From April 24th to 26th, the 9th China International Energy Storage Conference, hosted by the Energy Storage Application Branch of the China Chemical and Physical Power Supply Industry Association, was held at the InterContinental Hotel in Hangzhou, Zhejiang Province. At the "Energy Storage Power Station and Technology Application (II) Special Session" on the morning of April 25, Liu Aihua, general manager of Hangzhou Kegong Electronic Technology Co., Ltd., shared the theme report "Key Factors in the Development of Energy Storage Commercialization and the Role of BMS" at the meeting 》, the following is the transcript of the speech: Liu Aihua: Good morning everyone! I am very happy to have such an opportunity to communicate with you today. The PPT I will talk about today will probably focus more on energy storage power stations and commercial operations, including BMS, from these three aspects. The content includes five aspects, the first one is commercialization. In order to develop energy storage power stations, the first Energy Storage Conference was held in 2010. Until today, it has been an upward curve. The real development of the industry still depends on commercial operation. Today I will focus on some things about commercialization. Our company has done some cases in the field of commercialization. The second is how to build a commercial energy storage power station. The third one is the technology and product introduction of Kegong Electronics. The fourth is how to use ladder batteries in commercial energy storage. In the last two minutes, I would like to share the 1.3GWh case done by Kegong. To vigorously develop, there may be three factors, policy, technology and cost. Ultimately it’s about return on investment. In fact, many people are talking about whether energy storage needs subsidies. Personally, I don’t think there is any need for subsidies. Just like electric vehicles, including early photovoltaics, sooner or later you have to return to the basics after you reach a certain level. The second is system technology, which consists of three major components: PCS, battery, BMS and EMS. The third piece is system efficiency. When an energy storage power station is to be truly commercialized, efficiency is very critical and is directly related to functions, including system costs. The rest is the entire subsequent system maintenance. In addition to building a website, it is more important for a website to run for ten or even fifteen years. In this process, how do you make a website run for ten or even fifteen years? The longest I have ever done has been eight or nine years. The first core of the commercial development of energy storage systems is that the system must be safe and reliable. Especially after the State Grid invested in some power stations last year, everyone paid more and more attention to the key factors of safety and reliability. Including Jiangsu energy storage power stations, which have done the most. I have participated in at least five security meetings, all focusing on safety regulations, security strategies, and the angles from which the entire system is safe, including fire protection. Firefighting meetings were discussed at least four times. The second factor is low cost. Often people will look for bias and ignore safety as soon as they focus on low cost. How to reduce costs while ensuring a safe system. This is a summary of the sites we are currently working on. The first one is in the area of lead and carbon, such as peak shaving and valley filling. The other one is lithium batteries. These prices are the system prices summarized from the 1.3GWh power station we built. They are relatively close to the current market conditions, including the average price of lithium batteries, which is about 0.85 to 0.9 yuan. Let’s not talk about jobs below the third-tier level. There are jobs below the third-tier job that cost 60 cents, or even 50 cents. Personally, I think such batteries cannot be used in energy storage power stations. I think the 45,560 cents battery is worth considering. From the perspective of these data, whether it is lead-carbon or iron-lithium, I think the current price has reached a value that can be invested. The premise is that this station can run for ten years. There is no need to change the battery in the middle. If you replace the battery during ten years of operation, you will definitely not be able to recoup the cost. The third key factor is how to reduce costs when the prices of batteries and equipment drop to a certain level. This is an issue that everyone must consider when the entire industry develops to a certain point. What to do when there is no way to surrender. The first one is to consider the indicators of the entire system design. Improving its indicators will in turn reduce its costs. And reducing costs is not just a little bit. Reducing equipment costs by ten points is enough. However, if the efficiency of the entire system can be improved to five points, it means that the entire investment cost has dropped. For example, one station costs RMB 4, which means that the investment cost has dropped by 5%. The second system