Chroma ATE Inc. (Chroma) recently held a seminar on electric vehicle (EV) and energy storage testing technologies. Reflecting on industry trends and measurement techniques, Leo Huang, Chairman of Chroma, said, "Chroma has been established for nearly 40 years. Throughout this time, power electronics testing has always been the most important and successful field for Chroma's development. From power testing for information and communications technology (ICT) products to aviation-related products, Chroma's instruments are capable of testing a wide spectrum of devices. About 15 years ago, our collaboration with a well-known American EV manufacturer opened the gateway for Chroma to enter the EV industry." With the increasing importance of net-zero carbon emissions, and driven by proactive efforts from governments worldwide, EVs have become an important application field that will continue to grow this year. As with traditional fuel vehicles, protecting the safety of EV passengers and drivers is a paramount concern. This need for safety in turn heightens the importance of EV testing, which has prompted Chroma to develop a comprehensive range of EV test solutions.
To Meet Changing Demands for Charging, Chroma and ITRI Provide a Comprehensive Test Solution
Jason Chen, Senior Manager at Chroma, continued by noting that the most widely known standard in the market is the functional safety standard ISO 26262, which has been in place for quite some time now. The standard is also applicable to fuel vehicles, and as the world embarks into the age of electric cars, it will grow even more important. In this regard, Chen specifically mentioned the concept of PHIL (power hardware-in-the-loop). PHIL is essentially a semi-simulation system that is quite suitable for testing the electronic control unit (ECU) of EVs. Even though in the past there was hardly any demand for high-power system testing for fuel vehicles, this has changed with the advent of EVs. This is why Chroma utilizes test equipment to simulate high-power output/input behavior related to the entire vehicle, so as to run practical tests with high voltages and currents. Besides battery module testing, Chroma provides test systems for a wide range of applications, from AC/DC charging stations, motor drivers, OBC/DC-DC converters, to even the battery pack itself. These systems can all be adjusted to accommodate different testing conditions based on specific requirements.
Echoing Chen's remarks, Steve Cheng, Deputy Product Manager at Chroma, shared more insight into EV charging specifications. Based on Cheng's observations, the design of on-board chargers (OBCs) will evolve towards bidirectional charging/discharging capabilities. Furthermore, due to future demands, the alternating current (AC) charging power will also be upgraded from the mainstream 11kW to 22kW, with voltages exceeding 600V. As for the direct current (DC) power range, it will be divided into different levels, namely 240kW, 360kW and 480kW.
Dr. Kao-Hone Chu from the Industrial Technology Research Institute (ITRI) explained the importance of charging communication by elaborating on the DC charging process of EVs and the corresponding protocol, the Combined Charging System (CCS). Dr. Chu analyzed the reasons why charging communication is so important. Firstly, it is essential for the power supply system to confirm that the recipient is an EV. Hence, communication is necessary for mutual verification. Secondly, the charging systems currently in the market are very diversified, which requires each system to possess significant operational flexibility. Through communication, parameters of both the charging infrastructure and the electric vehicle can be adjusted accordingly to achieve efficient charging functionality. Last but not least, charging communication helps prevent unnecessary accidents from occurring.
As for testing, compatibility testing with multiple brands and manufacturers is quite a challenge. In the early stages of EV market development, less time was spent on compatibility testing due to fewer available models and brands. Due to the increase in the number of vehicles and brands, even with the use of communication compatibility testing, the process remains time-consuming. Therefore, adopting automated testing is a more efficient approach. That's why ITRI has sought assistance from Chroma to develop an automated test system. This solution eliminates the need for physical vehicle testing. Additionally, it allows the adoption of various abnormal conditions when performing validation, which is currently a common scenario in the collaboration between ITRI and Chroma.
@To Accelerate the Development of Battery Management Systems, Test Automation is Inevitable
Jason Lin, Deputy Product Manager at Chroma, explained that testing the battery pack in electric vehicles can be divided by the components under test: the battery pack itself, the battery management unit (BMU), battery modules and cells, battery disconnect unit (BDU), and thermal management system. Based on Chroma's observations, the development of the battery management system (BMS) in electric vehicles is primarily led by EV manufacturers, as battery manufacturers and BMS suppliers generally need to cater to requirements defined by EV manufacturers.
Lin further mentioned that the market has seen the adoption of unified diagnostic services (UDS), not only in EVs, but also in other products like electric scooters. This allows EV manufacturers to provide more convenient aftersales services. In terms of battery pack design, traditional approaches focus mainly on preventive measures, like managing parameters such as voltage and temperature, or enhancing heat dissipation capabilities. However, in recent years, flame-retardant and damage mitigation designs have been implemented to ensure that a battery pack will not combust. Flame-retardant materials have been installed in between battery cells so that if one cell experiences thermal runaway, other cells are not affected. As for damage mitigation mechanisms, fire suppression devices are installed that can directly extinguish fires in the event of cell failure. Meanwhile, passengers are also alerted to promptly evacuate the vehicle.
Analyzing developing trends in testing practices, Sharman Chang, Senior Product Specialist at Chroma, noted that EVs are projected to undergo an annual growth of approximately 20% from 2020 to 2030. This signifies the increasing market demand for more batteries, which in turn leads to the emergence of automation and intelligent solutions in manufacturing and testing processes. The benefits of automation include maintaining consistent quality and optimizing throughput of the entire assembly line according to production goals of different factories. By standardizing and digitizing the testing process, automation reduces the need for manual labor and increases labor efficiency. After automated testing is performed, the data can be integrated with the manufacturing execution systems (MES) and uploaded onto the cloud to provide feedback to the product development team. Such integration will facilitate product corrections and accelerate the development process.
In terms of electrical safety, Kenny Ni, Product Director of Chroma, pointed out that to prevent harm to the human body, the general electrical safety test mainly includes 4 items, which are Hi-pot/withstand voltage test, insulation resistance test, ground bond test, and leakage current test. The electrical safety standards, that are related to electric vehicles, include GB18384, UL 2580, IEC 61982, IEC 62133, IEC 62660, UL2251, IEC62196, UL2202, UL2594, IEC61851-1, and UL9540. The main testing points include: (1) between the hazardous voltage circuits and the enclosure of DUT, (2) between the hazardous voltage circuits and the accessible non-current carrying conductive parts or low-voltage circuits of the DUT, (3) between the hazardous voltage charging circuit and the charging connections, (4) between the hazardous voltage circuits and all accessible parts, (5) between the live part and the metal foil in contact with the accessible parts , and (6) between the positive/negative terminal and the accessible non-current carrying conductive parts, etc. Chroma offers a test instrument called Chroma 19032-P that can fulfill all aforementioned electrical safety test items. Different test cards are available to accommodate varying test requirements. For more testing points or complex system testing needs, Chroma 19032-P can also be integrated with automated test systems to deliver an even more comprehensive solution.
All in all, Chroma has developed comprehensive test solutions for EV batteries and charging that can cater to market demand worldwide. These solutions assist customers in conducting automated testing according to various regulations, saving them time and costs. In doing so, Chroma is well-positioned to seize the immense business opportunities in the EV industry.
Visit Chroma for more information: https://www.chromaate.com/
Leo Huang, Chairman of Chroma, said, "Chroma has been established for nearly 40 years. Throughout this time, power electronics testing has always been the most important and successful field for Chroma's development
Photo: Chroma