Electrode Assembly Layout to Limit Ion Precipitation in Battery Cells
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Solution Overview
Problem
Current battery technologies face challenges in improving energy density and safety performance due to wastage of active materials and ion precipitation risks in electrode assemblies, particularly in laminated-type structures where the negative electrode active material layer is coated on both sides, leading to inefficiencies and complications in the manufacturing process.
Innovation Solution
The electrode assembly features a unilateral positive electrode sheet with the active material layer coated only on the inner side of the current collector, and a continuously bent negative electrode sheet with laminated segments, reducing wastage and ion precipitation risks by ensuring ions are embedded in the negative electrode active material layer, and using separators to enhance insulation and prevent short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the positive electrode active material layer is coated on both sides of the current collector, then the energy density can be improved, but the risk of ion precipitation increases and safety performance deteriorates
Solution Approach 1:
The patent applies asymmetry by coating the positive electrode active material layer only on one side of the current collector instead of both sides. This creates an asymmetric electrode structure where the coated side faces the negative electrode, allowing ions to be effectively embedded in the negative electrode active material layer while preventing ion precipitation. The asymmetric design resolves the contradiction by maintaining energy density through effective material utilization while improving safety by eliminating the risk of ion precipitation that would occur with bilateral coating.
2Quantity of substance
If the negative electrode active material layer is coated on both sides of the current collector, then the energy density can be improved, but the manufacturing complexity increases and wastage occurs
Solution Approach 1:
The patent applies the extraction principle by removing the unnecessary positive electrode active material layer from one side of the current collector. Instead of coating both sides, the solution extracts only the essential coating on one side that faces the negative electrode. This eliminates wastage of positive electrode active material and simplifies the manufacturing process while maintaining effective energy density through proper utilization of the remaining coated layer.
3Quantity of substance
If the unilateral electrode extends beyond the bent segment, then the active material utilization can be improved, but ion precipitation risk increases
Solution Approach 1:
The patent applies local quality by precisely controlling the extent of the unilateral electrode relative to the bent segment. The electrode is designed to extend to a specific location that optimizes active material utilization while preventing ion precipitation. This localized control ensures that the electrode achieves effective contact with the negative electrode for maximum active material utilization, while the precise positioning within the bent segment boundaries prevents the harmful effect of ion precipitation.
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
This configuration enhances energy density, simplifies the manufacturing process, and improves safety performance by minimizing ion precipitation and reducing the risk of short circuits, while maintaining a simple preparation process and efficient assembly.
Implementation Method 1
ions released from the positive electrode active material layer of the unilateral electrode can get embedded in the negative electrode active material layer
Data Source
AI summary
An electrode assembly may include positive and negative electrode sheets, the positive and negative electrode sheets including positive and negative electrode current collectors and positive and negative electrode active material layers. The negative electrode sheet may be continuously bent and include a plurality of laminated segments and a plurality of bent segments for connecting the laminated segments; a plurality of the positive electrode sheets may be alternately laminated with the plurality of laminated segments in a first direction. An outermost positive electrode sheet may be a unilateral electrode having the positive electrode active material layer coated on an inner side rather than outer side of the positive electrode current collector thereof. The bent segment may be connected to an end of the laminated segment in a second direction; and the unilateral electrode may not extend beyond the adjacent bent segment.