JP7000975B2 - All solid state battery - Google Patents

Description

The present application discloses an all-solid-state battery.

Patent Document 1 discloses a laminated polymer electrolyte battery provided with a short-circuit forming and heat dissipation promoting unit in which two metal plates are arranged on the outside of a laminated electrode group via an insulator. According to the battery disclosed in Patent Document 1, when the electrodes are short-circuited during a battery nailing test or the like, the voltage of the power generation element can be reduced by passing a short-circuit current through the short-circuit forming and heat dissipation promoting unit. It is considered that the heat generated by the unit or the like can be smoothly dissipated to the outside. Patent Documents 2 to 4 also disclose various techniques for suppressing heat generation due to an internal short circuit of a battery such as nail sticking.

Japanese Unexamined Patent Publication No. 2001-068156 Japanese Patent No. 6027262 Japanese Unexamined Patent Publication No. 2015-072835 Japanese Patent Application Laid-Open No. 2015-018710

In an all-solid-state battery in which multiple power generation elements are stacked and electrically connected in parallel, when the power generation elements are short-circuited by a nail piercing test, electrons flow from some power generation elements to other power generation elements (hereinafter, this). Is sometimes referred to as "wrap-around current"), which causes a problem that the temperature of some power generation elements rises locally. To solve these problems, a short-circuit current dispersion is provided separately from the power generation element, and in the nail piercing test, the short-circuit current dispersion is short-circuited together with some power generation elements, and the wraparound current from the power generation element with high short-circuit resistance is short-circuited. It is considered that it is possible to prevent the temperature of only some of the power generation elements from rising locally by distributing them not only to the power generation elements having a small resistance but also to the short circuit current dispersion having a small short circuit resistance (Fig. 9). ..

The short-circuit current dispersion can be composed of a first current collector layer, a second current collector layer, and an insulating layer provided between them. For example, as disclosed in Patent Documents 1 and 2, various resins may be used to form an insulating layer. Alternatively, as disclosed in Patent Document 2, the insulating layer may be formed by 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 formed of a metal foil as disclosed in Patent Documents 1 to 4. As a result, 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 during nailing. It also seems that the short-circuit current collector can be short-circuited by contacting with.

However, the present inventors have newly stated that when the short-circuit current dispersion is constructed by diverting the techniques disclosed in Patent Documents 1 to 4, the short-circuit resistance of the short-circuit current dispersion may not be stable at the time of nailing. I ran into a difficult task. If the short-circuit resistance of the short-circuit current dispersion is unstable, the above-mentioned wraparound current cannot be efficiently dispersed in the short-circuit current dispersion, and there is a possibility that the Joule heat generation of the power generation element cannot be suppressed.

The present application is an all-solid-state battery in which at least one short-circuit current dispersion and a plurality of power generation elements are laminated as one of means for solving the above-mentioned problems, and the first aspect of the short-circuit current dispersion is the present application. An insulating layer provided between the current collector layer, the second current collector layer, the first current collector layer, and the second current collector layer is laminated, and in the power generation element, the current generation element has a laminated body. A positive electrode 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 collector layer. The second collector layer is electrically connected to the negative electrode current collector layer, and a plurality of the power generation elements are electrically connected in parallel to each other. Of the electric body layer and the second current collector layer, at least in the current collector layer arranged on the side where the nail is inserted in the nail piercing test, a plurality of metal foils are formed on the first current collector layer. Discloses an all-solid-state battery in which the insulating layer and the second collector layer are laminated along the stacking direction.

The "nail piercing side" means the nail head side (upstream side in the nail piercing direction) after the nail piercing of the nail piercing test is completed. On the other hand, the "nail piercing side" means the nail tip side (downstream side in the nail piercing direction) after the nail piercing in the nail piercing test is completed.
"... in the current collector layer ... a plurality of metal foils are laminated" means, for example, in the form in which a plurality of metal foils are overlapped, or in the cross-sectional shape by folding one metal leaf. It may be in the form of laminated metal foils.

In the all-solid-state battery of the present disclosure, the short-circuit current dispersion is laminated on the outer side of 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 arranged on the 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, there are a plurality of the power generation elements in the stacking direction of the positive electrode 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. The stacking direction of the short-circuit current dispersion, the stacking direction of the first collector layer, the insulating layer, and the second 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 directions of the above are the same.

In the all-solid-state battery of the present disclosure, it is preferable that the thickness of each of the plurality of metal foils is 9 μm or more and 15 μm or less.

In the all-solid-state battery of the present disclosure, it is preferable that the thickness of each 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.

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, when the short-circuit current dispersion is nailed, the first collector layer is used. The contact with the second collector layer is not stably maintained, which makes the short-circuit resistance unstable. When the short-circuit current dispersion is nailed, the contact between the first current collector layer and the second current collector layer is not stably maintained because the current collector layer is melted due to Joule heat generation or the nail is nailed. It is considered that this is caused by the disconnection between the current collector layers due to the time-dependent deformation of the current collector layer with the progress of the above. In order to stably maintain contact between the first current collector layer and the second current collector layer when nailing the short-circuit current dispersion, the first current collector layer and the first current collector layer and the second current collector layer are required to be stably maintained during nailing. It can be said that it is effective to increase the probability of contact with the current collector layer 2 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, among the first current collector layer and the second current collector layer constituting the short-circuit current dispersion, in the current collector layer on the side where the nail is pierced in the nail piercing test. Multiple 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 project toward the other current collector layer, respectively, and one current collector layer and the other current collector layer. A plurality of contact points and contact surfaces are likely to be formed with the layer. That is, according to the all-solid-state battery of the present disclosure, when the short-circuit current dispersion is nailed, the contact property between the first current collector layer and the second collector layer is improved, and the short-circuit current dispersion is used. The short circuit resistance can be stabilized.

