JP2003288940A - Nonaqueous electrolyte secondary battery and nonaqueous electrolyte - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte capable of keeping the temperature of a battery at relatively low temperatures even when short circuit between a positive electrode and a negative electrode occurs, and to provide a nonaqueous electrolyte secondary battery using the nonaqueous electrolyte. <P>SOLUTION: This nonaqueous electrolyte secondary battery 1 has a positive electrode 2, a negative electrode 3, and a nonaqueous electrolyte containing at least a solute, a liquid polyether, and a nonaqueous solvent having compatibility with the polyether. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolytic solution and a non-aqueous electrolytic solution secondary battery, and particularly to a non-aqueous electrolytic solution usable as a power source for a power storage device, an electric vehicle, an outdoor UPS and the like. The present invention relates to a technique for preventing a temperature rise of a secondary battery.

[0002]

2. Description of the Related Art With the recent increase in energy and environmental problems, development of high-performance lithium secondary batteries is urgently needed. Among various lithium secondary batteries, a lithium secondary battery using a metal oxide as a positive electrode active material and a carbon material as a negative electrode active material has recently been most widely used because of its high energy density. As the electrolyte of this conventional lithium secondary battery, a non-aqueous electrolyte solution, a solid polymer electrolyte, a gel electrolyte in which a solid polymer matrix is impregnated with a non-aqueous electrolyte solution to gel, and the like are used. Non-aqueous electrolytes and gel electrolytes generally have higher ionic conductivity than solid polymer electrolytes, and are capable of high-rate charging and discharging,
It is widely used as a power source for applications that require high discharge current. In non-aqueous electrolytes and gel electrolytes, in general, cyclic carbonates having high viscosity and high dielectric constant such as ethylene carbonate, propylene carbonate and butylene carbonate, and low viscosity and low dielectric constant such as dimethyl carbonate and diethyl carbonate are generally used. The chain carbonic acid ester shown is mixed and a solute such as LiPF _{6 is} further added for use. On the other hand, the solid polymer electrolyte is used by adding a solute such as LiPF ₆ to a polymer having lithium ion conductivity such as polyether. A lithium secondary battery using a solid polymer electrolyte is superior in safety to a non-aqueous electrolyte secondary battery because the electrolyte has high thermal stability, but
Since the ionic conductivity at room temperature is low, charging / discharging cannot be performed unless the current density is sufficiently reduced, so the application is limited in reality.

[0003]

In the conventional non-aqueous lithium secondary battery, when the positive electrode and the negative electrode of the battery are short-circuited to generate heat for some reason, the heat generated by the electrode and the electrolytic solution increases as the battery temperature rises. When the reaction is accelerated and the battery temperature further rises into a so-called thermal runaway state, the cyclic carbonate contained in the electrolyte is thermally decomposed into epoxides and carbon dioxide, and the generated epoxides explode with the positive electrode active material. There is a risk that the battery container may burst and the battery container may burst. In particular, when a lithium secondary battery is used as a power source for a power storage device or the like, it is necessary to increase the battery size in order to reduce the battery cost. Since the heat dissipation is reduced, heat easily accumulates inside the battery, and ensuring the safety of a large battery during a short circuit has been an important issue.

The present invention has been made in view of the above circumstances, and a non-aqueous electrolyte solution which can maintain the temperature of a battery at a relatively low temperature even when a short circuit occurs between the positive electrode and the negative electrode, and It is an object to provide a non-aqueous electrolyte secondary battery using this non-aqueous electrolyte.

[0005]

In order to achieve the above object, the present invention has the following constitutions. The non-aqueous electrolyte secondary battery of the present invention is characterized by comprising a non-aqueous electrolyte containing at least a solute and a liquid polyether, and a positive electrode and a negative electrode. Further, the non-aqueous electrolyte secondary battery of the present invention comprises a non-aqueous electrolyte containing at least a solute and a liquid polyether and a non-aqueous solvent compatible with the polyether, and a positive electrode and a negative electrode. It is characterized by A lithium salt is preferable as the solute. According to such a non-aqueous electrolyte secondary battery, the non-aqueous electrolyte contains a liquid polyether, and this polyether may be thermally decomposed even when the temperature inside the battery rises due to a short circuit between the positive electrode and the negative electrode. Since the temperature of the battery is not promoted, the temperature of the battery can be kept low.

