Negative Electrode Plate Cavities for Fast-Charging Li-Ion Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing negative electrode plates in secondary batteries suffer from poor fast charging capability and safety performance due to concentration polarization and slow liquid phase conduction of active ions, leading to potential safety risks like lithium dendrite formation and short circuits.
Innovation Solution
A negative electrode plate design featuring infiltrating cavities on the film layer, which reduces the diffusion path of ions and improves electrolyte infiltration, allowing for faster ion migration and uniform charging, thereby enhancing safety and fast charging performance. The cavities are strategically oriented and dimensioned to optimize ion transfer and electrolyte distribution within the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the negative electrode film layer is made thicker to increase capacity, then the battery capacity is improved, but the diffusion path of ions becomes longer causing concentration polarization and poor fast charging capability
Solution Approach 1:
The negative electrode film layer is segmented into multiple regions by introducing infiltrating cavities that divide the continuous film into separated zones. This segmentation creates multiple ion diffusion pathways, reducing the effective diffusion distance for ions while maintaining the overall film thickness and capacity. The cavities act as internal channels that break up the long diffusion path into shorter segments.
Solution Approach 2:
The infiltrating cavities introduce a new dimensional feature (through-holes extending through the film thickness) to the traditionally two-dimensional film structure. This third dimension provides direct ion transport channels from one side of the film to the other, bypassing the need for lateral diffusion through the entire film thickness, thus reducing concentration polarization.
2Speed
If the negative electrode film layer is made thinner to improve ion diffusion, then fast charging capability is improved, but the battery capacity decreases
Solution Approach 1:
By segmenting the film structure with infiltrating cavities, the effective diffusion distance is reduced without proportionally reducing the total active material volume. The cavities create multiple access points for ions, allowing thinner effective diffusion zones while maintaining overall film thickness and capacity through increased surface area utilization.
Solution Approach 2:
The infiltrating cavities create a porous structure within the negative electrode film layer. This porous architecture increases the surface area available for ion interaction while reducing the diffusion path length. The porosity allows electrolyte penetration throughout the film thickness, enabling fast ion transport without sacrificing active material content.
3Ease of manufacture
If conventional negative electrode plates are used to maintain simple structure, then manufacturing is easier, but safety performance deteriorates due to lithium dendrite formation and short circuits
Solution Approach 1:
The infiltrating cavities create a controlled porous structure that allows uniform electrolyte distribution throughout the negative electrode film layer. This prevents localized concentration gradients that lead to lithium dendrite formation. The porous architecture ensures consistent ion flux across the entire film, eliminating hotspots where dendrites typically initiate, thereby improving safety without complicating manufacturing.
Solution Approach 2:
The infiltrating cavities are pre-formed in the negative electrode film layer before battery assembly. This preliminary structuring ensures that electrolyte infiltration pathways are established in advance, preventing uneven ion distribution and dendrite formation from the first charge cycle. The pre-configured cavities guide uniform electrolyte penetration, proactively preventing safety issues rather than addressing them after they arise.
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 design significantly reduces concentration polarization, improves fast charging capacity, and enhances safety by ensuring uniform ion migration and reduced risk of lithium dendrite formation, leading to improved performance and safety of secondary batteries.
Implementation Method 1
the diffusion path of active ions such as lithium ions in the negative electrode plate becomes shorter
Implementation Method 2
the electrolytic solution infiltrates the electrode assembly more uniformly
Data Source
AI summary
The present application provides a negative electrode plate and the method for preparing the same, a secondary battery, and an electrical device. The negative electrode plate includes a negative electrode current collector, and a negative electrode film layer arranged on at least one surface of the negative electrode current collector, wherein the negative electrode film layer comprises infiltrating cavity which opens in a direction away from the negative electrode current collector and extend in a first direction; and wherein the negative electrode film layer has a dimension in the first direction denoted as A in μm, the infiltrating cavity has a dimension in the first direction denoted as A1 in μm, and the negative electrode plate satisfies 0.1≤A1/A≤1, and optionally, 0.2≤A1/A≤1.