Sealing element, battery cover plate, battery and electric device

Abstract

The invention relates to the technical field of batteries, in particular to a sealing element, a battery cover plate, a battery and a power utilization device, the sealing element comprises a main body, the main body is provided with a convex part, and the main body comprises a helium absorption material; the rubber plug is located on the side, provided with the protruding part, of the main body, and the protruding part is embedded in the rubber plug. By adopting the sealing element, the backpressure helium leak detection rate can be greatly improved, the leak detection problem is solved, and the detection accuracy is improved.

Description

Technical Field

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

[0002] At present, commercial batteries all use electrolyte as electrolyte. During the preparation process, a liquid injection hole is reserved on the outer packaging for injecting electrolyte, and the liquid injection hole is usually sealed with a plastic flat nail. Then a sealing cover is placed on the liquid injection hole step above the plastic flat nail, and the sealing cover is welded to the battery cover plate by laser welding; after the sealing cover is welded to the liquid injection countersunk hole step, an external seal is formed for the plastic flat nail. The structural diagram is shown in FIG. Figure 1 When defects (such as holes) appear in the welding area, water vapor or oxygen in the air may corrode the rubber plug of the plastic flat nail, causing the electrolyte to overflow to the outside of the battery cell through the corroded rubber plug, thereby posing a safety risk to the battery cell or the package composed of the battery cells.

[0003] In order to detect whether there are welding defects in the sealing welding area, the back pressure helium detection method is currently used to test the sealing of the weld, but this method is prone to miss detection when there are large holes in the sealing welding area. Therefore, the current relevant technology still needs to be improved. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, the present invention provides a seal, a battery cover, a battery and an electrical device that can effectively improve the accuracy of back pressure helium detection.

[0005] In the first aspect of the present application, a seal is provided. According to an embodiment of the present application, the seal comprises: a main body, the main body having a raised portion, the main body comprising a helium-absorbing material; a rubber plug, the rubber plug being located on a side of the main body provided with the raised portion, the raised portion being embedded in the rubber plug. As a result, the helium-absorbing material in the main body has a strong helium adsorption capacity, and when the weld has large or extra-large holes, the leakage rate of the back pressure helium detection can be increased, thereby improving the problem of missed detection and effectively improving the accuracy of the back pressure helium detection.

[0006] According to an embodiment of the present application, the main body includes a matrix and the helium absorbing material, the helium absorbing material is dispersed in the matrix, and the helium adsorption capacity of the helium absorbing material is greater than the helium adsorption capacity of the matrix; or the main body is composed of the helium absorbing material.

[0007] According to an embodiment of the present application, the main body includes a cap and the protrusion connected to the cap, and the helium absorbing material is at least located in the cap.

[0008] According to an embodiment of the present application, the mass ratio of the substrate to the helium absorbing material is 1:5-10.

[0009] According to an embodiment of the present application, the matrix includes at least one of polyphenylene sulfide, polyethylene terephthalate, acrylonitrile-butadiene-styrene, polycarbonate, polyamide, polybutylene terephthalate, polyoxymethylene, and polyphenylene ether.

[0010] According to an embodiment of the present application, the helium absorbing material includes at least one of activated carbon powder, aluminum oxide powder, silicon oxide powder, and silica gel.

[0011] According to an embodiment of the present application, the D50 particle size of the helium absorbing material is 5.0 μm to 15 μm.

[0012] According to an embodiment of the present application, the specific surface area of ​​the helium absorbing material is 200m 2 / g~1300m 2 / g.

[0013] In a second aspect of the present application, a battery cover is provided. According to an embodiment of the present application, the battery cover comprises: a cover body, the cover body is provided with a liquid injection hole; the aforementioned sealing member, the sealing member is interference fit in the liquid injection hole. It can be understood that with the aforementioned sealing member, the missed detection rate of the back pressure helium inspection of the battery cover is low.

[0014] In a third aspect of the present application, a battery is provided. According to an embodiment of the present application, the battery includes the battery cover plate described above. The battery has all the features and advantages of the battery cover plate described above, which will not be described one by one here.

