Handheld power tools require battery sizes that sustain high discharge currents and tolerate repeated heavy-duty cycles. Formats like 18650 and 21700 are common in cordless drills, saws, and impact drivers, arranged in robust pack topologies. Battery sizes for handheld tools must combine low internal resistance, thermal stability, and mechanical durability. SUNJ ENERGY supplies cells engineered for high-drain applications with consistent discharge curves and stringent quality control. We partner with tool OEMs to optimize cell selection, pack layout, and safety features—ensuring tools deliver sustained torque, predictable runtime, and long service life across professional and consumer markets.