Fuse Encapsulant for High Voltage Battery Environmental Isolation
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Solution Overview
Problem
Conventional surface-mounted fuses in battery packs for automotive applications face challenges due to environmental harshness, leading to inconsistent performance, dendritic growth, and increased packaging costs, as they are not adequately protected against humidity, temperature, and chemical agents, resulting in shortened lifespan and potential short-circuiting.
Innovation Solution
A conformal encapsulant made from a thixotropic precursor material is applied around the fuse to provide environmental resistance, ensuring the fuse remains isolated from the ambient environment during normal and compromised operations, preventing dendritic growth and allowing for the use of smaller, more cost-effective fuses with tailored voltage ratings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional surface-mounted fuse is used in high voltage battery packs, then the fuse can provide basic circuit protection, but the fuse becomes vulnerable to environmental harshness (humidity, temperature, chemical agents) leading to inconsistent performance and shortened lifespan
Solution Approach 1:
A conformal encapsulant coating is applied over the fuse component and surrounding circuit board area. This thin film shell provides environmental protection by isolating the fuse from humidity, temperature extremes, and chemical agents while maintaining the electrical functionality of the circuit. The encapsulant forms a protective barrier that prevents dendritic growth and corrosion without interfering with the fuse's operational characteristics.
Solution Approach 2:
The encapsulant acts as an intermediary protective layer between the fuse and the harsh environmental conditions. It mediates the interaction between the sensitive electronic component and the aggressive external environment (coolant, humidity, temperature), allowing the fuse to function reliably without direct exposure to harmful factors.
2Reliability
If the fuse is made larger to handle maximum pack voltage, then the fuse can provide adequate protection, but the increased size requires larger gaps between circuit pads making circuit design more complex
Solution Approach 1:
The encapsulant coating provides electrical isolation and arc containment, allowing the use of smaller fuses with appropriately tailored voltage ratings rather than requiring oversized fuses for maximum voltage protection. This reduces the space required around the fuse and simplifies circuit board layout while maintaining adequate protection capabilities.
3Volume of moving object
If a thin overcoating is applied to the fuse, then the fuse remains compact, but the overcoating cannot adequately seal the fuse from the harsh environment leading to dendritic growth and electrical corruption
Solution Approach 1:
The conformal encapsulant provides sufficient environmental sealing in a thin coating form factor. By applying the coating conformally (following the contours of the fuse and circuit board), adequate protective thickness is achieved without requiring large increases in component size. The encapsulant seals the fuse from environmental contaminants while maintaining compact dimensions.
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 encapsulant maintains the fuse in substantial environmental isolation, reducing the risk of electrical corruption and short-circuiting, enabling smaller packaging and lower costs while ensuring reliable voltage sensing and protection during high voltage events.
Implementation Method 1
A conformal encapsulant made from a thixotropic precursor material is applied around the fuse to provide environmental resistance
Data Source
AI summary
A battery pack, a device for sensing individual battery voltages in a battery pack and protecting the battery pack in the event of a circuit-breaking event, and a method for forming an encapsulant for the voltage-sensing circuit for use in a battery-powered automobile propulsion system. The battery pack includes numerous voltage sensing circuits with surface-mounted fuses and an encapsulant formed around each of the fuses. The encapsulant is robust enough to provide environmental isolation of the surface-mounted fuse such that the tendency of the fuse to form short-circuit connections to adjacent circuits is avoided under both normal battery pack operation and after a condition where the battery pack is compromised. The precursor to the encapsulant is made from a multiple layers of a traditional thin coating material or a single layer of a high-viscosity fluid to help maintain a minimum coating thickness around all exposed portions of the surface-mounted fuse, including the breech-prone corners.