JP2018107003A - All-solid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hermetic type all-solid battery in which an all-solid battery laminate is uniformity bound.SOLUTION: An all-solid battery 100 in which an all-solid battery laminate 15 is sealed and housed in an outer can 20, is an all-solid battery 100, in which the all-solid battery laminate 15 includes one or more of a battery element 10 in which a negative electrode collector layer 1, a negative activation layer 2, a solid electrolyte layer 3, a positive activation layer 4, and a positive electrode collector layer 5 are laminated in this order, the outer can 20 includes a bottom surface part 20a, a side surface part 20b, a curving surface part 20c connecting the bottom surface 20a and the side surface part 20b, and an upper surface part opposite to the bottom surface part 20a (not shown). The all-solid battery laminate 15 is housed in the outer can 20 so that the lamination direction is vertical to the bottom surface part 20a of the outer can 20, and the curving surface part 20c of the outer can 20 is positioned on a side surface part 20b side from an overlapping region A with the negative activation layer 2 and the positive activation layer 4 when the all-solid battery 100 is observed from the lamination direction of the all-solid battery laminate 15.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an all-solid battery in which an all-solid battery stack is hermetically stored in an outer can.

  An all-solid battery in which a solid all-solid battery stack is hermetically stored in an outer can is known.

  For example, Patent Document 1 discloses a battery in which a power generation element having a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte is housed in an exterior member, and the exterior member is a metal exterior can; In addition, it is described that an all solid polymer solid electrolyte may be used instead of the electrolytic solution.

JP 2004-139916 A

  In order to advance a battery reaction in an all-solid battery using an all-solid battery stack, it is necessary to restrain the stack. The same applies to a sealed all-solid battery in which the all-solid battery stack is hermetically housed in an outer can.

  However, in a sealed type all-solid-state battery, depending on the structure, shape, etc. of the outer can used, the laminate may not be uniformly restrained, and the desired charge / discharge characteristics may not be exhibited.

  The present invention has been made to improve the above problems. Accordingly, an object of the present invention is to provide a sealed all-solid battery in which the all-solid battery stack is uniformly restrained.

The above object of the present invention is to
An all-solid battery in which an all-solid battery stack is hermetically stored in an outer can,
The all-solid battery laminate includes one or more battery elements in which a negative electrode current collector layer, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector layer are laminated in this order,
The outer can has a bottom surface portion, a side surface portion, a curved surface portion connecting the bottom surface portion and the side surface portion, and an upper surface portion facing the bottom surface portion,
The all-solid battery laminate is housed in the outer can so that its stacking direction is perpendicular to the bottom surface of the outer can, and the curved surface portion of the outer can is used to remove the all-solid battery from the entire can. This is achieved by the all solid state battery located on the side of the side surface with respect to the overlapping region of the negative electrode active material layer and the positive electrode active material layer when observed from the stacking direction of the solid battery laminate.

  In the all solid state battery of the present invention, in the all solid state battery stack that is hermetically housed in the outer can, the overlapping region between the negative electrode active material layer and the positive electrode active material layer that contributes to charge / discharge is uniformly restricted. Therefore, the all-solid-state battery of the present invention can exhibit the desired charge / discharge characteristics without deficiency.

FIG. 1 is a schematic cross-sectional view for explaining the structure of the all solid state battery of the present invention. FIG. 2 is an enlarged view of the vicinity of the curved surface of the outer can in the all solid state battery of FIG.

<All solid battery>
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view for explaining the structure of the all solid state battery of the present invention.

  The all solid state battery 100 in FIG. 1 has an all solid state battery stack 15. The all-solid battery stack 15 includes an all-solid battery element 10 in which a negative electrode current collector layer 1, a negative electrode active material layer 2, a solid electrolyte layer 3, a positive electrode active material layer 4, and a positive electrode current collector layer 5 are laminated in this order. However, the negative electrode current collector layer 1 and the positive electrode current collector layer 5 are shared, and three layers are stacked with the stacking order being the reverse direction.

  The all-solid-state battery laminate 15 has an overlapping region A where the negative electrode active material layer 2 and the positive electrode active material layer 4 overlap, and the negative electrode active material layer 2 and the positive electrode active material layer 4 when observed from the stacking direction. A non-overlapping non-overlapping region B.

  The all-solid battery stack 15 is hermetically housed in the outer can 20. The outer can 20 includes a bottom surface portion 20a, a side surface portion 20b, a curved surface portion 20c that connects the bottom surface portion 20a and the side surface portion 20b, and a top surface portion (not shown) that faces the bottom surface portion 20a.

  In the outer can 20, the bottom surface portion 20 a, the side surface portion 20 b, and the top surface portion may be planar. The angle formed by the bottom surface portion 20a and the side surface portion 20b is typically 90 degrees. The bottom surface portion 20a and the top surface portion (not shown) are typically parallel.

