Modular Heat Flow Calorimeter for Battery Thermal Runaway Testing
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Solution Overview
Problem
Existing systems for battery characterization, particularly for high energy density systems like lithium batteries, face challenges in accurately measuring heat generation and thermal characteristics during thermal runaway, as they may not represent real-world conditions, and lack flexibility and cost-effective maintenance options for larger testing systems.
Innovation Solution
A heat flow calorimeter system is developed to accommodate sealed pressure vessels, allowing for isothermal testing of battery cells, with a robust sample environment and sensitive detection capabilities, enabling the measurement of heat flow from multiple surfaces and supporting various battery configurations, and featuring modular design for easy maintenance and repair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Accelerating Rate calorimetry (ARC) methodology is used to characterize battery thermal runaway, then thermal runaway conditions can be achieved and recorded, but the increasing heat may not be representative of real world conditions and may impact data collection accuracy
Solution Approach 1:
The patent transitions from ARC methodology with increasing temperature steps to isothermal calorimetry where the temperature is held constant. This parameter change allows the system to measure heat generation under conditions that better represent real-world battery operation while maintaining the ability to detect thermal runaway events through heat flow measurements rather than temperature escalation.
2Measurement precision
If isothermal calorimetry methodology is used to control ambient temperature tightly during testing, then accurate evaluation of heat generated from chemical reactions can be achieved, but the system lacks the robust sample environment needed for destructive events
Solution Approach 1:
The patent merges two previously separate systems: a robust bomb calorimeter designed for destructive events and a sensitive isothermal calorimeter for accurate heat measurement. The resulting hybrid system combines the strong containment and safety features of the bomb calorimeter with the precise isothermal temperature control and heat flow detection capabilities of the isothermal calorimeter, enabling both accurate measurement and safe handling of destructive events.
Solution Approach 2:
The modified calorimeter system achieves multi-functionality by being capable of both isothermal measurements for normal operation characterization and destructive event testing for safety assessment. The system can accommodate different sample configurations and testing methodologies, making it a universal platform for comprehensive battery characterization across multiple test types.
3Adaptability or versatility
If the calorimeter system is designed to accommodate larger battery cells and various configurations, then testing flexibility is improved, but system complexity and maintenance cost increase
Solution Approach 1:
The calorimeter system is divided into modular components including the bomb calorimeter chamber, isothermal control system, heat flow detection system, and data acquisition system. Each module can be independently configured, maintained, or replaced. The system can accommodate different battery cell sizes and configurations by adjusting sample holders and testing protocols without requiring complete system redesign, thereby managing complexity while maintaining versatility.
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 system provides accurate characterization of heat generation and thermal efficiency of battery cells, enabling effective risk mitigation and data collection before, during, and after destructive events, while allowing for flexible and cost-effective testing of larger samples with improved maintenance capabilities.
Implementation Method 1
each of the six surfaces of the sample cell can be provided a thermal conduction pathway of least resistance that is isolated from the other five surfaces and channeled through a plurality of thermopiles
Implementation Method 2
channeled through a plurality of thermopiles
Data Source
AI summary
Apparatus and methods are provided for providing flexible and repairable testing capabilities, including destructive testing, for systems that generate or absorb heat such as energy storage systems. One embodiment can include a temperature bath structure adapted to contain and maintain a fluid bath at a predetermined temperature, an outer containment structure adapted to insert into the temperature bath structure, heat sinks, thermal sensor assemblies, and an internal containment structure where the thermal sensor assemblies, heat sinks removeably attach to different sections of the inner containment structure so as to measure heat flow into or out of the inner containment structure's different sections, and a test cell enclosure which is adapted to contain forces and output from destructive testing of samples. Embodiments of the invention enable rapid insertion/removal of samples as well as replacement of sections of the system including thermal sensor assemblies as well as enabling separate thermal measurements associated with different sections of a sample under test.