Power Tool Battery Pack Structure for Sealed Pressure Equalization
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Solution Overview
Problem
Existing battery packs for power tools face issues with air pressure imbalance due to temperature changes, leading to cell deformation and housing deformation, which affects the product's appearance and increases costs.
Innovation Solution
Incorporating deformation elements made of reversible materials with air cavities and an air-permeable device to balance internal and external air pressure, allowing for thermal expansion and improved heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cell units are sealed with sealant to meet dustproof and waterproof requirements, then sealing performance is improved, but air pressure imbalance occurs during temperature changes causing cell and housing deformation
Solution Approach 1:
The patent introduces air permeable members (porous membranes or porous plugs) within the sealed housing to allow air pressure equalization between the upper and lower cavities. These porous materials enable gas permeability while maintaining the sealed structure's dustproof and waterproof properties, preventing deformation during temperature changes.
Solution Approach 2:
The air permeable members act as intermediaries between the upper and lower sealed cavities, allowing pressure equalization without compromising the external seal. This mediator enables the sealed structure to accommodate pressure changes while maintaining its protective function.
2Shape
If air permeable members are added to balance internal and external air pressure, then deformation is prevented, but device complexity increases
Solution Approach 1:
The air permeable members are integrated into the existing sealing structure, combining the sealing function with the pressure equalization function. The porous membranes are incorporated within the sealant layers, and porous plugs are installed in connection holes during assembly, merging multiple functions into unified components.
Solution Approach 2:
The use of porous materials provides both sealing and pressure equalization functions through a single component type, reducing the need for separate air vents or complex pressure relief mechanisms while maintaining structural integrity.
3Object-affected harmful factors
If sealant is used to seal cell units, then dustproof and waterproof performance is improved, but manufacturing precision requirements increase due to deformation risks
Solution Approach 1:
The porous membranes and plugs provide built-in pressure equalization within the sealed structure, eliminating the need for precise control of sealant thickness or air gaps. The pressure equalization occurs automatically through the porous materials, reducing sensitivity to assembly variations.
Solution Approach 2:
The air permeable members serve as intermediaries that decouple the sealing quality from pressure balance requirements, allowing sealant application without precise thickness control while still achieving both dustproof/waterproof performance and pressure equalization.
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
Maintains structural integrity and reduces costs by preventing cell and housing deformation while ensuring safety and ease of assembly.
Implementation Method 1
When the battery pack is stored at high temperatures or in the process of charging and discharging, the air pressure in the sealed space increases as the temperature rises
Implementation Method 2
a deformation assembly comprising a deformation element and a support element, the deformation element being arranged between the cell assembly and the support element in a direction parallel to a stacking direction of the cell units, the deformation element being deformable along an axis parallel to the stacking direction of the cell units
Implementation Method 3
at least one air-permeable passage is formed on the air-permeable device, the air-permeable passage connecting with multiple air cavities and connects with air outside the sealed chamber
Data Source
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AI summary
Provided are a battery pack and a power tool. The battery pack includes a housing; a cell assembly including multiple stacked cell units; elastic pads separately disposed between adjacent ones of the multiple cell units, where air cavities are formed between the elastic pads and the adjacent ones of the multiple cell units; a sealing member disposed at least on the surface of the cell assembly, where the sealing member and the housing form a sealed chamber; and an air-permeable element partially disposed on the side surface of the cell assembly and extending into multiple air cavities along the first direction, where the air-permeable element connects with the air outside the sealed chamber.