Sealing assembly, sealing and helium detection method and application

Abstract

The invention provides a sealing assembly, a sealing and helium detection method and application. The sealing nail and the sealing rubber nail are sequentially arranged in the electrolyte injection passage along the injection direction of the electrolyte, and an accommodating space for accommodating detection gas is formed between the sealing nail and the sealing rubber nail. According to the sealing assembly provided by the invention, the accommodating space for accommodating the detection gas is formed between the sealing nail and the sealing rubber nail, and during helium detection, helium in the accommodating space is released, so that the welding effect of the sealing nail can be accurately known, the accuracy of helium detection is improved, and the safety performance of a battery is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries and relates to a sealing component, a sealing and helium detection method and an application thereof. Background Art

[0002] At present, in the new energy industry, power batteries and energy storage batteries are rising rapidly, and electric vehicles have also occupied a large market in the automotive industry. Consumers now mainly consider two aspects when choosing electric vehicles. The first is the safety performance of the battery, and the second is the range. In the manufacturing process of lithium batteries, there is a very critical process, sealing welding, which is the final seal of the battery, and its sealing directly affects the safety and electrical performance of the battery.

[0003] The existing square aluminum shells, blade batteries, large cylindrical batteries and other sealing pins need to be tested for air tightness after welding. The existing method is to conduct a secondary helium test after the sealing pins are welded to identify the welding effect.

[0004] Specifically, the prior art is to seal the helium inside the battery with glue nails, and then seal the battery with sealing nails.

[0005] Sealing pin welding is the final seal for the battery. After the sealing pin is welded, the sealing position is tested for air tightness. Since there is a glue pin at the filling port to seal the helium inside the battery, the helium cannot pass through the glue pin during the helium test after welding. Therefore, the effect of sealing pin welding cannot be accurately tested. If the welding is not done well, the leakage cannot be detected at this time. When the sealing pin is loosened or the electrolyte penetrates after the battery has been used for a period of time, battery safety problems will occur. Summary of the invention

[0006] After research, it was found that for the existing helium detection method, helium is sealed inside the battery cell by glue nails. Due to the interference fit between the glue nails and the wall of the injection hole, helium cannot pass through the glue nails during helium detection after welding, so the effect of sealing nail welding cannot be accurately tested. If the welding is not done well, leakage cannot be detected at this time. When the sealing nails loosen or electrolyte penetrates after the battery has been used for a period of time, battery safety problems will occur.

[0007] In view of the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a sealing assembly, a sealing and helium detection method and application. In the sealing assembly provided by the present invention, there is a containing space for accommodating the detection gas between the sealing nail and the sealing glue nail. When the helium detection is performed, the helium therein is released, and the welding effect of the sealing nail can be accurately known, thereby improving the accuracy of the helium detection and further improving the safety performance of the battery.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a sealing assembly, comprising a sealing pin and a sealing glue pin, wherein the sealing pin and the sealing glue pin are sequentially arranged in an injection passage along an injection direction of an electrolyte, and an accommodating space for accommodating a detection gas is provided between the sealing pin and the sealing glue pin.

[0010] The sealing assembly provided by the present invention has a containing space for accommodating detection gas between the sealing pin and the sealing glue pin. When the helium test is performed, the helium therein is released, and the welding effect of the sealing pin can be accurately known, thereby improving the accuracy of the helium test and further improving the safety performance of the battery.

[0011] Preferably, the sealing assembly further comprises a capsule containing a detection gas, and the capsule is placed in the accommodating space.

[0012] Preferably, the sealing nail comprises an upper end surface arranged opposite to the lower end surface of the sealing nail, and the upper end surface of the sealing nail and the lower end surface of the sealing nail together form the accommodating space.

[0013] Alternatively, the upper end surface of the sealing glue nail, the lower end surface of the sealing nail and the inner wall of the liquid injection passage together form the accommodating space.

