JP2019087525A - All-solid-state battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the short-circuit resistance of a short-circuit current disperser at the time of nail penetration in an all-solid-state battery provided with the short-circuit disperser. An all-solid-state battery in which at least one short-circuit current disperser and a plurality of power generation elements are stacked, wherein a first current collector layer and a second current-collector layer are provided in the short-circuit current disperser. And an insulating layer provided between the first current collector layer and the second current collector layer, and the positive electrode current collector layer, the positive electrode material layer, and the solid electrolyte in the power generation element. A layer, a negative electrode material layer, and a negative electrode current collector layer are laminated, the first current collector layer is electrically connected to the positive electrode current collector layer, and the second current collector layer is Is electrically connected to the negative electrode current collector layer, the plurality of power generating elements are electrically connected in parallel, the first current collector layer and the first current collector layer of the short-circuit current spreader. Of the two current collector layers, at least the current collector layer arranged on the piercing side in the nail piercing direction in the nail piercing test is made up of a plurality of metal foils to provide an all-solid-state battery. [Selection diagram] Figure 1

Description

  The present application discloses an all solid state battery.

  Patent Document 1 discloses a laminate type polymer electrolyte battery provided with a short circuit formation and heat radiation promotion unit in which two metal plates are disposed outside the laminate electrode group via an insulator. According to the battery disclosed in Patent Document 1, when the electrodes are short-circuited at the time of a nail penetration test of the battery or the like, the voltage of the power generation element can be reduced by flowing the short circuit current to the short circuit formation and heat radiation promotion unit. It is considered that the heat generated by the unit or the like can be dissipated to the outside smoothly. Patent Documents 2 to 4 also disclose various techniques for suppressing the generation of heat due to internal short circuiting of a battery such as a nail stick.

JP, 2001-068156, A Patent No. 6027262 JP, 2015-072835, A JP, 2015-018710, A

  In an all-solid-state battery in which a plurality of power generation elements are connected in parallel and electrically connected in parallel, when the power generation elements are short-circuited by a nail penetration test, electrons flow from some of the power generation elements into the other power generation elements Is sometimes referred to as “loop current”), there is a problem that the temperature of some of the power generation elements rises locally. To solve this problem, a short circuit current dispersion is provided separately from the power generation element, and in the nail penetration test, the short circuit current dispersion is also shorted together with some of the power generation elements. It can be considered that local temperature increase of only some of the power generation elements can be prevented by dispersing the power generation elements not only with small resistance but also into the short circuit current dispersion with low short circuit resistance (FIG. 9) .

  The short circuit current dispersion can be constituted by the first current collector layer, the second current collector layer, and the insulating layer provided therebetween. For example, as disclosed in Patent Documents 1 and 2, it is possible to form the insulating layer using various resins. Alternatively, as disclosed in Patent Document 2, the insulating layer may be configured using a ceramic material or a battery separator. Alternatively, as disclosed in Patent Document 3, the surface of the current collector layer may be covered with a thin insulating film. On the other hand, the first current collector layer and the second current collector layer may be made of metal foils as disclosed in Patent Documents 1 to 4. Thereby, the first current collector layer and the second current collector layer can be insulated by the insulating layer during normal use, and the first current collector layer and the second current collector layer can be insulated at the time of nailing. It also seems possible to short-circuit the short-circuit current dispersion by bringing

  However, when the short circuit current dispersion is constructed by diverting the techniques disclosed in Patent Documents 1 to 4, the present inventors may newly find that the short circuit resistance of the short circuit current dispersion may not be stable when nailing. Hit an interesting task. If the short circuit resistance of the short circuit current dispersion is unstable, the wraparound current can not be efficiently dispersed to the short circuit current dispersion, and there is a possibility that Joule heat generation of the power generation element can not be suppressed.

  The present application is an all-solid battery in which at least one short circuit current dispersion and a plurality of power generation elements are stacked, as one of means for solving the above-mentioned problems, A current collector layer, a second current collector layer, and an insulating layer provided between the first current collector layer and the second current collector layer are laminated, and in the power generation element, A positive electrode current collector layer, a positive electrode material layer, a solid electrolyte layer, a negative electrode material layer, and a negative electrode current collector layer are laminated, and the first current collector layer is electrically connected to the positive electrode current collector layer. And the second current collector layer is electrically connected to the negative electrode current collector layer, and the plurality of power generation elements are electrically connected in parallel, and the first current collector layer At least a current collector of the current collector layer and the second current collector layer on the side where the nail is to be pierced in the nail penetration test. In a plurality of metal foils are stacked along a stacking direction of the first current collector layer and the insulating layer and the second collector layer, discloses an all-solid battery.

"The side to which the nail is pierced" refers to the nail head side (upstream side in the nail piercing direction) after the nail penetration in the nail penetration test is completed. On the other hand, "the side on which the nail is pierced" means the tip side of the nail (downstream side in the nail piercing direction) after the nail penetration in the nail penetration test is completed.
“In the current collector layer, a plurality of metal foils are laminated” means, for example, in a cross-sectional shape by folding a single metal foil, in addition to a form in which a plurality of metal foils are superimposed. It may be in a form in which a plurality of metal foils are laminated.

  In the all solid state battery of the present disclosure, the short circuit current dispersion is laminated outside the plurality of power generation elements, and at least one of the first current collector layer and the second current collector layer, In the current collector layer disposed outside, a plurality of metal foils are laminated along the stacking direction of the first current collector layer, the insulating layer, and the second current collector layer. preferable.

  In the all-solid-state battery of the present disclosure, stacking directions of the positive electrode current collector layer, the positive electrode material layer, the solid electrolyte layer, the negative electrode material layer, and the negative electrode current collector layer in the power generation element; Stacking direction, the stacking direction of the first current collector layer, the insulating layer, and the second current collector layer in the short circuit current dispersion, and the short circuit current dispersion and the plurality of power generation elements It is preferable that the stacking direction of the same be the same.

  In the all-solid-state battery of the present disclosure, the thickness per sheet of the plurality of metal foils is preferably 9 μm or more and 15 μm or less.

  In the all-solid-state battery of the present disclosure, the thickness per sheet of the plurality of metal foils is preferably 9 μm or more and 15 μm or less, and the number of the plurality of metal foils is preferably 4 or more and 7 or less.

  According to the findings of the present inventors, when the short circuit current dispersion is constructed by diverting the techniques disclosed in Patent Documents 1 to 4, the first current collector layer is formed when the short circuit current dispersion is nailed. The contact with the second current collector layer is not stably maintained, which causes the short circuit resistance to be unstable. The contact between the first current collector layer and the second current collector layer is not stably maintained when the short circuit current dispersion is nailed, the current collector layer may be melted away due to Joule heat, or the nail may be broken. It is considered that the connection between the current collector layers is released or the like due to the temporal deformation of the current collector layer with the progress of In order to stably maintain the contact between the first current collector layer and the second current collector layer when the short circuit current dispersion is nailed, the first current collector layer and the second current collector layer can be stably held. It can be said effective to increase the probability of contact with the second current collector layer and to increase the contact area between the first current collector layer and the second current collector layer.

