KR20230075796A - Pressure short testing device for secondary battery - Google Patents

Abstract

The present invention relates to an apparatus for inspecting a voltage short circuit of a secondary battery, wherein the inspection apparatus includes a pressure member for pressing a body of a battery cell and a detection unit for measuring current, voltage, and resistance of the battery, wherein the pressure member comprises a battery cell A buffer pad is provided on the pressing surface in contact with the separator, and the buffer pad introduces a taper pressing part to the edge of the battery cell where damage such as tearing, folding, puncture, etc. of the separator mainly occurs. It has the advantage of being able to detect defects with high reliability under low pressurization conditions.

Description

Pressurized short circuit test device for secondary battery {PRESSURE SHORT TESTING DEVICE FOR SECONDARY BATTERY}

The present invention relates to an apparatus for checking a voltage short circuit for a secondary battery.

Lithium secondary batteries, which are attracting attention as the main energy source of the next generation, can be classified according to the structure of the electrode assembly. Type) Electrode assembly, a stacked (stacked) electrode assembly in which a plurality of anodes and cathodes cut in units of a predetermined size are sequentially stacked with a separator interposed therebetween, three electrodes stacked with two separators interposed therebetween A stack-folding type electrode assembly having a structure in which unit cells such as a bi-cell or a mono-cell in which two electrodes are stacked with one separator interposed therebetween are wound with a long separator sheet can be heard

A secondary battery is manufactured by injecting an electrolyte, which is a liquid electrolyte, while the electrode assembly is housed in a battery container, and sealing the battery container. The manufactured secondary battery may have various defects due to various causes during the assembly process, manufacturing process, or use. can Among them, a phenomenon in which a battery that has been manufactured exhibits a voltage drop behavior higher than the self-discharge rate is called low voltage.

Such a low-voltage defect often occurs during assembly of a secondary battery. Types of assembly defects that cause low voltage include separator damage, such as tearing of the separator, folding of the separator, and puncture of the separator, as shown in FIG. 1 . Such damage to the separator mainly occurs at the four corners of the cell body during the battery manufacturing process.

Although the above defects can cause an internal short circuit, that is, a short circuit in which the positive electrode and the negative electrode are in contact, they are not currently in contact due to the thickness of the separator, but a short circuit can occur at any time. It is necessary to sort out the bad.

Defects in the assembly process are generally detected through vision inspection, and defects in the battery cell are determined. However, in the case of stack-folding type battery cells, folding Assembly defects that occur during the process have a problem in that it is difficult to sort out defects through vision inspection because defects occur inside the folding cell.

Therefore, using a conventional jig having an elastic pad on one side, positioning the electrode assembly on the base plate, pressing the upper surface of the electrode assembly with the jig, and then measuring the leakage current generated from the battery cell to identify defects. method is being applied.

However, since it is difficult to physically induce an internal short circuit between the positive electrode and the negative electrode provided in the battery cell, there is a limitation in that high pressure must be applied to the battery cell. In particular, when the area of the defective part is remarkably small or the size of the provided positive and negative electrodes is small, higher pressure must be applied to generate an internal short circuit of the battery cell. There is a limit to selecting battery defects by applying a high pressure to the battery cell because the equipment may be damaged, and equipment may be damaged due to a heavy load on the equipment.

Republic of Korea Patent Publication No. 10-2019-0006920

Accordingly, an object of the present invention is to target a plurality of battery cells within a short time, to detect battery defects due to separator damage such as separator tear, separator fold, separator puncture, etc. with high accuracy, regardless of the size of the electrode or the size of the separator damage area. It is to provide selection technology.

However, the objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the description below.

In order to solve the above problems,

In one embodiment, the present invention

a plurality of pressing members disposed to face each other with a cell insertion space in which the battery cells are disposed, and moved to narrow a distance from each other to pressurize the body of the battery cell; and

A detector for measuring one or more of current, voltage, and resistance of the battery cell pressed by the pressing member;

The pressing member has a buffer pad on a pressing surface in contact with the battery cell,

The buffer pad,

a flat pressing unit facing an area in which the electrode assembly of the battery cell is accommodated; and

Provided is a pressurized short-circuit inspection device for a secondary battery including a taper pressurizing part extending from the pressurizing part to press the edge of the battery cell and having an inclination structure from the inside to the outside.

