Cover plate assembly, battery monomer and electric equipment

Abstract

The utility model belongs to the technical field of batteries, and discloses a cover plate assembly, a battery monomer and electric equipment. The cover plate assembly comprises a cover plate main body and a sealing piece, a containing groove is formed in the cover plate main body, and a liquid injection hole penetrating through the cover plate main body is formed in the groove bottom of the containing groove; the sealing piece is arranged in the containing groove, a welding bead is formed between the peripheral side wall of the sealing piece and the side wall of the containing groove, and the depth h of the welding bead and the thickness z of the sealing piece meet the condition that h is larger than or equal to 0.3 z. The relationship between the depth of the welding bead and the thickness of the sealing element is set in the range, so that the depth and the structural strength of the welding bead can be ensured, the sealing reliability of the sealing element is ensured, the crack defect is avoided, and the liquid leakage risk is avoided.

Description

Technical Field

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

[0002] During the production process of power batteries, liquid injection operations are required. After the liquid injection is completed, the liquid injection channel on the battery cover needs to be sealed to ensure the safety of the battery cell during use. A receiving groove is provided on the battery cover, and a liquid injection hole is provided at the bottom of the receiving groove that passes through the battery cover. The sealing process includes using elastic sealing nails to seal the liquid injection hole to block the channel for the internal electrolyte to leak outward, and then placing the seal into the receiving groove, and laser welding the edge of the seal and the edge of the receiving groove to form a weld, and finally completing the sealing. In the cover assembly of power batteries currently on the market, the depth of the weld between the seal and the receiving groove is designed to be shallow, and the welding strength is poor, which will cause cracks in the weld, thereby affecting the sealing of the seal.

[0003] Therefore, there is an urgent need to provide a cover plate assembly, a battery cell and an electrical device to solve the above problems. Utility Model Content

[0004] The first object of the present application is to provide a cover plate assembly that can improve the quality of the weld and ensure the sealing reliability of the seal.

[0005] The second object of the present application is to provide a battery cell that can improve sealing reliability.

[0006] The third purpose of this application is to provide an electrical device that can ensure safety performance.

[0007] To achieve this goal, this application adopts the following technical solutions:

[0008] Cover assembly, including:

[0009] A cover plate body is provided with a receiving groove, and a liquid injection hole is provided at the bottom of the receiving groove and penetrates the cover plate body;

[0010] A seal is disposed in the accommodating groove, and a weld is formed between the outer peripheral side wall of the seal and the side wall of the accommodating groove. The depth h of the weld and the thickness z of the seal satisfy: h is greater than or equal to 0.3z.

[0011] As an optional solution, the depth h of the weld and the thickness z of the seal also satisfy the following condition: h is less than or equal to 1.5z.

[0012] As an optional solution, the receiving groove is coaxially arranged with the injection hole, the radial dimension of the receiving groove is larger than the radial dimension of the injection hole, and a step surface is formed at the connection between the receiving groove and the injection hole, and the bottom end of the seal can abut against the step surface.

[0013] As an optional solution, the cover plate assembly further includes a sealing pin, which is interference-fitted in the liquid injection hole, and a side of the sealing member close to the liquid injection hole is recessed with an avoidance groove for avoiding the sealing pin.

[0014] As an optional solution, the radial dimension of the avoidance groove is larger than the radial dimension of the injection hole.

[0015] As an optional solution, the sealing pin includes a sealing portion and a boss portion that are connected to each other, the radial dimension of the boss portion is larger than the radial dimension of the sealing portion, the sealing portion is embedded in the injection hole, and the end face of the boss portion close to the sealing portion abuts against the step surface, and the avoidance groove is used to avoid the boss portion.

[0016] As an optional solution, the circumferential side wall of the receiving groove is a slope, and the diameter of the receiving groove gradually increases along the axial direction of the receiving groove and gradually away from the injection hole, and the outer circumferential side wall of the seal is a slope adapted to the receiving groove.

[0017] As an optional solution, the weld includes a first region and a second region along the thickness direction of the cover plate body, the width of the first region is greater than the width of the second region, and the depth of the second region is greater than the depth of the first region.

