Flexible Secondary Battery with Thermoplastic Layer for Wearable Devices
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Solution Overview
Problem
Portable information terminals and wearable devices with built-in secondary batteries face limitations due to their compact and lightweight design, which restricts battery capacity and efficiency in curved or complex external forms, leading to issues with bending beyond limits and internal short-circuits.
Innovation Solution
A flexible secondary battery design using a laminated film structure with a thermoplastic substance that becomes more flexible at human skin temperature, allowing the battery to adapt to complex forms while preventing overbending and internal short-circuits, and maintaining structural integrity when not in use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a secondary battery is designed to be flexible and changeable in form to fit complex exterior shapes, then the battery can efficiently utilize internal space of electronic devices with curved surfaces, but the battery may be bent beyond limits by strong external force, resulting in a too small radius of curvature and potential internal short-circuits
Solution Approach 1:
The patent applies this principle by using a flexible packaging structure with a laminated film configuration that allows the battery to bend and adapt to complex exterior forms while maintaining structural integrity. The flexible packaging includes a outer packaging layer with specific mechanical properties that prevent overbending and internal short-circuits while enabling the battery to conform to curved surfaces and fit efficiently within electronic devices of various shapes
Solution Approach 2:
The patent applies this principle by designing a flexible packaging structure with predetermined mechanical properties that provide protective cushioning against strong external forces before they can cause damage. The packaging structure is engineered to absorb and distribute bending stresses, preventing the battery from being bent beyond its limits and maintaining a safe radius of curvature to avoid internal short-circuits
2Strength
If a rectangular parallelepiped battery protected by metal can or hard resin is used, then the battery maintains structural integrity, but it cannot efficiently utilize internal space including curved surfaces of electronic devices with complex exterior forms
Solution Approach 1:
The patent replaces the rigid metal can or hard resin packaging with a flexible packaging structure made of laminated films that can conform to curved surfaces and complex exterior forms. This flexible packaging maintains sufficient structural integrity to protect the battery while enabling efficient utilization of internal space in electronic devices with curved surfaces, allowing the battery to adapt to various shapes and configurations
Solution Approach 2:
The patent applies this principle by using a laminated film structure consisting of multiple layers with different properties (including flexible polymer layers and potentially reinforcement layers) to create a packaging that combines the flexibility needed for curved surface adaptation with the structural integrity required for battery protection, replacing the traditional single-material rigid packaging
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 flexible battery design enables efficient use of internal space in devices with complex forms, prevents internal short-circuits, and maintains structural integrity, enhancing the flexibility and reliability of portable information terminals and wearable devices.
Implementation Method 1
a flexible secondary battery which includes a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode, a thermoplastic substance, and an electrolytic solution in this order from one side to the other side
Data Source
AI summary
A secondary battery suitable for a portable information terminal or a wearable device is provided. An electronic device having a novel structure that can have various exterior forms and a secondary battery that fits the forms of the electronic device are provided. The problem that strong external force unintentionally bends a secondary battery or an electronic device with a built-in secondary battery beyond the limits, resulting in a too small radius of curvature can be solved. The secondary battery has a structure in which a positive electrode and a negative electrode are included with a separator interposed therebetween. Between this structure and an exterior body, a thermoplastic substance which becomes flexible in the range around a surface temperature of human skin, higher than or equal to 30° C. and lower than or equal to 37° C., is provided.