Battery Pack Pressure Release via Segmented Seal
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Solution Overview
Problem
Conventional vehicle installed battery packs lack a mechanism to safely discharge internal gases produced due to increased pressure, leading to potential rupture of the seal member and leakage.
Innovation Solution
A pressure release structure featuring a battery pack case with a deforming stepped portion and weakly joined areas, where internal pressure concentrates and causes the battery pack upper cover to deform, creating an opening for gas discharge without rupturing the cover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seal member is made hermetically sealed to ensure sealing performance, then sealing reliability is improved, but the ability to discharge internal gases is lost
Solution Approach 1:
The seal member is segmented into two distinct regions: a first seal region with high sealing performance for hermetic sealing, and a second seal region with lower sealing performance that serves as a gas discharge path. This segmentation allows the seal member to simultaneously maintain sealing integrity while providing a controlled mechanism for gas release when internal pressure rises.
Solution Approach 2:
Different regions of the seal member are assigned different sealing qualities: the first seal region maintains high sealing reliability for normal operation, while the second seal region is deliberately designed with lower sealing performance to allow gas discharge. This local differentiation enables the seal member to perform both hermetic sealing and pressure relief functions.
2Reliability
If the case chamber is hermetically sealed to prevent leakage, then sealing performance is improved, but gas discharge capability is reduced
Solution Approach 1:
The seal member is divided into functional segments: a first seal region for hermetic sealing and a second seal region for gas discharge. This segmentation enables the case chamber to maintain hermetic sealing under normal conditions while adapting to discharge gases when pressure increases, thus resolving the contradiction between sealing performance and gas discharge capability.
Solution Approach 2:
The potential harmful effect of gas accumulation is converted into a beneficial function by designing the second seal region to intentionally allow gas discharge. What could be a failure mode (gas buildup from overcharging) is transformed into a controlled safety mechanism through the differential sealing design.
3Ease of manufacture
If the seal member is made thin to reduce material usage, then manufacturing cost is reduced, but rupture resistance is weakened
Solution Approach 1:
The seal member employs local quality differentiation where the first seal region has sufficient thickness and strength for hermetic sealing, while the second seal region is designed with reduced thickness to facilitate gas discharge. This localized variation in material properties allows cost-effective manufacturing while maintaining necessary strength in critical sealing areas.
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
Effectively discharges internal gases to the outside through a separable opening, preventing seal member rupture and ensuring safe pressure relief.
Implementation Method 1
the internal pressure concentrates in a section protruding furthest to the case center side within the case structure, specifically, the deforming stepped portion of the battery pack upper cover
Implementation Method 2
the battery pack upper cover undergoes deformation in a direction that eliminates the height difference of the step in the heightwise direction
Data Source
AI summary
A vehicle installed battery pack is provided with a pressure release structure. The vehicle installed battery pack includes a battery pack case, a battery pack module. The battery pack case includes a battery pack lower frame and a battery pack upper cover. The battery pack module is disposed in the battery pack lower frame. The battery pack upper cover is securely joined to the battery pack lower frame via a seal member that extends continuously about an entire perimeter of respective outside peripheral edge portion of the battery pack upper cover. The battery pack upper cover includes a deforming stepped portion having a height difference at least in a heightwise direction; and a weakly joined portion having a lower joint strength than other joined portions being set in an area of the seal member extending continuously about the entire perimeter. The area corresponds to the deforming stepped portion.