Folded Flexible PCB Battery Assembly With Non-Metallic Stiffener
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Solution Overview
Problem
Portable battery systems face challenges in increasing power capacity while maintaining user safety, reducing size, and minimizing weight, especially for conformal wearable batteries used by law enforcement and military personnel.
Innovation Solution
A conformal wearable battery (CWB) design featuring a plurality of battery cells affixed to a folded flexible printed circuit board (PCB) with a central stiffener made of non-metallic material, providing shock and vibration absorption while maintaining flexibility and electrical insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If additional battery cells or higher capacity battery cells are used to increase power storage capability, then the power capacity is improved, but the size and weight of the system increase, reducing mobility
Solution Approach 1:
The patent changes the material parameter of the stiffener from traditional metal to non-metallic materials (such as glass-filled composites or polycarbonate) with specific mechanical properties (flexural strength 410-560 MPa, elastic modulus 2.0-15 GPa). This parameter change reduces the weight of the stiffener while maintaining its structural function to prevent battery cell damage during flexing, thereby increasing power storage capability without proportionally increasing system weight.
Solution Approach 2:
The patent employs composite materials for the stiffener, specifically glass-filled composites or polycarbonate materials. These composite materials provide the necessary mechanical strength and flexibility to protect battery cells while being lighter than traditional metal stiffeners, thus resolving the contradiction between power storage capability and system weight.
2Reliability
If a durable and sealed housing is used to protect batteries from damage, then the reliability is improved, but the flexibility and shock absorption capability are reduced
Solution Approach 1:
The patent applies local quality by using a non-metallic stiffener with specific mechanical properties (flexural strength 410-560 MPa, elastic modulus 2.0-15 GPa) positioned between battery cells. This localized structural element provides differential protection: it maintains overall housing durability and sealed protection while enabling local flexibility and shock absorption at critical locations, allowing the housing to adapt to flexing requirements.
Solution Approach 2:
The non-metallic stiffener acts as a pre-positioned cushioning element between battery cells. Its specific elastic modulus (2.0-15 GPa) and flexural strength (410-560 MPa) allow it to absorb shock and vibration forces before they reach the battery cells, maintaining reliable protection while enabling housing flexibility.
3Adaptability or versatility
If the battery package is designed to flex or bend to accommodate intended usage, then the adaptability is improved, but the risk of damage to battery cells and PCB increases
Solution Approach 1:
The patent changes the material parameters of the stiffener to non-metallic materials with specific mechanical properties (flexural strength 410-560 MPa, elastic modulus 2.0-15 GPa). These parameter changes enable the battery package to flex and bend as required for adaptability while the stiffener's optimized mechanical properties prevent damage to battery cells and PCB during flexing operations.
Solution Approach 2:
The non-metallic stiffener with specific elastic modulus (2.0-15 GPa) and flexural strength (410-560 MPa) is positioned beforehand between battery cells to provide cushioning during flexing. This allows the battery package to achieve the required flexibility for adaptability while the stiffener's mechanical properties reduce the risk of damage to battery cells and PCB.
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 CWB design effectively absorbs shock and vibration, reduces the risk of damage to the battery cells and PCB, and enhances user safety while achieving a compact and lightweight form factor that meets stringent power and mobility requirements.
Implementation Method 1
a central stiffener made of non-metallic material, providing shock and vibration absorption
Implementation Method 2
The CWB design effectively absorbs shock and vibration, reduces the risk of damage to the battery cells and PCB
Implementation Method 3
a central stiffener made of non-metallic material, providing shock and vibration absorption while maintaining flexibility and electrical insulation
Data Source
AI summary
A battery system includes a plurality of non-cylindrical shaped battery cells arranged on, and physically affixed to, a flexible printed circuit board (PCB). The PCB may include a bend axis that facilitates folding of the flexible PCB to form an upper portion of the flexible PCB and a lower portion of the flexible PCB. A central stiffener may be positioned between the upper portion and the lower portion of the flexible PCB using an adhesive foam tape to form a battery assembly. The battery system may include a flexible housing with an internal cavity that receives the battery assembly. The central stiffener, and the adhesive foam tape, may provide a degree of rigidity and/or absorption to the PCB to reduce localized deformation of the PCB when the battery system experiences shock forces and to prevent damage to components of the battery assembly. The stiffener may be formed from non-metallic material. In addition, the stiffener may include a laminate layer with a plurality of fibers embedded within the laminate layer. The plurality of fibers may be oriented at approximately a 45 degree angle with a lower edge of the laminate layer.