JP2009187892A - Solid-type battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide mainly a solid-type battery capable of suppressing the deterioration of a sulfide-based solid electrolyte film due to the entry of moisture, and having high energy density. <P>SOLUTION: The solid-type battery has a totally solid-type power generation component in which a positive electrode layer, a sulfide-based solid electrolyte film, and a negative electrode layer comprised of a malleable metal having malleability are sequentially laminated, wherein a surface or an end of the sulfide-based solid electrolyte film on the side of the negative layer is covered with the negative electrode layer, and the sulfide-based solid electrolyte film is not exposed to the surface of the power generation component. The purpose is achieved by the solid-type battery. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solid-state battery that can suppress deterioration of a sulfide-based solid electrolyte membrane due to moisture intrusion and has a high energy density.

  With the rapid spread of information-related equipment and communication equipment such as personal computers, video cameras, and mobile phones in recent years, development of batteries that are used as power sources has been regarded as important. Also in the automobile industry and the like, development of high-power and high-capacity batteries for electric vehicles or hybrid vehicles is being promoted. Currently, lithium batteries are attracting attention among various batteries from the viewpoint of high energy density.

  The lithium battery currently on the market uses an organic electrolyte that uses a flammable organic solvent as a solvent. Improvement is required.

In contrast, an all-solid-state lithium battery (solid-state battery) in which the liquid electrolyte is replaced with a solid electrolyte and the battery is completely solid does not use a flammable organic solvent in the battery, thus simplifying the safety device. It is thought that it is excellent in manufacturing cost and productivity.
As such a solid battery, a battery in which a power generation element in which a positive electrode layer, a solid electrolyte, and a negative electrode layer are stacked is sealed in a battery case. Further, since the power generation element is usually one in which the end portions of the positive electrode layer and the negative electrode layer are exposed, there is a problem that a short circuit occurs due to contact between the exposed end portions of the positive electrode layer and the negative electrode layer.

In order to solve such a problem, Patent Document 1 discloses a solid-state battery in which the end portion of the positive electrode layer is covered with the solid electrolyte membrane by making the size of the solid electrolyte membrane larger than that of the positive electrode layer. According to such a method, contact between the exposed end portions can be prevented, so that short circuit can be prevented.
However, as a result, the exposed area of the solid electrolyte membrane increases, so that when the power generating element comes into contact with moisture in the air, hydrogen sulfide is generated and the performance of the sulfide-based solid electrolyte membrane is likely to deteriorate significantly. There was a problem.

On the other hand, Patent Document 2 discloses a solid battery in which a power generation element is sealed with a solid sealant made of an insulating resin.
However, the solid battery coated with such a solid sealing agent has a problem that its manufacturing process becomes complicated. In addition, due to the expansion and contraction of the power generation element accompanying charging and discharging, a crack occurs in the solid sealant, and as a result, the sulfide-based solid electrolyte membrane comes into contact with moisture in the air, generating hydrogen sulfide and sulfide-based There has been a problem that the solid electrolyte membrane is deteriorated.

JP 2000-243430 A JP-A-6-275247 Japanese Patent Laid-Open No. 9-35724

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide a solid-state battery that can suppress deterioration of the sulfide-based solid electrolyte membrane due to moisture intrusion and has a high energy density. It is what.

  In order to solve the above problems, the present invention provides an all-solid-state power generation element in which a positive electrode layer, a sulfide-based solid electrolyte membrane, and a negative electrode layer made of malleable malleable metal are laminated in this order. A surface and an end of the sulfide solid electrolyte membrane on the negative electrode layer side are covered with the negative electrode layer, and the sulfide solid electrolyte membrane is exposed on the surface of the power generation element. A solid state battery is provided.

According to the present invention, the negative electrode layer side surface and end of the sulfide solid electrolyte membrane are covered with the negative electrode layer, and the sulfide solid electrolyte membrane is not exposed on the surface of the power generation element. Thus, even when moisture is present around the power generation element, it is possible to prevent moisture and the sulfide-based solid electrolyte membrane from coming into direct contact with each other. For this reason, generation | occurrence | production of hydrogen sulfide and deterioration of a sulfide type solid electrolyte membrane can be suppressed.
In addition, the energy density can be increased by increasing the contact area between the sulfide-based solid electrolyte membrane and the negative electrode layer.
Furthermore, when the negative electrode layer is made of a malleable metal having malleability, the negative electrode layer can be excellent in stability and productivity.

