JP2015046247A - Gel electrolyte precursor, method for manufacturing gel electrolyte, method for manufacturing lithium ion secondary battery, and lithium ion secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a gel electrolyte precursor which enables the formation of a gel electrolyte having an adequate viscosity or hardness as a gel electrolyte of a battery; and a lithium ion secondary battery including such a gel electrolyte.SOLUTION: A gel electrolyte precursor comprises: a nonaqueous solvent; an electrolyte; at least one cross-linking compound A having three or more oxirane rings; and at least one cross-linking compound B having one or two oxirane rings. In the gel electrolyte precursor, each oxirane ring is a cyclohexene oxide group. The gel electrolyte precursor includes, as the at least one cross-linking compound A, at least one compound selected from a group consisting of compounds expressed by the general formulas (A-1) and (A-2) below.

Description

  The present invention relates to a gel electrolyte precursor, a method for producing a gel electrolyte using the gel electrolyte precursor, a method for producing a lithium ion secondary battery using the gel electrolyte precursor, and a lithium ion secondary comprising the gel electrolyte. Next battery.

  In recent years, with the diversification of portable electronic devices and the accompanying rapid increase in the number of shipments, the demand for secondary batteries with high output and high capacity is increasing. Secondary batteries are also important as high-performance storage batteries such as hybrid cars and electric cars that have been put on the market to prevent global warming, reduce air pollution, and reduce fossil fuel consumption. Further, even in ordinary households, a large capacity and high performance secondary battery is required as an energy storage device for energy management at the level of individual houses by leveling power consumption and combining with solar cells.

  There are many types of secondary batteries used in these portable devices, automobiles, houses, etc., such as lead storage batteries, nickel metal hydride batteries, nickel cadmium batteries, and lithium ion batteries. Among these, a lithium ion secondary battery can obtain a high potential, has a large energy density, and has a small memory effect. Therefore, the lithium ion secondary battery is particularly suitable for applications in which additional charging is performed such as portable devices, automobiles, and houses.

  On the other hand, since a lithium ion secondary battery has high performance, it is necessary to perform charge and discharge with a controlled and good balance. If the charge / discharge protection circuit is insufficient, the inside of the battery will be in a very strong oxidized state or reduced state, which will destabilize the materials inside the battery. In particular, when the battery is overcharged, metallic lithium deposits inside the battery, not only deteriorating the battery, but also causing serious accidents such as breakage of the sealing agent due to heat generation, spillage of the electrolyte, and ignition. there is a possibility.

For such problems, measures are taken at each level, such as improving the robustness of the charge / discharge management system, ensuring structural safety, and ensuring the safety of individual member surfaces.
Among the measures described above, examples of safety measures related to the electrolytic solution include solidification or gelation of the electrolytic solution. Attempts have been made to reduce or avoid the outflow of the electrolyte by preventing the corrosion or ignition around the battery by solidifying or gelling the electrolyte. Typical examples of solidification or gelation of the electrolyte include those using an inorganic solid electrolyte (Patent Document 1), those solidified or thickened by a polymer such as polyethylene oxide (Patent Document 2), polyfluorination Those using a vinylidene-hexafluoropropylene copolymer (Patent Document 3) are known.

  The safety of the secondary battery can be secured to some extent by gelling or solidifying the electrolyte. However, in the methods of Patent Documents 1 to 3, since the electrolytic solution is in a gel state or a solid state from the preparation stage before being injected into the cell, it is not possible to use a conventional battery manufacturing process and battery manufacturing apparatus. However, there is a problem that a dedicated manufacturing process and a manufacturing apparatus for arranging the gel electrolyte or the solid electrolyte in the cell are required.

  For the above problem, in Patent Document 4, in the manufacturing process, a gelling material is added to a liquid electrolyte (electrolytic solution), the electrolytic solution is injected into the cell, and then the gelling material is reacted in the cell. Have proposed a method of gelling the electrolyte. According to this method, the conventional manufacturing process and manufacturing apparatus can be used without change, and it becomes possible to deal with various battery forms.

International Publication No. 2013/024724 JP-A-10-189050 JP-T 8-507407 Japanese Patent No. 4597294

  However, as a specific example of the reaction for gelling the electrolytic solution, it is difficult to control the gelation reaction in the cell by a general method such as epoxy crosslinking, isocyanate crosslinking, and acrylic crosslinking described in Patent Document 4. There is a problem.

  Usually, in order to start reaction of epoxy crosslinking and isocyanate crosslinking, it is necessary to heat an electrolyte solution. However, the problem that the components of the electrolytic solution deteriorate due to the heating tends to occur. Currently, a common lithium salt used in an electrolytic solution is lithium hexafluorophosphate, but it is known that thermal decomposition of lithium hexafluorophosphate starts at 60 ° C. In Patent Document 4, a crosslinking reaction is performed at 70 ° C. For example, in the case of an electrolytic solution containing lithium hexafluorophosphate, deterioration of the electrolyte due to heating cannot be avoided.

  Further, in order to apply radical polymerization, it is necessary to add a radical initiator to the electrolytic solution. However, the radical initiator is unstable and it is difficult to make it exist stably in the electrolytic solution. Further, when a radical initiator that is stably present in the electrolytic solution is used, it is necessary to heat in order to cleave the initiator, and the electrolyte is likely to deteriorate.

  On the other hand, cationic polymerization is optimal for gelation of an electrolyte because the reaction proceeds even at low temperatures if there is a catalyst such as an acid. However, since the reaction starts in cationic polymerization when an acid or the like as a reaction catalyst comes into contact with the crosslinking agent, it is difficult to control the reaction rate. In addition, since the reaction rate and reaction rate cannot be controlled, it is difficult to adjust the physical properties of the gel obtained by the crosslinking reaction.

  The present invention has been made in view of the above circumstances, and a gel electrolyte precursor capable of forming a gel electrolyte having an appropriate viscosity or hardness as a gel electrolyte of a battery, and production of a gel electrolyte using the gel electrolyte precursor It is an object of the present invention to provide a method, a method for producing a lithium ion secondary battery using the gel electrolyte precursor, and a lithium ion secondary battery including the gel electrolyte.

