Energy storage system based on lithium iron phosphate battery

Abstract

The invention discloses an energy storage system based on a lithium iron phosphate battery, and relates to the technical field of energy storage systems, the energy storage system comprises a container, a battery cabinet is arranged in the container, the battery cabinet is connected with a confluence cabinet, the confluence cabinet is connected with a control cabinet, the confluence cabinet is further connected with a heat management system, and the control cabinet is connected with the heat management system. The thermal management system is connected to the battery cabinet, and the control cabinet is further connected with a fire extinguishing system which is connected to the battery cabinet. High space intensification is achieved, transportation, installation and maintenance are convenient, the service life and reliability of the battery pack are ensured, and the lithium iron phosphate battery boxes are adopted, so that the advantages of high safety, long service life, high energy density and the like are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage systems, and in particular to an energy storage system based on a lithium iron phosphate battery. Background Art

[0002] In the context of the profound changes in the global energy landscape, the contradiction between the continued growth of energy demand and the pressure on traditional energy supply has become increasingly prominent. With the rapid development of renewable energy, such as wind power and solar energy, its intermittency and instability have brought great challenges to the stable operation of the power system. In order to solve this problem, energy storage systems, as an effective solution, have become increasingly important in the power system.

[0003] With its unique advantages, lithium iron phosphate batteries have gradually become an ideal choice for energy storage systems. On the one hand, lithium iron phosphate batteries are highly safe and can effectively reduce the risk of safety accidents in various complex use environments. Compared with other types of batteries, their chemical properties are relatively stable and are not prone to dangerous situations such as overheating, combustion, or even explosion. On the other hand, the battery has high reliability and can maintain stable performance during long-term use. Whether under frequent charging and discharging conditions or under different temperature and humidity conditions, it can operate reliably, providing a solid guarantee for the stable operation of the energy storage system.

[0004] At the same time, lithium iron phosphate batteries also have the characteristics of high energy density. This means that at the same volume or weight, it can store more energy, providing more powerful energy storage support for various application scenarios. In addition, its long cycle life is also a major advantage. After multiple charge and discharge cycles, it can still maintain a high capacity and performance, reducing the maintenance cost and replacement frequency of the system, making the energy storage system based on lithium iron phosphate batteries have higher economic benefits and practical value in long-term operation.

[0005] In traditional energy storage systems, the performance consistency of battery packs is often difficult to ensure, which may cause some batteries to fail prematurely, affecting the performance and life of the entire system. There may also be inefficiencies in energy storage and deployment, as well as the risk of battery overheating, combustion, or even explosion.

[0006] Therefore, an energy storage system based on lithium iron phosphate batteries is proposed. Summary of the invention

[0007] The purpose of the present invention is to provide an energy storage system based on lithium iron phosphate batteries, which has high battery performance, precise temperature control, high energy storage, and high system integration to overcome the shortcomings of the prior art battery packs that are often difficult to ensure performance consistency and have a low system life.

[0008] In order to achieve the above object, the present invention provides the following technical solutions: A lithium iron phosphate battery-based energy storage system includes a container, which provides a closed and safe space, facilitates overall transportation and installation, and protects internal equipment from external environmental influences; a battery cabinet is arranged inside the container, which is used to install and accommodate lithium iron phosphate battery boxes and provide structural support and electrical connections; the battery cabinet is connected to a junction cabinet, which converges the currents of multiple battery cabinets to achieve centralized management and distribution of current; the junction cabinet is connected to a control cabinet, which is also connected to a thermal management system, which is connected to a thermal management system, which maintains the battery operating within an appropriate temperature range and improves battery performance and life; the thermal management system is connected to the battery cabinet, which is also connected to a fire protection system, which is connected to the battery cabinet, and when a fire occurs, the fire protection system promptly detects and extinguishes the fire and issues an alarm to ensure system safety; the thermal management system is connected to the fire protection system.

