KR20230057099A - Battery cell inspection device - Google Patents

Abstract

According to an embodiment of the present invention, a battery cell inspection device is a device for inspecting a sealing unit in which an outer circumference of a battery case is sealed in a battery cell. The device comprises: an emitting unit that irradiates ultrasonic waves to the sealing unit; a receiving unit that receives the ultrasonic waves transmitted through the sealing unit; and a leak prevention unit located to be adjacent to an end of the sealing unit.

Description

Battery cell inspection device {BATTERY CELL INSPECTION DEVICE}

The present invention relates to a battery cell inspection device, and more particularly, to a battery cell inspection device that performs a non-destructive test on a sealing portion of a battery cell.

As technology development and demand for mobile devices increase, demand for secondary batteries as an energy source is rapidly increasing. In particular, secondary batteries are of great interest as energy sources for power devices such as electric bicycles, electric vehicles, and hybrid electric vehicles as well as mobile devices such as mobile phones, digital cameras, laptops, and wearable devices.

Depending on the shape of the battery case, these secondary batteries are classified into cylindrical batteries and prismatic batteries in which the electrode assembly is embedded in a cylindrical or prismatic metal can, and pouch-type batteries in which the electrode assembly is embedded in a pouch-type case made of an aluminum laminate sheet. do. Here, the electrode assembly embedded in the battery case is a power generating device capable of charging and discharging, consisting of a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode. It is classified into a jelly-roll type wound with a separator interposed and a stack type in which a plurality of positive and negative electrodes are sequentially stacked in a state in which a separator is interposed.

Among these, in particular, the pouch-type battery having a structure in which a stacked or stacked/folding type electrode assembly is embedded in a pouch-type battery case of an aluminum laminate sheet is gradually being used due to low manufacturing cost, small weight, and easy deformation shape. It is increasing.

In particular, in the case of a pouch battery cell, in a state where the electrode assembly is built into a pouch-type battery case, the outer periphery of the battery case is sealed by thermal fusion or press fusion. However, despite this sealing process, there is a problem that the sealing state of the battery cell may be defective, and the electrolyte solution or gas inside the battery cell is discharged to the outside through the weak sealing part. However, a conventional battery cell inspection apparatus for checking whether a battery cell is sealed generally has a problem in that the inspection efficiency is low and the inspection process is complicated because the battery is physically destroyed and inspected.

Accordingly, there is a growing need to develop a battery cell inspection device that increases inspection efficiency and relatively simplifies the inspection process while ensuring the safety of the battery cell by checking whether or not the battery cell is sealed.

An object to be solved by the present invention is to provide a battery cell inspection device that performs a non-destructive test on the sealing portion of the battery cell.

The problem to be solved by the present invention is not limited to the above-mentioned problems, and problems not mentioned will be clearly understood by those skilled in the art from this specification and the accompanying drawings. .

An apparatus for inspecting a battery cell according to an embodiment of the present invention is a device for inspecting a sealing portion in which an outer periphery of a battery case is sealed in a battery cell, comprising: an emission unit for irradiating ultrasonic waves to the sealing portion; a receiver configured to receive ultrasonic waves transmitted through the sealing unit; and a leakage preventing part positioned adjacent to an end of the sealing part.

The sealing portion may be a portion through which an electrode lead protrudes outward from the battery case.

The sealing part may include a surface sealing part contacting the upper or lower surface of the electrode lead and a stepped sealing part contacting the side surface of the electrode lead.

The emission unit may irradiate ultrasonic waves to the sealing unit along a direction perpendicular to a protruding direction of the electrode lead.

The emission unit may irradiate the sealing unit with ultrasonic waves at least twice.

The leakage preventing part may extend from an end of the sealing part toward an end of the electrode lead.

The electrode lead may be positioned between the leakage prevention part and the emission part.

The leakage preventing part may be a pad made of at least one of silicon, plastic, metal, and rubber.

A frequency of the ultrasonic wave irradiated from the emitter may be 650 kHz or more and 950 kHz or less.

A pitch of ultrasonic waves emitted from the emission unit may be 0.01 mm or more and 0.5 mm or less.

A scan speed of the emission unit may be 10 mm/s or more and 50 mm/s or less.

