Composite diaphragm for electrochemical device, flame-retardant diaphragm, electrochemical device, and electrochemical module and device containing the same

Abstract

The present invention relates to a composite diaphragm for an electrochemical device, a flame-retardant diaphragm, an electrochemical device, and an electrochemical module and device comprising the same. The composite diaphragm according to the present invention comprises a porous substrate and a crystalline metal salt. The composite diaphragm can be used as a salt supply source for a liquid electrolyte of an electrochemical device, and simultaneously or independently thereof, can have flame retardancy due to the metal salt.

Description

Technical Field

[0001] The present invention relates to a composite diaphragm for electrochemical devices, a flame-retardant diaphragm, an electrochemical device, and an electrochemical module and device containing the same. In detail, it relates to a diaphragm for an electrochemical device that can have improved flame retardancy and / or improved ionic conductivity, and at the same time or independently, can realize an electrochemical device with a high concentration of electrolyte. Background Art

[0002] With the trend toward higher performance, lighter weight, and larger electrochemical devices (e.g., for automotive power supplies), research into high energy density and high capacity is actively underway. While research is underway to achieve higher capacity and higher output in each component of an electrochemical device (e.g., developing electrode materials that achieve higher energy density, thinner separators with improved wettability, and electrolytes with improved conductivity), commercialization of large and medium-sized electrochemical devices for applications such as electric vehicles requires ensuring safety (eliminating the risk of explosion).

[0003] The diaphragm prevents short circuits by preventing physical contact between the two electrodes in the electrochemical device, while providing a channel for ions to move back and forth. When the temperature of the electrochemical device is too high, in order to block the current, part of the diaphragm melts to provide a sealing function to block the pores.

[0004] In order to achieve high capacity and high output of electrochemical devices, a diaphragm is required that has a low sealing temperature, a high short-circuit temperature, a low thermal shrinkage rate, excellent cycle performance based on high ionic conductivity, and excellent electrolyte wettability. To ensure the safety of electrochemical devices, it is most important to develop a diaphragm with excellent flame retardancy. Summary of the Invention

[0005] Problems to be solved by the invention

[0006] An object of the present invention is to provide a separator having excellent flame retardancy.

[0007] Another object of the present invention is to provide a separator having improved thermal stability.

[0008] Another object of the present invention is to provide a separator with improved ionic conductivity.

[0009] Another object of the present invention is to provide a separator having excellent wettability with a liquid electrolyte.

[0010] Another object of the present invention is to provide a separator capable of realizing an electrochemical cell having a high concentration of liquid electrolyte.

[0011] Another object of the present invention is to provide an electrochemical cell having improved flame retardancy, thermal stability, ionic conductivity, electrolyte wettability, and productivity, and a method for manufacturing the same.

[0012] Another object of the present invention is to provide a coating liquid for electrochemical cell production having improved at least one of flame retardancy, thermal stability, ion conductivity, electrolyte wettability, and productivity.

[0013] Means used to solve problems

[0014] The composite separator according to the present invention is used for an electrochemical device and includes a porous substrate and a crystalline metal salt.

[0015] According to one embodiment of the composite membrane, the metal salt may include a sulfonyl group-containing metal salt.

[0016] According to one embodiment of the composite separator, the porous substrate may include a porous membrane, and the metal salt may be located on the surface of the porous membrane.

[0017] According to a specific example of a composite diaphragm, the porous substrate may include a porous membrane and a porous coating layer located on at least one side of the porous membrane, and the metal salt may be located in one or more regions including the interface between the porous membrane and the porous coating layer, the interior of the porous coating layer, and the surface of the porous coating layer.

[0018] According to one embodiment of the composite separator, the porous coating layer may include inorganic particles, organic particles, organic-inorganic composite particles, or mixed particles thereof.

[0019] According to a specific example of the composite separator, the sulfonyl group-containing metal salt may be one or more compounds selected from the group consisting of compounds satisfying the following Chemical Formulas 1 to 4.

[0020] [Chemical Formula 1]

[0021]

[0022] In Chemical Formula 1, A + Is a monovalent cation, R1 is F, CFH2, CF2H or C n F 2n+1 (n is a natural number greater than or equal to 1).

[0023] [Chemical Formula 2]

[0024]

[0025] In Chemical Formula 2, A 2+ is a divalent cation, R1 is F, CFH2, CF2H or C n F 2n+1(n is a natural number greater than or equal to 1).

[0026] [Chemical Formula 3]

[0027]

[0028] In Chemical Formula 3, A + is a monovalent cation, R1 and R2 are each independently F, CFH2, CF2H or C n F 2n+1 (n is a natural number greater than or equal to 1).

[0029] [Chemical Formula 4]

[0030]

[0031] In Chemical Formula 4, A 2+ is a divalent cation, R1 and R2 are each independently F, CFH2, CF2H or C n F 2n+1 (n is a natural number greater than or equal to 1).

[0032] According to a specific example of the composite separator, the composite separator can be a salt supply source for providing a metal salt to an electrolyte of an electrochemical device.

[0033] According to one embodiment of the composite separator, the metal salt may be fixed by one or more binding components selected from linear polymers and cross-linked polymers.

[0034] According to one embodiment of the composite separator, the fixing may be achieved by solidifying the solidifying component in a state of being mixed with the metal salt, wherein the solidifying component is converted into an adhesive component through solidification and has curability.

[0035] According to one embodiment of the composite membrane, the composite membrane may include a coating layer located on one side of the porous substrate and comprising a metal salt.

[0036] According to a specific example of a composite diaphragm, the porous substrate may include a porous membrane and a porous coating layer located on at least one side surface of the porous membrane, and the composite diaphragm may include a coating layer located between the porous membrane and the porous coating layer, on the surface area of ​​the porous coating layer, or between the porous membrane and the porous coating layer and in each of the surface areas of the porous coating layer and containing a metal salt.

[0037] According to one embodiment of the composite separator, the coating layer containing the metal salt may further contain one or more polymers selected from linear polymers and cross-linked polymers.

[0038] According to a specific example of the composite membrane, the metal salt content per unit area of ​​the porous substrate may be 0.1 to 5.0 mg / cm 2 .

[0039] According to a specific example of the composite separator, metal ions that participate in the electrochemical reaction of the electrochemical device provided with the composite separator are used as active ions, and the metal ions of the metal salt may include the active ions.

[0040] According to one specific example, the composite separator may satisfy the following formula 1.

[0041] [Formula 1]

[0042] 5(%)≤(W 干 -W 湿 ) / W m ×100(%)

[0043] In formula 1, W 干 is the mass of the composite membrane before contact with the electrolyte, W 湿 W is the mass of the composite membrane recovered and dried after immersing the composite membrane in a reference electrolyte at a temperature of 25°C for 1 hour, wherein the reference electrolyte is an electrolyte in which LiPF6 is dissolved at a concentration of 1 M in a mixed solvent of ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1, m It is the mass of metal salt contained in the composite diaphragm before it comes into contact with the electrolyte.

[0044] The present invention includes a flame retardant separator.

[0045] According to the flame-retardant membrane of the present invention, after being immersed in the following reference electrolyte for 1 minute, it is recovered and placed in a manner such that the in-plane direction of the membrane is parallel to the direction of gravity. When the following flame retardancy test is performed at a time point when no droplets fall from the membrane to the bottom within 1 minute, no flame occurs in the membrane.

[0046] Reference electrolyte: a mixed solvent of ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1, a lithium salt of LiPF6, a LiPF6 concentration of 1 M, and a temperature of 25°C ± 5°C.

[0047] Flame retardancy test: The length of the flame in the atmosphere is 5 to 10 cm, the temperature of the flame tip is 1000 to 1500°C, the length of the flame area not in contact with the diaphragm when the flame is applied to the diaphragm is 50 to 80% of the length of the flame in the atmosphere, and the movement speed of the flame in contact with the diaphragm is 1 to 5 cm / sec.

[0048] The present invention includes an electrochemical device, wherein the electrochemical device includes the composite separator for an electrochemical device.

[0049] The present invention includes an electrochemical device, wherein the electrochemical device includes the flame-retardant separator.

[0050] According to a specific example of an electrochemical device, metal ions participating in the electrochemical reaction of the electrochemical device are used as active ions, and the molar concentration of the salt of the active ions contained in the electrolyte can be 0.5 to 6.0M.

[0051] According to the electrochemical device of the present invention, it includes a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode, and an electrolyte. The metal ions participating in the electrochemical reaction are used as active ions. The electrolyte is a high-concentration electrolyte containing a salt of active ions of more than 1M. When wetted by the electrolyte, the ionic conductivity of the separator is greater than 0.3mS / cm, and the ion migration coefficient of the active ions of the separator is greater than 0.3.

[0052] The present invention includes an electrochemical module (secondary battery module) in which two or more of the above electrochemical devices are electrically connected.

[0053] The present invention includes a device powered by an energy storage device including the electrochemical device described above.

[0054] Effects of the Invention

[0055] An advantage of the composite separator according to one embodiment of the present invention is that, since it contains a crystalline metal salt, it can convert a low-concentration electrolyte into a high-concentration electrolyte within an electrochemical device.

[0056] The composite separator according to one embodiment of the present invention has the advantages of being flame retardant due to its crystallinity and containing the sulfonyl group-containing metal salt, and thus having improved ionic conductivity.

[0057] The composite separator according to the present invention has the advantage that, for electrochemical devices based on electrolytes, previously established processes and materials can be directly employed without substantially altering established structural components and manufacturing processes. Furthermore, it can embody electrochemical devices that can be provided with high-concentration liquid electrolytes without impairing wettability or productivity, as well as electrochemical devices with improved safety due to flame retardancy and / or electrochemical devices with superior electrochemical properties due to improved ionic conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 This is a photograph for evaluating the flame retardancy of Example 3.

[0059] Figure 2 This is a photograph for evaluating the flame retardancy of Example 4.

[0060] Figure 3This is a photograph for evaluating the flame retardancy of Example 5.

[0061] Figure 4 This is a photograph for evaluating the flame retardancy of Example 6.

[0062] Figure 5 This is a photograph for evaluating the flame retardancy of Example 7.

[0063] Figure 6 This is a photograph for evaluating the flame retardancy of Example 8.

[0064] Figure 7 This is a photograph for evaluating the flame retardancy of Example 9.

[0065] Figure 8 This is a photograph for evaluating the flame retardancy of Comparative Example 1.

[0066] Figure 9 The results of X-ray diffraction analysis of Comparative Example 1, Comparative Example 3 and Example 7 were evaluated.

[0067] Figure 10 These are the results of evaluating the adhesive properties of Comparative Example 3 and Example 7.

[0068] Figure 11 The results are for evaluating the volatility characteristics of Comparative Example 3 and Example 7. DETAILED DESCRIPTION

[0069] Below, the diaphragm, electrochemical device and its manufacturing method according to the present invention are described in detail with reference to the attached drawings. In order to fully convey the purport of the present invention to those skilled in the art, the drawings introduced below are provided as examples. Therefore, the present invention is not limited to the drawings presented below, but may also be embodied in other forms, and the drawings presented below may be expressed in an exaggerated form to clearly illustrate the purport of the present invention. At this time, unless the technical terms and scientific terms used are otherwise defined, they have the meanings generally understood by those of ordinary skill in the art to which the present invention belongs, and in the following description and the attached drawings, descriptions of well-known functions and structures that may unnecessarily confuse the purport of the present invention will be omitted.

[0070] Furthermore, as used in the specification and the appended claims, singular forms may also include plural forms unless the context indicates otherwise.

[0071] In this specification and the appended claims, the terms "first", "second" and the like are used to distinguish one structural element from another structural element and are not used for limitation.

[0072] In this specification and the appended claims, terms such as "including" or "having" refer to the presence of features or structural elements recorded in the specification, and do not preclude the possibility of adding one or more other features or structural elements unless otherwise specifically limited.

[0073] In this specification and the appended claims, when a film (layer), region, structural element, etc. is on or above another part, it includes not only being directly on the other part in contact with it, but also including the situation where other films (layers), regions, structural elements, etc. are interposed therebetween.

[0074] Since the electrode assembly of the positive electrode / diaphragm / negative electrode structure that constitutes the electrochemical device is usually surrounded by an isolation membrane on the outside, and there are multiple layers of isolation membranes on the sides of some full cells or double cells, the wettability decreases during electrolyte immersion and the device manufacturing process takes a long time.

[0075] In large and medium-sized electrochemical devices that require safety, power / energy density, and long life, high-concentration electrolytes are required. High-concentration electrolytes have the following advantages: (1) Improved safety: If the electrolyte salt is highly concentrated, the free solvent molecules that do not participate in solvation are extremely reduced. As a result, the volatility is suppressed, resulting in flame retardancy and the effect of suppressing the side reactions of solvent molecules during the charge and discharge process; (2) Improved electrochemical properties: In high-concentration electrolytes where there are almost no free solvent molecules, the migration mechanism of active ions is changed from the existing carrier-transport conduction type to migration through hopping between metal salt-solvent complexes, thereby increasing the conductivity of active metal salt ions. Furthermore, it is known that the solid electrolyte interface (SEI) components of high-concentration electrolytes are mainly anion-derived components, compared to the solid electrolyte interface (SEI) components in which solvent reduction reactions dominate in low-concentration electrolytes with a large number of free solvent molecules. The anion-derived solid electrolyte interface (SEI) improves output characteristics by reducing the resistance of the electron transfer reaction (Electron Transfer Reaction) of active metal salts at the electrode / electrolyte interface; (3) Improvement of life characteristics: While improving the output density mentioned above, high-concentration electrolytes with almost no free solvent molecules improve battery life characteristics by suppressing the dissolution problem of transition metal ions that can cause battery life and stability problems.

[0076] However, as the electrolyte becomes more concentrated, its ionic strength increases, leading to higher viscosity. While commonly used low-concentration electrolytes typically have a viscosity of around 3 mPa, the viscosity of 5.5M LiFSI / DMC (lithium bis(fluorosulfonyl)imide / dimethyl carbonate), a representative high-concentration electrolyte, is approximately 240 mPa. This significantly increases the wettability issues mentioned above, leading to poor battery quality consistency and productivity.

[0077] As a result of the applicant's continuous research on electrochemical devices with high-concentration liquid electrolytes, a technology has been developed that can realize the following electrochemical devices, which does not require substantial changes to the structural components and manufacturing processes that have been firmly established for small electrochemical devices (i.e., electrochemical devices based on low-concentration electrolytes). It can basically directly adopt previously established processes and materials, will not cause deterioration of wettability or decrease in productivity, and can have a high-concentration liquid electrolyte.

[0078] Furthermore, during further research on these technologies, we confirmed that certain substances can impart high flame retardancy to electrochemical devices, and confirmed that electrochemical characteristics can be improved while maintaining flame retardancy, which led to the completion of the present invention.

[0079] The composite membrane according to the present invention is a composite membrane for electrochemical devices, comprising a porous substrate and a crystalline metal salt.

[0080] In the present invention, the composite membrane containing a crystalline metal salt means that at least one diffraction peak of the metal salt may be present in the X-ray diffraction pattern of the composite membrane, and it may refer to the presence of a diffraction peak of a crystal plane in the crystalline structure of a known metal salt. The X-ray diffraction pattern of the composite membrane may be an X-ray diffraction pattern using Cu Kα rays. In this case, the X-ray diffraction pattern of the metal salt used as a benchmark for the presence or absence of the crystalline metal salt may be based on an established library (JCPDS, ICSD, CSD), and may be based on the X-ray diffraction pattern of a powdered crystalline metal salt in the established library.

[0081] The composite separator according to one embodiment of the present invention includes both a porous substrate and a metal salt, thereby providing the metal salt to the liquid electrolyte when in contact with the liquid electrolyte, and the liquid electrolyte in contact with the composite separator may have an increased salt concentration.

[0082] As described above, when a composite separator according to one embodiment is used in an electrochemical cell based on a liquid electrolyte, a metal salt can be supplied to the liquid electrolyte. In this case, the composite separator can convert the liquid electrolyte in the electrochemical cell into a high-concentration electrolyte.

[0083] In this regard, a composite separator according to one embodiment of the present invention may include: a porous substrate; and a crystalline metal salt (in soluble form) that dissolves in a liquid medium containing a solvent for the metal salt when in contact with the liquid medium. The solvent for the metal salt may be interpreted as a liquid substance having a solubility for the metal salt of 0.1 g or greater per 100 g of the liquid substance at room temperature (10 to 30° C.) and atmospheric pressure, specifically 0.5 g or greater per 100 g of the liquid substance, and more specifically 1.0 g or greater per 100 g of the liquid substance.

[0084] Also, in the experiment, when the metal salt is in contact with the liquid medium, it means that the metal salt is dissolved in the liquid medium or the metal salt contained in the composite separator is in a soluble form, which means that the composite separator satisfies the following formula 1.

[0085] [Formula 1]

[0086] 5(%)≤(W 干 -W 湿 ) / W m ×100(%)

[0087] In formula 1, W 干 is the mass of the composite membrane before contact with the electrolyte, W 湿 W is the mass of the composite membrane recovered and dried after immersing the composite membrane in a reference electrolyte at a temperature of 25°C for 1 hour, wherein the reference electrolyte is an electrolyte in which LiPF6 is dissolved at a concentration of 1 M in a mixed solvent of ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1, m It is the mass of the metal salt contained in the composite diaphragm before it comes into contact with the electrolyte. At this time, as far as the drying of the recovered composite diaphragm is concerned, it is fine as long as the solvent of the reference electrolyte is completely volatilized. As an example, it can be dried by vacuum drying, heating drying at a temperature of 60 to 120°C for 1 to 24 hours, hot air drying, etc., but it is not limited to this. Moreover, as for the volume of the reference electrolyte in which the composite diaphragm is completely flooded, it is fine as long as the mass of the composite diaphragm after contact with the electrolyte is not affected by the volume of the reference electrolyte. As an example, based on the apparent volume of the composite diaphragm, the volume of the reference electrolyte can be 50 to 1000 times, but it is not necessarily limited to this.

[0088] Formula 1 represents the dissolution rate (%) of the metal salt contained in the composite membrane when the composite membrane is immersed in the reference electrolyte for 1 hour. According to a specific example of the composite membrane, (W干 -W 湿 ) / W m The dissolution rate defined by ×100(%) may be 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% or more, 90% or more, 95% or more, or substantially 100%. A dissolution rate of 100% means that all the metal salts contained in the composite separator before contact with the electrolyte are dissolved in the reference electrolyte.