It is a schematic diagram for demonstrating the layer structure of the all-solid-state battery 100. It is a schematic diagram for demonstrating the layer structure of the short-circuit current dispersion body 10. (A) is an external perspective view, and (B) is a sectional view taken along line IIB-IIB. It is a schematic diagram for demonstrating the layer structure of a power generation element 20. (A) is an external perspective view, and (B) is a sectional view taken along line IIIB-IIIB. It is a schematic diagram for demonstrating the nail piercing test method for a short-circuit current dispersion. This is the result of confirming the stability of the short-circuit resistance of the short-circuit current dispersion in the nail piercing test with respect to Comparative Example 1. It is a schematic diagram for demonstrating the structure of the short-circuit current dispersion which concerns on Example 1. FIG. It is a schematic diagram for demonstrating the structure of the short-circuit current dispersion which concerns on Comparative Example 2. FIG. This is the result of confirming the stability of the short-circuit resistance of the short-circuit current dispersion in the nail piercing test with respect to Example 1 and Comparative Example 2. It is a schematic diagram for demonstrating the wraparound current generated at the time of nailing in an all-solid-state battery in which power generation elements are connected in parallel.

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

As shown in FIGS. 1 to 3, the all-solid-state battery 100 is formed by stacking at least one short-circuit current dispersion 10 and a plurality of power generation elements 20 (power generation elements 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 is laminated. 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 laminated. 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. It is connected, and a plurality of power generation elements are electrically connected in parallel. Here, in the all-solid-state battery 100, it is arranged at least on the side where the nail is pierced in the nail piercing test among the first current collector layer 11 and the second current collector layer 12 of the short-circuit current dispersion 10. In the current collector layer (corresponding to the first current collector layer 11 in FIG. 1), a plurality of metal foils form a first current collector layer 11, an insulating layer 13, and a second current collector. It is characterized in that it is laminated 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, the first current collector layer 11 and the second current collector layer 12. A layer 13 is provided. In the short-circuit current dispersion 10 having such a configuration, 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 come into contact with each other to reduce the electric resistance.

1.1.1. The current collector layer arranged on the nail piercing side in the nail piercing test First, the "current collector layer arranged on the nail piercing side in the nail piercing test" will be described. In an all-solid-state battery, when the short-circuit current dispersion is laminated between a plurality of power generation elements (that is, when the short-circuit current dispersion is sandwiched between the power generation element and the power generation element), the short-circuit current distribution is performed. Both the first current collector layer and the second current collector layer of the body can be "the current collector layer arranged on the side where the nail is inserted in the nail insertion test". Therefore, in this case, it is preferable that both the first current collector layer and the second current collector layer are composed of a plurality of metal foils.
On the other hand, as shown in FIG. 1, when the short-circuit current dispersion 10 is stacked outside the plurality of power generation elements 20, the first current collector layer 11 and the second current collector of the short-circuit current dispersion 10 are stacked. The current collector layer arranged on the outer side of the body layer 12 is the "current collector layer arranged on the side where the nail is inserted in the nail insertion test". Therefore, in this case, at least the current collector layer arranged on the outer side of the first current collector layer 11 and the second current collector layer 12 of the short-circuit current dispersion 10 (the first in FIG. 1). In (corresponding to the current collector layer 11 of the above), a 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. It is preferable to have.

In the all-solid-state battery 100, the first current collector layer 11 arranged on the side where the nail is inserted during the nail insertion test is composed of a plurality of metal foils. Examples of the metal constituting the metal foil include Cu, Ni, Al, Fe, Ti, Zn, Co, Cr, Au, Pt, stainless steel and the like. The metal leaf may have some layer on its surface for adjusting the contact resistance.

In the first current collector layer 11, the thickness per metal foil is not particularly limited, and may be a general thickness as a metal foil, but from the viewpoint of exerting a more remarkable effect, it may be used. The thickness of one metal foil is preferably 1 μm or more and 90 μm or less. The lower limit is more preferably 7 μm or more, further preferably 9 μm or more, and the upper limit is more preferably 20 μm or less, still more preferably 15 μm or less.

In the first current collector layer 11, the thickness of the layer as a whole is not particularly limited. Considering the volume energy density of the battery and the like, it is preferable to make the thickness of the first 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 that the thickness of the first current collector layer 11 as a whole is 20 μm or more and 2 mm or less. The lower limit is more preferably 30 μm or more, further 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, the upper limit is more preferably 20 or less, and even more preferably 7 or less.

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

11.2. In the all-solid-state battery 100, the second collector layer 12 arranged on the side where the nail is pierced in the nail piercing test is a metal leaf. Or a metal mesh or the like. Metal leaf is particularly preferable. Examples of the metal constituting the second 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 some layer on its surface for adjusting the contact resistance.

The thickness of the second current collector layer 12 is not particularly limited. For example, it 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 within such a range, the first current collector layer 11 and the second current collector layer 12 can be brought into contact with each other more appropriately at the time of nailing. It is possible to short-circuit the short-circuit current dispersion 10 more appropriately.

