JP7750697B2 - battery - Google Patents

Description

The present invention relates to a battery in which a power generating element is housed in an exterior material.

Patent Document 1 discloses prior art related to batteries, in which a power generating element consisting of a laminated positive electrode, electrolyte layer, and negative electrode is housed in an exterior material.

JP 2015-95330 A

In the prior art, the power generating element housed in the exterior material is easily affected by the temperature around the exterior material, so when the ambient temperature drops, the temperature of the power generating element also drops, resulting in a decrease in battery performance. Furthermore, vibrations and mechanical shocks are easily transmitted to the power generating element, making it susceptible to damage.

The present invention was made to solve this problem, and aims to provide a battery whose power generating element is less susceptible to the effects of vibration, mechanical shock, and ambient temperature.

To achieve this objective, the battery of the present invention comprises a power generating element formed by stacking a positive electrode, a solid electrolyte layer, and a negative electrode, and an exterior material that houses the power generating element, with heat insulating materials disposed between the power generating element and the exterior material on both sides of the stacking direction of the power generating element.

In the battery of the present invention, a power generating element, which is made up of a stack of a positive electrode, a solid electrolyte layer, and a negative electrode, is housed in an exterior material. The area of the power generating element as viewed in the stacking direction is larger than the area of the power generating element as viewed in a direction perpendicular to the stacking direction. Therefore, by placing insulating materials between the power generating element and the exterior material on both sides of the stacking direction of the power generating element, which has a large influence on heat transfer, the ambient temperature of the exterior material is less likely to affect the power generating element. Furthermore, the insulating materials placed on both sides of the power generating element in the stacking direction buffer vibrations and mechanical shocks, making it less likely that vibrations and mechanical shocks will be transmitted to the power generating element.

FIG. 1 is a perspective view of a battery according to a first embodiment. FIG. 2A is a cross-sectional view of a battery according to a first embodiment, and FIG. 2B is a cross-sectional view of a battery according to a second embodiment. FIG. 10 is an exploded three-dimensional view of a battery according to a third embodiment. 10A is a cross-sectional view of a battery according to a third embodiment, and FIG. 10B is a cross-sectional view of a battery according to a fourth embodiment. 10A is a cross-sectional view of a battery according to a fifth embodiment, and FIG. 10B is a cross-sectional view of a battery according to a sixth embodiment. 10A is a cross-sectional view of a battery according to a seventh embodiment, and FIG. 10B is a cross-sectional view of a battery according to an eighth embodiment.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. A battery 10 according to a first embodiment will be described with reference to Figures 1 and 2(a). Figure 1 is a perspective view of the battery 10.

Battery 10 has a power generating element 14 housed in an exterior material 11. Battery 10 is a solid-state battery in which the power generating element 14 is made of a solid. "The power generating element 14 is made of a solid" means that the skeleton of the power generating element 14 is made of a solid, and does not exclude, for example, a structure in which the skeleton is impregnated with a liquid. In this embodiment, the battery 10 is described as a lithium-ion battery. In all drawings, the thicknesses of objects such as the exterior material 11 and the power generating element 14 are shown exaggerated.

The exterior material 11 includes a storage section 12 that creates an internal space 11a (see Figure 2(a)), and a sealing section 13 that seals the internal space 11a created by the storage section 12. In this embodiment, the sealing section 13 is provided on three sides of the exterior material 11. The terminals 22, 23 provided on the power-generating element 14 intersect with a part of the sealing section 13 and are extended to the outside of the exterior material 11. The sealing section 13 reduces the intrusion of moisture into the internal space 11a created by the exterior material 11, thereby reducing performance degradation of the power-generating element 14.

The exterior material 11 includes, for example, a surface layer, a barrier layer, and an adhesive layer (none of which are shown), in that order. The surface layer is made of, for example, a polyester resin such as polyethylene terephthalate, or polyimide. The barrier layer is made of, for example, a metal foil such as aluminum, or a vapor-deposited layer. The adhesive layer is made of, for example, an olefin resin such as polyethylene, polypropylene, or an ethylene-propylene-based copolymer. The exterior material 11 may have other layers, multiple barrier layers, or the surface layer may be omitted, as necessary. The seal portion 13 is created by welding the adhesive layer of the exterior material 11.