  In the present invention, the power generation element is preferably immersed in a fluid sealant in a battery case that houses the power generation element. This is because the reaction between moisture in the atmosphere and the power generation element can be suppressed by being immersed in the fluid sealant. Moreover, since the said fluid sealing agent has fluidity | liquidity, even if it is a case where the volume change accompanying charging / discharging etc. arises in the said electric power generation element, it can respond to the volume change flexibly. For this reason, it is possible to eliminate the occurrence of cracks that may occur when a solid sealant is used as the sealant, and the moisture in the atmosphere and the sulfide-based solid electrolyte membrane contained in the power generation element This is because this reaction can be further suppressed. Furthermore, since it is possible to prevent the generation of cracks, it is possible to use Li, which is highly reactive with moisture in the atmosphere, as the malleable metal constituting the negative electrode layer, and the range of material selection is widened. Because. Furthermore, since the end portion of the sulfide-based solid electrolyte membrane is covered with the negative electrode layer, the reaction over time between the sulfide-based solid electrolyte membrane and the moisture contained in the fluid sealant is also improved. This is because the effects of the present invention can be more effectively exhibited.

  In the present invention, the malleable metal is preferably lithium (Li) or indium (In). This is because it is highly malleable and easy to process.

  INDUSTRIAL APPLICABILITY The present invention has an effect that it is possible to suppress deterioration of the sulfide-based solid electrolyte membrane due to moisture intrusion and to provide a solid battery having a high energy density.

  Hereinafter, the solid state battery of the present invention will be described in detail. The solid battery of the present invention is a solid battery having an all-solid-state power generation element in which a positive electrode layer, a sulfide-based solid electrolyte membrane, and a negative electrode layer made of malleable malleable metal are laminated in this order. The negative electrode layer side surface and end of the sulfide solid electrolyte membrane are covered with the negative electrode layer, and the sulfide solid electrolyte membrane is not exposed on the surface of the power generation element. It is a feature.

Such a solid battery of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of a solid state battery of the present invention. According to FIG. 1, a solid battery 10 of the present invention includes a positive electrode layer 1 containing a positive electrode active material such as LiCoO ₂ , a sulfide-based solid electrolyte membrane 2 such as Li ₂ S—P ₂ S ₅ glass ceramics, and the like. And an all-solid-state power generation element 5 having a negative electrode layer 3 made of In foil and a current collector 4 (positive electrode current collector 4a and negative electrode current collector 4b) made of SUS. Further, the entire surface of the sulfide-based solid electrolyte membrane 2 is covered with the positive electrode layer 1, the negative electrode layer 3, and the insulating ring 9 and is not exposed to the surface of the power generating element 5.
Furthermore, the power generation element 5 is housed in an open battery case 6 having a vent hole and sealed with a fluid sealant 7 made of liquid paraffin. Electricity is taken out by the takeout electrode 8 (the positive electrode side takeout electrode 8a and the negative electrode side takeout electrode 8b) connected to the positive electrode current collector 4a and the negative electrode current collector 4b.
Here, the sulfide-based solid electrolyte membrane 2 is formed so as to cover the end portion of the positive electrode layer 1, and the negative electrode layer 3 is formed so as to cover the end portion of the sulfide-based solid electrolyte membrane 2. Has been.

Here, a conventional solid battery using a sulfide-based solid electrolyte membrane will be described with reference to the drawings. As illustrated in FIG. 12, a conventional solid battery 100 includes a current collector 104 (a positive current collector 104a and a negative current collector) including a positive electrode layer 101, a sulfide-based solid electrolyte membrane 102, a negative electrode layer 103, and SUS. In general, the power generation element 105 is formed by laminating 104b), and the end of the sulfide-based solid electrolyte membrane 102 is exposed in the power generation element 105.
The power generation element 105 is usually covered with a solid sealing agent 107 made of an insulating resin. However, a crack may occur in the solid sealant 107 due to a change in the volume of the power generation element 105 due to charge and discharge. At that time, in the conventional solid battery, since the end of the sulfide solid electrolyte membrane is exposed, moisture in the atmosphere reacts with the sulfide solid electrolyte membrane to generate hydrogen sulfide. There was a problem such as.

When simply covering the end portion of the sulfide-based solid electrolyte membrane, specifically, as illustrated in FIG. 13, the side surface of the power generation element 105 in the solid-state battery 100 in FIG. When covered with the insulating frame 109 made of resin, even if a crack occurs in the solid sealant, the sulfide-based solid electrolyte membrane can be prevented from being exposed to the atmosphere. However, such an insulating frame may also be cracked due to a change in the volume of the power generation element, like the solid sealant. Further, since the insulating frame is formed, the volume that can be occupied by the power generation element is small, and as a result, there is a problem that the energy density is small. Moreover, when the said insulation frame is too hard, there existed a possibility that each structure of the electric power generation element enclosed by the said insulation frame might be broken.
Note that some of the reference numerals in FIG. 12 are the same as those in FIG.

