Top cover assembly and battery pack

Abstract

A top cover assembly (100) and a battery pack. The top cover assembly (100) comprises: a cover plate (10); an electrolyte injection hole (15), formed in the cover plate (10); a sealing element (20); and an elastic mechanism (30), wherein one end of the elastic mechanism (30) is connected to the sealing element (20), the elastic mechanism (30) is configured to be capable of being stretched out or compressed back in a first direction, and when the sealing element (20) is in a second position, the elastic mechanism (30) is in a compressed state so as to have elastic potential energy to drive the sealing element (20) to move from the second position to a first position.

Description

Top cover assembly and battery pack

[0001] This application claims priority to the Chinese patent applications filed with the China Patent Office on November 2, 2023, with application numbers 202311455843.6 and 202311455697.7. The entire contents of the above applications are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a top cover assembly and a battery pack. Background Art

[0003] The battery pack includes multiple battery cells, which include a shell, a top cover assembly, a negative electrode, a positive electrode, a diaphragm and an electrolyte. An injection hole is provided on the top cover assembly, and the electrolyte is injected into the interior of the shell through the injection hole. After the injection is completed, the injection hole is sealed by a sealing gasket and sealing particles. The electrolyte in the battery cell usually needs to be injected multiple times or some battery packs are configured so that the electrolyte is replenishable. SUMMARY OF THE INVENTION

[0004] In the related art, removing the sealing gasket and the sealing rubber particles used to seal the liquid injection hole is often complicated, especially the sealing rubber particles need to be removed with the help of tools and are difficult to operate.

[0005] In a first aspect, an embodiment of the present application provides a top cover assembly, the top cover assembly comprising:

[0006] cover;

[0007] A liquid injection hole is provided on the cover plate, and the liquid injection hole is used for a liquid injection device to replenish electrolyte into the interior of the battery cell;

[0008] a sealing element, the sealing element being configured to be movable relative to the cover plate along a first direction between a first position and a second position, wherein when the sealing element is in the first position, the sealing element is capable of sealing the liquid injection hole, and when the sealing element is in the second position, the sealing element is offset from the liquid injection hole;

[0009] An elastic mechanism, one end of which is connected to the sealing element, and the elastic mechanism is configured to be able to extend and retract along a first direction. When the sealing element is in a first position, the elastic mechanism is used to support the sealing element. When the sealing element is in a second position, the elastic mechanism is in a compressed state to have elastic potential energy to drive the sealing element to move from the second position to the first position.

[0010] In a second aspect, an embodiment of the present application provides a battery pack, wherein the battery pack includes a plurality of battery cells, and the battery cells include the above-mentioned top cover assembly. Beneficial effects

[0011] The top cover assembly provided in the present application connects a sealing element for sealing the liquid injection hole with an elastic mechanism, drives the sealing element to move in a first direction, so that the sealing element can be staggered with the liquid injection hole, and then the electrolyte can be replenished into the battery cell through the liquid injection hole. After removing the liquid injection device, the elastic mechanism can drive the sealing element to move in the opposite direction to seal the liquid injection hole. The liquid injection hole can be opened and closed through simple operations, which greatly improves the convenience of the liquid injection operation of the battery cell.

[0012] The battery pack provided in the present application includes a plurality of battery cells, each of which is designed based on the above-mentioned top cover assembly. The beneficial effects thereof can be found in the beneficial effects of the above-mentioned top cover assembly, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG1 is a perspective view of a top cover assembly provided in one embodiment of the present application;

[0014] FIG2 is a cross-sectional view of a top cover assembly provided in one embodiment of the present application;

[0015] FIG3 is a partial enlarged view of FIG2;

[0016] FIG4 is a perspective view of an insulating seat provided in one embodiment of the present application;

[0017] FIG5 is a perspective view of a sealing element provided in one embodiment of the present application;

[0018] FIG6 is a cross-sectional view of the top cover assembly when the sealing element is in the first position according to an embodiment of the present application;

[0019] FIG7 is a partial enlarged view of FIG6;

[0020] FIG8 is a cross-sectional view of the top cover assembly when the sealing element is in the second position according to an embodiment of the present application;

[0021] FIG9 is a partial enlarged view of FIG8;

[0022] FIG10 is a cross-sectional view of a top cover assembly provided in a first position according to another embodiment of the present application;

[0023] FIG11 is a partial enlarged view of FIG10;

[0024] FIG12 is a cross-sectional view of a top cover assembly provided in accordance with an embodiment of the present application;

[0025] FIG13 is a partial enlarged view of FIG12;

[0026] FIG14 is a perspective schematic diagram of a top cover assembly provided in an embodiment of the present application;

[0027] 15 is a cross-sectional view of a top cover assembly with a sealing element provided in a first position according to an embodiment of the present application;

[0028] FIG16 is a partial enlarged view of FIG15;

[0029] 17 is a cross-sectional view of the top cover assembly with the sealing element provided in the second position according to an embodiment of the present application;

[0030] FIG18 is a partial enlarged view of FIG17;

[0031] FIG19 is a schematic structural diagram of a top cover assembly provided in an embodiment of the present application;

[0032] FIG20 is a partial enlarged view of FIG19;

[0033] FIG21 is a perspective view of a sealing element provided in an embodiment of the present application;

[0034] FIG22 is a partial structural perspective view of a top cover assembly provided in an embodiment of the present application;

[0035] FIG23 is a partial enlarged view of FIG22;

[0036] FIG24 is a perspective view of a partial structure of a top cover assembly provided in an embodiment of the present application;

[0037] FIG25 is a partial enlarged view of FIG24;

[0038] FIG26 is a cross-sectional view of a top cover assembly provided by another embodiment of the present application

[0039] FIG27 is a partial enlarged view of FIG26;

[0040] FIG28 is a perspective view of a portion of the top cover assembly provided in an embodiment of the present application;

[0041] FIG29 is a partial enlarged view of FIG28;

[0042] Figure Number:

[0043] 100, top cover assembly; 10, cover plate; 101, outer surface; 102, inner surface; 11, upper plastic part; 12, insulating seat; 121, base portion; 122, extension portion; 1221, first cavity; 123, bottom wall; 1231, first portion of bottom wall; 1232, second portion of bottom wall; 124, liquid guide hole; 1224, support platform; 1225, tubular portion; 126, side wall; 13, pole; 131, first Pole; 132, second pole; 14, terminal; 15, injection hole; 151, first part; 152, second part; 153, step surface; 20, sealing element; 21, main body; 22, boss; 221, top surface; 222, side; 23, guide; 231, first guide; 232, second guide; 233, third guide; 24, connecting part; 241, first connecting part; 242, second Connecting portion; 243, third connecting portion; 30, elastic mechanism; 31, spring; 32, elastic member; 321, elastic support beam; 331, first elastic mechanism; 332, second elastic mechanism; 333, third elastic mechanism; 70, sealing plate; 200, injection device; 60, injection mechanism; 64, outlet; 61, pressing portion; 62, sleeve; 63, piston; 631, columnar portion; 632, base; 40, guide device 41. Second chamber; 42. Guide channel; 44. Cylindrical portion; 441. First cylindrical portion; 442. Second cylindrical portion; 443. Third cylindrical portion; 45. Opening; 50. Sealing sleeve; 51. First sealing sleeve; 52. Second sealing sleeve; 53. Third sealing sleeve; 501. Main body; 502. Extension portion; 200. Liquid injection device; 60. Injection mechanism; 61. Pressing portion; 62. Sleeve; 63. Piston; Modes for Carrying Out the Invention

[0044] Example 1

[0045] One embodiment of the present application provides a battery pack, which includes one or more single cells. The multiple single cells can be arranged to be connected in series, or the multiple single cells can be arranged to be connected in parallel, or the multiple single cells can be arranged to be a mixed connection of series and parallel, so that the battery pack has a capacity and power suitable for use by electrical equipment.

[0046] The battery pack also includes a connecting piece, which is used to connect multiple single cells so that the positive and negative electrodes of the multiple single cells have a stable series-parallel connection structure. Materials suitable for preparing the connecting piece include copper foil.

[0047] The battery pack also includes a box, which is used to fix and protect multiple single cells and other components. The box can be assembled from several sub-boxes. The materials suitable for preparing the box have good shock resistance, waterproofness and insulation properties. Suitable materials include metal or plastic materials.

[0048] The battery pack can be used in electrical devices including mobile phones, portable devices, laptops, electric bicycles, electric cars, electric boats, electric toys, electric tools, etc.

[0049] Depending on the safety performance requirements and space requirements of the applicable electrical equipment, the battery pack may also include a BMS (battery management system), which is used to monitor, protect and manage the working status of the battery pack. The BMS can monitor and balance the voltage and temperature of each single cell, and can also control the power and protection functions of the battery pack during the charging and discharging process.

[0050] In other optional examples, the battery pack may further include a protection board, which is used to monitor and control the status and performance of the battery. The protection board generally includes protection circuits such as overcharge protection, discharge protection, short circuit protection, etc.

[0051] An embodiment of the present application further provides a battery cell for a battery pack, the battery cell comprising a housing, a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte.

[0052] The positive electrode and the negative electrode are the main chemical reaction parts of the battery cell. The electrochemically active material of the positive electrode usually contains a compound containing lithium elements, while the negative electrode is usually composed of carbon materials or metal materials.

[0053] The separator is an isolation layer located between the positive electrode and the negative electrode in the battery cell, which prevents direct contact between the positive electrode and the negative electrode, thereby preventing short circuits. The separator is usually configured as a specially formed polymer film.

[0054] The electrolyte is usually a solution that can conduct ions, which is used to provide the movement of positive and negative ions and promote the chemical reactions of the battery cell.

[0055] The positive electrode sheet, negative electrode sheet, separator membrane and electrolyte together constitute the core assembly of the battery cell.

[0056] Depending on the electrolyte, the battery cells include lithium-ion batteries, lithium-sulfur batteries, nano-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries. Depending on whether the electrolyte in the battery cell is replenishable, the battery cells include but are not limited to lithium-ion secondary batteries and lithium-ion primary batteries.

[0057] The housing typically consists of a shell and a top cover assembly. The shell is made of a metal material with a certain degree of mechanical strength and corrosion resistance. Suitable metal materials include nickel or steel. The shell is used to fix and protect the positive and negative electrodes, separator membrane, and electrolyte inside the battery cell from external physical damage. The shell can be wound into a cylindrical shape or configured as a block.

[0058] The top cover assembly is arranged at the top open end of the shell, and the top cover assembly is used to seal the open end of the battery cell and provide a contact point for the positive electrode of the battery cell or a contact point between the positive electrode and the negative electrode of the battery cell.

[0059] In one embodiment of the present application, a structure of a top cover assembly suitable for a battery cell is provided, which is described by taking a square battery cell as an example. FIG1 is a three-dimensional view of the top cover assembly 100, and FIG2 is a cross-sectional view of the top cover assembly 100. The top cover assembly 100 includes an upper plastic part 11, a cover plate 10, and an insulating seat 12 stacked in sequence from top to bottom.

[0060] The cover plate 10 is the primary support member of the top cover assembly 100. It covers the top opening of the housing and supports other components. The cover plate 10 is made of a metal material with good electrical conductivity and mechanical strength. Suitable metal materials for the cover plate 10 include nickel and copper alloys.

[0061] The cover 10 includes an outer surface 101 and an inner surface 102 that are opposite to each other. The upper plastic component 11 is fixed on the outer surface 101 of the cover 10 , and the insulating seat 12 is fixed on the inner surface 102 of the cover 10 .

[0062] Referring to Figures 2 and 3, the top cover assembly 100 also includes a pole 13 and a terminal 14, a first mounting hole is provided on the terminal 14, and the pole 13 is fixed inside the first mounting hole. In one example, the top cover assembly 100 is provided with a first pole 131 and a second pole 132 at intervals, wherein the first pole 131 and the second pole 132 can be positive poles or negative poles with the same polarity. In other optional examples, the first pole 131 and the second pole 132 can be positive poles and negative poles with different polarities.

[0063] The pole 13 and the terminal 14 are fixed by laser welding. The terminal 14 is fixed inside the upper plastic part 11 . A second mounting hole for the pole 13 to pass through is provided on the upper plastic part 11 .

[0064] The cover plate 10 is further provided with a liquid injection hole 15 , which is used for a liquid injection device to replenish electrolyte into the battery cell. The liquid injection hole 15 is located on one side of the upper plastic part 11 .

[0065] Referring to Figures 2 and 3 , the top cover assembly 100 further includes a sealing element 20 and an elastic mechanism 30 . The sealing element 20 is used to seal a portion of the liquid injection hole 15 . One end of the elastic mechanism 30 is connected to the sealing element 20 . The sealing element 20 is configured to move in a first direction relative to the cover plate 10 between a first position and a second position. When the sealing element 20 is in the first position, it seals the liquid injection hole 15 , and the battery cell is in a closed state, preventing the liquid injection device from replenishing electrolyte into the battery cell through the liquid injection hole 15 . When the sealing element 20 is in the second position, the sealing element 20 is offset from the liquid injection hole 15 , allowing the liquid injection device to replenish electrolyte into the battery cell through the liquid injection hole 15 .

