JP2009026569A - Sealed battery airtightness inspection method and sealed battery - Google Patents

Abstract

An object of the present invention is to provide a hermetic inspection method for a sealed battery and a sealed battery that can easily and accurately evaluate the hermeticity of the sealed battery in a short time.
An airtight inspection method for a sealed battery according to the present invention includes a production step of manufacturing a sealed battery in a sealed container in a detection gas atmosphere, and after the detection gas in the sealed container is removed, A gas detection step of detecting the detection gas leaking from the sealed battery in the sealed container.
[Selection] Figure 1

Description

  The present invention relates to a sealed battery hermetic inspection method and a sealed battery technology.

  With the development of portable devices, electric tools, electric automobiles, etc., the demand for sealed batteries having high energy density and high output density is rapidly increasing. Generally, a sealed battery has a structure in which a lid and a container of a battery case containing a power generation element and an electrolyte solution are sealed through a sealing material. For example, a primary battery such as an alkaline manganese battery, lithium ion There are secondary batteries such as batteries and nickel metal hydride batteries.

  In the above sealed battery, maintaining the airtightness is extremely heavy from the viewpoint of safety in view of the storage characteristics of the battery. When the hermeticity of the sealed battery is not sufficiently maintained, for example, when the electrolyte leaks from the battery case and causes corrosion of the battery case or peripheral devices, or a predetermined discharge capacity cannot be secured. There are cases.

  Normally, when a manufactured sealed battery is sold, an airtight inspection is performed, and sealed batteries that are not sufficiently kept airtight are excluded. Various methods for hermetic inspection of sealed batteries have been proposed so far.

  FIG. 5 is a schematic diagram for explaining a conventional airtightness inspection method. A gas injection pipe 44 shown in FIG. 5 connects an outlet (not shown) of the high-pressure gas cylinder 46 and a gas inlet (not shown) provided in the sealed battery 4. The gas injection pipe 44 is provided with a pressure gauge 48 and a valve 50. In the airtight inspection of the sealed battery 4 of the conventional example, the valve 50 provided in the gas injection pipe 44 is opened, and the gas is sealed from the high pressure gas cylinder 46 through the gas injection pipe 44 and the gas injection port of the sealed battery 4. While being introduced into the battery 4, the pressure inside the sealed battery 4 is measured with a pressure gauge 48. Thereafter, the valve 50 was closed, the pressure change in the sealed battery 4 was measured with the pressure gauge 48, and it was determined that a gas leak occurred when a pressure drop was observed.

  Further, for example, in Patent Document 1, a closed battery after performing a charge / discharge test is disposed in a sealed container, and after the sealed container is placed in a reduced pressure atmosphere, the gas concentration flowing out from the sealed battery into the sealed container There has been proposed an airtight inspection method for a sealed battery that measures the above.

  In addition, for example, Patent Document 2 discloses that a lithium secondary battery is pressurized in a gas gas atmosphere of molecules smaller than water molecules, and the airtightness of the lithium secondary battery is evaluated based on the presence or absence of swelling of the lithium secondary battery. A method has been proposed.

  Further, for example, in Patent Document 3, a sodium-sulfur battery is manufactured in an inert gas atmosphere, the obtained sodium-sulfur battery is pressurized with helium gas, and helium gas leaks from the sodium-sulfur battery. There has been proposed an airtight inspection method for inspecting.

JP 2001-236986 A JP 2003-151642 A JP 2000-90966 A

  However, in the hermetic inspection method for the sealed battery 4 of the conventional example shown in FIG. 5 and the hermetic inspection method of Patent Document 3, it is necessary to provide a gas inlet for introducing gas into the sealed battery. In order to increase the accuracy of the inspection, it is necessary to ensure airtightness between the gas inlet and the gas injection pipe, and after the airtight inspection, it is necessary to close the inlet to prevent gas leakage from the inlet. In some cases, the implementation work cannot be easily performed.

  Further, in the hermetic inspection method for a sealed battery disclosed in Patent Document 1, it is necessary to perform a charge / discharge test to increase the gas pressure in the sealed battery, and the hermetic test may take a long time.

  Moreover, in the evaluation method of the lithium secondary battery of Patent Document 2, since the hermetic evaluation is performed based on whether or not the lithium secondary battery is swollen, there are cases where variations in the airtight inspection accuracy of the battery occur.

