Electrode resistance measuring device

Abstract

The present invention relates to an electrode resistance measuring device, and provides an electrode resistance measuring device that can measure the surface pass-through resistance of an electrode layer formed on one surface of a current collector.

Description

[Technical Field]

[0001] This application claims priority under Republic of Korea Patent Application No. 10-2024-0076169 dated 12 June 2024, and all content disclosed in the literature of said Republic of Korea Patent Application is incorporated herein by reference.

[0002] The present invention relates to an electrode resistance measuring device, and more particularly to an electrode resistance measuring device for measuring the through-plane resistance of an electrode layer formed on one surface of a current collector. [Background technology]

[0003] Generally, rechargeable batteries are batteries that can be used repeatedly through a discharge process that converts chemical energy into electrical energy, and a charging process that converts electrical energy into chemical energy. Types of rechargeable batteries include nickel-cadmium (Ni-Cd) batteries, nickel-metal hydride (Ni-MH) batteries, lithium metal batteries, lithium-ion (Li-ion) batteries, and lithium-ion polymer batteries. Among these rechargeable batteries, lithium-ion batteries, which have high energy density and voltage, long cycle life, and low self-discharge rate, have been commercialized and are widely used.

[0004] The electrodes of a secondary battery include a negative electrode (anode) and a positive electrode (cathode). Specifically, inside a secondary battery, the negative electrode and positive electrode are stacked with a separator membrane in between.

[0005] Methods for measuring the resistance of electrodes in secondary batteries, including the negative and positive electrodes, are divided into in-plane resistance measurement methods and through-plane resistance measurement methods.

[0006] Since the resistance through the surface is actually measured in the same direction as the flow of electrons when the rechargeable battery is operating, it has a direct correlation with the performance of the rechargeable battery.

[0007] Furthermore, since surface resistance can be used to determine the vertical non-uniformity of electrodes coated using the wet coating method, it can be utilized in quality control of secondary batteries.

[0008] The existing method for measuring surface resistance, as shown in Figure 1, involves placing a pair of terminals 1101 and 1102 for measuring the resistance of electrode 1011 in close contact with both sides of electrode 1011, and then applying current to both terminals 1101 and 1102 through a power supply 1200 to measure the resistance. The terminals 1101 and 1102 for measuring the resistance of the electrode have contact surfaces formed on a flat plane. In this case, if the contact resistance between electrode 1011 and terminals 1101 and 1102 is high, the reproducibility of the surface resistance measurement decreases.

[0009] Conventionally, to improve the reproducibility of surface-to-surface resistance measurements, a method was used in which multiple electrodes were stacked, pressed under high pressure, and then measured. However, this measurement method also had difficulties in obtaining uniform values ​​due to the accumulated contact resistance between the multiple electrodes, and between the outermost electrode and the terminal, as well as contact inconsistencies caused by steps and other factors. Furthermore, analysis methods performed by stacking many electrodes had difficulties in analyzing the characteristics of individual electrodes.

[0010] Furthermore, the secondary battery electrodes consist of a configuration in which electrode layers are stacked on both sides of a current collector, formed by applying, drying, and pressurizing an electrode slurry.

[0011] Incidentally, there are times when it is required to measure the surface resistance of only one electrode layer relative to the current collector, but existing methods make it difficult to measure the surface resistance of individual electrode layers that can be separated relative to the current collector.

[0012] To solve the aforementioned problems, a surface resistance measurement technique is needed that offers excellent reproducibility and can measure even individual electrode layers that can be separated based on the current collector. [Overview of the Initiative] [Problems that the invention aims to solve]

[0013] The present invention relates to an electrode resistance measuring device, and aims to provide an electrode resistance measuring device that can measure the surface pass resistance of an electrode layer formed on one surface of a current collector. This is to determine the surface pass resistance between the surface of the current collector and the surface of the outer electrode for an electrode formed on one surface of the current collector.