[0066] Among them, the driving force for the sealing element 20 to move from the first position to the second position comes from the force of the injection device on the sealing element 20, that is, when the electrolyte needs to be injected, the injection mechanism 60 of the injection device 200 is inserted into the interior of the injection hole 15, and the injection mechanism 60 applies a force to the sealing element 20, so that the sealing element 20 moves from the first position to the second position along the first direction. At the same time, the elastic mechanism 30 connected to the sealing element 20 is compressed. When the electrolyte injection is completed, the injection device 200 is removed. The elastic mechanism 30 has an elastic driving force due to being compressed, and the elastic driving force can drive the sealing element 20 to move from the second position to the first position.

[0067] In a specific implementation, the first direction is configured to be the same as the height direction of the battery cell, and the injection hole 15 is set through the cover plate 10, so as to facilitate the rapid entry of the electrolyte into the interior of the battery cell, wherein the injection device 200 is pressed on one side of the sealing element 20 and has a pressing force along the first direction, and the compressed elastic mechanism 30 is connected to the other side of the sealing element 20 and has an elastic driving force opposite to the first direction.

[0068] In other optional examples, the first direction can also be set along the radial direction of the battery cell, the injection hole 15 can be set on the side of the shell, the injection device 200 is inserted into the injection hole from one side of the battery cell and abuts against one side of the sealing element, and pushes the sealing element to move from the first position to the second position, and the compressed elastic mechanism is connected to the other side of the sealing element 20 and has an elastic driving force opposite to the first direction.

[0069] In the following embodiment, the sealing mechanism of the liquid injection hole 15 is described in detail using the first direction F along the height direction of the battery cell as an example. The insulating seat 12 is connected to the inner surface 102 of the cover plate 10, one end of the elastic mechanism 30 is connected to the sealing element 20, and the other end of the elastic mechanism 30 is connected to the insulating seat 12.

[0070] Referring to Figures 2 and 3, the insulating seat 12 includes a base portion 121 and an extension portion 122, wherein the extension portion 122 is protruding relative to the base portion 121, and the extension portion 122 includes a first cavity 1221. One end of the elastic mechanism 30 is connected to the sealing element 20, and the other end of the elastic mechanism 30 is connected to the bottom wall 123 of the insulating seat 12, and the elastic mechanism 30 is configured to expand and contract along the first direction F inside the first cavity 1221.

[0071] In some embodiments, referring to Figures 12 and 13, a hollow tubular portion 1225 may be further provided inside the first cavity 1221, and the inner cavity of the tubular portion 1225 extends along the first direction F. The sealing element 20 includes a main body portion 21 and a boss portion 22 protruding relative to the main body portion 21, wherein the boss portion 22 is used to seal the injection hole 15, and the main body portion 21 is configured to move inside the tubular portion 1225, so that the sealing element 20 moves along the first direction F and can accurately seal the injection hole 15.

[0072] The first cavity 1221 is connected to the injection hole 15, and the first cavity 1221 is arranged opposite the injection hole 15. The electrolyte flows out through the injection hole 15 and enters the interior of the first cavity 1221. The first cavity 1221 is used to store a certain capacity of electrolyte. The extension portion 122 also includes a plurality of liquid guide holes 124, which can be arranged on the bottom wall 123 of the extension portion 122 or on the side wall of the extension portion 122.

[0073] 2 and 4, the liquid guide hole 124 is provided on the bottom wall 123, and a support platform 1224 is further provided on the bottom wall 123. The support platform 1224 is protruding relative to the other parts of the bottom wall 123, and the elastic mechanism 30 is fixed on the support platform 1224. The plurality of liquid guide holes 124 are provided on the portion outside the support platform 1224. The support platform 1224 is arranged opposite to the sealing element 20, and the area of ​​the support platform 1224 is substantially the same as the area of ​​the sealing element 20. The projection of the sealing element 20 along the first direction is located at The support platform 1224 is positioned opposite the injection hole 15. The electrolyte flowing out of the injection hole 15 flows out through the multiple liquid guide holes 124. The electrolyte flows into the interior of the first cavity 1221 through the injection hole 15 and then flows out through the multiple liquid guide holes 124. Because the multiple liquid guide holes 124 are staggered from the injection hole 15, the portion of the bottom wall where the support platform 1224 is located serves to protect the core assembly inside the battery cell, preventing the electrolyte from flowing directly through the injection hole 15 and forming a strong electrolyte fluid that could damage the core assembly. The electrolyte fluid is dispersed into multiple streams and flows out through the multiple liquid guide holes 124, which effectively reduces the impact force of the electrolyte fluid on the core assembly.

[0074] Referring to Figure 5, the sealing element 20 includes a main body 21 and a boss portion 22 protruding relative to the main body 21, and the cover plate 10 includes an outer surface 101 and an inner surface 102 arranged opposite to each other, wherein the main body 21 abuts against a portion of the inner surface 102, and the boss portion 22 is inserted into the interior of the injection hole 15, so that the sealing element 20 forms a stable sealing effect on the injection hole 15.

[0075] The boss portion 22 is located at the center of the main body portion 21 and includes a top surface 221 and a side surface 222. The top surface 221 is configured as a flat end surface. After the injection mechanism 60 is inserted into the injection hole 15, the injection mechanism 60 abuts against the top surface 221. Positioning the top surface 221 on the end surface of the platform facilitates forming a smooth contact surface between the injection mechanism 60 and the sealing element 20, thereby facilitating the injection mechanism 60 pressing the sealing element 20. The side surface 222 is configured as an arc-shaped transitional curved surface, thereby facilitating the insertion of the boss portion 22 into the injection hole 15.

[0076] As shown in reference figure 3, the injection hole 15 is configured as a stepped hole. Specifically, the injection hole 15 includes a first part 151 and a second part 152 connected to each other, wherein the inner diameter of the first part 151 is larger than the inner diameter of the second part 152, and a step surface 153 is formed between the first part 151 and the second part 152. The boss portion 22 of the sealing element 20 is inserted into the second part 152, wherein the first part 151 is connected to the outside of the battery cell, and the second part 152 is connected to the inside of the battery cell. The boss portion 22 is used to seal the open end of the second part 152. The top cover assembly 100 also includes a sealing sheet 70, which includes an aluminum material. The sealing sheet 70 is covered on the open end of the first part 151 by welding, thereby forming a double-layer sealing effect on the injection hole 15.

