Non-Aqueous Battery Cathode Layout for Gravity-Driven Electrolyte Imbalance
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Solution Overview
Problem
Non-aqueous electrolyte secondary batteries face challenges in maintaining optimal charge-discharge cycle characteristics due to uneven electrolyte distribution caused by gravity, leading to deteriorated performance.
Innovation Solution
The battery design incorporates a positive electrode mixture layer with varying dibutyl phthalate oil absorptions in different regions, where the upper half region has a higher dibutyl phthalate oil absorption than the lower half region, ensuring even electrolyte distribution and retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the positive electrode mixture layer uses uniform positive electrode active material throughout, then the manufacturing process is simple, but the charge-discharge cycle characteristics deteriorate due to uneven electrolyte distribution
Solution Approach 1:
The positive electrode mixture layer is designed with different positive electrode active materials having different DBP absorptions in different regions (upper half vs lower half). The upper half region contains active material with higher DBP absorption to compensate for electrolyte depletion caused by gravity, while the lower half uses material with lower DBP absorption. This local differentiation improves charge-discharge cycle characteristics without requiring complex external systems.
2Reliability
If the battery uses high DBP absorption positive electrode active material throughout, then electrolyte retention is improved, but the energy density and output performance decrease
Solution Approach 1:
Instead of uniformly using high DBP absorption material throughout the electrode, the invention applies high DBP absorption material specifically in the upper half region where electrolyte depletion occurs, while using lower DBP absorption material in the lower half region. This localized approach maintains electrolyte retention where needed while preserving energy density and output performance in regions where high DBP absorption is not required.
3Ease of manufacture
If the battery operates in fixed orientation, then manufacturing and assembly are simplified, but electrolyte distribution becomes uneven due to gravity
Solution Approach 1:
The invention designs the positive electrode mixture layer with spatially varying DBP absorption properties corresponding to different gravitational regions (upper vs lower halves). This allows the battery to maintain reliable electrolyte distribution when operated in a fixed orientation during manufacturing and assembly, while the local material differentiation compensates for gravity-induced electrolyte depletion in the upper region.
Solution Approach 2:
The invention converts the harmful effect of gravity causing electrolyte depletion in the upper region into a beneficial design parameter by selecting positive electrode active materials with appropriately higher DBP absorption for the upper half region. This transforms the gravitational harm into a controlled material property variation that improves overall battery 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
This design enhances charge-discharge cycle characteristics by maintaining electrolyte distribution and improving retention, resulting in improved battery performance.
Implementation Method 1
a dibutyl phthalate oil absorption of the positive electrode active material contained in the positive electrode mixture layer disposed in an upper half region is higher than a dibutyl phthalate oil absorption of the positive electrode active material contained in the positive electrode mixture layer disposed in a lower half region
Data Source
AI summary
A non-aqueous electrolyte secondary battery is characterized by comprising an electrode body in which a positive electrode and a negative electrode face each other with a separator therebetween, and a battery case that accommodates the electrode body, wherein: the positive electrode has a positive electrode mixture layer containing a positive electrode active material; and when the non-aqueous electrolyte secondary battery is used in a fixed state, and the electrode body in the fixed state is bisected in the vertical direction, a dibutyl phthalate oil absorption amount of the positive electrode active material contained in the positive electrode mixture layer disposed in the top half region is higher than a dibutyl phthalate oil absorption amount of the positive electrode active material contained in the positive electrode mixture layer disposed in the bottom half region.