[0014] The technical problems that this invention aims to solve are not limited to those described above, and any other technical problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0015] To solve the aforementioned technical problems, the present invention provides an electrode resistance measuring device for measuring the resistance of an electrode including a current collector and an electrode layer formed on one or both sides of the current collector, the device comprising: a first terminal portion that is electrically connected to the exposed surface of the electrode layer by direct contact; a second terminal portion that is electrically connected to the current collector by direct contact; and a resistance measuring portion for measuring the electrical resistance between the first terminal portion and the second terminal portion, wherein the surface of the first terminal portion that contacts the electrode layer is made of a microporous layer, and the second terminal portion includes fixing means that is fixed to the plain portion of the current collector.

[0016] According to one embodiment, the material of the microporous layer contains one or more of carbon, conductive metals, and conductive polymers.

[0017] According to one embodiment, the fine porous layer of the first terminal portion is located on the bottom surface of the conductive pressure plate of the rigid material D 50 Fine particles with a diameter of 5 μm or less, or a fine fiber network with a width of 10 μm or less, are coated or bonded to form the structure, and the material of the fine particles or the fine fiber network contains one or more of the following: transition metals, aluminum, carbon, and conductive polymers.

[0018] According to one embodiment, the first terminal portion includes a conductive pressure plate made of a conductive material and having a bottom surface formed in a plane perpendicular to the vertical direction, and a contact layer fixed to the bottom surface of the conductive pressure plate. The contact layer includes the microporous layer, and the bottom surfaces of the contact layer and the conductive pressure plate are also fixed by a conductive paste layer.

[0019] According to one embodiment, the material of the conductive pressure plate includes one or more of transition metals, aluminum, and carbon.

[0020] According to one embodiment, the contact layer includes the microporous layer and a carbon fiber layer.

[0021] According to one embodiment, the upper surface of the carbon fiber layer is adhered to the bottom surface of the conductive pressure plate by the conductive paste layer, and the microporous layer is laminated on the bottom surface of the carbon fiber layer.

[0022] According to one embodiment, the conductive paste layer is formed by applying and drying a mixture of conductive particles, a binder, and a solvent. The material of the conductive particles includes one or more of carbon black, graphite, CNT, graphene, transition metals, and aluminum. The size of the conductive particles is D 50 is also 20 μm or less.

[0023] According to one embodiment, the conductive paste layer is formed to have a thickness of 10 to 200 μm between the contact layer and the conductive pressure plate.

[0024] According to one embodiment, the porosity of the microporous layer is also 30 to 80%.

[0025] According to one embodiment, the thickness of the microporous layer is also 20 to 150 μm.

[0026] According to one embodiment, the carbon fiber layer is made of carbon paper or carbon cloth, and the fine porous layer is made of D at the bottom surface of the carbon fiber layer. 50 Fine particles with a diameter of 5 μm or less, or a fine fiber network with a width of 10 μm or less, are coated or bonded to form the structure, and the material of the fine particles or the fine fiber network contains one or more of the following: transition metals, aluminum, carbon, and conductive polymers.

[0027] According to one embodiment, the fixing means includes a clip that makes surface or line contact with the current collector, and the fixing means is made of a conductive material.

[0028] According to one embodiment, the device further includes a support plate that supports the bottom surface of the electrode. [Effects of the Invention]

[0029] The electrode resistance measuring device of the present invention can measure the surface resistance of an electrode layer formed on one surface of a current collector.

[0030] The electrode resistance measuring device of the present invention measures the surface resistance of secondary battery electrodes and can measure the resistance of each individual electrode layer (electrode layers formed on both sides of the current collector) with high reproducibility, based on the current collector.

[0031] The electrode resistance measuring device of the present invention measures the plane-pass resistance of secondary battery electrodes and can measure the resistance of individual electrode layers (each of the electrode layers formed on both sides of the current collector) at different in-plane positions with high reproducibility, based on the current collector. This makes it possible to understand the uniformity of the resistance at different positions of the individual electrode layers.

[0032] The electrode resistance measuring device of the present invention can minimize the contact resistance between the electrode and the terminal when measuring the resistance passing through the surface.

