Short-circuit inspection device and method for secondary battery electrode assemblies

Abstract

To provide a short-circuit inspection device for secondary battery electrode assemblies that applies an enhanced short-circuit inspection method (continuous pulse application) during electrode assembly short-circuit inspection.SOLUTION: A short-circuit inspection device 1 for secondary battery electrode assemblies includes a first plate 10 that presses the bottom surface of an electrode assembly 40 in which a negative electrode and a positive electrode are arranged with a separator membrane in between, a second plate 20 that presses the top surface of the electrode assembly 40 above the first plate 10, and a continuous pulse generator 30 that is connected to a negative terminal tab 41 and a positive terminal tab 42 of the electrode assembly 40 and applies continuous pulses.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present description relates to an apparatus and method for inspecting electrode assemblies for short circuits in secondary batteries. [Background technology]

[0002] Unlike primary batteries, rechargeable batteries are batteries that can be repeatedly charged and discharged. Small-capacity secondary batteries are used in small, portable electronic devices such as mobile phones, laptops, and camcorders, while large-capacity secondary batteries can be used as power sources for driving motors in hybrid and electric vehicles.

[0003] For example, a secondary battery includes an electrode assembly that charges and discharges, a pouch that houses the electrode assembly, and electrode terminals that electrically connect the electrode assembly and extend to the outside of the pouch.

[0004] The electrode assembly includes a winding type in which negative and positive electrode plates are wound on both sides with a separator between them, and a stacking type in which negative and positive electrode plates are stacked on both sides with a separator between them.

[0005] Medium- to large-sized cells have large-area separators stacked in multiple layers, which acts like a capacitor and allows it to store electrical charges. These separators have micro-short circuits such as tiny pinholes. After formation, pinholes or micro-short circuits can concentrate electrochemical reactions, potentially causing salt deposition and fire problems.

[0006] The principle of short circuit testing is that when current / voltage is applied to the electrode assembly, the lattices at the micro-short circuit sites in the separator collide with electrons and are ionized, and the generated electrons then collide with other lattices and are ionized again, causing a short circuit while raising the temperature in a short period of time. Summary of the Invention [Problem to be solved by the invention]

[0007] One embodiment of the present invention provides an electrode assembly short circuit inspection device for a secondary battery that applies an enhanced short circuit inspection method (continuous pulse application) when inspecting an electrode assembly for short circuits.

[0008] One embodiment of the present invention provides an electrode assembly short circuit inspection device for a secondary battery that improves the surface pressure applied to the electrode assembly to detect micro-short circuit areas in the electrode assembly that may become a problem later.

[0009] Another embodiment of the present invention provides a method for testing a short circuit in an electrode assembly of a secondary battery using the device for testing a short circuit in an electrode assembly of a secondary battery. [Means for solving the problem]

[0010] According to one embodiment of the present invention, an electrode assembly short circuit testing device for a secondary battery includes a first plate that applies pressure to one side of an electrode assembly having a negative electrode and a positive electrode disposed with a separator therebetween, a second plate that faces the first plate and applies pressure to the other side of the electrode assembly, and a continuous pulse machine that is connected to a negative electrode tab and a positive electrode tab of the electrode assembly and applies continuous pulses.

[0011] At least one of the first plate and the second plate may be formed of a silicon pad.

[0012] The first plate and the second plate may include a first silicon pad that contacts the electrode assembly, and a second silicon pad that is disposed on the first silicon pad and receives a pressure.

[0013] The first silicon pad may be formed of a single plate, and the second silicon pad may be formed of a plurality of plates.

[0014] The plurality of pieces of the second silicone pad can have two different thicknesses and two different hardnesses.

[0015] The first silicone pad may have a first thickness and a first hardness, and the plurality of slices of the second silicone pad may differ from each other in at least one of thickness and hardness.

[0016] Among the plurality of pieces of the second silicone pad, a piece located at the widthwise center may have a 21st thickness (t21) and a 21st hardness, and a piece located at the widthwise outer edge may have a 22nd thickness (t22) greater than the 21st thickness and a 22nd hardness greater than the 21st hardness.

[0017] The first silicone pad has a 31st thickness and a 31st hardness, the plurality of pieces of the second silicone pad have the same 32nd thickness, and among the plurality of pieces of the second silicone pad, a piece located at the widthwise center has a 33rd hardness, and a piece located at the widthwise outer edge has a 34th hardness, and the 33rd hardness may be smaller than the 34th hardness.

[0018] The first silicone pad has a 41st thickness and a 41st hardness, the plurality of pieces of the second silicone pad have the same 42nd hardness, and among the plurality of pieces of the second silicone pad, a piece located at the widthwise center has a 43rd thickness (t43), and a piece located at the widthwise outer edge has a 44th thickness (t44), and the 43rd thickness (t43) may be smaller than the 44th thickness (t44).

[0019] The first plate may be formed of a micro nylon pad, and the second plate may be formed of a Teflon pad.

[0020] The first plate may be formed of a PC sheet or a sloped Teflon pad, and the second plate may include a tile-type silicon pad and a jig for fixing the silicon pad.

[0021] A method for testing a short circuit in an electrode assembly of a secondary battery according to one embodiment of the present invention includes a first step of applying pressure between a first plate supporting a bottom surface of an electrode assembly having a negative electrode and a positive electrode disposed thereon with a separator therebetween and a second plate supporting an top surface of the electrode assembly above the first plate; a second step of applying continuous pulses having a current and a voltage to the negative electrode tab and the positive electrode tab of the electrode assembly using a continuous pulse machine; a third step of measuring the voltage and current of the continuous pulses applied to the electrode assembly; and a fourth step of determining a short circuit when the voltage drops to zero and determining completion of charging when the current stabilizes.