[0018] A battery cell includes the above-mentioned cover plate assembly.

[0019] The electric equipment includes the battery cell mentioned above.

[0020] Beneficial effects of this application:

[0021] The present application provides a cover plate assembly in which a weld bead is formed between the outer peripheral sidewall of a seal and the sidewall of a receiving groove by welding. The weld bead depth h and the seal thickness z satisfy the following relationship: h is greater than or equal to 0.3z. By setting the relationship between the weld bead depth and the seal thickness within the aforementioned range, the weld bead depth and structural strength can be maintained, thereby ensuring the sealing reliability of the seal, avoiding crack defects, and thus minimizing the risk of leakage.

[0022] The present application also provides a battery cell, which improves the sealing reliability of the battery cell by providing the above-mentioned cover plate assembly.

[0023] The present application also provides an electrical device, which improves the safety performance of the electrical device by providing the above-mentioned battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a cross-sectional view of the cover plate assembly after explosion provided in Example 1 of the present application;

[0025] Figure 2 is a cross-sectional view of the cover plate assembly provided in Example 1 of the present application;

[0026] Figure 3 is a top view of the seal provided in Example 1 of the present application in cooperation with the receiving groove;

[0027] Figure 4 This is a partial enlarged view of the weld provided in Example 1 of the present application;

[0028] Figure 5 This is a partial enlarged view of the weld provided in Example 2 of the present application;

[0029] Figure 6 This is a partial enlarged view of the weld provided in Example 2 of the present application.

[0030] In the picture:

[0031] 100, gap; 101, dividing line;

[0032] 10. Cover plate body; 11. Receiving groove; 111. Top groove edge; 12. Liquid injection hole; 13. Step surface;

[0033] 20. Seal; 21. Top outer edge; 22. Avoidance groove;

[0034] 30. Weld bead; 31. First region; 32. Second region;

[0035] 40. Sealing pin; 41. Boss portion; 42. Sealing portion. DETAILED DESCRIPTION

[0036] The present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the present application and are not intended to limit the present application. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions of the present application, not all of the structures.

[0037] In the description of this application, unless otherwise expressly specified or limited, the terms "connected," "connected," 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.

[0038] 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.

[0039] 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.

[0040] Example 1

[0041] This embodiment provides a cover plate assembly suitable for use in square batteries. Figure 1 and Figure 2 As shown, the cover assembly includes a cover body 10, a seal 20, a sealing pin (not shown) and a weld 30. A receiving groove 11 is provided on the cover body 10. A liquid injection hole 12 is provided at the center of the bottom of the receiving groove 11, which penetrates the cover body 10. Electrolyte can be injected into the battery through the liquid injection hole 12. The sealing pin is interference-fitted in the liquid injection hole 12, and the circumferential surface of the sealing pin is tightly matched with the hole wall of the liquid injection hole 12 to form a first-level seal; the seal 20 is fixed in the receiving groove 11 by laser welding, thereby forming a second-level seal. A weld 30 is formed between the outer peripheral side wall of the seal 20 and the side wall of the receiving groove 11. The seal 20 is made of the same metal material as the cover body 10, so that the two can be fixedly connected as one by laser welding.

[0042] Furthermore, if Figure 4As shown, the depth h of the weld bead 30 and the thickness z of the seal 20 satisfy: h is greater than or equal to 0.3z. When the depth of the weld bead 30 is too small relative to the thickness of the seal 20, cracks will appear in the weld bead 30 after the vibration test. When the high-temperature storage test is performed later, the top patch of the cracked sample will bulge, and there is a risk of leakage. Therefore, by setting the relationship between the depth of the weld bead 30 and the thickness of the seal 20 within the above range, the above problems can be avoided, the depth and structural strength of the weld bead 30 can be guaranteed, thereby ensuring the sealing reliability of the seal 20, avoiding crack defects, and thus avoiding the risk of leakage. To this end, the applicant conducted relevant tests on the relationship between the depth h of the weld bead 30 and the thickness z of the seal 20 being greater than or equal to 0.3z, that is, 50 test samples (single cells) with a weld bead 30 depth h≥0.3z and a weld bead 30 depth h<0.3z under pulsed laser welding were obtained respectively. A vibration test was first performed to detect the surface morphology of the weld bead 30, and then a high-temperature test was performed to detect whether there was a risk of leakage. Table 1 only shows the relevant data of four samples out of the 100 samples.