exploits efficiency. Different companies use different batteries, which may be designed with 2100 degrees or 2200 degrees. The extra 100 to 200 degrees is the cost. How to improve availability efficiency. Efficiency is the entire life cycle of an energy storage power station. Instead of running for three months, it can reach 90 or 95 after running for one year. There are now some projects that require operation for 15 years without battery replacement. How much efficiency can be achieved in this case is critical. The second is system efficiency and conversion efficiency. Including PCS and batteries, many experts here are experts in the battery industry or PCS industry. In the case of air conditioning, how much efficiency can be achieved in the south or the Yangtze River Delta? If the efficiency can be improved by three or four points, does it mean that the cost has been reduced by three to four points in disguise? This makes perfect sense. Battery conversion efficiency, PCS efficiency, system integration losses include line losses. Some items measured now are 83% and 84%, but some items can reach 87% and 88%. How to improve these three points is very critical. This needs to be done through some technical means. For example, container interior simulation, how to control the temperature, and how to design the air duct. This is a system problem. These things directly affect the frequency of turning on the air conditioner. According to different regional characteristics, different power stations, such as Xinjiang and Tibet, have low temperatures all year round and cannot exceed 35 degrees. My design may be different. Air conditioning has a characteristic, the cooling effect is great, but the heating effect is not good. The design inside has many technical thresholds. The other one is the efficiency of the entire system. Emphasis on the whole process, even if the efficiency of the entire PCS process is at least 97%. The ultimate goal is to increase the cost of the entire system. In addition, at least so far, I haven’t really seen too many batteries dedicated for energy storage. Most of them are directly moved from the vehicle. Many batteries are used in vehicles, such as passenger cars and smaller buses, which directly use energy to store energy. But cars and energy storage are completely different. There are at least ten differences. The national and industry standards are different, the hierarchical structure is different, the battery parallel capacity is different, the power is ten times different, etc., and the power supply level is also different. Therefore, energy storage requires special batteries, and more emphasis is placed on service life, which should last ten or fifteen years. The energy density should be high and the cycle life should be long, which is about 6,000 times. Under normal circumstances, it can run for ten or fifteen years without any problems. In addition, the charging and discharging efficiency needs to be improved. How many kilowatt hours of electricity can be released after charging one kilowatt hour of electricity. At 0.5C, domestic iron lithium batteries are generally around 91%-96%. The internal structure and internal resistance may be different. Let the data speak for itself. This is a difference of four to five points. We do BMS, and I will focus on what kind of BMS is needed for commercial operation. The first one requires a dedicated BMS for energy storage. All kinds of BMS are now swarming in. Vehicle protection boards dare to be used as energy storage BMS, and 48V communication BMS are also thrown in directly. There is no problem with the function, but the performance is completely different. Various safety guarantees, such as several temperature points, are there every day when these temperatures are abnormal. The protection board is calculated purely by voltage, and many things are completely different. Now some users may have discovered this problem after using it. I have encountered many users who say they need to use a BMS dedicated to energy storage. The second is low-price competition without considering performance. You sell it for 12 cents, I sell it for 10 cents. It is impossible for a business not to make money. Ultimately, there must be a reason why it's priced so low. Either the quantity is extremely large, or some low-cost things are used. Third, there are many BMSs with very large technical indicator errors. The SOC accuracy deviation is huge, there is no SOH parameter, and the voltage and temperature parameters are inaccurate. These things are related. Including many parameters, whether the balance is false balance, wrong balance, or wrong balance. At least at the current stage, there are still many such BMS. Fourth, there are many BMS systems that are insecure, and there are too many BMSs that do not perform protection at critical moments. After so many energy storage power stations were burned in South Korea, everyone is paying more and more attention to the safety of energy storage power stations. Will the BMS itself burn if it is short-circuited? Will it burn if the external power cord is short-circuited? Many materials are