Battery Pack Cooling via Side Surface Airflow Openings

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Solution Overview

Problem

Battery packs used in power tools and outdoor equipment face challenges in quickly cooling battery cells, especially when in operation, leading to increased temperature and potential performance degradation.

Innovation Solution

The battery pack design incorporates specific side surface openings that allow outside air to flow in and rise within the outer case, effectively cooling the battery cells, even when mounted on a power tool or outdoor equipment, by positioning these openings to face the longitudinal end surfaces of the battery cells, thereby enhancing heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If openings are provided in the outer case for cooling, then heat dissipation performance is improved, but structural strength is worsened

Engineering Contradiction:
Improvecooling performanceVSAvoidstructural strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The patent applies local quality by providing openings only at specific locations (side surfaces facing battery cell end surfaces) rather than uniformly across the entire outer case. This localized approach allows cooling air to flow directly over the battery cells where heat generation occurs, while maintaining structural integrity in other critical areas of the case.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs asymmetry by positioning openings asymmetrically on the outer case - specifically on side surfaces that face the longitudinal end surfaces of battery cells. This asymmetric configuration optimizes the cooling airflow path to directly target the heat-generating battery cells, rather than using a symmetric design that would be less efficient for the specific thermal management needs.

Inventive Principle:
Principle #4Asymmetry

2Temperature

If opening width is increased for better cooling, then heat dissipation is improved, but resistance to deformation is worsened

Engineering Contradiction:
Improveheat dissipationVSAvoidresistance to deformation
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent applies local quality by carefully controlling the opening width at specific locations where cooling is most needed. The openings are sized to provide adequate cooling airflow while maintaining sufficient material around the openings to resist deformation, creating an optimal balance between thermal management and structural reliability at each local position.

Inventive Principle:
Principle #3Local quality

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 configuration enables rapid cooling of battery cells, improving their performance and longevity by effectively managing heat buildup during operation, while also enhancing the structural integrity of the battery pack by reducing the width of openings at corner portions, thus minimizing the likelihood of deformation.

Implementation Method 1

outside air flows via the opening(s) into the outer case and rises within the outer case while cooling the battery cell(s)

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3799193A1Battery pack
Publication Date: 2021.03.31 MAKITA CORP
  • EP3799193A1 patent drawingFigure 1A
  • EP3799193A1 patent drawingFigure 1B
  • EP3799193A1 patent drawingFigure 1C

AI summary

Object To provide a technique in which one or more battery cells inside a battery pack can be quickly cooled. Solution A battery pack (2; 602) includes: an outer case (12; 612); one or more battery cells (90a-90j); and a cell case (80), which is housed in the outer case (12; 612) and houses the battery cell(s) (90a-90j). The outer case (12; 612) has: an upper surface (wall) (14b), in which a terminal-opening part (22a) for exposing a terminal (102) is provided; a bottom wall (15e); and a plurality of side surfaces (walls) (15a-15d) extending upward from the bottom wall (15e). The battery cell(s) (90a-90j) is (are) disposed parallel to the bottom wall (15e). An opening (40a-40j) is provided in a specific side surface (15b, 15d), from among the plurality of side surfaces (15a-15d), that faces an end surface of the battery cell(s) (90a-90j) in a longitudinal direction.