[0089] Because the composite separator contains a crystalline metal salt, it can exhibit a solubility rate as defined in Formula 1, regardless of the presence or absence of a binder (binding component) described below. However, when the crystalline metal salt is bound (including adsorbed) to a porous substrate alone without a binder (binding component), it can exhibit a solubility rate of 30% or greater, 40% or greater, 50% or greater, 60% or greater, 70% or greater, 80% or greater, 90% or greater, or substantially 100%. Composite separators with such high solubility rates can be fabricated using established, well-known procedures involving inserting an electrode assembly comprising a positive electrode, a separator, and a negative electrode into an electrochemical device housing and injecting a liquid electrolyte (a liquid electrolyte that is easily injected due to its lower salt concentration than required), without the problems associated with conventional high-concentration electrolytes.

[0090] For the composite membrane that acts as a salt supply source, a metal salt containing active ions is preferably used as a crystalline metal salt. The salt supply source function refers to the conversion of the low-concentration electrolyte into a high-concentration electrolyte within the electrochemical device after the low-concentration electrolyte is injected. In other words, the metal ions participating in the electrochemical reaction of the electrochemical device provided with the composite membrane are used as active ions. Preferably, the metal ions of the crystalline metal salt include active ions. In fact, preferably, the crystalline metal salt is a crystalline salt of active ions. In this case, the solute (electrolyte salt) contained in the low-concentration electrolyte and the crystalline metal salt contained in the composite membrane can be of the same or different species.

[0091] After the composite membrane is brought into contact with a liquid electrolyte or a liquid medium containing a solvent injected during the electrochemical device manufacturing process to provide a metal salt as a solute (electrolyte salt), the concentration of the metal salt in the porous substrate (including adjacent meanings) can be maintained at a relatively high state for a long time compared to the positive and negative electrodes. Due to the concentration gradient formed by the metal salt derived from the membrane (composite membrane), the electrolyte components in the membrane, positive electrode, and negative electrode have different surface tensions. In an electrochemical device in which there is no external force such as a separate convection force, the concentration of the metal salt derived from the membrane can be maintained at a relatively high state for a long time compared to the positive and negative electrodes. Due to this concentration gradient, the thermal stability or flame retardancy of the membrane and / or the ionic conductivity of the active metal ions can be improved.

[0092] That is, for an electrochemical device manufactured by placing an electrode assembly including a positive electrode, a composite diaphragm, and a negative electrode into a case and injecting and sealing a liquid electrolyte, even if the dissolution rate of the installed composite diaphragm reaches 100%, the concentration of the solute (electrolyte salt) in the electrolyte region in contact with the composite diaphragm side and the electrolyte region in contact with the electrode may be different. In the entire electrolyte region, the concentration (CH) of the electrolyte region in contact with the composite diaphragm side may be relatively high, and the concentration (CL) of the electrolyte region in contact with the electrode may be relatively low. That is, CH and CL may satisfy the relationship of CH>CL, and in fact, CH>1.5CL may be satisfied. A liquid electrolyte with a non-uniform concentration may have a concentration gradient in which the concentration of the solute (electrolyte salt) decreases from the composite diaphragm toward the electrode. At this time, the concentration gradient may actually decrease continuously from the composite diaphragm toward the electrode.

[0093] According to a specific example of a composite membrane, considering the commercial composite membrane manufacturing process and considering the smooth contact and / or large contact area between the liquid electrolyte and the metal salt contained in the composite membrane, in the composite membrane, the crystalline metal salt can be located in the surface area of ​​the porous substrate.

[0094] The crystalline metal salt located on the surface of the porous substrate may include a metal salt in an adsorbed and / or fixed state. In this case, adsorption may include physical adsorption and / or chemical adsorption. Furthermore, fixation may include fixation of the metal salt itself by bonding to the porous substrate and / or fixation by a foreign substance different from the metal salt, i.e., fixation by an external factor including a foreign substance. In this case, the foreign substance used to fix the metal salt may be deformed (for example, swollen) or dissolved by the liquid medium or solvent, and the metal salt may become soluble in the liquid medium or solvent.

[0095] The surface area of ​​the porous substrate may be defined as the total thickness of the porous substrate (the shortest distance between the two widest surfaces facing each other) being considered as t pm When the thickness direction of the porous substrate is 0.05 to 0.3t from one surface toward pm The surface area of ​​the porous substrate can be more substantially defined by considering the specific structure of the porous substrate.

[0096] The porous substrate may include a porous film, and the porous film may be an insulator and may have microporosity. The porous film prevents physical contact between the electrodes while playing a role in allowing metal ions such as lithium ions to pass through the pores. As long as it is an organic or inorganic porous film commonly used as a separator in a secondary battery, it can be used without any particular restrictions. As a specific example, the porous film is a porous polymer film, for example, it can be a porous polymer film, a woven fabric, a non-woven fabric or a laminated structure of more than two layers thereof selected from the group consisting of polyolefin resins, fluorine resins, polyester resins, polyacrylonitrile resins and cellulose resins, but is not limited thereto. The thickness of the porous film, as long as it is the usual range for the field of secondary batteries, can be, for example, 1 to 1000 μm, specifically 10 to 800 μm, but is not limited thereto.

[0097] In one embodiment, the crystalline metal salt may be located on the surface of the porous membrane. In this case, the surface of the porous membrane includes not only the outermost surface of the porous membrane but also the surface based on the open pores (pore surface of the open pores).

[0098] The porous substrate may include: a porous membrane; and a porous coating layer located on at least one surface or both surfaces of the porous membrane.

[0099] The porous coating layer may include inorganic particles, organic particles, organic-inorganic composite particles, or a mixture thereof, and may have porosity through the gaps between the particles. There is no particular limitation on the particle phase (inorganic particles, organic particles, organic-inorganic composite particles, or a mixture thereof) contained in the porous coating layer, as long as no oxidation and / or reduction reaction occurs within the operating voltage range of the electrochemical device, so as to be electrochemically stable. Substantially, as long as it is a particle phase that is generally applicable as a layer coated on an insulating microporous membrane (for improving the heat resistance of the separator, enhancing strength, improving electrolyte wettability, improving ionic conductivity, and / or increasing the dissociation degree of salts in the electrolyte, etc.) in a secondary battery, there is no particular limitation. As an example, inorganic particles may include metal oxides, metal carbides, metal alloys, metal phosphates, metal nitrides, or a mixture or complex thereof, etc. Substantially, oxides, carbides, nitrides, phosphates, or alloys containing one or more elements selected from the group consisting of Al, Ti, Ba, Pb, Zr, Sr, Hf, Li, Zn, Ce, Mg, Ca, Zn, Y, Nb, and Si may be mentioned, but are not limited thereto. At the same time or differently, the inorganic particles may be a dielectric with a dielectric constant of 5 or more, specifically, a dielectric with a dielectric constant of 10 or more. As an example, BaTiO3, Pb(Zr,Ti)O3 (PZT), Pb 1-x La x ZR 1-y Ti y O3 (PLZT, 0 < x < 1, 0 < y < 1), Pb(Mg 1 / 3 Nb 2 / 3 )O3 - PbTiO3 (PMN - PT), HfO2, SrTiO3, SnO2, CeO2, MgO, Mg(OH)2, NiO, CaO, ZnO, ZrO2, SiO2, Y2O3, Al2O3, AlOOH, Al(OH)3, SiC, and TiO2, or a mixture or complex thereof, etc., but are not limited thereto. At the same time or differently, the inorganic particles may be an inorganic ion conductor. Taking a lithium secondary battery as a representative example of an electrochemical device, lithium phosphate, lithium titanium phosphate (LipTiq(PO4)3, 0 < p < 2, 0 < q < 3), lithium aluminum titanium phosphate (Li a Al b Ti c (PO4)3, 0 < a < 2, 0 < b < 1, 0 < c < 3), (LiAlTiP) x O y glass - like (x < 4, 0 < y < 13), lithium lanthanum titanate (Li e LaFTiO3, 0 < e < 2, 0 < f < 3), lithium germanium thiophosphate (Li x Ge y Pz S w (where 0 < x < 4, 0 < y < 1, 0 < z < 1, 0 < w < 5), lithium nitride (Li k N l (where 0 < k < 4, 0 < l < 2), SiS2-based glass (Li m Si n SO (where 0 < m < 3, 0 < n < 2, 0 < o < 4), P2S5-based glass (Li x P y S z (where 0 < x < 3, 0 < y < 3, 0 < z < 7) or a mixture or a composite thereof, etc., but not limited thereto. The particulate phase may have a unimodal, bimodal or trimodal size distribution (diameter distribution), as long as the porosity based on the interstitial space of the particulate phase is at 20 to 80%, specifically, at a size level of 30 to 70%. As an example, the average diameter reaches 10 -1 micrometers (order) to 10 1 micrometers (order) level, but not limited thereto. The porous coating layer may be located on one surface or on opposite two surfaces of the porous membrane, and it may be a structure of two or more layers in which one or more of the substance of the stacked particulate phase, the size of the particulate phase, and the content of the particulate phase contained in the layer are different from each other, but not limited thereto. When the thickness of the porous membrane is 1, the thickness of the porous coating layer is at a level of 0.01 to 0.3, but not limited thereto.

[0100] The porous coating layer may further contain a binder (organic binder), and the binder can function to bond the above-mentioned particulate phase to the porous membrane. Any binder that is a commonly used polymer binder in the field of electrochemical devices is acceptable, whether it is an aqueous polymer binder or a non-aqueous polymer binder. As an example of the polymer binder, polyvinylidene fluoride (PVdF), polyvinylidene fluoride - hexafluoropropylene, polyvinylpyrrolidone, polyacrylonitrile, polyvinylidene fluoride - trichloroethylene, polyvinylidene fluoride - chlorotrifluoroethylene (PVdF-CTFE), polymethyl methacrylate, polyvinyl acetate, ethylene - vinyl acetate copolymer, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, carboxymethyl cellulose, acrylonitrile - styrene - butadiene copolymer, polyimide, polyvinyl alcohol, carboxymethyl cellulose, starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene - propylene - diene terpolymer (EPDM), sulfonated EPDM, styrene - butene rubber, fluororubber or a mixture thereof, etc., but not limited thereto. Based on 100 parts by weight of the particulate phase, the porous coating layer may contain 5 to 50 parts by weight, specifically, may contain 10 to 40 parts by weight of the binder, but not limited thereto.

[0101] In one embodiment, the crystalline metal salt may be located in one or more regions selected from the group consisting of the interface between the porous membrane and the porous coating layer, the interior of the porous coating layer, and the surface of the porous coating layer.

[0102] In the case where the metal salt is located at the interface between the porous membrane and the porous coating layer, the metal salt may be substantially uniformly located at the interface between the porous membrane and the porous coating layer, whereas at the interface between the porous membrane and the porous coating layer, the metal salt may be selectively (partially) located in the region connected to the voids of the porous coating layer (the interface region exposed by the open pores).

[0103] At the same time or independently therewith, the metal salt may be located inside the porous coating layer. In the case where the metal salt is located inside the porous coating layer, the metal salt may be located on the particle phase surface of the porous coating layer and / or the pore surface of the porous coating layer. In the case where the particles have porosity, the particle phase surface may include a surface based on pores, and the metal salt may be located partially or substantially uniformly on the particle phase surface. The interior of the porous coating layer may include the pore surface inside the porous coating layer. The pore surface is a surface that divides the pores inside the porous coating layer, and examples include the particle surface area other than the binder surface area, the area in contact between particles or between particles and the binder, etc. In the case where the metal salt is located on the pore surface of the porous coating layer, the metal salt may be located on part or all of the pore surface. In the case where it is located on part of the pore surface, it may be located on the pore surface adjacent to the surface (macroscopic outermost surface) of the porous coating layer.

[0104] At the same time or independently therewith, the metal salt may be located on the surface of the porous coating layer. The surface of the porous coating layer may refer to the outermost surface on a macroscopic scale. The metal salt may be located partially or substantially uniformly on the outermost surface of the porous coating layer.

[0105] As a substantial example, the metal salt may be located at the interface between the porous membrane and the porous coating layer, at the pore surface inside the porous coating layer, and at the surface (outermost surface) of the porous coating layer.

[0106] As another substantial example, the metal salt may be located on the surface (outermost surface) of the porous coating layer and in a partial region of the inner pore surface of the porous coating layer. In this case, the partial region of the inner pore surface may refer to the inner pore surface adjacent to the outermost surface. As an example, it may refer to a pore surface located in the following depth region, i.e., when the thickness of the porous coating layer is regarded as 1, the depth corresponding to 0.05 to 0.8, 0.1 to 0.7, 0.1 to 0.6, 0.1 to 0.5, 0.1 to 0.4, or 0.1 to 0.3 from the surface (outermost surface) of the porous coating layer toward the thickness direction of the porous coating layer, but is not necessarily limited thereto.

[0107] As another substantial example, the metal salt may be located on the surface of the particle phase of the porous coating layer. That is, the particle phase of the porous coating layer may be in a state coated with a metal salt. Therefore, the metal salt may be located in the region where the particle phase is located inside the porous coating layer, in the region where the particle phase is located on the outermost surface of the porous coating layer, and in the region where the particle phase is located at the interface between the porous membrane and the porous coating layer. From the perspective of the manufacturing method, the situation where the metal salt is located on the surface of the particle phase of the porous coating layer may correspond to the situation where, after the metal salt is adsorbed on (coated on) the particle phase of the porous coating layer, the porous coating layer is formed using the particle phase containing the adsorbed metal salt.

[0108] The above example is merely an example of how the metal salt of the composite membrane can be smoothly provided to the liquid electrolyte when the composite membrane contacts the liquid electrolyte. Obviously, the present invention is not limited to these specific examples.

[0109] The metal salt located on the surface of the porous membrane, the interface between the porous membrane and the porous coating layer, the interior of the porous coating layer and / or the surface of the porous coating layer may be adsorbed in a form selected from molecular form to cluster form, but is not necessarily limited thereto.

[0110] The content of the metal salt contained in the composite diaphragm can be determined by considering the concentration of the liquid electrolyte injected into the electrochemical device provided with the composite diaphragm (injection concentration) and the concentration of the required electrolyte (design concentration). That is, the composite diaphragm may contain at least a metal salt corresponding to the difference between the total amount of solute required for the design concentration (total moles) and the total amount of solute contained in the injected liquid electrolyte (total moles), but it is also possible to contain more than these metal salts. As a substantial example, the design concentration can be 1.1M or more, 1.3M or more, 1.5M or more, 1.7M or more, 1.9M or more, 2.0M or more, 2.1M or more, or 2.2M or more, and can be 6.0M or less, 5.5M or less, 5.0M or less, 4.5M or less, 4.0M or less, 3.5M or less, 3.0M or less, or 2.5M or less, but is not limited thereto. As an example, the design concentration can be 1.1M to 6.0M concentration, 1.3 to 5.5M concentration, 1.5 to 5.5M concentration, 1.7 to 5.5M concentration, 1.9 to 5.5M concentration, 2.0 to 5.5M concentration, 2.1 to 5.5M concentration, 2.2 to 5.5M concentration, 1.5 to 3.0M concentration, 1.5 to 2.5M concentration. The injection concentration can be 0.3 to 1.0M concentration, 0.5 to 1.0M concentration or 0.8 to 1.0M concentration. At this time, the concentration of the salt in the design concentration and the injection concentration refers to the total concentration of the salt (electrolyte salt) of the metal ion (metal ion participating in the electrochemical reaction) dissolved in the electrolyte. In this regard, it is obvious that the electrolyte salt dissolved in the injected electrolyte and the metal salt provided by the composite diaphragm can be the same or different salts. The composite separator may include at least a metal salt that increases the concentration of the liquid electrolyte from the injected concentration to a designed concentration or more by contacting the injected liquid electrolyte.

[0111] Among them, the present invention lists a high concentration electrolyte of 1.1 to 6.0M as a more effective example, but this is only an example of the technical advantages of the composite diaphragm according to a specific example of the present invention. Since wettability is a big problem in high concentration electrolytes, and the electrolyte injection process is complicated and time-consuming, conventional liquid electrolytes with a design concentration of less than 1M or about 1M can also be formed inside the electrochemical device through the composite diaphragm according to a specific example of the present invention. As an extreme example, inside the electrochemical device, the solvent can be converted into a liquid electrolyte through the composite diaphragm according to a specific example of the present invention. That is, in the electrochemical device manufacturing process, a solvent for the liquid electrolyte is added, and the metal salt of the composite diaphragm inside the electrochemical device is dissolved in the added solvent, thereby generating a liquid electrolyte inside the electrochemical device.

[0112] As a substantial and non-limiting example, the metal salt content in the composite separator may be 0.1 to 5.0 mg / cm², as the mass of the metal salt per unit area of ​​the porous substrate. 2 , 0.2 to 4.0 mg / cm 2 , 0.2 to 3.0 mg / cm 2 .

[0113] In one specific example, the metal salt contained in the composite separator can be any solute (electrolyte salt) of a liquid electrolyte used in electrochemical devices. Specifically, the metal salt contained in the composite separator can have a molecular weight (g / mole) of 1000 or less, specifically 500 or less, and more specifically 400 or less. In practice, the metal salt can have a molecular weight of 10 or more, 20 or more, or 30 or more. Furthermore, the number of anions per molecule of the metal salt contained in the composite separator can be 1 to 4, specifically 1 to 3, and more specifically 1 to 2.

[0114] As a substantial example, the metal ions participating in the electrochemical reaction of the electrochemical device are used as active ions, and the metal salt can provide active ions in the form of cations and can provide a selected from Cl - Br - , I - 、NO3 - 、N(CN)2 - 、BF4 - 、ClO4 - PF6 - 、(CF3)2PF4 - 、(CF3)3PF3 - 、(CF3)4PF2 - 、(CF3)5PF - 、AsF6 - 、BF6 - 、SbF6 - 、(CF3)6P - CF3SO3 - CF3CF2SO3 - 、AlO3 - 、AlCl4 - 、C4F9SO(CF3SO2)2N - 、(CF3CF2SO2)2N - 、(FSO2)2N - 、(C2F5SO3)2N - 、(F3CF2SO2)2N - 、(C2F5SO2)2N - 、(CF3SO2)2N -CF3CF2(CF3)2CO - 、(CF3SO2)2CH - 、(SF5)3C - 、(CF3SO2)3C - CF3(CF2)7SO3 - CF3CO2 - 、CH3CO2 - 、SCN - 、B 10 Cl 10 - 、C4BO8 - 、B(C2O4)2 - 、CH3SO3 - The salt containing one or more ions as an anion (counter ion of the active ion) may be, in particular, a sulfonyl group-containing crystalline metal salt as described later, but is not necessarily limited thereto. Considering the specific composition of the liquid electrolyte involved, the metal salt contained in the composite separator can be any salt of the active ion required in the combination. In the case of a lithium secondary battery as a representative electrochemical device, the active ion may be a lithium ion.

