KR20220157634A - Quality Inspection Device and Method of Pouch Type Secondary Battery Cells - Google Patents

Abstract

The present invention relates to a quality inspection device and method of pouch-type secondary battery cells, the object of which is to inspect the quality of an electrode plate, a bent portion, a welded part, or the like of pouch-type secondary battery cells. An AC signal-generating part generates an AC signal, and a magnetic field-generating part generates a magnetic field according to the generated AC signal to allow an induced current to flow through a pouch-type secondary battery cell. One or more induced current detection sensors each detect a signal of an induced current flowing into the pouch-type secondary battery cell. The detected signal of the induced current is compared with a value of a judgment range previously stored in a control/determination part, and the quality of the pouch-type secondary battery cell is judged.

Description

Quality Inspection Device and Method of Pouch Type Secondary Battery Cells

The present invention relates to a pouch-type secondary battery cell quality inspection apparatus and method for inspecting the quality of an electrode plate, a bent portion, or a welded portion of a pouch-type secondary battery cell.

As fossil fuels, which are widely used as energy sources, are gradually depleted, their prices continue to rise. In addition, fossil fuels pollute the environment by emitting many pollutants such as soot. In particular, vehicles using fossil fuels, as one of the main factors that pollute the environment very seriously by emitting a lot of pollutants, there is an urgent need for measures to reduce the use of fossil fuels in vehicles.

Accordingly, the demand for an environmentally friendly alternative energy source that can be widely used throughout the industry without emitting pollutants has emerged as an indispensable factor.

Various environmentally friendly alternative energy sources that do not emit pollutants are known. As one of these environmentally friendly alternative energy sources, a secondary battery capable of driving a power device while repeatedly charging and discharging power is used.

The secondary battery is attracting attention as a new energy source for improving eco-friendliness and energy efficiency in that it can drastically reduce the use of fossil raw materials and does not generate by-products such as pollutants due to the use of electricity.

Recently, secondary batteries are widely used throughout the industry, including portable devices such as smartphones, electric vehicles (EVs) and hybrid vehicles (HVs), and driving devices requiring large amounts of power. have. In addition, the charging capacity of secondary batteries is continuously increasing.

As one of the above secondary batteries, a pouch type secondary battery is known. The pouch-type secondary battery is configured by combining a plurality of pouch-type secondary battery cells.

The pouch-type secondary battery cell is repeatedly laminated with a separator interposed between the positive electrode plate and the negative electrode plate. Then, the electrodes of the stacked positive electrode plate and the electrode of the negative electrode plate are compressed, respectively, and the positive terminal and the negative terminal are welded to the compressed electrode of the positive electrode plate and the electrode of the negative electrode plate, respectively. In addition, the laminated cathode plate, separator, and cathode plate are configured to be wrapped together with an electrolyte, for example, in a pouch made of an aluminum film.

Such a pouch-type secondary battery cell is configured such that only positive terminals and negative terminals are exposed to the outside of the pouch.

The pouch-type secondary battery cell can be manufactured with little internal deformation and no empty space. In addition, since the pouch-type secondary battery cell can be manufactured in various shapes, it has a very high degree of design freedom, a light weight, and a very high energy density.

When manufacturing such a pouch-type secondary battery cell, various defect factors may occur.

For example, in the process of stacking the positive electrode plate and the negative electrode plate with a separator interposed therebetween, defects such as fine cracks or disconnection may occur in the positive electrode plate and the negative electrode plate.

In addition, in the process of pressing the electrodes of the plurality of positive electrode plates and the electrodes of the negative electrode plate, a bent portion is generated where the ends of the positive electrode plate and the negative electrode plate are bent between the electrodes, and the bent portion is bent to cause fine cracks or disconnections. Defects may occur.

In addition, in the process of welding the positive terminal and the negative terminal to the crimped electrode, welding defects in which the electrode is not welded to the positive terminal and the negative terminal may occur.

These defects hinder the flow of current charged and discharged in the pouch type secondary battery cell. As a result, the current flowing to the portion where the defect occurs is reduced, and the flow of current is relatively concentrated to the portion where the defect is not generated.

Therefore, a lot of current flows in the area where the defect does not occur, and overheating may occur. In addition, an overheating phenomenon may occur in a defective area due to a high resistance value. Safety accidents such as fire may occur in the secondary battery due to such an overheating phenomenon.

Therefore, after manufacturing the pouch-type secondary battery cell, whether or not defects such as cracks or disconnections have occurred in the entire area of the pouch-type secondary battery cell, that is, the positive electrode plate and the negative electrode plate, or the bent portion of the electrode, and the welding defect of the electrode There is a demand for a highly reliable inspection device capable of precisely inspecting.

Republic of Korea Patent Registration No. 10-2023739 (registered on September 16, 2019) is known as a prior art for inspecting the quality of a pouch-type secondary battery cell.

