Top cover assembly and battery

Abstract

The present application discloses a top cover assembly and a battery. The top cover assembly comprises a cover plate, a pressing plate, and a pole; a first through hole is formed in the cover plate; the pressing plate comprises a first end surface and a second end surface which are arranged opposite to each other; the pressing plate is provided with a variable-cross-section through hole; the pole sequentially passes through the first through hole and the variable-cross-section through hole; the first end surface faces the cover plate; and the opening area of the end of the variable-cross-section through hole facing the first end surface is a1, the opening area of the end of the variable-cross-section through hole facing the second end surface is a2, and the cross-sectional area of the pole is A, wherein a2≤A<a1.

Description

Top cover assembly and battery

[0001] This application claims priority to Chinese patent applications filed with the China Patent Office on June 21, 2023, with application numbers 202321598398.4, 202310743118.2 and 202321598171.X, respectively. 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. Background Art

[0003] In the related art, the top cover assembly usually includes structures such as a cover plate, an insulating assembly, a pressure plate and a pole. After the pole passes through the pressure plate, the pressure plate is pressed so that the cover plate and the insulating assembly are clamped between the pole and the pressure plate and tightly connected, and then welding is performed to achieve axial fixation of the top cover assembly. However, if the pole and the pressure plate are clearance fit, the size of the gap between the pole and the pressure plate is difficult to control, resulting in large differences between different products. If the pole and the pressure plate are interference fit, the two are in a tight fit state, which will squeeze the pressure plate, causing the entire pressure plate to deform and increasing the difficulty of assembly. Therefore, both of the above-mentioned matching relationships between the pole and the pressure plate will lead to a sharp increase in the production cost of the top cover assembly. SUMMARY OF THE INVENTION

[0004] The present application provides a new top cover assembly and battery to solve the above technical problems.

[0005] The present application provides a top cover assembly, including a cover plate, a pressure plate and a pole, wherein a first through hole is opened on the cover plate, the pressure plate includes a first end face and a second end face arranged opposite to each other, the pressure plate is provided with a variable-section through hole, the pole passes through the first through hole and the variable-section through hole in sequence, and the first end face faces the cover plate; the opening area of ​​the variable-section through hole toward one end of the first end face is a1, the opening area of ​​the variable-section through hole toward one end of the second end face is a2, and the cross-sectional area of ​​the pole is A, wherein a2≤A<a1.

[0006] The present application also provides a battery, comprising the above-mentioned top cover assembly. Beneficial effects

[0007] The beneficial effects of the present application are as follows: the top cover assembly provided by the present application has an opening area of ​​a1 through the variable-section through hole toward one end of the first end face, an opening area of ​​a2 through the variable-section through hole toward one end of the second end face, and a cross-sectional area of ​​the pole is A, wherein a2≤A<a1. It can ensure that when the pole and the pressure plate are matched, the second end face and the pole are zero-matched or slightly tightly matched, avoiding a gap between the pole and the pressure plate. Through the clearance fit between the first end face and the pole, the pressure plate and the pole are clearance-matched in at least part of the area, effectively preventing the pressure ring from being squeezed, avoiding deformation of the entire pressure ring, and reducing the difficulty of assembly. The variable-section through hole provided on the above-mentioned pressure plate and the matching relationship between the variable-section through hole and the pole reduce the production cost of the top cover assembly.

[0008] The battery provided herein employs the aforementioned top cover assembly, which can avoid gaps between the terminal post and the pressure plate, effectively prevent squeezing of the pressure ring, and avoid deformation of the entire pressure ring, thereby reducing assembly difficulty. Therefore, the quality of the battery provided herein can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG1 is an exploded view of a top cover assembly provided in an embodiment of the present application;

[0010] FIG2 is a schematic structural diagram of a pressure plate provided in an embodiment of the present application;

[0011] FIG3 is a cross-sectional view taken along line AA of FIG2 ;

[0012] FIG4 is a schematic structural diagram of a pole provided in an embodiment of the present application;

[0013] FIG5 is a front view of a pole provided in an embodiment of the present application;

[0014] FIG6 is a perspective structural diagram of a first insulating plate provided in an embodiment of the present application;

[0015] FIG7 is a partial cross-sectional view of a top cover assembly provided in an embodiment of the present application;

[0016] FIG8 is an enlarged view of point P in FIG7 .

