Patent Number: 
Section: claims

1. Method to provide emergency power supply to nuclear power plant, comprising:providing accumulator battery system, said accumulator battery system is connected to emergency bus and monitored by online monitoring system, wherein the online monitoring system is configured to:collect performance parameters of batteries in the accumulator battery system, and calculate the total capacity of the accumulator battery system, wherein the accumulator battery system comprises a plurality of accumulator system modules in parallel connection, said plurality of accumulator system modules are connected to the emergency bus via bus rod, the accumulator system module comprises converter device and battery array, said battery array is connected to the bus rod via the converter device, a first switch control unit is disposed between the accumulator system module and the bus rod, the online monitoring system control the accumulator system module to put into operation via controlling the first switch control unit according to the load capacity under current working conditions,monitor working conditions of the nuclear power plant, calculate load capacity of the nuclear power plant under current working conditions, in case of power loss of the electrical devices of the nuclear power plant, start the accumulator battery system to provide power supply to the electrical devices of the nuclear power plant via the emergency bus according to the total capacity of the accumulator battery system and the load capacity of the nuclear power plant under current working conditions;in case of power loss of electrical devices of the nuclear power plant, the online monitoring system starts the accumulator battery system to provide power supply to the electrical devices of the nuclear power plant via the emergency bus. 2. The method of claim 1, wherein the battery array comprises a plurality of battery modules, said plurality of battery modules are in parallel connection with the converter device, the battery module comprises a plurality single batteries in serial and/or parallel connection, a second switch control unit is dispose between the battery modules and the converter device, the online monitoring system determines whether the battery modules are faulty or not according to the performance parameters of the batteries in the accumulator battery system, the online monitoring system isolates faulty battery modules and puts backup battery modules into operation. 3. The method of claim 1, wherein during battery testing or maintaining, an accumulator system module is controlled to charge another accumulator system module. 4. The method of claim 1, wherein the online monitoring system is configured toput a first accumulator system module in the accumulator battery system into operation;put a second accumulator system module in the accumulator battery system into operation, and perform in loop until all accumulator system modules are put into operation or the accumulator battery system meets corresponding power supply requirements. 5. The method of claim 1, wherein the online monitoring system is configured to: send isolated island starting command to the accumulator battery system to enter isolated island mode, control the accumulator battery system to provide power supply to the loss of power devices of the nuclear power plant, wherein steps of controlling the accumulator battery system to provide power supply to the loss of power devices comprise: controlling the accumulator battery system to drive Hydrotest Pump Turbine Generator Set and control system of the accumulator battery system itself to work normally; controlling the accumulator battery system to drive auxiliary water supply system to work normally; When external power grid is retrieved and voltage of grid side of parallel breaker is inspected to be normal and last for a predetermined time, disconnecting the outlet breaker of the accumulator battery system and entering non-isolated island operation mode. 6. The method of claim 1, wherein further providing portable accumulator battery system, switching on at least one portable accumulator battery system in case that the total capacity of the accumulator battery system is not enough for the load capacity under current working conditions. 7. System to provide emergency power supply to nuclear power plant, used to provide emergency power supply to electrical devices of nuclear power plant, comprising:accumulator battery system, online monitoring system electrically connected to the accumulator battery system, the accumulator battery system is connected to the electrical devices of the nuclear power plant via emergency bus, wherein the accumulator battery system comprises a plurality of accumulator system modules, the plurality of accumulator system modules are connected to the emergency bus in parallel connection via bus rod, the accumulator system module comprises converter device and battery array, the converter device is connected to the bus rod, the battery array is connected to the converter device, the battery array comprises DC bus and battery modules, the battery modules are in parallel connection with the DC bus, the DC bus is connected to the converter device; the battery module comprises a plurality of single batteries in serial and/or parallel connection, a second switch control unit is disposed between the battery module and converter device, controlled by the online monitoring system; a first switch control unit is disposed between the accumulator system module and the bus rod, controlled by the online monitoring system;the online monitoring system is configured to collect performance parameters of batteries in the accumulator battery system, calculate total capacity of the accumulator battery system, monitor working conditions of the nuclear power plant, calculate load capacity of the nuclear power plant under current working conditions, in case of power loss of the electrical devices of the nuclear power plant, start the accumulator battery system to provide power supply to the electrical devices of the nuclear power plant via the emergency bus according to the total capacity of the accumulator battery system and the load capacity of the nuclear power plant under current working conditions. 