Battery Pack Pressure Compensation for Dielectric Fluid Expansion
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Solution Overview
Problem
Conventional battery modules with cylindrical cells face challenges in packing efficiency due to their curved shape and require complex cell support structures for retention and cooling, which complicates space management and cooling efficiency.
Innovation Solution
A battery pack design featuring a modular housing with a bladder system that accommodates volume changes and a thermal management system using engineered fluids for active and passive cooling, along with bus bar assemblies for efficient electrical connections, to enhance packing efficiency and cooling while minimizing space occupation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cylindrical cells are used in battery modules, then ease of manufacturability and stability are improved, but packing efficiency deteriorates due to their curved shape
Solution Approach 1:
The patent employs a flexible bladder system that can deform to conform to the curved surfaces of cylindrical battery cells. The bladder includes a flexible membrane that makes direct contact with the cell exterior surfaces, allowing efficient space utilization while maintaining cell stability and ease of manufacture.
2Reliability
If cell support structures are provided to retain cells and provide cooling, then cell retention and cooling are improved, but device complexity and space occupation increase
Solution Approach 1:
The patent combines multiple functions into a single integrated bladder system. The bladder simultaneously provides mechanical retention of cylindrical cells through its flexible conforming structure, active cooling through embedded coolant channels, and pressure management through fluid compensation. This eliminates the need for separate support structures, reducing overall device complexity while maintaining reliable cell retention and effective cooling.
3Temperature
If cell support structures with sufficient bulk are provided for cooling, then cell cooling is improved, but packing efficiency deteriorates due to increased space occupation
Solution Approach 1:
The patent utilizes a hydraulic cooling system where a fluid-filled bladder with embedded coolant channels provides active cooling to cylindrical cells. The flexible bladder conforms to the cell geometry, allowing efficient heat transfer through direct contact without requiring bulky rigid cooling structures. This hydraulic approach enables effective cell cooling while minimizing space occupation and maximizing packing efficiency.
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 design achieves a stable, ordered arrangement of cylindrical cells with improved packing efficiency and effective cooling, reducing manufacturing complexity and costs while maintaining high electrical performance.
Implementation Method 1
the bladder expands and contracts to accommodate volume changes of the first fluid due to changes in the environment of the battery pack
Implementation Method 2
The battery pack housing is filled with a first fluid that is dielectric
Implementation Method 3
a second bore that opens on a side surface of the vent block and includes a first vent that is fluid impermeable and air impermeable, and opens at a predetermined fluid pressure
Data Source
AI summary
A battery pack includes a battery pack housing that is flooded with a dielectric fluid and sealed. The battery pack includes a vent block disposed on an outer surface of the housing, and a bladder disposed inside the housing that communicates with the vent block via a fitting. The bladder interior space includes air, and the bladder expands and contracts to accommodate volume changes of the dielectric fluid due to changes in the environment of the battery pack.