Compressed Gas in Pico-Cylinders as a Single Use Medical Device Energy Source
When choosing an energy source for a single-use medical device, compressed gas cylinders offer several advantages: high energy and power densities, compact size, light weight, simple integration into a mechanical actuator, and low cost.
While a battery can be a very energy dense storage medium, the power density is actually very low. If a device needs to act energetically over a short period of time (seconds), a large battery or capacitor storage is required. The electrical energy also needs to be converted into mechanical energy in many cases, meaning motors or other actuators as well as electrical circuits for controlling them are needed; increasing the size, weight, complexity and cost of a new device.
Springs offer a very simple and inexpensive energy storage option. The power density is high, meaning the energy can be released very quickly. However, the energy density is very low. If much work needs to be done, the spring can get large. It is also difficult to control the energy release once it is started and some potential energy is converted to kinetic energy by the spring mass, which can pose challenges at the end of the motion.
Compressed gas cylinders offer several advantages over batteries, motors, and springs. The energy density is higher than springs and the power density is higher than batteries. No additional devices are required to convert the energy into mechanical work, simplifying device designs.