  In the all-solid-state battery of the present disclosure, of the first current collector layer and the second current collector layer that constitute the short circuit current dispersion, the current collector layer on the side where the nail is pierced in the nail penetration test. Several metal foils are laminated. In this case, when the short circuit current dispersion is nailed, the plurality of metal foils of one current collector layer respectively project toward the other current collector layer, and one current collector layer and the other current collector A plurality of contact points and contact surfaces are easily formed with the layer. That is, according to the all-solid-state battery of the present disclosure, the contact between the first current collector layer and the second current collector layer is improved when nailing to the short circuit current dispersion, and the short circuit current dispersion is obtained. Short circuit resistance can be stabilized.

FIG. 2 is a schematic diagram for explaining a layer configuration of all-solid battery 100. FIG. 2 is a schematic diagram for explaining a layer configuration of a short circuit current dispersion body 10; (A) is an external appearance perspective view, (B) is IIB-IIB sectional drawing. FIG. 7 is a schematic view for explaining a layer configuration of the power generation element 20. (A) is an external appearance perspective view, (B) is a IIIB-IIIB sectional view. It is the schematic for demonstrating the nail penetration test method with respect to a short circuit current dispersion. It is the result of confirming the stability of the short circuit resistance of the short circuit current dispersion in the nail penetration test regarding Comparative Example 1. FIG. 2 is a schematic view for explaining the configuration of a short circuit current dispersion according to Example 1; FIG. 7 is a schematic view for explaining the configuration of a short circuit current dispersion according to Comparative Example 2; It is the result of confirming the stability of the short circuit resistance of the short circuit current dispersion in the nail penetration test regarding Example 1 and Comparative Example 2. In the all-solid-state battery with which the electric power generation element was connected in parallel, it is the schematic for demonstrating the wraparound electric current etc. which arise at the time of a nail penetration.

1. All solid battery 100
The layer configuration of the all-solid battery 100 is schematically shown in FIG. In FIG. 1, for convenience of description, connection portions between current collector layers (current collection tabs), a battery case, and the like are omitted. FIG. 2 schematically shows the layer configuration of the short circuit current dispersion 10 constituting the all solid state battery 100. 2A is an external perspective view, and FIG. 2B is a cross-sectional view taken along the line IIB-IIB. FIG. 3 schematically shows the layer configuration of the power generation element 20 constituting the all solid state battery 100. As shown in FIG. FIG. 3A is an external perspective view, and FIG. 3B is a cross-sectional view taken along the line IIIB-IIIB.

  As shown to FIGS. 1-3, the all-solid-state battery 100 laminates | stacks the at least 1 short circuit current dispersion body 10 and several electric power generation element 20 (electric power generation element 20a and 20b). In the short-circuit current dispersion 10, an insulating layer provided between the first current collector layer 11, the second current collector layer 12, the first current collector layer 11, and the second current collector layer 12 13 and are stacked. In the power generation elements 20a and 20b, the positive electrode current collector layer 21, the positive electrode material layer 22, the solid electrolyte layer 23, the negative electrode material layer 24, and the negative electrode current collector layer 25 are stacked. In the all solid state battery 100, the first current collector layer 11 is electrically connected to the positive electrode current collector layer 21, and the second current collector layer 12 is electrically connected to the negative electrode current collector layer 25. The plurality of power generation elements are electrically connected in parallel. Here, in the all-solid-state battery 100, at least one of the first current collector layer 11 and the second current collector layer 12 of the short circuit current dispersion 10 is disposed on the side where the nail is to be punctured in the nail penetration test. In the current collector layer (in FIG. 1, the first current collector layer 11 corresponds to this), the plurality of metal foils are the first current collector layer 11, the insulating layer 13 and the second current collector. It is characterized in that it is stacked along the stacking direction with the body layer 12.

1.1. Short circuit current dispersion 10
The short circuit current dispersion 10 is an insulation provided between the first current collector layer 11, the second current collector layer 12, and the first current collector layer 11 and the second current collector layer 12. And a layer 13. In the short-circuit current dispersion 10 having such a configuration, while the first current collector layer 11 and the second current collector layer 12 are appropriately insulated by the insulating layer 13 during normal use of the battery, At the time of nailing, the first current collector layer 11 and the second current collector layer 12 are in contact with each other to reduce the electrical resistance.

1.1.1. First, a current collector layer disposed on the nail penetration side in the nail penetration test The “current collector layer disposed on the nail penetration side in the nail penetration test” in the present application will be described. In an all-solid-state battery, when a short circuit current dispersion is interposed between a plurality of power generation elements and laminated (ie, the short circuit current dispersion is sandwiched between the power generation element and the power generation element) Any of the first current collector layer and the second current collector layer of the body can be the "current collector layer disposed on the side where the nail is to be pierced in the nail penetration test". Therefore, in this case, both of the first current collector layer and the second current collector layer are preferably made of a plurality of metal foils.
On the other hand, as shown in FIG. 1, when the short circuit current dispersion 10 is laminated outside the plurality of power generation elements 20, the first current collector layer 11 and the second current collection of the short circuit current dispersion 10 The current collector layer disposed on the outer side of the body layer 12 is the “current collector layer disposed on the side where the nail is to be pierced in the nail penetration test”. Therefore, in this case, at least the current collector layer of the first current collector layer 11 and the second current collector layer 12 of the short-circuit current dispersion 10 (the first current collector layer in FIG. 1). And the plurality of metal foils are laminated along the stacking direction of the first current collector layer 11, the insulating layer 13, and the second current collector layer 12). Is preferred.

  In the all-solid-state battery 100, the first current collector layer 11 disposed on the side where the nail is to be pierced at the time of the nail penetration test is constituted by a plurality of metal foils. As a metal which comprises the said metal foil, Cu, Ni, Al, Fe, Ti, Zn, Co, Cr, Au, Pt, stainless steel etc. are mentioned. The metal foil may have on its surface any layer for adjusting the contact resistance.

  The thickness per metal foil in the first current collector layer 11 is not particularly limited as long as it is a thickness common to metal foils, but from the viewpoint of exerting more remarkable effects, It is preferable to make thickness per metal foil into 1 micrometer or more and 90 micrometers or less. The lower limit is more preferably 7 μm or more, still more preferably 9 μm or more, and the upper limit is more preferably 20 μm or less, still more preferably 15 μm or less.

  The thickness of the first current collector layer 11 as a whole is not particularly limited. In consideration of the volume energy density of the battery, etc., it is preferable to make the thickness of the first current collector layer 11 as thin as possible, but from the viewpoint of further stabilizing the short circuit resistance of the short circuit current dispersion 10 at the time of nailing. It is considered preferable to make the thickness of the first current collector layer 11 as thick as possible. For example, it is preferable to set the thickness of the entire first current collector layer 11 to 20 μm or more and 2 mm or less. The lower limit is more preferably 30 μm or more, still more preferably 36 μm or more, and the upper limit is more preferably 0.2 mm or less, still more preferably 105 μm or less.

