Vehicle Power Supply Switch Control Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle power source devices with parallel connections of lead and lithium ion batteries face issues with voltage differences causing switch damage due to large currents, especially during charging and discharging, which reduces switch lifespan.
Innovation Solution
A vehicle power supply device with a control circuit that manages the connection between lead and lithium ion batteries via a switch, maintaining the switch in an ON state during normal conditions to minimize voltage differences and prevent excessive current flow, and switching to OFF state when abnormal conditions or voltage differences exceed predetermined values to protect the switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the switch is in the OFF state to protect the lithium ion battery from overcharge or overdischarge, then the lithium ion battery is protected, but a voltage difference occurs between the lead battery and lithium ion battery causing large current flow that can damage the switch
Solution Approach 1:
A control circuit is introduced as an intermediary between the batteries and the switch. The control circuit continuously monitors voltage differences between the lead battery and lithium ion battery, and only permits the switch to be turned ON when the voltage difference is within a safe range, thereby preventing large current flow that could damage the switch while still allowing battery protection functionality
Solution Approach 2:
The control circuit implements a feedback mechanism by continuously detecting the voltage difference between the two batteries and using this information to control the switch state. When the voltage difference exceeds a predetermined threshold, the control circuit keeps the switch OFF; when the voltage difference is within the safe range, the control circuit permits the switch to be ON, thus dynamically adjusting the system based on real-time conditions
2Reliability
If the switch is frequently turned ON and OFF to manage battery charging and discharging, then the lithium ion battery can be protected from overcharge or overdischarge, but the switch lifespan decreases due to wear and tear from large current flows
Solution Approach 1:
The control circuit uses continuous voltage difference feedback to determine the appropriate switch state, minimizing unnecessary switch operations. By only turning the switch ON when voltage conditions are favorable, the system reduces the frequency of switch operations and avoids large current flows that would accelerate wear, thereby extending switch lifespan while maintaining battery protection
Solution Approach 2:
The control circuit acts as an intelligent intermediary that manages switch operations based on real-time voltage conditions. It prevents premature or inappropriate switch operations by monitoring voltage differences, thereby reducing unnecessary wear on the switch while still enabling it to perform its protective function when conditions are appropriate
Data Source
AI summary
A vehicle power supply device comprises a first battery connectable to a starter motor, a vehicle load, and a generator, a second battery different from the first battery in electric characteristics, a connecting switch connected between the first and second batteries, and connecting the first and second batteries in parallel in an ON state of the connecting switch, and a control circuit controlling the connecting switch. In the ON state of the connecting switch, the generator charges the first and second batteries. The control circuit controls to change to the OFF state of the connecting switch in a state of providing electric power to the starter motor, or in a state of detecting an open condition including an abnormal state of the first battery and/or the second battery, and to hold the connecting switch in the ON state in a normal state in which the open condition is not detected.