[0043] Table 1

[0044] sample Weld bead depth h(μm) Seal thickness z (μm) Is there leakage? A 309.75 1042.12 yes B 286.43 967.32 yes C 730.92 901.17 no D 585.68 890.50 no

[0045] As shown in Table 1, Samples A and B were two of the 50 test samples with h < 0.3z, and Samples C and D were two of the 50 test samples with h ≥ 0.3z. After the vibration test, two samples (Samples A and B) in the test group with h < 0.3z exhibited cracks in weld bead 30, while the test group with h ≥ 0.3z remained normal and crack-free. Both groups of samples were then subjected to a high-temperature storage test. In the test group with h < 0.3z, the top patches of the two cracked samples were bulging, posing a risk of leakage. In the test group with h ≥ 0.3z, the top patches of all samples remained intact, eliminating the risk of leakage.

[0046] In summary, by setting the relationship between the depth of the weld bead 30 and the thickness of the seal 20 to: h is greater than or equal to 0.3z, the depth and structural strength of the weld bead 30 can be ensured, crack defects can be avoided, and the risk of leakage can be avoided.

[0047] Furthermore, based on the above relationship, the depth h of the weld bead 30 and the thickness z of the seal 20 must also satisfy the following relationship: h is less than or equal to 1.5z. For example, the depth h of the weld bead 30 can be 0.3z, 0.6z, 0.9z, 1.2z, or 1.5z. When the depth of the weld bead 30 is too great relative to the thickness of the seal 20, the laser peak power needs to be increased. This increased penetration also leads to increased slag spatter. The slag ejected from the molten pool easily lands on the surfaces of the cover plate body 10 and the seal 20, where it solidifies to form convex slag. This slag not only affects the aesthetic appearance of the cover plate assembly, resulting in a poor appearance, but also can lift the insulating film during the subsequent battery coating process, potentially piercing the film and affecting the battery's insulation performance. Therefore, by setting the relationship between the depth of the weld bead 30 and the thickness of the seal 20 within the above range, the problem of slag spatter caused by excessive heat input can be reduced, thereby minimizing the poor appearance of the cover plate assembly and the impact on the battery's insulation performance.

[0048] To this end, the applicant also conducted tests on the relationship between the depth h of the weld bead 30 and the thickness z of the seal 20, where h is less than or equal to 1.5z. Specifically, 10 test samples (single cells) were obtained and observed for pulsed laser welding with a weld bead 30 depth h ≤ 1.5z and a weld bead 30 depth h > 1.5z. Table 2 shows the relevant data for only 10 of the 20 samples.

[0049] Table 2

[0050] sample Weld bead depth h(μm) Seal thickness z (μm) Whether welding slag is generated A 635.21 932.86 no B 752.36 986.54 no C 734.64 906.32 no D 869.56 964.52 no E 635.28 998.19 no F 1442.26 957.27 yes G 1356.98 899.26 yes H 1429.25 946.91 yes I 1440.2 955.38 yes J 1473.81 975.25 yes

[0051] As shown in Table 2, Samples A through E represent five of the ten test samples with h ≤ 1.5z, and Samples F through J represent five of the ten test samples with h > 1.5z. Observation revealed that weld slag formed in the weld bead 30 of all samples in the test group with h > 1.5z. While weld slag was not normally formed in the test group with h ≤ 1.5z, one or two of the ten samples occasionally produced slag, which is an acceptable level.

[0052] Therefore, by setting the relationship between the depth of the weld bead 30 and the thickness of the seal 20 to: h is less than or equal to 0.3z, the problem of slag splashing caused by excessive heat input can be reduced, thereby reducing the poor appearance of the cover assembly and the impact on the battery insulation performance.