  Accordingly, an object of the present invention is to provide a hermetic inspection method for a sealed battery and a sealed battery that can evaluate the hermeticity of the sealed battery easily and accurately in a short time.

  The airtightness inspection method for a sealed battery according to the present invention includes a production step of producing a sealed battery in a sealed container in a detection gas atmosphere, and the sealed container under atmospheric pressure after removing the detected gas in the sealed container. And a gas detection step of detecting the detection gas leaking from the sealed battery.

  The hermeticity inspection method for a sealed battery according to the present invention is a manufacturing step for producing a sealed battery including a battery case in which a lid and a container are sealed via a sealing material having a recess in a sealed container in a detection gas atmosphere. And a gas detection step of detecting the detection gas leaking from the inside of the battery case or the inside of the recess in the sealed container at or below atmospheric pressure after the detection gas in the sealed container is removed.

  Further, the present invention is a sealed battery including a battery case in which a lid and a container are sealed via a sealing material, wherein the sealing material is at least one of the lid and the surface in contact with the container. On the other hand, a recess is provided, and when the lid body and the container are hermetically sealed, a detection gas for detecting gas leakage from the sealed battery is sealed in the recess.

  According to the present invention, a manufacturing step for producing a sealed battery in a sealed container in a detection gas atmosphere, and after removing the detected gas in the sealed container, leakage from the sealed battery in a sealed container at or below atmospheric pressure. By including the gas detection step of detecting the detection gas, it is possible to provide a hermetic inspection method for a sealed battery that can easily and accurately evaluate the hermeticity of the sealed battery in a short time.

  In addition, according to the present invention, there is provided a sealed battery including a battery case in which the lid and the container are sealed via the sealing material, wherein the sealing material is at least one of the surfaces in contact with the lid and the container. When the lid and container are sealed, a gas for detecting the gas leakage of the sealed battery is sealed in the recessed portion, so that the hermeticity of the sealed battery can be easily and accurately sealed in a short time. It is possible to provide a sealed battery that can be evaluated.

  Embodiments of the present invention will be described below.

  An airtight inspection method for a sealed battery according to the present embodiment includes a production step of producing a sealed battery in a sealed container in a detection gas atmosphere, and after removing the detected gas in the sealed container, And a gas detection step of detecting a detection gas leaking from the sealed battery.

  FIG. 1 is a schematic diagram for explaining an example of a hermetic inspection method for a sealed battery according to the present embodiment.

  In the airtight inspection of the sealed battery according to the present embodiment, for example, an inspection device 1 shown in FIG. 1 is used. The inspection apparatus 1 includes a sealed container 10, a detection gas cylinder 12, a pressure gauge 14, a vacuum pump 16, a detection gas introduction pipe 18, a vacuum exhaust pipe 20, valves 22 a and 22 b, and a gas sensor 24.

  The detection gas introduction pipe 18 connects an outlet (not shown) of the detection gas cylinder 12 and a gas introduction port (not shown) of the sealed container 10. The detection gas introduction pipe 18 is provided with a pressure gauge 14 and a valve 22a for detecting the pressure in the sealed container 10. The vacuum exhaust pipe 20 connects a gas suction port (not shown) of the vacuum pump 16 and a gas discharge port (not shown) of the sealed container 10, and the vacuum exhaust pipe 20 is provided with a valve 22 b. ing.

  Since the detection gas used in the present embodiment is introduced into the sealed battery 2, it needs to be a gas that does not affect the battery reaction of the sealed battery 2. The type of the detection gas may be appropriately selected depending on the type of the sealed battery 2 to be used, and examples thereof include rare gases such as helium and argon, hydrogen gas, and nitrogen gas. Moreover, it is preferable that it is a gas smaller than a water molecule at the point which can test | inspect the airtightness of the sealed battery 2 accurately, For example, hydrogen gas, helium gas, etc. are mentioned.

  The gas sensor 24 is for detecting a detection gas leaking from the sealed battery 2. The gas sensor 24 is provided in the vicinity of the gas discharge port of the sealed container 10 (where the vacuum exhaust pipe 20 described above is connected). If the detection gas leaking from the sealed container 10 can be detected, the gas sensor 24 is provided. The installation location is not particularly limited.

