Weld joint leakage point maintenance method applied to battery monomer production and battery monomer

Abstract

The embodiment of the invention provides a welding seam leakage point overhauling method and equipment applied to battery monomer production and a battery monomer. The welding seam leakage point overhauling method comprises the steps that the containing cavity is vacuumized through the liquid injection hole; helium is injected into the vacuumized containing cavity through the liquid injection hole; a muzzle of a suction gun of the helium mass spectrometer leak detector is close to the welding seam and surrounds the welding seam by a circle, and in the operation process, if detection data of the helium mass spectrometer leak detector is larger than a preset value, it is determined that leakage points exist in the welding seam; and performing repair welding on the welding seam to form a repair welding seam covering the leakage point. According to the scheme of the embodiment of the invention, the success rate and efficiency of weld leakage point maintenance in the production of the battery monomer can be improved.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the technical field of battery production, and in particular to a method and device for repairing weld leaks used in battery cell production, and a battery cell. Background Art

[0002] With the rapid development of the battery industry in recent years, the requirements for battery production efficiency and quality have become increasingly stringent. In the battery production process, welding, as a commonly used production process, has an extremely important impact on battery production efficiency and product quality.

[0003] A battery cell is the smallest unit in a battery that provides an energy source. The main structure of a battery cell generally includes a shell and a cover that enclose a receiving cavity, a cell assembly disposed in the receiving cavity, a pole disposed in the cover, and an electrolyte filled in the receiving cavity through an injection hole on the cover. When manufacturing a battery cell, the cell assembly is first placed in the shell, and then the cover is welded to the shell to achieve a sealed connection through the weld, and then the electrolyte is injected into the receiving cavity through the injection hole on the cover, and then the injection hole is blocked by a blocking structure.

[0004] The welding quality between the cover and the shell is the key to determining the production yield of the product. Weld leaks are a common defect that leads to poor product quality. Once missed, it is likely to cause electrolyte leakage and even cause safety accidents. Therefore, how to improve the success rate and efficiency of repairing weld leaks in battery cell production is a technical problem that technicians in this field need to solve urgently. Summary of the invention

[0005] The embodiments of the present disclosure provide a weld leak inspection method and device and a battery cell used in battery cell production to improve the success rate and efficiency of weld leak inspection.

[0006] According to one aspect of the present disclosure, a method for repairing weld leaks used in battery cell production is provided. The battery cell comprises a shell and a cover body welded to each other to enclose a receiving cavity, the cover body having a liquid injection hole, and the method for repairing weld leaks comprises: evacuating the receiving cavity through the liquid injection hole; injecting helium into the evacuated receiving cavity through the liquid injection hole; placing the muzzle of a suction gun of a helium mass spectrometer leak detector close to the weld and surrounding the weld, during this operation, if the detection data of the helium mass spectrometer leak detector is greater than a preset value, it is determined that a leak exists in the weld; and repairing the weld to form a repair weld covering the leak.

[0007] In some embodiments, the weld leak inspection method also includes: before evacuating the containing cavity through the liquid injection hole, dividing the weld of the shell and the cover into a plurality of inspection segments, wherein the length of each inspection segment is not greater than 20 mm; wherein, determining whether the weld has a leak includes: determining the segment to be repaired where the leak exists.

[0008] In some embodiments, the repair weld covers the segment to be repaired, and the length of the repair weld is no more than 20 mm.

[0009] In some embodiments, the movement rate of the gun muzzle relative to the weld is not less than 5 mm / sec and not more than 25 mm / sec.

[0010] In some embodiments, the angle between the axial direction of the gun muzzle and the weld is not less than 90 degrees and not more than 180 degrees.

[0011] In some embodiments, the width of the repair weld is not less than 1.0 mm and not more than 1.5 mm; or, the width ratio of the repair weld to the weld is not less than 10 / 9 and not more than 5 / 3.

[0012] In some embodiments, the weld leak repair method further includes: before evacuating the accommodating cavity through the liquid injection hole, placing the battery cell in the accommodating bottom groove, aligning and fitting the jig pressure plate with the cover body, wherein the jig pressure plate is provided with a sealing glue nozzle, the sealing glue nozzle is sealed and connected to the liquid injection hole, and the sealing glue nozzle can be connected to the vacuum device and the helium filling device of the helium mass spectrometer leak detector respectively.

