Electrical double layer capacitor
An electrical double layer capacitor is provided which is capable of ensuring its reliability and providing increased energy density per unit volume of a capacitor. A negative electrode is so configured as to cover all surfaces of a positive electrode and, therefore, there is no portion in which the positive electrode does not face the negative electrode, which enables generation of gas within the capacitor to be suppressed and ensures reliability of the capacitor. Portions in which the negative electrode do not face the positive electrode serve as non-covered portions and, therefore, electrostatic capacitance per unit volume of electrodes is made to increase, and energy density is improved.
1. An electrical double layer capacitor comprising:
a positively polarized electrode in which positive electrode layers are attached, in a covered manner, to surfaces of both sides of a first power collecting body formed in a foil shape or a thin sheet shape;
a negatively polarized electrode in which negative electrode layers are attached, in a covered manner, to surfaces of both sides of a second power collecting body formed in a foil shape or a thin sheet shape; and
a separator;
wherein said positively polarized electrode and a negatively polarized electrode are wound with a separator being interposed between said positively polarized electrode and said negatively polarized electrode;
wherein an electrical double layer is formed at an interface between an electrolytic solution with which said positive electrode layers, said negative electrode layers, said separator are impregnated and, when a voltage is applied, electric charges are accumulated in an electrostatic capacitor of said electrical double layer; and
wherein said negatively polarized electrode is so configured as to cover all surfaces of said positively polarized electrode and portions of said negatively polarized electrode not facing said positive electrode serve as non-covered portions in which said negative electrode layer is not attached in a covered manner.
2. The electrical double layer capacitor according to claim 1 , wherein said positively polarized electrode and said negatively polarized electrode are wound into a cylindrical or elliptical cylinder form with said separator being interposed between said positively polarized electrode and said negatively polarized electrode.
3. The electrical double layer capacitor according to claim 1 , wherein portions of said negatively polarized electrode, not facing said positively polarized electrode in an outermost radius and an innermost radius of the electrical double layer capacitor, serve as said non-covered portions.
4. The electrical double layer capacitor according to claim 2 , wherein said positively polarized electrode and said negatively polarized electrode are wound into a cylindrical or elliptical cylinder form with said separator being interposed between said positively polarized electrode and said negatively polarized electrode.
5. The electrical double layer capacitor according to claim 3 , wherein said portions of said negatively polarized electrode, not facing said positively polarized electrode in an outermost radius and an innermost radius of the electrical double layer capacitor, each are one of said surfaces of said both sides of a second power collecting body.
6. The electrical double layer capacitor according to claim 5 , wherein said positively polarized electrode and said negatively polarized electrode are wound into a cylindrical or elliptical cylinder form with said separator being interposed between said positively polarized electrode and said negatively polarized electrode.