[0033] The electrode resistance measuring device of the present invention has a fine porous conductive layer formed on the surface of the terminal that contacts the electrode, which adheres completely to the rough surface of the individual electrode, thereby enabling the measurement of resistance to the individual electrode while minimizing contact resistance. [Brief explanation of the drawing]

[0034] [Figure 1] This is a perspective view illustrating a conventional method for measuring surface-to-surface resistance. [Figure 2] This is a perspective view showing one embodiment of the electrode resistance measuring device of the present invention. [Figure 3] This is a cross-sectional view showing the state in which the first terminal portion and the second terminal portion are connected to the secondary battery electrode. [Figure 4] This is a perspective view showing the measurement state using the electrode resistance measuring device of the present invention. [Figure 5] This is a perspective view showing another embodiment of the electrode resistance measuring device of the present invention. [Figure 6] This is a perspective view showing yet another embodiment of the electrode resistance measuring device of the present invention. [Figure 7] This graph shows the results of electrode resistance measurement. [Modes for carrying out the invention]

[0035] The embodiments of the present invention will be described in detail below with reference to the attached drawings. In this process, the size and shape of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. Furthermore, terms specifically defined in consideration of the configuration and operation of the present invention may vary depending on the intent or convention of the user or operator. The definitions of such terms should be based on the overall content of this specification.

[0036] In describing the present invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "up," "down," "left," "right," "vertical," "horizontal," "inside," "outside," "one side," and "other side" are based on the directions or positional relationships shown in the drawings, or the directions or positional relationships in which the product of the present invention is typically arranged during use. They are merely for the purpose of describing and briefly explaining the present invention, and do not imply or suggest that the displayed device or element must necessarily be configured or operated in a specific direction, and should not be understood as limiting the present invention.

[0037] Figure 2 is a perspective view showing one embodiment of the electrode resistance measuring device of the present invention. Figure 3 is a cross-sectional view showing the state in which the first terminal portion 100 and the second terminal portion 200 are connected to the secondary battery electrode 10. Figure 4 is a perspective view showing the measurement state using the electrode resistance measuring device of the present invention. Figure 5 is a perspective view showing another embodiment of the electrode resistance measuring device of the present invention. Figure 6 is a perspective view showing yet another embodiment of the electrode resistance measuring device of the present invention. Figure 7 is a graph showing the results of electrode resistance measurement.

[0038] The electrode resistance measuring device of the present invention will be described below with reference to Figures 2 to 7.

[0039] The electrode resistance measuring device of the present invention is for measuring the surface resistance of a secondary battery electrode 10. Specifically, the secondary battery electrode 10 to be measured by the electrode resistance measuring device of the present invention includes a current collector 12 and an electrode composite material layer (electrode layer) laminated on the upper surface or the entire upper and lower surfaces of the current collector 12. That is, the secondary battery electrode 10 has an electrode layer 11 formed on one or both surfaces of the current collector 12.

[0040] The current collector 12 is a metal foil. That is, the current collector 12 is a thin conductive metal film with a thickness of approximately 10 μm.

[0041] The electrode layer 11 is formed on one or both sides of the current collector 12 in a state in which the active material, conductive material, and binder are mixed. Preferably, the electrode layer 11 can be formed on both sides of the current collector 12. Specifically, the electrode layer 11 can be formed by applying an electrode slurry, which is made by mixing and kneading the active material, conductive material, binder, and solvent, to the current collector 12, and then applying heat and pressure. The area of ​​the electrode layer 11 can be formed to be smaller than the area of ​​the current collector 12. In this case, the area of ​​the current collector 12 that is not covered by the electrode layer 11 is referred to as the plain area.

[0042] In the electrode to be analyzed according to the present invention, the blank portion of the current collector 12 may be formed by partially removing the electrode layer 11. For example, if the region where the blank portion is formed is the positive electrode, a portion of the electrode composite layer can be removed using N-methylpyrrolidone (NMP), and if it is the negative electrode, water can be used to remove a portion of the electrode composite layer.

[0043] The electrode resistance measuring device of the present invention is capable of independently measuring the surface pass-through resistance (or through-pass resistance) of one electrode layer 11 among the electrode layers 11 formed on both sides of the current collector 12 in a secondary battery electrode 10. Specifically, even for a secondary battery electrode 10 in which electrode layers 11 are formed on both sides of the current collector 12, the electrode resistance measuring device of the present invention can measure the surface pass-through resistance value of one electrode layer 11.

