KR101122428B1 - Gas-generating strucrure and lithium secondary battery comprising the same - Google Patents

Abstract

The present invention (a) a first compound; (b) a second compound capable of generating a gas by chemical reaction upon contact with the first compound; And (c) a third compound which does not cause a chemical reaction with the first compound and the second compound, and has a melting point lower than the melting point of the first compound and the melting point of the second compound. A gas generating structure in which physical contact between the second compound and the second compound is blocked, wherein the first compound and the second compound are in contact with each other when the third compound is melted to generate a gas generating chemical reaction; And it relates to a lithium secondary battery characterized in that the gas generating structure is introduced into the inside or outside of the battery.

The gas generating structure of the present invention can not only generate gas at a predetermined temperature (T) or more, but also can control the gas generating temperature, and there are a wide variety of compounds that can be used, and can be usefully used throughout the industry. have.

Description

GAS-GENERATING STRUCRURE AND LITHIUM SECONDARY BATTERY COMPRISING THE SAME

1 is a graph of gas generation according to the temperature of lauroyl peroxide of Experimental Example 1. FIG.

2 to 6 are schematic views of a gas generating structure according to an embodiment of the present invention. Here, yellow is the first compound, blue is the second compound, and red is the third compound.

7 is a schematic view showing a mechanism in which the safety means of the battery is operated by the gas generating structure of the fully sealed elastic body according to the present invention when the lithium secondary battery rises above a predetermined temperature (T).

8 is a surface temperature and voltage graphs of Examples 6, 7, 8 and Comparative Example 1 cells during overcharging according to Experimental Example 2. FIG.

The present invention relates to a gas generating structure in which the gas generating chemical reaction between the compounds can be made only above a certain temperature (T).

Throughout the industry, compounds or devices capable of generating gases at certain temperatures are very useful. For example, such compounds (or devices) are also being applied to the lithium secondary battery field, which has been attracting attention as the interest in energy storage technology is increasing recently.

Secondary batteries generally include a positive electrode, a negative electrode, a separator, and a nonaqueous electrolyte. When such a secondary battery reaches a critical temperature due to high temperature exposure, safety problems may occur due to exothermic decomposition and combustion of the nonaqueous electrolyte. In particular, when the battery is overcharged, the cathode active material may be deformed into a thermally unstable structure due to a large amount of lithium leaving, and may release oxygen, which may accelerate decomposition or combustion of the nonaqueous electrolyte. The battery safety problem can be more serious.

In order to solve this problem, a method of mechanically interrupting current during overcharging, for example, a method of introducing a safety means such as a current interrupt device (CID) -reverse into a battery has been proposed. The CID-reverse is a device that blocks the flow of current through the cell and prevents additional current flow when the internal pressure of the battery increases, and thus sufficient internal pressure increase is required before ignition and rupture of the battery to secure the safety of the battery.

In order to increase the internal pressure of the battery, compounds that can generate gas by thermally decomposing themselves above a certain temperature such as azo and peroxide compounds have been used. However, such a compound is very limited in kind, and pyrolysis reaction may proceed even below a specific temperature, and thus there is a problem in that durability is weak.

The present invention includes a first compound and a second compound capable of generating a gas by chemical reaction with each other upon contact, and the physical contact between the first compound and the second compound does not cause a chemical reaction with the first compound and the second compound And a gas generating structure that is blocked by a third compound having a melting point lower than that of the first compound and a melting point of the second compound. The gas generating structure has a predetermined temperature (T) or more through a state change according to the temperature of the third compound. It is intended to provide a gas generating structure that is controlled so that only the first compound and the second compound can come into contact with each other to cause a gas generating chemical reaction.

The present invention (a) a first compound; (b) a second compound that may generate gas upon chemical reaction upon contact with the first compound; And (c) a third compound which does not cause a chemical reaction with the first compound and the second compound, and has a melting point lower than the melting point of the first compound and the melting point of the second compound. A gas generating structure in which physical contact between the second compound and the second compound is blocked, wherein the first compound and the second compound are in contact with each other when the third compound is melted to generate a gas generating chemical reaction; And it provides a lithium secondary battery characterized in that the gas generating structure is introduced into the inside or outside of the battery.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

Secondary batteries, in which safety measures are activated when the internal pressure of the battery increases, generally use a gas generating material in or outside the cell. Such a gas generating material may generate gas only at a certain temperature, and the amount of gas generated is It needs to be enough to work. As such a gas generating material, a compound (hereinafter, a conventional gas generating material) capable of generating a gas by thermally decomposing itself above a certain temperature such as an azo or peroxide compound may be used, but such a compound has a very limited kind. There is.

