Top cover assembly, liquid injection method for battery cell, and battery pack

Abstract

The present application provides a top cover assembly, a liquid injection method for a battery cell, and a battery pack. The top cover assembly comprises a cover plate; a liquid injection hole which is formed in the cover plate; a sealing element configured to move between a first position and a second position with respect to the cover plate; a driving mechanism, used for driving the sealing element; and a guide device, the guide device being provided with a guide channel, and at least part of the sealing element being configured to move in the guide channel.

Description

Top cover assembly, battery cell injection method, and battery pack

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on November 2, 2023, with application number 202311455881.1. The entire contents of the above application 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, a method for injecting liquid into a battery cell, and a battery pack. Background Art

[0003] A battery pack includes multiple battery cells, each of which includes 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 in multiple times or some battery packs are configured so that the electrolyte is replenishable. Removing the sealing gasket and sealing particles used to seal the injection hole is often complicated, especially the sealing particles require the use of tools and are difficult to operate.

[0004] To address the above problems, related technologies have adopted a method of providing a reciprocating sealing element in the top cover assembly to facilitate replenishment of the electrolyte inside the battery cell. However, after the injection operation is completed, the rebound position and direction of the sealing element cannot be accurately positioned, which may easily lead to the problem that the sealing element cannot accurately seal the injection hole. SUMMARY OF THE INVENTION

[0005] The embodiments of the present application provide a top cover assembly, a method for injecting liquid into a battery cell, and a battery pack, which can solve the problem that the sealing element cannot accurately seal the injection hole.

[0006] In a first aspect, an embodiment of the present application provides a top cover assembly, wherein the top cover assembly is disposed on a battery cell, and the top cover assembly includes:

[0007] cover;

[0008] A liquid injection hole is provided on the cover plate, and the liquid injection hole is used to replenish the electrolyte into the interior of the battery cell;

[0009] 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;

[0010] a driving mechanism, the driving mechanism being configured to drive the sealing element to move from the second position to the first position;

[0011] A guide device is provided with a guide channel, which extends along the first direction. At least a portion of the sealing element is configured to move in the guide channel, so that at least a portion of the sealing element moves to the interior of the injection hole and seals the injection hole under the drive of the driving mechanism.

[0012] In a second aspect, an embodiment of the present application provides a method for injecting electrolyte into a battery cell, wherein the battery cell includes the above-mentioned top cover assembly, and the battery cell uses an injection device to inject electrolyte into the interior of the battery cell, wherein the injection device includes an injection mechanism, and the injection method includes:

[0013] Inserting the injection mechanism of the liquid injection device into the liquid injection hole, and making the injection mechanism abut against one end of the sealing element;

[0014] Pressing the injection mechanism, the sealing element is driven by the injection mechanism to move from the first position to the second position along the guide channel, the injection hole is opened, and the injection mechanism injects the electrolyte into the interior of the battery cell through the injection hole;

[0015] The injection is stopped, the injection mechanism is removed from the injection hole, and the sealing element is driven by the elastic mechanism to move from the second position to the first position along the guide channel, and the injection hole is closed.

[0016] In a third aspect, an embodiment of the present application provides a battery pack, which includes a plurality of battery cells, the battery cells having the above-mentioned top cover assembly, or the battery cells having electrolyte injected therein using the above-mentioned injection method. Beneficial effects

[0017] The beneficial effects of this application are:

[0018] In an embodiment of the present application, a sealing element, a driving mechanism and a guide device are arranged in the top cover assembly, and the guide device is provided with a guide channel, which is used to guide the movement of the sealing element. The guide channel extends along a first direction, so that the sealing element extends along the first direction, so that after the injection operation is completed, the sealing element moves along the guide channel defined by the guide device under the driving action of the driving mechanism, so that the injection hole can be accurately sealed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG1 is a perspective view of a top cover assembly provided in an embodiment of the present application;

[0020] FIG2 is a cross-sectional view of the top cover assembly when the sealing element provided in an embodiment of the present application is in a first position;

[0021] FIG3 is a partial enlarged view of FIG2;

[0022] 4 is a cross-sectional view of the top cover assembly when the sealing element provided in an embodiment of the present application is in a second position;

[0023] FIG5 is a partial enlarged view of FIG4;

[0024] FIG6 is a perspective view of a sealing element provided in an embodiment of the present application;

[0025] FIG7 is a schematic structural diagram of a liquid injection device provided in an embodiment of the present application;

[0026] FIG8 is a structural diagram of an injection mechanism provided in an embodiment of the present application;

[0027] FIG9 is a cross-sectional view of a top cover assembly provided in accordance with another embodiment of the present application;