According to embodiments, the present invention is a battery cell inspection apparatus including an emitter for irradiating ultrasonic waves on the sealing portion of a battery cell and a receiver for receiving ultrasonic waves transmitted through the sealing portion, which is non-destructive to the sealing portion of the battery cell. inspection can be performed.

The effect of the present invention is not limited to the above-mentioned effects, and effects not mentioned will be clearly understood by those skilled in the art from this specification and the accompanying drawings.

1 is a view showing a battery cell inspection apparatus according to an embodiment of the present invention.
FIG. 2 is a view showing a battery cell as an inspection object of the inspection device of FIG. 1 .
3 is a cross-sectional view taken along the A-A' axis of FIG. 2;
4 is a view showing a battery cell inspection device according to a comparative example.
5 to 8 are views showing experimental results according to Experimental Example 1.
9 is a view showing experimental results according to Experimental Example 2;

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. This invention may be embodied in many different forms and is not limited to the embodiments set forth herein.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

In addition, since the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, the present invention is not necessarily limited to the shown bar. In the drawings, the thickness is shown enlarged to clearly express the various layers and regions. And in the drawings, for convenience of explanation, the thicknesses of some layers and regions are exaggerated.

In addition, throughout the specification, when a part "includes" a certain component, it means that it may further include other components without excluding other components unless otherwise stated.

In addition, throughout the specification, when it is referred to as "planar image", it means when the target part is viewed from above, and when it is referred to as "cross-sectional image", it means when a cross section of the target part cut vertically is viewed from the side.

Hereinafter, a battery cell inspection apparatus according to an embodiment of the present invention will be described.

1 is a view showing a battery cell inspection apparatus according to an embodiment of the present invention. FIG. 2 is a view showing a battery cell as an inspection object of the inspection device of FIG. 1 . 3 is a cross-sectional view taken along the A-A′ axis of FIG. 2 .

1 and 2, the battery cell inspection apparatus according to an embodiment of the present invention is a device for inspecting the sealing portion 250 in which the outer periphery of the battery case 200 is sealed in the battery cell 100. , the emission unit 1100 for irradiating ultrasonic waves to the sealing unit 250; a receiver 1200 for receiving ultrasonic waves transmitted through the sealing unit 250; and a leak prevention unit 1300 positioned adjacent to an end of the sealing unit 250 .

The emitter 1100 and the receiver 1200 may be disposed at opposite positions with the battery cell 100 interposed therebetween. More specifically, the emission unit 1100 and the reception unit 1200 may be disposed at opposite positions with the sealing unit 250 of the battery cell 100 interposed therebetween.

In addition, in the battery cell inspection device according to the present embodiment, the emitter 1100 may irradiate ultrasonic waves toward the seal 250, and the receiver 1200 may receive ultrasonic waves transmitted through the seal 250. . That is, the receiving unit 1200 may determine whether the sealing unit 250 is defective based on the waveform of the ultrasonic waves transmitted through the sealing unit 250 . In other words, the transmittance of ultrasonic waves received by the receiver 1200 may vary depending on the difference in density inside the sealing unit 250, and based on this, it is possible to determine whether or not the sealing unit 250 is defective.

For example, the battery cell inspection device according to the present embodiment may be an aerial ultrasonic device using air located between the emitter 1100 and the receiver 1200 as a coupling agent.

Accordingly, the battery cell inspection apparatus according to the present embodiment may non-destructively test the sealing unit 250 through the emission unit 1100 and the reception unit 1200 .

2 and 3, the battery cell 100, which is an inspection object of the battery cell inspection apparatus according to the present embodiment, has a structure in which the electrode assembly 110 is mounted in the housing 210 and the outer periphery is sealed. a battery case 200 including a sealing part 250; and an electrode lead 300 electrically connected to the electrode tab 115 included in the electrode assembly 110 and protruding outward of the battery case 200 via the sealing portion 250 .

The battery case 200 may be a laminate sheet including a resin layer and a metal layer. More specifically, the battery case 200 is made of a laminate sheet, and may be composed of an outer resin layer forming the outermost shell, a barrier metal layer to prevent penetration of materials, and an inner resin layer for sealing.