  The all-solid-state battery stack 15 is housed in the outer can 20 so that the stacking direction is perpendicular to the bottom surface portion 20 a of the outer can 20. The curved surface portion 20c of the outer can 20 has the negative electrode active material layer 2 and the positive electrode active material layer 4 in the all solid battery stack 15 when the all solid battery 100 is observed from the stacking direction of the all solid battery stack 15. It is located on the side surface portion 20b side of the overlapping region A.

  In the all solid state battery 100 of the present embodiment, the curved surface portion 20c of the outer can 20 is arranged on the side surface portion 20b side of the overlap region A of the all solid state battery stack 15 so that the entire overlap region A is uniform. Can be restrained. Therefore, since the battery reaction between the layers in the all-solid battery laminate 15 proceeds appropriately, the expected charge / discharge characteristics can be expressed.

  On the other hand, in the non-overlapping region B in the all-solid battery stack 15 in the all-solid battery 100 of the present embodiment, the inter-layer battery reaction is not performed, and thus does not contribute to charge / discharge of the all-solid battery 100. Lacks the premise to demand uniformity. Therefore, the curved surface portion 20c of the outer can 20 may be located on the side surface portion 20b side with respect to the non-overlapping region B of the all-solid battery stack 15, or may partially overlap with the region B. .

  The curved surface portion 20c of the outer can 20 is located on the side surface portion 20b side with respect to the overlapping region A. When the outer can 20 is observed from a direction perpendicular to the stacking direction of the all-solid battery stack 15, the starting point of the curved surface portion 20c. Is located on the side surface 20b side with respect to the overlapping region A. The “starting point of the curved surface portion 20 c” is a straight line in which the shape of the outer can 20 is defined by the bottom surface portion 20 a when the outer can 20 is observed from a direction perpendicular to the stacking direction of the all-solid battery stack 15. The point that stands up from.

  In FIG. 2, the enlarged view of the curved surface part vicinity of an exterior can in the all-solid-state battery of this embodiment was shown.

  In the all-solid-state battery 100 of FIG. 2, as the starting point of the curved surface part 20c of the outer can 20, the starting point 20c1 outside the curved surface part 20c of the outer can 20 and the starting point 20c2 inside the curved surface part 20c are considered. .

  In the present embodiment, the curved surface portion 20c of the outer can 20 is positioned on the side surface portion side with respect to the overlapping region A. Both the outer start point 20c1 and the inner start point 20c2 of the curved surface portion 20c are side surface portions with respect to the overlapping region A. It is located on the 20b side.

  In the all solid state battery 100 of FIG. 2, the outer start point 20 c 1 among the start points of the curved surface portion 20 c of the outer can 20 is located on the side surface portion 20 b side with respect to the overlapping region A. With this arrangement, when the all-solid-state battery stack 15 is hermetically stored in the outer can 20 and then the stack 15 is constrained, the overlapping region of the negative electrode active material layer 2 and the positive electrode active material layer 4 is obtained. A confining pressure can be uniformly applied to the entirety of A, which is preferable.

  In the all-solid-state battery 100 of FIG. 2, the inner start point 20c2 is located closer to the side surface portion 20b than the outer start point 20c1. By setting it as such an arrangement | positioning, the distance between the side edge part of the duplication area | region A and the side part 20b can be set large. Therefore, even when the overlapping region A undergoes a volume change of at least one of expansion and expansion / contraction during restraint, charge / discharge, etc., a void capable of absorbing the volume change is secured, which is preferable.

  In particular, the bonding between the side surface portion 20b and the upper surface portion in the outer can 20 and the bonding between the all-solid battery laminate 15 and the external terminal are often performed by welding, for example, and have poor strength. Therefore, it is preferable that the position of the end portion on the side surface 20b side of the overlapping region A that may cause a volume change be as far as possible from these welds. The embodiment of FIG. 2 in which the inner start point 20c2 of the outer can 20 is located closer to the side surface portion 20b than the outer start point 20c1 is also preferable from this point of view.

  In the all solid state battery 100 of FIG. 2, the inner start point 20 c 2 is located on the side surface 20 b side with respect to the overlapping region A. Such an arrangement is preferable because the all-solid battery stack 15 can be easily accommodated in the outer can 20 without deforming the non-overlapping region B. Such a positional relationship is also preferable from the viewpoint of preventing the non-overlapping region B from being crushed when a restraining pressure is applied to the all-solid-state battery stack 15 after being stored in the outer can 20.

<Configuration of all-solid battery>
The all-solid-state battery of this embodiment may have a known structure made of known materials, except that the above-described aspect is provided.

[Exterior can]
The outer can in the all solid state battery of the present embodiment includes an outer can body having a bottom surface portion, a side surface portion, and a curved surface portion connecting the bottom surface portion and the side surface portion, and an outer can lid portion serving as an upper surface portion. , And two parts.

  The outer can may be a metal can, for example, aluminum.

[All-solid battery stack]
The all-solid-state battery laminate is a laminate including one or more battery elements in which a negative electrode current collector layer, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector layer are laminated in this order. is there.