[0013] In some embodiments, evacuating the containing chamber through the liquid injection hole includes: evacuating the containing chamber through the liquid injection hole until the pressure in the containing chamber is not less than -95 kPa and not more than -75 kPa.

[0014] In some embodiments, injecting helium into the vacuumed containing chamber through the injection hole includes: injecting helium into the vacuumed containing chamber through the injection hole until the pressure in the containing chamber is not less than 20 kPa and not more than 60 kPa.

[0015] The weld leak repair method according to any embodiment of the present disclosure can improve the success rate and efficiency of weld leak repair. Moreover, since the length of the repair weld is relatively short, more accurate repair welding can be achieved. In this way, the repair welding time can be reduced and the welding cost can be saved. Other defects caused by repair welding, such as burst points, weld penetration or edge collapse, can also be minimized, thereby improving the production yield of battery cells.

[0016] According to one aspect of the present disclosure, a battery cell is provided, which includes a shell and a cover body welded to each other to enclose a accommodating cavity, a battery cell assembly arranged in the accommodating cavity, and a pole arranged on the cover body, wherein the pole is electrically connected to the battery cell assembly, the cover body has a liquid injection hole, and the weld between the cover body and the shell body includes an original weld and a repair weld obtained according to the aforementioned weld leak repair method.

[0017] In some embodiments, the total length of the at least one repair weld is less than the length of the original weld.

[0018] In some embodiments, the shell has a flange, and the cover is welded to the flange.

[0019] According to the battery cell of this embodiment of the present disclosure, the weld between its cover and shell includes the original weld and the repair weld. The total length of the repair weld is relatively short, and more precise repair welding can be achieved. In this way, the repair welding time can be reduced and the welding cost can be saved, and other defects caused by repair welding, such as burst points, weld penetration or edge collapse, can be minimized, thereby having a higher production yield.

[0020] According to one aspect of the present disclosure, there is provided a weld leak inspection and repair device used in battery cell production, comprising: a helium mass spectrometer leak detector, comprising a vacuum pumping device and a helium filling device; a receiving bottom groove, used to receive the battery cell; a fixture pressing plate, used to align and fit with a cover body of the battery cell placed in the receiving bottom groove, wherein the fixture pressing plate is provided with a sealing glue nozzle, which can be sealed and connected with a liquid injection hole on the cover body, and the sealing glue nozzle can be connected to the vacuum pumping device and the helium filling device respectively; and a welding gun, based on the weld leak inspection and repair method of the aforementioned embodiment, the welding gun can be used to repair the weld to form a repair weld covering the leak.

[0021] The use of the above-mentioned weld leak inspection equipment can not only reduce the repair welding time and save welding costs, but also minimize other defects caused by repair welding, such as burst points, weld penetration or edge collapse, thereby achieving a higher production yield rate.

[0022] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings exemplarily illustrate the embodiments and constitute a part of the specification, and together with the text description of the specification, are used to explain the exemplary implementation of the embodiments. The embodiments shown are for illustrative purposes only and do not limit the scope of the claims. In all drawings, the same reference numerals refer to similar but not necessarily identical elements.

[0024] Figure 1It is a schematic diagram of a flow chart of a method for repairing a weld leak according to some embodiments of the present disclosure;

[0025] Figure 2 A schematic diagram of performing weld leak repair according to some embodiments of the present disclosure;

[0026] Figure 3 A schematic diagram comparing an unrepaired weld, a repaired weld obtained by using a related technology, and a repaired weld obtained by a weld leak repair method according to some embodiments of the present disclosure;

[0027] Figure 4 is a schematic diagram of a battery cell according to some embodiments of the present disclosure.