<Production step>
After the members constituting the sealed battery are provided in the sealed container 10, the valve 22b of the vacuum exhaust pipe 20 is opened, the vacuum pump 16 is operated, and the sealed container 10 is depressurized. The pressure in the sealed container 10 when the pressure is reduced is not particularly limited.

  After reducing the pressure of the sealed container 10 to a predetermined pressure, the vacuum pump 16 is stopped and the valve 22b of the vacuum exhaust pipe 20 is closed. Next, the valve 22a of the detection gas introduction pipe 18 is opened, the detection gas is introduced into the sealed container 10 from the detection gas cylinder 12, and the inside of the sealed container 10 is made a detection gas atmosphere. In order to make the inside of the sealed container 10 in the detection gas atmosphere in a short time, it is preferable to introduce the detection gas into the sealed container 10 after reducing the pressure of the sealed container 10 as described above, but this is not necessarily limited thereto. is not. For example, the air in the sealed container 10 may be exhausted from the vacuum exhaust pipe 20 while introducing the detection gas from the detection gas cylinder 12 to the sealed container 10 without reducing the pressure of the sealed container 10.

  Next, the sealed battery 2 is manufactured in the sealed container 10 in the detection gas atmosphere. The sealed battery 2 according to the present embodiment has a structure in which a lid and a container of a battery case are sealed via a sealing material. For example, a primary battery such as an alkaline manganese dry battery, a lithium ion secondary battery, or nickel hydride Secondary batteries such as secondary batteries.

  FIG. 2 is a schematic cross-sectional view showing an example of the configuration of the sealed battery according to the present embodiment. As shown in FIG. 2, the sealed battery 2 includes an electrode body 26 impregnated with an electrolytic solution, a battery case 28, and a sealing material 30.

The electrode body 26 is an electrochemical element of the sealed battery 2 for charging and discharging. The electrode body 26 is obtained by winding, laminating, etc., a positive electrode and a negative electrode (not shown) with a separator interposed therebetween. In the case of a lithium ion secondary battery, for example, the positive electrode is obtained by applying a positive electrode active material (for example, LiCoO ₂ ) to an aluminum foil, and the negative electrode is formed by applying a negative electrode active material (for example, graphite) to a copper foil. It has been applied. In addition, the separator electrically and physically separates the positive electrode and the negative electrode, and is, for example, a porous resin film such as a polyethylene resin film.

The electrolyte is appropriately selected according to the type of the sealed battery. In the case of a lithium ion secondary battery, for example, a solution obtained by dissolving LiPF ₆ in a mixed solvent of ethylene carbonate and dimethyl carbonate may be used. it can.

  The battery case 28 has a lid 32 and a container 34. The lid 32 is provided with electrode terminals 36a and 36b. The battery case is not particularly limited as long as it has corrosion resistance with respect to the electrolytic solution. For example, a metal such as aluminum or stainless steel is used.

  The material constituting the sealing material 30 is not particularly limited as long as it has elasticity in order to increase the airtightness between the lid 32 and the container 34. For example, silicone rubber or the like is used.

  A method for manufacturing the sealed battery 2 will be described. The positive electrode lead 38a is welded to the positive electrode constituting the electrode body 26 described above, and the negative electrode lead 38b is welded to the negative electrode. Next, the welded positive electrode lead 38 a is welded to the electrode terminal 36 a provided on the lid 32, and the welded negative electrode lead 38 b is welded to the electrode terminal 36 b provided on the lid 32. The electrode body 26 is impregnated with the electrolytic solution, and the electrode body 26 is accommodated in the container 34. A sealing material 30 is sandwiched between the lid 32 and the container 34 and sealed by caulking or the like. The above manufacturing method is an example, and is not necessarily limited thereto.

  Thus, by producing the sealed battery 2 in the sealed container 10 in the detection gas atmosphere, the detection gas can be sealed in the sealed battery 2 (in the battery case 28).

  In the present embodiment, since it is sufficient that the detection gas can be sealed in the sealed battery 2, the sealed battery 2 is manufactured in the sealed container 10, for example, only by sealing by caulking such as curling. It may be performed within.

