Battery Pack Ventilation and Pole Sealing for Hand Tools

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Solution Overview

Problem

Air-cooled battery packs for hand tools face issues with metallic dust and water ingress through ventilation openings, leading to short circuits and corrosion, while sealed packs lack effective cooling, resulting in overheating and reduced performance.

Innovation Solution

A battery pack design with a cell carrier having airtight side walls and pressure equalization devices, where battery cells are kept at a distance to prevent dust and moisture from reaching the poles, and ventilation cutouts allow cooling air to flow around the lateral surface, ensuring efficient cooling without exposing the poles to environmental contaminants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If ventilation openings are provided for air cooling, then cooling efficiency is improved, but dust and water ingress increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoiddust and water ingress
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The battery pack is divided into two functional zones: a non-hermetic cooling zone with ventilation openings for air flow, and a hermetic sealed zone protecting the battery cells. This segmentation allows each zone to perform its specific function without compromising the other - the cooling zone provides thermal management while the sealed zone prevents contaminant ingress to the cells

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A hermetic seal acts as an intermediary barrier between the ventilation openings and the battery cells. The seal allows the system to have both ventilation openings for cooling and protection against dust and water ingress by mediating between the external environment and the battery cells

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If battery cells are arranged at a distance to prevent short circuits, then reliability is improved, but cooling efficiency decreases

Engineering Contradiction:
Improveshort circuit preventionVSAvoidcooling efficiency
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The battery pack structure segments the protection function (preventing short circuits through spacing) from the cooling function (providing thermal management). The hermetic seal and housing design allow cells to be spaced apart for reliability while maintaining effective cooling pathways around each cell

Inventive Principle:
Principle #1Segmentation

3Temperature

If battery cells are completely surrounded by cooling air, then cooling efficiency is improved, but exposure to contaminants increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidcontaminant exposure
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent segments the cooling function from the protection function by creating a hermetic seal around the battery cells. The cooling air flows in the external housing and transfers heat through the cell carriers and housing walls, rather than directly surrounding the cells, thus providing cooling while preventing contaminant exposure

Inventive Principle:
Principle #1Segmentation

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 short circuits and corrosion while maintaining efficient cooling, extending the battery pack's service life and performance by isolating the poles from environmental particles and ensuring pressure equalization to prevent damage from gas emission.

Implementation Method 1

ventilation cutouts through which cooling air from the environment can penetrate into the interior of the housing and be released back into the environment, and a cell carrier for storing the at least one battery cell inside the housing... the battery cells are kept at a distance from one another and in the area of their lateral surface are separated from one another by the closed side walls... Cooling air can flow around inside the housing

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

The cell carrier also has at least two pressure equalization devices which, in the event of a predetermined overpressure at one of the pole areas of the battery pack, enable pressure equalization, in particular with the interior of the housing and with the environment via the ventilation openings of the housing

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Data Source

PatentEP3389116B1Battery pack and hand-held power tool
Publication Date: 2020.07.15 METABOWERKE
  • EP3389116B1 patent drawingFigure 1~2
  • EP3389116B1 patent drawingFigure 3~4
  • EP3389116B1 patent drawingFigure 5A~5B

AI summary

The invention relates to a battery pack (10), in particular for a power tool, comprising at least one battery cell (20) and/or a battery cell block and a housing for receiving the at least one battery cell (20), wherein the housing has ventilation recesses (18a, 18b) through which cooling air from the environment can enter the interior of the housing and be released back into the environment, and a cell carrier (12) for mounting the at least one battery cell (20) inside the housing, wherein the at least one battery cell (20) is arranged in the cell carrier (12) such that it can be exposed to the cooling air flowing around it, at least partially, in the area of ​​its outer surface. The battery cell (20) is mounted in the cell carrier (12) in such a way that the resulting terminal areas (P1, P2) of the battery pack (20) are enclosed airtight within the housing.