Foldable Battery Cell Structure to Reduce Folding Stress
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Solution Overview
Problem
Foldable electronic devices face challenges with battery durability due to repeated folding operations, leading to fatigue failure of the substrate in the folding area, which can result in battery malfunction.
Innovation Solution
The electronic device incorporates a battery cell with a non-overlap stacked structure in the folding area, where the substrate members forming opposite electrodes do not overlap, and a reinforcing member is added to the electrode substrate to enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the substrate members are stacked in the folding area to maintain battery capacity, then the battery capacity is improved, but the flexibility and stress resistance during folding deteriorate
Solution Approach 1:
The battery is divided into a first cell area with stacked substrate members for high capacity and a second cell area with a single substrate member for flexibility. This segmentation allows each region to serve its specific function while working together as a unified battery system.
Solution Approach 2:
Different structural configurations are applied to different regions: the first cell area uses a stacked structure optimized for capacity, while the second cell area uses a single-layer structure optimized for bending flexibility. Each local region has properties tailored to its functional requirements.
2Reliability
If the substrate members are made thicker to improve durability, then the durability is improved, but the flexibility and bending capability deteriorate
Solution Approach 1:
The battery structure is segmented into regions with different thickness characteristics. The first cell area has greater thickness for durability, while the second cell area has reduced thickness for flexibility, allowing the battery to withstand both mechanical stress and repeated folding.
Solution Approach 2:
The solution transitions from a uniform two-dimensional stacking approach to a three-dimensional configuration where substrate members are arranged in different spatial patterns in different areas, enabling simultaneous optimization of thickness for both durability and flexibility.
3Quantity of substance
If the substrate members overlap in the folding area, then the battery capacity is improved, but the stress concentration during folding increases leading to fatigue failure
Solution Approach 1:
The battery is divided into a first cell area where substrate members overlap to maximize capacity and a second cell area where they do not overlap to minimize stress. This spatial segmentation resolves the conflict between capacity optimization and stress reduction.
Solution Approach 2:
The substrate members are configured to dynamically adapt their arrangement based on location: overlapping in regions where stress is less critical and non-overlapping in regions subject to folding stress, allowing the structure to optimize both capacity and stress distribution.
Data Source
AI summary
An electronic device including a battery is provided. The battery disposed inside the electronic device includes a battery cell including a plurality of cell areas arranged at intervals therebetween and one or more folding areas that foldably connect a pair of neighboring cell areas, and a protection circuit portion extending from the battery cell and electrically connected to a printed circuit board (PCB) of the electronic device. The battery cell includes a plurality of substrate members stacked while being insulated through a separation membrane and a mixture layer applied to a surface of each of the substrate member, in which the substrate member are arranged without an overlapping area therebetween in a folding area.