The electrode assembly 110 may have a structure of a jelly-roll type (winding type), a stack type (lamination type), or a combination type (stack/folding type). More specifically, the electrode assembly 110 may include an anode, a cathode, and a separator disposed between them.

The electrode lead 300 is electrically connected to an electrode tab (not shown) included in the electrode assembly 110 and protrudes outward from the battery case 200 via the sealing portion 250 . In addition, the lead film 400 is located at a portion corresponding to the sealing portion 250 in at least one of the upper and lower portions of the electrode lead 300 .

Accordingly, the lead film 400 prevents a short circuit from occurring in the electrode lead 300 during thermal fusion or press fusion together with the sealing portion 250, and sealability between the sealing portion 250 and the electrode lead 300. can improve

Referring to FIGS. 2 and 3 , in the battery cell inspection device according to the present embodiment, the sealing portion 250 through which the emission portion 1100 irradiates ultrasonic waves is an electrode lead protruding outward from the battery case 200 . 300 may be a part passing through. In other words, the inspection object of the battery cell inspection apparatus according to the present embodiment may be the sealing part 250 through which the electrode lead 300 passes.

More specifically, referring to FIG. 3 , as a test object of the battery cell inspection apparatus according to the present embodiment, the sealing part 250 is a surface sealing part 300a in contact with the upper or lower surface of the electrode lead 300 and the electrode lead. It may include a stepped sealing portion (400a) in contact with the side surface of (300).

Here, the surface sealing portion 300a may refer to a portion sealed at a position corresponding to the surface of the electrode lead 300 . For example, a leak may occur in the surface sealing part 300a due to foreign substances such as pouch scraps.

In addition, the stepped sealing portion 400a may refer to a portion sealed at a position corresponding to the stepped region of the end of the electrode lead 300 . For example, a leak portion may occur in the stepped sealing portion 400a due to misalignment between the upper mold and the lower mold used to form the sealing portion 250 .

In addition, the emission unit 1100 may irradiate the sealing unit 250 with ultrasonic waves along a direction perpendicular to the protruding direction of the electrode lead 300 . In other words, the emission unit 1100 may irradiate ultrasonic waves along a direction perpendicular to the protruding direction of the electrode lead 300 to the sealing unit 250 through which the electrode lead 300 passes.

In this case, the emission unit 1100 may irradiate the sealing unit 250 with ultrasonic waves at least twice. For example, the emission unit 1100 may respectively irradiate ultrasonic waves to different locations based on the center of the sealing unit 250 .

Accordingly, the battery cell inspection apparatus according to the present embodiment can further improve the accuracy of the inspection result of the sealing part 250 .

In addition, the frequency of ultrasonic waves emitted from the emitter 1100 may be 650 kHz or more and 950 kHz or less. More specifically, the frequency of ultrasonic waves emitted from the emitter 1100 may be 675 kHz or more and 925 kHz or less. For example, the frequency of ultrasonic waves emitted from the emitter 1100 may be 700 kHz or more and 900 kHz or less.

Accordingly, in the battery cell inspection device according to the present embodiment, the emission unit 1100 emits ultrasonic waves having a frequency in the above-described range, so that both the ultrasonic transmittance and resolution of the sealing unit 250 may be excellent, Detection performance of whether or not the sealing unit 250 is defective may be improved.

On the other hand, when ultrasonic waves having a frequency that is too small than the above-described range are irradiated from the emission unit 1100, the resolution may be deteriorated and the detection performance of the sealing unit 250 may be greatly deteriorated. In addition, when ultrasonic waves having a frequency exceeding the above-mentioned range are irradiated from the emission unit 1100, the ultrasonic transmittance of the sealing unit 250 may decrease, and it is difficult to detect whether or not the sealing unit 250 is defective. there is

In addition, a pitch of ultrasonic waves irradiated from the emitter 1100 may be 0.01 mm or more and 0.5 mm or less. More specifically, a pitch of ultrasonic waves emitted from the emission unit 1100 may be 0.02 mm or more and 0.3 mm or less. A pitch of ultrasonic waves emitted from the emitter 1100 may be 0.05 mm or more and 0.15 mm or less.

