Lithium Ion Capacitor

Abstract

A lithium ion capacitor has an electrolytic solution that contains: 100 parts by volume of a solvent containing 20 to 50 parts by volume of propylene carbonate, 10 to 35 parts by volume of dimethyl carbonate, and 15 to 70 parts by volume of ethyl methyl carbonate; and lithium bis(fluorosulfonyl)imide, as an electrolyte. The lithium ion capacitor can maintain its initial high capacitance and low internal resistance, while also undergoing minimal characteristics changes in a low-temperature environment, even after exposure to a high-temperature, high-voltage environment.

Description

technical field [0001] The present invention relates to lithium ion capacitors. Background technique [0002] An electric double layer capacitor using a non-aqueous electrolytic solution can increase a withstand voltage and store a large amount of energy because the electrolysis voltage of the solvent is high. In particular, lithium-ion capacitors have a larger capacitance per unit volume than electric double-layer capacitors, and can have a longer life than lithium-ion secondary batteries by reducing the discharge depth of the negative electrode and using a polarizable positive electrode material. In recent years, lithium ion capacitors have been required to reduce internal resistance at low temperatures and ensure reliability at high temperatures. Regarding the low-temperature characteristics, it is considered that the dissociation of the electrolyte in the electrolyte solution becomes difficult to occur or the viscosity of the electrolyte solution increases, and the inte...

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Problems solved by technology

Regarding the low-temperature characteristics, it is considered that the dissociation of the electrolyte in the electrolyte solution becomes difficult to occur or the viscosity of the electrolyte solution increases, and the internal resistance increases. Regarding the high-temperature reliability, it is considered that the PF as the electrolyte 6 － Decomposition products such as hydrogen fluoride and other anions are decomposed, so various characteristics of the monomer are deteriorated

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