KR20230039006A - Leak detection device for secondary battery - Google Patents

Abstract

The present invention relates to a leak detection device and method for a secondary battery. According to an embodiment of the present invention, the leak detection device for a secondary battery comprises: a vacuum generation module generating vacuum pressure; a pressure control member formed integrally with the vacuum generation module or connected to the vacuum generation module to control the degree of vacuum of the vacuum generation module; a leak detection member including a head connected to the vacuum generation module, a vacuum nozzle connected to a liquid injection hole of a secondary battery, and a vacuum hopper having one end coupled to the head and having the other end coupled to the vacuum nozzle; and a vacuum sensor detecting changes in the vacuum pressure in the vacuum hopper when the leak detection member is connected to the secondary battery so that the inside of a can of the secondary battery is in a vacuum state. Accordingly, an expensive high-pressure vacuum pump to increase the degree of vacuum is not required, thereby reducing investment costs, maintenance costs, and process time. In addition, the structure of the leak detection device is improved, thereby detecting finer leaks than before with the same vacuum pump.

Description

Leak detection device for secondary battery and leak detection method {Leak detection device for secondary battery}

Embodiments of the present invention relate to a leak detection device and a leak detection method for a secondary battery.

A secondary battery includes an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, and a cell including an electrolyte solution impregnated in the electrode assembly.

In general, a manufacturing process of a secondary battery goes through a process of inserting an electrode assembly into a can, etc., followed by an injection process of injecting an electrolyte solution, and then sealing the can to complete the secondary battery assembly. At this time, if there is a fine hole or crack in the can, life and performance of the battery may be reduced, as well as safety accidents including fire may be caused, so a complete investigation for leak detection is essential.

As an example of leak detection, there is a method of injecting He gas to measure the amount of leakage or inserting a can into the test area to seal it and applying pressure, and then checking the amount of pressure to check whether or not there is a leak. In the former case, a separate inspection device is required, and the next inspection is possible only when residual He gas is removed after inspection, which poses a difficult process and equipment configuration and operation. In the latter case, even very minute leaks can be detected if vacuum inspection conditions are strengthened, but there is a problem in that a large number of expensive vacuum pumps are required. That is, as the inspection specification increases, the investment cost and maintenance cost increase rapidly, and the process time and installation area also increase.

The above-described information disclosed in the background art of the present invention is only for improving the understanding of the background of the present invention, and thus may include information that does not constitute prior art.

An object of the present invention is to provide a leak detection device and a leak detection method for a secondary battery capable of detecting minute leaks.

An apparatus for detecting leakage of a secondary battery according to an embodiment of the present invention includes a vacuum generating module for forming a vacuum pressure; a pressure adjusting member integrally formed with the vacuum generating module or connected to the vacuum generating module to control a degree of vacuum of the vacuum generating module; a leak detection member having a head connected to the vacuum generating module, a vacuum nozzle connected to the liquid injection hole of the secondary battery, and a vacuum hopper having one end coupled to the head and the other end coupled to the vacuum nozzle; and a vacuum sensor configured to sense a change in vacuum pressure in the vacuum hopper when the leak detection member is connected to the secondary battery and the inside of the secondary battery is in a vacuum state.

The vacuum valve may be installed on a fluid line supplying fluid to the vacuum hopper or discharging fluid from the vacuum hopper to open and close the fluid line.

When the vacuum nozzle is brought into close contact with the injection hole, the vacuum valve is opened and the vacuum generating module is turned on to apply vacuum until a preset vacuum pressure is reached for a first preset time.

When the preset vacuum pressure is reached, the vacuum valve is closed to end the application of the vacuum, and leakage of the secondary battery is detected for a second preset time.

The variation of the vacuum pressure is a variation of a difference value obtained by subtracting the vacuum start pressure from the vacuum maintenance end pressure, and when the vacuum pressure variation occurs, the control unit determines that the secondary battery is leaking.