  The number of metal foils in the first current collector layer 11 is not particularly limited. From the viewpoint of exerting a more remarkable effect, for example, the number of metal foils is preferably 2 or more and 200 or less. The lower limit is more preferably 4 or more, and the upper limit is more preferably 20 or less, still more preferably 7 or less.

  As shown in FIG. 2, the first current collector layer 11 includes a current collection tab 11a, and is electrically connected to the positive electrode current collector layer 21 of the power generation element 20 via the current collection tab 11a. Is preferred. The current collection tab 11a may be the same material as the first current collector layer 11, or may be a different material.

1.1.2. Current collector layer disposed on the side where the nail is pierced in the nail penetration test The second current collector layer 12 disposed on the side where the nail is pierced in the nail penetration test is a metal foil in the all solid battery 100. Or a metal mesh or the like. In particular, metal foils are preferred. Examples of the metal constituting the second current collector layer 12 include Cu, Ni, Al, Fe, Ti, Zn, Co, Cr, Au, Pt, stainless steel and the like. The second current collector layer 12 may have on its surface any layer for adjusting the contact resistance.

  The thickness of the second current collector layer 12 is not particularly limited. For example, the thickness is preferably 0.1 μm or more and 1 mm or less, and more preferably 1 μm or more and 100 μm or less. When the thickness of the second current collector layer 12 is in such a range, the first current collector layer 11 and the second current collector layer 12 can be more appropriately brought into contact with each other at the time of nailing. The short circuit current dispersion 10 can be short-circuited more appropriately.

  As shown in FIG. 2, the second current collector layer 12 is provided with a current collecting tab 12a, and is electrically connected to the negative electrode current collector layer 25 of the power generation element 20 via the current collecting tab 12a. Is preferred. The current collection tab 12a may be the same material as the second current collector layer 12 or may be a different material.

  In the all-solid-state battery of the present disclosure, at least the side of the first current collector layer 11 and the second current collector layer 12 of the short circuit current dispersion 10 to which the nail is to be punctured in the nail penetration test. The current collector layer to be disposed may be made of a plurality of metal foils. Therefore, in addition to the form in which only the first current collector layer 11 is constituted by a plurality of metal foils as described above, both of the first current collector layer 11 and the second current collector layer 12 are plural. It is also possible to use a form constituted by metal foils of

1.1.3. Insulating layer 13
In the all-solid-state battery 100, the insulating layer 13 only needs to insulate the first current collector layer 11 and the second current collector layer 12 during normal use of the battery. The insulating layer 13 may be an insulating layer made of an organic material, an insulating layer made of an inorganic material, or an insulating layer in which an organic material and an inorganic material are mixed. In particular, an insulating layer made of an organic material is preferable. This is because the insulating layer made of an organic material is advantageous from the viewpoint that the probability of occurrence of a short circuit due to a crack is low in normal use, as compared with the insulating layer made of an inorganic material.

  As an organic material which can constitute insulating layer 13, various resin is mentioned. For example, various thermoplastic resins and various thermosetting resins. In particular, super engineering plastics such as polyimide, polyamideimide, polyetheretherketone and polyphenylene sulfide are preferable. In general, thermosetting resins have higher thermal stability than thermoplastic resins, and are hard and brittle. That is, in the case where the insulating layer 13 is formed of a thermosetting resin, when the short circuiting current dispersion 10 is nailed, the insulating layer 13 is easily broken, and the first current collector layer 11 or the second current collector layer 11 is formed. It can be suppressed that the insulating layer 13 follows the deformation of the current collector layer 12, and the first current collector layer 11 and the second current collector layer 12 can be more easily brought into contact with each other. Moreover, even if the temperature of the insulating layer 13 rises, thermal decomposition can be suppressed. From this viewpoint, the insulating layer 13 is preferably formed of a thermosetting resin sheet, and more preferably formed of a thermosetting polyimide resin sheet.

  As an inorganic material which can constitute insulating layer 13, various ceramics are mentioned. For example, it is an inorganic oxide. The insulating layer 13 may be formed of a metal foil having an oxide film on the surface. For example, an anodized film is formed on the surface of the aluminum foil by alumite treatment to obtain an aluminum foil having an aluminum oxide film as an insulating layer on the surface. In this case, the thickness of the aluminum oxide film is preferably 0.01 μm to 5 μm. The lower limit is more preferably 0.1 μm or more, and the upper limit is more preferably 1 μm or less.

  The thickness of the insulating layer 13 is not particularly limited. For example, the thickness is preferably 0.1 μm or more and 1 mm or less, and more preferably 1 μm or more and 100 μm or less. When the thickness of the insulating layer 13 is in such a range, the first current collector layer 11 and the second current collector layer 12 can be more appropriately insulated during normal use of the battery, and the nail The first current collector layer 11 and the second current collector layer 12 can be more appropriately conducted by the deformation due to external stress such as stabbing, so that the short circuit current dispersion 10 can be short-circuited.

1.2. Power generation element 20 (20a, 20b)
In the all-solid battery 100, the power generation elements 20a and 20b are formed by laminating the positive electrode current collector layer 21, the positive electrode material layer 22, the solid electrolyte layer 23, the negative electrode material layer 24, and the negative electrode current collector layer 25, respectively. That is, each of the power generation elements 20a and 20b can function as a single cell.

1.2.1. Positive electrode current collector layer 21
The positive electrode current collector layer 21 may be made of metal foil, metal mesh or the like. In particular, metal foils are preferred. As a metal which comprises the positive electrode collector layer 21, Ni, Cr, Au, Pt, Al, Fe, Ti, Zn, stainless steel etc. are mentioned. The positive electrode current collector layer 21 may have on the surface thereof any coating layer for adjusting the contact resistance. For example, a coat layer or the like containing a conductive material and a resin. The thickness of the positive electrode current collector layer 21 is not particularly limited. For example, the thickness is preferably 0.1 μm or more and 1 mm or less, and more preferably 1 μm or more and 100 μm or less.

  As shown in FIG. 3, the positive electrode current collector layer 21 is preferably provided with a positive electrode current collection tab 21 a at a part of the outer edge. The first current collector layer 11 and the positive electrode current collector layer 21 can be easily electrically connected by the tab 21a, and the positive electrode current collector layers 21 are easily electrically connected in parallel. be able to.

