Top cover assembly, battery cell and battery pack

Abstract

The present disclosure relates to a top cover assembly, a battery monomer and a battery pack, and belongs to the technical field of batteries. The top cover assembly comprises a top cover, a pole, a conductive sheet and a sealing ring. The top cover and the conductive sheet both have through holes. The conductive sheet is located on the surface of the top cover, and the through hole of the conductive sheet is opposite to the through hole of the top cover in the axial direction. The sealing ring is located on the surface of the conductive sheet facing the top cover and surrounds the through hole of the conductive sheet. The pole has a first column and a second column. The diameter of the first column is larger than that of the second column. The first column and the second column have a first chamfer therebetween. The inner ring surface of the sealing ring and the end surface of the sealing ring have a third chamfer therebetween. The first column is located in the through hole of the top cover, and the second column is located in the through hole of the conductive sheet, and the second column is fixedly connected with the conductive sheet. The sealing ring is in a compressed state, and the first chamfer is in contact with the third chamfer. The present disclosure can improve the sealing performance of the top cover assembly.

Description

Technical Field

[0001] This disclosure relates to the field of battery technology, and in particular to a top cover assembly, a battery cell, and a battery pack. Background Technology

[0002] With the energy transition towards green and low-carbon directions, new energy lithium batteries, as a key technology for achieving low-carbon goals, have developed particularly rapidly in recent years. Behind the rapid development of the lithium battery industry, the reliability and sealing of the smallest unit of lithium batteries, the battery cell, are increasingly being challenged.

[0003] A single battery cell mainly consists of a bottom shell, a top cover assembly, a positive electrode, a negative electrode, a separator, and an electrolyte. The positive electrode, negative electrode, separator, and electrolyte are arranged in the bottom shell, and the top cover assembly is sealed on top of the bottom shell. Figure 1 As shown, the top cover assembly includes a top cover, a positive terminal, and a negative terminal. Currently, the positive and negative terminals are typically inserted from the inside out into the bottom casing, thus electrically connecting to the positive and negative terminals respectively. (Continue to refer to...) Figure 1 As shown, the top cover has through holes, with the positive terminal inserted and fixed in one through hole, and the negative terminal inserted and fixed in another through hole.

[0004] Because the top cover has a through-hole for inserting the electrode post, the electrolyte inside the bottom case will leak out through the through-hole. Therefore, refer to... Figure 1 As shown, a sealing ring is fitted around the pole post to ensure the sealing of the top cover assembly, for example, refer to Figure 1 As shown, a sealing ring is arranged between the top cover and the conductive sheet used to achieve electrical connection. The pole passes through the through hole of the top cover and the inner ring of the sealing ring, and extends into the through hole of the conductive sheet. Then the pole is welded to the conductive sheet to achieve electrical connection. At this time, the sealing ring is compressed between the top cover and the conductive sheet.

[0005] However, for reference Figure 1 As shown, if a poor weld or crack occurs at the weld between the electrode post and the conductive sheet, the electrolyte inside the bottom shell can still flow along... Figure 1 The path shown leaks outwards, therefore, the sealing performance of the current top cover assembly still needs improvement. Utility Model Content

[0006] To address the problems of the prior art, this disclosure provides a top cover assembly, a battery cell, and a battery pack. The technical solution is as follows:

[0007] In one aspect, a top cover assembly is provided, including a top cover, an electrode post, a conductive sheet, and a sealing ring;

[0008] Both the top cover and the conductive sheet have through holes. The conductive sheet is located on the surface of the top cover, and the through holes of the conductive sheet and the top cover are axially opposite each other. The sealing ring is located on the surface of the conductive sheet facing the top cover and surrounds the through hole of the conductive sheet.

[0009] The pole post has a first column and a second column in the axial direction. The diameter of the first column is larger than the diameter of the second column. There is a first chamfer between the first column and the second column. There is a third chamfer between the inner ring surface of the sealing ring and the end face of the sealing ring.

[0010] The first column is located in the through hole of the top cover, the second column is located in the through hole of the conductive sheet, and the second column is fixedly connected to the conductive sheet. The sealing ring is in a compressed state, and the first chamfer is in contact with the third chamfer.

[0011] Optionally, the inner ring surface of the sealing ring has a third chamfer between it and the top and bottom end faces of the sealing ring, and the two third chamfers are symmetrical about the center face of the sealing ring.

[0012] Optionally, the conductive sheet has a sealing groove on the surface facing the top cover, the depth of the sealing groove being less than the thickness of the sealing ring, and the sealing ring being embedded in the sealing groove.

[0013] Optionally, the first chamfer is connected to the axial end face of the first column, and there is a distance H between the connection between the first chamfer and the first column and the radial outer surface of the first column, and the axial end face of the first column is pressed against the end face of the sealing ring.

[0014] Optionally, the diameter of the through hole in the top cover is larger than the diameter of the outer ring of the sealing ring, and the sealing ring is located in the through hole of the top cover.

[0015] Optionally, the diameter of the through hole in the top cover is larger than the diameter of the inner ring of the sealing ring and smaller than the diameter of the outer ring of the sealing ring, and the sealing ring is compressed between the top cover and the conductive sheet.

[0016] Optionally, the inner wall of the through hole of the conductive sheet has a fourth chamfer between it and the surface of the conductive sheet facing the top cover.

[0017] Optionally, a second chamfer is provided between the first chamfer and the second column, and the second chamfer fits into the fourth chamfer.