  When the all-solid battery stack includes two or more all-solid battery elements, the stacking order of the layers in the adjacent all-solid battery elements may be the same order in the stacking direction, or in the reverse order. May be. Moreover, when the all-solid battery stack includes two or more all-solid battery elements, adjacent all-solid battery elements may be configured to share the positive electrode body layer or the negative electrode body layer.

All-solid battery stack
For example, a negative electrode current collector layer, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, a positive electrode current collector layer, a negative electrode current collector layer, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode The current collector layer may have two or more all solid state battery elements having the same stacking order in the stacking order,
For example, lamination of a negative electrode current collector layer, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector layer In order, the positive electrode current collector layer may be shared, and two or more all solid state battery elements in which the stacking order is reverse may be included.

  The number of all solid state battery elements in the all solid state battery stack is sufficient if it is one or more, and it is not necessarily an integer. For example, the negative electrode current collector layer, the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, the positive electrode current collector layer, the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer are stacked in the order of one The all solid state battery element and the four layers other than the battery element may be laminated while sharing the positive electrode current collector layer.

(Negative electrode current collector layer)
As a material constituting the negative electrode current collector layer, for example, a foil made of SUS, Cu, Ni, Fe, Ti, Co, Zn, or the like can be used.

(Negative electrode active material layer)
The negative electrode active material layer includes at least a negative electrode active material, and for example, a known negative electrode active material such as graphite can be appropriately used.

As the solid electrolyte in the negative electrode active material layer, a sulfide-based solid electrolyte can be preferably used. Specifically, for example, a mixture of Li ₂ S and P ₂ S ₅ (mixing mass ratio Li ₂ S: P ₂ S ₅ = 50: 50 to 100: 0, particularly preferably Li ₂ S: P ₂ S ₅ = 70: 30).

  As the binder in the negative electrode active material layer, for example, a fluorine atom-containing resin typified by polyvinylidene fluoride (PVDF) can be used.

  Examples of the conductive material in the negative electrode active material layer include known conductive materials such as carbon nanofibers (for example, VGCF manufactured by Showa Denko KK) and acetylene black.

(Solid electrolyte layer)
The solid electrolyte layer contains at least a solid electrolyte, and preferably further contains a binder.

  As the solid electrolyte in the solid electrolyte layer, the materials described above as being usable for the negative electrode active material layer can be used.

  Butadiene rubber (BR) is suitable as the binder in the solid electrolyte layer.

(Positive electrode active material layer)
The positive electrode active material layer includes at least a positive electrode active material, and preferably further includes a solid electrolyte, a binder, and a conductive material.

  As said positive electrode active material, well-known positive electrode active materials, such as lithium cobaltate, can be used suitably, for example.

  As the solid electrolyte, the binder, and the conductive material in the positive electrode active material layer, the materials described above as being usable for the negative electrode active material layer can be used as appropriate.

(Positive electrode current collector layer)
As a material constituting the positive electrode current collector layer, for example, a foil made of stainless steel (SUS), Ni, Cr, Au, Pt, Al, Fe, Ti, Zn, or the like can be used.

<All-solid battery manufacturing method>
The all solid state battery of this embodiment may be manufactured by any method. For example,
Producing an all-solid battery laminate including one or more battery elements in which a negative electrode current collector layer, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector layer are laminated in this order;
The all-solid-state battery laminate is placed in the outer can body having the bottom surface, the side surface, and the curved surface portion connecting the bottom surface and the side surface so that the stacking direction is perpendicular to the bottom surface of the outer can. Storing,
It may be manufactured by a method including welding the all-solid battery laminate and an external terminal, and welding an outer can lid portion to the outer can body.

  Each process in the manufacturing method of the all-solid-state battery of this embodiment may be implemented according to a well-known method or after adding an appropriate change by those skilled in the art to this.

DESCRIPTION OF SYMBOLS 1 Negative electrode collector layer 2 Negative electrode active material layer 3 Solid electrolyte layer 4 Positive electrode active material layer 5 Positive electrode collector layer 10 All-solid battery element 15 All-solid battery laminated body 20 Exterior can 20a Bottom part 20b Side part 20c Curved part 20c1 Outside start point of curved surface portion 20c2 Inside start point of curved surface portion 100 All-solid-state battery A Overlapping region B Non-overlapping region

Claims (1)

An all-solid battery in which an all-solid battery stack is hermetically stored in an outer can,
The all-solid battery laminate includes one or more battery elements in which a negative electrode current collector layer, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector layer are laminated in this order,
The outer can has a bottom surface portion, a side surface portion, a curved surface portion connecting the bottom surface portion and the side surface portion, and an upper surface portion facing the bottom surface portion,
The all-solid battery laminate is housed in the outer can so that its stacking direction is perpendicular to the bottom surface of the outer can, and the curved surface portion of the outer can is used to remove the all-solid battery from the entire can. The said all-solid-state battery located in the said side part part rather than the duplication area | region of the negative electrode active material layer and positive electrode active material layer when it observes from the lamination direction of a solid battery laminated body.

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