[0053] It should be noted that the depth measurement method of the weld bead 30 is as follows: after the sealing part 20 is welded, it is cut along the center position of the sealing part 20 using a cutting machine, and the cut surface is polished for 1 minute using 800-grit and 200-grit sandpaper respectively. After polishing until there are no obvious scratches on the surface, it is soaked in 5% sodium hydroxide solution for 5 minutes. Finally, the morphology of the molten pool is observed using an ultra-depth of field microscope and the depth of the weld bead 30 is marked.

[0054] Specifically, if Figure 1 and Figure 3 As shown, a gap 100 for welding is formed between the top outer edge 21 of the seal 20 and the top groove edge 111 of the accommodating groove 11. The gap 100 has a dividing line 101 extending along its circumference. Along the radial direction of the seal 20, the distance between the top outer edge 21 and the dividing line 101 is equal to the distance between the top groove edge 111 and the dividing line 101. That is, the dividing line 101 is the center line of the gap 100 in the width direction. The "equal" here does not mean completely equal in a strict sense. The position of the dividing line 101 may also have a slight deviation within the allowable error range. The weld bead 30 is formed between the seal 20 and the cover plate body 10 along the circumference of the gap 100, and the weld bead 30 is symmetrical about the dividing line 101. The "symmetry" here does not mean completely symmetrical in a strict sense. The symmetry axis of the weld bead 30 may have a slight deviation relative to the dividing line 101 within the allowable error range. It should be noted that Figure 3 The width of the gap 100 shown in FIG. 1 is only for ease of understanding, and the actual width of the gap 100 is very small.

[0055] During welding, laser welding is performed along the circumference of gap 100 on the cover plate assembly provided in this embodiment. After welding, a circular weld bead 30 is formed between the seal 20 and the cover plate body 10. This weld bead 30 is nearly symmetrical about the dividing line 101 of gap 100. In other words, welding is performed along the dividing line 101 of gap 100, and the axis of symmetry of the resulting weld bead 30 is nearly aligned with the dividing line 101, thus preventing defects such as weld deviation and cracks. By properly positioning the weld bead 30, cracks are less likely to form at the weld bead 30 after welding, thereby improving the quality of the weld bead 30 and ensuring the sealing reliability of the seal 20.

[0056] In this embodiment, pulse laser welding is used for welding. Pulse laser welding can use pulse laser, which has high peak power, relatively small thermal effect and higher processing precision. To ensure welding quality and work efficiency, the welding speed can be set within the range of 2.0mm / s-10mm / s, and 7.0mm / s is preferred for welding. Figure 3As shown, the cross section of the weld bead 30 formed by pulse laser welding is arc-shaped, with a portion of the weld bead 30 falling on the seal 20 , a portion falling in the gap 100 between the seal 20 and the receiving groove 11 , and a portion falling on the cover plate body 10 .

[0057] It should be noted that there is a clearance fit between the seal 20 and the receiving groove 11. Under ideal conditions, the seal 20 is placed exactly in the middle of the receiving groove 11 before welding, and the gap 100 between the seal 20 and the receiving groove 11 is a regular annular gap. Therefore, after welding, the dividing line 101 of the gap 100 is the symmetry axis of the weld bead 30. However, in actual operation, due to the possible positioning error when the seal 20 is placed in the receiving groove 11, the seal 20 may sometimes not be placed exactly in the center of the receiving groove 11, but may be eccentric to the receiving groove 11. At this time, the gap 100 between the seal 20 and the receiving groove 11 may vary in width. Therefore, in this case, during the welding process, the seal 20 can be slightly offset to the left and right relative to the dividing line 101 in the ideal state, with a movement range of ±0.3 mm, to eliminate the positioning error when the seal 20 is placed and ensure the welding quality.

