EVs face technology challenges and require a path to sustainability
Automotive markets are evolving rapidly as electric vehicles (EVs) continue to grow market share and as more autonomous driving functions come on-line.
Currently, EVs face a host of challenges including cost, sustainability, range, charging capabilities, weight, and efficiency, amongst others. If EVs are to replace combustion engine cars these challenges need to be addressed.
While the major cost of an EV is the battery, these costs have been falling and are expected to continue to fall. This is mainly due to advances in battery technology. For example, the use of LFP (Lithium Iron Phosphate) batteries, which are significantly cheaper than other battery chemistries such as NMC (Nickel Manganese Cobalt) have reduced EV prices in the last few years. They also offer longer life time, perform better in both low and high temperature extremes, and most importantly have a higher thermal tolerance that significantly reduces the risk of thermal runaway. Further, LFP batteries avoid the scarcity and geopolitical supply chain issues of NMC batteries. The only down side is that LFP battery cells have a much lower energy density than NMC chemistries. However, as LFP cells are safer they can be packed closer together, requiring less separation than NMC cells, resulting in equivalent capacity LFP battery packs having an energy density of about 15 percent less.
To further drive down costs many new battery technologies are on the horizon such as solid-state and sodium-ion. Further out, recycling of Lithium should also bring down prices.
While advances in battery technology take time, other areas offer more immediate savings, such more efficient drive trains, lighter vehicles, SiC power semiconductors to drive efficiency, and intelligent battery monitoring. For example, 800-V EV bus drive systems based on SiC have enabled faster charging and reduced EV weight, allowing car makers to produce vehicles with longer driving ranges for premium models. In general, SiC MOSFETs provide higher efficiency, smaller components, reduced weight, and extended driving range compared to silicon-based products.
Other technologies such as V2X, ADAS, software-defined vehicles (SDVs) and autonomous driving also make EVs more appealing to consumers. While full autonomous driving is proving to be a multi-decade challenge, ADAS is increasingly being driven by safety and legal requirements as well as consumer demand and will eventually lead to autonomous vehicles.
Some specific recent technology developments that are set to influence the EV market in the short term are highlighted.
Battery traceability goes wireless
In terms of sustainability and traceability, intelligent real-time battery monitoring is key to the future EV market. Dukosi is the only company to bring reliable, secure wireless battery cell monitoring product to the volume market. The Dukosi Cell Monitoring System (DKCMS) is designed to provide continuous traceability for safety critical, next generation battery systems at the battery cell level in EVs and energy storage.
A unique contactless battery cell monitoring technology DKCMS consists of the DK8102-AQ-25 Cell Monitor IC, DK8202-AR-25 System Hub chip, the Dukosi API and C-SynQ® communications protocol. A Cell Monitor IC mounted directly onto each cell provides accurate monitoring of key operating parameters such as voltage and temperature along with necessary cell balancing functionality and diagnostics. The System Hub IC manages the bidirectional data transfer between all of the Cell Monitors and the BMS Host using Dukosi’s proprietary C-SynQ via a single bus antenna. C-SynQ provides a highly secure and extremely robust and reliable communication, with predictable latency and synchronizes all Cell Monitor measurements for optimal pack performance.
The wireless battery monitoring system can improve usable energy per cell of over 20 percent and SoC estimation per cell of about 4 percent. As cell monitoring is very accurate, the technology mitigates range anxiety, enhances safety and improves pack lifetime. It can monitor battery cell data 24/7 and keep the data over the lifetime of the battery providing cradle-to-grave traceability for EV batteries. The technology also enable the state of the battery can be ascertained for second life opportunities.
As the battery monitoring system is wireless it eliminates the need for wiring, reducing weight of the battery pack. It overcomes the limitations of traditional wired and far field wireless systems and frees physical design constraints to provide greater safety, design flexibility and scalability.
Silvana Rulet, Best Practices Research Analyst, Frost & Sullivan, said: “With its chip-on-cell sensing platform, Dukosi addresses an unmet market need ahead of competitors. It provides insights into each battery cell through embedded software, onboard processing, and memory. Moreover, this technology allows for accurate, contactless, and synchronous communication between cells and the main battery management system, enabling organizations to monitor the status, health, and performance of every cell in real-time.”
SiC to drive efficiency, cut weight in EVs
Companies such as Rohm, Infineon, and ST and are actively developing SiC MOSFETs for traction inverters used in EVs. SiC MOSFETs provide higher efficiency, smaller components, reduced weight, and extended driving range compared to silicon-based products. These benefits are critical for achieving widespread adoption of EVs. SiC demand is growing rapidly not just in automotive but also in renewable energy, industrial and data center applications.
Infineon announced in August the official opening of the first phase of a new fab in Malaysia, Kulim 3, that it claims will become the world’s largest and most competitive 200-mm SiC power semiconductor fab. Infineon has secured design wins with a total value of approximately five billion euros and has received approximately one billion euros in prepayments from existing and new customers for the ongoing expansion of the Kulim 3 fab. Notably, these design wins include six OEMs in the automotive sector.
Directly addressing the automotive market, ST has just launched its Generation 4 SiC MOSFETs, which will be made available in 750-V and 1200-V classes and will improve energy efficiency and performance of both 400-V and 800-V EV bus traction inverters, bringing the advantages of SiC to mid-size and compact EVs — key segments to help achieve mass market adoption.
