JP2002117901A - Sealed battery and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed battery positively allowing leakage inspection. SOLUTION: In this sealed battery containing helium, after evacuating the interior of a battery can sealed expect for an electrolyte pouring hole, an electrolyte is poured in from the electrolyte pouring hole by pressurizing it with helium containing gas of a pressure equal to or more than the atmospheric pressure, and after pouring the electrolyte and injecting the helium containing gas, the electrolyte pouring hole is sealed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed battery, and more particularly to a sealed battery capable of inspecting for leakage of an electrolyte, and more particularly to a lithium ion battery capable of performing highly sensitive and reliable inspection. .

[0002]

2. Description of the Related Art In a sealed battery such as a lithium ion battery, after a battery element is housed in a battery can, a header provided with an external connection terminal, a safety valve, an electrolyte injection port, and the like are welded, and the electrolyte is injected. A sealed battery is manufactured by sealing the battery except for the opening and injecting the electrolyte from the electrolyte injection port, attaching a sealing piece to the electrolyte injection port, and sealing by laser welding.

[0003] In the manufacture of a sealed battery, due to poor welding at the time of sealing or poor caulking of an external connection terminal portion attached via an insulating member, electrolyte leaks or moisture in the outside air is reduced. May get inside the battery. In a sealed battery with poor sealing, there is a possibility that problems such as damage to equipment due to leakage of electrolyte and the like may occur along with deterioration of battery performance. For this reason, leaks are inspected to prevent batteries with poor sealing from being shipped.However, after charging, batteries that have been charged are visually inspected to check for dirt on the surface due to electrolyte leakage. A visual inspection to confirm was common. However, the inspection method based on human vision may cause variations due to individual differences among inspectors, and when there is a minute defective sealing, etc., the amount of leakage is extremely small, so the period of shipping However, it is difficult to find such a finely sealed battery with a poor sealing in the inspection where the inspection is limited, and there is a possibility that the battery may be problematic.

Therefore, an airtightness test method using an airtightness test apparatus that does not rely on human vision or the like has been proposed. For example,
Japanese Patent Application Laid-Open No. Hei 9-115555 proposes a method in which a battery under test is housed in a closed container and the pressure inside the closed container is measured after the internal gas is decompressed. The leaked battery was not detected in time and accurately. Japanese Patent Application Laid-Open No. 4-25738 discloses that in a battery assembling process, after a lid is attached to a battery tank, hydrogen is supplied under pressure into the battery tank, and leaking hydrogen is detected by a semiconductor gas sensor. Although an airtightness inspection device is described, it does not perform a leak inspection of a completed sealed battery in which an electrolyte is injected, and uses an explosive gas called hydrogen, which has a safety problem. . In Japanese Patent Application Laid-Open No. 11-307136, a cover for covering a joint between the battery case and the cover is attached after the cover is joined to the battery case, helium is supplied into the battery case, and air inside the cover is released. An airtightness test device that determines the airtightness by suctioning and detecting helium in the suctioned air is described.However, it is intended to inspect the joining between a battery case and a lid in a manufacturing process, and to measure an electrolytic solution. It was not intended to perform a leak inspection of the completed sealed battery after injection.

[0005]

SUMMARY OF THE INVENTION According to the present invention, it is possible to reliably find a small defective sealing portion of a sealed battery.
An object of the present invention is to provide a sealed battery, and an object of the present invention is to provide a method of manufacturing a sealed battery that reliably eliminates shipment of a battery having a poor sealing.

[0006]

The object of the present invention can be solved by a sealed battery containing helium therein. Further, in the method for manufacturing a sealed battery, after the inside of the sealed battery can is evacuated except for the electrolyte injection port, pressure is applied from the electrolyte injection port with a helium-containing gas at a pressure higher than the atmospheric pressure, and the electrolyte is discharged. This is a method for manufacturing a sealed battery in which an electrolyte injection port is sealed after an injection and a helium-containing gas are injected. This is a method for producing a sealed battery as described above, wherein the helium-containing gas is supplied with a pressing means for pressing a wall surface of the battery can to prevent deformation of the battery can. In the method for detecting leakage of a sealed battery, a method of detecting leakage of a sealed battery in which a helium-containing sealed battery is measured by a helium leak detection device to detect leakage. Further, the above sealed battery is a lithium ion battery.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is to manufacture a sealed battery containing helium by filling the sealed battery with helium and then closing the sealed battery in the process of assembling the sealed battery. By detecting the concentration of helium leaking from the type battery with a helium leak detection device,
It has been found that it is possible to reliably detect a sealed battery having a poor sealing. FIG. 1 is a diagram illustrating a process of manufacturing a sealed battery according to the present invention, and is a diagram illustrating an apparatus for injecting an electrolyte and helium into a battery can. The battery element 2 is housed in the battery can 1, and the opening at the top of the battery can 1 is provided with an electrolyte injection port 3, an external electrode take-out terminal 4, and a pressure release for preventing the battery from bursting when the pressure inside the battery rises. An injection nozzle 7 of an electrolyte injection device 6 is provided on the battery can 1 to which a lid 5 having a valve or the like is attached by a method such as laser welding. Liquid device 6
Is mounted. Injection nozzle 7
Has an air-tightness maintaining means such as an O-ring 8 and the like, and when pressed against the wall surface of the lid, airtightness is maintained. Further, the electrolyte injection device 6 includes an exhaust unit 9 for exhausting the inside of the battery can, and an exhaust valve 10 connecting the injection nozzle 7 and the exhaust unit 9. An electrolyte pot 11 for storing a predetermined amount of electrolyte is connected to the injection nozzle 7 via an electrolyte injection valve 12. The electrolyte pot 11 is connected to storage means 14 for the electrolyte 13. The supplied electrolyte supply means 15 is connected to the electrolyte supply valve 16.
Are coupled through. Helium supply means 17 is connected to the electrolyte pot 11 via a pressure valve 18.