Accordingly, in the battery cell inspection device according to the present embodiment, the emission unit 1100 is irradiated with ultrasonic waves having a pitch in the above-described range, so that the inspection time is efficient and the resolution of the sealing unit 250 is excellent. And, the detection performance of whether or not the sealing part 250 is defective can be improved.

In contrast, when ultrasonic waves having an excessively smaller pitch than the above range are irradiated from the emission unit 1100, the inspection time may be very long. In addition, when ultrasonic waves having an excessively greater pitch than the above range are irradiated from the emission unit 1100, the resolution of the sealing unit 250 may decrease, and it is difficult to detect whether or not the sealing unit 250 is defective. there is

Also, the scan speed of the emission unit 1100 may be 10 mm/s or more and 50 mm/s or less. More specifically, the scan speed of the emission unit 1100 may be 15 mm/s or more and 45 mm/s or less. For example, the scan speed of the emission unit 1100 may be 20 mm/s or more and 40 mm/s or less.

Accordingly, in the battery cell inspection apparatus according to the present embodiment, the scan speed of the emission unit 1100 is within the above-described range, so that the inspection time is efficient, the resolution of the sealing unit 250 can be excellent, and the sealing unit 250 can have excellent resolution. Detection performance of whether the unit 250 is defective may be improved.

On the other hand, if the scanning speed of the emission unit 1100 is too slow than the above range, the inspection time may be very long. In addition, when the scan speed of the emission unit 1100 is excessively faster than the above-described range, the resolution of the sealing unit 250 may decrease, and it is difficult to detect whether or not the sealing unit 250 is defective.

Also, referring to FIGS. 1 and 2 , the leakage preventing part 1300 may be positioned adjacent to an end of the sealing part 250 . More specifically, the leakage preventing part 1300 may extend from the end of the sealing part 250 toward the end of the electrode lead 300 . Here, the sealing part 250 may be a part through which the electrode lead 300 passes. In addition, the electrode lead 300 may be positioned between the leakage prevention unit 1300 and the emission unit 1100 .

For example, the leakage prevention unit 1300 may be a pad made of at least one of silicon, plastic, metal, and rubber. However, the material of the leakage preventing unit 1300 is not limited thereto, and any material capable of preventing leakage of ultrasonic waves into the air may be included in the present embodiment.

Accordingly, in the battery cell inspection apparatus according to the present embodiment, the leakage prevention unit 1300 is located adjacent to the end of the sealing unit 250, and the ultrasonic wave is irradiated toward the sealing unit 250 from the emission unit 1100. can be prevented from leaking into the air, and inspection performance can be further improved while the inspection area is expanded.

4 is a view showing a battery cell inspection device according to a comparative example.

Referring to FIG. 4 , the battery cell inspection apparatus according to the comparative example includes a discharge unit 11 and a receiver 12, and unlike the battery cell inspection apparatus of FIG. don't

Accordingly, in the case of the battery cell inspection device according to the comparative example, unlike the battery cell inspection device of FIG. 1, some of the ultrasonic waves irradiated from the emitter 11 may leak into the air, so that the inspection area is reduced and the inspection accuracy is reduced. There is a problem of deterioration.

Hereinafter, the content of the present invention will be described through more specific examples, but the following examples are intended to illustrate the present invention by way of example, and the scope of the present invention is not limited thereto.

<Example>

A battery cell inspection device including an emitter and a receiver was prepared. Here, the emitter irradiated the test object with ultrasonic waves having a frequency of 800 kHz, a pitch of 0.1 mm, and a speed of 30 mm/s.

<Comparative example>

The same battery cell inspection device as in the embodiment was prepared, except that the emitter irradiated the test object with ultrasonic waves having a frequency of 400 kHz.

<Experimental Example 1 - Inspection results according to Examples>

With respect to the normal battery cell and the three defective battery cells, defects were measured twice using the battery cell inspection device of Example centering on the portion where the electrode lead was located among the sealing parts of the battery cell. The inspection results for the normal battery cells are shown in FIG. 5, and the inspection results for the three defective battery cells are shown in FIGS. 6 to 8, respectively.

Referring to FIG. 5 , as a result of inspecting the portion where the electrode lead is located among the sealing parts of the normal battery cell with the battery cell inspection device of the embodiment, it can be confirmed that a peak appears constantly at a position corresponding to the electrode lead.

