EV Battery Current Balancing via Temperature-Based Resistance Control
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Solution Overview
Problem
Temperature differences between battery groups in electric vehicles lead to performance deterioration and unbalanced deterioration, affecting discharge and charge capabilities and limiting battery output.
Innovation Solution
A battery control apparatus with a processor that adjusts the resistance of a variable resistor based on temperature differences between battery groups, ensuring even current flow and reducing temperature disparities, thereby maintaining balanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a variable resistance circuit is used to balance current flow between battery groups, then current distribution is improved, but device complexity increases
Solution Approach 1:
The variable resistance circuit acts as an intermediary component between the two battery groups, adjusting current flow to balance SOC differences. The resistance value is dynamically controlled based on temperature differences and SOC states, serving as a mediator to achieve current distribution balance without requiring complex control systems.
2Temperature
If resistance adjustment is applied to balance battery groups, then temperature difference is reduced, but energy loss increases
Solution Approach 1:
The variable resistance circuit is activated only partially - specifically when temperature difference exceeds a threshold and SOC difference is within a predetermined range. This partial action approach balances temperature differences when necessary while avoiding continuous energy loss from resistance adjustment, thus optimizing the trade-off between temperature balancing and energy efficiency.
3Power
If variable resistor is used for current balancing, then battery output is enhanced, but manufacturing cost increases
Solution Approach 1:
The variable resistance circuit changes its resistance parameter dynamically based on operating conditions (temperature difference and SOC state). This parameter change capability allows the system to enhance battery output by optimizing current distribution under different conditions, while the relatively simple variable resistance mechanism keeps manufacturing costs lower than more complex active balancing systems.
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 solution effectively reduces performance degradation and maintains balanced battery performance by evening out current flow and heat generation between battery groups, enhancing overall battery output and extending lifespan.
Implementation Method 1
The variable resistor is electrically coupled to the battery. The processor is configured to execute a resistance adjustment process, based on a difference between a temperature of the first battery group and a temperature of the second battery group. The resistance adjustment process is configured to control the variable resistor to cause a current per unit capacity of the first battery group and a current per unit capacity of the second battery group to be evenly closer to each other
Data Source
AI summary
A battery control apparatus is to be mounted on an electric vehicle and includes a processor. The processor is configured to control a variable resistor of the electric vehicle. The processor is configured to execute a resistance adjustment process, based on a difference between a temperature of a first battery group of the electric vehicle and a temperature of a second battery group of the electric vehicle. The resistance adjustment process is configured to control the variable resistor to cause a current per unit capacity of the first battery group and a current per unit capacity of the second battery group to be evenly closer to each other than when the resistance adjustment process is unexecuted. The processor is configured to refrain from executing the resistance adjustment process upon driving of the electric vehicle in which electric power is to be outputted from a battery of the electric vehicle.