<Gas detection step>
After manufacturing the sealed battery 2, the valve 22 b of the vacuum exhaust pipe 20 shown in FIG. 1 is opened, the vacuum pump 16 is operated, the detection gas in the sealed container 10 is removed, and then the valve 22 b of the vacuum exhaust pipe 20 is opened. The closed container 10 is closed to a reduced pressure atmosphere. Whether or not the sealed container 10 is depressurized is confirmed by the pressure gauge 14. Thereafter, the detection gas leaking from the sealed battery 2 is detected by the gas sensor 24. If the detection gas is not detected by the gas sensor 24, it can be determined that the sealed battery 2 is a good product.

  In the present embodiment, it is preferable that the inside of the sealed container 10 is in a reduced pressure atmosphere because the detection gas leaking from the inside of the sealed battery 2 can be detected in a short time. However, the present invention is not necessarily limited to this. .

  A gas sensor is provided with an open port (not shown) that communicates with the outside air in the sealed container 10, the detection gas in the sealed container 10 is removed by the vacuum pump 16, the open port is opened, and the closed container 10 is returned to atmospheric pressure. The detection gas leaking from the inside of the sealed battery 2 may be detected by 24.

  In the present embodiment, the gas sensor 24 is not necessarily used as long as the detection gas leaking from the sealed battery 2 can be detected.

  Next, an airtight inspection method for a sealed battery according to another embodiment of the present invention will be described.

  An airtight inspection method for a sealed battery according to another embodiment of the present invention includes a battery case including a battery case in which a lid and a container are sealed via a sealing material having a recess in a sealed container in a detection gas atmosphere. A manufacturing step for producing a battery and a gas detection step for detecting a detection gas leaking from a battery case or a recess in a sealed container at or below atmospheric pressure after removing the detected gas in the sealed container.

  In the airtight inspection of the sealed battery according to another embodiment of the present invention, for example, the inspection device 1 shown in FIG.

<Production step>
The same procedure as described above is performed except that the sealed battery is manufactured.

  FIG. 3 is a schematic cross-sectional view showing an example of the configuration of a sealed battery according to another embodiment of the present invention. As shown in FIG. 3, the sealed battery 3 includes an electrode body 26, a battery case 28, and a sealing material 40. The sealed battery 3 shown in FIG. 3 has the same configuration as the sealed battery 2 shown in FIG. 2 except for the sealing material 40, and is given the same reference numerals.

  4A is an exploded schematic cross-sectional view of the sealed battery in the dotted frame r of FIG. 3, and FIG. 4B is a schematic cross-sectional view of the sealed battery in the dotted frame r of FIG. The sealing material 40 has a recess 42 on at least one of the surfaces in contact with the lid 32 and the container 34. However, the sealing material 40 is shown in FIG. ), (B), it is preferable to have a recess 42 on the surface of the battery case 28 in contact with the lid 32 and the container 34.

  The shape of the recess 42 of the sealing material 40 is not particularly limited as long as it has a space in which the detection gas can be enclosed when the lid 32 and the container 34 are sealed. Moreover, it is preferable that the recessed part 42 is formed in the perimeter of the sealing material 40 at the point which can confirm the airtightness between the cover body 32 and the container 34 with a sufficient precision.

  The material constituting the sealing material 40 is not particularly limited as long as it has elasticity in order to increase the airtightness between the lid 32 and the container 34. Examples thereof include silicone rubber.

  In the same manner as described above, the sealed battery 3 accommodates the electrode body 26 in the container 34 in a sealed container in a detection gas atmosphere, and sandwiches the sealing material 40 between the lid body 32 and the container 34, and then caulking or the like. Produced. As shown in FIG. 4B, the recess 42 of the sealing material 40 is sealed by the lid 32 and the container 34, and is deformed by caulking. Since the sealed battery 3 is manufactured in the sealed container 10 in the detection gas atmosphere, the detection gas is sealed in the battery case 28 and the recess 42. And the pressure of the detection gas in the recessed part 42 can be raised because the recessed part 42 into which the detection gas was introduced deform | transforms by caulking.

  In this way, by increasing the pressure of the detection gas in the recess 42, the detection gas leaking from the sealed battery 3 can be detected in a short time even if the sealed container 10 is not in a reduced pressure atmosphere in the subsequent gas detection step. be able to.