On the other hand, according to the present invention, the negative electrode layer side surface and end of the sulfide solid electrolyte membrane are covered with the negative electrode layer, and the sulfide solid electrolyte membrane is exposed on the surface of the power generation element. Therefore, even when moisture is present around the power generation element, it is possible to prevent moisture and the sulfide-based solid electrolyte membrane from coming into direct contact with each other. For this reason, generation | occurrence | production of hydrogen sulfide and deterioration of a sulfide type solid electrolyte membrane can be suppressed.
In addition, the contact area between the sulfide-based solid electrolyte membrane and the negative electrode layer can be increased. In addition, since the end portion of the sulfide-based solid electrolyte membrane is covered with the negative electrode layer, the above-described member such as an insulating frame can be made unnecessary. As a result, the energy density can be increased.
Furthermore, the negative electrode layer is made of malleable malleable metal, so that the negative electrode layer covering the sulfide-based solid electrolyte membrane does not crack even when the volume of the power generation element changes. it can. For this reason, the said sulfide type solid electrolyte membrane shall not be exposed to the said electric power generation element surface. In addition, since the negative electrode layer can expand in the negative electrode layer side surface and end direction of the sulfide-based solid electrolyte membrane, the stress caused by the volume change associated with charge / discharge can be relaxed. Furthermore, after covering the negative electrode layer side surface and end of the sulfide-based solid electrolyte membrane with the negative electrode layer, the end can be easily covered by pressurizing with a press or the like. As a result, the stability and productivity can be improved.

The solid battery of the present invention includes at least a power generation element.
Hereafter, each structure of the solid-state battery of this invention is demonstrated in detail.

1. Power Generation Element The power generation element used in the present invention is an all-solid power generation element in which at least a positive electrode layer, a sulfide-based solid electrolyte membrane, and a negative electrode layer are laminated. Further, the sulfide-based solid electrolyte membrane is not exposed.

  Moreover, the kind of the ion conductor in the solid-state battery of the present invention is not particularly limited, but Li ion is particularly preferable. That is, the solid state battery of the present invention is preferably an all solid state lithium battery. This is because the battery can have a high energy density. Further, the solid state battery of the present invention may be a primary battery or a secondary battery, but among them, a secondary battery is preferable. For example, it is useful as a vehicle battery. Hereinafter, the material of the power generation element will be described focusing on the case of a lithium battery.

(1) Negative electrode layer The negative electrode layer which comprises the electric power generation element used for this invention is formed so that the surface and edge part by the side of the negative electrode layer of the sulfide type solid electrolyte membrane mentioned later may be covered.
Here, the end of the sulfide-based solid electrolyte membrane refers to the surface of the sulfide-based solid electrolyte membrane on the side surface of the positive electrode-sulfide-based solid electrolyte membrane laminate in which the positive electrode layer and the sulfide-based solid electrolyte membrane are laminated. It is. Specifically, as illustrated in FIG. 2, when the shape of the positive electrode layer 1 and the sulfide-based solid electrolyte membrane 2 are the same in plan view, this indicates a portion indicated by A. Further, as illustrated in FIG. 3 and FIG. 4, when the plan view shape of the sulfide-based solid electrolyte membrane 2 is larger than that of the positive electrode layer 1, the portion indicated by A is meant.
Further, as illustrated in FIG. 5, the shape of the negative electrode layer is also formed on the surface of the sulfide-based solid electrolyte membrane 2 on the positive electrode layer 1 side within a range in which a short circuit with the positive electrode layer 1 described later does not occur. It may be.
In addition, about the code | symbol in FIGS. 2-5, it is the same as the code | symbol in FIG.

The negative electrode layer used in the present invention is malleable and may be made of a malleable metal which is a metal used as a negative electrode active material contained in the negative electrode layer in a general solid battery. Specific examples of such malleable metals include Li, In, Al, Si, and Sn. Moreover, Li alloy can also be used.
In the present invention, Li or In is particularly preferable, and In is particularly preferable. This is because Li and In are excellent in malleability and easy to process.
In addition, since In has a low reactivity with moisture, deterioration of the negative electrode layer can be prevented even when moisture is present around the power generation element. Therefore, the power generation element can be made more stable. In addition, a hydrophilic fluid sealant can be used as the sealant, and the range of material selection can be widened.