1.2.2. Positive electrode layer 22
The positive electrode material layer 22 is a layer containing at least an active material, and in addition to the active material, a solid electrolyte, a binder, a conductive auxiliary agent, and the like can be optionally added. A known active material may be used as the active material. Among the known active materials, two substances having different potentials (charge / discharge potentials) for occluding and releasing predetermined ions are selected, a substance showing a noble potential is used as a positive electrode active material, and a substance showing a false potential is described later. Each can be used as a negative electrode active material. For example, when configuring a lithium ion battery, various types of cathode active materials such as lithium cobaltate, lithium nickelate, LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , lithium manganate, spinel lithium compounds, etc. Lithium-containing composite oxides can be used. The surface of the positive electrode active material may be coated with an oxide layer such as a lithium niobate layer, a lithium titanate layer, or a lithium phosphate layer. The solid electrolyte that can be contained in the positive electrode material layer 22 is preferably an inorganic solid electrolyte. This is because the ion conductivity is higher than that of the organic polymer electrolyte. Moreover, it is because it is excellent in heat resistance compared with the organic polymer electrolyte. Furthermore, the pressure applied to the power generation element 20 at the time of nailing is higher than that of the organic polymer electrolyte, and the effect of the all-solid battery 100 of the present disclosure is considered to be remarkable. Preferred inorganic solid electrolytes, for example, lithium lanthanum _{zirconate, LiPON, Li 1 + X Al} X Ge 2-X (PO 4) 3, Li-SiO glass, Li-Al-S-O-based glass oxides such as solid Electrolyte: Li ₂ S-P ₂ S ₅ , Li ₂ S-SiS ₂ , LiI-Li ₂ S-SiS ₂ , LiI-Si ₂ S-P ₂ S ₅ , LiI-LiBr-Li ₂ S-P ₂ S _{5 , LiI-Li 2 S-P} 2 S 5, LiI-Li 2 S-P 2 O 5, LiI-Li 3 PO 4 -P 2 S 5, Li 2 S-P 2 S 5 -GeS sulfides such as ₂ A solid electrolyte can be illustrated. In particular, a sulfide solid electrolyte containing Li ₂ S-P ₂ S ₅ is more preferable, and a sulfide solid electrolyte containing 50 mol% or more of Li ₂ S-P ₂ S ₅ is more preferable. As a binder which may be contained in the positive electrode material layer 22, butadiene rubber (BR), acrylate butadiene rubber (ABR), polyvinylidene fluoride (PVdF) etc. are mentioned, for example. Examples of the conductive additive that may be contained in the positive electrode layer 22 include carbon materials such as acetylene black and ketjen black, and metal materials such as nickel, aluminum, and stainless steel. The content of each component in the positive electrode material layer 22 may be the same as that in the prior art. The shape of the positive electrode material layer 22 may be the same as that in the prior art. In particular, the sheet-like positive electrode material layer 22 is preferable from the viewpoint that the all-solid battery 100 can be easily configured. In this case, the thickness of the positive electrode material layer 22 is, for example, preferably 0.1 μm or more and 1 mm or less, and more preferably 1 μm or more and 150 μm or less.

1.2.3. Solid electrolyte layer 23
The solid electrolyte layer 23 is a layer containing at least a solid electrolyte, and can optionally further contain a binder in addition to the solid electrolyte. The solid electrolyte is preferably the above-mentioned inorganic solid electrolyte. The binder can be appropriately selected from various binders exemplified as those used for the positive electrode material layer 22 and used. The content of each component in the solid electrolyte layer 23 may be the same as that in the prior art. The shape of the solid electrolyte layer 23 may be the same as in the prior art. In particular, the sheet-like solid electrolyte layer 23 is preferable from the viewpoint that the all-solid battery 100 can be easily configured. In this case, the thickness of the solid electrolyte layer 23 is, for example, preferably 0.1 μm or more and 1 mm or less, and more preferably 1 μm or more and 100 μm or less.

1.2.4. Negative electrode material layer 24
The negative electrode material layer 24 is a layer containing at least an active material, and in addition to the active material, a solid electrolyte, a binder, a conductive auxiliary agent, and the like can be optionally added. A known active material may be used as the active material. Among the known active materials, two substances having different potentials (charge / discharge potentials) for occluding and releasing predetermined ions are selected, a substance exhibiting a noble potential is used as the above-mentioned positive electrode active substance, and a substance showing a negative potential is selected. Each can be used as a negative electrode active material. For example, when constructing a lithium ion battery, it is possible to use, as a negative electrode active material, Si or Si alloy; carbon material such as graphite or hard carbon; various oxides such as lithium titanate; metallic lithium or lithium alloy. The solid electrolyte, the binder, and the conductive auxiliary agent can be appropriately selected from those exemplified for use in the positive electrode material layer 22 and used. The content of each component in the negative electrode material layer 24 may be the same as that in the prior art. The shape of the negative electrode material layer 24 may be the same as in the prior art. In particular, the sheet-like negative electrode material layer 24 is preferable from the viewpoint that the all-solid battery 100 can be easily configured. In this case, the thickness of the negative electrode material layer 24 is, for example, preferably 0.1 μm or more and 1 mm or less, and more preferably 1 μm or more and 100 μm or less. However, it is preferable to determine the thickness of the negative electrode material layer 24 so that the capacity of the negative electrode is larger than the capacity of the positive electrode.

1.2.5. Negative electrode current collector layer 25
The negative electrode current collector layer 25 may be made of metal foil, metal mesh or the like. In particular, metal foils are preferred. As a metal which comprises the negative electrode collector layer 25, Cu, Ni, Fe, Ti, Co, Zn, stainless steel etc. are mentioned. The negative electrode current collector layer 25 may have any coating layer on its surface for adjusting the contact resistance. For example, a coat layer or the like containing a conductive material and a resin. The thickness of the negative electrode current collector layer 25 is not particularly limited. The thickness of the negative electrode current collector 25 is not particularly limited. For example, the thickness is preferably 0.1 μm or more and 1 mm or less, and more preferably 1 μm or more and 100 μm or less.

  As shown in FIG. 3, it is preferable that the negative electrode current collector layer 25 be provided with a negative electrode current collection tab 25 a at a part of the outer edge thereof. The second current collector layer 12 and the negative electrode current collector layer 25 can be easily electrically connected by the tab 25a, and the negative electrode current collector layers 25 are easily electrically connected in parallel. be able to.

1.3. Arrangement and connection form of short circuit current dispersion body and power generation element 1.3.1. Arrangement of Power Generation Elements In the all-solid-state battery 100, the number of stacked power generation elements 20a and 20b is not particularly limited, and may be determined appropriately according to the output of the target battery. In this case, the plurality of power generation elements 20 may be stacked so as to be in direct contact with each other, or even if the plurality of power generation elements 20 are stacked via some layer (for example, insulating layer) or spacing (air layer) Good. From the viewpoint of improving the power density of the battery, as shown in FIG. 1, it is preferable that the plurality of power generation elements 20 be stacked so as to be in direct contact with each other. Further, as shown in FIGS. 1 and 3, it is preferable that the two power generation elements 20 a and 20 b share the negative electrode current collector 25. By doing this, the power density of the battery is further improved. Furthermore, as shown in FIG. 1, in the all-solid battery 100, it is preferable to make the stacking direction of the plurality of power generation elements 20 coincide with the stacking direction of the layers 21 to 25 in the power generation element 20. By so doing, restraint of the stacked battery 100 is facilitated, and the output density of the battery is further improved.

1.3.2. Electrical Connection of Power Generation Elements In the all-solid-state battery 100, a plurality of power generation elements are electrically connected in parallel. In such power generation elements connected in parallel, when one power generation element is shorted, electrons flow from the other power generation element to the one power generation element in a concentrated manner. That is, Joule heat is likely to increase at the time of battery short circuit. In other words, in the all-solid-state battery 100 including the plurality of power generation elements 20 connected in parallel in this manner, the effect of providing the short-circuit current dispersion 10 is more remarkable. A conventionally known member may be used as a member for electrically connecting the power generation elements. For example, as described above, the positive electrode current collector layer 21 is provided with the positive electrode current collector tab 21a, the negative electrode current collector layer 25 is provided with the negative electrode current collector tab 25a, and the power generation elements 20 are connected to each other through the tabs 21a and 25a. It can be electrically connected in parallel.