In addition, the gas generating material may not generate enough gas to enable the safety means to operate. For example, lauroyl peroxide at 80 ° C In the above-described compounds that can self-decompose and generate gas, when stored under high temperature, there is a problem that the amount of gas generated is significantly reduced and durability is weak (see Experimental Example 1 and FIG. 1). That is, in the case of a conventional gas generating material, the safety of the device may not be sufficiently secured.

The gas generating structure of the present invention includes a first compound and a second compound capable of generating a gas by chemical reaction upon contact with the first compound, and whether or not physical contact between the first compound and the second compound according to temperature By adjusting, the first compound and the second compound are in contact with each other only at a predetermined temperature (T) to control the gas generation chemical reaction.

Specifically, the gas generating structure of the present invention does not cause a chemical reaction with the first compound and the second compound, the first compound by the third compound having a melting point lower than the melting point of the first compound and the second compound And physical contact of the second compound is blocked, and when the third compound is melted at a predetermined temperature (T) or more, the first compound and the second compound are brought into contact with each other to cause a gas generating chemical reaction. All.

Embodiment of the gas generating structure of the present invention

In the gas generating structure of the present invention, the physical contact between the first compound and the second compound is blocked by the third compound, and the first compound and the second compound contact when the third compound melts at a predetermined temperature (T) or more. If possible, there is no particular limitation on its configuration, form, and the like. The gas generating structure may be implemented in various embodiments, and preferably the following two embodiments are possible.

In the first aspect of the gas generating structure of the present invention, the first compound, the second compound, and the third compound are sequentially arranged in the structure of the first compound, the third compound, and the second compound, and thus the first compound and the second compound. Physical contact of the compound is blocked by the third compound. At this time, the direction of the sequential arrangement of the first compound, the second compound, and the third compound is not particularly limited, and the transverse direction may be possible. 4, 6). This is because physical contact of the first compound and the second compound upon melting of the third compound is facilitated by gravity, so that gas generation can be induced quickly. Further, in order to facilitate physical contact between the first compound and the second compound during melting of the third compound, the sequential arrangement of the first compound, the second compound, and the third compound may be performed by the first compound-third compound-second compound-agent. It is preferable that the compound is repeated in the order of the third compound to the first compound.

In addition, in the second aspect of the gas generating structure of the present invention, the third compound is coated on the surface of at least one of the first compound and the second compound, so that physical contact between the first compound and the second compound is blocked by the third compound. (See Fig. 5). For example, a first core-shell and a second compound comprising a core of the first compound and a shell of the third compound; A second core-shell and a first compound comprising a core of the second compound and a shell of the third compound; Alternatively, the first core-shell and the second core shell may be mixed. The second aspect has the advantage that the distance of the first compound and the second compound for physical contact during melting of the third compound is short, so that gas generation can be induced quickly.

The first compound and the second compound are not particularly limited as long as they can generate a gas by chemical reaction with each other upon contact. For example, the first compound and the second compound may be compounds that generate gas through a wide range of redox reactions, such as neutralization reactions. That is, any one of the first compound and the second compound may be an oxidizing agent, the other may be a reducing agent, and by way of non-limiting example, any one of the first compound and the second compound may be an acid or a base, and the other may be a metal. , Carbonate, sulfite, or ammonium salt, and the first compound and the second compound may each include two or more compounds. Examples of the combination of the first compound and the second compound include a combination of one or more of hydrochloric acid, sulfuric acid, acetic acid, and metals (eg, aluminum, zinc, etc.); Combinations of at least one of sodium hydroxide, potassium hydroxide, triethylamine and metals; Combinations of at least one of sodium carbonate, potassium carbonate and acids; A combination of at least one of sodium chlorite (NaClO), potassium permanganate and hydrogen peroxide; Combinations of sulfites and acids, and combinations of ammonium salts and bases.

In addition, it is preferable that the first compound and the second compound are liquid phases having excellent mobility for ease of physical contact between the two compounds during melting of the third compound. At this time, the liquid form includes a form dissolved in a solvent (溶媒).