As shown in FIG. 2, the second current collector layer 12 includes a current collector tab 12a, which is electrically connected to the negative electrode current collector layer 25 of the power generation element 20 via the current collector tab 12a. It is preferable to have. The current collector tab 12a may be made of the same material as the second current collector layer 12, or may be made of a different material.

In the all-solid-state battery of the present disclosure, at least on the side where the nail is pierced in the nail piercing test, among the first current collector layer 11 and the second current collector layer 12 of the short-circuit current dispersion 10. The current collector layer to be arranged may be composed of a plurality of metal foils. Therefore, as described above, in addition to the form in which only the first current collector layer 11 is composed of a plurality of metal foils, both the first current collector layer 11 and the second current collector layer 12 are plural. It is also possible to form a form composed of the metal foil of.

11.3. Insulation layer 13
In the all-solid-state battery 100, the insulating layer 13 may be any as long as it insulates 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 more advantageous than the insulating layer made of an inorganic material from the viewpoint that the probability of short circuit occurrence due to cracking is low during normal use.

Examples of the organic material that can form the insulating layer 13 include various resins. For example, various thermoplastic resins and various thermosetting resins. In particular, super engineering plastics such as polyimide, polyamide-imide, polyetheretherketone, and polyphenylene sulfide are preferable. Generally, thermosetting resins have higher thermal stability than thermoplastic resins, and are hard and brittle. That is, when the insulating layer 13 is made of the heat-curable resin, the insulating layer 13 is easily broken when the short-circuit current dispersion 10 is nailed, and the first current collector layer 11 and the second collector layer 11 and the second collector layer 13 are easily broken. It is possible to prevent the insulating layer 13 from following the deformation of the current collector layer 12, and the first current collector layer 11 and the second current collector layer 12 can be brought into contact with each other more easily. Further, even if the temperature of the insulating layer 13 rises, thermal decomposition can be suppressed. From this point of view, the insulating layer 13 is preferably composed of a thermosetting resin sheet, and more preferably composed of a thermosetting polyimide resin sheet.

Examples of the inorganic material that can form the insulating layer 13 include various ceramics. For example, an inorganic oxide. The insulating layer 13 may be formed of a metal foil having an oxide film on the surface. For example, by forming an anodic oxide film on the surface of the aluminum foil by alumite treatment, an aluminum foil having an aluminum oxide film as an insulating layer on the surface can be obtained. In this case, the thickness of the aluminum oxide film is preferably 0.01 μm or more and 5 μm or less. 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, it 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 within such a range, the first current collector layer 11 and the second current collector layer 12 can be more appropriately insulated and the nails can be used during normal use of the battery. The short-circuit current dispersion 10 can be short-circuited by more appropriately conducting the first current collector layer 11 and the second current collector layer 12 by deformation due to external stress such as piercing.

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

1.2.1. Positive electrode current collector layer 21
The positive electrode current collector layer 21 may be formed of a metal foil, a metal mesh, or the like. Metal leaf is particularly preferable. Examples of the metal constituting the positive electrode current collector layer 21 include Ni, Cr, Au, Pt, Al, Fe, Ti, Zn, and stainless steel. The positive electrode current collector layer 21 may have some coat layer on its surface for adjusting the contact resistance. For example, a coat layer containing a conductive material and a resin. The thickness of the positive electrode current collector layer 21 is not particularly limited. For example, it 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 positive electrode current collector layer 21 is provided with a positive electrode current collector tab 21a on a part of the outer edge. The tab 21a allows the first current collector layer 11 and the positive electrode current collector layer 21 to be easily electrically connected, and the positive electrode current collector layers 21 to be easily electrically connected in parallel. be able to.