[0009] Furthermore, the battery cabinet is provided with a lithium iron phosphate battery box. The lithium iron phosphate battery has the advantages of high safety and long life. The 19 lithium iron phosphate battery boxes are connected in series with a main control box and an isolating switch box, and the main control box is connected to the isolating switch box. The 19 lithium iron phosphate battery boxes increase the system voltage to meet different power requirements; the main control box can monitor and manage the battery to ensure safe and efficient operation of the battery; the isolating switch box can isolate the battery from the system when necessary, which is convenient for maintenance and repair.

[0010] Furthermore, the lithium iron phosphate battery box has 20 cells connected in series, and the voltage of the lithium iron phosphate battery box is 64V after the 20 cells are connected in series.

[0011] Furthermore, the thermal management system includes a temperature sensor, the temperature sensor is connected to a controller, the controller is connected to an air conditioner, and the air conditioner is connected to an air duct. The real-time monitoring of the temperature in the container provides temperature data to the controller, and the controller can control the operating state of the air conditioner according to the data of the temperature sensor to maintain the temperature in the container within a suitable range; the supercooling or heating function adjusts the temperature in the container; the air duct guides the air flow so that the cold (hot) air generated by the air conditioner is evenly distributed to various parts of the container.

[0012] Furthermore, the inner wall of the air duct is covered with heat-insulating cotton with a thickness of not less than 10 mm and made of rubber-plastic sponge, so as to reduce heat loss or external heat input, improve heat management efficiency, and ensure stable temperature in the container.

[0013] Furthermore, the air conditioner is an integrated air conditioner, a ceiling-mounted air conditioner, or a wall-mounted air conditioner. A variety of air conditioners can meet different installation requirements.

[0014] Furthermore, an S-shaped louver is added to the condensation air inlet outside the air conditioner box to prevent debris from entering the air conditioner, ensure the normal operation of the air conditioner, and at the same time play a certain rain protection role; a rain cover is added to the air outlet to prevent rainwater from entering the air conditioner and avoid equipment damage caused by rainwater.

[0015] Furthermore, the fire protection system includes a fire detector, the fire detector is connected to a fire controller, and the fire controller is connected to a fire extinguishing device and an alarm device.

[0016] Furthermore, the temperature in the container is 23±5°C, ensuring that the battery operates at a suitable temperature, improving battery performance and life; the temperature difference of the battery cells is less than 3°C, and the temperature of each battery cell is uniform, avoiding battery performance degradation and shortening of life due to excessive temperature difference. Furthermore, the energy storage system adopts four-level balancing management to ensure the consistency of the battery during operation.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides an energy storage system based on lithium iron phosphate batteries, which integrates battery cabinets, junction cabinets, control cabinets, thermal management systems and fire protection systems in a container, achieving a high degree of space intensiveness and facilitating transportation, installation and maintenance. This integrated design reduces the equipment footprint and improves space utilization, and is particularly suitable for application scenarios with limited space. A thermal management system is provided, which has good heat dissipation management and high-strength structural design to ensure the life and reliability of the battery pack; the thermal management system and the fire protection system work together, and when the thermal management system detects an abnormal increase in battery temperature, it may send an early warning signal to the fire protection system to alert the fire protection system to potential fire risks.

[0018] Specifically, the battery cabinet uses lithium iron phosphate battery boxes, which have the advantages of high safety, long life and high energy density. The 19 battery boxes are connected in series to the main control box and the isolation switch box, realizing effective battery management and safety control.

[0019] Specifically, the thermal management system of this system can control the temperature inside the container at 23±5℃ through the coordinated work of temperature sensors, controllers and air conditioners, making the temperature difference of the battery cells less than 3℃, ensuring that the battery operates within an appropriate temperature range, and improving the safety and stability of the system.

[0020] Specifically, the system realizes effective management of battery charging and discharging and reasonable allocation of energy through the coordinated work of battery cabinets, junction cabinets and control cabinets, thereby improving the energy storage and allocation efficiency of the system.

