WO2021057763A1 - 锂电池及锂电池的气密检测方法 - Google Patents

锂电池及锂电池的气密检测方法 Download PDF

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Publication number
WO2021057763A1
WO2021057763A1 PCT/CN2020/116997 CN2020116997W WO2021057763A1 WO 2021057763 A1 WO2021057763 A1 WO 2021057763A1 CN 2020116997 W CN2020116997 W CN 2020116997W WO 2021057763 A1 WO2021057763 A1 WO 2021057763A1
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Prior art keywords
air bag
gas
lithium battery
liquid injection
sealing plug
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PCT/CN2020/116997
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English (en)
French (fr)
Inventor
胡忠汉
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湖南弘毅科技有限公司
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Publication date
Priority claimed from CN201910900736.7A external-priority patent/CN112542664A/zh
Priority claimed from CN201921584346.5U external-priority patent/CN210837928U/zh
Priority claimed from CN202020168208.5U external-priority patent/CN211743333U/zh
Application filed by 湖南弘毅科技有限公司 filed Critical 湖南弘毅科技有限公司
Publication of WO2021057763A1 publication Critical patent/WO2021057763A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/60—Arrangements or processes for filling or topping-up with liquids; Arrangements or processes for draining liquids from casings
    • H01M50/609—Arrangements or processes for filling with liquid, e.g. electrolytes
    • H01M50/627—Filling ports
    • H01M50/636—Closing or sealing filling ports, e.g. using lids
    • H01M50/645—Plugs

Definitions

  • the invention relates to the technical field of battery tightness detection, in particular to a lithium battery and a method for detecting airtightness of the lithium battery.
  • Lithium batteries have attracted much attention due to their many advantages such as high energy density, high output power, long charge and discharge life, fast charging, green and pollution-free, wide operating temperature range and small self-discharge.
  • the internal chemical system of lithium batteries is very active, and it is very easy to cause side reactions with external moisture and air to cause battery performance degradation or failure. Therefore, the air tightness of the package is very important to the reliability and safety of lithium batteries. How to effectively detect the air-tightness of lithium batteries and ensure that poorly packaged products will not flow into the consumer market is of great significance.
  • lithium batteries use a rubber plug to close the liquid injection port after liquid injection to ensure a certain degree of vacuum inside the battery, and then laser weld a sealed aluminum sheet above the liquid injection port for sealing. Because of the sealing properties of the rubber plug, the detection gas pre-injected into the battery cannot enter the space between the rubber plug and the sealed aluminum sheet, so that the welding airtightness of the sealed aluminum sheet cannot be detected.
  • a lithium battery includes a battery body.
  • the battery body is provided with a liquid injection hole and a liquid injection port communicating with the liquid injection hole; a sealing plug that is sealed and matched with the liquid injection hole;
  • the liquid injection port is welded and sealed; an air bag, the air bag is arranged between the sealing plug and the repair welding piece, and the inside of the air bag contains the gas to be inspected; wherein, when the repair welding piece is welded and sealed When the liquid injection port is used, the gas bag can be melted so that the tested gas is released between the sealing plug and the repair welding piece.
  • a groove is provided on the top of the sealing plug, and the air bag is placed in the groove.
  • the top of the sealing plug is provided with a cross-shaped groove or a straight groove for the sealing plug to be screwed into the liquid injection hole; the groove is at least partially disposed in the cross-shaped groove. Groove or in-line groove.
  • the air bag is at least partially protruded from the sealing plug.
  • the sealing plug is an elastic sealing plug or the air bag is an elastic air bag; the air bag is at least partially protruding from the liquid injection port.
  • the sealing plug includes a cylindrical body and a cone head, and the cone head is disposed at one end of the cylindrical body.
  • the detected gas is at least one selected from nitrogen, hydrogen, and inert gas; the inert gas is helium, neon, argon, krypton, xenon, or radon.
  • the shape of the air bag is spherical, elliptical or square.
  • the material of the air bag is selected from at least one of PP, PE, PET and PVC.
  • a method for detecting airtightness of a lithium battery includes: providing a battery body with a liquid injection hole and a liquid injection port communicating with the liquid injection hole; and sealing a sealing plug with the liquid injection hole Fit; place the gas bag on the sealing plug, the inside of the gas bag contains the gas to be inspected; weld the repair welding piece to the liquid injection port to be sealed with the liquid injection port, wherein the welding The heat generated when repairing the soldering piece melts the air bag, so that the tested gas is released between the repairing soldering piece and the sealing plug; detecting whether the lithium battery has the tested gas Escape.
  • the electrolyte is injected into the liquid injection port
  • a sealing plug is inserted into the liquid injection hole, and the air bag is placed before welding the repair welding piece to the liquid injection port.
  • the sealing plug weld and seal the repair welding piece corresponding to the liquid injection port.
  • the welding generates a large amount of heat, which heats the air bag, and then melts and releases the gas to be inspected between the sealing plug and the welding patch.
  • the airtightness test of the lithium battery is carried out through the airtightness detection equipment to detect whether there is a leak of the detected gas, and then it can be judged whether the repair welding piece is well sealed.
  • a lithium battery includes a battery cell, a shell, a first pole cap, a first pole ear, and an air bag.
  • the first pole cap is placed on the first pole of the cell, and the edge of the first pole cap is connected to the The edge of the shell is connected to and wraps the battery, the first tab is placed in the cavity between the first pole of the battery and the first pole cap, and the air bag is disposed on the In the cavity between the first pole of the battery cell and the first pole cap, the gas bag contains the gas to be tested, wherein the first pole cap moves vertically downwards toward the first pole ear The air bag is squeezed from time to time, so that the tested gas is released in the cavity.
  • the first tab has a C-shaped structure, and the first end of the first tab is connected to the bottom of the first tab, and the second tab of the first tab is The terminal is connected with the first terminal of the battery cell.
  • the air bag is at least partially interposed between the first end and the second end of the first tab.
  • the top middle part of the first pole cap protrudes outwardly to form a first pole cap as a whole.
  • a sharp corner protruding downward is provided on the bottom side of the first pole cap, and the sharp corner is pressed against the top of the first end.
  • This arrangement can increase the vertical pressure of the bottom side of the first pole cap on the first end surface of the first pole ear, so as to improve the efficiency of crushing the air bag.
  • the first tab is an elastic metal sheet.
  • the first pole cap is connected and sealed with the edge of the housing. In this way, the sealing action of the first-pole cap and the casing during the battery packaging process can be used to crush the gas bag containing the gas to be tested, which can be used for subsequent detection of whether there is a leak of the gas to be tested to further determine the battery's tightness.
  • the detected gas is selected from at least one of nitrogen, hydrogen, and inert gas.
  • the air bag is spherical, oval or square.
