KR101310577B1 - Structure for electrochemical device to improve safety and electrochemical device comprising the same - Google Patents

Abstract

The present invention is a hollow cylindrical tube; A first member made of a polymer and sealing one end of the hollow cylindrical tube; And a second member made of a polymer or a metal and sealing the other end of the hollow tubular tube, wherein the interior empty space includes an ionic salt.

In addition, the present invention is a tube of two or more hollow cylindrical tube connected up and down by a polymer; A third member sealing one end of the pipe connected vertically; And a fourth member for sealing the other end of the tube connected vertically, wherein the internal empty space includes an ionic salt.

In addition, the present invention has a hollow cylindrical tube having at least one opening on the surface, the both ends are sealed; And a structure comprising a polymer member for sealing the opening, and relates to a structure for an electrochemical device characterized in that it comprises an ionic salt in the inner empty space.

The present invention also relates to an electrochemical device including an anode, a cathode, a separator, an electrolyte solution, a device case, and a structure for an electrochemical device.

Electrochemical Device, Secondary Battery, Structure, Center Pin, High Temperature, Overcharge, Safety

Description

Structure for electrochemical device for improving safety and electrochemical device including same {STRUCTURE FOR ELECTROCHEMICAL DEVICE TO IMPROVE SAFETY AND ELECTROCHEMICAL DEVICE COMPRISING THE SAME}

1 to 7 are each a plan view showing an example of the structure for an electrochemical device according to the present invention.

The present invention relates to a structure for an electrochemical device including an ionic salt therein that can provide safety even when the temperature or voltage of the device is abnormally raised, and an electrochemical device including the structure.

Recently, miniaturization and lighter weight of electronic equipment have been realized and use of portable electronic devices has become common, so researches on lithium secondary batteries having high energy density have been actively conducted.

A lithium secondary battery is prepared by using a material capable of inserting and detaching lithium ions as a cathode and an anode, and filling an organic electrolyte or a polymer electrolyte between the anode and the cathode. Electrical energy is generated by oxidation and reduction reactions when inserted and detached from the cathode.

However, such lithium secondary batteries have safety problems such as ignition and explosion due to the use of nonaqueous electrolyte, and these problems become more serious as the capacity density of the battery increases. Specifically, when the battery is overcharged and the normal operating voltage is exceeded, the positive electrode emits excessive lithium, and the excess lithium generates dendrites on the negative electrode, so that both the positive electrode and the negative electrode are thermally unstable, and thus the electrolyte is released. Rapid exothermic reactions occur such as decomposition. Such exothermic reactions cause ignition and rupture of the battery due to thermal runaway, which is a problem for the safety of the battery.

Many solutions have been proposed to control overcharging, explosion, or explosion due to temperature increase in the battery as described above. As an example, a method using a nonaqueous electrolyte additive is known. However, in order to improve safety by using the nonaqueous electrolyte additive, a large amount of additives should be added, but when directly added to the nonaqueous electrolyte, there is a problem in that the performance of the battery is reduced.

Accordingly, there is a need for the development of new methods for improving the safety of electrochemical devices such as batteries.

The present invention has an empty space therein, the empty space may include a material that can improve the safety of the device, the structure for an electrochemical device that can easily adjust the amount of the material contained in the empty space It aims to provide.

In addition, when the temperature inside the device including the structure of the present invention becomes abnormally high temperature or in the state of overvoltage by overcharging, the ionic salt, which is a material contained in the internal empty space of the structure, is released to the outside of the structure It is an object of the present invention to provide an electrochemical device structure capable of improving the safety of the device by the electrochemical reaction of the released ionic salt.

In addition, an object of the present invention is to provide an electrochemical device comprising the electrochemical device structure.

The present invention is a hollow cylindrical tube; A first member made of a polymer and sealing one end of the hollow cylindrical tube; And a second member made of a polymer or metal and sealing the other end of the hollow cylindrical tube.

The internal empty space provides a structure for an electrochemical device, characterized in that it comprises an ionic salt.

In addition, the present invention is a tube of two or more hollow cylindrical tube connected up and down by a polymer; A third member sealing one end of the pipe connected vertically; And a fourth member sealing the other end of the pipe connected vertically,

The internal empty space provides a structure for an electrochemical device, characterized in that it comprises an ionic salt.

In addition, the present invention has a hollow cylindrical tube having at least one opening on the surface, the both ends are sealed; And a structure comprising a polymer member for sealing the opening,

An internal empty space provides a structure for an electrochemical device, which comprises an ionic salt.

The present invention also provides an electrochemical device including an anode, a cathode, a separator, an electrolyte, a device case, and a structure for the electrochemical device.

Hereinafter, the present invention will be described in detail.

The electrochemical device structure according to the present invention is a sealed structure having an empty space therein, and an ionic salt, which is a substance capable of improving the safety of the electrochemical device using the structure of the present invention, into an internal empty space. It can include, and can easily adjust the amount of the material contained in the empty space.

