EV Battery Pack Lid Compression for Cell Expansion Control
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Solution Overview
Problem
Existing battery pack designs for electric vehicles face challenges in providing lightweight protection while maintaining structural integrity and counterbalancing volumetric expansion of battery cells, which affects lifespan and energy density.
Innovation Solution
A battery pack module design featuring a battery housing with a lid that applies pressure to the cells towards the center using a protrusion, combined with a thermoplastic material and thermal management system, along with a frame that includes shock and impact absorption means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aluminum or high strength steel designs are used for battery pack frames, then structural integrity and protection during impact are improved, but weight increases
Solution Approach 1:
The battery pack housing combines thermoplastic material with reinforcement elements (fiberglass, carbon fiber, or metal inserts) to create a composite structure that achieves high strength-to-weight ratio, providing structural integrity while minimizing weight compared to traditional aluminum or steel frames
Solution Approach 2:
The battery pack frame is divided into modular components including bottom enclosure, lid, and reinforcement elements that can be separately optimized and assembled, allowing strategic placement of high-strength materials only where structurally necessary
2Duration of action of stationary object
If compression force is applied to battery cells, then cell expansion during charging and aging is counterbalanced and lifetime is extended, but device complexity increases
Solution Approach 1:
The compression mechanism is integrated into the battery pack housing structure itself, where the lid and bottom enclosure act as compression plates, and the protrusion on the lid combines sealing and compression functions, eliminating the need for separate compression devices
Solution Approach 2:
The protrusion on the lid automatically applies compression force to the battery cells as the lid is closed and secured, providing self-regulating compression that adapts to cell expansion during charging and aging without requiring external control systems
3Quantity of substance
If the protrusion presses the battery assembly towards the center, then energy density is enhanced and cell expansion is counterbalanced, but manufacturing precision requirements increase
Solution Approach 1:
The protrusion is designed with specific geometric features (such as tapered surfaces or compliant materials) that concentrate compression force precisely at the contact point with the battery cell, ensuring effective local pressure application even with moderate manufacturing tolerances
Solution Approach 2:
The protrusion geometry and material properties are optimized to provide compliant compression that adapts to variations in battery cell dimensions and positioning, reducing the impact of manufacturing precision variations on overall system performance
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 effectively counterbalances cell expansion, enhances energy density, and extends battery life while reducing weight and improving thermal management and impact resistance.
Implementation Method 1
the lid comprises at least a protrusion, the protrusion is positioned in order to press the battery assembly towards the center of the module
Implementation Method 2
the battery housing may comprise thermal transfer means configured to dissipate the heat coming from the battery to the external environment of the battery pack
Implementation Method 3
a twin walled enclosure can be used to allow circulation of a cooling fluid between the two walls
Data Source
AI summary
A battery pack comprising: a battery comprising at least one battery cell, connectors and heat exchanger means, and a battery housing comprising: a bottom enclosure comprising at least a base and an upstanding peripheral wall, the bottom enclosure is suitable to contain the battery, a lid suitable for closing the bottom enclosure, and fixation means suitable to maintain the lid on the bottom enclosure in order to close the battery pack housing, characterized in that the lid comprises at least a protrusion, the protrusion is positioned in order to press the battery assembly towards the center of the module, wherein the battery is contained inside the bottom enclosure and the lid is covering the bottom enclosure and retained by the fixation means inside the battery housing, adjacent to the wall of the bottom enclosure and the battery.