Diagnostic device for dry electrode mixtures

Abstract

A diagnostic device for a dry electrode mixture includes a frame and a measurer disposed in the frame and configured to measure conductivity and flow characteristics of the prepared dry electrode mixture. The dry electrode mixture includes a powder mixture including an electrode active material, a conductive material, and a binder. The diagnostic device further includes a controller configured to evaluate characteristics of the dry electrode mixture based on the conductivity and flow characteristics measured by the measurer.

Description

Technical Field

[0001] The present invention relates to a dry electrode mixture for a battery. More particularly, the present invention relates to a device for diagnosing the state of the dry electrode mixture. Background Art

[0002] In recent years, the application of rechargeable secondary batteries is expanding to various fields from small electronic devices to large energy storage systems. In particular, due to the rapid growth of the electric vehicle market, the research and development of secondary batteries is being actively carried out.

[0003] Electrodes for secondary batteries are usually manufactured by a wet process. In a wet process, a slurry is manufactured by dissolving an electrode active material, a binder, and a conductive material contained in the electrode in a solvent. However, a dry process that can increase the energy density of the electrode compared to a wet process that does not use a solvent required in a wet process has recently been introduced.

[0004] In the dry process of the electrode, a mixture is prepared by mixing electrode materials, and a dry electrode film is formed by a film forming process by pressing or calendering. Then, the electrode is manufactured by bonding the formed dry electrode film to a current collector.

[0005] The manufacture of electrodes by dry process is in the early or initial stage of technology development, and therefore, there is no technology related to quality assessment. Therefore, when a defect is found in the final stage of the manufacturing process of the electrode, the manufacturing process should return to the first stage to solve the occurrence of the defect. In addition, it takes a lot of time and cost to determine the cause of the defect. Therefore, in order to ensure the quality of the manufactured electrode, an evaluation technology for evaluating the quality of the mixture before the film forming process is required in terms of time and cost.

[0006] The above information disclosed in this Background section is only for enhancing understanding of the background of the present invention. Therefore, the Background section may contain information that does not constitute the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0007] The present invention provides a diagnostic device for a dry electrode mixture, which can effectively evaluate the dry electrode mixture.

[0008] In one aspect of the present invention, a diagnostic device for a dry electrode mixture includes: a frame; and a measurer, the measurer being disposed in the frame and configured to measure the conductivity and flow characteristics of a dry electrode mixture prepared as a powder mixture. The powder mixture contains an electrode active material, a conductive material, and a binder. The diagnostic device also includes a controller configured to evaluate the characteristics of the dry electrode mixture based on the conductivity and the flow characteristics measured by the measurer.

[0009] Other aspects and embodiments of the invention are discussed below.

[0010] The above and other features of the invention are discussed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The above and other features of the present invention shall now be described in detail with reference to certain embodiments of the invention, which are shown in the accompanying drawings, which are given hereinafter only by way of illustration and therefore do not limit the present invention, and in which:

[0012] Figure 1 is a view showing a diagnostic device for a dry electrode mixture according to one embodiment of the present invention;

[0013] Figure 2 is a view showing a holder and a housing of a diagnostic device according to an embodiment of the present invention;

[0014] Figure 3 is a view showing a holder of a diagnostic device according to an embodiment of the present invention;

[0015] Figure 4 is a view showing a housing of a diagnostic device according to an embodiment of the present invention;

[0016] Figure 5 is a view showing a diagnostic device according to one embodiment of the present invention;

[0017] Figure 6 is a graph showing shear stress measured under a certain normal stress in a diagnostic device according to an embodiment of the present invention;

[0018] Figure 7 is a view showing a support protrusion of a diagnostic device according to an embodiment of the present invention;

[0019] Figure 8 is a block diagram showing some elements of a diagnostic device according to one embodiment of the present invention;

[0020] Fig. 9 is a view showing a flattener of a diagnostic device according to an embodiment of the present invention; and

[0021] Fig.10 is a flowchart showing the operation of the diagnostic apparatus according to one embodiment of the present invention.

[0022] It should be understood that the accompanying drawings are not necessarily drawn to scale, and that they present a somewhat simplified representation of various features illustrating the basic principles of the invention. The specific design features of the present invention disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes should be determined in part by the specific intended application and use environment.

