Battery Cell Lyophilic Polymer Electrolyte for Short-Circuit Control
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Solution Overview
Problem
Battery cells exhibit poor use reliability and cycle performance due to the risk of electrolyte solution extrusion leading to short circuits and dendrite formation, particularly during volume changes caused by ion intercalation and deintercalation.
Innovation Solution
Incorporating a lyophilic polymer into the electrode assembly to form a condensed electrolyte by wrapping the electrolyte solution between molecular chains, reducing the free electrolyte solution and enhancing its absorption, thereby minimizing the risk of short circuits and improving conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a battery cell uses a conventional electrolyte solution without lyophilic polymer, then the electrolyte solution provides ionic conductivity, but the electrolyte solution can be extruded during volume changes causing short circuits and poor reliability
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to gel by incorporating lyophilic polymer. This parameter change transforms the electrolyte's mechanical properties, enabling it to maintain its position and prevent extrusion during battery volume changes, while still providing ionic conductivity.
Solution Approach 2:
The patent creates a composite gel electrolyte by combining lyophilic polymer with electrolyte solution. This composite material integrates the structural stability of the polymer network with the ionic conductivity of the electrolyte solution, preventing extrusion while maintaining electrical performance.
2Reliability
If a battery cell uses a conventional electrolyte solution without lyophilic polymer, then the electrolyte solution provides ionic conductivity, but dendrite formation occurs causing short circuits
Solution Approach 1:
The patent changes the electrolyte from liquid to gel state, which alters the mechanical constraints on ion transport. The gel structure provides a more uniform ion distribution and reduces localized current density, thereby suppressing dendrite formation during charging cycles.
Solution Approach 2:
The lyophilic polymer acts as an intermediary between the electrodes and the electrolyte solution. The polymer network structure mediates ion transport, providing a more controlled and uniform pathway that prevents direct contact between electrolyte and electrode surfaces, thus reducing dendrite formation.
3Reliability
If a battery cell absorbs more free electrolyte solution into condensed electrolyte, then conductivity is improved, but the amount of free electrolyte solution available for ion transport may be reduced
Solution Approach 1:
The patent optimizes the polymer-to-electrolyte ratio to achieve the right balance between gel structure formation and free electrolyte availability. By controlling this parameter, the gel electrolyte maintains sufficient ionic conductivity while providing the structural benefits of the polymer network.
Solution Approach 2:
The patent creates different regions within the electrolyte system: the gel network regions provide structural stability and prevent extrusion, while the free electrolyte regions maintain ionic conductivity. This local differentiation of properties allows the system to simultaneously achieve reliability and electrical performance.
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 lyophilic polymer enhances the battery cell's reliability and cycle performance by locking the electrolyte solution, reducing the risk of short circuits and maintaining high conductivity.
Implementation Method 1
the electrolyte solution can be rapidly diffused between molecular chains of the lyophilic polymer, and be wrapped by the molecular chains, after swelling and adsorption, an elastic porous slow-release electrolyte is obtained
Implementation Method 2
after swelling and adsorption, an elastic porous slow-release electrolyte is obtained
Implementation Method 3
the electrolyte solution can be rapidly diffused between molecular chains of the lyophilic polymer
Data Source
AI summary
A battery cell, a battery, and an electric apparatus are disclosed. The battery cell includes an electrode assembly and an electrolyte. The electrode assembly comprises a first electrode plate, a second electrode plate, and a separator. The first and second electrode plates have opposite polarities, and the separator is arranged between them. At least one of the first electrode plate, second electrode plate, and separator includes a lyophilic polymer. The battery cell satisfies the following relationship:0.01%≤y(p1*v1+p2*v2+p3*v3)≤23%,where p1, p2, and p3 represent the porosity of the first electrode plate, second electrode plate, and separator, respectively; v1, v2, and v3 represent their respective total volumes (in μm3); and y represents the mass (in g) of free electrolyte in the battery cell. This configuration helps improve electrolyte retention and enhances the performance of the battery cell.