Stacked Battery Electrode Basis Weight for Uniform Degradation
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Solution Overview
Problem
In assembled batteries, electrodes at lower positions in the stacking direction experience thinning due to the load of upper electrodes, leading to increased capacity and variations in electrode degradation due to overcharging.
Innovation Solution
The battery design includes electrodes with a larger basis weight and density of negative- or positive-electrode composite materials at upper positions compared to lower positions, which helps to reduce capacity variations and electrode degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electrodes are stacked in the stacking direction to increase battery capacity, then the battery capacity increases, but the electrodes at lower positions are thinned by the load of upper electrodes, causing variations in state of charge and electrode degradation
Solution Approach 1:
The patent applies local quality by making the basis weight of electrode active materials position-dependent within the stack. Specifically, electrodes at upper positions have a larger basis weight (mg/cm²) of negative- or positive-electrode composite materials compared to electrodes at lower positions. This spatial variation in material distribution compensates for the thinning effect caused by gravitational loading, ensuring more uniform state of charge and degradation across all electrode positions during charging operations.
2Reliability
If the basis weight of electrode materials is increased at upper positions, then the thinning effect on lower electrodes is compensated, but the manufacturing complexity increases due to position-dependent material distribution
Solution Approach 1:
The patent implements local quality by specifying that the basis weight of electrode composite materials varies by position in the stacking direction. Upper electrodes have higher basis weight than lower electrodes, creating a deliberate non-uniform material distribution that compensates for gravitational thinning effects. This approach addresses manufacturing complexity by providing a clear, position-based guideline for material application during assembly.
Data Source
AI summary
An assembled battery includes a plurality of electrodes each including; a current collector; a negative-electrode composite layer disposed on one surface of the current collector; and a positive-electrode composite layer on the other surface of the current collector, the electrodes being stacked alternately with an electrolyte layer interposed between the electrodes, and a basis weight (mg/cm2) of a negative-electrode composite material or a positive-electrode composite material in the negative-electrode composite layer or the positive-electrode composite layer of each of the electrodes located at upper positions in a stacking direction of the assembled battery is larger than a basis weight (mg/cm2) of a negative-electrode composite material or a positive-electrode composite material in the negative-electrode composite layer or the positive-electrode composite layer of each of the electrodes located at lower positions in the stacking direction of the assembled battery.