1.2.2. Positive electrode material 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 contained. As the active material, a known active material may be used. From 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 low potential is described later. Each can be used as a negative electrode active material. For example, when constituting a lithium ion battery, various positive electrode active materials such as lithium cobalt oxide, lithium nickel oxide, LiNi _1/3 Co _1/3 Mn _{1/3 O2} , lithium manganate, and spinel-based lithium compounds are used. 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 ionic conductivity is higher than that of the organic polymer electrolyte. This is also because it has excellent heat resistance as compared with the organic polymer electrolyte. Further, it is considered that the pressure applied to the power generation element 20 at the time of nailing becomes higher than that of the organic polymer electrolyte, and the effect of the all-solid-state battery 100 of the present disclosure becomes remarkable. Preferred inorganic solid electrolytes include oxide solids such as lithium lanthanum dilconate, LiPON, Li _{1 + X} Al _X Ge _2-X (PO ₄ ) ₃ , Li-SiO-based glass, and Li-Al-SO-based glass. Electrolyte; Li ₂ SP ₂ S ₅ , Li ₂ S-SiS ₂ , LiI-Li ₂ S-SiS ₂ , LiI-Si ₂ SP ₂ S ₅ , LiI-LiBr-Li ₂ SP ₂ S ₅ , LiI-Li ₂ SP _{2 S 5, LiI-Li 2 SP 2 O 5, LiI-Li 3 PO 4-P 2 S 5 , Li 2 SP 2 S 5 - GeS 2} and other sulfides A solid electrolyte can be exemplified. In particular, a sulfide solid electrolyte containing Li ₂ SP ₂ S ₅ is more preferable, and a sulfide solid electrolyte containing 50 mol% or more of Li ₂ SP ₂ S ₅ is even more preferable. Examples of the binder that can be contained in the positive electrode material layer 22 include butadiene rubber (BR), acrylate butadiene rubber (ABR), polyvinylidene fluoride (PVdF), and the like. Examples of the conductive auxiliary agent that can be contained in the positive electrode material 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 in the conventional case. The shape of the positive electrode material layer 22 may be the same as in the conventional case. In particular, the sheet-shaped positive electrode material layer 22 is preferable from the viewpoint that the all-solid-state battery 100 can be easily configured. In this case, the thickness of the positive electrode material layer 22 is preferably, for example, 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 further optionally contain a binder in addition to the solid electrolyte. The above-mentioned inorganic solid electrolyte is preferable as the solid electrolyte. The binder can be appropriately selected and used from various binders exemplified as those used for the positive electrode material layer 22. The content of each component in the solid electrolyte layer 23 may be the same as before. The shape of the solid electrolyte layer 23 may be the same as before. In particular, the sheet-shaped solid electrolyte layer 23 is preferable from the viewpoint that the all-solid-state battery 100 can be easily configured. In this case, the thickness of the solid electrolyte layer 23 is preferably, for example, 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 contained. As the active material, a known active material may be used. From 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 the above-mentioned positive electrode active material, and a substance showing a low potential is used. Each can be used as a negative electrode active material. For example, in the case of constituting a lithium ion battery, Si or Si alloy; carbon material such as graphite or hard carbon; various oxides such as lithium titanate; metallic lithium, lithium alloy or the like can be used as the negative electrode active material. The solid electrolyte, the binder and the conductive auxiliary agent can be appropriately selected and used from those exemplified as those used for the positive electrode material layer 22. The content of each component in the negative electrode material layer 24 may be the same as in the conventional case. The shape of the negative electrode material layer 24 may be the same as in the conventional case. In particular, the sheet-shaped negative electrode material layer 24 is preferable from the viewpoint that the all-solid-state battery 100 can be easily configured. In this case, the thickness of the negative electrode material layer 24 is preferably, for example, 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 formed of a metal foil, a metal mesh, or the like. Metal leaf is particularly preferable. Examples of the metal constituting the negative electrode current collector layer 25 include Cu, Ni, Fe, Ti, Co, Zn, and stainless steel. The negative electrode current collector layer 25 may have some coat layer on its surface for adjusting the contact resistance. For example, a coat layer 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, it 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 is provided with a negative electrode current collector tab 25a on a part of the outer edge. The tab 25a allows the second current collector layer 12 and the negative electrode current collector layer 25 to be easily electrically connected, and the negative electrode current collector layers 25 to be easily electrically connected in parallel. be able to.

1.3. Arrangement and connection form of short-circuit current dispersion 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 appropriately determined according to the output of the target battery. In this case, a plurality of power generation elements 20 may be laminated so as to be in direct contact with each other, or a plurality of power generation elements 20 may be laminated via some layer (for example, an insulating layer) or an interval (air layer). good. From the viewpoint of improving the output density of the battery, as shown in FIG. 1, it is preferable that the plurality of power generation elements 20 are laminated 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 20a and 20b share the negative electrode current collector 25. By doing so, the output density of the battery is further improved. Further, as shown in FIG. 1, in the all-solid-state battery 100, it is preferable that the stacking direction of the plurality of power generation elements 20 coincides with the stacking direction of the layers 21 to 25 in the power generation element 20. By doing so, the laminated battery 100 can be easily restrained, and the output density of the battery is further improved.

1.3.2. Electrical connection between power generation elements In the all-solid-state battery 100, a plurality of power generation elements are electrically connected in parallel. In the power generation elements connected in parallel in this way, when one power generation element is short-circuited, electrons flow from the other power generation elements to the one power generation element in a concentrated manner. That is, Joule heat generation tends to increase when the battery is short-circuited. In other words, in the all-solid-state battery 100 including the plurality of power generation elements 20 connected in parallel in this way, the effect of providing the short-circuit current dispersion 10 becomes more remarkable. As a member for electrically connecting the power generation elements to each other, a conventionally known member may be used. 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 via the tabs 21a and 25a. It can be electrically connected in parallel.

1.3.3. Electrical connection between the short-circuit current dispersion and the 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 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. By electrically connecting the short-circuit current dispersion 10 and the plurality of power generation elements 20 in this way, for example, when the short-circuit current dispersion 10 and some power generation elements (for example, the power generation element 20a) are short-circuited, the other The wraparound current from the power generation element (for example, the power generation element 20b) can be distributed to the short-circuit current disperser 10. As a member for electrically connecting the short-circuit current dispersion 10 and the power generation element 20, a conventionally known member may be used. For example, as described above, the first current collector layer 11 is provided with the first current collector tab 11a, the second current collector layer 12 is provided with the second current collector tab 12a, and the tabs 11a and 12a are provided. The short-circuit current dispersion 10 and the power generation element 20 can be electrically connected via the above.