[0028] Reference numerals:

[0029] 100-Weld repair method;

[0030] S1 to S4 - steps;

[0031] 30-battery cell;

[0032] 31-housing;

[0033] 311-flange;

[0034] 32-cover body;

[0035] 35-Pole

[0036] 321- injection hole;

[0037] 33-battery cell assembly;

[0038] 034,34-weld;

[0039] 340-section to be repaired;

[0040] 0341,341-Repair welding;

[0041] 344-Leakage Point

[0042] 500-Helium mass spectrometer leak detector;

[0043] 51- vacuum device;

[0044] 52- helium filling device;

[0045] 53-Suction gun;

[0046] 54-pressure gauge;

[0047] 55-display screen;

[0048] 56-pipeline;

[0049] 41-accommodating bottom groove;

[0050] 42-jig pressure plate;

[0051] 420-Sealing nozzle. DETAILED DESCRIPTION

[0052] The following is a description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, including various details of the embodiments of the present disclosure to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope of the present disclosure. Similarly, for the sake of clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0053] In the present disclosure, unless otherwise specified, the use of the terms "first", "second", etc. to describe various elements is not intended to limit the positional relationship, temporal relationship, or importance relationship of these elements, and such terms are only used to distinguish one element from another element. In some examples, the first element and the second element may refer to the same instance of the element, and in some cases, based on the description of the context, they may also refer to different instances.

[0054] The terms used in the description of various examples in this disclosure are only for the purpose of describing specific examples and are not intended to be limiting. Unless the context clearly indicates otherwise, if the number of elements is not specifically limited, the element can be one or more. In addition, the term "and / or" used in this disclosure covers any one of the listed items and all possible combinations.

[0055] During the production of battery cells, after the cover and the shell are welded, and before the electrolyte is injected through the injection hole on the cover, it is generally necessary to inspect the quality of the weld between the cover and the shell. The welding quality between the cover and the shell is the key to determining the production yield of the product. Weld leaks are a common defect that leads to poor product quality. Missed inspection is likely to cause electrolyte leakage and even cause safety accidents.

[0056] In some related technologies, the detection of weld leaks between the cover and the shell relies on manual visual inspection. When a leak is detected, the leak location is manually marked, and then repair welding is performed at the leak location and its vicinity. In some maintenance scenarios, in order to make the repair weld cover the leak, the length of the repair weld is about 30 mm.

[0057] The technical defects of the above-mentioned related technologies are that the detection of weld leaks relies on manual visual inspection, and the accuracy and efficiency of the detection are not high; in order to make the repair weld cover the leak, the length of the repair weld is usually longer, which is likely to cause other defects due to the repair welding, such as burst points, weld penetration or edge collapse. Explosion points usually appear as small pits or protrusions, which not only affect the air tightness of the weld, but also affect the strength of the weld, reduce the weld burst pressure and breathing fatigue strength. Weld penetration generally refers to the defect of molten metal flowing out from the back of the groove to form a perforation. After the weld is penetrated, it can usually only be scrapped, which will seriously affect the production yield. Collapse refers to the failure of the solder to maintain its original shape when heated, resulting in collapse, which will seriously affect the strength of the weld.

[0058] In view of this, the embodiments of the present disclosure provide a weld leak inspection method and device and a battery cell used in battery cell production to improve the success rate and efficiency of weld leak inspection. The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0059] like Figure 1 and Figure 2 As shown, Figure 1 1 is a flow chart of a weld leak repair method 100 according to some embodiments of the present disclosure. Figure 2 Schematic diagram of repairing weld leaks according to some embodiments of the present disclosure. Some embodiments of the present disclosure provide a weld leak repair method 100 for battery cell production, such as Figure 2 As shown, the battery cell 30 may include a shell 31 and a cover 32 which are welded to each other to enclose a receiving cavity, and the cover 32 has a liquid injection hole 321. The weld leak repair method 100 may include the following steps S1 to S4.

[0060] In step S1 , the containing chamber is evacuated through the injection hole 321 .

[0061] In step S2 , helium is injected into the evacuated containing chamber through the injection hole 321 .

[0062] In step S3, the muzzle of the suction gun 53 of the helium mass spectrometer leak detector 500 is placed close to the weld 34 and circles the weld 34. During this operation, if the detection data of the helium mass spectrometer leak detector 500 is greater than a preset value, it is determined that there is a leak in the weld.

[0063] In step S4, refer to Figure 3 As shown, the weld is repaired to form a repair weld 341 covering the leak point 344 .