[0023] In the drawings, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. DETAILED DESCRIPTION

[0024] The specific structure or function description in the embodiment of the present invention set forth in the following description should be given to describe the embodiment of the present invention. In addition, the present invention can be embodied in many alternative forms. In addition, it should be understood that the present invention should not be construed as being limited to the embodiment set forth herein, and the embodiment of the present invention is provided only to fully disclose the present invention and to be encompassed in the modification, equivalent or alternative within the scope of the present invention and the technical scope.

[0025] In the following description of the embodiments, terms such as "first" and "second" are used only to describe various elements, and these elements should not be interpreted as being limited by these terms. These terms are used only to distinguish one element from other elements. For example, without departing from the scope of the present invention, a first element described below may be referred to as a second element, and similarly, a second element described below may be referred to as a first element.

[0026] When an element or layer is referred to as being "connected to" or "coupled to" another element or layer, it may be directly connected or coupled to the other element or layer, or there may be intervening elements or layers. Conversely, when an element or layer is referred to as being "directly connected to" or "directly coupled to" another element or layer, there may not be intervening elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner, for example, "between" versus "directly between," "adjacent" versus "directly adjacent," etc.

[0027] Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts. The terms used herein are for the purpose of describing specific embodiments only and are not intended to be limiting. As used herein, singular forms may also be intended to include plural forms, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having" are inclusive and thus specify the presence of the features, integers, operations, elements, components, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, integers, operations, elements, components, and / or combinations thereof.

[0028] When a component, device, element, etc. of the present invention is described as having a purpose or performing an operation, function, etc., the component, device or element should be considered herein as "configured to" satisfy the purpose or perform the operation or function.

[0029] Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below.

[0030] The dry electrode can be made from a dry electrode mixture and a current collector. The dry electrode mixture can be placed in a film forming device including a film forming device. The dry electrode mixture can be formed into a dry electrode film by a film forming process, and the dry electrode can be made by bonding or laminating the dry electrode film to the current collector or bonding or laminating it on the current collector. The formation of the dry electrode film and the lamination of the dry electrode film on the current collector can be carried out in one device, or can also be carried out in separate devices.

[0031] The dry electrode mixture is a mixture of an electrode active material, a conductive material and a binder. The dry electrode mixture is prepared by mixing the electrode active material, the conductive material and the binder with a mixer. As a non-limiting example, the dry electrode mixture can be manufactured by using a rotating high shear mixer or a pneumatic mixer using air. The dispersion conditions can be changed by the dispersion speed (i.e., rotation speed) and dispersion time (i.e., operation time) of this mixer.

[0032] According to the present invention, the dry electrode can be a cathode or an anode.

[0033] In some embodiments, when manufacturing a cathode, the electrode active material includes a cathode active material. As a non-limiting example, the cathode active material may include nickel manganese cobalt oxide (NMC), lithium iron phosphate (LFP), lithium cobalt oxide (LCO), or sulfur. For example, the cathode active material may be: lithium cobalt oxide (LiCoO 2 ) or lithium nickel oxide (LiNiO 2 ) or a layered compound in which a part of the layered compound is substituted by one or more transition metals; a layered compound having the chemical formula Li 1+x Mn 2-x O 4 (x=1 to 0.33) represented by a lithium manganese compound, such as LiMnO 3 、LiMn 2 O 3 or LiMnO 2 ; Lithium copper oxides, such as Li 2 CuO 2 ; Vanadium oxides, such as LiV 3 O 8 、LiFe 3 O 4 、V 2 O5 Cu 2 V 2 O 7 ; By chemical formula LiNi 1-x M x O 2 (wherein, M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3) represented by Ni-type lithium nickel oxide; represented by the chemical formula LiMn 2-x M x O 2 (wherein M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1) or the chemical formula Li 2 Mn 3 MO 8 (wherein M = Fe, Co, Ni, Cu or Zn) represented by a lithium manganese composite oxide; LiMn wherein a portion of Li in the chemical formula is replaced by an alkaline earth metal ion 2 O 4 ; Chemical formula LiMPO 4 (wherein M=Fe, Co, Ni or Mn) represented by lithium metal phosphate; disulfide; Fe 2 (MoO 4 ) 3 , but not limited to this.

