LR44 battery.Innovative application of lithium-ion battery energy storage technology in Pengshanling Tunnel

　　Tunnel power costs account for more than 50% of daily mechanical and electrical maintenance costs. On the premise of ensuring tunnel driving safety, studying measures that can be taken to reduce tunnel power costs has good economic prospects. The Pengshanling Tunnel builds an energy storage system that can take advantage of peak and valley electricity prices.

　　Tunnel power costs account for more than 50% of daily mechanical and electrical maintenance costs. On the premise of ensuring tunnel driving safety, studying measures that can be taken to reduce tunnel power costs has good economic prospects. The Pengshanling Tunnel construction energy storage system can not only obtain economic benefits by utilizing the peak-valley electricity price difference, but also can replace the traditional tunnel UPS power supply system as a backup power supply for the tunnel. Its function and stability are further upgraded compared to UPS power supply, which can enhance the stability of tunnel power supply. .

　　Driven by innovation, build a cost-reducing and efficiency-increasing energy storage system

　　The energy storage system has the characteristics of peak shaving and valley filling, delayed power consumption, and power quality optimization. Peak shaving and valley filling means charging when the power is in the "flat" and "valley" periods, and discharging the power in the "peak" period. By smoothing the user load curve It can reduce the power subscription amount during the "peak" period, reduce the need to purchase electric energy at a relatively high price, and reduce the total electricity bill. When the power grid occasionally loses power, the energy storage system can serve as a backup power source to continuously provide power to users. In addition, the installation and application of energy storage systems can filter out disturbances from the power grid and can be used as a special power quality control device to improve the power supply quality of important loads. From the perspective of energy conservation and emission reduction, the energy storage system transfers electric energy from low-carbon emission power sources during non-peak load periods to peak load periods, thereby reducing the consumption of high-emission energy and conducive to energy conservation and emission reduction.

　　The second step is to explore the operation and management of green energy-saving tunnels.

　　Low temperature lithium iron phosphate battery 3.2V 20A -20℃ charging, -40℃ 3C discharge capacity ≥70%

　　Charging temperature: -20~45℃ -Discharge temperature: -40~+55℃ -40℃ Support maximum discharge rate: 3C -40℃ 3C discharge capacity retention rate ≥70%

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　　Based on the on-site tunnel investigation and recording of real-time power consumption data, and after statistical analysis of the power load of the Pengshanling Tunnel, this project selected a 50kW converter and a 150kWh battery pack, and equipped an EMS controller to control the battery charge and discharge time and charge and discharge Power is scheduled to form an energy storage control system. By calculating the power load of the tunnel, the transformer has remaining capacity that can be utilized. Without changing the original power distribution system lines of the tunnel, the energy storage system is incorporated into the tunnel power distribution system through the spare drawer cabinet reserved in the tunnel. The project began with research, method design, equipment purchase, equipment installation and commissioning in October 2018, and the construction was completed on January 18, 2019. During the construction period, the tunnel was carried out without power outage, and the tunnel still had normal power supply.

　　Three economic benefits

　　In terms of power costs. Taking the Pengshanling Tunnel as an example, according to statistics, charging in 30 days is about 12,390KWh, discharging is about 11,750KWh, the total income in 30 days is about 4,560 yuan, and the average daily income is 152 yuan. Based on this calculation, the 10-year operation of the Pengshanling Tunnel Energy Storage System will save about 500,000 yuan in electricity bills.

　　Low temperature and high energy density 18650 3350mAh-40℃ 0.5C discharge capacity ≥60%

　　Charging temperature: 0~45℃ Discharge temperature: -40~+55℃ Specific energy: 240Wh/kg -40℃ Discharge capacity retention rate: 0.5C Discharge capacity ≥ 60%

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　　Investment in emergency lighting equipment. After the system is put into operation, it can replace one 50KVAUPS unit, saving a total of about 200,000 yuan in equipment purchase and maintenance costs.

　　Deducting the investment cost of purchasing and installing energy storage system equipment of approximately 400,000 yuan, the Pengshanling Tunnel lithium-ion battery energy storage project will earn approximately 300,000 yuan in the next 10 years. If our company deploys this system in all tunnels, the economic benefits in the next 10 years are expected Up to 20 million yuan.