The non-aqueous electrolyte secondary battery of the present invention is the non-aqueous electrolyte secondary battery described above, wherein the polyether is represented by the composition formula shown in the following [Chemical Formula 3]. It is characterized by being. However, in [Chemical Formula 3], n is in the range of 2 to 4, and m is in the range of 3 to 90.

[0007]

[Chemical 3]

Particularly, it is preferable that the polyether is one or both of polyethylene glycol and polypropylene glycol. According to the non-aqueous electrolyte secondary battery, since the above-mentioned polyether solvates with lithium ions to impart ion conductivity to the non-aqueous electrolyte, the battery characteristics of the non-aqueous electrolyte secondary battery are improved. Can be improved.

The non-aqueous electrolyte secondary battery of the present invention is the non-aqueous electrolyte secondary battery described above, wherein the polyether has an average molecular weight in the range of 400 to 4000. . The average molecular weight of the polyether is preferably in the range of 400 to 600 when the polyether is used alone, and is preferably in the range of 400 to 4000 when the polyether is used with a non-aqueous solvent. When the average molecular weight of the polyether is within the above range, the entire non-aqueous electrolyte solution becomes liquid, so that the ion conductivity of the non-aqueous electrolyte solution is improved and high rate discharge becomes possible.

The non-aqueous electrolyte secondary battery of the present invention is the non-aqueous electrolyte secondary battery described above, wherein the non-aqueous solvent is a chain carbonic acid ester. According to such a non-aqueous electrolyte secondary battery, by adding the chain carbonic acid ester, the viscosity of the non-aqueous electrolyte can be made lower than in the case of the polyether alone, and the solubility of the polyether can be increased. It is possible to improve the battery characteristics by increasing the lithium ion conductivity of the non-aqueous electrolyte.

Examples of the chain carbonic acid ester include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, ethyl butyl carbonate, dipropyl carbonate, diisopropyl carbonate and dibutyl carbonate. In addition to the chain carbonic acid ester, conventionally known solvents for non-aqueous electrolyte secondary batteries can be used as long as they are compatible with polyether. Further, in addition to the chain carbonic acid ester, a small amount of cyclic carbonic acid ester such as propylene carbonate, ethylene carbonate and butylene carbonate may be added.

Further, as the solute, LiPF ₆ ,
LiBF ₄ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO
_In addition to ₃ , LiN (C _m F _{2m + 1} SO ₂ ) (C _n F _{2n + 1} S
One or a mixture of two or more kinds of conventionally known lithium salts for non-aqueous electrolyte secondary battery solutes represented by the general formula of O ₂ ) can be used. The concentration of the solute is preferably in the range in which the lithium ion conductivity is high, and for example, the range of 0.3 to 2.0 mol / L is preferable.

The non-aqueous electrolyte secondary battery of the present invention is the non-aqueous electrolyte secondary battery described above, wherein the volume ratio of the polyether to the non-aqueous solvent is polyether: non-aqueous solvent. =
It is characterized by being in the range of 1: 9 to 1:49. According to such a non-aqueous electrolyte secondary battery, since the amount of polyether decreases, the dissociation degree of solute does not decrease and the ionic conductivity of the non-aqueous electrolyte does not decrease, and the amount of polyether increases. By doing so, the viscosity of the non-aqueous electrolyte solution is increased and the ionic conductivity is not reduced, and the battery capacity is not reduced by the side reaction, and the battery characteristics of the non-aqueous electrolyte secondary battery can be improved.

