Auxiliary Battery Temperature Control via DC Converter Current
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Solution Overview
Problem
Auxiliary batteries in eco-friendly vehicles experience low charge and discharge efficiency at low or high temperatures due to chemical properties, limiting the effectiveness of existing control techniques.
Innovation Solution
A system and method that uses a DC converter and controller to rapidly adjust the temperature of the auxiliary battery by setting the charging current to a maximum value at low temperatures and reducing it to zero at high temperatures, utilizing a data map to derive optimal charging currents based on temperature and charge state, thereby maximizing heat generation at low temperatures and suppressing heat generation at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the auxiliary battery operates at low temperature below a predetermined temperature or at high temperature above a predetermined temperature, then the chemical reactions occur more rapidly, but the charge and discharge efficiency becomes very low due to chemical properties
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the charging current based on battery temperature. When temperature is below a first threshold, the controller increases charging current to generate heat and raise temperature. When temperature exceeds a second threshold, the controller reduces or stops charging current to prevent overheating. This adaptive parameter adjustment resolves the contradiction between maintaining efficient chemical reactions and preventing temperature-induced efficiency loss
Solution Approach 2:
The patent implements feedback control by continuously monitoring battery temperature and adjusting the charging current accordingly. The controller receives temperature information from the battery and modifies the charging parameters in real-time. This closed-loop feedback mechanism ensures the battery operates within optimal temperature ranges, resolving the efficiency degradation caused by extreme temperatures
2Speed
If the charging current is increased to maximum value to rapidly increase battery temperature, then the temperature rises quickly to improve efficiency, but the heat generation may cause overheating if not properly controlled
Solution Approach 1:
The patent applies dynamics by making the charging current adjustable and responsive to real-time temperature conditions. Rather than using a fixed current value, the system dynamically modifies the charging current based on whether the battery temperature is below the first threshold, between thresholds, or above the second threshold. This dynamic adjustment enables rapid temperature increase when needed while preventing overheating, resolving the contradiction between speed of temperature adjustment and overheating risk
Solution Approach 2:
The patent applies preliminary anti-action by implementing preventive measures before overheating occurs. The controller monitors temperature continuously and reduces or stops charging current when the temperature approaches the second threshold, preventing the harmful effect of overheating before it occurs. This proactive control resolves the contradiction by enabling fast temperature adjustment while preemptively avoiding overheating risks
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
This approach allows the auxiliary battery to quickly escape temperature ranges with low efficiency, enhancing charge and discharge efficiency, improving fuel efficiency and durability of the vehicle.
Implementation Method 1
a high-voltage battery that stores high-voltage electrical energy to drive the electric motor, a low-voltage auxiliary battery that supplies electric power to an electric load of the vehicle, and a low-voltage DC converter (LDC) that down-converts the voltage of the high-voltage battery into the voltage of the auxiliary battery
Implementation Method 2
the auxiliary battery has very low charge and discharge efficiency at a low temperature below a predetermined temperature or at a high temperature above a predetermined temperature due to chemical properties
Data Source
AI summary
A method for controlling charge or discharge of a battery in a battery system including a DC converter down-converting an input voltage thereof and outputting an output, a battery connected to an output terminal of the DC converter, and an electric load connected to the output terminal of the DC converter and supplied with electric power from at least one of the DC converter and the battery, may include measuring a temperature of the battery, first controlling, by a controller, an output of the DC converter so that a charging current supplied to the battery from the DC converter becomes a preset maximum value, when the temperature of the battery is lower than a first predetermined temperature, and second controlling, by the controller, the output of the DC converter such that a current of the battery is substantially equal to zero, when the temperature of the battery is higher than a second predetermined temperature which is higher than the first predetermined temperature.