  • the diameter of the gas bag after being filled with the gas to be tested is greater than the vertical distance from the first end of the first tab to the first end of the battery cell after the lithium battery is sealed; or the gas to be tested It is helium gas and the diameter of the air bag is smaller than the vertical distance from the first end of the first tab to the first end of the battery after sealing. This can ensure that during the sealing process, the gas bag is crushed by the first end of the first tab to release the test gas; or helium molecules penetrate the low-density gas bag and escape into the cavity.
  • the cavity between the first pole of the lithium battery and the cap of the first pole contains the gas to be tested, and then put the sealed battery on a dedicated gas detection instrument for testing to detect whether the gas to be tested overflows. Determine whether the battery is completely sealed.
  • the function of injecting the tested gas into the cavity between the first pole and the cap of the first pole is realized, and the operation is very simple, and there is no need to modify the existing battery packaging production line, and it also eliminates the need for the prior art.
  • the necessary equipment is injected into the gas to be detected, and the production cost is low, and the battery can be directly placed in a special detector for the gas to be detected in the prior art.
  • the above-mentioned lithium battery is achieved by placing an air bag containing the gas to be tested under the first electrode cap before sealing, and crushing the air bag by the pressure caused by the vertical movement of the first electrode cap and the shell sealing process. Release the detected gas into the packaged battery.
  • the air bag occupies a small space, does not need to change the structure of the lithium battery, and the operation process is simple, the subsequent detection is reliable, and the convenience and safety of the sealing detection of the lithium battery are improved.
  • FIG. 1 is a schematic diagram of the structure of a lithium battery in an embodiment.
  • FIG. 2 is a schematic diagram of the structure of the lithium battery shown in FIG. 1 from another perspective.
  • FIG. 3 is a schematic diagram of a partial enlarged structure of a part A of the lithium battery shown in FIG. 2.
  • Fig. 4 is a schematic structural diagram of a sealing plug of a lithium battery in an embodiment.
  • FIG. 5 is a schematic diagram of the packaging process of a lithium battery in an embodiment.
  • FIG. 6 is a schematic diagram of the packaging process of a lithium battery in an embodiment.
  • FIG. 7 is a schematic diagram of the completion of the packaging of the lithium battery in an embodiment.
  • the existing air tightness detection method of lithium batteries is to inject helium gas after the battery is filled with liquid, plug a rubber plug at the liquid injection port, and then put the air tightness detection device into the air tightness detection device.
  • the lithium battery 100 in an embodiment includes a battery body 10, a sealing plug 20 (see FIG. 3), a solder patch 30, and an air bag 40 (see FIG. 3).
  • the battery body 10 is provided with a liquid injection hole 11 and a liquid injection port 12 communicating with the liquid injection hole.
  • the sealing plug 20 is tightly matched with the liquid injection hole 11.
  • the repair welding piece 30 and the liquid injection port 12 are welded and sealed.
  • the inside of the gas bag 40 contains the gas to be detected.
  • the air bag 40 is arranged between the sealing plug 20 and the repair welding piece 30. When the repair welding piece 30 is welded and sealed to the liquid injection port 12, under the action of heat, the gas bag 40 can be melted so that the gas to be inspected is released between the sealing plug 20 and the repair welding piece 30.
  • the above-mentioned lithium battery 100 can detect whether the repair welding piece 30 has completed the sealing of the liquid injection port 12, and the detection method and operation are simple, so the reliability and safety of the lithium battery 100 can be ensured.
  • the air bag 40 occupies a small space, there is no need to change the structure of the existing lithium battery, so the cost of using this solution can be effectively reduced.
  • the battery body 10 includes a casing 13 and a cover plate 14 covering one side of the casing 13.
  • the casing 13 has a wound or laminated diaphragm material inside.
  • the cover plate 14 is provided with a positive electrode 141, a negative electrode 142 and a safety component 143.
  • the liquid injection hole 11 penetrates the cover plate 14, and the liquid injection port 12 is located on the outer surface of the cover plate 14.
  • the repair welding piece 30 covers the liquid injection port 12.
  • the liquid injection hole 11 is a counterbore
  • the sealing plug 20 is at least partially located at the step of the counterbore.
  • the top of the sealing plug 20 is provided with a groove, and the air bag 40 is placed in the groove. Due to the small size of the gap between the top of the sealing plug 20 and the repair welding piece 30, the groove can provide a certain space for accommodating the air bag 40, thereby increasing the volume of the gas to be tested in the air bag 40, and thereby melting the air bag 40. Breaking releases the inspected gas required for equipment inspection, thus improving the accuracy of air tightness inspection.
  • the shape of the groove may be hemispherical or other shapes that match the shape of the air bag 40, which is not limited herein.
  • the top of the sealing plug 20 is provided with a cross-shaped groove or a straight groove for the sealing plug 20 to be screwed into the liquid injection hole 11, and the groove is at least partially disposed in the cross-shaped groove or the straight groove.
  • a cross-shaped groove or a straight-shaped groove is provided on the top of the sealing plug 20, which facilitates the sealing plug 20 to be operated in a limited space to seal and cooperate with the liquid injection hole 11.
  • the groove is at least partially arranged in the cross-shaped groove or the in-line groove, which saves space while not obstructing the screwing of the sealing plug 20. It should be understood that a screwdriver can be used to fit the cross-shaped groove or the in-line groove on the top of the sealing plug 20 so that the sealing plug 20 is screwed into the liquid injection hole 11 to be sealed and matched.
  • the groove can be arranged at the center of the cross-shaped groove or the in-line groove.
  • the sealing plug 20 includes a cylindrical body 22 and a cone 23, and the cone 23 is disposed at one end of the cylindrical body 22.
  • the taper 23 can facilitate the sealing plug 20 to enter the liquid injection hole 11 to complete the sealing fit.
  • the cylindrical body 22 has a simple shape and can provide more space for the placement of the air bag 40, for example, when the liquid injection hole 11 is a counterbore ,
  • the sealing plug 20 can completely enter the through hole part of the counterbore, and is not arranged at the counterbore.
  • the sealing plug 20 may also be nail-shaped, which is not limited herein.
  • the air bag 40 is at least partially protruded from the sealing plug 20. In this way, the volume of the air bag 40 can be increased, thereby increasing the volume of the detected gas in the air bag 40, thereby increasing the amount of detected gas released by the air bag 40 by fusing and improving the accuracy of air tightness detection.
  • the sealing plug 20 is an elastic sealing plug.
  • the air bag 40 is an elastic air bag.
  • the air bag 40 is at least partially protruded from the liquid injection port 12. Before welding the repair welding piece 30 to the liquid injection port 12, the repair welding piece 30 should be fixed to the welding position corresponding to the liquid injection port 12 first. If the air bag 40 is at least partially protruding from the liquid injection port 12, and the sealing plug 20 is provided as an elastic sealing plug or the air bag 40 is an elastic air bag, the air bag 40 can be elastically deformed or the air bag 40 is compressed when the air bag 40 is compressed. Prompt the elastic sealing plug 20 to elastically deform, so as not to affect the fixation of the repair welding piece 20 at the welding position corresponding to the liquid injection port 12. Therefore, the volume of the gas bag 40 can be further increased, thereby increasing the amount of gas to be tested in the gas bag 40 Capacity to improve the accuracy of air tightness detection.