[0022] In the first step, at least one of the first plate and the second plate may be formed of a silicon pad and pressed.

[0023] In the first step, the first plate and the second plate may be formed by a first silicon pad that contacts the electrode assembly and a second silicon pad that is disposed on the first silicon pad and receives a pressure, and then pressurized.

[0024] In the first step, the first silicon pad may be formed from a single plate, and the second silicon pad may be formed from a plurality of cut plates, which may then be pressed together.

[0025] The first step may include forming a plurality of pieces of the second silicon pad to have at least one of two thicknesses and two hardnesses, and then pressing the pieces.

[0026] In the first step, the first silicone pad may have a first thickness and a first hardness, and the second silicone pad may have a plurality of pieces that are different from each other in at least one of thickness and hardness, and may be pressed.

[0027] In the first step, the second silicon pad may be pressed by giving a piece located at the widthwise center of the second silicon pad a 21st thickness (t21) and a 21st hardness, and giving a piece located at the outer periphery a 22nd thickness (t22) greater than the 21st thickness and a 22nd hardness greater than the 21st hardness.

[0028] In the first step, the first silicone pad may be pressurized by giving the first silicone pad a first thickness and a first hardness, giving the plurality of pieces of the second silicone pad the same second thickness, and making the hardness of the pieces located at the outer periphery higher than the hardness of the pieces located at the widthwise center.

[0029] In the first step, the first silicone pad may be pressed by giving the first silicone pad one first thickness and one first hardness, giving the plurality of pieces of the second silicone pad the same hardness, and making the 44th thickness of the piece located on the periphery greater than the 43rd thickness of the piece located at the widthwise center. [Effects of the Invention]

[0030] In one embodiment, continuous pulses are applied during short circuit testing of the electrode assembly, thereby maximizing short circuit testing capabilities. In addition, in one embodiment, the electrode assembly is pressed to improve surface pressure, and the surface pressure is uniformly transmitted, thereby effectively detecting micro-short circuit areas in the electrode assembly that may become a problem later. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a configuration diagram of an electrode assembly short-circuit inspection device for a secondary battery according to a first embodiment of the present invention; [Figure 2] FIG. 10 is a configuration diagram of an electrode assembly short-circuit testing device for a secondary battery according to a second embodiment of the present invention. [Figure 3] FIG. 10 is a configuration diagram of an electrode assembly short-circuit testing device for a secondary battery according to a third embodiment of the present invention. [Figure 4] FIG. 10 is a configuration diagram of an electrode assembly short-circuit testing device for a secondary battery according to a fourth embodiment of the present invention. [Figure 5] FIG. 10 is a configuration diagram of an electrode assembly short-circuit testing device for a secondary battery according to a fifth embodiment of the present invention. [Figure 6] FIG. 10 is a configuration diagram of an electrode assembly short-circuit testing device for a secondary battery according to a sixth embodiment of the present invention. [Figure 7] 3 is an image of a first silicon pad (hardness 20) applied to the second embodiment of FIG. 2 and a metal foreign substance attached thereto. [Figure 8] 4 is an image of a first silicon pad (hardness 50) applied to the third embodiment of FIG. 3 and a metal foreign substance attached thereto. [Figure 9] 5 is an image of a first silicon pad (hardness 80 degrees) applied to the fourth embodiment of FIG. 4 and a metal foreign substance attached thereto. [Figure 10] 22 is an image of a PP sheet applied to the seventh embodiment of FIG. 21 and a metallic foreign substance attached thereto. [Figure 11] 1 is a plan view showing a position for short-circuit testing of an electrode assembly of a secondary battery according to an embodiment of the present invention; [Figure 12] 10 is an image showing a surface pressure distribution of an electrode assembly of a secondary battery according to a comparative example. [Figure 13] 10 is an image showing a surface pressure distribution of an electrode assembly when the electrode assembly short-circuit inspection device for a secondary battery according to the first embodiment of the present invention is applied. [Figure 14] 10 is an image showing a surface pressure distribution of an electrode assembly when the electrode assembly short-circuit inspection device for a secondary battery according to a second embodiment of the present invention is applied. [Figure 15] 10 is an image showing a surface pressure distribution of an electrode assembly when the electrode assembly short-circuit inspection device for a secondary battery according to a third embodiment of the present invention is applied. [Figure 16] 10 is an image showing a surface pressure distribution of an electrode assembly when the secondary battery electrode assembly short circuit inspection device according to the fourth embodiment of the present invention is applied. [Figure 17] 3 is a flowchart of a method for testing a short circuit in an electrode assembly of a secondary battery according to an embodiment of the present invention. [Figure 18]This is a graph showing the state in the inspection method of FIG. 17 where the voltage drops to 0 and a short circuit is detected. [Figure 19] 18 is a graph showing the current being stable and charging being determined to be complete during the test method of FIG. 17; [Figure 20] FIG. 10 is a configuration diagram of an electrode assembly short-circuit testing device for a secondary battery according to a seventh embodiment of the present invention. [Figure 21] 13 is an image showing a surface pressure distribution of an electrode assembly when the secondary battery electrode assembly short circuit inspection device according to the seventh embodiment of the present invention is applied. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, 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. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts unnecessary for explanation are omitted, and the same reference numerals are used throughout the specification to refer to the same or similar components.

[0033] Meanwhile, when a pulse is applied to the electrode assembly, that is, when 500V, the international insulation resistance measurement standard (IEC93), is applied continuously with short intervals, a short circuit occurs in the area where the insulation of the separator in the electrode assembly is weak, and this short circuit is detected. A small short circuit, which is difficult to detect, will not be detected when 500V is applied once, but when it is applied in a pulsed manner, the detection power is increased and the short circuit can be detected effectively.