[0028] FIG10 is a partial enlarged view of FIG9;

[0029] FIG11 is a perspective view of a guide device provided by one embodiment of the present application;

[0030] FIG12 is a cross-sectional view of a top cover assembly provided by one embodiment of the present application;

[0031] FIG13 is a partial enlarged view of FIG12;

[0032] FIG14 is a perspective view of a guide device provided in yet another embodiment of the present application;

[0033] FIG15 is a cross-sectional view of a top cover assembly provided in accordance with another embodiment of the present application;

[0034] FIG16 is a partial enlarged view of FIG15;

[0035] FIG17 is a perspective view of a guide device provided in another embodiment of the present application;

[0036] FIG18 is a partial enlarged view of FIG17;

[0037] FIG19 is a perspective view of a battery pack according to an embodiment of the present application;

[0038] Figure Number:

[0039] 10000, battery pack; 2000, box;

[0040] 1000, battery cell;

[0041] 100. Top cover assembly;

[0042] 10. Cover plate; 101. Outer surface; 102. Inner surface; 11. Upper plastic part;

[0043] 12. Insulating seat; 121. Second cavity; 122. First side wall; 123. First bottom wall; 124. Support platform; 125. Second liquid guide hole; 126. Blocking wall; 13. Liquid injection hole; 131. First portion; 132. Second portion; 133. Step surface; 14. Sealing sheet;

[0044] 20. Sealing element; 21. Main body; 22. Boss; 221. Top end surface; 222. Side surface; 23. Guide portion;

[0045] 30. Elastic mechanism;

[0046] 40. Guide device; 41. First cavity; 42. Guide channel; 43. Second side wall; 44. First cylindrical portion; 441. First flange; 45. Second cylindrical portion; 46. First liquid guide hole; 47. Cylindrical portion;

[0047] 200. Liquid injection device;

[0048] 50. Base; 51. Support frame; 52. Top frame; 53. Cylinder; 54. Pressure rod; 55. Vacuum system;

[0049] 60. Injection mechanism; 61. Pressing portion; 62. Sleeve; 621. Inner cavity; 622. Second bottom wall; 623. Opening; 63. Piston; 631. Base; 6311. Bottom end surface; 632. Columnar portion;

[0050] 70. Sealing sleeve. Modes for Carrying Out the Invention

[0051] In this application, unless otherwise specified, directional words such as "upper" and "lower" generally refer to the upper and lower parts of the device in actual use or working state, specifically the direction of the drawings in the accompanying drawings; while "inside" and "outside" refer to the outline of the device.

[0052] One embodiment of the present application provides a battery pack 10000, which includes one or more single battery cells 1000. The multiple single battery cells 1000 can be arranged to be connected in series, or the multiple single battery cells 1000 can be arranged to be connected in parallel, or the multiple single battery cells 1000 can be arranged to be a mixed connection of series and parallel, so that the battery pack 10000 has a capacity and power suitable for use by electrical equipment.

[0053] The battery pack 10000 also includes a connecting piece, which is used to connect the multiple single battery cells 1000 so that the positive and negative electrodes of the multiple single battery cells 1000 have a stable series-parallel connection structure. Materials suitable for preparing the connecting piece include copper foil.

[0054] The battery pack 10000 also includes a box 2000, as shown in Figure 19. The box 2000 is used to fix and protect multiple single battery cells 1000 and other components. The box 2000 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.

[0055] The battery pack 10000 is applicable to electrical devices including mobile phones, portable devices, laptop computers, electric bicycles, electric cars, electric boats, electric toys, electric tools, etc.

[0056] Depending on the safety performance requirements and space requirements of the applicable electrical equipment, the battery pack 10000 may also include a BMS (battery management system), which is used to monitor, protect and manage the working status of the battery pack 10000. The BMS can monitor and balance the voltage and temperature of each single cell 1000, and can also control the power and protection functions of the battery pack 10000 during the charging and discharging process.

[0057] In other optional examples, the battery pack 10000 may also include a protection board, which is used to monitor and control the status and performance of the battery. The protection board usually includes protection circuits such as overcharge protection, discharge protection, short circuit protection, etc.

[0058] An embodiment of the present application further provides a battery cell 1000 for the above-mentioned battery pack 10000 , wherein the battery cell 1000 includes a housing, a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte.

[0059] The positive electrode sheet and the negative electrode sheet are the main chemical reaction parts of the battery cell 1000. The electrochemically active material of the positive electrode sheet usually contains a compound containing lithium elements, and the negative electrode sheet usually contains carbon materials or metal materials.