[0034] In some embodiments, when manufacturing an anode, the electrode active material includes an anode active material. As a non-limiting example, the anode active material may include graphite or silicon. For example, the anode active material may be: carbon, such as hard carbon or graphite carbon; metal composite oxide, such as Li x Fe 2 O 3 (0≤x≤1), Li x WO 2 (0≤x≤1) or Sn x Me 1-x Me' y O z (wherein Me = Mn, Fe, Pb or Ge; Me′ = Al, B, P, Si, an element of Group I, II or III in the periodic table, or a halogen element; 0 < x ≤ 1, 1 ≤ y ≤ 3, 1 ≤ z ≤ 8); lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; silicon-based oxide, such as SiO, SiO / C or SiO 2 ; Metal oxides, such as SnO, SnO 2 、PbO、PbO 2 , Pb 2 O 3 , Pb 3 O 4 , Sb2 O 3 , Sb 2 O 4 , Sb 2 O 5 、GeO、GeO 2 、Bi 2 O 3 、Bi 2 O 4 Or Bi 2 O 5 ; Conductive polymers such as polyacetylene; Li-Co-Ni based materials.

[0035] The conductive material may include a carbonaceous material. For example, the conductive material may include one of various carbonaceous materials, such as super P, Ketjen black, single-walled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs). In addition, the dry electrode mixture prepared for the manufacture of a dry electrode for an all-solid-state battery may further include a polyethylene oxide (PEO)-based polymer, an oxide-based solid electrolyte and / or a sulfide-based solid electrolyte.

[0036] The binder may include a material having a CF bond, ie, including carbon and fluorine, such as polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF). The binder may also include styrene-butadiene rubber (SBR) / carboxymethyl cellulose (CMC) or polyacrylonitrile (PAN).

[0037] The inventors of the present invention have submitted a patent application entitled “Method for evaluating a dry electrode mixture by measuring the flow properties of the dry electrode mixture” (Korean Patent Application No. 10-2023-0021097, filing date: February 17, 2023) and a patent application entitled “Method for evaluating a dry electrode mixture by measuring the electrical conductivity of the dry electrode mixture” (Korean Patent Application No. 10-2023-0055862, filing date: April 28, 2023).

[0038] In the previous patent application, the flow characteristics of the manufactured dry electrode mixture were measured. The flow characteristics measurement can be performed based on ASTM D6128, which is a standard of the American Society for Testing and Materials (ASTM). In such an evaluation method, a shear stress is applied to a specified amount of dry electrode mixture, and the internal stress of the dry electrode mixture flowing in a state of equilibrium or steady state is measured. The internal stress of the dry electrode mixture in equilibrium represents a force distribution that varies depending on the friction and cohesion between the mixture particles, and the flow index of the mixture can be quantified based on this measurement.

[0039] In more detail, based on ASTM D6128, shear stress is applied to the dry electrode mixture by operating a blade while applying pressure to the dry electrode mixture from above. The blade contacts the powder of the dry electrode mixture, and a slight shear stress is applied to the dry electrode mixture by applying a slight pressure to the powder of the dry electrode mixture from the moment the blade contacts the powder of the dry electrode mixture. According to the characteristics of the powder, at a specified time point, collapse between powder particles occurs in the dry electrode mixture, and the stress of the powder at this time point is measured as internal stress data. When collapse occurs, shear stress is applied to the powder of the dry electrode mixture by applying a higher pressure thereto, and measurement is performed again. The flow index of the powder is obtained by differentiating the measured internal stress data with the applied shear stress.

[0040] The flow index obtained by the flow property evaluation method varies according to the proportion of the electrode materials (i.e., electrode active materials, conductive materials, and adhesives) in the mixture. In addition, even in a mixture with the same proportion of electrode materials, the flow index varies according to the degree of mixing of the electrode materials or the mixing or dispersion conditions. When the adhesive or conductive material is unevenly dispersed and thus concentrated in a specific space, the shear stress used for mixing is insufficient or excessive, and therefore, the degree of mixing of the mixture may vary. Therefore, when the dispersion and mixing degree of the mixture for forming the dry electrode film are obtained, the difference in flow properties with the mixture having different mixing degrees can be determined.