  • the shape of the air bag 40 is spherical, oval or square. In this embodiment, the shape of the air bag 40 is an ellipse.
  • the material of the air bag 40 is one or more of PP (polypropylene), PE (polyethylene), PET (polyethylene terephthalate), or PVC (polyvinyl chloride) combination.
  • the material of the air bag 40 is PP. It should be understood that the material of the air bag 40 should not have any chemical reaction with the material in the battery body 10 (for example, electrolyte).
  • the detected gas is one or more combinations of nitrogen, hydrogen, or inert gas, and the inert gas is helium, neon, argon, krypton, xenon, or radon.
  • the gas to be detected is helium.
  • an airtightness detection method of a lithium battery which includes the following steps:
  • a battery body 10 is provided.
  • the battery body 10 is provided with a liquid injection hole 11 and a liquid injection port 12 communicating with the liquid injection hole 11.
  • the liquid injection hole 11 can penetrate through the cover plate 14 of the battery body 10, and the liquid injection port 12 is located on the outer surface of the cover plate 14.
  • the sealing plug 20 can be an elastic sealing plug.
  • the top of the sealing plug 20 is provided with a cross-shaped groove or a straight groove for the sealing plug 20 to be screwed into the injection hole 11, and a screwdriver and the cross-shaped groove on the top of the sealing plug 20 can be used Or the in-line groove is matched, so that the sealing plug 20 is screwed into the liquid injection hole 11 to be sealed and matched.
  • the sealing plug 20 includes a cylindrical body 22 and a cone head 23, and the cone head 23 is disposed at one end of the cylindrical body 22.
  • the taper 23 can facilitate the sealing plug 20 to enter the liquid injection hole 11 to complete the sealing cooperation.
  • the sealing plug 20 may also be nail-shaped, which is not limited herein.
  • the shape of the air bag 40 is spherical, elliptical or square. In this embodiment, the shape of the air bag 40 is an ellipse.
  • the material of the air bag 40 is one or more combinations of PP (polypropylene), PE (polyethylene), PET (polyethylene terephthalate), or PVC (polyvinyl chloride). In this embodiment, the material of the air bag 40 is PP.
  • the detected gas is one or more combinations of nitrogen, hydrogen, or inert gas, and the inert gas is helium, neon, argon, krypton, xenon, or radon.
  • the gas to be detected is helium.
  • the top of the sealing plug 20 is provided with a groove, and the air bag 40 is placed in the groove. Further, the groove is at least partially disposed in the cross-shaped groove or the in-line groove.
  • the air bag 40 is at least partially protruding from the sealing plug 20, and further, the sealing plug 20 is an elastic sealing plug or the air bag 40 is an elastic air bag, and the air bag 40 is at least partially protruding from the liquid injection port 12.
  • the gas detection device can be used to detect whether the detected gas has escaped from the lithium battery 100.
  • the gas detection device may be a vacuum box leak detection device, including a vacuum box with a vacuum chamber, a vacuuming device, and a leak detector.
  • the lithium battery 100 after step S140 is placed in the vacuum chamber of the vacuum box, and then the vacuum chamber is evacuated by the vacuuming device. At this time, check whether the leak detector has leaked gas.
  • the lithium battery 100 and the method for detecting airtightness of the lithium battery of this embodiment have the following advantages:
  • the air bag 40 is placed in the groove, which can compensate for the small gap between the top of the sealing plug 20 and the repair welding piece 30, and provide a certain space for accommodating the air bag 40 , Thereby increasing the capacity of the gas to be detected in the air bag 40, thereby improving the accuracy of the air tightness detection;
  • the top of the sealing plug 20 is provided with a cross-shaped groove or a line-shaped groove for the sealing plug 20 to be screwed into the liquid injection hole 11, and the groove is at least partially set in the cross-shaped groove or the line-shaped groove, While not obstructing the screwing of the sealing plug 20, it also saves space;
  • the sealing plug 20 including a cylindrical body 22 and a cone head 23, when the liquid injection hole 11 is a counterbore, the sealing plug 20 can completely enter the through hole part of the counterbore instead of being arranged at the counterbore, Therefore, more space can be provided for the placement of the air bag 40;
  • the sealing plug 20 As an elastic sealing plug or the air bag 40 as an elastic airbag, the air bag 40 is at least partially protruding from the liquid injection port 12, so as not to affect the welding position of the repair welding piece 20 at the liquid injection port 12
  • the fixing of the air bag 40 can further increase the volume of the air bag 40 and improve the accuracy of air tightness detection.
  • the lithium battery in an embodiment includes a battery cell 1, a housing 3, a first pole cap 2, a first tab 4 and an air bag 5.
  • the first pole cap 2 is placed at the first end of the cell 1, and the edge of the first pole cap 2 is connected to the edge of the housing 3 and wraps the cell 1.
  • the first tab 4 is placed in the cavity 7 between the first pole end of the battery cell 1 and the first pole cap 2.
  • the air bag 5 is arranged in the cavity 7 between the first pole end of the battery cell 1 and the first pole cap 2.
  • the gas bag 5 contains the gas to be detected.
  • the first pole here can be a positive electrode or a negative electrode.
  • the air bag 5 is made of low-density polyethylene.
  • the gas bag 5 contains the gas to be detected, and the gas to be detected may be helium.
  • the diameter of the air bag 5 is smaller than the vertical distance from the first end of the first tab 4 to the first end of the cell 1 after sealing. Because the helium molecules are small, the helium molecules can penetrate the low-density air bag 5 and escape into the cavity 7. After a certain period of time (for example, 48 hours), the helium molecules will escape into the cavity 7. At this time, the lithium battery is placed in the sealed chamber of the airtightness testing instrument, and the lithium battery is determined by detecting whether there is helium leakage. Whether the battery's sealing performance is qualified.
  • the instrument does not detect helium, it is judged that the sealing performance of the lithium battery is qualified.
  • the space occupied by the air bag is smaller than the vertical distance from the first end of the first tab 4 to the first end of the battery cell 1, the structure of the lithium battery will not be changed, and the sealing operation of the lithium battery will not be affected. Convenience and safety of the sealing inspection of lithium batteries.
  • the air bag 5 containing the gas to be tested is placed in the cavity 7 between the first end of the cell 1 and the first end cap 2. Then, the lithium battery is sealed. As shown in FIG. 5, the lower part of the casing 3 surrounds the cell 1, and the top of the casing 3 exceeds the first pole cap 2 and the edge is bent toward the direction of the first pole cap 2 to form an obtuse angle. After the lithium battery is sealed twice, as shown in FIG. 6, the top edge of the housing 3 is in contact with the edge of the first pole cap 2, and the top edge of the housing 3 is pressed against the edge of the first pole cap 2.