[1] A gel containing a non-aqueous solvent, an electrolyte, at least one crosslinkable compound A having three or more oxirane rings, and at least one crosslinkable compound B having one or two oxirane rings. Electrolyte precursor.
[2] The gel electrolyte precursor according to [1], wherein the oxirane ring has a cyclohexene oxide group.
[3] As the crosslinkable compound A, [1] containing any one or more selected from the group consisting of compounds represented by the following general formula (A-1) and the following general formula (A-2) ] Or the gel electrolyte precursor according to [2].

［式（Ａ−１）中、ａ，ｂ，ｃ，ｄはそれぞれ独立に０〜２の整数を表す。式（Ａ−２）中、ａ，ｂはそれぞれ独立に０〜２の整数を表す。］

[In Formula (A-1), a, b, c and d each independently represents an integer of 0 to 2. In formula (A-2), a and b each independently represent an integer of 0 to 2. ]

[4] The crosslinkable compound B according to any one of the above [1] to [3], which contains any one or more compounds selected from the following formulas (B-1) to (B-4). The gel electrolyte precursor described.

[5] Any one of [1] to [4], wherein the content ratio (A: B) of the crosslinkable compound A and the crosslinkable compound B is in the range of 95: 5 to 1:99 by weight. The gel electrolyte precursor according to item.
[6] One of the above [1] to [5], wherein the total weight of the crosslinkable compound A and the crosslinkable compound B with respect to the total weight of the gel electrolyte precursor is 1 to 20% by weight. The gel electrolyte precursor according to item.
[7] An acid is allowed to act on the gel electrolyte precursor according to any one of [1] to [6] to crosslink the crosslinkable compound A and the crosslinkable compound B to obtain a gel electrolyte. A method for producing a gel electrolyte.
[8] Lithium ion secondary, including a step of injecting the gel electrolyte precursor according to any one of [1] to [6] into a battery container and a step of gelling the gel electrolyte precursor. A method for manufacturing a secondary battery.
[9] A lithium ion secondary battery including a gel electrolyte manufactured by the manufacturing method according to [7].

According to the gel electrolyte precursor of the present invention, a gel electrolyte having an appropriate viscosity or hardness can be obtained as a gel electrolyte for a battery. Since the gel electrolyte having an appropriate viscosity or hardness is difficult to leak out of the battery container, a battery having excellent safety can be obtained by using the gel electrolyte.
Moreover, the said crosslinkable compound A which comprises the gel electrolyte precursor of this invention can advance a crosslinking reaction on mild conditions. For this reason, in the gelation by the crosslinking reaction, the electrolyte contained in the gel electrolyte precursor is prevented from being modified or decomposed, and a gel electrolyte having an appropriate viscosity or hardness is obtained as the gel electrolyte of the battery.
Furthermore, when the gel electrolyte obtained from the gel electrolyte precursor of the present invention is used in a lithium ion secondary battery, excellent battery characteristics equivalent to those obtained when using a conventional electrolyte solution that does not gelate can be obtained. That is, when the gel electrolyte according to the present invention is used, it is possible to suppress deterioration of battery characteristics that can generally occur by gelling the electrolytic solution.

  According to the method for producing a gel electrolyte of the present invention, by adjusting the amount of reactive groups of the gel electrolyte precursor, gelation can be performed at a moderate reaction rate that is easy to control. By utilizing this gentle gelation reaction, in the battery manufacturing process, the liquid gel electrolyte precursor before gelation can be handled in the same manner as a conventional electrolyte.

  According to the method for producing a lithium ion secondary battery of the present invention, the conventional apparatus and process for producing a battery filled with an electrolytic solution can be applied with almost no change, and the gel electrolyte precursor is placed in the battery container. By completing the gelation after filling the body, a battery in which liquid leakage is prevented can be efficiently manufactured at low cost.

  In the lithium ion secondary battery of the present invention, since the gel electrolyte provided in the battery has an appropriate viscosity or hardness, there is no risk of liquid leakage and the safety is improved. Moreover, there is almost no deterioration of the battery characteristic by gelling, and it has the outstanding battery characteristic equivalent to the conventional electrolyte solution.

  First, the background that the present inventors have studied in finding the configuration of the gel electrolyte precursor of the present invention will be described below.

<About gelation of the electrolyte solution a which contains the crosslinkable compound A and does not contain the crosslinkable compound B>
When an electrolyte solution a containing only the crosslinkable compound A having three or more oxirane rings as a crosslinking group and not containing the crosslinkable compound B having one or two oxirane rings in a nonaqueous solvent containing an electrolyte is prepared. It is easy to gel this electrolytic solution a, but since the chemical crosslinking density in the gel becomes high, the gel becomes a high hardness. Since the movement of ions in a hard gel can be hindered, a gel that is softer and has a lower chemical crosslink density is desired. In order to form a flexible gel, it is theoretically conceivable to reduce the concentration of the crosslinkable compound A to a minimum concentration necessary for gelation. However, finding this minimum concentration is extremely difficult. If the concentration of the crosslinkable compound A is too low, gelation itself becomes difficult. On the other hand, if the concentration is surely increased, the gel hardness cannot be reduced to a desired level.
Furthermore, in the electrolytic solution a, since the crosslinking reaction tends to be prolonged without stopping at an appropriate time, a high-density bridge exceeding an assumption may be formed. In this case, the solvent (liquid component) containing the electrolyte may be pushed out (excluded) from the gel and separated into two phases of the gel and the liquid component.

<About the gelation of the electrolyte solution b which does not contain the crosslinkable compound A and contains the crosslinkable compound B>
On the other hand, an electrolyte solution b containing only the crosslinkable compound B having one or two oxirane rings as a crosslinking group and not containing the crosslinkable compound A having three or more oxirane rings in a nonaqueous solvent containing an electrolyte is prepared. In this case, it is difficult to gel the electrolyte b.
When the electrolytic solution b-1 is prepared using a compound having one oxirane ring, a linear polyether is generated in the electrolytic solution b-1 by cationic ring-opening polymerization of the oxirane ring. However, in order to gel or thicken the electrolyte b-1 with only a linear polyether, a large amount of the compound is required. When a large amount of the crosslinkable compound B is thus contained, the ratio of the electrolyte (ion conductive material) in the electrolytic solution b-1 is relatively reduced. In a battery using such an electrolytic solution b-1, the battery performance is clearly deteriorated.
Further, when the electrolytic solution b-2 is prepared using a compound having two oxirane rings, the electrolytic solution b-2 can be gelled, but, similarly to the electrolytic solution b-1, It is necessary to contain a large amount of the crosslinkable compound B. Even in a battery using such an electrolytic solution b-2, the battery performance deteriorates.

