Title of Invention: Pressurized Membrane Resistance Measurement Apparatus and Measurement Method
technical field
[One]
The present invention relates to an apparatus and method for measuring the resistance of a pressurized separator.
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0132213 on October 23, 2019, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification.
background
[3]
As the price of energy sources increases due to the depletion of fossil fuels and interest in environmental pollution is increased, the demand for eco-friendly alternative energy sources is increasing. In particular, as technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing. Regarding the shape of the secondary battery, the demand for the pouch-type secondary battery is high in that it can be applied to mobile products such as mobile phones with a thin thickness.
[4]
This pouch-type secondary battery has a structure in which an electrode assembly is embedded in a pouch-type battery case formed of an aluminum laminate sheet. Specifically, in the pouch-type secondary battery, a stack-type or stack-folding-type electrode assembly in which a positive electrode, a separator, and a negative electrode are sequentially stacked is accommodated in the battery case. The positive electrode and the negative electrode are electrically connected to each other by electrode tabs, and the electrode tabs are connected to an electrode lead drawn out. After the electrode assembly to which the electrode tab and the electrode lead are connected is accommodated in a pouch-shaped battery case, electrolyte is injected, and the battery case is sealed with a part of the electrode lead exposed to the outside to assemble a secondary battery.
[5]
Conventionally, in order to evaluate the resistance characteristics of such a separator, the insulation properties of the separator itself were measured. Specifically, the dielectric breakdown voltage was measured as a voltage when a current greater than a reference value flows through the separator by sandwiching the separator between the upper jig and the lower jig, and applying a voltage between the two jigs.
[6]
However, in the above-described method, only the insulating properties of the separator itself can be measured, and the insulating properties reflecting the charging/discharging characteristics of the electrode assembly in real time cannot be measured. The electrode assembly including the separator is accommodated in the battery case while impregnated in the electrolyte. In addition, dendrites generated in the charging/discharging process of the secondary battery cause a change in volume, which is a cause of applying pressure to the separator. Therefore, there is a need for a technology capable of confirming the resistance characteristics of the separator reflecting the actual use conditions of the secondary battery.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[7]
The present invention has been devised to solve the above problems, and an object of the present invention is to provide an apparatus and method for evaluating the resistance of a separator reflecting the actual operating state of a secondary battery.
means of solving the problem
[8]
The pressurized separator resistance measuring apparatus according to the present invention has a structure in which the upper part is open and the lower part and the side surfaces are closed, and includes: a receiving part for accommodating the separator immersed in the electrolyte; a mold part inserted through the open upper part of the accommodating part to press the received separation membrane; a pressure control unit for controlling the pressure applied to the separation membrane by adjusting the height of at least one of the receiving unit and the mold unit; A first electrode electrically connected to the inner bottom surface of the accommodating part, protruding to the outside of the accommodating part and electrically connected to the resistance measuring part, and electrically connected to the lower surface of the mold part, and protruding to the outside of the mold part an electrode unit including a second electrode electrically connectable to the resistance measuring unit; and a resistance measuring unit respectively connected to the first and second electrodes of the electrode unit to measure the resistance of the separator.
[9]
In one example, the pressure-type separation membrane resistance measuring device is formed on the outside of the lower part of the mold to be inserted into the receiving part, and a gasket for maintaining the airtightness of the inner space partitioned by the inner side of the receiving part and the lower surface of the mold part. include
[10]
In another example, the pressure-type separation membrane resistance measuring device, but located below the accommodating part, further comprising a pressure measuring part for measuring the pressure transferred to the accommodating part by the pressurization of the mold part.
[11]
In one example, the pressure-type separator resistance measuring apparatus according to the present invention, a pressure display unit indicating a pressure value controlled by the pressure control unit; and any one or more of a resistance display unit indicating a resistance value measured by the resistance measuring unit.
[12]
In a specific example, in the pressurized membrane resistance measuring device, the pressure adjusting portion P 0 from P 1 continuously or after sequentially increased pressure, again P to 1 from P 0 to lower the pressure in a row or sequentially to be (where, P 0 represents the pressure in a state in which the separator is not pressurized, and P 1 represents a preset reference pressure), and the resistance measuring unit measures the resistance of the separator in real time according to the pressure change by the pressure adjusting unit.