Next, the non-aqueous electrolytic solution of the present invention is characterized by comprising a solute and a liquid polyether.
Next, the non-aqueous electrolytic solution of the present invention is characterized by comprising a solute, a liquid polyether, and a non-aqueous solvent having compatibility with the polyether. The non-aqueous electrolytic solution of the present invention is the non-aqueous electrolytic solution described above, wherein the polyether is represented by the composition formula shown in [Chemical Formula 4] below. However, in [Chemical Formula 4], n is in the range of 2 to 4, and m is in the range of 3 to 90.

[0015]

[Chemical 4]

In particular, the polyether is characterized by being either one or both of polyethylene glycol and polypropylene glycol. The non-aqueous electrolytic solution of the present invention is the non-aqueous electrolytic solution described above, and is characterized in that the average molecular weight of the polyether is in the range of 400 or more and 4000 or less.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a non-aqueous electrolyte secondary battery according to an embodiment of the present invention. The non-aqueous electrolyte secondary battery 1 is of a so-called prismatic type, and has a plurality of positive electrodes (positive electrodes) 2 ... And a plurality of negative electrodes (negative electrodes) 3.
, And the separators 4 disposed between the positive electrode 2 and the negative electrode 3, respectively, and the nonaqueous electrolytic solution according to the present invention. The non-aqueous electrolyte according to the present invention contains at least a solute and a liquid polyether,
Alternatively, it contains at least a solute and a liquid polyether and a non-aqueous solvent compatible with the polyether.

The positive electrode 2, the negative electrode 3, the separator 4 and the non-aqueous electrolyte are contained in a battery case 5 made of stainless steel or the like. A sealing plate 6 is attached to the upper part of the battery case 5. A safety valve 9 for preventing an increase in the internal pressure of the battery is provided at substantially the center of the sealing plate 6. As the separator 4, a porous polymer material film such as polyethylene or polypropylene, a glass fiber, or a non-woven fabric made of various polymer fibers is used.

A positive electrode tab 12 is formed at one end of the positive electrode 2 and the positive electrode tab 12 is formed on the positive electrode tab 12a.
A positive electrode lead 12b for connecting a ... Is attached. A positive electrode terminal 7 penetrating the sealing plate 6 is attached to the positive electrode lead 12b. Similarly, the negative electrode 3 ...
Is formed at one end of the negative electrode tab 13a.
A negative electrode lead 13b for connecting the negative electrode tabs 13a is attached to the upper part of a. This negative electrode lead 13b
A negative electrode terminal 8 penetrating the sealing plate 6 is attached to the. With the above configuration, current can be taken out from the positive electrode terminal 7 and the negative electrode terminal 8.

Next, as shown in FIG. 2, the negative electrode 3 is made of Cu.
It is composed of a negative electrode collector 3a made of foil or the like, and a negative electrode film 3b formed on the negative electrode collector 3a. The aforementioned negative electrode tab 13a is formed at one end of the negative electrode current collector 3a. The negative electrode film 3b is formed, for example, by mixing a negative electrode active material powder such as graphite and a binder such as polyvinylidene fluoride. In addition, a conductive auxiliary material powder such as carbon black may be added to the negative electrode film 3b.

As the negative electrode active material, in addition to graphite, various carbon materials such as coke, amorphous carbon, graphitized carbon fiber, and a fired body of various polymer materials can be used. In addition to the carbon material, metallic lithium, lithium alloys composed of lithium and various metals, various metal oxides represented by tin, and the like can also be used. The metallic lithium or lithium alloy is not necessarily limited to powder, and may be foil-shaped. Further, as the binder of the negative electrode 3, besides polyvinylidene fluoride, polyimide or the like can be used.

Similarly, the positive electrode 2 is composed of a positive electrode current collector (current collector) 2a made of, for example, Al foil, and a positive electrode electrode film (electrode film) 2b formed on the positive electrode current collector 2a. Has been done. The positive electrode tab 12a described above is formed to project from one end of the positive electrode current collector 2a. The positive electrode film 2b is formed into a film by mixing the positive electrode active material powder, the conductive auxiliary material powder, and the binder.