[0018] Optionally, the conductive sheet has a recessed groove on the surface opposite to the top cover, surrounding a through hole in the conductive sheet.

[0019] The conductive sheet and the second column are welded together, and the weld (6) between the conductive sheet and the second column is contained in the settling tank.

[0020] Optionally, the pole post further has a pole post cap, which is connected to the axial end face of the first post opposite to the second post.

[0021] The pole cap is attached to the surface of the top cover opposite to the conductive sheet.

[0022] Optionally, the top cover is made of metal, and the top cover assembly further includes a first insulating member and a second insulating member;

[0023] The first insulating element is located in the through hole of the top cover and is sleeved on the body of the first post, for electrically isolating the top cover and the pole post;

[0024] The second insulating element is sleeved outside the sealing ring and located between the top cover and the conductive sheet, for electrically isolating the top cover and the conductive sheet.

[0025] In a second aspect, a battery cell is provided, the battery cell including a bottom shell, a cell and a top cover assembly as described in the first aspect or any one of the first aspects;

[0026] The battery cell is located in the bottom shell, the top cover assembly is fixed to the top of the bottom shell, and the terminal of the top cover assembly is electrically connected to the electrode of the battery cell.

[0027] Thirdly, a battery pack is provided, the battery pack including a battery management system and the battery cells described in the second aspect;

[0028] The number of battery cells is multiple, and the multiple battery cells are electrically connected in series or parallel. The battery management system is used to monitor and manage the status of each battery cell.

[0029] In the scheme disclosed herein, the electrode post has a first chamfer, and the sealing ring has a chamfer. The first chamfer of the electrode post fits together with the third chamfer of the sealing ring. Thus, the first chamfer of the electrode post can press against the third chamfer of the sealing ring. In this compressed state, the sealing ring will exert a force on the electrode post at its third chamfer, so that the sealing ring can also tightly abut against the electrode post. Therefore, the top end of the sealing ring has a good seal with the contacted components (such as the top cover and / or the first post), the bottom end of the sealing ring has a good seal with the conductive sheet, and the inner ring of the sealing ring has a good seal between its third chamfer and the first chamfer of the electrode post. This achieves a seal without dead angles and improves the sealing performance of the top cover assembly. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of a top cover assembly provided by existing technology;

[0032] Figure 2 This is a schematic diagram of the pole post before it is inserted into the top cover, according to an exemplary embodiment of this disclosure;

[0033] Figure 3 This is a schematic diagram of a top cover assembly provided in an exemplary embodiment of this disclosure;

[0034] Figure 4 This is a schematic diagram of the structure of a sealing ring provided in an exemplary embodiment of this disclosure;

[0035] Figure 5 This is a schematic diagram of the structure of another sealing ring provided in an exemplary embodiment of this disclosure;

[0036] Figure 6 This is a schematic diagram of the structure of a conductive sheet provided in an exemplary embodiment of this disclosure;

[0037] Figure 7 This is a schematic diagram of another top cover assembly provided in an exemplary embodiment of this disclosure;

[0038] Figure 8 yes Figure 7 An enlarged view at point A;

[0039] Figure 9 This is a schematic diagram of the pole structure provided in an exemplary embodiment of this disclosure;

[0040] Figure 10 This is a schematic diagram of another top cover assembly provided in an exemplary embodiment of this disclosure;

[0041] Figure 11 yes Figure 10 An enlarged view at point B;

[0042] Figure 12 This is a schematic diagram of another top cover assembly provided in an exemplary embodiment of this disclosure;

[0043] Figure 13 This is a schematic diagram of another top cover assembly provided in an exemplary embodiment of this disclosure;

[0044] Figure 14 yes Figure 13 Enlarged view at point C;

[0045] Figure 15 This is a schematic diagram of another top cover assembly provided in an exemplary embodiment of this disclosure;

[0046] Figure 16 This is an exploded view of a top cover assembly provided in an exemplary embodiment of this disclosure;

[0047] Figure 17 This is a schematic diagram of the structure of a battery cell provided in an exemplary embodiment of this disclosure.

[0048] 1. Top cover; 11. Through hole of the top cover.

[0049] 2. Pole post; 21. First column; 22. Second column; 23. Pole post cap; 24. First chamfer; 25. Second chamfer.

[0050] 3. Conductive sheet; 31. Through hole of conductive sheet; 32. Sealing groove; 33. Fourth chamfer; 34. Settlement groove.

[0051] 4. Sealing ring; 41. Third chamfer.

[0052] 51. First insulating component; 52. Second insulating component.

[0053] 6. Welds. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0055] This embodiment relates to a battery cell, and more particularly to a top cover assembly for a battery cell. To better understand this embodiment, the battery cell will be introduced first.

[0056] A single battery cell, also known as a battery cell or battery cell, provides a voltage between 3V and 4V. A large number of single batteries are connected in series or parallel, and with the addition of a battery management system (BMS) and a cooling system, a battery pack is obtained. The battery pack is then installed in a car as a power source.

[0057] For ease of management, multiple individual batteries are usually assembled into a frame to form a battery module, also known as a battery pack. Then, multiple battery modules are connected in series or parallel, along with a battery management system and a cooling system, to form a battery pack.

[0058] It is evident that a single cell is the most basic and smallest unit in forming a battery pack, and is the cornerstone of the entire battery system.

[0059] In terms of appearance, a single battery cell includes a top cover assembly and a bottom shell, which are fixed together. Inside is the core structure of the single battery cell (collectively referred to as the cell). The cell mainly includes a positive electrode, a negative electrode, a separator that isolates the positive and negative electrodes to prevent short circuits, and an electrolyte.

