Enhancing Li-Ion Battery Safety: The Imperative of Rupture Disc Integration for Overpressure Mitigation
Author: OsecoElfab
Introduction
The rapid growth of Li-Ion batteries in various industries, including electric vehicles, portable electronics, and renewable energy storage, brings to the forefront a critical safety concern: thermal runaway and its potential to trigger overpressure explosions. To address this imminent threat, the incorporation of rupture discs into Li-Ion battery designs emerges as a proactive measure.
The Regulatory Landscape: Commercial vs. Military Vehicles
While there is not any current legislation mandating specific pressure relief solutions for battery packs in commercial and commuter vehicles, military vehicles are bound by the rigorous standards of MIL-PRF-32565. This stringent regulation enforces the inclusion of pressure relief mechanisms and testing, to safeguard against overpressure scenarios, highlighting the imperative of such measures for overall safety. Most battery packs, seen in the market today, offer a plastic housing breathing type vent as a solution.
Pressure Equalization vs. Pressure Relief
Pressure equalization, commonly referred to as “breathing,” aims to maintain pressure balance within a battery enclosure due to environmental or elevation changes. Think of a plastic gas can in the garage in the summer months vs winter (it can be expanded or contracted in shape). However, pressure equalization alone does not mitigate overpressure risks. Rupture discs provide active pressure relief by opening at predetermined thresholds, exhausting excess pressure, and preventing catastrophic explosions.
Sizing Rupture Discs and Testing
Sizing rupture discs for Li-Ion battery packs presents unique challenges due to varying battery chemistries, sizes, and configurations. Unlike conventional applications, there isn’t a one-size-fits-all formula for rupture disc sizing in battery systems. To ensure the relief area of a rupture disc is sufficient for the battery enclosure and cell configuration, thorough testing is essential. Prototyping and testing different rupture disc sizes and configurations under simulated thermal runaway conditions can provide valuable insights into the ideal rupture disc design for a specific battery pack. The utilization of multiple rupture discs strategically positioned within a battery pack can enhance safety redundancy and optimize pressure relief effectiveness.
Value Propositions of Rupture Discs
The integration of rupture discs into Li-Ion battery designs brings forth a multitude of advantages:
- Low Profile Design: Rupture discs occupy minimal space, making them suitable for compact battery pack configurations.
- Holder-Less Designs: Some rupture discs require no complex holders, streamlining integration and reducing potential failure points.
- Swift Opening Times: Rupture discs can open in as little as four milliseconds, ensuring rapid pressure relief during thermal runaway incidents.
- Full Bore Openings: Upon rupture, these discs provide unobstructed openings for efficient gas venting, curbing pressure escalation.
- All-Metal Configurations: Rupture discs are typically an all-metal design creating corrosion-resistance, guaranteeing long-term reliability without degradation.
- Custom Designed: Rupture discs are not an “off the shelf” item and are custom engineered and manufactured to meet customer specifications in fit, form, and function.
Conclusion
Integrating rupture discs into Li-Ion battery designs to counteract overpressure explosions resulting from thermal runaway events, marks a pivotal stride in enhancing battery safety. The distinction between pressure equalization and pressure relief highlights the efficacy of rupture discs in actively preventing catastrophic failures. The absence of legislated mandates for commercial vehicles underscores the need for proactive safety measures. The challenge of sizing rupture discs underscores the importance of rigorous testing and simulation, while the diverse benefits of these discs, including low profile designs, rapid opening times, holder-less configurations, and all-metal construction, fortify their status as indispensable safety components. By integrating rupture discs, the industry underscores its commitment to advancing Li-Ion battery safety, ensuring the sustainable growth of these technologies while minimizing risks to both users and assets.
OsecoElfab is a leading global provider of pressure relief solutions, headquartered in the USA and UK. Our purpose is ‘Protecting life. Solutions for a safer, cleaner world.’ Following this purpose, we manufacture rupture discs, explosion vents and burst detection systems to protect people, plant and the environment.
Our innovative solutions for lithium-ion battery protection include rugged, space-saving, and ultra-low-profile designs, as well as dual-function breather-and-rupture disc devices. For the energy storage market we offer specialist explosion panels designed to withstand harsh and outdoor environmental conditions. Our customer-focused services include highly specialized engineering and design consultation, product training seminars, site surveys and a stock consolidation program.
Our two manufacturing facilities in the USA and UK are supported by six regional sales offices and over sixty approved representatives worldwide. Alongside the battery and energy storage markets, our key sectors include chemical processing, pharmaceutical and biopharmaceutical manufacturing, electricity transmission and distribution, powder and bulk handling, gas generation and handling, cryogenics, medical, and aerospace. OsecoElfab is part of the Halma Group, a FTSE 100 company with over 50 subsidiaries worldwide.