Lithium Ion Battery Electrode Using Collapsed Hollow Resin Particles
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Solution Overview
Problem
Rechargeable lithium ion batteries face challenges in increasing active material density and electrolyte solution permeability, leading to limited capacity and rate characteristics due to buckling of electrode plates and decreased pore volume during rolling.
Innovation Solution
Incorporating hollow resin particles into the positive and negative electrode mixture layers before rolling, which collapse during the process, allowing for increased active material density and forming pores for enhanced electrolyte permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the electrode plates are rolled to increase active material density, then the capacity increases, but the electrode plates buckle due to expansion and shrinking of active material
Solution Approach 1:
The patent incorporates porous resin particles into the electrode plate structure. These particles create void spaces that accommodate the expansion and contraction of active material during charging and discharging cycles, preventing buckling while maintaining high active material density through the rolled structure.
Solution Approach 2:
The patent creates a composite structure by combining active material, binder, conductive agent, and porous resin particles into a unified electrode plate matrix. This composite approach allows the different components to work together - the resin particles provide structural flexibility while the active material maintains high density through rolling.
2Stability of the object's composition
If resin particles are incorporated in electrode plates to prevent buckling, then electrode plate stability improves, but active material density cannot be increased by rolling
Solution Approach 1:
The patent specifies using porous resin particles with a porosity of 30% or more. These porous particles create internal void spaces that can be compressed during rolling without significantly increasing the overall volume, thereby allowing high active material density to be achieved while maintaining the stability provided by the resin particle network.
Solution Approach 2:
The patent optimizes the porosity parameter of the resin particles (30% or more) and controls their content (1-20 parts by weight per 100 parts by weight of active material) to achieve the right balance between structural stability and packability during rolling, enabling both stability and high active material density.
3Quantity of substance
If hollow resin particles are used to increase active material density through rolling, then capacity increases, but electrolyte solution permeability decreases due to reduced pore volume
Solution Approach 1:
The patent uses porous resin particles that maintain their porous structure after rolling. The high porosity (30% or more) of these particles ensures that even after the electrode plate is rolled to increase active material density, sufficient pore volume remains to allow electrolyte solution penetration and maintain reliable electrochemical performance.
Solution Approach 2:
The porous resin particles are incorporated into the electrode plate before rolling. This preliminary incorporation ensures that the porous structure is established in advance, and the rolling process compresses the overall plate while the porous particles maintain their internal void spaces, preserving electrolyte permeability despite increased density.
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 method enables higher active material density and electrolyte solution permeability, thereby increasing the capacity and rate characteristics of rechargeable lithium ion batteries.
Implementation Method 1
When a scanning electron microscope image of the surface of the positive electrode mixture layer or the negative electrode mixture layer containing the resin particles is reduced to a 256 gray-scale image and then is binarized into black pixels and white pixels at a threshold of 70, a ratio of the total area of the black pixels to the total area of entire pixels is 10% or more and 20% or less.
Implementation Method 2
the mixture layer contains resin particles obtained by collapsing hollow resin particles by rolling
Implementation Method 3
the resin particles function as a lubricating agent and allow the active material to move so as to absorb the expansion thereof, thereby preventing the buckling of the electrode plate
Implementation Method 4
there is disclosed an art (refer to, for example, Japanese Patent No. 3581474) of using an active material formed in the shape of a hollow particle and filling therein an electrical conduction enhancer. By filling the electrical conduction enhancer in the active material having such a hollow structure mentioned above, the conductivity can be increased
Data Source
AI summary
The present invention relates to a rechargeable lithium ion battery having an electrode plate with a high active material density and high electrolyte permeability. Upon producing the rechargeable lithium ion battery, hollow resin particles that can be collapsed by rolling are incorporated in a positive electrode mixture layer or a negative electrode mixture layer before the electrode mixture layer is rolled. The hollow resin particles are collapsed in the course of rolling the positive electrode mixture layer or the negative electrode mixture layer, so that the active material density can be easily increased. Further, the collapsed resin particles form unevenness on the surface of the electrode plate and also form open pores in the electrode plate, so that electrolyte permeability can be enhanced. As a result, the discharge capacity and rate characteristics of rechargeable lithium ion batteries can be increased.