  • a vertical downward force F is applied to the top of the first pole cap 2, and the first pole cap 2 drives the first pole ear 4 to move vertically downward for a distance L, and the air bag 5 ruptures due to pressure, thereby The gas to be tested is released in the cavity 7.
  • the first end of the lithium battery contains the gas to be tested, and then the sealed battery is placed on a special testing instrument for testing. By detecting whether the gas to be tested overflows, it can be judged whether the battery is completely sealed.
  • the gas bag 5 with the tested gas is crushed by the process of encapsulating the lithium battery to realize the function of injecting the tested gas into the internal cavity 7 of the battery.
  • the operation is very simple and no existing battery is needed.
  • the packaging production line also eliminates the supporting equipment required in the prior art for injecting the gas to be inspected after packaging, and the production cost is low, and the battery can be directly placed in the special detector for the gas to be inspected in the prior art. Detection.
  • the diameter of the gas bag 5 after being filled with the gas to be tested is R
  • the vertical distance from the first end of the first tab 4 to the first end of the battery cell 1 after the lithium battery is sealed is H, then R is greater than H.
  • the air bag 5 is placed under the first end of the first tab 4, and then during the packaging process, the first end of the first tab 4 moves downward by a distance L, so as to finally make the first tab
  • the distance between the first end and the second end of 4 is H.
  • the diameter of the air bag 5 is larger than H, the air bag 5 will be crushed, and the gas bag 5 can be crushed to release the detected gas through the packaging process of the lithium battery itself.
  • the first tab 4 of this embodiment has a C-shaped structure, and the first end is connected to the bottom of the first pole cap 2, and the second end is connected to the first end of the cell 1.
  • This arrangement is because when the first end surface of the first tab 4 is pressed downward by the first pole cap 2, the first end will gradually approach the second end, so that there is a gap between the housing 3 and the first pole cap 2.
  • the sealed connection reserves a certain vertical distance.
  • the first tab 4 is an elastic metal sheet. With this arrangement, the first pole lug 4 can realize the connection between the two ends of the first pole cap 2 and the first pole of the cell 1 respectively, and at the same time, it will not be easily crushed during the battery packaging process.
  • the air bag 5 of this embodiment is all placed between the first end and the second end of the first tab 4.
  • the air bag 5 when the first end of the first tab 4 is close to the second end, the first end is vertically pressed down on the air bag 5, and when the pressure reaches a certain level, the air bag 5 will rupture and be The test gas is released in the cavity 7. Since the air bag 5 is placed between the first end and the second end, and the first end is subjected to the vertical downward pressure of the first pole cap 2, the air bag 5 will also be subjected to the vertical downward pressure during the sealing process. , So as to achieve smoothly be crushed and release the detected gas. In other embodiments, the air bag 5 may also be partially placed between the first end and the second end of the first tab 4.