1.3.4. Positional relationship between the short-circuit current dispersion and the power generation element The short-circuit current dispersion 10 and the plurality of power generation elements 20 may be laminated on each other. In this case, the short-circuit current dispersion 10 and the plurality of power generation elements 20 may be directly laminated, or indirectly laminated via another layer (insulation layer, heat insulating layer, etc.) within the range in which the above problems can be solved. You may. Further, as described above, the short-circuit current dispersion 10 may be stacked outside the plurality of power generation elements 20, may be stacked between the plurality of power generation elements 20, or may be laminated between the plurality of power generation elements 20. It may be laminated both on the outside of the element 20 and between the plurality of power generation elements 20. In particular, as shown in FIG. 1, when the short-circuit current dispersion 10 and the plurality of power generation elements 20 are laminated, it is preferable that the short-circuit current dispersion 10 is provided outside the plurality of power generation elements 20. It is more preferable that the short-circuit current dispersion 10 is provided at least outside the stacking direction (stacking direction of each layer in the plurality of power generation elements 20) than the plurality of power generation elements 20. As a result, the short-circuit current dispersion 10 can be short-circuited before the power generation element 20a or the like at the time of nailing, and can sneak from the power generation element 20a or the like to the short-circuit current dispersion 10 to generate a current, and further, the power generation element. It is possible to suppress heat generation inside 20a and the like.

A short circuit of the battery due to nail sticking is likely to occur when the nail moves 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). This is the case of being stabbed (towards 21). 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, 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 laminated in the power generation elements 20a and 20b. Direction, stacking direction of a plurality of power generation elements 20, stacking direction of the first current collector layer 11 and 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 stacking direction of the plurality of power generation elements 20 are preferably the same direction.

1.3.5. Relationship between the size of the short-circuit current dispersion and the power generation element In the all-solid-state battery 100, the short-circuit current dispersion 10 covers as many parts of the power generation element 20 as possible, so that a plurality of power generation elements are generated at the time of nailing. It becomes easy to short-circuit the short-circuit current dispersion 10 before 20. From this point of view, for example, in the all-solid-state battery 100, the outer edge of the short-circuit current dispersion 10 is larger than 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 on the outside. Alternatively, when the stacking direction of the plurality of power generation elements 20 and the stacking direction of each layer 21 to 25 are the same, the short-circuit current dispersion is 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 10 is outside the outer edge of the positive electrode material layer 22, the electrolyte layer 23, and the negative electrode material layer 24. However, in this case, the first 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 and the short-circuit current dispersion 10 is enlarged, it is possible to prevent the short-circuit current dispersion 10 and the power generation element 20 from being short-circuited.

On the other hand, the short-circuit current dispersion 10 may be made as small as possible from the viewpoint of further increasing the energy density of the battery and from the viewpoint of easily preventing a short circuit between the short-circuit current dispersion 10 and the power generation element 20 described above. That is, from this point of view, in the all-solid-state 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. It is preferable to be present in. Alternatively, when the stacking direction of the plurality of power generation elements 20 and the stacking direction of each layer 21 to 25 in the power generation element 20 are the same, 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 is present inside the outer edge 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, when the short-circuit current dispersion 10 and a part of the power generation element (for example, the power generation element 20a) are short-circuited by nail sticking, the wraparound current from another power generation element (for example, the power generation element 20b) Can be dispersed in the short-circuit current disperser 10. Here, in the all-solid-state battery 100, it is arranged at least on the side where the nail is pierced in the nail piercing test among the first current collector layer 11 and the second current collector layer 12 of the short-circuit current dispersion 10. The current collector layer to be formed is composed of a plurality of metal foils. As a result, the short-circuit resistance of the short-circuit current dispersion 10 can be stabilized during the nail piercing test.

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

2. 2. Method for manufacturing an all-solid-state battery The short-circuit current dispersion 10 has an insulating layer 13 (for example, a metal foil) between a first current collector layer 11 (a plurality of metal foils) and a second current collector layer 12 (for example, a metal foil). For example, it can be easily manufactured by arranging a thermosetting resin sheet). For example, as shown in FIG. 2, the insulating layer 13 is arranged on at least one surface of the second current collector layer 12, and the first is further arranged on the surface of the insulating layer 13 opposite to the second current collector layer 12. The current collector layer 11 may be arranged. Here, in order to maintain the shape of the short-circuit current dispersion 10, each layer may be bonded to each other using an adhesive, a resin, or the like. In this case, the adhesive or the like does not need to be applied to the entire surface of each layer, but may be applied to a 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 layer 22 is formed by wet-coating and drying the positive electrode material on the surface of the positive electrode current collector layer 21, and the negative electrode material is wet-coated on the surface of the negative electrode current collector layer 25. The negative electrode material layer 24 is formed by drying the electrodes, and the solid electrolyte layer 23 containing the solid electrolyte and the like is transferred between the positive electrode material layer 21 and the negative electrode material layer 24, and the solid electrolyte layer 23 is press-molded and integrated to generate power. The element 20 can be made. The press pressure at this time is not particularly limited, but is preferably 2 ton / cm ² or more, for example. It should be noted that these manufacturing procedures are merely examples, and the power generation element 20 can be manufactured by other procedures. For example, it is also possible to form a positive electrode material layer or the like by a dry method instead of the wet method.

The short-circuit current dispersion 10 thus produced is laminated on the plurality of power generation elements 20, and 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 on the current collector layer 12 of 2 is connected to the negative electrode current collector layer 25, the tabs 21a of the positive electrode current collector layer 21 are connected to each other, and the tabs 25a of the negative electrode current collector layer 25 are connected to each other. By doing so, the short-circuit current dispersion 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-state battery can be manufactured by vacuum-sealing the electrically connected laminate in a battery case such as a laminated film or a stainless steel can. It should be noted that these manufacturing procedures are merely examples, and an all-solid-state battery can be manufactured by other procedures.

As described above, the all-solid-state battery 100 of the present disclosure can be easily manufactured by applying the conventional all-solid-state battery manufacturing method.