[0060] The separator is an isolation layer located between the positive electrode and the negative electrode in the battery cell 1000, so that the positive electrode and the negative electrode do not directly contact each other, thereby preventing the occurrence of short circuits. The separator is usually configured as a specially formed polymer film.

[0061] The electrolyte is generally a solution that can conduct ions and is used to provide movement of positive and negative ions and promote chemical reactions in the battery cell 1000.

[0062] The positive electrode sheet, negative electrode sheet, separator and electrolyte together constitute the core assembly of the battery cell 1000 .

[0063] Depending on the electrolyte, the battery cell 1000 includes a lithium-ion battery, a lithium-sulfur battery, a nano-lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery. Depending on whether the electrolyte in the battery cell 1000 is replenishable, the battery cell 1000 includes but is not limited to a lithium-ion secondary battery or a lithium-ion primary battery.

[0064] The housing typically consists of a shell and a top cover assembly. The shell is made of a metal material with sufficient mechanical strength and corrosion resistance, such as nickel or steel. It secures and protects the positive and negative electrodes, separator, and electrolyte within the battery cell 1000 from external physical damage. The shell can be wound into a cylindrical shape or configured as a block.

[0065] The top cover assembly is disposed at the top open end of the shell, and the top cover assembly is used to seal the open end of the battery cell 1000 and provide a contact point for the positive electrode of the battery cell 1000 or a contact point between the positive electrode and the negative electrode of the battery cell 1000 .

[0066] In one embodiment of the present application, a structure of a top cover assembly suitable for the above-mentioned battery cell 1000 is provided, and a square battery cell 1000 is taken as an example for explanation. Reference FIG1 is a three-dimensional view of the top cover assembly 100, and FIG2 to FIG5 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.

[0067] 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.

[0068] 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 .

[0069] The cover plate 10 is further provided with a liquid injection hole 13 , which is used for a liquid injection device to replenish electrolyte into the battery cell 1000 . The liquid injection hole 13 is located on one side of the upper plastic part 11 .

[0070] With further reference to Figures 2 to 6 , the top cover assembly 100 further includes a sealing element 20 and a driving mechanism, wherein the sealing element 20 is used to seal a portion of the liquid injection hole 13, and one end of the driving mechanism is connected to the sealing element 20, wherein the sealing element 20 is configured to be movable along a first direction between a first position and a second position relative to the cover plate 10, wherein the first direction is the same as the F direction shown in Figure 2 or 3 . When the sealing element 20 is in the first position, the sealing element 20 can seal the liquid injection hole 13, the battery cell 1000 is in a closed state, and the liquid injection device cannot replenish the electrolyte to the interior of the battery cell 1000 through the liquid injection hole 13, as shown in Figures 2 and 3 .

[0071] When the sealing element 20 is in the second position, the sealing element 20 is staggered with the liquid injection hole 13 , and the liquid injection device can replenish the electrolyte into the battery cell 1000 through the liquid injection hole 13 , as shown in FIG. 4 and FIG. 5 .

[0072] 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 driving structure can drive the sealing element 20 to move from the second position to the first position.

[0073] In one embodiment provided in the present application, the driving mechanism is configured as an elastic mechanism 30. When the sealing element 20 is in the second position, the elastic mechanism 30 is compressed and thus has elastic potential energy, which can drive the sealing element 20 to move from the second position to the first position.

[0074] With further reference to Figures 7 and 8, in one embodiment provided in the present application, the liquid injection device 200 includes a base 50, a support frame 51 and a top frame 52, wherein one end of the support frame 51 is fixed to the base 50, and the other end of the support frame 51 is fixed to the top frame 52, and the support frame 51 and the base 50 are arranged to be vertically connected, and the support frame 51 and the top frame 52 are arranged to be vertically connected.

[0075] The battery cell 1000 that needs to be injected with electrolyte is fixed on the base 50 . A plurality of fixing grooves may be provided on the base 50 , and each fixing groove may be used to fix one battery cell 1000 .

[0076] The liquid injection device 200 further includes a cylinder 53, which is suspended on a top frame 52. One end of the cylinder 53 is connected to a pressure rod 54, and the end of the pressure rod 54 facing away from the cylinder 53 is connected to an injection mechanism 60.

[0077] The liquid injection device 200 further includes a vacuum system 55 , which is connected to the cylinder 53 .

[0078] When the battery cell 1000 needs to be injected with electrolyte, the battery cell 1000 is fixed on the base 50, the vacuum system 55 is turned on, the cylinder 53 starts working, the pressure rod 54 connected to the cylinder 53 moves toward the direction close to the battery cell 1000, and the injection mechanism 60 is configured to move toward the injection hole 13.