[0058] In an optional embodiment, if Figure 4 As shown, the thickness z of the seal 20 and the thickness k of the cover body 10 satisfy the following relationship: z is greater than or equal to 0.3k and less than or equal to 0.6k. For example, the thickness z of the seal 20 can be 0.3k, 0.4k, 0.5k, or 0.6k. The thickness of the seal 20 is the depth of the receiving groove 11. By setting the thickness relationship between the seal 20 and the cover body 10 within the above reasonable range, the sealing reliability of the seal 20 is ensured while maintaining the structural strength of the cover body 10.

[0059] In an optional embodiment, the thickness z of the seal 20 can be 0.8mm-1.2mm, and the thickness k of the cover body 10 can be 1.8mm-3.0mm. For example, the thickness z of the seal 20 can be 0.8mm, 0.9mm, 1.0mm, 1.1mm, or 1.2mm, and the thickness k of the cover body 10 can be 1.8mm, 2.0mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, or 3.0mm, as long as z is greater than or equal to 0.3k and less than or equal to 0.6k. By setting the thickness z of the seal 20 and the thickness k of the cover body 10 within the above reasonable ranges, the sealing reliability of the seal 20 is ensured while also ensuring the structural strength of the cover body 10.

[0060] In an optional embodiment, if Figure 1 and Figure 2As shown, the circumferential sidewalls of the receiving groove 11 are inclined surfaces. The diameter of the receiving groove 11 gradually increases along the axial direction of the receiving groove 11 and in a direction gradually away from the injection hole 12. Correspondingly, the outer circumferential sidewalls of the sealing member 20 are inclined surfaces that match the receiving groove 11. Therefore, the inclined surfaces between the sealing member 20 and the receiving groove 11 enhance the sealing effect. In another alternative embodiment, the receiving groove 11 and the sealing member 20 may also be cylindrical, which is not specifically limited here.

[0061] In an optional embodiment, if Figure 1 and Figure 2 As shown, the receiving groove 11 and the liquid injection hole 12 are coaxially arranged. The radial dimension of the receiving groove 11 is larger than the radial dimension of the liquid injection hole 12. Therefore, the receiving groove 11 and the liquid injection hole 12 together form a stepped hole, and a step surface 13 is formed at the connection between the receiving groove 11 and the liquid injection hole 12. The bottom end of the sealing member 20 can abut the step surface 13. The above arrangement can limit the installation of the sealing member 20, so that the top surface of the sealing member 20 can be as flush as possible with the top surface of the cover body 10, ensuring aesthetics, while preventing the sealing member 20 from squeezing the sealing pin 30, ensuring sealing performance. Secondly, the step surface 13 can also support the sealing member 20 during welding, ensuring stable placement of the sealing member 20 and ensuring welding quality.

[0062] In an optional embodiment, if Figure 1 and Figure 2 As shown, the sealing pin 40 includes a connected sealing portion 42 and a boss portion 41. The radial dimension of the boss portion 41 is slightly larger than that of the sealing portion 42. The sealing portion 42 is embedded in the liquid injection hole 12, and the end surface of the boss portion 41 closest to the sealing portion 42 abuts the stepped surface 13. The boss portion 41 acts as a limiter during installation of the sealing pin 40, preventing the sealing pin 40 from being inserted into the liquid injection hole 12 and affecting the sealing performance. The sealing pin 40 is a rubber pin, and the size of the sealing portion 42 is slightly larger than the size of the liquid injection hole 12. The sealing portion 42 forms an interference fit with the liquid injection hole 12 through its own elastic deformation, thereby sealing the liquid injection hole 12.

[0063] like Figure 2 As shown, a avoidance groove 22 is recessed at the center of one side of the seal 20 close to the injection hole 12. The avoidance groove 22 is used to avoid the boss portion 41 of the sealing nail 40. The aperture of the avoidance groove 22 is larger than the aperture of the injection hole 12 and larger than the outer diameter of the boss portion 41. The depth of the avoidance groove 22 is greater than the thickness of the boss portion 41. The avoidance groove 22 can accommodate the boss portion 41, thereby avoiding the boss portion 41 and avoiding interference between the seal 20 and the sealing nail 40, which not only ensures the normal installation of the sealing nail 40, but also ensures the normal installation of the seal 20, ensuring the welding yield and sealing effect.

