Sanyo Electric Co., Ltd.

Panasonic Corporation

Hisashi Kameyama

Takuya Hirota

Masato Nakayama

Takahiro Yamashita

Toshiyuki Nakatsuji

Naoki Kawai

Hisanori Amasaki

Yusuke Omote

Naoto Matsuda

Jeewook Chang

Tetsuya Kawasaki

Motoji Takeuchi

Mitsuhiro Hamada

A protection circuit for a battery includes a discharge FET, a control circuit, a first small-signal FET, and a second small-signal FET. The discharge FET connected in series to a battery interrupts an electric current. The control circuit switches on or off the discharge FET. The first small-signal FET connected in parallel between a gate (G) and a source (S) of the discharge FET is switched to an ON state, to set a gate voltage of the discharge FET to an OFF-state voltage. The second small-signal FET connected in parallel between G and S of the discharge FET detects a voltage between a drain (D) and S of the discharge FET. When the voltage between D and S of the discharge FET exceeds a preset voltage, the second small-signal FET is switched to an ON state to set the gate voltage of the discharge FET to the OFF-state voltage.

Protection circuit for battery and power supply device provided with said protection circuit

A power supply device includes a spike absorption circuit that suppresses an avalanche breakage of a current shutdown switch due to a kickback voltage that may appear in response to the cut-off of a load current. The current shutdown switch is connected to secondary batteries. The spike absorption circuit is a series circuit of a protection switch, formed of a semiconductor element, and a diode. The power supply device further includes: a small-signal switch that controls turn-on and turn-off of the protection switch; and a delay circuit that maintains the small-signal switch in an ON state over a setup time after a current shutdown timing of the current shutdown switch. The delay circuit maintains the small-signal switch in the ON state over the setup time (T), and the small-signal switch thereby causes the protection switch to the ON state. Then, the spike absorption circuit damps the kickback voltage.

Power supply device

The battery pack including a battery group in which a plurality of secondary batteries are connected in series; a detector that detects a charging and discharging current value flowing in the battery group and a voltage value of the battery group in a time-division manner by switching between the current value and the voltage value using an electronic circuit; and a controller/operator that performs operation and control using the current value and the voltage value detected by the detector. In the battery pack, the detector detects current values before and after the voltage value of the battery group is detected, and the controller/operator determines that the voltage value of the battery group is influenced by the peak discharge power when at least one of the current values exceeds a predetermined threshold.

Battery pack and method for controlling discharge of secondary cell

A full charge capacity value correction circuit includes: a current detection portion which detects a current value in a secondary battery; a voltage detection portion which detects a terminal voltage value of the secondary battery; a capacity storage portion which stores a full charge capacity value of the secondary battery; a remaining quantity calculation portion which calculates a remaining charging quantity in the secondary battery a remaining quantity estimation portion which estimates a remaining quantity of the secondary battery and a full charge capacity value correction portion which, when an estimated remaining quantity becomes equal to a reference value set in advance, adds a difference electrical quantity, to the full charge capacity value stored in the capacity storage portion, or subtracts the difference electrical quantity from the full charge capacity value stored in the capacity storage portion based on an estimated remaining quantity and an accumulated remaining quantity.

Full charge capacity value correction circuit, battery pack, and charging system

Growing community of inventors

Osaka, Japan

Hisashi Kameyama