[0064] Helium mass spectrometer leak detector is an airtightness detection instrument made according to the principle of mass spectrometry, using helium as the leak indicator gas. Helium mass spectrometer leak detector is generally composed of a mass spectrometer chamber composed of an ion source, an analyzer, a collector, a cold cathode ionization gauge, an exhaust system and electrical parts. The basic working principle of helium mass spectrometer leak detector is that the electrons emitted by the filament in the mass spectrometer chamber oscillate back and forth in the chamber, and collide with the indoor gas and the helium entering the chamber through the leak hole to ionize them into positive ions. These helium ions enter the magnetic field under the action of the accelerating electric field, and are deflected by the Lorentz force to form a circular arc orbit. Changing the acceleration voltage can make ions of different masses pass through the magnetic field and the receiving slit to reach the receiving electrode and be detected. The helium absorption method is a commonly used detection method for helium mass spectrometer leak detectors. The principle is to fill the container to be tested with helium, equip the leak detection port of the helium mass spectrometer with a special suction gun, and move the suction gun towards the welds and sealing joints of the container to be tested filled with helium. If the container has a leak, the helium that leaks through the leak will be sucked in, and the helium mass spectrometer leak detector will respond accordingly.

[0065] According to the weld leak inspection method 100 of the embodiment of the present disclosure, in step S3, the muzzle of the suction gun 53 of the helium mass spectrometer leak detector 500 is placed close to the weld 34 and surrounds the weld 34 for one circle. During this operation, if the detection data of the helium mass spectrometer leak detector 500 is greater than a preset value, it is determined that there is a leak in the weld, and the approximate location of the leak can be determined accordingly; in step S4, refer to Figure 3 As shown, the weld is repaired to form a repair weld 341 covering the leak 344. Therefore, the weld leak inspection method 100 of the disclosed embodiment can improve the success rate and efficiency of weld leak inspection, and the length of the formed repair weld 341 is relatively short, which can achieve more accurate repair welding, so that it can reduce the repair welding time and save welding costs, and can also minimize other defects caused by repair welding, such as explosion points, welding penetration or edge collapse, etc., so as to improve the production yield of the battery cell 30.

[0066] like Figure 3 As shown, it is a schematic comparison of the appearance of the unrepaired weld 034, the repaired weld 0341 obtained by using the aforementioned related technology, and the repaired weld 341 obtained according to the embodiment of the present disclosure. It can be seen that the length of the repaired weld 341 obtained according to the embodiment of the present disclosure is significantly smaller than that of the related technology, wherein the repaired weld 341 and the weld 31 can completely overlap in width or overlap within the error range.

[0067] In some comparative examples of the present disclosure, for some weld inspection scenarios, although it can be determined that there are leaks in the weld, the location of the leak cannot be determined, and it cannot be observed by manual visual inspection. Therefore, in order to make the repair weld cover the leak, the entire weld is usually re-welded, resulting in the length of the repair weld being approximately equal to the length of the entire weld, such as about 1400 mm. Compared with this comparative example, the size of the repair weld obtained by the weld leak inspection method 100 according to the embodiment of the present disclosure is significantly smaller, so it can greatly reduce the defects such as burst points, weld penetration or edge collapse caused by repair welding.

[0068] In some embodiments of the present application, the weld leak inspection method may further include: before step S1, the welds of the shell and the cover are divided into a plurality of inspection segments, wherein the length of each inspection segment is not greater than 20 mm, the inspection length matches the subsequent repair welding length, and since the diameter of the suction gun probe is small, the inspection length of each segment is not easy to be too small; if the inspection length of each segment is too long, the required repair welding length becomes longer, the repair welding trace is more obvious, and it is easy to cause repair welding explosion points, welding penetration, and collapsed edges. According to this embodiment, in step S3, if the detection data of the helium mass spectrometer leak detector 500 is greater than the preset value, it is determined that the current inspection segment opposite to the muzzle is a segment to be repaired with a leak, and the segment to be repaired can be determined accordingly; in step S4, the segment to be repaired 340 with a leak 344 can be repaired, and the formed repair weld 341 covers the segment to be repaired 340, so that the leak 344 can be fully covered.