[0017] Description of reference numerals:

[0018] 1. Cover plate; 10. First through hole; 11. Groove; 12. Liquid injection hole; 2. Press plate; 21. First end face; 22. Second end face; 23. Variable-section through hole; 24. Limiting groove; 3. First insulating plate; 31. Second through hole; 32. Ventilation groove; 321. Annular portion; 322. Radial portion; 33. Mounting groove; 34. Limiting platform; 35. Isolation protrusion; 36. Enclosure; 4. Pole; 41. Flange; 5. Second insulating plate; 51. Limiting protrusion; 6. Sealing ring; 7. Protective film; 8. Explosion-proof valve; N. Accommodating chamber; M1. Gas channel; M2. External exhaust channel; M. Exhaust channel. Modes for Carrying Out the Invention

[0019] In the description of this application, unless otherwise specified or limited, the terms "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and can refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0020] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0021] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0022] Example 1

[0023] An embodiment of the present application provides a battery, which includes a top cover assembly, and the top cover assembly can be used as a top cover of the battery.

[0024] As shown in Figures 1-5, the top cover assembly includes a cover plate 1, a pressure plate 2, and a pole 4. The cover plate 1 has a first through-hole 10, and the pressure plate 2 includes a first end face 21 and a second end face 22 that are oppositely disposed. The pressure plate 2 is provided with a variable-section through-hole 23. The pole 4 passes through the first through-hole 10 and the variable-section through-hole 23 in the cover plate 1 in sequence, with the first end face 21 facing the cover plate 1, thereby connecting the pole 4, the pressure plate 2, and the cover plate 1. Exemplarily, the pole 4 and the pressure plate 2 are connected by welding.

[0025] The opening area of ​​the variable-cross-section through hole 23 facing the first end face 21 is a1, the opening area of ​​the variable-cross-section through hole 23 facing the second end face 22 is a2, and the cross-sectional area of ​​the pole 4 is A, where a2≤A<a1. This dimensional relationship ensures that when the pole 4 and the pressure plate 2 are mated, the end of the variable-cross-section through hole 23 facing the second end face 22 is a zero fit or a tight fit with the pole 4, thereby avoiding a gap between the pole 4 and the pressure plate 2. When the pole 4 and the pressure plate 2 are fixed by laser welding, the variability of the weld gap caused by dimensional fluctuations is reduced, thereby significantly improving the yield rate of the laser welding between the pole 4 and the pressure plate 2.

[0026] Exemplarily, the top cover assembly further includes a sealing ring 6. Due to the aforementioned fit between the pole 4 and the pressure plate 2, a gap is avoided between the pole 4 and the second end surface 22 of the pressure plate 2, thereby ensuring that there is no laser light leakage during laser welding. This also avoids the risk of laser light leakage burning the sealing ring 6 and causing sealing failure.

[0027] Furthermore, by providing a clearance fit between the end of the variable-section through-hole 23 facing the first end face 21 and the pole 4, the pressure plate 2 and at least a portion of the pole 4 are clearance-fitted to form a receiving cavity N. The expanded gas generated in the heated area within the pole 4 during welding can be accommodated within the receiving cavity N, thereby avoiding the problem in the prior art where the expanded gas squeezes the pressure ring, causing deformation of the entire pressure ring, and the expanded gas forms cavities within the ring, ultimately leading to welding failure. The provision of the variable-section through-hole 23 in the pressure plate 2 and the matching relationship between the variable-section through-hole 23 and the pole 4 improves the welding yield, reduces the welding difficulty, and reduces the production cost of the top cover assembly.

