Will fast charging and overcharging damage the battery?
Author: Huyan panliang source: jinyang.com
Recently, Mr. Zhong, a new car owner in Guangzhou, told the Yangcheng Evening News that he was worried that fast charging and overcharging would seriously damage the battery life and would only choose slow charging in the future. The reporter visited the market and found that many car owners have such concerns. In addition, there are rumors in the market that "the new car needs to run out of electricity before charging".
Clarifying the facts and cracking the rumors are beneficial to improving the consumption quality, optimizing the consumption environment and boosting the production development of relevant enterprises. In addition, in view of the sustainable development of new energy vehicle batteries, charging piles and other aspects, at the two sessions of the National People's Congress this year, deputies to the National People's Congress and members of the Chinese people's Political Consultative Conference in the automotive industry made suggestions on how to help the high-quality development of the new energy vehicle industry from the perspective of "electricity".
Should the new car be fully charged for the first time
"A new car needs to use up electricity before charging, from zero to 100". In the new energy vehicle consumption market, rumors like this still exist. This rumor can be traced back to the era of non smart phones.
At that time, mobile phones used nickel chromium batteries or nickel hydrogen rechargeable batteries. Consumers were used to using up the battery before charging it for the first time. At that time, it was widely said that such batteries had a certain "memory effect". If the mobile phone was charged when the electricity was not used up, the contents of the battery would crystallize, making the battery "mistakenly think" that there was no electricity. In the long run, the battery capacity would be reduced until it could not store electricity at all.
Up to now, the batteries used in new energy vehicles are all chemical batteries, including lead acid, lithium titanate, lithium cobalt oxide, lithium iron phosphate, nickel cobalt manganese and nickel cobalt aluminum. No matter the common electronic equipment or new energy vehicles, lithium-ion batteries are the mainstream choice at this stage. Lithium compounds are used as electrode materials and graphite as anode materials.
According to the wechat official account of the Institute of physics of the Chinese Academy of Sciences, among all commercially available batteries, lithium-ion batteries have the highest energy density (electric energy stored per unit volume) and specific energy (electric energy stored per unit mass). At the same time, lithium-ion batteries have a long cycle life. The cycle life of excellent ternary material batteries can reach more than 3000 times, and lithium iron phosphate batteries can reach tens of thousands of times, which can last for 8 years and 27 years respectively if charged once a day. In addition, lithium-ion batteries have the advantages of light weight, less pollution and no "memory effect". In other words, new energy vehicles using such batteries do not need to use up the electricity before charging.
At present, new energy vehicles can travel about 100 to 200 kilometers with full primary electric energy and can be recharged in a day to a week. According to some 4S store clerks, the first charge can be fully charged, and it is better to start charging when the power is about 20%. The most important thing is that shallow charging and shallow discharging are safer. Pay attention to avoid overcharging, over discharging and under charging, and judge whether it can be charged according to the color of the charger indicator light. Therefore, it is generally recommended that consumers choose daytime charging in order to control the charging time.
Will fast charging and overcharging battery definitely lose life
With the continuous improvement of the production, sales and ownership of new energy vehicles, the high ratio of cars to piles leads to "difficulty in waiting for piles" and "difficulty in finding one pile" during holidays. Driven by "charging anxiety", the era of overcharge of new energy vehicles is coming. China is accelerating the construction of charging and replacing facilities. The number of charging piles in China will increase by nearly 100% year-on-year in 2022. Followed by another heavy anxiety: fast charging and overcharging will lead to battery life loss.
The so-called slow charge refers to AC charging, which generally takes 6 to 8 hours to fully charge the battery. Fast charge and overcharge refer to high-power DC charging, which can be charged to 80% or more in half an hour or less. Generally, charging rate exceeding 1C is considered as fast charging. 1C refers to the full capacity of a battery. 1C charging means that the battery will be fully charged in 1 hour.
Thermal management and BMS (battery management system) are closely related to battery health.