2(a) is a cross-sectional view of the battery 10 cut at the terminal 23. The power generating element 14 is disposed in the internal space 11a formed by the exterior material 11. The internal space 11a is depressurized when the seal portion 13 is formed and the exterior material 11 is sealed, so the air pressure in the internal space 11a is lower than atmospheric pressure. The air pressure in the internal space 11a needs to be lower than atmospheric pressure, but it may also be a medium vacuum, high vacuum, or ultra-high vacuum of 10 ² Pa or less.

The power generating element 14 includes, in order, a positive electrode 15, a solid electrolyte layer 18, and a negative electrode 19. The power generating element 14 is formed by stacking the positive electrode 15, the solid electrolyte layer 18, and the negative electrode 19. In this embodiment, the power generating element 14 has a rectangular plate shape when viewed from the stacking direction of the power generating element 14 (the vertical direction in Figure 2(a)). However, there are no restrictions on the shapes of the positive electrode 15, the solid electrolyte layer 18, and the negative electrode 19.

The positive electrode 15 is composed of a current collector 16 and an active material layer 17 stacked together. The current collector 16 is a conductive member. Examples of materials for the current collector 16 include metals selected from Ni, Ti, Fe, and Al, alloys containing two or more of these elements, stainless steel, and carbon materials. A terminal 23 is connected to the current collector 16.

The active material layer 17 contains an active material. Examples of the active material include a metal oxide containing a transition metal. Examples of the metal oxide containing a transition metal include an oxide containing Li and one or more elements selected from Mn, Co, Ni, Fe, Cr _, and V. Examples of the _metal oxide containing a transition metal include LiCoO2, _{LiNi0.8Co0.15Al0.05O2 , LiMn2O4 , LiNiVO4 , LiNi0.5Mn1.5O4} , LiNi1 _{/ 3Mn1 / 3Co1 / 3O4 ,} and _LiFePO4 .

To reduce the resistance of the active material layer 17, the active material layer 17 may contain a conductive additive. Examples of conductive additives include carbon black, acetylene black, ketjen black, carbon fiber, Ni, Pt, and Ag. To increase the ionic conductivity of the active material layer 17, the active material layer 17 may contain a solid electrolyte (described below) or an electrolytic solution.

The solid electrolyte layer 18 contains a solid electrolyte. The solid electrolyte includes one or more solid electrolytes selected from oxides, sulfides, hydrides, and organic compounds. The solid electrolyte layer 18 may also contain an electrolytic solution.

Examples of oxide-based solid electrolytes include oxides having a NASICON structure, oxides having a perovskite structure, and oxides having a garnet structure. Oxides having a NASICON structure include oxides containing at least Li, M (where M is one or more elements selected from Ti, Zr, and Ge), and P, such as Li(Al,Ti) ₂ ( _PO4 ) ₃ and Li(Al,Ge) ₂ ( _{PO4 )3 .} Oxides having a perovskite structure include oxides containing at least Li, Ti, and La, such as La2 _{/3-xLi3xTiO3 .}

Examples of sulfide-based solid electrolytes include glass and glass ceramics such as crystalline thiolithium type, Li ₁₀ GeP ₂ S ₁₂ type, argyrodite type, Li ₇ P ₃ S ₁₁ type, and Li ₂ S-P ₂ S _5. Examples of hydride-based solid electrolytes include solid solutions of LiBH ₄ with lithium halide compounds (LiI, LiBr, LiCl) and lithium amide (LiNH ₂ ). Examples of organic compound-based solid electrolytes include polyethylene oxide, polypropylene oxide, and polyacrylnitrile.

The negative electrode 19 is composed of a current collector 20 and an active material layer 21 stacked together. The current collector 20 is a conductive member. Examples of materials for the current collector 20 include metals selected from Ni, Ti, Fe, Cu, and Si, alloys containing two or more of these elements, stainless steel, and carbon materials. A terminal 22 (see Figure 1) is connected to the current collector 20.

The active material layer 21 contains an active material, which can be exemplified by Li, a Li—Al alloy, Li ₄ Ti ₅ O ₁₂ , graphite, In, Si, Sn, a Si—Li alloy, a Sn—Li alloy, and an oxide containing Si.

To reduce the resistance of the active material layer 21, the active material layer 21 may contain a conductive additive. Examples of conductive additives include carbon black, acetylene black, ketjen black, carbon fiber, Ni, Pt, and Ag. To increase the ionic conductivity of the active material layer 21, the active material layer 21 may contain a solid electrolyte or an electrolytic solution.

