Electrode resistance measuring device

Abstract

The invention relates to an electrode resistance measuring device. An object of the present disclosure is to provide an electrode resistance measuring device including: a first terminal portion in direct contact with an exposed surface of an electrode layer so as to be electrically connected thereto; a second terminal portion in direct contact with the current collector so as to be electrically connected thereto; and a resistance measuring part for measuring the resistance between a first terminal part having a surface in contact with the electrode layer and formed as a microporous layer and a second terminal part including a fixing member fixed to the uncoated portion of the current collector, thus the resistance measuring part is configured to measure the resistance between the first terminal part and the second terminal part. The through-plane resistance of an electrode layer formed on one surface of a current collector can be measured.

Description

Technical Field

[0001] This application claims priority based on Korean Patent Application No. 10-2024-0076169, filed on June 12, 2024, the entire disclosure of which is incorporated in this specification.

[0002] This disclosure relates to an electrode resistance measuring device, and more specifically, to an electrode resistance measuring device for measuring the through-plane resistance of an electrode layer formed on a surface of a current collector. Background Technology

[0003] Generally, a rechargeable battery is a battery that can be reused through a discharge process that converts chemical energy into electrical energy and a charging process that converts electrical energy back 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, lithium rechargeable batteries are commercially available and widely used due to their high energy density and voltage, long cycle life, and low self-discharge rate.

[0004] The electrodes of a secondary battery include an anode and a cathode. Specifically, the anode and cathode are stacked inside the secondary battery, with a separator between them.

[0005] Methods for measuring the resistance of electrodes in a secondary battery, including the anode and cathode, are divided into in-plane resistance measurement methods and through-plane resistance measurement methods.

[0006] Since the resistance of the through surface is measured in the same direction as the direction of electron flow during actual operation of the secondary battery, the resistance of the through surface is directly related to the performance of the secondary battery.

[0007] Furthermore, since the through-surface resistance can identify vertical non-uniformity of electrodes coated by wet coating methods, it can be used for quality control of secondary batteries.

[0008] like Figure 1 As shown, a conventional through-surface resistance measurement method is performed by contacting a pair of terminals 1101 and 1102 on the two side surfaces of electrode 1011 respectively to measure the resistance of electrode 1011, applying current to the two terminals 1101 and 1102 via power supply 1200, and measuring their resistance. The terminals 1101 and 1102 used to measure the resistance of the electrode have flat contact areas. Here, if the contact resistance between electrode 1011 and terminals 1101 and 1102 is high, the reproducibility of the through-surface resistance measurement is poor.

[0009] Conventionally, to improve the reproducibility of through-surface resistance measurements, a method is used where multiple electrodes are stacked, pressed together with high voltage, and the resistance is measured. However, this method struggles to obtain uniform values ​​due to contact inhomogeneities caused by accumulated contact resistance between the electrodes and between the outermost electrode and the terminal, as well as by steps and other factors. Furthermore, analytical methods performed by stacking multiple electrodes make it difficult to analyze the characteristics of each individual electrode.

[0010] In addition, the secondary battery electrode is formed by coating, drying and pressing the electrode slurry to form an electrode layer stacked on the two surfaces of the current collector.

[0011] However, sometimes it is necessary to measure the through-surface resistance of an electrode layer based on only one surface of the current collector, but it is difficult to measure the through-surface resistance of individual electrode layers based on the current collector using existing methods.

[0012] To address the aforementioned issues, a technique is needed that offers excellent reproducibility and enables the measurement of the through-surface resistance of individual electrode layers based on current collector partitioning. Summary of the Invention

[0013] Technical issues

[0014] This disclosure relates to an electrode resistance measuring device, and provides an electrode resistance measuring device capable of measuring the through-surface resistance of an electrode layer formed on one surface of a current collector. This disclosure thereby obtains the through-surface resistance between the surface of the current collector and the outer electrode surface of an electrode formed on one surface of the current collector.

[0015] The technical objectives to be achieved by this disclosure are not limited to those described above, and other technical objectives not mentioned will be clearly understood by those skilled in the art from the following description.