[0028] As shown in Figure 3, the opening area of ​​the variable-cross-section through hole 23 decreases gradually from the first end face 21 to the second end face 22, which can provide a guiding effect, ensuring that the pressure plate 2 and the terminal 4 are more easily inserted into the terminal 4 during assembly, thereby reducing the difficulty of assembly. In one embodiment, the variable-cross-section through hole 23 is flared. In other embodiments, the variable-cross-section through hole 23 is conical or has other shapes, which are not limited in this application.

[0029] As shown in Figures 3 and 5, the cross-sectional shape of the variable-section through hole 23 and the pole 4 is the same. Both are regular shapes or irregular shapes such as circles, ellipses, and rectangles. There is no limitation on this. As long as the second end face 22 and the pole 4 are zero-fit or tight-fit, and the first end face 21 and the pole 4 are clearance-fitted, it will be sufficient.

[0030] In one embodiment, the cross-sectional shapes of the variable-section through hole 23 and the pole 4 are both circular, wherein the diameter of the pole 4 is D, the aperture of the variable-section through hole 23 at one end facing the first end face 21 is d1, and the aperture of the variable-section through hole 23 at one end facing the second end face 22 is d2, wherein d2≤D<d1, which facilitates the production of the variable-section through hole 23 and easily ensures the matching accuracy between the two.

[0031] In one embodiment, d1-d2 = B, where B is in the range of 0.1mm-0.3mm, and specifically can be 0.1mm, 0.2mm, or 0.3mm, etc. This arrangement creates a larger gap between the two, facilitating installation while also forming a larger accommodating cavity N. D-d2 = C, where C is in the range of 0-0.05mm, and specifically can be 0, 0.01mm, 0.02mm, 0.03mm, 0.04mm, or 0.05mm, etc. This allows for a zero fit or a slightly tight fit between the end of the variable-cross-section through hole 23 facing the second end face 22 and the pole 4, thereby improving installation convenience.

[0032] In one embodiment, as shown in FIG1 , the top cover assembly further includes an insulating member, which is used to provide an insulated connection between the pole 4 and the cover plate 1, and between the cover plate 1 and the pressure plate 2. The insulating member may include a first insulating plate 3 and a second insulating plate 5, which are disposed on either side of the cover plate 1. The pole 4 passes through the first insulating plate 3 and the second insulating plate 5. The first insulating plate 3 and the second insulating plate 5 may be an integral structure or a separate structure.

[0033] The first insulating plate 3 is sandwiched between the pressing plate 2 and the cover plate 1, with the first end face 21 facing the first insulating plate 3. A second through hole 31 is provided on the first insulating plate 3, and the pole 4 passes through the first through hole 10, the second through hole 31 and the variable-section through hole 23 in sequence; a gas channel M1 is formed between the first insulating plate 3 and the pressing plate 2, and the variable-section through hole 23 is connected to the outside world through the gas channel M1.

[0034] During assembly, the pole 4 is first passed through the first through hole 10, the second through hole 31, and the variable-section through hole 23 in sequence. The pole 4 is then welded to the pressure plate 2 to secure the pressure plate 2 and the pole 4, thereby achieving an axial connection of the top cover assembly. When the pole 4 is welded, the expanded gas generated in the heated area inside can be discharged promptly through the gas channel M1, avoiding the formation of holes in the weld. This improves the welding yield and, in turn, the battery quality. The direction of the expanded gas discharge is indicated by the arrow in Figure 8.

[0035] In one embodiment, as shown in Figures 1 and 6, the first insulating plate 3 has a vent groove 32 on the side facing the pressure plate 2. The vent groove 32 connects the second through hole 31, the variable-section through hole 23, and the outside world. The vent groove 32 and the pressure plate 2 together define a gas channel M1. The first insulating plate 3 and the pressure plate 2 can be of any thickness and shape. For example, the first insulating plate 3 and the pressure plate 2 can be flat plates, wedge-shaped plates, etc. The vent groove 32 can be of any shape, depth, and width. For example, it can be a straight groove, an arc groove, or a curved groove. This is not limited in this application, as long as it ensures that the expanded gas can be discharged through the gas channel M1.