[0021] Specifically, in order to ensure the consistency of battery performance during operation, a four-level balancing management method is used to ensure the available capacity and service life of the energy storage system. Battery and system monitoring software is used to achieve automatic operation of the energy storage system. This avoids the possibility of premature failure of some batteries, affecting the performance and life of the entire system, and possible inefficiencies in energy storage and deployment, and avoids the risk of battery overheating, combustion, or even explosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The figure is an overall schematic diagram of an energy storage system based on a lithium iron phosphate battery in an embodiment of the present invention.

[0023] Figure 2 Schematic diagram of a thermal management system of an energy storage system based on a lithium iron phosphate battery in an embodiment of the present invention.

[0024] Figure 3 Schematic diagram of a fire protection system of an energy storage system based on a lithium iron phosphate battery in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0026] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0027] See also Figure 1, a lithium iron phosphate battery-based energy storage system, first, a sturdy container is placed in a suitable position, which provides a closed and safe space for the entire energy storage system. The existence of the container not only facilitates the overall transportation and installation of the system, but also effectively protects the internal equipment from external environmental factors such as wind, rain, dust and impact; a battery cabinet is arranged inside the container, and a lithium iron phosphate battery box is arranged inside the battery cabinet. The 19 lithium iron phosphate battery boxes are connected in series with a main control box and an isolating switch box, and the main control box is connected to the isolating switch box, so as to achieve effective battery management and safety control; the junction cabinet is connected to a control cabinet, and the junction cabinet is used for current junction distribution; the junction cabinet is also connected to a thermal management system, and the control cabinet is connected to a thermal management system, and the thermal management system is connected to the battery cabinet, and the control cabinet is also connected to a fire protection system, and the fire protection system is connected to the battery cabinet. Because the battery generates heat during operation, if the heat is not dissipated in time or the heat dissipation consistency is poor, it will cause heat accumulation or excessive temperature difference of the battery cell, affecting the safety of battery operation and accelerating the battery capacity decay. When the energy storage system is in a low temperature environment, the low temperature will reduce the power and capacity of charging and discharging. Therefore, it is necessary to perform thermal management design on the energy storage system; the thermal management system is connected to the fire protection system.

[0028] In some preferred embodiments of the present invention, the battery cabinet is connected to a junction cabinet, the junction cabinet is connected to a control cabinet, the junction cabinet is also connected to a thermal management system, the control cabinet is connected to a thermal management system, the thermal management system is connected to the battery cabinet, the control cabinet is also connected to a fire protection system, the fire protection system is connected to the battery cabinet; the fire protection system can ensure the safe operation of the energy storage system. The battery cabinet adopts a grouped and layered design, the cabinet appearance adopts maintenance-free technology, and uses materials with good corrosion resistance to reduce the maintenance workload of the cabinet appearance and extend the maintenance cycle; 19 lithium iron phosphate battery boxes and 1 main control box are installed inside the battery cabinet.

[0029] In some preferred embodiments of the present invention, the 19 lithium iron phosphate battery boxes inside the battery cabinet are connected to the junction cabinet through cables. The function of the junction cabinet is to converge and distribute the current of multiple battery cabinets to ensure the stable transmission of current. The junction cabinet can monitor and control the current to ensure the safe operation of the entire energy storage system. The lithium iron phosphate battery box is connected in series with 20 battery cells. After the 20 battery cells are connected in series, the voltage of the lithium iron phosphate battery box is 64V, which ensures the stable output power of the system. At the same time, strictly controlling the temperature difference of the battery cells to be less than 3°C is conducive to extending the battery life and improving the consistency and reliability of battery performance.

[0030] In some preferred embodiments of the present invention, the energy storage system adopts four-level balancing management to ensure the consistency of the battery during operation, which is specifically the following processing: Level 1 balancing achieves balancing of the cell S0C (cell state of charge) through passive balancing. When SOC<30% or S0C>90% at the end of charge and discharge, the passive balancing condition is turned on, the S0C deviation at the end of charge and discharge is>5%, and the condition S0C<3% is turned off. The maximum balancing current is 200mA, and the maximum balancing speed is 200mAh / hour. The value of the balancing current can be changed by controlling the duty cycle. Balancing is performed throughout the entire charge and discharge process, which prolongs the balancing time and improves the balancing effect.

