Cylindrical Cell Holder Venting for Adjacent Cell Gas Isolation
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Solution Overview
Problem
Existing battery packs face challenges in preventing high-temperature and high-pressure gas from entering adjacent cell accommodation portions due to inaccuracies in processing the tab and closing wall, which can lead to heat transfer and pressure issues between cells.
Innovation Solution
A battery pack design featuring a cell holder with a bottom wall that includes a through hole and lid walls with annular walls, where the tab is welded to the electrode terminals through this hole, and a thin portion on the lid wall or tab that can be cleaved by gas pressure, directing it into an annular wall and preventing entry into adjacent cells, regardless of processing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a closing wall is provided between cell accommodation portions to prevent gas entry, then gas containment is improved, but processing accuracy requirements increase and manufacturing complexity worsens
Solution Approach 1:
The patent changes the physical state and properties of the bottom wall by introducing a thin portion with reduced thickness. This thin portion is designed to deform under gas pressure, transitioning from a rigid barrier to a flexible pressure-responsive element that directs gas flow away from adjacent cells.
Solution Approach 2:
The bottom wall's thin portion transforms from a static structural element to a dynamic component that responds to gas pressure. When gas pressure exceeds a threshold, the thin portion deforms and redirects gas flow, providing adaptive protection without requiring precise processing of the tab or closing wall.
2Strength
If the tab is made rigid to maintain structural strength, then mechanical strength is improved, but gas pressure penetration and processing accuracy tolerance worsen
Solution Approach 1:
The patent applies local quality by creating a thin portion with reduced thickness in a specific location of the bottom wall. This localized modification allows the majority of the tab to maintain its structural strength while the thin portion provides pressure-responsive gas redirection capability.
Solution Approach 2:
The bottom wall is segmented into different thickness regions, with the thin portion serving as a dedicated pressure relief and gas redirection mechanism. This segmentation allows the tab to fulfill both structural support and gas containment functions through different regions.
3Reliability
If the closing wall is made thicker to prevent gas entry, then gas containment is improved, but device complexity and manufacturing difficulty worsen
Solution Approach 1:
Instead of increasing the overall thickness of the closing wall, the patent changes the thickness parameter locally by creating a thin portion in the bottom wall. This approach simplifies the overall structure while achieving gas containment through pressure-responsive deformation rather than sheer mass.
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
This design effectively prevents high-temperature and high-pressure gas from entering adjacent cell accommodation portions, ensuring reliable gas containment and reducing the risk of heat transfer between cells, regardless of the processing accuracy of the tab and closing wall.
Implementation Method 1
gas ejected from the cylindrical cell cleaves the thin portion and moves into the annular wall
Data Source
AI summary
A battery pack is provided and includes a plurality of cylindrical cells arranged in a manner that a plurality of electrode terminals face a same direction, a cell holder made from resin that holds arrangement of a plurality of the cylindrical cells, a tab extending in a planar direction parallel to a direction orthogonal to a longitudinal direction of the cylindrical cell, and a case. The cell holder includes a holder main body in which a plurality of cell accommodation portions are provided in the planar direction and a bottom wall extending in the planar direction, and a through hole penetrating the bottom wall, the bottom wall includes a plurality of lid walls covering the cell accommodation portion, and a plurality of annular walls, the tab includes a plurality of welded portions which are welded to the electrode terminal through the through hole, a wiring portion that extends in the planar direction from the welded portion and connects the welded portions to each other, at least one of the lid wall and the wiring portion is provided with a thin portion having small thickness in the longitudinal direction, and the thin portion is arranged on an inner side of the annular wall as viewed from the longitudinal direction.