Traction Battery Cell Holder Layout for Uniform Stack Compression
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Solution Overview
Problem
Existing traction battery pack systems face challenges in efficiently managing compression and thermal management across cell holders, which can lead to uneven cell compression and potential thermal issues during battery operation.
Innovation Solution
The system employs a plurality of cell holders with four walls, each holding a group of battery cells, and a tensioning member such as a tensioning rod with radially extending bores to secure the cell holders. This configuration allows for adjustable compression and thermal management by varying the distance between cell holders and using adhesive to bond them to the tensioning rod.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If cell holders are rigidly fixed to maintain structural stability, then structural stability is improved, but uniform cell compression is worsened
Solution Approach 1:
The cell holders are designed with dynamic positioning capability along the tensioning member, allowing them to move axially to achieve uniform compression distribution. The tensioning member enables controlled movement while maintaining overall structural stability, resolving the contradiction between rigidity and compression uniformity.
2Quantity of substance
If cell holders are positioned closely together to maximize battery density, then energy density is improved, but thermal management is worsened
Solution Approach 1:
The cell holders are designed with differentiated local properties: the axially facing walls provide compression and structural support, while the configurations allow spacing variations for thermal management. This enables different regions of the battery pack to have optimized characteristics for either density or thermal management based on local requirements.
3Strength
If compression force is increased to improve cell contact, then cell contact is improved, but thermal event risks are worsened
Solution Approach 1:
The system provides dynamic compression control where the tensioning member can apply compressive forces that are sufficient for good cell contact but controllable to prevent excessive forces. The cell holders can move along the tensioning member to maintain optimal contact pressure without creating dangerous compression levels that could trigger thermal events.
Data Source
AI summary
A traction battery pack system includes cell holders and battery cell groups disposed along a cell stack axis. Each of the battery cell groups is housed in one of the cell holders. The cell holders each include an axially facing wall disposed between two of the battery cell groups in the plurality of battery cell groups. A tensioning member holds the cell holders along the cell stack axis. A positioning of the cell holders relative to the tensioning member is based, at least in part, on a pressure on the battery cell groups at the position.