A mobile shelter power station and a control method thereof

Abstract

The application discloses a mobile square cabin power station and a control method thereof, and belongs to the technical field of energy storage. The mobile square cabin power station comprises a box body, a battery pack, an electrical system, an energy control system EMS, a battery management system BMS and a thermal management system. The battery pack comprises lithium titanate battery clusters a, lithium iron phosphate battery clusters a, lithium titanate battery clusters b and lithium iron phosphate battery clusters b. The lithium titanate battery clusters a, the lithium iron phosphate battery clusters a, the lithium titanate battery clusters b and the lithium iron phosphate battery clusters b are respectively formed into independent loops and are connected in parallel to a direct-current bus of the electrical system. The battery pack is composed of lithium iron phosphate batteries and lithium titanate batteries, and the two kinds of batteries are used in cooperation, so that the technical requirements can be met and the cost can be controlled. The application solves the problem that the existing mobile square cabin power station powered by lithium ion batteries cannot realize normal-temperature fast charging and direct starting and running in an ultralow-temperature environment, and the system has good practicability and high reliability, and is suitable for mobile energy storage power supply in an extremely cold environment in a special field.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, specifically to a mobile modular power station and its control method. Background Technology

[0002] At present, mobile modular power stations are widely used in the field of large-scale energy storage, mainly large diesel vehicle power stations. They have disadvantages such as poor environmental adaptability, large size, heavy weight, poor power quality, and the need for frequent maintenance. Compared with traditional diesel vehicle power stations, mobile modular power stations powered by lithium-ion batteries have many advantages such as cleanliness and environmental protection, high power quality, strong endurance, high power supply reliability, and flexible operation. They are gradually emerging and being put into use. In response to the load demand under different working conditions, mobile modular power stations should achieve the following technical effects: (1) fast charging at room temperature, with a charging amount of not less than 60% of the rated capacity in 30 minutes; (2) normal charging, direct start-up, and operation at rated power in extremely cold environments of -40℃; (3) low cost and high reliability.

[0003] Existing mobile energy storage units powered by lithium-ion batteries mainly use lithium iron phosphate batteries, ternary lithium batteries, and lithium titanate batteries. Among them, ternary lithium batteries pose a risk of fire and explosion under some extreme conditions. Inexpensive lithium iron phosphate batteries have slightly poor low-temperature performance; long-term low-temperature charging and discharging can severely affect battery capacity and cycle life, and the charging current is no higher than 1C. Lithium titanate batteries have good low-temperature performance and can reach charging currents of 10C or even higher, but they are more expensive, have lower energy density, and are significantly limited in space. For example, Chinese patent CN202110991883.7 discloses a topology-reconfigurable energy storage system, a mobile energy storage unit, and its diverse application methods. Topology reconfiguration allows the energy storage unit to be adapted to different application scenarios. However, this patent uses lithium iron phosphate batteries with poor low-temperature performance, therefore it cannot achieve the technical effects of rapid charging at room temperature and direct start-up and operation in ultra-low temperature environments. Utility Model Content

[0004] The purpose of this invention is to provide a mobile modular power station and its control method to solve the problem that existing high-power mobile modular power stations powered by lithium-ion batteries cannot achieve fast charging at room temperature and direct start-up and operation at rated power in ultra-low temperature environments.

[0005] This invention is achieved using the following technical solution:

[0006] The mobile modular power station includes a housing, battery packs, an electrical system, an energy control system (EMS), a battery management system (BMS), and a thermal management system. The battery pack comprises lithium titanate battery clusters a, lithium iron phosphate battery clusters a, b, and b. Each of these clusters forms an independent circuit connected in parallel to the DC bus of the electrical system. The EMS, BMS, and thermal management system directly or indirectly communicate and control the battery packs and electrical system, enabling charging and discharging of the mobile modular power station. The thermal management system provides intelligent heating for the lithium iron phosphate battery clusters operating in low or ultra-low temperature environments. The battery pack consists of lithium iron phosphate (LFP) batteries and lithium titanate (LTI) batteries. The total energy of each LTI cluster is 0.3 times that of each LFP cluster. The charging current of each LTI cluster and each LFP cluster is set to 2C-3C and 0.95C-1C, respectively. The LFP batteries have a discharge temperature of -25℃ to 55℃ and a charging temperature of 0℃ to 55℃. The LTI batteries can meet a 10C charging current at room temperature and can be charged and discharged normally at -40℃. The combination of the two types of batteries fully utilizes their respective advantages and avoids their disadvantages, which can meet technical requirements and control costs. To address the differences in voltage platforms, battery systems, and discharge curves between lithium iron phosphate (LFP) and lithium titanate (LiTi) batteries, a multi-level management approach is adopted for the two types of batteries. Specifically, batteries are grouped according to their battery systems, and multiple groups of different battery voltages are directly connected in parallel to the DC bus after being converted to the same numerical platform to form a unified battery system. To further ensure reliable system operation, two branches are set up for each type of battery, with each branch forming a cluster. Four battery clusters run in parallel, and the voltage platforms and capacities of the battery clusters can be the same or different. The energy control system (EMS) controls the DC-DC bidirectional converter to achieve joint or independent energy output of the battery clusters. Therefore, the system will not suddenly collapse when one of the battery clusters fails.