According to the prior art described above, a first sensor for inducing eddy current into a secondary battery cell and a second sensor for detecting an eddy current signal induced by the first sensor are included, and an inspection by eddy current is performed while the secondary battery cell is running. An inspection unit that performs an inspection, a transfer unit that sequentially transfers a plurality of secondary battery cells from the point where the secondary battery cells are put in to the point where they are taken out, and electrically connected to the inspection unit, receiving an eddy current signal detected by the inspection unit to A control unit for evaluating and controlling, wherein the inspection unit is designed to move the first sensor and the second sensor to a position to be inspected, and inspects by eddy current while the first sensor and the second sensor are fixed It is configured to detect cracks inside the pouch-type secondary battery cell using eddy current.

This prior art uses eddy currents in a non-destructive way to detect the presence and location of fine cracks or disconnections at the electrodes and electrodes of the positive and negative electrodes of the pouch-type secondary battery cell, and also the welding defects of the welded part can be detected.

In general, when manufacturing a pouch-type secondary battery cell, the height, bending angle, and width of the bent portion are not constant and occur in various forms. In addition, the position, direction, width, and shape of the crack or disconnection are not constant, and they occur in various forms. In addition, the pouch-type secondary battery cells manufactured due to the influence of the electrolyte and the welding part are not uniform, and slight differences occur between each other.

The above eddy current method responds very sensitively to the measurement distance between the pouch type secondary battery cell and the sensors. That is, according to the measurement distance, defects in the electrode plate and the bent portion of the pouch-type secondary battery cell and defects in the welding portion of the electrode are detected differently.

Therefore, the prior art described above has limitations in precisely inspecting whether or not the pouch type secondary battery cell is defective.

In addition, since the pouch-type secondary battery cell is inspected for defects by generating eddy current only in a local area, there is a limit to inspecting all electrodes, electrodes, and welded parts of the pouch-type secondary battery cell.

In addition, when the pouch-type secondary battery cell is deformed or there is a positional error between the pouch-type secondary battery cell and the sensor, it is difficult to detect whether the pouch-type secondary battery cell is defective.

Therefore, the above-described prior art has hardly been put into practical use.

Republic of Korea Patent Registration No. 10-2023739 (registered on September 16, 2019)

The problem to be solved by the present invention is to allow an induced current to flow through the entire pouch-type secondary battery cell, and to detect the induced current at the electrode plate or bent portion of the pouch-type secondary battery cell, such as fine cracks or disconnections in the electrode plate or the bent portion. Provided is an apparatus and method for inspecting the quality of a pouch-type secondary battery cell capable of precisely inspecting whether or not this has occurred.

In addition, the problem to be solved by the present invention is a pouch-type secondary battery cell that allows an induced current to flow through the entire pouch-type secondary battery cell and detects the induced current at the welding part of the electrode to precisely inspect whether or not the welding part is defective. A quality inspection device and method are provided.

In addition, the problem to be solved by the present invention is a pouch-type secondary battery cell capable of accurately detecting the location of the defect when a defect such as a fine crack or disconnection occurs in the electrode plate or bent portion of the pouch-type secondary battery cell. A quality inspection device and method are provided.

In addition, an object to be solved by the present invention is to provide an apparatus and method for inspecting the quality of a pouch-type secondary battery cell capable of accurately detecting a location where a welding defect occurs at a welding portion of the pouch-type secondary battery cell.

In addition, the problem to be solved by the present invention is to provide a quality inspection device and method for a pouch-type secondary battery cell that can inspect the quality of a pouch-type secondary battery cell without being affected by noise signals or external factors such as dust or moisture. to provide.

In addition, the problem to be solved by the present invention is not limited to the above-mentioned problems, and other problems not mentioned are clearly understood by those skilled in the art from the description below. It could be.

According to the apparatus for inspecting the quality of a pouch-type secondary battery cell of the present invention, an AC signal generator for generating an AC signal, a magnetic field generator for generating a magnetic field according to the AC signal and allowing an induced current to flow through the pouch-type secondary battery cell, At least one induced current detection sensor detecting a signal of an induced current flowing into the pouch-type secondary battery cell, and comparing the signal of the induced current detected by the induced current detection sensor with a value of a judgment range stored in advance, and according to the comparison result A control/determination unit for determining the quality of the pouch-type secondary battery cell may be included.

In addition, the apparatus for inspecting the quality of a pouch-type secondary battery cell of the present invention further includes a power loss detection unit for detecting a power loss of an AC signal generated by the AC signal generator, and the control/determination unit comprises the power loss detection unit With the detection signal, it can be determined whether the one or more induced current detection sensors are located at the starting position where the induced current from the pouch-type secondary battery cell starts to be detected.

The magnetic field generating means includes a transformer that transmits the AC current generated by the AC signal generator, a series resonance unit that makes a coil resonate in series with the low frequency of the AC current to generate a magnetic field, and a parallel resonance with the high frequency of the AC current. It is possible to include a parallel resonator that causes the coil to generate a magnetic field.