[0044] As shown in Figure 2, the electrode resistance measuring device of the present invention includes a first terminal portion 100 that is electrically connected by directly contacting the upper surface (exposed surface) of the upper electrode layer 11 of the secondary battery electrode 10; a second terminal portion 200 that is electrically connected by directly contacting the current collector 12; and a resistance measuring unit 300 for measuring the electrical resistance between the first terminal portion 100 and the second terminal portion 200. The surface of the first terminal portion 100 that contacts the electrode layer 11 is made of a microporous layer 111, and the second terminal portion 200 includes fixing means 210 that are fixed to the plain portion of the current collector 12.

[0045] If there are no blank areas on the electrode to be analyzed, the electrode layer 11 can be peeled off to form a blank area and connect the second terminal portion 200. As mentioned above, if the area where the blank area is to be formed is the positive electrode, NMP can be used; if it is the negative electrode, water can be applied to remove the electrode layer 11.

[0046] The surface of the electrode layer 11 is formed when the electrode slurry dries, and depending on the circumstances, it may be formed roughly and not an ideal plane. In the electrode resistance measuring device of the present invention, the first terminal portion 100 is in complete contact with the rough surface of the electrode layer 11 through the microporous layer 111, thereby preventing an increase in resistance due to poor contact. The material of the microporous layer 111 contains one or more of carbon, conductive metals, and conductive polymers.

[0047] As one embodiment, as shown in Figures 2 and 3, the first terminal portion 100 includes a conductive pressure plate 120 made of a conductive material, the bottom surface of which is a plane perpendicular to the vertical direction, a contact layer 110 whose upper surface is fixed to the bottom surface of the conductive pressure plate 120, and a first conductor 130 that electrically connects the conductive pressure plate 120 and the resistance measuring portion 300.

[0048] As shown in Figures 2 to 6, the area of ​​the bottom surface of the first terminal portion 100 can be formed to be smaller than the area of ​​the electrode layer 11.

[0049] As shown in Figure 4, the area of ​​the bottom surface of the first terminal portion 100 can be formed to be significantly smaller than the area of ​​the electrode layer 11. For example, the area of ​​the bottom surface of the first terminal portion 100 may be 1 / 300 to 1 / 3 of the area of ​​the electrode layer 11, but is not limited to this. As shown in Figure 4, by moving the first terminal portion 100 on the upper surface of the electrode layer 11 and measuring at multiple points, the uniformity of the resistance at different positions in the electrode layer 11 can be determined.

[0050] As another embodiment, as shown in Figure 5, in the electrode resistance measuring device of the present invention, a plurality of first terminals 100 are provided, and each of the plurality of first terminals 100 is assigned a different identification code.

[0051] The resistance measuring unit 300 sequentially inputs a signal to each of the multiple first terminals 100, obtains an identified resistance value for each of the multiple first terminals 100, and measures multiple points on the upper surface of the electrode layer 11 at the first terminals 100, thereby enabling the uniformity of resistance at different positions in the electrode layer 11.

[0052] The conductive pressure plate 120 also has a bottom surface formed as a plane perpendicular to the vertical direction. More preferably, both the top and bottom surfaces of the conductive pressure plate 120 are formed as planes perpendicular to the vertical direction.

[0053] The material of the conductive pressure plate 120 contains one or more of the transition metals, aluminum, and carbon from the periodic table. For example, transition metals can also be iron, copper, titanium, nickel, etc. Another example is a conductive pressure plate 120 in which a conductive material such as silver is coated on the surface of a rigid material. That is, the conductive pressure plate 120 is made of a rigid conductive material.

[0054] The contact layer 110 includes a microporous layer 111, and the contact layer 110 and the conductive pressure plate layer 120 are bonded together by a conductive paste layer 140.