On the other hand, referring to FIGS. 6 to 8 , as a result of inspecting the portion where the electrode lead is located among the sealing parts of the three defective battery cells with the battery cell inspection device of the embodiment, the peak is uneven at the position corresponding to the electrode lead. You can see what appears.

More specifically, in the case of the defective battery cell of FIG. 6 , it can be confirmed that peaks appear non-uniformly at positions corresponding to both ends of the electrode leads. That is, in the case of the defective battery cell of FIG. 6 , it can be confirmed that a leak has occurred at a position corresponding to the stepped portion of the electrode lead among the sealing parts.

In addition, in the case of the defective battery cell of FIG. 7 , it can be confirmed that peaks appear non-uniformly at specific positions among parts corresponding to the center of the electrode lead. That is, in the case of the defective battery cell of FIG. 7 , it can be confirmed that a leak has occurred at a position corresponding to the surface of the electrode lead among the sealing parts.

In addition, in the case of the defective battery cell of FIG. 8 , it can be seen that peaks are generally non-uniformly displayed in a portion corresponding to the center of the electrode lead. That is, in the case of the defective battery cell of FIG. 8 , it can be confirmed that a foreign material is inserted at a position corresponding to the surface of the electrode lead among the sealing parts.

In this way, when inspecting the sealing part of the battery cell with the battery cell inspection device of the embodiment, it is possible to distinguish between normal and defective battery cells, and also check the defective type of the defective battery cell.

<Test results according to Experimental Example 2-Comparative Example>

Among the sealing parts of the battery cell, defects were measured centering on the portion where the electrode lead was located, using the battery cell inspection device of the comparative example, and the results are shown in FIG. 9 .

Referring to FIG. 9 , as a result of inspecting the portion where the electrode lead is located among the sealing parts of the battery cell with the battery cell inspection device of the comparative example, it can be confirmed that the peak at the position corresponding to the electrode lead is not accurately measured.

As such, when inspecting the sealing portion of the battery cell with the battery cell inspection device of the comparative example, it can be confirmed that it is difficult to distinguish between a normal battery cell and a defective battery cell.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also provided. It falls within the scope of the right of invention.

100: battery cell
110: electrode assembly
115: electrode tab
200: battery case
210: storage unit
250: sealing part
300: electrode lead
300a: surface sealing part
400: lead film
400a: step sealing part
1100: emission unit
1200: receiver
1300: leak prevention unit

Claims (11)

A device for inspecting a sealing part in which the outer periphery of a battery case is sealed in a battery cell,
an emission unit irradiating ultrasonic waves to the sealing unit;
a receiver configured to receive ultrasonic waves transmitted through the sealing unit; and
Battery cell inspection device including a leakage prevention portion positioned adjacent to the end of the sealing portion. In paragraph 1,
The sealing portion is a battery cell inspection device that is a portion through which an electrode lead protrudes outwardly of the battery case. In paragraph 2,
The sealing part includes a surface sealing part in contact with the upper or lower surface of the electrode lead and a step sealing part in contact with the side surface of the electrode lead. In paragraph 3,
The battery cell inspection device for irradiating ultrasonic waves along the direction perpendicular to the protruding direction of the electrode lead with respect to the sealing portion. In paragraph 3,
The battery cell inspection device for irradiating the emission unit with ultrasonic waves at least twice or more to the sealing unit. In paragraph 2,
The battery cell inspection device wherein the leakage preventing portion extends from an end of the sealing portion toward an end of the electrode lead. In paragraph 6,
The electrode lead is a battery cell inspection device positioned between the leakage preventing portion and the emission portion. In paragraph 6,
The battery cell inspection device wherein the leakage preventing portion is a pad made of at least one of silicon, plastic, metal, and rubber. In paragraph 1,
The frequency of the ultrasonic waves irradiated from the emitter is a battery cell inspection device of 650 kHz or more to 950 kHz or less. In paragraph 8,
A battery cell inspection device in which the pitch of ultrasonic waves irradiated from the emitter is 0.01 mm or more to 0.5 mm or less. In paragraph 1,
Battery cell inspection device wherein the scan speed of the emitter is 10 mm / s or more to 50 mm / s or less.

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