<Gas detection step>
After the sealed battery 3 is manufactured, the valve 22b of the vacuum exhaust pipe 20 shown in FIG. 1 is opened, the vacuum pump 16 is operated, the detection gas in the sealed container 10 is removed, and then the valve of the vacuum exhaust pipe 20 is closed. Then, the inside of the sealed container 10 is made into a reduced pressure atmosphere, and the detection gas leaking from the inside of the sealed battery 2 is detected by the gas sensor 24. If the detection gas is not detected by the gas sensor 24, it can be determined as a good sealed battery. However, as described above, since the pressure of the detection gas in the recess 42 is increased, even if the inside of the sealed container 10 is at atmospheric pressure, gas leakage tends to occur in a poorly sealed battery. Therefore, the detection gas leaking from the inside of the sealed battery 3 can be detected in a short time. In order to detect the detection gas leaking from the inside of the sealed battery 3 at atmospheric pressure, as described above, for example, the sealed container 10 is provided with an open port (not shown) communicating with the outside air, and the vacuum pump 16 is used to seal the sealed container. After the detection gas in 10 is removed, the opening may be opened, the inside of the sealed container 10 may be returned to atmospheric pressure, and the detection gas leaking from the sealed battery 2 may be detected by the gas sensor 24.

  As described above, the hermetic inspection method for a sealed battery according to the present embodiment includes a manufacturing step for producing a sealed battery in a sealed container in a detection gas atmosphere, and after removing the detected gas in the sealed container, the atmospheric pressure By having a gas detection step for detecting a detection gas leaking from the inside of the sealed battery in the following sealed container, the hermeticity of the sealed battery can be evaluated easily and accurately in a short time. Further, in the hermetic inspection method for a sealed battery according to the present embodiment, in order to detect gas leakage of the sealed battery on at least one of the lid constituting the battery case and the surface of the sealing material in contact with the container. By using a sealed battery having a recess that encloses the detected gas, the hermeticity of the sealed battery can be evaluated more efficiently.

It is a schematic diagram for demonstrating an example of the airtight test | inspection method of the sealed battery which concerns on this embodiment. It is a schematic cross section which shows an example of a structure of the sealed battery which concerns on this embodiment. It is a schematic cross section which shows an example of the structure of the sealed battery which concerns on other embodiment of this invention. (A) is an exploded schematic cross-sectional view of the sealed battery in the dotted frame r of FIG. 3, and (b) is a schematic cross-sectional view of the sealed battery in the dotted frame r of FIG. It is a schematic diagram for demonstrating the airtight test | inspection method of a prior art example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Inspection apparatus, 2-4 sealed battery, 10 sealed container, 12 detection gas cylinder, 14 pressure gauge, 16 vacuum pump, 18 detection gas introduction pipe, 20 vacuum exhaust pipe, 22a, 22b valve, 24 gas sensor, 26 electrode body, 28 Battery Case, 30 Sealing Material, 32 Lid, 34 Container, 36a, 36b Electrode Terminal, 38a Positive Electrode Lead, 38b Negative Electrode Lead, 40 Sealing Material, 42 Recess, 44 Gas Injection Pipe, 46 High Pressure Gas Cylinder, 48 Pressure Gauge, 50 valve.

Claims (3)

A production step of producing a sealed battery in a sealed container in a detection gas atmosphere;
A gas detection step of detecting the detection gas leaking from the sealed battery in the sealed container at or below atmospheric pressure after removing the detected gas in the sealed container. Airtightness inspection method. A production step of producing a sealed battery including a battery case in which a lid and a container are sealed via a sealing material having a recess in a sealed container in a detection gas atmosphere;
A gas detection step of detecting the detection gas leaking from the inside of the battery case or the inside of the recess in the sealed container at or below atmospheric pressure after the detection gas in the sealed container is removed. Airtight inspection method for sealed batteries. A sealed battery including a battery case in which a lid and a container are sealed via a sealing material,
The sealing material has a recess in at least one of the surface that contacts the lid and the container, and detects gas leakage of the sealed battery in the recess when the lid and the container are sealed. A sealed battery characterized by enclosing a detection gas for causing the gas to enter.

Images