[0077] Referring to Figures 6 to 9, in an embodiment provided in the present application, the elastic mechanism 30 is configured as a spring 31, and the spring 31 is configured to extend spirally along a first direction. As shown in Figure 6, one end of the spring 31 abuts against the bottom end of the sealing element 20, and the other end of the spring 31 is connected to the support platform 1224 of the insulating seat 12. As shown in Figures 6 and 7, when the sealing element 20 is in the first position, the spring 31 is in a relaxed state, and one end of the injection mechanism 60 of the injection device 200 is inserted into the injection hole 15. The injection mechanism 60 abuts against the top end surface 221 of the boss portion 22 of the sealing element 20, and the injection mechanism 60 is pressed. The injection mechanism 60 pushes the sealing element 20 to move along the first direction F, and the boss portion 22 of the sealing element is removed from the injection hole 15, and the sealing element 20 compresses the spring 31.

[0078] Continuing to refer to Figures 8 and 9, when the sealing element 20 is in the second position, the spring 31 is in a compressed state. At this time, the sealing element 20 is completely offset from the injection hole 15, and a portion of the injection mechanism 60 is inserted into the interior of the first cavity 1221. The electrolyte enters the interior of the injection hole 15 through the outlet 64 of the injection device 200, enters the interior of the first cavity 1221 through the injection hole 15, and enters the interior of the battery cell through multiple liquid guide holes 124.

[0079] When the sealing element 20 is in the second position, after the injection mechanism 60 is removed from the liquid injection hole 15, the compressed spring 31 generates an elastic force opposite to the first direction, thereby driving the sealing element 20 connected to one end of the spring 31 to move in a direction opposite to the first direction and push the boss portion 22 of the sealing element 20 into the liquid injection hole 15. The main body 21 of the sealing element 20 forms an abutment with the inner surface 102 of the cover plate 10, thereby preventing the elastic driving force of the spring 31 from being too strong and thus pushing the sealing element 20 out of the liquid injection hole 15.

[0080] Referring to Figures 10 and 11 , in another embodiment provided herein, the elastic mechanism 30 is configured as a lantern-shaped elastic member 32. The elastic member 32 includes a plurality of elastic support beams 321 spaced apart from each other. Each elastic support beam 321 is configured as a curved thin sheet structure. The plurality of elastic support beams 321 are symmetrically arranged about the central axis of the elastic member 32. Because adjacent elastic support beams 321 are spaced apart, each elastic support beam 321 can deform freely. One end of the elastic support beam 321 is connected to the bottom end of the sealing element 20, and the other end of the elastic support beam 321 is connected to the bottom wall 123 of the insulating seat 12.

[0081] As shown in Figures 10 and 11, when the sealing element 20 is in the first position, the elastic member 32 is in a relaxed state. One end of the injection mechanism 60 of the injection device 200 is inserted into the injection hole 15. The injection mechanism 60 abuts against the top surface 221 of the boss portion 22 of the sealing element 20. Pressing the injection mechanism 60, the injection mechanism 60 pushes the sealing element 20 to move in the first direction F. The boss portion 22 of the sealing element is removed from the injection hole 15, and the sealing element 20 compresses the elastic member 32. Each support beam 321 of the elastic member 32 is subjected to the downward pressure and bends downward.

[0082] After the injection mechanism 60 is removed from the injection hole 15 , the elastic member 32 in the compressed state generates an elastic force opposite to the first direction, and the elastic member 32 drives the sealing element 20 to move in a direction opposite to the first direction, so that the sealing element 20 seals the injection hole 15 .

[0083] In one embodiment of the present application, a liquid injection device 200 is also provided, which is used to inject electrolyte into the interior of the battery cell, wherein the liquid injection device 200 includes an injection mechanism 60, one end of the injection mechanism 60 is connected to a movable cylinder, and the other end of the injection mechanism 60 is provided with a pressing portion 61, and the pressing portion 61 has an external contour shape that is adapted to the boss portion 22 of the sealing element, so that stable contact is formed between the pressing portion 61 and the boss portion 22.

[0084] The injection mechanism 60 includes a sleeve 62 and a piston 63 that can move relative to the sleeve 62, wherein the piston 63 is open at one end of the sleeve 62, and the other end of the sleeve 62 is provided with a bottom wall. An opening is provided on the bottom wall of the sleeve 62, and the opening is set as the outlet 64 of the injection device 200.

[0085] The sleeve 62 has a hollow inner cavity, a portion of the piston 63 is arranged in the inner cavity of the sleeve 62, and another portion of the piston 63 is arranged outside the sleeve 62, and the outer diameter of the piston 63 is smaller than the inner diameter of the outlet 64 on the sleeve 62, so that the piston 63 can move axially along the sleeve 62 through the outlet 64.

[0086] The piston 63 includes a columnar portion 631 and a base 632 connected to the bottom end of the columnar portion 631 , wherein a portion of the columnar portion 631 is located inside the sleeve 62 , and another portion of the columnar portion 631 extends to the outside of the sleeve 62 through the outlet 64 .

[0087] The outer diameter of the base 632 is larger than the outer diameter of the columnar portion 631, and the base 632 is configured as the pressing portion 61 of the injection mechanism 60. When the cylinder of the injection device 200 is started, the cylinder applies pressing force to one end of the columnar portion 631, and the columnar portion 631 can move downward along the first direction F. The columnar portion 631 and the base 632 are both configured to be inserted into the interior of the injection hole 15. When the base 632 presses on the top surface 221 of the boss portion 22 of the sealing element 20, pressing one end of the columnar portion 631, the base 632 can press the sealing element 20 and thereby drive the sealing element 20 to move downward along the first direction F, wherein the bottom end surface of the sleeve portion 53 abuts against the step surface 153 provided inside the injection hole 15, and a part of the columnar portion 631 and the base 632 are both inserted into the interior of the first cavity 1221 of the insulating seat 12 through the injection hole 15.

[0088] In one embodiment of the present application, a method for injecting electrolyte into a battery cell is further provided. The battery cell includes a top cover assembly 100. The battery cell uses an injection device 200 to inject electrolyte into the interior of the battery cell. The injection method includes:

[0089] Insert the injection mechanism 60 of the injection device 200 into the injection hole 15 and make the injection mechanism 60 abut against one end of the sealing element 20;

[0090] Press the injection mechanism 60, the sealing element 20 moves from the first position to the second position, the injection hole 15 opens, and the injection mechanism 60 injects the electrolyte into the interior of the battery cell through the injection hole 15;

[0091] The injection is stopped, and the injection mechanism 60 is removed from the injection hole 15 . The sealing element 20 is driven by the elastic mechanism 30 to move from the second position to the first position, and the injection hole 15 is closed.