  • the top middle part of the first pole cap 2 of this embodiment protrudes outwardly to form a first pole cap as a whole.
  • the bottom side of the first pole cap 2 of this embodiment is provided with a sharp corner 6 protruding downward, and the sharp corner 6 is pressed against the top of the first end of the first pole lug 4.
  • This arrangement can increase the vertical pressure of the bottom side of the first pole cap 2 on the first end surface of the first pole lug 4 to increase the probability of crushing the air bag 5.
  • the first pole cap 2 is connected and sealed with the edge of the housing 3.
  • the gas bag 5 is crushed to make the gas to be detected Released in the cavity 7.
  • the sealing action between the first pole cap 2 and the housing 3 during the battery packaging process can be used to crush the gas bag 5 containing the gas to be tested, which can be used for subsequent detection of whether there is a leak of the gas to be tested to further determine the sealing of the battery . No additional injection of the gas to be detected is required, which reduces the cost of the detection process and reduces the operation steps.
  • the gas to be detected is helium. It can be understood that, in other embodiments, the gas to be tested may also be one or a combination of nitrogen, hydrogen, neon, argon, krypton, xenon, and radon.
  • the air bag 5 is spherical, and in other embodiments, it may also be elliptical or square.

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  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Sealing Battery Cases Or Jackets (AREA)

Abstract

本发明涉及一种锂电池及锂电池的气密检测方法。锂电池包括电池本体，电池本体上开设有注液孔以及与注液孔连通的注液口；密封塞，与注液孔密封配合；补焊片，与注液口焊接密封；气袋，气袋内部包含被检气体，气袋设置于密封塞与补焊片之间；当所述补焊片焊接密封于所述注液口时，所述气袋能够熔破以使所述被检气体被释放至所述密封塞与所述补焊片之间。

Description

锂电池及锂电池的气密检测方法 技术领域
本发明涉及电池密封性检测技术领域，特别是涉及一种锂电池及锂电池的气密检测方法。
背景技术
锂电池凭借其能量密度大、输出功率高、充放电寿命长、可快速充电、绿色无污染、工作温度范围宽及自放电小等诸多优点而备受关注。
锂电池内部化学体系性质活泼，非常容易与外界的水分和空气发生副反应导致电池性能退化或失效，故封装气密性对于锂电池的可靠性、安全性是至关重要的。如何有效检测锂电池气密性，确保封装不良品不会流入消费市场，具有非常重要的意义。
目前，部分锂电池在注液后会使用胶塞将注液口封闭，以确保电池内部保持一定的真空度，然后在注液口上方激光焊接密封铝片实施密封。因为胶塞的密封性，导致预先注入电池内部的检测气体无法进入胶塞与密封铝片之间的空间，从而无法检测密封铝片的焊接气密性。
发明内容
一种锂电池，包括电池本体，所述电池本体上开设有注液孔以及与所述注液孔连通的注液口；密封塞，与所述注液孔密封配合；补焊片，与所述注液口焊接密封；气袋，所述气袋设置于所述密封塞与所述补焊片之间，所述 气袋内部包含被检气体；其中，当所述补焊片焊接密封于所述注液口时，所述气袋能够熔破以使所述被检气体被释放至所述密封塞与所述补焊片之间。
在其中一个实施例中，所述密封塞的顶部设有凹槽，所述气袋放置于所述凹槽内。
在其中一个实施例中，所述密封塞的顶部设有供所述密封塞旋入所述注液孔的十字形凹槽或一字形凹槽；所述凹槽至少部分设置于所述十字形凹槽或一字型凹槽。
在其中一个实施例中，所述气袋至少部分凸设于所述密封塞。
在其中一个实施例中，所述密封塞为弹性密封塞或者所述气袋为弹性气袋；所述气袋至少部分凸设于所述注液口。
在其中一个实施例中，所述密封塞包括圆柱形本体及锥头，所述锥头设置于所述圆柱形本体一端。
在其中一个实施例中，所述被检气体为选自氮气、氢气及惰性气体中的至少一种；所述惰性气体为氦气、氖气、氩气、氪气、氙气或氡气。
在其中一个实施例中，所述气袋形状为球形、椭圆球形或方形。
在其中一个实施例中，所述气袋的材质选自PP、PE、PET及PVC中的至少一种。
一种锂电池的气密检测方法，包括：提供一电池本体，所述电池本体上开设有注液孔以及与所述注液孔连通的注液口；将密封塞与所述注液孔密封配合；将气袋放置于所述密封塞上，所述气袋内部包含被检气体；将补焊片焊接至所述注液口，以与所述注液口密封配合，其中，焊接所述补焊片时产生的热量使所述气袋熔破，以使所述被检气体被释放至所述补焊片与所述密封塞之间；检测所述锂电池是否有所述被检测气体逸出。
根据上述锂电池及其气密检测方法，在对注液口进行注入电解液完成后，向注液孔中塞入密封塞，在向注液口处焊接补焊片之前，先将气袋放置于密封塞上，再将补焊片对应于注液口进行焊接密封。此时，焊接产生大量热量，该热量使得气袋被加热，进而熔破释放被检气体至密封塞与补焊片之间。通过气密检测设备对锂电池进行气密检测，检测是否有被检气体泄露，则可判断补焊片处是否密封良好。
