KR20160143038A - Leak inspection apparatus and method of secondary battery - Google Patents

Abstract

The present invention provides a leak inspection apparatus and a method for a secondary battery to discriminate a leak from a secondary battery. According to the present invention, the leak inspection apparatus comprises: a chamber for accommodating a secondary battery; a vacuum pump for decompressing the inside of the chamber in which the secondary battery is accommodated; and a swelling discrimination unit for discriminating swelling of the case of the secondary battery accommodated in the chamber.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a leak inspection apparatus and method for a secondary battery,

Embodiments of the present invention relate to an apparatus and method for checking leakage of a secondary battery.

Generally, a secondary battery is a device that converts external electrical energy into a form of chemical energy and stores it, and then generates electricity when necessary. Unlike a primary battery, the secondary battery can be charged and discharged many times. The secondary battery includes, for example, a lead-acid battery, a nickel-cadmium battery (NiCd), a nickel metal hydride battery (NiMH), a lithium ion battery (Li-ion), and a lithium ion polymer battery (Li-ion polymer battery).

In addition, such a secondary battery is manufactured in various shapes and can be roughly divided into a cylindrical shape, a prismatic shape, and a pouch shape.

First, a pouch-type secondary battery is formed by, for example, an electrode assembly composed of two electrodes for indicating an anode and a cathode, and a separation membrane for preventing a short circuit between the two electrodes, together with an electrolyte, as a flexible and flexible film And can have a high energy density because it is made of a pouch packaging material that is significantly lighter than an aluminum case and is a flexible film. However, in the case of a pouch type secondary battery, pinholes or cracks, which are hard to observe in the naked eye, are formed in the pouches as compared with a case in which the pouches are made of a metal material, May occur, which may deteriorate the safety of the battery.

On the other hand, the cylindrical secondary battery may include, for example, a cylindrical case for housing the electrode assembly together with the electrolyte, and a cap assembly sealingly coupled to the open end of the cylindrical case by a gasket. However, in the process of assembling the cap assembly and the case through the gasket, there is a high possibility that a gap is generated between the gasket and the cap assembly or between the gasket and the case.

The prismatic type secondary battery includes a case for defining a rectangular parallelepiped having an open surface as a whole and accommodating therein an electrode assembly and an electrolytic solution together, and a case sealingly coupled to the opened surface of the case through a gasket There is a problem that the gap between the gasket and the cap plate or between the gasket and the case is likely to be generated so that the airtightness of the battery is lowered, similarly to the cylindrical secondary battery.

In the case of a cylindrical secondary battery or a prismatic secondary battery, an electrolyte injection port may be provided in the cap plate or the cap assembly. The electrolyte injection port may be sealed or sealed after the electrolyte is injected. However, Or may be incompletely formed.

Accordingly, there is a need for an apparatus and method that can determine whether a leaky secondary battery is defective by checking whether the airtightness formed in the secondary battery is maintained.

Korean Patent Publication No. 10-2012-0115835 (Oct. 19, 2012) Korean Patent Publication No. 10-2013-0027151 (Feb. Korean Patent Publication No. 10-2013-0054841 (Feb. Korean Patent Laid-Open Publication No. 10-2015-0009876 (2015. 01. 27.)

Embodiments of the present invention are to provide an apparatus and method for detecting leakage of a secondary battery for discriminating whether or not a secondary battery is leaked.

However, the technical problem to be solved by the present invention is not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a secondary battery including: a chamber for accommodating a secondary battery; A vacuum pump for decompressing the interior of the chamber accommodating the secondary battery; And a swelling discriminating device for discriminating whether swelling occurs in the case of the secondary battery accommodated in the chamber.

And an image acquiring device for acquiring an image of the secondary battery accommodated in the chamber, wherein the image acquiring device includes: a first image of the secondary battery housed in the chamber before decompressing the interior of the chamber; The second image of the secondary battery accommodated in the chamber after the inside of the chamber is decompressed by the vacuum pump.

And an image processing device for comparing the first image and the second image of the secondary battery with each other to determine that the case of the secondary battery is swelled when the size of the secondary battery is increased have.

The size of the secondary battery may be the thickness of the secondary battery.

The chamber may be provided with an observation window through which the interior of the chamber can be viewed, and the image acquisition device may be disposed outside the chamber to acquire an image of the secondary battery through the observation window.

The leakage inspection apparatus of the secondary battery further includes a tray for holding the secondary battery accommodated in the chamber so as to be lifted up. When the casing of the secondary battery is swollen, And a sensing unit for sensing the swelled case.