[0092] Before the sealing element 20 moves to the second position, a portion of the columnar portion 631 and base 632 enter the interior of the battery cell through the injection hole 15. An electrolyte outlet is formed between the columnar portion 631 and the bottom outlet 64 of the sleeve 62. The electrolyte enters the injection hole 15 through this outlet and flows into the interior of the battery cell through the injection hole 15. Another portion of the electrolyte flows directly into the interior of the battery cell along the injection portion 501, effectively improving the efficiency of electrolyte introduction.

[0093] The injection mechanism 60 is also equipped with a sensing device that monitors the injection rate of the injection mechanism 60 and controls the injection mechanism 60 to stop injection after the injection time reaches T, where the injection time T = the volume of electrolyte required to be injected into the battery cell / the injection rate of the injection mechanism. By controlling the injection time of the injection mechanism, the volume of the injected electrolyte is precisely controlled to prevent the injected electrolyte from exceeding the storage capacity of the battery cell, thereby causing inaccurate battery cell capacity and affecting the battery cell's use.

[0094] Example 2

[0095] Taking a square battery cell as an example, FIG14 is a three-dimensional view of the top cover assembly 100, and FIG15 to FIG18 are cross-sectional views of the top cover assembly 100. The top cover assembly 100 includes an upper plastic part 11, a cover plate 10, and an insulating seat 12 stacked in sequence from top to bottom.

[0096] The cover plate 10 is the primary support member of the top cover assembly 100. It covers the top opening of the housing and supports other components. The cover plate 10 is made of a metal material with good electrical conductivity and mechanical strength. Suitable metal materials for the cover plate 10 include nickel and copper alloys.

[0097] The cover 10 includes an outer surface 101 and an inner surface 102 that are opposite to each other. The upper plastic component 11 is fixed on the outer surface 101 of the cover 10 , and the insulating seat 12 is fixed on the inner surface 102 of the cover 10 .

[0098] The cover plate 10 is further provided with a liquid injection hole 15 , which is used for a liquid injection device to replenish electrolyte into the battery cell. The liquid injection hole 15 is located on one side of the upper plastic part 11 .

[0099] Referring to Figures 15 to 19 , the top cover assembly 100 further includes a sealing element 20 and an elastic mechanism 30 . The sealing element 20 is used to seal a portion of the liquid injection hole 15 . One end of the elastic mechanism 30 is connected to the sealing element 20 . The sealing element 20 is configured to move in a first direction relative to the cover plate 10 between a first position and a second position. When the sealing element 20 is in the first position, the sealing element 20 can seal the liquid injection hole 15 , the battery cell is in a closed state, and the liquid injection device cannot replenish electrolyte into the interior of the battery cell through the liquid injection hole 15 , as shown in Figures 15 and 3 . When the sealing element 20 is in the second position, the sealing element 20 is offset from the liquid injection hole 15 , and the liquid injection device can replenish electrolyte into the interior of the battery cell through the liquid injection hole 15 , as shown in Figures 17 and 18 .

[0100] Among them, the driving force for the sealing element 20 to move from the first position to the second position comes from the driving force provided by the injection device 200 to the sealing element 20. When the electrolyte injection is completed, the injection device 200 is removed, and the elastic mechanism 30 has an elastic driving force due to compression. This elastic driving force can drive the sealing element 20 to move from the second position to the first position.

[0101] The sealing element 20 includes a main body 21 and a boss portion 22 protruding relative to the main body 21. The cover plate 10 includes an outer surface 101 and an inner surface 102 arranged opposite to each other, wherein the main body 21 abuts against a portion of the inner surface 102, and the boss portion 22 is inserted into the interior of the injection hole 15, so that the sealing element 20 forms a stable sealing effect on the injection hole 15.

[0102] The boss portion 22 is located at the center of the main body portion 21 and includes a top surface 221 and a side surface 222. The top surface 221 is configured as a flat end surface. After the injection mechanism 60 is inserted into the injection hole 15, the pressing portion 61 of the injection mechanism 60 abuts against the top surface 221. Positioning the top surface 221 on the end surface of the platform facilitates forming a smooth contact surface between the injection mechanism 60 and the sealing element 20, thereby facilitating the injection mechanism 60 to press the sealing element 20. The side surface 222 is configured as an arc-shaped transitional curved surface, thereby facilitating the insertion of the boss portion 22 into the injection hole 15.

[0103] Referring to Figures 16 and 18, the injection hole 15 is configured as a stepped hole. Specifically, the injection hole 15 includes a first part 151 and a second part 152 that are connected, wherein the inner diameter of the first part 151 is larger than the inner diameter of the second part 152, and a step surface 153 is formed between the first part 151 and the second part 152. The boss portion 22 of the sealing element 20 is inserted into the second part 152, wherein the first part 151 is connected to the outside of the battery cell, and the second part 152 is connected to the inside of the battery cell, and the boss portion 22 is used to seal the open end of the second part 152.

[0104] Referring to Figures 15 and 16, the top cover assembly 100 of the battery cell to be injected with electrolyte is in the state shown in Figures 15 and 16, the boss portion 22 of the sealing element is inserted into the second part 152 of the injection hole, and the injection mechanism 60 of the injection device 200 is inserted into the injection hole 15. The injection mechanism 60 is pressed until the pressing portion 61 of the injection mechanism 60 contacts the boss portion 22 of the sealing element. The injection mechanism 60 is continued to be pressed, and the sealing element 20 moves downward along the height direction of the battery cell and is completely offset from the injection hole 15.

[0105] Continuing to refer to Figures 17 and 18, when the sealing element 20 moves to the second position, the elastic mechanism 30 is in a compressed state, the sleeve 62 of the injection mechanism abuts against the step surface 153 inside the injection hole 15, and a portion of the piston 63 of the injection mechanism passes through the injection hole 15 into the interior of the battery cell, and the electrolyte enters the interior of the battery cell along the outer wall of the piston.

[0106] When the sealing element 20 is in the second position, the elastic mechanism 30 is in a compressed state. After the injection is completed, the injection mechanism 60 removes the injection hole 15, and the elastic mechanism 30 applies an upward force to the sealing element 20, and the sealing element 20 moves from the second position toward the direction close to the first position.

[0107] During the process of injecting electrolyte into the battery cell, the electrolyte will come into contact with the sealing element 20 and the elastic mechanism 30, wherein the sealing element 20 is made of corrosion-resistant rubber material, and the elastic mechanism 30 is usually an elastic part made of metal material, which includes a spring. The electrolyte usually contains strong acidic or alkaline substances, so a chemical reaction is easily generated between the electrolyte and the elastic mechanism 30 made of metal material, which can easily cause the electrolyte to be contaminated on the one hand, and on the other hand, it can easily cause the elastic mechanism 30 to be corroded by the electrolyte, thereby damaging the elastic mechanism 30.