1.3.3. Electrical Connection Between Short-Circuit Current Dispersion and Power Generation Element In the all-solid-state battery 100, the first current collector layer 11 of the short-circuit current dispersion 10 is electrically connected to the positive electrode current collector layer 21 of the power generation element 20. The second current collector layer 12 of the short circuit current dispersion 10 is electrically connected to the negative electrode current collector layer 25 of the power generation element 20. Thus, by electrically connecting the short circuit current dispersion body 10 and the plurality of power generation elements 20, for example, at the time of short circuiting the short circuit current dispersion body 10 and some of the power generation elements (eg, power generation element 20a) The wraparound current from the power generation element (e.g., the power generation element 20b) can be distributed to the short circuit current dispersion 10. As a member for electrically connecting the short circuit current dispersion body 10 and the power generation element 20, a conventionally known member may be used. For example, as described above, the first current collector tab 11a is provided on the first current collector layer 11, and the second current collector tab 12a is provided on the second current collector layer 12, and the tabs 11a and 12a are provided. Can electrically connect the short circuit current dispersion body 10 and the power generation element 20.

1.3.4. Positional Relationship Between Short-Circuit Current Dispersion and Power Generation Element The short-circuit current dispersion 10 and the plurality of power generation elements 20 may be stacked on each other. In this case, the short circuit current dispersion 10 and the plurality of power generation elements 20 may be stacked directly, or may be stacked indirectly via another layer (such as an insulating layer or a heat insulating layer) as long as the above problems can be solved. You may In addition, as described above, the short circuit current dispersion 10 may be stacked outside the plurality of power generation elements 20, or may be stacked between the plurality of power generation elements 20, or a plurality of power generations. It may be laminated on both the outside of the element 20 and between the plurality of power generation elements 20. In particular, as shown in FIG. 1, in the case where the short circuit current dispersion 10 and the plurality of power generation elements 20 are stacked, the short circuit current dispersion 10 is preferably provided outside the plurality of power generation elements 20, It is more preferable that the short circuit current dispersion 10 be provided at least outside the plurality of power generation elements 20 in the stacking direction (the stacking direction of the layers in the plurality of power generation elements 20). As a result, at the time of nailing, the short circuit current dispersion 10 can be short-circuited earlier than the power generation element 20a and the like, and a wraparound current can be generated from the power generation element 20a and the like to the short circuit current dispersion 10 It is possible to suppress heat generation in the inside of 20a and the like.

  The short circuit of the battery due to the nail penetration is likely to occur because the nail is directed from the positive electrode current collector layer 21 of the power generation element 20a toward the negative electrode current collector layer 25 (or from the negative electrode current collector layer 25 to the positive electrode current collector layer 21) It is a case where it is stabbed. In this respect, in the all-solid-state battery 100, it is preferable that the nailing direction and the stacking direction of each layer coincide with each other. More specifically, as shown in FIG. 1, lamination of the positive electrode current collector layer 21, the positive electrode material layer 22, the solid electrolyte layer 23, the negative electrode material layer 24 and the negative electrode current collector layer 25 in the power generation elements 20 a and 20 b Direction, stacking direction of the plurality of power generation elements 20, stacking direction of the first current collector layer 11, the insulating layer 13 and the second current collector layer 12 in the short circuit current dispersion 10, and the short circuit current dispersion 10 And the plurality of power generation elements 20 are preferably in the same direction.

1.3.5. Relationship Between Size of Short-Circuit Current Dispersion and Power Generation Element In the all-solid-state battery 100, the short-circuit current dispersion 10 covers as much of the power generation element 20 as possible. It becomes easy to short-circuit the short circuit current dispersion 10 earlier than 20. From this viewpoint, for example, in the all solid battery 100, the outer edge of the short circuit current dispersion 10 is closer to the outer edge of the plurality of power generation elements 20 when viewed from the stacking direction of the short circuit current dispersion 10 and the plurality of power generation elements 20. Is preferably present outside. Alternatively, when the stacking direction of the plurality of power generation elements 20 and the stacking direction of the layers 21 to 25 are the same, the short circuit current dispersion when viewed from the stacking direction of the short circuit current dispersion 10 and the plurality of power generation elements 20 It is preferable that the outer edge 10 be present outside the outer edges of the positive electrode material layer 22, the electrolyte layer 23 and the negative electrode material layer 24. However, in this case, the first current collector layer 11 of the short circuit current dispersion 10 and the negative electrode current collector layer 25 of the power generation element 20 are prevented from short circuiting. That is, even if an insulator or the like is provided between the short circuit current dispersion 10 and the power generation element 20 to enlarge the short circuit current dispersion 10, the short circuit between the short circuit current dispersion 10 and the power generation element 20 can be prevented.

  On the other hand, from the viewpoint of further increasing the energy density of the battery and from the viewpoint of easily preventing the short circuit between the short circuit current dispersion 10 and the power generating element 20 described above, the short circuit current dispersion 10 may be made as small as possible. That is, from this point of view, in the all solid battery 100, the outer edge of the short circuit current dispersion 10 is inside the outer edge of the power generation element 20 when viewed from the stacking direction of the short circuit current dispersion 10 and the plurality of power generation elements 20. Is preferably present. Alternatively, in the case where the stacking direction of the plurality of power generation elements 20 is the same as the stacking direction of the layers 21 to 25 in the power generation element 20, when viewed from the stacking direction of the short circuit current dispersion 10 and the plurality of power generation elements 20, It is preferable that the outer edge of the short circuit current dispersion 10 be present inside the outer edges of the positive electrode material layer 22, the solid electrolyte layer 23 and the negative electrode material layer 24.

  As described above, in the all-solid-state battery 100, the short circuit current dispersion 10 due to the nailing and the sneak current from other power generation elements (for example, power generation element 20b) when the power generation elements (for example, power generation element 20a) Can be dispersed into the short circuit current dispersion 10. Here, in the all-solid-state battery 100, at least one of the first current collector layer 11 and the second current collector layer 12 of the short circuit current dispersion 10 is disposed on the side where the nail is to be punctured in the nail penetration test. The current collector layer to be formed is constituted by a plurality of metal foils. Thereby, the short circuit resistance of the short circuit current dispersion 10 can be stabilized at the time of the nail penetration test.

  Further, in the short circuit current dispersion 10 of the all solid battery 100, by forming the first current collector layer 11 with a plurality of metal foils, an effect of increasing the heat capacity of the short circuit current dispersion 10 can also be expected. That is, even if a large current flows into the short circuit current dispersion 10 at the time of nailing, heat generation of the short circuit current dispersion 10 can be suppressed, and deterioration of the battery material included in the power generation element 20 can be suppressed. Conceivable.