[13]
The present invention also provides a method for measuring the resistance of a pressurized separator. In one example, in the method for measuring the resistance of the pressurized separator, the separation membrane immersed in the electrolyte is accommodated in the receiving unit having an open upper portion and a closed lower and side surfaces, and is inserted through the open upper portion of the receiving unit. changing the pressure applied to the separation membrane accommodated by the mold unit, and measuring the resistance of the separation membrane while the pressure is changed.
[14]
In a specific example, in the method for measuring the resistance of the pressurized separator, the pressure applied to the received separator is, after continuously or sequentially increasing the pressure from P 0 to P 1, and then continuously or sequentially increasing the pressure from P 1 to P 0 again . will lower Here, P 0 represents a pressure in a state in which the separation membrane is not pressurized, and P 1 represents a preset reference pressure.
[15]
In one embodiment, the pressurized membrane resistance measurement method, in the process of increasing the pressure P 0 the initial resistance (R, measured S ); resistance measured at pressure P 1 (R H ); and determining that the separator is defective when at least one of the last resistances ( RF ) measured at P 0 in the process of lowering the pressure is out of a predetermined reference range.
[16]
In yet another example, the pressurized membrane resistance measurement method, in the process of increasing the pressure P 0 the initial resistance (R, measured S in the process of lowering) the pressure P 0 measured at the last resistance (R F difference) and determining that the separator is defective when (R D ) is out of a predetermined reference range.
[17]
In one example, in the method for measuring the resistance of the pressurized separator, the pressure applied to the received separator is continuously or sequentially changed, and the resistance of the separator according to the change in pressure is measured in real time.
Effects of the Invention
[18]
The pressurized separator resistance measuring apparatus and measuring method according to the present invention measure the resistance according to the pressure change for the separator impregnated in the electrolyte in real time, and through this, the resistance characteristic analysis of the separator reflecting the actual operating state of the secondary battery It is possible.
Brief description of the drawing
[19]
1 is a schematic diagram showing a cross-sectional structure of a pressure-type separator measuring apparatus according to an embodiment of the present invention.
[20]
2 is a graph showing the resistance measurement results according to pressure with respect to the separator specimen according to Example 1 of the present invention.
[21]
3 is a graph showing the resistance measurement results according to pressure with respect to the separator specimen according to Example 2 of the present invention.
[22]
4 is a graph showing the resistance measurement results according to pressure with respect to the separator specimen according to Example 3 of the present invention.
[23]
5 is a graph showing the resistance measurement results according to pressure with respect to the separator specimen according to Example 4 of the present invention.
Modes for carrying out the invention
[24]
Hereinafter, the present invention will be described in detail. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. It should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention based on the principle that it can be defined as
[25]
[26]
The present invention provides an apparatus for measuring the resistance of a pressurized separator. Specifically, the evaluation device is
[27]
a storage unit having an open upper portion and a closed lower portion and side surfaces, and accommodating a separator immersed in an electrolyte;
[28]
a mold part inserted through the open upper part of the accommodating part to press the received separation membrane;
[29]
a pressure control unit for controlling the pressure applied to the separation membrane by adjusting the height of at least one of the receiving unit and the mold unit;
[30]
A first electrode electrically connected to the inner bottom surface of the accommodating part, protruding to the outside of the accommodating part and electrically connected to the resistance measuring part, and electrically connected to the lower surface of the mold part, and protruding to the outside of the mold part an electrode unit including a second electrode electrically connectable to the resistance measuring unit; and
[31]
and a resistance measuring unit respectively connected to the first and second electrodes of the electrode unit to measure the resistance of the separator.
[32]
The accommodating part has a structure in which the upper part is open and the lower part and the side surface are closed. Through this, the separation membrane immersed in the electrolyte is accommodated in the accommodating part. The mold part is inserted through the open upper part of the accommodating part to press the received separation membrane.
[33]
In general, an electrode assembly including a separator is accommodated in a battery case in a state impregnated with an electrolyte. In addition, dendrites generated in the charging/discharging process of the secondary battery cause a change in volume, which is a cause of applying pressure to the separator. In the present invention, pressure is applied to the separator immersed in the electrolyte, which reflects the actual use conditions of the secondary battery.
[34]
A first electrode electrically connected to the inner bottom surface of the accommodating part and a second electrode electrically connected to a lower surface of the mold part are respectively formed to protrude to the outside of the device. A resistance measuring unit is connected to the first and second electrodes. Therefore, the measuring device according to the present invention can measure the resistance of the separator according to the pressure applied at the same time as applying the pressure to the separator in real time.
