Tool Battery Pack Waterproof Sealing With Thermal Runaway Relief
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional tool battery packs face inefficiencies in production due to curing times of waterproof materials and increased thermal runaway risks with higher charging/discharging rates, leading to potential cascading thermal runaway events.
Innovation Solution
A tool battery pack design with a waterproof member featuring a convex face that allows immediate assembly post-application, providing a controlled pressure relief mechanism through a thin area that breaks under abnormal conditions, preventing impact on adjacent cells and thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional waterproofing methods are used involving applying waterproof material and allowing it to cure, then waterproof protection is achieved, but production efficiency is constrained by curing time
Solution Approach 1:
The patent replaces the chemical curing process with a mechanical compression system. A compressible waterproof member with convex portion is positioned against the battery cell end face, and through mechanical compression force, it deforms to fill gaps and create waterproof sealing immediately, eliminating the need for chemical curing time and enabling immediate subsequent assembly operations.
2Power
If higher charging/discharging rates are used to increase tool power, then power output is improved, but thermal runaway risk increases due to larger local temperature gradients
Solution Approach 1:
The patent applies preliminary protective measures by installing a compressible waterproof member with specific material properties (flame retardancy, heat resistance) before thermal runaway can occur. This member serves as a preventive barrier that can contain thermal runaway effects if they occur during high-power operation, addressing the thermal safety issue before it manifests.
Solution Approach 2:
The compressible waterproof member acts as an intermediary element between adjacent battery cells. It provides thermal insulation and physical separation, preventing direct thermal propagation from one cell to another, thus mediating the thermal interaction and reducing the risk of cascading thermal runaway during high-rate charging/discharging.
3Reliability
If a thick waterproof layer is used to ensure waterproof protection, then sealing effectiveness is improved, but pressure relief during thermal runaway is delayed
Solution Approach 1:
The waterproof member exhibits different properties in different regions: it is compressible and deformable to provide sealing, but includes a thin portion or weak section designed to break at controlled stress levels. This local variation in quality allows it to maintain waterproof sealing under normal conditions while enabling rapid pressure relief when thermal runaway occurs.
Solution Approach 2:
The compressible nature of the waterproof member provides beforehand cushioning by allowing it to deform and absorb pressure buildup gradually. However, when pressure exceeds a certain threshold during thermal runaway, the thin portion breaks, providing sudden pressure relief. This beforehand cushioning mechanism balances sealing effectiveness with safety.
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
Enhances production efficiency by eliminating waiting times for waterproof layer drying and ensures safe pressure relief, preventing secondary thermal runaway, while maintaining effective waterproof protection and compact design.
Implementation Method 1
the waterproof layer is arranged at the second end of the battery cell holder... at least part of the waterproof layer is arranged between the second end face and the battery cell holder
Implementation Method 2
the second convex face ensures that the waterproof member compresses the waterproof layer, creating a tight seal against the battery cell end face
Implementation Method 3
the waterproof layer on the battery cell end face at the exposed hole is kept thin, enabling an abnormal unit battery cell to rapidly break the thin area, thereby providing a safe pressure relief mechanism
Data Source
AI summary
Embodiments of the present application relate to the technical field of energy. A tool battery pack is provided. The tool battery pack includes: a waterproof layer, a battery cell holder, and a waterproof member, where the waterproof member is arranged at a second end of the battery cell holder and has a first end face away from the battery cell holder and a second end face closer to the battery cell holder; at least part of the waterproof layer is arranged between the second end face and the battery cell holder; and the second end face has a second convex face protruding toward an end face of a unit battery cell at an exposed hole.