Carmakers, battery suppliers vie for leadership in battery management

Battery Management Systems, or BMS, often called the “brain” of an electric vehicle battery, play a crucial role with integrated hardware and software to monitor and control battery cells while safeguarding against potential fires. While battery manufacturers excel in advancing battery technologies, the BMS field has traditionally been a specialized area for automakers, who develop and integrate their own systems into battery modules.

However, since a series of EV fire incidents in Korea, battery suppliers here, led by LG Energy Solution, have begun to creep into the battery safety solutions business, leveraging their advanced battery diagnostic tools – software tailored to support automakers’ BMS -- promising more sophisticated measures to prevent battery fires.

LG pricing battery software

According to industry sources, LG Energy Solution and Hyundai Motor Group’s BMS departments are negotiating service fees for LG’s upgraded battery diagnostic software using artificial intelligence and cloud technology. Previously offered free to ten automakers, including Hyundai, this tool operates independently from Hyundai’s BMS, providing crucial battery assessments since 2020. The latest version can analyze battery degeneration, predict lifespan and provide solutions for software-defined vehicles.

“With its extensive experience in battery production, LG’s battery diagnostic tool boasts far more advanced than Hyundai’s BMS technology,” said an official familiar with the matter on condition of anonymity. “From 2018 to 2022, LG filed 5,475 patents related to BMS, the most among Korean battery firms. It’s hard to imagine Hyundai Motor has developed top-tier technologies that don’t overlap with these patents.”

Beyond diagnostics, battery companies could also contribute to developing more enhanced BMS software than carmakers, the source added.

Samsung SDI, holding 5,215 patents during the same period, is betting even bigger. It is developing a next-generation battery pack equipped with BMS hardware, though production timelines remain undisclosed.

Despite technological advancements, battery makers face challenges in improving fault detection beyond 90 percent, largely due to car manufacturers’ unwillingness to share comprehensive BMS data. Battery companies often rely on their own data from testing charge and discharge cycles and dissecting EVs equipped with their batteries. “To better understand how conditions like temperature and driving modes affect batteries, we need more field data from EVs,” the source explained.

Power dynamics

Hyundai Motor is reluctant to share its extensive BMS data, citing potential “privacy violation” for car owners. However, the underlying reason is that taking control of the data is directly linked to profitability, according to industry experts.

“Similar to Tesla’s ambition to deliver a full self-driving service, automakers, including Hyundai Motor, do not outsource the development of their core technologies – BMS is one of them,” said Lee Hang-koo, head of the Jeonbuk Institute of Automotive Convergence Technology.

“As the era of software-defined vehicles draws closer, it only makes sense that Hyundai wants to launch subscription-based software update services (possibly charging the fees,) based on the data collected by BMS. So sharing that would mean handing over access to a lucrative business opportunity.”

The auto giant is also downplaying battery manufacturers’ expanding presence into the BMS business, asserting they can only do so much.

“While details of our deal with LG Energy Solution are confidential, LG’s diagnostic software primarily monitors batteries,” said an official from Hyundai Motor Group. “Our BMS, however, oversees broader structural issues, including battery impact on car parts and components.”

Hyundai Motor is upgrading its BMS to strengthen battery monitoring in three stages during EV driving and charging – detecting warning signs of voltage, current and temperature changes; diagnosing short circuit current; and alerting drivers.

Bigger ambitions

Recent fires involving EVs have intensified public scrutiny on systems preventing such catastrophic incidents, which some experts believe could make Hyundai Motor adopt LG Energy Solution’s diagnostic software.

Lee Ho-geun, a car engineering professor at Daeduk University, noted, “The public doesn’t care who takes control of BMS. They just don’t want their electric cars to burst into flames. To push through the EV chasm, Hyundai Motor needs all the help it can get -- best would be from the experts of batteries who actually built them.”

Lee, head of the institute, agreed and noted, “The carmaker previously rejected the land ministry’s request to share BMS data with battery companies. But now, it may face more pressure to disclose (them).”

Starting with LG’s paid battery service, battery manufacturers are seeking a stronger footing in the BMS sector, added Lee. “When EVs catch fire, battery companies bear greater compensation costs than automakers. They are vested in developing sophisticated battery safety software and potentially entire BMS to minimize fire risks. Just as Intel’s ‘Intel Inside’ became synonymous with computer safety, EVs could promote their safety with a tagline like ‘fire-free LG batteries.’”