With the rapid development of electric vehicles, ensuring safe, stable, and fast charging of electric vehicle batteries has become a key factor in the widespread acceptance of electric vehicles by consumers. One crucial component to ensure the safety of battery charging is the fuse that complies with the specifications of the automotive industry's AEC-Q200. This article will introduce you to the key technologies of electric vehicle charging, along with the characteristics of fuses introduced by SCHURTER that meet the requirements of the AEC-Q200 specification.
Ensuring the safety of a large number of row-parallel connected charging batteries is crucial
Fossil fuels are limited in supply and their combustion releases harmful gases causing air pollution, making electric vehicles an important direction for the future development of the automotive industry. However, in recent decades, the number and size of cars have been increasing, making them more comfortable, robust, and safe, but also heavier. The weight of mid-range cars has reached 1.5 tons. Therefore, electric vehicles also require a large amount of energy to provide sufficient power.
To ensure that electric vehicles have enough power, small battery cells (each cell size is 4 VDC/3200 mAh) need to be interconnected in parallel and in the row. About 100 cells need to be connected in a row to obtain an operating voltage of approximately 400 VDC. Many such 400 V strings in parallel battery packs are then assembled to achieve the durability, range, and performance of the entire battery pack in high-performance electric vehicles. In powerful electric vehicles, thousands of cells will be needed for rapid assembly in this way.
Therefore, ensuring the safety of electric vehicle charging is crucial, involving various safety measures and practices. During the charging process, recognized charging equipment must be used, and the charging equipment must be regularly inspected and maintained. It is important to avoid moisture and extreme environments, correctly insert and disconnect plugs during the charging process, monitor the charging process, follow manufacturer recommendations, prevent overcharging, and avoid physical damage. In electric vehicles, a Battery Management System (BMS) is typically used to ensure the safety of charging and discharging.
The BMS in electric vehicles is a critical electronic system designed to monitor, control, and manage high-voltage lithium-ion batteries in electric vehicles. BMS aims to maximize battery performance, safety, and lifespan. The functions of BMS typically include voltage monitoring, temperature monitoring, charge and discharge management, fault detection and management, capacity estimation, communication, and control. BMS can maximize the performance of the battery while ensuring its safety and long-term lifespan. It allows vehicles to efficiently utilize battery energy and reduces the risk of damage or performance degradation that may occur in the battery.
Battery balancing is a key technology to ensure the safety of the charging process
Given the installation of thousands of such batteries in electric vehicles, the charging process is crucial, and the batteries must be charged in as short a time as possible. The solution to this challenging task is called "battery balancing." This refers to an electronic circuit (often part of the BMS) that ensures even charging of the battery pack's individual cells. Due to manufacturing differences or varying usage conditions, slight electrical characteristic differences may exist among these cells. This can result in some cells charging or discharging faster than others, causing voltage or capacity imbalances. "Battery balancing" is the process of uniformly charging the battery pack.
The primary purpose of battery balancing technology is to ensure that each cell in the entire battery pack can be charged and discharged evenly. This helps avoid issues arising from imbalances, such as capacity and voltage imbalances. The working principle of battery balancing is to slow down the charging of cells that absorb energy very quickly. This is done to balance the weakest link in the - chain sets of battery pack, determining the speed of the charging process. Each battery cell needs individual attention, and this is the only way to utilize the maximum capacity of the battery pack while compensating for the aging/weakening of individual cells.
Of course, each individual cell in the battery pack must be protected against overcurrent. Thousands of fuses are required for each battery pack, depending on its configuration. Given the critical nature of these fuses, they must be entirely reliable. This protection must operate without any faults for at least 15 years. The fuses must function equally well in the coldest winter and hottest summer temperatures, withstand shocks, vibrations, daily grind, and cycles of switching on, switching off, accelerating, etc. The requirements for these fuses are quite stringent.
Battery balancing technology is crucial for extending battery life, improving performance, and ensuring safety. By maintaining balance between individual battery cells, the performance of the entire battery pack can be utilized more effectively, and the risks of battery damage or performance degradation can be reduced.