Further, the structure according to the present invention does not affect the device when the temperature and voltage inside the device including the same are normal, but when the temperature inside the device becomes abnormally high temperature or overvoltage due to overcharge, A portion of the polymer component of the structure may be melted. As such, when a certain portion of the structure for an electrochemical device according to the present invention is melted, the inside of the structure is opened to the outside, wherein the ionic salt contained in the empty space inside the structure may be released to the outside of the structure. .

The cations and anions of the ionic salts released to the outside of the structure may move to the anode and the cathode included in the device, respectively, so that a reduction reaction and an oxidation reaction may occur. Specifically, the cation of the ionic salt in the cathode reacts with the highly integrated electrons due to a short circuit or an overcharge state due to external shock or internal causes to reduce the number of electrons, thereby suppressing a rise in temperature due to rapid current flow. Can be. In addition, the anion of the ionic salt in the anode generates a non-combustible gas to make the interior of the device in a non-combustible atmosphere can improve the safety of the device.

For example, when the ionic salt is NaCl, Na ⁺ of NaCl released to the outside of the structure moves to the cathode and consumes electrons, is reduced to precipitate as metal (Na), and Cl ⁻ is moved and oxidized to the anode. As a result of the generation of incombustible Cl ₂ gas, the safety of the device can be improved.

In addition, a pressure sensitive device such as a CID is provided inside the device including the structure for an electrochemical device of the present invention to stop the charging of the device or change the charging state to the discharge state by detecting a pressure change, or If a pressure release valve, such as a vent, is provided to dissipate heat or gas inside the device through change detection, the pressure sensitive device is caused by a gas generated by an electrochemical reaction of an ionic salt released to the outside of the structure. The pressure release valve is operated, whereby the safety of the device can be improved.

The material included in the inner empty space of the structure for an electrochemical device according to the present invention is an ionic salt, a material in which a metal is precipitated by an electrochemical reaction and gas may be generated. In addition, it is preferable that the cation of the ionic salt reacting with the electron is a substance having as much polyvalent positive charge as possible.

Non-limiting examples of the ionic salts include Al ₂ (SO ₄ ) ₃ , Ca (OH) ₂ , Mg (NO ₃ ) ₂ , PbI ₂ , NaCl, MgCl _2, Al ₂ (OH) ₃ , but are not limited thereto. I never do that. In addition, these ionic salts can be used individually or in mixture of 2 or more types. In addition, the amount of the ionic salt is not particularly limited and may be appropriately adjusted according to the volume of the empty space inside the case.

 In addition, the inner empty space of the structure for an electrochemical device according to the present invention may further include a material for dissolving the ionic salt. The ionic salt may be present in a dissolved state if a substance that dissolves the ionic salt is included, so that when the ionic salt is released out of the structure, the cations and anions of the ionic salt are faster to the cathode and the anode, respectively. By moving the electrochemical reaction it can contribute more to the safety of the device.

Non-limiting examples of the material for dissolving the ionic salts include, but are not limited to, water, alcohol, acetonitrile, carbonate and the like. These may be used alone or in combination of two or more. In addition, the amount of these used is not particularly limited, but an amount less than or equal to the amount of the ionic salt dissolved in the saturated solution is preferable.

The structure for an electrochemical device according to the present invention can be classified into three types.

Electrochemical device structure of the first aspect according to the present invention is a hollow cylindrical tube; A first member made of a polymer and sealing one end of the hollow cylindrical tube; And a second member made of a polymer or a metal and sealing the other end of the hollow cylindrical tube, wherein the vacant interior of the structure includes an ionic salt.

The electrochemical device structure of the first aspect is characterized in that the first member, or both the first member and the second member is melted at a temperature higher than the normal operating temperature of the device using the same or a voltage of 4.3V or more. At this time, the temperature higher than the normal operating temperature of the device is preferably 70 ~ 200 ℃.

As such, when both of the first member, or the first member and the second member are melted in the electrochemical device structure of the first aspect of the present invention, the inside of the structure may be opened to the outside.

The polymer forming the first member and the second member is not particularly limited as long as it can be melted at a temperature higher than the normal operating temperature of the device using the electrochemical device structure or at a voltage of 4.3 V or more. Non-limiting examples thereof include silicone resin, acrylic resin, urethane resin, epoxy resin, rubber, polyethylene, polypropylene, polybutene, polyacetaldehyde, polyformaldehyde, polypropylene oxide, polymethyl methacrylate, polyvinylidene chloride , Polyvinyl fluoride, polyvinylidene fluoride and the like, and these may be used alone or in combination of two or more thereof. The polymer forming the first member and the polymer forming the second member may be the same or different components.

In addition, the hollow cylindrical tube may be made of a polymer or a metal. At this time, the hollow tubular tube forms the skeleton of the electrochemical device structure according to the present invention is preferably durable, electrochemical safety, thermal stability.