The vacuum generating module is a vacuum ejector that generates a vacuum when pneumatic pressure is applied, and the pressure adjusting member is a pneumatic regulator.

The vacuum generating module is a vacuum pump, and the pressure adjusting member is a servo valve.

In addition, an embodiment of the present invention includes moving the secondary battery to a leak detection position; connecting a vacuum nozzle to an injection hole of the secondary battery; opening a vacuum valve and turning on a vacuum generating module to form a preset vacuum pressure; detecting a change in vacuum pressure in the vacuum hopper with a vacuum sensor when the preset vacuum pressure is reached; and determining whether the secondary battery is leaked by a control unit according to whether the vacuum pressure changes.

It is characterized in that the vacuum pressure is applied for a first set time, and the change in the vacuum pressure is detected for a second set time.

The variation of the vacuum pressure is characterized in that the variation of the difference value obtained by subtracting the vacuum starting pressure from the vacuum maintenance end pressure.

According to an embodiment of the present invention, since an expensive high-pressure vacuum pump is not required to increase the degree of vacuum, it is possible to reduce investment cost, maintenance cost, and process time.

In addition, according to an embodiment of the present invention, the number of vacuum pumps can be reduced, so the installation area can be reduced.

In addition, according to an embodiment of the present invention, the structure of the leak detection device is improved, so that a leak more minute than before can be detected using the same vacuum pump.

1 is a diagram briefly showing the configuration of a leak detection device for a secondary battery according to an embodiment of the present invention.
FIG. 2 is a perspective view schematically illustrating an installation example of the leak detection member according to FIG. 1 .

The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and the following examples may be modified in many different forms, and the scope of the present invention is as follows It is not limited to the examples. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the spirit of the invention to those skilled in the art.

In addition, in the following drawings, the thickness or size of each layer is exaggerated for convenience and clarity of explanation, and the same reference numerals refer to the same elements in the drawings. As used herein, the term "and/or" includes any one and all combinations of one or more of the listed items. In addition, the meaning of "connected" in the present specification means not only when member A and member B are directly connected, but also when member A and member B are indirectly connected by interposing member C between member A and member B. do.

Terms used in this specification are used to describe specific embodiments and are not intended to limit the present invention. As used herein, the singular form may include the plural form unless the context clearly indicates otherwise. Also, when used herein, “comprise, include” and/or “comprising, including” refers to a referenced form, number, step, operation, member, element, and/or group thereof. presence, but does not preclude the presence or addition of one or more other shapes, numbers, operations, elements, elements and/or groups.

In this specification, terms such as first and second are used to describe various members, components, regions, layers and/or portions, but these members, components, regions, layers and/or portions are limited by these terms. It is self-evident that These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first member, component, region, layer or section described in detail below may refer to a second member, component, region, layer or section without departing from the teachings of the present invention.

Space-related terms such as “beneath,” “below,” “lower,” “above,” and “upper” are associated with an element or feature shown in a drawing. It can be used for easy understanding of other elements or features. Terminology related to this space is for easy understanding of the present invention according to various process conditions or use conditions of the present invention, and is not intended to limit the present invention. For example, if an element or feature in a figure is turned over, an element or feature described as "lower" or "below" becomes "above" or "above." Accordingly, "lower" is a concept encompassing "upper" or "below".

Hereinafter, a leak detection device for a secondary battery according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram briefly showing the configuration of a leak detection device for a secondary battery according to an embodiment of the present invention. FIG. 2 is a perspective view schematically illustrating an installation example of the leak detection member according to FIG. 1 .

As shown in FIGS. 1 and 2 , the leak detection device 50 is a device that detects leakage of the secondary battery 10 . The leak detection device 50 includes a leak detection member 51 for detecting a leak, a vacuum generating module 53 for creating a vacuum state, a pressure adjusting member 54 for adjusting the pressure of the vacuum generating module 53, and , a vacuum sensor 55 for sensing vacuum pressure, and a vacuum valve 56 for opening and closing a line connected to the vacuum generating module 53. The above components are arranged on one process line and are connected with a plurality of pipes, tubes, connectors, etc. (connecting members). A separate description of the connecting member connecting them will be omitted.