[0079] One end of the injection mechanism 60 is connected to the pressure rod 54, and the other end of the injection mechanism 60 is provided with a pressing portion 61. When the pressure rod 54 moves toward the direction close to the battery cell 1000, the pressing portion 61 is configured to be inserted into the interior of the injection hole 13 and the pressing portion 61 can also be used to drive the sealing element 20 to move along the first direction so that the sealing element 20 is staggered with the injection hole 13.

[0080] The injection mechanism 60 includes a sleeve 62, which has a hollow inner cavity 621. The top end of the sleeve 62 is configured as an open end, and the bottom end of the sleeve 62 is provided with a second bottom wall 622. An opening 623 is provided on the second bottom wall 622 of the sleeve. The electrolyte can be injected into the first cavity 211 through the open end and flow out through the opening 623.

[0081] The injection mechanism 60 further includes a piston 63 . A portion of the piston 63 extends inside the sleeve 62 , and another portion of the piston 63 extends to the outside of the sleeve 62 through the opening 623 . The piston 63 is movable relative to the sleeve 62 .

[0082] The piston 63 further includes a base 631 , which is disposed outside the sleeve 62 . The base 631 is configured as the pressing portion 61 of the injection mechanism 60 .

[0083] The bottom end surface 6311 of the base 631 is used to form a stable contact with the top end surface of the sealing element 20. Therefore, the bottom end surface 6311 of the base and the top end surface of the sealing element 20 have a basically matching contour shape, which is conducive to forming a stable contact between the base 631 and the sealing element 20.

[0084] The piston 63 further includes a columnar portion 632 connected to one end of the base 631, wherein a portion of the columnar portion 632 is disposed inside the sleeve 62, and another portion of the columnar portion 632 extends outside the sleeve 62. The columnar portion 632 and the base 631 may be integrally formed, or the base 631 may be fixed to one end of the columnar portion 632 by a snap-fit ​​connection or a threaded connection.

[0085] The outer diameter of the base 631 is greater than the outer diameter of the columnar portion 632 , and the base 631 is configured as the pressing portion 61 of the injection mechanism 60 , thereby facilitating formation of a stable contact surface between the pressing portion 61 and the boss portion of the sealing element.

[0086] Furthermore, 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 13, so that the sealing element 20 forms a stable sealing effect on the injection hole 13.

[0087] 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 13, 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 13.

[0088] Further referring to Figure 5, the injection hole 13 is configured as a stepped hole. Specifically, the injection hole 13 includes a first part 131 and a second part 132 connected to each other, wherein the inner diameter of the first part 131 is larger than the inner diameter of the second part 152, and a step surface 133 is formed between the first part 131 and the second part 132. The boss portion 22 of the sealing element 20 is inserted into the second part 132, wherein the first part 131 is connected to the outside of the battery cell, and the second part 132 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 132.

[0089] The top cover assembly 100 also includes a sealing sheet 14 made of aluminum. The sealing sheet 14 is welded to the open end of the first portion 131, thereby forming a double seal for the injection hole 13. When electrolyte needs to be injected, the sealing sheet 14 can be removed from the open end of the first portion 131. After injection is complete, the sealing sheet 14 can be re-welded to the open end of the first portion 131.

[0090] With further reference to Figures 2 and 3, the top cover assembly 100 of the battery cell to be injected with electrolyte is in the state shown in Figures 2 and 3, the boss portion 22 of the sealing element is inserted into the second part 132 of the injection hole, the injection mechanism 60 of the injection device 200 is inserted into the injection hole 13, and 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 1000 and is completely offset from the injection hole 13.

[0091] Continuing to refer to Figures 4 and 5, when the sealing element 20 moves to the second position, the elastic mechanism is in a compressed state, the sleeve 62 of the injection mechanism abuts against the step surface 133 inside the injection hole 13, and a portion of the piston 63 of the injection mechanism passes through the injection hole 13 into the interior of the battery cell 1000, and the electrolyte enters the interior of the battery cell 1000 along the outer wall of the columnar portion 632 of the piston.

[0092] When the sealing element 20 is in the second position, the elastic mechanism is in a compressed state. After the injection is completed, the cylinder 53 stops working, the pressure rod 54 drives the injection mechanism 60 to remove the injection hole 13, and the driving mechanism 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.

[0093] As shown in FIG. 3 , the elastic mechanism 30 may be a spring. In other alternative examples, as shown in FIG. 9 and FIG. 10 , the elastic mechanism 30 may also be an elastic member having a lantern structure.