[0108] Referring to Figures 19 to 29, in one embodiment of the present application, the top cover assembly 100 also includes a sealing sleeve 50, which is configured to be arranged around the elastic mechanism 30. The elastic mechanism 30 is configured to expand and contract inside the sealing sleeve 50, so that the elastic mechanism 30 is provided with a cover sealing sleeve 50 structure, so that the electrolyte is difficult to contact the elastic mechanism 30, thereby effectively preventing the elastic mechanism 30 from being corroded by the electrolyte.

[0109] In an example provided in the present application, the sealing sleeve 50 is made of a corrosion-resistant rubber material to form a sleeve-shaped structure, the elastic mechanism 30 is arranged inside the sealing sleeve 50, and the sealing element 20 is configured to be accommodated inside the sealing sleeve 50, and the sealing element 20 is configured to be able to move inside the sealing sleeve 50. During the movement of the sealing element 20, the outer wall of the sealing element 20 is always sealed and connected to the inner wall of the sealing sleeve 50. Therefore, during the movement of the sealing element 20, even if a part of the electrolyte enters the interior of the sealing sleeve 50 through the open end of the sealing sleeve 50, the sealing element 20 can prevent a part of the electrolyte entering the interior of the sealing sleeve 50 from contacting the elastic mechanism 30.

[0110] Specifically, when the sealing element 20 moves downward, the elastic mechanism 30 is compressed, and the sealing element 20 and the sealing sleeve 50 are sealed and connected. The sealing element 20 shields the elastic mechanism 30, thereby preventing the electrolyte from contacting the elastic mechanism 30.

[0111] When the sealing element 20 is elastically driven by the elastic mechanism 30 and moves upward, the sealing element 20 blocks the elastic mechanism 30 and simultaneously guides a portion of the electrolyte to the outside of the sealing sleeve 50, thereby effectively preventing the electrolyte from contacting the elastic mechanism 30.

[0112] The elastic mechanism 30 is connected to one end of the sealing element 20, and the other end of the sealing element 20 is in a free state. During the free rebound process of the elastic mechanism 30, the force exerted by the elastic mechanism 30 on the sealing element 20 may cause inclination, thereby causing the sealing element 20 to be unable to accurately seal the liquid injection hole 15, thereby causing the top cover assembly 100 to be unable to seal.

[0113] A guide device 40 is also provided inside the top cover assembly 100, and the guide device 40 is provided with a hollow second cavity 41, and the second cavity 41 defines a guide channel 42. The sealing element 20 includes a guide portion 23, and the guide portion 23 is configured to move inside the guide channel 42, wherein the guide channel 42 extends along a first direction, thereby guiding the guide portion 23 of the sealing element to move along the first direction and thereby causing the sealing element 20 to move along the first direction from the second position to the first position, thereby being able to accurately seal the injection hole.

[0114] In one embodiment, the sealing element 20 moves substantially along the height direction of the battery cell. Since the guide channel 42 extends along the same direction as the moving path of the sealing element 20 , the guide channel 42 is arranged along the same direction as the height direction of the battery cell.

[0115] 22 to 29 , the elastic mechanism 30 and the sealing sleeve 50 are both disposed within the second cavity 41, with the elastic mechanism 30 configured to move axially along the guide 40. The guide 40 is made of a hard plastic or rubber material, while the sealing sleeve 50 is made of a flexible fiber cotton material. The sealing sleeve 50 can be formed into a sleeve-like body made of a polymer fiber cotton material, or it can be formed into a sheet-like body made of a fiber cotton material. The sheet-like body is wound within the second cavity 41, forming a seal between the outer surface of the sealing sleeve 50 and the inner surface of the second cavity 41, thereby preventing the electrolyte from entering the interior of the second cavity 41.

[0116] The sealing element 20 is accommodated in the second cavity 41 , and the sealing sleeve 50 is coaxially arranged with the sealing element 20 . The sealing sleeve 50 is located at the periphery of the sealing element 20 , and a sealing connection is formed between the outer wall of the sealing element 20 and the inner surface of the sealing sleeve 50 .

[0117] The friction coefficient between the sealing element 20 and the sealing sleeve 50 is the same as the friction coefficient between the sealing sleeve 50 and the guide device 40 , so that the sealing sleeve 50 remains fixed inside the second cavity 41 during the movement of the sealing element 20 inside the sealing sleeve 50 .

[0118] The guide device 40 includes a plurality of cylindrical portions 44, and the sealing element 20 includes a plurality of guide portions 23. The plurality of guide portions 23 are connected to the outer periphery of the main body 21. An elastic mechanism 30 is provided inside each cylindrical portion 44. A sealing sleeve 50 is also provided inside each cylindrical portion 44. The outer surface of the sealing sleeve 50 is sealed with the inner surface of the cylindrical portion 44. A guide portion 23 can be accommodated inside each cylindrical portion 44, and the guide portion 23 is provided inside the sealing sleeve 50.

[0119] The guide portion 23 , the sealing sleeve 50 and the cylindrical portion 44 are coaxially arranged, and both the sealing sleeve 50 and the cylindrical portion 44 extend along the first direction. The sealing sleeve 50 and the cylindrical portion 44 have the same extension height.

[0120] 22 to 29, the guide device 40 includes a first cylindrical portion 441, a second cylindrical portion 442, and a third cylindrical portion 443. A first elastic mechanism 331 is provided inside the first cylindrical portion 441. A first sealing sleeve 51 is also provided inside the first cylindrical portion 441. The first sealing sleeve 51 is configured to be provided around the first elastic mechanism 331. The first elastic mechanism 331 is configured to move in the inner cavity of the first sealing sleeve 51. A second elastic mechanism 332 is provided inside the second cylindrical portion 442. A second sealing sleeve 52 is also provided inside the second cylindrical portion 442, and the second sealing sleeve 52 is constructed to be arranged around the second elastic mechanism 332, and the second elastic mechanism 332 is configured to move in the inner cavity of the second sealing sleeve 52. A third elastic mechanism 333 is provided inside the third cylindrical portion 443, and a third sealing sleeve 53 is also provided inside the third cylindrical portion 443, and the third sealing sleeve 53 is constructed to be arranged around the third elastic mechanism 333, and the third elastic mechanism 333 is configured to move in the inner cavity of the third sealing sleeve 53.