Among the components of the leak detection device 50, components requiring control such as opening/closing or on-off may be controlled by a separate control unit. The control unit (controller) and/or other related devices or components according to embodiments of the present invention are implemented using any suitable hardware, firmware (eg, application specific semiconductor), software, or a suitable combination of software, firmware, and hardware. It can be. For example, various components of a control unit (controller) and/or other related devices or parts according to the present invention may be formed on one integrated circuit chip or on separate integrated circuit chips. In addition, various components of the control unit (controller) may be implemented on a flexible printed circuit film, and may be formed on a tape carrier package, a printed circuit board, or the same substrate as the control unit (controller). In addition, various components of the control unit (controller) may be processes or threads executed in one or more processors in one or more computing devices, which execute computer program instructions to perform various functions mentioned below. and can interact with other components. Computer program instructions are stored in memory that can be executed in a computing device using standard memory devices, such as, for example, random access memory. Computer program instructions may also be stored on other non-transitory computer readable media, such as, for example, a CD-ROM, flash drive, or the like. In addition, those skilled in the art related to the present invention will understand that the functions of various computing devices can be combined with each other, integrated into one computing device, or the functions of a particular computing device can be incorporated into one or more other computing devices without departing from the exemplary embodiments of the present invention. It should be recognized that it can be dispersed in the field.

For example, the control unit (controller) according to an embodiment of the present invention may include a central processing unit, a mass storage device such as a hard disk or a solid-state disk, a volatile memory device, an input device such as a keyboard or mouse, and an output device such as a monitor or printer. It can be operated on a conventional commercial computer consisting of. Hereinafter, it should be understood that the control subject exists separately even if the control subject of configurations requiring control is not separately mentioned.

The secondary battery 10 may be moved to a location where the leak detection member 51 is installed by the transfer device 30 . The leak detection member 51 is directly connected to the liquid injection hole 12 formed in the can of the secondary battery 10, and is in a vacuum state by the vacuum generating module 53 to detect leakage of the secondary battery 10. The vacuum generating module 53 generates a vacuum, and the pressure adjusting member 54 precisely controls the pressure supplied to the vacuum generating module 53 . Vacuum sensor 55 measures the vacuum pressure, and vacuum valve 56 opens and closes the fluid line for vacuum or vacuum break (vacuum release).

The main configuration of the leak detection device will be described in more detail as follows.

The leak detecting member 51 adheres to the liquid injection hole 12 formed in the can of the secondary battery 10 to create a vacuum inside the secondary battery 10 and detects leakage using a pressure difference between the fluids. To this end, the leak detection member 51 includes a vacuum hopper 511, a vacuum nozzle 513 coupled to the lower end of the vacuum hopper 511, and a head 515 coupled to the upper end of the vacuum hopper 511. can do.

The vacuum hopper 511 has a cylindrical pipe shape, and the inside is hollow so that the upper and lower ends communicate with each other. The vacuum hopper 511 serves as a passage through which fluid such as air moves, and serves to support the vacuum nozzle 513 and the head 515 . The vacuum hopper 511 is formed to have a minimum volume capable of maintaining a vacuum while being coupled with the vacuum nozzle 513 and the head 515 (the shape can be changed from the above-described cylindrical pipe shape to another shape) . Accordingly, the leak detection ability is enhanced and it can be commonly used for inspecting secondary batteries 10 of various sizes.