[0094] In other optional examples, the driving structure can also be a magnetic part, and a magnetic adsorption effect is configured between the magnetic part and the sealing element 20. When the sealing element 20 is in the first position, no magnetic adsorption effect is formed between the magnetic part and the sealing element 20. When the sealing element 20 is in the second position, a magnetic adsorption effect is formed between the magnetic part and the sealing element 20.

[0095] In the above embodiment, 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 13, thereby causing the top cover assembly 100 to be unable to seal.

[0096] In some embodiments provided in the present application, a guide device 40 is further provided in the top cover assembly 100, and the guide device 40 is provided with a guide channel 42, and the guide channel 42 is configured to extend along a first direction, wherein the first direction is configured as the F direction indicated in Figure 2 or 3, and at least a portion of the sealing element 20 is configured to move along the guide channel 42. Due to the guiding effect of the above-mentioned guide device, the sealing element 20 moves under the guidance of the elastic mechanism 30, so that the portion of the sealing element 20 used to seal the injection hole 13 can accurately seal the injection hole 13.

[0097] In one embodiment, the guide channel 42 is arranged inside the guide device 40, and the guide device 40 is provided with a hollow first cavity 41, which defines the guide channel 42. The sealing element 20 is configured to move inside the guide channel 42, and one end of the guide channel 42 is connected to the injection hole 13, thereby guiding at least a portion of the sealing element 20 to move accurately to the inside of the injection hole 13 under the drive of the elastic mechanism 30.

[0098] In another optional embodiment, the guide channel 42 is arranged along the outer surface of the guide device 40, and the sealing element 20 is arranged outside the guide device 40. Specifically, the sealing element 20 can be sleeved on the outer wall of the guide device 40, and the sealing element 20 moves along the outer wall of the guide device 40.

[0099] Furthermore, when the sealing element 20 is sleeved on the outer wall of the guide device 40 , the position and shape of the liquid injection hole 13 on the cover plate 10 can be adjusted according to the shape of the sealing element 20 .

[0100] In the above embodiment, the sealing element 20 moves substantially along the height direction of the battery cell 1000 . Since the guide channel 42 extends in the same direction as the moving path of the sealing element 20 , the guide channel 42 is arranged in the same direction as the height direction of the battery cell 1000 .

[0101] Further referring to FIG. 11 to FIG. 16 , the elastic mechanism 30 is disposed inside the first cavity 41 , and the elastic mechanism 30 is configured to move along the axial direction of the guide device 40 .

[0102] In one embodiment provided in the present application, the insulating seat 12 is provided with a hollow second cavity 121, which is protruding relative to the main body of the insulating seat 12. The insulating seat 12 includes a first side wall 122 and a first bottom wall 123 that define the second cavity 121. A support platform 124 is provided on the first bottom wall 123, and the elastic mechanism 30 is fixed on the support platform 124. The elastic mechanism 30 is extended and retracted inside the second cavity 121, and the guide device 40 is provided inside the second cavity 121.

[0103] In other optional examples, the cover plate 10 is provided with a hollow inner cavity, and the other end of the above-mentioned elastic mechanism 30 is connected to the bottom wall of the inner cavity of the cover plate 10, wherein the guide device 40 is also provided in the inner cavity of the cover plate 10, and a nested structure is formed between the guide device 40 and the cover plate 10, and a first through hole can be adaptively provided on the side wall of the guide device 40, and a second through hole is further provided on the side wall or bottom wall where the inner cavity of the cover plate 10 is located. The electrolyte entering the inner cavity of the guide device 40 enters the inner cavity of the cover plate 10 through the first through hole on the guide device 40, and the electrolyte entering the inner cavity of the cover plate 10 further enters the interior of the battery cell through the second through hole.

[0104] Optionally, the side wall where the inner cavity of the cover plate 10 is located is enclosed to form a guide device 40, that is, a portion of the cover plate 10 is concave to form the guide device 40, and a through hole can be adaptively set on the side wall where the inner cavity of the cover plate 10 is located, and the electrolyte entering the inner cavity of the cover plate 10 enters the interior of the battery cell through the through hole.

[0105] Furthermore, the guide device 40 is configured as a cylindrical body with a hollow inner cavity, the inner cavity of the cylindrical body is configured to accommodate the sealing element 20, and the outer wall of the sealing element 20 abuts against the inner wall of the cylindrical body, so that the sealing element 20 is configured to move along the inner wall of the cylindrical body.

[0106] In a preferred embodiment, the guide device 40 is provided with a plurality of first liquid guide holes 46. The electrolyte flowing in through the liquid injection hole 13 enters the interior of the first cavity 41 and flows into the interior of the battery cell 1000 through the plurality of first liquid guide holes 46. Since the guide device 40 is disposed within the interior of the second cavity 121, the electrolyte flows out through the plurality of first liquid guide holes 46 and then enters the interior of the second cavity 121.