[0055] The conductive paste layer 140 is obtained by mixing conductive particles, a binder, and a solvent in a paste state, the material of the conductive particles includes one or more of the following: carbon black, graphite, CNT, graphene, transition metals, and aluminum, and the size of the conductive particles is D 50 The thickness is also 20 μm or less. The conductive paste layer 140 is also formed between the contact layer 110 and the conductive pressure plate 120 to a thickness of 10 to 200 μm. The thickness of the conductive paste layer 140 is determined considering the condition of the carbon fiber layer 112 or the smoothness of the conductive pressure plate 120.

[0056] The contact layer 110 includes the fine porous layer 111 and the carbon fiber layer 112. For example, the contact layer 110 is also a gas diffusion layer (GDL).

[0057] The carbon fiber layer 112 is bonded to the bottom surface of the conductive pressure plate 120 by the conductive paste layer 140, and the fine porous layer 111 is laminated on the bottom surface of the carbon fiber layer 112.

[0058] In other words, the electrode resistance measuring device of the present invention adheres a carbon fiber layer 112 to a conductive pressure plate 120 made of a material that easily forms a flat surface with high quality smoothness using a conductive paste layer 140, and by making the fine porous layer 111 side in close contact with the surface of the electrode layer 11 where the smoothness is reduced, contact resistance can be minimized and reproducibility can be improved when measuring surface transmission resistance.

[0059] The porosity of the microporous layer 111 is 30-80%, and the thickness of the microporous layer 111 is 20-150 μm. More preferably, the porosity of the microporous layer 111 is 40-70%.

[0060] Porosity refers to the volume of voids relative to the total volume of a microporous layer and is measured through a variety of methods used in the field.

[0061] The carbon fiber layer 112 is made of carbon paper or carbon cloth, and the fine porous layer 111 is made of D on the bottom surface of the carbon fiber layer 112. 50 Fine particles with a diameter of 5 μm or less, or a fine fiber network with a width of 10 μm or less, are coated or bonded to form the structure, and the material of the fine particles or the fine fiber network contains one or more of the following: transition metals, aluminum, carbon, and conductive polymers.

[0062] As described above, the contact layer 110 may include a fine porous layer 111 formed by applying a carbon paste to a carbon fiber layer 112 such as carbon paper or carbon cloth, followed by drying and heat treatment. The carbon paste formed in the fine porous layer 111 after drying and heat treatment is obtained by mixing carbon powder, fluororesin, water, and alcohol. The fluororesin is one or more selected from the group consisting of polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene-ethylene copolymer (ETFE), and polyfluorovinylidene (PVDF).

[0063] The carbon fiber layer 112 is made of carbon fibers. These carbon fibers (CF) are fibrous carbon materials with a carbon element mass content of 90% or more. Specifically, carbon fibers are mostly graphite-structured fibers obtained by pyrolysis of organic precursor fibers (substances before carbonization). Furthermore, the carbon fiber layer 112 is coated with fluororesin.

[0064] In another embodiment, the microporous layer 111 is located on the bottom surface of the rigid conductive pressure plate 120. 50 Fine particles with a diameter of approximately 5 μm or less, or a fine fiber network with a width of approximately 10 μm or less, may be coated or bonded to form the first terminal portion 100. In this case, the material of the fine particles or fine fiber network coated or bonded to the first terminal portion 100 contains one or more of the following: transition metals, aluminum, carbon, and conductive polymers.

[0065] As shown in FIG. 6, the electrode resistance measuring apparatus of the present invention may further include a load body 150 laminated on the upper surface of the conductive pressing plate 120 in order to press the secondary battery electrode 10. A plurality of load bodies 150 may be provided. When measuring the surface passing resistance, the magnitude of the pressure for pressing the secondary battery electrode 10 by the first terminal portion 100 can affect the measurement result. Therefore, it is necessary to press the secondary battery electrode 10 with an appropriate level of pressure, and the number of load bodies 150 can be adjusted to adjust the pressure with which the first terminal portion 100 presses the secondary battery electrode 10. The pressure with which the first terminal portion 100 presses the secondary battery electrode 10 is preferably about 0.01 to 0.2 kgf / cm 2 is desirable. If the pressure with which the first terminal portion 100 presses the secondary battery electrode 10 is less than about 0.01 kgf / cm 2 , the contact resistance increases and the measurement accuracy decreases. If it exceeds about 0.2 kgf / cm 2 , the thickness of the secondary battery electrode 10 changes, and more precisely, the thickness of the electrode layer 11 changes, which can affect the measured value.