[0015] In a fourth aspect of the present application, an electric device is provided. According to an embodiment of the present application, the electric device includes the battery described above. The electric device has all the features and advantages of the battery described above, which will not be described one by one here. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of sealing the liquid injection hole of the battery cover with a sealing nail.

[0017] Figure 2 This is a schematic diagram of the principle of back pressure helium detection.

[0018] Figure 3 It is a schematic structural diagram of a seal according to an embodiment of the present application.

[0019] Figure 4 It is a schematic structural diagram of a battery cover according to an embodiment of the present application.

[0020] Reference numerals:

[0021] 11: Sealing cover 12: Sealing nail 121: Raised part 13: Battery cover 14: Liquid injection hole 15: Weld 16: Sealed space 21: Sealing cover 22: Sealing nail 23: Battery cover 25: Weld 26: Sealed space 27: Sealing head 28: Sealing ring 29: Sealed space 2 201, 203: Mechanical pump 202: Helium pressure unit 204: Vacuum gauge 205: Detection unit A, B, C, D: Vacuum valve 31: Main body 311: Raised part 32: Rubber plug 312: Cap 40: Cover body 41: Liquid injection hole 42: Seal 421: Rubber plug 43: Sealing cover DETAILED DESCRIPTION

[0022] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0023] This application is made based on the following discoveries and understandings of the inventors:

[0024] In the commonly used batteries, the welding of the welding sealing area of ​​the sealing cover above the sealing nail is directly related to the risk of leakage. Therefore, it is necessary to inspect whether there are defects in the welding sealing area during the production process. At present, in order to detect whether the weld has welding defects, the back pressure helium inspection method is used to inspect the sealing of the weld. The detection principle is: if there is a defect (leak) in the weld, first press helium into the sealed space 1 at a certain pressure at the helium compression station, and then detect the helium in the sealed space 26 at the helium inspection station. The leakage rate (leak rate) leaking from the welding leak is used to determine the quality of the sealing welding. The specific process is as follows: Figure 2As shown, the battery is first moved to the helium compression station, and after the sealing ring on the sealing head covers (avoiding the weld) the sealing cover on the injection hole, the vacuum valve A is opened, the vacuum valve B is closed, and the mechanical pump 201 evacuates the sealed space 29. After reaching the set pressure, the vacuum valve A is closed, the vacuum valve B is opened, and a certain amount of helium is injected into the sealed space 29 through the helium compression unit; if there are holes in the sealing weld at this time, the helium in the sealed space 29 enters the sealed space 26 through pressure, and if there are no holes in the weld, no helium enters the sealed space 26; after the helium compression is completed, the battery is transferred to the helium inspection station, and the vacuum Valve C is opened first, and the mechanical pump 203 first evacuates the sealed space 29 and the sealed space 26 (assuming that there are holes on the weld). When a certain vacuum degree is reached, the vacuum valve C is closed, and the vacuum valve D (detection valve) is opened. The helium in the sealed space 26 escapes into the sealed space 29 and is detected by the detection unit (such as a mass spectrometer) 205 through the detection valve D, and its leakage rate is calculated. The leakage rate is compared with the standard leakage rate (also called the upper limit of the qualified weld leakage rate standard, which can be taken as 3.0E-6mbar·L / S). If the helium leakage rate is less than the standard leakage rate, it is judged that the sealing welding is qualified (OK). If the helium leakage rate is greater than or equal to the standard leakage rate, it is judged that the sealing welding is unqualified (NG).

[0025] In the actual helium inspection process, as the holes in the weld grow from small to large, the back pressure helium leak detection first increases to a maximum peak value, and then gradually decreases. When the holes in the weld are large or extra large, the back pressure helium leak detection rate is less than the standard leak rate. At this time, missed detection will occur.

[0026] In order to solve the above problems to a certain extent, the inventors of the present application have discovered through research that adding materials with strong helium absorption ability to the sealing nails can improve the helium leak detection rate when there are large or extra-large holes in the weld, improve the problem of missed detection, and improve the accuracy of back pressure helium detection.