[0041] Therefore, the quality or properties of the finished mixture can be predicted by the flow characteristics evaluation method. The properties of the mixture of electrode materials can indicate the probability of film formation through the film forming process.

[0042] Next, determine whether the flow index of the corresponding mixture obtained is within the prescribed flow index range. According to the present invention, the prescribed flow index becomes a reference in the evaluation of the flow characteristics of the mixture. Specifically, when the target mixture to be evaluated has a prescribed flow index, it can be predicted that the mixture is formed into a normal film through a film forming process. In addition, a prescribed flow index range is set while taking errors into consideration. In addition, when the flow index of the target mixture to be evaluated is within the prescribed flow index range, it is predicted that the mixture is formed into a normal film through a film forming process. The prescribed flow index can be obtained by measuring the flow index of each dry electrode mixture having different proportions of electrode materials and mixing conditions and testing whether each dry electrode mixture is formed into a film. The prescribed flow index range is determined to be 0.50 to 0.70 in the case of the cathode and 0.60 to 0.80 in the case of the anode.

[0043] In the latter patent application (Korean Patent Application No. 10-2023-0055862, Application Date: April 28, 2023), the conductivity of the dry electrode mixture can be measured. In addition, the proportion of materials forming the dry electrode mixture, the degree of dispersion of the materials, and the degree of fibrillation of the binder can be evaluated based on the measured conductivity.

[0044] The fibrillation of the binder can indicate that the spherical particles of the binder are changed into a fibril structure by applying energy to the dry electrode mixture during the mixing process of the dry electrode mixture. Specifically, the binder includes primary particles and secondary particles. Small binder particles with a size of about 500 nanometers (nm) or less can be referred to as primary particles, while particles with a size of about hundreds of nanometers and formed by the aggregation of primary particles can be referred to as secondary particles. When energy is applied to the dry electrode mixture during the mixing process of the dry electrode mixture, the secondary particles are separated into primary particles, and the primary particles are changed from a spherical structure to a fine fiber or fibril structure by high shear. This phenomenon is called the fibrillation of the binder.

[0045] Due to this fibrillation process of the adhesive, the fibril structure can have a long length or a short length, or can be thick or thin. The extent of this fibril structure can be referred to as the fibrillation degree of the adhesive. As mentioned above, an appropriate fibrillation degree of the adhesive is required.

[0046] The fibrillation degree of the binder may depend on the dispersion conditions of a specific dry electrode mixture, such as dispersion speed or dispersion time. For example, the fibrillation degree of the binder generally increases with the dispersion speed or dispersion time of a given dry electrode mixture. In addition, as the fibrillation of the binder proceeds, the conductivity of the dry electrode mixture increases, and eventually converges to a certain level, and then decreases. As the fibrillation of the binder proceeds, the fibril structure is spread thinly, thereby ensuring the electron transfer path, which causes the resistance between the particles of the dry electrode mixture to decrease, and the conductivity of the dry electrode mixture to increase. However, as the fibrillation of the binder proceeds excessively, the fibril structure is coated on the electrode particles, so the resistance increases, and the conductivity of the dry electrode mixture decreases. In addition, a film-forming process for forming the dry electrode mixture into a thin film should be carried out so that the fibrillated dry electrode mixture is bonded to a substrate. In this regard, a fibrillated dry electrode mixture having a fibril structure of a specific thickness or greater thickness is advantageous in film forming. In other words, excessive fibrillation is disadvantageous in film forming. Taking these characteristics into consideration, the appropriate fibrillation dispersion speed and dispersion time for each dry electrode mixture can be defined.

[0047] As described above, the dry electrode mixture includes components including electrode active materials, conductive materials and binders. Each component has a different inherent conductivity. In addition, since the agglomeration size of the binder particles, the dispersion degree of the binder, etc., vary according to the fibrillation degree of the binder, the conductivity of the dry electrode mixture varies according to the shape or density of the binder. The present invention is configured to evaluate the dry electrode mixture using these characteristics of the dry electrode mixture.

