Since the introduction of electronic technology into the automotive industry, the level of technology in vehicles has continuously increased, to the extent that cars will soon resemble supercomputers on wheels. The number of electronic devices in automotive applications is rapidly growing, with more sensors, computing power, and electrical energy being integrated into vehicles. This trend is expected to continue into the future, driven by ongoing advancements in electric and autonomous driving vehicles. However, the automotive environment poses unique challenges for electronic components, such as increasingly demanding requirements for high-temperature operation, critical reliability, and long service life. This article will introduce the challenges faced by next-generation automotive development and how the solid tantalum polymer capacitors introduced by YAGEO/KEMET provide unparalleled solutions to these challenges.
The automotive environment poses special challenges for electronic components
The automotive environment presents unique challenges for electronic components. Unlike many computing applications, automobiles experience extreme conditions, such as very low and high temperatures, extreme humidity, contamination, vibration, and shock. In addition to these harsh conditions, electronic components in automobiles are expected to have very long, stable, and reliable service lives, and must fail safely in the event of a malfunction.
Different electronic subsystems within vehicles present their own distinct challenges and requirements for the components used. Control and safety systems (such as anti-lock brakes, rearview cameras, and adaptive headlights) require components with exceptionally long service lives and high reliability. The powertrain (including components that generate power and transmit it to the road surface) requires components capable of withstanding high temperatures and severe conditions. In-vehicle electronic systems (including navigation, advanced diagnostics, and entertainment) require small, high-speed components.
In ADAS and autonomous driving applications, ADAS domain controllers and domain gateways are also critical application areas. Components such as Ethernet transformers within domain controllers and CAN common mode chokes within domain controllers need to meet AEC-Q200 requirements, suppress common-mode noise without attenuating the signal, and provide solutions that meet miniaturization and reliability demands. New automotive-grade polymer capacitors can offer potential solutions for automotive designers, meeting requirements for board space savings, high volumetric efficiency/miniaturization, and reliability.
Tantalum polymer capacitors are constructed with a tantalum (Ta) anode, a tantalum pentoxide (Ta₂O₅) dielectric, and a solid polymer electrolyte. This construction method offers several advantages, including high-temperature ratings and stability against temperature, voltage, and time. These characteristics enable tantalum polymer capacitors to meet and exceed the requirements of the AEC-Q200 automotive standard.
Taking automotive DC/DC converter applications as an example, since automotive electronics are typically powered by batteries, DC/DC converters are crucial for automotive applications. They step down the battery voltage (usually +12V DC) to more suitable voltage rails for electronic devices, such as +5V, +3.3V, +1.8V, or even lower. Conversion is often done in stages, for example, 12V to 5V, and then 5V to 3.3V. DC/DC converters provide the voltage for these power rails, while capacitors assist these converters in operating correctly and providing stable, clean power.
In a DC/DC converter circuit, capacitors are required at both the input and output. The input capacitor ensures instantaneous current is available during converter switching. The output capacitor ensures instantaneous current is available to the load (DSP, microprocessor, I/O, USB, etc.) during converter switching. In automotive applications, these capacitors must not only be designed to meet the circuit's capacitance needs but also selected to comply with the AEC-Q200 standard and withstand even higher standards of high temperature and harsh conditions.
Research, development, and innovation in tantalum polymer supercapacitors
In automotive solutions, YAGEO/KEMET is committed to the research, development, and innovation of tantalum polymer supercapacitors, achieving numerous results and patents in dielectric studies, impregnation studies, polymer formulations, polymer synthesis, and polymer coating research. YAGEO/KEMET's capacitor manufacturing processes comply with tantalum powder/wire processing compliant and feature a fully integrated tantalum supply chain, being the only vertically integrated, diversified, conflict-free tantalum supplier with stable operations configured to support growing product demand. YAGEO/KEMET offers many automotive-grade, high-reliability products that meet the needs of automotive applications, holding a 44% share of global production volume and leading in automotive, aerospace, and defense solutions.
The tantalum polymer capacitors (KO-CAP® series) introduced by KEMET are solid electrolytic capacitors with a conductive polymer cathode, featuring low Equivalent Series Resistance (ESR) and improved capacitance retention at high frequencies, minimizing power loss and unwanted noise. The KO-CAP series combines the low ESR of multilayer ceramics, the high capacitance of aluminum electrolytics, and the volumetric efficiency of tantalum into a single surface-mount package. Unlike liquid electrolyte-based capacitors, KO-CAP offers an extremely long service life, high ripple current capability, and can withstand the high temperatures encountered in automotive applications. For instance, the T599 tantalum polymer capacitor maintains excellent characteristics at temperatures up to 150°C, providing an ultra-long expected service life.