[0060] The positive electrode, as the main part for energy storage, is generally made of lithium compounds. The negative electrode, which releases energy, is generally made of carbon materials (such as graphite) or other non-metallic materials. The separator is usually made of microporous plastic or cellulose materials, which have high porosity and good ionic conductivity. The electrolyte is the medium for conducting ions and is usually composed of organic solvents and electrolyte salts.

[0061] The top cover assembly and bottom shell serve as the outer casing of the individual battery cell, providing a seal to prevent internal electrolyte leakage. The top cover assembly has terminals, such as positive and negative terminals, that are electrically connected to the internal electrodes, thus also serving as an external electrical connection. The top cover assembly typically also includes a pressure relief valve to release pressure externally in case of excessive internal pressure, preventing the individual battery cell from exploding. Usually, the top cover assembly also has an injection port to inject electrolyte into the cavity formed by the top cover assembly and bottom shell.

[0062] Currently, the positive and negative terminals on the top cover assembly are inserted from the outside in, assembled within the top cover to electrically connect with the internal positive and negative terminals, respectively. For example, as... Figure 1 The diagram shows the structure of the top cover assembly. Since the positive and negative terminals are assembled in the same way within the top cover, Figure 1 The diagram only shows one of the poles mounted on the top cover. For ease of explanation, Figure 1 In the accompanying diagrams, the length of the top cover 1 in the left-right direction is taken as the x-axis (that is, the line connecting the positive and negative terminals is taken as the x-axis), the width of the top cover 1 is taken as the y-axis, and the thickness of the top cover 1 is taken as the z-axis (that is, the height of the battery cell is taken as the z-axis).

[0063] refer to Figure 1 As shown, the top cover assembly includes a top cover 1, a terminal post 2, and a conductive sheet 3. Both the top cover 1 and the conductive sheet 3 have through holes. The conductive sheet 3 is located on the first surface (also the inner surface or lower surface) of the top cover 1. Furthermore, the through holes of the top cover 1 and the conductive sheet 3 are axially opposite each other, for example, their axial center lines are aligned. The terminal post 2 passes through the through hole of the top cover 1 and extends into the through hole of the conductive sheet 3. The terminal post 2 and the conductive sheet 3 are welded together on the back side of the conductive sheet 3 facing the back side of the top cover 1, thus fixing the conductive sheet 3 to the terminal post 2 and achieving electrical connection. Figure 1 In the assembly of the top cover assembly and the bottom shell of the battery cell shown, the conductive sheet 3 is located in the sealed cavity formed by the top cover assembly and the bottom shell, and is connected to the internal electrodes. Thus, the terminal post 2 is electrically connected to the internal electrodes of the battery cell through the conductive sheet 3.

[0064] To prevent internal electrolyte from leaking outwards from the weld seam along the contact surfaces between the conductive sheet and the terminal post, the top cover 1 and the terminal post, and the conductive sheet 3 and the top cover 1, a sealing ring 4 is typically arranged on the upper surface of the conductive sheet 3 facing the top cover 1. For example, refer to... Figure 1 As shown, a sealing ring 4 is arranged between the conductive sheet 3 and the top cover 1. The sealing ring 4 is compressed between the top cover 1 and the conductive sheet 3, absorbing the gap between the lower surface of the top cover 1 and the upper surface of the conductive sheet 3, so that the electrolyte will not leak between the lower surface of the top cover 1 and the upper surface of the conductive sheet 3.

[0065] But continue to refer to Figure 1 As shown, there is no seal at the contact point between the inner wall of the through hole of the conductive sheet 3 and the electrode 2, and at the contact point between the inner wall of the through hole of the top cover 1 and the electrode 2. Although the sealing ring 4 is fitted over the cylindrical surface of the electrode 2, the inner wall of the inner ring of the sealing ring 4 is not tightly pressed against the cylindrical surface of the electrode 2. Therefore, there is also no seal at the contact point between the inner wall of the inner ring of the sealing ring 4 and the cylindrical surface of the electrode 2.

[0066] In this way, reference Figure 1 As shown by the curved arrow, if there is a poor weld or long-term fatigue cracking at the weld between the conductive sheet 3 and the terminal 2, the electrolyte inside the battery cell will leak out through the weld, via the contact interface between the inner wall of the through hole of the conductive sheet 3 and the cylindrical surface of the terminal 2, the contact interface between the inner ring of the sealing ring 4 and the cylindrical surface of the terminal 2, the contact interface between the inner wall of the through hole of the top cover 1 and the cylindrical surface of the terminal 2, and the contact interface between the upper surface of the top cover 1 and the lower surface of the terminal cap 23 of the terminal 2. In other words, the electrolyte inside the battery cell will leak out along... Figure 1 The route indicated by the arrow is leaking outwards.

[0067] Therefore, this embodiment provides a top cover assembly in which the inner ring of the sealing ring can also tightly abut against the surface of the electrode post 2, thereby preventing the electrolyte from leaking outward and ensuring the good sealing performance of the top cover assembly.

[0068] like Figure 2 and Figure 3 The diagram shown is a structural schematic of a top cover assembly provided in this embodiment. Figure 2 This is a schematic diagram before pole 2 is inserted into the top cover. Figure 3 This is a schematic diagram showing the terminals after they are inserted into the top cover. It should be noted that because the positive and negative terminals are fixed to the top cover in the same way, therefore... Figure 2 and Figure 3 The following figures illustrate the fixing method between a single pole and the top cover.