3. 3. Supplementary Provisions In the above description, in the short-circuit current dispersion 10, a form in which 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 will be described. However, the all-solid-state battery of the present disclosure is not limited to this form. There may be a form in which the second current collector layer 12 electrically connected to the negative electrode current collector layer 25 is arranged on the side where the nail is inserted during the nail insertion test. In this case, at least in the second current collector layer 12, a 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. Just do it. The specific configuration when the second current collector layer 12 is a laminated body of a plurality of metal foils is the same as the case of the first current collector layer 11 described above, and thus is detailed here. The explanation is omitted.

In the above description, the form in which the short-circuit current dispersion is formed by one first current collector layer, one insulating layer, and one second current collector layer has been shown, but the all-solid-state battery of the present disclosure has been described. The battery is not limited to this form. The short-circuit current dispersion may have 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. Even when a plurality of current collector layers are provided, at least the current collector layer arranged on the side where the nail is inserted at the time of the nail piercing test shall be composed of a plurality of metal foils.

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

In the above description, the mode in which the two power generation elements share one negative electrode current collector layer has been shown, but the all-solid-state battery of the present disclosure is not limited to this mode. The power generation element may be any as long as it functions as a cell, and it is sufficient that 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 are laminated. For example, two power generation elements may share one positive electrode current collector layer, or a plurality of power generation elements may exist independently without sharing the current collector layer. good.

In the above description, a form in which a plurality of power generation elements are stacked is shown, but a certain effect can be achieved even in a form in which a plurality of power generation elements are not stacked in an all-solid-state battery (a form consisting of only one cell). It is thought that it will be done. However, Joule heat generation due to a short circuit such as when nailing is likely to be larger in a form in which a plurality of power generation elements are laminated than in a form consisting of one power generation element. That is, it can be said that the effect of providing the short-circuit current dispersion becomes more remarkable in the form in which a plurality of power generation elements are laminated.

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

In the above description, the all-solid-state battery excluding the electrolytic solution-based battery is shown. Although the technique of the present disclosure may be applicable to an electrolytic solution-based battery, it is considered to exert a remarkable effect when applied to an all-solid-state battery. The all-solid-state battery has a smaller gap in the power generation element than the electrolyte-based battery, and the pressure applied to the power generation element is high when the nail penetrates the power generation element when the nail is pierced. Therefore, it is considered that the short-circuit resistance of the power generation element becomes small and a large amount of wraparound current flows into some power generation elements. Further, in the all-solid-state battery, a restraining pressure may be applied to the power generation element in order to reduce the internal resistance in the power generation element. In this case, a constraining pressure is applied in the stacking direction of the power generation elements (the direction in which the positive electrode current collector layer faces the negative electrode current collector layer), and when the nail is pierced, the pressure due to the nail and the restraining pressure are added to generate power. Since it is applied to the element, it is considered that the positive electrode current collector layer and the negative electrode current collector layer are likely to come into contact with each other to cause a short circuit, and the short circuit resistance of the power generation element is likely to be reduced. Therefore, it is considered that the effect of providing the short-circuit current disperser to disperse the wraparound current becomes remarkable. Further, in the all-solid-state battery, when the nail penetrates the short-circuit current dispersion during nail piercing, the pressure applied to the short-circuit current dispersion also increases. That is, the problem is how to properly contact the first current collector layer and the second current collector layer in a state where high pressure is applied at the time of nailing to reduce the short-circuit resistance of the short-circuit current dispersion. Will be. The above-mentioned technique of the present disclosure solves the problem. On the other hand, in an electrolytic solution-based battery, the inside of a battery case is usually filled with an electrolytic solution, each layer is immersed in the electrolytic solution, and the electrolytic solution is supplied to the gap between the layers, and the electrolytic solution is applied by a nail at the time of nail piercing. The pressure is smaller than that of the all-solid-state battery. Therefore, it is considered that the mechanism of occurrence of the problem is different from that of the all-solid-state battery, and the effect of providing the short-circuit current dispersion is relatively smaller than that of the all-solid-state battery.

When the power generation elements are electrically connected in series via a bipolar electrode, if a nail is inserted into some of the power generation elements, the other power generation elements wrap around to the part of the power generation elements via the nail. It is thought that an electric current flows. That is, it wraps around through a nail having high contact resistance, and the amount of current is small. In addition, when the power generation elements are electrically connected in series via bipolar electrodes, it is considered that the wraparound current becomes the largest when all the power generation elements are pierced by nails. In such a case, the power generation elements are discharged. It is considered that the temperature of some power generation elements has already progressed sufficiently, and it is unlikely that the temperature of some power generation elements will rise locally. In this respect, it is considered that the effect of the short-circuit current dispersion is smaller than that in the case where the power generation elements are electrically connected in parallel. Therefore, it can be said that the technique of the present disclosure exerts a particularly remarkable effect in a battery in which power generation elements are electrically connected in parallel.

1. 1. Preliminary experiment With reference to the techniques disclosed in Patent Documents 1 to 4, the stability of the short-circuit resistance during the nail piercing test was determined when the current collector layer of the short-circuit current dispersion was constructed using one metal foil. confirmed.

1.1. Fabrication of short-circuit current dispersion One aluminum foil (UACJ, 1N30) with a thickness of 15 μm was used as the first current collector layer, and a copper foil with a thickness of 35 μm (Furukawa Electric Co., Ltd.) was used as the second current collector layer. Two thermosetting polyimide resin films (thickness 25 μm, Capton manufactured by Toray Dupont Co., Ltd.) were sandwiched between the first current collector layer and the second current collector layer as an insulating layer. It was fixed with an adhesive to obtain a short-circuit current dispersion according to Comparative Example 1. For convenience of evaluation described later, the front and back surfaces of the obtained short-circuit current dispersion are sandwiched between insulating layers.

