The present invention discloses a device and method pertaining to battery construction. In the preferred embodiment, the shape and construction of the battery is designed to maximize energy density and efficiency, while minimizing volume and related restrictions. Furthermore, the efficient, simplified internal construction of the present invention, using readily available tubes, pins and spacers, renders it safe and reliable for medical applications, and lends to relative ease and cost effectiveness in manufacturing. The utilization of a neutral case further adds to the safety and reliability of the present invention. Also, the strategic positioning of the electrolyte fill hole allows for quick filling. A related battery construction tool and method are also disclosed adding to the overall usefulness and efficiency of the present invention.