[0066] The conductive pressing plate 120 and the load body 150 are also disk-shaped. For accurate measurement in the electrode resistance measuring apparatus of the present invention, it is important that the first terminal portion 100 does not tilt. Therefore, the conductive pressing plate 120 and the load body 150 may be disk-shaped so as not to have anisotropy with respect to the direction perpendicular to the vertical direction. The conductive pressing plate 120 may be provided with alignment means (not shown) for aligning the center of the load body 150 with the center of the conductive pressing plate 120. The alignment means may also be a protrusion, a groove, a marker, or the like. The first wire 130 for electrical connection between the conductive pressing plate 120 and the resistance measuring unit 300 is coupled to the side surface of the conductive pressing plate 120 so as not to interfere with the lamination of the load bodies 150. When there is no load body 150, the first wire 130 is connected to the upper surface of the conductive pressing plate 120 as shown in FIG. 2.

[0067] In addition to such a load body, the magnitude of the pressure for pushing the pressing plate 120 can be adjusted using a machine that applies pressure.

[0068] In another embodiment, the first terminal portion 100 includes a conductive pressure plate 120 made of a rigid material and the fine porous layer 111 laminated on the bottom surface of the conductive pressure plate 120. Specifically, the fine porous layer 111 of the first terminal portion 100 is laminated on the bottom surface of the conductive pressure plate 120 made of a rigid material 50 The material is formed by coating or bonding fine particles with a diameter of 5 μm or less or a fine fiber network with a width of 10 μm or less, and the material of the fine particles or the fine fiber network contains one or more of the following: transition metals, aluminum, carbon, and conductive polymers. That is, a paste containing the fine particles or fine fiber network can be immediately applied to the bottom surface of a conductive pressure plate 120, which is a rigid support, and then dried and heat-treated to form a fine porous layer 111.

[0069] The second terminal section 200 may include the fixing means 210 which is electrically connected to the current collector 12, and the second conductor 230 which electrically connects the fixing means 210 and the resistance measuring section 300.

[0070] The fixing means 210 includes a clip that makes surface or line contact with the current collector 12. The fixing means 210 may consist of a conductive means. The fixing means 210 can apply elastic pressure to both sides of the current collector 12. For example, the fixing means 210 may include a first member that contacts one side of the current collector 12 and a second member that contacts the other side. The first member is a conductive rigid material that contacts the current collector 12 surface or line, and the second member is fitted with an elastic pad. The first and second members are in complete contact with each other, sandwiching the current collector 12 by the elastic force. Specifically, the surface of the second member contracts along the shape of the first member so that the current collector 12 is in complete contact with the first member without any gaps.

[0071] As shown in Figures 4 and 5, the fixing means 210 may have a shape that extends in the longitudinal direction of the edge of the current collector 12. That is, the fixing means 210 can simultaneously contact all of the long edges of the current collector 12, thereby minimizing the resistance error that occurs during measurement due to the position of the second electrode.

[0072] In another embodiment, the fixing means 210 may be provided in the form of a resistance probe, such as in the form of an alligator clip.

[0073] The resistance measuring unit 300 may include a current supply (not shown) that supplies input current between the first terminal section 100 and the second terminal section 200, and a voltmeter (not shown) that measures the voltage between the first terminal section 100 and the second terminal section 200. The input current is not limited to AC or DC and may vary depending on the purpose of analysis. The resistance measuring unit 300 is electrically connected to the first terminal section 100 and the second terminal section 200, respectively, through the first conductor 130 and the second conductor 230.

[0074] The first conductor 130 and the second conductor 230 are also electric wires whose core is made of a conductive material and whose surface is exposed to an insulating material.

[0075] The electrode resistance measuring device of the present invention further includes a support plate 400 that supports the bottom surface of the secondary battery electrode 10. The support plate 400 has an upper surface that is a plane perpendicular to the vertical direction, and the area of ​​the upper surface may be larger than the area of ​​the secondary battery electrode 10. The support plate 400 may be made of an insulating material.