[0107] A plurality of second liquid guide holes 125 are provided on the first bottom wall 123 of the insulating seat. The electrolyte entering the second cavity 121 enters the interior of the battery cell 1000 through the plurality of second liquid guide holes 125 .

[0108] Furthermore, the guide device 40 includes a second side wall 43, and a plurality of first liquid guide holes 46 are arranged at intervals along the circumference of the second side wall 43, which is conducive to the injection of the electrolyte into the interior of the second cavity 121 along the circumference of the guide device 40. Compared with the related art, the electrolyte directly enters the interior of the battery cell through a single liquid injection hole. After the electrolyte flows out directly through a single liquid injection hole, it will flow out along the axial direction of the liquid injection hole and will generate a large fluid impact force on the projection surface of the liquid injection hole, thereby impacting the core assembly inside the battery cell 1000 and causing damage to the core assembly. By arranging the plurality of first liquid guide holes 46 along the circumference of the guide device 40, the electrolyte enters the interior of the second cavity 121 along the circumference, which can effectively alleviate the impact force formed by the fluid flowing out in a single direction, and the plurality of first liquid guide holes 46 divide the electrolyte into multiple tributaries, thereby effectively reducing the impact force of the fluid.

[0109] The first liquid guide hole 46 is configured as a strip-shaped hole, thereby increasing the diameter of the first liquid guide hole 46 and facilitating the outflow of the electrolyte. The first liquid guide hole 46 extends along the extension direction of the guide channel 42. When the sealing element 20 moves along the guide channel 42 from the first position to the second position, the electrolyte flows out along the first liquid guide hole 46, improving the efficiency of electrolyte drainage.

[0110] Multiple second liquid guide holes 125 are distributed on the first bottom wall 123 of the second cavity 121. At least a portion of the bottom wall of the insulating seat 12 is configured as a blocking wall 126. Multiple second liquid guide holes 125 are distributed on the portion of the first bottom wall 123 outside the blocking wall 126. The projection surface of the sealing element 20 on the first bottom wall 123 is located on the blocking wall 126. The blocking wall can effectively prevent the electrolyte from flowing out directly from the liquid injection hole 13 and impacting the core assembly.

[0111] Furthermore, the blocking wall 126 is protrudingly arranged to form a support platform 124, and the second liquid guide hole 125 is distributed on a portion of the first bottom wall 123 outside the support platform 124. The guide device 40 is configured to be arranged around the support platform 124. Further, the support platform 124 is arranged opposite the liquid injection hole 13, so that the portion of the first bottom wall 123 where the support platform 124 is located protects the core assembly inside the battery cell 1000, effectively preventing damage to the core assembly due to the liquid injection operation.

[0112] With further reference to Figures 11 to 13, in one embodiment provided in the present application, the above-mentioned guide device 40 is combined with the cover plate 10, and the guide device 40 is configured to be integrally formed with the cover plate 10. Specifically, the guide device 40 is configured as a first cylindrical portion 44 provided on the cover plate 10, and the first cylindrical portion 44 is provided around the injection hole 13. The bottom end of the first cylindrical portion 44 abuts against the first bottom wall 123 of the insulating seat, and the elastic mechanism 30 is accommodated inside the first cylindrical portion 44. The inner diameter of the first cylindrical portion 44 is configured to be substantially the same as the maximum outer diameter of the sealing element 20, so that the sealing element 20 can move inside the first cylindrical portion 44 under the pressure of the injection mechanism 60.

[0113] After the liquid injection operation is completed, the sealing element 20 is driven by the elastic mechanism 30 to move within the first cylindrical portion 44 toward the liquid injection hole 13 and enter the liquid injection hole 13 .

[0114] A first flange 441 is provided at the top end of the first cylindrical portion 44 . When the boss portion 22 of the sealing element is inserted into the liquid injection hole 13 , the main body portion 21 of the sealing element abuts against the first flange 441 .

[0115] In another alternative example, the top end of the guide device 40 may be fixed to the cover plate 10 .

[0116] In another embodiment of the present application, with reference to Figures 17 and 18, a guide device 40 is further provided, the guide device 40 includes a plurality of cylindrical portions 47, the sealing element 20 includes a plurality of guide portions 23, an elastic mechanism 30 is provided inside each cylindrical portion 47, each guide portion 23 is configured to move in the inner cavity of the cylindrical portion 47, and then the plurality of elastic mechanisms 30 are used to support a sealing element 20, so that the sealing element 20 can be stably accommodated in the interior of the top cover assembly 100 under the support of the plurality of elastic mechanisms 30, and further, the plurality of elastic mechanisms 30 are used to drive the sealing element 20 to move, so that the sealing element 20 can move more smoothly. The plurality of guide portions 23 move inside the plurality of cylindrical portions 47, so that the sealing element 20 can enter the interior of the injection hole 13 more accurately.

