Secondary Battery Insulating Member for Vent Corrosion
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Solution Overview
Problem
Secondary batteries face premature vent corrosion and electrolyte leakage due to direct contact of free lithium ions with the thinnest vent wall, leading to reduced service life when a short circuit occurs between the electrode assembly and the outer casing.
Innovation Solution
Incorporating an insulating member between the electrode assembly and the vent, which extends the diffusion path for lithium ions, thereby preventing direct contact and corrosion of the vent, and ensuring the safety and longevity of the secondary battery and battery pack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If the vent wall thickness is reduced to minimize material usage and weight, then the vent becomes more susceptible to corrosion and penetration by lithium ions, but this reduces the service life and safety of the battery
Solution Approach 1:
An insulating member is introduced as an intermediary component between the electrode assembly and the vent. This insulating member extends the diffusion path for lithium ions, preventing them from directly reaching and corroding the vent. The insulating member acts as a protective barrier that mediates the interaction between the electrode assembly and the vent, solving the contradiction by maintaining vent thickness while preventing corrosion.
2Ease of operation
If the vent is positioned to facilitate electrolyte circulation and pressure release, then the vent may be in direct contact with free lithium ions during short circuit conditions, but this causes premature corrosion and electrolyte leakage
Solution Approach 1:
The insulating member serves as a protective intermediary that allows the vent to maintain its pressure release function while preventing direct contact with corrosive lithium ions. The insulating member is positioned to cover the projection of the vent on the electrode assembly, creating a barrier that protects the vent during short circuit conditions while still allowing normal pressure release operations.
Solution Approach 2:
The insulating member provides preliminary protection by preventing lithium ions from reaching the vent before corrosion can occur. By extending the diffusion path in advance, the insulating member counteracts the harmful corrosion effect before it can compromise the vent's integrity or pressure release function.
3Ease of manufacture
If no insulating member is used to simplify the battery structure, then the manufacturing process is simpler and cost is reduced, but the vent corrodes through quickly causing leakage and shortening service life
Solution Approach 1:
The insulating member is a simple component that can be easily integrated into the existing battery manufacturing process. It serves as an effective intermediary that extends the service life of the vent by preventing corrosion, with minimal impact on manufacturing complexity. The insulating member can be positioned and secured using standard manufacturing techniques.
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 insulating member effectively prolongs the time required for vent corrosion, thereby extending the service life of the secondary battery and battery pack by redirecting lithium ion diffusion along its periphery, preventing premature leakage.
Implementation Method 1
the insulating member is at least partially disposed between the electrode assembly and the vent, wherein a projection of the vent on the main body is at least partially covered by the insulating member... extend a path length for free lithium ions inside an electrode assembly to diffuse to a vent
Data Source
AI summary
The present disclosure relates to a secondary battery and a battery pack, and the secondary battery includes: an outer casing, comprising a case and a cap assembly connected to each other, the case is provided with an opening, the cap assembly includes a cap plate and an electrode terminal connected to the cap plate, wherein the cap plate is adapted to cover the opening; an electrode assembly accommodated in the case and including a main body and a tab extending out from the main body, wherein the tab is electrically connected to the electrode terminal; a vent connected to the outer casing; and an insulating member at least partially disposed between the electrode assembly and the vent, wherein a projection of the vent on the main body is at least partially covered by the insulating member.