To accelerate the development of SiC power devices through its vertically integrated manufacturing strategy, ST is developing multiple SiC technology innovations in parallel to advance power device technologies over the next three years. The fifth generation of ST SiC power devices will feature an innovative high-power density technology based on planar structure. ST is at the same time developing a radical innovation that promises outstanding on-resistance RDS(on) value at high temperatures and further RDS(on) reduction, compared to existing SiC technologies.
ROHM and Geely Automobile Group Co., Ltd., a leading Chinese automobile manufacturer have a strategic partnership to develop advanced technologies in the automotive field. Geely and ROHM have been collaborating since 2018, beginning with technical exchanges, then later forming a strategic partnership focused on SiC power devices in 2021. Geely is working to extend the cruising range of electric vehicles while reducing battery costs and shortening charge times by developing high efficiency traction inverters and onboard charging systems that adopt ROHM’s advanced power systems centered on SiC power devices. To date, ROHM has announced that power modules equipped with 4th generation SiC MOSFET bare chips for the traction inverters are being used in three models of the ZEEKR EV brand from Zhejiang Geely Holding Group.
ROHM has also recently entered into a long-term agreement with United Automotive Electronic Systems Co., Ltd., (UAES), a leading Tier 1 automotive supplier in China, for SiC power devices.
Software development and formal methods
Providing ADAS and developing software for future autonomous vehicles involves mission critical applications. One way to ensure near 100 percent reliability is through formal verification, which mathematically guarantees software functionality. TrustInSoft, a leading provider of advanced software analysis tools, offers its recently launched Formal Verification Services (FVS), an expert-driven solution designed to enhance the security and reliability of software written in C/C++ languages.
FVS enables subscribers to de-risk several phases of their development processes by quickly verifying that code is bug free, thus reducing the likelihood of costly errors and improving overall operational efficiency.
“Our Formal Verification Services are designed to provide enterprise organizations with in-house formal methods expertise to enhance workflows without disruption while providing unparalleled mathematical proof of the absence of runtime errors and vulnerabilities,” said Caroline Guillaume, CEO of TrustInSoft. “By leveraging our advanced formal methods and the TrustInSoft Analyzer, we can deliver precise and exhaustive analysis that enhances our customer’s overall software security and reliability.”
FVS offers enterprise organizations a complete formal verification solution that extends their internal teams with TrustInSoft’s formal verification experts. These experts develop and integrate custom analysis drivers tailored to the specific source code and project requirements of each customer. FVS ensures comprehensive and accurate abstract interpretation analysis, reducing the need for in-house expertise in formal methods.
This is an important concept for the development of autonomous vehicles and ADAS as such software will need to bug-free for both safety and legal reasons.
Timing, safety and software defined vehicles
SDVs offer a path to flexible design, leveraging of common hardware components, the ability to add functionality as needed without changing the underlying hardware, porting designs to higher performance hardware for future vehicles, or allowing designers to reuse parts of design without starting from scratch. This leads to lower costs and and an easy upgrade path.
Addressing the emerging SDV and autonomous driving market as well as ADAS and complexity of timing in the next-generation of vehicles, SiTime has developed the industry’s first fully integrated clock system-on-a-chip (ClkSoC), designated Chorus™ Automotive. FailSafe™ technology provides built-in fault monitoring mechanisms for the entire clock generation signal path and enables ease of functional safety design by providing programmable end-to-end safety monitors. The device integrates a MEMS resonator, oscillator and advanced safety mechanisms into a single package. This integration simplifies system timing architecture and accelerates functional safety development time by up to six weeks. The technology delivers up to 10x higher performance in half the size compared to standalone oscillators and critical diagnostic coverage to achieve functional safety metrics more easily.
If the clock for a critical component fails, catastrophic failures can occur, making fast fault notification an important part of the automotive system design. Chorus Automotive can shave off critical milliseconds by reporting clock failures far earlier. Further, it addresses the limitations of legacy quartz-based clock generators by providing up to 10X lower failure rates with advanced diagnostics.
The SDV will ultimately be a datacenter-on-wheels. SDVs will access large amounts of data in real-time from a multitude of sensors including cameras, LiDAR, radar, presence detection and so on. This data needs to processed quickly and decisions made almost instantaneously to ensure safety of the occupants of the vehicle and other road users. SDVs will have to support 1000s of tera operations per second (TOPS) and consequently require a synchronous precision timing network with guaranteed reliable performance under shock, vibration, and extreme weather, with lifetimes spanning decades. Even next generation vehicles are facing challenges in data processing and implementing advanced driver aids as the number of sensors used soars.
Conclusion
As the automotive industry transitions to EVs and implements more an more functionality such as ADAS and autonomous driving, innovative technology is required to address these challenges. Key to making EVs mainstream and ultimately SDVs will require advances in power efficiency, battery technology and monitoring, software development for missions critical applications, and reliability, amongst others. Sustainability, second life use of batteries and recycling will also be a key consideration, not only for the environment but also in bringing cost down. A lot of small incremental advances can lead to a significant reduction in EV cost and weight, while driving up effecincy and consequenly range.
Another important aspect of software development is the expectation that and advanced car should be as intuitive and easy to use as a smartphone. This implies robust GUIs to interface with the driver and reliable infotainment systems. In the end, the the key differentiator for car manufacturers besides performance, range and cost will be the interface with the driver, analogous to a smartphone.
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