The sensing unit may be a pressure sensor disposed on the tray so as to be pushed by the swelled case.

The secondary battery may be a pouch-type secondary battery in which the case is made of a film.

The vacuum pump is capable of reducing the internal pressure of the chamber to a target pressure which is lower than atmospheric pressure and which is equal to or higher than a degassing pressure of the secondary battery.

The degassing pressure may be greater than 0 and less than 20 torr, and the target pressure may be between 20 and 50 torr.

 The target pressure may be maintained for at least 30 seconds.

According to another aspect of the present invention, there is provided a method of manufacturing a secondary battery, comprising: disposing a secondary battery in a chamber; Depressurizing the interior of the chamber; And a step of observing or sensing whether or not swelling occurs in the case of the secondary battery so as to determine whether the secondary battery is leaking.

The depressurizing step may depressurize the interior of the chamber to a target pressure that is less than atmospheric pressure and that is equal to or higher than a degassing pressure of the secondary battery.

The leakage inspection method of the secondary battery may maintain the target pressure for a predetermined time.

Wherein the secondary battery is a pouch-type secondary battery in which the casing is made of a film, and the leakage inspection method of the secondary battery is characterized in that when there is no swelling in the case of the secondary battery, .

According to another aspect of the present invention, there is provided a method of manufacturing a secondary battery, comprising: disposing a secondary battery in a chamber; Depressurizing the interior of the chamber; And observing whether or not wrinkles have occurred in the film constituting the case of the secondary battery in order to determine whether or not the secondary battery is leaked.

The depressurizing step may depressurize the interior of the chamber to a target pressure that is less than atmospheric pressure and that is equal to or higher than a degassing pressure of the secondary battery.

According to another aspect of the present invention, there is provided a method of manufacturing a secondary battery, comprising: providing a bubble-forming liquid on at least a surface portion of a secondary battery; Disposing the secondary battery in a chamber; Depressurizing the chamber; And observing whether a bubble is generated in the secondary battery to determine whether or not there is a leak in the secondary battery.

The bubbling liquid may be a soap solution.

1 is a diagram showing a schematic configuration of a leakage inspection apparatus for a secondary battery according to an embodiment of the present invention,
2 is a schematic side view of a chamber of a leakage inspection apparatus for a secondary battery according to an embodiment of the present invention,
3 is a diagram schematically showing a configuration of a swell discrimination apparatus for a leak test apparatus for a secondary battery according to another embodiment of the present invention,
4 is a flowchart showing a leakage inspection method of a secondary battery according to another embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. However, this is merely an example and the present invention is not limited thereto.

In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intention or custom of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

The technical idea of the present invention is determined by the claims, and the following embodiments are merely a means for effectively explaining the technical idea of the present invention to a person having ordinary skill in the art to which the present invention belongs.

Referring to FIG. 1, a diagram illustrating a schematic configuration of a leakage testing apparatus for a secondary battery according to an embodiment of the present invention is shown. Referring to FIG. 2, A schematic side view of a chamber of the apparatus is shown.

1 and 2, a leakage inspection apparatus 100 for a secondary battery according to an embodiment of the present invention includes a secondary battery 1, for example, a pouch type secondary battery 1 A chamber (10) for receiving the gas; A vacuum pump 50 for reducing the interior of the chamber 10 for accommodating the secondary battery 1; For example, the image acquiring device 30 or the sensing unit 30a (or the outer wall surface) of the rechargeable battery 1 accommodated in the chamber 10, (See FIG. 3). Here, the vacuum pump 50 is capable of reducing the pressure inside the chamber 10 to a target pressure which is lower than the atmospheric pressure and which is equal to or higher than the degassing pressure of the secondary battery 1. That is, when there is a leak in the case of the secondary battery 1, the pressure in the secondary battery 1 is higher than the digging pressure due to the inflow of outside air, so even if the target pressure is equal to or greater than the digging pressure, It is possible to generate swelling of the liquid.

In the manufacturing process of the pouch type secondary battery 1, for example, the electrode assembly (not shown), which is a power generation element, is disposed in a case, for example, a pouch made of a film, and an opening formed in a part of the pouch The secondary battery 1 is charged into the electrode tab 2 of the secondary battery 1 for charging for a predetermined period of time and then the generated gas is removed. A degassing pressure may be formed in the secondary battery 1 by applying a vacuum pressure in the chamber to remove the gas contained in the electrolyte and sealing the opening portion of the pouch inside the vacuum chamber after the gas is removed.