一种锂电池，包括电芯、外壳、第一极盖帽、第一极耳和气袋，所述第一极盖帽置于所述电芯的第一极端，所述第一极盖帽的边缘与所述外壳的边缘连接并包裹所述电芯，所述第一极耳置于所述电芯的第一极端和所述第一极盖帽之间的空腔内，所述气袋设置于所述电芯的第一极端和所述第一极盖帽之间的空腔内，所述气袋内包含被检气体，其中，所述第一极盖帽竖直向下朝向所述第一极耳移动时压破所述气袋，以使所述被检气体释放在所述空腔内。
在其中一个实施例中，所述第一极耳为C型结构，且所述第一极耳的第一端与所述第一极盖帽的底部相接，所述第一极耳的第二端与所述电芯的第一极端相接。这样设置，因为到第一极耳第一端表面受到第一极盖帽向下的压力时，第一端会逐渐与第二端靠近，这样给外壳与第一极盖帽之间的密封连接预留了一定的竖向距离。
在其中一个实施例中，所述气袋至少部分置于所述第一极耳的第一端和第二端之间。这样设置，在第一极耳的第一端靠近第二端的过程中，第一端竖直向下压在气袋上，当压力达到一定程度时，气袋将会破裂并将被检气体释放在空腔内。由于气袋放置在第一端和第二端之间，而第一端受到第一极盖帽竖直向下的压力，因此气袋也会在密封过程中受到竖直向下的压力，从 而实现顺利被压破并释放被检气体。
在其中一个实施例中，所述第一极盖帽的顶部中部整体向外侧突起形成第一极帽。
在其中一个实施例中，所述第一极盖帽的底侧设置有向下突起的尖角，所述尖角压在所述第一端的顶部。这样设置，可以提高第一极盖帽底侧竖向压在第一极耳第一端表面上的压强，以提高压破气袋的效率。
在其中一个实施例中，所述第一极耳为弹性金属片。这样设置，第一极耳可以实现两端分别与第一极盖帽和电芯的第一极端的连接，同时在电池封装过程中不会轻易被压断。
在其中一个实施例中，所述第一极盖帽与所述外壳的边缘连接密封。这样可以利用电池封装过程中第一极盖帽与外壳的密封动作，将含有被检气体的气袋压破，从而用于后续检测是否有被检气体泄漏，以进一步判断电池的密封性。
在其中一个实施例中，所述被检气体选自氮气、氢气及惰性气体中的至少一种。
在其中一个实施例中，所述气袋为球形、椭圆形或方形。
在其中一个实施例中，所述气袋充满被检气体后的直径大于锂电池密封后所述第一极耳的第一端至所述电芯的第一极端的垂直距离；或者被检气体为氦气且气袋的直径小于密封后第一极耳的第一端至电芯的第一极端的垂直距离。这样可以保证在密封过程中，气袋被第一极耳的第一端压破从而释放出被检气体；或者氦气分子穿透低密度的气袋并逃逸到空腔中。这样锂电池的第一极端和第一极盖帽之间的空腔内含有被检气体，接着将密封好的电池置于专用的气体检测仪器上进行测试，检测是否有被检气体溢出，则可判断 该电池是否完全密封好。本方案中，实现将被检气体注入第一极端和第一极盖帽之间的空腔内的作用，操作非常简单，而且无需改造已有的电池的封装生产线，也免去了现有技术中封装后再注入被检气体所需的配套设备，生产成本低，而且后续可以将电池直接置于现有技术中的被检气体的专用检测仪中检测。
上述锂电池，通过将含有被检气体的气袋放在密封前的第一极盖帽下方，并通过第一极盖帽和外壳密封过程的竖向运动所带来的压力将气袋压破，实现将被检气体释放在封装后的电池内。气袋所占的空间小，且无需改变锂电池的结构，而且操作过程简单，后续检测可靠，提高了锂电池的密封检测工作的便捷性以及安全性。
附图说明
为了更清楚地说明本申请实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他实施例的附图。
图1为一实施例中的锂电池的结构示意图。
图2为图1所示的锂电池的另一视角的结构示意图。
图3为图2所示的锂电池的A处局部放大结构示意图。
图4为一实施例中的锂电池的密封塞的结构示意图。
图5为一实施例中的锂电池的封装过程示意图。
图6为一实施例中的锂电池的封装过程示意图。
图7为一实施例中的锂电池的封装完成示意图。
具体实施方式
为了便于理解本发明，下面将参照相关附图对本发明进行更全面的描述。附图中给出了本发明的较佳的实施例。但是，本发明可以以许多不同的形式来实现，并不限于本文所描述的实施例。相反地，提供这些实施例的目的是使对本发明的公开内容的理解更加透彻全面。
除非另有定义，本文所使用的所有的技术和科学术语与属于本发明的技术领域的技术人员通常理解的含义相同。本文中在本发明的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本发明。本文所使用的术语“及/或”包括一个或多个相关的所列项目的任意的和所有的组合。
在描述位置关系时，除非另有规定，否则当一元件被指为在另一元件“上”时，其能直接在其他元件上或亦可存在中间元件。亦可以理解的是，当元件被指为在两个元件“之间”时，其可为两个元件之间的唯一一个，或亦可存在一或多个中间元件。
在使用本文中描述的“包括”、“具有”、和“包含”的情况下，除非使用了明确的限定用语，例如“仅”、“由……组成”等，否则还可以添加另一部件。除非相反地提及，否则单数形式的术语可以包括复数形式，并不能理解为其数量为一个。
此外，附图并不是1：1的比例绘制，并且各元件的相对尺寸在附图中仅以示例地绘制，而不一定按照真实比例绘制。
为了便于理解本发明的技术方案，在详细展开说明之前，首先对现有锂电池的气密检测进行说明。
现有锂电池的气密检测方式是在对电池注液完成后注入氦气，在注液口处塞上胶塞，接着放入气密检测设备进行气密检测。
通常，胶塞在塞入注液孔后，因为胶塞是弹性的，故会有应力释放，此时，胶塞会塞的非常紧，泄漏量极微，故在注液口处进行二次铝片焊接密封时，氦气无法从胶塞处逸出至焊接铝片与胶塞之间的空间，故无法有效检测铝片是否完成了对注液口的密封。
另外，在后续锂电池的使用过程中，也会存在因胶塞密封失效的情况，例如因电解液在释放锂离子与极片发生化学反应后，会产生复杂的气体，电池内部压力增大，促使胶塞向外膨胀松懈而导致胶塞无法正常密封，或者胶塞受电解液腐蚀性作用而老化导致胶塞无法正常密封等，故此时若铝片存在焊接不良情况，而造成电池泄露，不仅会影响电池的正常使用，同时也存在燃烧爆炸的隐患。
因此，需要提供一种可对铝片处进行气密检测，而使得电池气密性可靠的锂电池及其气密检测方法。
如图1和图2所示，一实施例中的锂电池100，包括电池本体10、密封塞20(见附图3)、补焊片30及气袋40(见附图3)。
电池本体10上开设有注液孔11及与注液孔连通的注液口12。密封塞20与注液孔11密封配合。补焊片30与注液口12焊接密封。气袋40内部包含被检气体。气袋40设置于密封塞20与补焊片30之间。当补焊片30焊接密封于注液口12时，在热量的作用下，气袋40能够熔破以使被检气体被释放至密封塞20与补焊片30之间。
这样，在对注液口12进行注入电解液完成后，向注液孔11中塞入密封塞，在向注液口12处焊接补焊片30之前，先将气袋40放置于密封塞20上， 再将补焊片30对应于注液口12进行焊接密封。此时，焊接产生大量热量，该热量使得气袋40被加热，进而熔破释放被检气体至密封塞20与补焊片30之间。通过气密检测设备对锂电池100进行气密检测，检测是否有被检气体泄露，即可判断补焊片30处是否密封良好。
上述锂电池100可检测补焊片30是否完成了对注液口12的密封，并且检测方式和操作简单，故可保证锂电池100的使用可靠性和安全性。另外，因气袋40所占空间小，无需改变现有锂电池的结构，故可以有效降低使用本方案的成本。
在一实施例中，电池本体10包括壳体13及盖设于壳体13一侧的盖板14。壳体13内部具有卷绕或层叠的隔膜材料。盖板14上设有正电极141、负电极142及安全部件143。如图3所示，在本实施例中，注液孔11贯穿盖板14，注液口12位于盖板14的外侧表面。补焊片30覆盖在注液口12上。
在一些实施例中，注液孔11为沉孔，密封塞20至少部分位于沉孔的台阶处。