[0076] Example 1 The positive electrode of a lithium secondary battery, in which electrode layers 11 are formed on both sides of the current collector 12, is measured at 100 cm. 2 The electrodes were prepared to the specified size, and the surface resistance of one side of the electrode layer was measured.

[0077] The conductive pressure plate 120 was made of copper material coated with gold, and the weight of the first terminal section 100 was prepared to be 0.3 kg.

[0078] The area of ​​the bottom surface of the first terminal section 100 is 4.9 cm². 2 That was the case.

[0079] The contact layer 110, which consists of a carbon fiber layer 112 laminated with a microporous layer 111, uses Sigracet 39 BC from SGL.

[0080] The conductive paste layer 140 was applied to the bottom surface of the conductive pressure plate 120 to a thickness of 20 μm to fix the contact layer 110.

[0081] The second terminal section 200 is fixed to the plain section of the current collector 12.

[0082] The first terminal portion 100 is positioned on the upper surface of the electrode layer 11 such that the outer edge of the bottom surface of the first terminal portion 100 is at the interface between the plain portion and the electrode layer 11, separated by approximately 2 cm.

[0083] A Hioki BT3563 HiTESTER from Hioki Corporation was used as the resistance measuring unit 300. A 1kHz AC current was applied as the input current between the first terminal 100 and the second terminal 200.

[0084] The positive electrode of the lithium secondary battery was completely separated from the first terminal portion 100 and the second terminal portion 200, then reconnected and measured three times.

[0085] Example 2 The surface resistance of the electrode layer opposite to the electrode layer measured in Example 1 was measured.

[0086] The measurement conditions were the same as in Example 1.

[0087] The positive electrode of the lithium secondary battery was completely separated from the first terminal portion 100 and the second terminal portion 200, then reconnected and measured three times.

[0088] Example 3 The surface pass-through resistance of the same electrode layer was measured in the same manner as in Example 1, except that the contact layer 110 and the conductive pressure plate 120 were not fixed with the conductive paste layer 140.

[0089] Example 4 The resistance of the electrode layer on the opposite side was measured in the same manner as in Example 3, except that the contact layer 110 and the conductive pressure plate 120 were not fixed with the conductive paste layer 140.

[0090] Comparative Example 1 The surface pass-through resistance was measured for the same electrode layer in the same manner as in Example 1, except that no contact layer or conductive paste layer was formed on the bottom surface of the first terminal portion 100, and it consisted of a single layer of conductive pressure plate 120.

[0091] Comparative Example 2 The surface pass-through resistance was measured for the opposite electrode layer using the same method as in Comparative Example 1.

[0092] Figure 7 is a graph showing the results of resistance measurements for Examples 1 to 4, Comparative Example 1, and Comparative Example 2. The resistance values ​​shown in Figure 7 are the average values ​​of three repeated measurements. As shown in Figure 7, when a microporous layer 111 is present on the surface of the first terminal portion 100 that contacts the secondary battery electrode 10 in the through-surface resistance measurement, the measured resistance value decreases sharply to less than one-tenth. In particular, in the case of Example 1 and Comparative Example 1, the difference in measured resistance values ​​is approximately 25 times or more. Furthermore, the standard deviation of Examples 1 and 2 is significantly lower than that of Comparative Example 1 and Comparative Example 2. This is because the contact resistance that interferes with the measurement was minimized. In addition, the accuracy calculated for Examples 1 to 4, Comparative Example 1, and Comparative Example 2 was 3.8%, 3.2%, 10.5%, 7.6%, 9.2%, and 12.7%, respectively. The accuracy was calculated as a percentage of the standard deviation value relative to the average value of the electrode resistance. Examples 1 and 2 showed superior accuracy compared to Examples 3 and 4, and Comparative Examples 1 and 2. This is because the contact layer 110 was fixed using the conductive paste layer 140, minimizing contact resistance, enhancing the stability of the device, and resulting in excellent reproducibility.