2. Method of Manufacturing All-Solid-State Battery The short-circuit current dispersion 10 is formed of an insulating layer 13 (for example, a metal foil) between the first current collector layer 11 (a plurality of metal foils) and the second current collector layer 12 (for example, a metal foil). For example, it can be easily produced by arranging a thermosetting resin sheet. For example, as shown in FIG. 2, the insulating layer 13 is disposed on at least one side of the second current collector layer 12, and the first side of the insulating layer 13 opposite to the second current collector layer 12 is The current collector layer 11 may be disposed. Here, in order to maintain the shape of the short circuit current dispersion 10, the layers may be bonded to each other using an adhesive, a resin, or the like. In this case, the adhesive or the like does not have to be applied to the entire surface of each layer, and may be applied to part of the surface of each layer.

The power generation element 20 can be manufactured by a known method. For example, the positive electrode material is wet coated on the surface of the positive electrode collector layer 21 and dried to form the positive electrode material layer 22, and the negative electrode material is wet coated on the surface of the negative electrode collector layer 25. By drying and drying, the negative electrode material layer 24 is formed, and the solid electrolyte layer 23 containing a solid electrolyte or the like is transferred between the positive electrode material layer 21 and the negative electrode material layer 24 and press-formed to be integrated. Element 20 can be made. The pressing pressure at this time is not particularly limited, but is preferably, for example, ² ton / cm ² or more. In addition, these preparation procedures are just an example to the last, and the power generation element 20 can be manufactured also by procedures other than this. For example, it is possible to form the positive electrode material layer or the like by a dry method instead of the wet method.

  While laminating the short circuit current dispersion 10 thus produced on a plurality of power generation elements 20, the tab 11a provided on the first current collector layer 11 is connected to the positive electrode current collector layer 21, The tab 12a provided in the second current collector layer 12 is connected to the negative electrode current collector layer 25, the tabs 21a of the positive electrode current collector layer 21 are connected, and the tabs 25a of the negative electrode current collector layer 25 are connected. Thus, the short-circuit current dispersion body 10 and the power generation element 20 can be electrically connected, and the plurality of power generation elements 20 can be electrically connected in parallel. An all-solid battery can be manufactured by vacuum-sealing the laminate thus electrically connected in a battery case such as a laminate film or a stainless steel can. Note that these preparation procedures are merely an example, and all-solid-state batteries can be prepared by other procedures.

  As mentioned above, the application of the manufacturing method of the conventional all-solid-state battery can manufacture easily the all-solid-state battery 100 of this indication.

3. Additional Matters In the above description, in the short-circuit current dispersion 10, the first current collector layer 11 electrically connected to the positive electrode current collector layer 21 of the power generation element 20 includes a plurality of metal foils. However, the all solid state battery of the present disclosure is not limited to this form. It is also possible that the second current collector layer 12 electrically connected to the negative electrode current collector layer 25 is disposed on the side where the nail is to be pierced during the nail penetration test. In this case, a plurality of metal foils are laminated at least in the second current collector layer 12 along the stacking direction of the first current collector layer 11, the insulating layer 13 and the second current collector layer 12. Just do it. The specific configuration of the case where the second current collector layer 12 is a laminate of a plurality of metal foils is the same as that of the first current collector layer 11 described above, and therefore, the detailed description here will be made here. I omit explanation.

  In the above description, although the form in which the short circuit current dispersion is configured by one first current collector layer, one insulating layer and one second current collector layer is described, the all solid of the present disclosure can be obtained. The battery is not limited to this form. The short-circuit current dispersion may be any one having an insulating layer between the first current collector layer and the second current collector layer, and the number of each layer is not particularly limited. Also in the case where a plurality of current collector layers are provided, as described above, at least the current collector layer disposed on the side where the nail is to be pierced in the nail penetration test is constituted of a plurality of metal foils.

  In the above description, only one short circuit current dispersion is provided outside the stacking direction of the plurality of power generation elements in the all solid battery, but the number of the short circuit current dispersions is not limited to this. . A plurality of short circuit current dispersions may be provided on the outside of the all solid state battery. In addition, the short circuit current dispersion may be provided between the plurality of power generation elements as well as the outside of the plurality of power generation elements.

  In the above description, the two power generation elements are shown to share one negative electrode current collector layer, but the all solid state battery of the present disclosure is not limited to this form. The power generation element only needs to function as a unit cell, and the positive electrode current collector layer, the positive electrode material layer, the solid electrolyte layer, the negative electrode material layer, and the negative electrode current collector layer may be stacked. For example, two power generation elements may share one positive current collector layer, or multiple power generation elements may independently exist without sharing current collector layers. Good.

  In the above description, although a form in which a plurality of power generation elements are stacked is shown, a certain degree of effect is achieved even in a form in which a plurality of power generation elements are not stacked in an all solid battery (a form consisting of only one unit cell). It is considered to be However, Joule heat due to a short circuit at the time of nailing or the like tends to be larger in a form in which a plurality of power generation elements are stacked than a form in which one power generation element is formed. That is, in the form in which a plurality of power generation elements are stacked, it can be said that the effect by providing the short circuit current dispersion becomes more remarkable.

  In the above description, it has been described that the current collection tab protrudes from the short circuit current dispersion body or the power generation element. However, the current collection tab may not be present in the all solid state battery of the present disclosure. For example, in the laminate of the short-circuit current dispersion and the power generation element, the outer edges of the plurality of current collector layers are made to project by using the current collector layer having a large area, and conduction is performed between the projected current collector layers. By sandwiching the material, it is possible to electrically connect the current collector layers without providing a tab. Alternatively, the current collector layers may be electrically connected to each other by conducting wires or the like instead of the tabs.

  In the above description, the all solid battery except the electrolyte battery was described. The technology of the present disclosure is considered to be applicable also to an electrolyte solution battery, but is considered to exert a remarkable effect when applied to an all solid battery. The all-solid-state battery has a smaller gap in the power generation element compared to the electrolyte battery, and the pressure applied to the power generation element is high when the nail penetrates the power generation element when nailing. Therefore, it is considered that the short circuit resistance of the power generation element is reduced, and a large amount of sneak current flows into some of the power generation elements. Furthermore, in the all-solid-state battery, in order to reduce internal resistance in the power generation element, a restraint pressure may be applied to the power generation element. In this case, the restraint pressure is applied in the stacking direction of the power generation element (the direction in which the positive electrode current collector layer is directed to the negative electrode current collector layer), and when nailing, the pressure by the nail and the restraint pressure are added to generate power. It is considered that since the positive electrode current collector layer and the negative electrode current collector layer are in contact with each other to cause a short circuit easily because the voltage is applied to the element, the short circuit resistance of the power generation element tends to be small. Therefore, it is considered that the effect of providing the short circuit current dispersion to disperse the wraparound current becomes remarkable. Furthermore, in the all-solid-state battery, when the nail penetrates the short circuit current dispersion at the time of nailing, the pressure applied to the short circuit current dispersion also increases. That is, how to properly contact the first current collector layer and the second current collector layer in a state where a high pressure is applied at the time of nailing to reduce the short circuit resistance of the short circuit current dispersion is a problem. It becomes. The technique of the present disclosure solves the problem. On the other hand, in the case of an electrolyte battery, the inside of the battery case is usually filled with the electrolyte, and each layer is immersed in the electrolyte so that the electrolyte is supplied to the gap between the layers. The pressure is reduced compared to the case of the all solid state battery. Therefore, the generation mechanism of the problem is different from that of the all solid battery, and the effect of providing the short circuit current dispersion is considered to be relatively smaller than that of the all solid battery.

