Texas Instruments introduces chip-level diagnostics to improve grid-scale battery cell safety

From ESS News

Stationary battery energy storage systems (BESS) have multiple vectors for technology improvements, and battery management systems may be set to make a step-change improvement.

Standard battery management systems (BMS) monitor cells in a passive way, monitoring voltages and grading them against a curve in a ‘best guess’ scenario that does the job but has significant margins of error. For lithium iron phosphate (LFP) battery cell chemistries, and for a society that demands consistent improvements in fire safety, this basic metrics approach may no longer be sufficient to accurately determine internal cell health.

To address this, the industry has been working to integrate Electrochemical Impedance Spectroscopy (EIS) directly into battery monitor chips. In short, this creates a new way to actively monitor cell health.

One of the first to market is Texas Instruments (TI), with a device carrying a name only an electronics engineer could love: the BQ79826Z-Q1. This new chip offers EIS on the chip, and also offers a full 26-channel monitor, another first. The result is that system designers using the new chip with their BESS can shift electrochemical diagnosis from passive to on-silicon and apply algorithms to best understand health.

ESS News spoke with Henrik Mannesson, General Manager of Grid Infrastructure and Power Delivery at TI, about how the hardware integration impacts system design, software approach required, and how this changes both fire safety and the economics of grid-scale energy storage.

The tech solving the flat LFP curve

LFP has become the dominant chemistry for stationary storage due to its cycle life and safety profile, but its main disadvantage is an extremely flat voltage curve in its middle state of charge. It’s the same for electric vehicles, which TI is also targeting, though the focus here is stationary storage.

“The voltage curve of LFP batteries is flat in the mid-region,” Mannesson said. “When measuring in this region, it is difficult to determine from a standard voltage reading if a slightly lower voltage is due to permanent cell aging or simply a temporary state of charge. Standard systems rely on cycle-counting algorithms to estimate health rather than exact models.”

EIS addresses this by injecting an AC perturbation current or voltage into the cell to measure its internal AC impedance across multiple frequencies. “By creating an exact electrical model of each cell, we can separate state of charge from permanent chemical degradation, such as lithium plating or chemical changes,” said Mannesson.

Since impedance curves are sensitive to external noise, Mannesson’s team works with engineers on physical setups. “Wiring, connectors, and internal resistance all affect the measurement,” he explained. “To ensure a clean setup, we provide reference designs, evaluation modules, and graphical user interfaces. We want to ensure customers have accurate data before running multi-week thermal and degradation tests.”

Integrating the EIS engine on a single chip, no small task, then provides a “hardware fountain” that transmits what TI believes are cleaner impedance curves directly. By outputting this direct stream of raw chemical-level data, the chip removes the need for bulky add-on diagnostic hardware. For software, this shifts the playing field: developers can choose to run their own proprietary algorithms directly on the raw data, potentially bypassing the need to license specialized third-party diagnostic software altogether.

26-channels and bankability

Grid-scale batteries are transitioning from 52-cell modules toward 104-cell architectures. The BQ79826Z-Q1 monitors up to 26 cells in series, which is eight more than competing monitors.

For a 104-cell module, engineers can cover the entire pack with four of the new TI chips, minimizing the bill of materials, board space, and cost per channel.

This structural simplicity, along with other compliance features, takes a step in improving safety along with bankability. 

“These large systems are funded by pension and infrastructure funds looking for secure returns,” Mannesson said. “Providing reliable thermal runaway and aging data directly improves project bankability.”

Mannesson confirmed TI is currently sampling pre-production silicon of the new chip, and said full volume production is expected by the end of 2026. 

While full integration relies on clients, the first commercial energy storage systems utilizing the chip may ship as early as 2027.