[0014] Preferably, a concave cavity is provided on the surface of the sealing glue pin facing the sealing pin, the bottom surface of the concave cavity constitutes an upper end surface arranged opposite to the sealing pin, and the concave cavity is used for placing a capsule storing the detection gas.

[0015] Preferably, the depth of the cavity is 0.6-0.9 mm, such as 0.6 mm, 0.7 mm, 0.8 mm or 0.9 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0016] In the present invention, if the depth of the cavity is too shallow, the volume of the accommodating space is too small, and the pressure when the helium is released will push the sealant nail away from the pre-assembly aspect, affecting the subsequent sealing. If the depth is too deep, a longer injection passage is required, that is, the shell needs to be thickened, which increases the weight and cost of the battery cell.

[0017] Preferably, the sealing nail comprises a guiding outer peripheral surface with an outer diameter continuously decreasing along the injection direction of the electrolyte.

[0018] The sealing glue nail provided by the present invention has a guide outer peripheral surface and a bottom (a lower end surface relative to an upper end surface) of the density glue nail to form a conical chamfer.

[0019] In the present invention, the setting of the conical chamfer plays a guiding role when the sealant nail is driven into the nail, so that the sealant nail can enter the position of the injection hole easily.

[0020] In a second aspect, the present invention provides a battery top cover, the battery top cover comprising a liquid injection hole connecting the battery inner cavity and the outside; the liquid injection hole is provided with a sealing assembly as described in the first aspect.

[0021] In a third aspect, the present invention provides a battery, comprising the battery top cover as described in the second aspect.

[0022] In a fourth aspect, the present invention further provides a method for sealing and helium testing a battery liquid injection hole, the method comprising the following steps:

[0023] Sequentially placing the sealing nail, the helium capsule and the sealing nail in the injection hole, and then performing sealing welding of the sealing nail;

[0024] After sealing and welding, the helium capsule is melted and helium inspection is carried out.

[0025] The sealing and helium inspection method provided by the present invention obtains the sealing component provided by the first aspect after sealing, and performs a helium inspection on the corresponding sealing component.

[0026] According to the sealing and helium detection method provided by the present invention, after the helium capsule is melted and broken, the helium is released. If the sealing effect of the sealing nail is poor, the leaked helium can be directly detected during the helium detection. In this way, even if the helium in the battery is blocked by the sealing nail, it will not affect the detection of the sealing effect of the sealing nail, and the accuracy of the detection is improved, and the difficulty of the helium detection is reduced, so that the safety performance of the battery can be effectively improved. The sealing and helium detection method is simple and easy to operate, and is suitable for large-scale production.

[0027] Meanwhile, the specific processes of helium detection in the present invention are all conventional technical means, that is, the specific helium detection processes disclosed and known to those skilled in the art are applicable to the present invention.

[0028] Preferably, the melting point of the helium capsule is 80-140°C, for example, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C or 140°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] In the present invention, if the melting temperature is too low, the sealing pins are easily damaged by heat in advance during welding, affecting subsequent inspections. If the melting temperature is too high, the operating temperature of the helium capsule is likely to affect the stability of the battery cell.

[0030] It should be noted that the method for inserting the sealing glue nail and the sealing welding method for the sealing nail provided by the present invention are both conventional technical means, which are known to those skilled in the art and can realize the sealing process in the present invention, and the present invention is applicable to both of them.

[0031] The material selection of the helium capsule provided by the present invention is not particularly limited. The present invention is applicable to any material within a suitable melting temperature range and which will not affect the sealing result and the helium detection result, including but not limited to gel materials or fiber materials.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The sealing assembly provided by the present invention has a containing space for accommodating detection gas between the sealing pin and the sealing glue pin. When the helium test is performed, the helium therein is released, and the welding effect of the sealing pin can be accurately known, thereby improving the accuracy of the helium test and further improving the safety performance of the battery.

