High-precision and high-reliability RTC, helping BMS safety management of new energy vehicles
In recent years, driven by the rapid development of emerging technologies such as the Internet of Things, artificial intelligence, and new energy, the automobile industry has undergone unprecedented changes. According to statistics, with the continuous improvement of automobile intelligence, the sales volume of automobile complaints has shown a step-by-step growth trend since 2017, and the accompanying safety hazards have also emerged one after another. According to statistics, there will be about 3,000 new energy vehicle fire accidents nationwide in 2021. The increase in the failure rate of automobiles, especially the increase in the spontaneous combustion of new energy vehicles, makes us have to re-examine automobile safety issues in the era of intelligence. As one of the core functions of new energy electric vehicles, BMS (Battery Management System) also plays a particularly important role in the safety of new energy vehicles.
New energy vehicle BMS
As people pay more and more attention to the battery life and battery safety of new energy vehicles, the function of BMS has also been redefined.
Battery, motor and electronic control technology are the core technologies of new energy vehicles, and the core function of electronic control is BMS (Battery Management System), that is, battery management system. As a pillar behind intelligent driving, BMS protects the safe use of electric vehicle power batteries. BMS is a system that monitors and manages batteries. By collecting and calculating parameters such as voltage, current, temperature, and SOC (state of charge), it controls the charging and discharging process of the battery to protect the battery and improve the overall performance of the battery. The management system also records important logs in real time, which can be uploaded to the monitoring center through the Internet of Vehicles to monitor and manage vehicles in real time, and can also investigate and locate problems and optimize product design in the later stage. All of these are inseparable from a high-precision and high-reliability RTC chip to improve the accurate timestamp for the BMS log. The role of RTC in BMS:
System architecture diagram of BMS
As one of the wake-up sources, trigger the BMS to perform self-check management on its own working mode (sleep, running...);As a condition of the SOC algorithm, it is used to periodically correct the SOC; the calendar time provides the BMS with the time coordinates (timestamp) corresponding to historical data and fault information.
1. Timing wake-up "physical examination" BMS controller needs real-time clock circuit for timing reminder. When the set time is reached, RTC will output an alarm wake-up signal (INT interrupt signal) to wake up the controller to perform self-checking actions.2. A condition of the SOC algorithm. After the SOC correction system is powered on regularly, the total battery voltage is read, and then an initial power value is determined. Although there is a certain error, this value can basically be used to participate in the following ampere hours. Integral operation. However, in special scenarios, for example, the battery has not been left to stand for more than 2 hours, and the system restarts due to some problem during high-power discharge. At this time, there will be a problem with the open-circuit voltage method to determine the power. In order to solve this problem, it is necessary to design an external independent RTC to record the SOC and related information in real time. After the system is started, read the SOC log in the flash, and then judge whether the time when it is stored has passed 2 hours, so as to determine whether it uses the open circuit voltage method to determine the initial SOC, or directly uses the SOC value stored in the FLASH as the initial SOC.
3. Calendar time, providing BMS with historical data and time coordinates (timestamps) corresponding to fault information. BMS will record important logs in real time according to the time provided by RTC, which can be uploaded to the monitoring center through the Internet of Vehicles to monitor and manage vehicles in real time , you can also investigate and locate the problem and optimize the design of the product in the later stage. Dapu Communication has launched a series of high-precision, high-reliability integrated RTCs, which provide reliable time stamping and timing functions for the stable operation of the BMS system, and help users to perform fault analysis and risk management of battery packs.
Dapu RTC features:1. Built-in crystal, reduce the number of components in the design scheme, improve the efficiency of PCB layout, and reduce the system failure rate.
2. High precision: ±3.4ppm/±5ppm/±20ppm@-40℃~+85℃, providing accurate timestamps for logs to help customers locate problems accurately.
3. Low power consumption: as low as 0.5uA, improve battery life.
4. Support backup battery switching, cope with main power failure, and further improve system reliability.
5. Ultra-small package: 3.2*2.5*1.0mm, suitable for system miniaturization and high-density design, free from the constraints of traditional solutions.
With the rapid development of technology, great changes are taking place in every field, and the market puts forward more stringent requirements for the functional definition, high reliability and more challenges of core chips/devices. Dapu Communication RTC products adhere to the high-precision and high-reliability technology as the main line, and gradually realize product serialization according to the needs of the industry and customers.
Typical application block diagram of Dapu RTC
So far, 8 major categories and more than 15 single item numbers have been developed, covering a wide range of fields such as communications, automobiles, electric power, medical care, and industrial control. In the future, Dapu will continue to focus on in-depth research and innovation, and strive to meet the diversified needs of the market.
As an authorized agent of Dapu Communication, WTL can provide you with a full range of Dapu products to your clients, including RTC product series. Feel free to contact us if you have any questions or concerns at any time.