The positive electrode active material powder includes, for example, lithium manganate, lithium cobalt oxide, lithium nickel oxide, lithium iron oxide, vanadium oxide, lithium vanadate, and materials obtained by substituting a part of these materials with a different element. Etc. can be used. Moreover, you may use what was conventionally known as the positive electrode active material of a nonaqueous electrolyte secondary battery.
Further, as the conductive auxiliary material powder, for example, carbonaceous materials such as carbon black, acetylene black, graphite, and carbon fiber can be used. Further, as the binder, for example, polyvinylidene fluoride, polytetrafluoroethylene,
Polyimide, SBR, CMC, etc. can be used.
Further, a conductive polymer material such as polyaniline, polypyrrole, polythiophene or polyimidazole may be added to the positive electrode film 2b. Since these conductive polymer materials are electrochemically stable and have excellent electron conductivity, they are effective in reducing the internal resistance of the positive electrode film 2b.
As the positive electrode current collector 2a, a metal foil, a metal net, an expanded metal or the like can be used, and these materials may be Al, Ti, stainless steel or the like.

Then, as shown in FIG. 2, the positive electrode layer 2b
And the negative electrode layer 3b face each other via the separator 4. In FIG. 2, the electrode films 2b and 3b are formed on one surface of each of the current collectors 2a and 3a for the sake of simplification of description. Needless to say, the films may be formed on both surfaces of the electric bodies 2a and 3a.

Next, the non-aqueous electrolyte according to the present invention contains at least a solute and a liquid polyether, or a solute and a liquid polyether, and a non-aqueous solvent having compatibility with the polyether. At least contained, and the entire electrolytic solution is liquid. That is, unlike the conventional solid polymer electrolyte or gel polymer electrolyte, the non-aqueous electrolyte solution according to the present invention does not partially contain a solid component.

The polyether acts on the lithium salt constituting the solute to solvate lithium ions, and thereby imparts lithium ion conductivity to the non-aqueous electrolyte. Furthermore, since polyether has higher heat resistance than ethylene carbonate or the like used in conventional non-aqueous electrolyte secondary batteries or polymer electrolyte secondary batteries, it is difficult to thermally decompose and the possibility of generation of decomposition gas is low. is there. Therefore, even if the positive electrode and the negative electrode are short-circuited for some reason and generate heat, the temperature inside the battery is suppressed to a low level without thermal decomposition, and an increase in internal pressure due to decomposition gas is also avoided. Further, the non-aqueous solvent is for decreasing the viscosity of the non-aqueous electrolyte and increasing the solubility of the polyether,
To improve the lithium ion conductivity of the non-aqueous electrolyte.

The above-mentioned polyether is represented by the composition formula shown in the following [Chemical formula 3], and n in the [Chemical formula 3] is in the range of 2 to 4 and m is in the range of 3 to 90. preferable. In particular, it is preferable that the polyether is one or both of polyethylene glycol and polypropylene glycol, that is, n is 1 or 2. When the composition of the polyether is within the above range, the polyether itself becomes liquid, and the polyether is solvated with lithium ions to impart ionic conductivity to the non-aqueous electrolyte.

The average molecular weight of the polyether is 400
It is preferably in the range of 4,000 or less. In particular,
When the polyether is used alone, the range of 400 to 600 is preferable, and when the polyether is used together with the non-aqueous solvent, the average molecular weight is preferably in the range of 400 or more and 4000 or less. When the polyether is used alone, the polyether itself needs to be liquid, and for that purpose, the average molecular weight needs to be in the range of 400 or more and 600 or less. When the polyether is used together with the non-aqueous solvent, even if the polyether is a solid, it may be dissolved in the non-aqueous solvent to become a liquid as a whole. For that purpose, the average molecular weight is in the range of 400 to 4000. do it. If the average molecular weight of the polyether exceeds 4000, it will not dissolve in the non-aqueous solvent, and thus the lithium salt used as the solute will not dissolve, which is not preferable. When the average molecular weight of the polyether is within the above range, the whole non-aqueous electrolyte becomes liquid, and the ionic conductivity of the non-aqueous electrolyte is improved.