[0036] Illustratively, the first insulating plate 3 and the pressing plate 2 are both flat-plate shaped, and the ventilation groove 32 is provided on the side of the first insulating plate 3 facing the pressing plate 2 , which has a simple structure and is convenient for assembly.

[0037] In one embodiment, an exhaust groove is provided on the side of the pressing plate 2 facing the first insulating plate 3 (i.e., the first end face 21 of the pressing plate 2), and the exhaust groove connects the second through hole 31, the variable-section through hole 23 and the outside world. The exhaust groove and the first insulating plate 3 jointly define the above-mentioned gas channel M1.

[0038] For example, when the first insulating plate 3 and the pressing plate 2 are both in the shape of flat plates, the exhaust groove is opened on the first end surface 21 of the pressing plate 2 .

[0039] In another example, when the first insulating plate 3 is provided with a mounting groove 33 and the pressing plate 2 is in a flat plate shape, the pressing plate 2 is arranged in the mounting groove 33, and a gap is provided between the outer peripheral surface of the pressing plate 2 and the side wall of the first insulating plate 3 located in the mounting groove 33. The exhaust groove is opened on the end surface of the pressing plate 2 facing the bottom of the mounting groove 33 (that is, the first end surface 21 of the pressing plate 2), and the exhaust groove is connected to the outside through the gap.

[0040] The present application does not limit the shapes of the vent groove 32 and the exhaust groove. For ease of description, the following embodiments of the present application are described using the structure of the vent groove 32 as an example.

[0041] In one embodiment, the pressure plate 2 and the pole 4 are clearance-matched in at least part of the area to form a receiving chamber N, one end of the gas channel M1 is connected to the receiving chamber N, and the other end of the gas channel M1 is connected to the outside. By providing the gas channel M1, it is ensured that the expanded air generated during welding can be discharged to the outside through the receiving chamber N and the gas channel M1 in sequence, and no holes will be formed inside, thereby improving the welding yield. This further avoids the problem in the prior art that due to the tight fit between the pole 4 and the pressure ring, the expanded gas generated in the heated area inside the pole 4 during welding cannot be discharged from the weld, and the expanded gas will squeeze the pressure ring, causing the entire pressure ring to deform and the welding to fail.

[0042] In one embodiment, as shown in Figures 6-8 , the first insulating plate 3 is provided with a mounting groove 33. The bottom wall of the mounting groove 33 supports the first end surface 21. A second through hole 31 is provided in the bottom wall of the mounting groove 33. A vent groove 32 is also provided in the bottom wall of the mounting groove 33, communicating with the second through hole 31. The first end surface 21 and the vent groove 32 together define a gas channel M1. The gap between the sidewalls of the mounting groove 33 and the side of the pressing plate 2 together defines an exhaust channel M2. The gas channel M1 and the exhaust channel M2 communicate with each other to form an exhaust channel M. The gas channel M1 communicates with the accommodating chamber N, while the exhaust channel M2 communicates with the outside world. Expanded air can be discharged to the outside world through the gas channel M1 and the exhaust channel M2 in sequence. Mounting the pressing plate 2 in the mounting groove 33 helps prevent the peripheral side of the pressing plate 2 from contacting the outside world, thereby improving structural reliability. In other embodiments, a through hole can be provided in the sidewall of the mounting groove 33, so that the other end of the vent groove 32 communicates with the through hole, thereby communicating with the outside world.

[0043] Exemplarily, a barrier 36 is provided on the first insulating plate 3 , and the mounting groove 33 can be defined by the barrier 36 .

[0044] In one embodiment, the mounting groove 33 is a polygonal groove, and the pressure plate 2 is a polygonal plate. The shapes of the pressure plate 2 and the mounting groove 33 are adapted to each other, and the pressure plate 2 can achieve circumferential position restriction when installed in the mounting groove 33. The number of sides of the polygon can be three, four, five, six, seven, or eight, and preferably, the polygon is a symmetrical shape.

