Power supply device for vehicle

Abstract

The invention aims to detect the disconnection of a ground line in the loae driven state of a vehicle by using a simple circuit. A power supply device for a vehicle includes negative-side and positive-side battery blocks serially connected to each other through a resistor element 19. The ends of the element 19 correspond to reference and auxiliary ground points 8A and 8B. A voltage detector 3 detects the voltages of battery modules 2 of a load-driving battery 1. The detector 3 includes an asymmetric resistor circuit that is asymmetrically constructed with respect to the reference point 8A. The detector 3 detects the voltage of the auxiliary point 8B with respect to the reference point 8A in a load driven state. A disconnection detecting circuit 20 compares the detected voltage with a reference voltage of the auxiliary point 8B with respect to the reference point 8A not in the load driven state, and determines that the line 9 is disconnected in the load driven state if the deviation of the detected voltage from the reference voltage falls out of a predetermined range.

Description

technical field [0001] The present invention relates to a power supply device for driving an electric motor for driving an electric vehicle such as a hybrid car or an electric vehicle, and more particularly to a power supply device for a vehicle including a voltage detection circuit for detecting voltages of battery modules connected in series . Background technique [0002] In order to increase the output of a power supply device that drives an electric vehicle, it is necessary to increase the voltage of the battery. This is because the output is proportional to the product of the battery's voltage and current. For example, the battery of a power supply device for running a hybrid car or an electric car has an extremely high range of 200V or more. In a high-voltage battery, a plurality of secondary batteries are connected in series to form a battery module, and the battery modules are further connected in series to increase an output voltage. [0003] As described above,...

AI Technical Summary

Problems solved by technology

However, since the existing power supply device for a vehicle cannot detect the disconnection of the ground wire 79 in the running state, if the ground wire 79 is disconnected in the running state, it will not be possible to correctly detect the battery module constituting the running battery 71. Disadvantages of 72 voltage

The driving battery 71 uses the voltage of the battery module 72 to detect overcharge or overdischarge, thereby controlling charging and discharging. Therefore, if the voltage of the battery module 72 cannot be accurately detected, the overcharging or overdischarging of the driving battery 71 cannot be reliably protected. discharge, resulting in the disadvantage that the driving battery 71 cannot be charged and discharged under normal conditions

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