In the battery 10, thermal insulators 24, 27 are disposed between the power generating element 14 and the exterior material 11 on both sides of the power generating element 14 in the stacking direction. The thermal insulators 24, 27 are fixed to the power generating element 14 by the exterior material 11. To ensure sufficient thermal insulation, the thermal insulators 24, 27 preferably have a thermal conductivity of 0.1 W/m·K or less. Examples of the thermal insulators 24, 27 include porous bodies made of synthetic resins such as polystyrene, polyethylene, and urethane; porous bodies made of inorganic materials such as silica; porous bodies made of rubber; and glass wool.

The insulating material 24 is disposed between the positive electrode 15 and the exterior material 11. The size of the insulating material 24 is larger than that of the positive electrode 15. The insulating material 24 comprises a first portion 25 that contacts the entire surface of the power generating element 14 facing the stacking direction, and a second portion 26 that is positioned around the first portion 25. The second portion 26 has a notch at a position corresponding to the connection between the current collector 16 and the terminal 23. The portion of the second portion 26 other than the notch contacts the side surface of the power generating element 14.

The insulating material 27 is disposed between the negative electrode 19 and the exterior material 11. The size of the insulating material 27 is larger than that of the negative electrode 19. The insulating material 27 comprises a first portion 28 that contacts the entire surface of the power generating element 14 facing the stacking direction, and a second portion 29 that is positioned around the first portion 28. The second portion 29 has a notch at a position corresponding to the connection between the current collector 20 and the terminal 22. The portion of the second portion 29 other than the notch contacts the side of the power generating element 14.

The area of the power generating element 14 as viewed in the stacking direction is larger than the area of the power generating element 14 as viewed in a direction perpendicular to the stacking direction. When there is a temperature difference, the amount of heat transfer from an object is proportional to the area of the object. Therefore, by placing insulating materials 24, 27 between the power generating element 14 and the exterior material 11 on both sides of the stacking direction of the power generating element 14, which has a large area, the temperature around the exterior material 11 is less likely to affect the power generating element 14. This reduces the deterioration of performance of the battery 10 when the temperature around the battery 10 is low. Because solid electrolytes tend to have a significant decrease in ionic conductivity at low temperatures, the insulating materials 24, 27 are highly effective in reducing the deterioration of performance of the battery 10.

The insulating materials 24, 27 arranged on both sides of the power generating element 14 in the stacking direction buffer vibrations and mechanical shocks, making it difficult for vibrations and mechanical shocks to be transmitted to the power generating element 14. Because the area of the power generating element 14 viewed in the stacking direction of the power generating element 14 is larger than the area of the power generating element 14 viewed in a direction perpendicular to the stacking direction, the rigidity of the power generating element 14 in the stacking direction is lower than the rigidity of the power generating element 14 in the direction perpendicular to the stacking direction. Therefore, by arranging the insulating materials 24, 27 on both sides of the power generating element 14 in the stacking direction, damage to the power generating element 14 due to vibrations and mechanical shocks can be reduced.

The first portions 25, 28 of the insulating materials 24, 27 contact the entire surface of the power generating element 14 facing the stacking direction, and the second portions 26, 29 located around the first portions 25, 28 contact the side surfaces of the power generating element 14. This allows the corners and edges of the power generating element 14 to be covered by the insulating materials 24, 27, further reducing damage to the power generating element 14.

Because the thermal insulation materials 24, 27 have the second sections 26, 29, the area of the power generating element 14 covered by the thermal insulation materials 24, 27 is larger than when the second sections 26, 29 are not present. This makes it even less likely that the ambient temperature of the exterior packaging material 11 will affect the power generating element 14.

The second embodiment will be described with reference to Figure 2(b). In the second embodiment, parts that are the same as those described in the first embodiment are given the same reference numerals and will not be described again. Figure 2(b) is a cross-sectional view of a battery 30 in the second embodiment.

The battery 30 has heaters 31 and 32 disposed between the power generating element 14 and the insulating materials 24 and 27. In this embodiment, the heater 31 contacts the current collector 16, and the heater 32 contacts the current collector 20. The heater 31 is electrically insulated from the current collector 16, and the heater 32 is electrically insulated from the current collector 20. Examples of materials for the heaters 31 and 32 include metal, carbon, and ceramic. The heaters 31 and 32 may be PTC thermistors, NTC thermistors, CTR thermistors, or Peltier elements.