[0016] Technical solution

[0017] To achieve the above objectives, this disclosure provides: An electrode resistance measuring device is provided for measuring the resistance of an electrode, the electrode comprising a current collector and an electrode layer formed on one or both surfaces of the current collector. The electrode resistance measuring device includes: The first terminal portion is electrically connected to the exposed surface of the electrode layer by directly contacting the exposed surface of the electrode layer; The second terminal portion is electrically connected to the current collector through direct contact; and The resistance measuring unit is configured to measure the resistance between the first terminal and the second terminal. The surface of the first terminal portion that contacts the electrode layer is formed by a microporous layer, and The second terminal includes a fixing member that is fixed to the uncoated portion of the current collector.

[0018] According to one embodiment, the material of the microporous layer may include at least one selected from carbon, conductive metals, and conductive polymers.

[0019] According to one embodiment, D can be used to... 50 A microporous layer of the first terminal portion is formed by coating or bonding fine particles of less than 5 μm or a network of fine fibers with a width of less than 10 μm to the lower surface of a conductive press plate made of rigid material, and the material of the fine particles or the network of fine fibers may include at least one selected from transition metals, aluminum, carbon and conductive polymers.

[0020] According to one embodiment, the first terminal portion may include: a conductive pressing plate, the conductive pressing plate being made of a conductive material and having a lower surface, the lower surface of the conductive pressing plate being formed as a plane perpendicular to the vertical direction; and a contact layer, the contact layer being fixed to the lower surface of the conductive pressing plate, the contact layer including a microporous layer, and the contact layer and the lower surface of the conductive pressing plate being fixed by a conductive paste layer.

[0021] According to one embodiment, the material of the conductive press plate may include at least one selected from transition metals, aluminum, and carbon.

[0022] According to one embodiment, the contact layer may include a microporous layer and a carbon fiber layer.

[0023] According to one embodiment, the upper surface of the carbon fiber layer can be adhered to the lower surface of the conductive press plate by a conductive paste layer, and a microporous layer can be stacked on the lower surface of the carbon fiber layer.

[0024] According to one embodiment, a conductive paste layer can be formed by coating and drying a mixture of conductive particles, a binder, and a solvent. The material of the conductive particles may include at least one selected from carbon black, graphite, CNTs, graphene, transition metals, and aluminum, and the size of the conductive particles may be D. 50 It is below 20μm.

[0025] According to one embodiment, the conductive paste layer can be formed to have a thickness of 10 μm to 200 μm between the contact layer and the conductive pressing plate.

[0026] According to one embodiment, the porosity of the microporous layer can be from 30% to 80%.

[0027] According to one embodiment, the thickness of the microporous layer can be from 20 μm to 150 μm.

[0028] According to one embodiment, the carbon fiber layer can be made of carbon paper or carbon cloth, and can be achieved by applying D... 50A microporous layer is formed by coating or bonding fine particles of less than 5 μm or a network of fine fibers with a width of less than 10 μm to the lower surface of a carbon fiber layer, and the material of the fine particles or the network of fine fibers may include at least one selected from transition metals, aluminum, carbon and conductive polymers.

[0029] According to one embodiment, the fixing member may include a clamp that contacts the current collector surface or in line, and the fixing member may be made of a conductive material.

[0030] According to one embodiment, the electrode resistance measuring device may further include a support plate configured to support the lower surface of the electrode.

[0031] Beneficial effects

[0032] The electrode resistance measuring device disclosed herein can measure the through-surface resistance of an electrode layer formed on one surface of a current collector.

[0033] The electrode resistance measuring device disclosed herein can measure the resistance of individual electrode layers (electrode layers formed on the two surfaces of the current collector) based on the current collector with high reproducibility by measuring the through-surface resistance of the secondary battery electrode.

[0034] The electrode resistance measuring device disclosed herein can measure the resistance at each in-plane location of each electrode layer (each electrode layer formed on the two surfaces of the current collector) based on the current collector with high reproducibility by measuring the through-plane resistance of the secondary battery electrodes. This makes it possible to identify the resistance uniformity at each location of each electrode layer.