  In addition, when the power generation elements are electrically connected in series via the bipolar electrode, when a nail is pierced to a part of the power generation elements, it wraps around from the other power generation element to the power generation element. It is considered that current flows. That is, it will turn around via a nail with high contact resistance, and the amount of current is small. In addition, when the power generation elements are electrically connected in series via the bipolar electrode, it is considered that the sneaking current is largest when all the power generation elements are pierced, but in such a case, the discharge of the power generation elements However, it is unlikely that the temperature of some of the power generating elements will rise locally. In this respect, it is considered that the effect of the short circuit current dispersion is reduced as compared with the case where the power generation elements are electrically connected in parallel. Therefore, it can be said that the technology of the present disclosure exerts a particularly remarkable effect in a battery in which power generation elements are electrically connected in parallel.

1. Preliminary Experiment With reference to the techniques disclosed in Patent Documents 1 to 4, in the case where the current collector layer of the short circuit current dispersion is formed using one metal foil, the stability of the short circuit resistance during the nail penetration test is confirmed.

1.1. Preparation of Short-Circuit Current Dispersion A single 15 μm thick aluminum foil (1N30 manufactured by UACJ) as the first current collector layer, and a 35 μm thick copper foil (manufactured by Furukawa Electric Co.) as the second current collector layer Using two sheets of a thermosetting polyimide resin film (25 μm thick, Kapton manufactured by Toray-DuPont Co., Ltd.) as an insulating layer between the first current collector layer and the second current collector layer, It fixed by the adhesive material and obtained the short circuit current dispersion which concerns on the comparative example 1. FIG. In addition, for convenience of the below-mentioned evaluation, the front and back of the obtained short circuit current dispersion shall be pinched | interposed by the insulating layer.

1.2. Evaluation of stability of short circuit resistance With respect to the short circuit current dispersion according to Comparative Example 1, the stability of the short circuit resistance of the short circuit current dispersion at the time of nailing was evaluated using a nail sticking test apparatus as shown in FIG. Specifically, the short circuit current dispersion was placed on an aluminum plate, and a DC power supply was connected to the tab of the short circuit current dispersion, while both surfaces of the short circuit current dispersion were restrained by a restraint jig. After restraint, set the set value of DC power supply as voltage (4.3 V) current (80 A), the side where nail is pierced (the nail piercing direction upstream side) is the first current collector layer, nail is pierced As the second current collector layer, the nail (φ 8 mm, tip angle 60 degrees) is pierced at a speed of 25 mm / sec and the current flows from the start to the end of the short circuit current dispersion The change in current was confirmed. The results are shown in FIG.

  As is apparent from the results shown in FIG. 5, when the short circuit current dispersion is configured with reference to the prior art, the current flowing to the short circuit current dispersion is not stable when nailing. It is considered that the contact between the first current collector layer and the second current collector layer is not stably maintained at the time of nailing to the short circuit current dispersion, whereby the short circuit resistance becomes unstable. . The contact between the first current collector layer and the second current collector layer is not stably maintained when the short circuit current dispersion is nailed, the current collector layer may be melted away due to Joule heat, or the nail may be broken. It is considered that the connection between the current collector layers is released or the like due to the temporal deformation of the current collector layer with the progress of From the above results, in order to stably maintain the contact between the first current collector layer and the second current collector layer when the short circuit current dispersion is nailed, the first current collection at the time of nailing can be performed. It is considered effective to increase the probability of contact between the current collector layer and the second current collector layer, and to increase the contact area between the first current collector layer and the second current collector layer.

2. Improvement of short circuit current dispersion and confirmation of effect Increase probability of contact between the first current collector layer and the second current collector layer at the time of nailing, and the first current collector layer and the second current collector In order to increase the contact area with the current collector layer, the configuration of the current collector layer of the short circuit current dispersion was improved. Specifically, the configuration of the current collector layer disposed on the side where the nail was to be pierced during the nail penetration test was changed.

2.1. Preparation of Short-Circuit Current Dispersion <Example 1>
A short-circuit current dispersion was obtained in the same manner as in Comparative Example 1 except that as the first current collector layer, a stack of seven aluminum foils (1N30 manufactured by UACJ, 15 μm thick) was used. The configuration of the short circuit current dispersion according to the first embodiment is shown in FIG.

Comparative Example 2
A short circuit current dispersion was obtained in the same manner as in Comparative Example 1 except that one aluminum foil (1N30) with a thickness of 100 μm was used as the first current collector layer. The configuration of the short circuit current dispersion according to Comparative Example 2 is shown in FIG.

2.2. Evaluation of stability of short-circuit resistance For each of the short-circuit current dispersions according to Example 1 and Comparative Example 2, stability of the short-circuit resistance of the short-circuit current dispersion at the time of nail penetration using a nail penetration testing device as shown in FIG. Was evaluated. Specifically, the short circuit current dispersion was placed on an aluminum plate, and a DC power supply was connected to the tab of the short circuit current dispersion, while both surfaces of the short circuit current dispersion were restrained by a restraint jig. The restraint pressure was the same as in Comparative Example 1. After restraint, set the setting value of DC power supply as voltage (4.3 V), current (245 A), and the side where the nail is pierced (upstream side) is the first current collector layer, the side from which the nail is pierced ( Using the second current collector layer as the second current collector layer, pierce the nail (φ 8 mm, tip angle 60 degrees) at a speed of 25 mm / sec, and check the change in current flowing in the short circuit current dispersion from the nail stabbing start to the end did. The results are shown in FIG.

As apparent from the results shown in FIG. 8, in the short-circuit current dispersion according to Comparative Example 2, a current of about 180 A flows immediately after the nail penetration, but almost no current flows after about 0.5 seconds. From the results of Comparative Example 1, even if the thickness of the first current collector layer is increased, it is difficult to increase the probability of contact between the first current collector layer and the second current collector layer at the time of nailing. It has been found that it is difficult to improve the contact between the first current collector layer and the second current collector layer.
On the other hand, in the short-circuit current dispersion according to Example 1, a current of about 180 A stably flowed immediately after the nail penetration. From the results of Example 1, by forming the current collector layer disposed on the side where the nail is pierced in the nail penetration test with a plurality of metal foils, the probability of contact between the current collector layers at the time of nail penetration is increased. It has been found that the contact area between the current collector layers can be increased, and the short circuit resistance (in particular, the contact resistance between the current collector layers) of the short circuit current dispersion at the time of nailing can be kept small.

  Further, in the short-circuit current dispersion according to the first embodiment, the current collector layer is thicker than the short-circuit current dispersion according to the first comparative example, and has a large heat capacity. That is, there is an advantage that the short circuit current dispersion hardly generates heat even if the sneaking current flows in.