[0069] refer to Figure 2 As shown, the top cover assembly includes a top cover 1, an electrode post 2, a conductive sheet 3, and a sealing ring 4. Both the top cover 1 and the conductive sheet 3 have through holes extending through the thickness. (Refer to...) Figure 2 As shown, the top cover 1 has a through hole 11, and the conductive sheet 3 has a through hole 31. The conductive sheet 3 is located on the first surface of the top cover 1 (i.e., Figure 2 The lower surface of the conductive sheet 3 is aligned with the through hole 31 of the top cover 1, and the two are connected. An annular sealing ring 4 is located on the upper surface of the conductive sheet 3 facing the top cover 1, for example, referring to... Figure 2 As shown, the sealing ring 4 is located between the lower surface of the top cover 1 and the upper surface of the conductive sheet 3. Moreover, the through hole 11 of the top cover 1, the inner ring of the sealing ring 4, and the through hole 31 of the conductive sheet 3 are connected.

[0070] Continue to refer to Figure 2 and Figure 3 As shown, the pole post 2 passes through the through hole of the top cover 1 and the inner ring of the sealing ring 4, and extends into the through hole 31 of the conductive sheet 3. A circular weld is formed at the joint between the cylindrical surface of the pole post 2 on the lower surface of the conductive sheet 3 and the inner wall of the through hole 31 of the conductive sheet 3 (because the cross-sectional shape of the pole post 2 is circular, the through hole of the top cover 1 and the conductive sheet 3 is also circular).

[0071] To reinforce the fixed connection between the electrode post 2, the top cover 1, and the conductive sheet 3, refer to Figure 2 As shown, the pole post 2 typically includes a pole body and a pole post cap 23. The area of ​​the pole post cap 23 is larger than the cross-section of the pole body. The shape of the pole post cap 23 can be quadrilateral or circular (as shown in the reference). Figure 16 As shown, the pole cap 23 is quadrilateral in shape.

[0072] refer to Figure 3 As shown, the post 2 is located in the through hole 11 of the top cover 1, the inner ring of the sealing ring 4, and the through hole 31 of the conductive sheet 3, while the post cap 23 is hung on the second surface of the top cover 1 (i.e., the upper surface in the figure, which is also the outer surface of the top cover 1). In this way, with the post cap 23 hanging on the upper surface of the top cover 1 and the bottom of the post 2 welded to the conductive sheet 3, the sealing ring 4 between the top cover 1 and the conductive sheet 3 will be better compressed between the top cover 1 and the conductive sheet 3, ensuring good sealing performance.

[0073] To solve the problem that the inner ring of sealing ring 4 cannot tightly abut against the cylindrical surface of pole post 2, refer to Figure 2As shown, the pole post 2 includes a first pole post 21 and a second pole post 22 with different diameters, such as the diameter of the first pole post 21 being larger than the diameter of the second pole post 22. Because the diameters of the first pole post 21 and the second pole post 22 are different, a chamfer can be provided between the first pole post 21 and the second pole post 22. Therefore, refer to... Figure 2 As shown, there is a chamfer (denoted as the first chamfer 24) between the first column 21 and the second column 22.

[0074] like Figure 4 The image shown is a schematic diagram of the cross-sectional structure of sealing ring 4. (Refer to...) Figure 4 As shown, the inner ring surface of the sealing ring 4 and the end face of the sealing ring 4 also have a chamfer (denoted as the third chamfer 41), wherein the angle of the third chamfer 41 and the first chamfer 24 can be equal.

[0075] So, reference Figure 3 As shown, after the pole post 2 passes through the through hole 11 of the top cover 1 and the inner ring of the sealing ring 4, and extends into the through hole 31 of the conductive sheet 3, the first chamfer 24 on the pole post 2 presses on the third chamfer 41 of the sealing ring 4. After the pole post 2 is welded to the conductive sheet 3, the sealing ring 4 is compressed between the lower surface of the top cover 1 and the upper surface of the conductive sheet 3.

[0076] After the sealing ring 4 is compressed between the lower surface of the top cover 1 and the upper surface of the conductive sheet 3, the direction of the elastic force of the sealing ring 4 at the third chamfer 41 is oblique relative to the z-axis, with a component force parallel to the xy plane and pointing towards the axis of the pole post 2, which causes the sealing ring 4 to tightly abut against the first chamfer 24 of the pole post 2 at the third chamfer 41 (because the third chamfer 41 and the first chamfer 24 are equal, the two can fit together, but even if the third chamfer 41 and the first chamfer 24 are different, the two can still fit together, because the sealing ring 4 is flexible and can deform, which can also cause the third chamfer 41 to fit tightly against the first chamfer 24). Therefore, the sealing ring 4 is sealed to the upper surface of the conductive sheet 3, the sealing ring 4 is sealed to the lower surface of the top cover 1, and the third chamfer 41 of the sealing ring 4 is sealed to the first chamfer 24 of the pole post 2. Thus, even if leakage occurs at the weld between the pole post 2 and the conductive sheet 3, the leakage path is sealed in both the horizontal and vertical directions, thereby stopping the leakage of electrolyte and ensuring the good sealing performance of the top cover assembly.

[0077] refer to Figure 3 As shown, the sealing ring 4 is assembled between the lower surface of the top cover 1 and the upper surface of the conductive sheet 3, and the third chamfer 41 of the sealing ring 4 needs to face away from the conductive sheet 3. Therefore, the sealing ring 4 must not be installed backwards when it is installed between the top cover 1 and the conductive sheet 3.