[0048] The conductivity of the dry electrode mixture is measured when a specified or variable pressure is applied to the dry electrode mixture. The dry electrode mixture is fixed to have a volume with an area of ​​S and a height of H, or has a mass of w (S, H and w are specified values). When a specified pressure is applied to the top of the dry electrode mixture having the above-mentioned specific amount, the conductivity of the dry electrode mixture is measured by a probe. The conductivity (Siemens / cm) depending on the pressure (kilopascals (kPa) or megapascals (MPa)) is measured, and the measured data can be used to evaluate the dry electrode mixture, for example, to determine whether the fibrillation of the adhesive is suitable.

[0049] Whether the fibrillation of the binder in the dry electrode mixture to be measured is suitable can be determined by comparing the measured conductivity with the pre-collected information. The pre-collected information includes the ratio of the components in the various dry electrode mixtures, the dispersion speed, the dispersion time, the conductivity of the dry electrode mixture, and whether the fibrillation of the binder in each dry electrode mixture is suitable. Therefore, the ratio of the components of the dry electrode mixture to be measured can be estimated by comparing the measured conductivity with the pre-collected information. In addition, whether the fibrillation of the binder in the dry electrode mixture is suitable can be determined based on the estimated ratio of the components in the dry electrode mixture.

[0050] The present invention provides a diagnostic device for a dry electrode mixture, which can simultaneously perform both evaluation of the flow characteristics of the dry electrode mixture useful for evaluating the dry electrode mixture and measurement of the conductivity. According to the present invention, there is no need for separate devices configured to measure these two characteristics individually. As a result, the time and cost required for measurement can be reduced, and the analysis efficiency can be improved.

[0051] The diagnostic device 100 for a dry electrode mixture can simultaneously perform an evaluation of the flow characteristics and a measurement of the conductivity of the dry electrode mixture.

[0052] like Figure 1As shown, according to one embodiment of the present invention, the diagnostic device 100 may include a frame 200 and a measurer 30. The measurer 30 includes a storage portion 300, a driver 400 and a moving portion 500. The measurer 30 is configured to measure the flow characteristics and conductivity of the dry electrode mixture disposed in the frame 200. The storage portion 300 may store the dry electrode mixture as a target object to be measured. The driver 400 and the moving portion 500 may have a structure configured to move the storage portion 300 and may provide a driving force to measure the flow characteristics and conductivity of the dry electrode mixture stored in the storage portion 300 and evaluate the dry electrode mixture.

[0053] refer to Figure 2 The storage part 300 includes a holder 310 and a housing 320. The holder 310 is configured to store the dry electrode mixture to be evaluated. The housing 320 is configured to cover the holder 310 so that a series of measurement operations are performed in the housing 320.

[0054] like Figure 3 As shown, the holder 310 may include a plurality of recesses 312 recessed from the inner surface of the holder 310. The recesses 312 may be formed on the inner bottom surface of the holder 310 in a specified pattern. The pattern shown is only an example, and the recesses 312 may be formed in other patterns. When the flow characteristics of the dry electrode mixture are measured by the diagnostic device 100, the recesses 312 function to prevent the dry electrode mixture from easily sliding due to the rotation of the blade 322.

[0055] refer to Figure 4 and Figure 5 , elements configured to perform evaluation are disposed in a housing 320. A rotatable blade 322 is disposed in the housing 320. A rotational force may be applied to the dry electrode mixture in the holder 310 by the rotation of the blade 322.

[0056] The housing 320 includes a probe 326 disposed on a shaft 324 as a central portion of the blade 322. The probe 326 can contact the dry electrode mixture disposed in the holder 310, and can measure the conductivity of the dry electrode mixture. As a non-limiting example, the probe 326 can be a four-point probe. In particular, the conductivity of the dry electrode mixture can be measured in a state where a normal stress σ is applied to the dry electrode mixture by the descent of the moving part 500. The shear stress τ and the normal stress σ can be changed by the rotation speed of the blade 322 and the movement of the moving part 500 or the extrusion force generated by the moving part 500 according to the desired setting.

[0057] refer to Figure 6, when the moving part 500 and the housing 320 installed below the moving part 500 are lowered, the flow characteristics and conductivity of the dry electrode mixture are measured. The normal stress σ is applied to the dry electrode mixture by lowering the moving part 500 toward the dry electrode mixture, and the shear stress τ is applied to the dry electrode by rotating the blade 322, thereby measuring the flow characteristics of the dry electrode mixture. The flow characteristics of the dry electrode mixture are measured by applying the shear stress τ several times under the same normal stress σ, and at this time, not only the flow characteristics of the dry electrode mixture but also the conductivity of the dry electrode mixture can be measured by the probe 326 under the normal stress σ shown. In one example, the conductivity of the dry electrode mixture can be measured in a state where only the normal stress σ is applied to the dry electrode mixture, that is, before the shear stress τ is applied to the dry electrode mixture.

