Flexible Battery Electrode Friction Layer Design
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Solution Overview
Problem
Lithium-ion secondary batteries with stacked positive and negative electrodes tend to deteriorate in capacity and cycle characteristics when curved or bent, due to increased stress and friction, which can lead to damage and reduced performance.
Innovation Solution
The development of a power storage device with a novel electrode structure that includes a current collector, an active material layer, and a friction layer, where the friction layer has a lower coefficient of static friction than the current collector, allowing for reduced friction forces during bending and curvature, thus protecting the electrodes and maintaining battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple positive and negative electrodes are stacked to increase capacity, then the battery capacity increases, but the friction and stress during bending increase, leading to deterioration of cycle characteristics
Solution Approach 1:
A friction layer is introduced as an intermediary component between the current collector and the external environment. This friction layer has a coefficient of static friction of 0.5 or less, which is lower than that of conventional current collectors, thereby reducing the friction force during bending operations and protecting the electrode structure from damage while maintaining high capacity
Solution Approach 2:
The invention changes the friction parameter by applying a coating layer with specific low-friction properties to the current collector. This parameter change (reducing the coefficient of static friction to 0.5 or less) directly addresses the problem of electrode damage during bending, allowing the stacked electrode structure to maintain both high capacity and good cycle characteristics
2Adaptability or versatility
If the battery is curved or bent to achieve flexibility, then the battery can be used in wearable devices, but the friction force increases and causes damage to the electrodes
Solution Approach 1:
The friction layer serves as a protective intermediary that reduces the harmful friction force generated during bending. By having a coefficient of static friction of 0.5 or less, this layer minimizes the stress on the electrode structure during curvature, enabling the battery to maintain both flexibility and structural integrity
Solution Approach 2:
The invention converts the potentially harmful friction force into a beneficial low-friction interface. By deliberately designing a friction layer with extremely low friction characteristics, the harmful effect of bending-induced friction is transformed into a protective mechanism that actually reduces stress on the electrode while enabling flexibility
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 solution effectively prevents damage to the electrodes and maintains the capacity and cycle characteristics of the battery even when curved or bent, by reducing friction forces and stress, ensuring the battery's performance and longevity.
Implementation Method 1
friction force acting on the surface of the friction layer is preferably smaller than friction force acting on the surface of the current collector
Data Source
AI summary
A flexible power storage device or a power storage device of which the capacity and cycle characteristics do not easily deteriorate even when the power storage device is curved is provided. An electrode in which an active material layer, a current collector, and a friction layer are stacked in this order is provided. Furthermore, a power storage device that includes the electrode as at least one of a positive electrode and a negative electrode is provided.