[0069] According to the weld leak inspection method 100 of these embodiments, the segment 340 to be repaired with a leak 344 can be quickly located, thereby reducing the time for inspection and repair welding and saving welding costs. In some embodiments, the length of the repair weld is no more than 20 mm, and the repair size is small, which can reduce the explosion point, weld penetration, and edge collapse caused by repair welding.

[0070] The weld leak inspection method 100 of the disclosed embodiment can be implemented by a helium mass spectrometer leak detector 500 and related jigs.

[0071] like Figure 2 As shown, in some embodiments, the helium mass spectrometer leak detector 500 may mainly include a mass spectrometer chamber (not shown in the figure), a vacuum pumping device 51, a helium filling device 52, related pipelines 56, a pressure gauge 54 and a display screen 55, etc., wherein the display screen 55 can display the monitored related data, such as vacuum pumping pressure, helium injection pressure, mass spectrometer detection values, etc. Figure 2 The helium mass spectrometer leak detector 500 shown in the figure is only a schematic diagram of its basic structure, and the embodiment of the present disclosure does not specifically limit its specific product specifications and types.

[0072] like Figure 2As shown, in some embodiments, the jig may include a bottom groove 41 for accommodating the battery cell 30 and a jig pressing plate 42 for aligning and fitting with the cover body 32 of the battery cell 30. The jig pressing plate 42 is provided with a sealing glue nozzle 420. The sealing glue nozzle 420 can be connected to the vacuum device 51 and the helium filling device 52 of the helium mass spectrometer leak detector 500 respectively. When the jig pressing plate 42 is aligned and fitted with the cover body 32, the sealing glue nozzle 420 is sealed and connected with the injection hole 321.

[0073] Based on the above jig design, in some embodiments of the present disclosure, the weld leak repair method 100 may further include: before the above step S1, placing the battery cell 30 in the receiving bottom groove 41, and aligning and fitting the jig pressing plate 42 with the cover body 32, wherein the jig pressing plate 42 is provided with a sealing glue nozzle 420, the sealing glue nozzle 420 is sealed and connected with the injection hole 321, and the sealing glue nozzle 420 can be respectively connected to the vacuum device 51 and the helium filling device 52 of the helium mass spectrometer leak detector 500. Using the jig pressing plate 42 can improve the convenience of operation and the sealing of the connection at the injection hole 321.

[0074] In some embodiments of the present disclosure, the above step S1 includes: evacuating the accommodating chamber through the injection hole 321 until the pressure in the accommodating chamber is not less than -95 kPa and not more than -75 kPa, for example, the pressure in the accommodating chamber reaches -80 kPa. The pressure monitoring data of the pressure gauge 54 can be observed during the evacuation process, and the evacuation is stopped when the pressure reaches -80 kPa. In some embodiments, the evacuation device 51 can automatically stop evacuating when the pressure reaches -80 kPa according to the user's setting.

[0075] In some embodiments of the present disclosure, the above step S2 includes: injecting helium into the evacuated accommodation chamber through the injection hole 321 until the pressure in the accommodation chamber is not less than 20 kPa and not more than 60, for example, the pressure in the accommodation chamber reaches 88 kPa. The pressure monitoring data of the pressure gauge 54 can be observed during the helium injection process, and helium filling is stopped when the pressure reaches 88 kPa. In some embodiments, the helium filling device 52 can also automatically stop helium filling when the pressure reaches 88 kPa according to user settings.

[0076] In some embodiments of the present disclosure, the moving speed of the gun muzzle relative to the weld is not less than 5 mm / s and not more than 25 mm / s. An appropriate moving speed of the gun muzzle can reduce the probability of missed detection and also facilitate improving the operating accuracy of the operator.

[0077] In some embodiments of the present disclosure, the angle between the axial direction of the gun muzzle and the weld 34 is not less than 90 degrees and not greater than 180 degrees. Since the leak point may be on the surface or side of the weld, the axial direction of the gun muzzle and the weld are in an appropriate angle range, which can take into account the detection of the surface or side of the weld on the one hand, and on the other hand, the helium leaked from the leak point can be more smoothly sucked into the suction gun 53, which is conducive to reducing the probability of missed detection and facilitating the improvement of the operator's operating accuracy.