  As a result of intensive studies to solve the above problems, the present inventors have obtained a crosslinkable compound A having three or more oxirane rings as a crosslinkable group and a crosslinkable compound B having one or two oxirane rings. By mixing, the adjustment range of the concentration of the crosslinkable compounds A and B necessary for obtaining a gel having an appropriate viscosity or hardness is wide, the gelation rate can be adjusted, and the physical properties (viscosity or (Hardness) was also found to be controllable, and the present invention was completed.

  Hereinafter, preferred embodiments of the gel electrolyte precursor of the present invention will be specifically described.

《Gel electrolyte precursor》
Preferred embodiments of the gel electrolyte precursor of the present invention include a non-aqueous solvent, an electrolyte, at least one crosslinkable compound A having three or more oxirane rings, and a crosslinkable compound having one or two oxirane rings. And at least one B.

<Opening of oxirane ring with acid>
An oxirane ring as a bridging group is preferred because it undergoes cationic ring-opening polymerization by a catalytic action of a small amount of acid present in the electrolytic solution, and the crosslinking reaction proceeds gently.
The trace amount of acid present in the electrolyte includes, for example, Bronsted acid resulting from the reaction of a trace amount of water inevitably contained in the non-aqueous solvent and the electrolyte, and the electrolyte dissolved in the non-aqueous solvent. Examples thereof include a Lewis acid generated by heating and other acid components added to a non-aqueous solvent.

  Examples of the Bronsted acid include, as an electrolyte, hydrogen fluoride (fluoride fluoride) produced by hydrolysis of a lithium salt such as lithium hexafluorophosphate and lithium tetrafluoroborate with a small amount of water contained in a non-aqueous solvent. Hydrogen acid).

Examples of the Lewis acid include phosphorus pentafluoride (PF ₅ ) produced by heating lithium salts such as lithium hexafluorophosphate and lithium tetrafluoroborate dissolved as an electrolyte in a non-aqueous solvent. Examples thereof include boron trifluoride (BF ₃ ). This heating also generates hydrogen fluoride.

  In order to initiate cationic ring-opening polymerization of the crosslinkable compound A and the crosslinkable compound B by the catalytic action of a small amount of acid present in the electrolytic solution, no special treatment is required, and crosslinking is performed with the electrolyte in a non-aqueous solvent. By dissolving the functional compound A and the crosslinkable compound B, polymerization (crosslinking reaction) can be started gently. Examples of the method for promoting or accelerating the crosslinking reaction include a method for increasing the concentration of the aforementioned Lewis acid and Bronsted acid by heating the electrolyte. Furthermore, the cross-linking reaction may be further accelerated or accelerated by adding a stimulus-responsive acid generator that generates acid by stimulation of heat, light, or the like in the electrolytic solution.

<Crosslinkable compound>
In the present specification, specific examples of the crosslinkable compound A having three or more oxirane rings and the crosslinkable compound B having one or two oxirane rings are shown below, but the crosslinkable compound A and the crosslinkable used in the present invention are shown below. Compound B is not limited to this.
The crosslinkable compound A and the crosslinkable compound B may each independently be a monomer having an oxirane ring, or may be a polymer in which the monomer is polymerized.

  Examples of the polymer include phenol novolac epoxy resins. In addition, a 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol represented by the following formula (X-1) can also be exemplified. Any compound having three or more oxirane rings in a single molecule can be used as the crosslinkable compound A of the present embodiment, not limited to the compounds exemplified here. Further, any compound having one or two oxirane rings in a single molecule can be used as the crosslinkable compound B of the present embodiment.

When the compound represented by the formula (X-1) is the crosslinkable compound A, in the formula, n represents an integer of 3 or more, preferably 3 to 10, more preferably 3 to 7, and 3 to 5 Further preferred.
When the compound represented by the formula (X-1) is the crosslinkable compound B, n represents an integer of 1 or 2.

  In the formula (X-1), R represents a hydrocarbon group. The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. A part of carbon atoms constituting the hydrocarbon group may be substituted with a heteroatom such as nitrogen, oxygen or sulfur. The number of carbon atoms of the hydrocarbon group is not particularly limited, and examples thereof include 1 to 30. Examples of the hydrocarbon group include an alkyl group and an alkenyl group. The alkyl group may be linear, branched or cyclic. The alkyl group preferably has 1 to 10 carbon atoms, and the alkenyl group preferably has 2 to 10 carbon atoms.

  The oxirane ring of the crosslinkable compound A and the crosslinkable compound B preferably has a substituent other than a hydrogen atom bonded to at least one of two carbon atoms bonded to the oxygen atom constituting the oxirane ring. More preferably, the substituent is bonded to both of the two carbon atoms. When the substituent is bonded to both of the two carbon atoms, the reactivity of the oxirane ring can be increased.

  As said substituent, the coupling group which consists of a monovalent hydrocarbon group, a single bond, or a bivalent hydrocarbon group is mentioned, for example.

  The monovalent hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. A part of carbon atoms constituting the monovalent hydrocarbon group may be substituted with a heteroatom such as nitrogen, oxygen or sulfur. The number of carbon atoms of the monovalent hydrocarbon group is not particularly limited, and examples thereof include 1 to 30. Examples of the monovalent hydrocarbon group include an alkyl group and an alkenyl group. The alkyl group may be linear, branched or cyclic. The alkyl group preferably has 1 to 10 carbon atoms, and the alkenyl group preferably has 2 to 10 carbon atoms. When there are a plurality of the substituents, the plurality of substituents may be bonded to each other to form a ring together with two carbon atoms bonded to the oxygen atom constituting the oxirane ring.

  When the substituent is an alkyl group, a compound in which one or more alkyl groups are bonded to both of two carbon atoms constituting the oxirane ring, that is, a compound in which the oxirane ring has two or more alkyl groups as a substituent. , Crosslinkable Compound A or Crosslinkable Compound B is an example. The two or more alkyl groups may be bonded to each other to form a ring. Examples of the compound having this ring include compounds in which an oxirane ring is condensed to a cyclohexane ring or a cyclopentane ring.

  The substituent is preferably a linking group comprising a single bond or a divalent hydrocarbon group. That is, the crosslinkable compound A and the crosslinkable compound B preferably have a group containing an oxirane ring. The group containing an oxirane ring is bonded to the remaining part of the crosslinkable compound A and the crosslinkable compound B.

