[ TBOS TECH ] How We enable a High-Reliability Battery System

Safety and reliability are critical attributes for most commercial and industrial battery applications. In the ideal world, when a cell deviates from its normal behavior, you can disable it temporarily to reduce the risk of critical failures like a thermal runaway while increasing the lifespan of the cells and battery pack. 

Simply put, you don’t have to toss out the whole battery pack just because one cell is the weak link.

But, of course, disabling a single cell isn’t practical if you have to pry open a piece of equipment, take the battery pack out, replace a cell, and put everything back together. Not only is the task labor-intensive, but it also causes costly downtime. 

TBOS’s Dycromax™️ architecture allows operators to disable and enable cells remotely using our software and its “yellow flagging” functionality. Here’s how:

First, our battery management system gathers telemetries such as temperature, state of charge (SoC), current, capacity, and voltage information from the cells. Then, the TBOS software analyzes the data to identify indicators of potential issues and high-stress factors, such as deviations from typical usage temperature, wide SoC operation range, high currents, etc.

Why are these telemetries important?

For example, exposure to the edge of the allowed temperature range affects the performance and longevity of lithium-ion batteries. Also, keeping cells at the maximum allowed voltage for an extended duration causes accelerated degradation and lithium plating. The resulting lithium dendrite can cause internal short and lead to thermal runaway.

Our system uses telemetries, statistical analysis based on stored information, and/or state of health (SoH) value to yellow flag problematic cells. Then, it determines if they should be disabled to reduce the risk of critical failures while maximizing the longevity of the cells and the battery system. 

In particular, SoH is an important metric that most battery management systems don’t measure due to its complexity. But our advanced algorithm calculates it continuously using various parameters such as capacity fade, cycle count, and variations in impedance. 

Then, the yellow flagging function uses the analytics to automatically disable a percentage of cells with the lowest SoH value or highest stress factors in each charge/discharge cycle. The feature extends the lifespan of the battery pack by evening out the cells’ aging process. 

As such, our technology helps improve lifetime economics, enable extended warranties, and optimize the use of lithium, a finite and valuable resource. Additionally, it makes just-in-time maintenance actions possible — eliminating expensive and unnecessary just-in-case ones. 

Lastly, telemetries and SoH values are essential for supporting the second-life usage of battery cells to maximize the use of lithium.

The Dycromax architecture is key to supporting this yellow flagging capability. It allows flagged cells to be bypassed and re-engaged at any given point without rebalancing. 

For example, the operator can bypass yellow-flagged cells in typical use cases but enable them when it needs to maximize the available capacity or extend the lifespan of the battery pack. It can do so using our software-defined battery system with just a few clicks of the mouse.

The yellow-flagging features also play a critical role in the charging cycles. Here’s a brief explanation of how we charge rotating strings, and how the system keeps everything balanced:

To charge the battery, the system selects the cells with the lowest SoC viable for charging while filtering out yellow-flagged cells outside of the safe operating range. TBOS maintains and steers the system toward a balanced state, so charging will continue until all modules have reached maximum SoC.  

This groundbreaking capability allows operators to have a perfectly operational system even if a substantial number of cells are underperforming. They can enable flagged cells if they need extra power in a pinch — increasing system reliability without buying excessive capacity that stands idle most of the time.