[0034] When 500V is applied once, a pulse current passes through the micro-short circuit area, generating heat, but the area quickly reaches thermal equilibrium and recovers its insulation. However, the principle of detection using the continuous pulse method is that a pulse current is continuously applied to the micro-short circuit area before thermal equilibrium is reached, allowing the area to be detected through the accumulation of thermal energy.

[0035] The electrode assembly short-circuit inspection method of the following embodiment is configured to apply a continuous pulse to the electrode assembly and determine whether the electrode assembly has a micro-short circuit and whether buffering is required. The electrode assembly short-circuit inspection device of the embodiment is configured to realize such an electrode assembly short-circuit inspection method. For convenience, the electrode assembly short-circuit inspection device for a secondary battery will be described first.

[0036] 1 is a block diagram of an electrode assembly short-circuit inspection device for a secondary battery according to a first embodiment of the present invention. Referring to FIG. 1, the electrode assembly short-circuit inspection device 1 of the first embodiment includes a first plate 10 (hereinafter referred to as the "lower plate"), a second plate 20 (hereinafter referred to as the "upper plate"), and a continuous pulse machine 30.

[0037] The lower plate 10 supports and applies pressure (P) to one side (for example, the lower side) of the electrode assembly 40, in which the negative electrode and the positive electrode are disposed with a separator therebetween. The upper plate 20 faces the lower plate 10 and supports and applies pressure (P) to the other side (for example, the upper side) of the electrode assembly 40 from above.

[0038] The lower plate 10 and the upper plate 20 improve the surface pressure on the portions of the electrode assembly 40 where pressure is insufficient, thereby increasing the detection rate of foreign matter in the electrode assembly 40 .

[0039] For example, at least one of the lower and upper plates 10 and 20 may be formed of a silicon pad. In the first embodiment, in order to uniform the surface pressure, silicon pads are applied to the lower and upper plates 10 and 20. For example, the silicon pad has a thickness of 7 mm and a hardness of 50 degrees.

[0040] The continuous pulse machine 30 is connected to the negative electrode tab 41 and the positive electrode tab 42 of the electrode assembly 40 and applies continuous pulses. The application of continuous pulses increases the foreign object detection rate for areas of the electrode assembly 40 that are frequently pressed.

[0041] In the first embodiment, the surface pressure is improved for the parts of the lower and upper plates 10 and 20 that are not pressed well, and the continuous pulse machine 30 applies continuous pulses to the parts that are pressed well, thereby significantly increasing the foreign object detection rate for the entire area of ​​the electrode assembly 40.

[0042] In addition, pressure reducing papers 43 and 44 are provided on the lower and upper surfaces of the electrode assembly 40, and when the electrode assembly 40 is pressed against the lower and upper plates 10 and 20, the pressure reducing papers 43 and 44 allow direct visual confirmation of whether the surface pressure on the electrode assembly 40 is uniform.

[0043] Various embodiments of the present invention will be described below. Descriptions of identical and similar components compared to the first embodiment and the previously described embodiments will be omitted, and only different components will be described.

[0044] 2 is a configuration diagram of an electrode assembly short-circuit inspection device for a secondary battery according to a second embodiment of the present invention. Referring to FIG. 2, in the electrode assembly short-circuit inspection device 2 of the second embodiment, a first plate 210 and a second plate 220 include first silicon pads 211, 221 that contact the electrode assembly 40, and second silicon pads 212, 222 that are disposed on the first silicon pads 211, 221 and receive pressure.

[0045] The first silicon pads 211, 221 of the first and second plates 210, 220 are each formed from a single plate and support and press (P) the lower and upper surfaces of the electrode assembly 40, while the second silicon pads 212, 222 are each formed from multiple cut plates. The cut plates of the second silicon pads 212, 222 have two thicknesses and two hardnesses. Note that "cut plates" refers to the multiple plates that make up one pad.

[0046] In the second embodiment, the first silicone pads 211 and 221 of the first and second plates 210 and 220 have the same first thickness (t1) and first hardness. For example, the first silicone pads 211 and 221 have a first thickness (t1) of 3 mm and a first hardness of 50. The second silicone pads 212 and 222 are formed to have at least one of different thickness and hardness.

[0047] In the second embodiment, the slices 213, 223 located at the center of the width direction (left-right direction in FIG. 2 ) of the second silicone pads 212, 222 of the first and second plates 210, 220 have a 21st thickness (t21) and a 21st hardness. For example, the slices 213, 223 have a 21st thickness (t21) of 3 mm and a 21st hardness of 50 degrees. The slices 214, 224 located on the periphery have a 22nd thickness (t22) that is greater than the 21st thickness (t21) and a 22nd hardness that is greater than the 21st hardness. For example, the slices 214, 224 have a 22nd thickness (t22) of 6 mm and a 22nd hardness of 50 degrees.

[0048] The continuous pulse machine 30 is connected to the negative electrode tab 41 and the positive electrode tab 42 of the electrode assembly 40 and applies continuous pulses. The application of continuous pulses increases the foreign object detection rate for areas of the electrode assembly 40 that are frequently pressed.

[0049] In the second embodiment, the surface pressure is improved for the areas that are not well pressed by the first silicon pads 211, 221 and the second silicon pads 212, 222 of the lower and upper plates 210, 220, and the continuous pulse machine 30 applies continuous pulses to the areas that are well pressed, thereby significantly increasing the foreign object detection rate for the entire area of ​​the electrode assembly 40.

[0050] Since the outermost pieces 214 and 224 are thicker and harder than the pieces 213 and 223 located at the center in the width direction, the surface pressure is further improved in the areas that were not pressed well relatively, thereby greatly increasing the foreign object detection rate for the entire area of ​​the electrode assembly 40.