[35]
In addition, the resistance measuring unit is not particularly limited as long as it measures the resistance of the electrolyte-impregnated separator. For example, the resistance measuring unit calculates resistance through AC impedance measurement.
[36]
In one embodiment, the measuring device is formed on the outside of the lower part of the mold to be inserted into the receiving part, the gasket (gasket) for maintaining the airtightness of the inner space partitioned by the inner side of the receiving part and the lower surface of the mold part include more The gasket is formed outside the lower portion of the mold portion inserted into the receiving portion. The material of the gasket is not particularly limited as long as it can maintain the airtightness of the inner space partitioned by the inner side of the receiving part and the lower surface of the mold part. For example, the gasket may be in the form of an O-ring that is a ring-shaped rubber material. One to five O-rings may be formed in parallel on the lower outer side of the mold part.
[37]
In one embodiment, the measuring device, but located below the receiving unit, further comprising a pressure measuring unit for measuring the pressure transferred to the receiving unit by the pressurization of the mold unit. Since the pressure measuring unit is located below the receiving unit, it is possible to effectively measure the pressure transferred to the receiving unit. For example, the pressure measuring unit is in the form of a miniature compression load cell located below the receiving unit.
[38]
In one embodiment, the measuring device includes: a pressure display unit indicating a pressure value controlled by the pressure adjusting unit; and any one or more of a resistance display unit indicating a resistance value measured by the resistance measuring unit. The pressure display unit displays the pressure value measured by the pressure measuring unit described above. For example, the pressure display unit is a digital display device. In addition, the resistance display unit displays a resistance value measured by the resistance measuring unit. For example, the resistance display unit may calculate a resistance value for each pressure value.
[39]
In yet another embodiment, the pressure adjusting portion P 0 from P 1 Raise pressure continuously or sequentially to, again, P 1 from P 0 is the pressure lowered continuously or sequentially to. In addition, the resistance measuring unit measures the resistance of the separator according to the pressure change by the pressure adjusting unit in real time.
[40]
Here, P 0 represents a pressure in a state in which the separation membrane is not pressurized, and P 1 represents a preset reference pressure. For example, P 0 is a pressure in a state in which the separator is not pressurized, and may be displayed as 0 Mpa, P 1 represents a preset reference pressure, and may be set in a range of 4 to 8 Mpa.
[41]
Specifically, although there is a difference depending on the assembly type or type of the battery, a pressure of about 4 Mpa is applied when charging in a 2.1 Ah stack cell (11 stack) level cell. In this case, the P 1 can be set in the range of 4 to 5 Mpa.
[42]
[43]
The present invention also provides a method for measuring the resistance of a pressurized separator, the measuring method can be performed using the above-described measuring device.
[44]
In one example, in the measuring method, in a state in which a separator immersed in an electrolyte solution is accommodated in a receiving unit having an open upper portion and a closed lower portion and side surfaces, the mold portion inserted through the open upper portion of the receiving portion changing the pressure applied to the separation membrane accommodated by the method, and measuring the resistance of the separation membrane while the pressure is changed.
[45]
In one embodiment, the pressure applied to the received separation membrane is, after continuously or sequentially increasing the pressure from P 0 to P 1 , and then continuously or sequentially from P 1 to P 0 (here, P 0 is the separation membrane Represents a pressure in a non-pressurized state, and P 1 represents a preset reference pressure) is lowered. Descriptions of P 0 and P 1 are the same as above.
[46]
In another embodiment, in the method for measuring the resistance of the pressurized separator according to the present invention, it is also possible to determine whether the separator is defective by measuring the resistance of the separator.
[47]
In a specific example, the measuring method, in the process of increasing the pressure P 0 the initial resistance (R, measured S ); resistance measured at pressure P 1 (R H ); and determining that the separator is defective when at least one of the last resistances ( RF ) measured at P 0 in the process of lowering the pressure is out of a predetermined reference range. This is to set a reference resistance range for each pressure of the separator, and if the measured value is out of this range, it is judged as defective.
[48]
In another specific example, the measurement method is, in the process of increasing the pressure P 0 the initial resistance (R, measured S in the process of lowering) the pressure P 0 of the last resistance (R measured in F difference) (R D ) and determining that the separation membrane is defective when is out of a predetermined reference range. In this case, when pressure is applied to the separator and then the applied pressure is removed, by comparing the initial resistance value and the later resistance value of the separator, it is confirmed whether or not the physical properties of the separator change with respect to the pressure. If the change in the resistance value is out of the reference range, it is determined as defective.