FIG. 2 is a view for sequentially explaining the operation of the electrolytic solution and helium injecting apparatus of the present invention. FIG. 2 (A)
As shown in FIG. 1, a battery element is housed in a battery can 1 and a lid 5 having an electrolyte injection port 3 is attached to an upper opening of the battery can 1 by a method such as laser welding. To
The injection nozzle 7 of the electrolyte injection device 6 is hermetically attached to the electrolyte injection port 3 provided on the lid 5. Then, the exhaust valve 9 is operated to connect the liquid injection nozzle 7 and the exhaust unit 9.
0 is opened, the inside of the battery can is evacuated, and a predetermined amount of the electrolytic solution corresponding to the battery is poured into the electrolytic solution pot 11 from the electrolytic solution supply means 15 through the electrolytic solution supply valve 16.

Next, as shown in FIG. 2B, the exhaust valve 10 and the electrolyte supply valve 16 are closed, and the electrolyte injection valve 1 is closed.
Release 2. Since the inside of the battery can is depressurized, the pressure difference between the inside of the battery can and the electrolyte pot 11 starts the injection of the electrolyte into the battery can. When the injection of the electrolyte in the electrolyte pot 11 is started, as shown in FIG. 2C, the pressure valve connected to the helium supply means 17 is opened, and the electrolyte in the electrolyte pot 11 is changed to helium. The electrolyte is quickly injected into the battery can, helium is also dissolved and injected into the electrolyte, and is injected into the electrolyte as a gas from the electrolyte injection port. The inside of the battery is filled with a helium atmosphere. Also, when the electrolyte and helium are injected, the battery can is pressurized from the inside, and depending on the size and type of the battery can, a phenomenon such as the wall surface of the battery can expands and deforms occurs. When the battery can is pressurized, it is preferable to suppress deformation due to expansion of the battery can.

FIG. 3 is a view for explaining means for preventing deformation of the battery can. After the injection of the electrolyte from the electrolyte injection nozzle 7 is started, the pressure valve 18 is opened and the electrolyte pot 1 is opened.
The electrolyte solution in the battery can 1 is pressurized with helium, and the pressing means 20 presses the wall surface 21 of the battery can from both sides to prevent deformation of the wall surface 21 of the battery can 1. The pressure for pressing the wall surface of the battery can is a pressure corresponding to the pressure of the electrolytic solution injected into the battery can, and is preferably pressed at a pressure equal to the pressing force. The electrolyte and helium injection device of the present invention can be arbitrarily set depending on the type of the battery active material, the shape and the structure of the battery, etc., but the exhaust inside the battery can is reduced to 1.07 kPa to 1.33 kPa. After exhausting for 2 to 7 seconds, maintain the reduced pressure for about 2 seconds, after confirming that the degree of vacuum is stable and there is no leakage, etc., close the exhaust valve and start injecting the electrolyte, Four to ten seconds after the start of the electrolyte injection, the pressure valve is opened and pressurized with helium. Helium pressure is 0.0
It is preferably 8 MPa to 0.20 MPa.
For example, according to the electrolytic solution injection device of the present invention,
m, 30 mm in width, 1 mm in diameter provided on a battery with a thickness of 6 mm
Even if the viscous non-aqueous electrolyte is
It can be injected in seconds.

Further, helium may be mixed with other rare gases, or may be a mixture of nitrogen, carbon dioxide and the like. For this reason, it is preferable that the content of a rare gas such as helium is large, and among rare gases, helium having a small molecule is preferable because it easily passes through a fine leak site. In the above description, the method of introducing helium into the battery can simultaneously with the injection of the electrolyte by using helium as a pressurizing gas when the electrolyte is injected has been described. Injection of helium and injection of helium may be performed separately. In this case, a method of individually injecting helium from the injection port into the battery can after the injection of the electrolyte is provided, the battery can after the injection of the electrolyte is provided in a closed chamber, the closed chamber is evacuated, and the pressure is reduced. After that, injection can be performed by filling the closed chamber with helium and performing injection.

