure ring is X, and the thickness of the pressure ring along the arrangement direction of the first surface and the second surface is T, then the end cover assembly satisfies: X≤T·tan5°.

2. The end cap assembly according to claim 1, wherein: The maximum gap X between the second penetration portion and the pressure ring is in the range of 0.02 mm ≤ X ≤ 0.17 mm.

3. The end cap assembly according to claim 1, wherein: The range of the thickness T of the pressure ring is: 1mm≤T≤2.5mm.

4. The end cap assembly according to claim 1, wherein: The second penetration portion has an outer peripheral side wall, and the pressure ring has an inner peripheral side wall. The end of the outer peripheral side wall facing away from the first penetration portion and the end of the inner peripheral side wall close to the first penetration portion form an annular surface, and the angle between the annular surface and the inner peripheral side wall is α, where α≤5°.

5. The end cap assembly according to claim 1, wherein: The first penetrating portion has a first stepped surface facing away from the first surface, and the first stepped surface is arranged around the periphery of the second penetrating portion; the line width w1 of the first stepped surface is in the range of 0.2 mm ≤ w1 ≤ 2 mm.

6. The end cap assembly according to claim 1, wherein: The pole further has a protruding portion, which is protruding from the surface of the second penetration portion away from the first penetration portion. The second penetration portion has a second step surface away from the first penetration portion, and the second step surface is arranged around the outer periphery of the protruding portion.

7. The end cap assembly according to claim 6, wherein: The line width w2 of the second step surface is in the range of 0.3 mm ≤ w2 ≤ 1.5 mm.

8. The end cap assembly according to claim 5, wherein: The end cover assembly also includes an upper plastic, which is spaced apart from the pole. The upper plastic portion is located between the first penetration portion and the top cover, and is used to insulate the pole from the top cover. The upper plastic portion is also partially located between the pressure ring and the top cover, and is used to insulate the pressure ring from the top cover. Along the thickness direction of the pressure ring, the pressure ring abuts against the upper plastic, and the pressure ring is gap-fitted with the first step surface.

9. The end cap assembly according to claim 8, wherein: Along the thickness direction of the pressure ring, the range of the gap d between the pressure ring and the first step surface is: 0.01 mm≤d≤0.5 mm.

10. The end cap assembly according to claim 9, wherein: The upper plastic includes a first insulating portion, a second insulating portion, and a third insulating portion that are bent and connected in sequence, and the first insulating portion and the third insulating portion are bent in opposite directions compared to the second insulating portion; the first insulating portion is located in the mounting hole and between the first penetration portion and the top cover; the second insulating portion is at least partially embedded in the side of the top cover away from the first surface, and the second insulating portion has a bearing surface facing the pressure ring, and the bearing surface is used to bear the pressure ring, and the pressure ring is in contact with the bearing surface; the third insulating portion is arranged around the outer circumference of the pressure ring; the first step surface is arranged closer to the first surface than the bearing surface.

11. The end cap assembly according to claim 9, wherein: The upper plastic includes a first insulating portion, a second insulating portion and a third insulating portion that are bent and connected in sequence, and the first insulating portion and the third insulating portion are bent in opposite directions compared to the second insulating portion; the first insulating portion is located in the mounting hole and between the first penetration portion and the top cover; the second insulating portion is at least partially embedded in the side of the top cover away from the first surface, and the second insulating portion has a bearing surface facing the pressure ring, and the bearing surface is used to bear the pressure ring; the third insulating portion is arranged around the outer circumference of the pressure ring; the bearing surface is flush with the first step surface or the bearing surface is arranged closer to the first surface than the first step surface, and the pressure ring has an avoidance groove on the side facing the first penetration portion and corresponding to the position of the first step surface.

12. A battery cell, characterized in that: include: case; The end cap assembly according to any one of claims 1 to 11, wherein the end cap assembly and the shell form a receiving cavity; as well as An electrode assembly is disposed in the receiving cavity and is electrically connected to the pole of the end cap assembly.

13. An energy storage device, characterized in that: include: a box body having a receiving cavity; and A plurality of battery cells according to claim 12, wherein the plurality of battery cells are accommodated in the accommodating cavity.

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