[0078] In some embodiments of the present disclosure, the width of the repair weld is not less than 1.0 mm and not more than 1.5 mm, or the width ratio of the repair weld to the weld is not less than 10 / 9 and not more than 5 / 3. An appropriate repair weld width can not only fully cover the leak point, but also minimize other defects caused by the repair weld, and the appearance of the weld is also more beautiful.

[0079] like Figure 4 As shown, some embodiments of the present disclosure further provide a battery cell 30, which includes a shell 31 and a cover 32 welded to each other to enclose a receiving cavity, a battery cell assembly 33 disposed in the receiving cavity, and a pole 35 disposed on the cover, wherein the pole 35 is electrically connected to the battery cell assembly 33, the cover 32 has a liquid injection hole 321, and a weld 34 between the cover 32 and the shell 31 includes an original weld and a repair weld 341 obtained according to the aforementioned weld leak repair method 100 (for example, Figure 3 ).

[0080] The battery cell 30 of this embodiment of the present disclosure has a weld seam between the cover 32 and the shell 31 including a repair weld seam. Since the length of the repair weld seam is relatively short, a relatively accurate repair weld can be achieved, which can not only reduce the repair weld time and save welding costs, but also minimize other defects caused by repair welds, such as burst points, weld penetration or edge collapse, thereby having a higher production yield. In some embodiments of the present application, the total length of the repair weld seam is less than the length of the original weld seam, so that the welding quality of the shell 31 and the cover 32 is higher, the welding defects are less, and the appearance of the weld seam is more beautiful.

[0081] like Figure 4 As shown, in some embodiments, the housing 31 has a flange 311, and the cover 32 is welded to the flange 311. When the housing 31 and the cover 32 of the battery cell 30 are manufactured, the two can have a relatively wide overlap width. After the initial welding is completed, the redundant edges of the overlap can be cut off, and the above-mentioned weld leak inspection method 100 can be performed thereafter.

[0082] The embodiments of the present disclosure do not limit the specific product type of the battery cell 30, and may be, for example, a lithium cobalt oxide battery cell, a polymer lithium ion battery cell, a lithium-ferrous sulfide battery cell, a lithium iron manganese phosphate battery cell, or a high manganese iron lithium battery cell, etc. In some embodiments, the battery cell 30 is a high manganese iron lithium OS (one-stop) battery cell.

[0083] Some embodiments of the present disclosure also provide a weld leak inspection device used in battery monomer production, referring to Figure 2 As shown, it may include the aforementioned helium mass spectrometer leak detector 500, a receiving bottom groove 41, a jig pressing plate 42 and a welding gun (not shown in the accompanying drawings). The helium mass spectrometer leak detector 500 includes a vacuum pumping device 51 and a helium filling device 52. The receiving bottom groove 41 is used to accommodate the battery cell 30. The jig pressing plate 42 is used to align and fit with the cover body 32 of the battery cell 30 placed in the receiving bottom groove 41, wherein the jig pressing plate 42 is provided with a sealing glue nozzle 420, and the sealing glue nozzle 420 can be sealed and connected with the injection hole 321 on the cover body 32, and the sealing glue nozzle 420 can be connected to the vacuum pumping device 51 and the helium filling device 52 respectively. The operator operates the welding gun and can repair the weld based on the weld leak repair method 100 of the aforementioned embodiment to form a repair weld covering the leak.

[0084] The use of the above-mentioned weld leak inspection equipment can not only reduce the repair welding time and save welding costs, but also minimize other defects caused by repair welding, such as burst points, weld penetration or edge collapse, thereby achieving a higher production yield rate.

[0085] Although the embodiments or examples of the present disclosure have been described with reference to the accompanying drawings, it should be understood that the above-mentioned methods, systems and devices are merely exemplary embodiments or examples, and the scope of the present invention is not limited by these embodiments or examples, but only by the claims after authorization and their equivalent scope. Various elements in the embodiments or examples can be omitted or replaced by their equivalent elements. In addition, each step can be performed in an order different from that described in the present disclosure. Further, the various elements in the embodiments or examples can be combined in various ways. It is important that with the evolution of technology, many elements described herein can be replaced by equivalent elements that appear after the present disclosure.