[0051] In addition, pressure reducing papers 43 and 44 are provided on the lower and upper surfaces of the electrode assembly 40, and when pressure (P) is applied to the electrode assembly 40 by the first silicone pads 211 and 221 and the second silicone pads 212 and 222 of the lower and upper plates 210 and 220, the pressure reducing papers 43 and 44 allow direct visual confirmation of whether the surface pressure on the electrode assembly 40 is uniform.

[0052] 3 is a configuration diagram of an electrode assembly short-circuit inspection device for a secondary battery according to a third embodiment of the present invention. Referring to FIG. 3, in the electrode assembly short-circuit inspection device 3 of the third embodiment, a first plate 310 and a second plate 320 include first silicon pads 311 and 321 that contact the electrode assembly 40, and second silicon pads 312 and 322 that are disposed on the first silicon pads 311 and 321 and receive pressure.

[0053] The first and second plates 310 and 320 each have a single silicon pad 311, 321 that supports and applies pressure (P) to the upper and lower surfaces of the electrode assembly 40, while the second silicon pads 312, 322 are each made of multiple pieces of silicon. The pieces of silicon pad 312, 322 have at least two different hardness levels.

[0054] In the third embodiment, the first silicone pads 311 and 321 of the first and second plates 310 and 320 have a thickness (t31) of 3 mm and a hardness of 31. For example, the first silicone pads 311 and 321 have a thickness (t31) of 3 mm and a hardness of 80 degrees.

[0055] In the third embodiment, the second silicon pads 312, 322 of the first and second plates 310, 320 have the same thickness t32. For example, the thickness t32 is 5 mm. The second silicon pads 312, 322 have a hardness 33 of 20 degrees for example. The outer edges of the second silicon pads 312, 322 have a hardness 34 of 80 degrees for example. The hardness 33 at the center of the width (left-right direction in FIG. 3) is smaller than the hardness 34 at the outer edges of the width.

[0056] In the third embodiment, the second silicone pads 312, 322 further include plates 315, 325 inserted between the central plates 313, 323 and the outer plates 314, 324. For example, the inserted plates 315, 325 have a thickness (t32) of 5 mm and a hardness of 50. In other words, the second silicone pads 312, 322 have the same thickness, and the hardness of the plates gradually decreases from the outer periphery to the center in the width direction.

[0057] In the third embodiment, the surface pressure is improved for the areas that are not pressed well by the first silicon pads 311, 321 and the second silicon pads 312, 322 of the lower and upper plates 310, 320, and continuous pulses are applied to the areas that are pressed well by the continuous pulse machine 30, thereby greatly increasing the foreign object detection rate for the entire area of ​​the electrode assembly 40.

[0058] The hardness of the inserted pieces 315 and 325 is higher than that of the pieces 313 and 323 located at the widthwise center, and the hardness of the pieces 314 and 324 located on the outer periphery is higher than that of the pieces 315 and 325. Therefore, the surface pressure is further improved in the areas that were not pressed well relatively, and the foreign object detection rate can be greatly increased for the entire area of ​​the electrode assembly 40.

[0059] In addition, pressure reducing papers 43 and 44 are provided on the lower and upper surfaces of the electrode assembly 40, and when pressure (P) is applied to the electrode assembly 40 by the first silicon pads 311 and 321 and the second silicon pads 312 and 322 of the lower and upper plates 310 and 320, the pressure reducing papers 43 and 44 allow direct visual confirmation of whether the surface pressure on the electrode assembly 40 is uniform.

[0060] 4 is a configuration diagram of an electrode assembly short-circuit inspection device for a secondary battery according to a fourth embodiment of the present invention. Referring to FIG. 4, in the electrode assembly short-circuit inspection device 4 of the fourth embodiment, a first plate 410 and a second plate 420 include first silicon pads 411 and 421 that contact the electrode assembly 40, and second silicon pads 412 and 422 that are disposed on the first silicon pads 411 and 421 and receive pressure.

[0061] The first and second plates 410, 420 each have a single silicon pad 411, 421 that supports and applies pressure (P) to the upper and lower surfaces of the electrode assembly 40, while the second silicon pads 412, 422 are each made of multiple cut silicon plates that have at least two different thicknesses.

[0062] In the fourth embodiment, the first silicone pads 411 and 421 of the first and second plates 410 and 420 have a thickness (t41) of 3 mm and a hardness of 50 degrees.

[0063] In the fourth embodiment, the second silicon pads 412, 422 of the first and second plates 410, 420 have the same 42 hardness. For example, the 42 hardness is 50 degrees. The second silicon pads 412, 422 have a 43 thickness (t43) of 5 mm at the center of their width (left-right direction in FIG. 4 ). The outer edges of the second silicon pads 414, 424 have a 44 thickness (t44) of 6 mm at the center of their width (left-right direction in FIG. 4 ). The 43 thickness (t43) at the center of their width (left-right direction in FIG. 4 ) is smaller than the 44 thickness (t44) at the outer edges of their width (left-right direction).

[0064] In the fourth embodiment, the second silicone pads 412, 422 further include plates 415, 425 inserted between the central plates 413, 423 and the outer plates 414, 424. For example, the inserted plates 415, 425 have a thickness (t45) of 6 mm. That is, the second silicone pads 412, 422 have the same hardness, and the thickness of the plates gradually decreases from the outer periphery to the center in the width direction.

[0065] In the fourth embodiment, the surface pressure is improved for the areas that are not well pressed by the first silicon pads 411, 421 and the second silicon pads 412, 422 of the lower and upper plates 410, 420, and continuous pulses are applied to the areas that are well pressed by the continuous pulse machine 30, thereby greatly increasing the foreign object detection rate for the entire area of ​​the electrode assembly 40.

