Solid state battery
A solid state battery that includes: a battery element including, along a stacking direction, one or more battery constituent units including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer; first and second external terminals joined to an extended portion of each electrode layer of the positive electrode layer and the negative electrode layer, respectively; and a protective layer that covers a surface of the battery element other than the extended portions of each electrode layer, the protective layer including a side portion on a central region of a side portion of the battery element extending in substantially the same direction as the stacking direction and in which a first thickness dimension of a first portion is larger than a second thickness dimension of a second portion other than the first portion.
1. A solid state battery comprising:
a battery element including, along a stacking direction, one or more battery constituent units including a positive electrode layer having a positive electrode extended portion, a negative electrode layer having a negative electrode extended portion, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer;
a first external terminal joined to the positive electrode extended portion of the positive electrode layer;
a second external terminal joined to the negative electrode extended portion of the negative electrode layer; and
a protective layer that covers a surface of the battery element other than the positive electrode extended portion of the positive electrode layer and the negative electrode extended portion of the, the protective layer including a side portion which is located on a central region of a side portion of the battery element extending in substantially a same direction as the stacking direction, a first portion of the side portion of the protective layer having a first thickness dimension that is larger than a second thickness dimension of a second portion of the side portion of the protective layer other than the first portion, and
a third thickness dimension of at least one of mutually opposing upper side portion and lower side portion of the protective layer on a main surface of the battery element extending in a direction substantially perpendicular to the stacking direction is larger than the first thickness dimension of the side portion of the protective layer.
2. The solid state battery according to claim 1 , wherein in a sectional view, the first thickness dimension is a maximum thickness dimension of the side portion of the protective layer.
3. The solid state battery according to claim 1 , wherein the first thickness dimension is 20 μm to 200 μm.
4. The solid state battery according to claim 3 , wherein the second thickness dimension is 5 μm to 50 μm.
5. The solid state battery according to claim 1 , wherein the side portion of the protective layer is curved outward in a sectional view.
6. The solid state battery according to claim 1 , wherein a corner portion of the protective layer is curved in a sectional view.
7. The solid state battery according to claim 1 , wherein the third thickness dimension is 200 μm to 1000 μm.
8. The solid state battery according to claim 7 , wherein the first thickness dimension is 20 μm to 200 μm.
9. The solid state battery according to claim 1 , wherein the protective layer includes a resin-free insulating material.
10. The solid state battery according to claim 9 , wherein the resin-free insulating material contains glass and ceramics.
11. The solid state battery according to claim 1 , wherein the protective layer is a water vapor transmission preventing layer.
12. The solid state battery according to claim 1 , wherein the protective layer is a sintered body containing insulating substance particles.
13. The solid state battery according to claim 12 , wherein the sintered body has a porosity of 0.1 vol % to 20 vol %.