[0078] In one example, to avoid installing the sealing ring 4 backwards, such as Figure 5 The diagram shown is another structural schematic of the sealing ring 4. (Refer to...) Figure 5 As shown, the inner ring surface of the sealing ring 4 has a third chamfer 41 between the top end face and the bottom end face of the sealing ring 4, and the absolute values ​​of the angles of the third chamfer 41 at the top end and the third chamfer 41 at the bottom end are equal. It can also be understood that the third chamfer 41 at the top end and the third chamfer 41 at the bottom end are symmetrical about the center face of the sealing ring 4. The center face of the sealing ring 4 is parallel to the plane on which the sealing ring 4 is located and passes through the center of the sealing ring 4.

[0079] Therefore, when the sealing ring 4 is inserted between the lower surface of the top cover 1 and the upper surface of the conductive sheet 3, the sealing ring 4 is not installed backwards. Since the sealing ring 4 is not installed backwards, the top cover assembly can be assembled using a robotic arm, achieving automated assembly of the top cover assembly and improving assembly efficiency.

[0080] In one example, to further improve the assembly efficiency of the sealing ring 4, such as Figure 6 The image shown is a cross-sectional schematic diagram of conductive sheet 3. (Refer to...) Figure 6 As shown, the first surface of the conductive sheet 3 (i.e. Figure 3 The upper surface of the sealing ring 4 has a sealing groove 32, the depth of which is less than the thickness of the sealing ring 4. Figure 7 and Figure 8 As shown, the sealing ring 4 is embedded in the sealing groove 32 of the conductive sheet 3.

[0081] The sealing groove 32 can position and limit the sealing ring 4, which is beneficial for automated assembly. For example, the robotic arm can first place the sealing ring 4 in the sealing groove 32 of the conductive sheet 3, then place the conductive sheet 3 with the sealing ring 4 on the lower surface of the top cover 1, and then insert the pole 2 from the top cover 1 through the through hole 11 of the top cover 1, the inner ring of the sealing ring 4 and the through hole 31 of the conductive sheet 3. After clamping the pole 2, the top cover 1 and the conductive sheet 3 (such as clamping until the sealing ring 4 can no longer be compressed), the conductive sheet 3 is welded and fixed to the pole 2 on the lower surface of the conductive sheet 3.

[0082] In one example, the sealing groove 32 of the conductive sheet 3 and the through hole 31 of the conductive sheet 3 may or may not be connected. If the sealing groove 32 and the through hole 31 are connected, that is, refer to... Figure 6 As shown, the sealing groove 32 has no groove wall at the position adjacent to the through hole 31. However, it should be noted that because both ends of the sealing ring 4 have a third chamfer 41, the thickness of the sealing ring 4 at the position of the third chamfer 41 is relatively thin. The sealing ring 4 is also flexible. As a result, when the pole post 2 extends into the through hole 31 of the conductive sheet 3, the sealing ring 4 at the position of the third chamfer 41 will also enter into the through hole 31 of the conductive sheet 3, affecting the positioning of the sealing ring 4 and reducing the assembly efficiency.

[0083] Therefore, refer to Figure 6 As shown, the sealing groove 32 and the through hole 31 of the conductive sheet 3 are not connected. The sealing groove 32 is annular and surrounds the through hole 31.

[0084] In one example, such as Figure 9 The diagram shown is a structural schematic of pole post 2. (Refer to...) Figure 9 As shown, a first chamfer 24 between the first column 21 and the second column 22 is connected to the axial end face of the first column 21, and the connection point between the first chamfer 24 and the first column 21 has a distance H between it and the radial outer surface of the first column 21. Thus, referring to... Figure 10 and Figure 11 As shown, the axial end face of the first column 21 can press against the end face of the sealing ring 4.

[0085] It can also be understood as, reference Figure 9 As shown, the first chamfer 24 is not cut from the radial surface (i.e., cylindrical surface) of the first column 21, nor is it connected to the cylindrical surface of the first column 21. Instead, it is offset from the cylindrical surface of the first column 21 and connected to the axial end face of the first column 21. This results in a platform with a radial width of H between the connection point of the first chamfer 24 and the cylindrical surface of the first column 21. (Refer to...) Figure 11 As shown, the platform can be pressed against the end face of the sealing ring 4. This enhances the sealing performance between the sealing ring 4 and the pole post 2.

[0086] Regarding the size of the spacing H: The spacing H can be relatively small, refer to... Figure 10 and Figure 11 As shown, the end face of the sealing ring 4 facing away from the conductive sheet 3 (i.e., the top end face in the figure) is partially pressed by the axial end face of the first column 21 and partially pressed by the lower surface of the top cover 1. In this design, the diameter of the through hole of the top cover 1 is larger than the diameter of the inner ring of the sealing ring 4 and smaller than the diameter of the outer ring of the sealing ring 4.

[0087] In another example, the spacing H can also be relatively large, see reference. Figure 12 As shown, the top end face of the sealing ring 4, facing away from the conductive sheet 3, is entirely pressed against the axial port of the first pillar 21. In this design, the sealing ring 4 is compressed between the first pillar 21 and the conductive sheet 3, and the diameter of the through hole 11 of the top cover 1 is larger than the diameter of the outer ring formed by the outer ring wall of the sealing ring 4. Alternatively, the conductive sheet 3 can be understood as being located on the lower surface of the top cover 1, with the through hole 31 of the conductive sheet 3 located within the through hole 11 of the top cover 1, and the sealing groove 32 of the conductive sheet 3 also located within the through hole 11 of the top cover 1. The diameter of the first pillar 21 is larger than the diameter of the inner ring of the sealing ring 4. The diameter of the first pillar 21 can also be larger than the diameter of the outer ring formed by the outer ring wall of the sealing ring 4, but the diameter of the first pillar 21 must be smaller than the diameter of the through hole of the top cover 1.