[0058] In some embodiments, a portion of the housing 320 where the blade 322 is mounted may be separated from the rest of the housing 320. In this case, the corresponding portion of the housing 320 may be easily cleaned.

[0059] The diagnostic device 100 may further include a balance 330. The balance 330 is disposed at the bottom of the frame 200. The balance 330 can measure the mass of the dry electrode mixture in the holder 310 only when the holder 310 is disposed at the upper end of the balance 330. The mass of the dry electrode mixture can be measured before the diagnostic device 100 starts to perform the evaluation test, and may not be measured thereafter. To this end, a support protrusion 220 formed as a protrusion may be provided on the bottom of the frame 200. The length of the balance 330 may be smaller than the length of the bottom surface of the holder 310. The support protrusion 220 may be a plurality of protrusions spaced apart from each other in the circumferential direction of the frame 200, or an annular protrusion may be continuously formed in the circumferential direction of the frame 200. As Figure 7 As shown, after initially measuring the mass of the dry electrode mixture, the support protrusion 220 may protrude from the frame 200 to separate the balance 330 and the holder 310 from each other. The flow characteristics and conductivity of the dry electrode mixture may be measured in a state where the holder 310 is supported by the support protrusion 220. In some embodiments, the support protrusion 220 may be configured to be fixed to support the holder 310, and the balance 330 may be configured to be raised to measure the mass of the dry electrode mixture and lowered after the mass measurement.

[0060] The driver 400 may provide a driving force to the storage portion 300. For example, the driver 400 may raise or lower the moving portion 500, and thus may raise or lower the housing 320 connected to the moving portion 500. In addition, the driver 400 may rotate the moving portion 500, and thus may rotate the housing 320 and the blade 322 disposed therein. To this end, the driver 400 may include, for example, a cylinder and a motor.

[0061] The moving part 500 may be raised or lowered, and may be rotated by the driver 400. The pressure applied to the dry electrode mixture in the holder 310 may be adjusted by raising and lowering the moving part 500. In addition, the shear stress applied to the dry electrode mixture in the holder 310 may be changed when the pressure and the number of revolutions (e.g., revolutions per minute) of the moving part 500 are changed.

[0062] The driver 400 can measure the internal stress of the dry electrode mixture. As described above, when the dry electrode mixture collapses when shear stress is applied to the dry electrode mixture in an extruded state, the flow characteristics of the dry electrode mixture are calculated based on the shear stress, i.e., the internal stress of the dry electrode mixture. Since the normal stress σ and the shear stress τ are applied to the dry electrode mixture by the driver 400 via the moving part 500, the shear stress τ applied to the dry electrode mixture by the driver 400 at the time point when the dry electrode mixture collapses can be collected as internal stress. In other words, based on the drive of the driver 400, the collected internal stress can be considered as the resistance of the dry electrode mixture.

[0063] refer to Figure 8 The controller 600 is configured to control the operation of the diagnostic apparatus 100. For example, the controller 600 may control the operation of the driver 400. In addition, the controller 600 may receive the value measured by the probe 326, and may receive the internal stress data.

[0064] Specifically, the controller 600 may collect information about the force (kilonewton, kN) applied by the diagnostic device 100, the conductivity (S / cm), the applied shear stress (kPa), the internal stress to the applied shear stress (kPa), and the density (kilograms per cubic meter, kg / m 3 ) data.