In this case, the tapered pressing portion has an inclined structure in which an average thickness increases as it progresses from the inside to the outside, and the average thickness of the inside of the tapered pressing portion may be smaller than the average thickness of the flat pressing portion.

In addition, the inclined structure of the taper pressing unit may have an inclination of 0.5° to 10°.

In addition, the buffer pad is polyurethane, latex, silicone, butadiene rubber (BR, Butadiene Rubber), styrene-butadiene rubber (SBR, Styrene-Butadiene Rubber), nitrile-butadiene rubber (NBR, Nitrile-butadiene Rubber), ethylene propylene It may include at least one selected from the group consisting of diene monomer (EPDM, Ethylene Propylene Diene Monomer) rubber, polychloroprene rubber (CR, Polychloroprene Rubber), and porous pulp.

In addition, the plurality of pressing members may be disposed in parallel and simultaneously press in one direction.

In addition, the plurality of pressing members may include a pressing jig for applying pressure from one side of the pressing member; and a load cell for measuring the pressure applied to the pressing member.

In addition, a pressure of 1 MPa to 5 MPa may be applied to the pressing member.

Furthermore, the detection unit may include a power source for applying a voltage to the secondary battery; And it may include a current measuring device for measuring the current leaked from the battery cell.

Here, the current measuring device may determine that the battery is defective when an average value of the leakage current measured for 2 to 10 seconds exceeds a reference value.

In addition, the applied voltage of the power may have a range from the open circuit voltage (OCV) of the battery cell to the open circuit voltage (OCV) +500 μV.

An apparatus for detecting a pressurized short circuit of a secondary battery according to the present invention includes a pressurizing member for pressurizing the body of a battery cell and a detection unit for measuring current, voltage, resistance, etc. Provided with a pad, but the buffer pad introduces a taper pressing part to the edge of the battery cell where damage such as tearing, folding, puncture, etc. of the separator mainly occurs, regardless of the size of the electrode or the size of the damaged part of the separator. Under low pressure conditions, high It has the advantage of being able to detect defects with reliability.

In addition, the secondary battery pressurized short circuit inspection device can select a plurality of battery cells within a short time and is easily applied to the secondary battery manufacturing process, specifically, the activation process, so that the productivity of the secondary battery can be improved. There are advantages that can be

1 is an image showing a folded state of a separator sheet of a stack-folding type electrode assembly.
2 and 3 are schematic diagrams briefly showing the configuration of the secondary battery voltage short circuit test device according to the present invention.
4 is a plan view showing an example of a pressing member and a battery pressurized by the pressurized short-circuit tester for a secondary battery according to the present invention.
5 and 6 are plan views illustrating examples of a pressurizing member of a conventional secondary battery pressurized short-circuit tester and a battery pressurized by the pressurizing member.
7 is a cross-sectional view showing the structure of a secondary battery voltage short circuit test device according to the present invention.

Since the present invention can have various changes and various embodiments, specific embodiments will be described in detail in the detailed description.

However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In the present invention, the term "comprises" or "has" is intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Further, in the present invention, when a part such as a layer, film, region, plate, etc. is described as being “on” another part, this includes not only the case where it is “directly on” the other part, but also the case where another part is present in the middle thereof. . Conversely, when a part such as a layer, film, region, plate, or the like is described as being “under” another part, this includes not only being “directly under” the other part, but also the case where there is another part in the middle. In addition, in the present application, being disposed "on" may include the case of being disposed not only on the upper part but also on the lower part.

Hereinafter, the present invention will be described in more detail.

Secondary battery pressurized short circuit inspection device

In one embodiment, the present invention

a plurality of pressing members disposed to face each other with a cell insertion space in which the battery cells are disposed, and moved to narrow a distance from each other to pressurize the body of the battery cell; and

A detector for measuring one or more of current, voltage, and resistance of the battery cell pressed by the pressing member;

The pressing member has a buffer pad on a pressing surface in contact with the battery cell,

The buffer pad,

a flat pressing unit facing an area in which the electrode assembly of the battery cell is accommodated; and

Provided is a pressurized short-circuit inspection device for a secondary battery including a taper pressurizing part extending from the pressurizing part to press the edge of the battery cell and having an inclination structure from the inside to the outside.

