Cell-Level Battery Thermal Management via Internal Resistance Estimation
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Solution Overview
Problem
Existing battery thermal management systems for electric vehicles rely on coarse-grained controls that either heat or cool all battery cells simultaneously, leading to inefficiency and safety margins, failing to optimize temperature within the normal operational range for enhanced performance and reliability.
Innovation Solution
A cyber-physical battery thermal management system that estimates internal resistance and open-circuit voltage for each cell, determines target temperatures, and selectively controls coolant flow to manage temperature at the cell level, optimizing performance and extending operation time without compromising reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coarse-grained thermal control is used to heat or cool all battery cells simultaneously, then thermal management coverage is ensured, but system efficiency deteriorates and unnecessary energy consumption occurs
Solution Approach 1:
The patent divides the battery pack into multiple temperature zones with independent thermal control. Each zone has its own heating and cooling capabilities, allowing selective thermal management based on actual temperature distribution. This segmentation enables the system to apply thermal control only where needed rather than uniformly across all cells, thereby maintaining reliability while reducing energy consumption.
Solution Approach 2:
The system implements differentiated thermal control strategies for different spatial locations within the battery pack. By measuring temperature at multiple points and identifying hot or cold zones, the system applies heating or cooling only to specific local areas rather than the entire pack. This local quality approach ensures adequate thermal management coverage while minimizing unnecessary energy expenditure in already-adequate temperature regions.
2Reliability
If coarse-grained thermal control is used to maintain normal operational temperature range, then basic thermal safety is ensured, but operational efficiency deteriorates due to lack of optimization within normal range
Solution Approach 1:
The patent implements dynamic thermal control that continuously adjusts heating and cooling based on real-time temperature measurements and power requirements. Within the normal operational temperature range, the system dynamically optimizes cell temperatures to maximize power delivery efficiency. This dynamic adjustment allows the system to maintain thermal safety while actively optimizing operational efficiency by keeping cells at optimal temperatures for power delivery rather than merely maintaining a static temperature range.
Solution Approach 2:
The system uses temperature sensors to continuously monitor battery cell temperatures and feeds this information back to the thermal management controller. Based on this feedback, the system adjusts heating and cooling operations to optimize cell temperatures for maximum power delivery. This feedback mechanism enables the system to maintain thermal safety while improving operational efficiency by responding to actual thermal conditions and power requirements in real-time.
3Productivity
If cell-level selective thermal control is implemented to optimize individual cell temperature, then operational efficiency improves, but device complexity increases
Solution Approach 1:
The patent divides the battery pack into multiple temperature zones with independent thermal control capabilities. Each zone can be independently heated or cooled based on its specific thermal conditions and power requirements. This segmentation strategy enables cell-level selective thermal control to optimize operational efficiency while managing complexity by grouping cells into zones rather than controlling each cell individually, thus reducing the number of control elements needed.
Solution Approach 2:
The thermal management system is designed to perform multiple functions: cooling overheated cells, heating under-temperature cells, and optimizing cell temperatures for maximum power delivery. By creating a universal thermal control platform that can adapt to different thermal conditions and power requirements, the system achieves cell-level optimization without proportionally increasing complexity. The same hardware infrastructure supports multiple operational modes and strategies.
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 improves operation time by up to 58.4% and reduces energy dissipation, maintaining battery health and preventing malfunctions or explosions by dynamically controlling temperature based on power requirements and state of charge.
Implementation Method 1
controlling a flow of coolant adjacent to the given battery cell based on the target temperature for the given battery cell
Implementation Method 2
controlling a flow of coolant adjacent to the given battery cell
Data Source
AI summary
A method includes estimating, for a given battery cell of a plurality of battery cells, an internal resistance, estimating, for the given battery cell, an open-circuit voltage, determining a target output voltage for the given battery cell, determining a target discharge current for the given battery cell, determining a target internal resistance for the given battery cell based on the estimated open-circuit voltage for the given battery cell, the target output voltage for the given battery cell, and the target discharge current for the given battery cell, determining a target cell temperature for the given battery cell based on the target internal resistance for the given battery cell, and controlling a flow of coolant adjacent to the given battery cell based on the target temperature for the given battery cell.