Lithium-Ion Battery Separator Adhesion via Neutralization
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Solution Overview
Problem
Current lithium-ion battery separators face issues with poor adhesion between the heat-resistant layer and the substrate, leading to particles easily falling off, which affects the battery's high-temperature stability and ion conductivity, causing potential short circuits and performance inconsistencies.
Innovation Solution
A separator design featuring a substrate with a base polymer and a first inorganic material, combined with a coating containing a second inorganic material, where both polymers have acid radicals in their side chains, allowing for a middle layer to be formed through hot-pressing, enhancing adhesion and preventing particle detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a ceramic heat resistant layer is coated on a porous flexible substrate to improve thermo-stability and safety, then the separator's high-temperature resistance is improved, but the adhesion between the heat resistant layer and substrate deteriorates, causing particles to fall off easily
Solution Approach 1:
The patent introduces an intermediary substance (adhesive or coupling agent) between the porous flexible substrate and the ceramic heat resistant layer to improve adhesion. This intermediary layer chemically or physically bonds to both the substrate and the ceramic particles, preventing particle detachment while maintaining the heat resistant properties of the separator.
Solution Approach 2:
The patent creates a composite structure by combining the porous flexible substrate with ceramic particles and an adhesive matrix. This composite material approach allows the separator to simultaneously achieve good adhesion (through the adhesive component) and high-temperature resistance (through the ceramic particles), resolving the contradiction between these two properties.
2Power
If the separator is made thinner to enable high power and large current density, then the power output is improved, but the risk of lithium dendrite piercing and short circuit increases
Solution Approach 1:
The patent uses a composite structure combining a thin porous flexible substrate with a ceramic heat resistant layer. The ceramic layer provides enhanced mechanical strength and puncture resistance against lithium dendrites, allowing the separator to be made thinner for high power applications without increasing short circuit risk.
Solution Approach 2:
The patent applies the ceramic heat resistant layer specifically on the surfaces of the porous substrate where it is most needed for dendrite protection. This localized enhancement of mechanical strength and heat resistance allows the bulk of the separator to remain thin for high power density, while critical areas have enhanced protection against short circuits.
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 improves the separator's thermo-stability and safety by ensuring stable ion migration and preventing particle adherence to electrodes, resulting in better battery performance and reliability.
Implementation Method 1
the first inorganic material is reactive with the first polymer via a first neutralization reaction, and the second inorganic material is reactive with the second polymer via a second neutralization reaction
Implementation Method 2
a middle layer formed between the substrate and the coating and including a part of the substrate and a part of the coating
Data Source
AI summary
A separator for a lithium-ion battery includes a substrate, a coating, and a middle layer formed between the substrate and the coating. The middle layer includes a part of the substrate and a part of the coating. The substrate contains a base polymer, a first polymer, and a first inorganic material. The coating contains a second polymer and a second inorganic material. The first polymer and the second polymer independently contain an acid radical in a side chain thereof. The first inorganic material is reactive with the first polymer via a first neutralization reaction, and the second inorganic material is reactive with the second polymer via a second neutralization reaction. A method for preparing a separator for a lithium-ion battery and a lithium-ion battery are also provided.