According to the leakage inspection apparatus of the secondary battery 1 as described above, when a pin hole of, for example, 0.25 mm is generated in the secondary battery 1, the pin hole can not be visually recognized and the secondary battery 1 When the secondary battery 1 is disposed in the chamber 10 and the inside of the chamber 10 is depressurized, the gas introduced into the secondary battery 1 through the pin hole causes the leakage of the secondary battery 1, The case of the secondary battery 1 is swollen, so that it can be easily discriminated that the secondary battery 1 is leaked.

The chamber 10 is used to hermetically accommodate the secondary battery 1 and does not necessarily have to accommodate the entire secondary battery 1. For example, Or may be accommodated in the chamber 10 so as to be exposed to the outside of the chamber 10 or only one side of the secondary battery 1 may be placed under the reduced pressure of the chamber 10. The interior of the chamber 10 for accommodating the secondary battery 1 can be evacuated by the vacuum pump 50 and depressurized and can be blocked or blocked by a door (not shown). In addition, the inside of the chamber 10 may be released from the vacuum state by introducing air into the inside, for example, by opening of a vacuum release valve (not shown).

The secondary battery 1 accommodated in the chamber 10 can be brought into the chamber 10 in a state where it is disposed in the tray 20 as shown in Fig. 1, for example, (Arrow A). The tray 20 may include a support 21 provided with an insertion groove 21 into which a lower portion thereof can be inserted so that the secondary battery 1 can be raised, for example, as shown in Fig. 1 and 2, one secondary battery 1 is shown, but a plurality of, for example, 16 or 32 cells are arranged to be simultaneously brought into or out of the chamber 10 It may be exported.

In this embodiment, the secondary battery 1 is disposed on the tray 20 in a standing state and is moved to the inside and the outside of the chamber 10. However, the present invention is not limited to this, For example, a holder (or a stationary tray; not shown) may be provided to be fixed inside the chamber 10. [

As described above, when the interior of the chamber 10 is depressurized, the secondary battery 1 is placed on the tray 20 or the stand so that the side surface of the secondary battery 1 is pressed down by its own weight to minimize the force So that swelling of the case of the secondary battery 1 can be smoothly performed, and it is also advantageous to simultaneously work a plurality of secondary batteries 1.

In addition, the two tabs 2 of the secondary battery 1 can be extended on different sides, not on the same side of the secondary battery 1, as shown in the figure. Even in this case, The battery 1 may be disposed so as to stand on the tray 20 or the cradle so that one side of the battery 1 is directed downward.

A vacuum pump 50 for reducing the pressure inside the chamber 10 is connected to the inside of the chamber 10 to depressurize the inside of the chamber 10 to a target pressure set by the operator and further, Can maintain the target pressure for a predetermined time. For example, the vacuum pump 50 reduces the pressure in the chamber 10 from about 760 torr to about 20 to 50 torr at a vacuum rate of about 30 to 35 torr / sec, for example, Swelling may be caused to occur in the case of the secondary battery 1 having a pinhole size of 20 torr or less, for example, about 10 torr, for example, about 0.25 mm in size. In addition, by maintaining the target pressure, for example, for at least 30 seconds, it is possible to contribute to swelling of the case of the secondary battery 1, or to further increase the swelling.

Alternatively, the valve 52 may be provided on the exhaust pipe 51 connecting the chamber 10 and the vacuum pump 50, and the inside of the chamber 10 may be evacuated to a predetermined target pressure by the vacuum pump 50 The back valve 52 may be closed so that the interior of the chamber 10 is maintained at the target pressure for a predetermined time.

An image acquiring device 30 for acquiring an image of the secondary battery 1 accommodated in the chamber 10 is provided in the chamber 10 so as to discriminate whether or not the secondary battery 1 accommodated in the chamber 10 is swollen, 10, respectively. In this case, on one side of the chamber 10, there can be provided an observation window 15 through which the inside can be seen, as shown in FIG. 2, The thickness of the secondary battery 1 can be placed in the chamber 10 so that it can be seen from the outside.

The image acquiring device 30 acquires an image of the external appearance of the secondary battery 1 disposed inside the chamber 10 at least before acquiring the inside of the chamber 10 and the chamber 10 (Second image) during the depressurization to the target pressure or after the target pressure is completely reached.

The first image and the second image acquired by the image acquiring device 30 are compared with each other in the image processing device 31 so that the appearance of the secondary battery 1 after decompression, It is possible to determine whether the secondary battery 1 has undergone swelling or not, and if the external dimension, for example, the thickness, has increased, the image processing apparatus 31 determines that swelling has occurred in the secondary battery 1, Can be displayed on the display 32 as being defective due to leakage.

