Battery Pack Cooling Draft Division for Uniform Cell Temperature

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Solution Overview

Problem

Existing battery packs with longitudinally arranged battery cells experience cooling unevenness during charging, leading to reduced charging efficiency and increased risk of overheating due to inadequate cooling distribution, necessitating lower charging currents and longer charging times.

Innovation Solution

The battery pack design incorporates longitudinal-direction passageways and a branch part within the case to ensure even cooling by directing cooling drafts along the longitudinal direction of all battery cells, with a cell holder and partitioning ribs to enhance cooling efficiency and prevent rattling, while maintaining compactness and protecting the cells from moisture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If battery cells are arranged longitudinally in parallel to minimize space, then the battery pack achieves compactness and space efficiency, but cooling unevenness occurs during charging leading to reduced charging efficiency

Engineering Contradiction:
Improvebattery pack volumeVSAvoidcooling uniformity
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The case is divided into multiple cooling chambers by partitioning ribs, with each chamber containing one or more battery cells. This segmentation ensures that cooling drafts can be distributed evenly to each battery cell through dedicated cooling passages, preventing cooling unevenness while maintaining the compact longitudinal arrangement of cells.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the case are provided with localized cooling passages and partitioning ribs that direct cooling drafts specifically to each battery cell's position. The ventilation path is designed to deliver cooling air to specific locations where battery cells are housed, ensuring uniform cooling across all cells without requiring a larger pack volume.

Inventive Principle:
Principle #3Local quality

2Productivity

If cooling drafts are supplied to longitudinally arranged battery cells, then space is minimized, but only cells that guide the flow are cooled evenly while others experience insufficient cooling

Engineering Contradiction:
Improvecharging speedVSAvoidbattery cell temperature distribution
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The ventilation path is segmented into multiple cooling passages separated by partitioning ribs. Each passage is designed to direct cooling drafts to specific battery cells, ensuring that all cells receive adequate cooling regardless of their position in the longitudinal arrangement. This enables higher charging currents to be applied safely.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Partitioning ribs act as intermediaries that guide and distribute cooling drafts from the ventilation mechanism to each battery cell. These ribs create dedicated cooling passages that ensure even distribution of cooling air to all longitudinally arranged cells, preventing temperature hotspots that would limit charging speed.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If ventilation mechanism delivers forced cooling air into the case interior, then cooling effect is improved, but cooling draft flows parallel to mounting direction causing uneven cooling of parallel-disposed battery cells

Engineering Contradiction:
Improvebattery cell cooling effectivenessVSAvoidcooling uniformity across cells
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The ventilation path is designed with localized cooling passages that direct cooling drafts to each specific battery cell position. Partitioning ribs create dedicated channels that ensure cooling air reaches each cell uniformly, transforming the general forced cooling into targeted local cooling that maintains precision and uniformity across all cells.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of allowing cooling drafts to flow only parallel to the mounting direction (one dimension), the partitioning ribs create three-dimensional cooling passages that distribute cooling air in multiple directions to reach all battery cells. This dimensional expansion of the cooling path ensures uniform cooling despite the longitudinal cell arrangement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 achieves uniform cooling of battery cells, allowing for higher charging currents and reduced charging times without risking overheating, while maintaining compactness and preventing short circuits.

Implementation Method 1

a ventilation path is provided in the interior of the case and makes possible ventilation of the battery cells, wherein the first ventilation hole serves as an inlet of the ventilation path and the second ventilation holes serve as outlets of the ventilation path. A plurality of longitudinal-direction passageways, wherethrough cooling drafts respectively flow along the longitudinal direction of the battery cells, is provided in the ventilation path

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3059782B1Battery pack
Publication Date: 2018.04.04 MAKITA CORP
  • EP3059782B1 patent drawingFigure 1
  • EP3059782B1 patent drawingFigure 2
  • EP3059782B1 patent drawingFigure 3

AI summary

As a cooling draft flows from a rear side to a front side of battery cells (72) inside a battery pack (30), it is divided into two cooling drafts (F1, F2) in a left-right direction, which is the direction that the battery cells (72) are disposed in parallel, and those two cooling drafts respectively flow through a plurality of passageways that longitudinally extend along the battery cells (72). More particularly, a second battery cell (722) is cooled by the cooling draft flowing in a second ventilation-path volume (Q2) before a first battery cell (721) and a third battery cell (723) are cooled by cooling drafts respectively flowing in a first ventilation-path volume (Q1) and a third ventilation-path volume (Q3), which are longer than the second ventilation-path volume (Q2).