KR101305255B1 - Methode and Device for Inspection of Intensity of Ultrasonic Welding - Google Patents

Abstract

The present invention provides a method for inspecting whether an ultrasonic welding part is defective, comprising: (a) photographing a welding part in contact with an anvil of an ultrasonic welding device; (b) measuring an area of a welded portion in the photographed image; (c) comparing the measured weld area with a reference area to determine a size; And (d) classifying the measured weld area as defective if it is smaller than the reference area, and classifying it as good when the measured area is equal to or larger than the reference area. do.

Description

Method and apparatus for strength testing of ultrasonic welding {Methode and Device for Inspection of Intensity of Ultrasonic Welding}

The present invention provides a method for inspecting whether an ultrasonic welding part is defective, the method comprising: (a) photographing a welding part in contact with an anvil of an ultrasonic welding device; (b) measuring an area of a welded portion in the photographed image; (c) comparing the measured weld area with a reference area to determine a size; And (d) classifying the measured weld area as less than the reference area, and classifying the defect as bad, and conversely, classifying the weld area as good or greater than the reference area.

As the development and demand for mobile devices increases, the demand for secondary batteries as energy sources is rapidly increasing. Among them, lithium secondary batteries exhibiting high energy density and operating potential, long cycle life, and low self discharge rate. Batteries have been commercialized and widely used.

In recent years, there has been a growing interest in environmental issues, and as a result, electric vehicles (EVs) and hybrid electric vehicles (HEVs), which can replace fossil-fueled vehicles such as gasoline vehicles and diesel vehicles, And the like. Although a nickel metal hydride (Ni-MH) secondary battery is mainly used as a power source for such an electric vehicle (EV) and a hybrid electric vehicle (HEV), a lithium secondary battery having a high energy density, a high discharge voltage, Research is being actively carried out, and some are commercialized.

The lithium secondary battery has a structure in which a non-aqueous electrolyte containing a lithium salt is impregnated in an electrode assembly having a porous separator interposed between a positive electrode and a negative electrode coated with an active material on a current collector.

The electrode assembly of the positive electrode / separation membrane / cathode structure constituting the secondary battery is largely jelly-roll type (wound type) and stack type (stacked type), and a stack / folding type of the jelly-roll type and stack type mixed according to its structure. Are divided into types.

The electrode assembly includes an electrode tab for connecting to an external terminal at each electrode. These electrode tabs are joined by welding with electrode leads for external terminal connection in the assembly process.

At this time, the welding is mainly used for ultrasonic welding. This is because, when resistance welding, laser welding, or the like is used, the performance of the battery may be degraded due to the excessive application of energy to the electrode assembly.

In this welding, when the welding strength between the electrode tab and the electrode lead is too weak, the welding part may be separated in the process of combining the battery module or the battery pack using the battery cell. When the welding region between the tab and the lead is separated from the battery module or battery pack manufactured by connecting a plurality of battery cells in series or in parallel, the entire battery pack may not function and is considered a serious defect.

In order to confirm whether the ultrasonic welding is defective, the battery cell samples were extracted to determine whether the defect was defective through a fracture test such as a shear test.

However, in the case described above, there is a problem in that a battery cell that is not selected as a sample cannot be guaranteed as to be defective because it cannot be inspected.

Therefore, there is a great need for a method capable of fully inspecting whether the ultrasonic welding site is defective, which can fundamentally solve these problems.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems of the prior art and the technical problems required from the past.

After extensive research and various experiments, the inventors of the present application have developed a method capable of conducting a full inspection of defects in ultrasonic welding in a specific manner as described later.

Specifically, the inspection method according to the present invention, as a method for inspecting whether the ultrasonic welding portion is defective,

(a) photographing a welding portion in contact with the anvil of the ultrasonic welding device;

(b) measuring an area of a welded portion in the photographed image;

(c) comparing the measured weld area with a reference area to determine a size; And

(d) classifying as bad when the measured weld area is smaller than the reference area, and classifying as good when the same or larger than the reference area;

.

