Iowa State University researchers have developed a solution to a problem that has arisen over the last few years with Li-ion batteries difficulties charging in cold temperatures in electric vehicles. Electric vehicles are becoming more and more common, but their batteries do not charge well at temperatures below 0 degrees Celsius.
The current Li-ion batteries that dominate the electric vehicle markets generally do not charge well at temperatures below 0 degrees Celsius. These problems that occur in lower temperatures include shortened battery life, reduced battery capacity, and causing safety hazards. These methods with Lithium-ion batteries are some of the most expensive but least understood components in electric vehicles, which is why solving this issue would reduce operational difficulties. Solving this issue would consist of synthesizing alternating currents to rise the temperature level of the battery cells during subzero weather conditions to the point where fast charging is possible. This process would be completed without running into lithium plating problems.
This control method serves to steer a power electronic circuit to synthesize both direct and alternating currents at the terminals of a battery pack of an electric vehicle using a common power electronic topology. The purpose of synthesizing alternating currents is to rise the temperature level of the battery cells during subzero weather conditions (e.g., -25 degrees Celsius or -13 degrees Fahrenheit) to a temperature point at which fast charging is feasible (e.g., 5 degrees C or 41 degrees F). This without impacting the state of charge of the battery to prevent lithium plating which damages battery cells.
• Newness of the technology
• Performance provided to electric vehicles
• Convenience the technology provides