In addition, the apparatus for inspecting the quality of a pouch-type secondary battery cell of the present invention further includes one or more signal processing units outputting a signal of the induced current detected by the induced current detection sensor to the control/determination unit, and the AC signal generator, An alternating current signal having a dual frequency of a low frequency and a high frequency is generated, and the signal processing unit detects the low frequency alternating current signal and outputs the low frequency alternating current signal to the control/determination unit; A high frequency detection filter output to the control/determination unit may be included.

In addition, in the apparatus for inspecting the quality of a pouch-type secondary battery cell of the present invention, when the pouch-type secondary battery cell is located at a starting position, the one or more induced current detection sensors scan the pouch-type secondary battery cell while moving the induced current signal can be detected.

In addition, in the pouch-type secondary battery cell quality inspection apparatus of the present invention, the pouch-type secondary battery cell and the one or more induced current detection sensors are fixed, and the signal of the induced current is scanned by the one or more induced current detection sensors. To be detected, the pouch type secondary battery cell may move.

A shielding means for shielding a magnetic field of the magnetic field generating means may be further included between the magnetic field generating means and the induced current detection sensor.

And the method for inspecting the quality of a pouch-type secondary battery cell of the present invention includes the steps of the AC signal generator generating an AC signal and the magnetic field generating means generating a magnetic field according to the generated AC signal so that the induced current flows into the pouch-type secondary battery cell, The step of detecting a signal of an induced current flowing to the pouch-type secondary battery cell by an induced current detection sensor, and comparing the signal of the induced current detected by the induced current detection sensor with a value of a judgment reference range by a control/determination unit to determine the pouch type secondary battery cell. A step of determining the quality of the secondary battery cell may be included.

According to the apparatus and method for inspecting the quality of a pouch-type secondary battery cell of the present invention, an induced current flows through the pouch-type secondary battery cell. In addition, the induced current flowing into the pouch-type secondary battery cell is detected at the electrode plate and the bent portion to determine whether cracks or disconnections occur, as well as the induced current flowing into the pouch-type secondary battery cell is detected at the welding part of the electrode to determine whether the electrode is welded or not. judge

Therefore, according to the present invention, it is possible to accurately detect whether a crack, disconnection, or welding defect has occurred in the pouch-type secondary battery cell by using the induced current detected from the pouch-type secondary battery cell.

In addition, the present invention uses the induced current detected from the pouch-type secondary battery cell when defects such as cracks or disconnections or welding defects of electrodes occur in the pouch-type secondary battery cell to detect cracks, disconnections, or welding defects. can be judged accurately.

In addition, the present invention is not uniform, and induced current flows in pouch-type secondary battery cells manufactured in various forms, and the induced current is detected at the electrode plate, bent portion, and welded portion to determine cracks, disconnections, and welding defects, so that the pouch Even if there is a positional error between the type secondary battery cell and the sensor, there is an effect of precisely inspecting whether or not the pouch type secondary battery cell is defective.

Hereinafter, the present invention will be described in more detail through an embodiment that does not limit the present invention with reference to the accompanying drawings, and the same reference numerals are assigned to the same elements in some drawings.
1 is a view briefly showing the configuration of a general pouch-type secondary battery cell;
2 is a view for explaining an operation in which an induced current flowing to a pouch-type secondary battery cell flows according to the present invention;
3a to 3d are diagrams showing embodiments of the installation position of the magnetic field generating means according to the present invention;
4a and 4b are views for explaining an operation of inspecting a pouch-type secondary battery cell according to the present invention;
5a to 5c are views for explaining the induced current detected by the induced current detection sensor when there is a defect such as a fine crack or disconnection in a bent portion;
6A to 6C are views for explaining the induced current detected by the induced current detection sensor when there is a defect such as a fine crack or disconnection in the electrode plate;
7 is a block diagram showing the configuration of the quality inspection device of the present invention;
8 is a detailed circuit diagram of the magnetic field generating means of FIG. 7;
Figure 9 is a block diagram showing the configuration of each of the plurality of signal processing units of Figure 7, and
10 is a signal flow diagram showing a quality inspection method according to the present invention.

The following detailed description is merely an example, and merely illustrates an embodiment of the present invention. In addition, the principles and concepts of the present invention are presented for the purpose of being the most useful and readily explainable.

Therefore, it is not intended to provide more detailed structure than necessary for a basic understanding of the present invention, and various forms that can be practiced in the substance of the present invention by those skilled in the art are illustrated through the drawings.

1 is a diagram briefly showing the configuration of a general pouch-type secondary battery cell. Referring to FIG. 1 , a pouch-type secondary battery cell 100 may include a plurality of positive electrode plates 110, a plurality of negative electrode plates 120, and a plurality of separators 130.

A separator 130 is interposed between each of the plurality of positive electrode plates 110 and each of the plurality of negative electrode plates 120 and is repeatedly and sequentially stacked.

One side of the plurality of positive electrode plates 110 is formed to slightly protrude from one side of the plurality of separators 130, and the other side of the plurality of negative electrode plates 120 also protrudes from one side of the plurality of separators 130. It is laminated so that it protrudes slightly from.