not flame retardant. In addition, when the battery information is abnormal, is the alarm timely, is the protection timely, or is it not reported at all? At least I personally think that the burning of many stations is that you have reached the burning limit, but you did not report it, which delayed the best results. Alarm and protection time have a great relationship. Fifth, the system power consumption is too large. There are many technical routes involved. Different BMS technical routes will have very different power consumption, and even make the originally consistent battery inconsistent. This is a fatal thing, and many users don’t know it. So BMS To do it well, you need to do a lot of details, down to the management of each cell's power consumption, temperature rise, voltage, SOC, SOH, the cell's active balancing method, abnormal changes, etc. How to build an energy storage power station that meets commercial requirements? First, the system must be safe and have stable performance. Second, the electromagnetic compatibility of the system should be better. Is it enough to find a third party to do a test? It's definitely not the case. Just take a lab report to various testing institutions? It's far from it. You have to actually use it in an actual energy storage power station. The other one is the investment profit cost per unit Wh. The system cost is less than or equal to 1.36 yuan/wh. According to the current electricity price policy, the cost can be recovered in 5.5 years. Fourth, the system construction period and maintenance costs should be low. This part is very critical in the later stage. This is an electromagnetic compatibility waveform captured at some actual sites. This is relatively normal, but it is very disturbing. In such an environment, how can BMS withstand this interference? I skipped the company introduction and did three businesses. The first one is BMS and on-site monitoring, the second one is echelon battery utilization, and the third one is system integration. By February 2019, we had built 1.3GWh of energy storage power stations, and BYD’s was not included. Not to mention 32 invention patents and other patents, I got the national high-tech enterprise certificate in less than the third year. This is a partner, there are probably more than 50 long-term partners. This is an introduction to the system architecture. We do not need to add any converters, and it supports various protocols (including IEC61850). These are some basic functions that energy storage BMS needs to have. How does the battery change? The other thing is the temperature rise and voltage per unit time. How big the change is and whether it is reflected in time. The second is various abnormalities, which must be found in time. When people use your BMS, if these functions are not available, the BMS will not be of much use. This is a SOC policy, which is more complicated. This is SOH. I found the relevant curve. The premise is that there must be a lot of historical data. This is active balance, which is one of the biggest advantages of Kegong. Active equalization 5 amps max. It is used in many FM stations, and the efficiency reaches 87% and 88%. This is the difference with peers, where is the balanced difference. Skip this, this is our own on-site monitoring. This is our product, also skip it. We have two characteristics. The BMS of lithium batteries and lead-carbon batteries are completely different. I did some analysis on ladder utilization. This is some analysis of secondary batteries. We did tiered utilization relatively early. I have been involved since 2012. Including a relatively large project in the Southern Power Grid, which is the country's largest echelon utilization project. This is our case, there are about 112 energy storage power stations. Those with a few tens of kilowatts are not included in the calculation. Let me talk about some of the more typical ones. Currently, many are being done overseas. Australia, Germany, India, Africa, the United States, Brazil, Thailand, Taiwan, and Germany have produced more than 50 MWh. There will be more countries in the future, but they have not yet been announced. This is in cooperation with Kelu. This is Jiangsu Zhongneng Silicon Industry, which is still running and has been running for more than four years. This is 12MWh of Tibet Nima, at minus 25 degrees Celsius, this project has been running every day for more than 3 years. Ladder utilization is also skipped. This is the 863 project with Nanjing Network. This is the Wuxi Xingzhou 160MWh project, which has been in operation for more than two years. This is FM in India, made in 2016. This was done in 2016 and 2017. This is MCC’s container energy storage project of 160MWh. This is currently a project with the highest technological level in the country, Nanjing Mobile 28.8MWh project. This is Ningxia's 12MWh, skip it. This is 28MWh in Xinjiang, and the BMS is supplied by us. This is a virtual synchronous machine 2C energy storage integration project with NARI, this is a 9MW frequency modulation project in Changzhi, Shanxi, etc. Thanks!

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