[49]
In one embodiment, in the measuring method, the pressure applied to the received separation membrane is changed continuously or sequentially, and the resistance of the separation membrane according to the change in pressure is measured in real time. The measuring method according to the present invention has the advantage that the resistance change of the separator according to continuous or sequential pressure change can be checked in real time.
[50]
[51]
As the separator to be evaluated in the present invention, any porous substrate used in a secondary battery may be used, for example, a polyolefin-based porous membrane or a nonwoven fabric may be used, but is not particularly limited thereto.
[52]
Examples of the polyolefin-based porous membrane include polyethylene such as high-density polyethylene, linear low-density polyethylene, low-density polyethylene, and ultra-high molecular weight polyethylene, and polyolefin-based polymers such as polypropylene, polybutylene, and polypentene, respectively, individually or in a mixture thereof. One membrane is mentioned.
[53]
In addition, the separator includes a case in which a porous coating layer including inorganic particles is formed on one or both surfaces of the porous substrate. In one embodiment, the separator includes a porous polymer substrate and a porous coating layer formed on one or both surfaces of the porous substrate. The polymer substrate may be a polymer substrate having pores formed during polymerization or a structure in which pores are formed through stretching. In addition, the porous coating layer may have a structure in which inorganic particles are coated on the surface of a polymer substrate. The inorganic particle coating layer serves to increase the conductivity of ions without impairing the porosity of the polymer substrate.
[54]
For example, the porous polymer substrate is formed of a polyolefin resin, and the porous coating layer includes inorganic particles, a lithium salt, and a binder resin, and the inorganic particles are connected and fixed to each other by the binder resin to form a porous structure. Specifically, the porous polymer substrate is a thin film in the form of a sheet and is applicable if it has excellent ion permeability and mechanical strength. As the material of the polymer substrate, for example, a polyolefin-based film such as polypropylene having excellent chemical resistance, a sheet or nonwoven fabric made of glass fiber or polyolefin, etc. are used. Commercially available, e.g. Celgard ™ 2400, 2300 (Hoechest Celanse corp), polypropylene membrane (Ube Industrial Ltd. or Pall RAI) or polyethylene (Tonen or Entek) ) may be used, but the present invention is not limited thereto, and the porous coating layer serves to complement the mechanical strength of the porous reinforcing material and impart heat resistance.
[55]
The inorganic particles are connected and fixed to each other by a binder resin to be described later to form a porous structure. The porous coating layer has a porous structure by an interstitial volume between the inorganic particles, and the interstitial volume is substantially in a closed packed structure or a densely packed structure by the inorganic particles. It is a space limited by the inorganic particle being interviewed.
[56]
The binder resin is not particularly limited as long as it is a component that is not easily dissolved by the electrolyte while exhibiting the bonding strength with the electrode mixture layer laminated on the current collector and the bonding strength between the inorganic components and lithium salts in the mixed coating layer. For example, the binder resin is polyvinylidene fluoride (PVdF), polyvinylidene fluoride-hexafluoropropylene (polyvinylidene fluoride-cohexafluoropropylene), polyvinylidene fluoride-trichloroethylene (polyvinylidene fluoridecotrichlorethylene), polyvinyl Leadenfluoride-chlorotrifluoroethylene (PVdF-CTFE), polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, ethylene Vinyl acetate copolymer (polyethylene-co-vinyl acetate), polyethylene oxide (polyethylene oxide), cellulose acetate (cellulose acetate), cellulose acetate butyrate (cellulose acetate butyrate), cellulose acetate propionate (cellulose acetate propionate), cyano Ethyl pullulan (cyanoethylpullulan), cyanoethylpolyvinylalcohol (cyanoethylpolyvinylalcohol), cyanoethylcellulose (cyanoethylcellulose), cyanoethylsucrose (cyanoethylsucrose), pullulan (pullulan),
[57]
The content of the binder resin may be contained in the range of 0.1 to 20% by weight or 1 to 10% by weight of 100% by weight of the porous coating layer in consideration of the binding force between the inorganic particles and/or lithium salt and the binding force of the current collector and the electrode mixture. have.
