Abstract: A safe state detection method for a lithium-ion secondary battery, includes: calculating an absolute value of a differential coefficient of a discharge curve from which a voltage equivalent to a voltage drop of the lithium-ion secondary battery is removed; determining a first battery voltage when the degree of increase in the absolute value of the differential coefficient is greater than a threshold value; determining a second battery voltage at a start of an increase in oxidation heat in response to the first battery voltage, the oxidation heat being heat generated inside the lithium-ion secondary battery when the lithium-ion secondary battery is overcharged; and detecting a safe state of the lithium-ion secondary battery, based on the determined second battery voltage.

Abstract: Provided is an electric energy storage device capable of improving a charging efficiency when electric power supplied with an input current having a current value repeatedly exhibiting peaks and valleys is to be storaged by using a secondary battery and an electric double-layer capacitor. The electric energy storage device includes: an electric double-layer capacitor; and a battery unit including at least one secondary battery, the battery unit being connected in parallel to the electric double-layer capacitor, in which: a ratio of an internal resistance of the electric double-layer capacitor to an internal resistance of the battery unit is determined according to parameters relating to the input current.

Abstract: Provided is an electric energy storage device capable of improving a charging efficiency when electric power supplied with an input current having a current value repeatedly exhibiting peaks and valleys is to be storaged by using a secondary battery and an electric double-layer capacitor. The electric energy storage device includes: an electric double-layer capacitor; and a battery unit including at least one secondary battery, the battery unit being connected in parallel to the electric double-layer capacitor, in which: a ratio of an internal resistance of the electric double-layer capacitor to an internal resistance of the battery unit is determined according to parameters relating to the input current.

Abstract: A case (2) houses positive electrodes and negative electrodes of an electrical double layer capacitor. An insulator (10) is so arranged as to cross four surfaces around the case (2). Positive electrode side terminals (21) are welded on respective positive electrodes (20) of a capacitor main body (11). The positive side terminals (21) are bundled together, and are electrically connected to a connection portion (22) which is formed on an inner wall surface of a divided surface (3A) of a first side surface (3) constituting the case (2). Negative electrode side terminals (31) are welded on respective negative electrodes (30) of the capacitor main body (11). The negative electrode side terminals (31) are bundled together, and are electrically connected to a connection portion (32) which is formed on an inner wall surface of a divided surface (3B) of the first side surface (3) constituting the case (2).

Abstract: Electrical storage devices having excellent low-temperature properties can be obtained by using a quaternary salt (or ionic liquid) of general formula (1) below as an electrolyte salt for electrical storage devices or a liquid electrolyte for electrical storage devices. In formula (1), R1 to R4 are each independently an alkyl group of 1 to 5 carbons or an alkoxyalkyl group of the formula R?—O—(CH2)n—, with the proviso that at least one group from among R1 to R4 is the above alkoxyalkyl group. X is a nitrogen or phosphorus atom, and Y is a monovalent anion.

Abstract: An electric double layer capacitor is configured as follows. A changeover switch is connected to a positive electrode of the electric double layer capacitor, a power supply or electric load is connected to a terminal a of the changeover switch, and an auxiliary electrode is connected to a terminal b thereof through a resistor. The changeover switch is being switched to the terminal a, and discharge and charge of the electric double layer capacitor are repeated. When a discharge capacity becomes equal to or less than a lower limit threshold or an internal resistance becomes equal to or more than an upper limit threshold, the changeover switch is switched to the terminal b from the terminal a to make a channel between the positive electrode and the auxiliary electrode be a closed circuit through the resistor, and resistance discharge is conducted from the positive electrode.

Abstract: A positive side terminal electrode and a negative side terminal electrode which are exposed to the exterior of a resin enclosure pass through a positive side opening and a negative side opening formed on the enclosure, respectively, and are connected to a positive side electrode and a negative side electrode, respectively, of an electric double-layer capacitor put away in the interior of the enclosure. The positive side terminal electrode is thermally welded to inner surfaces of the positive side opening over the entire periphery thereof, and the negative side terminal electrode is thermally welded to inner surfaces of the negative side opening over the entire periphery thereof.

Abstract: Electrical storage devices having excellent low-temperature properties can be obtained by using a quaternary salt (or ionic liquid) of general formula (1) below as an electrolyte salt for electrical storage devices or a liquid electrolyte for electrical storage devices. In formula (1), R1 to R4 are each independently an alkyl group of 1 to 5 carbons or an alkoxyalkyl group of the formula R?—O—(CH2)n—, with the proviso that at least one group from among R1 to R4 is the above alkoxyalkyl group. X is a nitrogen or phosphorus atom, and Y is a monovalent anion.

Abstract: A positive side terminal electrode and a negative side terminal electrode which are exposed to the exterior of a resin enclosure pass through a positive side opening and a negative side opening formed on the enclosure, respectively, and are connected to a positive side electrode and a negative side electrode, respectively, of an electric double-layer capacitor put away in the interior of the enclosure. The positive side terminal electrode is thermally welded to inner surfaces of the positive side opening over the entire periphery thereof, and the negative side terminal electrode is thermally welded to inner surfaces of the negative side opening over the entire periphery thereof.