Ultrasonic welding is a method of welding various nonferrous metals by using high frequency vibration. The apparatus for ultrasonic welding includes an ultrasonic controller, a vibrator, a horn, anvil, a fixing device, and a cylinder. The controller converts AC power into high frequency omnipotence (usually 20 kHz to 40 kHz), and converts it into high frequency mechanical vibration energy while passing through the vibrator. The mechanical vibration energy thus converted is transmitted to the horn while maintaining the amplitude of the oscillation while increasing, decreasing or unchanging the oscillator, and the horn welds the component between the horn and the anvil in the horizontal direction. The welded parts are welded under horizontal friction and vertical pressure.

Specifically, the high frequency mechanical vibrations are transmitted to two metal material surfaces so that the two metal surfaces rub against each other in pressurized state, and valence surface contact and fusion with each other result in fixed fusion between molecules. Metal bonding is realized.

As described above, in the inspection of the failure of the ultrasonic welding, it is impossible to perform the entire inspection because it was determined by the failure test such as shear test in the prior art, and only the welding failure test for the sample was carried out by extracting the sample. The reliability of the whole product could not be guaranteed.

The present inventors have found that the welded area and the weld strength of the anvil face have a positive correlation, and have completed the present invention. That is, the larger the welded area of the anvil surface, the higher the welding strength, and thus, a total inspection of all battery cells is possible through a non-destructive test that measures the welded area of the anvil surface instead of a fracture test.

In general, the anvil may have irregularities on the surface for the purpose of welding. Therefore, the welded portion of the anvil face may consist of several parts which are not continuous. In this case, it is preferable to add and measure a large number of weld area areas because the reliability can be improved.

In one preferred example, the welding portion may be an ultrasonic welding portion of the electrode lead to the electrode tabs of the battery cell.

The electrode tabs are portions protruding from the electrode plate (current collector) to which the electrode mixture containing the active material and the like are coated, and thus are easily affected by high temperature, resistance, sparks, and the like. Therefore, in the case of welding by a general method, the electrode active material is affected by heat or sparks, which is not preferable. Ultrasonic welding, on the other hand, does not need to dissolve the weld material, does not change the metal properties, has good conductivity after welding and has a low coefficient of resistance, no special requirements on the weld metal surface, and no need to remove oxidation and electroplating. It is particularly preferable for welding electrode leads to electrode tabs since no flame, smoke, or the like occurs during welding.

In the step (b), the method of measuring the area of the welded part may vary, but one preferable example may include measuring the pixel unit of the photographed image. By recognizing the number of pixels corresponding to the area occupied by the welded portion in the photographed image, automation is possible and uniform measurement criteria can be applied. Such imaging may be performed by an image camera, for example.

The reference area of step (c) may be based on an area that may have a strength such that the welded site does not break in the whole process and actual use, preferably, based on an area having a weld breaking strength of 10 kgf. . In general, when the weld breaking strength is less than 10 kgf, it is not preferable because the welding site may be broken during the process of modularizing the battery cell. For the process reliability and the reliability of the product, it is more preferable that the reference area has an area of 40 kgf of weld breaking strength.

The setting of the reference area according to the weld breaking strength may vary depending on the material, thickness, and the like of the members to be welded. Therefore, those skilled in the art will have no difficulty in setting a reference area according to the weld breaking strength in a state in which materials, sizes, and the like of the members are specified.

The defect inspection of the ultrasonic welding portion may be a non-destructive total inspection. As described above, when the sample is extracted and inspected, the quality of the ultrasonic welding that is not inspected cannot be guaranteed, and in the case of the fracture inspection, the full inspection cannot be performed due to its characteristics. Therefore, the quality of all ultrasonic welding can be guaranteed through non-destructive inspection.

The present invention also provides a device for inspecting the defect of the ultrasonic welding site,

(i) a photographing unit for photographing a welding portion in contact with the anvil (anvil) of the ultrasonic welding apparatus;

(ii) an area measuring unit measuring an area of a welded portion in the image photographed by the photographing unit;

(iii) a reference area storage for storing information about the reference area; And

(iv) a control unit for classifying the inspected object as good or defective by comparing the measured welding area from the area measuring unit with the reference area of the reference area storing unit;

It provides an ultrasonic welding strength inspection apparatus comprising a.

In the ultrasonic welding strength inspection device, the photographing unit may be an image camera. In the image photographed using the image camera, the welded portion may be distinguished by a difference in color or contrast.