[0035] The electrode resistance measuring device disclosed herein can minimize the contact resistance between the electrode and the terminal when measuring the resistance of a through-plane.

[0036] The electrode resistance measuring device disclosed herein can measure the resistance of a single electrode with minimized contact resistance by forming a microporous conductive layer on the surface of the terminal that contacts the electrode and completely adhering the microporous conductive layer to the surface of the rough single electrode. Attached Figure Description

[0037] Figure 1 This is a perspective view illustrating a conventional method for measuring resistance across a through surface.

[0038] Figure 2 This is a perspective view illustrating an embodiment of the electrode resistance measuring device of this disclosure.

[0039] Figure 3 This is a cross-sectional view showing the first terminal portion and the second terminal portion connected to the secondary battery electrode.

[0040] Figure 4This is a perspective view showing the measurement status using the electrode resistance measuring device of this disclosure.

[0041] Figure 5 This is a perspective view showing another embodiment of the electrode resistance measuring device of this disclosure.

[0042] Figure 6 This is a perspective view showing yet another embodiment of the electrode resistance measuring device of this disclosure.

[0043] Figure 7 This is a coordinate graph showing the results of electrode resistance measurements. Detailed Implementation

[0044] In the following description, embodiments according to the present disclosure will be illustrated in detail with reference to the accompanying drawings. In this process, the dimensions or shapes of components shown in the drawings may be exaggerated for clarity and ease of explanation. Furthermore, the terminology specifically defined in consideration of the configuration and operation of this disclosure may vary according to the intentions or habits of the user and operator. The definitions of these terms should be based on the entire contents of this specification.

[0045] In the description of this disclosure, it should be noted that the orientation or positional relationship indicated by terms such as “center,” “up,” “down,” “left,” “right,” “vertical,” “horizontal,” “inner,” “outer,” “one side,” and “the other side” is based on the orientation or positional relationship shown in the accompanying drawings or the orientation or positional relationship when the product of this disclosure is placed in daily use, and is only used to explain and briefly describe this disclosure, and does not suggest or imply that the device or element shown must be configured or operated in a specified orientation, and should not be construed as limiting this disclosure.

[0046] Figure 2 This is a perspective view illustrating an embodiment of the electrode resistance measuring device of this disclosure. Figure 3 This 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 This is a perspective view showing the measurement status using the electrode resistance measuring device of this disclosure. Figure 5 This is a perspective view showing another embodiment of the electrode resistance measuring device of this disclosure. Figure 6 This is a perspective view showing yet another embodiment of the electrode resistance measuring device of this disclosure. Figure 7 This is a coordinate graph showing the results of electrode resistance measurements.

[0047] In the following text, reference will be made to Figures 2 to 7 The electrode resistance measuring device of this disclosure is described.

[0048] The electrode resistance measuring device disclosed herein can be used to measure the through-surface resistance of a secondary battery electrode 10. Specifically, the secondary battery electrode 10 to be measured by the electrode resistance measuring device of this disclosure may include a current collector 12 and an electrode composite layer (electrode layer) stacked on the upper surface or both the upper and lower surfaces of the current collector 12. In other words, the secondary battery electrode 10 may have an electrode layer 11 formed on one or both surfaces of the current collector 12.

[0049] The current collector 12 can be a metal foil. In other words, the current collector 12 can be a thin conductive metal film with a thickness of about 10 μm.

[0050] The electrode layer 11 can be formed on one or both surfaces of the current collector 12 in a mixture of active material, conductive material, and binder. Preferably, the electrode layer 11 can be formed on both surfaces of the current collector 12. Specifically, the electrode layer 11 can be formed by coating the current collector 12 with an electrode slurry made by mixing and kneading active material, conductive material, binder, and solvent, 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. Here, the area in the current collector 12 not covered by the electrode layer 11 is referred to as the uncoated portion.

[0051] In the electrodes to be analyzed in this disclosure, an uncoated portion of the current collector 12 can also be formed by removing a portion of the electrode layer 11. For example, if the area where the uncoated portion is to be formed is a cathode, a portion of the electrode composite layer can be removed using N-methylpyrrolidone (NMP), and if it is an anode, a portion of the electrode composite layer can be removed using water.