As shown in FIG. 2, the pressurized short-circuit inspection device for a secondary battery according to the present invention (hereinafter referred to as 'inspection device') allows a plurality of battery cells 130, specifically, a plurality of pouch-type battery cells to face each other. A plurality of pressing members 110 that pressurize the battery cell 130 by providing a space to be inserted and moving to narrow the space, and at least one of the electrical characteristics of the pressurized battery cell, that is, current, voltage, and resistance. Includes a detection unit 140 for measuring.

At this time, the pressure member 110 may have a buffer pad 120 on a pressure surface S in contact with the battery cell, and the buffer pad may have a surface structure capable of pressing the battery cell with a low pressure.

Specifically, as shown in FIG. 3, the pressing members 221a and 221b include a flat pressing portion 222 facing the region in which the electrode assembly of the battery cell is accommodated, that is, the central region of the battery cell 230; It includes a tapered pressing part 223 extending from the flat pressing part to press the edge of the battery cell and having an inclined structure from the inside to the outside.

The buffer pads 221a and 221b of the present invention may be provided on the front surface (S) in contact with the battery cell 230 to prevent external damage to the battery cell during inspection, and damage such as tearing, folding, or piercing of the separator The edge of the battery cell 230 where the positive electrode, the negative electrode, and the end of the separator are located by having a tapered pressing portion 223 having an inclined structure from the inside to the outside at the edge of the battery cells 130 and 230, which are mainly generated, that is, It is possible to effectively pressurize the end region of the electrode assembly. Through this, since an internal short circuit of the battery cell 230 can be easily induced in a low pressure range in which additional battery cell 230 is not damaged, defects in the secondary battery are screened with high reliability even if the damaged area of the separator is small. can do.

To this end, in the buffer pads 221a and 221b, tapered pressing parts 223 having an inclined structure are disposed at the edges of the battery cells 230 where the ends of the electrode assemblies are located. In order to effectively press, the taper pressing portion 223 has an inclined structure in which the average thickness increases as it progresses from the inside to the outside, and the average thickness of the inside of the taper pressing portion 223 is greater than the average thickness of the flat pressing portion 222. can be thin

Figure 4 (a) is a cross-sectional structure of the battery edge region where the electrode leads 231 and/or 232 of the battery cell are located, and Figure 4 (b) shows the gas generated inside the battery cell 230 during the activation process. It shows the cross-sectional structure of the battery edge region adjacent to the side where the electrode leads 231 and/or 232 are disposed to be removed.

As shown in FIG. 4, the buffer pads 221a and 221b according to the present invention have a sloped structure in which the average thickness increases as they progress from the inside to the outside, so that the taper pressing portion 223 is formed to pressurize the battery cell 220. When the buffer pad completely covers the edge of the battery cell along the end of the battery assembly, the pressure may be applied. Accordingly, since the pressure uniformly acts on the edge of the battery cell, fine separator damage can be precisely measured even under low pressure conditions.

In addition, the inside of the tapered pressing portion 223 may have an average thickness smaller than that of the flat pressing portion 22 to form a stepped structure. This stepped structure serves as a lever and can apply relatively high pressure to the edge of the battery cell under low pressure conditions when pressurized, so that the damage to the separator can be precisely measured without inducing additional damage to the battery cell. In addition, it is possible to improve fairness by minimizing the load of the inspection device in terms of facilities.

At this time, in the buffer pad 220, the flat pressing portion 222 may have an average thickness of 1 to 10 mm, specifically 3 to 9 mm; or an average thickness of 5 to 8 mm. The average thickness may be defined as the length of the flat pressing part 222 corresponding to the distance from the pressing member () to the battery cell. If the thickness of the flat pressing part 222 is too thin, it is not preferable to effectively press the defective part, and if the thickness is too thick, the edge of the battery cell may be damaged.

In addition, it is sufficient if the length of the buffer pad corresponds to the width of the battery cell to be inspected or the length of the battery cell to be inspected. The length of the buffer pad is a length corresponding to the width of the battery cell, and the length of the buffer pad is a length corresponding to the length of the battery cell.

