Battery Pack Waterproofing via Segmented Case and Elastic Seals

Solution Overview

Problem

Lithium ion battery packs face challenges in maintaining waterproofing while allowing for air intake to cool the battery cells, which is essential for preventing moisture-induced breakdowns.

Innovation Solution

A battery pack design featuring an exterior case with hole sections for air intake, a battery holder with elastic rubber rings that constrict around the positive electrode terminal sections, and a metal plate for terminal contact, ensuring effective waterproofing and heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sealing structure using the case is adopted to improve waterproofing properties, then waterproofing is improved, but air intake for cooling is prevented

Engineering Contradiction:

Improvewaterproofing propertiesVSAvoidbattery cell temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The sealing function is segmented from the case structure. Instead of sealing the entire case, only the battery cell insertion port is sealed using a gasket, while the case retains hole sections for air intake. This segmentation allows the case to simultaneously provide cooling airflow and waterproof protection at critical interfaces.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A gasket is introduced as an intermediary sealing element between the case and battery cell. The gasket provides waterproofing at the insertion port without requiring the case itself to be fully sealed, thereby allowing the case to maintain open hole sections for cooling purposes.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the case is fully sealed to prevent moisture entry, then waterproofing is improved, but heat dissipation is reduced

Engineering Contradiction:

Improvewaterproofing propertiesVSAvoidheat dissipation efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The sealing function is segmented from the case structure. Instead of sealing the entire case, only the battery cell insertion port is sealed using a gasket, while the case retains hole sections for air intake. This segmentation allows the case to simultaneously provide cooling airflow and waterproof protection at critical interfaces.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Waterproofing is applied locally only where needed (at the battery cell insertion port using a gasket) rather than sealing the entire case. This local quality approach maintains waterproofing at critical interfaces while leaving the case body open for heat dissipation and cooling airflow.

Inventive Principle:

Principle #3Local quality

3Temperature

If hole sections are provided in the case for air intake, then cooling is improved, but moisture ingress risk increases

Engineering Contradiction:

Improvebattery cell temperatureVSAvoidmoisture ingress

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The sealing function is extracted from the case and assigned to a separate gasket component. This allows the case to have open hole sections for cooling without compromising waterproofing, as the gasket provides the sealing barrier at the battery cell interface.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Waterproofing is applied locally only where needed (at the battery cell insertion port using a gasket) rather than sealing the entire case. This local quality approach maintains waterproofing at critical interfaces while leaving the case body open for heat dissipation and cooling airflow.

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

The design enhances waterproofing properties while allowing for efficient air cooling of battery cells, preventing moisture ingress and maintaining performance.

Implementation Method 1

an elastic body having an opening is placed between the one end surface of the battery cell and the end section of the battery cell receiving section, a predetermined portion of the elastic body is constricted by an end surface near the positive electrode terminal section and an inner surface of the end section

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

it is desirable to provide a hole section in the case to take in air from the outside via the hole section. The battery cell can be cooled by air taken from the outside

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS9105900B2Battery pack, electricity accumulation system, electronic instrument, electric vehicle, and electric power system

Publication Date: 2015.08.11 MURATA MFG CO LTD

AI summary

Provided is a battery pack including: an exterior case formed with one or more hole sections; a battery cell in which a positive electrode terminal section is formed on one end surface thereof and a negative electrode terminal section is formed on the other end surface thereof; a battery holder having a plurality of battery cell receiving sections receiving the battery cell; and a metal plate joined to the battery holder and formed with a terminal contact section.