[0045] When a gap (i.e., an external discharge channel M2) is provided between the outer circumference of the pressing plate 2 and the side wall of the mounting groove 33, the following situations are included: Optionally, the cross-sectional area of ​​the pressing plate 2 (i.e., the outer circumferential area of ​​the first end face 21 or the second end face 22) is smaller than the slot area of ​​the mounting groove 33, thereby forming an annular gap between the pressing plate 2 and the side wall of the mounting groove 33 (i.e., the enclosure 36), ensuring that the gas channel M1 at any position can be connected to the annular gap (i.e., the external discharge channel M2). Alternatively, a recessed groove is provided on the outer circumferential surface of the pressing plate 2 and / or the side wall of the mounting groove 33 (e.g., the inner side of the enclosure 36), and the above-mentioned external discharge channel M2 is formed between the outer circumferential surface of the pressing plate 2 and the side wall of the mounting groove 33 through the recessed groove, wherein the recessed groove and the gas channel M1 can be connected, and the shape and position are not limited.

[0046] In one embodiment, as shown in FIG6 , the vent groove 32 includes an annular portion 321 and a radial portion 322. The annular portion 321 communicates with the second through hole 31. One end of the radial portion 322 communicates with the annular portion 321, and the other end extends to the sidewall of the mounting groove 33. The annular portion 321 and the first end surface 21 define an annular channel, while the radial portion 322 and the first end surface 21 define a linear channel. The annular channel and the linear channel form a gas channel M1. The annular channel communicates with the accommodating cavity N, while the linear channel communicates with the annular channel and the exhaust channel M2. During laser welding, the gas in the heated area expands. The expanded gas flows through the annular channel to the nearest linear channel, and then flows through the linear channel to the exhaust channel M2 for discharge.

[0047] Exemplarily, there are multiple radial portions 322 , which are evenly distributed along the outer circumference of the annular portion 321 . After the inflation gas enters the annular portion 321 , it can be discharged outward from the nearest radial portion 322 , thereby further improving the discharge efficiency of the inflation gas.

[0048] For example, the radial portion 322 may be an S-shaped curved groove or an arc-shaped groove, etc. The number of radial portions 322 may be one, two, three, four, or five, etc. The shapes and depths of the radial portions 322 may be the same or different, and the annular portion 321 may be a ring with uniform width or a ring with uneven width.

[0049] In another embodiment, one end of the ventilation groove 32 is connected to the second through hole 31, and the other end extends to the side wall of the mounting groove 33. The shape is not limited. For example, the ventilation groove 32 is arranged radially, and one or more ventilation grooves 32 are provided. As long as the ventilation groove 32 and the first end face 21 form a gas channel M1, the expanded air can be discharged to the outside.

[0050] Furthermore, the depth of the vent groove 32 is 0.1mm-0.2mm, specifically 0.1mm, 0.15mm, or 0.2mm. This prevents excessive depth from affecting structural strength, while also preventing excessive depth from affecting exhaust. For example, the radial portion 322 and the annular portion 321 have the same depth, both ranging from 0.1mm-0.2mm, specifically 0.1mm, 0.15mm, and 0.2mm.

[0051] In one embodiment, as shown in Figures 2 and 6 , one of the pressure plate 2 and the first insulating plate 3 is provided with a limiting groove 24, and the other is provided with a limiting platform 34. The limiting platform 34 is mounted on the limiting groove 24 to limit the pressure plate 2 and the first insulating plate 3, and can also achieve circumferential positioning. This can improve the installation accuracy of both. There are multiple limiting platforms 34 and an equal number of limiting grooves 24. The cross-sectional shape of the limiting grooves 24 and limiting platforms 34 can be circular, elliptical, oblong, polygonal, or irregular, etc.

[0052] It should be noted that Figures 2 and 6 illustrate only the example of a configuration in which the limiting groove 24 is provided on the pressing plate 2 and the limiting platform 34 is provided on the first insulating plate 3. Of course, in some examples, the limiting groove may also be provided on the first insulating plate 3, while the limiting platform may be provided on the pressing plate 2. This application does not impose any limitations on this.

[0053] In this embodiment, as shown in FIG. 2 and FIG. 6 , four radial portions 322 , four limiting grooves 24 and four limiting platforms 34 are provided, and the four limiting platforms 34 and the four radial portions 322 are alternately arranged.

