 Lithium-thionyl chloride batteries are non-rechargeable, but they offer high and reliable performance and a long lifetime that makes them particularly well suited for IoT applications. But how do they work? A battery is a system which stores chemical energy and converts it into electrical energy thanks to an electrochemical reaction. When the battery is connected to an external circuit, such as a communicating device, an oxidation-reduction reaction is triggered, releasing energy in the form of an electrical current. A lithium-sion chloride battery is made up of a negative material called the anode, the electron provider, which is made of lithium metal connected to the negative pole of the battery, a porous carbon mass where the reduction reaction occurs, a separator to isolate the negative from the positive materials, a positive material called the cathode, the electron taker, the thionyl chloride contained in the electrolyte which is also conducting ions from the anode to the carbon mass, and a current collector connected to the positive pole of the battery. All of these elements are enclosed in a hard, hermetically sealed cylindrical casing. The lithium-sion chloride systems are specific batteries as the thionyl chloride is also the solvent of the electrolyte, therefore it is called a liquid cathode system. One of the many advantages of these batteries is their high operating voltage reaching 3.6 volts due to the nature of electrochemical couple. The stronger the oxidation or reduction power in a given battery chemistry, the greater the resulting nominal voltage of this battery. For example, alkaline systems' nominal voltage reach 1.5 volts while lithium-sion chloride systems features 3.6 volts. Moreover, its voltage remains very stable during the discharge, which is unique and makes these batteries particularly suited for electronics applications. When you connect a device, it creates a conductive path and electrons start flowing outside the device. Positive ions generated at lithium anode are transported to the carbon mass by diffusion within the liquid ionically conducting electrolyte. On their way, they cross the porous separator. This electrochemical process, taking place inside the cell, progressively consumes active anodic and cathodic materials over the whole discharge time and eventually it stops providing electrons to the external circuit. That's how the battery dies. This can be quick or long depending on how much energy is required by the device. Two other phenomena can impact the life duration of a battery, the self-discharge and in the case of a liquid cathode system, the passivation. Saft, we energize the world on land, at sea, in the air and in space.