1.2. Evaluation of stability of short-circuit resistance For the short-circuit current dispersion according to Comparative Example 1, the stability of the short-circuit resistance of the short-circuit current dispersion during nail piercing was evaluated using a nail piercing test device as shown in FIG. Specifically, the short-circuit current dispersion was installed on an aluminum plate, and a DC power supply was connected to the tab of the short-circuit current dispersion, while both sides of the short-circuit current dispersion were constrained by a restraint jig. After restraint, the set value of the DC power supply is set to voltage (4.3V) and current (80A), and the side where the nail is inserted (upstream side in the nail insertion direction) is the first collector layer, and the nail is inserted. With the side (downstream side in the nail piercing direction) as the second collector layer, the nail (φ8 mm, tip angle 60 degrees) is pierced at a speed of 25 mm / sec and flows to the short-circuit current dispersion from the start to the end of the nail piercing. The change in current was confirmed. The results are shown in FIG.

As is clear from the results shown in FIG. 5, when the short-circuit current dispersion is configured with reference to the prior art, the current flowing through the short-circuit current dispersion is not stable at the time of nailing. It is probable that the contact between the first current collector layer and the second current collector layer was not stably maintained when the short-circuit current dispersion was nailed, and as a result, the short-circuit resistance became unstable. .. When the short-circuit current dispersion is nailed, the contact between the first current collector layer and the second current collector layer is not stably maintained because the current collector layer is melted due to Joule heat generation or the nail is nailed. It is considered that this is caused by the disconnection between the current collector layers due to the time-dependent deformation of the current collector layer with the progress of the above. From the above results, in order to stably maintain the contact between the first current collector layer and the second current collector layer when nailing the short-circuit current dispersion, the first current collector is collected at the time of nailing. It is considered effective to increase the probability that the current collector layer and the second current collector layer come into contact with each other, and to increase the contact area between the first current collector layer and the second current collector layer.

2. 2. Improvement of short-circuit current dispersion and confirmation of effect Increase the probability that the first current collector layer and the second current collector layer come into contact with each other at the time of nailing, and increase the probability that the first current collector layer and the second current collector layer come into contact with each other. The configuration of the current collector layer of the short-circuit current dispersion was improved with the aim of increasing the contact area with the electric body layer. Specifically, the configuration of the current collector layer arranged on the side where the nail is inserted during the nail insertion test was changed.

2.1. Fabrication 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 seven aluminum foils (manufactured by UACJ Corporation, 1N30) having a thickness of 15 μm were used as the first current collector layer. FIG. 6 shows the configuration of the short-circuit current dispersion according to the first embodiment.

<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) having a thickness of 100 μm was used as the first current collector layer. FIG. 7 shows the configuration of the short-circuit current dispersion according to Comparative Example 2.

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, the stability of the short-circuit resistance of the short-circuit current dispersion during nail piercing using a nail piercing test device as shown in FIG. Was evaluated. Specifically, the short-circuit current dispersion was installed on an aluminum plate, and a DC power supply was connected to the tab of the short-circuit current dispersion, while both sides of the short-circuit current dispersion were constrained by a restraint jig. The restraining pressure was the same as in Comparative Example 1. After restraint, the set values of the DC power supply are set to voltage (4.3V) and current (245A), and the side where the nail is inserted (upstream side) is the first collector layer and the side where the nail is inserted (the side where the nail is inserted). (Downstream side) is used as the second collector layer, and a nail (φ8 mm, tip angle 60 degrees) is pierced at a speed of 25 mm / sec, and the change in the current flowing through the short-circuit current dispersion from the start to the end of nail piercing is confirmed. did. The results are shown in FIG.

As is clear 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 nailing, 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 that the first current collector layer and the second current collector layer come into contact with each other at the time of nailing. Therefore, it was found that it is difficult to improve the contact property between the first current collector layer and the second current collector layer.
On the other hand, in the short-circuit current dispersion according to the first embodiment, a current of about 180 A was stably flowed immediately after the nail was pierced. From the results of Example 1, by forming the current collector layer arranged on the side where the nail is inserted in the nail insertion test with a plurality of metal foils, the probability that the current collector layers come into contact with each other at the time of nail insertion is increased. It was found that the contact area between the collector layers can be increased, and the short-circuit resistance of the short-circuit current dispersion at the time of nailing (particularly the contact resistance between the collector layers) can be kept small.

Further, the short-circuit current dispersion according to the first embodiment has a thicker current collector layer and a larger heat capacity than the short-circuit current dispersion according to the comparative example 1. That is, there is an advantage that the short-circuit current dispersion is unlikely to generate heat even if a wraparound current flows in.

As described above, when a short-circuit current dispersion is provided together with a power generation element in an all-solid-state battery, the collector layer arranged on the side where the nail is inserted during the nail insertion test in the short-circuit current dispersion is made of a plurality of metal foils. It was clarified that the short-circuit resistance of the short-circuit current dispersion can be kept small during the nail piercing test, and the wraparound current can be appropriately distributed from the power generation element to the short-circuit current dispersion.