The polymer forming the hollow cylindrical tube may be the same or different components as the polymer constituting the first member and the second member, but preferably, the polymer constituting the first member and the second member. Polymers having a melting point higher than the melting point, more preferably those which can be maintained in their original form without melting at a temperature higher than the normal operating temperature of the device using the structure or at a voltage of 4.3 V or higher. Non-limiting examples thereof include ethylene vinyl acetate (EVA), polystyrene, polyphenylene ether (PPE), polychlorotrifluoroethylene, polyvinyl chlorite (PVC), polyethylene terephthalate (PET), polyamide, polycapro Lactam, polycarbonate (PC), poly- (p-xylene), polyimide (PI), polyoxybenzoate (POB), polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polyether sulfone (PES), polysulfone (PSU), silicone resin, acrylic resin, urethane resin, epoxy resin, rubber, polyethylene, polypropylene, polybutene, polyacetaldehyde, polyformaldehyde, polypropylene oxide, polymethyl methacrylate, Polyvinylidene chloride, polyvinylidene fluoride, polyvinylidene fluoride, and the like, and these may be used alone or in combination of two or more thereof.

In addition, the metal forming the hollow tubular tube and the second member has a melting point higher than the melting point of the polymer constituting the first member and the second member, and preferably is higher than the normal operating temperature of the device using the structure. Any metal that does not melt even at a high temperature or a voltage of 4.3 V or higher can be used without particular limitation. Non-limiting examples of such metals include nickel, copper, aluminum, titanium, chromium, carbon, iron, cobalt, molybdenum, gold, silver, vanadium, SUS, and the like, and alloys thereof may also be used. These may be used alone or in combination of two or more.

1 is a plan view showing an example of a structure for an electrochemical device according to the present invention, a hollow cylindrical tube 10 and the first member 20 and the second made of a polymer for sealing both ends of the hollow cylindrical tube The structure for an electrochemical device of the first form including the member 30 and including an ionic salt therein is shown. The polymer member and the end of the hollow tubular tube can be sealed by connecting in the same manner as heat fusion, the member made of the polymer in such a structure is introduced into the end of the hollow tubular tube in a sealed form (sealing) will be.

2 and 3 show a hollow cylindrical tube 10; A first member (20) made of a polymer and sealing one end of the hollow cylindrical tube; And a second member 30 which is made of metal and seals the other end of the hollow cylindrical tube, and includes an ionic salt therein. As a plan view showing an example of the, the first member made of a polymer is introduced into one end of the hollow cylindrical tube in the form of a stopper and capsule, respectively.

Structure for an electrochemical device according to the second aspect of the present invention is a tube of two or more hollow cylindrical tube is connected up and down by the polymer; A third member sealing one end of the pipe connected vertically; And a fourth member for sealing the other end of the tube connected up and down, wherein the interior empty space of the structure includes an ionic salt.

The structure for an electrochemical device of the second form is a polymer that connects the two or more hollow tubular tubes at a temperature higher than the normal operating temperature of the device using the same or a voltage of 4.3V or more is melted and the tubes connected to each other vertically It can be separated, it is characterized in that the interior of the structure for the electrochemical device of the closed structure can be opened to the outside. At this time, the temperature higher than the normal operating temperature of the device is preferably 70 ~ 200 ℃.

In the structure for an electrochemical device of the second form, the polymer connecting the two or more hollow cylindrical tubes may exist, for example, in the form of a tube or a plate, but the shape and thickness thereof are not particularly limited.

In addition, the polymer connecting the two or more hollow cylindrical tubes is not particularly limited as long as it can be melted at a temperature higher than the normal operating temperature of the device using the electrochemical device structure or at a voltage of 4.3 V or more. Non-limiting examples of such polymers include silicone resins, acrylic resins, urethane resins, epoxy resins, rubber, polyethylene, polypropylene, polybutene, polyacetaldehyde, polyformaldehyde, polypropylene oxide, polymethylmethacrylate, polyvinyl And a vinylidene chloride, polyvinylidene fluoride, and the like, and these may be used alone or in combination of two or more thereof.

In the structure for an electrochemical device of the second form, the hollow cylindrical tube, the third member, and the fourth member may be each independently made of a polymer or a metal.

The polymer forming the hollow tubular tube, the third member and the fourth member is not particularly limited. Accordingly, the polymer forming the hollow cylindrical tube, the third member, and the fourth member may be the same or different components as those of the polymer connecting the two or more hollow cylindrical tubes, respectively. The polymer having a melting point higher than the melting point of the polymer connecting the two or more hollow cylindrical tubes, more preferably, does not melt at a temperature higher than the normal operating temperature of the device using the structure or at a voltage of 4.3 V or more. Anything that can be maintained can be used. Non-limiting examples thereof are the same as those of the polymer forming the hollow cylindrical tube described above in the electrochemical device structure of the first type.