[0052] The electrode resistance measuring device disclosed herein can independently measure the through-surface resistance (or penetration resistance) of one of the electrode layers 11 formed on two surfaces centered on the current collector 12 of the secondary battery electrode 10. Specifically, the electrode resistance measuring device disclosed herein can measure the through-surface resistance value of one of the electrode layers 11 of the secondary battery electrode 10 in which electrode layers 11 are formed on the two surfaces of the current collector 12.

[0053] like Figure 2 As shown, the electrode resistance measuring device of this disclosure may include: The first terminal portion 100 is electrically connected to the upper surface (exposed surface) of the upper electrode layer 11 of the secondary battery electrode 10 by directly contacting it. The second terminal 200 is electrically connected to the current collector 12 via direct contact; and The resistance measuring unit 300 is configured to measure the resistance between the first terminal unit 100 and the second terminal unit 200. The surface of the first terminal portion 100 that contacts the electrode layer 11 can be formed of a microporous layer 111, and The second terminal portion 200 may include a fixing member 210 fixed to the uncoated portion of the current collector 12.

[0054] When there is no uncoated portion in the electrode to be analyzed, the electrode layer 11 can be peeled off to form an uncoated portion and connected to the second terminal portion 200. As described above, when the area where the uncoated portion is to be formed is a cathode, NMP can be applied to remove the electrode layer 11, and when it is an anode, water can be applied to remove the electrode layer 11.

[0055] The surface of the electrode layer 11 is formed by drying electrode paste and can be formed rough as needed, and may not be formed as an ideally flat surface. The electrode resistance measuring device of this disclosure can prevent an increase in resistance due to poor contact by ensuring that the first terminal portion 100 is completely adhered to the rough surface of the electrode layer 11 via the microporous layer 111. The material of the microporous layer 111 may include at least one selected from carbon, conductive metals, and conductive polymers.

[0056] In an embodiment, such as Figure 2 and Figure 3 As shown, the first terminal portion 100 may include: a conductive pressing plate 120 formed of a conductive material and having a lower surface, the lower surface of the conductive pressing plate 120 being a plane perpendicular to the vertical direction; a contact layer 110, the upper surface of which is fixed to the lower surface of the conductive pressing plate 120; and a first wire 130 electrically connecting the conductive pressing plate 120 and the resistance measuring portion 300.

[0057] like Figures 2 to 6 As shown, the area of ​​the lower surface of the first terminal portion 100 can be formed to be smaller than the area of ​​the electrode layer 11.

[0058] like Figure 4 As shown, the area of ​​the lower surface of the first terminal portion 100 can be formed to be sufficiently smaller than the area of ​​the electrode layer 11. For example, the area of ​​the lower surface of the first terminal portion 100 can be formed to be 1 / 300 to 1 / 3 of the area of ​​the electrode layer 11, but is not limited thereto. Figure 4 As shown, by moving the first terminal portion 100 on the upper surface of the electrode layer 11 and measuring multiple points, the resistance uniformity based on the position of the electrode layer 11 can be identified.

[0059] In another embodiment, such as Figure 5 As shown, in the electrode resistance measuring device disclosed herein, a plurality of first terminal portions 100 may be provided, and each of the plurality of first terminal portions 100 may be assigned a different identification code.

[0060] The resistance measurement unit 300 can sequentially input signals to each of the plurality of first terminal units 100, obtain an identified resistance value for each of the plurality of first terminal units 100, and measure a plurality of points on the upper surface of the electrode layer 11 at the first terminal unit 100, thereby identifying resistance uniformity for each position of the electrode layer 11.

[0061] The conductive pressing plate 120 may have a lower surface formed as a plane perpendicular to the vertical direction. More preferably, both the upper and lower surfaces of the conductive pressing plate 120 may be formed as planes perpendicular to the vertical direction.

[0062] The material of the conductive press plate 120 may include at least one selected from transition metals, aluminum, and carbon in the periodic table. For example, transition metals may be iron, copper, titanium, nickel, etc. As another example, the conductive press plate 120 may be a rigid material coated with a conductive material such as gold. In other words, the conductive press plate 120 may be made of a rigid conductive material.