[0027] In view of this, in the first aspect of the present application, a sealing member is provided. According to an embodiment of the present application, referring to Figure 3 The seal comprises: a main body 31, the main body 31 has a protrusion 311, the main body 31 includes a helium absorbing material; a rubber plug 32, the rubber plug 32 is located on one side of the main body 31 provided with the protrusion 311, and the protrusion 311 is embedded in the rubber plug 32. Therefore, the helium absorbing material in the main body has a strong helium adsorption capacity, and when the weld has a large or super-large hole, the leakage rate of the back pressure helium detection can be increased, thereby improving the problem of missed detection and effectively improving the accuracy of the back pressure helium detection.

[0028] It can be understood that there is no particular limitation on the specific arrangement of the helium absorbing material in the main body. For example, the helium absorbing material may be arranged only in a part of the main body, or in the entire main body, or the entire main body may be made of the helium absorbing material.

[0029] In some embodiments, the main body includes a matrix and the helium absorbing material, the helium absorbing material is dispersed in the matrix, and the helium absorbing material has a greater helium absorbing capacity than the matrix. Thus, the accuracy of back pressure helium detection can be effectively improved when the weld has large holes or super large holes.

[0030] In some embodiments, reference Figure 3 The main body 31 includes a cap 312 and a raised portion 311 connected to the cap 312, and the helium absorbing material is at least located in the cap 312. Specifically, the raised portion is embedded in the rubber plug 32 and cannot come into contact with helium during back pressure helium detection. Therefore, the helium absorbing material can be arranged only in the cap, which also has a good effect of improving the back pressure helium leak detection rate.

[0031] In some embodiments, the mass ratio of the matrix to the helium absorbing material is 1:5 to 10, such as 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, etc. Specifically, when the amount of helium absorbing material is small, the raw material of the matrix accounts for too much, the helium storage capacity of the main body is not good, and there may still be a possibility of missed detection; when the amount of helium absorbing material is too much, the proportion of helium absorbing material is too large, which may cause the main body to be unformed or have low mechanical strength during the preparation process, and fail to meet the performance requirements of the seal. When the matrix and the helium absorbing material are within the above-mentioned ratio range, both the improvement of the helium absorbing capacity and the strength requirements of the seal can be taken into account, and it has better performance.

[0032] In some embodiments, the matrix may include at least one of polyphenylene sulfide, polyethylene terephthalate, acrylonitrile-butadiene-styrene, polycarbonate, polyamide, polybutylene terephthalate, polyoxymethylene, and polyphenylene oxide. Thus, the seal has better performance, is easy to process, has a wide range of material sources, and has low cost.

[0033] In some embodiments, the helium absorbing material may include at least one of activated carbon powder, aluminum oxide powder, and silicon oxide powder, thereby having better helium absorbing performance, better compatibility with the substrate, and a wide range of material sources and low cost.

[0034] In some embodiments, the D50 particle size of the helium absorbing material is 5.0 μm to 15 μm, such as 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, etc.

[0035] In some embodiments, the specific surface area of ​​the helium absorbing material is 200m 2 / g~1300m 2 / g, such as 200m 2 / g、300m 2 / g, 400m 2 / g、500m 2 / g、600m 2 / g、700m 2 / g、800m 2 / g、900m 2 / g、1000m 2 / g、1100m 2 / g、1200m 2 / g、1300m 2 / g, etc.

[0036] Specifically, within the above-mentioned particle size range, the adsorbent material has a suitable specific surface area, a large contact area with helium, a strong helium absorption capacity, better compatibility with the substrate, easy injection molding preparation, and the mechanical strength of the obtained seal is suitable. If the particle size of the helium absorbing material is too large, the specific surface area of ​​the helium absorbing material is relatively small, the ability to absorb helium and the compatibility with the substrate may be relatively reduced, the difficulty of preparation may increase, and the mechanical strength of the main body and the ability to absorb helium may also decrease; if the particle size of the helium absorbing material is too small, the specific surface area of ​​the helium absorbing material increases, and the ability to absorb helium increases, but there is a risk of being wrapped by the substrate during the preparation process, and the ability to absorb helium of the final product decreases.