In addition, the metal forming the hollow cylindrical tube, the third member and the fourth member is a metal having a melting point higher than the melting point of the polymer connecting the two or more hollow cylindrical tube, preferably of a device using a structure Any metal that does not melt at a temperature higher than the normal operating temperature or at a voltage of 4.3 V or higher can be used without particular limitation. Non-limiting examples thereof are the same as the examples of the metal for forming the hollow cylindrical tube described above in the electrochemical device structure of the first type.

4 is a plan view showing an example of the structure for an electrochemical device according to the present invention, in which two hollow cylindrical tubes 10 and 11 are connected up and down by a polymer 40 and both ends of the hollow cylindrical tube. It includes a third member 20 and the fourth member 30 made of a polymer for sealing the inside, there is shown a structure for an electrochemical device of the second form containing an ionic salt.

Structure for an electrochemical device according to the third aspect of the present invention comprises a hollow cylindrical tube having one or more openings on its surface and closed at both ends; And a polymer member for sealing the opening, wherein the internal void space of the structure includes an ionic salt.

In the third type electrochemical device structure, the polymer member sealing the opening at a temperature higher than the normal operating temperature of the device using the same or at a voltage of 4.3 V or more may be melted, whereby the electric The inside of the structure for a chemical device is characterized in that it can be opened to the outside. At this time, the temperature higher than the normal operating temperature of the device is preferably 70 ~ 200 ℃.

The form and size of the opening formed in the surface of the hollow cylindrical tube are not particularly limited.

The shape and size of the polymer member sealing the opening are not particularly limited. For example, the polymer member 50 may have a notch shape recessed into the hollow tubular tube 10 as shown in FIG. 5, or a scratch formed thinly on the surface of the hollow tubular tube 10 as shown in FIG. 6. It may be introduced into the structure in the form of a scratch, or in the form of an embossed convex protruding out of the hollow cylindrical tube 10 as shown in FIG.

In addition, the polymer member is not particularly limited as long as the polymer member can be melted at a temperature higher than the normal operating temperature of the device using the electrochemical device structure or at a voltage of 4.3 V or more. Non-limiting examples of such polymers include silicone resins, acrylic resins, urethane resins, epoxy resins, rubber, polyethylene, polypropylene, polybutene, polyacetaldehyde, polyformaldehyde, polypropylene oxide, polymethylmethacrylate, polyvinyl And a vinylidene chloride, polyvinylidene fluoride, and the like, and these may be used alone or in combination of two or more thereof.

In the third type electrochemical device structure, the hollow cylindrical tube may be made of a polymer or a metal.

The polymer forming the hollow cylindrical tube is not particularly limited. Therefore, the polymer forming the hollow tubular tube may be the same or different components as the polymer member, but preferably has a polymer having a melting point higher than that of the polymer member, more preferably a structure. It is possible to use those which can be maintained in their original form without melting even at temperatures higher than the device's normal operating temperature or voltages higher than 4.3V. Non-limiting examples thereof are the same as those of the polymer forming the hollow cylindrical tube described above in the electrochemical device structure of the first type.

In addition, the metal forming the hollow tubular tube does not melt at a temperature higher than the normal operating temperature of a device having a melting point higher than the melting point of the polymer member, preferably at a temperature higher than the normal operating temperature of a device using the structure. The metal can be used without particular limitation. Non-limiting examples thereof are the same as those of the metal forming the hollow cylindrical tube described above in the electrochemical device structure of the first type.

On the other hand, the electrochemical device structure according to the present invention is not limited to the electrochemical device structure of the first embodiment to the third embodiment, it also includes a structure of a combination of each of them.

In addition, the structure for an electrochemical device according to the present invention is not particularly limited in size.

The electrochemical device according to the present invention comprises an anode, a cathode, a separator, an electrolyte, a device case and a structure for an electrochemical device according to the present invention.

The electrochemical device of the present invention includes all devices that undergo an electrochemical reaction. Specific examples thereof include all kinds of primary cells, secondary batteries, fuel cells, solar cells, or capacitors. The electrochemical device is preferably a secondary battery, and a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery is preferable.

In the electrochemical device of the present invention, the electrochemical device structure may be included in an empty space or electrolyte in the device, or may be included as a center pin. Examples of the empty space in the device include, but are not limited to, a space between the electrode assembly in the jelly roll form and the device case, or a space between the electrode assembly in the jelly roll form and the pouch.

In addition, the ionic salt contained in the inner empty space of the structure for the electrochemical device at a temperature higher than the normal operating temperature of the electrochemical device according to the present invention or a voltage of 4.3V or more is released to the outside of the structure, the released The cations of the ionic salts migrate to the cathode and are reduced to precipitate as metals, and the anions of the ionic salts can migrate to the anode and oxidized to become gases.

In addition, the electrochemical device having a structure for an electrochemical device according to the present invention (a) a first safety means for stopping the charging of the device or switching the state of charge to a discharge state by detecting a pressure change in the device, Or (b) second safety means for detecting a change in pressure inside the device to dissipate heat or gas inside the device, or both the first safety means and the second means.