Electrical wires (not shown) that supply power from a power source to the heaters 31, 32 are connected to the heaters 31, 32. Power sources that supply power to the heaters 31, 32 include an external power source outside the exterior material 11 and the power generation element 14. When connecting the electrical wires that supply power to the heaters 31, 32 to an external power source, the electrical wires intersect with a part of the seal portion 13 and are pulled out to the outside of the exterior material 11. When connecting the electrical wires that supply power to the heaters 31, 32 to the power generation element 14, the electrical wires are housed in the exterior material 11.

The heaters 31, 32 are disposed between the power generating element 14 and the insulating materials 24, 27, which reduce heat dissipation from the heaters 31, 32 to the outside of the exterior packaging material 11. The heaters 31, 32 heat the power generating element 14 while reducing the power consumption of the heaters 31, 32, thereby reducing performance degradation of the battery 30.

A third embodiment will be described with reference to Figures 3 and 4(a). In the third embodiment, parts that are the same as those described in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted. Figure 3 is an exploded three-dimensional view of a battery 40 in the third embodiment. The battery 40 includes a container 41 in which the power generating element 14 is placed, and exterior materials 49, 50 that house the power generating element 14 and container 41.

The container 41 comprises a first plate 42, which is a rectangular plate; a second plate 43, which is a plate of approximately the same shape as the first plate 42 and is arranged approximately parallel to the first plate 42; a third plate 44, which is a rectangular plate connecting one side of the first plate 42 to one side of the second plate 43; a fourth plate 45, which is a plate of approximately the same shape as the third plate 44 and is arranged approximately parallel to the third plate 44 and connects another side of the first plate 42 to another side of the second plate 43; a fifth plate 46, which connects the first plate 42, the second plate 43, the third plate 44, and the fourth plate 45; and a lid 47, which is a plate of approximately the same shape as the fifth plate 46 and is arranged approximately parallel to the fifth plate 46 and is in contact with the first plate 42, the second plate 43, the third plate 44, and the fourth plate 45. The size of the first plate 42 and the second plate 43 when viewed from the stacking direction of the power generating element 14 is larger than the size of the power generating element 14 when viewed from the stacking direction of the power generating element 14.

The lid 47 has holes 48 through which the terminals 22, 23 pass. The terminals 22, 23 pass through the holes 48 and are pulled out of the container 41. To prevent short-circuiting of the power generating element 14, it is preferable that at least the inner surface of the container 41 be electrically insulating. Examples of materials for the container 41 include synthetic resin and metal. If the container 41 is made of metal, it is preferable that at least the inner surface of the container 41 be provided with an electrically insulating coating.

The distance between the third plate 44 and fourth plate 45 of the container 41, and the distance between the fifth plate 46 and the lid 47, are longer than the distance between the first plate 42 and second plate 43. Therefore, when a force perpendicular to each of the six faces is applied to the center of each face of the container 41, the first plate 42 and second plate 43 are more likely to elastically deform than the third plate 44, fourth plate 45, fifth plate 46, and lid 47.

The insulating material 51 is disposed between the first plate 42 of the container 41 and the power-generating element 14. The insulating material 52 is disposed between the second plate 43 of the container 41 and the power-generating element 14. The insulating material 53 is disposed between the third plate 44, fourth plate 45, and fifth plate 46 of the container 41 and the power-generating element 14. The size of the insulating materials 51, 52, and 53 is smaller than the size of each surface of the power-generating element 14 with which they respectively contact. Examples of the insulating materials 51, 52, and 53 include porous bodies made of synthetic resins such as polystyrene, polyethylene, and urethane; porous bodies made of inorganic materials such as silica; porous bodies made of rubber; and glass wool. The thermal conductivity of the insulating materials 51, 52, and 53 is, for example, 0.1 W/m·K or less.

Like the exterior material 11, the exterior materials 49 and 50 include, for example, a surface layer, a barrier layer, and an adhesive layer (none of which are shown), in that order. The exterior material 49 is disposed over the first plate 42 of the container 41. The exterior material 50 is disposed over the second plate 43 of the container 41. The exterior materials 49 and 50 are softer than the container 41.

Figure 4(a) is a cross-sectional view of battery 40. A seal portion 54 is created by welding the adhesive layers of exterior materials 49, 50. In this embodiment, seal portion 54 is provided around the entire periphery of exterior materials 49, 50. Terminals 22, 23 intersect with part of seal portion 54 and are pulled out to the outside of exterior materials 49, 50.

