US 5,939,861 A · Control system for on-vehicle battery

Abstract

Charging and discharging of a battery are controlled while observing the state of the battery, thereby improving its efficiency and increasing battery service life. A program control circuit acquires vehicle speed from a vehicle speed sensor and the rotational speed of the internal combustion engine from a rotation sensor. The program control circuit controls an inverter which performs AC-to-DC or DC-to-AC conversion between a motor-generator coupled to the internal combustion engine and a battery mounted on the vehicle. At the same time, the program control circuit acquires the charging and discharging current (i) of the battery, which is detected by a current sensor, and calculates the time integral I of the charging and discharging current (i). The circuit controls the charging current to the battery during regenerative braking, and the discharge current when the vehicle is being driven, in accordance with a function of the time integral I. The overall life of the battery can be lengthened, and the energy lost by the brakes can be most effectively regenerated. Moreover, even if there is variability in the characteristics of the unit cells, its increase can be held in check. In addition, battery costs can be reduced and maintenance simplified.

Claims15

Dependent claims

A control system for a vehicle-mounted battery, said system comprising:

a motor-generator coupled to a drive shaft of a vehicle;
a battery mounted on said vehicle;
an inverter provided between said battery and said motor-generator, said inverter being configured to transmit energy from said battery to said motor-generator and from said motor-generator to said battery;
inverter control means for controlling said inverter;
a battery sensor for detecting a battery current i of said battery;
a program control circuit comprising means for calculating a time integral I=.intg.idt+C of said battery current i, where C is an integration constant corresponding to an initial amount of charging;
and
current control means for controlling said battery current, said battery current comprising a charging current during regenerative braking and comprising a discharging current when said vehicle is being driven, said battery current being controlled in accordance with a function of said time integral I;
said battery comprising plural unit cells, said battery sensor comprising means for individually detecting respective terminal voltages of said unit cells, and said program control circuit comprising means for controlling said charging current during regenerative braking in accordance with said terminal voltages and for controlling said discharge current during driving of said vehicle in accordance with said terminal voltages.

6 more elements

Dependencies are inferred from the claim text.

Control system for on-vehicle battery

Life of this patent

Control system for on-vehicle battery

Life of this patent

Abstract

Claims15