[0088] It should be noted that, for reference Figure 12 As shown, there can be a gap between the cylindrical surface of the first column 21 and the inner wall of the through hole 11 of the top cover 1. Because the axial end face of the first column 21 is sealed with the top end face of the sealing ring 4, even if there is a gap between the first column 21 and the through hole 11 of the top cover 1, electrolyte leakage will not occur.

[0089] However, reference Figure 12 As shown, the smaller the gap between the cylindrical surface of the second pillar 22 and the through hole 31 of the conductive sheet 3, the better. While allowing the second pillar 22 to extend into the through hole 31 of the conductive sheet 3, the smaller the gap between the cylindrical surface of the second pillar 22 and the inner wall of the through hole 31, the better. This is because a smaller gap between the cylindrical surface of the second pillar 22 and the inner wall of the through hole 31 means that the weld formed after welding the second pillar 22 and the conductive sheet 3 on the lower surface of the conductive sheet 3 is less likely to have a weak weld. Since the weld is the source of leakage, the sealing performance of the top cover assembly is better.

[0090] Continue to refer to Figure 12 As shown, the gap between the cylindrical surface of the second pillar 22 and the through hole 31 of the conductive sheet 3 is small. That is, although the diameter of the second pillar 22 is smaller than the diameter of the through hole 31 of the conductive sheet 3, they are very close. In this case, it is more difficult for the second pillar 22 to extend into the through hole 31 of the conductive sheet 3.

[0091] Therefore, refer to Figure 11 As shown, the inner wall of the through hole 31 of the conductive sheet 3 has a chamfer (denoted as the fourth chamfer 33) between it and the first surface of the conductive sheet 3 (i.e., the surface facing the top cover 1, which is also the upper surface). The fourth chamfer 33 of the conductive sheet 3 is flared. The diameter of the through hole 31 of the conductive sheet 3 is larger at the fourth chamfer 33. Therefore, the second column 22 can be smoothly inserted into the through hole 31 of the conductive sheet 3. Once the second column 22 enters the through hole 31 of the conductive sheet 3, it can be smoothly positioned in the through hole 31 of the conductive sheet 3 with the help of the lubricant on the surface of the second column 22 and / or the inner wall of the through hole 31 of the conductive sheet 3.

[0092] In order to match the fourth chamfer 33 of the conductive sheet 3, refer to Figure 9 As shown, the first chamfer 24 between the first column 21 and the second column 22 also has a second chamfer 25 with the second column 22. The angle of the second chamfer 25 is equal to the angle of the fourth chamfer 33 of the conductive sheet 3. Thus, the reference... Figure 11 As shown, the second chamfer 25 is attached to the fourth chamfer 33 of the conductive sheet 3.

[0093] It should be noted that because the sealing groove 32 and the through hole 31 of the conductive sheet 3 are not connected, there is a horizontal platform between the sealing groove 32 and the through hole 31. Therefore, refer to... Figure 9 As shown, there is also a horizontal platform parallel to the xy plane between the second chamfer 25 and the first chamfer 24. That is, there is a radial gap between the first chamfer 24 and the second chamfer 25, which is equivalent to the radial gap between the sealing groove 32 of the conductive sheet 3 and the fourth chamfer 33.

[0094] It should be noted that the second chamfer 25 may not be provided between the first column 21 and the second column 22. In this case, please refer to Figure 11 As shown, after the second post 22 is welded to the conductive sheet 3, a gap will be generated between the post 2 and the through hole 31 of the conductive sheet 3 at the fourth chamfer 33 of the conductive sheet 3. However, due to the sealing of the weld and the sealing ring, the electrolyte will not leak.

[0095] In one example, within the xy-plane (i.e., the horizontal plane) containing the lower surface of the conductive sheet 3, there will be a weld between the second pillar 22 and the through hole 31. To accommodate the weld, accordingly, such as Figure 13 and Figure 14 As shown, the lower surface of the conductive sheet 3 facing away from the top cover 1 has a recessed groove 34. The recessed groove 34 is arranged around the through hole 31, which can also be understood as the through hole 31 being arranged in the recessed groove 34.

[0096] Thus, for reference Figure 14 As shown, on the lower surface of the conductive sheet 3, after the electrode post 2 and the conductive sheet 3 are welded at the through hole 31, the weld 6 formed is contained in the sink 34.

[0097] As described above, the above scheme is explained using one of the positive and negative terminals as an example. However, it should be noted that, to avoid a short circuit due to the interconnection of the positive and negative terminals, the conductive piece 3 welded to the positive terminal is not the same conductive piece as the conductive piece 3 welded to the negative terminal. That is, as shown above... Figure 16 As shown, the top cover assembly needs to include two conductive sheets 3, one of which is used to weld to the positive terminal 2A, and the other conductive sheet 3 is used to weld to the negative terminal 2B.

[0098] Continue to refer to Figure 16 As shown, there are also two sealing rings 4, one fitted outside the positive terminal 2A and the other fitted outside the negative terminal 2B.