In the case of the above-described image camera, the higher the resolution, the narrower the area per pixel. However, the higher the resolution, the higher the price of the device, and the greater the amount of information to be processed. Therefore, an image camera in the range of 500,000 to 1.5 million pixels may be preferable.

The area measuring unit, the reference area storage unit, the control unit, etc. may be implemented as a separate device, for example, may be implemented together in a device such as a personal computer.

The present invention also provides a lithium secondary battery which is determined to be excellent with respect to the ultrasonic welding site in the above method. The lithium secondary battery is composed of an electrode assembly consisting of a positive electrode, a separator, a negative electrode and a lithium salt-containing nonaqueous electrolyte.

When the positive electrode is manufactured by, for example, applying a mixture of a positive electrode active material, a conductive material, and a binder onto a positive electrode current collector, and then drying and pressing the positive electrode, a filler may be further added to the mixture, if necessary. The whole is usually made to a thickness of 3 to 500 μm. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. Examples of the positive electrode current collector include stainless steel, aluminum, nickel, titanium, sintered carbon, aluminum or stainless steel A surface treated with carbon, nickel, titanium, silver or the like may be used. The current collector may have fine irregularities on the surface thereof to increase the adhesive force of the cathode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric are possible.

The cathode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with one or more transition metals; Li _{1 + x} Mn _2-x O ₄ (Where x is 0 to 0.33), lithium manganese oxides such as LiMnO ₃ , LiMn ₂ O ₃ and LiMnO ₂ ; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ and Cu ₂ V ₂ O ₇ ; A Ni-site type lithium nickel oxide expressed by the formula LiNi _1-x M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3); Formula _{LiMn 2-x M x O 2} ( where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 ~ 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni, Cu, or Zn); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ , and the like. However, the present invention is not limited to these.

The conductive material is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture including the cathode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, for example, graphite such as natural graphite or artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskeys such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is a component which assists in bonding of the active material and the conductive material and bonding to the current collector, and is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture containing the cathode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers and the like.

The filler is optionally used as a component for suppressing the expansion of the anode, and is not particularly limited as long as it is a fibrous material without causing a chemical change in the battery. Examples of the filler include olefin polymers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

On the other hand, the negative electrode is manufactured by applying, drying and pressing an anode active material on an anode current collector, and may optionally further include a conductive material, a binder, a filler, and the like as described above.

The negative electrode current collector is generally made to have a thickness of 3 to 500 mu m. Such an anode current collector is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, and examples of the anode current collector include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, a surface of copper or stainless steel A surface treated with carbon, nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used. In addition, like the positive electrode collector, fine unevenness can be formed on the surface to enhance the bonding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams and nonwoven fabrics.

The negative electrode active material may include, for example, carbon such as non-graphitized carbon or graphite carbon; _{Li x Fe 2 O 3 (0≤x≤1} ), Li x WO 2 (0≤x≤1), Sn x Me 1-x Me 'y O z (Me: Mn, Fe, Pb, Ge; Me' : Metal complex oxides such as Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, Halogen, 0 < x &lt; Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO 2, Bi 2 O 3, Bi 2 O 4, and Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

The separation membrane is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 mu m and the thickness is generally 5 to 300 mu m. Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane. The separator film used in the present invention may or may not be the same material as the separator.

The lithium salt-containing nonaqueous electrolyte solution is composed of an electrolyte solution and a lithium salt. As the electrolyte solution, a nonaqueous organic solvent, an organic solid electrolyte, and an inorganic solid electrolyte may be used.

Examples of the non-aqueous organic solvent include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma -Butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane , Acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate Nonionic organic solvents such as tetrahydrofuran derivatives, ethers, methyl pyrophosphate, ethyl propionate and the like can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, A polymer containing an ionic dissociation group and the like may be used.

As the inorganic solid electrolyte, for example, Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO ₄ -LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Nitrides, halides, sulfates, and the like of Li, such as Li ₄ SiO ₄ -LiI-LiOH, Li ₃ PO ₄ -Li ₂ S-SiS ₂ , and the like, may be used.