[0054] As shown in Figures 1, 4 and 7, the top cover assembly is also provided with a second insulating plate 5, and a flange 41 is provided on the outer periphery of the pole 4. The second insulating plate 5 is clamped between the flange 41 and the cover plate 1, and is arranged through the pressing plate 2, so that the first insulating plate 3, the cover plate 1 and the second insulating plate 5 are clamped between the pressing plate 2 and the flange 41.

[0055] It is worth noting that, in FIG7 , the pattern filled with the flange 41 is different from the pattern filled with the pole 4 above it, but the flange 41 and the pole 4 are actually an integrated structure as shown in FIG4 .

[0056] As shown in Figure 1, there are two poles 4, one is the positive pole and the other is the negative pole, and the two have the same external dimensions. The positive pole is made of aluminum and is formed by pier pressing. The negative pole is made of copper-aluminum composite plate and is formed by a combination of pier pressing and machining. The specific machining process and upsetting forming process are both existing technologies and will not be repeated here. They have high versatility and assembly convenience, and simplify the production process of the top cover assembly. There are two pressing plates 2, and the two poles 4 are connected to the two pressing plates 2 accordingly. There are two first insulating plates 3, and the first insulating plate 3 and the second insulating plate 5 are both plastic plates, and the two first insulating plates 3 have the same shape and size. The cover plate 1 is provided with two grooves 11, and the two first insulating plates 3 are respectively limited in the two grooves 11. The grooves 11 are polygonal grooves, and the first insulating plates 3 are polygonal plates, which prevent the first insulating plates 3 from rotating in the polygonal grooves to achieve position limiting.

[0057] As shown in Figure 8, the through hole of the cover plate 1 is larger than the diameter of the pole 4. An isolation protrusion 35 is provided on the side of the first insulating plate 3 facing away from the mounting groove 33. The isolation protrusion 35 extends into the first through hole 10 of the cover plate 1 to isolate the pole 4 from the cover plate 1. The sealing ring 6 is provided in the through hole of the second insulating plate 5 to isolate the pole 4 from the second insulating plate 5, and the cover plate 1 is provided on one side of the sealing ring 6 and the second insulating plate 5 to prevent contact between the pole 4 and the cover plate 1.

[0058] As shown in Figure 1, the second insulating plate 5 is provided with a limiting protrusion 51, and the limiting protrusion 51 is provided in the second mounting groove to achieve the limitation between the cover plate 1 and the second insulating plate 5 along the cross-sectional direction of the pole 4. The cover plate 1 is provided with a liquid injection hole 12. After the top cover assembly and the shell are connected, the electrolyte is injected into the shell through the liquid injection hole 12. The cover plate 1 is provided with an explosion-proof hole, and the second insulating plate 5 is provided with a corresponding hole. An explosion-proof valve 8 is installed on the explosion-proof hole. When the internal air pressure is too high, the explosion-proof valve 8 opens, and the gas is discharged through the second insulating plate 5 and the explosion-proof hole to achieve pressure relief. The explosion-proof valve 8 and the cover plate 1 are fixed by welding, and then the protective film 7 is attached to the upper side of the explosion-proof valve 8. The explosion-proof valve 8 can adopt the existing structure and will not be repeated.

[0059] When assembling the top cover assembly, the pole 4 passes through the sealing ring 6, the second insulating plate 5, the cover plate 1, the first insulating plate 3 and the pressure plate 2 in sequence. The pressure plate 2 is axially pressed and fixedly connected to the pole 4 by laser welding. The second insulating plate 5 and the cover plate 1 are fixed by ultrasonic hot melting.

[0060] Example 2

[0061] In the prior art, battery top cover assemblies are typically manufactured using processes such as overmolding and riveting the terminals. However, the structure and manufacturing process of these top cover assemblies are complex, hindering battery manufacturing efficiency and cost, and are gradually being phased out. Currently, the main method for securing the terminals is to weld the terminals to a pressure plate on the top cover assembly. During terminal welding, the expanding gases generated in the heated area inside the terminals cannot escape through the weld, forming internal holes that can lead to weld failure and affect battery quality.