  Some or all of the carbon atoms constituting the divalent hydrocarbon group may be substituted with heteroatoms such as oxygen, nitrogen, sulfur and the like. Further, when there are a plurality of the divalent hydrocarbon groups, the plurality of substituents may be bonded to each other to form a ring together with two carbon atoms bonded to the oxygen atom constituting the oxirane ring. This ring may have one bond (a carbon atom that can be bonded to another group), or may have two or more bonds. The divalent hydrocarbon group is preferably a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms.

Examples of the group containing an oxirane ring include a cyclohexene oxide group, an epoxy group, a glycidyl group, and the like.
The cyclohexene oxide group is preferable because it is easily obtained by allowing an oxidizing agent to act on cyclohexene, has high reactivity, and is easily available.

The gel electrolyte precursor of the present embodiment is selected from the group consisting of compounds represented by the following general formula (A-1) and the following general formula (A-2) as the crosslinkable compound A having three or more cyclohexene oxide groups. It is preferable to contain any one or more selected.
By gelling the gel electrolyte precursor of this embodiment containing these crosslinkable compounds A, a gel electrolyte having a viscosity or hardness suitable for the use of the lithium ion secondary battery and excellent in ionic conductivity is obtained. Can be easily obtained.

In the formula (A-1), a, b, c and d each independently represent an integer of 0 to 2. All of a to d in the formula (A-1) are preferably 0 to 1, and more preferably 1.
In said formula (A-2), a and b represent the integer of 0-2 each independently. A and b in the formula (A-2) are preferably 0 to 1, and more preferably 1.

The gel electrolyte precursor of this embodiment is selected from the group consisting of compounds represented by the following formulas (B-1) to (B-14) as the crosslinkable compound B having one or two cyclohexene oxide groups. It is preferable to contain any one or more of them. The compounds represented by the following formulas (B-1) to (B-14) should be contained in combination with the crosslinkable compound A represented by the general formula (A-1) and the general formula (A-2). Is preferred.
When the gel electrolyte precursor of this embodiment containing these crosslinkable compounds B is gelled, a gel electrolyte having a viscosity or hardness suitable for the use of the lithium ion secondary battery and excellent in ion conductivity is obtained. Can be easily obtained.

  In the general formula (B-13), R represents a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms.

  In addition to the crosslinkable compound B having a cyclohexene oxide group, examples of the crosslinkable compound B having a glycidyl group include commercially available epoxy resin bases such as bisphenol A diglycidyl ether and bilphenol F diglycidyl ether.

In the crosslinkable compound A and the crosslinkable compound B constituting the gel electrolyte precursor of the present embodiment, it is preferable that an oxirane ring having two or more substituents described above is included rather than a glycidyl ether type oxirane ring. More preferably, it contains a cyclohexene oxide group condensed to a cyclohexane ring.
The gel electrolyte precursor of the present embodiment containing these suitable crosslinkable compound A and crosslinkable compound B is gelled, thereby having a viscosity or hardness suitable for the use of the lithium ion secondary battery, and ion conduction A gel electrolyte having excellent properties can be easily obtained.

<Content ratio of crosslinkable compounds A and B>
In the gel electrolyte precursor of the present embodiment, the content ratio (A: B) of the crosslinkable compound A and the crosslinkable compound B is preferably in the range of 95: 5 to 1:99 by weight ratio, The range of 90:10 to 3:97 is more preferable, and the range of 80:20 to 5:95 is more preferable.
By gelling the gel electrolyte precursor in the above preferred content ratio range, a gel electrolyte having a viscosity or hardness suitable for the use of the lithium ion secondary battery and excellent in ion conductivity can be easily obtained. .

<Concentration of crosslinkable compound A>
The content of the crosslinkable compound A with respect to the total weight of the gel electrolyte precursor of the present embodiment is preferably 1% by weight or more, more preferably 1.5 to 10% by weight, and further preferably 2 to 7% by weight.

  In the gel electrolyte precursor of the present embodiment, the content of the crosslinkable compound A usually needs to be 1% by weight or more. By containing 1% by weight or more of the crosslinkable compound A, the crosslink density of the obtained gel electrolyte can be increased, and physical properties such as viscosity and hardness of the gel electrolyte can be easily adjusted. In addition, in this embodiment, when using 2 or more types of crosslinkable compound A, the said content means content of the sum total of multiple types of crosslinkable compound A. FIG.

<Concentration of crosslinkable compound B>
The content of the crosslinkable compound B with respect to the total weight of the gel electrolyte precursor of the present embodiment is preferably 5% by weight or more, more preferably 6 to 15% by weight, and even more preferably 7 to 10% by weight.

  In the gel electrolyte precursor of this embodiment, by containing 5% by weight or more of the crosslinkable compound B, it is possible to suppress the crosslinking density of the resulting gel electrolyte from becoming too high, and to improve physical properties such as viscosity and hardness of the gel electrolyte. It can be adjusted easily. Usually, the more crosslinkable compound B is added, the lower the crosslink density and the relatively soft gel electrolyte can be obtained. Further, by containing 5% by weight or more of the crosslinkable compound B, the upper limit value of the content of the crosslinkable compound A can be increased, and the adjustment range of the content of the crosslinkable compound A can be widened. Moreover, since the compound which has one oxirane ring among the crosslinkable compounds B can function as a regulator which extends the distance of the oxirane rings as a crosslinking group in a gel, the said content ratio is considered in consideration of this. It is preferable to adjust. In addition, in this embodiment, when using 2 or more types of crosslinkable compound B, the said content means content of the sum total of multiple types of crosslinkable compound B. FIG.

<Total weight of crosslinkable compounds A and B>
The total weight of the crosslinkable compound A and the crosslinkable compound B relative to the total weight of the gel electrolyte precursor of the present embodiment is preferably 1 to 20% by weight, although it depends on the type of each compound. 15 weight% is more preferable and 4 to 10 weight% is further more preferable.
When the total weight is less than 1% by weight, gelation by formation of a crosslinked structure is usually difficult. On the other hand, when the total weight exceeds 20% by weight, the ionic concentration or ionic conductivity conducted in the gel electrolyte relatively decreases. The performance of a battery provided with such a gel electrolyte may deteriorate.