[58]
In addition, in the present invention, the resistance is measured with respect to the type of separator impregnated in the electrolyte. The same composition as the electrolyte applied to the secondary battery, which is the electrolyte, may be applied. In one example, the electrolyte may use a non-aqueous electrolyte including a non-aqueous electrolyte. Examples of the non-aqueous electrolyte include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butylo Lactone, 1,2-dimethoxyethane, tetrahydroxy franc, 2-methyl tetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile , nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxy methane, dioxolane derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, Aprotic organic solvents such as tetrahydrofuran derivatives, ethers, methyl pyropionate, and ethyl propionate may be used. However, it is not particularly limited thereto, and a number of electrolyte components typically used in the field of lithium secondary batteries may be added or subtracted within an appropriate range.
[59]
The measuring apparatus and measuring method according to the present invention according to the present invention can be applied to various types of separators for secondary batteries. For example, the separator is a separator for a lithium secondary battery.
[60]
The lithium secondary battery may include, for example, an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode; a non-aqueous electrolyte for impregnating the electrode assembly; and a battery case containing the electrode assembly and the non-aqueous electrolyte.
[61]
The positive electrode has a structure in which a positive electrode active material layer is laminated on one or both surfaces of a positive electrode current collector. The positive active material may be each independently a lithium-containing oxide, and may be the same or different. As the lithium-containing oxide, a lithium-containing transition metal oxide may be used. In one example, the positive electrode active material layer includes a conductive material and a binder polymer in addition to the positive electrode active material, and, if necessary, may further include a positive electrode additive commonly used in the art.
[62]
The current collector used for the positive electrode is a metal with high conductivity, and any metal that can be easily adhered to the positive electrode active material slurry and has no reactivity in the voltage range of the electrochemical device may be used. Specifically, non-limiting examples of the current collector for the positive electrode include a foil made of aluminum, nickel, or a combination thereof.
[63]
The negative electrode may include a carbon material, lithium metal, silicon or tin as an anode active material. When a carbon material is used as the negative electrode active material, both low crystalline carbon and high crystalline carbon may be used. Soft carbon and hard carbon are representative of low crystalline carbon, and natural graphite, Kish graphite, pyrolytic carbon, and liquid crystal pitch-based carbon fiber are representative of high crystalline carbon. (mesophase pitch based carbon fiber), carbon microspheres (mesocarbon microbeads), liquid crystal pitches (Mesophase pitches), and high-temperature calcined carbon such as petroleum and coal-based cokes (petroleum orcoal tar pitch derived cokes) are representative.
[64]
Non-limiting examples of the current collector used for the negative electrode include a foil made of copper, gold, nickel, or a copper alloy, or a combination thereof. In addition, the current collector may be used by stacking substrates made of the above materials.
[65]
In addition, the negative electrode may include a conductive material and a binder commonly used in the art.
[66]
[67]
Hereinafter, the present invention will be described in more detail with reference to drawings and the like.
[68]
1 is a schematic diagram showing a cross-sectional structure of a pressure-type separator measuring apparatus according to an embodiment of the present invention. 1, the measuring device according to the present invention has a structure in which the upper part is open but the lower part and the side surfaces are closed, and an accommodating part 100 for accommodating a separator immersed in an electrolyte solution, and the opening of the accommodating part 100 It includes a mold part 200 that is inserted through the upper part to pressurize the received separator, and a pressure regulator 220 that controls the pressure applied to the separator through height adjustment of the mold part 200 . In addition, on the outside of the measuring device, the first electrode 130 electrically connected to the inner bottom surface of the accommodating part 100 and protruding to the outside of the accommodating part 100 , and the mold part 200 . ) and electrically connected to the lower surface, the second electrodes 230 protruding to the outside of the mold part 200 are respectively positioned. The first electrode 130 and the second electrode 230 are electrically connected to a resistance measuring unit (not shown), respectively.
[69]
An O-ring-shaped gasket 210 is formed on the outside of the mold part 200 . The gasket 210 serves to maintain the airtightness of the inner space partitioned by the inner side of the accommodating part 100 and the lower surface of the mold part 200 .
[70]
In addition, the pressure measuring units 110 and 120 are positioned under the receiving unit 100 . The pressure measuring units 110 and 120 measure the pressure transferred to the receiving unit 100 by the pressurization of the mold unit 200 . In one example, the pressure measuring unit 110, 120 may be applied to a miniature compression load cell.
[71]
[72]
Hereinafter, the present invention will be described in more detail with reference to examples and drawings.