The upper end of the vacuum nozzle 513 is coupled to the vacuum hopper 511 and the lower end adheres to the injection hole 12 of the secondary battery 10 . The vacuum nozzle 513 may have a conical shape whose diameter gradually decreases from the top to the bottom. However, the lower end of the vacuum nozzle 513 has a diameter sufficient to cover the injection hole 12 of the secondary battery 10 . In addition, the vacuum nozzle 513 should be able to maintain a state in close contact with the injection hole 12 at the lower end. Therefore, the vacuum nozzle 513 has enough rigidity to maintain its shape, but when pressed by an external force, a predetermined elastic deformation occurs to cover the injection hole 12 and have elasticity to adhere to the upper surface of the can. . For example, the vacuum nozzle 513 may be made of a material such as soft plastic, rigid rubber, or silicon. The stiffness or elasticity of the material of the vacuum nozzle 513 may be determined in advance within a range in which the lower end of the vacuum nozzle 513 may come into close contact with the can when the second driving unit 13, which will be described later, descends.

The head 515 is coupled to an upper end of the vacuum hopper 511 and may be connected to a line through which fluid moves by having a connector 515a. The vacuum sensor 55 and the vacuum valve 56 may be directly connected to the head 515, and the vacuum sensor 55 and the vacuum valve 56 are adjacent to the head 515 on the fluid line to which the connector 515a is connected. may be installed separately. The leak detection member 51 is connected to the vacuum generating module 53 through the head 515 and the vacuum valve 56.

The vacuum generating module 53 is for making the vacuum hopper 511 of the leak sensing member 51 into a vacuum state. The pressure adjusting member 54 may be installed adjacent to the vacuum valve 56 and serves to automatically adjust the vacuum state of the vacuum generating module 53 according to a preset vacuum level recipe. The vacuum generating module 53 may include a vacuum pump capable of generating low or high pressure, a vacuum ejector, and the like. Illustratively, when the preset vacuum pressure is 90 ± 2 kPa, it corresponds to the low pressure range, so the vacuum generating module 53 may be configured as a vacuum ejector. When the vacuum generating module 53 is composed of a vacuum ejector, vacuum control of the vacuum ejector may be performed by a pneumatic regulator (electronic regulator) as the pressure adjusting member 54 . Also, illustratively, when the preset vacuum pressure exceeds 90 kPa, the vacuum generating module 53 may be configured as a vacuum pump. When the vacuum generating module 53 is configured as a vacuum pump, the vacuum control of the vacuum pump may be performed by a servo valve as the pressure adjusting member 54 .

When a vacuum is generated by the vacuum generating module 53, the fluid inside the secondary battery 10 passes through the leak detecting member 51 connected to the secondary battery 10 through the leak detecting member 51 and the vacuum generating module 53. is exhausted through the air, and the inside of the secondary battery 10 becomes a vacuum state.

When the vacuum pressure inside the secondary battery 10 measured by the vacuum sensor 55 reaches a preset vacuum pressure, the vacuum valve 56 is closed to maintain the vacuum state, and then the secondary battery ( 10) can measure the internal vacuum fluctuation pressure. Due to the generation of vacuum, a pressure difference between the vacuum hopper 511 and the secondary battery 10 is generated. Therefore, if the vacuum start pressure is subtracted from the vacuum maintenance end pressure (vacuum pressure when the vacuum valve is closed after reaching the set vacuum pressure), the vacuum fluctuation pressure, which is the extent to which the vacuum degree fluctuates, can be found. If the vacuum fluctuation pressure is kept constant or within the allowable pressure deviation range, it can be seen that there is no leakage of the secondary battery 10, and if the vacuum fluctuation pressure over time increases or exceeds the allowable pressure deviation range, the secondary battery 10 can It can be determined that there is a leak in (this will be described later).

The aforementioned vacuum valve 56 may be installed on a fluid line for withdrawing or supplying fluid from the vacuum hopper 511 as needed. In addition, an air filter for filtering foreign substances may be additionally installed on the fluid line through which the fluid flows into the leak detection member 51, if necessary.

The vacuum valve 56 serves to open and close the fluid line, and when the vacuum valve 56 is installed, it is possible to know whether there is a micro-leak in a closed state of the fluid line.

Hereinafter, the leak detection method will be described in detail.