The lithium salt is a material that is readily soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO 4, LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF _{6, LiSbF 6, LiAlCl 4,} CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide have.

For the purpose of improving the charge / discharge characteristics and the flame retardancy, the electrolytic solution is preferably mixed with an organic solvent such as pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, Benzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, . In some cases, halogen-containing solvents such as carbon tetrachloride and ethylene trifluoride may be further added to impart nonflammability. In order to improve the high-temperature storage characteristics, carbon dioxide gas may be further added. FEC (Fluoro-Ethylene carbonate, PRS (propene sultone), FPC (fluoro-propylene carbonate), and the like.

As a preferable example, the secondary battery may have a breaking strength of 10 kgf or more at the ultrasonic welding site. More preferably, the secondary battery may have a breaking strength of 40 kgf or more at the ultrasonic welding site.

The present invention also provides a medium-large battery module including the lithium secondary battery as a unit cell, and a battery pack including the battery module.

The battery pack may be used as a power source for a variety of medium and large devices that require particularly high rate characteristics and high temperature safety, and may include, for example, a power tool driven by an electric motor; Electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs); Electric motorcycle including E-bike, E-scooter; It may be used as a power source such as an electric golf cart, and may be used for a power storage device, but is not limited thereto.

As described above, the method and apparatus for inspecting whether the ultrasonic welding site is defective according to the present invention can guarantee welding strength for all ultrasonic welding sites through non-destructive inspection.

1 is a perspective view of a pouch-type battery cell;
Fig. 2 is an exploded schematic view of Fig. 1; Fig.
Figure 3 is a photograph of the anvil face welded portion of the sample having a weld strength of 80 kgf or more using the method according to the present invention;
Figure 4 is a photograph of the anvil face welded portion of a sample with a weld strength of less than 10 kgf using the method according to the invention;
5 is a schematic diagram of ultrasonic welding;
It is a schematic diagram of the ultrasonic welding strength test apparatus which concerns on this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

1 is a perspective view schematically illustrating a pouch-type battery cell, and FIG. 2 is an exploded schematic view of FIG. 1.

Referring to these figures, the pouch-shaped battery cell 200 includes an electrode assembly including an anode, a cathode, and a separator disposed between the anode and cathode taps 220 and 230 And two electrode terminals 222 and 232, which are electrically connected to each other, are sealed to be exposed to the outside.

The battery case 100 includes a case body 140 including a concave shaped storage portion 142 on which the electrode assembly 210 can be seated and a lid 150 integrally connected to the body 140 have.

The electrode assembly 210 having the stacked or stacked / folded structure has a plurality of anode tabs 220 and a plurality of anode tabs 230 welded to each other and coupled to the electrode terminals 222 and 232. It is also possible to prevent short-circuiting between the heat sealer and the electrode terminals 222 and 232 when the ingress 144 of the case body 140 and the cover 150 are thermally fused by the heat sealer, The insulating film 240 is attached to the upper and lower surfaces of the electrode terminals 222 and 232 so as to secure the sealing property between the battery case 100 and the battery case 100. [

The case body 140 and the cover 150 are constituted by the outer resin layer 110, the barrier metal layer 120 and the inner resin layer 130. The inner resin layer 130 is formed on the outer surface of the case body 140 And heat and pressure from a heat sealer (not shown) applied to the outer surface of the cover 150.

A sealing portion is formed by thermally fusing the contact portion of the cover 144 with the residue 144 of the case body 140 while the electrode assembly 210 impregnated with the electrolyte is seated in the housing portion 142.

The positive and negative electrode tabs 220 and 230 and the electrode terminals 222 and 232 are welded by ultrasonic welding. By using ultrasonic welding, no heat or spark can be applied to the electrodes, which may not affect battery performance.

FIG. 3 shows a photograph of data of anvil plane welded areas of a sample having a weld strength of 80 kgf or more using the method according to the present invention, and FIG. 4 illustrates anvil plane welded areas of a sample having a weld strength of less than 10 kgf. The photograph is illustrated by data using the method.

Referring to these drawings, it can be seen that the anvil face welded area of the sample having a weld strength of 80 kgf or more is 60% or more wider than the anvil face welded area of the sample having a weld strength of 10 kgf or less.