[0031] Secondary balancing uses partial cluster operation mode to achieve intelligent switching of clusters with high (low) SOC, and maintains partial cluster operation mode to achieve SOC balance among clusters.

[0032] The three-level balancing realizes SOC balancing of multiple clusters or energy storage sub-units through the local controller.

[0033] Four-level balancing reasonably distributes the discharge power of each battery cluster according to the SOC and health status of each battery cluster, while taking into account the internal balance to ensure that the system runs efficiently and stably while extending the battery life as much as possible.

[0034] The use of battery balancing control strategy can effectively ensure the available capacity and service life of the energy storage system; the use of battery and system monitoring software can realize the automatic operation of the energy storage system.

[0035] Example 2 Based on Example 1, the battery generates heat during operation. If the heat is not dissipated in time or the heat dissipation consistency is poor, it will cause heat accumulation or excessive temperature difference in the battery cell, thereby affecting the battery operation safety and accelerating the battery capacity decay. When the energy storage system is in a low temperature environment, the low temperature will reduce the power and capacity of charging and discharging, so it is necessary to perform thermal management design on the energy storage system.

[0036] First, the heat load of the container and the battery are calculated, and the heat generated during operation under different operating scenarios is calculated, which mainly includes the heat leakage caused by the temperature difference between the inside and outside of the container, and the radiant heat caused by factors such as solar radiation, container installation angle, and surface spray color. Secondly, the cooling capacity must be sufficient to transfer the system heat load outside the container; the air volume must meet the heat dissipation requirements of the battery module; the wind pressure must meet the air outlet of the air conditioner to send cold air to the remote end; the operating temperature range must meet the extreme temperature of the project site (when it is high, the cooling capacity of the air conditioner decreases. When it is low, the air conditioner starts up); the air conditioning form needs to be selected according to the layout of equipment in the container such as batteries, and the layout of energy storage containers such as stacking and firewalls. The form of air conditioning can be divided into integrated air conditioning, roof-mounted air conditioning, and wall-mounted air conditioning according to the structure, which meets different installation requirements and space restrictions and improves the adaptability of the system. The integrated air conditioner is suitable for all battery types and is easy to install. Transportation and maintenance, and the air duct design is relatively convenient.

[0037] Finally, the built-in industrial air conditioner is only a medium for heat exchange, and needs to be matched with a special air duct to evenly deliver the hot or cold air generated by the air conditioner to each battery, thereby improving the heat dissipation efficiency of the temperature control system and the consistency of battery heat dissipation. The air duct is the air flow channel from the air outlet of the air conditioner to the battery and then to the return air outlet of the air conditioner. According to the position of the air outlet of the air conditioner, it can generally be divided into top duct, bottom duct and side duct.

[0038] The thermal management system includes a temperature sensor, which is connected to a controller, which is connected to an air conditioner, which is connected to an air duct; the temperature sensor can monitor the temperature changes in the container in real time and transmit the data to the controller. The controller accurately controls the operation of the air conditioner according to the temperature conditions. When the battery temperature is high, the air conditioner operates in the cooling mode, and the heat generated by the battery operation is transferred to the outside of the container to ensure the safety, reliability and excellent performance of the system; when the battery temperature is low, the air conditioner operates in the heating mode, and the temperature of the battery is raised to the required operating temperature of the battery cell to ensure the normal operation of the system at low temperatures. The temperature in the container is controlled at 23±5℃, so that the lithium battery operates at the optimal operating temperature, avoiding the risks of low temperature capacity reduction, high temperature battery rapid attenuation and thermal runaway. The temperature difference of the battery cells in the battery module is less than 3℃, which makes the battery charge and discharge consistency good, suppresses the "barrel effect" and avoids the risk of parallel circulation of battery clusters.

