Electric Vehicle Charge Control System for Accessory Power Management
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Solution Overview
Problem
Electrically-driven vehicles face the risk of battery damage due to overcharging when external power is supplied for both charging and driving accessory units, leading to reduced convenience as existing solutions restrict accessory functions during charging.
Innovation Solution
A charge control system that dynamically adjusts the charging upper limit based on the status of the accessory unit, setting a lower limit when it is in use, and includes a controller to manage power distribution between the battery and accessory units, ensuring the battery does not exceed a predetermined charge level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electric power from external power supply is supplied to both battery and accessory unit, then charging efficiency is improved, but battery overcharging risk increases
Solution Approach 1:
The charging upper limit is dynamically adjusted based on accessory unit operation status. When accessory units are operating, the charging upper limit is set lower to prevent overcharging, while when accessory units are not operating, the charging upper limit can be higher to improve charging efficiency. This dynamic adjustment resolves the contradiction between charging efficiency and battery safety.
Solution Approach 2:
The system changes the charging upper limit parameter according to the operational state of accessory units. By monitoring whether accessory units are operating and adjusting the charging upper limit accordingly, the system enables efficient charging when safe and prevents overcharging when accessory units are consuming power, thus resolving the contradiction between productivity and reliability.
2Reliability
If accessory unit operation is restricted during external charging, then battery overcharging is prevented, but user convenience deteriorates
Solution Approach 1:
Instead of statically restricting accessory unit operations during charging, the system dynamically adjusts the charging upper limit based on accessory unit status. This allows accessory units to operate freely during charging while the controller monitors and adjusts charging parameters to prevent overcharging, thus maintaining both battery safety and user convenience.
Solution Approach 2:
The system implements feedback control by monitoring accessory unit operation status and adjusting the charging upper limit accordingly. The controller receives feedback about accessory unit power consumption and adjusts charging parameters in real-time to prevent overcharging while allowing accessory units to operate, resolving the contradiction between reliability and ease of operation.
3Speed
If charging upper limit is set high for efficient charging, then charging speed is improved, but overcharging risk increases when accessory units are operating
Solution Approach 1:
The charging upper limit is set dynamically based on accessory unit operation status. When accessory units are not operating, a higher charging upper limit is applied to maximize charging speed. When accessory units are operating, the charging upper limit is reduced to prevent overcharging. This dynamic approach resolves the contradiction between charging speed and overcharging risk.
Solution Approach 2:
The system changes the charging upper limit parameter based on real-time monitoring of accessory unit power consumption. By adjusting this critical parameter according to system conditions, the system achieves high charging speeds when safe and prevents overcharging when accessory units are operating, resolving the contradiction between speed and harmful factors.
Data Source
AI summary
An electrically-driven vehicle 10 comprises a chargeable and dischargeable battery 20, a charger 16 that charges the battery 20 using a supply of electric power from an external power supply 100, an accessory unit 19 that is driven by a supply of electric power from at least one of the battery 20 and the charger 16; and a PM-ECU 18 that controls drive of the charger 16 so that the charged amount of the battery does not exceed a predetermined charging upper limit. The PM-ECU 18 sets the charging upper limit used when the accessory unit 19 is being driven, lower than the charging upper limit used when the accessory unit 19 is not being driven in order to avoid overcharging when excessive electric power is supplied from the accessory unit 19 to the battery 20.