That is, the weld strength and the area of the anvil face weld site have a positive correlation.

The criterion for determining the failure of the ultrasonic welding may vary depending on the required criteria, but considering the process such as the modularization of the battery cell, the welding strength is preferably 10 kgf or more, more preferably 40 kgf or more.

5 shows a schematic diagram of ultrasonic welding.

Referring to FIG. 5, electrode tabs and electrode leads 331 and 332 connected to an electrode assembly (not shown) are placed on the anvil 320, and the horn 310 is pressurized at a surface corresponding to the anvil 320. Ultrasonic welding is performed while applying. While the horn 310 is pressurized in the vertical direction, it vibrates in the horizontal direction so that the metal surfaces rub against each other and the atoms are in surface contact and fuse with each other to fix. Compared to the vertical movement of the horn 310 to apply pressure in the vertical direction, the anvil 320 is generally fixed to apply pressure to the object to be welded. However, in some cases, the anvil 320 may move to apply pressure with the horn 310.

6 schematically shows an ultrasonic welding strength test apparatus according to the present invention.

Referring to FIG. 6 together with FIG. 5, the ultrasonic welding strength inspection apparatus includes a welding unit 410 for photographing a welding portion in contact with the anvil 320 of the ultrasonic welding device, and an image captured by the imaging unit 410. The area measurement unit 420 which measures the area of the site, the reference area storage unit 430 storing information on the reference area, and the measurement welding area from the area measurement unit 420 are referred to as the reference area storage unit 430. Compared to the reference area of the control unit 440 for classifying the specimen as good or bad.

The photographing unit 410 is preferably a camera capable of capturing an image. The image photographed by the photographing unit 410 may distinguish the welded area by color and / or contrast, and the area is measured by the area measuring unit 420. As one preferable example, the area measuring unit 420 may measure in units of pixels. In this case, the smaller the size of each pixel, that is, the larger the resolution, the more accurate measurement can be performed. For this reason, the photographing unit is preferably high resolution.

The reference area storage unit 430 stores a reference area for determining whether there is a defect, and the reference area may be changed as necessary, for example, in a process. In general, the welding area may be 10 kgf as a reference area in order not to be detached from the secondary battery in a process such as modularization, and preferably, the welding area may be 40 kgf as the reference area.

The controller 440 determines whether the area of the area measuring unit 420 is larger or smaller than the reference area to determine whether there is a defect.

The area measuring unit 420, the reference area storage unit 430, and the control unit 440 may be included in one device, and a computer may be generally used as the device.

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (14)

As a method for inspecting whether an ultrasonic welding part is defective,
(a) photographing a welding portion in contact with the anvil of the ultrasonic welding device;
(b) measuring an area by a difference in color or contrast of the welded portion in the photographed image;
(c) comparing the measured weld area with a reference area to determine a size; And
(d) classifying the measured welding area as defective if it is smaller than the reference area, and conversely, classifying it as good when the welding area is equal to or larger than the reference area;
Lt; / RTI &gt;
The reference area of step (c) is characterized in that the area of the weld breaking strength is 40 kgf. The method of claim 1, wherein the welding portion of the anvil surface is an ultrasonic welding portion of the electrode lead to the electrode tabs of the battery cell. The method of claim 1, wherein in step (b), the area of the welded portion is measured in units of pixels of a captured image. delete delete The method of claim 1, wherein the test is a non-destructive total test. An apparatus for inspecting defects in ultrasonic welding sites,
(i) a photographing unit for photographing a welding portion in contact with the anvil (anvil) of the ultrasonic welding apparatus;
(ii) an area measuring unit measuring an area based on a difference in color or contrast of the welded part in the image photographed by the photographing unit;
(iii) a reference area storage for storing information about the reference area; And
(iv) a control unit for classifying the inspected object as good or defective by comparing the measured welding area from the area measuring unit with the reference area of the reference area storing unit;
Lt; / RTI &gt;
The reference area is an ultrasonic welding strength inspection apparatus, characterized in that the weld breaking strength is 40 kgf. The inspection apparatus according to claim 7, wherein the photographing unit comprises a camera having a resolution of 500,000 to 1.5 million pixels. delete delete delete delete delete delete

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