  As described above, when the short-circuit current dispersion is provided together with the power generation element in the all-solid-state battery, a plurality of metal foils are used as the current collector layer disposed on the nail penetration side in the nailing test in the short-circuit current dispersion. It has become clear that the configuration makes it possible to keep the short circuit resistance of the short circuit current dispersion small during the nail penetration test and appropriately disperse the sneak current from the power generation element to the short circuit current dispersion.

3. Examination of thickness and number of metal foils in short circuit current dispersion 3.1. Preparation of Short-Circuit Current Dispersion <Examples 2 to 6, Reference Examples 1 to 3>
Comparative Example 1 except that aluminum foil having a thickness shown in Table 1 below (1N30, manufactured by Fukuda Foil & Powder Industries, Inc.) was used as the first current collector layer and the number shown in Table 1 below was used. A short circuit current dispersion was obtained in the same manner as in.

3.2. Evaluation of stability of short circuit resistance For each of the short circuit current dispersions according to Examples 1 to 6, Comparative Example 2 and Reference Examples 1 to 3, using the nail penetration test apparatus as shown in FIG. The stability of the short circuit resistance of the short circuit current dispersion at the time of nailing was evaluated. In addition, the average value (average current) of the current flowing in the short circuit current dispersion at the time of nailing was determined. The larger the average current, the better. The results are shown in Table 2 below.

  As is clear from the results shown in Table 2, in all of Examples 1 to 6 and Reference Examples 1 to 3, the average value of the current flowing through the short circuit current dispersion at the time of nail penetration was larger than that of Comparative Example 2. . That is, in the short-circuit current dispersion, by employing a laminate of a plurality of metal foils as a current collector layer disposed on the side where the nail is pierced at the time of nailing, the nailing to the short-circuit current dispersion is It can be seen that the contact between the first current collector layer and the second current collector layer is improved to reduce the short circuit resistance. Among them, when the thickness per sheet of the plurality of metal foils is 9 μm to 15 μm (Examples 1 to 6, Reference Examples 2 and 3), the first current collector layer and the second current collector layer It can be said that it is easy to further improve the contact property of In particular, when the thickness per sheet of the plurality of metal foils is 9 μm or more and 15 μm or less and the number of the plurality of metal foils is 4 or more and 7 or less (Examples 1 to 6), the first The short circuit resistance can be more stably lowered while the contact between the current collector layer and the second current collector layer is further improved.

  In the above embodiment, although a mode in which a plurality of aluminum foils are adopted in the current collector layer on the side where nails are pierced at the time of nail penetration test has been described, the type of metal foil is not limited to aluminum foil . The present inventor has confirmed that the same effect is observed in the case of metal foils other than aluminum foil.

4.1. When the type of metal foil is changed For example, the same effect can be recognized when copper foil is used instead of aluminum foil. Examples are shown below.

4.2. Preparation of Short-Circuit Current Dispersions <Examples 7 to 10, Comparative Example 3>
A short circuit was carried out in the same manner as in Comparative Example 1 except that the number of copper foils (manufactured by Furukawa Electric Co., Ltd.) having the thicknesses shown in Table 3 below was used as the first current collector layer. A current dispersion was obtained.

4.3. Evaluation of stability of short circuit resistance For each of the short circuit current dispersions according to Examples 7 to 10 and Comparative Example 3, the short circuit current at the time of the nail penetration using the nail penetration testing apparatus as shown in FIG. The stability of the short circuit resistance of the dispersion was evaluated. In addition, the average value (average current) of the current flowing in the short circuit current dispersion at the time of nailing was determined. The larger the average current, the better. The results are shown in Table 4 below.

  As is clear from the results shown in Table 4, although the thickness of the current collector layer as a whole is smaller in Example 7 than in Comparative Example 3, the short circuiting in Example 7 is more likely to occur than in Comparative Example 3. The average value of the current flowing through the current dispersion increased. That is, in the short-circuit current dispersion, by employing a laminate of a plurality of metal foils as a current collector layer disposed on the side where the nail is pierced at the time of nailing, the nailing to the short-circuit current dispersion is It can be seen that the contact between the first current collector layer and the second current collector layer is improved to reduce the short circuit resistance. When the number of copper foils was 4 to 7 as in Examples 8 to 10, the average value of the current further increased. That is, when the thickness per sheet of the plurality of metal foils is 9 μm or more and 15 μm or less and the number of the plurality of metal foils is 4 or more and 7 or less (Examples 8 to 10), the first The short circuit resistance can be more stably lowered while the contact between the current collector layer and the second current collector layer is further improved.

  The all-solid-state battery according to the present invention can be widely and suitably used from small power supplies for portable devices and the like to large power supplies for vehicles and the like.

10 Short-circuit current dispersion 11 First current collector layer (a plurality of metal foils)
11a first current collection tab 12 second current collector layer 12a second current collector tab 13 insulating layer 20a, 20b power generation element 21 positive electrode current collector layer 21a positive electrode current collector tab 22 positive electrode material layer 23 solid electrolyte layer 24 Anode material layer 25 Anode current collector layer 25a Anode current collector tab 100 all solid battery

Claims (5)

An all solid battery in which at least one short circuit current dispersion and a plurality of power generation elements are stacked,
In the short-circuit current dispersion, a first current collector layer, a second current collector layer, and an insulating layer provided between the first current collector layer and the second current collector layer Are stacked,
In the power generation element, a positive electrode current collector layer, a positive electrode material layer, a solid electrolyte layer, a negative electrode material layer, and a negative electrode current collector layer are stacked,
The first current collector layer is electrically connected to the positive electrode current collector layer;
The second current collector layer is electrically connected to the negative electrode current collector layer;
The plurality of power generation elements are electrically connected in parallel,
Among the first current collector layer and the second current collector layer, at least at least one of the plurality of metal foils is the first current collector layer disposed on the side where the nail is to be pierced in the nail penetration test. Are stacked along the stacking direction of the current collector layer, the insulating layer, and the second current collector layer,
All solid state battery. The short circuit current dispersion is stacked outside the plurality of power generation elements,
Among the first current collector layer and the second current collector layer, in at least the current collector layer disposed outside, a plurality of metal foils are the first current collector layer and the insulating layer. And the second current collector layer are laminated along the laminating direction,
The all solid state battery according to claim 1. Stacking direction of the positive electrode current collector layer, the positive electrode material layer, the solid electrolyte layer, the negative electrode material layer, and the negative electrode current collector layer in the power generation element;
Stacking direction of the plurality of power generation elements,
A stacking direction of the first current collector layer, the insulating layer, and the second current collector layer in the short circuit current dispersion;
Stacking direction of the short circuit current dispersion and the plurality of power generation elements,
Are in the same direction,
The all-solid-state battery of Claim 1 or 2. The thickness per one of the plurality of metal foils is 9 μm or more and 15 μm or less,
The all-solid-state battery of any one of Claims 1-3. The thickness per one of the plurality of metal foils is 9 μm or more and 15 μm or less,
The number of the plurality of metal foils is four or more and seven or less.
The all-solid-state battery of any one of Claims 1-3.