Rohm Co., Ltd.

Takahiro Shimizu

Yoichi Tamegai

Shinya Kobayashi

Yoshiki Kobayashi

Isaku Kimura

Multiple voltage monitoring circuits each detect the voltage across at least one corresponding cell from among multiple cells. A current monitoring circuit detects the current that flows through the multiple cells. When the length of a period during which the current that flows through the multiple cells is substantially zero exceeds a predetermined judgment time, the current monitoring circuit asserts a detection signal. Upon detecting an assertion of the detection signal, each voltage monitoring circuit measures the voltage across at least one corresponding cell.

Current monitoring circuit and coulomb counter circuit

The present invention improves the detection accuracy of the state of charge of a battery. A coulomb count value CC is generated by integrating a charge/discharge current Iof a battery (S). An SOC value SOCis calculated (S). Based on an SOC-OCV characteristic predetermined for the battery, an OCV value OCVcorresponding to the value SOCis generated (S). A voltage Vof the battery is detected (S). A voltage drop Vbetween OCVand a detected value Vof the voltage Vis generated (S). A value OCVgreater than the minimum operating voltage of the system by &#x394;V, which corresponds to the voltage drop V, is generated (S). Based on the SOC-OCV characteristic, an SOC value SOCcorresponding to OCVis generated (S). Based on the value SOC, at least one of the values SOC, CC, CC, and SOC-OCV characteristics is corrected.

Remaining capacity detection circuit of rechargeable battery, electronic apparatus using the same, automobile, and detecting method for state of charge

The present invention provides an improved method for detecting the state of charge (SOC) of a battery. A remaining capacity detection circuit detects the SOC of a rechargeable battery. A coulomb counter circuit integrates the charge and discharge currents Iof the battery to generate a coulomb count value CC. A voltage detection circuit detects a voltage Vof the battery. An SOC calculation unit calculates a raw SOC value SOC_cc based on the coulomb count value CC. A discharge correction unit corrects the raw SOC value SOC_cc based on a voltage drop of the battery during the discharging of the battery, and generates a discharge SOC value SOC_dis. A charge correction unit measures a minimum value SOC_dis_min reached by the discharge SOC value SOC_dis during the last discharge of the battery, and calculates a charge SOC value SOC_chg using the minimum value SOC_dis_min during the charging of the battery.

Rechargeable battery remaining capacity detection circuit, electronic machine and vehicle using the same, and state of charge detection method

A method for estimating degradation of a rechargeable battery, includes determining a coulomb count value by integrating a charging/discharging current of the battery, monitoring a state of the battery, detecting that the battery is charged/discharged with a predetermined amount of charges, based on the coulomb count value, and changing an index X indicating degradation of the battery by a variation &#x394;X in accordance with the state of the battery, which is measured in a period during which the battery is charged/discharged with the predetermined amount of charges, if the charging/discharging of the battery with the predetermined amount of charges is detected.

Method for estimating degradation of rechargeable battery, degradation estimation circuit, electronic apparatus and vehicle including same

A battery monitoring unit monitors at least one from among: (i) the attachment state of secondary battery pack; (ii) the low state of a battery voltage VBAT; and (iii) the state of whether it is possible or impossible to use the secondary battery. A battery measurement unit measures the battery voltage VBAT, a charge/discharge current IBAT, and a temperature T of the secondary battery pack, and converts the measured values into digital data. A charging circuit is configured to charge the secondary battery pack using DC voltage from an external power supply based on the state information detected by the battery monitoring unit and the information measured by the battery measurement unit. A coulomb counter measures the charge/discharge current IBAT at predetermined time intervals, and integrates the measurement value, thereby calculating the sum total of the charged/discharged amount. The battery management circuit is monolithically integrated on a single semiconductor substrate.

Growing community of inventors

Kyoto, Japan

Takahiro Shimizu