[0065] More specifically, the diagnostic device 100 may measure data, and the measured data may be transmitted to the controller 600. As an example, the data of the diagnostic device 100 includes a density (kg / m2) of a normal stress σ (kPa) applied by the driver 400. 3 ). The mass value measured by the balance 330 can be used as the mass (kg). As another example, the data of the diagnostic device 100 includes measurements related to conductivity. The measurements related to conductivity may include at least one of resistance (ohm, Ω) to normal stress σ (kPa), volume resistivity (ohm-cm, Ω·cm) to normal stress σ (kP), or conductivity (S / cm) to normal stress σ (kPa). As yet another example, the data of the diagnostic device 100 includes measurements related to flow characteristics. The measurements related to flow characteristics may include apparent density (kg / m 3), at least one of an effective internal friction angle (°) relative to an applied shear stress τ, or an internal stress (Pa) to an applied shear stress τ. The effective angle may be calculated as a ratio of the shear stress τ applied to the dry electrode mixture to the normal stress σ. The effective internal friction angle is the same as the maximum value before the dry electrode mixture collapses. The controller 600 may calculate the flow index by differentiating the internal stress relative to the applied shear stress τ.

[0066] The controller 600 includes a processor and a memory. The memory stores commands executable by the processor, specified flow indexes, pre-collected information related to conductivity, etc. The commands may include commands configured to perform operations of the processor and / or operations of various elements of the processor. The memory may be a volatile or non-volatile memory, and the processor may execute commands stored in the memory. The processor may also execute computer-readable codes and commands stored in the memory.

[0067] refer to Fig. 9 and Fig.10 , the operation of the diagnostic apparatus 100 according to the present invention is described below.

[0068] First, the film forming device 10 distributes the dry electrode mixture to be evaluated to the holder 310 (S1000). The dry electrode mixture distributed to the holder 310 is flattened by the flattener 700, as shown in FIG. Fig. 9 The leveler 700 may include a tray 710 and a cutter 720. The cutter 720 is mounted on the tray 710 and is configured to be rotatable relative to the tray 710. The dry electrode mixture may be leveled by the scraping motion of the cutter 720.

[0069] The holder 310 is set on the balance 330 in the diagnostic device 100, and the mass of the dry electrode mixture accommodated in the holder 310 is measured (S1200). After the mass measurement, the support protrusion 220 may protrude to support the holder 310, and then the measurement of the mass of the dry electrode mixture may be stopped. Otherwise, the support protrusion 220 may be configured to be fixed, and the balance 330 may be raised to measure the mass of the dry electrode mixture, and then may be lowered after the mass measurement.

[0070] The controller 600 operates the driver 400 and the mobile part 500 to perform the evaluation of the dry electrode mixture (S1300 and S1400). The diameter of the housing 320 is smaller than the diameter of the retainer 310, so the blade 322 and the shaft 324 can contact the dry electrode mixture in the retainer 310 without interfering with the retainer 310. The mobile part 500 is lowered by the operation of the driver 400, and thus applies pressure to the dry electrode mixture. The conductivity of the dry electrode mixture is measured by the probe 326. In addition, the blade 322 rotates, thereby applying shear stress to the dry electrode mixture, and the flow characteristics of the dry electrode mixture (that is, the internal stress of the dry electrode mixture at the time point when the mixture collapses due to the applied shear stress) are measured. After the flow characteristics measurement has been completed, the rotation of the blade 322 can be stopped, and the conductivity of the dry electrode mixture can be measured again by the probe 326. When such a first measurement cycle has been completed, the flow characteristics of the dry electrode mixture are measured again. In other words, a normal stress greater than that in the first measurement cycle is applied to the dry electrode mixture, and the internal stress of the dry electrode mixture at the time point when the dry electrode mixture collapses is measured when shear stress is applied to the dry electrode mixture under the corresponding normal stress. Such a process is repeated a specified number of times when the normal stress is increased, so that data related to the flow characteristics can be obtained. In addition, in some embodiments, the conductivity of the dry electrode mixture is measured whenever the normal stress changes. In some embodiments, the conductivity of the dry electrode mixture is measured before the shear stress is applied, after the shear stress is applied, or before and after the shear stress is applied. In addition, in some embodiments, the conductivity of the dry electrode mixture can be measured in a state where shear stress is applied to the dry electrode mixture.

[0071] After the conductivity and flow characteristics are measured, the housing 320 can be raised by the driver 400 (S1500), and the measured flow characteristics and conductivity can be sent to the controller 600 for analysis (S1600). In other words, the controller 600 can calculate the flow index based on the stress data when the dry electrode mixture collapses due to the applied shear stress, and can determine the film forming probability of the corresponding dry electrode mixture by determining whether the calculated flow index is within the specified flow index range. In addition, the controller 600 can predict the proportion of the components of the corresponding dry electrode mixture and determine whether the binder is fibrillated by comparing the measured conductivity with the pre-collected information.