The non-aqueous solvent is preferably a chain carbonic acid ester. By adding a chain ester carbonate,
The viscosity of the non-aqueous electrolyte can be lowered and the solubility of the polyether can be increased as compared with the case of using the polyether alone, whereby the lithium ion conductivity of the non-aqueous electrolyte can be increased.

Examples of the chain carbonic acid ester include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, ethyl butyl carbonate, dipropyl carbonate, diisopropyl carbonate and dibutyl carbonate. In addition to the chain carbonic acid ester, conventionally known solvents for non-aqueous electrolyte secondary batteries can be used as long as they are compatible with polyether. Further, in addition to the chain carbonic acid ester, a small amount of cyclic carbonic acid ester such as propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate and catechol carbonate may be added.

Further, as the solute, LiPF ₆ ,
LiBF ₄ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO
One or a mixture of two or more lithium salts such as ₃ , Li (CF ₃ SO ₂ ) ₂ N can be used. The concentration of the solute is preferably in the range in which the lithium ion conductivity is high, and for example, the range of 0.3 to 2.0 mol / L is preferable.

When the polyether is used as a mixture with the non-aqueous solvent, the volume ratio of the polyether to the non-aqueous solvent is preferably in the range of polyether: non-aqueous solvent = 1: 2 to 1:99. , 1: 9 to 1:49 is more preferable. When the amount of polyether is less than the above range, the solvation with lithium ions is reduced, the lithium ion concentration in the electrolytic solution is lowered, and the ionic conductivity of the non-aqueous electrolytic solution is lowered, which is not preferable. Further, if the amount of polyether exceeds the above range, the viscosity of the non-aqueous electrolytic solution increases, the ionic conductivity decreases, and deterioration due to the reductive decomposition reaction of the electrolytic solution in the negative electrode increases, which is not preferable.

According to the above non-aqueous electrolyte secondary battery, the non-aqueous electrolyte contains a liquid polyether, and this polyether heats up even when the temperature inside the battery rises due to the short circuit between the positive electrode and the negative electrode. Since there is no risk of decomposition, the temperature rise of the battery is not promoted and the battery temperature can be kept low.

[0034]

Example (Nonaqueous electrolyte secondary battery of Example) Lithium carbonate and manganese dioxide were used as starting materials for the synthesis of lithium manganate. These starting materials are sufficiently pulverized, then mixed so that Li / Mn = 1/2 (atomic ratio), and fired at 850 ° C. in an oxygen atmosphere to obtain LiMn ₂ O ₄ having an average particle size of 15 μm. A lithium manganate powder having a composition was obtained. To 90 parts by weight of this lithium manganate, 10 parts by weight of carbon black was added as a conduction aid to form a mixture, and NMP (N-methylpyrrolidone) in which polyvinylidene fluoride was dissolved in advance in this mixture.
Was mixed to form a slurry, the slurry was applied to an aluminum foil, dried, and further pressed to form a positive electrode film. In this way, the positive electrode active material is
A positive electrode having a composition of mass%, carbon black 9 mass% and polyvinylidene fluoride 9 mass% was produced.

Next, natural graphite is mixed with NMP (N-methylpyrrolidone) in which polyvinylidene fluoride is dissolved in advance to form a slurry. The slurry is applied to a copper foil, dried, and further pressed, A negative electrode film was formed. Thus, a negative electrode having a composition of 90% by mass of natural graphite and 10% by mass of polyvinylidene fluoride was produced.

