Compliant Heat Exchanger for Battery Stack Thermal Management
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Solution Overview
Problem
Rechargeable batteries, such as lithium-ion cells used in electric vehicles, generate significant heat that needs to be dissipated efficiently, but existing heat exchangers struggle to maintain consistent contact and effective heat transfer due to thermal expansion and contraction.
Innovation Solution
A dimensionally compliant heat exchanger structure, typically a corrugated or resilient fin plate, is placed between battery stacks to compress under expansion and expand under contraction, ensuring continuous thermal contact and efficient heat transfer through fluid flow passages, using materials like aluminum or stainless steel and secured via brazing, welding, or mechanical interlocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid heat exchanger structure is used, then structural stability is improved, but thermal contact consistency deteriorates due to battery stack expansion and contraction
Solution Approach 1:
The heat exchanger structure transitions from a rigid static design to a dynamic compliant design that can adapt its shape and dimensions in response to battery stack thermal expansion and contraction. The compliant structure maintains continuous thermal contact throughout the thermal cycling process, resolving the contradiction between structural stability and thermal contact consistency.
Solution Approach 2:
The heat exchanger is designed with variable geometric parameters that allow it to change its physical dimensions and configuration in response to thermal conditions. This parameter adaptability enables the structure to maintain optimal thermal contact with the battery stack across different temperature states, overcoming the limitation of rigid structures.
2Reliability
If a compliant heat exchanger structure is used, then thermal contact consistency is improved, but structural strength deteriorates
Solution Approach 1:
The heat exchanger employs composite material construction that combines materials with different mechanical and thermal properties. This composite approach enables the structure to achieve both compliance for maintaining thermal contact and sufficient strength for structural integrity, resolving the contradiction between these two requirements.
Solution Approach 2:
The heat exchanger incorporates curved or corrugated geometric features that provide inherent compliance and flexibility. These curved structures can deform elastically to maintain contact with the battery stack while distributing stresses, thereby achieving both thermal contact consistency and structural strength.
3Productivity
If the heat exchanger is designed for high heat transfer efficiency, then heat dissipation performance is improved, but adaptability to thermal expansion deteriorates
Solution Approach 1:
The heat exchanger design integrates dynamic adaptability features that allow the structure to adjust its configuration in response to thermal expansion. This dynamic capability ensures that high heat transfer efficiency is maintained across varying thermal conditions, as the structure continuously optimizes its thermal contact with the battery stack.
Solution Approach 2:
The heat exchanger is divided into multiple segments or sections that can independently deform and adapt to thermal expansion. This segmentation allows each section to maintain optimal thermal contact while accommodating overall dimensional changes, preserving heat dissipation performance across the entire structure.
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 heat exchanger maintains uninterrupted heat transfer across a range of temperatures, effectively dissipating heat from battery stacks by accommodating thermal expansion and contraction, ensuring reliable operation and prolonged battery life.
Implementation Method 1
the heat exchanger structure being dimensionally compliant to compress under expansion of the first and second battery stacks and expand under subsequent contraction of the first and second battery stacks
Implementation Method 2
efficient heat transfer through fluid flow passages
Implementation Method 3
heat exchanger structure...defining one or more fluid flow passages
Data Source
AI summary
A heat exchanger structure for use in a battery unit that comprises a first battery stack comprising a plurality of battery cells and a second battery stack comprising a plurality of battery cells. The heat exchanger structure is disposed between opposing surfaces of the first battery stack and the second battery stack and defines one or more fluid flow passages, the heat exchanger structure being dimensionally compliant to compress under expansion of the first and second battery stacks and expand under subsequent contraction of the first and second battery stacks.