[0072] The flow characteristics and the conductivity of the dry electrode mixture are measured under the condition that pressure is applied to the dry electrode mixture from the top of the dry electrode mixture. As a result, the measurement of the flow characteristics and the measurement of the conductivity can be performed simultaneously. Therefore, according to the present invention, the time spent on measuring the flow characteristics and the conductivity of the dry electrode mixture can be reduced, and the measurement procedure can be simplified.

[0073] As apparent from the above description, the present invention provides a diagnostic device for a dry electrode mixture that can effectively evaluate the dry electrode mixture.

[0074] The invention has been described in detail with reference to the embodiments thereof. However, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention as defined by the appended claims and their equivalents.

Claims

1. A diagnostic device for a dry electrode mixture, in, include: frame; a measuring device disposed in the frame and configured to measure conductivity and flow characteristics of a prepared dry electrode mixture, the dry electrode mixture comprising a powder mixture of an electrode active material, a conductive material, and a binder; and A controller is configured to evaluate a property of the dry electrode mixture based on the conductivity and the flow property measured by the meter.

2. The diagnostic device according to claim 1, wherein: The measuring device comprises: a holder configured to receive the dry electrode mixture; and a housing configured to apply shear stress to the dry electrode mixture in the holder when pressure is applied to the dry electrode mixture in the holder, The housing includes a probe configured to measure the conductivity of the dry electrode mixture.

3. The diagnostic device according to claim 2, wherein: Further including: a moving portion connected to the housing and configured to move and rotate the housing relative to the frame; and A driver is configured to provide a moving force and a rotational force to the moving part.

4. The diagnostic device according to claim 3, wherein: The housing includes a blade rotatably disposed in the housing.

5. The diagnostic device according to claim 4, wherein: The probe is disposed on the shaft of the blade in the housing.

6. The diagnostic device according to claim 1, wherein: Further including: A balance is disposed at a bottom of the frame and is configured to measure the mass of the dry electrode mixture.

7. The diagnostic device according to claim 6, wherein: The frame includes a support protrusion configured to protrude from the frame, the support protrusion configured to support a holder disposed on the balance at a distance from the balance.

8. The diagnostic device according to claim 1, wherein: The controller is further configured as follows: comparing the measured flow characteristic with a specified flow index; When the flow characteristics are within the range of the prescribed flow index, it is determined that the dry electrode mixture can be formed into a film.

9. The diagnostic device according to claim 8, wherein: The controller is further configured as follows: acquiring the internal stress of the dry electrode mixture at a time point when the dry electrode mixture collapses when the shear stress applied to the dry electrode mixture is increased in a state where a specified normal stress is applied to the dry electrode mixture; The flow properties are calculated by differentiating the internal stress with respect to the shear stress.

10. The diagnostic device according to claim 1, wherein: The controller is further configured to predict a ratio of components of the dry electrode mixture by comparing the measured conductivity with pre-collected data.

11. The diagnostic device according to claim 10, wherein: The pre-collected data includes the ratio of components in each of the plurality of dry electrode mixtures, the dispersion conditions when each of the dry electrode mixtures is manufactured, the conductivity of each of the dry electrode mixtures, and the degree of fibrillation of the binder in each of the dry electrode mixtures.

12. The diagnostic device according to claim 11, wherein: The controller is further configured to predict the ratio of the components in the dry electrode mixture and predict the degree of fibrillation of the binder in the dry electrode mixture based on data of the dry electrode mixture having the same conductivity as the measured conductivity in the pre-collected data.

13. The diagnostic device according to claim 2, wherein: Further including: A leveler is configured to be separated from the frame and to level the dry electrode mixture disposed in the holder.

14. The diagnostic device according to claim 13, wherein: The leveler further comprises: a tray configured to have a larger cross-section than the holder, the holder being disposed on the tray; and A cutter is mounted to the tray and is configured to flatten the dry electrode mix in the holder by rotating.

15. The diagnostic device according to claim 2, wherein: The retainer further includes a plurality of recesses recessed from an inner surface of the retainer.

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