Insulating materials 51, 52, and 53 are interposed between the container 41 and the power-generating element 14, so that the power-generating element 14 is positioned within the container 41 at a distance from the container 41. The size of the insulating materials 51, 52, and 53 is smaller than the size of each surface of the power-generating element 14 with which the insulating materials 51, 52, and 53 are in contact. Therefore, spaces 55, 56, and 57 are provided between the first plate 42 and the power-generating element 14, between the second plate 43 and the power-generating element 14, and between the fifth plate 46 and the power-generating element 14, respectively. The spaces 55, 56, and 57 are interconnected. When the seal portion 54 is formed and the exterior materials 49 and 50 are sealed, the spaces 55, 56, and 57 are decompressed, so the air pressure in the spaces 55, 56, and 57 is lower than atmospheric pressure. The spaces 55, 56, and 57 may be in a medium vacuum, high vacuum, or ultra-high vacuum.

On both sides of the stacking direction of the power generating element 14, insulating materials 51, 52 are interposed between the container 41 housed in the exterior materials 49, 50 and the power generating element 14, making it less likely that the temperature around the exterior material 11 will affect the power generating element 14. Furthermore, insulating material 53 is interposed between the container 41 and the power generating element 14, making it less likely that the temperature around the exterior materials 49, 50 will affect the power generating element 14 than if the power generating element 14 were in contact with the fifth plate 46.

Because the power generating element 14 is placed inside the container 41, external forces such as bending and compression are less likely to be applied to the power generating element 14 than if the container 41 were not present. This reduces damage to the power generating element 14. Furthermore, the insulating materials 51, 52, and 53 located between the container 41 and the power generating element 14 buffer vibrations and mechanical shocks. This makes it less likely that vibrations or mechanical shocks will be transmitted to the power generating element 14.

The insulating materials 51, 52 are interposed between the first plate 42 and the second plate 43, which are more susceptible to elastic deformation than the third plate 44, the fourth plate 45, the fifth plate 46, and the lid 47, and the power generating element 14. This makes the power generating element 14 less susceptible to deformation of the first plate 42 and the second plate 43. This reduces damage to the power generating element 14.

The air pressure in spaces 55, 56, which are located between the power generating element 14 and the first plate 42 and second plate 43 and are positioned in the stacking direction of the power generating element 14, is lower than atmospheric pressure, so so-called vacuum insulation makes it difficult for the temperature around the exterior materials 49, 50 to affect the power generating element 14. The air pressure in space 57, which is located between the side surface of the power generating element 14 and the fifth plate 46, is also lower than atmospheric pressure, making it even less likely for the temperature around the exterior materials 49, 50 to affect the power generating element 14.

The area of the power generating element 14 as viewed from the stacking direction is larger than the area of the power generating element 14 as viewed from a direction perpendicular to the stacking direction. Since the amount of heat transferred from an object when there is a temperature difference is proportional to the area of the object, providing reduced-pressure spaces 55, 56 between the power generating element 14 and the exterior materials 49, 50 can improve insulation performance compared to providing only space 57.

The fourth embodiment will be described with reference to Figure 4(b). In the fourth embodiment, parts that are the same as those described in the first or third embodiment are given the same reference numerals, and the following description will be omitted. Figure 4(b) is a cross-sectional view of a battery 60 in the fourth embodiment.

The battery 60 has heaters 61 and 62 disposed between the power generating element 14 and the insulating materials 51 and 52. In this embodiment, the heater 61 contacts the current collector 16 (see Figure 2(a)), and the heater 62 contacts the current collector 20. The heater 61 is electrically insulated from the current collector 16, and the heater 62 is electrically insulated from the current collector 20.

The heaters 61, 62 are disposed between the power generating element 14 and the insulating materials 51, 52, and the insulating materials 51, 52 and the spaces 55, 56 reduce heat dissipation from the heaters 61, 62 to the outside of the exterior packaging material 11. The heaters 61, 62 heat the power generating element 14 while reducing the power consumption of the heaters 61, 62, thereby reducing performance degradation of the battery 60.

The fifth embodiment will be described with reference to Figure 5(a). In the fifth embodiment, parts that are the same as those described in the first embodiment are given the same reference numerals, and their description will be omitted below. Figure 5(a) is a cross-sectional view of a battery 70 in the fifth embodiment.

The battery 70 comprises plates 71 and 72 arranged on both sides of the power generating element 14 in the stacking direction, and an exterior material 11 that houses the power generating element 14 and plates 71 and 72. The plates 71 and 72 are larger in size when viewed from the stacking direction of the power generating element 14 than the power generating element 14 when viewed from the stacking direction of the power generating element 14. An insulating material 51 is interposed between the plate 71 and the power generating element 14, and an insulating material 52 is interposed between the plate 72 and the power generating element 14. The insulating materials 51 and 52 and the plates 71 and 72 are fixed to the power generating element 14 by the exterior material 11.