Next, a method for inspecting leakage of a sealed battery containing helium according to the present invention will be described. FIG. 4 is a diagram illustrating an example of the leak inspection method. As shown in FIG. 4A, a sealed battery 31 is manufactured by closing the electrolyte injection port 3 provided on the lid of the battery can 1 by laser welding means 30, and after initial charging is performed. , FIG. 4 (B)
As shown in FIG.
2, the helium leak detector 33 sucks the gas in the leak detection chamber 32 and measures the helium concentration to detect the presence or absence of battery leakage. Further, as shown in FIG. 4C, a pressure reducing device 34 is connected to the leak detection chamber 32 to reduce the pressure inside the leak detection chamber, thereby increasing the pressure difference between the inside and outside of the battery to be detected, thereby minimizing the difference. The leak rate from the leak location may be increased to facilitate leak inspection.

FIG. 5 is a diagram for explaining another example of the leak inspection method. In the leak detection chamber 32, the battery tray 3
5, a large number of sealed batteries 31 are accommodated and provided, installed in the leak detection chamber 32, and the helium leak detector 33 sucks the gas in the leak detection chamber 32 and measures the helium concentration to detect helium. In this case, each of the detected sealed batteries in the battery tray is set in the leak detection chamber 32 in the same manner as that shown in FIG. The leaked battery can be specified by measuring the helium concentration by sucking the gas in 32. FIG. 6 is a diagram illustrating another example of the leak inspection method. This is a method of checking the presence or absence of leakage by bringing the sniffer probe 36 of the helium leak detector 33 close to a location where leakage may occur, such as a welding location around the sealed battery 31, and checking by such a method. can do.

FIG. 7 is a perspective view for explaining another example of the leak detection method. The sealed battery 31 to be detected for leakage is accommodated in a plurality of detection tanks 38 provided on the detection tray 37. Detection heads 40 each having a leak detection probe 39 attached thereto are individually and hermetically attached to the detection tanks, and the presence or absence of leakage can be detected by measuring the helium concentration in each detection tank. After the detection head is mounted, the measurement may be performed by reducing the pressure in the detection tank. By attaching the detection head to a transporting means that can be moved to any position in the X, Y, and Z directions and providing a means for removing the battery in which the leak has been detected, the leak detecting process can be automatically performed. Become.

Further, the sealed battery containing helium of the present invention can be used as a non-aqueous electrolyte battery such as a lithium ion battery, a battery using a polymer electrolyte, a nickel hydride battery, a sealed lead battery and other aqueous electrolyte batteries. Can also be applied.

[0016]

According to the sealed battery containing helium of the present invention, a leak-proof place such as a sealing place of a sealed battery or a place where a conductive connection terminal is taken out can be reliably measured by a measuring device without variation. It is possible to eliminate the possibility that a battery with a leakage failure is accidentally shipped, and to increase the reliability of the shipped battery.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a process for manufacturing a sealed battery according to the present invention, and is a diagram illustrating an apparatus for injecting an electrolyte and helium into a battery can.

FIG. 2 is a diagram for sequentially explaining the operation of the electrolytic solution and helium injecting device of the present invention.

FIG. 3 is a diagram illustrating a means for preventing deformation of a battery can.

FIG. 4 is a diagram illustrating an example of a leakage inspection method.

FIG. 5 is a diagram illustrating another example of the leak inspection method.

FIG. 6 is a diagram illustrating another example of the leak inspection method.

FIG. 7 is a diagram illustrating another example of the leak inspection method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Battery can, 2 ... Battery element, 3 ... Electrolyte injection port, 4 ... External electrode extraction terminal, 5 ... Lid, 6 ... Electrolyte injection device,
7 ... injection nozzle, 8 ... O-ring, 9 ... exhaust means, 10
... exhaust valve, 11 ... electrolyte pot, 12 ... electrolyte injection valve,
13: electrolyte, 14: storage means, 15: electrolyte supply means, 16: electrolyte supply valve, 17: helium supply means, 1
8 ... pressurizing valve, 20 ... pressing means, 21 ... wall surface of battery can, 3
0: laser welding means, 31: sealed battery, 32: leak detection chamber, 33: helium leak detector, 34: pressure reducing device, 35: battery tray, 36: sniffer probe,
37: detection tray, 38: detection tank, 39: leak detection probe, 40: detection head

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Mizuno 484 Harigaya-cho, Utsunomiya-shi, Tochigi NAC Mobile Energy Corporation (72) Inventor Yuichi Maekawa 484 Harigaya-cho, Utsunomiya-shi, Tochigi NMC Mobile Energy F term in the company (reference)

Claims (4)

[Claims] 1. A sealed battery comprising helium therein. 2. A method for manufacturing a sealed battery, wherein the inside of a sealed battery can is evacuated except for an electrolyte injection port, and then pressurized with a helium-containing gas at a pressure higher than atmospheric pressure from the electrolyte injection port, A method for manufacturing a sealed battery, comprising: closing an electrolyte injection port after injecting an electrolyte and injecting a helium-containing gas. 3. The method for manufacturing a sealed battery according to claim 2, further comprising a pressing means for pressing a wall surface of the battery can to prevent deformation of the battery can when supplying the helium-containing gas. 4. A method for detecting leakage of a sealed battery, wherein the leakage is detected by measuring a sealed battery containing helium with a helium leak detection device.