In the secondary battery 10 exemplarily described in the present invention, an electrode assembly and an electrolyte are accommodated in an aluminum can and sealed. When the secondary battery 10 is sealed in a can, all cans are thoroughly inspected to ensure that internal materials such as electrolyte do not leak, and leaks due to micro-holes are checked. To this end, the secondary battery 10 may be moved to a leak test position and a liquid injection position by the transfer device 30 .

The transfer device 30 includes a battery transfer unit 11 that moves while the secondary battery 10 is mounted, a first driving unit 12 that moves the leak detection member 51 forward or backward, and the leak detection member 51. It may include a second driving unit 13 that raises or lowers. The battery transfer unit 11 may be configured by borrowing a known technique such as a conveyor belt or a carrier. A plurality of clamps 111 may be installed in the battery transfer unit 11 to prevent the secondary battery 10 from shaking or falling during transportation and to guide the alignment position of the secondary battery 10 .

One secondary battery 10 is moved to a leak detection position by the first driving unit 12 and transferred to a separate liquid injection device after leak detection. A plurality of leak detection members 51 may be disposed on one side of the transfer device 30 . Accordingly, leak detection may be performed by inspecting the plurality of secondary batteries 10 at once. Alternatively, the system may be configured so that the leak detection member 51, not the secondary battery 10, moves.

The leak detection location is a location where the leak detection member 51 is installed. As the leak detection member 51 is lowered by the second driving unit 13 at the leak detection position, the vacuum nozzle 513 may be closely attached to the injection hole 12 of the can of the secondary battery 10 (or the secondary battery 10 ) may be configured to rise toward the leak detection member 51). In this state, a vacuum is generated by the vacuum generating module 53, and the inside of the leak detection member 51 and the secondary battery 10 connected thereto become in a vacuum state.

The vacuum generation and leak detection process will be described in more detail as follows.

When the leak detection member 51 descends to the secondary battery 10 and the vacuum nozzle 513 adheres to the liquid injection hole 12, the vacuum valve 56 is opened and the vacuum generating module 53 is turned on. A vacuum may be applied. Thereafter, a vacuum pressure P may be formed for a leak check for a first set time. Illustratively, in order to form a more effective vacuum pressure, a vacuum may be formed for half of the first set time and the vacuum may be stabilized for the other half. In some examples, the first set time may be 10 seconds. In this case, vacuum pressure may be formed for 5 seconds, and vacuum stabilization may be performed for the remaining 5 seconds.

When the formation of the vacuum pressure is completed, the vacuum valve 56 is closed to end the application of the vacuum, and leak detection may be performed for a second set time. At this time, the vacuum generating module 53 may be turned off or maintained in an on state. In some examples, the second set time may range from 20 seconds to 60 seconds. Leak detection can be performed by measuring whether or not there is a change in vacuum pressure (hereinafter, defined as a vacuum fluctuation pressure (ΔP)), that is, a reduced pressure. The meaning that the vacuum fluctuation pressure ΔP is generated means that the difference value (A) obtained by subtracting the vacuum start pressure from the vacuum maintenance end pressure after the vacuum valve 56 is closed after the vacuum pressure is formed fluctuates (here, the vacuum maintenance ends). means a state in which the vacuum valve is closed while maintaining the state in which the vacuum pressure is formed up to the set target, not in the state in which the vacuum is subtracted). If there is a leak, the vacuum pressure is reduced from the vacuum maintenance end pressure, and the difference value (A) is changed, so that the vacuum fluctuation pressure (ΔP) is generated. Conversely, if there is no leak, since the end pressure of maintaining the vacuum does not change, the difference value A does not fluctuate and the vacuum fluctuation pressure ΔP does not occur. In addition, even if the secondary battery 10 to be inspected is different, if the size and standard are the same, when there is a leak of the same size, the vacuum fluctuation pressure (ΔP) appears to be the same size. When the leak detection is completed, the vacuum valve 56 is opened again to break the vacuum and the secondary battery 10 is moved to the liquid injection position.