To prevent short-circuiting of the power generating element 14, it is preferable that at least the surfaces of the plates 71 and 72 facing inward are electrically insulating. The plates 71 and 72 are harder than the exterior material 11. Examples of materials for the plates 71 and 72 include synthetic resin and metal. If the plates 71 and 72 are made of metal, it is preferable that at least the surfaces facing inward of the plates 71 and 72 be provided with an electrically insulating coating.

Spaces 73 and 74 are provided between plate 71 and the power-generating element 14, and between plate 72 and the power-generating element 14, respectively. Spaces 73 and 74 are connected to each other. When seal portion 13 is created and exterior material 11 is sealed, spaces 73 and 74 are depressurized, so the air pressure in spaces 73 and 74 is lower than atmospheric pressure. Spaces 73 and 74 may be a medium vacuum, high vacuum, or ultra-high vacuum. Because the internal spaces 73 and 74 of exterior material 11 are depressurized, portion 11b of exterior material 11 between plates 71 and 72 (the portion where plates 71, 72 and power-generating element 14 are not present) is recessed.

On both sides of the power generating element 14 in the stacking direction, insulating materials 51, 52 are interposed between the power generating element 14 and the plates 71, 72 housed in the exterior material 11, making it less likely that the temperature around the exterior material 11 will affect the power generating element 14. The air pressure in the spaces 73, 74 in the stacking direction of the power generating element 14, which are located between the power generating element 14 and the plates 71, 72, is lower than atmospheric pressure, making it even less likely that the temperature around the exterior material 11 will affect the power generating element 14 due to so-called vacuum insulation.

Because the power generating element 14 is sandwiched between the plates 71 and 72 via the insulating materials 51 and 52, external forces such as bending and compression are less likely to be applied to the power generating element 14 than if the plates 71 and 72 were not present. This reduces damage to the power generating element 14.

Because the plates 71, 72 are larger than the power generating element 14, when a large mechanical shock is applied to the plates 71, 72, such as when the battery 70 is dropped, the mechanical shock applied to the power generating element 14 can be reduced. The insulating materials 51, 52 interposed between the plates 71, 72 and the power generating element 14 buffer vibrations and mechanical shocks, reducing the vibrations and mechanical shocks transmitted from the plates 71, 72 to the power generating element 14.

The sixth embodiment will be described with reference to Figure 5(b). In the sixth embodiment, parts that are the same as those described in the first or fifth embodiment are given the same reference numerals, and the following description will be omitted. Figure 5(b) is a cross-sectional view of a battery 80 in the sixth embodiment.

The battery 80 includes plates 71 and 72 arranged on both sides of the power generating element 14 in the stacking direction, an exterior material 11 that houses the power generating element 14 and plates 71 and 72, an insulating material 81 interposed between the plate 71 and the power generating element 14, and an insulating material 83 interposed between the plate 72 and the power generating element 14.

The insulating material 81 includes a plurality of needle-shaped protrusions 82 that protrude from the surface of the plate 71 toward the power generating element 14 and whose tips contact the power generating element 14, and a space 73 between the power generating element 14 and the plate 71, separated by the protrusions 82. In this embodiment, the protrusions 82 are an integrally molded product made integral with the plate 71. The protrusions 82 are in point contact with the power generating element 14. Because the area where the protrusions 82 contact the power generating element 14 is small and a space 73 is present between the plate 71 and the power generating element 14, thermal resistance is increased and insulating performance can be ensured.

The insulating material 83 includes a plurality of conical protrusions 84 that protrude from the surface of the plate 72 toward the power generating element 14 and whose tips contact the power generating element 14, and a space 74 between the power generating element 14 and the plate 72, separated by the protrusions 84. In this embodiment, the protrusions 84 are an integrally molded part made integral with the plate 72. The protrusions 84 are in point contact with the power generating element 14. Because the area where the protrusions 84 contact the power generating element 14 is small and a space 74 is present between the plate 72 and the power generating element 14, thermal resistance is increased and insulating performance can be ensured.

The exterior material 11 keeps the protrusions 82, 84 in contact with the power-generating element 14. Because the air pressure in the spaces 73, 74 is lower than atmospheric pressure, the insulating performance of the insulating materials 81, 83 is further improved by so-called vacuum insulation. The thermal conductivity of the insulating materials 81, 83, including the spaces 73, 74, is preferably 0.1 W/m·K or less.