[0115] As mentioned above, the applicant has confirmed that a specific metal salt, specifically a sulfonyl metal salt (a sulfonyl crystalline metal salt) can impart a high degree of flame retardancy to a porous substrate during an in-depth study of a composite diaphragm used as an electrolyte salt supply source inside an electrochemical device to increase the concentration of the injected liquid electrolyte. It has also been confirmed that while ensuring this flame retardancy, the electrochemical properties can also be greatly improved. In order to popularize large and medium-sized electrochemical devices, priority must be given to safety in preventing explosions and fires. The applicant has confirmed that this safety is firmly ensured by a sulfonyl metal salt (a sulfonyl crystalline metal salt). After playing the role of a salt supply source for a liquid electrolyte in an electrochemical device, this safety (flame retardancy) is also achieved by forming a high concentration of a sulfonyl crystalline metal salt in a diaphragm (porous substrate) at a higher concentration, or by fixing a sulfonyl crystalline metal salt to a diaphragm (porous substrate) by a foreign substance.

[0116] Based on this discovery, a composite separator according to one embodiment of the present invention may include a porous substrate and a crystalline metal salt containing a sulfonyl group (a crystalline metal salt containing a sulfonyl group). The crystalline metal salt containing a sulfonyl group ensures flame retardancy without compromising electrochemical properties, or may even improve them.

[0117] Although not limited to these explanations, in the case of a crystalline metal salt containing a sulfonyl group that is fixed to a porous substrate by a foreign substance, or that is located in the porous substrate or fixed by itself in the form of a salt (crystalline salt) without dissociating into ions, a coordination structure is formed by the interaction between the active cations and solvent molecules of the liquid electrolyte injected into the electrochemical device and the sulfonyl groups of the anions. Therefore, while having very high volatility, the flammable solvent molecules are suppressed from becoming free solvents, thereby imparting flame retardancy to the porous substrate. In particular, when the solvent of the liquid electrolyte includes a carbonate solvent, an ether solvent, or a carbonate and ether solvent, the aggregation of two to three or more active metal cations (active ions) and sulfonyl groups with solvent molecules into clusters is accelerated, thereby making it easier to form a coordination structure.

[0118] Furthermore, the sulfonyl-containing crystalline metal salt not only secures flame retardancy but also significantly improves ionic conductivity through the porous substrate. While not necessarily limited to this explanation, the crystalline metal salt provided by the composite separator forms localized, high-concentration ion clusters, allowing for smooth ion migration within and near the clusters via the Grotthus mechanism, thereby improving the metal ion mobility coefficient. Furthermore, through a synergistic effect with the vehicle mechanism based on solvent molecules, metal ion migration is accelerated, thereby improving metal ion ionic conductivity.

[0119] Preferably, the sulfonyl group-containing crystalline metal salt is substantially uniformly located on the surface region of the porous substrate in order to achieve stable flame retardancy. Therefore, as a favorable example considering flame retardancy, the sulfonyl group-containing metal salt is substantially uniformly located on the surface (outermost surface) of the porous substrate, or substantially the entire thickness of the porous substrate is considered to be t p m, it may be located 0.05 to 0.3 t from one surface toward the thickness direction of the porous substrate. pm The surface area of ​​the area.

[0120] As a substantial example, when the porous substrate includes a porous film without a separate coating layer, the sulfonyl group-containing crystalline metal salt can be substantially uniformly located on the surface of the porous film.

[0121] As a substantial example, in the case where the porous substrate includes a porous membrane and a porous coating layer located on at least one side surface of the porous membrane, the crystalline metal salt containing a sulfonyl group is substantially uniformly located on the surface (outermost surface) of the porous coating layer, or substantially, the crystalline metal salt containing a sulfonyl group is uniformly located on the surface (outermost surface) of the porous coating layer and a portion of the inner region of the porous coating layer, or substantially, it can be uniformly located on the surface (outermost surface) of the porous coating layer, the interior of the porous coating layer (inner pore surface), and the region where the interface between the porous membrane and the porous coating layer is in contact with the voids of the porous coating layer. In this case, the inner portion of the porous coating layer where the crystalline metal salt containing a sulfonyl group is located is similar to or the same as described above.

[0122] However, these examples are merely advantageous examples of how flame retardancy can be stably imparted to porous substrates. Obviously, the present invention is not limited to the specific location of the sulfonyl group-containing crystalline metal salt or the object to which the sulfonyl group-containing crystalline metal salt imparts flame retardancy. As described below regarding the coating solution, the sulfonyl group-containing crystalline metal salt can be placed in any component of an electrochemical device that comes into direct contact with the liquid electrolyte, thereby imparting flame retardancy to that component.

[0123] According to one embodiment of the composite separator, the crystalline metal salt containing a sulfonyl group may have a molecular weight (g / mole) of 1000 or less, specifically 500 or less, and more specifically 400 or less, and may be substantially 10 or greater, 20 or greater, or 30 or greater. Furthermore, the number of anions per molecule of the crystalline metal salt containing a sulfonyl group may be 1 to 4, specifically 1 to 3, and more specifically 1 to 2.

[0124] According to a specific example of a composite separator, the crystalline metal salt containing a sulfonyl group may be one or more compounds selected from the group consisting of compounds satisfying the following chemical formulas 1 to 4. When the composite separator includes compounds satisfying the following chemical formulas 1 to 4, while ensuring flame retardancy, wettability with the liquid electrolyte can be improved, and smoother ion flow can be achieved.

[0125] [Chemical Formula 1]

[0126]

[0127] In Chemical Formula 1, A + Is a monovalent cation, R1 is F, CFH2, CF2H or C n F 2n+1 , wherein n is a natural number greater than or equal to 1, specifically, a natural number from 1 to 5, and more specifically, a natural number from 1 to 3.

[0128] (Chemical Formula 2)

[0129]

[0130] In Chemical Formula 2, A 2+ is a divalent cation, R1 is F, CFH2, CF2H or C n F 2n+1 , wherein n is a natural number greater than or equal to 1, specifically, a natural number from 1 to 5, and more specifically, a natural number from 1 to 3.

[0131] (Chemical Formula 3)

[0132]

[0133] In Chemical Formula 3, A + is a monovalent cation, R1 and R2 are each independently F, CFH2, CF2H or C n F 2n+1 , wherein n is a natural number greater than or equal to 1, specifically, a natural number from 1 to 5, and more specifically, a natural number from 1 to 3.

[0134] (Chemical Formula 4)

[0135]

[0136] In Chemical Formula 4, A 2+ is a divalent cation, R1 and R2 are each independently F, CFH2, CF2H or C n F 2n+1 , wherein n is a natural number greater than or equal to 1, specifically, a natural number from 1 to 5, and more specifically, a natural number from 1 to 3.

[0137] In Chemical Formulas 1 to 4, A + or A 2+ As long as it is a univalent metal ion or a divalent metal ion that can be used as a counterpart of a sulfonyl anion component. As a non-limiting example, a univalent cation is an example of one or more metals selected from alkali metals, as an example, lithium ions or sodium ions, and a divalent cation is an example of one or more metals selected from alkaline earth metals and post-transition metals, as an example, zinc ions, etc., but is not necessarily limited thereto. At the same time or independently of this, in chemical formulas 1 to 4, R1 and R2 can each independently be selected from F, CF3 and CF2CF3. As a substantial example, the sulfonyl-containing crystalline metal salt can be one or more selected from lithium trifluoromethanesulfonate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(perfluoroethanesulfonyl)imide, zinc trifluoromethanesulfonate, bis[bis(trifluoromethylsulfonyl)imide]zinc, etc.

[0138] In Chemical Formulas 1 to 4, the monovalent or divalent cations can be active metal ions that participate in the electrochemical reaction of the electrochemical device, thereby improving wettability while significantly increasing the conductivity of ions migrating between the two electrode regions through the composite separator. As a representative example of an electrochemical device, in the case of a lithium secondary battery, the sulfonyl group-containing crystalline metal salt can be one or more substances selected from compounds satisfying Chemical Formulas 1 and 3. In this case, the monovalent cation can be a lithium ion.

[0139] In order to achieve flame retardancy and further stably improve wettability and / or ion conductivity by the sulfonyl group-containing crystalline metal salt, the crystalline metal salt may be fixed to the porous substrate via a foreign substance different from the metal salt.

[0140] However, the fixation of metal salt can not be interpreted as being limited to the case of sulfonyl-containing crystalline metal salt. As mentioned above, even if the composite diaphragm plays the role of the metal salt supply source of liquid electrolyte, the metal salt may also be in the state of being fixed on the porous substrate by external factors (foreign substances) other than porous substrate and metal salt. However, considering the effect as salt supply source, the fixation of metal salt can be achieved by the following external factors (foreign substances), i.e., under the state that the composite diaphragm is in contact with the liquid electrolyte, the fixation based on external factors (foreign substances) is released, and the metal salt is soluble in the liquid electrolyte. Therefore, based on the non-contact state with the liquid electrolyte, the metal salt provided as the solute of the electrolyte in the composite diaphragm may also be in the state of being fixed on the porous substrate.

[0141] However, for the sulfonyl group-containing crystalline metal salt, fixation of the metal salt should be interpreted as also including fixation by a foreign substance (keeping the metal salt in a state where it cannot be freely dissolved in the liquid electrolyte) even in a state of contact with the liquid electrolyte.

[0142] As a specific example, a metal salt (including a sulfonyl group-containing crystalline metal salt) can be immobilized by one or more binder components selected from linear polymers and cross-linked polymers. When the binder component is a linear polymer or a cross-linked polymer, the designed concentration of the metal salt in the composite separator can be stably maintained due to the suppression of Brownian motion, thereby ensuring the desired physical property stability over a long period of time.

[0143] As a substantial example, the linear polymer may be selected from polyvinylidene fluoride (PVdF), polyvinylidene fluoride-co-hexafluoropropylene (PVdF-co-HFP), polymethyl methacrylate (PMMA), polystyrene (PS), polyvinylacetate (PVA), polyacrylonitrile (PAN), polyethylene oxide (PEO), polyvinyl fluoride (PVD), polyvinyl fluoride-co-hexafluoropropylene (PVD-co-HFP), polymethyl methacrylate (PMMA), polystyrene (PS), polyvinyl acetate (PVA), polyacrylonitrile (PAN), polyethylene oxide (PEO), polyvinyl fluoride (PVD), polyvinyl fluoride-co-hexafluoropropylene (PVD-co-HFP ... oxide, PEO), polyacetylene, polythiophene, polypyrrole, poly(p-phenylene), poly(phenylenevinylene), poly(phenylenesulfide), polyaniline, and polyethylenedioxythiophene (PEDOT), or a mixture of two or more thereof, but not limited thereto.

[0144] When the adhesive component is a cross-linked polymer, it is advantageous to uniformly impart desired physical properties to desired portions of the porous substrate. Specifically, when the adhesive component is a cross-linked polymer, the metal salt can be fixed by curing the curing component in a state mixed with the metal salt (in the presence of the metal salt), wherein the curing component may have curability that converts into the adhesive component upon curing.

[0145] As an example, the curing component can be selected from one or more of the monomers, oligomers and prepolymers with curability. In this case, the curing in the curability can be thermal curing, chemical curing and / or light curing, but is not limited thereto. In essence, the curing component can be a monomer with curability (crosslinkable monomer), and the adhesive component can be a crosslinked polymer. More essentially, the fixation of the metal salt is achieved by crosslinking the crosslinkable monomers by an initiator in a state where the metal salt and the crosslinkable monomers are mixed.

[0146] As a specific example, the crosslinkable monomer used as a curing component can be a monomer having two or more functional groups or a mixed monomer formed by mixing a monomer having two or more functional groups with a monomer having one functional group. However, it is clear that the present invention does not limit the number of functional groups of the crosslinkable monomer. As a substantial example, the crosslinkable monomer that can form a crosslinked polymer through crosslinking can be one or more crosslinkable monomers selected from acrylate monomers, acrylic acid monomers, sulfonic acid monomers, phosphoric acid monomers, perfluorinated monomers, and acrylonitrile monomers, but is not limited thereto. As a substantial example of a monomer having two or more functional groups, one or a mixture of two or more selected from polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, ethoxylated trimethylolpropane triacrylate, ethoxylated trimethylolpropane trimethacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, etc. can be cited, but is not limited thereto. As a substantial example of a monomer having one functional group, one or a mixture of two or more selected from the group consisting of methyl methacrylate, ethyl methacrylate, butyl methacrylate, methyl acrylate, butyl acrylate, ethylene glycol methyl ether acrylate, ethylene glycol methyl ether methacrylate, acrylonitrile, vinyl acetate, vinyl chloride, and vinyl fluoride can be cited, but are not limited thereto. As a more substantial example, a crosslinkable monomer can include, but are not limited to, ethoxylated trimethylolpropane triacrylate alone, or a mixture of ethoxylated trimethylolpropane triacrylate and other monomers having two or more functional groups, and one or more of the aforementioned monomers having one functional group.

[0147] A composite membrane according to one embodiment can include a crystalline metal salt in the form of a coating layer.

[0148] In detail, the composite diaphragm may include a porous substrate and a coating layer located on at least one side surface of the porous substrate and comprising the above-mentioned crystalline metal salt. In more detail, the composite diaphragm may include a porous substrate and a coating layer, wherein the coating layer is located on at least one side surface of the porous substrate and comprises the above-mentioned crystalline metal salt and a polymer component selected from the above-mentioned linear polymer and cross-linked polymer. The coating layer may correspond to a case where the adhesive component for fixing the metal salt forms a continuous connected continuum, but is not necessarily interpreted as being limited to this case. Regardless of whether a continuum of an adhesive component is formed, in the manufacturing method, after uniformly coating the desired surface portion of the porous substrate with a liquid (coating liquid) containing a metal salt and an adhesive component or a curing component, a process of at least volatilizing the solvent is performed, and a curing process is performed when necessary, so that the metal salt and the adhesive component coexist in the desired portion of the porous substrate, which can be interpreted as the metal salt existing in the form of a coating layer. At this time, preferably, the solvent used is one or more solvents selected from C1-C3 lower alcohol solvents, ketone solvents and carbonate solvents that make the above-mentioned metal salts and linear polymers and cross-linked polymers easy to dissolve and can be completely volatilized and removed by simple drying. Examples of C1-C3 lower alcohol solvents include methanol, ethanol, isopropyl alcohol, etc., examples of ketone solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, etc., and examples of carbonate solvents include ethylene carbonate, propylene carbonate, fluoroethylene carbonate, dimethyl carbonate, diethyl carbonate, etc. At this time, the coating liquid is the liquid phase raw material used when preparing the coating liquid (based on room temperature), and in addition to one or more curable components selected from the group of monomers, oligomers and prepolymers with curability and converted into adhesive components by curing, it can only contain the above-mentioned solvents. Thus, after drying to volatilize and remove the solvent, a solid phase coating film can be manufactured.

[0149] The coating layer may be located on the surface of at least one side (the electrode side serving as the positive electrode side or the negative electrode side) of the porous substrate, each of the two surfaces of the porous substrate facing each other, or the entire surface of the porous substrate, but is not limited thereto. The present invention does not exclude the situation where the coating layer is selectively located in a preset area on one side surface of the porous substrate.

[0150] Specifically, the coating layer is located on the surface (outermost surface) of the porous substrate, or can be located on the outermost surface of the porous substrate and the pore surface of the open pores of the porous substrate. More specifically, the total thickness of the porous substrate is considered to be t pm When the porous substrate is formed, it may be located 0.05 to 0.3 t from one surface (outermost surface) toward the thickness direction of the porous substrate. pmIn the case where the coating layer is present on the pore surface, the size of the pores in the surface region may be partially reduced, but the pore structure inherent to the porous substrate can be basically maintained, that is, the pores will not be closed (destroyed). In terms of maintaining the pore structure inherent to the porous substrate, preferably, the coating layer comprises a cross-linked polymer. This is because, when a liquid comprising a cross-linkable monomer and a metal salt is used to form the coating layer, an extremely thin and uniform coating layer can be formed on the outermost surface of the porous substrate, or on the outermost surface and the pore surface, thereby substantially preventing the pore structure of the porous substrate from being destroyed.

[0151] As a substantial example, when the porous substrate comprises a porous membrane without an additional coating layer, the coating layer can be directly bonded to the surface of the porous membrane. From a method perspective, direct bonding can be achieved by applying a liquid (coating liquid) containing a metal salt and a bonding component and / or a curing component, followed by a phase change (solidification) of the bonding component due to evaporation of the solvent and / or by curing of the curing component.

[0152] As a substantial example, in the case where the porous substrate includes a porous membrane and a porous coating layer located on at least one surface of the porous membrane, the coating layer (coating layer containing a metal salt) is directly bonded to the surface (outermost surface) of the porous coating layer, or directly bonded to the pore surface belonging to the surface (outermost surface) of the porous coating layer and the internal partial region (surface region) of the porous coating layer, or can be directly bonded to the surface (outermost surface) of the porous coating layer, the interior of the porous coating layer (internal pore surface) and the interface between the porous membrane and the porous coating layer, which is in contact with the voids of the porous coating layer. At the same time or independently, the coating layer (coating layer containing a metal salt) can be located between the porous membrane and the porous coating layer. In this case, the internal partial region (surface region) of the porous coating layer where the coating layer is located is similar or identical to the above.

[0153] When the metal salt is present in the form of a coating layer, the composite separator may contain 5 to 70 parts by weight, 5 to 50 parts by weight, 5 to 40 parts by weight, 5 to 30 parts by weight, or 10 to 25 parts by weight of a foreign substance, specifically a binder, more specifically one or more polymers selected from linear polymers and cross-linked polymers, based on 100 parts by weight of the metal salt. The content of these foreign substances is sufficient to stably fix the metal salt contained in the composite separator.

