Auxiliary Battery Charging Control for Eco-Friendly Vehicles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing supplementary charging methods for auxiliary batteries in eco-friendly vehicles fail to secure a sufficient charge current due to battery aging, leading to inadequate charging even when the battery is charged to a reference state of charge.
Innovation Solution
A supplementary charging system that selects between constant voltage and constant current charging methods based on the auxiliary battery's aging state, ensuring a minimum cumulative charge current is achieved by determining a reference cumulative charge current amount and adjusting the charging method accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If constant voltage charging method is used for auxiliary battery, then charging speed is improved, but charge current amount decreases when battery ages due to increased internal resistance
Solution Approach 1:
The patent dynamically switches between constant voltage charging and constant current charging methods based on the auxiliary battery's aging state. When the battery is young, constant voltage charging is used for speed. When the battery ages and internal resistance increases, the system transitions to constant current charging to maintain sufficient charge current amount, thus adapting the charging strategy to the battery's condition.
Solution Approach 2:
The patent changes the charging parameter from constant voltage to constant current based on the battery's aging state. By detecting the battery's state of charge and aging level, the system adjusts the charging method to maintain the charge current amount within a desired range, ensuring both charging efficiency and sufficient charge delivery to aged batteries.
2Reliability
If periodic charging is performed to maintain reference SOC, then battery startability is improved, but sufficient charge current cannot be secured when battery capacity is reduced due to aging
Solution Approach 1:
The patent implements a feedback mechanism that monitors the auxiliary battery's state of charge, cumulative charge current amount, and aging state. Based on this feedback, the system determines whether to apply constant voltage or constant current charging, ensuring that the charge current amount meets the desired threshold while maintaining the battery's startability capability.
Solution Approach 2:
The charging strategy dynamically adapts to the battery's aging state. The system transitions from a fixed periodic charging approach to a dynamic charging control that adjusts the charging method (constant voltage or constant current) based on real-time battery conditions, ensuring sufficient charge current delivery even as the battery ages.
3Productivity
If constant voltage charging is applied for predetermined time, then charging efficiency is improved, but cumulative charge current amount becomes insufficient when battery internal resistance increases due to aging
Solution Approach 1:
The patent changes the charging parameter from constant voltage to constant current when the battery's internal resistance increases due to aging. This parameter change ensures that the cumulative charge current amount reaches the desired level while maintaining charging efficiency, as the constant current method compensates for the increased internal resistance in aged batteries.
Solution Approach 2:
The system dynamically selects the charging method based on the battery's aging state and real-time performance. By transitioning from constant voltage to constant current charging when needed, the system maintains both charging efficiency and sufficient cumulative charge current delivery, adapting to the battery's changing characteristics over time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively secures a desired cumulative charge current for the auxiliary battery, maintaining vehicle startability even when the battery has aged, by switching to constant current charging if the battery's internal resistance increases, thus preventing a shortage of charge current.
Implementation Method 1
a low voltage DC-DC converter (LDC) stepping down the voltage of the main battery and providing the stepped-down voltage to the auxiliary battery
Implementation Method 2
a low-voltage auxiliary battery supplying electric power to an electronic/electric load of the vehicle
Data Source
AI summary
A supplementary charging system for an auxiliary battery of an eco-friendly vehicle includes: a main battery; an auxiliary battery having a voltage lower than a voltage of the main battery; a low voltage DC-DC converter (LDC) stepping down the voltage of the main battery and providing the stepped-down voltage to the auxiliary battery; and a controller configured to select, when a periodic charge time of the auxiliary battery arrives, either a constant voltage charging method or a constant current charging method as a charging method based on an aging state of the auxiliary battery, and control the LDC to charge the auxiliary battery with a constant voltage or a constant current based on the selected charging method for a predetermined reference time. The controller terminates the charging when a cumulative charge current amount is greater than or equal to a predetermined reference cumulative charge current amount.