[0064] In an optional embodiment, if Figure 4As shown, the depth e of the escape groove 22 can be 0.4 mm to 0.6 mm. For example, the depth e of the escape groove 22 can be 0.4 mm, 0.5 mm, or 0.6 mm. By setting the depth of the escape groove 22 within the above reasonable range, the sealing pins can be avoided without affecting the structural strength of the seal 20.

[0065] like Figure 4 As shown, for ease of understanding, the case where the weld bead 30 is completely symmetrical about the dividing line 101 is used as an example for explanation. The widths of the two symmetrical parts of the weld bead 30 about the dividing line 101 are a and b, respectively, and a=b. The width of the weld bead 30 is a+b, which is also the maximum width of the weld bead 30. The horizontal distance from the edge of the avoidance groove 22 to the dividing line 101 is a+d. In an optional embodiment, the width a+b of the weld bead 30 and the horizontal distance a+d from the edge of the avoidance groove 22 to the dividing line 101 satisfy: a+b is greater than or equal to 0.4(a+d) and less than or equal to 1.2(a+d). Exemplarily, the width a+b of the weld bead 30 can be 0.4(a+d), 0.6(a+d), 0.8(a+d), 1.0(a+d), or 1.2(a+d). By setting the relationship between the width a+b of the weld bead 30 and the horizontal distance a+d from the edge of the avoidance groove 22 to the dividing line 101 within the above-mentioned reasonable range, the width and structural strength of the weld bead 30 are guaranteed, avoiding defects such as overmelting and thermal cracks caused by excessive heat input, thereby avoiding the risk of leakage.

[0066] In another optional implementation, the width a+b of the weld bead 30 and the thickness z of the seal 20 may satisfy the following relationship: a+b is greater than or equal to 1.0z and less than or equal to 2.5z. For example, the width a+b of the weld bead 30 may be 1.0z, 1.5z, 2.0z, or 2.5z. By setting the relationship between the width a+b of the weld bead 30 and the thickness z of the seal 20 within the aforementioned reasonable range, the width and structural strength of the weld bead 30 can be maintained, preventing defects such as overmelting and thermal cracking caused by excessive heat input, thereby minimizing the risk of leakage.

[0067] This embodiment also provides a battery cell, comprising a housing, a battery cell, and the aforementioned cover plate assembly. The battery cell is housed within the housing, and the cover plate assembly is mounted on the housing. The battery cell is a prismatic battery. The injection hole 12 on the cover plate body 10 is used to inject electrolyte into the battery, allowing the battery cell to be soaked with the electrolyte. The battery cell in this embodiment, by employing the aforementioned cover plate assembly, can improve the quality of the weld bead 30, ensure the sealing reliability of the power battery, and avoid leakage, thereby extending the service life and improving the safety of the power battery.

[0068] This embodiment also provides an electrical device comprising the aforementioned battery cells. A battery pack composed of multiple battery cells can provide electrical energy to the electrical device. The electrical device can be an electric vehicle, a hybrid electric vehicle, a ship, or other electrical equipment, without specific limitation herein. The electrical device provided in this embodiment, by including the aforementioned battery cells, can avoid leakage and ensure the safety of the electrical device.

[0069] Example 2

[0070] The structure of the cover plate assembly provided in this embodiment is substantially the same as that of the cover plate assembly provided in the first embodiment, and the similarities are not repeated here. The differences are as follows: Figure 5 and Figure 6 As shown, the weld bead 30 includes a first region 31 and a second region 32 in the thickness direction of the cover plate body 10. The first region 31 and the second region 32 have overlapping portions, and the width of the first region 31 is greater than the width of the second region 32, while the depth of the second region 32 is greater than the depth of the first region 31. The axes of symmetry of the first region 31 and the second region 32 both coincide with the dividing line 101 of the gap 100, thus preventing defects such as weld deviation and cracks. By properly positioning and distributing the weld bead 30, cracking is less likely to occur at the weld bead 30 after welding, thereby improving the quality of the weld bead 30 and ensuring the sealing reliability of the seal 20. It should be noted that the aforementioned "the axes of symmetry of the first region 31 and the second region 32 both coincide with the dividing line 101 of the gap 100" does not strictly mean complete overlap, but rather nearly overlap. The axis of symmetry of the weld bead 30 may also deviate slightly from the dividing line 101 within an allowable error range.

