Timothy E. Chin

Lithium Rechargeable Batteries as Electromechanical Actuators

An electromechanical actuation concept utilizing the reversible dilation of ion storage compounds is demonstrated, using prismatic cells based on the LiCOO 2 /graphite couple as the test vehicle. Under zero stress, reversible linear strains of ∼3% were obtained. At 10 MPa stress, 1.5% strain (150 kJ/m 3 mechanical work) was achievable. In tests of maximum actuation speed, cells rated for 20C discharge capability reached ∼1% actuation strain in 80-100 s. This electrochemical actuation approach provides a low-voltage electrically operated mechanism with mechanical energy density exceeding that of high strain polycrystalline piezoelectrics, and may be useful in high strain, high force, moderate bandwidth actuator applications.