Here, the length of the protruding positive electrode plate 110 and the negative electrode plate 120 may be determined differently depending on, for example, the total number of the positive electrode plate 110, the negative electrode plate 120, and the separator 130 and the total stacking height. can

In addition, an electrode 150 for welding the positive terminal 140 is integrally formed at each end of one side of the plurality of positive electrode plates 110 . In addition, an electrode 160 for welding the negative terminal 142 is integrally formed on each of the ends of the other side of the plurality of negative electrode plates 120 .

Here, the formation of the electrode 150 at the end of one side of the plurality of positive electrode plates 110 and the formation of the electrode 160 at the end of the other side of the plurality of negative electrode plates 120 have been illustrated and described as an example. . In carrying out the present invention, the present invention is not limited thereto, and the electrodes 150 and 160 are located in various positions, including the side surfaces of the plurality of positive electrode plates 110 and the plurality of negative electrode plates 120 to prevent shorting with each other. may be formed.

When the positive terminal 140 and the negative terminal 142 are joined to the electrodes 150 and 160 by welding, respectively, the plurality of electrodes 150 and 160 are pressed at a predetermined pressure from the top and bottom, respectively, The positive terminal 140 and the negative terminal 142 are joined to the compressed electrodes 150 and 160 by welding, respectively.

In addition, the plurality of positive electrode plates 110, the plurality of negative electrode plates 120, the plurality of separators 130, and the entirety of the electrodes 150 and 160 are mixed with a predetermined electrolyte into the pouch 170. ) to seal.

Here, the pouch 170 may be formed of, for example, an aluminum film.

Therefore, the pouch type secondary battery cell 100 may be configured such that only the terminals 140 and 142 are exposed to the outside of the pouch 170 .

In such a pouch-type secondary battery cell 100, in the process of stacking a plurality of positive electrode plates 110 and a plurality of negative electrode plates 120 with separators 130 interposed therebetween, the positive electrode plate 110 and the negative electrode plate 120 Defects such as fine cracks or disconnections may occur in the field.

And, in the process of compressing the electrodes 150 and 160, one end of the positive electrode plate 110 and the other end of the negative electrode plate 120 are bent to generate bent portions 112 and 122, and the bent portion (112) Defects such as fine cracks or disconnection may occur in (122).

Here, the positive electrode plate 110 and the negative electrode plate 120 do not protrude from the separator 130, and the electrodes 150 and 160 are formed to protrude from the separator 130, so that the bent portion 112 122 may be formed on the electrodes 150 and 160.

In the process of welding the positive terminal 140 and the negative terminal 142 by pressing the electrodes 150 and 160, respectively, the electrode 150 and the positive terminal 140 are not welded accurately or the electrode ( 160) and the negative electrode terminal 142 may be welded incorrectly.

Defects such as fine cracks or disconnections or poor welding cause high-temperature heat generation in the process of charging and discharging power to the pouch-type secondary battery cell, which may cause safety accidents such as fire.

Therefore, in the present invention, an induced current flows through the pouch-type secondary battery cell 100, and the induced current flowing through the pouch-type secondary battery cell 100 is transferred from the electrode plates 110 and 120 and the bent portions 112 and 122. By detecting it, it is possible to accurately detect whether defects such as fine cracks or disconnections have occurred in the electrode plates 110 and 120 or the bent parts 112 and 122.

In addition, in the present invention, an induced current flows through the pouch-type secondary battery cell 100, and the induced current flowing through the pouch-type secondary battery cell 100 is detected by the electrodes 150 and 160, and the electrodes 150 and 160 It is possible to precisely detect whether or not there is a welding defect in the

2 is a view for explaining an operation in which an induced current flowing through a pouch-type secondary battery cell according to the present invention flows. Here, reference numeral 200 denotes a magnetic field generating unit. The magnetic field generating means 200 is, for example, a coil 204 wound around a core 202 a plurality of times. The magnetic field generating unit 200 applies a magnetic field generating signal of a predetermined frequency to the coil 204 to generate a magnetic field.

Then, the magnetic field generating unit 200 generates a magnetic field according to the magnetic field generating signal, and the generated magnetic field is induced to the pouch-type secondary battery cell 100, and the pouch-type secondary battery cell 100 receives the magnetic field signal. An induced current 102 flows accordingly.

For example, the induced current 102 flows in the pouch-type secondary battery cell 100 in the longitudinal direction by the magnetic field generated by the magnetic field generating means 200 .

In the present invention, the magnetic field generating means 200 is located on the upper side of the other side of the pouch-type secondary battery cell 100, as shown in FIG. can be made

In addition, as shown in FIG. 3B, the magnetic field generating means 200 is positioned on the upper and lower sides of the pouch-type secondary battery cell 100, respectively, so that the induced current 102 flows through the pouch-type secondary battery cell 100. can do.

In addition, as shown in FIG. 3C, the magnetic field generating means 200 may be positioned above the middle portion of the pouch-type secondary battery cell 100 so that the induced current 102 flows through the pouch-type secondary battery cell 100. .