The image acquiring device 30 provided outside the chamber 10 acquires the image of the side surface of the secondary battery 1 through the observation window 15 so that the swelling phenomenon of the secondary battery 1 Can be effectively discriminated. That is, when swelling occurs in the secondary battery 1, the increase in thickness is most prominent in the outer dimensions of the secondary battery 1, which is most effective for swelling discrimination.

Referring to FIG. 3, there is shown a schematic configuration of a swell discrimination device of a leakage inspection apparatus 100 for a secondary battery according to another embodiment of the present invention.

3, the swell ring discriminating apparatus according to another embodiment is arranged, for example, on a tray 20 (or a cradle) so that the case of the secondary battery 1 is swellable as indicated by a dotted line, The sensing unit 30a that senses that the casing of the secondary battery 1 is being swollen and the signal of the sensing unit 30a by wire or wireless, And an indicator 33 for informing the worker of the occurrence of swelling of the workpiece. Here, the sensing portion 30a may include a pressure sensor that is pressed into the case of the swelled secondary battery 1 when the secondary battery 1 is swelled, or a displacement measuring device for measuring the displacement of the case have.

As described above, when the plurality of secondary batteries 1 are disposed on the tray 20 (or the cradle), each of the plurality of sensing portions 30a is arranged to correspond to each of the secondary batteries 1, It is possible to know which battery 1 of the secondary battery 1 is leaking.

On the other hand, after the presence or absence of swelling of the secondary battery 1 is determined through the depressurization of the inside of the chamber 10 as described above, the secondary battery 1 carried out of the chamber 10 is, for example, In the case of a battery, it can be determined whether or not the film constituting the case or the pouch is wrinkled, for example, by visually observing whether or not the secondary battery 1 is leaked. That is, the relationship between the target pressure and the size of the pinhole is not sufficient to cause the secondary battery 1 to swell while the inside of the chamber 10 is depressurized or while the target pressure is maintained after the depressurization. However, It is possible to discriminate the leakage of the secondary battery 1 through whether or not the surface of the case of the secondary battery 1 is wrinkled.

In the apparatus and method for inspecting a leak of a secondary battery according to an embodiment of the present invention, the secondary battery 1 is a pouch-type secondary battery in which the case is a film. However, the present invention is not limited thereto, A cylindrical secondary battery, or the like, and a secondary battery having a case in which an electrode assembly and an electrolyte are hermetically sealed to prevent electrolyte leakage can be applied.

Referring to FIG. 4, there is shown a flowchart illustrating a method of checking a leak of a secondary battery according to another embodiment of the present invention.

The leakage inspection method for a secondary battery according to another embodiment of the present invention is a method for inspecting a leakage of a secondary battery, for example, a cylindrical secondary battery, at least a part of the surface thereof with a liquid such as a soap solution, (S2) of supplying a bubble-forming liquid to at least a portion of the surface of the chamber (S2), and depressurizing the chamber (S3) .

Here, the step S2 of arranging the secondary battery in the chamber does not require that the chamber necessarily accommodate the entire secondary battery. For example, it is possible to expose the tab of the secondary battery to the outside of the chamber, At least a part of the secondary battery may be accommodated in an airtight state.

Further, in the case of the present embodiment, the target pressure to be depressurized in the step S3 of depressurizing the chamber may be equal to or lower than the detaching pressure of the secondary battery. As the target pressure is lower, a pressure lower than the internal pressure of the secondary battery is formed in the chamber, so that the gas inside the secondary battery can be discharged well through the leak region. In addition, the arrival velocity of the target pressure may be a predetermined exhaust velocity so that the bubble formation can be made smoothly, and may be maintained for a predetermined time after the target pressure is reached.

Further, the bubbling liquid used here can be produced so as to have a viscosity or a surface tension which is not easily removed from the surface of the secondary battery, even when the chamber is depressurized or the target pressure is reached.

According to such a method, if the produced secondary battery has a minute gap between a leak portion, for example, a pin hole, or a connection portion between the cap plate and the case, gas is introduced into the secondary battery through the leak portion Accordingly, when the chamber accommodating the secondary battery is decompressed, the gas in the secondary battery is discharged through the leaking portion of the secondary battery, so that the bubble forming liquid provided on the surface of the secondary battery can form bubbles, It is possible to judge whether or not there is a leak. At this time, for example, an observation window may be provided in the chamber, and the occurrence of bubbles can be confirmed, for example, through an image acquisition device provided outside or with the naked eye.