Further, the negative electrode layer used in the present invention may be a metal film of the malleable metal, or may be a product obtained by compression molding the powder of the malleable metal. Specific examples of the metal film of the malleable metal include the metal foil, the plating foil, and the vapor deposition foil of the malleable metal, and among them, the metal foil is preferable. This is because the surface and end of the sulfide solid electrolyte membrane on the negative electrode layer side can be easily covered by pressing together with the positive electrode and sulfide solid electrolyte membrane described later.
Further, when the negative electrode layer is formed by compression molding the malleable metal powder, a conductive material may be added in order to improve conductivity. Examples of the conductive material include acetylene black and carbon fiber.

It is preferable that the negative electrode layer used in the present invention has a water repellent treatment on the exposed surface of the power generating element. This is because the water-repellent treatment can more effectively prevent contact between the sulfide-based solid electrolyte membrane described later and moisture.
Here, examples of the water repellent treatment include coating such as dip coating and spin coating, and a printing method.

  Although it does not specifically limit as a film thickness of the said negative electrode layer, Usually, it exists in the range of 1 micrometer-100 micrometers. The negative electrode layer usually has a negative electrode current collector that collects current from the negative electrode layer. Examples of the material of the negative electrode current collector include stainless steel (SUS), and examples of the shape of the negative electrode current collector include a foil shape and a mesh shape.

(2) Sulfide-based solid electrolyte membrane The sulfide-based solid electrolyte membrane constituting the power generation element used in the present invention has its negative electrode layer side and end covered with the aforementioned negative electrode layer. Further, it is not exposed on the surface of the power generating element.

The shape of the sulfide-based solid electrolyte membrane used in the present invention may be any shape that can have a desired energy density without causing a short circuit. Specifically, the shape in plan view may be wider than the positive electrode layer described later as illustrated in FIGS. 3 and 4 described above, or the same as illustrated in FIG. 2 described above. It may be.
In particular, in the present invention, it is preferable that the sulfide-based solid electrolyte membrane has a wider shape in plan view than a positive electrode layer described later. In particular, as shown in FIG. A shape that covers the side surface is preferred. This is because the energy density can be increased. Moreover, it is because the short circuit of a positive electrode and a negative electrode can be prevented effectively.

The sulfide-based solid electrolyte constituting the sulfide-based solid electrolyte membrane used in the present invention is not particularly limited as long as it contains a sulfur component and has ionic conductivity, and is usually in the air. It reacts with moisture to generate hydrogen sulfide.
Specific examples of such a sulfide-based solid electrolyte include those having Li, S, and a third component. Examples of the third component include at least one selected from the group consisting of P, Ge, B, Si, I, Al, Ga, and As. Specific examples of the sulfide-based solid electrolyte include Li ₂ S—P ₂ S ₅ , 70Li ₂ S-30P ₂ S ₅ , 80Li ₂ S-20P ₂ S ₅ , Li ₂ S—SiS ₂ , LiGe _0. mention may be made of ₂₅ P _0.75 S _4. of these _Li 2 _S-P 2 _{S 5} is preferred. This is because a solid electrolyte membrane having high ionic conductivity can be obtained.

  Examples of the method for producing the sulfide-based solid electrolyte include a method of vitrifying a raw material containing Li, S, and a third component by a planetary ball mill, or a method of vitrifying by melting and quenching. be able to. In the production of the sulfide-based solid electrolyte, heat treatment may be performed for the purpose of improving performance. Examples of the method for forming the sulfide solid electrolyte into a film include a method of pelletizing the sulfide solid electrolyte by uniaxial compression molding.

  Further, the film thickness of the sulfide-based solid electrolyte film may be any film that can have a desired energy density without short-circuiting, and is, for example, in the range of 0.1 μm to 1000 μm. It is preferable to be within the range of 1 μm to 300 μm.

(3) Positive electrode layer The positive electrode layer which comprises the electric power generation element used for this invention can use the thing similar to the positive electrode layer used for a general solid battery. The positive electrode layer has at least a positive electrode active material. Examples of the positive electrode active material include LiCoO ₂ , LiMnO ₂ , Li ₂ NiMn ₃ O ₈ , LiVO ₂ , LiCrO ₂ , LiFePO ₄ , LiCoPO ₄ , LiNiO ₂ , LiNi _1/3 Co _1/3 Mn _1/3 O. _{2 and the} like, and LiCoO ₂ is particularly preferable. The positive electrode layer may contain a conductive material in order to improve conductivity. Examples of the conductive material include acetylene black and carbon fiber.

  Although it does not specifically limit as a film thickness of the said positive electrode layer, Usually, it exists in the range of 1 micrometer-100 micrometers. Moreover, as a formation method of the said positive electrode layer, the method of compression-molding powder, such as said positive electrode active material, etc. can be mentioned, for example.