<About crosslinkable functional groups other than oxirane ring>
In the gel electrolyte precursor of the present embodiment, a compound having a crosslinkable functional group capable of cationic polymerization other than the oxirane ring may be included as an additive component that is not an essential component.
Oxetane rings and tetrahydrofuran rings are known as cyclic ethers capable of cationic ring-opening polymerization in the same manner as oxirane rings.

  Examples of the compound having an oxetane ring include 3-ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane and xylylenebisoxetane as bifunctional compounds, Examples include ethylhexyl oxetane and 3-ethyl-3-hydroxymethyl oxetane (oxetane alcohol). A compound having an oxetane ring may be added to the gel electrolyte precursor of the present embodiment. However, since the oxetane ring is generally highly reactive, it must be added in consideration of it.

Since the tetrahydrofuran ring also undergoes cationic ring-opening polymerization, it may be added to the gel electrolyte precursor of this embodiment. However, since the ceiling temperature of the tetrahydrofuran ring is low and an equilibrium reaction between polymerization and dissociation tends to occur, it is necessary to add it in consideration of it.
In addition, 1,3,5-trioxane or the like can be added as a cyclic ether, and can be added as necessary.

  Furthermore, examples of compounds capable of cationic ring-opening polymerization include lactones such as β-propiolactone, and cyclic carbonates such as propylene carbonate. Since these are generally less reactive than cyclic ethers, they can be added in consideration of these.

  In addition, known compounds such as styrenes, hydrocarbon olefins, vinyl ethers, indenes, benzofurans, and 2,3-dihydrofurans may be added as compounds that undergo cationic addition polymerization.

  The compound having a crosslinkable functional group other than the oxirane ring described above should be added within the scope of the present invention in consideration of its reactivity, solubility, influence on gelation reaction, influence on battery performance, etc. Can do.

<Non-aqueous solvent>
The non-aqueous solvent constituting the gel electrolyte precursor of the present embodiment is not particularly limited as long as it is a solvent that can dissolve the crosslinkable compound A and the crosslinkable compound B and inhibits the crosslinking reaction by the oxirane ring. What is necessary is just to select suitably according to the kind and application. For example, a non-aqueous solvent used for an electrolyte of a known lithium ion secondary battery is applicable. The non-aqueous solvent preferably contains a trace amount of water to the extent that the above-described acid-opening reaction of the oxirane ring occurs.

  As a specific non-aqueous solvent, for example, a carbonate solvent having a high dielectric constant and a high boiling point such as ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate can be cited as a suitable solvent. Further, fatty acid esters and lactones may be added to the solvent. One type of non-aqueous solvent in this embodiment may be sufficient, and the mixed solvent in which 2 or more types were mixed may be sufficient.

<Electrolyte>
The electrolyte constituting the gel electrolyte precursor of the present embodiment is not particularly limited and can be appropriately selected according to the type and application of the battery.
When the gel electrolyte precursor of this embodiment is used for the production of a lithium ion secondary battery, a suitable supporting salt containing lithium ions is suitable for the electrolyte. Specifically, for example, fluorine inorganic salts such as lithium hexafluorophosphate and lithium tetrafluoroborate, lithium-bis (fluorosulfonyl) imide, lithium-bis (trifluoromethanesulfonyl) imide, lithium-bis (pentafluoroethane) And imides such as (sulfonyl) imide.

  As the electrolyte, an electrolyte that can generate Bronsted acid by being hydrolyzed by a small amount of water contained in the non-aqueous solvent, or a Lewis acid can be generated by heating in a non-aqueous solvent. Possible electrolytes are preferred. Examples of such an electrolyte include lithium hexafluorophosphate and lithium tetrafluoroborate as suitable electrolytes of the present embodiment.

The content of the electrolyte is preferably 1 to 25% by weight, more preferably 3 to 20% by weight, and still more preferably 5 to 18% by weight with respect to the total weight of the gel electrolyte precursor of the present embodiment.
When the above content is suitable, the crosslinkable compound A and the crosslinkable compound B having an oxirane ring are gently crosslinked to obtain a gel electrolyte having preferable ionic conductivity and physical properties as a gel electrolyte of a lithium ion secondary battery. Can be easily obtained.

<Other ingredients>
You may add an additive to the gel electrolyte precursor of this embodiment as needed.
As the additive, for example, an inorganic acid or a stimulus-responsive acid generator may be added for the purpose of promoting the ring-opening polymerization reaction of the oxirane ring of the crosslinkable compound A and the crosslinkable compound B. The addition concentration is appropriately adjusted according to the type and concentration of the crosslinkable compounds A and B used.

  Other additives include, for example, a material that forms a film called SEI that is generated between the electrode and the electrolyte (electrolyte) and stabilizes the electrode surface, and imparts flame retardancy to the electrolyte (electrolyte). For example, a flame retardant. Further, a thickener may be added as an additive to adjust to a desired viscosity.

<Method for Preparing Gel Electrolyte Precursor>
The gel electrolyte precursor of this embodiment can be prepared by uniformly mixing a non-aqueous solvent, an electrolyte, a crosslinkable compound A and a crosslinkable compound B, and other components as necessary. Each component may be mixed while sequentially adding them, or all components may be mixed together at one time. However, in consideration of the fact that gelation starts or accelerates when a component that initiates or accelerates the ring-opening polymerization reaction of the oxirane ring and the crosslinkable compound A and the crosslinkable compound B are mixed (gel) It is preferable to prepare the gel electrolyte precursor immediately before conversion.

  As a preferred method for preparing the gel electrolyte precursor of the present embodiment, first, an electrolytic solution in which a predetermined amount of electrolyte is dissolved in the non-aqueous solvent is prepared, and then a predetermined amount of the crosslinkable compound A and the cross-linked compound are added to the electrolytic solution. A method of obtaining the target gel electrolyte precursor by adding the functional compound B and stirring gently to sufficiently dissolve each component. In the non-aqueous solvent that constitutes the prepared gel electrolyte precursor, usually unavoidable water is present, so depending on the type of electrolyte, an acid is generated naturally, and a cross-linking polymerization reaction of the oxirane ring occurs. May be started gently. In consideration of this, it is preferable to prepare the gel electrolyte precursor immediately before manufacturing the gel electrolyte (immediately before gelation).