[0063] The contact layer 110 may include a microporous layer 111, and the contact layer 110 and the conductive pressing plate 120 may be bonded together by a conductive paste layer 140.

[0064] Conductive paste layer 140 can be obtained by mixing conductive particles, binder, and solvent in a dough state, wherein the material of the conductive particles may include at least one selected from carbon black, graphite, CNT, graphene, transition metals, and aluminum, and the size of the conductive particles may be D. 50 The thickness is less than 20 μm. The conductive paste layer 140 can be formed between the contact layer 110 and the conductive pressing plate 120 with a thickness of 10 μm to 200 μm. The thickness of the conductive paste layer 140 can be determined by taking into account the state of the carbon fiber layer 112 or the smoothness of the conductive pressing plate 120.

[0065] The contact layer 110 may include a microporous layer 111 and a carbon fiber layer 112. For example, the contact layer 110 may be a gas diffusion layer (GDL).

[0066] The carbon fiber layer 112 can be adhered to the lower surface of the conductive pressing plate 120 by the conductive paste layer 140, and the microporous layer 111 can be stacked on the lower surface of the carbon fiber layer 112.

[0067] In other words, the electrode resistance measuring device of this disclosure can minimize contact resistance by using a conductive paste layer 140 to adhere the carbon fiber layer 112 to a conductive press plate 120 made of a material that facilitates the formation of a plane with high-quality smoothness, and by making the microporous layer 111 side in close contact with the surface of the electrode layer 11 which has poor smoothness, so as to improve reproducibility when measuring the surface penetration resistance.

[0068] The porosity of the microporous layer 111 can be from 30% to 80%, and the thickness of the microporous layer 111 can be from 20 μm to 150 μm. More preferably, the porosity of the microporous layer 111 can be from 40% to 70%.

[0069] Porosity refers to the volume of pores relative to the total volume of a microporous layer, and can be measured using various methods used in the relevant field.

[0070] The carbon fiber layer 112 can be made of carbon paper or carbon cloth, and can be achieved by coating or bonding D to the lower surface of the carbon fiber layer 112. 50 The microporous layer 111 is formed by fine particles of less than 5 μm or a network of fine fibers with a width of less than 10 μm, and the material of the fine particles or the network of fine fibers may include at least one selected from transition metals, aluminum, carbon and conductive polymers.

[0071] As described above, the contact layer 110 may include a microporous layer 111, which is formed by coating carbon paste onto the carbon fiber layer 112 (e.g., carbon paper, carbon cloth, etc.), followed by drying and heat treatment. The carbon paste forming the microporous layer 111 after drying and heat treatment can be obtained by mixing carbon powder, fluoropolymer, water, and alcohol. The fluoropolymer may be one or more selected from polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyvinyl chloride trifluoroethylene (PCTFE), tetrafluoroethylene-ethylene copolymer (ETFE), and polyfluorinated vinylidene (PVDF).

[0072] The carbon fiber layer 112 can be formed from carbon fibers. Carbon fibers (CF) can be fibrous carbon materials with a carbon content of 90% or more by mass. Specifically, carbon fibers can be fibers having a graphite structure obtained primarily through the pyrolysis of organic precursors (materials before carbonization). Furthermore, the carbon fiber layer 112 can be coated with a fluoropolymer resin.

[0073] As another embodiment, D can be coated or bonded to the lower surface of the conductive pressing plate 120 made of a rigid material. 50 The microporous layer 111 is formed as fine particles of about 5 μm or less, or as a network of fine fibers with a width of about 10 μm or less. Here, the material coated or bonded to the fine particles or the network of fine fibers to the first terminal portion 100 may include at least one selected from transition metals, aluminum, carbon, and conductive polymers.

