Electrode Tab Insulation Coating to Prevent Battery Short-Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Secondary batteries face safety issues due to internal short-circuits, particularly when the insulation member on electrode tabs degrades and detaches during thermal and mechanical abuse, leading to potential ignition.
Innovation Solution
An insulation coating layer with a binder having a controlled electrolyte uptake (between 0% and 50% or 0% and 150%) is applied to the electrode tabs, using a mixture of organic solvents like ethylene carbonate, propylene carbonate, and diethyl or propyl propionate, along with inorganic fillers like SiO2, to enhance adhesion and prevent detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulation member is attached to the electrode tab to prevent internal short-circuit, then safety is improved, but the insulation member degrades and detaches during thermal and mechanical abuse
Solution Approach 1:
The patent changes the chemical composition parameters of the binder by controlling the acrylic acid monomer content (5-20 mass%) and using specific molecular weight ranges (10,000-100,000). These parameter changes enable the binder to maintain optimal adhesion to the current collector while providing sufficient insulation properties, preventing detachment during thermal and mechanical abuse.
Solution Approach 2:
The patent creates a composite insulation coating layer combining the binder polymer with inorganic fillers (such as alumina, silica, or titania). This composite structure provides both the adhesion needed to prevent detachment and the insulation properties needed to prevent internal short-circuits, resolving the contradiction between stability and safety.
2Reliability
If the binder has high electrolyte uptake to improve insulation properties, then insulation performance is improved, but adhesion to the electrode tab deteriorates
Solution Approach 1:
The patent optimizes the electrolyte uptake parameter to a specific range (20-80 mL/g) by controlling the binder's molecular weight (10,000-100,000) and acrylic acid monomer content (5-20 mass%). This parameter optimization ensures sufficient insulation performance while maintaining strong adhesion to the current collector, preventing both internal short-circuits and detachment.
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 solution effectively minimizes internal short-circuits and ensures safety by maintaining excellent insulation and adhesion of the insulation coating layer on the electrode tabs, even under high voltage and thermal stress conditions.
Implementation Method 1
the binder has an electrolyte uptake more than 0% and less than 50%, and the electrolyte uptake is determined by the method including the steps of: preparing an electrolyte including an organic solvent containing a mixture of ethylene carbonate, propylene carbonate and diethyl carbonate, and a lithium salt; molding the binder into a film shape, cutting the film into a predetermined size, weighing the binder before dipping, dipping the film in the electrolyte at room temperature for 1 hour and removing the film from the electrolyte, and weighing the binder after dipping
Data Source
AI summary
Provided is a secondary battery which includes an electrode assembly having an electrode tab extended from an electrode current collector, wherein the electrode tab is provided with an insulation coating layer containing an inorganic filler and a binder, the binder has an electrolyte uptake more than 0% and less than 50%, and the electrolyte uptake is determined by a predetermined method. In the secondary battery according to the present disclosure, the insulation coating layer provided in the electrode tab includes a binder having a low electrolyte uptake, and thus the insulation coating layer has improved adhesion and is prevented from detachment from the electrode tab. As a result, it is possible to maintain an excellent insulation state and to minimize an internal short-circuit in a secondary battery, thereby ensuring safety.