Modernizing Remote Water Infrastructure with Edge AI and Ultra-Long-Life Lithium Batteries

By Ariel Stern & Rafael Yaar

Protecting, preserving and enhancing our nation’s critical infrastructure demands the implementation of Infrastructure 4.0 methodology to deliver smarter and more actionable data that enhances public safety, reduces the incidence of preventable contamination and overflows, and improves management control and reporting.

Critical applications include the incorporation of data from remote field assets such as reservoirs, distribution pipelines, control valves and supply tanks and many other applications involving water, energy and transportation networks.

With rapidly aging infrastructure, a growing backlog of deferred maintenance, operational stress, and compliance reporting challenges, there needs to be a transition from centralized data management and analytics to more decentralized solutions involving embed AI on the Edge technology powered by long-life lithium batteries.

Making Infrastructure Smarter

Physical edge devices support Industrial IoT data generation and transfer using artificial intelligence (AI) pattern recognition and machine learning powers to optimize productivity, connectivity, cost efficiency and management control (i.e. SCADA) while enhancing environmental quality and providing more actionable data for improved decision-making.

These physical edge devices are typically powered by ultra-long-life industrial grade primary (non-rechargeable) lithium thionyl chloride (LiSOCl2) batteries capable of supporting bi-directional wireless communications. These robust batteries are widely preferred for use in hard-to-access locations and harsh environments where the cost to replace a battery far exceeds the initial cost of the device itself.

The system design considerations are all highly interrelated, requiring comprehensive end-to-end solutions that address the following key questions:

  • Is the solution smart, intuitive, and enhance real-time decision-making?
  • Is it a comprehensive end-to-end solution that is scalable and flexible?
  • Is the data and the device cybersecure?
  • Is the ideal battery being specified?

Here is a summary of important technical issues related to the deployment of a wireless Edge device:

The Importance of Real-Time Data Intelligence

Enhanced data intelligence enables smart data to become more actionable, visual, connective and interoperable, and scalable to seamlessly integrate the newest technologies with legacy platforms such as PLC and TRU, all without requiring intensive coding.

Cloud-based solutions are inherently slower and less secure compared to AI on the Edge technology that provides more immediate response, including the potential for redundant, self-healing wireless mesh networks.

Comprehensive End-to-End Solutions Make Sense

Partial solutions are inherently costly and inefficient versus comprehensive end-to-end solutions that are far more modular, scalable, flexible, and sensor agnostic, able to quickly adapt to dynamic market conditions and future growth opportunities.

Optimized end-to-end solutions are also smarter and more secure, able to adapt to virtually all existing wireless technologies to accommodate multiple configurations (analog, serial and discrete input) while seamlessly integrating third party software. These intelligent solutions utilize simple, autonomous, plug-and-play wireless Edge devices that do not require any specialized coding skills. Use of ultra-long-life batteries further enhances their reliability and increases their return on investment (ROI) by extending system operating life and by reducing long-term maintenance costs.

Cybersecurity Is Essential

The threat of cybercrime is on the rise, so military grade cyber security must be deployed to protect various points of access.

One potential access point involves intercepted communications that can corrupt the device’s configuration or modify the data. Bluetooth communications channels can also be compromised to gain unauthorized configuration access. Additionally, API sessions can be hacked to gain programmatic access to specific user accounts.

Mitigating these risks requires a best practices model that combines secured hardware and software with fully encrypted communications. The gold standard for protecting data integrity is TLS v1.3 encryption libraries and firmware.

Table 1
Table 1 – Comparison of primary battery chemistries.

The Importance of Choosing an Industrial-Grade Lithium Battery

Specifying a robust power source is essential for any low-power wireless device since battery failure leads to system failure.

There are two types of low-power devices: those that draw average energy (background current) measurable in microamps, along with pulses in the multi-Amp range. These pulses typically power bi-directional wireless communications, requiring the use of an industrial-grade primary (non-rechargeable) lithium battery. If the device draws average energy (background current and pulses) measurable in milli-amps, then it may require the use of an energy harvesting device in combination with a Lithium-ion (Li-ion) rechargeable battery.

Every application has unique power requirements, with multiple variables, including: sampling frequency; the amount of energy consumed while in ‘active’ mode; cell capacity and energy density: minimizing losses caused by long-term exposure to extreme temperatures; and other factors impacting battery self-discharge.