[0074] like Figure 6As shown, the electrode resistance measuring device of this disclosure may further include a load body 150 stacked on the upper surface of the conductive pressing plate 120 to pressurize the secondary battery electrode 10. Multiple load bodies 150 may be provided. When measuring the through-plane resistance, the magnitude of the pressure applied to the secondary battery electrode 10 by the first terminal portion 100 may affect the measurement result. Therefore, it is necessary to apply an appropriate level of pressure to the secondary battery electrode 10, and the pressure applied to the secondary battery electrode 10 by the first terminal portion 100 can be adjusted by controlling the number of load bodies 150. The pressure applied to the secondary battery electrode 10 by the first terminal portion 100 is preferably about 0.01 kgf / cm². 2 To approximately 0.2 kgf / cm 2 If the pressure applied from the first terminal portion 100 to the secondary battery electrode 10 is less than approximately 0.01 kgf / cm². 2 If the contact resistance increases, the measurement accuracy may decrease, and if it exceeds approximately 0.2 kgf / cm², the contact resistance may increase and the measurement accuracy may decrease. 2 If the thickness of the secondary battery electrode 10 changes, or more precisely, the thickness of the electrode layer 11 changes, this may affect the measurement value.

[0075] The conductive pressing plate 120 and the load body 150 can be disc-shaped. For accurate measurement to be performed in the electrode resistance measuring device of this disclosure, it is important that the first terminal portion 100 is not tilted. Therefore, the conductive pressing plate 120 and the load body 150 can be configured in a disc shape so as to be non-anisotropic relative to a direction perpendicular to the vertical direction. The conductive pressing plate 120 can be provided with an alignment device (not shown) to align the center of the load body 150 with the center of the conductive pressing plate 120. The alignment device can be a protrusion, groove, mark, etc. A first wire 130 for the electrical connection between the conductive pressing plate 120 and the resistance measuring unit 300 can be attached to the side surface of the conductive pressing plate 120 so as not to interfere with the stacking of the load body 150. When the load body 150 is not present, the first wire 130 can be connected to the upper surface of the conductive pressing plate 120, such as... Figure 2 As shown.

[0076] In addition to this load body, a pressure applying machine can be used to adjust the pressure applied to the conductive press plate 120.

[0077] In another embodiment, the first terminal portion 100 may include a conductive pressing plate 120 made of a rigid material and a microporous layer 111 stacked on the lower surface of the conductive pressing plate 120. Specifically, D can be coated or bonded to the lower surface of the conductive pressing plate 120 made of a rigid material. 50The microporous layer 111 of the first terminal portion 100 is formed of fine particles of 5 μm or less or a network of fine fibers with a width of 10 μm or less, and the material of the fine particles or the network of fine fibers may include at least one selected from transition metals, aluminum, carbon, and conductive polymers. In other words, the slurry including the fine particles or the network of fine fibers can be directly coated onto the lower surface of the conductive pressing plate 120, which serves as a rigid support, and then dried and heat-treated to form the microporous layer 111.

[0078] The second terminal portion 200 may include a fixing member 210 electrically connected to the current collector 12, and a second wire 230 electrically connecting the fixing member 210 to the resistance measuring portion 300.

[0079] The fixing member 210 may include a clamp that makes surface or line contact with the current collector 12. The fixing member 210 may be configured as a conductive device. The fixing member 210 can press against both side surfaces of the current collector 12 with elastic force. For example, the fixing member 210 may include a first member contacting one side of the current collector 12 and a second member contacting the other side. The first member may be made of a conductive rigid material and make surface or line contact with the current collector 12, and an elastic pad may be mounted on the second member. Due to the elastic force, the first and second members can be in complete and tight contact with each other, with the current collector 12 located therebetween. Specifically, because the surface of the second member tapers along the shape of the first member, the current collector 12 can be in complete and tight contact with the first member.

[0080] The fixing member 210 can be arranged in a shape that extends along the length of the edge of the current collector 12, such as... Figure 4 and Figure 5 As shown. In other words, the fixing member 210 can simultaneously contact all long edges of the current collector 12 to minimize resistance errors that may occur during measurements based on the position of the second electrode portion.

[0081] In another embodiment, the fixing member 210 may be provided in the form of a resistance probe, such as an alligator clip.