[0154] In the case of having the metal salt in the form of a coating layer, preferably, the porous substrate includes 0.3 mg / cm 2 The above metal salts can be used to stably exhibit flame retardancy even when the composite diaphragm is in direct contact with flame. Specifically, the metal salt content can be 0.3 to 5.0 mg / cm 2, 0.3 to 4.0 mg / cm 2 , 0.3 to 3.0 mg / cm 2 , 0.3 to 2.5 mg / cm 2 , 0.3 to 2.0 mg / cm 2 , 0.4 to 1.5 mg / cm 2 , 0.5 to 1.4 mg / cm 2 , or 0.5 to 1.2 mg / cm 2 .

[0155] At the same time or independently therewith, in order to ensure flame retardancy while preventing degradation of the characteristics of the electrochemical cell by introducing a metal salt in the form of a coating layer, the projected phase metal salt content as the mass of the metal salt per unit area is 0.3 to 6.0 mg / cm 2 , specifically 0.3 to 5.0 mg / cm 2 , 0.3 to 4.0 mg / cm 2 , specifically 0.5 to 3.0 mg / cm 2 , 0.4 to 2.0 mg / cm 2 , 0.5 to 1.5 mg / cm 2 , 0.7 to 1.4 mg / cm 2 , 0.8 to 1.3 mg / cm 2 , or 0.8 to 1.2 mg / cm 2 .

[0156] In this case, the projected phase metal salt content can be represented by the unit area of ​​the projected image viewed downwardly from the widest surface of the porous substrate, and the mass of the metal salt per unit area can be represented by the total mass of the metal salt in the region of the porous substrate corresponding to the unit area of ​​the projected image. For example, assuming that the two opposing surfaces of the porous substrate are the first and second surfaces, and the mass of the metal salt per unit area of ​​the first surface is A and the mass of the metal salt per unit area of ​​the second surface is B, the metal salt content is A or B, and the projected phase metal salt content is A+B. Obviously, the metal salt content of each different surface can also fall within the above range.

[0157] When a metal salt (preferably a crystalline metal salt containing a sulfonyl group) is introduced in the form of a coating layer, the composite diaphragm provided in the electrochemical device can stably exhibit flame retardancy in a harsh environment, and can stably exhibit flame retardancy in a manner that does not change the physical properties during the expected life of the electrochemical device. Even when one or more crystalline metal salts containing a sulfonyl group selected from the compounds satisfying the above chemical formulas 1 to 4 are introduced in the form of a coating layer, in essence, regardless of the use environment, excellent wettability and / or improved metal ion conductivity can be maintained during the expected life of the electrochemical device. Among them, it is obvious that whether to fix the metal salt can be selectively determined by considering the specific use of the electrochemical device and the important physical properties required for the use.

[0158] As described above, the composite diaphragm according to one specific example of the present invention may include a metal salt (first metal salt) used as a salt supply source in the electrolyte, and the composite diaphragm according to another specific example may include a sulfonyl-containing crystalline metal salt (second metal salt) fixed in a state of a porous substrate to ensure stable and long-term stable flame retardancy. At this time, the present invention cannot be interpreted as being limited to the case of a metal salt used as a salt supply source or a sulfonyl-containing crystalline metal salt in a fixed state. That is, the composite diaphragm according to the present invention may include a porous substrate and a metal salt (first metal salt) used as a salt supply source and a sulfonyl-containing crystalline metal salt (second metal salt) fixed in a state of a porous substrate, respectively. As an example, the surface (or surface area) of the porous substrate has a coating layer comprising a sulfonyl-containing crystalline metal salt, so that flame retardancy can be ensured, and the porous substrate with the coating layer containing the metal salt includes a first metal salt in a form that can be dissolved when in contact with a liquid medium, which can be used as a salt supply source. For those skilled in the art working in the field of electrochemical devices or diaphragms, based on the above-mentioned content regarding the role of the salt supply source or the flame retardancy imparted by the sulfonyl group-containing crystalline metal salt fixed and positioned in the form of a coating layer, etc., various deformation situations can be easily deduced, as shown in one example, so that the role of the salt supply source and the physical properties of flame retardancy can be achieved at the same time. This is based on the degree of easy modification of the above-mentioned content of the aforementioned composite diaphragm, and is therefore included in the scope of the present invention.

[0159] Compared with the flame retardancy ensured by the specific material of the porous substrate to improve thermal stability by introducing a flame retardant substance developed in the past (for example, introducing an inorganic coating layer), the principle of ensuring flame retardancy by metal salts is different. Although not necessarily limited to this explanation, the flame retardancy achieved in the composite diaphragm according to a specific example of the present invention can be flame retardancy ensured by suppressing the free solvent of the high concentration of the liquid electrolyte based on the state change of the solvent molecules of the liquid electrolyte containing a sulfonyl crystalline metal salt (for example, forming a coordination structure with the metal salt) and / or the high concentration of the liquid electrolyte in contact with the diaphragm. At this time, it is obvious that the high concentration of the liquid electrolyte in contact with the diaphragm can refer to the high concentration caused by the formation of the concentration gradient of the electrolyte salt between the diaphragm and the electrode due to the metal salt provided by the diaphragm. Among them, the metal salt that can show flame retardancy cannot be interpreted as being limited to the sulfonyl crystalline metal salt. The reason is that even if it is a metal salt that does not contain a sulfonyl group, a metal salt can be provided from the diaphragm to the liquid electrolyte and a high concentration electrolyte gradient can be formed on the diaphragm side, thereby suppressing the free solvent and showing flame retardancy. However, compared to other metal salts, when a high-concentration electrolyte gradient is formed using a sulfonyl group-containing crystalline metal salt, the ionic conductivity through the separator is greatly improved, thereby improving the capacity retention, high-rate characteristics, high-temperature characteristics, and / or cycle characteristics. Among them, even if the metal salt contained in the composite separator exists in a form soluble in the liquid phase medium and acts as a salt supply source for the electrolyte within the electrochemical device, it is more advantageous for the metal salt contained in the composite separator to be a sulfonyl group-containing crystalline metal salt, but the present invention is not necessarily limited to this.

[0160] Therefore, the present invention provides a flame-retardant separator based on the specific technical concept of the present invention.

[0161] The flame retardant membrane according to the present invention (flame retardant membrane I) is immersed in the following reference electrolyte for 1 minute and then recovered. After recovery, the gravity direction is made parallel to the in-plane direction of the membrane. When the following flame retardancy test is performed at a time point where no droplets fall from the membrane to the bottom within 1 minute, the membrane has flame retardancy in that no flame is generated.

[0162] Reference electrolyte: a mixed solvent of ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1, a lithium salt of LiPF6, a LiPF6 concentration of 1 M, and a temperature of 25°C ± 5°C.

[0163] Flame retardancy test: The length of the flame in the atmosphere is 5 to 10 cm, the tip temperature of the flame is 1000 to 1500°C, and the length of the flame region not in contact with the diaphragm when the flame is applied to the diaphragm is 50 to 80% of the length of the flame in the atmosphere, and the movement speed of the flame in contact with the diaphragm is 1 to 5 cm / sec.

[0164] At this time, the flame movement can be a movement along the diameter (maximum diameter) passing through the center of the diaphragm so that 30 to 90% of the diameter is in contact with the flame. The area in contact with the flame may be repeatedly contacted 1 to 2 times during the flame movement, but is not necessarily limited to this flame movement and contact.

[0165] At this time, no flame is generated in the separator means that no flame other than the flame applied from the outside for the flame retardancy test is generated, and it means that the separator has no flame almost at the same time as the externally applied flame is removed.

[0166] At this time, as far as the flame retardancy test is concerned, the diaphragm can be placed on the bottom surface of the flame retardant container at the test time point. When the shortest spacing distance between the diaphragm and the flame applied from the outside is greater than 0.5 cm, greater than 1 cm, greater than 5 cm, and actually greater than 10 cm, it can be considered that the flame has been removed, but it is not necessarily limited to this.

[0167] When the flame retardancy test using the above-mentioned reference electrolyte is performed, the flame retardancy exhibited may be the flame retardancy possessed by the above-mentioned composite diaphragm, specifically the flame retardancy possessed by the composite diaphragm comprising a crystalline metal salt containing a sulfonyl group. The flame retardancy test using the above-mentioned reference electrolyte may be the state before the composite diaphragm is used for the diaphragm of an electrochemical device, the state during use, or the state after use. As a substantial example, the flame retardancy test using the above-mentioned reference electrolyte may be the state before the composite diaphragm is used for the diaphragm of an electrochemical device, that is, the state when the composite diaphragm is not in contact with a liquid electrolyte. As another substantial example, in the flame retardancy test using the above-mentioned reference electrolyte, the diaphragm that has been set (used) in the electrochemical device can be separated and recovered.

[0168] Independently of this, when the diaphragm obtained according to the following steps is subjected to the following flame retardancy test when the diaphragm is set in an electrochemical device using any liquid electrolyte, the flame retardant diaphragm according to the present invention (flame retardant diaphragm II) has flame retardancy that no flame is generated in the diaphragm.

[0169] Steps: 1) Remove the seal of the electrochemical device and open at least one end, cut off the connection between the electrode ear (tap) used for electrical connection to the outside world and the positive electrode-diaphragm-negative electrode complex, and thus recover the electrode complex; 2) Separate and recover the diaphragm from the recovered electrode complex; 3) After recovering the diaphragm, make the gravity direction parallel to the in-plane direction of the diaphragm, and perform the following flame retardancy test at the time point (initial time point) when no droplets fall from the diaphragm to the bottom within one minute.

[0170] Flame retardancy test: The flame length in the atmosphere is 5 to 10 cm, the flame tip temperature is 1000 to 1500°C, and the length of the flame area not in contact with the diaphragm when the flame is applied to the diaphragm is 50 to 80% of the flame length in the atmosphere. The flame movement speed in contact with the diaphragm is 1 to 5 cm / sec. In this case, the flame movement can be along a diameter (maximum diameter) passing through the center of the diaphragm so that 30 to 90% of the diameter is in contact with the flame. The area in contact with the flame may be repeatedly contacted 1 to 2 times during the flame movement, but is not necessarily limited to such flame movement and contact.

[0171] The flame-retardant separator (I or II) may contain the sulfonyl group-containing crystalline metal salt and exhibit flame retardancy through the sulfonyl group-containing crystalline metal salt. Therefore, the flame-retardant separator includes all of the above contents related to the sulfonyl group-containing crystalline metal salt in the composite separator.

[0172] Alternatively, the flame-retardant separator (I or II) exhibits flame retardancy through a concentration gradient of an electrolyte salt (caused by a metal salt supplied to the liquid electrolyte via a composite separator). Specifically, flame retardancy can be exhibited by suppressing free solvent (achieved by increasing the concentration of the liquid electrolyte adjacent to the separator). Therefore, the flame-retardant separator can include all of the above-mentioned features related to the structure serving as a salt supply source in the composite separator.

[0173] Alternatively, the flame-retardant separator (I or II) can exhibit flame retardancy by fixing a sulfonyl group-containing crystalline metal salt (second metal salt) on a porous substrate and a metal salt (first metal salt) provided on the porous substrate in a form that is soluble when in contact with a liquid medium containing a solvent.

[0174] The composite diaphragm or flame-retardant diaphragm described above may be a diaphragm that does not contain a liquid phase component, i.e., a dry-type diaphragm. A dry-type diaphragm means that, when the mass of the manufactured composite diaphragm is defined as W0 and the mass of the composite diaphragm after being placed in 25°C air for one hour is defined as W1h, the mass reduction rate (W0 - W1h) / W0 × 100 (%) is less than 1%, specifically less than 0.5%, and substantially reaches 0%. In this case, the term "0%" essentially means that there is no mass change within the measurement error range of the mass measuring equipment, taking into account measurement error.

[0175] The present invention includes an electrochemical device comprising the composite separator described above.

[0176] The present invention includes an electrochemical device comprising the above-mentioned flame-retardant separator (I or II).

[0177] Independently of this, the present invention includes the following electrochemical device, which includes a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode, and an electrolyte, and when the components of the electrode and the separator serving as the positive electrode or the negative electrode are analyzed, the concentration of the elemental component derived from the metal salt is different.

[0178] In this case, the phenomenon in which the concentration of the elemental components derived from the metal salt in the separator is relatively higher than that in the electrode can be achieved by the metal salt fixed to the separator (corresponding to the composite separator described above), specifically, by the composite separator provided in the electrochemical device. According to a preferred embodiment, the metal salt can be the sulfonyl group-containing crystalline metal salt described above, and the difference in concentration of the elemental components derived from the metal salt can be caused by the sulfonyl group-containing crystalline metal salt fixed to the porous substrate.

[0179] Independently of this, the present invention includes an electrochemical device comprising a positive electrode, a negative electrode, a separator interposed between the positive and negative electrodes, and an electrolyte containing a metal salt, wherein analysis of the components of the positive or negative electrode and the separator reveals different concentrations of the elemental component derived from the metal salt. In essence, the concentration of the elemental component derived from the metal salt in the separator may be higher than the concentration of the elemental component derived from the metal salt in the electrode.

[0180] According to one example, the phenomenon in which the concentration of the elemental component derived from the metal salt in the separator is relatively higher than that in the electrode can be achieved when the metal salt dissolved in the electrolyte originates from the separator. Specifically, the phenomenon in which the concentration of the elemental component derived from the metal salt in the separator is relatively higher than that in the electrode can be achieved when the separator includes a metal salt that is soluble in the electrolyte (in a soluble form) when in contact with the electrolyte, thereby enabling the electrolyte to contain the metal salt derived from the separator.

[0181] When the separator contains a metal salt that is soluble in the electrolyte, after the metal salt is provided as a solute (electrolyte salt) by contact with a liquid electrolyte or a liquid medium containing a solvent injected during the manufacturing process, the concentration of the metal salt in the porous substrate can be maintained at a relatively high level compared to the positive and negative electrodes for a long period of time. Due to the concentration gradient formed by the metal salt derived from the separator, the electrolyte components in the separator, positive electrode, and negative electrode have different surface tensions. In a battery without external forces such as a separate convection force, the concentration of the metal salt derived from the separator can be maintained at a relatively high level compared to the positive and negative electrodes for a long period of time. Due to this concentration gradient, the concentration of the elemental components derived from the metal salt can be relatively high in the separator compared to the electrodes.

[0182] Furthermore, when the metal salt is a sulfonyl-containing metal salt, the surface wettability of the separator can be significantly improved through the interaction between the sulfonyl group and the active metal ions and the solvent in the electrolyte. Therefore, when the metal salt is a sulfonyl-containing metal salt, the concentration difference between the elemental components derived from the metal salt on the separator surface and the elemental components derived from the metal salt on the electrode surface can be greater.

[0183] As described above, in order to prepare the desired concentration of electrolyte within the electrochemical device, when the separator contains a metal salt (including a crystalline metal salt containing a sulfonyl group) that is soluble in the electrolyte, there may also be a significant concentration difference of the elemental components derived from the metal salt between the electrode and the separator.

[0184] At this time, the electrolyte, specifically, the liquid electrolyte may contain one, two, three or four or more metal salts as solutes, and the metal salt of the electrolyte (electrolyte salt, solute) may be composed of a metal salt derived from the diaphragm (hereinafter, the third metal salt), or may contain a metal salt derived from the diaphragm (hereinafter, the third metal salt) and a metal salt not derived from the diaphragm (a metal salt already contained in the electrolyte injected from the outside when manufacturing the electrochemical device, hereinafter, the fourth metal salt).

[0185] As an example, the electrolyte may contain the third metal salt alone. In this case, when assembling the electrochemical device, a solvent containing no electrolyte salt (which may contain known additive components as needed) may be added from the outside.

[0186] As another example, the electrolyte includes a third metal salt and a fourth metal salt, and the third metal salt and the fourth metal salt may be the same metal salt. When the third metal salt and the fourth metal salt are the same metal salt (for example, metal salt A), the concentration of metal salt A in the electrolyte within the electrochemical device after assembly of the electrochemical device may be higher than the concentration of metal salt A in the electrolyte introduced during assembly of the electrochemical device.

[0187] As another example, the electrolyte includes a third metal salt and a fourth metal salt, and the third metal salt and the fourth metal salt may be dissimilar metal salts. In the case where the third metal salt and the fourth metal salt are dissimilar metal salts, the total metal salt (electrolyte salt) concentration (the sum of the third metal salt concentration and the fourth metal salt concentration) in the electrolyte within the electrochemical device after assembly of the electrochemical device may be higher than the metal salt (electrolyte salt) concentration (the concentration of the fourth metal salt) in the electrolyte introduced during assembly of the electrochemical device. Furthermore, the electrolyte after assembly of the electrochemical device may include metal salts (electrolyte salts, solutes) that are not injected as the electrolyte.

[0188] Independently of this, the present invention includes the following electrochemical device, wherein the above-mentioned electrochemical device includes a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode, and an electrolyte containing a metal salt, and when the components of the electrode serving as the positive electrode or the negative electrode and the separator are analyzed, the concentrations of the elemental components derived from the metal salt as the elemental components derived from the metal salt are different, and the concentration of the elemental components derived from the metal salt of the electrode is higher than the concentration of the elemental components derived from the metal salt of the separator.

[0189] Hereinafter, the case where the metal salt dissolved in the electrolyte originates from the electrode (positive electrode or negative electrode) and a concentration difference of the elemental component derived from the metal salt occurs between the electrode surfaces of the electrode will be described in more detail. According to one example, with respect to the phenomenon that the concentration of the elemental component derived from the metal salt of the electrode is relatively higher than that of the separator, this can be achieved when the metal salt dissolved in the electrolyte originates from the electrode. In detail, with respect to the phenomenon that the concentration of the elemental component derived from the metal salt of the electrode is relatively higher than that of the separator, this can be achieved when the electrode includes a metal salt that is soluble in the electrolyte (in a soluble form) when in contact with the electrolyte, so that the electrolyte includes a metal salt derived from the electrode.

[0190] In this case, in the composite separator described above, the porous substrate may correspond to the electrode active material layer (negative electrode active material layer or positive electrode active material layer) of the electrode, and the surface or surface region of the electrode active material layer may correspond to the surface or surface region of the porous substrate. Therefore, in an electrochemical device in which the concentration of the elemental component derived from the metal salt in the electrode is higher than the concentration of the elemental component derived from the metal salt in the separator, the composite separator described above uses the electrode active material layer in place of the porous substrate, and includes all of the contents described for the composite separator.

[0191] As a specific example, the electrode may contain a metal salt in a form that is soluble in a liquid medium containing a solvent or in a fixed form. That is, the metal salt may be adsorbed and / or fixed to the electrode active material layer. In essence, the metal salt may be located in part or the entire region of the electrode active material layer (negative electrode active material layer and / or positive electrode active material layer).

