Li-ion Battery New ultra-safe Li-ion electric vehicle battery can last for 1 million miles
A research team in Pennsylvania State University's Battery and Energy Storage Technology (BEST) Center has developed a safe, high power lithium-ion battery that can last for one million miles.
Electric vehicle batteries typically require a tradeoff between safety and energy density. Up until now, batteries with high energy and power density (which is required for uphill driving or merging on the freeway) weren't 100 percent safe. These types of batteries have caught fire or exploded on more than one occasion in recent years, causing many people to question whether electric vehicles are truly safe to drive.
Despite batteries with low energy/power density being generally safer, many battery engineers have opted for the high energy/power density alternatives due to their stronger performance.
No more tradeoff between safety and energy density
Thanks to new research by a team at Pennsylvania State University's Battery and Energy Storage Technology (BEST) Center, battery engineers might not have to decide between safety and capacity much longer.
Chao-Yang Wang, Professor of Mechanical, Chemical and Materials Science and Engineering, developed a self-heating battery to overcome the problem of poor performance in cold climates about four years ago. The battery uses an electric current to heat up in seconds compared to the hours an external heater required. By heating the battery from room temperature to around 60 degrees Celsius (140 degrees F) the battery gets an instant boost in reactivity because the law of kinetics is that reactivity increases exponentially with temperature.
The self-heating battery, called the All Climate battery, has been adopted by several car companies, including BMW, and was chosen to power a fleet of 10,000 vehicles that will be used to ferry people between venues at the next Winter Olympics in Beijing.
Next step: develop a solid-state battery
The BEST Center tests the safety of the battery using nail penetration equipment. They drive the nail into the cell, causing short-circuiting. They then monitor the cell for temperature and voltage. The difference in temperature for the passivated cell was 100 degrees C compared to a standard battery cell, which was 1,000 degrees C, an enormous improvement.
Because their batteries are built using stable materials, they have a long cycle life. Even at 60 degrees C, their cycle number is over 4,000, which translates to over a million miles.
The team's next project will be to develop a solid-state battery, which will likely require heating as well.