In addition, the inclined structure of the taper pressing part 223 may have an inclination (α) of 0.5 ° to 10 °, specifically 0.5 ° to 7.5 °; 0.5° to 5°; Alternatively, it may have an inclination of 1° to 3°. In the present invention, by controlling the inclination α of the inclined structure of the taper pressing unit 223 within the above range, it is possible to prevent damage to the separator in a narrow area from being detected due to a low angle of less than 0.5°, thereby preventing reliability from deteriorating. Due to the high angle exceeding , high pressure is applied to the edge of the battery cell, so that additional damage to the electrode assembly may be prevented.

In addition, the material of the buffer pad is not particularly limited, but materials with too low hardness can damage the appearance by increasing the pouch case while stretching, and materials with too high hardness cause the positive and negative electrodes to contact in the area where the separator is damaged. Not effective. Therefore, elastic natural rubber or synthetic polymer materials or polyurethane-based polymer materials may be applied.

As an example, the buffer pad may be made of polyurethane, latex, silicone, butadiene rubber (BR), styrene-butadiene rubber (SBR), or nitrile-butadiene rubber (NBR). , Ethylene Propylene Diene Monomer (EPDM) rubber, polychloroprene rubber (CR, Polychloroprene Rubber), and one or more selected from the group consisting of porous pulp, more specifically, polyurethane can do.

On the other hand, in the present invention, as mentioned above, the plurality of pressing members, battery cells are interposed between each pressing member. Specifically, a plurality of pressing members are arranged in a vertical line on a lower base plate (not shown), and may be arranged in parallel so that battery cells can be face-to-face inserted between the arranged pressing members.

More specifically, in the plurality of pressing members, a load cell (not shown) for measuring the pressure applied to the pressing member is mounted on one side of one of a pair of pressing members disposed at the outermost part of the pressing member, The other side is provided so as to come into contact with a pressure jig (not shown) for applying pressure to the pressure member, and the center is a type in which battery cells are mounted.

The load cell is mounted between an outermost pressing member and an adjacent pressing member, and is a device for sensing pressure. Specifically, the load cell measures the pressure in kgf unit when pressure is applied to the battery cell existing between each pressing member by the pressure jig so that an appropriate level of pressure can be applied. That is, it serves to measure the pressing force so that the battery cell is not physically damaged. If the pressing force is too high, there is a problem that the electrodes in the battery cell may be detached or the appearance of the battery container may be damaged. .

The pressing jig is located in contact with the outermost pressing member where the load cell is not located. A pressure jig is a device that applies pressure to one side of an adjacent pressure member. Specifically, the pressing jig induces internal short-circuiting of the battery cells by pressing the battery cells located between the pressing members. The shape of the pressing jig is preferably a flat shape, and the size may correspond to the flat surface of the pressing member.

The pressure applied by the pressing jig may be the same as the pressure applied by the pressing member to the battery cell, and at this time, an appropriate value is selected in consideration of the thickness of the electrode assembly, the thickness of the pouch, the pressing time, the physical properties of the separator, etc. It can be.

Specifically, the pressure applied to the battery cell by the pressing member may be 1 to 5 MPa, and more specifically, 2.83 to 3.34 MPa. If the pressure is less than 1 MPa, it is difficult to detect defects because appropriate pressure cannot be applied to the battery cell, and if the pressure exceeds 5 MPa, the battery cell may be damaged.

The detection unit 140 is equipment for inspecting the current of the pressurized battery cell, and includes a power source (not shown) for applying voltage to the battery cell and a current measuring device (not shown) for measuring leakage current.

The power source includes a voltage generator for generating voltage to apply voltage to a plurality of battery cells and a connection terminal connected to electrode leads of each battery cell to apply the voltage supplied from the voltage generator to each battery cell. can be provided

The current measuring device measures leakage current flowing through a battery cell to which a voltage is applied by a power source. After applying a voltage to the battery cell, the current measuring device can determine whether or not an internal short circuit has occurred in the battery cell by directly measuring the leakage current, thereby detecting a defective battery cell.

The range of the applied voltage may have a range from the open circuit voltage (OCV) of the battery cell measured in the previous step to +500 μV based on the open circuit voltage (OCV), and specifically, is from the open circuit voltage to the open circuit voltage The standard may be +100 ㎶, and more specifically, the open circuit voltage to the open circuit voltage standard +50 ㎶; Alternatively, it may have a range from the open circuit voltage (OCV) of the battery cell to the open circuit voltage (OCV) +20 μV. When the value of the applied voltage exceeds the open circuit voltage standard +500㎶, the battery cell is charged, resulting in a decrease in the rate of change in voltage per capacity. There is a problem in that it takes a long time for the current to stabilize.