[0192] The partial area of ​​the electrode active material layer may refer to the surface area of ​​the electrode active material layer. The surface area of ​​the electrode active material layer may refer to the area where the thickness of the electrode active material layer is regarded as t am When the surface in contact with the electrolyte is 0.05 to 0.3t toward the current collector, am area, but is not necessarily limited to it.

[0193] When located in the entire area of ​​the electrode active material layer, the metal salt may be located in the pore surface area based on the pores (substantially open pores) inside the electrode active material layer, the active material surface area (negative electrode active material surface or positive electrode active material surface) area of ​​the particle phase of the electrode active material layer, the pore surface area and the entire active material surface area, but is not necessarily limited to this.

[0194] In terms of the manufacturing method, the metal salt can be impregnated or fixed to a partial area or the entire area of ​​the electrode active material layer by coating the electrode active material layer with a coating solution. In contrast, in terms of the manufacturing method, after the electrode active material particles are coated with the metal salt, the electrode active material layer is manufactured by using an electrode active material coated with the metal salt, so that the metal salt can be impregnated in the entire area of ​​the electrode active material layer. In contrast, the metal salt is put into an electrode slurry (if necessary, further comprising a conductive material) comprising an electrode active material and a binder, and the electrode active material layer is manufactured by coating the electrode slurry comprising the metal salt, so that the metal salt can be impregnated in the entire area of ​​the electrode active material layer.

[0195] Experimentally, the concentration of the elemental component derived from the metal salt in the electrode and separator can be measured according to the following steps (II) and / or (III) by the following analytical method. The following steps (II) and / or (III) are steps that can eliminate the influence of the charge or discharge state or the previous use state of the electrochemical device.

[0196] Step (II): 1) removing the seal of the electrochemical device and opening at least one end, cutting off the connection between the electrode ear for electrical connection to the outside world and the positive electrode-diaphragm-negative electrode complex, thereby recovering the electrode complex; curing the recovered electrode complex at 60°C for more than 24 hours using a molding epoxy resin, and recovering the electrode complex molded in the epoxy resin; for a sample in which the molded electrode complex is cut into a cross-sectional specimen with a thickness of less than 20 μm using an ion beam, analyzing it by neutron depth profiling analysis to calculate the concentration gradient of active metal ions in the cross-section of the electrode complex.

[0197] Step (III): 1) removing the seal of the electrochemical device and opening at least one end, severing the connection between the electrode ear for electrical connection to the outside world and the positive electrode-diaphragm-negative electrode complex, thereby recovering the electrode complex; 2) analyzing the recovered electrode complex by the following method: a solution in which the separator, positive electrode, and negative electrode were each immersed in anhydrous deuterated dimethyl sulfoxide for 24 hours.

[0198] Analytical method: Analysis is performed using one or more methods selected from fluorine nuclear magnetic resonance spectroscopy (F-NMR), chlorine nuclear magnetic resonance spectroscopy (Cl-NMR), inductively coupled plasma mass spectrometry (ICP-MS), proton nuclear magnetic resonance spectroscopy (H-NMR) and X-ray photoelectron spectroscopy (XPS).

[0199] As an analytical method, when analyzing the components in the diaphragm, positive electrode, and negative electrode, it is obviously necessary to keep the analytical conditions the same. In addition to the listed analytical methods, it is also possible to perform analysis using analytical methods that can be used for surface elemental analysis. The present invention is not limited by the specific type of analytical method.

[0200] Furthermore, when an analytical method is used for analysis, each sample is repeatedly measured 5 times or more, specifically, 10 times or more, and the average value is calculated.

[0201] Furthermore, when the difference between the concentration of the elemental component derived from the metal salt in the diaphragm and the concentration of the elemental component derived from the metal salt in the electrode is greater than or equal to the known (determined) error range of the above-mentioned analytical method and analytical device, it can be interpreted as a significant difference. When there is a significant difference, it can be judged that the concentrations of the elemental component derived from the metal salt between the diaphragm and the electrode are different from each other.

[0202] Specifically, the concentrations in the separator, the positive electrode, and the negative electrode can be determined by the following method.

[0203] The concentrations and ratios of the metal salts can be determined by F-NMR and Cl-NMR analysis of a diluted liquid sample of the electrolyte dissolved in the separator, positive electrode, and negative electrode. Furthermore, the ratio of solvent molecules and the content of additives can be determined by H-NMR analysis, if necessary.

[0204] Alternatively, the electrolyte determined by the above analysis may be directly prepared and the above analysis may be repeated, thereby further including a step of verifying the analysis.

[0205] In terms of experiments, the difference in the concentration of the lithium salt in the separator, the positive electrode, and the negative electrode may be directly confirmed by analysis in step (III).

[0206] The elemental component derived from the metal salt may be an element constituting a metal salt (electrolyte salt) dissolved in the electrolyte of the electrochemical device, and there is no (multiple) element in the porous substrate of the electrode (specifically, the electrode active material layer) and the diaphragm. In other words, considering the specific materials of the diaphragm, positive electrode and negative electrode of the electrochemical device, the elemental component derived from the metal salt may be an element that is only present in the metal salt dissolved in the electrolyte. At this time, it is obvious that when there are two or more different metal salts (electrolyte salts) dissolved in the electrolyte, the elemental component derived from the metal salt is limited for each metal salt (electrolyte salt), and each metal salt (electrolyte salt) is subjected to elemental analysis by an analytical method. As a substantial example, when the metal salt is a crystalline metal salt containing a sulfonyl group, the elemental component derived from the metal salt may be a sulfur component. When there are two or more different metal salts (electrolyte salts) dissolved in the electrolyte, the concentrations of the elemental component derived from the metal salt between the diaphragm surface and the electrode surface may be different from each other for one or more metal salts (electrolyte salts).

[0207] However, the present invention is not limited to elemental components derived from metal salts. In the case where the elemental components derived from metal salts cannot be used to track the metal salts, as an example, when all elements contained in the metal salt are present in an electrode or a porous substrate, it is obvious that the concentration or content of the binding state of the elements derived from the metal salt and / or the functional groups derived from the metal salt (functional groups present in the metal salt) can be used instead of the elemental components derived from the metal salt. This corresponds to an example of a simple change based on the present invention.

[0208] In terms of manufacturing method, the electrochemical device according to the present invention includes a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode, an electrolyte containing a metal salt and a shell. When manufacturing the electrochemical device, when the concentration of the metal salt (electrolyte salt) of the electrolyte (injected electrolyte) injected into the shell is used as the injection concentration, the metal salt concentration of the electrolyte (used electrolyte) sealed and included in the shell is higher than the injection concentration.

[0209] This is because as the injected electrolyte comes into contact with the separator inside the housing, the metal salt contained in the separator dissolves in the injected electrolyte, turning the injected electrolyte into the working electrolyte. Experimentally, this transition from injected electrolyte to working electrolyte can be demonstrated by the difference in concentration of the elemental components derived from the metal salt between the electrode surface and the separator surface.

[0210] According to a specific example of an electrochemical device, metal ions that participate in the electrochemical reaction of the electrochemical device are used as active ions. The metal ions of the metal salt contained in the separator may include active ions, but are not necessarily limited thereto.

[0211] According to a specific embodiment of the electrochemical device, the molar concentration of the salt of the active ion included in the electrolyte, specifically, the molar concentration of the salt of the active ion included in the electrolyte may be 0.5 to 6.0M, 0.5 to 5.0M, 0.5 to 4.0M, 0.5 to 3.0M, 0.5 to 2.5M, 0.5 to 1.2M, 0.7 to 6.0M, 0.8 to 6.0M, 0.9 to 6.0M, 1.0 to 6.0M, 1.1 to 6.0M, 1.2 to 6.0M, 1 .3 to 6.0M, 1.4 to 6.0M, 1.5 to 6.0M, 1.6 to 6.0M, 1.7 to 6.0M, 1.8 to 6.0M, 1.9 to 6.0M, 2.0 to 6.0M, 2.1 to 6.0M, 2.2 to 6.0M, 2.3 to 6.0M, 2.4 to 6.0M, 2.5 to 6.0M, 0.7 to 5.0M, 0.8 to 5.5M, 0.9 to 5.0M, 1.0 to 5.0M, 1.1 to 5.0M, 1.2 to 5.0M, 1 .3 to 5.0M, 1.4 to 5.5M, 1.5 to 5.0M, 1.6 to 5.0M, 1.7 to 5.0M, 1.8 to 5.0M, 1.9 to 5.0M, 2.0 to 5.0M, 2.1 to 5.0M, 2.2 to 5.0M, 2.3 to 5.0M, 2.4 to 5.0M, 2.5 to 5.0M, 0.7 to 4.0M, 0.8 to 4.0M, 0.9 to 4.0M, 1.0 to 4.0M, 1.1 to 4.0M, 1.2 to 4.0M, 1 .3 to 4.0M, 1.4 to 4.0M, 1.5 to 4.0M, 0.7 to 1.2M, 0.9 to 1.2M, 0.8 to 2.5M, 1.0 to 2.5M, 1.2 to 2.5M, 1.3 to 2.5M, 1.4 to 2.5M, 1.5 to 2.5M, 1.6 to 2.5M, 1.7 to 2.5M, 1.8 to 2.5M, 1.9 to 2.5M, 1.5 to 2.2M, 1.7 to 2.2M, or 1.5 to 2.0M levels, but are not limited to these.

[0212] At this time, as described above, a concentration gradient may be formed in which the concentration of the metal salt increases in the separator or electrode that supplies the metal salt to the electrolyte. As the active (metal) ions move from one electrode to the other through the separator, the concentration of the active ion salt in the electrolyte can be interpreted as the maximum concentration in the concentration gradient, that is, the maximum concentration among the salt concentrations in the electrolyte contained (impregnated) in the positive electrode, the negative electrode, and the separator, and should not be interpreted as the average active ion salt concentration in the electrolyte.

[0213] In terms of metal ion ion conductivity, the electrochemical device according to the present invention includes a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode, and an electrolyte. The metal ions participating in the electrochemical reaction are used as active ions. The ion conductivity of the separator in a state of being wetted by the electrolyte can be 0.30 mS / cm or more, 0.32 mS / cm or more, 0.34 mS / cm or more, 0.36 mS / cm or more, 0.38 mS / cm or more, 0.40 mS / cm or more, 0.42 mS / cm or more, 0.44 mS / cm or more, 0.46 mS / cm or more. In some embodiments, the ionic conductivity may be 2.00 mS / cm or less, 0.48 mS / cm or less, 0.50 mS / cm or less, 0.52 mS / cm or less, 0.54 mS / cm or less, 0.56 mS / cm or less, 0.58 mS / cm or less, 0.60 mS / cm or less, 0.61 mS / cm or less, 0.62 mS / cm or less, 0.63 mS / cm or less, 0.64 mS / cm or less, 0.65 mS / cm or less, 0.66 mS / cm or less, 0.67 mS / cm or less, 0.68 mS / cm or less, 0.69 mS / cm or less, or 0.70 mS / cm or less. In practice, the ionic conductivity may be 2.00 mS / cm or less, but is not limited thereto.

[0214] Furthermore, in conjunction with the above-mentioned ionic conductivity, the ion mobility coefficient of the active ions of the separator in a wetted state with the electrolyte may be 0.30 or more, 0.32 or more, 0.34 or more, 0.36 or more, 0.38 or more, 0.40 or more, 0.42 or more, 0.44 or more, 0.46 or more, 0.48 or more, 0.50 or more, 0.52 or more, 0.54 or more, 0.56 or more, 0.58 or more, 0.60 or more, 0.62 or more, 0.64 or more, 0.66 or more, or 0.68 or more. In practice, the ion mobility coefficient may be 1.50 or less, but is not limited thereto.

[0215] As described above, in the case of a composite separator, when the metal salt is a sulfonyl group-containing crystalline metal salt (especially one or more metal salts selected from the compounds satisfying Chemical Formulas 1 to 4), the ionic conductivity of metal ions in the separator can be greatly improved.

[0216] It should be noted that, in a high concentration electrolyte environment, metal salts can also improve the metal ion conductivity. In essence, the ion conductivity of the diaphragm in a state wetted by the electrolyte, further, the ion mobility coefficient of the active ion can be the ion conductivity and ion mobility coefficient of the electrolyte under a high concentration electrolyte. A high concentration electrolyte can refer to a high concentration liquid electrolyte in which the concentration of the salt of the active ion dissolved in the electrolyte (when the salt of the active ion is different from two or more kinds, the total concentration of the salt of the active ion) is 1M or more. Specifically, the concentration of the salt of the active ion in the high concentration electrolyte can be 1.0M or more, 1.1M or more, 1.2M or more, 1.3M or more, 1.4M or more, 1.5M or more, 1.6M or more, 1.7M or more, 1.8M or more, 1.9M or more, 2.0M or more, 2.1M or more, 2.2M or more, 2.3M or more, 2.4M or more or 2.5M or more, in essence, it can be 6M concentration or less. The salt of the active ion dissolved in the electrolyte can be any substance commonly used as an electrolyte salt in the field of electrochemical devices. Obviously, the salt of the active ion dissolved in the electrolyte can include the aforementioned metal salt of the composite separator, but it is not necessary that the metal salt in the composite separator be different from the aforementioned metal salt. When a salt concentration gradient exists in the electrolyte within the electrochemical device, the concentration of the salt of the active ion in the high-concentration electrolyte can be based on the maximum concentration value in the concentration gradient. In fact, it can be based on the highest concentration value obtained by measuring the concentration of the salt of the active ion in the positive electrode, negative electrode, and separator.

[0217] The separator in each of the aforementioned electrochemical devices is the same as or similar to the composite separator described above. Therefore, the electrochemical device includes all of the aforementioned features of the composite separator. The composite separator contacts the electrolyte to provide a metal salt to the electrolyte, and exhibits the aforementioned flame retardancy or ion conductivity properties based on the metal salt remaining in the porous substrate. In contrast, the composite separator exhibits the aforementioned flame retardancy or ion conductivity properties because it contains a metal salt fixed to the porous substrate.

[0218] Considering the specific type of electrochemical device, the positive electrode, negative electrode, electrolyte, and housing in each of the above-mentioned electrochemical devices may be those commonly used in the above-mentioned electrochemical devices. However, when the separator serves as a salt supply source for the electrolyte, the electrolyte may obviously be a more highly concentrated electrolyte than the injected electrolyte.

[0219] Taking a lithium secondary battery, a representative example of an electrochemical device, as an example, the positive electrode may include a positive electrode collector and a positive electrode active material layer located on at least one side of the positive electrode collector, the negative electrode may include a negative electrode collector and a negative electrode active material layer located on at least one side of the negative electrode collector, the electrolyte may be a liquid electrolyte in which a lithium salt is dissolved in a solvent, and the shell may be a bag-shaped shell, a cylindrical shell or a square shell.

[0220] In detail, as for the positive electrode active material contained in the positive electrode active material layer, a material that can reversibly deintercalate / intercalate lithium ions can be used, as long as it is an electrode material used for the positive electrode of a conventional lithium secondary battery. As an example, the positive electrode active material can be LiMO2 (M is one or more transition metals selected from Co and Ni); LiMO2 (M is one or more transition metals selected from Co and Ni) substituted by one or more heterogeneous elements selected from Mg, Al, Fe, Ni, Cr, Zr, Ce, Ti, B and Mn, or coated with oxides of these heterogeneous elements; layered oxides, for example, representatively, Li x Ni α Co β M γ O2 (a real number of 0.8≤x≤1.5, a real number of 0.7≤α≤0.9, a real number of 0.05≤β≤0.35, a real number of 0.01≤γ≤0.1, α+β+γ=1, M is one or more elements selected from the group consisting of Mg, Sr, Ti, Zr, V, Nb, Ta, Mo, W, B, Al, Fe, Cr, Mn and Ce) or Li x Ni a Mn b Co c M d O2 (a real number of 0.9≤x≤1.1, a real number of 0.3≤a≤0.6, a real number of 0.3≤b≤0.4, a real number of 0.1≤c≤0.4, a real number of 0≤d≤0.4, a+b+c+d=1, and is one or more elements selected from the group consisting of Mg, Sr, Ti, Zr, V, Nb, Ta, Mo, W, B, Al, Fe, Cr and Ce); oxides of a spinel structure, for example, representatively, Li a Mn 2-x M x O4 (M is one or more elements selected from Al, Co, Ni, Cr, Fe, Zn, Mg, B and Ti, a real number with 1≤a≤1.1, and a real number with 0≤x≤0.2) or Li4Mn5O 12 ; or olivine-structured phosphate substances, for example, representatively, LiMPO4 (M is Fe, Co, Mn); or mixtures thereof, but not limited thereto.

[0221] In detail, the negative electrode active material of the negative electrode active material layer can use a material commonly used for the negative electrode of a lithium secondary battery, and the negative electrode active material can be a material that can be embedded in lithium. As an example, the negative electrode active material can be selected from lithium (metallic lithium), easily graphitized carbon, difficultly graphitized carbon, graphite, silicon, Sn alloy, Si alloy, Sn oxide, Si oxide, Ti oxide, Ni oxide, Fe oxide (FeO), lithium titanium oxide (LiTiO2, Li4Ti5O 12 ), one or more substances in a mixture or a complex thereof, but not limited thereto.

[0222] The positive electrode active material layer and the negative electrode active material layer may further include an organic binder, respectively. The binder may be a substance commonly used for the electrode of a lithium secondary battery, as long as it does not chemically react with the electrolyte and can bind the active materials and the active materials to the collector. As a specific example, for the positive electrode active material layer and the negative electrode active material layer binder, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride-trichloroethylene copolymer, polymethyl methacrylate, polyacrylonitrile, polyvinyl pyrrolidone, polyvinyl acetate, polyethylene-vinyl acetate copolymer, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, carboxymethyl cellulose, styrene-butadiene copolymer, acrylonitrile-styrene-butadiene copolymer, polyimide, polytetrafluoroethylene or a mixture thereof can be listed independently. However, it is obvious that the present invention is not limited by the binder material.

[0223] The positive electrode collector or negative electrode collector can be independently a positive electrode collector or negative electrode collector used in a conventional lithium secondary battery. Specifically, the positive electrode collector or negative electrode collector can be a material with excellent electrical conductivity and chemical stability during battery charge and discharge. Specifically, the positive electrode collector or negative electrode collector can be a conductive material such as graphite, graphene, titanium, copper, platinum, aluminum, nickel, silver, gold aluminum, or carbon nanotubes, but the present invention is not limited thereto.

