APPLICATIONS OF TECHNOLOGY:
Safe, cost-effective, solid-state rechargeable batteries for
- Laptops and computer peripherals
- Digital cameras and camcorders
- Cell phones
- Portable media players (MP3, DVD)
- Other portable devices, such as hearing aids
- Automatic shutoff mechanism prevents lithium from melting and avoids explosive chemical reactions
- No additional materials or steps required to prevent overheating
- Reduced dendrite growth
Rechargeable lithium batteries are superior to other rechargeable batteries due to their ability to store more energy per unit size and weight and to operate at higher voltages. The performance of lithium ion batteries available today, however, has been compromised by their tendency to overheat during operation. This condition, called “thermal runaway,” can melt the battery’s lithium metal and, in the most serious cases, result in explosive chemical reactions.
To overcome this problem, Nitash Balsara, Ashoutosh Panday, and Scott Mullin of Berkeley Lab created the first viable self-regulating, dry phase (or solid state), polymer electrolyte battery system to prevent thermal runaway in rechargeable lithium battery cells. The “built-in” safety device requires no additional materials, steps, or manufacturing costs beyond those currently in use to produce lithium ion batteries.
A unique new technology slows down the electrochemical reactions that occur during battery operation, which, in turn, lowers the operating temperature of the battery and prevents thermal runaway. The system contains a lithium salt dissolved within the conductive linear block of its block copolymer and precipitates lithium salt at 120° Celsius—the temperature at which a compound such as sodium chloride, or salt, typically dissolves. The inventors demonstrated that the precipitated salt lowers the electrolyte’s conductivity by a factor of between five and 10 when temperatures reach or exceed 110° Celsius.
DEVELOPMENT STAGE: Proven principle
STATUS: Issued U. S. Patent 8,703,310. Available for licensing or collaborative research.
SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:
REFERENCE NUMBER: IB-2628