[0062] As for the top cover assembly provided in the embodiment of the present application, as shown in Figures 1, 6 and 8, the top cover assembly includes a cover plate 1, a pressure plate 2, a first insulating plate 3 and a pole 4; wherein, the first insulating plate 3 is clamped between the pressure plate 2 and the cover plate 1, a first through hole 10 is provided on the cover plate 1, the pressure plate 2 is provided with a through hole (for example, a variable-section through hole 23), a second through hole 31 is provided on the first insulating plate 3, the pole 4 passes through the first through hole 10, the second through hole 31 and the through hole on the pressure plate 2 in sequence, and the pole 4 and the pressure plate 2 are welded; a gas channel M1 is formed between the first insulating plate 3 and the pressure plate 2, and the through hole on the pressure plate 2 is connected to the outside world through the gas channel M1.

[0063] During assembly, the terminal 4 is first passed through the first through-hole 10, the second through-hole 31, and the through-hole of the pressure plate 2. The terminal 4 is then welded to the pressure plate 2, thereby securing the pressure plate 2 and the terminal 4 and achieving an axial connection of the top cover assembly. During welding of the terminal 4, the expanding gas generated in the heated area inside is promptly discharged through the gas passage M1, preventing the formation of holes within the weld. This improves the welding yield and, in turn, the battery quality.

[0064] It is worth noting that the top cover assembly provided in the second embodiment can also adaptively include any embodiment or solution related to the top cover assembly in the first embodiment, which will not be described in detail here.

[0065] Obviously, the above embodiments of the present application are merely examples for the purpose of clearly illustrating the present application, and are not intended to limit the embodiments of the present application. For those skilled in the art, other variations or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present application shall be included within the scope of protection of the claims of the present application.

Claims

1. A top cover assembly, comprising a cover plate (1), a pressure plate (2) and a pole (4), wherein the cover plate (1) is provided with a first through hole (10), the pressure plate (2) comprises a first end face (21) and a second end face (22) arranged opposite to each other, the pressure plate (2) is provided with a variable cross-section through hole (23), the pole (4) passes through the first through hole (10) and the variable cross-section through hole (23) in sequence, and the first end face (21) faces the cover plate (1); The opening area of ​​the variable cross-section through hole (23) facing the first end surface (21) is a1, the opening area of ​​the variable cross-section through hole (23) facing the second end surface (22) is a2, and the cross-sectional area of ​​the pole (4) is A, wherein: a2≤A<a1.

2. The top cover assembly according to claim 1, wherein: The diameter of the pole (4) is D, the aperture of the variable cross-section through hole (23) at one end facing the first end face (21) is d1, and the aperture of the variable cross-section through hole (23) at one end facing the second end face (22) is d2, wherein d2≤D<d1.

3. The top cover assembly according to claim 2, wherein: d1-d2=B, where B is in the range of 0.1mm-0.3mm; and / or D-d2=C, the value range of C is 0-0.05mm.

4. The top cover assembly according to claim 1, wherein: The variable cross-section through hole (23) is in a trumpet-mouth shape.

5. The top cover assembly according to any one of claims 1 to 4, wherein: The invention also comprises a first insulating plate (3), wherein the first insulating plate (3) is sandwiched between the pressing plate (2) and the cover plate (1), the first end surface (21) faces the first insulating plate (3), the first insulating plate (3) is provided with a second through hole (31), the pole (4) passes through the first through hole (10), the second through hole (31) and the variable cross-section through hole (23) in sequence; a gas channel (M1) is formed between the first insulating plate (3) and the pressing plate (2), and the variable cross-section through hole (23) is connected to the outside through the gas channel (M1).

6. The top cover assembly according to claim 5, wherein: The first insulating plate (3) is provided with a ventilation groove (32) on the side facing the pressing plate (2), and the ventilation groove (32) and the pressing plate (2) together define the gas channel (M1); and / or The first end surface (21) of the pressing plate (2) is provided with an exhaust groove, and the exhaust groove and the first insulating plate (3) together define the gas channel (M1).