In addition, as shown in FIG. 3D, the induced current 102 flows through the pouch-type secondary battery cell 100 by positioning the magnetic field generating means 200 at the upper and lower parts of the middle part of the pouch-type secondary battery cell 100, respectively. can be made

In FIGS. 3A to 3D , the position of the magnetic field generating means 200 that allows the induced current 102 to flow to the pouch-type secondary battery cell 100 has been illustrated and described as an example.

In carrying out the present invention, the present invention is not limited thereto, and the magnetic field generating means is located at various positions where the induced current 102 can flow to the pouch-type secondary battery cell 100, including one side of the pouch-type secondary battery cell 100. 200 can be positioned.

In addition, as the magnetic field generating signal applied to the magnetic field generating unit 200 to generate the magnetic field, AC signals of various shapes including, for example, a sine wave or a square wave having a frequency of 60 Hz to 1 MHz may be used.

The induced current 102 flowing to the pouch-type secondary battery cell 100 has a high frequency characteristic, and when the frequency is high, the induced current 102 flowing to the surface layer of the pouch-type secondary battery cell 100 is large, and the induced current 102 flowing to the middle layer is large. Current 102 is relatively small compared to the surface layer. And when the frequency is lowered, the induced current 102 flowing to the middle layer portion gradually increases.

Therefore, in carrying out the present invention, in the frequency range of 60 Hz to 1 MHz, using a dual frequency AC signal synthesized with a selected low frequency and a high frequency, whether there are defects in all layers of the pouch-type secondary battery cell 100 It is desirable to examine whether

Here, the magnetic field generating means 200 is shown as an example in which a coil 204 having a rectangular cross section is wound around a core 202 a plurality of times. In carrying out the present invention, it is not limited thereto, and the magnetic field generating means 200 may be configured by winding a copper wire coated with enamel on the core 202 multiple times with the coil 202. may be

4A and 4B are views for explaining an operation of inspecting the quality of the pouch-type secondary battery cell 100 according to the present invention. As shown in FIG. 4A, when the pouch-type secondary battery cell 100 is transported by a transport means (not shown) such as a conveyor belt and arrives at an inspection position, the pouch-type secondary battery A magnetic field generating unit 200 is positioned above the cell 100 .

Here, the position of the magnetic field generating means 200 shown in the drawing is shown as an example, and in carrying out the present invention, as described above, the magnetic field is located at various positions to allow the induced current to flow to the pouch-type secondary battery cell 100. The generating means 200 can be positioned.

In addition, four induced current detection sensors 300 (300a to 300d) may be positioned adjacent to the pouch-type secondary battery cell 100 to scan the pouch-type secondary battery cell 100 and detect the induced current.

For example, an induced current detection sensor 300a may be positioned to detect an induced current by scanning an upper portion of the bent portions 112 and 122 of the pouch type secondary battery cell 100 . In addition, an induced current detection sensor 300b may be positioned to detect the induced current by scanning the lower portions of the bent parts 112 and 122 of the pouch type secondary battery cell 100 . In addition, an induced current detection sensor 300c for detecting an induced current by scanning an upper portion of the electrode plate 110 of the pouch type secondary battery cell 100 may be positioned. In addition, an induced current detection sensor 300d for detecting an induced current by scanning a lower portion of the electrode plate 110 of the pouch type secondary battery cell 100 may be positioned.

Here, the four induced current detection sensors 300 (300a to 300d) are shown as examples, and in carrying out the present invention, the number of induced current detection sensors 300 may be increased or decreased or the installation position may be changed as necessary. .

In this state, when an AC signal is applied to the coil 204 of the magnetic field generating means 200, the magnetic field generating means 200 generates a magnetic field. The magnetic field generated by the magnetic field generating unit 200 is induced to the pouch-type secondary battery cell 100, and thus an induced current flows in the pouch-type secondary battery cell 100.

In addition, the plurality of induced current detection sensors 300 (300a to 300d) scan the pouch-type secondary battery cell 100 in the width direction to detect induced current, respectively.

Here, when there is a defect such as a fine crack or disconnection in the electrode plate 110, 120 or the bent portion 112, 122, the defect is detected by the plurality of induction current detection sensors 300; 300a to 300d, respectively. affect the induced current.

Therefore, in the present invention, the induced current detected by the plurality of induced current detection sensors 300 (300a to 300d) is compared with a preset criterion range to determine whether the induced current is defective.

For example, as shown in FIG. 5A , it is assumed that a fine crack 302 is generated in the electrode 140 of the upper layer.

Then, when the induced current detection sensors 300a and 300b scan the portion of the electrode 140 where the crack 302 has occurred, for example, as shown in FIGS. 5B and 5C, the induced current will detect

That is, FIG. 5B is a graph showing the induced current detected by the upper induced current detection sensor 300a, and FIG. 5C is a graph showing the induced current detected by the lower induced current detection sensor 300b. When the induced current detection sensors 300a and 300b scan the portion of the electrode 140 where no crack occurs, a high induced current is detected, and when the portion of the electrode 140 where the crack occurs is scanned, Low induced current is detected.

