Lithium-Ion Battery Electrode Binder with Heat-Expandable Microcapsules
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Solution Overview
Problem
Existing lithium ion secondary battery technologies face inefficiencies in preventing temperature increases during abnormal overheating due to high internal resistance, particularly in the use of heat expandable microcapsules that require additional materials and processes, such as special current collectors and binders.
Innovation Solution
A binder composition with particles formed by a second component located on the outside of a first component, where the first component is partially exposed, utilizing a polyolefin with a specific molecular weight range and an acrylic-based polymer, providing an initial adhesive force and storage elastic modulus suitable for reducing internal resistance during overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat expandable microcapsules are used to prevent temperature increase during abnormal overheating, then safety is improved, but device complexity and material requirements increase
Solution Approach 1:
The patent combines the heat expandable microcapsule function directly into the binder composition used in electrode active material layers, merging the safety function with the existing electrode structure rather than requiring separate safety components
Solution Approach 2:
The binder composition serves multiple functions: it binds electrode active material particles together, provides structural integrity to the electrode, and incorporates heat expandable microcapsules for thermal safety, making the binder a multi-functional component
2Reliability
If heat expandable microcapsules are dispersed in electrode active material layer, then safety is improved, but manufacturing complexity increases due to additional binder requirements
Solution Approach 1:
The patent merges the heat expandable microcapsule dispersion step with the existing binder preparation process, so that microcapsules are incorporated into the binder composition during its formulation rather than requiring a separate dispersion工序
Solution Approach 2:
The binder composition simultaneously performs binding, structural support, and thermal safety functions through the integrated heat expandable microcapsules, eliminating the need for separate safety additive steps in manufacturing
3Reliability
If sufficient outside material is used to completely cover inside material in heat expandable microcapsules, then encapsulation integrity is improved, but material usage efficiency decreases
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the shell material is concentrated at the interface and surface regions where encapsulation is most needed, rather than uniformly distributing material throughout the entire microcapsule volume
Solution Approach 2:
The patent uses composite materials by combining the shell material with heat expandable core material in a core-shell structure, achieving effective encapsulation with optimized material distribution where each component performs its specific function
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 electrode effectively prevents temperature increases by increasing internal resistance during abnormal overheating, maintaining binding capacity and stability, and reducing the need for additional materials like special current collectors and binders.
Implementation Method 1
the first component contains a polyolefin with a number-average molecular weight of at least 5,000 and no greater than 15,000... a melting point of the first component is at least 60°C and no higher than 160°C
Implementation Method 2
an initial adhesive force of the binder composition is at least 1... the second component includes an acrylic-based polymer
Data Source
AI summary
It is an object of the present disclosure to provide an electrode for lithium ion secondary battery-use that can efficiently prevent a temperature increase by reducing current through an increase in the battery internal resistance during abnormal overheating. The electrode for lithium ion secondary battery-use of the present disclosure comprises a binder composition containing particles formed by a second component being located substantially on a portion of the outside of particles comprising a first component. The initial adhesive force of the binder composition is at least 1. The storage elastic modulus of the binder composition at 150°C is no greater than 1,000 Pa.