By disposing a porous polypropylene separator between the positive electrode and the negative electrode, winding them spirally and storing them in a battery container, injecting an organic electrolytic solution, and then sealing. A cylindrical non-aqueous electrolyte secondary battery (Examples 1 to 15) having a diameter of 18 mm and a height of 650 mm was obtained. The non-aqueous electrolyte is polyethylene glycol (PE
LiPF ₆ was added to a mixed solvent of G) and dimethyl carbonate (DMC) so as to have a concentration of 1 mol / L. PEG has an average molecular weight of 400, 60
PE of 0, 1000, 2000, 4000
The volume ratio of G to DMC is PEG: DMC = 1: 9, 1:
19 and 1:49.

(Nonaqueous Electrolyte Secondary Battery of Comparative Example) The average molecular weight of PEG is 1000 and the concentration of LiPF ₆ is 1 mol / L.
And the composition of the non-aqueous electrolyte is PEG: DMC = 1: 2,
Comparative Example 1 as in Example 1 except that the ratio was 1:99.
And non-aqueous electrolyte secondary batteries 2 and 3 were manufactured. The composition of the non-aqueous electrolyte was PEG: DMC = 1: 9, and LiPF
The concentration of ₆ was 1 mol / L, and the average molecular weight of PEG was 20.
Non-aqueous electrolyte secondary batteries of Comparative Examples 3 and 4 were produced in the same manner as in the Example except that the amount was set to 0, 20000. Also,
As a non-aqueous electrolyte, Li is mixed with a mixed solvent of ethylene carbonate (EC) and dimethyl carbonate (DMC).
A non-aqueous electrolyte secondary battery of Comparative Example 5 was manufactured in the same manner as in Example except that PF ₆ was added to have a concentration of 1 mol / L, and the volumes of EC and DMC were measured. The ratio was EC: DMC = 1: 2.

(Measurement of Discharge Capacity) A charging / discharging cycle test was conducted on the obtained non-aqueous electrolyte secondary batteries of Examples and Comparative Examples to measure the discharge capacity at the fifth cycle. Charging is performed by constant current charging at a current of 1 / 3C until the voltage becomes 4.2V, and then constant voltage charging at 4.2V for 3 hours, and discharging is performed at a current of 1 / 3C and a voltage of 3.3V. It was decided to carry out constant current discharge until that time. The results are shown in Table 1.

(Nail Penetration Test) Further, the non-aqueous electrolyte secondary batteries of Examples and Comparative Examples were fully charged, and nails of 2 mm in diameter and 50 mm in length were driven into these batteries to conduct a nail penetration test. Then, the maximum temperature reached on the surface of the battery was measured. The results are also shown in Table 1.

[0040]

[Table 1]

(Evaluation) First, the discharge capacity is shown in Table 1.
As shown in Table 1, all of the batteries of Examples 1 to 15 showed almost the same discharge capacity as that of Comparative Example 5 (batteries using the electrolytic solution of the conventional composition), and are shown in Table 1. It can be seen that within the ranges of the volume ratio and the average molecular weight, the discharge capacity is almost the same as that of the conventional non-aqueous electrolyte secondary battery (Comparative Example 5). The average molecular weight of PEG is 1000 to 40.
Although No. 00 was solid at room temperature by itself, the whole non-aqueous electrolyte became liquid because it was dissolved in DMC. On the other hand, in Comparative Example 1, PEG: DMC is out of the optimum range, so that the viscosity of the electrolytic solution is increased and the mobility of ions is decreased, and thus the discharge capacity is considered to be decreased. Further, in Comparative Example 2, PEG: DMC is out of the optimum range, so it is considered that the ionic conductivity of the electrolytic solution is lowered and the discharge capacity is lowered. Furthermore, in Comparative Example 3, since the average molecular weight of PEG is 400 or less, the PEG on the negative electrode surface is
It is considered that the discharge reaction capacity was decreased because of the large amount of decomposition reaction of. Further, in Comparative Example 4, since the average molecular weight of PEG exceeds 4000, the solubility in DMC is reduced, and it is not possible to prepare a uniform electrolytic solution.