[0117] In a further preferred embodiment, in order to prevent the electrolyte from entering the interior of the cylindrical portion 47 and corroding the elastic mechanism 30, a sealing sleeve 70 is further provided inside the cylindrical portion 47. The sealing sleeve 70 is arranged to fit the inner wall of the cylindrical portion 47, and the guide portion 23 is coaxially arranged with the sealing sleeve 70. The elastic mechanism 30 and the guide portion 23 are configured to move in the inner cavity of the sealing sleeve 70, thereby effectively preventing the electrolyte from contacting the elastic mechanism 30.

[0118] Continuing to refer to Figures 14 to 16, in another embodiment provided in the present application, the above-mentioned guide device 40 is combined on the insulating seat 12, and the guide device 40 is configured to be integrally formed with the insulating seat 12. Specifically, the guide device 40 is configured as a second cylindrical portion 45 provided on the insulating seat 12, and the bottom end of the second cylindrical portion 45 is connected to the first bottom wall 123 of the insulating seat. The elastic mechanism 30 is further provided in the interior of the second cylindrical portion 45, and the top end of the second cylindrical portion 45 abuts against the cover plate 10.

[0119] In one embodiment of the present application, a method for injecting electrolyte into a battery cell 1000 is further provided. The battery cell includes the top cover assembly 100 described above. The battery cell uses the injection device 200 described above to inject electrolyte into the interior of the battery cell 1000. The injection method includes:

[0120] Insert the injection mechanism 60 of the injection device 200 into the injection hole 13 and make the injection mechanism 60 abut against one end of the sealing element 20;

[0121] Press the injection mechanism 60, and the sealing element 20 is driven by the injection mechanism to move from the first position to the second position along the guide channel 42, and the injection hole 13 is opened. The injection mechanism 60 injects the electrolyte into the interior of the battery cell through the injection hole 13;

[0122] Stop injection, remove the injection mechanism 60 from the injection hole 13, and drive the sealing element 20 along the guide channel 42 from the second position to the first position under the drive of the elastic mechanism 30. At least a portion of the sealing element 20 is inserted into the interior of the injection hole 13, and the injection hole 13 is closed.

[0123] Before the sealing element 20 moves to the second position, a portion of the columnar portion 632 and the base 631 enter the interior of the guide channel 42 through the injection hole 13. An electrolyte outlet is formed between the columnar portion 632 and the bottom opening 623 of the sleeve 62. The electrolyte enters the injection hole 13 through this outlet and flows into the battery cell through the injection hole 13. Another portion of the electrolyte flows directly into the battery cell along the columnar portion 632, effectively improving the efficiency of electrolyte introduction.

[0124] Furthermore, the injection mechanism 60 is also equipped with a sensing device for monitoring the injection rate of the injection mechanism 60 and controlling 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 use of the battery cell.

Claims

1. A top cover assembly, the top cover assembly being arranged on a battery cell, the top cover assembly comprising: Cover plate; A liquid injection hole, provided on the cover plate, and used to replenish electrolyte into the battery cell; A sealing element, wherein the sealing element is configured to be movable along a first direction between a first position and a second position relative to the cover plate, 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; a driving mechanism, the driving mechanism being used to drive the sealing element to move from the second position to the first position; A guide device is provided with a guide channel, wherein the guide channel extends along the first direction, and at least a portion of the sealing element is configured to move in the guide channel, so that at least a portion of the sealing element moves to the interior of the injection hole and seals the injection hole under the drive of the driving mechanism.

2. The top cover assembly according to claim 1, wherein: The guide device is provided with a hollow first cavity, which defines the guide channel, and the sealing element is configured to move inside the guide device.

3. The top cover assembly according to claim 1, wherein: The outer surface of the guide device is provided with the guide channel, and the sealing element is arranged outside the guide device and moves along the outer surface of the guide device.

4. The top cover assembly according to claim 2, wherein: One end of the guide channel is communicated with the liquid injection hole, and the first cavity is configured to accommodate the sealing element so that the sealing element moves inside the guide channel.

5. The top cover assembly according to claim 4, wherein: The driving mechanism comprises an elastic mechanism, the elastic mechanism is connected to one end of the sealing element, the elastic mechanism is arranged inside the first cavity, and the elastic mechanism is configured to move along the axial direction of the guide device.