AEC-Q200 specifies standard requirements for passive components in the automotive industry
AEC stands for the Automotive Electronics Council, an organization based in the United States that focuses on the standardization of the qualification of electronic components in the automotive supply industry. The Q200 standard, introduced in the mid-1990s, outlines requirements for passive components, while the Q100 standard and its derivatives focus on active components. These AEC standards are globally recognized and accepted by all leading manufacturers in the automotive industry.
The development of the AEC-Q200 standard aims to ensure the reliability and durability of automotive electronic components under extreme environmental conditions. The internal environment of automobiles imposes stringent requirements on electronic components, such as high temperatures, low temperatures, vibrations, humidity variations, and more.
The AEC-Q200 standard was first introduced in 2001 and has been continuously revised and updated since then to adapt to evolving technologies and demands. It covers various test conditions and requirements to ensure the reliability of electronic components. The standard specifies various test items, including high-temperature life testing, low-temperature life testing, humidity life testing, humidity temperature cycling testing, humidity constant pressure testing, temperature cycling testing, mechanical vibration testing, etc., to validate the reliability and durability of components under extreme conditions.
Adherence to the AEC-Q200 standard is crucial for manufacturers and suppliers in the automotive electronic supply chain. Components that comply with this standard demonstrate their ability to provide stable and reliable performance in automotive applications. It helps reduce recalls and issues caused by electronic component failures, enhancing the safety and reliability of automotive systems.
While specific tests for fuses used in automobiles were not initially relevant throughout the automotive development history, the evolution of technology and applications in automotive electronics has changed this scenario. With the introduction of electronic control units and power drives, fuses will be included as a topic in the next update of the Q200 standard. The AEC-Q200 standard continues to be updated and refined to ensure its alignment with current and future requirements for automotive electronic components, continuously improving the reliability and safety of automotive systems.
High-quality fuses compliant with AEC-Q200 specifications
SCHURTER has always focused on the high-reliability requirements of the aerospace industry, collaborating with the European Space Agency (ESA) and developing products in accordance with the specifications of other passive components of AEC-Q200. Through close collaboration with major players in the global automotive industry, SCHURTER has developed testing procedures for fuses to meet the requirements of Q200. Fuses manufactured in this way can bear the Q200 "seal of approval," which is unrestricted and internationally recognized.
SCHURTER offers a complete range of fuses compliant with AEC-Q200 standards for the automotive industry, supporting various applications such as battery management, air conditioning, close-coupled electronic devices for diesel and gasoline engines, and more. SCHURTER's close connections with international automotive organizations and the industry itself make it highly capable of addressing all issues related to electronic equipment protection in vehicle manufacturing.
As a constant innovator and manufacturer of global electronic and electrical components, SCHURTER ensures safe, clean power supply while making equipment easy to use. SCHURTER provides a wide range of standard products, including circuit protection, connectors, EMC products, switches and input systems, as well as electronic manufacturing services. Additionally, SCHURTER is ready to collaborate with customers to meet their application-specific requirements.
Taking the SCHURTER UMT 250 series fuse as an example, it is a surface-mount (SMD) fuse with dimensions of only 3 x 10.1 mm, supporting 250 VAC and 125 VDC, and it is an SMD fuse that operates in the range of 80 mA to 10 A. The fuse is designed with a compact form factor to minimize footprints while maximizing its breaking capacity. It is suitable for pulse-shaped continuous currents.
The UMT 250 series operates in a high current range from 80 mA to 10 A, supporting a high breaking capacity of 200 A @ 250 VAC (IEC). It is UL approval for 277 VAC and 250 VDC, and, according to ATEx and IECEx requirements, it can be used for hermetically sealed potting, ideal for intrinsically safe applications, including primary protection of SMD PCBs, medical equipment, battery protection, and other application areas.
Conclusion
The safe charging and discharging of batteries in electric vehicles are critical factors that cannot be overlooked. Fuses compliant with the AEC-Q200 standard are essential components to ensure the safety of the battery charging process in electric vehicles. SCHURTER offers a complete range of fuses that meet the AEC-Q200 standard, providing a reliable choice for various safety requirements in electric vehicle applications. Choosing SCHURTER's fuses will be an ideal component selection for developing related products in the automotive industry.