Claims

1. A method for inspecting and repairing weld leaks in battery cell production, wherein the battery cell comprises a shell and a cover body welded to each other to enclose a receiving cavity, wherein the cover body has a liquid injection hole, characterized in that: The weld leak inspection method comprises: Vacuuming the containing chamber through the injection hole; Inject helium into the evacuated containing cavity through the injection hole; Place the muzzle of the helium mass spectrometer leak detector close to the weld and circle the weld. During this operation, if the detection data of the helium mass spectrometer leak detector is greater than a preset value, it is determined that there is a leak in the weld; and The weld is repaired to form a repair weld covering the leak.

2. The weld leak repair method according to claim 1, characterized in that: The weld leak inspection method further includes: before evacuating the accommodation cavity through the liquid injection hole, dividing the weld of the shell and the cover into a plurality of inspection segments, wherein the length of each inspection segment is not greater than 20 mm; Determine if there are leaks in the weld, including: determine the sections to be repaired with welds that have leaks.

3. The weld leak repair method according to claim 2, characterized in that: The repair weld covers the section to be repaired, and the length of the repair weld is not more than 20 mm.

4. The weld leak repair method according to claim 1, characterized in that: The movement rate of the gun muzzle relative to the weld shall not be less than 5 mm / s and not more than 25 mm / s.

5. The weld leak repair method according to claim 1, characterized in that: The angle between the axial direction of the gun muzzle and the weld shall not be less than 90 degrees and not more than 180 degrees.

6. The weld leak repair method according to claim 1, characterized in that: The width of the repair weld is not less than 1.0 mm and not more than 1.5 mm; or The width ratio of the repair weld to the weld shall not be less than 10 / 9 and not more than 5 / 3.

7. The method for repairing weld leaks according to any one of claims 1 to 6, characterized in that: Also includes: Before the accommodating cavity is evacuated through the injection hole, the battery cell is placed in the accommodating bottom groove, and the jig pressing plate is aligned and fitted with the cover body, wherein: The fixture pressing plate is provided with a sealing glue nozzle, which is sealed and connected with the liquid injection hole, and the sealing glue nozzle can be connected with a vacuum pumping device and a helium filling device of the helium mass spectrometer leak detector respectively.

8. The method for repairing weld leaks according to any one of claims 1 to 6, characterized in that: The containing chamber is evacuated through the injection hole, including: The containing chamber is evacuated through the injection hole until the pressure inside the containing chamber is not less than -95 kPa and not more than -75 kPa.

9. The method for repairing weld leaks according to any one of claims 1 to 6, characterized in that: Injecting helium into the evacuated containing chamber through the injection hole includes: Helium is injected into the evacuated containing chamber through the injection hole until the pressure inside the containing chamber is not less than 20 kPa and not more than 60 kPa.

10. A battery cell, characterized in that: It includes a shell and a cover body welded to each other to enclose a accommodating cavity, a battery cell assembly arranged in the accommodating cavity, and a pole arranged on the cover body, wherein the pole is electrically connected to the battery cell assembly, the cover body has a liquid injection hole, and the weld between the cover body and the shell body includes an original weld and at least one repair weld obtained according to the weld leak repair method of any one of claims 1 to 9.

11. The battery cell according to claim 10, characterized in that: The total length of the at least one repair weld is less than the length of the original weld.

12. The battery cell according to claim 10 or 11, characterized in that: The shell body is provided with a flange, and the cover body is welded to the flange.

13. A weld leak inspection device used in battery monomer production, characterized in that: include: Helium mass spectrometer leak detector, including a vacuum pumping device and a helium filling device; A receiving bottom groove for receiving a battery cell; A jig pressing plate, used for aligning and fitting with the cover of the battery cell placed in the bottom groove, wherein the jig pressing plate is provided with a sealing glue nozzle, which can be sealed and connected with the injection hole on the cover, and the sealing glue nozzle can be connected with the vacuum device and the helium filling device respectively; and A welding gun, wherein, based on the weld leak repair method according to any one of claims 1 to 9, the weld is repaired by using the welding gun to form a repair weld covering the leak.

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