[0007] Furthermore, the interior of the enclosure is divided into two independent battery compartments and an electrical compartment, separated by a firewall. The electrical compartment is connected to an external DC charging station and an AC power plug. The battery compartment is enclosed, and the external DC charging station and AC power plug connected to the electrical compartment can supply power to the power station. The enclosure is lined with 30mm to 100mm thick rock wool purification panels, which provide insulation, fire resistance, moisture protection, and sound absorption.

[0008] Furthermore, the Energy Control System (EMS) communicates with the Electrical System, Battery Management System (BMS), external DC charging station, and AC power plug. The EMS regulates the operating status of each component by sending communication commands, communicating with the BMS via LAN; specifically, the EMS interacts with the Electrical System's bidirectional DC-DC converter, bidirectional PCS, and AC-DC converter.

[0009] Furthermore, the lithium iron phosphate battery cluster a is equipped with a PTC heater a, and the lithium iron phosphate battery cluster b is equipped with a PTC heater b. When the system operating environment is at low or even ultra-low temperatures, the lithium iron phosphate battery clusters can be heated by using PTC heaters to raise their temperature to a suitable level for normal operation.

[0010] Furthermore, the electrical system includes a PDU execution unit PDUa, and a fuse a is connected in series between the PDUa and the positive terminal of the lithium titanate battery cluster a. The other three battery clusters are connected to their respective PDU execution units and fuses in the same way. When a fault occurs, the fuse melts to break the circuit, thereby preventing the battery clusters from short-circuiting.

[0011] The electrical system is equipped with a bidirectional DC-DCa, and a manual maintenance switch b is connected in series between the bidirectional DC-DCa and PDUa. The other three PDU execution units are connected to their respective bidirectional DC-DC and manual maintenance switches in the same way. The manual maintenance switch can ensure the safety of maintenance and other operations on the battery pack side.

[0012] The electrical system is equipped with two DC charging sockets, DC charging socket a and DC charging socket b; the two DC charging sockets can work simultaneously or independently, and when working simultaneously, they can achieve DC fast charging.

[0013] The DC bus of the electrical system is connected to the bidirectional PCS via a manual maintenance switch a and then divided into three branches; the three branches respectively satisfy DC discharge, AC charging and AC discharge.

[0014] The electrical system includes relays KMa and KMb, which are interlocked under high voltage. Relays KMa and KMb form a logically related control circuit through high voltage interlock, enabling automatic switching of relay states under different charging and discharging modes of the system.

[0015] The electrical system includes a PCS monitoring unit, and the control power supply used by the PCS monitoring unit and the battery management system (BMS) is configured with dual redundant power supplies. One control power supply comes from lithium titanate battery cluster a, and the other comes from lithium iron phosphate battery cluster b.

[0016] Furthermore, the Battery Management System (BMS) is a three-tier architecture, including an antenna, a Human-Machine Interface (HMI), a first-level column management unit (BAU), and subordinate second-level battery cluster management units (BPUs) and third-level battery module management units (BMUs). The antenna can transmit remotely monitored system operation information to the backend via LAN. The HMI enables human-machine interaction for system operation, and communicates with the column management units (BAUs) via RS485. The column management units (BAUs) communicate with the battery cluster management units (BPUs) to monitor and schedule each battery cluster in real time. There are four battery cluster management units (BPUs), each managing its corresponding battery cluster. They are responsible for data communication with the battery module management units (BMUs) within their respective clusters, collecting operational information of the entire cluster, alarming and protecting against abnormalities in the battery pack, and performing battery balancing strategy analysis, SOC calculation, insulation detection, relay adhesion detection, and controlling relevant relays. The number of battery module management units (BMUs) is matched to the number of battery cluster management units (BPUs). They are responsible for collecting real-time information such as voltage and temperature of the battery modules, and performing automatic charge / discharge bidirectional balancing management, online detection, and fault diagnosis.

[0017] Furthermore, the electrical system includes a DC fast charging branch, a DC discharging branch, an AC charging branch, and an AC discharging branch.

[0018] The DC fast charging branch includes: the DC bus is connected to DC charging socket a and DC charging socket b after passing through relay KMd.

[0019] The DC discharge branch includes: a bidirectional PCS connected to an ACDC via a relay KMc, the other end of the ACDC connected to the DC output main line, and the required DC output interface connected to the DC output main line.

[0020] The AC charging branch includes: a bidirectional PCS connected to the AC charging dock via a relay KMa;

[0021] The AC discharge branch includes: a bidirectional PCS connected to the AC output interface via a relay KMb.

[0022] The mobile modular power station control method described above can realize DC fast charging, DC discharging, AC charging, and AC discharging. The relationship between the steps of DC fast charging, DC discharging, AC charging, and AC discharging is as follows:

[0023] S1: Connect to an external DC charging station to enable DC fast charging;

[0024] S2: DC fast charging is off; when connected to an external DC load, DC discharge is on.