On the other hand, the third compound does not cause a chemical reaction with the first compound and the second compound, the melting point (mp) is lower than the melting point of the first compound and the melting point of the second compound (T) to generate gas It will not specifically limit, if it is a compound above. The third compound may be a fatty acid compound, an alcohol compound, or a high molecular compound, and the high molecular compound may be a mixture of one or more oligomers, polymers, or other additives, thereby controlling melting point. Non-limiting examples of the fatty acid compounds include arachidic acid (mp: 74-76 ℃), undecanedicarboxylic acid (mp: 112 ℃), lauric acid (mp: 44-46 ℃) ), Myristic acid (mp: 52-54 ° C), palmitic acid (mp: 61-62 ° C), stearic acid (mp: 67-72 ° C), docosanoic acid, mp: 72-80 ° C), azelaic acid (mp: 109-111 ° C), sebacic acid (mp: 133-137 ° C), suberic acid (mp: 140-144) ℃, pimelic acid (mp: 103-105 ℃), 1,10-decanedicarboxylic acid (1,10-decanedicarboxylic acid, mp: 127-129 ℃) and the like, examples of the alcohol compound is xylitol ( xylitol, mp: 94-97 ° C.).

As described above, since a wide range of compounds can be used as the gas generating material in the present invention, the problem that the type of the conventional gas generating material is very limited can be solved.

In addition, the gas generating structure of the present invention may vary the temperature (T) at which the gas generating chemical reaction between the first compound and the second compound occurs by changing the third compound. For this reason, the gas generating structure of the present invention can be usefully used throughout the industry, such as a lithium secondary battery. For example, when the gas generating structure of the present invention is applied to a lithium secondary battery, the temperature T at which the gas generating chemical reaction between the first compound and the second compound occurs is normal to that of the lithium secondary battery having or equipped with the gas generating structure. It is preferred to be adjusted to a temperature range higher than the operating temperature, such as 50 to 200 ° C.

<Case of Gas Generating Structure of Present Invention>

The case accommodating the gas generating structure of the present invention is not particularly limited and various forms may be applied. For example, the case may be implemented in two forms as described below depending on the mechanism of operation of the gas generating structure.

The first type of the case is a hollow cylindrical tube, in which the gas generating structure of the present invention is introduced into a lithium secondary battery (for example, used as a core or a center pin), and when the temperature rises above a certain temperature T, By releasing the generated gas to the outside, the volume and the internal pressure of the battery can be increased, whereby the safety means of the battery can be operated. At this time, the hollow cylindrical tube can maintain the gas generating compounds (first compound, the second compound, and the third compound) inside the structure, while the gas generated inside when the temperature rises above a certain temperature (T). One side is sealed and it is preferable to have an opening part in a part so that it may discharge | emit to.

The closed one side may be one end of the tube is thermally fused as it is, or the first polymer member may be formed by being connected to one end of the tube by thermal fusion. In this case, it is preferable that the first polymer member has a higher melting point than the first compound, the second compound, and the third compound. In addition, the opening may be an unopened side of the tube or one or more openings closed by the second polymer member and opened by the melting of the second polymer member. In this case, it is preferable that the melting point of the second polymer member is at or above a temperature T at which gas is generated in the tube.

On the other hand, the hollow cylindrical tube may be made of a metal, ceramic or polymer. In this case, it is preferable that the hollow tubular tube is not melted in the normal operating voltage / temperature range of the device to which the gas generating structure of the present invention is applied and can maintain its original shape.

Non-limiting examples of the metal include nickel, copper, aluminum, titanium, chromium, carbon, iron, cobalt, molybdenum, gold, silver, vanadium, SUS or alloys thereof. In addition, non-limiting examples of the polymer include ethylene vinyl acetate (EVA), polystyrene, polyphenylene ether (PPE), polychlorotrifluoroethylene, polyvinyl chlorite (PVC), polyethylene terephthalate (PET), poly Amide, Polycaprolactam, Polycarbonate (PC), Poly- (p-Xylene), Polyimide (PI), Polyoxybenzoate (POB), Polyetheretherketone (PEEK), Polyphenylenesulfide (PPS) , Polyethersulfone (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, which may be used alone or in combination.

In addition, the second embodiment of the case is a hermetically sealed elastomer, wherein the gas generating structure of the present invention is introduced under the safety means of the lithium secondary battery, and is caused by the generation of internal gas when rising above a certain temperature T. By acting as a physical switching through volume expansion, it can be applied in the case of promoting the operation of the safety means (see FIG. 7).