[73]
[74]
Example 1: Preparation of separator
[75]
5 wt% of polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP) polymer was added to acetone and dissolved at 50° C. for about 12 hours or more, and then Al 2 O 3 powder was added to the binder polymer: Al 2 O 3 = 10: 90 weight ratio was added.
[76]
Then, Al 2 O 3 powder was crushed and dispersed using a ball mill for 12 hours or more to prepare a binder polymer slurry. The Al 2 O 3 particle diameter of the binder polymer slurry was about 400 nm.
[77]
Next, an organic and inorganic composite separator was prepared by coating a polyethylene porous membrane (porosity 45%) with a thickness of 3 μm on both sides of an 18 μm thick polyethylene porous membrane (porosity 45%) using a dip coating method. As a result of measuring the organic and inorganic composite separator with a porosimeter, the pore size and porosity in the porous coating layer coated on the polyethylene porous membrane were 0.4 μm and 55%, respectively.
[78]
[79]
Example 2: Preparation of separator
[80]
A separator was prepared in the same manner as in Example 1, except that a slurry containing a ceramic component was coated on both sides of a 7 μm thick polyethylene porous membrane to a thickness of 2.5 μm.
[81]
[82]
Example 3: Separator Membrane Preparation
[83]
Separation membrane in the same manner as in Example 1, except that a commercially available polyethylene porous membrane having a high molecular weight was selected and a slurry containing a ceramic component was coated on both sides of a 9 μm thick porous membrane to a thickness of 1.5 μm. was prepared.
[84]
[85]
Example 4: Separator Membrane Preparation
[86]
A fabric-free separator having a thickness of 15 μm and having excellent compression resistance made of a combination of ceramic and binder was prepared without a polyethylene porous membrane fabric.
[87]
[88]
Experimental Example: Measuring the resistance of the separator according to the pressure
[89]
The separator specimen prepared in Example 1 was sufficiently impregnated in the electrolyte (EC/EMC=1:2 volume ratio, 1 mol LiPF 6 ). The membrane specimen impregnated with the electrolyte was charged into the receiving part of the measuring device shown in FIG. 1 , and the resistance of the separator according to the pressure was measured.
[90]
To measure the resistance of the separator, the resistance was measured while increasing the pressure sequentially from P 0 to P 1 , and the resistance was measured while decreasing the pressure sequentially from P 1 to P 0 again . In this experimental example, the pressure P 0 is 0 Mpa, which is a pressure in a state in which the separator is not pressurized, and the pressure P 1 is set to 4.8 Mpa. The result of measuring the resistance of the separator is shown in FIG. 2 .
[91]
Referring to FIG. 2 , the resistance value of the separator increased from 2.8Ω to 3.15Ω during the pressurization process. During the decompression process, the resistance to the separator decreased from 3.15Ω to 2.95Ω. From the result of FIG. 2 , when the separator impregnated with the electrolyte is pressurized, the resistance is increased due to internal pore breakdown and the like. Then, even if the pressure applied to the separator is reduced or removed, it can be seen that the resistance of the separator is not reduced back to the initial resistance level.
[92]
In addition, referring to the result of FIG. 2 , the initial resistance of the separator is 2.8Ω, and the final resistance through the process of applying pressure is 2.95Ω. In the case of the separator of this embodiment, the difference between the initial resistance and the final resistance is calculated to be 0.15Ω. When the defect determination criterion of the separator is set to 0.2Ω based on the difference between the initial resistance and the final resistance of the separator, the separator according to the present embodiment is determined to be good quality.
[93]
[94]
In addition to Example 1, the resistance of the separator according to pressure was measured in the same manner in Examples 2 to 4, and the results are shown in FIGS. 3 to 5, respectively.
[95]
As a result of the measurement, in the case of Example 2 shown in FIG. 3, the initial resistance was 2.24 Ω and the final resistance was 3.23 Ω, and the increase in resistance compared to the initial resistance was very severe, and the increased resistance was not recovered even when the pressure was sequentially lowered. appears not to Therefore, when the failure determination criterion of the separator is set to 0.2Ω based on the difference between the initial resistance and the final resistance of the separator, it is determined as defective.
[96]
In the case of Example 3 shown in FIG. 4, it is a separator using a high molecular weight compression-resistant polyethylene fabric, and it can be seen that the resistance property is excellent because there is almost no increase in resistance even when the pressure is increased from the initial resistance of 0.48 Ω. Therefore, in the case of the separation membrane of Example 3, it is preferable to set the defect determination reference value to be lower.