[0037] In some embodiments, the main body is made of the helium absorbing material, thereby improving the accuracy of back pressure helium detection.

[0038] In some embodiments, the helium absorbing material may be silica gel, thereby having better helium absorbing performance and being more conducive to improving the accuracy of back pressure helium detection.

[0039] It can be understood that the sealing member of the embodiment of the present application is used to seal the injection hole in the battery cover, and its specific shape can be set according to the shape of the injection hole. In some embodiments, the sealing member can include but is not limited to sealing nails.

[0040] In a second aspect of the present application, a battery cover is provided. According to an embodiment of the present application, referring to Figure 4 The battery cover comprises: a cover body 40, on which a liquid injection hole 41 is arranged; and the aforementioned sealing member 42, which is interference-fitted in the liquid injection hole 41. It can be understood that with the aforementioned sealing member, the missed detection rate of the back pressure helium detection of the battery cover is low.

[0041] In a third aspect of the present application, a battery is provided. According to an embodiment of the present application, the battery includes the battery cover plate described above. The battery has all the features and advantages of the battery cover plate described above, which will not be described one by one here.

[0042] It can be understood that there is no other limitation on the specific type of the battery, including but not limited to lithium-ion batteries, sodium-ion batteries, etc., and the battery can be a square shell battery, a soft pack battery, a cylindrical battery, etc., and can be in different forms such as a battery cell, a battery module, a battery pack, etc.

[0043] It can also be understood that the battery may include other necessary structures and components of conventional batteries. Taking a lithium-ion battery as an example, it may include an outer package, and an electrode assembly and an electrolyte contained in the outer package, and the electrode assembly may include a positive electrode sheet, a negative electrode sheet, and a separator located between the positive electrode sheet and the negative electrode sheet.

[0044] As an example, the positive electrode sheet may include a positive electrode current collector and a positive electrode film layer located on at least one side of the positive electrode current collector, and the positive electrode film layer generally contains a positive electrode active material, a conductive agent and a binder. The negative electrode sheet may include a negative electrode current collector and a negative electrode film layer located on at least one side of the negative electrode current collector, and the negative electrode film layer generally contains a negative electrode active material, a conductive agent and a binder. The separator may be a polymer separator of a single-layer structure or a multi-layer structure (including but not limited to a polyethylene separator, a polypropylene separator, a polyethylene polypropylene composite separator, etc.). The electrolyte generally may include an electrolyte salt and a solvent. The above-mentioned positive electrode active material, binder, conductive agent, current collector, electrolyte salt and solvent can be selected with reference to conventional technology, and this application does not make any special restrictions.

[0045] In a fourth aspect of the present application, an electric device is provided. According to an embodiment of the present application, the electric device includes the battery described above. The electric device has all the features and advantages of the battery described above, which will not be described one by one here.

[0046] According to an embodiment of the present application, the power-consuming device may include a mobile device (such as a mobile phone, a laptop computer, etc.), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship and a satellite, an energy storage system, etc., but is not limited thereto. The battery may be used as a power source for the power-consuming device, or may be used as an energy storage unit for the power-consuming device.

[0047] It can be understood that in addition to the battery mentioned above, the electrical device can also include the necessary structures and components of conventional electrical devices. Taking electric vehicles as an example, they can include the necessary structures and components such as the body, windows, chassis, engine, seats, tires, etc., which will not be repeated here.

[0048] The embodiments of the present application are described in detail below.

[0049] The following examples and comparative examples are all prepared according to the following method. The different parameters are shown in Table 1 below:

[0050] The matrix is ​​made of PPS (polyphenylene sulfide) material or PET (polyethylene terephthalate), and the helium absorbing material is activated carbon powder or alumina powder. The D50 particle size of the activated carbon powder is 10.0±1.0μm, and the specific surface area is 1100m 2 / g; the D50 particle size of alumina powder is 8.0±1.0μm, and the specific surface area is 260m 2 / g~300m 2 / g; 10 sealing nails were made in each embodiment.