Abstract: Electrical storage devices having excellent low-temperature properties can be obtained by using a quaternary salt (or ionic liquid) of general formula (1) below as an electrolyte salt for electrical storage devices or a liquid electrolyte for electrical storage devices. In formula (1), R1 to R4 are each independently an alkyl group of 1 to 5 carbons or an alkoxyalkyl group of the formula R?—O—(CH2)n—, with the proviso that at least one group from among R1 to R4 is the above alkoxyalkyl group. X is a nitrogen or phosphorus atom, and Y is a monovalent anion.

Abstract: The water present within an ionic liquid that is in a liquid state at 25° C. or an organic solution containing at least one ionic compound is decomposed by bringing electrodes into contact with the ionic liquid or organic solution within an atmosphere having a dew-point temperature not higher than ?40° C. or under a reduced pressure of not more than 75 torr, thereby reducing the water content. This process makes it possible to obtain highly dehydrated ionic liquids.

Abstract: An electric double layer capacitor is configured as follows. A changeover switch is connected to a positive electrode of the electric double layer capacitor, a power supply or electric load is connected to a terminal a of the changeover switch, and an auxiliary electrode is connected to a terminal b thereof through a resistor. The changeover switch is being switched to the terminal a, and discharge and charge of the electric double layer capacitor are repeated. When a discharge capacity becomes equal to or less than a lower limit threshold or an internal resistance becomes equal to or more than an upper limit threshold, the changeover switch is switched to the terminal b from the terminal a to make a channel between the positive electrode and the auxiliary electrode be a closed circuit through the resistor, and resistance discharge is conducted from the positive electrode.

Abstract: An electric double-layer capacitor has an electrolyte solution and an element constructed of a positive electrode and a negative electrode which are each composed of a current collecting substrate and an active material composition, and a separator situated between the positive and negative electrodes. When the element is in place within the capacitor, the portion of the separator sandwiched between the active material compositions of the respective electrodes has a pore volume which is at least 0.4 times the total pore volume of the positive and negative electrodes. This construction enables the separator to hold the electrolyte solution required by the electrodes for charging and discharging, thus endowing the capacitor with a high capacitance and a long cycle life.

Abstract: A charging system for a rechargeable battery with a rapid charge capacity. This invention relates to the charging system for the rechargeable battery with a rapid charge capacity which can be recharged at a public place. The charging system comprises a charging equipment for the rapid charge battery, a measurement display unit which measures and displays a charging condition and deterioration of the rapid charge battery, and a fee collection device which collects a charging fee.

Abstract: An electric double-layer capacitor consists in part of an electrolyte solution and an element constructed of a positive electrode and a negative electrode which are each composed of a current collecting substrate and an active material composition, and a separator situated between the positive and negative electrodes. When the element is in place within the capacitor, the portion of the separator sandwiched between the active material compositions of the respective electrodes has a pore volume which is at least 0.4 times the total pore volume of the positive and negative electrodes. This construction enables the separator to hold the electrolyte solution required by the electrodes for charging and discharging, thus endowing the capacitor with a high capacitance and a long cycle life.

Abstract: A nonaqueous electrolyte secondary battery is made up of a positive electrode and a negative electrode which are composed of a lithium ion-occluding and releasing material and a binder polymer, at least one separator for separating the positive and negative electrodes, and a nonaqueous electrolyte which is composed of a lithium salt and an organic solvent. The electrolyte includes also a substance which is oxidized at the positive electrode at a cell voltage of from 4.1 V to 5.2 V, and which provokes an oxidation reaction that differs from the lithium-releasing reaction. The presence of this substance improves the overcharge characteristics and safety of the nonaqueous electrolyte secondary battery.

Abstract: A capacitor unit with plural double layer capacitors eliminating irregularity in a state of charge of the respective double layer capacitor in the capacitor unit. A capacitor unit, a capacitor unit control method, a capacitor unit control apparatus and a vehicle charging system, wherein a chargeable and dischargeable capacitor unit 1 with plural electronic double layer capacitors 11 connected in series is characterized in that electric double layer capacitors 11 in a higher state of charge is subject to discharge so that a state of charging of the respective electric double layer capacitor 11 may become approximately equal to each other.

Abstract: The water present within an ionic liquid that is in a liquid state at 25° C. or an organic solution containing at least one ionic compound is decomposed by bringing electrodes into contact with the ionic liquid or organic solution within an atmosphere having a dew-point temperature not higher than −40° C. or under a reduced pressure of not more than 75 torr, thereby reducing the water content. This process makes it possible to obtain highly dehydrated ionic liquids.

Abstract: Electrical storage devices having excellent low-temperature properties can be obtained by using a quaternary salt (or ionic liquid) of general formula (1) below as an electrolyte salt for electrical storage devices or a liquid electrolyte for electrical storage devices.

Abstract: A capacitor system suitable for charging and discharging of a vehicle such as discharging due to starting of an engine, charging by an alternator, and recharging upon braking. The capacitor system can be a vehicle power source having several connected cells in which ion conductive materials are arranged between a pair of electrode structures with large surface area materials and an electric double layer is formed between the large surface area materials in the electrode structure and an electrolyte of the ion conductive materials. Charging and discharging are controlled for state of charge of the capacitor unit with several connected modules to be within a predetermined range. A minimum charge within the predetermined range is sufficient for the engine to start while a maximum charge within the predetermined range is within a rated voltage of the capacitor unit with several connected modules.