In addition, the hermetically sealed elastomer may be a core-shell structure in which gas generating compounds (first compound, second compound, and third compound) are introduced into an internal space, and may be a multi-core-shell structure. For example, a first core-shell including a core of a first compound and a shell of a third compound inside the case, and a double core-shell structure having a second compound introduced outside the first core-shell. (See FIG. 6).

<Lithium secondary battery of this invention>

In addition, the present invention provides a lithium secondary battery in which the above-described gas generating structure is introduced inside or outside.

The lithium secondary battery of the present invention may be a lithium secondary battery such as a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery or a lithium ion polymer secondary battery.

In addition, the lithium secondary battery of the present invention, by detecting a pressure change in the battery, (a) a first safety means for stopping the charging of the battery or switching the state of charge to a discharge state; And (b) second safety means for dissipating heat or gas inside the battery to the outside.

Non-limiting examples of the first safety means that can be used include pressure sensitive elements such as conventional CID known in the art. The pressure sensitive element may be integral, or (i) a pressure sensitive member; (ii) conducting wires for delivering current delivered from the pressure sensitive member; 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 element detects the pressure change in the sealed battery, that is, the pressure rise and itself blocks or discharges the current, or generates current toward the external or control circuit, thereby further charging the lithium secondary battery. It refers to a device that is not to be discharged or discharged, and 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 element include a crystal having piezoelectricity that senses a pressure change and generates a current. Further, the pressure range in which the pressure sensitive element operates is not particularly limited as long as it is within a range in which the pressure inside the normal element does not occur and no explosion occurs, but is preferably in the range of 5 to 20 kg / cm 2.

In addition, the second safety means is not particularly limited as long as it functions to dissipate heat or gas (eg, flammable gas) inside the battery by detecting a pressure change inside the battery, and a non-limiting example thereof may include a vent or the like. Such as pressure release valves.

On the other hand, the position in which the above-described gas generating structure is introduced into the lithium secondary battery according to the present invention is not particularly limited, but in order to ensure the safety of the battery and not affect the performance of the battery, the gas generating structure is electrochemical reaction (electrochemical reaction) is preferably introduced into the empty space inside the battery, such as inside the mandrel, the center pin (center pin), the inner top of the battery case, the bottom or two or more areas thereof. . For example, the gas generating structure of the present invention may be introduced as a mandrel or center pin itself of the battery as described above, or may be introduced under the battery's safety means (eg vent).

On the other hand, the gas generating structure of the present invention may be mounted on the outside of the lithium secondary battery, wherein the gas generating structure is connected to the safety means of the battery, and the temperature detection unit for detecting and transferring the temperature change inside the battery to the structure; It is preferable.

The lithium secondary battery of the present invention may be manufactured according to conventional methods known in the art, except for introducing the above-described gas generating structure into the battery. For example, the above-described gas generating structure is used as a center pin, and the electrode group having a separator interposed between the anode and the cathode is wound in a jelly roll form around the center pin. After forming the electrode assembly, it may be prepared by placing it in a battery case and injecting an electrolyte solution.

Although the external shape of the lithium secondary battery according to the present invention is not limited, it is possible to have a cylindrical, coin-shaped, square or pouch type of can.

The present invention will be described in more detail with reference to the following examples and comparative examples. However, the following examples are intended to illustrate the present invention, and the scope of the present invention is not limited thereto.

(Manufacture of gas generating structure)

Example 1

Hydrochloric acid is added to the sealed side of the PE tubular container and sealed with stearic acid (mp: 69.6 ° C.), and then aluminum foil is placed on the other side of the container.

When the vessel is heated to about 70 ° C. or more, stearic acid melts and hydrochloric acid and aluminum foil contact and chemically react to generate gas.

Example 2

Put 0.3M citric acid aqueous solution into the sealed one side of the tubular container made of PE and seal it with stearic acid, and then place calcium carbonate on the other side of the container.

When the vessel is heated to about 70 ° C. or more, stearic acid melts and the citric acid aqueous solution and calcium carbonate contact and chemically react to generate gas.

Example 3

Stearic acid is coated on the surface of aluminum foil by injecting aluminum foil into liquid stearic acid and taking it out. It is added to a tubular container of PE (1.5 mm in diameter), and further hydrochloric acid is added.