[0066] Since the thickness of the inserted pieces 415, 425 is greater than that of the pieces 413, 423 located at the center in the width direction, and the thickness of the outer pieces 414, 424 is greater than that of the pieces 415, 425, the surface pressure is further improved in the areas that were not pressed well relatively, and the foreign object detection rate can be greatly increased for the entire area of ​​the electrode assembly 40.

[0067] In addition, pressure reducing papers 43 and 44 are provided on the lower and upper surfaces of the electrode assembly 40, and when pressure (P) is applied to the electrode assembly 40 by the first silicone pads 411 and 421 and the second silicone pads 412 and 422 of the lower and upper plates 410 and 420, the pressure reducing papers 43 and 44 allow direct visual confirmation of whether the surface pressure on the electrode assembly 40 is uniform.

[0068] 5 is a diagram showing the configuration of an electrode assembly short-circuit testing device for a secondary battery according to a fifth embodiment of the present invention. Referring to FIG. 5, in the electrode assembly short-circuit testing device 5 of the fifth embodiment, a lower plate 510 is formed of a micro nylon pad, and an upper plate 520 is formed of a Teflon pad.

[0069] In the fifth embodiment, the surface pressure is improved in areas that are not pressed well by the nylon pads and Teflon pads of the lower and upper plates 510 and 520, and continuous pulses are applied to areas that are pressed well by the continuous pulse machine 30, thereby significantly increasing the foreign object detection rate for the entire area of ​​the electrode assembly 50. The continuous pulse machine 30 is connected to the negative electrode tab 51 and the positive electrode tab 52 of the electrode assembly 50 and applies continuous pulses.

[0070] 6 is a configuration diagram of an electrode assembly short-circuit inspection device for a secondary battery according to a sixth embodiment of the present invention. Referring to FIG. 6, in the electrode assembly short-circuit inspection device 6 of the sixth embodiment, a lower plate 610 is formed of a PC sheet or a sloped Teflon pad, and an upper plate 620 includes a tile-type silicone pad 621 and a jig 622 for fixing the silicone pad 621. The tile-type silicone pad 621 has an uneven structure on the side opposite the electrode assembly 50, so that the silicone pad 621 can effectively improve the surface pressure on parts of the electrode assembly 50 that are difficult to press.

[0071] In the sixth embodiment, the inclined Teflon pads and silicone pads 621 on the lower and upper plates 610 and 620 improve the surface pressure on the areas that are not pressed well, and the continuous pulse machine 30 applies continuous pulses to the areas that are pressed well, thereby significantly increasing the foreign object detection rate for the entire area of ​​the electrode assembly 50.

[0072] Figure 7 shows an image of a first silicon pad (hardness 20) and metal foreign particles attached thereto, which are applied to the second embodiment of Figure 2. Referring to Figure 7, the first silicon pads 211 and 221 have a hardness of 20 and attract a large amount of foreign particles and dust. The metal foreign particles attached to the surface have a particle size of 25 μm or less.

[0073] Figure 8 is an image of a first silicon pad (hardness 50) and a metal foreign substance attached thereto, which is applied to the third embodiment of Figure 3. Referring to Figure 8, the first silicon pads 311 and 321 have a hardness of 50 and adsorb foreign substances and dust. The metal foreign substances attached to the surface have a particle size of 10 μm to 50 μm.

[0074] Fig. 9 is an image of a first silicon pad (hardness 80) and a metal foreign substance attached thereto, which is applied to the fourth embodiment of Fig. 4. Referring to Fig. 9, the first silicon pads 411 and 421 have a hardness of 80 and adsorb foreign substances and dust. The metal foreign substances attached to the surface have a particle size of 10 μm to 50 μm.

[0075] Figure 10 is an image of the PP sheet and metal foreign matter attached thereto, which is applied to the seventh embodiment of Figure 21. Referring to Figure 10, the degree of foreign matter attachment to the surfaces of the polypropylene (PP) sheets 711 and 721 is significantly lower than that of the first silicone pad.

[0076] 20 is a configuration diagram of an electrode assembly short-circuit inspection device for a secondary battery according to a seventh embodiment of the present invention. Referring to FIG. 20, in the electrode assembly short-circuit inspection device 7 of the seventh embodiment, a first plate 710 and a second plate 720 include PP sheets 711 and 721 that come into contact with the electrode assembly 40, and silicone pads 712 and 722 that are disposed on the PP sheets 711 and 721 and receive pressure.

[0077] The PP sheets 711 and 721 of the first and second plates 710 and 720 are each formed from a single sheet to support and pressurize (P) the lower and upper surfaces of the electrode assembly 40, and the silicone pads 712 and 722 are each formed from a plurality of cut pieces. The cut pieces of the silicone pads 712 and 722 have at least two different hardnesses. The silicone pads 712 and 722 have the same structure as the second silicone pads 312 and 322 of the third embodiment, so a detailed description of the silicone pads 712 and 722 will be omitted here.

[0078] In the seventh embodiment, the surface pressure is improved in the areas that are not pressed well by the PP sheets 711, 721 and the silicone pads 712, 722 of the lower and upper plates 710, 720, and continuous pulses are applied to the areas that are pressed well by the continuous pulse machine 30, thereby greatly increasing the foreign object detection rate for the entire area of ​​the electrode assembly 40.

[0079] 7 to 10, it can be seen that the degree of adhesion of surface foreign matter decreases as the hardness of the silicone pad increases. The size of the metal foreign matter attached to the surface of the silicone pad is 10 μm to 50 μm. Furthermore, when PP sheets 711 and 721 are interposed between the silicone pads 712 and 722 and the electrode assemblies 40 and 50, adhesion of foreign matter can be significantly improved.