7. The top cover assembly according to claim 6, wherein: The first insulating plate (3) and the pressing plate (2) are both flat-plate shaped, the ventilation groove (32) is opened on the side of the first insulating plate (3) facing the pressing plate (2), and / or the exhaust groove is opened on the first end surface (21) of the pressing plate (2).

8. The top cover assembly according to claim 5, wherein: The pressing plate (2) and the pole (4) are clearance-matched in at least a portion of their regions to form a receiving cavity (N); one end of the gas channel (M1) is in communication with the receiving cavity (N), and the other end of the gas channel (M1) is in communication with the outside.

9. The top cover assembly according to claim 8, wherein: The first insulating plate (3) is provided with a mounting groove (33), the bottom wall of the mounting groove (33) supports the first end face (21), the second through hole (31) is provided on the bottom wall of the mounting groove (33), and a ventilation groove (32) connected to the second through hole (31) is also provided on the bottom wall of the mounting groove (33), the first end face (21) and the ventilation groove (32) jointly define the gas channel (M1), the gap between the side wall of the mounting groove (33) and the side surface of the pressing plate (2) jointly define an external exhaust channel (M2), the gas channel (M1) and the external exhaust channel (M2) are connected to form an exhaust channel (M), the gas channel (M1) is connected to the accommodating chamber (N), and the external exhaust channel (M2) is connected to the outside.

10. The top cover assembly according to claim 9, wherein: The mounting groove (33) is a polygonal groove, the pressing plate (2) is a polygonal plate, and the shapes of the pressing plate (2) and the mounting groove (33) are adapted to each other.

11. The top cover assembly according to claim 9, wherein: The cross-sectional area of ​​the pressing plate (2) is smaller than the slot area of ​​the mounting groove (33), so that an annular gap is formed between the pressing plate (2) and the side wall of the mounting groove (33).

12. The top cover assembly according to claim 9, wherein: A recessed groove is provided on the side of the pressing plate (2) and / or the side wall of the mounting groove (33), so that the external discharge channel (M2) is formed between the side of the pressing plate (2) and the side wall of the mounting groove (33), wherein the recessed groove is connected to the gas channel (M1).

13. The top cover assembly according to claim 9, wherein: The ventilation groove (32) comprises an annular portion (321) and a radial portion (322); the annular portion (321) is connected to the second through hole (31); one end of the radial portion (322) is connected to the annular portion (321) and the other end extends to the side wall of the mounting groove (33).

14. The top cover assembly according to claim 13, wherein: A plurality of radial portions (322) are provided, and the plurality of radial portions (322) are evenly distributed along the outer circumference of the annular portion (321).

15. The top cover assembly according to claim 9, wherein: The depth of the ventilation groove (32) is 0.1 mm-0.2 mm.

16. The top cover assembly according to any one of claims 1 to 15, wherein: One of the pressing plate (2) and the first insulating plate (3) is provided with a limiting groove (24), and the other is provided with a limiting platform (34), and the limiting platform (34) is installed in the limiting groove (24) to limit the pressing plate (2) and the first insulating plate (3).

17. The top cover assembly according to any one of claims 1 to 16, wherein: It also comprises a second insulating plate (5), the outer periphery of the pole (4) is provided with a flange (41), the pole (4) passes through the second insulating plate (5), and the second insulating plate (5) is sandwiched between the flange (41) and the cover plate (1).

18. The top cover assembly according to any one of claims 1 to 17, wherein: The pole (4) and the pressure plate (2) are connected by welding.

19. The top cover assembly according to any one of claims 1 to 18, wherein: When the pole (4) is a positive pole, the material of the positive pole is aluminum, and the positive pole is formed by piercing; and / or When the pole (4) is a negative pole, the material of the negative pole is a copper-aluminum composite plate, and the negative pole is formed by a combination of piercing and machining.

20. A battery comprising the top cover assembly according to any one of claims 1 to 19.

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