  The positive electrode layer used in the present invention usually has a positive electrode current collector that collects current from the positive electrode layer. Examples of the material of the positive electrode current collector include SUS, and examples of the shape of the positive electrode current collector include a foil shape and a mesh shape.

(4) Power generation element The power generation element used in the present invention only needs to have at least a positive electrode layer, a sulfide-based solid electrolyte membrane, and a negative electrode layer laminated, and if necessary, has an insulating ring. There may be. This is because the positive electrode layer and the negative electrode layer can be prevented from being short-circuited. Moreover, it is for the said sulfide type solid electrolyte membrane not to be exposed to the surface of the said electric power generation element.
The shape of such an insulating ring may be any shape as long as there is little risk of cracking due to volume change associated with charging / discharging, and the energy density does not significantly decrease. Specifically, FIG. As shown in FIG. 3, the positive electrode layer is formed so as to cover the side surface of the positive electrode current collector, or as shown in FIG. 5, it is formed so as to cover the inner wall of the negative electrode layer. be able to.
In addition, the insulating ring material may be any material as long as it has insulating properties, and examples thereof include general insulating resins.

2. Solid-state battery The solid-state battery of the present invention is not limited as long as it has the power generation element, but usually has a take-out electrode connected to each of the current collectors.
Moreover, you may have an intermediate electrical power collector as needed. Further, the power generation element may be housed in a battery case that houses the power generation element, and the periphery may be surrounded by a sealing agent in the battery case.
Further, when the sealant is a fluid sealant having fluidity, it may have a stirring means, a temperature adjusting means, a guide means, a dehydrating means, and the like.

(1) Extraction electrode Examples of the shape of the extraction electrode include a foil shape and a lead shape. Moreover, as a material of the said extraction electrode, the material generally used for a solid battery can be used, Specifically, stainless steel (SUS) etc. can be mentioned.

(2) Sealant Since the periphery is surrounded by the sealing material, the reaction between the sulfide-based solid electrolyte membrane in the power generation element and moisture in the atmosphere can be suppressed.
Such a sealant is preferably a fluid sealant having fluidity. This is because, since it has fluidity, it can flexibly cope with the volume change even when the volume change of the power generation element caused by charging / discharging occurs. For this reason, it is possible to eliminate the occurrence of cracks that may occur when a solid sealant is used as the sealant, and the moisture in the atmosphere and the sulfide-based solid electrolyte membrane contained in the power generation element This is because this reaction can be further suppressed. Further, since it is possible to prevent the generation of cracks, it is possible to use Li, which is highly reactive with moisture in the atmosphere, as the malleable metal constituting the negative electrode layer, and the range of material selection is widened. Because. Furthermore, since the end of the sulfide-based solid electrolyte membrane is covered with the negative electrode layer, the reaction over time between the sulfide-based solid electrolyte membrane and moisture contained in the fluid sealant is also suppressed. Therefore, the effect of the present invention can be exhibited more effectively.

Any fluid sealing agent may be used as long as it has the property of sealing the power generation element in the battery case and not reacting with the sulfide-based solid electrolyte membrane. In the present invention, “does not react with the sulfide-based solid electrolyte membrane” means that hydrogen sulfide or the like is not generated by the reaction with the sulfide-based solid electrolyte membrane, and the function of the sulfide-based solid electrolyte membrane is not substantially deteriorated. That means. The fluid sealant used in the present invention has fluidity. “Having fluidity” means that it is not solid or gas, and means that it can flexibly follow the volume change of the power generation element accompanying charging and discharging. Accordingly, the fluid sealant in the present invention includes a dispersion system such as a sol, a gel, and an emulsion in addition to a normal liquid (organic solvent). Moreover, the material excellent in insulation is normally used for the fluid sealing agent in this invention.
Hereinafter, the fluid sealant used in the present invention will be described separately for a case where the battery case is an open type and a case where the battery case is a sealed type.

(I) When the battery case is an open type When the battery case is an open type, as shown in FIG. 1 described above, the fluid sealant comes into contact with the atmosphere (air). Therefore, it is preferable that the fluid sealant has high hydrophobicity. More specifically, the fluid sealant is preferably a hydrophobic liquid. This is because moisture in the air can be prevented from coming into contact with the sulfide-based solid electrolyte membrane.

  In the present invention, the amount of water contained in the fluid sealant is preferably small. Specifically, it is preferably 100 ppm or less, particularly 50 ppm or less, particularly preferably 30 ppm or less. This is because if the amount of water contained in the fluid sealant is too large, the sulfide-based solid electrolyte membrane is likely to deteriorate.