[0071] In this embodiment, continuous laser welding is used for welding. Continuous laser welding can use an annular spot laser to reduce spatter and make the welding effect more beautiful. Figure 5 The outer ring laser light generated by the annular spot laser forms the first region 31, and the inner ring laser light generated by the annular spot laser forms the second region 32. The inner ring laser light has higher energy than the outer ring laser light, thereby forming the second region 32 with a greater depth. The first region 31 has a portion overlapping with the upper portion of the second region 32 and has portions located on the left and right sides of the second region 32. The second region 32 has a portion overlapping with the upper portion of the first region 31 and has a portion located below the first region 31.

[0072] It should be noted that, similar to Example 1, in actual operation, due to the positioning error when the seal 20 is placed in the receiving groove 11, the seal 20 may sometimes not be placed exactly in the center of the receiving groove 11, but is eccentrically arranged with respect to the receiving groove 11. The gap 100 between the seal 20 and the receiving groove 11 is an irregular gap, and the gap 100 varies in width. Therefore, in this case, during the welding process, it can be slightly offset to the left and right relative to the ideal dividing line 101, and the movement range is within ±0.2mm, which can eliminate the positioning error when the seal 20 is placed to ensure the welding quality.

[0073] like Figure 6 As shown, the depth of the first region 31 is h1, and the additional depth of the second region 32 is h2. Therefore, the depth h1+h2 of the second region 32 is the maximum depth of the entire weld bead 30. In an optional embodiment, the depth h1+h2 of the second region 32 and the thickness z of the seal 20 satisfy the following relationship: h1+h2 is greater than or equal to 0.3z and less than or equal to 1.5z. For example, the depth h1+h2 of the second region 32 can be 0.3z, 0.6z, 0.9z, 1.2z, or 1.5z. By setting the relationship between the maximum depth of the second region 32 and the thickness of the seal 20 within the above range, the depth and strength of the weld bead 30 can be guaranteed, avoiding defects such as overmelting and thermal cracking caused by excessive heat input.

[0074] In an optional embodiment, the depth h1 of the first region 31 and the depth h1+h2 of the second region 32 satisfy the following relationship: h1 is greater than or equal to 0.2(h1+h2) and less than or equal to 0.6(h1+h2). For example, the depth h1 of the first region 31 may be 0.2(h1+h2), 0.3(h1+h2), 0.4(h1+h2), 0.5(h1+h2), or 0.6(h1+h2). By setting the depth relationship between the first region 31 and the second region 32 within the above-mentioned reasonable range, unnecessary energy loss during welding can be reduced while ensuring the quality of the weld bead 30.

[0075] like Figure 6As shown, for ease of understanding, the case where the weld 30 is completely symmetrical about the dividing line 101 is taken as an example for explanation. The widths of the two symmetrical parts of the second area 32 about the dividing line 101 are m and n, respectively, and m=n, and the width of the second area 32 is m+n; the extra width of one side of the first area 31 than that of one side of the second area 32 is p, and the extra width of the other side of the first area 31 than that of the other side of the second area 32 is q, and p=q. Therefore, the widths of the two symmetrical parts of the first area 31 about the dividing line 101 are m+p and n+q, respectively, and m+p=n+q. The width of the first area 31 is m+n+p+q, which is the maximum width of the entire weld 30, and the horizontal distance from the edge of the avoidance groove 22 to the dividing line 101 is m+p+d.

