Energy + Power + Cycle Life
Ionix’s energy storage technology hybridizes the performance of rechargeable batteries and electrochemical capacitors to create a device that meets the demanding performance requirements of high duty cycle applications, such as start-stop in micro-hybrids, regenerative braking, electrical grid energy storage, and many industrial and consumer electronics applications. The results are high energy devices with greatly enhanced cycle life that are able to operate efficiently at temperatures as low as -40 C. Such performance is not achievable with current battery or capacitor technologies.
By way of example, the following figure plots the energy and power performance of lithium ion batteries and electrochemical capacitors at room temperature. The performance goals1 for a start stop vehicle as defined by the United States Advanced Battery Consortium (USABC) are included in the plot. As can be seen the power and energy requirements of start-stop vehicles can be met by lithium ion batteries at room temperature. Electrochemical capacitors, however, cannot meet the energy requirement but excel in power performance.
At low temperature, however, battery performance degrades markedly while electrochemical capacitor performance remains relatively constant. Power and energy requirements are no longer met by rechargeable batteries. At low temperature power and energy requirements are met with electrochemical capacitors.
Long cycle life is critical for the start stop application. The figure below plots delivered energy as a function of cycle life, comparing the performance of batteries and electrochemical capacitors. Lithium ion batteries degrade rapidly in relation to the performance requirements while electrochemical capacitors are able to meet duty cycle requirements.
Lastly and perhaps most importantly the following figure compares the cost of electrochemical capacitors and lithium ion batteries on a dollar per kilowatt-hour basis. Again the requirements lie between the two technologies with batteries meeting the defined targets while electrochemical capacitor are several orders of magnitude too expensive.
From these data it is clear that the performance requirements for the start stop application lies between the performance of batteries and capacitors. The same is true for many high duty cycle applications. Batteries are energy rich and lower in energy cost ($/kW-hr) than capacitor but lack in low temperature performance and cycle life. Electrochemical capacitors are power rich with long cycle lives but lack in energy and are too costly.
Lithium ion batteries and electrochemical capacitors are two closely related technologies. Both operate using similar design objective and cell materials. Ionix has capitalized on several opportunities to hybridize the devices to create a single device that is able to meet the demanding performance requirements of the start stop and other high duty cycle applications that require high energy, long cycle life and excellent low temperature performance.
- Power and energy requirements defined by USABC (United States Advanced Battery Consortium). See USABC Development of 12 Volt Battery for Start-Stop Application, 2013 World Electric Vehicle Symposium and Exhibition, EVS 2014.