As described above, when a constant voltage is applied to a battery cell, in the case of a battery cell in which an internal short circuit occurs due to pressurization, more current is required to maintain the applied voltage, so that the battery cell has a larger leakage current value than a normal battery cell. do.

Therefore, the inspection device of the present invention can sort out the battery cells in which the measured leakage current exceeds a predetermined reference value as defective secondary batteries due to a defect in the separator.

The leakage current uses an average value of leakage currents measured for 2 to 10 seconds. Specifically, by comparing the average value of the current measured for 2 to 10 seconds with a set reference value, it is possible to sort out a defective secondary battery due to a defect in the separator.

In one embodiment of the present invention, 0.08 mA was set as a defective reference value, and battery cells having an average leakage current value exceeding 0.08 mA were detected as defective secondary batteries, resulting in an accuracy close to 100%. In addition, according to one embodiment of the present invention, when the pressure applied by the pressure jig increases, the current value difference between the good secondary battery and the defective secondary battery may increase to 0.1 mA or more.

The inspection device according to the present invention has the above-described configuration, so that defects can be detected with high reliability under low pressurization conditions regardless of the size of the electrode or the size of the damaged portion of the separator, and target a plurality of battery cells in a short time Since it is possible to select and is easily applied to a manufacturing process of a secondary battery, specifically, an activation process, there is an advantage of improving the productivity of the secondary battery.

Hereinafter, the present invention will be described in more detail by examples and experimental examples.

However, the following Examples and Experimental Examples are merely illustrative of the present invention, and the contents of the present invention are not limited to the following Examples and Experimental Examples.

Examples 1 and 2.

A pressurized short-circuit inspection device 1000 as shown in FIG. 7 was manufactured. At this time, the buffer pad provided to the pressing member 1100 has a cross-sectional structure including a taper pressing portion as shown in FIG. 3 . At this time, the average thickness of the flat pressing part of the buffer pad, the average thickness of the inside of the tapered pressing part, and the inclination of the inclined structure are shown in Table 1 below.

flat pressing part Taper pressing part median average thickness inclined structure gradient Example 1 9㎛ 7㎛ 3° Example 2 9㎛ 7㎛ 15°

Comparative Examples 1 and 2.

A pressurized short-circuit inspection device 1000 as shown in FIG. 7 was manufactured. At this time, the buffer pad provided to the pressing member 1100 was used having a cross-sectional structure as shown in FIGS. 5 and 6, respectively, and the average thickness of the flat pressing part and the average thickness of the stepped pressing part of the buffer pad are as shown in Table 2 below. same.

Cross-sectional structure of buffer pad Average thickness of flat pressing part Average thickness of the stepped pressing part Comparative Example 1 Structure of Figure 5 9㎛ 0㎛ Comparative Example 2 Structure of Figure 6 9㎛ 2㎛

experimental example.

For the pressurized short-circuit inspection devices prepared in Examples and Comparative Examples, defect detection ability was evaluated according to the degree of damage to the separator.

Specifically, a battery cell having a damage of 0.1 to 10 mm on the separator was prepared, mounted on the pressurized short circuit inspection device of Examples and Comparative Examples, and then activated charge / discharge at 25 ° C was performed twice at 0.02 C / 0.05 C. After that, the standard charging current density was set to 0.5C to full charge. After discharging a fully charged battery cell to SOC 10% at a C-rate of 0.02C, a voltage of +100㎶ based on the open circuit voltage (OCV) of the battery cell is applied to the battery cell and the voltage of the cell is measured to determine the leakage current. The size of damage to the separator provided in the generated cell was confirmed. In the same way, the minimum damage length and reliability of the separator detectable by each pressurized short circuit tester were evaluated, and the results are shown in Table 3 below.