[0080] 11 is a plan view showing a position for short-circuit testing of an electrode assembly of a secondary battery applied to an embodiment of the present invention. Referring to FIG. 11, the electrode assembly 40 applied to the first to fourth embodiments is shown in plan view, and the first to fifteenth regions ((1) to (15)) are numbered.

[0081] 12 is an image showing the surface pressure distribution of the electrode assembly of a secondary battery according to a comparative example, which shows the surface pressure distribution obtained through pressure reducing paper when the electrode assembly is pressed by the first and second plates of an electrode assembly short circuit inspection device (not shown) for a secondary battery that does not use a silicone pad.

[0082] 11 and 12, when the applied pressure (P) was 0.94 Ma, pressure was applied to 68% of the total area of ​​the electrode assembly. Further pressure was observed in the 7th to 9th regions ((7) to (9)), which are the winding core of the electrode assembly, the 1st to 3rd regions ((1) to (3)) and the 13th to 15th regions ((13) to (15)), which are the round regions, and the 6th, 9th, and 12th regions ((6), (9), and (12)), which are the taping regions.

[0083] 13 is an image showing the surface pressure distribution of an electrode assembly when the electrode assembly short circuit inspection device for a secondary battery according to the first embodiment of the present invention is applied. Referring to FIG. 13, the surface pressure distribution obtained through pressure reducing papers 43 and 44 when the electrode assembly 40 is pressed by the first and second plates 10 and 20 formed of silicone pads according to the first embodiment is shown.

[0084] 11 and 13, when the applied pressure (P) was 1.5 Ma, pressure was applied to 86% of the total area of ​​the electrode assembly. It was confirmed that the pressure was low in the first to third regions ((1) to (3)), the thirteenth to fifteenth regions ((13) to (15)), the sixth, ninth, and twelfth regions ((6), (9), and (12)), and the fourth, seventh, and eleventh regions ((4), (7), and (11)) of the edge portion of the electrode assembly. It was confirmed that the surface pressure distribution was improved in the first example compared to the comparative example.

[0085] 14 is an image showing the surface pressure distribution of an electrode assembly when the electrode assembly short circuit inspection device for a secondary battery according to the second embodiment of the present invention is applied. Referring to FIG. 14, the surface pressure distribution obtained through the pressure reducing papers 43 and 44 when the electrode assembly 40 is pressed by the first and second plates 210 and 220 formed of silicone pads according to the second embodiment is shown.

[0086] 11 and 14, when the applied pressure (P) was 1.5 Ma, pressure was applied to 100% of the entire area of ​​the electrode assembly. The pressure was improved in the edge areas of the electrode assembly, namely, regions 1 to 3 ((1) to (3)), regions 13 to 15 ((13) to (15)), regions 6, 9, and 12 ((6), (9), and (12)), and regions 4, 7, and 11 ((4), (7), and (11)). It can be seen that the surface pressure distribution was improved in the second example compared to the first example.

[0087] 15 is an image showing the surface pressure distribution of an electrode assembly when the electrode assembly short circuit inspection device for a secondary battery according to the third embodiment of the present invention is applied. Referring to FIG. 15, the surface pressure distribution obtained through pressure reducing papers 43 and 44 when the electrode assembly 40 is pressed by the first and second plates 310 and 320 formed of silicone pads according to the third embodiment is shown.

[0088] 11 and 15, when the applied pressure (P) was 1.5 Ma, pressure was applied to 100% of the entire area of ​​the electrode assembly. The seventh to ninth regions ((7), (8), and (9)) in the center of the electrode assembly were improved from being pressed. It can be seen that the surface pressure distribution in the third example was more uniform than in the second example.

[0089] 16 is an image showing the surface pressure distribution of an electrode assembly when the secondary battery electrode assembly short circuit inspection device according to the fourth embodiment of the present invention is applied. Referring to FIG. 16, the surface pressure distribution obtained through pressure reducing papers 43 and 44 when the electrode assembly 40 is pressed by first and second plates 410 and 420 formed of silicone pads according to the fourth embodiment is shown.

[0090] 11 and 16, when the applied pressure (P) was 1.5 Ma, pressure was applied to 100% of the entire area of ​​the electrode assembly. It was confirmed that the pressure was small in the fourth and tenth regions ((4) and (10)) of the tab portion of the electrode assembly. It was confirmed that the surface pressure distribution in the fourth example was roughly similar to that in the third example.

[0091] 21 is an image showing the surface pressure distribution of an electrode assembly when the electrode assembly short circuit inspection device for a secondary battery according to the seventh embodiment of the present invention is applied. Referring to FIG. 21, the surface pressure distribution obtained through the pressure reducing papers 43 and 44 when the electrode assembly 40 is pressed by the first and second plates 710 and 720 formed of silicone pads according to the seventh embodiment is shown.

[0092] Referring to Figures 11 and 21, when the applied pressure (P) was varied, the pressure in the first, fourth, seventh, tenth, and thirteenth regions ((1), (4), (7), (10), and (13)) of the tab portion of the electrode assembly was improved, and foreign matter was detected.

[0093] 17 is a flowchart of a method for testing a short circuit in an electrode assembly of a secondary battery according to an embodiment of the present invention. The method for testing a short circuit in an electrode assembly of a secondary battery according to an embodiment of the present invention includes a first step (ST1), a second step (ST2), a third step (ST3), and a fourth step (ST4). First, the testing method will be described using the testing device of the first embodiment.

[0094] Referring to Figures 1 and 17, in the first step (ST1), pressure (P) is applied to a first plate 10 supporting the lower surface of an electrode assembly 40 in which a negative electrode and a positive electrode are disposed with a separator therebetween, and a second plate 20 supporting the upper surface of the electrode assembly 40 from above the first plate 10.

