METHOD FOR PREPARING BATTERY PACK

A method for producing an assembled battery, comprising the following steps: (a) producing a plurality of unit cells; (b) arranging the plurality of unit cells in a nested manner such that one unit cell is disposed within another unit cell; and (c) electrically connecting the plurality of unit cells with one another in parallel or in series. The problem that toroidal batteries with high capacity, high power density and small thickness may have a large volume and low energy density is solved by connecting in parallel a plurality of unit cells nested within one another, and heat dissipation of the battery is also further improved. An assembled battery produced by the method is also provided.