As for the surface temperature of the batteries when nailed, as shown in Table 1, all of the batteries of Examples 1 to 15 had a surface temperature of 100 ° C. or less. It can be seen that the battery temperature is kept low even when the positive and negative electrodes are short-circuited. On the other hand, in Comparative Example 5, the surface temperature rises to a maximum of about 330 ° C., and it is considered that a considerable amount of EC decomposition reaction has occurred. In Comparative Example 3,
The surface temperature has risen only up to about 75 ° C. This is because the concentration of PEG is lower than the optimum range and the internal resistance of the battery is high, so the battery level is kept low because the charge level is low. Seem.

As described above, the non-aqueous electrolyte secondary batteries of Examples 1 to 15 have almost the same discharge capacity as the conventional non-aqueous electrolyte secondary batteries, and the temperature at the time of nail penetration is kept low. It can be seen that it is dripping and shows excellent characteristics overall. In particular, even when the volume ratio of PEG to DMC is as low as 1: 9, the discharge characteristics and the temperature suppressing effect are good, and even when the PEG ratio is considerably low, good characteristics can be exhibited. I understand.

[0044]

As described in detail above, according to the non-aqueous electrolyte secondary battery of the present invention, the non-aqueous electrolyte contains a liquid polyether, and the polyether has high thermal stability.
Even if the positive electrode and the negative electrode are short-circuited and the temperature inside the battery rises, there is no risk of thermal decomposition, so the temperature rise of the battery is not promoted, and the temperature of the battery can be kept low.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a non-aqueous electrolyte secondary battery according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a main part of the non-aqueous electrolyte secondary battery shown in FIG.

[Explanation of symbols]

1 Non-aqueous electrolyte secondary battery 2 Positive electrode (positive electrode) 2a Positive electrode current collector 2b Positive electrode film 3 Negative electrode (negative electrode) 3a Negative electrode current collector 3b Negative electrode film 4 separator 5 battery case 6 sealing plate

Claims (11)

[Claims] 1. A non-aqueous electrolyte secondary battery comprising a non-aqueous electrolyte containing at least a solute and a liquid polyether, and a positive electrode and a negative electrode. 2. A non-aqueous electrolytic solution containing at least a solute and a liquid polyether and a non-aqueous solvent having compatibility with the polyether, and a positive electrode and a negative electrode. Water electrolyte secondary battery. 3. The non-aqueous electrolyte secondary battery according to claim 1, wherein the polyether is represented by the composition formula shown in the following [Chemical formula 1]. However, in [Chemical formula 1], n is in the range of 2 to 4, and m is 3 to 9
The range is 0. [Chemical 1] 4. The method according to claim 1, wherein the polyether is one or both of polyethylene glycol and polypropylene glycol.
The non-aqueous electrolyte secondary battery according to any one of 1. 5. The average molecular weight of the polyether is 400.
It is the above-mentioned 4000 or less range, The non-aqueous electrolyte secondary battery in any one of Claim 1 thru | or 4 characterized by the above-mentioned. 6. The non-aqueous electrolyte secondary battery according to claim 2, wherein the non-aqueous solvent is a chain carbonic acid ester. 7. The volume ratio of the polyether to the non-aqueous solvent is in the range of polyether: non-aqueous solvent = 1: 9 to 1:49, according to any one of claims 2 to 6. The non-aqueous electrolyte secondary battery according to any one of claims. 8. A nonaqueous electrolytic solution comprising a solute and a liquid polyether. 9. A non-aqueous electrolytic solution comprising a solute, a liquid polyether, and a non-aqueous solvent having compatibility with the polyether. 10. The non-aqueous electrolyte according to claim 8, wherein the polyether is represented by the composition formula shown in the following [Chemical formula 2]. However, in [Chemical Formula 2], n is in the range of 2 to 4, and m is in the range of 3 to 90. [Chemical 2] 11. The polyether has an average molecular weight of 40.
The range of 0 or more and 4000 or less is the nonaqueous electrolytic solution according to any one of claims 8 to 10.