Illustratively, in this embodiment, the range of the reference vacuum pressure for detecting a 50 μm-sized leak (hole or crack) may be in the range of about 8 to 90 kPa. However, the range of the reference vacuum pressure may vary as needed, and leak detection is possible if the difference between the end pressure of maintaining the vacuum and the starting pressure of the vacuum is at least two times greater. If the reference vacuum pressure is too small, the vacuum fluctuation pressure ΔP may not be generated or the vacuum fluctuation pressure ΔP may not be detected. Conversely, if the reference vacuum pressure is too high, expensive high-pressure equipment is required to generate vacuum pressure, and as the number of inspection targets increases, the number of high-pressure pumps also increases, resulting in increased facility costs. However, according to the present embodiment, it is possible to configure equipment capable of inspecting minute leaks without expensive high-pressure equipment.

What has been described above is only one embodiment for carrying out the present invention, and the present invention is not limited to the above-described embodiments, and as claimed in the following claims, the present invention without departing from the gist of the present invention Anyone skilled in the art will say that the technical spirit of the present invention exists to the extent that various changes can be made.

50: leak detection device 51: leak detection member
511: vacuum hopper 513: vacuum nozzle
515: head 53: vacuum generating module
54: pressure regulating member 55: vacuum sensor
56: vacuum valve 57: sub adjusting member
58: air filter 59: solenoid valve

Claims (10)

a vacuum generating module that forms a vacuum pressure;
a pressure adjusting member integrally formed with the vacuum generating module or connected to the vacuum generating module to control a degree of vacuum of the vacuum generating module;
a leak detection member having a head connected to the vacuum generating module, a vacuum nozzle connected to the liquid injection hole of the secondary battery, and a vacuum hopper having one end coupled to the head and the other end coupled to the vacuum nozzle; and
A leak detection device for a secondary battery comprising a vacuum sensor for detecting a change in vacuum pressure in the vacuum hopper when the leak detection member is connected to the secondary battery and the inside of the can of the secondary battery is in a vacuum state. According to claim 1,
The leak detection device for a secondary battery further comprising a vacuum valve installed on a fluid line supplying fluid to the vacuum hopper or discharging fluid from the vacuum hopper to open and close the fluid line. According to claim 2,
When the vacuum nozzle is in close contact with the injection hole, the vacuum valve is opened and the vacuum generating module is turned on to apply a vacuum until a preset vacuum pressure is reached for a first set time, leak detection of a secondary battery Device. According to claim 3,
When the preset vacuum pressure is reached, the vacuum valve is closed to terminate the application of the vacuum, and the leak detection of the secondary battery is performed for a second set time. According to claim 4,
The change in vacuum pressure is a change in the difference value obtained by subtracting the vacuum start pressure from the vacuum maintenance end pressure, and when the change in vacuum pressure occurs, the control unit determines that the secondary battery is leaking. According to claim 1,
The vacuum generating module is a vacuum ejector that generates a vacuum when pneumatic pressure is applied, and the pressure adjusting member is a pneumatic regulator. According to claim 1,
The vacuum generating module is a vacuum pump, and the pressure adjusting member is a servo valve. moving the secondary battery to a leak detection position;
connecting a vacuum nozzle to an injection hole of the secondary battery;
opening a vacuum valve and turning on a vacuum generating module to form a preset vacuum pressure;
detecting a change in vacuum pressure in the vacuum hopper with a vacuum sensor when the preset vacuum pressure is reached; and
A method for detecting leakage of a secondary battery comprising the step of determining, by a control unit, a leak of the secondary battery according to whether a change in the vacuum pressure occurs. According to claim 8,
Wherein the vacuum pressure is applied for a first set time, and the change in the vacuum pressure is sensed for a second set time. According to claim 8,
The change in the vacuum pressure is a change in the difference value obtained by subtracting the vacuum start pressure from the vacuum maintenance end pressure, the leak detection method of the secondary battery.

Images