In addition, the secondary battery having undergone the depressurization step as described above has a cleaning step for removing the bubble forming liquid provided on the surface of the secondary battery, and a cleaning step for cleaning the secondary battery and cleaning the liquid remaining on the surface, for example, It may be further subjected to a drying step for drying with air.

While the present invention has been described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various other changes and modifications may be made without departing from the spirit and scope of the present invention as defined by the appended claims. It will be apparent to those of ordinary skill in the art.

It will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

Accordingly, the technical scope and scope of the present invention should not be limited to the embodiments described, but fall within the scope and spirit of the following claims.

1: secondary battery
2: Tab
10: chamber
15: Observation window
20: Tray
21: Support
22: insertion groove
30: Image acquisition device
30a:
31: Image processing device
32: Display
50: Vacuum pump
51: exhaust pipe
52: Valve

Claims (19)

A chamber for accommodating the secondary battery;
A vacuum pump for decompressing the interior of the chamber accommodating the secondary battery; And
And a swelling discriminating device for discriminating whether swelling occurs in the case of the secondary battery accommodated in the chamber.
The method according to claim 1,
The swelling discriminator comprises:
And an image acquisition device for acquiring an image of the secondary battery accommodated in the chamber,
The image capturing apparatus includes a first image of the secondary battery accommodated in the chamber before the interior of the chamber is decompressed and a second image of the secondary battery accommodated in the chamber after the interior of the chamber is decompressed by the vacuum pump And acquires a second image.
The method of claim 2,
The swelling discriminator comprises:
Further comprising an image processing device for comparing the first image and the second image of the secondary battery with each other to determine that the case of the secondary battery is swelled when the size of the secondary battery is increased, A leakage inspection device for a secondary battery.
The method of claim 3,
And the size of the secondary battery is the thickness of the secondary battery.
The method of claim 2,
Wherein the chamber is provided with an observation window through which the interior of the chamber can be viewed,
Wherein the image acquiring device is disposed outside the chamber and acquires an image of the secondary battery through the observation window.
The method according to claim 1,
The leakage inspection device of the secondary battery includes:
Further comprising a tray for holding the secondary battery accommodated in the chamber so as to stand up,
The swelling discriminator comprises:
And a sensing unit for sensing the swelled case of the secondary battery when the case of the secondary battery is swelled.
The method of claim 6,
Wherein the sensing unit is a pressure sensor disposed on the tray so as to be pushed by the swelled case.
The method according to claim 1,
Wherein the secondary battery is a pouch type secondary battery in which the case is made of a film.
The method of claim 8,
Wherein the vacuum pump decompresses the interior of the chamber at a target pressure that is lower than an atmospheric pressure and is equal to or higher than a degassing pressure of the secondary battery.
The method of claim 9,
Wherein the degassing pressure is in the range of more than 0 to 20 torr and the target pressure is in the range of 20 to 50 torr.
The method of claim 9,
Wherein the target pressure is maintained for at least 30 seconds.
Disposing a secondary battery inside the chamber;
Depressurizing the interior of the chamber; And
And observing or sensing whether swelling occurs in the case of the secondary battery to determine whether the secondary battery is leaking.
The method of claim 12,
Wherein the decompressing step comprises:
And the pressure inside the chamber is reduced to a target pressure which is lower than atmospheric pressure and which is equal to or higher than a degassing pressure of the secondary battery.
14. The method of claim 13,
The leakage inspection method of the secondary battery includes:
Wherein the target pressure is maintained for a predetermined period of time.
The method of claim 12,
Wherein the secondary battery is a pouch type secondary battery in which the case is made of a film,
The leakage inspection method of the secondary battery includes:
And observing whether wrinkles have occurred in the film of the secondary battery when swelling is not present in the case of the secondary battery.
Disposing a secondary battery inside the chamber;
Depressurizing the interior of the chamber; And
And a step of observing whether or not wrinkles have occurred in the film constituting the case of the secondary battery in order to determine whether or not the secondary battery is leaked.
18. The method of claim 16,
Wherein the decompressing step comprises:
And the pressure inside the chamber is reduced to a target pressure which is lower than atmospheric pressure and which is equal to or higher than a degassing pressure of the secondary battery.
Providing a bubble forming liquid to at least a portion of the surface of the secondary battery;
Disposing the secondary battery in a chamber;
Depressurizing the chamber; And
And observing whether or not bubbles are generated in the secondary battery to determine whether or not the secondary battery is leaked.
19. The method of claim 18,
Wherein the bubble forming liquid is a soapy water solution.

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