A battery assembly, comprising: a first printed circuit board having a plurality of first conductive shapes arranged in a matrix-shape; a second PCB oppositely disposed from the first PCB (1020 A) and having a plurality of second conductive shapes arranged in a matrix-shape; a plurality of first springs disposed on the first conductive shapes of the first PCB; a plurality of second springs disposed on the second conductive shapes of the second PCB; a plurality of batteries stacked between the first and second PCBs (1020A, 1020B) in a side-by-side relationship each having a first end in electrical contact with one of the first springs on the first PCB and a second end in electrical contact with one of the second springs on the second PCB; a plurality of fuses integrally formed in the second PCB, each of the fuses electrically connected with one of the second conductive shapes; and a plurality of compensation traces (1150A, 1150B) each connected with one of the fuses and a bus line (1160A, 1160B) where a current flow along, wherein sizes of the compensation traces (1150A, 1150B) vary based on a distance between the second conductive shapes and a connection point (1191, 1193) on the bus line (1160A, 1160B) to compensate for resistance differences from each battery to the connection point (1191, 1193), wherein the compensation traces (1150A, 1150B) located at a first distance from the connection point (1191, 1193) have a higher resistance compared with the compensation traces (1150A, 1150B) located at a second distance from the connection point (1191, 1193) that is longer than the first distance. a first printed circuit board having a plurality of first conductive shapes arranged in a matrix-shape; a second PCB oppositely disposed from the first PCB (1020 A) and having a plurality of second conductive shapes arranged in a matrix-shape; a plurality of first springs disposed on the first conductive shapes of the first PCB; a plurality of second springs disposed on the second conductive shapes of the second PCB; a plurality of batteries stacked between the first and second PCBs (1020A, 1020B) in a side-by-side relationship each having a first end in electrical contact with one of the first springs on the first PCB and a second end in electrical contact with one of the second springs on the second PCB; a plurality of fuses integrally formed in the second PCB, each of the fuses electrically connected with one of the second conductive shapes; and a plurality of compensation traces (1150A, 1150B) each connected with one of the fuses and a bus line (1160A, 1160B) where a current flow along, wherein sizes of the compensation traces (1150A, 1150B) vary based on a distance between the second conductive shapes and a connection point (1191, 1193) on the bus line (1160A, 1160B) to compensate for resistance differences from each battery to the connection point (1191, 1193), wherein the compensation traces (1150A, 1150B) located at a first distance from the connection point (1191, 1193) have a higher resistance compared with the compensation traces (1150A, 1150B) located at a second distance from the connection point (1191, 1193) that is longer than the first distance.