[0099] As for top cover 1, you can also refer to... Figure 16As shown, the positive terminal 2A and the negative terminal 2B can be inserted into the same top cover 1. Therefore, the top cover 1 has a through hole 31 for inserting the positive terminal 2A and a through hole 31 for inserting the negative terminal 2B.

[0100] When the top cover 1 is made of insulating material, although the positive and negative terminals are inserted into the same top cover 1, because the top cover 1 is made of insulating material, there will be no short circuit between the positive and negative terminals through the top cover 1.

[0101] If the top cover 1 is made of metal, then if the positive and negative terminals are inserted into the same top cover 1, a short circuit will occur because the positive and negative terminals are connected through the top cover 1. For example, the top cover 1 may be made of aluminum, and the bottom shell of the battery cell may also be made of aluminum to facilitate welding between the top cover 1 and the bottom shell.

[0102] Therefore, in the design where the top cover 1 is made of metal, such as... Figure 15 As shown, the top cover assembly also includes a first insulating member 51 and a second insulating member 52, wherein the first insulating member 51 isolates the top cover 1 from the terminal post 2, and the second insulating member 52 isolates the top cover 1 from the conductive sheet 3. In this way, the top cover 1 does not contact either the terminal post 2 or the conductive sheet 3.

[0103] For example, refer to Figure 15 As shown, the first insulating member 51 is located in the through hole 11 of the top cover 1 and is fitted over the first column 21 to prevent the cylindrical surface of the first column 21 from contacting the inner wall of the through hole 11 of the top cover 1. The second insulating member 52 is fitted over the sealing ring 4 and is located between the top cover 1 and the conductive sheet 3 to prevent the upper surface of the conductive sheet 3 from contacting the lower surface of the top cover 1.

[0104] As mentioned above, refer to Figure 15 As shown, the terminal post 2 also has a terminal post cap 23, the lower surface of which is attached to the upper surface of the top cover 1. Therefore, there is also an insulating element between the lower surface of the terminal post cap 23 and the upper surface of the top cover 1. (Reference) Figure 15 As shown, the first insulating member 51 has a sleeve, which is fitted over the first post 21 and located in the through hole 11 of the top cover 1. The first insulating member 51 also has a sleeve eave at one end of the sleeve, which is located between the lower surface of the pole cap 23 and the upper surface of the top cover 1, so that the pole cap 23 and the top cover 1 do not contact each other at any position.

[0105] Furthermore, to further ensure the electrical insulation between the pole cap 23 and the top cover 1, refer to Figure 15 As shown, the first insulating member 51 has an upward flange at the edge of the sleeve eaves. The flange is perpendicular to the sleeve eaves but parallel to the sleeve. The flange surrounds the cylindrical surface of the pole cap 23 near the bottom.

[0106] For the positive terminal, the positive terminal is insulated from the top cover 1 by a first insulating member 51, and the conductive sheet 3 welded to the positive terminal is insulated from the top cover 1 by a second insulating member 52. For the negative terminal, the negative terminal is insulated from the top cover 1 by a first insulating member 51, and the conductive sheet 3 welded to the negative terminal is insulated from the top cover 1 by a second insulating member 52.

[0107] The first insulating member 51 used for electrically isolating the positive terminal and the top cover 1 and the first insulating member 51 used for electrically isolating the negative terminal and the top cover 1 can be the same insulating member. Then, the first insulating member 51 has a sleeve, sleeve eaves and flanges fitted on the positive terminal, and also has a sleeve, sleeve eaves and flanges fitted on the negative terminal.

[0108] Or, refer to Figure 16 As shown, the first insulating member 51 used for electrically isolating the positive terminal and the top cover 1, and the first insulating member 51 used for electrically isolating the negative terminal and the top cover 1, are two first insulating members 51. That is, there are two first insulating members 51, one for electrically isolating the positive terminal 2A and the top cover 1, and the other for electrically isolating the negative terminal 2B and the top cover 1.

[0109] The second insulating element 52 used for electrically isolating one conductive sheet 3 from the top cover 1, and the second insulating element 52 used for electrically isolating another conductive sheet 3 from the top cover 1, can also be the same insulating element. (See reference) Figure 16 As shown, the second insulating member 52 has a similar structure to the top cover 1, and is also a plate-shaped structure. It is located on the lower surface (i.e., the inner surface) of the top cover 1, and has a through hole that fits around one sealing ring 4, and a through hole that fits around another sealing ring 4 (see reference). Figure 16 (As shown).

[0110] In one example, the electrode post 2 and the conductive sheet 3 are generally made of copper, while the first insulating component 51 and the second insulating component 52 are generally made of plastic. Additionally, to improve the external conductivity of the electrode post 2, a silver layer is typically plated onto the upper surface of the electrode cap 23.

[0111] In this embodiment, the electrode post has a first chamfer, and the sealing ring has a third chamfer. The first chamfer of the electrode post and the third chamfer of the sealing ring are fitted together. Thus, the first chamfer of the electrode post can press against the third chamfer. In this compressed state, the sealing ring will exert a force on the electrode post at its third chamfer, so that the sealing ring can also tightly abut against the electrode post. Therefore, the top end of the sealing ring has a good seal with the contacted component (such as the top cover and / or the first post), the bottom end of the sealing ring has a good seal with the conductive sheet, and the inner ring of the sealing ring has a good seal between the third chamfer and the first chamfer of the electrode post. This achieves a seal without dead angles and improves the sealing performance of the top cover assembly.

