Sealed Battery Valve Body Coating for Electrolyte Corrosion Resistance

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Solution Overview

Problem

In the manufacturing of sealed batteries, electrolyte solution overflow and scattering can lead to corrosion of the valve body, resulting in decreased valve operating pressure and sealability due to the electrolyte solution adhering to the valve body, especially when the battery case is sealed.

Innovation Solution

A sealed battery design where the valve body is covered with a protective layer having corrosion resistance, and the valve body is fixed to the bottom plate using a folded portion of the bottom plate, preventing direct contact of the electrolyte solution with the valve body's end surface, thus preventing corrosion and maintaining sealability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the valve body is made exposed for easy manufacturing, then manufacturing precision is improved, but the valve body becomes susceptible to electrolyte solution corrosion

Engineering Contradiction:

Improvevalve body exposureVSAvoidelectrolyte solution corrosion

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies a resin coating film on the valve body surface to protect it from electrolyte solution corrosion. This thin film barrier prevents direct contact between the corrosive electrolyte and the valve body metal, solving the contradiction between manufacturing ease and corrosion resistance.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The valve body is constructed as a composite structure with a metal base layer providing mechanical strength and a resin coating layer providing corrosion resistance. This composite approach allows the valve body to maintain manufacturing simplicity while gaining protection against electrolyte solution.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the valve body is fully covered with resin material, then corrosion resistance is improved, but valve operating pressure decreases due to reduced metal surface area

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidvalve operating pressure

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The resin coating is applied selectively to specific areas of the valve body surface rather than complete coverage. This local protection approach maintains corrosion resistance at critical surfaces while preserving sufficient metal surface area to maintain valve operating pressure and mechanical performance.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20230268594A1Hermetically sealed battery

Publication Date: 2023.08.24 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A sealed battery includes a battery case with a bottomed cylindrical shape having an opening; an electrode body housed in the battery case; an electrolyte solution; and a sealing member that closes the opening of the battery case. The sealing member is formed by stacking a terminal cap, a bottom plate electrically connecting the terminal cap and an electrode of one polarity of the electrode body, and a valve body interposed between the terminal cap and the bottom plate. The valve body has a surface covered with a resin material, and an end surface that is an outer edge of the valve body is covered with a protective layer containing a compound A having corrosion resistance to the electrolyte solution.