6. The top cover assembly according to claim 5, wherein: The top cover assembly also includes an insulating seat connected to one side of the cover plate, the other end of the elastic mechanism is connected to the insulating seat, the insulating seat is provided with a hollow inner cavity, and the guide device is provided in the inner cavity of the insulating seat; Alternatively, the cover plate is provided with a hollow inner cavity, the other end of the elastic mechanism is connected to the bottom wall of the cover plate, and the guide device is provided in the inner cavity of the cover plate; Alternatively, the cover plate is provided with a hollow inner cavity, and the walls of the inner cavity of the cover plate are enclosed to form the guide device.

7. The top cover assembly according to claim 1, wherein: The guide device is configured as a cylindrical body having a hollow inner cavity, and the outer wall of the sealing element abuts against the inner wall of the cylindrical body so that the sealing element moves along the inner wall of the cylindrical body.

8. The top cover assembly according to claim 6, wherein: The insulating seat is provided with a hollow inner cavity, the guiding device is arranged in the inner cavity of the insulating seat, and the guiding device is provided with a plurality of first liquid guiding holes, and the plurality of first liquid guiding holes are used to guide the electrolyte into the inner cavity of the insulating seat.

9. The top cover assembly according to claim 8, wherein: The plurality of first liquid guiding holes are distributed at intervals along the circumference of the guiding device.

10. The top cover assembly according to claim 8, wherein: The insulating seat is provided with a plurality of second liquid guide holes, and the plurality of second liquid guide holes are arranged on the bottom wall of the insulating seat; The insulating seat comprises a blocking wall, the plurality of second liquid guiding holes are arranged on a portion of the bottom wall outside the blocking wall, and the blocking wall is arranged at the bottom of the guiding device.

11. The top cover assembly according to any one of claims 1 to 10, wherein: The guide device is combined with the cover plate, and the guide device includes a first cylindrical portion arranged on the cover plate, the first cylindrical portion is arranged around the injection hole, and the bottom end of the first cylindrical portion abuts against the bottom wall of the insulating seat.

12. The top cover assembly according to claim 11, wherein: The driving mechanism comprises an elastic mechanism, a support platform is arranged on the bottom wall of the insulating seat, the guiding device is arranged around the support platform, and the elastic mechanism is fixed on the support platform.

13. The top cover assembly according to any one of claims 1 to 10, wherein: The guide device is combined with the insulating seat, and the guide device includes a second cylindrical portion arranged on the insulating seat, the elastic mechanism is arranged inside the second cylindrical portion, and the top end of the second cylindrical portion abuts against the cover plate.

14. The top cover assembly according to claim 1, wherein: The sealing element includes a main body and a plurality of guide portions, the guide device includes a plurality of cylindrical portions, and the guide portions are configured to move inside the cylindrical portions.

15. The top cover assembly according to claim 13, wherein: The top cover assembly further comprises a sealing sleeve, which is arranged around the elastic mechanism.

16. The top cover assembly according to claim 5 or 6, wherein: The elastic mechanism is configured as a spring, or the elastic mechanism is configured as an elastic support beam capable of bending.

17. A method for injecting electrolyte into a battery cell, the battery cell comprising the top cover assembly according to any one of claims 1 to 16, the battery cell using an injection device to inject electrolyte into the battery cell, the injection device comprising an injection mechanism, the injection method comprising: Inserting the injection mechanism of the injection device into the injection hole, and making the injection mechanism abut against one end of the sealing element; The injection mechanism is pressed, and the sealing element is driven by the injection mechanism to move from the first position to the second position along the guide channel, the injection hole is opened, and the injection mechanism injects the electrolyte into the interior of the battery cell through the injection hole; The injection is stopped, the injection mechanism is removed from the injection hole, and the sealing element is driven by the driving mechanism to move from the second position to the first position along the guide channel, and the injection hole is closed.

18. The liquid injection method according to claim 17, wherein: The injection mechanism further includes a sensing device, and the sensing device is used to monitor the injection rate of the injection mechanism. The injection method further includes: The injection mechanism stops injecting after injection time T, and the injection time T is equal to the ratio of the capacity of the electrolyte required to be injected into the battery cell to the injection rate of the injection mechanism.

19. The liquid injection method according to claim 17, wherein: The injection mechanism includes a columnar portion and a base connected to one end of the columnar portion, the base is used to press the sealing element, and before the sealing element moves to the second position, it also includes: The base and a portion of the columnar portion enter the interior of the guide channel through the liquid injection hole.

20. A battery pack, comprising a plurality of battery cells, wherein the battery cells include the top cover assembly according to any one of claims 1 to 16, or the battery cells are injected with electrolyte using the injection method according to any one of claims 17 to 19.

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