Non-limiting examples of first safety measures that can be used include pressure sensitive devices such as conventional CIDs known in the art. Or (i) the pressure sensitive device; (ii) conducting wires carrying current delivered from the pressure sensitive device; And (iii) a member for stopping charging of the device or switching the charging state to a discharge state in response to a current transmitted through the conductive wire.

At this time, the pressure sensitive device detects the pressure change in the sealed device, that is, the pressure rise and itself blocks the current, or generates a current toward the outside or the control circuit so that the charging of the electrochemical device does not proceed any further. As referred to, it may be an integrated unit including both the safety device function and the function of the pressure sensitive device, and as described above, the pressure sensitive device and the safety device may exist separately. However, the type or manner thereof is not particularly limited as long as the above operation is performed in a specific pressure range.

Examples of the pressure sensitive device include a crystal having piezoelectricity that senses a pressure change and generates a current. In addition, the pressure range in which the pressure sensitive device operates is not particularly limited so long as it is outside the conventional device internal pressure and no explosion occurs.

Further, the second safety means is not particularly limited as long as it functions to dissipate heat or gas inside the device by detecting a pressure change inside the device, and a non-limiting example thereof includes a pressure release valve such as a vent. .

When the electrochemical device according to the invention further comprises the first safety means and / or the second safety means, the structure for the electrochemical device at a temperature higher than the normal operating temperature of the electrochemical device or a voltage of 4.3V or more The ionic salt contained in the inner void space of the is released to the outside of the structure, the anion of the released ionic salt becomes a gas,

The first safety means, or the second safety means, or both the first safety means and the second safety means can be activated by sensing the pressure change inside the element increased by the gas, As a result, the safety of the electrochemical device can be improved.

The electrochemical device according to the present invention can be prepared according to conventional methods known in the art. For example, the electrochemical device structure according to the present invention is used as a center pin, and the electrode group having a separator interposed between the anode and the cathode is wound around the center pin in a jellyroll form. After forming the electrode assembly, it can be prepared by injecting the electrolyte into the device case.

In the electrochemical device according to the present invention the electrode can be prepared by conventional methods known in the art. For example, a slurry is prepared by mixing and stirring a solvent, a binder, a conductive material, and a dispersant in an electrode active material, if necessary, and then applying (coating) to a current collector of a metal material, compressing, and drying the electrode. Can be.

The electrode active material may be a positive electrode active material or a negative electrode active material.

The positive electrode active material may be _a lithium transition metal composite oxide such as LiM _x O _y (M = Co, Ni, Mn, Co _a Ni _b Mn _c ) (for example, lithium manganese composite oxide such as LiMn ₂ O ₄ , LiNiO _2, etc.). Lithium cobalt oxides such as lithium nickel oxide, LiCoO ₂ and manganese, nickel and cobalt portions of these oxides substituted with other transition metals, or lithium-containing vanadium oxide or the like, or chalcogenide compounds (for example, manganese dioxide) , Titanium disulfide, molybdenum disulfide, etc.) may be used. Preferably LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , Li (Ni _a Co _b Mn _c ) O ₂ (0 <a <1, 0 <b <1, 0 <c <1, a + b + c = 1), LiNi _1-Y Co _Y O ₂ , LiCo _1-Y Mn _Y O ₂ , LiNi _1-Y Mn _Y O ₂ (where 0 ≦ Y <1), Li (Ni _a Co _b Mn _c ) O ₄ (0 <a <2, 0 <b <2, 0 <c <2, a + b + c = 2), LiMn _2-z Ni _z O ₄ , LiMn _2-z Co _z O ₄ ( Here, 0 <Z <2), LiCoPO ₄ , LiFePO ₄ or a mixture thereof can be used.

The negative electrode active material may be a conventional negative electrode active material that can be used for the negative electrode of the conventional electrochemical device, non-limiting examples thereof lithium metal, lithium alloy, carbon, petroleum coke that can occlude and release lithium ions ), Activated carbon, graphite, carbon fiber, and the like. In addition, metal oxides such as TiO ₂ , SnO _2, and the like, which can occlude and release lithium, and have a potential with respect to lithium of less than 2V, can be used. In particular, carbon materials such as graphite, carbon fiber and activated carbon are preferable.

The current collector of the metal material may be any metal that has high conductivity and can easily adhere to the slurry of the electrode active material and is not reactive in the voltage range of the battery. Non-limiting examples of the positive electrode current collector include aluminum, nickel, or a foil produced by a combination of these. Non-limiting examples of the negative electrode current collector include copper, gold, nickel, or a copper alloy or a combination thereof Foil and so on.

Examples of usable binders include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and the like.