The solubility of the fluid sealant in water (water vapor) is, for example, 1% (w / w) or less, particularly 0.5% (w / w) or less, particularly 0 at 25 ° C. and 1 atm. .1% (w / w) or less is preferable. In general, as an index representing the hydrophobicity of an object, there is a method of evaluation using a partition coefficient of a fluid sealant with respect to a mixed solvent of n-octanol and water. In the present invention, LogP _ow of flowable sealant, for example 0 or more and preferably 1 or more, and particularly preferably 2 or more.

  Examples of the hydrophobic liquid include chain saturated hydrocarbons, cyclic saturated hydrocarbons, and nonpolar liquids.

  As long as the chain saturated hydrocarbon has fluidity, it may have a straight chain structure or a branched structure. Furthermore, the fluid sealant may be a single chain saturated hydrocarbon or a mixture of a plurality of chain saturated hydrocarbons as long as it has fluidity.

  Examples of the simple chain saturated hydrocarbon include pentane, hexane, heptane, octane, nonane, decane, undecane, and dodecane. On the other hand, examples of the mixture of a plurality of chain saturated hydrocarbons include liquid paraffin. Liquid paraffin generally refers to a mixture of chain saturated hydrocarbons having 20 or more carbon atoms and liquid at room temperature. In the present invention, the hydrophobic liquid is preferably liquid paraffin.

Specific examples of the cyclic saturated hydrocarbon include cycloalkanes. Examples of the cycloalkane include cyclopentane, cyclohexane, cycloheptane, and cyclooctane.
Examples of the nonpolar liquid include benzene, toluene, diethyl ether, chloroform, ethyl acetate, tetrahydrofuran, and methyl chloride.
In the present invention, a dispersible fluid sealant such as a sol, gel, or emulsion can also be used.

(Ii) When the battery case is a sealed type When the battery case is a sealed type, the fluid sealant basically does not contact the atmosphere (air). Therefore, the kind of fluid sealant is not particularly limited as long as it has a property that does not react with the sulfide-based solid electrolyte membrane. Among them, in the present invention, it is preferable that the fluid sealant has high hydrophobicity, and more specifically, the fluid sealant is preferably a hydrophobic liquid. For example, even if air remains in the positive electrode layer or the like, it can be easily removed, and moisture can be prevented from coming into contact with the sulfide-based solid electrolyte membrane. In addition, since the kind etc. of hydrophobic liquid are the same as the content mentioned above, description here is abbreviate | omitted.

(3) Battery case As said battery case, what can hold | maintain the said electric power generation element and the sealing agent surrounding the said electric power generation element should just be hold | maintained. Such a battery case may be an open battery case that allows contact between the atmosphere and the sealant, or may be a sealed battery case that cannot be contacted. Used.

When the battery case is an open-type battery case, there is an advantage that a sudden change in internal pressure can be alleviated even when the volume of the power generation element is changed due to charging / discharging or the like. As a solid battery having such an open battery case, specifically, as shown in FIG. 1 described above, a solid battery having a battery case 6 having a vent can be mentioned.
In addition, the diameter of the vent hole in the solid battery using the open battery case is not particularly limited as long as the rapid change in the internal pressure can be reduced, but the diameter of the vent hole is preferably small. This is because when a fluid sealant is used as the sealant, volatilization of the fluid sealant can be suppressed.

Further, when the battery case is a sealed battery case, it is possible to prevent moisture in the air from entering the inside of the battery and further to prevent volatilization of the fluid sealant. Have. Specific examples of the solid battery having such a sealed battery case include those shown in FIG.
Moreover, it is preferable that the solid battery using the sealed battery case further has an internal pressure adjusting means. This is because even if the volume change of the power generation element accompanying charging / discharging or the like occurs, a sudden change in internal pressure can be alleviated.

  Specific examples of the internal pressure adjusting means include means using a partition plate 11 and a spring 12 as shown in FIG. For example, when the power generation element expands, the partition plate 11 is pushed by the fluid sealant 7 and the spring 12 is contracted, so that a sudden increase in internal pressure is alleviated. On the other hand, when the power generation element contracts, the spring 12 is extended, and the partition plate 11 pushes the fluid sealant 7, so that the rapid decrease in internal pressure is alleviated. On the other hand, as shown in FIG. 7B, an inert gas 13 containing no moisture is enclosed in a sealed battery case 6 and the internal pressure is adjusted via the inert gas 13. good. In this case, since the fluid sealant does not come into contact with the internal pressure adjusting means, there is an advantage that contamination of the fluid sealant can be prevented. As another internal pressure adjusting means, for example, a means for providing a resin balloon or the like instead of the partition plate and the spring, and a means for using a stretchable material for the battery case itself can be cited.