[0082] The resistance measuring unit 300 may include a current source (not shown) that supplies input current between the first terminal 100 and the second terminal 200, and a voltmeter (not shown) that measures the voltage between the first terminal 100 and the second terminal 200. The input current is not limited to AC or DC and may vary depending on the purpose of the analysis. The resistance measuring unit 300 may be electrically connected to each of the first terminal 100 and the second terminal 200 via a first wire 130 and a second wire 230.

[0083] The first conductor 130 and the second conductor 230 may be conductors having a center made of conductive material and a surface exposed to insulating material.

[0084] The electrode resistance measuring device disclosed herein may further include a support plate 400 supporting the lower surface of the secondary battery electrode 10. The support plate 400 may have an upper surface formed as 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 formed of an insulating material.

[0085] Example 1

[0086] A cathode for a lithium secondary battery with electrode layers 11 formed on both surfaces of the current collector 12 is fabricated, the cathode having a size of 100 cm. 2 And measure the through-surface resistance of an electrode layer.

[0087] The conductive press plate 120 is prepared by coating copper material with gold, and the weight of the first terminal portion 100 is prepared to be 0.3 kg.

[0088] The area of ​​the lower surface of the first terminal portion 100 is 4.9 cm². 2 .

[0089] Sigrette 39 BC from SGL is used as contact layer 110, in which a microporous layer 111 is stacked on a carbon fiber layer 112.

[0090] A conductive paste layer 140 with a thickness of 20 μm is applied to the lower surface of the conductive pressing plate 120 to fix the contact layer 110.

[0091] The fixing member of the second terminal 200 is fixed to the uncoated portion of the current collector 12.

[0092] The first terminal portion 100 is disposed on the upper surface of the electrode layer 11, such that the outer end of the lower surface of the first terminal portion 100 is spaced about 2 cm from the boundary between the uncoated portion and the electrode layer 11.

[0093] The resistance measuring unit 300 is a Hioki BT3563 HiTESTER from Hioki. A 1kHz AC current is applied as the input current between the first terminal 100 and the second terminal 200.

[0094] The cathode of the lithium secondary battery is completely separated from the first terminal 100 and the second terminal 200, then reconnected, and the measurement is repeated three times.

[0095] Example 2

[0096] The through-plane resistance of the electrode layer opposite to that measured in Example 1 is measured.

[0097] The measurement conditions are the same as in Example 1.

[0098] The cathode of the lithium secondary battery is completely separated from the first terminal 100 and the second terminal 200, then reconnected, and the measurement is repeated three times.

[0099] Example 3

[0100] Except that the contact layer 110 and the conductive pressing plate 120 are not fixed with the conductive paste layer 140, the through-surface resistance of the same electrode layer is measured in the same manner as in Example 1.

[0101] Example 4

[0102] Except that the contact layer 110 and the conductive pressing plate 120 are not fixed with the conductive paste layer 140, the resistance of the relative electrode layers is measured in the same manner as in Example 3.

[0103] Comparative Example 1

[0104] Except that the contact layer or conductive paste layer is not formed on the lower surface of the first terminal portion 100 and the conductive pressing plate 120 is set as a single layer, the through-surface resistance of the same electrode layer is measured in the same manner as in Example 1.

[0105] Comparative Example 2

[0106] The surface resistance of the relative electrode layer was measured in the same manner as in Comparative Example 1.

[0107] Figure 7 This is a coordinate graph showing the resistance measurement results of Examples 1 to 4 and Comparative Examples 1 and 2. Figure 7 The resistance value shown is the average of three repeated measurements. Figure 7 As shown, in the through-surface resistance measurement, it can be seen that when a microporous layer 111 is present on the surface of the first terminal portion 100 that contacts the secondary battery electrode 10, the measured resistance value rapidly decreases to equal to or less than 1 / 10. Specifically, it can be seen that in the cases of Example 1 and Comparative Example 1, the measured resistance values ​​differ by approximately 25 times or more. Furthermore, it can be seen that the standard deviations of Examples 1 and 2 are significantly lower than those of Comparative Examples 1 and 2. This is because the contact resistance interfering with the measurement is minimized. In addition, the accuracy of Examples 1 to 4 and Comparative Examples 1 and 2 was calculated, and the results were 3.8%, 3.2%, 10.5%, 7.6%, 9.2%, and 12.7%, respectively. Accuracy was calculated as a percentage of the standard deviation value relative to the average value of the electrode resistance. Compared with Examples 3 and 4 and Comparative Examples 1 and 2, Examples 1 and 2 show excellent accuracy. This is because the contact resistance is minimized, and the stability of the device is enhanced by fixing the contact layer 110 using the conductive paste layer 140, thereby achieving excellent reproducibility.