This phenomenon is because the induced current flowing to the portion where the crack 302 is generated is reduced, and the induced current flowing to the portion where the crack 302 is not generated is increased as much as the induced current is reduced.

In addition, the induced current detected by the upper induced current detection sensor 300a has a very high fluctuation range and is out of the criterion range, whereas the induced current detected by the lower induced current detection sensor 300b has a fluctuation range of the induced current detection sensor It can be seen that the crack 302 is generated in the layer of the electrode 112 adjacent to the upper surface layer of the pouch-type secondary battery cell 100 as it is lower than the fluctuation range of the induced current detected by (300a).

Therefore, when defects such as cracks 302 occur in the electrodes 140 and 142, the location of defects such as cracks 302 using the induced current detected by the induced current detection sensors 300a and 300b, Approximate depth of occurrence can be determined.

For example, as shown in FIG. 6A , it is assumed that fine cracks 304 are generated in the electrode plates 110 and 120 of the upper layer.

Then, when the induced current detection sensors 300c and 300d scan the parts of the electrode plates 110 and 120 where the cracks 304 are generated, for example, as shown in FIGS. 6B and 6C, the induction detect current.

That is, FIG. 6B is a graph showing the induced current detected by the upper induced current detection sensor 300c, and FIG. 6C is a graph showing the induced current detected by the lower induced current detection sensor 300d. When the induced current detection sensors 300c and 300d scan the cracked areas of the electrode plates 110 and 120, a low induced current is detected, and the areas where the cracks do not occur in the electrode plates 110 and 120 When scanning , a relatively high induced current is detected.

This phenomenon is also because the induced current flowing to the portion where the crack 304 is generated is reduced, and the induced current flowing to the portion where the crack 304 is not generated is increased as much as the induced current is reduced.

In addition, the induced current detected by the upper induced current detection sensor 300c has a very high fluctuation range and is out of the criterion range, while the induced current detected by the lower induced current detection sensor 300d has a fluctuation range of the induced current detection sensor It can be seen that the crack 304 is generated in the layer of the electrode plate 112, 122 adjacent to the surface layer of the pouch-type secondary battery cell 100 as it is lower than the fluctuation range of the induced current detected by (300c).

In this way, the present invention applies a magnetic field signal to the magnetic field generating means 200 so that the induced current flows through the pouch-type secondary battery cell 100, and the plurality of induced current detection sensors 300 are pouch-type secondary battery cells ( 100), each induced current is detected while scanning a plurality of parts.

In addition, the induced currents detected by the plurality of induced current detection sensors 300 are compared with the judgment standard range, and it is determined whether or not defects such as cracks have occurred in the pouch type secondary battery cell 100 according to the comparison result.

In the above, a plurality of induced current detection sensors 300 are positioned based on the pouch-type secondary battery cell 100 located in the correct position, and the plurality of induced current detection sensors 300 are pouch-type secondary battery cells 100 ) is scanned in the width direction to detect the induced current as an example.

In carrying out the present invention, the present invention is not limited thereto, and a plurality of induced current detection sensors 300 are provided in the length direction and width direction of the pouch type secondary battery cell 100 so that the plurality of induced current detection sensors 300 perform a scan operation. It may be configured to detect the induced current in the entire area of the pouch-type secondary battery cell 100 without performing the.

In the above, when the magnetic field generating means 200 is fixed and the pouch-type secondary battery cell 100 is transported, the magnetic field generating means 200 reaches a position where an induced current of sufficient strength flows due to the generated magnetic field. A plurality of induced current detection sensors 300 move and scan the pouch-type secondary battery cell 100 to detect induced current as an example.

In carrying out the present invention, the present invention is not limited thereto, and the magnetic field generating means 200 and the plurality of induced current detection sensors 300 are fixed, respectively, and the pouch-type secondary battery cell 100 is transported while the magnetic field generating means 200 The induced current flows, and the pouch-type secondary battery cell 100 can be scanned with the plurality of induced current detection sensors 300 in a fixed state to detect the induced current. can

In addition, the induced current detected by the plurality of induced current detection sensors 300 may be affected by the magnetic field generated by the magnetic field generating unit 200 .

Therefore, in carrying out the present invention, shielding means for shielding the magnetic field must be further provided so that the magnetic field generated by the magnetic field generating means 200 does not affect the induced current detected by the plurality of induced current detection sensors 300. can

For example, as shown in FIGS. 4A and 4B, the shielding means is provided with a shielding means 400 so that the magnetic material covers the entire area of the magnetic field generating means 200, so that the magnetic field of the magnetic field generating means 200 is protected. can be shielded.

Alternatively, although not shown in the drawings, shielding means may be provided at each of the plurality of induced current detection sensors 300 so that the magnetic field of the magnetic field generating means 200 does not affect the induced current detection sensor 300.

In addition to the above configuration, various shielding means capable of preventing the magnetic field of the magnetic field generating means 200 from affecting the induced current detection sensor 300 may be used.

