Sanyo Electric Co., Ltd.

Toru Nishikawa

Atsushi Kawasumi

Shinichi Matsuura

Hitoshi Hamaguchi

Kenichi Kobayashi

Toru Morioka

Shinichi Itagaki

Takao Kobayashi

After the highest voltage of a rechargeable battery becomes higher than 4.0 V, when the charging current keeps lower than 50 mA for 20 seconds, a first point is detected for stopping charging the battery. Also, after the highest voltage becomes higher than 4.0 V, the charged capacity value and the discharged capacity value are added and subtracted for integrating the charged/discharged capacity if the highest voltage keeps higher than the integration start voltage. When the integration result shows that the battery is charged totally after the highest voltage becomes higher than 4.0 V, and when the absolute value of the integration result becomes larger than 50% of the designed capacity of the battery, the point second is detected for stopping charging the battery.

Charge stop point detecting method, charge stop point detecting device, and a battery pack

One cycle is corrected every charging/discharging cycle in accordance with a cycle deterioration accelerating coefficient. The corrected one cycles are accumulated. A storage period is corrected in accordance with a storage deterioration accelerating coefficient every hour. The corrected storage periods are accumulated. In the storage period, a rechargeable battery is stored with the terminal voltage higher than a predetermined voltage. A deterioration coefficient is obtained as the product of a cycle deterioration coefficient calculated in accordance with the accumulated cycle number, and a storage deterioration coefficient calculated in accordance with the accumulated value of the storage periods (Step S). If the deterioration coefficients falls within the range 0.3 to 0.7 (Step S: NO), the setting voltage in constant-voltage and constant-current charging operation is decreased from 4.2 to 4.1 V (S). If it is smaller than 0.3 (S: NO, S: YES), the setting voltage is decreased to 3.8 V (S).

Rechargeable battery charging method and battery pack capable of suppressing deterioration degree

The battery pack is provided with an analog front-end that detects battery voltage, and a micro-controller connected to the analog front-end that accepts analog voltage signals from the analog front-end as input. The micro-controller switches voltage signals input from the analog front-end to determine failure of the analog front-end or the micro-controller.

Battery pack

A battery pack updating method updates firmware stored in internal control circuit memory via an update signal sent from a main device that supplies power. When battery pack memory is updated, an AC adapter is connected to the main device, and power is supplied to the main device from the AC adapter. The updating method transmits a charging and discharging blocking signal from the main device to the battery pack control circuit via a communication line. The charging and discharging blocking signal stops discharge from the battery pack rechargeable battery, and stops charging of the rechargeable battery. With rechargeable battery discharging and charging to and from the main device stopped by the charging and discharging blocking signal, the updating method transmits update data from the main device to the battery pack control circuit to update memory.

Battery pack updating method

The rechargeable battery abnormality detection apparatus is provided with an internal short circuit detection section () that monitors rechargeable battery () voltage change when no charging or discharging takes place, and detects internal short circuit abnormality when battery voltage drop during a predetermined time period exceeds a preset threshold voltage; a degradation appraisal section () that judges the degree of rechargeable battery degradation; and a threshold control section () that incrementally increases the threshold voltage according to the degree of degradation determined by the degradation appraisal section ().

Rechargeable battery abnormality detection apparatus and rechargeable battery apparatus

A method controls a battery pack that includes a rechargeable battery, a control circuit that controls charge operation of the battery, and a charge control element that controls the charge current through the control circuit. In the method, even though the control circuit controls the charge control element so that the charge control element turns to OFF, in a case where the charge current is detected, the control circuit determines that abnormality occurs if detecting that the current flows at a rate not less than a first current value during a first detection period, and additionally determines that abnormality occurs if detecting a state the current flows at a rate less than the first current value for a second detection period longer than the first detection period.

Method for controlling battery pack

A battery pack includes a switching element, a heat resistor, and a fuse. The switching element turns to ON if the battery pack becomes in an abnormal state. The heat resistor is connected to the switching element and a battery in series. Current flows through the heat resistor when the switching element turns to ON. The fuse is located in a position where the fuse is heated by the heat resistor through which the current flows. The fuse is connected to the battery in series so that the fuse is disconnected with heat by the heat resistor at high temperature. Thus, the fuse cuts off a current flow in the battery. If the battery pack is in an abnormal state, when the capacity or voltage of the battery is less than a preset capacity or voltage value, the fuse is disconnected with heat by turning the switching element to ON.

A battery pack provided with a current cut-off device connected in series with batteries, a tamper detector to detect tampering and issue a tamper signal, and a control circuit connected to the tamper detector. If the tamper detector detects tampering with the battery pack, the control circuit switches the current cut-off device off to shut off current to the batteries, or it issues a tamper signal.

Growing community of inventors

Sumoto, Japan

Toru Nishikawa