  The method of mixing each component is not particularly limited, and for example, a known method using a stirrer, a stirring blade, a ball mill, a stirrer, an ultrasonic disperser, an ultrasonic homogenizer, a self-revolving mixer, or the like can be applied. .

    Mixing conditions, such as mixing temperature and mixing time when preparing the gel electrolyte precursor of the present embodiment, avoid deterioration of the electrolyte and suppress the initiation or promotion of the ring-opening polymerization reaction of the oxirane ring. What is necessary is just to set suitably, considering.

For example, it is known that thermal decomposition of lithium hexafluorophosphate (LiPF ₆ ) starts at about 60 ° C. For this reason, when the electrolyte is a heat-sensitive lithium salt, the mixing temperature is preferably 4 to 70 ° C, more preferably 10 to 60 ° C, still more preferably 15 to 50 ° C, and more preferably 20 to 40 ° C. Particularly preferred. The mixing time is usually 1 to 30 minutes, preferably 1 to 20 minutes, more preferably 1 to 10 minutes.

《Gel electrolyte production method》
In a preferred embodiment of the method for producing a gel electrolyte of the present invention, a gel electrolyte is obtained by allowing a trace amount of acid to act on the gel electrolyte precursor and crosslinking the crosslinkable compound A and the crosslinkable compound B. Is the method.

  The method for causing a trace amount of acid to act on the gel electrolyte precursor is not particularly limited as long as it is a method for allowing an amount of acid capable of gently ring-opening polymerization of the oxirane ring. For example, a method (1) of adding a trace amount of an inorganic acid to a gel electrolyte precursor, a method (2) of applying a predetermined stimulus to a stimulus-responsive acid generator previously added to the gel electrolyte precursor, a gel electrolyte precursor There is a method (3) for generating an acid using a trace amount of water and an electrolyte contained in a non-aqueous solvent constituting the body.

  In the said method (1), the kind and addition amount of the inorganic acid to add can be suitably set according to the kind and content of the crosslinkable compound A and the crosslinkable compound B.

  In the said method (2), the kind and addition amount of the stimulus responsive acid generator to add can be suitably set according to the kind and content of the crosslinkable compound A and the crosslinkable compound B. For example, a known photoacid generator or thermal acid generator can be applied.

  As described above, the method (3) is a method using a Bronsted acid or Lewis acid such as hydrogen fluoride which is naturally generated in the gel electrolyte precursor. In order to promote the generation of the acid, the gel electrolyte precursor may be heated. The heating temperature is preferably a relatively low temperature that does not cause thermal decomposition of the electrolyte, and is preferably about 40 to 55 ° C, for example. The heating time is not particularly limited, and can be heated for 1 hour to several days as necessary.

In the manufacturing method of the gel electrolyte of this embodiment, the said method (3) is preferable. According to the method (3), gelation can be performed gently at a relatively slow crosslinking reaction rate. By gelling gently, a gel electrolyte having ionic conductivity and physical properties preferable as a gel electrolyte of a lithium ion secondary battery can be easily obtained.
Moreover, according to the said method (3), since it is not necessary to add an acid and an acid generator separately to a gel electrolyte precursor, a gel electrolyte can be manufactured simply.

 The gel electrolyte obtained by the production method of the present embodiment is a chemical gel having a crosslinked structure in which oxirane rings are chemically crosslinked. Chemical gels do not collapse easily when heat is applied. This characteristic is advantageous when used as a gel electrolyte of a lithium ion secondary battery. In a situation where some trouble occurs in the lithium ion secondary battery and there is a concern about leakage of the electrolyte or the like, there is a high possibility that the battery is abnormally heated. When a physical gel is used instead of a chemical gel, there is a high risk that the gel will melt and become liquid when heated by abnormal heat generation and leak out of the battery. On the other hand, there is almost no such risk in chemical gels.

 The gel electrolyte obtained by the production method of the present embodiment can be applied to known batteries such as primary batteries, secondary batteries, and fuel cells. Examples of the secondary battery include a lithium ion secondary battery.

<< Production Method of Lithium Ion Secondary Battery >>
A preferred embodiment of the method for producing a lithium ion secondary battery of the present invention includes a step (injection step) of injecting the gel electrolyte precursor of the present invention into the battery container, and a gel electrolyte injected into the battery container. And a step of gelling the precursor (gelation step).

  The “battery container” used in the injecting step broadly means a region (space) that can hold the gel electrolyte or the electrolytic solution in the lithium ion secondary battery. As such a space, for example, a space between a positive electrode plate and a negative electrode plate arranged to face each other can be cited. The narrow meaning of “battery container” means a container capable of holding a gel electrolyte or an electrolytic solution in a battery. In the present specification and claims, the term “battery container” includes both a broad meaning and a narrow meaning.

<Injection process>
In the injecting step, the method for injecting the gel electrolyte precursor into the battery container is not particularly limited, and a conventional apparatus and method for injecting an electrolytic solution can be applied. At this time, it is preferable to adjust the viscosity of the gel electrolyte precursor before gelation so low that the injection can be easily performed. The injection amount of the gel electrolyte precursor depends on the volume of the battery container, but may be the same as the injection amount of the electrolyte in the conventional lithium ion secondary battery. It is preferable that battery members such as a positive electrode, a negative electrode, and a separator are arranged in advance in the battery container. In the injection step, it is preferable that the fluidity of the gel electrolyte precursor is sufficiently maintained. The gel electrolyte precursor having sufficient fluidity sufficiently penetrates into the gaps between the respective members in the battery container, so that the electrochemical reaction necessary for exhibiting battery performance is appropriately performed. It is preferable to perform the following gelation step after the injection of the gel electrolyte precursor.

<Gelification process>
In the gelation step, as a method for gelling the gel electrolyte precursor injected into the battery container, any one of the method (1) to the method (3) is applied among the gel electrolyte production methods described above. It is preferable. In any method, the final sealing of the battery container may be performed at an appropriate time.

  When the method (1) is applied, an inorganic acid may be added to the gel electrolyte precursor in advance before injection, or the inorganic acid is separately added to the battery container before or after the gel electrolyte precursor is injected. It may be injected inside. Since it is easy to uniformly mix the inorganic acid into the gel electrolyte precursor, a method of adding a predetermined amount of the inorganic acid to the gel electrolyte precursor in advance before injection is more preferable. When the inorganic acid mixed in the gel electrolyte precursor advances the ring-opening polymerization of the oxirane ring, the gel electrolyte can be formed in the battery container.