Minimum detectable damage length longitudinal direction thickness direction tear folding tear folding Example 1 0.5mm≤ 0.6mm≤ 0.5mm≤ 0.6mm≤ Example 2 0.8mm≤ 0.7mm≤ 0.7mm≤ 0.6mm≤ Comparative Example 1 2mm≤ 1mm≤ 2mm≤ 1mm≤ Comparative Example 2 1mm≤ 0.8mm≤ 1mm≤ 0.8mm≤

As shown in Table 3, the pressurized short circuit test apparatus according to the present invention is provided with a buffer pad having a structure in which a taper pressurizing part is introduced in the edge region of the battery cell, and can detect 0.5mm separator damage with high reliability of 99% or more. confirmed to be

From these results, it can be seen that the pressurized short-circuit inspection device according to the present invention can detect defects with high reliability under low pressurization conditions regardless of the size of the electrode or the size of the damaged portion of the separator.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art or those having ordinary knowledge in the art do not deviate from the spirit and technical scope of the present invention described in the claims to be described later. It will be understood that various modifications and changes can be made to the present invention within the scope.

Therefore, the technical scope of the present invention is not limited to the contents described in the detailed description of the specification, but should be defined by the claims.

100, 200, 300, 400 and 1000: Pressurized short-circuit inspection device for secondary batteries
110: pressing member
211a, 311a and 411a: first pressing member
211b, 311b and 411b: second pressing member
120: buffer pad
221a, 321a and 421a: first buffer pad
221b, 321b and 421b: second buffer pad
222 and 422: flat pressing part
223: taper pressing part
424: stepped pressing unit
1, 130, 230, 330 and 430: battery cell
131, 231, 331 and 431: positive lead
132, 232, 332 and 432: negative lead
233: gas pocket part
1100: pressing member
1110: electrode lead gripper
1200: pressing member driving means
1210: driving plate
1220: drive shaft
S: the surface of the buffer pad in contact with the secondary battery

Claims (10)

a plurality of pressing members disposed to face each other with a cell insertion space in which the battery cells are disposed, and moved to narrow a distance from each other to pressurize the body of the battery cell; and
A detector for measuring one or more of current, voltage, and resistance of the battery cell pressed by the pressing member;
The pressing member has a buffer pad on a pressing surface in contact with the battery cell,
The buffer pad,
a flat pressing unit facing an area in which the electrode assembly of the battery cell is accommodated; and
A pressurized short-circuit inspection device for a secondary battery including a taper pressurizing part extending from the pressurizing part to press the edge of the battery cell and having an inclined structure from the inside to the outside.
According to claim 1,
The taper pressing part has an inclined structure in which the average thickness becomes thicker as it progresses from the inside to the outside.
The average thickness of the inner side of the tapered pressing part is smaller than the average thickness of the flat pressing part.
According to claim 1,
The inclination structure of the taper pressing part has an inclination of 0.5 ° to 10 ° secondary battery pressurized short-circuit inspection device.
According to claim 1,
The buffer pad is made of polyurethane, latex, silicone, butadiene rubber (BR), styrene-butadiene rubber (SBR), nitrile-butadiene rubber (NBR), ethylene propylene diene monomer ( EPDM, Ethylene Propylene Diene Monomer) rubber, polychloroprene rubber (CR, Polychloroprene Rubber), and a pressurized short circuit inspection device for secondary batteries containing at least one selected from the group consisting of porous pulp.
According to claim 1,
A plurality of pressing members are arranged in parallel and pressurized at the same time in one direction.
According to claim 1,
A plurality of pressing members,
A pressure jig for applying pressure from one side of the pressure member; and
A pressurized short-circuit inspection apparatus for a secondary battery further comprising a load cell for measuring a pressure applied to the pressurizing member.
According to claim 1,
The pressurizing member is a pressurized short-circuit tester for a secondary battery to which a pressure of 1 MPa to 5 MPa is applied.
According to claim 1,
detection unit,
a power source for applying a voltage to the battery cell; and
A pressurized short-circuit inspection device for a secondary battery comprising a current measuring device for measuring a current leaked from a battery cell.
According to claim 8,
The current measuring device is a voltage short circuit inspection device for a secondary battery that determines that the battery is defective when the average value of the leakage current measured for 2 to 10 seconds exceeds a reference value.
According to claim 8,
The applied voltage of the power supply is a voltage short circuit inspection device for a secondary battery having a range of the open circuit voltage (OCV) of the battery cell to the open circuit voltage (OCV) +500 μV.

Images