[0224] If desired, the positive electrode active material layer or the negative electrode active material layer may further include a conductive material. To improve the conductivity of the active material layer, the conductive material can be any conductive material commonly used in lithium secondary batteries. Specific examples of the conductive material include, but are not limited to, conductive carbon bodies (e.g., carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, or mixtures thereof); conductive fibers (e.g., carbon fibers or metal fibers); and conductive nanostructures (e.g., carbon nanotubes or graphene).

[0225] The electrolyte may be a liquid electrolyte. In conventional lithium secondary batteries, it is sufficient that it is a non-aqueous electrolyte that smoothly conducts ions involved in the charging and discharging of the battery. As an example, the non-aqueous electrolyte may include a non-aqueous solvent and a lithium salt. The non-aqueous organic solvent may be a single carbonate, ester, ether or ketone, or a mixed solvent thereof. In particular, when a single carbonate solvent, an ether solvent, or a mixed solvent thereof is used as a mixed solvent, it may be more conducive to forming a coordination structure through interaction with the active metal ions and the sulfonyl group. Specifically, the non-aqueous organic solvent may be ethylene carbonate, propylene carbonate, 1,2-butenyl carbonate, 2,3-butenyl carbonate, 1,2-pentenyl carbonate, 2,3-pentenyl carbonate, vinylene carbonate, ethylene ethylene carbonate, fluoroethylene carbonate, dimethyl carbonate, diethyl carbonate, bis(2,2,2-trifluoroethyl) carbonate, dipropyl carbonate, dibutyl carbonate, ethyl methyl carbonate, 2,2,2-trifluoroethyl methyl carbonate, methylpropyl carbonate, ethylenepropylene carbonate, Esters, 2,2,2-trifluoroethylpropyl carbonate, methyl isopropyl carbonate, methyl formate, ethyl formate, propyl formate, butyl formate, dimethyl ether, diethyl ether, dipropyl ether, ethyl methyl ether, methyl propyl ether, ethyl propyl ether, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, butyl butyrate, gamma-butyrolactone, 2-methyl-gamma-butyrolactone, 3-methyl-gamma-butyrolactone, 4-methyl- γ-Butyrolactone, γ-thiobutyrolactone, γ-ethyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone, σ-valerolactone, γ-caprolactone, ε-caprolactone, β-propiolactone, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, trimethyl phosphate, triethyl phosphate, tris(2-chloroethyl) phosphate, tris(2,2,2-trifluoroethyl) phosphate, tripropyl phosphate, triisopropyl phosphate, tributyl phosphate, trihexyl phosphate, triphenyl phosphate, phosphoric acid Tritolyl ester, methyl ethylene phosphate, ethyl ethylene phosphate, dimethyl sulfone, ethyl methyl sulfone, methyl trifluoromethyl sulfone, ethyl trifluoromethyl sulfone, methyl pentafluoroethyl sulfone, ethyl pentafluoroethyl sulfone, bis(trifluoromethyl) sulfone, bis(pentafluoroethyl) sulfone, trifluoromethyl pentafluoroethyl sulfone, trifluoromethyl nonafluorobutyl sulfone, pentafluoroethyl nonafluorobutyl sulfone, sulfolane, 3-methylsulfolane, 2-methylsulfolane, 3-ethylsulfolane, 2-ethylsulfolane or a mixed solvent thereof, but are not limited thereto. As an example, the solvent of the electrolyte may also be an ionic liquid.

[0226] The lithium salt may include the case where the metal ions of the metal salt in the aforementioned composite separator are lithium ions, but is not limited thereto. It can be any lithium salt generally used to smoothly conduct ions involved in battery charging and discharging.

[0227] Optionally, it is apparent that the electrolyte may also include known additives, for example, additives for forming a solid electrolyte interface (SEI) film (for example, halogen-substituted or unsubstituted cyclic carbonate compounds, nitrile compounds, phosphate compounds, borate compounds, sulfate compounds, sultone compounds, lithium salt compounds).

[0228] The electrochemical device may be a primary battery or a secondary battery capable of performing an electrochemical reaction. More specifically, examples include, but are not limited to, lithium primary batteries, lithium secondary batteries, lithium-sulfur batteries, lithium-air batteries, sodium batteries, aluminum batteries, magnesium batteries, calcium batteries, zinc batteries, zinc-air batteries, sodium-air batteries, aluminum-air batteries, magnesium-air batteries, calcium-air batteries, supercapacitors, dye-sensitized solar cells, fuel cells, lead storage batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and alkaline batteries.

[0229] The present invention includes an electrochemical module, wherein the electrochemical module comprises the electrochemical device described above as a single cell, with two or more cells arranged and electrically connected to each other. Obviously, the electrochemical module can have a cell arrangement and structure commonly used in the electrochemical device field, and can also include conventional cooling components, such as a cooling plate.

[0230] The present invention includes a device that provides power through the electrochemical device or the electrochemical module. As an example, the device can be a device that requires large or medium-sized power, such as an electric vehicle or a hybrid vehicle.

[0231] The present invention includes a coating solution for coating a structural component of an electrochemical device in contact with an electrolyte. The coating solution of the present invention is a coating solution for coating a structural component of an electrochemical device in contact with an electrolyte in addition to an electrolyte, and contains a metal salt.

[0232] The metal salt contained in the coating solution is coated on the structural components of the electrochemical device and can supply the metal salt to the electrolyte when the electrochemical device is assembled (manufactured). However, the role of the metal salt in the coating solution is not limited to being a metal salt supply source for the electrolyte.

[0233] The metal salt in the coating solution according to the present invention may be the same as or similar to the metal salt in the aforementioned composite separator. Therefore, the coating solution includes all the above contents related to the metal salt in the composite separator.

[0234] For example, the coating solution may include a sulfonyl-containing metal salt. By coating a component of an electrochemical device with the coating solution containing the sulfonyl-containing metal salt, the coated component can serve as a salt source for the electrolyte, or, simultaneously or independently, impart flame retardancy to the component.

[0235] As another example, the coating solution may contain one or more metal salts selected from the compounds satisfying Chemical Formulas 1 to 4. Inclusion of such a metal salt can provide flame retardancy or function as a salt supply source, and simultaneously or independently thereof, can improve electrolyte wettability, or, simultaneously or independently thereof, can improve ionic conductivity of active ions.

[0236] Preferably, the solvent of the coating solution is one or more solvents selected from C1-C3 lower alcohol solvents, ketone solvents, and carbonate solvents, which facilitates dissolution of the metal salt and, if necessary, the adhesive component (for example, a linear polymer and / or a cross-linked polymer) and can be completely evaporated and removed by simple drying. Examples of C1-C3 lower alcohol solvents include methanol, ethanol, and isopropanol; examples of ketone solvents include acetone, methyl ethyl ketone, and methyl isobutyl ketone; and examples of carbonate solvents include ethylene carbonate, propylene carbonate, fluoroethylene carbonate, dimethyl carbonate, and diethyl carbonate. In this case, when the coating solution does not contain an adhesive component, the coating solution may contain only the above-mentioned solvents as liquid phase raw materials (based on room temperature). In contrast, when the coating solution contains an adhesive component, the coating solution may contain only the above-mentioned solvent as a liquid phase raw material (based on room temperature), or may contain only a solvent and a curing component, wherein the above-mentioned curing component is selected from one or more of the group consisting of curable monomers, oligomers and prepolymers and is converted into an adhesive component by curing.

[0237] Structural components are any components that come into direct contact with an electrolyte (specifically, a liquid electrolyte) when assembled into an electrochemical device. For example, the structural components may be one or more selected from the group consisting of a positive electrode, a negative electrode, a separator, and a housing. Furthermore, when there are two or more structural components, each of them can be coated with the coating solution.

[0238] Specifically, as structural components, there can be listed the positive electrode surface including a pore-based surface (including the positive electrode active material layer surface based on the pore surface), the negative electrode surface including a pore-based surface (including the negative electrode active material layer surface based on the pore surface), the diaphragm surface including a pore-based surface (or the above-mentioned surface area in the aforementioned composite diaphragm), the inner surface of the shell, etc., but are not limited to these.

[0239] As described above, the coating solution contains the above-mentioned metal salt and may also contain one or more curing components selected from the group consisting of curable monomers, oligomers and prepolymers, linear polymers or their mixtures. When containing curing components, it may also contain additives, including initiators.

[0240] The curing component, initiator, and linear polymer in the coating solution are the same or similar to the curing component and initiator that are converted into the aforementioned adhesive component and cross-linked polymer in the aforementioned composite separator. The coating solution includes all of the aforementioned components related to the adhesive component and curing component in the composite separator. In this case, the weight ratio of metal salt to adhesive component can correspond to the weight ratio of metal salt to curing component in the coating solution.

[0241] The concentration of the metal salt in the coating solution may be at the level of 0.1 to 5 M, but is not necessarily limited thereto.

[0242] By applying a coating solution containing a metal salt and a curing component to a structural member and drying the coating solution, a coating layer containing a crystalline metal salt fixed to the structural member can be formed.

[0243] The coating solution may further comprise inorganic particles, organic particles, organic-inorganic composite particles, or mixed particles thereof. Specifically, the coating solution may comprise a metal salt and a particle phase as inorganic particles, organic particles, organic-inorganic composite particles, or mixed particles thereof. In this case, the coating solution may further comprise the above-mentioned curing component or organic binder, or a curing component and an organic binder.

[0244] The coating solution contains a particle phase that is identical or similar to the particle phase of the porous coating layer of the composite separator, and the coating solution contains an organic binder that is identical or similar to the binder in the porous coating layer of the composite separator. The coating solution includes all of the aforementioned components related to the particle phase and binder of the inorganic particles, organic particles, organic-inorganic composite particles, or mixed particles thereof used in the composite separator.

[0245] When the coating solution further includes a particulate phase, the coating solution may include 10 to 1000 parts by weight, specifically 50 to 1000, and more specifically 100 to 500 parts by weight, of a metal salt, based on 100 parts by weight of the particulate phase. When the metal salt content relative to the particulate phase is within the above-described range, the crystalline metal salt can be uniformly distributed on the surface of the particulate phase of the porous coating layer produced using the coating solution. Furthermore, the crystalline metal salt can be uniformly distributed on the surface of the particulate phase and between the binding component and / or binder, thereby facilitating flame retardancy and / or improving ionic conductivity.

[0246] Based on 100 parts by weight of the particle phase, the coating solution may contain 1 to 30 parts by weight, specifically 5 to 10 parts by weight, of a binder, a curing component, or a binder and a curing component, but is not limited thereto. However, within the above range, the porosity based on the gaps between the particles of the particle phase can be maintained, and it is beneficial to stably fix the particle phase to the porous membrane through the binder and / or curing component. In this case, the coating solution may contain 5 to 30% by weight of the particle phase, but is not limited thereto. Considering the specific method of coating the solution, it can be a weight percentage that can exhibit appropriate coating characteristics.

[0247] A coating layer comprising a metal salt and a particulate phase is formed on a porous membrane using a coating solution comprising a metal salt and a particulate phase, thereby forming a porous coating layer comprising a metal salt on the porous membrane. In this case, the coating solution may be a coating solution for preparing a separator. The porous membrane is the same as or similar to the porous membrane in the aforementioned composite separator. Therefore, the coating solution includes all of the aforementioned contents related to the porous membrane in the composite separator.

[0248] The present invention includes a method for producing an electrode (positive electrode or negative electrode) using the coating solution. In this case, the coating solution may be a solution for coating an electrode (positive electrode or negative electrode) of an electrochemical device.

[0249] Specifically, the method for manufacturing an electrode according to the present invention includes applying the above-mentioned coating solution to the electrode active material layer of the electrode. In this case, the electrode active material layer can be a positive electrode active material layer or a negative electrode active material layer. Obviously, the electrode active material layer can be manufactured by conventional methods known in the art, for example, by applying a slurry of an electrode active material including a particle phase and a binder (if necessary, further comprising a conductive material) to a current collector and drying and rolling.

[0250] In terms of coating the coating solution, when giving priority to the role of the metal salt supply source, it is sufficient to achieve coating in such a way that the metal salt content that increases the concentration of the liquid electrolyte from the injection concentration to the designed concentration or above is located in the electrode active material layer. As a substantial example, the metal salt content as the mass of the metal salt per unit area of ​​the electrode active material layer can be in the range of 0.1 to 5.0 mg / cm 2 Apply in a horizontal manner.

[0251] At the same time or independently, when the priority is to improve flame retardancy or ionic conductivity, the metal salt content as the mass of the metal salt per unit area of ​​the electrode active material layer is used as a reference, so that the metal salt dissolved in the electrolyte and remaining in the electrode active material layer or the metal salt in a state of being fixed in the electrode active material layer is 0.3 to 5.0 mg / cm 2 , 0.3 to 4.0 mg / cm 2 , 0.3 to 3.0 mg / cm2 , 0.3 to 2.5 mg / cm 2 , 0.3 to 2.0 mg / cm 2 , 0.4 to 1.5 mg / cm 2 , 0.5 to 1.4 mg / cm 2 , or 0.5 to 1.2 mg / cm 2 Apply in a horizontal manner.

[0252] The coating solution can be applied by one or more methods selected from spin coating, roll coating, spray coating, dip coating, flow coating, doctor blade, dispensing, inkjet printing, offset printing, stencil printing, screen printing, pad printing, gravure printing, reverse gravure printing, gravure offset printing, flexography printing, stencil printing, imprinting, xerography, slit coating, rod coating, and roll-to-roll coating, but is not limited thereto.

[0253] After the coating solution is applied, a step of applying energy to the coating material of the coating solution may be performed. The applied energy may be heat energy, light energy, or heat energy and light energy, and the application of heat energy and light energy may include applying them sequentially or simultaneously.

[0254] This energy application may be for the purpose of more rapidly volatilizing and removing (drying) the solvent in the coating material described below, and / or, in the case where the coating solution contains a curable component, converting the curable component contained in the coating material into an adhesive component. Obviously, when applying the energy for drying and the energy for converting the coating material into an adhesive component, the type of energy applied may be different: heat energy, light energy, or heat and light energy. Obviously, the energy for converting the curable component into an adhesive component may be applied sequentially after the energy for drying.

[0255] When energy is applied for drying, heat and / or light known as heat rays (eg, near-infrared light) may be applied to an extent sufficient to promote volatilization of the solvent contained in the coating material, without damaging the components.

[0256] When applying the energy for curing the curing component, the specific curability of the curing component contained in the coating is taken into account, so that the above-mentioned curing component is cured or can promote the curing by applying heat, light or heat and light. As an example, when the curing component is a heat-curing type, thermal energy that can promote or cause curing can be applied. As another example, when the curing component is a light-curing type, light comprising the wavelength band required for curing the added curing component can be applied. As a substantial example, when the curing component has ultraviolet (UV) curability, light comprising ultraviolet (UV) can be applied.

[0257] However, the energy application for drying can be selectively performed when necessary. As an example, drying can be performed by room temperature evaporation drying, hot air drying or cold air drying, heating drying (thermal energy or ultraviolet energy, etc.), etc., and drying can be appropriately changed according to the design of the electrode manufacturing process.

[0258] As a variation of the above-mentioned electrode manufacturing method, after preparing an electrode active material coated with a metal salt by mixing an electrode active material with a metal salt solution and drying it, an electrode slurry of the electrode active material coated with a metal salt, a binder, etc. (including a conductive material when necessary) can be applied to a collector and dried and rolled to manufacture a metal salt-containing electrode.

[0259] As another variation of the above-mentioned electrode manufacturing method, a metal salt-containing electrode can be manufactured by coating an electrode slurry (including a conductive material if necessary) of an electrode active material, a metal salt, a binder, etc. on a current collector and drying and rolling. These variations of introducing a metal salt into the electrode active material layer are also examples that can be easily derived by those skilled in the art based on the technical spirit provided by the present invention, and are therefore included in the scope of the present invention.

[0260] The present invention includes an electrochemical device comprising an electrode manufactured by the above-described manufacturing method.

[0261] The present invention includes a method for producing a composite separator using the coating solution.

[0262] The method for manufacturing a composite membrane according to the present invention comprises the step of applying the coating solution to a porous substrate. The porous substrate may comprise a porous membrane or a porous membrane and a porous coating layer located on one or both surfaces of the porous membrane. The porous substrate may be the same as or similar to the porous substrate in the aforementioned composite membrane. Therefore, the method for manufacturing a composite membrane may include all of the aforementioned aspects related to the porous substrate in the aforementioned composite membrane.

[0263] After the coating solution is applied, a step of applying energy to the coating solution may be performed. This may be for the purpose of accelerating or causing the curing of the curing component during drying and / or when the coating solution contains a curing component.

[0264] The coating method, specific coating amount, energy application, etc. of the coating solution are similar or identical to those described in the aforementioned electrode manufacturing method. Therefore, the manufacturing method of the composite diaphragm may include all of the above contents in the aforementioned electrode manufacturing method.

[0265] In the case where the coating solution does not contain a binder component, a coating layer of a metal salt in a form soluble in an electrolyte can be formed on the porous substrate.

[0266] When the coating solution contains a binding component, a coating layer of the metal salt fixed to the porous substrate can be formed.

[0267] When the coating solution contains a binding component and a particulate phase, a porous metal salt-containing coating layer containing a metal salt and having porosity due to gaps between particles of the particulate phase can be formed on the porous substrate.

[0268] The present invention includes an electrochemical device, which includes a composite membrane manufactured by the method for manufacturing the composite membrane.

[0269] The present invention includes a method for producing a separator using the above-mentioned coating solution.

[0270] The method for manufacturing a separator according to the present invention may include applying a coating solution on a porous membrane, wherein the fir coating solution comprises a metal salt according to a specific example of the above-mentioned coating solution; a particle phase; a binder, a curing component, or a binder and a curing component.

[0271] Therefore, a diaphragm can be manufactured in which a porous coating layer containing a metal salt is formed on at least one side (the side opposite to the electrode) or each of the two sides (the two sides opposite to the electrode) of the porous membrane, wherein the porous coating layer containing the metal salt has porosity due to the gaps between the particles of the granular phase, contains a metal salt and is bonded to the porous membrane.

[0272] After the coating solution is applied, energy may be applied to the coating solution to promote drying and / or, if the coating solution contains a curing component, to promote or cause curing of the curing component.

[0273] The porous membrane may be the same as or similar to the porous membrane in the aforementioned composite membrane. Therefore, the method for manufacturing the membrane may include all the above contents related to the porous membrane in the composite membrane.