  When the method (2) is applied, a stimulus-responsive acid generator may be added to the gel electrolyte precursor in advance before injection, or separately before or after the gel electrolyte precursor is injected. A responsive acid generator may be injected into the battery container. A method of adding a predetermined amount of a stimulus-responsive acid generator in advance to the gel electrolyte precursor before injection because it is easy to uniformly mix the stimulus-responsive acid generator in the gel electrolyte precursor Is more preferable. The stimulus-responsive acid generator is stimulated by light, heat, vibration, etc. to generate acid, and the generated acid promotes ring-opening polymerization of the oxirane ring, thereby forming a gel electrolyte in the battery container. Can do.

When the method (3) is applied, the gel electrolyte is formed in the battery container by advancing the ring-opening polymerization of the oxirane ring by the action of an acid (Bronsted acid or Lewis acid) naturally generated in the gel electrolyte precursor. Can be formed.
In this case, for the purpose of promoting the generation and diffusion of acid, a physical stimulus for heating or vibrating the gel electrolyte precursor in the battery container may be applied. In order to suppress thermal decomposition of the electrolyte, the heat treatment performed here is preferably performed in as short a time as possible with a temperature as low as possible, which is about 40 to 55 ° C., or as a standard with 1 hour to several days.

Other steps in the manufacturing method of the lithium ion secondary battery of the present embodiment are not particularly limited, and conventionally known methods can be applied.
As a pre-process of the said injection | pouring process, the process of incorporating the structural elements of batteries, such as a positive electrode, a negative electrode, a separator, in a battery container by a well-known method, for example is mentioned. Moreover, as a pre-process of the said gelatinization process, the process of deaerating the bubble which remains in a battery container after injection | pouring of a gel electrolyte precursor, and sealing (sealing) after that is mentioned, for example. Moreover, you may charge / discharge a battery as needed as a pre-process or a post-process of the said gelatinization process.

《Lithium ion secondary battery》
Preferred embodiments of the lithium ion secondary battery of the present invention include a lithium ion secondary battery provided with the gel electrolyte of the present invention and a lithium ion secondary manufactured by the method of manufacturing a lithium ion secondary battery of the present invention. It is a battery. In the lithium ion secondary battery of the present embodiment, the configuration other than the gel electrolyte is not particularly limited, and a conventionally known configuration of a lithium ion secondary battery can be applied.

  The basic structure of a general lithium ion secondary battery is often one in which a positive electrode, a gel electrolyte or electrolyte, a separator, and a negative electrode are sequentially stacked and installed in a battery container such as a film package or a can (metal container).

Examples of the configuration of the lithium ion secondary battery of the present embodiment include a positive electrode, a negative electrode, a gel electrolyte, a battery container, and a separator used as necessary.
Examples of the positive electrode include lithium cobaltate, lithium manganate, lithium nickelate, and lithium iron phosphate.
Examples of the negative electrode include titanate, silicon, germanium, etc., in addition to carbon-based materials such as graphite and hard carbon.

  The separator is a member that prevents direct contact between the positive electrode and the negative electrode, and is provided between the positive electrode and the negative electrode. Usually, the separator is a porous body, and an electrolytic solution (electrolyte) is held in the pores. As the material of the separator, a porous sheet made of polyolefin such as polypropylene is used. As the separator, when the battery abnormally generates heat, a porous hole may be blocked to block ion conduction, and a separator having a function of suppressing further reaction runaway may be applied.

Examples of the battery container include a resin film (laminate film) enclosing a laminate of the positive electrode, the separator, and the negative electrode, and a metal container.
The shape of the lithium ion secondary battery of the present embodiment is not particularly limited, and various shapes such as a cylindrical shape, a square shape, a coin shape, a sheet shape, and a film package shape can be applied.

  The amount of the gel electrolyte filled in the lithium ion secondary battery of the present embodiment may be the same as the electrolytic solution or gel electrolyte in a conventionally known lithium ion secondary battery.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.

[Example 1]
(Method for producing gel electrolyte precursor)
In a dry box, lithium hexafluorophosphate was dissolved in a mixed solvent of 25 vol% ethylene carbonate and 75 vol% diethyl carbonate so as to be 1 mol / L to obtain an electrolytic solution.
Tetra (3,4-epoxycyclohexylmethyl) ε caprolactone modified as a crosslinkable compound A (produced by Daicel Corporation, Epolide GT-401) (compound represented by the formula (A-1)), 3 ', 4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (made by Wako Pure Chemical Industries, Ltd.) as the crosslinkable compound B (compound represented by the above formula (B-1)), a weight ratio of 7 : The mixture mixed in 3 was added to the electrolyte solution so as to be 5% by weight to obtain a gel electrolyte precursor.

(Manufacture of lithium ion secondary batteries)
Using the gel electrolyte precursor produced above, a coin cell was produced using lithium cobaltate as the positive electrode, graphite as the negative electrode, and glass fiber as the separator. Specifically, the positive electrode, the separator, and the negative electrode punched in a disk shape are stacked in this order in a SUS battery container (such as CR2032), and the gel electrolyte precursor is injected into the battery container to stack The body was impregnated with a gel electrolyte precursor, and a SUS lid was placed on the negative electrode in the battery container to seal the battery container. Then, the lithium ion secondary battery provided with the gel electrolyte was manufactured by heating at 50 degreeC for 5 days, and gelatinizing the electrolyte solution in a battery container by the said method (3).

(Evaluation of battery performance)
The discharge capacity of the battery of Example 1 was almost the same as the discharge capacity of the lithium ion secondary battery produced using the electrolyte solution containing no crosslinkable compound A and no crosslinkable compound B. When the charge / discharge characteristics of both batteries were evaluated, the voltage of the battery of Example 1 was slightly lowered, but no deterioration in cycle characteristics was observed.
When the battery of Example 1 was disassembled in the dry box, the gel electrolyte precursor was gelled to form a gel electrolyte, and the gel electrolyte did not leak out even when the battery container was destroyed.

[Example 2]
(Method for producing gel electrolyte precursor)
Cyclohexene-3,4-dicarboxylic acid di (3,4-epoxycyclohexylmethyl) ε caprolactone modified as a crosslinkable compound A (Daicel Co., Ltd., Epolide GT-300) (represented by the formula (A-2)) Compound) and ε-caprolactone-modified 3 ′, 4′-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate as a crosslinkable compound B (Delcel, Celoxide 2081) (expressed by the above formula (B-3)) To the electrolyte solution produced in Example 1 to obtain 6% by weight to obtain a gel electrolyte precursor.