[0112] This embodiment also provides a single battery cell, such as Figure 17 As shown, the battery cell includes a bottom shell 200, a battery cell, and the aforementioned top cover assembly 100. The battery cell is located within the bottom shell 200, and the top cover assembly 100 is fixed to the top of the bottom shell 200. The terminals of the top cover assembly 100 are electrically connected to the electrodes of the battery cell. The battery cell includes a positive electrode, a negative electrode, a separator, and an electrolyte. For details, please refer to the above description; further elaboration is unnecessary.

[0113] Among them, the terminals of the top cover assembly are electrically connected to the battery cell, that is, the positive terminal 2A of the top cover assembly is electrically connected to the positive terminal, and the negative terminal 2B of the top cover assembly is electrically connected to the negative terminal.

[0114] This embodiment also provides a battery pack, which includes a battery management system and the aforementioned battery cells. There are multiple battery cells, which are electrically connected in series or in parallel. The battery management system is used to monitor and manage the status of each battery cell (such as charging status, discharging status, temperature, and voltage).

[0115] The above description is only a preferred embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A top cover assembly, characterized in that, It includes a top cover (1), an electrode post (2), a conductive sheet (3), and a sealing ring (4); Both the top cover (1) and the conductive sheet (3) have through holes. The conductive sheet (3) is located on the surface of the top cover (1), and the through hole of the conductive sheet (3) is axially opposite to the through hole of the top cover (1). The sealing ring (4) is located on the surface of the conductive sheet (3) facing the top cover (1) and surrounds the through hole of the conductive sheet (3). The pole post (2) has a first column (21) and a second column (22) in the axial direction. The diameter of the first column (21) is larger than the diameter of the second column (22). There is a first chamfer (24) between the first column (21) and the second column (22). There is a third chamfer (41) between the inner ring surface of the sealing ring (4) and the end face of the sealing ring (4). The first column (21) is located in the through hole of the top cover (1), the second column (22) is located in the through hole of the conductive sheet (3), and the second column (22) is fixedly connected to the conductive sheet (3). The sealing ring (4) is in a compressed state, and the first chamfer (24) is in contact with the third chamfer (41).

2. The top cover assembly according to claim 1, characterized in that, The inner ring surface of the sealing ring (4) has the third chamfer (41) between the top end face and the bottom end face of the sealing ring (4), and the two third chamfers (41) are symmetrical about the center face of the sealing ring (4).

3. The top cover assembly according to claim 1, characterized in that, The conductive sheet (3) has a sealing groove (32) on the surface facing the top cover (1), the depth of the sealing groove (32) is less than the thickness of the sealing ring (4), and the sealing ring (4) is embedded in the sealing groove (32).

4. The top cover assembly according to claim 1, characterized in that, The first chamfer (24) is connected to the axial end face of the first column (21), and there is a distance H between the connection between the first chamfer (24) and the first column (21) and the radial outer surface of the first column (21). The axial end face of the first column (21) is pressed against the end face of the sealing ring (4).

5. The top cover assembly according to claim 4, characterized in that, The diameter of the through hole of the top cover (1) is larger than the diameter of the outer ring of the sealing ring (4), and the sealing ring (4) is located in the through hole of the top cover (1).

6. The top cover assembly according to claim 1, characterized in that, The diameter of the through hole of the top cover (1) is larger than the diameter of the inner ring of the sealing ring (4) and smaller than the diameter of the outer ring of the sealing ring (4). The sealing ring (4) is compressed between the top cover (1) and the conductive sheet (3).

7. The top cover assembly according to claim 1, characterized in that, The inner wall of the through hole of the conductive sheet (3) has a fourth chamfer (33) between it and the surface of the conductive sheet (3) facing the top cover (1).

8. The top cover assembly according to claim 7, characterized in that, A second chamfer (25) is formed between the first chamfer (24) and the second column (22), and the second chamfer (25) fits into the fourth chamfer (33).

9. The top cover assembly according to any one of claims 1 to 8, characterized in that, On the surface of the conductive sheet (3) facing away from the top cover (1), there is a groove (34) surrounding the through hole of the conductive sheet (3); The conductive sheet (3) and the second column (22) are welded together, and the weld (6) between the conductive sheet (3) and the second column (22) is contained in the sink (34).

10. The top cover assembly according to any one of claims 1 to 8, characterized in that, The pole post (2) also has a pole post cap (23), which is connected to the axial end face of the first post (21) opposite to the second post (22); The pole cap (23) is attached to the surface of the top cover (1) opposite to the conductive sheet (3).

11. The top cover assembly according to any one of claims 1 to 8, characterized in that, The top cover (1) is made of metal, and the top cover assembly also includes a first insulating element (51) and a second insulating element (52); The first insulating element (51) is located in the through hole of the top cover (1) and is sleeved on the outside of the first column (21) for electrically isolating the top cover (1) and the pole post (2); The second insulating element (52) is fitted over the sealing ring (4) and is located between the top cover (1) and the conductive sheet (3) for electrically isolating the top cover (1) and the conductive sheet (3).

12. A single battery cell, characterized in that, The battery cell includes a bottom shell (200), a cell, and a top cover assembly (100) as described in any one of claims 1 to 11; The battery cell is located in the bottom shell (200), the top cover assembly (100) is fixed on the top of the bottom shell (200), and the terminal of the top cover assembly (100) is electrically connected to the electrode of the battery cell.

13. A battery pack, characterized in that, The battery pack includes a battery management system and the battery cells as described in claim 12; The number of battery cells is multiple, and the multiple battery cells are electrically connected in series or parallel. The battery management system is used to monitor and manage the status of each battery cell.

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