[0274] The coating method, specific coating amount, energy application, etc. of the coating solution are similar or identical to those described in the aforementioned electrode manufacturing method. Therefore, the manufacturing method of the separator may include all of the above contents in the aforementioned electrode manufacturing method.

[0275] The present invention includes a method for producing an electrochemical device casing using the above-mentioned coating solution.

[0276] The method for manufacturing a housing according to the present invention includes applying the coating solution to the inner surface of the housing and, if necessary, applying energy to the coating solution. In this case, the inner surface of the housing coated with the coating solution may be the area that contacts the liquid electrolyte when assembled into an electrochemical device.

[0277] Depending on the specific composition of the coating solution, the metal salt located on the inner surface of the shell can be provided to the electrolyte, and at the same time or independently, the flame retardancy of the shell can be ensured by the metal salt remaining or fixed on the inner surface of the shell, or a smoother flow of active ions in the electrolyte can be induced.

[0278] The housing may be the same as or similar to the housing described in the aforementioned electrochemical device. Therefore, the method for manufacturing the housing may include all the above contents related to the housing in the aforementioned electrochemical device.

[0279] The coating method, specific coating amount, energy application, etc. of the coating solution are similar or identical to those described in the aforementioned electrode manufacturing method. Therefore, the manufacturing method of the housing may include all of the above contents in the aforementioned electrode manufacturing method.

[0280] The present invention includes a method for manufacturing an electrochemical device, wherein the method includes applying the coating solution to a component of the electrochemical device in contact with an electrolyte, and, if necessary, further including applying energy to the component coated with the coating solution (a coating of the coating solution). In this case, the component coated with the coating solution and obtained by applying energy, if necessary, is collectively referred to as a metal salt-containing component.

[0281] In the case where the structural component is an electrode, the method for manufacturing the electrochemical device may include the aforementioned method for manufacturing the electrode. Furthermore, in the case where the structural component is a diaphragm, the method for manufacturing the electrochemical device may include the aforementioned method for manufacturing the composite diaphragm or the method for manufacturing the diaphragm. In the case where the structural component is a housing, the method for manufacturing the electrochemical device may include the aforementioned method for manufacturing the housing. In the case where the structural component is two or more selected from an electrode, a diaphragm, and a housing, the method for manufacturing the electrochemical device may include all manufacturing methods for each of the above two or more structural components (including metal salt structural components).

[0282] According to a specific example, the manufacturing method of an electrochemical device may also include the steps of placing an electrode assembly with a separator between the positive electrode and the negative electrode and the electrolyte into a shell having an internal accommodating space and sealing the shell. At this time, one or more structural components selected from the positive electrode, the negative electrode, the separator and the shell can be a metal salt-containing structural component.

[0283] Taking the case where the structural component is a separator as an example, a method for manufacturing an electrochemical device according to one specific example may include: a) preparing a metal salt-containing separator (corresponding to a composite separator) by applying a coating solution to the separator (corresponding to a porous substrate); b) manufacturing an electrode assembly with the metal salt-containing separator positioned between a positive electrode and a negative electrode; and c) placing the electrode assembly and electrolyte into a housing having an internal storage space and sealing the housing. Furthermore, the method may include d) dissolving the metal salt contained in the metal salt-containing separator into the electrolyte within the sealed housing.

[0284] When the metal salt contained in the metal salt-containing diaphragm comes into contact with the liquid electrolyte, it can be dissolved in the electrolyte. Therefore, the concentration of the metal salt (corresponding to the salt of the active ion or the electrolyte salt) of the liquid electrolyte put into (injected) into the shell in step c) can be lower than the concentration of the metal salt in the electrolyte when the electrochemical device is used. At this time, it is obvious that the metal salt contained in the metal salt-containing diaphragm can be a salt of the active ion. And, in step a), the coating is performed in a manner such that the metal salt has a content that increases the concentration of the liquid electrolyte from the injection concentration to the designed concentration or a content above it. As a substantial example, the metal salt content can be such that the mass of the metal salt per unit area of ​​the diaphragm (corresponding to the porous substrate) is between 0.1 and 5.0 mg / cm 2 Apply in a horizontal manner.

[0285] In the case where flame retardancy or improved ion conductivity is to be imparted to the separator, the metal salt may be a sulfonyl group-containing metal salt, preferably, one or more metal salts selected from the compounds satisfying Chemical Formulas 1 to 4. When flame retardancy or improved ion conductivity is to be imparted to the separator, the metal salt content as the mass of the metal salt per unit area of ​​the separator (corresponding to the porous substrate) can be based on the metal salt dissolved in the electrolyte in step a) and remaining in the separator (corresponding to the porous substrate) or the metal salt that remains fixed to the separator (corresponding to the porous substrate) in a state of being 0.3 to 5.0 mg / cm 2 , 0.3 to 4.0 mg / cm 2 , 0.3 to 3.0 mg / cm 2 , 0.3 to 2.5 mg / cm 2 , 0.3 to 2.0 mg / cm 2 , 0.4 to 1.5 mg / cm 2 , 0.5 to 1.4 mg / cm 2 , or 0.5 to 1.2 mg / cm 2 At this time, it is obvious that the coating solution may contain a binding component, and the metal salt can also be coated on the separator (corresponding to the porous substrate) in a fixed state through this binding component.

[0286] The present invention may include an electrochemical device manufactured by the above-described manufacturing method.

[0287] Hereinafter, the present invention will be described in further detail based on Examples and Comparative Examples. However, the following Examples and Comparative Examples are merely examples for further illustrating the present invention, and the present invention is not limited to the following Examples and Comparative Examples.

[0288] 1) Ionic conductivity

[0289] The ionic conductivity of the separator can be confirmed by the following method.

[0290] (IC 隔膜 )

[0291] At this time, IC 隔膜 is the ionic conductivity of the separator when it is wetted by liquid electrolyte.

[0292] Regarding the above-mentioned ionic conductivity, after removing the separator wetted with the liquid electrolyte from the battery manufactured in the embodiment or comparative example, the separator was cut into a circle with a diameter of 18 mm and a button cell (2032) was manufactured. Alternatively, the separator cut into a circle with a diameter of 18 mm was injected with the same liquid electrolyte as in each embodiment or comparative example to wet the separator, and then a button cell (2032) was manufactured. Thereafter, the above-mentioned ionic conductivity was measured using an AC impedance measurement method based on temperature. The above-mentioned ionic conductivity was measured using a VMP3 measurement device in a frequency band of 1 MHz to 0.01 Hz.

[0293] The following details the Nyquist plot for measuring the ionic conductivity (IC) of a separator wetted with a liquid electrolyte. A separator wetted with a liquid electrolyte is an ionic conductor, and the Nyquist plot shows a vertically ascending pattern. The impedance resistance value on the horizontal axis represents the resistance related to ionic conduction. The resistance value related to ionic conduction obtained above can be calculated using the following formula.

[0294] [Calculation formula 1]

[0295] IC=L / (R 离子 ×A)

[0296] Here, L is the thickness of the test piece (thickness of the diaphragm), A is the area of ​​the test piece, and R 离子 =R2-R1, R1 is the resistance in the high-frequency region of the Nyquist diagram, and R2 is the resistance in the low-frequency region of the Nyquist diagram.

[0297] The ionic conductivity of the separator can be confirmed by the above method.

[0298] 2) Lithium ion transport coefficient (Li transport number)

[0299] To measure the lithium ion transport coefficient, a separator wetted with a liquid electrolyte was removed from a secondary battery manufactured in an embodiment or comparative example, cut into a circular shape with a diameter of 18 mm, and the separator was placed between two lithium foils with a diameter of 16 mm to manufacture a button cell (2032). Alternatively, a circular separator cut into a diameter of 18 mm was placed between two lithium foils with a diameter of 16 mm and wetted by injecting the same liquid electrolyte as in each embodiment or comparative example to manufacture a button cell (2032). The first impedance resistance value of the manufactured button cell was measured, and the current change was observed for 3600 seconds by applying a voltage of 10 mV, and the second impedance resistance value was measured.

[0300] Thereafter, the lithium ion transport coefficient (t Li + ).

[0301] [Calculation formula 2]

[0302] t Li + =(I s (ΔV-I 0 R 0 )) / (I 0 (ΔV-I s R s ))

[0303] At this time, I s refers to the steady-state current, ΔV refers to the applied voltage, I 0 Refers to the initial current (initial current), R 0 Rs refers to the initial resistance and Rs refers to the steady-state resistance.

[0304] 3) Analysis of the molar concentration and concentration gradient of electrolytes in battery materials

[0305] Experimentally, the concentrations of the metal salts in the electrodes and separators were measured according to the following method (1) and / or method (2) and by the following analytical method.

[0306] Method (1): 1) removing the seal of the electrochemical device (the secondary battery manufactured in the embodiment) and opening at least one end, cutting the connection between the electrode ear (tap) for electrical connection to the outside world and the electrode complex of the positive electrode-diaphragm-negative electrode, thereby separating and recovering the electrode complex; using a molding epoxy resin to cure the recovered electrode complex at a temperature of 60°C for more than 24 hours, and recovering the electrode complex molded in the epoxy resin; for a sample in which the molded electrode complex is cut into a cross-sectional specimen with a thickness of less than 20 μm using an ion beam, the sample is analyzed by neutron depth profiling, thereby directly confirming the concentration gradient of active metal ions in the cross section of the electrode complex.

[0307] Method (2): 1) removing the seal of the electrochemical device (the secondary battery manufactured in the embodiment) and opening at least one end, cutting off the connection between the electrode ear for electrical connection to the outside world and the positive electrode-diaphragm-negative electrode complex, thereby separating and recovering the electrode complex; 2) in the recovered electrode complex, analyzing the solution in which the diaphragm, positive electrode, and negative electrode were immersed in anhydrous deuterated dimethyl sulfoxide for 24 hours by the following method.

[0308] Analytical methods: One or more methods selected from fluorine nuclear magnetic resonance spectroscopy (F-NMR), chlorine nuclear magnetic resonance spectroscopy (Cl-NMR), inductively coupled plasma mass spectrometry (ICP-MS), proton nuclear magnetic resonance spectroscopy (H-NMR), and X-ray photoelectron spectroscopy (XPS) are used for analysis.

[0309] 4) Battery performance evaluation

[0310] For the secondary battery manufactured in the embodiment, the voltage range was 3.0-4.2 V and the current was 0.1 C (=0.3 mA / cm 2) current to observe the initial charge / discharge capacity. For the output characteristics (discharge characteristics by rate), the lithium battery was placed at room temperature (25℃) and charged at a current of 0.2C, and discharged at currents of 0.2C / 0.5C / 1.0C / 1.5C / 2.0C, respectively.

[0311] Output capacity retention (%) = [discharge capacity at a specific rate / initial 0.1C discharge capacity] × 100

[0312] The life characteristics of lithium batteries were observed according to the number of charge / discharge cycles at room temperature (25°C) and high temperature (45°C) with a current of 1.0C.

[0313] Cycle capacity retention rate (%) = [200th cycle discharge capacity / first cycle discharge capacity] × 100

[0314] 5) Porosity

[0315] The porosity (volume %) of the test pieces was measured using a mercury intrusion porosimetry instrument (AutoPore IV 9500, manufactured by Micromeritics Instrument Corp.). To eliminate the influence of pores formed by sample lamination, the porosity of the samples was calculated under pressures ranging from 30 psia to 60,000 psia.

[0316] 6) Liquid electrolyte wettability evaluation

[0317] 20 μl of a liquid electrolyte prepared by dissolving LiPF6 at a concentration of 1 M in a mixed solvent of ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1 was used as a reference electrolyte. This was dropped onto the separators of the examples and comparative examples and the wettability changes after 60 seconds were observed.

[0318] 7) Flame retardancy evaluation

[0319] After immersing in the following reference electrolyte for 1 minute, the separator was recovered. When the gravity direction was parallel to the in-plane direction of the separator after recovery, the following flame retardancy test was performed at the point when no droplets fell to the bottom within 1 minute.

[0320] Reference electrolyte: a mixed solvent of ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1, a lithium salt of LiPF6, a LiPF6 concentration of 1 M, and a temperature of 25°C ± 5°C.

[0321] Flame retardancy test: The length of the flame in the atmosphere is 5 to 10 cm, the temperature of the flame tip is 1000 to 1500°C, the length of the flame area not in contact with the diaphragm when the flame is applied to the diaphragm is 50 to 80% of the length of the flame in the atmosphere, and the movement speed of the flame in contact with the diaphragm is 1 to 5 cm / sec.

[0322] exist Figures 1 to 8 The evaluation results of the separators manufactured by the examples and comparative examples according to the flame retardancy evaluation method are shown in FIG. Figures 1 to 7 As shown, all the membranes manufactured and evaluated by the examples did not generate flames during the flame retardancy test, but Figure 8 As shown, in the case of the separator prepared in the comparative example, it was confirmed that flames were generated during the flame retardancy test.

[0323] 8) Scanning electron microscopy and energy dispersive composition analysis

[0324] Scanning electron microscopy and energy dispersive compositional analysis (Field Emission Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (FE-SEM, EDS, S-4800, Hitachi)) were performed on the surface and cross-section samples of the composite separator, as well as the surface and cross-section samples of the positive and negative electrodes opposite the composite separator. The surface and cross-section morphology and compositional analysis confirmed the detectability of the elements derived from the metal salts in the samples and their differences in content.

[0325] 9) X-ray diffraction analysis

[0326] The composite membranes produced in the examples were cut into appropriate sizes and subjected to high-resolution X-ray diffractometer (HRXRD) analysis (SmartLab, RIGAKU, Cu Kα beam). X-ray diffraction analysis of the metal salt-coated composite membranes confirmed whether the metal salt coated on the membrane was crystallized and whether it was dissociated.

[0327] exist Figure 9The results of the evaluation of the crystallization state of the metal salts of the separators prepared by the examples and comparative examples are shown in FIG. In the separator prepared and evaluated by Example 7, a diffraction peak (2theta = 33.3°) corresponding to the undissociated crystalline state of the lithium bis(trifluoromethanesulfonyl)imide metal salt was observed. However, in the separator coated with the composite electrolyte prepared by Comparative Example 3, no diffraction peak having a crystalline phase was observed due to the dissociated state of the metal salt.

[0328] 10) Adhesion analysis

[0329] The separator samples produced in Examples and Comparative Examples were attached to a slide glass, and the adhesive strength was evaluated using a universal testing machine (equipment name: DA-01, equipment manufacturer: Petrol LAB).

[0330] exist Figure 10 The results of the adhesion evaluation of the separators produced in Examples and Comparative Examples are shown in Figure 2. The separator produced and evaluated in Example 7 was in a completely dry state, and no adhesion was measured. However, the separator produced and evaluated in Comparative Example 3 had a sticky surface due to the liquid phase components and dissociated metal salts present in the composite electrolyte coating layer. This indicates that it has high adhesion and is not suitable for processes such as rolling.

[0331] 11) Mass change measurement

[0332] The weight change of the composite separator was measured with time at a temperature of 25°C in the atmosphere immediately after manufacture. Figure 11 The following table shows the results of the evaluation of the weight change over time for the separators produced in Examples and Comparative Examples. Due to the absence of liquid phase components, the weight of the separator produced and evaluated in Example 7 did not change over time. However, due to the influence of the volatilization of the liquid phase components present in the composite electrolyte coating layer, the weight of the separator produced and evaluated in Comparative Example 3 was observed to change over time.

[0333] 12) Infrared spectroscopy

[0334] The composite separator, the positive electrode, and the negative electrode facing the composite separator were separated from the electrode assembly after the initial formation process was completed by applying a charge and discharge current. Fourier transform infrared spectroscopy (Fourier transform infrared spectroscopy, instrument name: 670-IR, equipment manufacturer: Varian) was performed on each. It was confirmed that the absorption spectrum obtained by dispersing the reflected light when irradiated with infrared rays can distinguish the peak intensity that determines the material characteristics of the elemental components derived from the metal salt in the source sample.

[0335] 13) X-ray photoelectron analysis

[0336] The composite separator, the positive electrode, and the negative electrode facing the composite separator were separated from the electrode assembly after the initial formation process was completed by applying a charge and discharge current. X-ray photoelectron spectroscopy (K-Alpha, ThermoFisher) was performed on each. It was confirmed that the energy of the photoelectrons that escape when the sample is irradiated with X-rays can be used to distinguish and determine the presence of elements derived from metal salts in the sample and the state of chemical bonds.

[0337] 14) Inductively coupled plasma mass analysis

[0338] The composite membrane, the positive electrode, and the negative electrode facing the composite membrane were separated from the electrode assembly after the initial formation process was completed by applying a charge and discharge current. Inductively Coupled Plasma Mass Spectrometry (ELAN DRC-II, Perkin Elmer) was performed on each. This confirmed that by ionizing the elemental components derived from the metal salt contained in the sample and separating these ions using a mass analyzer, the presence and content of the elemental components derived from the metal salt in the sample can be distinguished and determined.

[0339] 15) Nuclear magnetic resonance spectroscopy

[0340] The composite separator, the positive electrode, and the negative electrode facing the composite separator were separated from the electrode assembly in a state where the initial formation process had been completed by applying charge and discharge currents, and two-dimensional nuclear magnetic resonance spectroscopy (NMR) was performed on each (Avance III HD, Bruker). This confirmed that by utilizing the nuclear magnetic resonance phenomenon of atomic nuclei generated when a magnetic field is applied to elemental components derived from metal salts contained in the sample, information about the chemical environment surrounding the nuclei and spin coupling with neighboring atoms can be obtained, thereby distinguishing and determining the presence and concentration of elemental components derived from metal salts in the sample.

[0341] 16) Time-of-flight secondary ion mass spectrometry

[0342] The composite separator, the positive electrode, and the negative electrode facing the composite separator were separated from the electrode assembly after the initial formation process was completed by applying a charge and discharge current. Time-of-flight Secondary Ion Mass Spectrometry (TOF-SIMS5, ION TOF) was performed on each. It was confirmed that the presence and concentration of elemental components derived from metal salts in the sample can be distinguished and determined by mass analysis of secondary ions generated in the sample.