(Manufacture of lithium ion secondary batteries)
Using the gel electrolyte precursor produced above, a lithium ion secondary battery was obtained in the same manner as in Example 1.

(Evaluation of battery performance)
The discharge capacity of the battery of Example 2 was almost the same as the discharge capacity of the lithium ion secondary battery produced using the electrolyte solution that did not contain the crosslinkable compound A and the crosslinkable compound B. When the charge / discharge characteristics of both batteries were evaluated, the voltage of the battery of Example 2 was slightly lowered, but no deterioration in cycle characteristics was observed.
When the battery of Example 2 was disassembled in the dry box, the gel electrolyte precursor was gelled to form a gel electrolyte, and the gel electrolyte did not leak out even when the battery container was destroyed.

[Example 3]
(Method for producing gel electrolyte precursor)
Tetra (3,4-epoxycyclohexylmethyl) ε caprolactone modified as a crosslinkable compound A (produced by Daicel Corporation, Epolide GT-401) (compound represented by the formula (A-1)), Bis (3,4-epoxycyclohexylmethyl) adipate as crosslinkable compound B (S-28, manufactured by SINASIA) (compound represented by the above formula (B-2)) and cyclohexene as crosslinkable compound B 8 wt% of a mixture prepared by mixing oxide (manufactured by Wako Pure Chemical Industries, Ltd.) (compound represented by the above formula (B-4)) at a weight ratio of 3: 6: 1 in the electrolytic solution produced in Example 1. % To obtain a gel electrolyte precursor.

(Manufacture of lithium ion secondary batteries)
Using the gel electrolyte precursor produced above, a lithium ion secondary battery was obtained in the same manner as in Example 1.

(Evaluation of battery performance)
The discharge capacity of the battery of Example 3 was almost the same as the discharge capacity of the lithium ion secondary battery produced using the electrolyte solution containing no crosslinkable compound A and no crosslinkable compound B. When the charge / discharge characteristics of both batteries were evaluated, the voltage of the battery of Example 3 was slightly lowered, but no deterioration in cycle characteristics was observed.
When the battery of Example 3 was disassembled in the dry box, the gel electrolyte precursor was gelled to form a gel electrolyte, and the gel electrolyte did not leak out even when the battery container was destroyed.

[Comparative Example 1]
(Method for producing gel electrolyte precursor)
Electrolysis produced in Example 1 by using tetra (3,4-epoxycyclohexylmethyl) ε-caprolactone-modified (Daicel Co., Ltd., Epolide GT-401) (formula A-1) as the crosslinkable compound A The gel electrolyte precursor of Comparative Example 1 was obtained in addition to 5% by weight in the liquid.

(Manufacture of lithium ion secondary batteries)
Using the gel electrolyte precursor produced above, an attempt was made to produce a lithium secondary battery in the same manner as in Example 1. However, since the gel electrolyte precursor immediately gelled, it could not be injected into the battery cell. The battery could not be manufactured.

[Comparative Example 2]
(Method for producing gel electrolyte precursor)
Bis (3,4-epoxycyclohexylmethyl) adipate as the crosslinkable compound B (formula B-2) was added to the electrolyte solution produced in Example 1 so as to be 8% by weight. A gel electrolyte precursor was obtained.

(Manufacture of lithium ion secondary batteries)
Using the gel electrolyte precursor produced above, a lithium ion secondary battery was obtained in the same manner as in Example 1.

(Evaluation of battery performance)
The discharge capacity of the battery of Comparative Example 2 was almost the same as the discharge capacity of the lithium ion secondary battery produced using the electrolyte solution that did not contain the crosslinkable compound B. When the charge / discharge characteristics of both batteries were evaluated, the voltage of the battery of Comparative Example 2 was slightly lowered, but no deterioration in cycle characteristics was observed.
When the battery of Comparative Example 2 was disassembled in the dry box, the gel electrolyte precursor was not gelled, and when the battery container was broken, the liquid gel electrolyte precursor leaked out.

  The configurations and combinations thereof in the embodiments described above are examples, and the addition, omission, replacement, and other modifications of the configurations can be made without departing from the spirit of the present invention. Further, the present invention is not limited by each embodiment, and is limited only by the scope of the claims.

  The present invention can be widely used in the field of lithium ion secondary batteries used for portable electronic device batteries, household storage batteries, electric vehicle batteries, and the like.

Claims (9)

A non-aqueous solvent, an electrolyte,
At least one crosslinkable compound A having three or more oxirane rings;
At least one crosslinkable compound B having one or two oxirane rings,
Containing a gel electrolyte precursor. The gel electrolyte precursor according to claim 1, wherein the oxirane ring has a cyclohexene oxide group. The crosslinkable compound A contains at least one selected from the group consisting of compounds represented by the following general formula (A-1) and the following general formula (A-2). The gel electrolyte precursor described.

[In Formula (A-1), a, b, c and d each independently represents an integer of 0 to 2. In formula (A-2), a and b each independently represent an integer of 0 to 2. ] The gel electrolyte precursor according to any one of claims 1 to 3, comprising any one or more compounds selected from the following formulas (B-1) to (B-4) as the crosslinkable compound B. .

The gel electrolyte according to any one of claims 1 to 4, wherein a content ratio (A: B) of the crosslinkable compound A and the crosslinkable compound B is in a range of 95: 5 to 1:99 by weight ratio. precursor. The gel electrolyte according to any one of claims 1 to 5, wherein a total weight of the crosslinkable compound A and the crosslinkable compound B is 1 to 20 wt% with respect to a total weight of the gel electrolyte precursor. precursor. A method for producing a gel electrolyte, wherein a gel electrolyte is obtained by allowing an acid to act on the gel electrolyte precursor according to any one of claims 1 to 6 to crosslink the crosslinkable compound A and the crosslinkable compound B. . A step of injecting the gel electrolyte precursor according to any one of claims 1 to 6 into a battery container and a step of gelling the gel electrolyte precursor injected into the battery container. A method for manufacturing a secondary battery. The lithium ion secondary battery containing the gel electrolyte manufactured by the manufacturing method of Claim 7.