  In the present invention, the battery case may be one in which a take-out electrode is incorporated in part. This is because leakage of the fluid sealant can be prevented. Specifically, as shown in FIG. 8, the battery case 6 may include a part in which extraction electrodes 8a and 8b are incorporated. In the solid-state battery as shown in FIG. 6 described above, the extraction electrodes 8a and 8b are disposed so as to penetrate the battery case 6. Therefore, even if the penetration portion is sealed with resin or the like, due to deterioration of the resin or the like, There is a possibility that the fluid sealant may leak from the penetration portion. On the other hand, in the solid battery as shown in FIG. 8, since the sealing of the penetrating portion is unnecessary, the leakage of the fluid sealant can be surely prevented.

(4) Intermediate current collector In the present invention, it is preferable that a plurality of the power generation elements are stacked via the intermediate current collector. This is because a more practical solid-state battery can be obtained. Specifically, as shown in FIG. 9, a plurality of power generation elements in which the positive electrode layer 1, the sulfide-based solid electrolyte membrane 2 and the negative electrode layer 3 are stacked in this order are stacked via an intermediate current collector 4c. A solid structure battery having a bipolar structure can be given. In this case, the number of stacked power generation elements is, for example, preferably 1 or more, more preferably 2 or more, further preferably 10 or more, and particularly preferably 50 or more. On the other hand, the number of power generation elements to be stacked is usually 100 or less.

(5) Stirring means The solid state battery of the present invention preferably has a stirring means for stirring the fluid sealing agent. This is because, for example, when the power generating element is heated or cooled via the fluid sealant, the temperature can be easily uniformed. Since the conventional sealing agent uses a solid sealing agent made of a solid resin or the like that does not have fluidity, even if the power generating element is heated or cooled via the sealing agent, the temperature is uneven. There was a problem. On the other hand, in the present invention, by stirring the fluid sealant, the temperature of the power generation element can be adjusted uniformly, and the power generation efficiency can be improved.

  The stirring means is not particularly limited as long as it can stir the fluid sealant. For example, a means for circulating the fluid sealant through an external path connected to the battery case, etc. Can be mentioned. Specifically, as shown in FIG. 10, a means for circulating the fluid sealing agent 7 through an external path 13 connected to the battery case 6 can be exemplified. In the present invention, liquid circulation means (for example, a motor or the like) for circulating the fluid sealant may be disposed in the external path 13. In the solid battery shown in FIG. 10, the fluid sealant 7 inside the battery case 6 is heated and raised by the power generation element, and conversely, the fluid sealant 7 inside the external path 13. Falls by natural cooling. Therefore, it is possible to gently circulate the fluid sealant using the difference in specific gravity without providing any liquid circulation means. Another example of the stirring means is a means for installing a screw or the like inside the battery case.

(6) Temperature adjusting means The solid state battery of the present invention preferably has temperature adjusting means for heating or cooling the fluid sealant. This is because, by adjusting the temperature of the power generation element via the fluid sealant, charging / discharging and the like can be performed under optimal temperature conditions, and power generation efficiency can be improved. Further, since the fluid sealant is in direct contact with the power generation element, it has an advantage that the temperature of the power generation element can be adjusted efficiently. As a method for heating / cooling the fluid sealant, for example, a method for heating / cooling the fluid sealant via a battery case, a temperature adjusting tube is installed inside the battery case, Examples thereof include a method of heating / cooling the fluid sealant through a medium / refrigerant and a method of heating / cooling the fluid sealant through the external path described above. In the case of an in-vehicle solid battery, the fluid sealant may be cooled through a radiator, for example. In particular, the solid-state battery of the present invention preferably has a temperature adjusting means and the above-described stirring means. It is because the advantage using the sealing agent which has fluidity | liquidity can fully be utilized.

(7) Guide means In the present invention, it is preferable that the power generation element has guide means for letting out air bubbles on the bottom surface side of the battery case. This is because by providing the guide means, it is possible to prevent bubbles from remaining near the bottom surface of the battery case when the power generation element is immersed in the fluid sealant. Specifically, as shown in FIG. 11, the power generation element 5 may have a guide means 14 on the bottom surface side of the battery case 6 via the extraction electrode 8 b. Thereby, it is possible to suppress the bubbles 15 from remaining near the bottom surface of the battery case 6. Examples of the guide means shape include an inverted triangle. Further, a groove may be formed on the surface of the current collector or extraction electrode to serve as guide means.

