Patent 9246147 was granted and assigned to Panasonic on January, 2016 by the United States Patent and Trademark Office.
A battery retainment block includes a plurality of block pieces each having a battery storage unit for retaining a battery. The plurality of block pieces are aligned and, among the plurality of block pieces, two block pieces that are adjacent to each other are coupled together. A gap is provided between the two block pieces that are adjacent to each other to serve as a circulation space for circulating a medium.