[0039] When the air outlet temperature of the air conditioner is low and the humidity in the container is high, condensation is easy to occur in the air duct, which can easily damage electrical equipment. Therefore, the inner wall of the air duct is covered with thermal insulation cotton with a thickness of not less than 10mm and made of rubber-plastic sponge, which effectively reduces heat loss and the influence of external temperature and improves the efficiency of the thermal management system. S-shaped shutters are added to the condensation air inlet outside the air conditioner box and rain covers are added to the air outlet, which can prevent debris from entering and adapt to various adverse weather conditions, ensuring the stable operation of the air conditioner.

[0040] In some embodiments of the present invention, the fire protection system includes a fire detector, the fire detector is connected to a fire controller, and the fire controller is connected to a fire extinguishing device and an alarm device. The fire detector can detect fire hazards in time and transmit signals to the fire controller. The fire controller quickly activates the fire extinguishing device and the alarm device, achieving rapid response and fire extinguishing, and effectively ensuring the safety of personnel and equipment.

[0041] In actual application, considering the convenience of equipment operation and maintenance, a single-layer container layout is adopted. The container is planned to have doors on both the front and rear sides, one side is a double-opening working door, and the other side is a single-opening escape door. The distance between adjacent containers in a row is considered to be 2.5m; a circular road is set up in the container area for equipment installation and maintenance. The overall layout is compact and orderly, and the space is fully utilized.

[0042] The energy storage system based on lithium iron phosphate battery provided by the present invention realizes efficient energy storage and output through the coordinated work of various parts, while ensuring the safety and reliability of the system. The suitable temperature in the container and the small temperature difference of the battery cells extend the service life of the battery and reduce the maintenance cost. The effective operation of the thermal management system and the fire protection system improves the stability and safety of the system and provides users with a reliable energy storage solution.

[0043] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0044] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. An energy storage system based on lithium iron phosphate battery, characterized in that: It includes a container, wherein a battery cabinet is arranged inside the container, the battery cabinet is connected to a junction cabinet, the junction cabinet is connected to a control cabinet, the junction cabinet is also connected to a thermal management system, the control cabinet is connected to the thermal management system, the thermal management system is connected to the battery cabinet, the control cabinet is also connected to a fire protection system, the fire protection system is connected to the battery cabinet, and the thermal management system is connected to the fire protection system.

2. The energy storage system based on lithium iron phosphate battery according to claim 1, characterized in that: The battery cabinet is provided with a lithium iron phosphate battery box, and the 19 lithium iron phosphate battery boxes are connected in series with a main control box and an isolating switch box, and the main control box is connected to the isolating switch box.

3. The energy storage system based on lithium iron phosphate battery according to claim 2, characterized in that: The lithium iron phosphate battery box is connected in series with 20 cells, and the voltage of the lithium iron phosphate battery box is 64V after the 20 cells are connected in series.

4. The energy storage system based on lithium iron phosphate battery according to claim 1, characterized in that: The thermal management system includes a temperature sensor, the temperature sensor is connected to a controller, the controller is connected to an air conditioner, and the air conditioner is connected to an air duct.

5. The energy storage system based on lithium iron phosphate battery according to claim 4, characterized in that: The inner wall of the air duct is pasted with thermal insulation cotton with a thickness of not less than 10 mm and is made of rubber-plastic sponge.

6. The energy storage system based on lithium iron phosphate battery according to claim 4, characterized in that: The air conditioner can be an integrated air conditioner, a ceiling-mounted air conditioner or a wall-mounted air conditioner.

7. The energy storage system based on lithium iron phosphate battery according to claim 6, characterized in that: An S-shaped louver is added to the condensation air inlet outside the air conditioning box, and a rain cover is added to the air outlet.

8. The energy storage system based on lithium iron phosphate battery according to claim 1, characterized in that: The fire protection system comprises a fire detector, the fire detector is connected to a fire controller, and the fire controller is connected to a fire extinguishing device and an alarm device.

9. The energy storage system based on lithium iron phosphate battery according to claim 1, characterized in that: The temperature in the container is 23±5°C, and the temperature difference of the battery cells is less than 3°C.

10. The energy storage system based on lithium iron phosphate battery according to claim 1, characterized in that: The energy storage system adopts four-level balancing management to ensure the consistency of the battery during operation.

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