The seventh embodiment will be described with reference to Figure 6(a). In the seventh embodiment, parts that are the same as those described in the first embodiment are given the same reference numerals and will not be described again. Figure 6(a) is a cross-sectional view of a battery 90 in the seventh embodiment.

The battery 90 includes insulating materials 91, 93 arranged on both sides of the power generating element 14 in the stacking direction, and an exterior material 11 that houses the power generating element 14 and the insulating materials 91, 93. The exterior material 11 keeps the power generating element 14 sandwiched between the insulating materials 91, 93 in the stacking direction of the power generating element 14. The insulating materials 91, 93 are plate materials whose size, when viewed from the stacking direction of the power generating element 14, is approximately the same as that of the power generating element 14 when viewed from the stacking direction.

The insulating materials 91 and 93 are porous bodies. Examples of porous materials include synthetic resins such as polystyrene, polyethylene, and urethane, and inorganic materials such as silica. The pores in the insulating materials 91 and 93 include closed pores that are isolated within the object, and open pores that are connected to the outside of the object. The air pressure in the pores 92 and 94 (open pores) of the insulating materials 91 and 93 that are connected to the outside of the object is lower than atmospheric pressure. The pores 92 and 94 may be in a medium vacuum, high vacuum, or ultra-high vacuum. The insulating performance of the insulating materials 91 and 93 is further improved by so-called vacuum insulation.

The eighth embodiment will be described with reference to Figure 6(b). In the eighth embodiment, parts that are the same as those described in the first or fifth embodiment are given the same reference numerals, and the following description will be omitted. Figure 6(b) is a cross-sectional view of the battery 100 in the eighth embodiment.

The battery 100 includes plates 71, 72 arranged on both sides of the power generating element 14 in the stacking direction, thermal insulation materials 91, 93 arranged between the plates 71, 72 and the power generating element 14, respectively, and an exterior material 11 that houses the power generating element 14, the plates 71, 72, and the thermal insulation materials 91, 93. The exterior material 11 maintains the overlapping state of the plates 71, 72, the thermal insulation materials 91, 93, and the power generating element 14 in the stacking direction of the power generating element 14. The size of the plates 71, 72 when viewed from the stacking direction of the power generating element 14 is larger than the size of the thermal insulation materials 91, 93 when viewed from the stacking direction of the power generating element 14.

The mechanical strength of plates 71 and 72 is greater than that of the insulating materials 91 and 93, and the power generating element 14 is sandwiched between plates 71 and 72 via the insulating materials 91 and 93, thereby increasing the mechanical strength of battery 100 compared to when plates 71 and 72 are not present.

The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments, and it is readily apparent that various improvements and modifications are possible within the spirit and scope of the present invention. The shapes of the power generating element 14 and the heat insulating materials 24, 27, 51, 52, 53, 81, 83, 91, and 93 are merely examples and can be set as appropriate.

In the embodiment, the power generating element 14 has been described in which an active material layer 17 is provided on one side of the current collector 16 of the positive electrode 15, an active material layer 21 is provided on one side of the current collector 20 of the negative electrode 19, and a solid electrolyte layer 18 is disposed between the active material layer 17 and the active material layer 21. However, this is not necessarily limited to this. For example, it is possible to alternately stack electrodes (so-called bipolar electrodes) in which an active material layer 17 is provided on one side of a current collector and an active material layer 21 is provided on the other side of the same current collector, and solid electrolyte layers 18, and house these in a single exterior material to form a power generating element 14 with a so-called bipolar structure.

In the embodiment, a lithium ion battery in which the ion-conducting carrier is Li ⁺ has been described as the power generating element 14, but this is not necessarily limited to this. Naturally, other carriers can be used for the power generating element 14. An example of another power generating element 14 is a sodium ion battery.

In the embodiment, the terminals 22 and 23 of the power generating element 14 are described as being drawn out in the same direction, but this is not necessarily limited to this. For example, it is of course possible for the terminals 22 and 23 to be drawn out in different directions.

In the second and fourth embodiments, heaters are disposed on both sides of the power-generating element 14 in the stacking direction. However, this is not necessarily limited to this. It is of course possible to omit one of the heaters 31, 32 in the second embodiment, or one of the heaters 61, 62 in the fourth embodiment. Furthermore, the heater is not limited to being disposed outside the power-generating element 14. It is of course possible to dispose a heater inside the power-generating element 14. It is of course possible to incorporate a heater into the batteries 70, 80, 90, and 100 in the fifth to eighth embodiments.