[0121] 21 , the sealing element 20 includes a first guide portion 231 , a second guide portion 232 and a third guide portion 233 , wherein the first guide portion 231 , the second guide portion 232 and the third guide portion 233 are evenly spaced and arranged on the periphery of the main body 21 .

[0122] The first elastic mechanism 331 is connected to the first guide portion 231, and the first guide portion 231 is configured to move inside the first cylindrical portion 441. The second elastic mechanism 332 is connected to the second guide portion 232, and the second guide portion 232 is configured to move inside the second cylindrical portion 442. The third elastic mechanism 333 is connected to the third guide portion 233, and the third guide portion 233 is configured to move inside the third cylindrical portion 443.

[0123] The first elastic mechanism 331, the second elastic mechanism 332 and the third elastic mechanism 333 simultaneously provide elastic support and elastic driving force to the first guide portion 231, the second guide portion 232 and the third guide portion 233 of the sealing element, so that the sealing element 20 can be stably maintained inside the top cover assembly 100. At the same time, during the movement of the sealing element 20, the three cylindrical portions 44 are provided to guide its moving direction and moving position, so that the moving direction and moving position of the sealing element 20 are more stable and precise, which is conducive to the sealing element 20 to more accurately seal the injection hole 15.

[0124] The sealing element 20 also includes a connecting portion 24 for connecting the guide portion 23 and the main body portion 21. Specifically, when three guide portions 23 are provided on the sealing element 20, the sealing element 20 includes a first connecting portion 241, a second connecting portion 242 and a third connecting portion 243, wherein the first connecting portion 241 is used to connect the first guide portion 231 and the main body portion 21, the second connecting portion 242 is used to connect the second guide portion 232 and the main body portion 21, and the third connecting portion 243 is used to connect the third guide portion 233 and the main body portion 21.

[0125] The cross sections of the main body 21 and the three guide parts 23 are all circular, and the outer diameter of the guide part 23 is smaller than the outer diameter of the main body 21 .

[0126] As shown in Reference Figure 29, an opening 45 is also provided on the side wall of each cylindrical portion 44. The opening 45 extends along the first direction and passes through the side wall of the cylindrical portion 44. When the sealing element 20 moves, the guide portion 23 moves inside the cylindrical portion 44, the main body portion 21 moves outside the cylindrical portion 44, and the connecting portion 24 moves along the opening 45.

[0127] The sealing sleeve 50 includes a main body portion 501 and an extension portion 502, wherein the main body portion 501 is arranged inside the cylindrical portion 44, the extension portion 502 is arranged in the opening 45, and the connecting portion 24 of the sealing element abuts against the top of the extension portion 502. During the movement of the sealing element 20, the main body portion 501 of the sealing sleeve 50 can be fixed inside the cylindrical portion 44, and the main body portion 501 of the sealing sleeve 50 can also move with the sealing element 20, while the extension portion 502 is pressed by the connecting portion 24 and moves with the sealing element 20.

[0128] The extension portion 502 is used to seal the opening 45 , thereby preventing the electrolyte from entering the interior of the sealing sleeve 50 through the opening 45 .

[0129] The sealing element 20 is provided with a first guide portion 231, a second guide portion 232 and a third guide portion 233, wherein the angle between the first guide portion 231 and the second guide portion 232 is set to 120 degrees, the angle between the second guide portion 232 and the third guide portion 233 is set to 120 degrees, and the angle between the third guide portion 233 and the first guide portion 231 is set to 120 degrees.

[0130] In other alternative examples, a plurality of guide portions 23 may be provided on the sealing element 20, and the number of the guide portions 23 may be 2, 4, 6, or more, thereby facilitating smoother movement of the sealing element 20 under the guidance of the plurality of guide portions 23. Correspondingly, the number of the cylindrical portions 44 provided on the guide device 40 remains the same as the number of the guide portions 23.

[0131] The insulating base 12 is provided with a first cavity 1221 , which is protruding relative to the main body of the insulating base 12 . The insulating base 12 includes side walls 126 and a bottom wall 123 defining the first cavity 1221 . The guide device 40 is provided inside the first cavity 1221 .

[0132] The bottom wall 123 includes a first portion of the bottom wall 1231 and a second portion of the bottom wall 1232, wherein the first portion of the bottom wall 1231 is provided with a plurality of liquid guide holes 124, and the guide device 40 is provided on the second portion of the bottom wall 1232. When the guide device 40 includes a plurality of cylindrical portions 44, the plurality of cylindrical portions 44 are arranged at intervals on the second portion of the bottom wall 1232, and no liquid guide holes 124 are provided on the portion of the bottom wall between the plurality of cylindrical portions 44.

[0133] The electrolyte enters the first cavity 1221 through the injection hole 15, and enters the interior of the battery cell through multiple liquid guide holes 124. The second part of the bottom wall 1232 is arranged opposite the sealing element 20, and the sealing element 20 is arranged opposite the injection hole 15. After the electrolyte enters the first cavity 1221 through the injection hole 15, the multiple liquid guide holes 124 are used to guide the electrolyte to flow out in a dispersed manner, thereby preventing the electrolyte from directly flowing out through the injection hole 15, forming a strong fluid impact force and damaging the core assembly inside the battery cell.

Claims

1. A top cover assembly (100), the top cover assembly (100) being arranged on a battery cell, the top cover assembly (100) comprising: Cover plate (10); A liquid injection hole (15) is provided on the cover plate (10), and the liquid injection hole (15) is provided for injecting electrolyte into the battery cell; a sealing element (20), the sealing element (20) being configured to be movable along a first direction between a first position and a second position relative to the cover plate (10); when the sealing element (20) is in the first position, the sealing element (20) is capable of sealing the liquid injection hole (15); and when the sealing element (20) is in the second position, the sealing element (20) is offset from the liquid injection hole (15); An elastic mechanism (30), one end of the elastic mechanism (30) being connected to the sealing element (20), the elastic mechanism (30) being configured to be capable of being extended and retracted along a first direction; when the sealing element (20) is in a first position, the elastic mechanism (30) is used to support the sealing element (20); when the sealing element (20) is in a second position, the elastic mechanism (30) is in a compressed state to have elastic potential energy to drive the sealing element (20) to move from the second position to the first position.

2. The top cover assembly (100) according to claim 1, wherein: The top cover assembly (100) further comprises an insulating seat (12) connected to one side of the cover plate (10), and the other end of the elastic mechanism (30) is connected to the insulating seat (12).

3. The top cover assembly (100) according to claim 2, wherein: The insulating seat (12) comprises a base portion (121) and an extension portion (122) protruding relative to the base portion (121), the extension portion (122) being provided with a first cavity (1221), and the elastic mechanism (30) being configured to extend and retract along the first direction inside the first cavity (1221).

