Dry Electrode Secondary Battery for Uniform Coating and Fast Charging
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Solution Overview
Problem
Conventional secondary battery manufacturing processes result in uneven material distribution and surface defects due to solvent evaporation and migration, leading to decreased adhesion and lifespan limitations.
Innovation Solution
A secondary battery design utilizing dry electrodes prepared without solvent drying, featuring a positive electrode with a fiberized binder and a negative electrode with granules, ensuring balanced electrochemical reactions and improved lifespan characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a solvent drying process is used in electrode manufacturing, then the slurry can be coated and formed into an electrode, but uneven material distribution and surface defects occur due to solvent evaporation rate differences and binder migration
Solution Approach 1:
The patent removes the solvent drying process entirely from the electrode manufacturing process. By using a dry coating method where the binder directly binds electrode materials without solvent, it extracts the harmful drying step that causes uneven evaporation and material distribution, thereby solving the contradiction between ease of manufacture and manufacturing precision
Solution Approach 2:
The patent changes the physical state parameter of the coating process from wet (solvent-based) to dry. By using a dry coating method with fiberized binder that directly binds materials, it alters the fundamental parameter of the coating process, eliminating solvent evaporation issues while maintaining manufacturability
2Ease of manufacture
If conventional wet electrodes are used, then the electrode can be manufactured with standard processes, but adhesion to current collector decreases and lifespan is limited
Solution Approach 1:
The patent uses a composite binder structure consisting of fiberized binder components that create a network architecture. This composite material approach, where the binder itself forms a fibrous network, enhances adhesion to the current collector and improves electrode structural integrity, thereby increasing reliability and lifespan while maintaining manufacturability
Solution Approach 2:
The patent employs granules with a binder network structure where the binder forms a curved, interconnected matrix around electrode materials. This curved network structure provides better mechanical interlocking and adhesion compared to flat or linear binder arrangements, improving both adhesion and lifespan
3Speed
If rapid charging is implemented, then energy delivery speed increases, but voltage stability decreases and lifespan deteriorates
Solution Approach 1:
The patent creates a porous structure through the fiberized binder network that allows rapid electrolyte penetration and ion transport. This porous architecture enables fast charging by facilitating quick ion movement while maintaining voltage stability through uniform current distribution, thus improving both speed and reliability simultaneously
Solution Approach 2:
The patent creates local quality variations through the fiberized binder network, where different regions of the electrode have optimized properties for their specific functions. The binder network provides localized adhesion zones, ion transport channels, and mechanical support, enabling the electrode to handle rapid charging while maintaining overall voltage stability and lifespan
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 secondary battery exhibits low initial resistance, fast charging capabilities, and enhanced lifespan due to the use of fiberized binders and granules in the positive and negative electrodes, respectively.
Implementation Method 1
the positive electrode binder is fiberized and binds the positive electrode active material and the positive electrode conductive material
Implementation Method 2
the plurality of granules are formed as the negative electrode binder binds the negative electrode active material
Data Source
AI summary
Provided is a secondary battery including: a positive electrode including a positive electrode current collector and a positive electrode active material layer located on the positive electrode current collector and including a positive electrode active material, a positive electrode conductive material and a positive electrode binder, wherein the positive electrode binder is fiberized and binds the positive electrode active material and the positive electrode conductive material; a negative electrode including a negative electrode current collector and a negative electrode active material layer located on the negative electrode current collector and including a plurality of granules including a negative electrode active material and a negative electrode binder, and formed as the negative electrode binder binds the negative electrode active material; and a separator disposed between the positive electrode and the negative electrode.