The conductive material is not particularly limited as long as it is an electronic conductive material that does not cause chemical change in the electrochemical device. Examples of the solvent include organic solvents such as NMP (N-methylpyrrolidone), DMF (dimethylformamide), acetone, and dimethylacetamide, and water. These solvents may be used alone or as a mixture of two or more thereof .

The electrolyte may include a nonaqueous solvent and an electrolyte salt, and may include water.

The nonaqueous solvent is not particularly limited as long as it is normally used as a nonaqueous solvent for a nonaqueous electrolyte, and cyclic carbonate, linear carbonate, lactone, ether, ester, sulfoxide, acetonitrile, lactam, and / or ketone can be used.

Examples of the cyclic carbonate include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), fluoroethylene carbonate (FEC), and the like. Examples of the linear carbonate include diethyl carbonate (DEC) and dimethyl carbonate. (DMC), dipropyl carbonate (DPC), ethylmethyl carbonate (EMC), methyl propyl carbonate (MPC), and the like. Examples of the lactone include gamma butyrolactone (GBL), and examples of the ether include dibutyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, and the like. Examples of the ester include methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, butyl propionate, methyl pivalate and the like. The sulfoxide includes dimethyl sulfoxide, the lactam includes N-methyl-2-pyrrolidone (NMP), and the ketone includes polymethylvinyl ketone. Moreover, the halogen derivative of the said organic solvent can also be used. These non-aqueous solvents may be used alone or in combination of two or more.

The electrolyte salt is not particularly limited as long as it is usually used as an electrolyte salt for nonaqueous electrolyte. Electrolytic salt, non-limiting example, A ⁺ B ^- up to a salt of the same structure, and A ⁺ is Li ^+, Na ^+, K ^+, and contains such an alkali metal cation or a cation made of a combination of B ^- is PF _{^{6 -, BF 4 -, Cl}} -, Br -, I -, ClO 4 -, AsF 6 -, CH 3 CO 2 -, CF 3 SO 3 -, N (CF 3 SO 2) 2 -, C (CF 2 And an anion consisting of anions such as SO ₂ ) ₃ ⁻ or a combination thereof, and a salt consisting of a combination of the cation and an anion. In particular, lithium salts are preferred. These electrolyte salts may be used alone or in combination of two or more.

The separator is not particularly limited, but it is preferable to use a porous separator, and non-limiting examples include a polypropylene-based, polyethylene-based, or polyolefin-based porous separator.

The electrochemical device of the present invention is not limited in appearance, but may be cylindrical, square, pouch or coin type using a can.

[Example]

Hereinafter, the present invention will be described in detail with reference to examples. However, the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[Production of Electrochemical Device Structure]

(Example 1)

₃ g of Al ₂ (SO ₄ ) ₃ g was inserted into a hollow cylindrical tube made of PE and having a diameter of 3 mm and a length of 50 mm, and then both ends of the hollow cylindrical tube were heat-sealed using epoxy resin. Sealed to prepare a structure for an electrochemical device.

(Example 2)

An electrochemical device structure was manufactured in the same manner as in Example 1, except that both ends of the hollow cylindrical tube were sealed by heat fusion without using an epoxy resin.

(Example 3)

An electrochemical device structure was manufactured in the same manner as in Example 1, except that an aqueous NaCl solution (a supersaturated solution: 40%) was used instead of Al ₂ (SO ₄ ) ₃ .

(Example 4)

An electrochemical device structure was manufactured in the same manner as in Example 1, except that an aqueous solution of MgCl ₂ (supersaturated solution: 50%) was used instead of Al ₂ (SO ₄ ) ₃ .

(Example 5)

An electrochemical device structure was manufactured in the same manner as in Example 1, except that a hollow tubular tube made of PP was used.

[Production of Electrochemical Device]

(Example 6)

94% by weight of LiCoO ₂ as a positive electrode active material, 3% by weight of acetylene black as a conductive material and 3% by weight of PVDF as a binder were mixed and added to NMP (N-methyl-2-pyrrolidone) to prepare a positive electrode slurry. Al) was applied and dried on the current collector to prepare a positive electrode.

95% by weight of artificial graphite was used as a negative electrode active material, and 5% by weight of PVDF as a binder was added to NMP to prepare a negative electrode slurry, and then coated and dried on a copper (Cu) current collector to prepare a negative electrode.

The electrolyte was prepared by dissolving LiPF ₆ in a non-aqueous solvent having a composition of ethylene carbonate (EC): ethyl methyl carbonate (EMC) = 1: 2 (v: v) to a concentration of 1 M.

A porous polyethylene film was used as the separator, and the electrochemical device structure prepared in Example 1 was used as the center pin.

The strip-shaped cathode and the strip-shaped anode were laminated on the separator, and the rolls were wound several times around the center pin to prepare a jelly roll. This was housed in a battery can having an outer diameter of 18 mm and a height of 65 mm, and an insulating plate was disposed on both upper and lower surfaces of the electrode element. Then, the negative electrode lead made of nickel was drawn from the current collector and welded to the battery can. The positive electrode lead made of aluminum was drawn from the positive electrode current collector and welded to the aluminum pressure release valve mounted on the battery cover. To prepare a battery.