如图3和图4所示，在一些实施例中，密封塞20的顶部设有凹槽，气袋40放置于凹槽内。因密封塞20顶部与补焊片30之间的间隙尺寸小，故设置凹槽可提供容纳气袋40的一定空间，从而增加气袋40中存放被检气体的容量，进而使气袋40熔破释放出达到设备检查所需的被检气体，因此，提高气密检测的准确性。具体地，该凹槽的形状可为半球形或其他与气袋40外形形状相匹配的形状，在此不作限制。
在一些实施例中，密封塞20的顶部设有供密封塞20旋入注液孔11的十字形凹槽或一字形凹槽，凹槽至少部分设置于该十字形凹槽或一字形凹槽。在密封塞20的顶部设置十字形凹槽或一字形凹槽，可方便密封塞20在有限 的空间中被操作而与注液孔11密封配合。凹槽至少部分设置于十字形凹槽或一字形凹槽，在不阻碍密封塞20旋入的同时，也节省了空间。应当理解的是，可使用螺丝刀与密封塞20顶部的十字形凹槽或一字形凹槽配合，而使密封塞20被旋入与注液孔11密封配合。
进一步地，凹槽可设置于十字形凹槽或一字形凹槽的中心位置。
请再次参阅图4，在一些实施例中，密封塞20包括圆柱形本体22及锥头23，锥头23设置于圆柱形本体22的一端。利用锥头23可方便密封塞20进入注液孔11完成密封配合，圆柱形本体22的形状简单，可为气袋40的放置提供更多的空间，例如，当注液孔11为沉孔时，密封塞20可完全进入沉孔的通孔部分，而不设置于沉头处。在其他实施例中，密封塞20也可呈钉状，在此不作限制。
请再次参阅图3，在一些实施例中，气袋40至少部分凸设于密封塞20。如此，可使气袋40的体积增大，从而增加气袋40中的被检气体的容量，进而使气袋40熔破释放的被检气体增多，提高气密检测的准确性。
在一些实施例中，密封塞20为弹性密封塞。在另一些实施例中，气袋40为弹性气囊。气袋40至少部分凸设于注液口12。在将补焊片30对注液口12进行焊接之前，先要将补焊片30固定于注液口12对应的焊接位置。若气袋40至少部分凸设于注液口12，设置密封塞20为弹性密封塞或者气袋40为弹性气囊，可在气袋40被压紧时，气袋40发生弹性形变或气袋40促使弹性密封塞20发生弹性变形，从而不影响补焊片20在注液口12对应的焊接位置的固定，因此，可进一步增大气袋40的体积，从而增加气袋40中存放被检气体的容量，提高气密检测的准确性。
在一些实施例中，气袋40的形状为球形、椭圆形或方形。本实施例中， 气袋40的形状为椭圆形。
在一些实施例中，气袋40的材质为PP(聚丙烯)、PE(聚乙烯)、PET(聚对苯二甲酸乙二醇酯)或PVC(聚氯乙烯)中的一种或多种组合。本实施例中，气袋40的材质为PP。应当理解的是，气袋40的材质应当不与电池本体10内的物质(例如电解液)发生任何化学反应。
在一些实施例中，被检气体为氮气、氢气或惰性气体中的一种或多种组合，惰性气体为氦气、氖气、氩气、氪气、氙气或氡气。本实施例中，被检气体为氦气。
基于上述的锂电池100，还提供一实施例的锂电池的气密检测方法，包括以下步骤：
S110：提供一电池本体10，电池本体10上开设有注液孔11及与注液孔11连通的注液口12。
注液孔11可贯穿电池本体10的盖板14，注液口12位于盖板14的外侧表面。
S120：将密封塞20与注液孔11密封配合。
密封塞20可为弹性密封塞，密封塞20的顶部设有供密封塞20旋入注液孔11的十字形凹槽或一字形凹槽，可利用起子与密封塞20顶部的十字形凹槽或一字形凹槽配合，而使密封塞20被旋入与注液孔11密封配合。
在一些实施例中，密封塞20包括圆柱形本体22及锥头23，锥头23设置于圆柱形本体22的一端。利用锥头23可方便密封塞20进入注液孔11完成密封配合。在其他实施例中，密封塞20也可呈钉状，在此不作限制。
S130：将气袋40放置于密封塞20上，气袋40内部包含被检气体。
气袋40的形状为球形、椭圆形或方形，本实施例中，气袋40的形状为 椭圆形。
气袋40的材质为PP(聚丙烯)、PE(聚乙烯)、PET(聚对苯二甲酸乙二醇酯)或PVC(聚氯乙烯)中的一种或多种组合。本实施例中，气袋40的材质为PP。
被检气体为氮气、氢气或惰性气体中的一种或多种组合，惰性气体为氦气、氖气、氩气、氪气、氙气或氡气。本实施例中，被检气体为氦气。
在一些实施例中，密封塞20的顶部设有凹槽，气袋40放置于凹槽内。进一步地，凹槽至少部分设置于十字形凹槽或一字形凹槽。
S140：将补焊片30焊接至注液口12，以与注液口12密封配合。当补焊片30焊接密封于注液口12时，焊接补焊片30时产生的热量使气袋40熔破，以使被检气体被释放至补焊片30与密封塞20之间。
气袋40至少部分凸设于密封塞20，更进一步地，密封塞20为弹性密封塞或者气袋40为弹性气囊，气袋40至少部分凸设于注液口12。
S150：检测锂电池100是否有被检测气体逸出。
可通过气体检测设备检测锂电池100是否有被检测气体逸出。具体地，气体检测设备可以为真空箱检漏设备，包括具有真空腔室的真空箱、抽真空设备及检漏仪。将经步骤S140后的锂电池100放置于真空箱的真空腔室中，再利用抽真空设备对真空腔室进行抽真空，此时，查看检漏仪有无被检气体泄露情况。
本实施例的锂电池100及锂电池气密检测方法，相比现有技术具有以下优点：
(1)、通过设置气袋40在密封塞20与补焊片30之间，利用补焊片30的热量熔破气袋40，从而释放被检气体至密封塞20与补焊片30之间，可检 测补焊片30是否完成了对注液口12的密封，提高锂电池100的使用可靠性和安全性；
(2)、通过在密封塞20顶部设有凹槽，气袋40放置于凹槽内，可弥补密封塞20顶部与补焊片30之间的间隙尺寸小，提供容纳气袋40的一定空间，从而增加气袋40中存放被检气体的容量，进而提高气密检测的准确性；
(3)、通过设置密封塞20的顶部设有供密封塞20旋入注液孔11的十字形凹槽或一字形凹槽，凹槽至少部分设置于十字形凹槽或一字形凹槽，在不阻碍密封塞20旋入的同时，也节省了空间；
(4)、通过设置密封塞20包括圆柱形本体22及锥头23，当注液孔11为沉孔时，密封塞20可完全进入沉孔的通孔部分，而不设置于沉头处，故可为气袋40的放置提供更多的空间；
(5)、通过设置密封塞20为弹性密封塞或者气袋40为弹性气囊，气袋40至少部分凸设于注液口12，在不影响补焊片20在注液口12对应的焊接位置的固定，可进一步增大气袋40的体积，提高气密检测的准确性。
参考附图5至附图6，一实施例中的锂电池，包括电芯1、外壳3、第一极盖帽2、第一极耳4和气袋5。第一极盖帽2置于电芯1的第一极端，第一极盖帽2的边缘与外壳3的边缘连接并包裹电芯1。第一极耳4置于电芯1的第一极端和第一极盖帽2之间的空腔7内。气袋5设置于电芯1的第一极端和第一极盖帽2之间的空腔7内。气袋5内包含被检气体。这里的第一极可以为正极，也可以为负极。
在一实施例中，气袋5采用低密度的聚乙烯材质制成。气袋5内含有被检气体，被检气体可为氦气。气袋5的直径小于密封后第一极耳4的第一端 至电芯1的第一极端的垂直距离。由于氦气分子小，因此氦气分子可以穿透低密度的气袋5并逃逸到空腔7中。经过一定时间(例如48小时)之后，氦气分子将逃逸至空腔7中，此时再将锂电池置于气密性检测仪器的密封室中，通过检测是否有氦气泄漏，来判定锂电池的密封性能是否合格。若仪器未检测到氦气，则判定锂电池的密封性能合格。这样设置，由于气袋所占的空间小于第一极耳4的第一端至电芯1的第一极端的垂直距离，不会改变锂电池的结构，不影响锂电池的密封操作，提高了锂电池的密封检测工作的便捷性以及安全性。
在锂电池进行封装前，将内含有被检气体的气袋5放置到电芯1的第一极端和第一极盖帽2之间的空腔7内。然后进行封装，锂电池一封后，如图5所示，外壳3的下部包围电芯1，外壳3的顶部超过第一极盖帽2并且边缘朝向第一极盖帽2所在方向弯折形成钝角。锂电池二封后，如图6所示，外壳3顶部边缘与第一极盖帽2的边缘接触，外壳3的顶部边缘被压紧在第一极盖帽2的边缘。此时在第一极盖帽2的顶部施加竖直向下的力F，第一极盖帽2带动第一极耳4朝竖直向下移动一段距离L，气袋5因受到压力而破裂，从而将被检气体释放在空腔7内。这样锂电池的第一极端内部含有被检气体，接着将密封好的电池置于专用检测仪器上进行测试，通过检测是否有被检气体溢出，则可判断该电池是否完全密封好。