[97]
In the case of Example 4 shown in FIG. 5, it is a fabric-free separator made of a combination of ceramic and binder, and has very excellent compression resistance. Accordingly, even if the pressure is increased from the initial resistance of 1.61Ω, there is little increase in the resistance, and the change is not large even if the pressure is decreased. Therefore, similarly to the separation membrane of Example 3, it is preferable to set the defect determination reference value lower.
[98]
[99]
Above, the present invention has been described in more detail with reference to the drawings and examples. However, the configurations described in the drawings and embodiments described in this specification are only one embodiment of the present invention and do not represent all of the technical spirit of the present invention, so at the time of the present application, various equivalents and It should be understood that there may be variations.
[100]

[101]
100: storage unit
[102]
110, 120: pressure measuring unit
[103]
130: first electrode
[104]
200: mold part
[105]
210: gasket
[106]
220: pressure control unit
[107]
230: second electrode
Claims
[Claim 1]
a storage unit having an open upper portion and a closed lower portion and side surfaces, and accommodating a separator immersed in an electrolyte; a mold part inserted through the open upper part of the accommodating part to press the received separation membrane; a pressure control unit for controlling the pressure applied to the separation membrane by adjusting the height of at least one of the receiving unit and the mold unit; A first electrode electrically connected to the inner bottom surface of the accommodating part, protruding to the outside of the accommodating part and electrically connected to the resistance measuring part, and electrically connected to the lower surface of the mold part, and protruding to the outside of the mold part an electrode unit including a second electrode electrically connectable to the resistance measuring unit; and a resistance measuring unit respectively connected to the first and second electrodes of the electrode unit to measure the resistance of the separator.
[Claim 2]
The pressure measuring device of claim 1, further comprising a gasket formed outside the lower portion of the mold unit to be inserted into the receiving unit, and further comprising a gasket for maintaining airtightness of an inner space defined by the inner side of the receiving unit and the lower surface of the mold unit. .
[Claim 3]
The pressure measuring device of claim 1 , further comprising a pressure measuring unit positioned below the receiving unit and measuring the pressure transferred to the receiving unit by pressurizing the mold unit.
[Claim 4]
The pressure display unit according to claim 1, further comprising: a pressure display unit indicating a pressure value controlled by the pressure adjusting unit; And Pressurized separator resistance measuring device further comprising any one or more of the resistance display unit indicating the resistance value measured by the resistance measuring unit.
[Claim 5]
The method of claim 1, wherein the pressure adjusting portion P 0 from P 1, and then increased the pressure continuously or sequentially, again P to 1 from P 0 to lower the pressure in a row or sequentially to be (where, P 0 is not pressurized the membrane represents the pressure of the state, and P 1 represents a preset reference pressure), and the resistance measuring unit measures the resistance of the separator according to the pressure change by the pressure adjusting unit in real time.
[Claim 6]
In a state in which the separator immersed in the electrolyte is accommodated in the accommodating part having the upper part open but the lower part and the side closed structure, the pressure applied to the separator housed by the mold part inserted through the open upper part of the accommodating part is changed. A method of measuring the resistance of a pressurized separator comprising the step of measuring the resistance of the separator while the pressure is changed.
[Claim 7]
The method of claim 6, wherein the pressure applied to the received separation membrane is, after continuously or sequentially increasing the pressure from P 0 to P 1, and then continuously or sequentially from P 1 to P 0 (here, P 0 is the separation membrane Represents a pressure in a non-pressurized state, and P 1 represents a preset reference pressure).
[Claim 8]
The method of claim 7, wherein, in the process of increasing the pressure P 0 the initial resistance measured in (R S ); resistance measured at pressure P 1 (R H ); and determining that the separator is defective when any one or more of the final resistance (R F ) measured at P 0 in the process of lowering the pressure is out of a predetermined reference range.
[Claim 9]
The method of claim 7, wherein in the process to increase the pressure P 0 the initial resistance (R, measured S in the process of lowering) the pressure P 0 measured at the last resistance (R F difference) (R D ) is a predetermined reference range If it is out of the pressure-type separator resistance measurement method comprising the step of determining that the separator is defective.
[Claim 10]
The method of claim 6, wherein the pressure applied to the received separator is continuously or sequentially changed, and the resistance of the separator according to the change in pressure is measured in real time.