7 is a block diagram showing the configuration of the quality inspection apparatus of the present invention. Referring to FIG. 7, the quality inspection apparatus of the present invention includes a magnetic field generating means 200, a plurality of induced current detection sensors 300, an AC signal generator 600, a power loss detector 610, It may include a plurality of signal processing units 620, a memory 630, and a determination/control unit 640.

In the quality inspection apparatus of the present invention, the determination/control unit 640 controls the AC signal generator 600 to generate an AC signal.

Here, the AC signal generator 600 may generate AC signals of various shapes, including sine waves or square waves.

And, the frequency of the AC signal is preferably to have a dual frequency combining a low frequency and a high frequency in the range of 60 Hz to 1 MHz.

That is, as described in detail above, the induced current 102 flowing through the pouch-type secondary battery cell 100 is, in terms of frequency characteristics, when the frequency is high, the induced current 102 flowing into the surface layer of the pouch-type secondary battery cell 100 is large, and the induced current 102 flowing into the middle layer is relatively small compared to the surface layer. And when the frequency is lowered, the induced current 102 flowing to the middle layer portion gradually increases.

Therefore, in the present invention, the AC signal generator 600 generates a dual-frequency AC signal synthesized from a selected low frequency and a high frequency in the frequency range of 60 Hz to 1 MHz.

The dual-frequency AC signal generated by the AC signal generator 600 is output to the magnetic field generator 200.

As shown in FIG. 8, the magnetic field generator 200 includes a transformer 210 for transmitting the dual-frequency AC signal generated by the AC signal generator 600 to the coil 204, and the transformer 210 A capacitor 222 is connected in series between the ) and the coil 204, and the low frequency resonator 220 serially resonates at low frequencies, and a capacitor 232 is connected in parallel between the transformer 210 and the coil 204. It may be configured to include a high frequency resonator 230 that resonates in parallel at a high frequency.

The dual-frequency AC signal generated by the AC signal generator 600 passes through the transformer 210 of the magnetic field generator 200.

The coil 204 and the capacitor 222 of the low-frequency resonator 220 form series resonance by the low-frequency AC signal, that is, the low-frequency signal in the dual-frequency AC signal passing through the transformer 210. In addition, the coil 204 and the capacitor 232 of the high frequency resonator 230 form parallel resonance by the high frequency AC signal, that is, the high frequency signal, from the dual frequency AC signal passing through the transformer 210.

Then, the coil 204 generates a dual-frequency magnetic field by the dual-frequency AC signal.

The power loss detection unit 610 receives the AC signal generated by the AC signal generator 600 to detect power loss and outputs the detection signal to the control/determination unit 640 .

When the pouch-type secondary battery cell 100 is not in a position where the quality can be inspected, the magnetic field generated by the magnetic field generating means 200 is not lost, and the power loss detection unit 610 does not detect power loss. will not be able to Then, the control/determination unit 640 may determine that the pouch type secondary battery cell 100 is not in a position where the quality can be inspected based on the detection signal of the power loss detection unit 610 .

When the pouch-type secondary battery cell 100 is in a position where the quality can be inspected, the dual-frequency magnetic field generated by the magnetic field generating means 200 is induced to the pouch-type secondary battery cell 100 and the pouch A dual frequency induced current flows through the secondary battery cell 100 . The power loss detection unit 610 detects power loss as the magnetic field is induced to the pouch-type secondary battery cell 100 .

Then, the control/determination unit 640 may determine that the pouch type secondary battery cell 100 is in a position where the quality can be inspected based on the detection signal of the power loss detection unit 610 .

In this state, the plurality of induced current detection sensors 300 generate dual frequency signals flowing from a plurality of locations of the pouch-type secondary battery cell 100 to the pouch-type secondary battery cell 100 of the pouch-type secondary battery cell 100. Each of the induced currents is detected, and signals of the detected dual-frequency induced currents are output to each of the plurality of signal processors 620 .

Each of the plurality of signal detectors 620 may include a low frequency detection filter 622 and a high frequency detection filter 624 as shown in FIG. 9 .

Among the dual frequency induced current signals detected by each of the plurality of induced current detection sensors 300, the low frequency induced current signal is detected by the low frequency detection filter 622 of each of the plurality of signal processors 620 and controlled/determined. It is input to unit 640. In addition, the high frequency induced current signal in the dual frequency induced current signal detected by each of the plurality of induced current detection sensors 300 is detected by the high frequency detection filter 624 of each of the plurality of signal processors 620 and controlled/controlled. It is input to the determination unit 640.

Then, the control/determination unit 640 converts the low-frequency induced current signal and the high-frequency induced current signal input from each of the plurality of signal processing units 620 to the value of the determination reference range previously stored in the memory 630. , and according to the comparison result, whether or not the pouch type secondary battery cell 100 is defective is determined to generate a determination signal.

10 is a signal flow diagram showing a quality inspection method according to the present invention. Referring to FIG. 10, under the control of the control/determination unit 640, the AC signal generator 600 generates a dual-frequency AC signal, and the generated dual-frequency AC signal is sent to the magnetic field generating means 200. output (S1000).