(Examples 7-10)

A battery was manufactured in the same manner as in Example 6, except that the electrochemical device structures prepared in Examples 2 to 5 were used as center pins, respectively.

(Comparative Example 1)

A battery was manufactured in the same manner as in Example 6, except for using the general center pin of a hollow cylindrical type of SUS material in which both ends were not sealed, instead of the electrochemical device structure prepared in Example 1 as the center pin.

(Comparative Example 2)

The electrolyte was prepared by adding 5 parts by weight of Al ₂ (SO ₄ ) ₃ to 100 parts by weight of the electrolyte prepared in Example 6,

The center pin was manufactured in the same manner as in Example 6 except for using the general center pin of a hollow cylindrical shape made of SUS instead of the electrochemical device structure prepared in Example 1.

[Safety test experiment]

The battery prepared in Examples 6 to 10 and Comparative Examples 1 and 2 was charged to 4.3V and then subjected to a 1 m / min Nail test to evaluate safety, and the results are shown in Table 1 below. Pass in Table 1 shows that there is no ignition and explosion.

Test Result (Pass Count / Test Count) Example 6 3/5 Example 7 5/5 Example 8 5/5 Example 9 5/5 Example 10 3/5 Comparative Example 1 0/5 (all fail, fire) Comparative Example 2 No test result (no charging)

According to Table 1, it can be seen that the battery of Examples 6 to 10 using the electrochemical device structure of the present invention as a center pin has improved safety by reducing the frequency of ignition or explosion compared to the battery of Comparative Example 1. .

[Battery Performance Evaluation Experiment]

In order to evaluate the performance of the battery prepared in Examples 6 to 10 and Comparative Examples 1 and 2, the rate characteristic and the cycle characteristic were confirmed, and the results are shown in Table 2 below.

Battery 1C capacity was based on 2200mAh.

0.2C 1.0C Cycle (300 cycle,%) Remarks Example 6 2230 mAh 2210 mAh 76% Example 7 2230 mAh 2200 mAh 78% Example 8 2234 mAh 2212 mAh 79% Example 9 2231 mAh 2209 mAh 80% Example 10 2230 mAh 2211 mAh 79% Comparative Example 1 2234 mAh 2213 mAh 79% Comparative Example 2 - - - Can't charge

According to the above Table 2, the battery prepared in Examples 6 to 10 showed the rate and cycle characteristics almost the same as the battery containing the general center pin (Comparative Example 1), so that the charging and discharging at the steady state of the present invention It was confirmed that there was no change in performance of the battery depending on whether or not the electrochemical device structure was included. On the other hand, in a battery in which the ionic salt was directly added to the electrolyte (Comparative Example 2), the battery performance could not be realized because it was not charged due to the electrochemical side reaction from the initial formation stage.

Meanwhile, the present invention described above is merely exemplary, and the present invention is not limited thereto, and various modifications can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. It belongs to the scope of the present invention.

The structure for an electrochemical device according to the present invention is an enclosed structure having an empty space therein, and includes an ionic salt in an internal empty space that can improve the safety of the electrochemical device using the structure of the present invention. , The amount of material included in the empty space can be easily adjusted.

Further, the structure according to the present invention does not affect the device when the temperature and voltage inside the device including the same are normal, but when the temperature inside the device becomes abnormally high temperature or overvoltage due to overcharge, A portion of the structure may be melted to a high molecular weight so that the ionic salt contained in the empty space inside the structure may be released to the outside of the structure.

As such, the cation of the ionic salt released to the outside of the structure is reduced while consuming electrons at the cathode included in the device, thereby suppressing a rise in temperature due to rapid flow of current, and the anion of the released ionic salt is a nonflammable gas at the anode. By oxidizing to form the inside of the device in a non-flammable atmosphere can improve the safety of the device. In addition, the safety means provided in the device by the generated gas can be activated early to improve the safety of the device.

Claims (24)