[0051] The specific preparation process is: the base material and the helium absorbing material are mixed in a certain proportion to form a mixed material, and then injection molding is performed to form a plastic head of the sealing nail (i.e., the main body of the seal), wherein the injection molding pressure is 120 bar to 200 bar, and the injection molding temperature is 250° C. to 400° C.

[0052] Performance Test:

[0053] 1. Appearance of seal: If the surface of the plastic head is smooth, without burrs or powder falling after injection molding, the appearance is good and recorded as OK; if the surface of the plastic head is pitted, or has burrs, or powder falling, the appearance is poor and recorded as NG.

[0054] 2. Back pressure helium test: Put the prepared plastic head cover on the rubber plug and plug it into the injection hole of the battery. Do not weld the sealing cover (equivalent to the weld having the largest hole). Directly use the back pressure helium test method to detect its leakage rate. The test leakage rate value of each sealing nail is the average value of 10 samples.

[0055] The helium detection judgment method is that if the helium leak rate is ≤3.0E-06, it means the welding is good, and it is recorded as OK; otherwise, it means the welding is bad, and it is recorded as NG.

[0056] The performance test results are shown in Table 1 below.

[0057] Table 1

[0058] Example Weight ratio of matrix and helium absorbing material Helium leak detection rate Plastic head appearance Helium detection Remark Example 1 PPS: activated carbon powder = 1:5 6.52E-06 OK NG Example 2 PPS: activated carbon powder = 1:7 4.47E-05 OK NG Example 3 PPS: activated carbon powder = 1:10 9.36E-05 OK NG Example 4 PET: activated carbon powder = 1:5 5.43E-06 OK NG Example 5 PET: activated carbon powder = 1:7 4.80E-05 OK NG Example 6 PET: activated carbon powder = 1:10 8.60E-05 OK NG Example 7 PPS: Alumina powder = 1:7 4.80E-05 OK NG Example 8 PET: Alumina powder = 1:7 4.36E-05 OK NG Comparative Example 1 PPS(All) 1.53E-06 OK OK Missed Comparative Example 2 PET(All) 2.23E-06 OK OK Missed

[0059] According to the above test results, by adding helium absorbing materials into the matrix, the leakage rate of back pressure helium detection can be effectively improved and the problem of missed detection can be improved.

[0060] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0061] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0062] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A sealing member, characterized in that: include: A main body, the main body having a protrusion, and the main body comprising a helium absorbing material; The rubber plug is located at a side of the main body where the raised portion is provided, and the raised portion is embedded in the rubber plug.

2. The seal according to claim 1, characterized in that The main body comprises a matrix and the helium absorbing material, the helium absorbing material is dispersed in the matrix, and the helium absorbing capacity of the helium absorbing material is greater than the helium absorbing capacity of the matrix; or The body is composed of the helium absorbing material.

3. The seal according to claim 2, characterized in that The main body comprises a cap and the protruding portion connected to the cap, and the helium absorbing material is at least located in the cap.

4. The seal according to claim 2, characterized in that The mass ratio of the substrate to the helium absorbing material is 1:5-10.

5. The seal according to claim 2, characterized in that The matrix includes at least one of polyphenylene sulfide, polyethylene terephthalate, acrylonitrile-butadiene-styrene, polycarbonate, polyamide, polybutylene terephthalate, polyoxymethylene, and polyphenylene ether.

6. The seal according to claim 1 or 2, characterized in that: The helium absorbing material includes at least one of activated carbon powder, aluminum oxide powder, silicon oxide powder and silica gel.

7. The seal according to claim 1 or 2, characterized in that: The D50 particle size of the helium absorbing material is 5.0 μm to 15 μm.

8. The seal according to claim 1 or 2, characterized in that: The specific surface area of ​​the helium absorbing material is 200m 2 / g~1300m 2 / g.

9. A battery cover, characterized in that: include: A cover plate body, wherein the cover plate body is provided with a liquid injection hole; The sealing member according to any one of claims 1 to 8 is arranged in the injection hole by interference fit.

10. A battery, characterized in that: Including the battery cover plate as claimed in claim 9.

11. An electrical device, characterized in that: Comprising the battery as claimed in claim 10.

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