A battery comprises a substrate comprising an electrolyte between a pair of conductors, at least one conductor having a non-contact surface. A cap is spaced apart from the non-contact surface of the conductor by a gap having a gap distance dg of from about 1 μm to about 120 μm. The gap allows the conductor to expand into the gap. The gap is further bounded by side faces about a surrounding perimeter that may be sealed with a seal. In one version, the ratio of the surface area of the non-contact surfaces on the conductor to the total surface area of the side faces is greater than about 10:1. A pliable dielectric can also be provided in the gap.