Cell-Level Battery Heat Measurement Using Direct-to-Air Heat Pumps
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Solution Overview
Problem
Existing battery monitoring systems fail to accurately measure and control heat generation in electrochemical battery cells, leading to performance degradation and potential thermal runaway, especially in lithium-ion batteries used in high-energy devices and electric vehicles.
Innovation Solution
The implementation of direct-to-air heat pumps, specifically thermoelectric assemblies (TEAs) with solid-state thermoelectric modules, heat sinks, and rotary fans, in conjunction with temperature and heat flux sensors, to measure and manage heat generation in battery cells, ensuring accurate heat flux distribution and maintaining constant pressure for effective thermal regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional battery monitoring systems are used, then the system structure remains simple, but heat generation measurement accuracy is insufficient leading to performance degradation and thermal runaway risks
Solution Approach 1:
The battery pack is divided into multiple battery cells, and each cell is equipped with its own heat pump device and temperature sensor. This segmentation allows for cell-level heat generation measurement and independent thermal management, significantly improving measurement accuracy while enabling localized control to mitigate the complexity increase.
Solution Approach 2:
Heat pump devices are introduced as intermediary components between the battery cells and the thermal environment. These heat pumps actively transfer heat from battery cells to the surrounding air, enabling precise measurement of heat generation through the heat pump's thermal performance while maintaining system manageability through a standardized intermediary interface.
2Adaptability or versatility
If battery cells operate outside the well-defined temperature range, then the system operation freedom increases, but battery performance degrades and service life shortens
Solution Approach 1:
Temperature sensors continuously monitor the temperature of each battery cell and provide feedback to the control system. The control system processes this temperature information and adjusts the heat pump operation accordingly, creating a closed-loop feedback mechanism that maintains battery cells within the optimal temperature range while allowing flexible operation under varying environmental conditions.
Solution Approach 2:
The system dynamically changes operational parameters (heat pump power, fan speed) based on real-time temperature measurements to maintain battery cells within the optimal temperature range. This parameter adjustment allows the battery system to adapt to different ambient temperatures and operating conditions while ensuring reliable performance and extended service life.
3Device complexity
If excessive battery temperatures are allowed, then the system simplicity is maintained, but thermal runaway occurs
Solution Approach 1:
Heat pump devices are installed on each battery cell to proactively remove heat before dangerous temperature accumulation occurs. The system continuously monitors temperature and activates heat pumping action in advance, preventing thermal runaway conditions from developing while maintaining a relatively simple device architecture through preventive rather than reactive thermal management.
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 solution enables precise measurement and control of heat generation, extending battery life, preventing thermal runaway, and ensuring reliable operation in various applications, including electric vehicles and portable electronics.
Implementation Method 1
a solid-state TEM operates based on the Peltier effect, with an electrical current flowing through the TEM inducing a current-dependent temperature gradient, and vice versa. The generated temperature gradient in turn drives heat from one side of the solid-state TEM to another.
Implementation Method 2
a corresponding heat sink, and a rotary fan or another application-suitable thermal regulator device
Data Source
AI summary
A battery electric device includes a battery cell, e.g., a pouch, prismatic, or cylindrical cell, connectable to an electric load, and a direct-to-air thermoelectric assembly (TEA) or another heat pump connected to a surface of the cell. A pressure control device maintains constant pressure on the cell surface when the cell is connected to the load. Connection to the load causes the TEA/heat pump to pump heat from the cell. A sensor, e.g., thermocouple(s) and/or heat flux sensor(s), generate an output voltage signal indicative of the quantity of heat. A battery system includes the device and a processor in communication with the cell, the load, and the power supply. The processor generates an electronic control signal in response to the quantity of heat.