When the vessel is heated to about 70 ° C. or more, stearic acid melts and hydrochloric acid and aluminum foil contact and chemically react to generate gas.

Example 4

Hydrochloric acid is added to the sealed side of a tubular vessel (diameter of 1.5 mm) made of a polymer (poly (ethylene glycol) methyl ether-block-polylactide) film having a melting point of 90 ° C., and the other side of the vessel is heat-sealed as it is. And then surround the container with aluminum foil.

When the vessel is heated to about 90 ° C. or more, the tubular vessel is melted, and hydrochloric acid and aluminum foil contact and chemically react to generate gas.

Example 5

0.1 g of citric acid and 0.4 g of stearic acid are mixed and heated to about 70 ° C. to dissolve and solidify the stearic acid to prepare a first core-shell consisting of a core of citric acid and a shell of stearic acid. A second core-shell consisting of a core of calcium carbonate and a shell of stearic acid was prepared in the same manner as above using 0.1 g of calcium carbonate and 0.4 g of stearic acid.

The first core-shell and the second core-shell are mixed and introduced into a tubular container made of PE (1.5 mm in diameter), and then heated to about 70 ° C. or more. At this time, as stearic acid is fused, citric acid and calcium carbonate are contacted and chemically reacted to generate gas.

(Manufacture of lithium secondary battery)

Example 6

Using the gas generating structure of Example 1 as a center pin, and wound the electrode group with a separator interposed between the anode and the cathode around the center pin in the form of a jelly roll to form an electrode assembly, this The electrolyte was injected into the device case to prepare a cylindrical secondary battery equipped with a CID. In this case, LiCoO _{2 is used} as the anode, MAG-E is used as the cathode, and a porous membrane made of polyethylene is used as the separator. The electrolyte solution has a volume ratio of FEC: PC: DMC = 2: 1: 7 and PRS 3% by weight, SN 1 A 1M LiPF ₆ solution having a composition of weight percent, PS 2 weight percent was used.

Example 7

A cylindrical secondary battery was manufactured in the same manner as in Example 6, except that the gas generating structure of Example 2 was used as a center pin instead of the gas generating structure of Example 1.

Example 8

A cylindrical secondary battery was manufactured in the same manner as in Example 6, except that the gas generating structure of Example 3 was used as a center pin instead of the gas generating structure of Example 1.

Comparative Example 1

A cylindrical secondary battery was manufactured in the same manner as in Example 6, except that a conventional hollow cylindrical tube not containing any compound therein was used as a center pin instead of the gas generating structure of Example 1.

Experimental Example 1

0.10 g of lauroyl peroxide was stored at -5 ° C. for 30 days, 60 ° C. for 4 days, and 30 days, respectively, and placed in a container to measure internal pressure change with temperature rise. The results are shown in Fig.

As a result, lauroyl peroxide, which was left at 60 ℃ for more than 4 days, had about 1/3 less gas generation at 100 ℃ than when it was left at -5 ℃ for 30 days. From this, it can be seen that the conventional gas generating material (lauroyl peroxide) may not actually generate a sufficient amount of gas under the overcharging temperature of the battery, thereby causing a problem that the safety of the battery is not guaranteed.

Experimental Example 2

The cylindrical secondary batteries of Examples 6, 7, 8 and Comparative Example 1 were overcharged under the conditions of 10V and 1C, and the presence or absence of CID short circuit, the surface temperature of the battery, and whether the battery was ignited / exploded were measured. 8 is shown.

In FIG. 8, the secondary battery of Example 8 in which the gas generating structure of the present invention was used as the center pin showed a sudden increase in voltage before the secondary battery of Comparative Example 1 in which the conventional center pin was used. Since the increase in voltage is assumed to be caused by the operation of the CID mounted on the battery, it was confirmed that the battery of Example 8 according to the present invention can operate the CID earlier than the battery of Comparative Example 1. In addition, in the CID operation, the secondary battery of Comparative Example 1 using a conventional center pin exhibited a temperature of about 120 ° C., whereas the batteries of Examples 6, 7, and 8 according to the present invention exhibited about 100 ° C.

From this, it is understood that the gas generating structure of the present invention is introduced into a lithium secondary battery, thereby generating gas when the battery is out of the normal operating temperature range, thereby promoting early operation of safety means and ensuring battery safety. Could.

