Stacked Pouch-Cell Battery Pack for Controlled Swelling and Venting
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Solution Overview
Problem
Conventional battery packs using cylindrical Li-Ion cells face issues with swelling and venting, leading to reduced battery life and potential mechanical conflicts with power tools due to uncontrolled expansion.
Innovation Solution
The use of non-cylindrical pouch cells with a firm internal plate structure and expandable housing, along with features like notches or holes in the sealed edge for controlled venting, ensures that the battery pack can accommodate cell swelling without interfering with the power tool and maintains its geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional cylindrical Li-Ion cells are used in battery packs, then the battery structure is simple and easy to manufacture, but the cells swell and vent uncontrolledly leading to mechanical conflicts with power tools
Solution Approach 1:
The battery pack is divided into multiple independent frame assemblies, each containing individual pouch cells. This segmentation allows each cell to be contained and managed separately, preventing uncontrolled swelling from affecting the entire battery pack or causing mechanical conflicts with the power tool.
Solution Approach 2:
A firm internal plate structure is introduced as an intermediary between the pouch cells and the external environment. This plate structure provides a rigid framework that constrains cell expansion while allowing controlled venting through notches or holes in the sealed edge, preventing direct mechanical conflict between swelling cells and the power tool housing.
2Shape
If pouch cells with firm internal plate structure are used, then cell swelling is controlled and geometry is maintained, but the manufacturing process becomes more complex
Solution Approach 1:
The pouch cells are pre-formed with notches or holes in the sealed edge during cell manufacturing, before assembly into the battery pack. This preliminary action ensures that controlled venting pathways are already in place, eliminating the need for complex post-assembly modifications and simplifying the overall manufacturing process.
Solution Approach 2:
The battery pack combines pouch cells with a firm internal plate structure to create a composite assembly. This composite structure integrates the flexibility of pouch cells with the rigidity of the plate structure, maintaining stable geometry while simplifying manufacturing by using standardized components that can be assembled through standardized processes.
3Quantity of substance
If cells are allowed to swell freely, then cell capacity is maximized, but mechanical conflicts with power tools occur and battery life is reduced
Solution Approach 1:
The firm internal plate structure with controlled venting pathways is installed before cell swelling occurs. This preliminary anti-action prevents uncontrolled expansion by providing predetermined venting routes, allowing the cells to reach their full capacity while preventing the mechanical conflicts that would otherwise reduce battery life.
Solution Approach 2:
The potential harmful effect of cell swelling is converted into a beneficial controlled venting mechanism. By incorporating notches or holes in the sealed edge of the pouch cells, the natural swelling pressure is directed through controlled pathways, transforming what would be a harmful uncontrolled expansion into a beneficial pressure relief mechanism that extends battery life while maintaining full capacity.
Data Source
AI summary
A battery pack includes a battery cell holder, where the battery cell holder includes multiple frames with each of the frames defining a cavity and adjacent frames connected to each other. The battery pack includes at least one pouch battery cell disposed in the cavity of each of the frames, where pouch battery cells disposed in adjacent frames are electrically connected to each other. The multiple frames are arranged in a stacked configuration.