Hollow tubular tubes; A first member made of a polymer and sealing one end of the hollow cylindrical tube; And a second member made of a polymer or metal and sealing the other end of the hollow cylindrical tube. The hollow tubular tube is made of a polymer or metal, Melting point of the polymer or metal constituting the hollow tubular tube is higher than the melting point of the first member and the second member, An electrochemical device structure comprising an ionic salt in an internal empty space. The electrochemical method of claim 1, wherein the first member, or both the first member and the second member, are melted at a temperature higher than a normal operating temperature of the device using the electrochemical device structure or at a voltage of 4.3 V or more. Structure for device. The structure of claim 2, wherein the temperature higher than the normal operating temperature of the device is 70 ~ 200 ℃. The ionic salt of claim 1, wherein the ionic salt is selected from the group consisting of Al ₂ (SO ₄ ) ₃ , Ca (OH) ₂ , Mg (NO ₃ ) ₂ , PbI ₂ , NaCl, MgCl ₂ and Al ₂ (OH) ₃ . Electrochemical device structure characterized in that at least one selected. The method of claim 1, wherein the polymer constituting the first member and the polymer constituting the second member are each independently silicone resin, acrylic resin, urethane resin, epoxy resin, rubber, polyethylene, polypropylene, polybutene, polyacetaldehyde , Polyformaldehyde, polypropylene oxide, polymethyl methacrylate, polyvinylidene chloride, polyvinyl fluoride and polyvinylidene fluoride structure for an electrochemical device, characterized in that at least one member. delete Two or more hollow tubular tubes connected up and down by a polymer; A third member sealing one end of the pipe connected vertically; And a fourth member sealing the other end of the pipe connected vertically, The hollow tubular tube, the third member, and the fourth member are each independently made of a polymer or a metal, An electrochemical device structure comprising an ionic salt in an internal empty space. The electrochemical device according to claim 7, wherein the polymers connecting the two or more hollow cylindrical tubes are melted at a temperature higher than a normal operating temperature of the device using the electrochemical device structure or at a voltage of 4.3 V or more. Structure. The structure of claim 8, wherein the temperature higher than the normal operating temperature of the device is 70 ~ 200 ℃. 8. The method of claim 7, wherein the ionic salt is from the group consisting of Al ₂ (SO ₄ ) ₃ , Ca (OH) ₂ , Mg (NO ₃ ) ₂ , PbI ₂ , NaCl, MgCl ₂ and Al ₂ (OH) ₃ . Electrochemical device structure characterized in that at least one selected. The method of claim 7, wherein the polymer connecting the two or more hollow cylindrical tubes is silicone resin, acrylic resin, urethane resin, epoxy resin, rubber, polyethylene, polypropylene, polybutene, polyacetaldehyde, polyformaldehyde, poly A structure for an electrochemical device, characterized in that at least one member selected from the group consisting of propylene oxide, polymethyl methacrylate, polyvinylidene chloride, polyvinyl fluoride and polyvinylidene fluoride. delete A hollow tubular tube having one or more openings on a surface thereof and closed at both ends; And a structure comprising a polymer member for sealing the opening, An electrochemical device structure comprising an ionic salt in an internal empty space. The electrochemical device structure of claim 13, wherein the polymer member is melted at a temperature higher than a normal operating temperature of the device using the electrochemical device structure or at a voltage of 4.3V or more. 15. The structure of claim 14, wherein the temperature higher than the normal operating temperature of the device is 70-200 ° C. The method of claim 13, wherein the ionic salt is from the group consisting of Al ₂ (SO ₄ ) ₃ , Ca (OH) ₂ , Mg (NO ₃ ) ₂ , PbI ₂ , NaCl, MgCl ₂ and Al ₂ (OH) ₃ . Electrochemical device structure characterized in that at least one selected. The method of claim 13, wherein the polymer member is a silicone resin, acrylic resin, urethane resin, epoxy resin, rubber, polyethylene, polypropylene, polybutene, polyacetaldehyde, polyformaldehyde, polypropylene oxide, polymethyl methacrylate, Electrochemical device structure, characterized in that consisting of at least one selected from the group consisting of polyvinylidene chloride, polyvinyl fluoride and polyvinylidene fluoride. The structure of claim 13, wherein the hollow cylindrical tube is made of a polymer or a metal. An electrochemical device comprising an anode, a cathode, a separator, an electrolyte, a device case, and the structure for an electrochemical device according to any one of claims 1 to 5, 7 to 11, and 13 to 18. . 20. The electrochemical device of claim 19, wherein the electrochemical device is a secondary battery. 20. The electrochemical device of claim 19, wherein the electrochemical device structure is included in an empty space or electrolyte in the device or as a center pin. 20. The method of claim 19, wherein the ionic salt contained in the internal void space of the structure for the electrochemical device at a temperature higher than the normal operating temperature of the electrochemical device or a voltage of 4.3V or more is released to the outside of the structure, the release The cation of the ionic salt to be precipitated as a metal, the anion of the ionic salt is characterized in that the gas. 20. The device of claim 19, wherein the electrochemical device comprises: (a) first safety means for sensing a change in pressure inside the device to stop charging the device or to switch the charging state to a discharged state, or (b) inside the device An electrochemical device, characterized in that it further comprises a second safety means for detecting a change in pressure of the heat or gas inside the device, or both the first safety means and the second means. 24. The method of claim 23, wherein the ionic salt contained in the internal empty space of the structure for the electrochemical device at a temperature higher than the normal operating temperature of the electrochemical device or a voltage of 4.3V or more is released to the outside of the structure, the release The anions of the ionic salts being gaseous, And sensing the pressure change inside the device increased by the gas so that the first safety means, or the second safety means, or both the first safety means and the second safety means operate.

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