Traction Battery Self-Heating via Voltage Cycling
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Solution Overview
Problem
Traction batteries in automotive vehicles face limited charging capabilities at low temperatures due to diffusive characteristics, leading to battery degradation and capacity losses through lithium plating and increased cell impedance.
Innovation Solution
A control module cycles the traction battery at a first charge/discharge profile based on initial temperature and monitors discharge voltage, switching to a second profile if a threshold change occurs, generating heat within the battery to maintain optimal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery is charged at low temperatures, then charging capability is limited, but battery degradation and capacity losses occur through lithium plating
Solution Approach 1:
The system performs preliminary heating of the battery using resistive heating elements before charging begins. Temperature sensors monitor the battery temperature, and when it falls below the threshold, the control module activates the heating elements to raise the temperature to an optimal charging range, preventing lithium plating before it occurs
Solution Approach 2:
The system dynamically adjusts charging parameters based on temperature conditions. When the battery temperature is below the threshold, the control module reduces charging current or voltage to prevent lithium plating. Once the temperature reaches the optimal range, normal charging parameters are restored, thus preventing degradation while maintaining charging capability
2Productivity
If the battery temperature is increased to improve charging capability, then charging performance improves, but thermal management complexity increases
Solution Approach 1:
The battery pack includes integrated resistive heating elements that use the battery's own electrical system to generate heat. The control module activates these heating elements using controlled current flow through the battery cells, allowing the battery to heat itself without requiring external heating devices or complex thermal management infrastructure
Solution Approach 2:
The control module serves multiple functions: it monitors battery temperature, controls charging parameters, and activates heating elements. This multi-functional approach consolidates thermal management tasks into existing control infrastructure, avoiding the need for separate dedicated thermal management 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
This method effectively generates heat within the battery, enhancing charging capabilities and preventing degradation by managing discharge voltage and temperature, thus maintaining battery performance at low temperatures.
Implementation Method 1
cycling the power storage unit at a first charge/discharge profile, monitoring the discharge voltage of the power storage unit and cycling the power storage unit at a second charge/discharge profile if a change in the discharge voltage of the power storage unit exceeds a threshold thereby generating heat within the power storage unit
Data Source
AI summary
A battery control module monitors discharge voltages associated with a traction battery of an automotive vehicle. The battery control module cycles the traction battery at a discharge-voltage dependent charge/discharge profile to generate heat within the traction battery.