[0095] In the first embodiment, in the first step (ST1), at least one of the first plate 10 and the second plate 20 is formed of a silicon pad and pressurized, so that a pressure distribution as shown in FIG. 13 can be obtained.

[0096] In the second step (ST2), continuous pulses having a current and a voltage are applied to the negative electrode tab 41 and the positive electrode tab 42 of the electrode assembly 40 by the continuous pulse machine 30. In the third step (ST3), the voltage and current of the continuous pulses applied to the electrode assembly 40 are measured. In the fourth step (ST4), if the voltage drops to 0, it is determined that a short circuit has occurred, and if the current stabilizes, it is determined that charging is complete (see FIG. 18).

[0097] 2 to 4 and 17, in the second to fourth embodiments, the first step (ST1) is to form the first plate 210, 310, 410 and the second plate 220, 320, 420 with first silicon pads 211, 221; 311, 321; 411, 421 that contact the electrode assembly 40, and second silicon pads 212, 222; 312, 322; 412, 422 that are placed on the first silicon pads and receive pressure, and then apply pressure (P).

[0098] In the second to fourth embodiments, in the first step (ST1), the first silicon pads 211, 221; 311, 321; 411, 421 are formed from a single plate, and the second silicon pads 212, 222; 312, 322; 412, 422 are formed from a plurality of cut plates, and then pressure is applied (P).

[0099] In the second to fourth embodiments, the first step (ST1) involves forming the second silicon pads 212, 222; 312, 322; 412, 422 into pieces with two different thicknesses and two different hardnesses, and applying pressure (P).

[0100] Referring to Figures 2 and 17, in the second embodiment, the first step (ST1) involves giving the first silicon pads 211 and 221 a first thickness (t1) and a first hardness, and applying pressure (P) to the pieces of the second silicon pads 212 and 222 such that at least one of the thickness and hardness is different from each other.

[0101] More specifically, in the first step (ST1), the second silicon pad 212, 222 has the center pieces 213, 223 of the second silicon pad 212, 222, and the outer pieces 214, 224 are given a thickness (t22) and a hardness (t22) greater than the thickness (t21) and a hardness (t22) greater than the hardness (t21) in the width direction, and then pressurized (P). This results in a pressure distribution as shown in FIG. 14.

[0102] 3 and 17, in the third embodiment, in the first step (ST1), the first silicon pads 311 and 321 are given the same thickness (t31) and first hardness, the pieces of the second silicon pads 312 and 322 are given the same thickness (t32), and the hardness of the outer silicon pads 314 and 324 is made higher than the hardness of the widthwise center silicon pads 313 and 323. Then, pressure (P) is applied, resulting in a pressure distribution as shown in FIG.

[0103] 4 and 17, in the fourth embodiment, in the first step (ST1), the first silicon pads 411 and 421 are given the same thickness (t41) and first hardness, the pieces of the second silicon pads 412 and 422 are given the same hardness, and the thickness (t44) of the outer silicon pads 414 and 424 is made larger than the thickness (t43) of the widthwise center silicon pads 423 and 423, and then pressure (P) is applied, resulting in a pressure distribution as shown in FIG.

[0104] FIG. 18 is a graph showing the voltage dropping to 0 during the test method of FIG. 17, indicating a short circuit, and FIG. 19 is a graph showing the current stabilizing during the test method of FIG. 17, indicating a charge completion.

[0105] 17 and 18, in the fourth step (ST4), when the voltage of the electrode assembly drops to 0, it is determined that a short circuit has occurred (the lower line in FIG. 18), and when the current stabilizes, it is determined that charging is complete (the upper line in FIG. 18).

[0106] 17 and 19, it can be seen that the equilibrium voltage of the electrode assembly increases gradually as successive pulses of current are applied. The greater the applied current, the greater the ability to charge the capacitance of the electrode assembly.

[0107] Although the preferred embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made within the scope of the claims, the description of the invention, and the accompanying drawings, and it is natural that these also fall within the scope of the present invention. [Explanation of symbols]

[0108] 1, 2, 3, 4, 5, 6, 7 electrode assembly short circuit inspection device 10 First Plate 20 Second Plate 30 Continuous Pulse Machine 40, 50 Electrode Assembly 41, 51 Negative electrode tab 42, 52 Positive tab 43, 44 Decompression paper 210 Plate 1 220 Second Plate 211, 221 First Silicone Pad 212, 222 Second silicone pad 213, 223 Cut board 214, 224 Cut board 310 First Plate 311, 321 First Silicone Pad 312, 322 Second silicone pad 313, 323 Cut board 314, 324 Cut board 315, 325 Cut board 320, 420 2nd plate 410 First Plate 411, 421 1st Silicone Pad 412, 422 Second silicone pad 413, 423 Cut board 414, 424 Cut board 415, 425 Cut board 510 Lower Plate 520 Upper Plate 610 Lower Plate 620 Upper Plate 621 Tile-shaped silicone pad 622 Jig 710 First Plate 720 Second Plate 711, 721 PP sheet 712, 722 Silicone Pads P Pressurization t1 First thickness t21 21st thickness t22 22nd thickness t31 31st thickness t32 32nd thickness t41 41st thickness t43 43rd thickness t44 44th thickness

Claims

1. a first plate that presses one side of the electrode assembly in which the negative electrode and the positive electrode are disposed with the separator therebetween; a second plate facing the first plate and pressing the other side of the electrode assembly; and A continuous pulse machine is connected to the negative electrode tab and the positive electrode tab of the electrode assembly to apply continuous pulses.