The gas generating structure of the present invention can not only generate gas at a predetermined temperature (T) or more, but also can control the gas generating temperature, and there are a wide variety of compounds that can be used, and can be usefully used throughout the industry. have.

Claims (26)

(a) a first compound; (b) a second compound that may generate gas upon chemical reaction upon contact with the first compound; And (c) a third compound which does not cause a chemical reaction with the first compound and the second compound and has a melting point lower than that of the first compound and that of the second compound, A gas generating structure in which physical contact between the first compound and the second compound is blocked by the third compound, The gas generating structure, characterized in that when the third compound is melted, the first compound and the second compound may come into contact with each other to cause a gas generating chemical reaction. The method of claim 1, wherein the first compound, the second compound, and the third compound are sequentially arranged in the structure of the first compound, the third compound, and the second compound in the structure, thereby physically contacting the first compound and the second compound. A gas generating structure characterized by being blocked by this third compound. 3. The gas generating structure according to claim 2, wherein the sequential arrangement directions of the first compound, the second compound, and the third compound are in the longitudinal direction, the transverse direction, or the center to the outward direction. 3. The gas generating structure according to claim 2, wherein the sequential arrangement of the first compound, the second compound, and the third compound is repeated. The method of claim 1, wherein the third compound is coated on the surface of at least one of the first compound and the second compound, the physical contact between the first compound and the second compound is blocked by the third compound Structure. The gas generating structure according to claim 1, wherein one of the first compound and the second compound is an oxidizing agent and the other is a reducing agent. The gas generating structure according to claim 1, wherein any one of the first compound and the second compound is an acid or a base, and the other is a metal, a carbonate, sulfite or ammonium salt. The gas generating structure according to claim 1, wherein at least one of the first compound and the second compound is a liquid phase. The gas generating structure according to claim 1, wherein the third compound is a fatty acid compound, an alcohol compound or a high molecular compound. The method of claim 9, wherein the third compound is arachidic acid (arachidic acid), undecanedicarboxylic acid (laudecanedicarboxylic acid), lauric acid (lauric acid), myristic acid (myristic acid), palmitic acid (palmitic acid) , Stearic acid, docosanoic acid, azelaic acid, sebacic acid, suberic acid, pimelic acid, 1,10-decane Gas generating structure, characterized in that selected from the group consisting of carboxylic acid (1,10-decanedicarboxylic acid) and xylitol (xylitol). delete delete The gas generating structure of claim 1, wherein the case includes: a hollow tubular tube; Or a gas tight structure, which is a hermetically sealed elastomer. The gas generating structure according to claim 13, wherein the hollow tubular tube can discharge gas generated inside the structure to the outside. The gas generating structure according to claim 13, wherein one side of the hollow cylindrical tube is closed and an opening is formed on a part of the surface. The gas generating structure according to claim 13, wherein the fully enclosed elastic body is expanded in volume by gas generation inside the structure. The gas generating structure according to claim 13, wherein the fully enclosed elastic body has a core-shell structure in which gas generating compounds are introduced into an inner space. The lithium secondary battery of claim 1, wherein the gas generating structure of claim 1 is introduced inside or outside. 19. The method of claim 18, wherein the lithium secondary battery comprises: (i) first safety means to stop charging the battery or to change the charging state to a discharge state by detecting a pressure change inside the battery; and (ii) heat inside the battery. Or at least one selected from the group consisting of second safety means for dissipating gas to the outside. The rechargeable lithium battery of claim 19, wherein the first safety means comprises a pressure sensitive element. 20. The device of claim 19, wherein the first safety means is (i) a pressure sensitive member; (ii) conducting wires for delivering current delivered from the pressure sensitive member; And (iii) a member for stopping charging of the battery or switching the charging state to a discharge state in response to a current transmitted through the conductive wire. 20. The lithium secondary battery of claim 19 wherein said second safety means is a pressure release valve. 19. The battery interior bin of claim 18, wherein the gas generating structure is selected from the group consisting of a mandrel, a center pin, an inner top of the battery case, and an inner bottom of the battery case. A lithium secondary battery characterized by being introduced into a space. The lithium secondary battery according to claim 18, wherein the gas generating structure is introduced as a mandrel or a center pin of the battery. The lithium secondary battery according to claim 19, wherein the gas generating structure is introduced under the first safety means or the second safety means. delete

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