As automakers consider new EV battery chemistries, battery management systems (BMS) with advanced semiconductor technology are more important than ever

Through continued innovation in battery management systems, we can help automakers design BMS architectures for emerging battery chemistries that make electric vehicles safer and more affordable.

As electric vehicles (EVs) gain popularity, advanced battery management systems (BMSs) are helping to overcome some of the key barriers to further adoption: range, safety, performance, reliability, and cost. Semiconductors are at the heart of such systems.

"Semiconductor technology makes up a much larger portion of electric vehicles than internal combustion engine vehicles," said Sam Wong, team leader at TI that develops electric vehicle battery monitoring products. a small part of the group."

According to a recent report from BloombergNEF, electric vehicles account for less than 5% of the global passenger vehicle market. Still, EVs are rapidly gaining market share, with most major automakers committing to shift to EV-focused product lines within the next five to ten years, moving toward a greener, more sustainable future. Advances in battery technology are a major consideration for mainstream consumers. TI is at the forefront of this field, driving automotive innovation with new technologies that enable engineers to use multiple battery chemistries and configurations. These advancements have led to improvements in the price, performance and reliability of electric vehicles, both in conventional and cutting-edge battery technology.

Get miles of range from millivolts

New battery chemistries present a big opportunity. Most electric vehicles are powered by lithium-ion batteries, which rely on the rare earth metal cobalt, which is in short supply. But now, much of the EV industry is starting to be cobalt-free using the substance lithium iron phosphate (LFP) as an alternative battery chemistry, which is more abundant, more sustainably mined, easier to use, and therefore a cheaper and more efficient replacement of.

But while the lower cost and relative abundance of iron make LFP a more sustainable option, the chemical also has a downside. Electric vehicles rely on measuring battery voltage drop to assess remaining capacity, which to the occupants means remaining range. However, unlike cobalt-based batteries, which have a steady drop in voltage as they discharge, the voltage drop in LFP cells is negligible, even as they approach full depletion, making predictions difficult.

"The flat discharge rate of the LFP requires voltage measurement accuracy that goes beyond the limits of modern semiconductor technology," said Mark Ng, system manager at BMS.

Traditional BMS devices measure battery voltage with an accuracy of about 5 millivolts, but in LFP batteries, this inaccuracy can result in about 25 percent error in range. Vehicles often report remaining range 25 percent less than their actual range, as manufacturers must take the issue of underestimating range into full consideration last week to avoid drivers being surprised by a dead battery on the highway.

This is where our cutting-edge technology comes into play. By leveraging our high-precision battery monitors, automakers can indicate a more accurate range.

"With our chip, the car won't tell you that you have 200 miles left when you actually have 250 miles left, but it might tell you that you have 230 miles left," Mark said, "when running on the same battery , BMS basically extends the range by 30 miles.”

This extra range is enough to ensure the viability of LFP batteries, giving automakers the confidence to turn to emerging chemistries to make electric vehicles more sustainable and affordable.

Balance Technology

In addition to extending the vehicle's range, accurate monitoring is critical to the safety and durability of the nearly 200 cells in an EV battery pack. If one battery is discharging faster than the others, the battery may be close to depletion even though the other cells in the pack are still charged. But getting too close to depletion can completely damage the battery, rendering it incapable of holding a charge, rendering the entire battery pack completely unusable. During charging, the problem is that one battery fills up faster than others. This could cause this battery to overcharge, potentially creating a dangerous overheating situation.

Our battery monitors are highly accurate and can detect early signs that the battery is at risk of over-draining or over-charging, then disconnect the battery to avoid over-discharging or discharging excess charge, allowing the entire battery pack to survive driving and charging maintain balance. These devices also monitor battery temperature increases, another sign of overcharging or other problems.

“The BMS provides a fine-grained monitoring network to detect the voltage, current and temperature of each battery,” Sam said. “This way, we can disconnect the battery from the system, or adjust the current flow in and out of the system.”

The BMS provides redundancy by using two independent sensors to measure the voltage and flag the system if there is a mismatch.

Even the task of cutting out the system battery has its own challenges and solutions. Higher battery voltage stacks, faster charging requirements, and more powerful traction motors all present unique challenges for these disconnect systems when it comes to power distribution, robustness, and safety in next-generation EVs.

Flexible and innovative

As manufacturers introduce new battery chemistries, more powerful battery packs and individual cells in different configurations, many manufacturers are launching electric vehicle product lines that utilize different battery combinations. Our portfolio offers multiple channel options in the same package, pin-to-pin compatibility, and fully utilizes existing software. Therefore, one of the important capabilities offered by our device portfolio is the ability to adapt to virtually any battery chemistry or configuration an automaker chooses to use, saving R&D costs, software development costs and time.

"If you're a manufacturer that offers multiple chemistries and configurations, it's critical to have multiple battery monitoring device options within the same product family," Mark said. "This ability to scale across platforms reduces the cost of a single unit the cost of electric vehicles and accelerate their time-to-market”

More BMS innovations to come. Our company is pushing the boundaries of voltage accuracy and integrating more control into each chip to unlock the true potential of automakers. Additionally, TI is conducting research to help ensure our BMS solutions are optimized to accurately support emerging battery types. “There may be another hundred different battery chemistries under study across the industry,” says Sam, “and we want to make sure our BMS products provide the flexibility to take advantage of each product’s characteristics. "

Committed to making the world a better place

Helping automakers make electric vehicles safer and more affordable is just one of the ways our innovators are working to make electronics more affordable and make the world a better place through semiconductor technology and fulfilling the company's vision. Each generation of innovation builds on the previous generation, making our technology smaller, more efficient, more reliable and more affordable. This is the advancement of engineering. This is exactly what we have been doing for decades and now.