8. The system of claim 7, wherein the accumulator system module further comprises battery module monitor to monitor state of each battery module in real time, the battery module includes a plurality of battery packs in serial and/or parallel connection, the battery pack includes a plurality of single batteries in serial connection; each single battery is arranged in rows or columns, flexible pad or at least two vertical flexible strips are disposed between each single battery, positive pole and negative pole of each two adjacent batteries are in flexible electrical connection, the single battery is provided with temperature collection components and voltage collection components inside, the temperature collection components and voltage collection components are configured to send the collected temperature and voltage of the single battery to signal aggregation module of the battery pack, the signal aggregation module is connected to the battery module monitor via data transmission line. 9. The system of claim 8, wherein the plurality of battery packs are fixed to battery cabin or inside battery rack, the battery cabin or battery rack is provided with a plurality parallel bulkheads to form a plurality of battery compartments accommodating the plurality of battery packs, the signal aggregation module is disposed in the battery compartment, wiring compartment is disposed vertically at the side end of the battery cabin or battery rack, the battery module monitor is disposed on the cabin body or rack body, the battery pack is disposed inside a shell, then mounted in the battery compartment; the shell is provided with elastic piece in flexible contact with the outside of the battery pack on inner wall, the shell is also provided with an end cap used to compress and fix the single batteries inside the shell tightly. 10. The system of claim 8, wherein the plurality of battery packs are fixed inside a battery cabin or battery rack, the battery cabin or rack is provide with a plurality of parallel bulkheads to form battery compartment accommodating the plurality of battery packs, the signal aggregation module is disposed in the battery compartment, wiring compartment is disposed vertically at the side end of the battery cabin or battery rack, the battery module monitor is disposed on the cabin body or rack body, the battery pack with the single batteries being arranged is disposed on battery basket with an opening at one end, then mounted on the battery compartment; the battery basket is provided with elastic piece in flexible contact with the outside of the battery pack, the battery basket is provided with second connection piece used to connect the fastening strips for fastening the single batteries arranged in the battery basket. 11. The system of claim 9, wherein the system to provide emergency power supply to nuclear power plant is disposed in a storage device, said storage device is waterproof, shockproof and temperature adjustable, the storage device is disposed on a reference platform, comprising an shockproof accommodating cavity fixed to the reference platform, cavity to accommodate the battery cabin or battery rack, converter device and monitoring and control devices are disposed in the accommodating cavity, the storage location of the converter device and monitoring and control devices are higher than the storage location of the battery cabin or battery rack, the cavity to accommodate the battery cabin or battery rack has a plurality of bases used to mount and fix the battery cabin or battery rack, each of the bases is higher than the cavity ground. 12. system of claim 11, wherein the cavity to accommodate the battery cabin or battery rack is provided with water pit at the bottom, drainage equipment used to drain the accommodating cavity is disposed in the water pit, nozzles used to spray water in case of fire are disposed on the top of the cavity accommodating the battery cabin or battery rack, each of the nozzles is disposed on a water pipe connected to the water pit, the water pipe is also connected to a water tank dispose outside the accommodating cavity, the water pipe is provide with water pump and control valve. 13. The system of claim 10, wherein the system to provide emergency power supply to nuclear power plant is disposed in a storage device, said storage device is waterproof, shockproof and temperature adjustable, the storage device is disposed on a reference platform, comprising an shockproof accommodating cavity fixed to the reference platform, cavity to accommodate the battery cabin or battery rack, converter device and monitoring and control devices are disposed in the accommodating cavity, the storage location of the converter device and monitoring and control devices are higher than the storage location of the battery cabin or battery rack, the cavity to accommodate the battery cabin or battery rack has a plurality of bases used to mount and fix the battery cabin or battery rack, each of the bases is higher than the cavity ground.