Battery Lid Insulation Layer for Seawater Short-Circuit Prevention
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Solution Overview
Problem
Lithium ion secondary batteries exposed to sea water or salt water experience electrical short-circuits due to the formation of conductive red rust between the battery can and the terminal plate, leading to a decrease in battery voltage and functionality.
Innovation Solution
Incorporating a metal layer made of aluminum between the battery lid and the gasket to maintain electrical insulation, preventing the formation of conductive oxides or hydroxides that could cause short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional battery sealing structure is used, then the battery can be hermetically sealed, but red rust precipitates between the battery can and terminal plate when exposed to sea water, causing electrical short-circuit
Solution Approach 1:
An aluminum layer is introduced as an intermediary between the battery can and the gasket. This aluminum layer acts as a sacrificial anode that preferentially reacts with salt water to form insulating aluminum oxides or hydroxides, preventing the formation of conductive red rust between the battery can and terminal plate, thus maintaining electrical insulation.
Solution Approach 2:
The invention converts the harmful effect of salt water exposure into a beneficial protective mechanism. The aluminum layer is deliberately designed to react with salt water first, forming insulating oxide/hydroxide layers that protect the underlying battery components. The harmful salt water exposure triggers a protective reaction that prevents electrical short-circuiting.
2Reliability
If the battery is exposed to salt water, then the aluminum layer dissolves preferentially forming insulating oxides or hydroxides, but this requires additional material layer increasing device complexity
Solution Approach 1:
The battery sealing structure is designed as a composite system comprising the battery can, the gasket, and an aluminum layer positioned between them. This composite structure combines materials with different properties: the aluminum layer provides sacrificial protection and forms insulating oxides, while the underlying battery can provides structural support. The composite design enables the system to maintain electrical insulation without significantly increasing overall complexity.
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 aluminum layer preferentially dissolves in salt water, forming insulating oxides or hydroxides, thereby maintaining electrical insulation and preventing short-circuits, ensuring the battery's functionality even when exposed to aqueous solutions with ion conductivity.
Implementation Method 1
the aluminum layer preferentially dissolves in salt water, forming insulating oxides or hydroxides
Implementation Method 2
forming insulating oxides or hydroxides
Data Source
AI summary
Provided is a battery capable of maintaining electrical insulation between a battery lid and a battery can when exposed to an aqueous solution such as sea water.Disclosed is a secondary battery including an electrode winding body in which a strip-shaped positive electrode and a strip-shaped negative electrode are stacked with a separator interposed between the electrodes and wound, an electrolytic solution, and a battery can that houses the electrode winding body and the electrolytic solution, the battery can having an opening hermetically sealed by a safety valve mechanism and a battery lid with a gasket interposed therebetween, in which the battery lid includes a terminal portion and a flange portion, and a metal layer is included between an outer main surface of among main surfaces of the flange portion and the gasket.