The AEC-Q200 standard is a global qualification standard for passive electronic components used in automotive circuits. It involves a stringent set of stress tests, and passing these tests grants components a "qualified" status. KEMET's T59x series of tantalum polymer capacitors easily meet and exceed these requirements.
The AEC-Q200 standard requires passive components to be tested at rated stress levels for an operational life of 1000 hours. KEMET's T599 series capacitors are rated for 2000 hours of operational life at 150°C. When properly derated for voltage and temperature, the T599 series can support high-temperature mission profiles of up to 8000 hours, and even ultra-extended mission profiles of 130,000 hours (15 years) under suitable conditions. The service life and failure rate equations for polymer capacitors can be used to validate their performance in these mission profiles.
Tantalum polymer capacitors for high-intensity and ultra-long mission profiles
The KEMET T599 Tantalum Polymer Capacitor series offers ratings at 100 kHz, featuring very low maximum series resistance, ranging from 25 mΩ to 150 mΩ, stable across a temperature range from -55°C to 150°C, with an ultra-long expected lifespan suitable for high-intensity and ultra-extended mission profiles.
Polymer T599 capacitors provide extended-life automotive solutions. KO-CAP® solid tantalum polymer capacitors offer unparalleled solutions for high temperatures, critical reliability requirements, and the long service life demanded by automotive environments. Specifically, the T599 tantalum polymer capacitor exhibits excellent characteristics at 150°C, with an expected service life extendable to 130,000 hours under specific conditions. This series offers a capacitance range of 33 to 150 µF and voltage ratings from 4 to 35 VDC, making them ideal for DC/DC converter circuits and other automotive application designs.
Tantalum polymer capacitors meeting diverse automotive application needs
In automotive applications, tantalum polymer capacitors can be used in sensing systems, such as radar/lidar sensing (e.g., Hands-On Detection, HOD), vehicle connectivity, and smart cockpit applications, where the T597/T598 (125°C) series can be employed. The T598 (125°C) series is suitable for autonomous driving/recognition applications, the T599 (150°C) series for the powertrain, and the T598 (125°C) and T599 (150°C) series for chassis and safety domains.
Furthermore, KEMET's KO-CAP® polymer SMD series includes numerous products designed for automotive and harsh environments, such as the T591/T597/T598/T599 series of high-humidity, high-temperature polymer electrolytic capacitors. These capacitors provide higher capacitance and ESR stability under harsh environmental conditions. Through design improvements and selected material upgrades, these capacitors offer a service life of 500 hours (T591) or 1,000 hours (T598, T599) at 85°C/85% RH rated voltage, fully comply with AEC-Q200 qualification testing, and have maximum operating temperatures of 125°C and 150°C, respectively. These capacitors are manufactured in ISO TS 16949 certified plants and are subject to Production Part Approval Process (PPAP)/Part Submission Warrant (PSW) and change control.
KEMET's KO-CAP® polymer SMD series features ultra-low ESR, full compliance with AEC-Q200 certification test plans (T597 FD 125°C, T598 125°C, T599 150°C), extended endurance test certification for T598/T599 (VR < 16 V) up to 2,000 hours at 125°C, dedicated H/T termination and surge current testing options (T598) for the defense and aerospace sectors, compliance with or exceeding EIA standard 535BAAC, tape and reel standard packaging per EIA 481, and halogen-free epoxy RoHS compliance.
Typical applications for the KO-CAP® polymer SMD series include decoupling and filtering in various market segments, particularly suited for automotive infotainment, ADAS, chassis and safety systems, and powertrain applications that must operate under harsh conditions like high humidity and temperature.
Taking the T598 as an example, it utilizes smaller components and compact module designs. Its robust and stable Ta₂O₅ dielectric layer reduces functional risk in applications. It is a low-loss component (single-digit ESR, high ripple current capability, extended capacitance retention over frequency), offers efficient DC/DC conversion with lower thermal resistance, and possesses stable electrical characteristics over time and temperature, supporting mission profiles exceeding 15 years with stable performance.
Conclusion
As next-generation vehicles advance towards electrification, intelligence, and high performance, in-vehicle electronic systems impose increasingly stringent requirements on power supply stability, durability, and miniaturization, bringing multiple challenges to electrical architecture design. Tantalum polymer capacitors, with their low ESR, excellent ripple current capability, long-term reliability, and compact size, can effectively improve power conversion efficiency, reduce power consumption and thermal loss, and ensure stable system operation in harsh environments. In the future, with the continuous advancement of smart driving and new energy vehicles, the tantalum polymer capacitors introduced by YAGEO/KEMET will play an even more critical role in vehicle power supply modules, control units, and advanced driver assistance systems, becoming key component solutions supporting innovation in next-generation automobiles.