[0034] (2) The sealing and helium detection method provided by the present invention releases helium after the helium capsule is melted. If the sealing effect of the sealing nail is poor, the leaked helium can be directly detected during the helium detection. In this way, even if the helium in the battery is blocked by the sealing nail, it will not affect the detection of the sealing effect of the sealing nail. The accuracy of the detection is improved and the difficulty of the helium detection is reduced, thereby effectively improving the safety performance of the battery. The sealing and helium detection method is simple and easy to operate, and is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic structural diagram of the sealing assembly provided in Example 1.

[0036] Figure 2 This is a schematic diagram of the structure of the sealing nail provided in Example 1.

[0037] Figure 3 This is a schematic diagram of the structure of the sealing assembly provided for Comparative Example 1.

[0038] Among them, 1-sealing nail, 2-sealing glue nail, 3-accommodating space, 4-helium capsule, 21-upper end surface, 22-concave cavity, 23-guide outer peripheral surface, A-liquid injection hole. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0040] Example 1

[0041] This embodiment provides a sealing assembly for a battery liquid injection hole, such as Figure 1 As shown, the sealing assembly includes a sealing nail 1 and a sealing glue nail 2, which are sequentially arranged in the injection passage along the injection direction of the electrolyte, and an accommodating space 3 for accommodating the detection gas is provided between the sealing nail 1 and the sealing glue nail 2.

[0042] like Figure 2 As shown, the sealing nail 2 includes an upper end surface 21 arranged opposite to the lower end surface of the sealing nail 1, and the upper end surface 21 of the sealing nail 2 and the lower end surface of the sealing nail 1 together form an accommodating space 3;

[0043] A concave cavity 22 is provided on the surface of the sealing glue nail 2 facing the sealing nail 1 , and the bottom surface of the concave cavity 22 constitutes an upper end surface 21 arranged opposite to the sealing nail 1 . The concave cavity 22 is used to place the helium capsule 4 .

[0044] The depth of the cavity 22 is 0.6 mm.

[0045] The sealing nail 2 comprises a guiding outer peripheral surface 23 with a continuously decreasing outer diameter along the electrolyte injection direction.

[0046] The sealing assembly is used to seal the battery filling hole A.

[0047] This embodiment also provides a method for sealing and helium testing a battery liquid injection hole. The specific sealing and helium testing method is as follows (sealing is performed using the sealing assembly provided above):

[0048] (1) Pressing the sealant nail into the helium injection position of the injection hole once, wherein the arc groove in the sealant nail is located at the helium injection position of the injection hole, and after the helium is injected, pressing the sealant nail into the preset position of the sealant nail in the injection hole for a second time;

[0049] (2) After the sealing nail is positioned at the preset position of the injection hole, a helium capsule is placed in the groove of the sealing nail (the polyvinylidene fluoride PVDF shell is filled with helium to form a helium capsule);

[0050] (3) After placing the helium capsule, the sealing pins are welded on the surface of the injection hole to complete the sealing of the battery injection hole;

[0051] (4) After the battery injection hole is completely sealed, the helium capsule is melted and ruptured at the sealing pin at a temperature of 100°C. After the helium capsule is melted and ruptured, a helium inspection is performed;

[0052] Example 2

[0053] The difference between this embodiment and embodiment 1 is that the depth of the groove 23 in this embodiment is 0.9 mm.

[0054] The remaining structures, parameters, sealing and helium detection methods are consistent with those in Example 1.

[0055] Example 3

[0056] The difference between this embodiment and embodiment 1 is that the depth of the groove 23 in this embodiment is 0.3 mm.

[0057] The remaining structures, parameters, sealing and helium detection methods are consistent with those in Example 1.

[0058] Example 4

[0059] The difference between this embodiment and embodiment 1 is that the depth of the groove 23 in this embodiment is 1 mm.

[0060] The remaining structures, parameters, sealing and helium detection methods are consistent with those in Example 1.