本实施例中，利用锂电池封装的过程将带有被检气体的气袋5压破，以实现将被检气体注入电池内部空腔7中的作用，操作非常简单，而且无需已有的电池的封装生产线，也免去了现有技术中封装后再注入被检气体所需的配套设备，生产成本低，而且后续可以将电池直接置于现有技术中的被检气体的专用检测仪中检测。
参见附图7，在本实施例中，令气袋5充满被检气体后的直径为R，锂电池密封后第一极耳4的第一端至电芯1的第一极端的垂直距离为H，则R大于H。这样在电池封装前，将气袋5放在第一极耳4的第一端下方，然后在封装过程中，第一极耳4第一端朝下移动距离L，从而最终使得第一极耳4的第一端和第二端的距离为H。在此过程中，由于气袋5直径大于H，气袋5将被压破，通过锂电池自身的封装过程即可实现压破气袋5释放出被检气体。
参见附图5，本实施例的第一极耳4为C型结构，且第一端与第一极盖帽2的底部相接，第二端与电芯1的第一极端相接。这样设置，因为当第一极耳4的第一端表面受到第一极盖帽2向下的压力时，第一端会逐渐与第二端靠近，这样给外壳3与第一极盖帽2之间的密封连接预留了一定的竖向距离。在另一实施例中，第一极耳4为弹性金属片。这样设置，第一极耳4可以实现两端分别与第一极盖帽2和电芯1的第一极端的连接，同时在电池封装过程中不会轻易被压断。
参见附图5所示，本实施例的气袋5全部置于第一极耳4的第一端和第二端之间。这样设置，在第一极耳4的第一端靠近第二端的过程中，第一端竖直向下压在气袋5上，当压力达到一定程度时，气袋5将会破裂并将被检气体释放在空腔7内。由于气袋5放置在第一端和第二端之间，而第一端受到第一极盖帽2竖直向下的压力，因此气袋5也会在密封过程中受到竖直向下的压力，从而实现顺利被压破并释放被检气体。在其他实施例中，气袋5也可以部分置于第一极耳4的第一端和第二端之间。
参见附图6，本实施例的第一极盖帽2的顶部中部整体向外侧突起形成第一极帽。
参见附图5，本实施例的第一极盖帽2的底侧设置有向下突起的尖角6， 尖角6压在第一极耳4的第一端的顶部。这样设置，可以提高第一极盖帽2底侧竖向压在第一极耳4的第一端表面上的压强，以提高压破气袋5的几率。
参见附图5，本实施例中，第一极盖帽2与外壳3的边缘连接密封，第一极盖帽2竖直向下朝向第一极耳4移动时压破气袋5以使被检气体释放在空腔7内。这样可以利用电池封装过程中第一极盖帽2与外壳3的密封动作，将含有被检气体的气袋5压破，从而用于后续检测是否有被检气体泄漏，以进一步判断电池的密封性。无需额外进行被检气体的注入，降低了检测过程的成本，减少了操作步骤。
在本实施例中，被检气体为氦气。可以理解，在其他实施例中，被检气体也可以为氮气、氢气、氖气、氩气、氪气、氙气和氡气中的一种或多种的组合。
在本实施例中，气袋5为球形，在其他实施例中也可以为椭圆形或方形。
以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。
以上所述实施例仅表达了本发明的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对发明专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本发明构思的前提下，还可以做出若干变形和改进，这些都属于本发明的保护范围。因此，本发明专利的保护范围应以所附权利要求为准。

Claims (20)

  1. 一种锂电池，包括：
    电池本体，所述电池本体上开设有注液孔以及与所述注液孔连通的注液口；密封塞，与所述注液孔密封配合；
    补焊片，与所述注液口焊接密封；及
    气袋，所述气袋设置于所述密封塞与所述补焊片之间，所述气袋内部包含被检气体；
    其中，当所述补焊片焊接密封于所述注液口时，所述气袋能够熔破以使所述被检气体被释放至所述密封塞与所述补焊片之间。
  2. 根据权利要求1所述的锂电池，其特征在于，所述密封塞的顶部设有凹槽，所述气袋放置于所述凹槽内。
  3. 根据权利要求2所示的锂电池，其特征在于，所述密封塞的顶部设有供所述密封塞旋入所述注液孔的十字形凹槽或一字形凹槽，所述凹槽至少部分设置于所述十字形凹槽或一字型凹槽。
  4. 根据权利要求1所述的锂电池，其特征在于，所述气袋至少部分凸设于所述密封塞。
  5. 根据权利要求1所述的锂电池，其特征在于，所述密封塞为弹性密封塞，或者所述气袋为弹性气袋，所述气袋至少部分凸设于所述注液口。
  6. 根据权利要求1所述的锂电池，其特征在于，所述密封塞包括圆柱形本体及锥头，所述锥头设置于所述圆柱形本体一端。
  7. 根据权利要求1所述的锂电池，其特征在于，所述被检气体选自氮气、氢气及惰性气体中的至少一种。
  8. 根据权利要求1所述的锂电池，其特征在于，所述气袋形状为球形、椭圆 球形或方形。
  9. 根据权利要求1所述的锂电池，其特征在于，所述气袋的材质选自聚丙烯、聚乙烯、聚对苯二甲酸乙二醇酯及聚氯乙烯中的至少一种。
  10. 一种锂电池的气密检测方法，包括：
    提供一电池本体，所述电池本体上开设有注液孔以及与所述注液孔连通的注液口；
    将密封塞与所述注液孔密封配合；
    将气袋放置于所述密封塞上，所述气袋内部包含被检气体；
    将补焊片焊接至所述注液口，以与所述注液口密封配合，其中，焊接所述补焊片时产生的热量使所述气袋熔破，以使所述被检气体被释放至所述补焊片与所述密封塞之间；及
    检测所述锂电池是否有所述被检测气体逸出。
  11. 一种锂电池，包括电芯、外壳、第一极盖帽、第一极耳和气袋，所述第一极盖帽置于所述电芯的第一极端，所述第一极盖帽的边缘与所述外壳的边缘连接并包裹所述电芯，所述第一极耳置于所述电芯的第一极端和所述第一极盖帽之间的空腔内，所述气袋设置于所述电芯的第一极端和所述第一极盖帽之间的空腔内，所述气袋内包含被检气体，其中，所述第一极盖帽竖直向下朝向所述第一极耳移动时压破所述气袋，以使所述被检气体释放在所述空腔内。
  12. 根据权利要求11所述的锂电池，其特征在于，所述第一极耳为C型结构，且所述第一极耳的第一端与所述第一极盖帽的底部相接，所述第一极耳的第二端与所述电芯的第一极端相接。
  13. 根据权利要求12所述的锂电池，其特征在于，所述气袋至少部分置于所 述第一端和所述第二端之间。
  14. 根据权利要求13所述的锂电池，其特征在于，所述第一极盖帽的顶部中部整体向外侧突起形成第一极帽。
  15. 根据权利要求14所述的锂电池，其特征在于，所述第一极盖帽的底侧设置有向下突起的尖角，所述尖角压在所述第一端的顶部。
  16. 根据权利要求15所述的锂电池，其特征在于，所述第一极耳为弹性金属片。
  17. 根据权利要求16所述的锂电池，其特征在于，所述第一极盖帽与所述外壳的边缘密封连接。
  18. 根据权利要求11所述的锂电池，其特征在于，所述被检气体选自氮气、氢气及惰性气体中的至少一种。
  19. 根据权利要求11所述的锂电池，其特征在于，所述气袋为球形、椭圆形或方形。
  20. 根据权利要求11所述的锂电池，其特征在于，所述气袋充满被检气体后的直径大于所述第一端至所述电芯的第一极端的垂直距离；或者被检气体为氦气且气袋的直径小于密封后所述第一端至电芯的第一极端的垂直距离。
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CN210837981U (zh) * 2019-09-23 2020-06-23 湖南弘毅科技有限公司 软包锂电池
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