[0093] Although embodiments of the present invention have been described above, these are merely illustrative, and those skilled in the art will understand that a wide variety of modifications and equivalent embodiments are possible. Therefore, the true scope of technical protection of the present invention must be determined by the claims. [Explanation of symbols]

[0094] 10: Secondary battery electrode 11: Electrode layer 12: Current collector 100: 1st terminal part 110: Contact layer 111: Microporous layer 112: Carbon fiber layer 120: Conductive pressure plate 130: 1st conductor 140: Conductive paste layer 150: Loading body 200: 2nd terminal part 210: Fixing means 230:Second conductor 300: Resistance measurement section 400: Support plate

Claims

1. An electrode resistance measuring device for measuring the resistance of an electrode, which includes a current collector and an electrode layer laminated on one or both sides of the current collector, A first terminal portion that is electrically connected by directly contacting the exposed surface of the electrode layer, A second terminal portion that is electrically connected by directly contacting the current collector, Includes a resistance measuring unit for measuring the electrical resistance between the first terminal portion and the second terminal portion, The first terminal portion has a surface that contacts the electrode layer made of a microporous layer, The electrode resistance measuring device includes a fixing means that is fixed to the plain portion of the current collector, wherein the second terminal portion is fixed to the plain portion of the current collector.

2. The electrode resistance measuring device according to claim 1, wherein the material of the microporous layer comprises one or more of carbon, conductive metals, and conductive polymers.

3. The fine porous layer of the first terminal portion is located on the bottom surface of the conductive pressure plate made of rigid material D ５０ Fine particles with a diameter of 5 μm or less, or a fine fiber network with a width of 10 μm or less, are coated or joined to form the material. The electrode resistance measuring device according to claim 1, wherein the material of the fine particles or the fine fiber network comprises one or more of a transition metal, aluminum, carbon, and a conductive polymer.

4. The first terminal portion is, A conductive pressure plate made of a conductive material and having a bottom surface formed in a plane perpendicular to the vertical direction, The conductive pressure plate includes a contact layer fixed to the bottom surface, The contact layer includes the fine porous layer, The electrode resistance measuring device according to claim 1, wherein the bottom surface of the contact layer and the conductive pressure plate are fixed by a conductive paste layer.

5. The electrode resistance measuring device according to claim 4, wherein the material of the conductive pressure plate includes one or more of transition metals, aluminum, and carbon.

6. The electrode resistance measuring device according to claim 4, wherein the contact layer includes the microporous layer and the carbon fiber layer.

7. The carbon fiber layer is bonded to the bottom surface of the conductive pressure plate by the conductive paste layer. The electrode resistance measuring device according to claim 6, wherein the fine porous layer is laminated on the bottom surface of the carbon fiber layer.

8. The conductive paste layer is obtained by coating and drying a mixture of conductive particles, a binder, and a solvent. The material of the conductive particles includes one or more of the following: carbon black, graphite, CNT, graphene, transition metals, and aluminum. The size of the conductive particle is D ５０ The electrode resistance measuring device according to claim 7, wherein the thickness is 20 μm or less.

9. The electrode resistance measuring device according to claim 8, wherein the conductive paste layer is formed to a thickness of 10 to 200 μm.

10. The electrode resistance measuring device according to claim 6, wherein the porosity of the microporous layer is 30 to 80%.

11. The electrode resistance measuring device according to claim 6, wherein the thickness of the microporous layer is 20 to 150 μm.

12. The carbon fiber layer includes carbon paper or carbon cloth. The aforementioned fine porous layer has a D at the bottom surface of the carbon fiber layer. ５０ Fine particles with a diameter of 5 μm or less, or a fine fiber network with a width of 10 μm or less, are coated or joined to form the material. The electrode resistance measuring device according to claim 6, wherein the material of the fine particles or the fine fiber network comprises one or more of a transition metal, aluminum, carbon, and a conductive polymer.

13. The fixing means includes a clip that makes surface or line contact with the current collector. The electrode resistance measuring device according to claim 1, wherein the fixing means is made of a conductive material.

14. The electrode resistance measuring device according to claim 1, further comprising a support plate for supporting the electrode.

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