EV Driving Range Improvement Depends on BMS Optimization
TI Develops New Wireless Protocol Dedicated to Wireless BMS
Maximize network availability without worrying about cable disconnection


As efforts to reduce exhaust gases are being made across industries to address worsening environmental pollution and resulting extreme weather events, the automotive industry is also shifting from internal combustion engine vehicles to electric vehicles (EVs).

According to a survey by IHS Markit last year, global automobile demand is expected to increase to 11.2 million units in 2025 and 31.1 million units in 2030, accounting for about 32% of total new car sales.

According to an August 2020 survey by EV Trend Korea, consumers are still hesitant to purchase EVs due to concerns about shorter maximum driving ranges (29%) compared to internal combustion engine vehicles and insufficient charging infrastructure (29%).

Texas Instruments (TI) held an online press conference on January 21 and announced a wireless battery management system (BMS) solution with a functional safety concept certified by Germany's TÜV SÜD.

The magazine conducted an additional written interview with TI Korea Managing Director Park Seo-min, who made the announcement at the time. “In order to increase the EV driving range to a level similar to or higher than that of internal combustion engine vehicles, battery efficiency must be improved,” said Executive Director Park, citing battery material innovation and BMS advancement as methods for doing so.

BMS is a key component that determines the efficiency, lifespan, and performance of electric vehicles. The cells inside the battery pack monitor and transmit temperature, voltage, and current data via an isolated CAN bus, differential daisy chain communication, or a proprietary solution.

◇ Wireless BMS solution, lighter and less expensive than wired

“It takes a lot of effort and money to separate each cell for connection and repair,” said Park Seo-min, managing director. “If the wiring is cut due to an accident, the entire battery pack may have to be replaced.” He explained why automakers and BMS solution companies are considering introducing wireless communication solutions.

Wireless solutions can overcome the problems of wired communication because they directly transmit battery cell information from the battery module to the BMS microcontroller (MCU). The car efficiency also increases because there are no heavy and expensive cables. However, in order to introduce a wireless solution, it must provide performance comparable to that of a wired system.

TI has developed a scalable wireless BMS solution based on the diverse design requirements of multiple automotive manufacturers. The solution includes: △'CC2662R-Q1' SimpleLink™ 2.4GHz wireless BMS MCU evaluation module, △software, △functional safety manual, △failure mode and effects analysis (FMEA), △failure mode, effects and diagnostic analysis (FMEDA), and TÜV SÜD concept report.

In particular, the 'BQ79616-Q1' battery monitoring and balancing IC mounted on the CC2662R-Q1 module filters system noise, accurately measures battery cell voltage and temperature, and transmits this information to the MCU.

◇ TI's proprietary wireless protocol increases wireless BMS availability

“TI’s wireless BMS functional safety concept addresses communication error detection and security issues while increasing reliability by using a novel wireless protocol dedicated to wireless BMS,” said Park Seo-min, executive vice president.

The TI Wireless BMS protocol is a time-division multiplexing solution that enables high-capacity data processing and provides low latency, providing advantages over other wireless standards, explained Park.

First, it integrates a frequency hopping solution to ensure immunity to electromagnetic interference, and enables the use of multiple parallel tracks and low-latency transmission. It also supports packet retransmission between nodes by maximizing scheduler efficiency.

In addition, it enables low-power network operation through real-time time slot-based scheduling. Additionally, it is equipped with various functions that enhance the level of security, ensuring safe data transmission, so devices can be installed robustly and safely within the network, said Managing Director Park.

“TI’s wireless BMS protocol has achieved network availability of over 99.999%,” said Executive Director Park Seo-min. “TI plans to standardize and popularize its wireless BMS protocol through its wireless BMS solution.”

TI’s proprietary deterministic protocol delivers high data throughput, enabling automotive and electronics manufacturers to develop battery modules supporting a variety of configurations, such as 32-, 48- and 60-cell systems, by connecting a single wireless system-on-chip (SoC) with multiple BQ79616-Q1 ICs.

It is also designed to support up to 100 nodes, provides low latency of less than 2ms per node, and time-synchronized measurements across all nodes.

The CC2662R-Q1 wireless MCU separates individual cell monitoring units, reducing the need for daisy-chain isolation components. The BQ79616-Q1 IC offers multiple channel options in the same package type, is pin-to-pin compatible, and supports reuse of existing hardware and software across all platforms.

◇ Capable of responding to the increasing wireless semiconductor confusion in the future

The number of semiconductors installed in automobiles is increasing day by day. Currently, about 200 to 300 semiconductors are installed, and it is predicted that level 3 autonomous vehicles will require more than 2,000 semiconductors.

When asked whether TI’s wireless BMS solution can sufficiently handle the crosstalk between the countless wireless semiconductors that will be installed in future vehicles, Park said, “It is possible because it is a frequency hopping and time division multiplexing protocol solution that can mitigate electromagnetic interference from various sources.”

He explained that this is because it allows for multiple retransmissions, with adaptive frequency hopping via reject and accept lists, and highly efficient scheduling, and because the battery enclosure itself acts as a Faraday cage to minimize electromagnetic interference from other sources.

When electromagnetic interference is minimal, the protocol can operate on multiple parallel tracks of interference-free subsets of frequency channels, allowing it to coexist with other networks in a single system.

◇ Wireless BMS solution ready for immediate use

Recently, some automakers are halting factory operations due to unstable supply of automotive semiconductors. “We are currently assessing the semiconductor supply situation in the automotive market,” said Park. “The wireless BMS solution design and all components included in the solution can be purchased through the TI website.”

“The BQ79616-Q1 IC provides accurate voltage measurements in system environments up to 800 V, simplifying the ASIL-D certification process and increasing driving range on a single charge,” he added. “When paired with the BQ79600-Q1 SPI/UART communication interface, its unique ‘start-up on fault’ feature enables full vehicle system shutdown, saving battery power and improving cell balancing.”

“TI is committed to helping automakers extend the driving range of hybrid electric vehicles (HEVs) and electric vehicles (EVs) while achieving the highest level of functional safety (ISO 26262 ASIL-D),” said Executive Director Park Seo-min. “We will continue to develop and launch products that provide high accuracy and flexibility, aiming to enhance the reliability and safety of HEV/EV systems.”