Vehicle Battery Relay Control for Low-SOC Door Power and Charging
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Solution Overview
Problem
Lithium iron phosphate batteries in vehicles are discharged when power is temporarily supplied to electric loads during door operations, even when the vehicle is not turned on, due to uncontrolled relay states and inability to charge externally, leading to potential battery damage and the need for replacement.
Innovation Solution
An apparatus and method that control a relay to block power to electric loads when the battery state of charge is low, and temporarily supply power for door operations, while allowing external charging to prevent discharge and overcharging, using a controller that monitors SOC and external device connections to manage relay states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the relay is opened to block power from the battery to protect the battery, then the battery is protected from discharge, but the relay cannot be controlled and the battery cannot be charged by external devices
Solution Approach 1:
The patent introduces a control circuit that acts as an intermediary between the relay control terminal and the relay coil. This control circuit includes a second switch that can be controlled by the controller to temporarily close the relay when external charging is needed, even while the main protection relay remains open. This intermediary mechanism resolves the contradiction by enabling selective relay closure for charging purposes without compromising overall battery protection.
2Ease of operation
If power is temporarily supplied to electric loads during door operations, then door operations are enabled, but the battery is fully discharged when the vehicle is not turned on
Solution Approach 1:
The patent implements partial action by providing temporary power supply only for essential door operations rather than continuous power to all electric loads. The controller detects door opening/closing events and supplies power only during these specific operations, then immediately blocks power again. This partial power supply approach enables necessary door functionality while minimizing battery discharge, resolving the contradiction between operational ease and energy conservation.
3Power
If the relay is controlled to close to supply power from the battery, then electric loads receive power, but the battery cannot be protected from discharge when SOC is low
Solution Approach 1:
The patent implements dynamic control of the relay based on real-time SOC detection. The controller continuously monitors battery SOC levels and dynamically adjusts relay state: when SOC is above the threshold, the relay remains closed to supply power to electric loads; when SOC drops below the threshold, the controller opens the relay to block power and protect the battery. This dynamic adaptation resolves the contradiction by making power supply conditional on battery state, ensuring both load operation and battery protection at different times.
Data Source
AI summary
An apparatus for controlling a vehicle includes a relay which is controlled to close to supply a power from a battery to an electric field load or is controlled to open to block the power, a sensor that detects a state of charge (SOC) value of the battery and opening and closing of a door of the vehicle, and a controller that is configured to control the relay to close based on the power supplied from the battery or a power of an external power device, when the controller concludes that the SOC value of the battery is less than a first reference value and that the door is opened, and charges the battery with the power supplied from the external electronic device.