Then, the magnetic field generating means 200 generates a dual-frequency magnetic field according to the dual-frequency AC signal, and the generated dual-frequency magnetic field is induced to the pouch-type secondary battery cell 100, and the pouch-type secondary battery cell 100 ), the double frequency induced current flows.

In this state, in the power loss detection unit 610, the AC signal generator 600 inputs the dual frequency AC signal to detect power loss, and the control/determination unit 640 detects the power loss detection signal. Enter (S1010).

In addition, the control/determination unit 640 sends an induced current of sufficient strength to the starting position at which the pouch-type secondary battery cell 100 can inspect the quality, that is, the pouch-type secondary battery cell 100, as a power loss detection signal. It is determined whether or not to flow (S1020).

The control/determination unit 640, when it is determined that the pouch-type secondary battery cell 100 is located at the starting position at which the quality can be inspected, the dual frequency induced current from the plurality of signal processing units 620 A signal is input (S1030).

Then, the control/determination unit 640 compares the dual frequency induced current signal with a value in the judgment standard range (S1040), and uses the comparison result to determine whether the pouch-type secondary battery cell 100 is good or bad. Determine (S1050).

In the above, the present invention has been described in detail through representative embodiments, but those skilled in the art can make various modifications to the above-described embodiments without departing from the scope of the present invention. All or part of each of the embodiments may be selectively combined to be configured.

Therefore, the scope of the present invention should not be limited to the described embodiments and should not be defined, and should be defined by not only the claims to be described later, but also those equivalent to these claims.

100: pouch type secondary battery cell 110: positive electrode plate
112, 122: bent portion 120: negative electrode plate
130: separator 140: terminal
150, 160: electrode 200: magnetic field generating means
202: core 204: coil
210: transformer 220: series resonator
230: parallel resonator 300; 300a∼300d: induced current detection sensor
302, 304: cracks 400: shielding means
600: AC signal generator 610: power loss detector
620: a plurality of signal processing units 622: low frequency detection filter
624: high frequency detection filter 630: memory
640: control/determination unit

Claims (8)

an AC signal generator for generating an AC signal;
a magnetic field generator for generating a magnetic field in response to the AC signal and causing an induced current to flow through the pouch-type secondary battery cell;
At least one induced current detection sensor for detecting a signal of the induced current flowing into the pouch type secondary battery cell; and
A pouch-type secondary battery comprising a control/determination unit that compares the signal of the induced current detected by the induced current detection sensor with a value of a judgment range stored in advance and determines the quality of the pouch-type secondary battery cell according to the comparison result. Battery cell quality inspection device.
According to claim 1,
Further comprising a power loss detection unit for detecting power loss of the AC signal generated by the AC signal generator,
The control/determination unit determines whether or not the at least one induced current detection sensor is positioned at a starting position where the at least one induced current detection sensor starts detecting an induced current from a pouch-type secondary battery cell based on a detection signal of the power loss detection unit. A quality inspection device for pouch-type secondary battery cells.

The method of claim 1, wherein the magnetic field generating means,
a transformer for transmitting the AC current generated by the AC signal generating unit;
a series resonator that resonates in series with the low frequency of the alternating current so that a coil generates a magnetic field; and
A quality inspection device for a pouch-type secondary battery cell, comprising: a parallel resonator unit that resonates in parallel with the high frequency of the alternating current so that the coil generates a magnetic field.
According to claim 1,
It further includes; one or more signal processors outputting signals of the induced current detected by the induced current detection sensor to the control/determination unit;
The AC signal generator,
Generates an AC signal having a dual frequency of a low frequency and a high frequency,
The signal processing unit,
a low frequency detection filter for detecting the low frequency alternating current signal and outputting it to the control/determination unit; and
A high-frequency detection filter for detecting the high-frequency alternating current signal and outputting the signal to the control/determination unit; quality inspection device for a pouch-type secondary battery cell comprising a.
According to claim 1,
When the pouch-type secondary battery cell is located at the starting position, the one or more induced current detection sensors move and scan the pouch-type secondary battery cell to detect a signal of induced current. quality inspection device.
According to claim 1,
The pouch-type secondary battery cell and the one or more induced current detection sensors are fixed, and the pouch-type secondary battery cell moves so that the signal of the induced current is detected by being scanned by the one or more induced current detection sensors. A quality inspection device for a pouch-type secondary battery cell.
The method of claim 1, between the magnetic field generating means and the induced current detection sensor,
Quality inspection device for a pouch-type secondary battery cell, characterized in that it further comprises; shielding means for shielding the magnetic field of the magnetic field generating means.
generating an AC signal by an AC signal generating unit and generating a magnetic field by a magnetic field generating unit according to the generated AC signal so that an induced current flows through the pouch-type secondary battery cell;
detecting a signal of an induced current flowing to the pouch-type secondary battery cell by an induced current detection sensor; and
A method for inspecting the quality of a pouch-type secondary battery cell comprising the step of comparing the signal of the induced current detected by the induced current detection sensor with a value of a judgment reference range by a control/determination unit to determine the quality of the pouch-type secondary battery cell. .

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