[0076] In an optional embodiment, the width m+n+p+q of the first region 31 and the horizontal distance m+p+d from the edge of the avoidance groove 22 to the dividing line 101 satisfy the following: m+n+p+q is greater than or equal to 0.4(m+p+d) and less than or equal to 1.2(m+p+d). Exemplarily, the width m+n+p+q of the first region 31 can be 0.4(m+p+d), 0.6(m+p+d), 0.8(m+p+d), 1.0(m+p+d) or 1.2(m+p+d). By setting the relationship between the width m+n+p+q of the first region 31 and the horizontal distance m+p+d from the edge of the avoidance groove 22 to the dividing line 101 within the above-mentioned reasonable range, the width and structural strength of the weld 30 are ensured, and defects such as over-melting and thermal cracking caused by excessive heat input are avoided, thereby avoiding the risk of leakage.

[0077] In another optional embodiment, the width m+n+p+q of the first region 31 may also satisfy the following relationship with the thickness z of the seal 20: m+n+p+q is greater than or equal to 1.0z and less than or equal to 2.5z. For example, the width m+n+p+q of the first region 31 may be 1.0z, 1.5z, 2.0z, or 2.5z. By setting the relationship between the width m+n+p+q of the first region 31 and the thickness z of the seal 20 within the above-mentioned reasonable range, the width and structural strength of the weld bead 30 can also be ensured, avoiding defects such as overmelting and thermal cracking caused by excessive heat input, thereby avoiding the risk of leakage.

[0078] 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. A person skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present application. 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. Cover plate assembly, characterized in that, include: A cover plate body (10) is provided with a receiving groove (11), and a liquid injection hole (12) penetrating the cover plate body (10) is provided at the bottom of the receiving groove (11); A sealing member (20) is disposed in the receiving groove (11), a weld bead (30) is formed between the outer peripheral side wall of the sealing member (20) and the side wall of the receiving groove (11), and the depth h of the weld bead (30) and the thickness z of the sealing member (20) satisfy: h is greater than or equal to 0.3z.

2. The cover plate assembly according to claim 1, wherein: The depth h of the weld bead (30) and the thickness z of the sealing member (20) also satisfy the following: h is less than or equal to 1.5z.

3. The cover plate assembly according to claim 1, wherein: The receiving groove (11) is coaxially arranged with the liquid injection hole (12); the radial dimension of the receiving groove (11) is larger than the radial dimension of the liquid injection hole (12); a step surface (13) is formed at the connection between the receiving groove (11) and the liquid injection hole (12); and the bottom end of the sealing member (20) can abut against the step surface (13).

4. The cover plate assembly according to claim 3, wherein: The cover plate assembly further comprises a sealing pin (40) which is interference-fitted in the liquid injection hole (12); a side of the sealing member (20) close to the liquid injection hole (12) is provided with an escape groove (22) for evading the sealing pin (40).

5. The cover plate assembly according to claim 4, wherein: The radial dimension of the avoidance groove (22) is greater than the radial dimension of the liquid injection hole (12).

6. The cover plate assembly according to claim 5, wherein: The sealing pin (40) includes a sealing portion (42) and a boss portion (41) connected to each other. The radial dimension of the boss portion (41) is larger than the radial dimension of the sealing portion (42). The sealing portion (42) is embedded in the liquid injection hole (12). An end surface of the boss portion (41) close to the sealing portion (42) abuts against the step surface (13). The avoidance groove (22) is used to avoid the boss portion (41).

7. The cover plate assembly according to any one of claims 1 to 6, characterized in that: The circumferential side wall of the receiving groove (11) is an inclined surface, and the diameter of the receiving groove (11) gradually increases in the direction along the axial direction of the receiving groove (11) and gradually away from the injection hole (12). The outer circumferential side wall of the sealing member (20) is an inclined surface adapted to the receiving groove (11).

8. The cover plate assembly according to any one of claims 1 to 6, characterized in that: The weld bead (30) includes a first region (31) and a second region (32) along the thickness direction of the cover plate body (10), wherein the width of the first region (31) is greater than the width of the second region (32), and the depth of the second region (32) is greater than the depth of the first region (31).

9. A battery cell, characterized in that The invention comprises a cover plate assembly according to any one of claims 1 to 8.

10. Electrical equipment, characterized in that: Comprising the battery cell according to claim 9.

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