[0108] Although embodiments according to this disclosure have been described above, they are merely illustrative, and those skilled in the art will understand that various variations and embodiments of equivalent scope can be derived from them. Therefore, the true technical scope of this disclosure should be defined by the appended claims.

[0109] <Explanation of Figure Markers>

[0110] 10…Secondary battery electrode 11…Electrode layer 12…Current collector 100…First terminal portion

[0111] 110…Contact layer 111…Microporous layer 112…Carbon fiber layer

[0112] 120…Conductive pressing plate 130…First wire 140…Conductive paste layer

[0113] 150…load body 200…second terminal 210…fixing member 230…second wire

[0114] 300… Resistance measuring section 400… Support plate

Claims

1. An electrode resistance measuring device for measuring the resistance of an electrode, the electrode comprising a current collector and an electrode layer stacked on one or both surfaces of the current collector, the electrode resistance measuring device comprising: The first terminal portion is electrically connected to the exposed surface of the electrode layer by directly contacting the exposed surface of the electrode layer; The second terminal portion is electrically connected to the current collector by direct contact; as well as The resistance measuring unit is configured to measure the 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 formed of a microporous layer, and The second terminal portion includes a fixing member that is fixed to the uncoated portion of the current collector.

2. The electrode resistance measuring device according to claim 1, wherein The material of the microporous layer includes at least one selected from carbon, conductive metals, and conductive polymers.

3. The electrode resistance measuring device according to claim 1, wherein, By D 50 The microporous layer of the first terminal portion is formed by coating or bonding fine particles of less than 5 μm or a network of fine fibers with a width of less than 10 μm to the lower surface of a conductive pressing plate made of a rigid material. The material of the fine particles or the fine fiber network includes at least one selected from transition metals, aluminum, carbon, and conductive polymers.

4. The electrode resistance measuring device according to claim 1, wherein, The first terminal portion includes: A conductive pressing plate, the conductive pressing plate being made of a conductive material, and the conductive pressing plate having a lower surface, the lower surface of the conductive pressing plate being formed as a plane perpendicular to the vertical direction; and A contact layer, the contact layer being fixed to the lower surface of the conductive pressing plate, and The contact layer includes the microporous layer, and The contact layer and the lower surface of the conductive pressing plate are fixed by a conductive paste layer.

5. The electrode resistance measuring device according to claim 4, wherein, The material of the conductive pressing plate includes at least one selected from 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 electrode resistance measuring device according to claim 6, wherein, The carbon fiber layer is adhered to the lower surface of the conductive pressing plate via the conductive paste layer, and The microporous layer is stacked on the lower surface of the carbon fiber layer.

8. The electrode resistance measuring device according to claim 7, wherein, The conductive paste layer is formed by coating and drying a mixture of conductive particles, adhesive, and solvent. The conductive particles are made of at least one material selected from carbon black, graphite, CNTs, graphene, transition metals, and aluminum. The size of the conductive particles is D 50 is 20 μm or less.

9. The electrode resistance measuring device according to claim 8, wherein, The conductive paste layer is formed to have a thickness of 10 μm 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 μm to 150 μm.

12. The electrode resistance measuring device according to claim 6, wherein, The carbon fiber layer includes carbon paper or carbon cloth. By D 50 The microporous layer is formed by coating or bonding fine particles smaller than 5 μm or a network of fine fibers with a width of less than 10 μm to the lower surface of the carbon fiber layer, and The material of the fine particles or the fine fiber network includes at least one selected from transition metals, aluminum, carbon, and conductive polymers.

13. The electrode resistance measuring device according to claim 1, wherein, The fixing component includes a clamp that contacts or lines with the current collector surface, and The fixing component is made of a conductive material.

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

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