1. An electrode assembly short-circuit testing device for a secondary battery, comprising:

2. The device for testing a short circuit in an electrode assembly of a secondary battery according to claim 1 , wherein at least one of the first plate and the second plate is formed of a silicon pad.

3. The first plate and the second plate are a first silicon pad in contact with the electrode assembly; and 2. The device for testing short circuits in an electrode assembly of a secondary battery according to claim 1, further comprising a second silicon pad disposed on the first silicon pad and receiving a pressure.

4. the first silicon pad is formed of a single plate; 4. The device for testing short circuits in an electrode assembly of a secondary battery according to claim 3, wherein the second silicon pad is formed of a plurality of strips.

5. The plurality of pieces of the second silicon pad are 5. The secondary battery electrode assembly short circuit inspection device according to claim 4, which has two types of thickness and two types of hardness.

6. the first silicone pad has a first thickness and a first hardness; 5. The device for testing short circuits in an electrode assembly of a secondary battery according to claim 4, wherein the plurality of pieces of the second silicon pad are different from each other in at least one of thickness and hardness.

7. The second silicon pad has a plurality of pieces of silicon pad, and a piece of silicon pad located at a widthwise center of the second silicon pad has a 21st thickness (t21) and a 21st hardness.

7. The device for inspecting short circuits in an electrode assembly of a secondary battery according to claim 6, wherein the piece located on the outer periphery in the width direction has a 22nd thickness (t22) greater than the 21st thickness and a 22nd hardness greater than the 21st hardness.

8. the first silicone pad has a 31st thickness and a 31st hardness; the plurality of slices of the second silicon pad have the same 32nd thickness; The piece of the second silicon pad located at the center in the width direction among the plurality of pieces of the second silicon pad has a hardness of 33. The pieces located on the outer periphery in the width direction have a hardness of 34, The device for inspecting short circuits in an electrode assembly of a secondary battery according to claim 4 , wherein the 33rd hardness is lower than the 34th hardness.

9. the first silicone pad has a 41st thickness and a 41st hardness; the plurality of pieces of the second silicone pad have the same 42 hardness; The piece located at the center of the width direction of the second silicon pad among the plurality of pieces has a 43rd thickness (t43), The piece located on the outer periphery in the width direction has a 44th thickness (t44), The device for inspecting a short circuit in an electrode assembly of a secondary battery according to claim 4 , wherein the forty-third thickness (t43) is smaller than the forty-fourth thickness (t44).

10. The first plate and the second plate are a PP sheet in contact with the electrode assembly; and a silicone pad disposed on the PP sheet and receiving a pressure; 2. The device for testing short circuits in an electrode assembly of a secondary battery according to claim 1, wherein the silicon pad is formed of a plurality of pieces.

11. The first plate is made of a PC sheet or a slanted Teflon pad; The second plate is Tile-type silicone pads, and The secondary battery electrode assembly short circuit inspection device according to claim 1 , further comprising a jig for fixing the silicon pad.

12. a first step of pressing the electrode assembly with a first plate supporting a lower surface of the electrode assembly, in which a negative electrode and a positive electrode are disposed with a separator therebetween, and a second plate supporting an upper surface of the electrode assembly above the first plate; a second step of applying continuous pulses having a current and a voltage to the negative electrode tab and the positive electrode tab of the electrode assembly by a continuous pulse machine; a third step of measuring the voltage and current of successive pulses applied to the electrode assembly; and a fourth step of determining that a short circuit has occurred when the voltage drops to 0 and determining that charging has been completed when the current stabilizes; A method for inspecting an electrode assembly for a short circuit in a secondary battery, comprising:

13. The first step comprises: The method of claim 12, wherein at least one of the first plate and the second plate is formed of a silicon pad and is pressed.

14. The first step comprises: The first plate and the second plate, a first silicon pad in contact with the electrode assembly; and 13. The method of claim 12, wherein the pressure is applied by forming a second silicon pad on the first silicon pad to receive the pressure.

15. The first step comprises: The first silicon pad is formed as a single plate; 15. The method of claim 14, wherein the second silicon pad is formed of a plurality of strips and is pressed.

16. The first step comprises: a plurality of pieces of the second silicon pad; 16. The method for testing a short circuit in an electrode assembly of a secondary battery according to claim 15, wherein the electrode assembly is formed to have two different thicknesses and two different hardnesses and then pressed.

17. The first step comprises: the first silicone pad has a first thickness and a first hardness; 16. The method of claim 15, wherein the second silicon pad is pressed such that the plurality of pieces of the second silicon pad have at least one of different thickness and hardness.

18. The first step comprises: The second silicon pad has a plurality of pieces of the second silicon pad, and the piece of the second silicon pad located at the center of the width direction has a 21st thickness (t21) and a 21st hardness.

18. The method for testing a short circuit in an electrode assembly of a secondary battery according to claim 17, wherein a piece of plate located on the outer periphery has a second thickness (t22) greater than the second thickness and a second hardness greater than the first hardness, and is then pressed.

19. The first step comprises: the first silicone pad has a first thickness and a first hardness; the plurality of slices of the second silicon pad having the same second thickness; 16. The method for testing a short circuit in an electrode assembly of a secondary battery according to claim 15, wherein the hardness of the outer periphery of the electrode assembly is set higher than the hardness of the widthwise center of the electrode assembly when the electrode assembly is pressed.

20. The first step comprises: the first silicone pad has a first thickness and a first hardness; The plurality of pieces of the second silicon pad have the same hardness; 16. The method for testing a short circuit in an electrode assembly of a secondary battery according to claim 15, wherein the forty-fourth thickness of the outermost piece is made larger than the forty-third thickness of the widthwise center piece when the electrode assembly is pressed.

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