(8) Dehydrating means The solid-state battery of the present invention may have a dehydrating means for reducing the water content of the fluid sealant. By providing the dehydrating means, it is possible to further prevent deterioration of the sulfide-based solid electrolyte membrane. Examples of the dehydrating means include a method of disposing a dehydrating agent inside the battery case. The dehydrating agent is not particularly limited as long as it has water absorption and does not adversely affect the fluid sealant, and a general dehydrating agent can be used. Specific examples include silica gel and molecular sieve.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be described more specifically with reference to examples.

[Example 1]
A power generation element was produced in an inert gas atmosphere. First, LiCoO ₂ was prepared as a positive electrode active material, and In foil (thickness: 100 μm) was prepared as a negative electrode active material. Next, Li ₂ S (manufactured by Nippon Kagaku Kogyo) and P ₂ S ₅ (manufactured by Aldrich) were pulverized and mixed with a planetary ball mill to form Li ₂ S—P ₂ S ₅ as a sulfide-based solid electrolyte. . Subsequently, a positive electrode and a negative electrode current collector (stainless steel (SUS), thickness 10 mm) were prepared, and the side surfaces thereof were covered with an insulating ring made of polycarbonate having a thickness of 10 mm.
Next, a positive electrode current collector (SUS, thickness 10 mm), a positive electrode active material (LiCoO ₂ ), and a sulfide-based solid electrolyte (Li ₂ S—P ₂ S ₅ ) whose side surfaces are covered with an insulating ring in this order. The resulting laminate was pressed with a uniaxial press at 5.1 t / cm ² to obtain a laminate of positive electrode current collector / positive electrode layer / sulfide-based solid electrolyte membrane laminated as shown in FIG.
Next, the laminate of the positive electrode current collector / positive electrode layer / sulfide-based solid electrolyte membrane was covered with the In foil from the sulfide-based solid electrolyte membrane side, and 0.64 t / cm ^{2 with} a uniaxial press. As shown in FIG. 1, a laminate of positive electrode current collector / positive electrode layer / sulfide-based solid electrolyte membrane / negative electrode layer was obtained. Furthermore, a current collector (SUS, thickness 10 mm) was attached to the negative electrode layer of the laminate, thereby obtaining a power generation element.
From the above, an all-solid-state power generation element in which the sulfide-based solid electrolyte membrane was not exposed on the surface was produced.

  Next, in an inert gas atmosphere, 600 mL of liquid paraffin (water content of about 100 ppm) is placed in a 2 L desiccator, and after the above power generation element is completely immersed, the desiccator cock is opened, and the inside of the desiccator is in the atmosphere. The cock was closed. In this way, a solid state battery having an all solid state power generation element in which the sulfide-based solid electrolyte membrane was not exposed on the surface was obtained.

[Example 2]
A solid-state battery in which the sulfide-based solid electrolyte membrane was not exposed on the surface of the power generating element was obtained in the same manner as in Example 1 except that Li foil was used as the negative electrode active material.

It is a schematic sectional drawing which shows an example of the solid battery of this invention. It is a schematic sectional drawing which shows an example of the electric power generation element used for this invention. It is a schematic sectional drawing which shows the other example of the electric power generation element used for this invention. It is a schematic sectional drawing which shows the other example of the electric power generation element used for this invention. It is a schematic sectional drawing which shows the other example of the electric power generation element used for this invention. It is a schematic sectional drawing which shows the other example of the solid battery of this invention. It is a schematic sectional drawing which shows the other example of the solid battery of this invention. It is a schematic sectional drawing which shows the other example of the solid battery of this invention. It is a schematic sectional drawing which shows the other example of the solid battery of this invention. It is a schematic sectional drawing which shows the other example of the solid battery of this invention. It is a schematic sectional drawing which shows the other example of the solid battery of this invention. It is a schematic sectional drawing which shows an example of the conventional solid battery. It is a schematic sectional drawing which shows the other example of the conventional solid battery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 ... Positive electrode layer 2,102 ... Sulfide type solid electrolyte membrane 3, 103 ... Negative electrode layer 4, 104 ... Current collector 5, 105 ... Power generation element 6 ... Battery case 7, 107 ... Sealing agent 8 ... Extraction electrode 10, 100 ... Solid battery

Claims (3)

A solid state battery having an all-solid-state power generation element in which a positive electrode layer, a sulfide-based solid electrolyte membrane, and a negative electrode layer made of malleable malleable metal are laminated in this order,
A solid type wherein the surface and end of the sulfide-based solid electrolyte membrane on the negative electrode layer side are covered with the negative electrode layer, and the sulfide-based solid electrolyte membrane is not exposed on the surface of the power generation element battery.   The solid state battery according to claim 1, wherein the power generation element is immersed in a fluid sealant in a battery case that houses the power generation element.   The solid-state battery according to claim 1 or 2, wherein the malleable metal is lithium or indium.

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