3. 3. Examination of the thickness and number of metal foils in the short-circuit current dispersion 3.1. Fabrication of short-circuit current dispersion <Examples 2 to 6, Reference Examples 1 to 3>
Comparative Example 1 except that an aluminum foil (manufactured by Fukuda Foil Powder Industry Co., Ltd., 1N30) having the thickness shown in Table 1 below was used as the first current collector layer in a stacked number as shown in Table 1 below. A short-circuit current dispersion was obtained in the same manner as above.

3.2. Stability evaluation of short-circuit resistance For each of the short-circuit current dispersions according to Examples 1 to 6, Comparative Examples 2 and Reference Examples 1 to 3, the method described above was performed using a nail piercing test apparatus as shown in FIG. The stability of the short-circuit resistance of the short-circuit current dispersion during nailing was evaluated. In addition, the average value (mean current) of the current flowing through the short-circuit current dispersion at the time of nailing was obtained. It can be said that the larger the average current, the more preferable. The results are shown in Table 2 below.

As is clear from the results shown in Table 2, the average value of the current flowing through the short-circuit current dispersion during nailing was larger in both Examples 1 to 6 and Reference Examples 1 to 3 than in Comparative Example 2. .. That is, in the short-circuit current dispersion, by adopting a laminated body of a plurality of metal foils as the current collector layer arranged on the side where the nail is pierced at the time of nail piercing, when the short-circuit current dispersion is pierced with a nail, the first It can be seen that the contact property between the current collector layer 1 and the second collector layer is improved and the short-circuit resistance is lowered. Above all, when the thickness per sheet of the plurality of metal foils is 9 μm or more and 15 μm or less (Examples 1 to 6, Reference Examples 2 and 3), the first current collector layer and the second current collector layer are used. It can be said that it is easy to further improve the contact property of. In particular, when the thickness of each 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 method is used. The short-circuit resistance can be lowered more stably while further improving the contact property between the current collector layer and the second current collector layer.

In the above embodiment, a mode in which a plurality of aluminum foils are used in the current collector layer on the side where the nail is inserted during the nail insertion test has been described, but the type of the metal foil is not limited to the aluminum foil. .. The present inventor has confirmed that the same effect is observed in the case of a metal foil other than the aluminum foil.

4.1. When the type of metal foil is changed For example, the same effect is observed when copper foil is used instead of aluminum foil. Hereinafter, examples will be shown.

4.2. Fabrication of short-circuit current dispersion <Examples 7 to 10, Comparative Example 3>
Short-circuited in the same manner as in Comparative Example 1 except that a copper foil (manufactured by Furukawa Electric Co., Ltd.) having a thickness shown in Table 3 below was used as the first current collector layer. A current dispersion was obtained.

4.3. Stability evaluation 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 nail piercing was performed by the above-mentioned method using a nail piercing test apparatus as shown in FIG. The stability of the short-circuit resistance of the dispersion was evaluated. In addition, the average value (mean current) of the current flowing through the short-circuit current dispersion at the time of nailing was obtained. It can be said that the larger the average current, the more preferable. 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 thinner in Example 7 than in Comparative Example 3, Example 7 is short-circuited at the time of nailing than Comparative Example 3. The average value of the current flowing through the current dispersion has increased. That is, in the short-circuit current dispersion, by adopting a laminated body of a plurality of metal foils as the current collector layer arranged on the side where the nail is pierced at the time of nail piercing, when the short-circuit current dispersion is pierced with a nail, the first It can be seen that the contact property between the current collector layer 1 and the second collector layer is improved and the short-circuit resistance is lowered. Further, when the number of copper foils was 4 to 7 as in Examples 8 to 10, the average value of the current was further increased. That is, when the thickness of each 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 lowered more stably while further improving the contact property between the current collector layer and the second current collector layer.

The all-solid-state battery according to the present invention can be widely and suitably used from a small power source for mobile devices to a large power source for mounting on a vehicle.

10 Short-circuit current dispersion 11 First current collector layer (multiple metal foils)
11a 1st current collector tab 12 2nd current collector layer 12a 2nd current collector tab 13 Insulation 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 Negative electrode material layer 25 Negative electrode current collector layer 25a Negative electrode current collector tab 100 All-solid-state battery

Claims (5)

An all-solid-state battery in which at least one short-circuit current dispersion and a plurality of power generation elements are laminated.
In the short-circuit current dispersion, the insulating layer provided between the first current collector layer, the second current collector layer, the first current collector layer, and the second current collector layer is formed. It is laminated and
In the power generation element, a positive electrode 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.
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, and the power generation elements are electrically connected in parallel.
Of the first current collector layer and the second current collector layer, at least in the current collector layer arranged on the side where the nail is inserted in the nail piercing test, the plurality of metal foils are the first. The current collector layer, the insulating layer, and the second current collector layer are laminated along the stacking direction.
The thickness of each 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 4 or more and 7 or less.
All-solid-state battery. The short-circuit current dispersion is laminated on the outer side of the plurality of power generation elements.
Of the first current collector layer and the second current collector layer, at least in the current collector layer arranged on the outside, a plurality of metal foils form the first current collector layer and the insulating layer. And the second collector layer are laminated along the stacking direction.
The all-solid-state battery according to claim 1. The 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,
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 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 according to claim 1 or 2. The insulating layer is made of a thermosetting resin sheet.
The all-solid-state battery according to any one of claims 1 to 3. The insulating layer is made of a thermosetting polyimide resin sheet.
The all-solid-state battery according to any one of claims 1 to 3.

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