[0061] Example 5

[0062] The difference between this embodiment and embodiment 1 is that in this embodiment, the upper end surface 21 of the sealing nail is not provided with a cavity 22, and the helium capsule 4 is directly located on the flat end surface of the upper end surface 21 of the sealing nail 2 (that is, the upper end surface 21 of the sealing nail 2, the lower end surface of the sealing nail 1 and the inner wall of the injection passage together form an accommodating space 3).

[0063] The remaining structures, parameters, sealing and helium detection methods are consistent with those in Example 1.

[0064] Comparative Example 1

[0065] The difference between this comparative example and Example 1 is that Figure 3 As shown, Figure 3 As shown, Figure 3 A is the mark of the injection hole. Along the battery injection direction, the sealing assembly includes a sealing nail 1 and a sealing glue nail 2 in sequence. The sealing nail 1 is located on the outer surface of the battery injection hole A.

[0066] This comparative example also provides a sealing and helium detection method, the specific method is:

[0067] (1) Pressing the sealant nail into the helium injection position of the injection hole once, wherein the arc groove in the sealant nail is located at the helium injection position of the injection hole, and after the helium is injected, pressing the sealant nail into the preset position of the sealant nail in the injection hole for a second time;

[0068] (2) After the sealing nail is positioned at the preset position of the injection hole, the sealing nail is sealed and welded on the surface of the injection hole, and the battery injection hole is sealed;

[0069] (3) After the battery filling hole is completely sealed, helium inspection is performed; no test examples are available

[0070] The sealing assembly provided by the present invention has an accommodating space for accommodating the detection gas between the sealing nail and the sealing glue nail, so that the welding effect of the sealing nail can be accurately known, the accuracy of the helium detection is improved, and the safety performance of the battery is further improved.

[0071] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A sealing assembly, characterized in that, it includes a sealing nail and a sealing glue nail, the sealing nail and the sealing glue nail are sequentially arranged in the liquid injection passage along the injection direction of the electrolyte, and there is an accommodation space for accommodating the detection gas between the sealing nail and the sealing glue nail.

2. The sealing assembly according to claim 1, characterized in that, the sealing assembly further includes a capsule containing the detection gas, and the capsule is placed in the accommodation space.

3. The sealing assembly according to claim 1, characterized in that, the sealing glue nail includes an upper end face disposed opposite to the lower end face of the sealing nail, and the upper end face of the sealing glue nail and the lower end face of the sealing nail enclose the accommodation space; or, the upper end face of the sealing glue nail, the lower end face of the sealing nail and the inner wall of the liquid injection passage enclose the accommodation space.

4. The sealing assembly according to claim 3, characterized in that, a concave cavity is provided on the surface of the sealing glue nail facing the sealing nail, and the bottom surface of the concave cavity constitutes the upper end face disposed opposite to the sealing nail, and the concave cavity is used for placing the capsule storing the detection gas.

5. The sealing assembly according to claim 4, characterized in that, the depth of the concave cavity is 0.6 - 0.9 mm.

6. The sealing assembly according to claim 1, characterized in that, the sealing glue nail includes a guiding outer peripheral surface with a continuously decreasing outer diameter along the injection direction of the electrolyte.

7. A battery top cover, characterized in that, the battery top cover includes a liquid injection hole communicating the battery inner cavity and the outside; the liquid injection hole is provided with the sealing assembly according to any one of claims 1 - 6.

8. A battery, characterized in that, the battery includes the battery top cover according to claim 7.

9. A method for sealing and helium leak detection of a battery liquid injection hole, characterized in that, the sealing and helium leak detection method includes the following steps: sequentially place the sealing glue nail, the helium gas capsule and the sealing nail in the liquid injection hole, and then perform the sealed welding of the sealing nail; after the sealed welding, melt the helium gas capsule to perform helium leak detection.

10. According to the sealing and helium leak detection method of claim 9, characterized in that, the melting temperature of the helium gas capsule is 80 - 140 °C.

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