4. The top cover assembly (100) according to claim 3, wherein: The insulating seat (12) further comprises a cylindrical portion (1225) arranged inside the first cavity (1221); the sealing element (20) comprises a main body portion (21) and a boss portion (22) protruding relative to the main body portion (21); the main body portion (21) is configured to move inside the cylindrical portion (1225); and the boss portion (22) is configured to seal the injection hole (15).

5. The top cover assembly (100) according to claim 3, wherein: The extension portion (122) comprises a bottom wall (123) defining the bottom of the first cavity (1221), the bottom wall (123) comprises a support platform (1224), the support platform (1224) is arranged opposite to the sealing element (20), and the elastic mechanism (30) is fixed on the support platform (1224).

6. The top cover assembly (100) according to claim 1, wherein: The sealing element (20) comprises a main body portion (21) and a boss portion (22) protruding relative to the main body portion (21), wherein the boss portion (22) is configured to seal the liquid injection hole (15); The cover plate (10) comprises an outer surface (101) and an inner surface (102) which are arranged opposite to each other, and the main body (21) abuts against a portion of the inner surface (102).

7. The top cover assembly (100) according to claim 6, wherein: The boss portion (22) has a flat top end surface (221), and the top end surface (221) is configured to abut against the liquid injection device (200).

8. The top cover assembly (100) according to claim 6, wherein: The top cover assembly (100) further comprises a sealing sheet (70), wherein the sealing sheet (70) is configured to seal an opening at one end of the liquid injection hole (15) away from the elastic mechanism (30), and the boss portion (22) is configured to seal an opening at one end of the liquid injection hole (15) close to the elastic mechanism (30).

9. The top cover assembly (100) according to any one of claims 1 to 8, wherein: The elastic mechanism (30) comprises a spring (31), and the spring (31) is configured to extend helically along the first direction; Alternatively, the elastic mechanism (30) comprises a plurality of elastic support beams (321), the plurality of elastic support beams (321) are arranged at intervals, and each of the elastic support beams (321) is configured to be able to bend.

10. The top cover assembly (100) according to claim 1, further comprising: The sealing sleeve (50) is configured to be arranged around the elastic mechanism (30), and the elastic mechanism (30) is configured to expand and contract inside the sealing sleeve (50), thereby preventing the electrolyte from contacting the elastic mechanism (30).

11. The top cover assembly (100) according to claim 10, wherein: The sealing element (20) comprises a main body (21), wherein the main body (21) is configured to move inside the sealing sleeve (50), and an outer wall of the main body (21) is configured to be sealingly connected to an inner wall of the sealing sleeve (50).

12. The top cover assembly (100) according to claim 10, wherein: The sealing element (20) comprises a main body (21) and at least one guide portion (23) connected to the main body (21); the guide portion (23) is configured to be movable inside the sealing sleeve (50); and an outer wall of the guide portion (23) is configured to be sealingly connected to an inner wall of the sealing sleeve (50).

13. The top cover assembly (100) according to claim 10, wherein: The top cover assembly (100) further comprises a guide device (40), the guide device (40) being provided with a second cavity (41), and the sealing sleeve (50) being arranged inside the second cavity (41).

14. The top cover assembly (100) according to claim 13, wherein: The top cover assembly (100) comprises an insulating seat (12), the guide device (40) is coupled to the insulating seat (12), the insulating seat is provided with a first cavity (1221), and the guide device (40) is arranged inside the first cavity (1221).

15. The top cover assembly (100) according to claim 14, wherein: The sealing element (20) comprises a main body (21) and a plurality of guide portions (23) connected to the main body (21); the guide device (40) comprises a plurality of cylindrical portions (44); each cylindrical portion (44) is provided with an elastic mechanism (30) and at least one sealing sleeve (50) inside; each cylindrical portion (44) is provided with a guide channel (42) for allowing one of the guide portions (23) to move.

16. The top cover assembly (100) according to claim 15, wherein: The sealing sleeve (50) is coaxially arranged with the guide portion (23).

17. The top cover assembly (100) according to claim 15, wherein: The sealing element (20) further comprises a plurality of connecting portions (24), and the guide portion (23) is connected to the main body portion (21) via the connecting portions (24); The cylindrical portion (44) is provided with an opening (45), the opening (45) is provided on a side wall of the cylindrical portion (44) and extends along the first direction, and the opening (45) is configured to allow the connecting portion (24) to move.

18. The top cover assembly (100) according to claim 17, wherein: The sealing sleeve (50) comprises a main body portion (501) and an extension portion (502), wherein the main body portion (501) is arranged inside the cylindrical portion (44), the extension portion (502) is arranged inside the opening (45), and the connecting portion (24) is arranged at one end of the extension portion (502).

19. The top cover assembly (100) according to claim 18, wherein: The guide portion (23) of the sealing element (20) comprises a first guide portion (231), a second guide portion (232) and a third guide portion (233) which are arranged at intervals, and the first guide portion (231), the second guide portion (232) and the third guide portion (233) are connected to the outer periphery of the main body portion (21) at even intervals.

20. The top cover assembly (100) according to claim 19, wherein: The cylindrical portion (44) of the guide device (40) comprises a first cylindrical portion (441), a second cylindrical portion (442) and a third cylindrical portion (443) which are arranged at intervals; A first elastic mechanism (331) and a first sealing sleeve (51) arranged around the first elastic mechanism (331) are arranged inside the first cylindrical portion (441), and the first guide portion (231) moves inside the first sealing sleeve (51). A second elastic mechanism (332) and a second sealing sleeve (52) arranged around the second elastic mechanism (332) are arranged inside the second cylindrical portion (442), and the second guide portion (232) moves inside the second sealing sleeve (52). A third elastic mechanism (333) and a third sealing sleeve (53) arranged around the third elastic mechanism (333) are arranged inside the third cylindrical portion (443), and the third guide portion (233) moves inside the third sealing sleeve (53).

21. The top cover assembly (100) according to claim 20, wherein: The insulating seat (12) comprises a bottom wall (123) defining the bottom of the first cavity (1221), the bottom wall (123) comprising a first portion bottom wall (1231) and a second portion bottom wall (1232), wherein the first portion bottom wall (123) is provided with a plurality of liquid guide holes (124), and the first cylindrical portion (441), the second cylindrical portion (442) and the third cylindrical portion (443) are provided on the second portion bottom wall (1232).

22. A battery pack, comprising a plurality of battery cells, wherein the battery cells comprise the top cover assembly (100) according to any one of claims 1 to 21.

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