While numerous primary battery chemistries are used to power wireless devices (see Table 1), bobbin-type LiSOCl2 chemistry stands apart for delivering the highest capacity and energy density, widest temperature range, and lowest annual self-discharge rate, making it ideal for long-term use in remote locations and harsh environments.

Understanding How to Reduce Battery Self-Discharge

All batteries experience some amount of self-discharge, as chemical reactions exhaust available capacity even when a cell is disconnected or in storage. The rate of annual self-discharge varies based on the cell’s current discharge potential, the quality of the raw materials, and the ability to harness the passivation effect.

Passivation occurs when a thin film of lithium chloride (LiCl) forms on the surface of the lithium anode to limit reactivity. Whenever a load is placed on the cell the passivation layer initially causes high resistance and a temporary dip in voltage until the discharge reaction starts to dissipate the LiCl layer: a process that repeats each time the load is removed.

The amount of passivation can vary based on how a cell is manufactured, the quality of raw materials, the cell’s current capacity, and the length of time in storage. Other factors include storage and discharge temperature and prior discharge conditions, as removing the load from a partially discharged cell increases the level of passivation relative to when it was new. Passivation increases battery longevity. However, too much of it can be problematic if it overly-restricts energy flow.

Standard bobbin-type LiSOCl2 cells are uniquely able to harness the passivation effect, but cannot generate high pulses due to their low-rate design. This challenge can be overcome with the addition of a patented hybrid layer capacitor (HLC). The standard bobbin-type LiSOCl2 cell delivers the low-level background current while the HLC delivers the high pulses needed to power bi-directional communications. The HLC also features a unique end-of-life voltage plateau that enables ‘low battery’ status alerts.

Other factors can influence battery performance, including: current consumption in ‘active’ mode (the size, duration, and frequency of pulses), how much energy is being consumed in ‘stand-by’ mode (the base current); storage time (as normal self-discharge diminishes capacity); prolonged exposure to extreme temperatures during storage and in-field operation; and equipment cut-off voltage (exhausting cell capacity and/or extreme temperatures can cause voltage to drop too low to allow the device to operate).

All Batteries Are Not the Same

Comparing seemingly identical batteries can be difficult, as a higher self-discharge rate may not become apparent for years, and predictive models tend to underestimate the passivation effect as well as long-term exposure to extreme temperatures. Significant differences exist between a superior quality bobbin-type LiSOCl2 cell that features a self-discharge rate as low as 0.7 percent per year (able to last up to 40 years) and an inferior quality cell with a self-discharge rate of up to 3 percent per year, thus limiting its life to 10-15 years.

Because these differences are not easily distinguishable, careful due diligence requires well-documented, long-term test results and field data comparing roughly equivalent devices under similar loads and environmental conditions. Enhancing critical Infrastructure by combining secure AI on the Edge technology with extended life lithium batteries will improve decision-making while also reducing your cost of ownership.

Some Case Study Examples

With fresh water being a precious commodity, the municipal water system of Orange County, Florida, relies on reclaimed wastewater to irrigate golf courses, resorts and residential gardens. Dependent on the same reclaimed water storage tanks, residential customers did not have sufficient water for their gardens when golf resorts were watering the greens. Ayyeka Wavelet devices track water usage at golf courses and resorts to coordinate water supplies for residential customers. Additionally, detailed tracking of reclaimed water usage enables Orange County’s Public Works Department to proactively plan for the placement of additional reclaimed storage tanks to meet gradually increasing demand. Highly energetic Bobbin-type LiSOCl2 batteries support bi-directional wireless communications while ensuring maximum uptime with less frequent battery change-outs.

With more than 600 miles of water mains, Erie County’s pressure reducing valves (PRVs) serve to prevent stress on water mains that can lead to pipe leaks and bursts, which is especially critical to a 100-year-old system that serves more than 1 million people. Previously, service crews lacked data intelligence to anticipate potential ruptures to the main water line. Ayyeka delivered a comprehensive end-to-end solution using Wavelet devices to continuously monitor pressure levels in PRVs, making sure they function optimally and providing automatic text message, email, or automated phone call alerts if pressure levels begin to drop. Field Asset Intelligence (FAI) software is used to detect small leaks before they lead to costly and disruptive water main ruptures. This is a nationwide problem, as the American Society of Civil Engineers concluded that leaking pipes are responsible for the loss of 6 billion gallons of treated drinking water each day.

Ariel Stern is co-founder and CEO of Ayyeka Technologies.

Rafael Yaar is regional marketing and sales manager for Tadiran Batteries.

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