[0343] 17) Measurement of dissolution rate of composite membrane

[0344] The mass (W) of the composite membrane manufactured in the embodiment was measured. 干 ), the composite membrane was completely immersed in a 25°C reference electrolyte (a solution in which LiPF6 was dissolved in a mixed solvent of ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1 at a concentration of 1M) for 1 hour, and then the composite membrane was recovered. The mass (W) of the dried composite membrane was measured after drying at 80°C for 12 hours. 湿 ), using the mass of each composite membrane measured and the total mass of the metal salt contained in the composite membrane in the just-prepared state (W m ), through (W 湿 -W 干 ) / W m The dissolution rate (metal salt dissolution rate) was calculated by the formula of ×100(%). In order to reduce the measurement error, 20 diaphragms were treated in the same way and the W of all 20 diaphragms was measured. 干 and W 湿 The dissolution rate was calculated.

[0345] [Example 1]

[0346] 1) Manufacturing of composite diaphragms containing metal salts

[0347] Lithium perchlorate was used as the metal salt, and dimethyl carbonate was used as the coating solvent. 20 wt % of lithium perchlorate was added to dimethyl carbonate, and the mixture was stirred at room temperature for 1 hour to prepare a coating solution containing the metal salt.

[0348] A coated separator with a ceramic coating layer (17 μm total thickness, 15 μm thick polyethylene, 1 μm thick ceramic coating layer on each side) was used as the porous substrate. A coating solution containing a metal salt was applied to one side of the porous substrate using a doctor blade. The solution was dried at 60°C for 1 hour to evaporate the coating solvent, thereby producing a composite separator containing a metal salt. Table 1 summarizes the metal salt content of the coating solution on one side of the porous substrate.

[0349] The dissolution rate test results of the manufactured composite membrane confirmed that the metal salt dissolution rate reached 65%.

[0350] 2) Manufacturing of lithium-ion secondary batteries

[0351] Positive electrode production: Based on 100% by weight of solid content, 96% by weight of lithium-nickel-manganese-cobalt composite oxide (LiNi 0.6 Co 0.2 Mn 0.2 A positive electrode active material composition (positive electrode mixture slurry) was prepared by adding N-methyl-2-pyrrolidone (as an organic solvent) to a solid content of 50 wt % of solid O2) (as a positive electrode active material), 2 wt % of Super-P with an average particle size of 40 nm (as a conductive material), and 2 wt % of polyvinylidene fluoride (as a binder).

[0352] The positive electrode active material composition was applied to a 20 μm thick aluminum film using a doctor blade, dried at 120°C, and then rolled using a roll press to prepare a 50 μm thick positive electrode coated with an active material layer. The porosity was 15% by volume.

[0353] Negative electrode production: A negative electrode active material composition (negative electrode mixture slurry) was prepared by adding solid components to water. The solid components were 96% by weight of natural graphite powder (as a negative electrode active material), 2% by weight of carbon black with an average particle size of 40 nm (as a conductive material), 1% by weight of styrene-butadiene rubber (rubber) (as a binder), and 1% by weight of carboxymethyl cellulose, based on 100% by weight of solid components. The negative electrode active material composition was applied to a 20 μm thick aluminum film using a doctor blade, dried at 120°C, and then rolled by a roller press to prepare a 65 μm thick negative electrode coated with an active material layer. The porosity was 20% by volume.

[0354] Secondary battery manufacturing: The electrode assembly is manufactured by stacking the manufactured positive electrode, negative electrode and composite separator containing metal salt. After sealing the battery case, the battery (button cell and soft pack cell) is manufactured by injecting a liquid electrolyte containing LiPF6 dissolved at a concentration of 1M in a mixed solvent of ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1.

[0355] To evaluate the physical properties of the manufactured batteries, the batteries, after the initial formation process had been completed by applying charge and discharge currents, were disassembled. The composite separator, the positive electrode, and the negative electrode facing the composite separator were separated from the electrode assembly, and the physical properties were measured and shown in Table 1. The electrolyte concentrations in the composite separator, positive electrode, and negative electrode were analyzed using nuclear magnetic resonance spectroscopy. The measured concentrations were verified by additionally preparing electrolytes corresponding to the measured concentrations to confirm whether the analysis results were the same.

[0356] [Example 2]

[0357] Batteries (button cells and soft-pack batteries) were manufactured in the same manner as in Example 1, except that a composite separator was manufactured by using a porous film (polyethylene with a thickness of 9 μm) without introducing a ceramic coating layer as the porous substrate of the composite separator containing a metal salt in the above Example 1.

[0358] [Example 3]

[0359] Batteries (a button cell and a pouch cell) were manufactured in the same manner as in Example 1, except that lithium trifluoromethanesulfonate was used as the metal salt to manufacture the composite separator.

[0360] The physical properties of the manufactured batteries are measured and shown in Table 1. The flame retardancy evaluation results are shown in Figure 1 .like Figure 1 As shown, even when only a crystalline metal salt containing a sulfonyl group was formed on the porous substrate, no flame was generated during the flame retardancy test.

[0361] The dissolution rate test results of the manufactured composite membrane confirmed that the dissolution rate of the metal salt reached 80%.

[0362] [Example 4]

[0363] Batteries (button cells and soft-pack batteries) were manufactured in the same manner as in Example 3, except that a composite separator was manufactured by using a porous film (polyethylene with a thickness of 9 μm) without introducing a ceramic coating layer as the porous substrate of the composite separator containing a metal salt in the above Example 3.

[0364] The physical properties of the manufactured batteries are measured and shown in Table 1. The flame retardancy evaluation results are shown in Figure 2 .like Figure 2As shown, when the polyethylene porous substrate having no ceramic coating layer was coated only with the crystalline metal salt containing a sulfonyl group, no flame occurred during the flame retardancy test.

[0365] [Example 5]

[0366] In addition to the coating solution containing the metal salt in Example 1, a coating solution was prepared by adding 20 wt% of lithium trifluoromethanesulfonate, 3.5 wt% of ethoxylated trimethylolpropane triacrylate, and 0.35 wt% of hydroxymethylphenylacetone (as a photoinitiator) to dimethyl carbonate. The solution was then applied at 2000 mW / cm 2 A composite separator was produced in the same manner as in Example 1, except that the film was irradiated with ultraviolet rays for 20 seconds for cross-linking, and batteries (a button cell and a pouch cell) were produced.

[0367] The physical properties of the manufactured batteries are measured and shown in Table 1. The flame retardancy evaluation results are shown in Figure 3 .like Figure 3 As shown, when the crystalline metal salt containing a sulfonyl group is bonded to a porous substrate through an adhesive component, no flame is generated in the flame retardancy test.

[0368] [Example 6]

[0369] Batteries (button cells and soft-pack batteries) were manufactured in the same manner as in Example 5, except that a composite membrane was manufactured by using a porous membrane (polyethylene with a thickness of 9 μm) without introducing a ceramic coating layer as the porous substrate of the composite membrane containing metal salt in the above Example 5.

[0370] The physical properties of the manufactured batteries are measured and shown in Table 1. The flame retardancy evaluation results are shown in Figure 4 .like Figure 4 As shown, when the crystalline metal salt containing a sulfonyl group is bonded to a polyethylene porous substrate having no porous inorganic layer via a bonding component, no flame is generated in the flame retardancy test.

[0371] [Example 7]

[0372] A coating solution containing a metal salt was prepared, consisting of 6.65 wt% silicon dioxide (SiO2), 0.35 wt% polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), 20 wt% lithium bis(trifluoromethanesulfonyl)imide, and the balance acetone. The polymer, PVDF-HFP, was first dissolved in acetone, and the remaining components were then added to the solution in appropriate proportions.

[0373] Batteries (button cells and soft-pack cells) were manufactured in the same manner as in Example 1, except that a porous film (polyethylene with a thickness of 9 μm) without an introduced ceramic coating layer was used as a porous substrate for a composite separator containing a metal salt, and a ceramic coating layer containing a metal salt was formed on both sides of the porous substrate using the prepared coating solution and dip coating to manufacture a composite separator with a thickness of 13 μm.

[0374] The physical properties of the manufactured batteries are measured and shown in Table 1. The flame retardancy evaluation results are shown in Figure 5 .like Figure 5 As shown in FIG, when a ceramic coating layer is formed on a polyethylene porous film and a crystalline metal salt containing a sulfonyl group is bonded to the ceramic coating layer through a bonding component, no flame occurs in the flame retardancy test. Figure 9 The X-ray diffraction pattern results for evaluating the crystalline characteristics of the prepared membrane are shown in Figure 10 The results of evaluating the adhesive properties are shown in Figure 11 The results of the evaluation of the volatility characteristics are shown in FIG.

[0375] [Example 8]

[0376] After manufacturing the electrode assembly in the same manner as in Example 7 and sealing it in the battery case, batteries (button cells and soft-pack batteries) were manufactured in the same manner as in Example 7, except that a liquid electrolyte in which LiPF6 was dissolved at a concentration of 1 M in a solvent of 1,2-dimethoxyethane (DME) and 1,3-dioxolane (DOL) mixed in a volume ratio of 1:1 was injected.

[0377] The physical properties of the manufactured batteries are measured and shown in Table 1. The flame retardancy evaluation results are shown in Figure 6 .like Figure 6 As shown, in the battery, even if the solvent of the electrolyte in contact with the manufactured composite separator changes, no flame occurs, which shows that flame retardancy can be ensured regardless of the specific type of solvent.

[0378] [Example 9]

[0379] The battery in the following state is decomposed: the soft pack battery prepared by the above Example 7 is in the voltage range of 3.0 to 4.2 V and is charged at 0.1 C (=0.3 mA / cm 2 After formation (formation) under the current condition of 2 times, the battery completed 100 charge / discharge cycles at a current of 1.0C. After disassembly, the composite separator, the positive electrode and the negative electrode opposite to the composite separator were separated from the electrode assembly and their physical properties were measured. The results are summarized in Table 1 and are Figure 7The results of the flame retardancy evaluation are shown in FIG. Figure 7 As shown, the battery provided with the manufactured composite separator was repeatedly charged and discharged, and no flame occurred during the flame retardancy test. This shows that flame retardancy can be ensured regardless of whether the battery is used or to what extent it is used.

[0380] [Comparative Example 1]

[0381] In the above-mentioned Example 1, except for using a separator that does not contain metal salt (total thickness of 17 μm, raw material thickness of polyethylene of 15 μm, and ceramic coating layer of 1 μm on both sides), batteries (button cells and soft-pack cells) were manufactured in the same manner as in Example 1.

[0382] The physical properties of the manufactured batteries are measured and shown in Table 1. The flame retardancy evaluation results are shown in Figure 8 , the crystallization characteristics evaluation results are shown in Figure 9 .like Figure 8 As shown, no flame occurred during the flame retardancy evaluation.

[0383] [Comparative Example 2]

[0384] Batteries (a button cell and a pouch cell) were manufactured in the same manner as in Comparative Example 1, except that a liquid electrolyte containing 2.5 M LiPF 6 was injected instead of a liquid electrolyte containing 1 mol of LiPF 6.

[0385] The physical properties of the manufactured batteries were measured and shown in Table 1.

[0386] [Comparative Example 3]

[0387] After dissolving polyethylene oxide (PEO) at 2% by weight in acetonitrile, an ionic liquid (LI) was added. The IL was a 1.5M electrolyte solution of lithium bis(trifluoromethanesulfonyl)imide (1-methyl-1-propylpyrrolidinium bis(fluorosulfonyl)imide, PYR13FSI). The composite electrolyte composition contained 80 parts by weight of ionic liquid and 20 parts by weight of PEO, based on 100 parts by weight of the combined ionic liquid and PEO.

[0388] Batteries (button cells and soft pack batteries) were manufactured in the same manner as in Example 1, except that the composite electrolyte composition was dip-coated on both sides of the porous substrate with a thickness of 5 μm in a porous membrane (9 μm polyethylene) and dried at 60°C for 1 hour to produce a composite separator.

[0389] The physical properties of the manufactured batteries are measured and shown in Table 1. The crystallization characteristics of the prepared separators are evaluated in Table 1. Figure 9 , the results of the adhesive properties evaluation are shown in Figure 10 , the results of the volatility characteristics evaluation are shown in Figure 11 .

[0390] (Table 1)

[0391]

[0392] From the X-ray diffraction measurement results showing the crystallinity evaluation Figure 9 (As a reference, the X-ray diffraction pattern of LiTFSI powder as the metal salt used in manufacturing the composite separator is shown at the bottom.) It can be seen that the composite separator manufactured in Example 7 may contain a crystalline metal salt. Moreover, although not shown in the figure, all the composite separators prepared in the examples contain the same crystalline metal salt as in Example 7. When a separator containing a sulfonyl metal salt containing such a crystalline phase is provided in a battery, as Figures 1 to 7 As shown in Table 1, it can be confirmed that excellent flame retardancy is ensured. Also, as shown in Table 1, when the composite separator contains a metal salt in a crystalline phase, both the ion conductivity and the lithium ion transport coefficient increase.

[0393] As described above, the present invention is described through specific matters and limited embodiments and drawings, but these are provided only to help further understand the present invention as a whole. The present invention is not limited to the above embodiments, and ordinary technicians in the field to which the present invention belongs can make various modifications and changes based on these descriptions.

[0394] Therefore, the gist of the present invention should not be limited to the described embodiments, and the aforementioned claims and modifications equivalent to or equivalent to the claims are all within the scope of the gist of the present invention.

Claims

1. A composite diaphragm for an electrochemical device, characterized in that: comprising a porous substrate and a crystalline metal salt containing a sulfonyl group, The metal ions participating in the electrochemical reaction of the electrochemical device provided with the composite separator are used as active ions, and the metal ions of the metal salt include active ions. The composite diaphragm for an electrochemical device satisfies the following formula 1: [Formula 1] 5(%)≤(W 干 -IN 湿 ) / IN m ×100(%) In formula 1, W 干 is the mass of the composite diaphragm before contacting with the electrolyte, W 湿 W is the mass of the composite diaphragm recovered and dried after immersing the composite diaphragm in a reference electrolyte at a temperature of 25°C for 1 hour, wherein the reference electrolyte is an electrolyte in which LiPF6 is dissolved at a concentration of 1 M in a mixed solvent of ethylene carbonate and dimethyl carbonate mixed in a volume ratio of 1:1, m is the mass of metal salt contained in the composite diaphragm before it comes into contact with the electrolyte, When the X-ray diffraction analysis using Cu Kα line is performed, it has at least one diffraction peak of the crystalline metal salt, After immersion in the following reference electrolyte for 1 minute, the membrane is recovered and placed in a manner such that the in-plane direction of the membrane is parallel to the direction of gravity. When the following flame retardancy test is performed at a time point when no droplets fall from the membrane to the bottom within 1 minute, no flame occurs on the membrane. Benchmark electrolyte: a mixed solvent of ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1, a lithium salt of LiPF6, a LiPF6 concentration of 1M, a temperature of 25℃±5℃, Flame retardancy test: The length of the flame in the atmosphere is 5 cm to 10 cm, the flame tip temperature is 1000°C to 1500°C, the length of the flame area that is not in contact with the diaphragm when the flame is applied to the diaphragm is 50% to 80% of the length of the flame in the atmosphere, and the flame movement speed in contact with the diaphragm is 1 cm / sec to 5 cm / sec.

2. The composite diaphragm for an electrochemical device according to claim 1, characterized in that: The porous substrate includes a porous membrane, and the metal salt is located on a surface of the porous membrane.

3. The composite diaphragm for an electrochemical device according to claim 1, characterized in that: The porous substrate comprises: porous membrane; and A porous coating layer is located on at least one side of the porous membrane. The metal salt is located in one or more regions selected from the interface between the porous membrane and the porous coating layer, the interior of the porous coating layer, and the surface region of the porous coating layer.

4. The composite diaphragm for an electrochemical device according to claim 3, characterized in that: The porous coating layer comprises inorganic particles, organic particles, organic-inorganic composite particles or mixed particles thereof.

5. The composite diaphragm for electrochemical devices according to claim 1, characterized in that: The sulfonyl group-containing metal salt is one or more compounds selected from the group consisting of compounds satisfying the following chemical formulas 1 to 4: [Chemical formula 1] In chemical formula 1, A + is a monovalent cation, R1 is F, CFH2, CF2H or C n F 2n+1 , where n is a natural number greater than 1, [Chemical formula 2] In chemical formula 2, A 2+ is a divalent cation, R1 is F, CFH2, CF2H or C n F 2n+1 , where n is a natural number greater than 1, [Chemical formula 3] In chemical formula 3, A + is a monovalent cation, R1 and R2 are each independently F, CFH2, CF2H or C n F 2n+1 , where n is a natural number greater than 1, [Chemical formula 4] In chemical formula 4, A 2+ is a divalent cation, R1 and R2 are each independently F, CFH2, CF2H or C n F 2n+1 , where n is a natural number greater than 1.

6. The composite diaphragm for electrochemical devices according to claim 1, characterized in that: The composite separator is a salt supply source for providing the metal salt to an electrolyte of an electrochemical device.

7. The composite separator for an electrochemical device according to any one of claims 1 to 5, characterized in that: The metal salt is fixed by one or more adhesive components selected from linear polymers and cross-linked polymers.

8. The composite diaphragm for an electrochemical device according to claim 7, characterized in that: The fixing is achieved by curing the curing component in a state of being mixed with the metal salt, wherein the curing component is converted into an adhesive component by curing and has curability.

9. The composite diaphragm for an electrochemical device according to claim 1, characterized in that: The composite separator includes a coating layer located on one side of the porous substrate and containing the metal salt.

10. The composite separator for an electrochemical device according to claim 1, characterized in that: The porous substrate comprises: porous membrane; and A porous coating layer is located on at least one side of the porous membrane. The composite separator includes a coating layer located between the porous membrane and the porous coating layer, in a surface region of the porous coating layer, or between the porous membrane and the porous coating layer and in a surface region of the porous coating layer and containing the metal salt.

11. The composite separator for an electrochemical device according to claim 9 or 10, characterized in that: The coating layer including the metal salt further includes at least one polymer selected from linear polymers and cross-linked polymers.

12. The composite separator for an electrochemical device according to any one of claims 1 to 6 and 9 and 10, characterized in that: The metal salt content as the mass of the metal salt per unit area of ​​the porous substrate is 0.1 mg / cm 2 Up to 5.0mg / cm 2 .

13. An electrochemical device, characterized in that: It comprises a composite diaphragm for an electrochemical device according to any one of claims 1 to 6 and 9 and 10.

14. The electrochemical device according to claim 13, characterized in that The metal ions participating in the electrochemical reaction of the electrochemical device are used as active ions, and the molar concentration of the salt of the active ions contained in the electrolyte is 0.5M to 6.0M.

15. An electrochemical module, characterized in that: Two or more electrochemical devices according to claim 13 are electrically connected.

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