The book "Research Report on automotive big data application (2021)" mentioned that nine common factors affecting battery health include: current battery capacity, battery internal resistance, charge and discharge depth, charge and discharge rate, self discharge rate, overcharge and over discharge, cycle times, charge and discharge current and temperature. Among them, in terms of charge and discharge rate, when charging at high rate, the temperature of the battery may rise too fast, which adds difficulty to the thermal management and leads to the deterioration of battery health.
BMS is known as the "protector" of the battery, which can detect and analyze the battery status, avoid over discharge, and extend the service life of the battery.
Using safe and reliable thermal management system, BMS, etc., can effectively protect battery health. For example, the annual report of 2021 shows that Ningde times has owned and is applying for a total of 10222 patents at home and abroad, including modules, BMS, thermal management, thermal safety and other battery systems. In November 2022, the patent of "vehicle thermal management system and vehicle" applied by Ningde times was authorized, which can adjust the temperature of the battery and improve the endurance. By using the products and services provided by such large manufacturers and developing good charging habits, the battery loss caused by normal fast charging and overcharging can be relatively ignored.
Boost the battery industry to open up the charging "blocking point"
China is the world's largest new energy vehicle market. Power battery is considered to be the core of new energy vehicles and the key link of the industrial chain. The rapid growth of charging infrastructure effectively supports the rapid development of new energy vehicles. Next, how to continue to promote the healthy development of the power battery industry and optimize the charging network layout is an important proposition to be solved.
In recent years, the domestic battery energy storage industry has grown rapidly, but the products are mixed.
Zeng Yuqun, member of the National Committee of the Chinese people's Political Consultative Conference and chairman of Ningde times, suggested to speed up the research on the "passport" and supporting policies of power batteries, and pointed out that the battery energy storage needs nuclear power level security. According to his vision, "battery passport" is the digital twin of physical battery, which can realize transparent digital management of the whole supply chain of power battery. Consumers and regulators can simply and directly access the relevant information of battery products through the "battery passport", which can provide a data base for battery carbon footprint, recycling and traceability, and echelon utilization.
Zhuhuarong, deputy to the National People's Congress, Secretary of the Party committee and chairman of Chang'an Automobile, suggested promoting the standardization of power batteries for new energy vehicles and accelerating the development and layout of mineral resources such as lithium resources.
At the same time, China has built the world's largest and most widely distributed charging infrastructure network. According to the data of China charging alliance, about 54000 public charging piles were added in 2022. By the end of September 2022, Guangdong Province has 345126 public charging piles and 19116 charging stations.
The demand for DC charging piles is also very strong. Among the public charging piles, AC charging piles are still the mainstream, but DC fast charging is expected to accelerate its development. According to the 2021 white paper on charging behavior of Chinese electric vehicle users released by China charging alliance, DC charging piles have become the first choice for 99.3% of users.
Pan Helin, CO director and researcher of the digital economy and financial innovation research center of the International Business School of Zhejiang University, is optimistic about the future development of overcharge. Comparing power exchange with charging, he told Yangcheng Evening News that power exchange is more suitable for public rental transportation, but in the field of private cars, power exchange is not suitable, and the application scenarios are not wide enough. Therefore, overcharge is the main development direction for a long time in the future.
However, the "uneven hot and cold" and "charging anxiety" of public charging stations around the country are still widespread.
Liu Yong, deputy to the National People's Congress, director, general manager and Deputy Secretary of the Party committee of State Grid Jiangxi Electric Power Co., Ltd., suggested that we should speed up the improvement of the infrastructure construction planning for new energy vehicles, and integrate the construction of charging facilities into the overall consideration and scientific layout of urban and rural construction planning.
Zhangzutao, deputy to the National People's Congress, director of the engineering training center of southwestjiaotonguniversity and executive director of the College of innovation and entrepreneurship, suggested sorting out "zombie piles", releasing the station and power capacity, and charging app uniformly.
Reproduced in http://www.batterychn.com/newinfo-1003-2