In the third to sixth embodiments, a space is provided on both sides of the power-generating element 14 in the stacking direction. However, this is not necessarily limited to this. It is of course possible to omit one of the spaces 55, 56 in the third and fourth embodiments, or to omit one of the spaces 73, 74 in the fifth and sixth embodiments. To omit one of the spaces 55, 56, simply replace one of the insulating materials 51, 52 with one of the insulating materials 24, 27, 91, or 93. To omit one of the spaces 73, 74, simply replace one of the insulating materials 81, 83 with one of the insulating materials 24, 27, 91, or 93.

In the third embodiment, the first plate 42, second plate 43, third plate 44, fourth plate 45, and fifth plate 46 of the container 41 are connected to one another, but this is not necessarily limited to this. At least one of the first plate 42, second plate 43, third plate 44, fourth plate 45, and fifth plate 46 may have a portion cut out, and the cut-out portion may be combined with the remaining portion.

In the sixth embodiment, needle-shaped protrusions 82 are provided on plate 71, and cone-shaped protrusions 84 are provided on plate 72, but this is not necessarily limited to this. The shape of the protrusions is appropriately set so that the area of contact of the protrusions with the power-generating element 14 is small. Examples of the shape of the protrusions include a cylindrical or columnar shape that makes point contact with the power-generating element 14, and a ridge shape that makes line contact with the power-generating element 14. Plates 71 and 72 may be provided with protrusions of the same shape, or the shapes of the protrusions provided on plates 71 and 72 may be different from each other. The number of protrusions provided on plates 71 and 72 may be the same or different.

In the first, second, and fifth to eighth embodiments, cases where seal portions 13 are provided on three sides of the exterior material 11 are described, and in the third and fourth embodiments, cases where seal portions 54 are provided on four sides of the exterior materials 49, 50 are described, but this is not necessarily limited to this. It is of course possible to use exterior material 11 instead of exterior material 49, 50 in the third embodiment, etc., or to use exterior material 49, 50 instead of exterior material 11 in the first embodiment, etc.

10, 30, 40, 60, 70, 80, 90, 100 Battery 11, 49, 50 Exterior material 14 Power generating element 15 Positive electrode 18 Solid electrolyte layer 19 Negative electrode 24, 27, 51, 52, 53, 81, 83, 91, 93 Heat insulator 31, 32, 61, 62 Heater 55, 56, 73, 74 Space 92, 94 Hole

Claims (9)

A battery comprising: a power generating element formed by laminating a positive electrode, a solid electrolyte layer, and a negative electrode; and an exterior material that houses the power generating element and seals an internal space,
a heat insulating material is disposed between the power generating element and the exterior material on both sides of the power generating element in the stacking direction ,
The battery wherein the heat insulating material is a porous body, and the air pressure in the pores of the porous body is lower than atmospheric pressure . The battery described in claim 1, wherein a space is provided between the power generating element and the exterior material on at least one side of the stacking direction of the power generating element, and the air pressure in the space is lower than atmospheric pressure. 3. The battery according to claim 1, wherein the thermal conductivity of the heat insulating material is 0.1 W/m·K or less. 4. The battery according to claim 1, further comprising a heater disposed between the power generating element and the heat insulating material. A battery comprising: a power generating element formed by laminating a positive electrode, a solid electrolyte layer, and a negative electrode; and an exterior material that houses the power generating element,
a heat insulating material is disposed between the power generating element and the exterior material on both sides of the power generating element in the stacking direction,
A battery in which a plate harder than the exterior material is disposed between the power generating element and the exterior material, and the heat insulating material is disposed between the plate and the power generating element. 6. The battery according to claim 5, wherein the size of the plate as viewed from the stacking direction of the power generating element is larger than the size of the power generating element as viewed from the stacking direction of the power generating element. The size of the heat insulating material is smaller than the size of the surface of the power generating element that is in contact with the heat insulating material,
7. The battery according to claim 5, wherein the pressure in the space between the plate and the power generating element is lower than atmospheric pressure. 7. The battery according to claim 5, wherein the insulating material includes a protrusion that protrudes from the surface of the plate toward the power generating element and whose tip contacts the power generating element, and a space between the power generating element and the plate separated by the protrusion. 9. The battery of claim 8, wherein the pressure in said space is lower than atmospheric pressure .