[0025] S3: DC discharge off; connect an external AC power plug to start AC charging.

[0026] S4: AC charging is off. When an external AC load is connected, AC discharge is enabled.

[0027] Furthermore, the specific steps of the DC fast charging and DC discharging processes are as follows:

[0028] S1-1: DC charging base a and DC charging base b are respectively connected to external DC charging piles; the mobile modular power station connects to external DC charging piles for DC charging. When the two DC charging bases work at the same time, DC fast charging can be achieved.

[0029] S1-2: The Energy Control System (EMS) communicates with the external DC charging pile and the Column Management Unit (BAU) of the Battery Management System (BMS); the Energy Control System (EMS) communicates with the external DC charging pile to determine charging, and obtains the status and charging parameters of each battery cluster through the Column Management Unit (BAU).

[0030] S1-3: The Energy Control System (EMS) sends a closing signal to the relay KMd and simultaneously adjusts the four bidirectional DC-DC converters. The EMS adjusts the bidirectional DC-DCa, bidirectional DC-DCb, bidirectional DC-DCc, and bidirectional DC-DCd according to the charging parameters of each battery cluster provided by the Column Management Unit (BAU) to meet the charging requirements of each battery cluster.

[0031] S1-4: The column management unit (BAU) sends a charging signal to the PDU execution unit connected to each battery cluster; the PDU execution unit can provide safe and stable power distribution to the four battery clusters.

[0032] S1-5: Open the charging circuit to perform DC fast charging; the energy on the DC bus is distributed to each battery cluster according to the status of the four bidirectional DC-DC converters.

[0033] S2-1: The DC voltage on the four battery clusters is adjusted to the same voltage platform through their respective bidirectional DC-DC converters, and the energy is concentrated on the DC bus.

[0034] S2-2: The DC power on the DC bus is converted into three-phase AC power after passing through the bidirectional PCS DC terminal;

[0035] S2-3: When relay KMc is closed, the three-phase AC power enters one end of the ACDC after passing through relay KMc. The three-phase AC power is converted into the required DC power inside the ACDC.

[0036] S2-4: The required DC power reaches the DC output main line through the other end of the ACDC converter; the required DC output interface is connected to the DC output main line.

[0037] S2-5: DC power is output to an external DC load through the DC output interface for DC discharge.

[0038] Furthermore, the specific steps of the AC charging and AC discharging processes are as follows:

[0039] S3-1: The AC charging dock is connected to an external AC power plug;

[0040] S3-2: The Energy Control System (EMS) enters charging mode;

[0041] S3-3: Relay KMa closes automatically, and relays KMb, KMc, and KMd open automatically;

[0042] S3-4: After passing through relay KMa, the AC power enters the bidirectional PCS AC terminal, where it is converted into DC power and enters the DC bus. After the AC power is converted into DC power and enters the DC bus, it immediately undergoes the same charging process as DC fast charging.

[0043] S3-5: Interactive communication between the Energy Control System (EMS) and the Battery Management System (BMS) Column Management Unit (BAU);

[0044] S3-6: The energy control system EMS sends a closing signal to the relay KMd and simultaneously adjusts the four bidirectional DC-DC converters;

[0045] S3-7: The column management unit (BAU) sends a charging signal to the PDU execution unit connected to each battery cluster;

[0046] S3-8: Open the charging circuit to begin AC charging;

[0047] S4-1: AC output interface is connected to an external AC load;

[0048] S4-2: Relays KMa and KMd are open, while relays KMb and KMc are closed;

[0049] S4-3: The DC power on the DC bus enters the bidirectional PCS DC terminal and is converted into three-phase AC power.

[0050] S4-4: Three-phase AC power reaches the AC output interface after passing through relay KMb;

[0051] S4-5: Three-phase AC power output to external AC loads for AC discharge.

[0052] Compared with the prior art, the beneficial effects of the present invention are:

[0053] (1) The mobile modular power station described in this invention achieves rapid charging at room temperature and direct start-up and operation at rated power in ultra-low temperature environments by using a battery pack composed of lithium iron phosphate batteries and lithium titanate batteries. Furthermore, the parallel operation of four battery clusters enhances the system's reliability. Compared to traditional mobile power stations powered solely by lithium iron phosphate or lithium titanate batteries, this invention can provide power or supply more current to external loads in lower temperature environments with the same energy or cost consumption.

[0054] (2) The mobile modular power station described in this invention is further equipped with an intelligent thermal management system, which can heat the lithium iron phosphate battery cluster in the ultra-low temperature environment to a suitable working temperature through PTC heating, thereby saving system costs, and realizes all-round communication with the help of the energy control system EMS.

[0055] (3) The mobile modular power station control method described in this invention can realize DC fast charging, DC discharge, AC charging and AC discharge, so that the appropriate DC or AC charging and discharging mode can be flexibly selected according to the working environment and charging and discharging requirements during use. It is practical and easy to operate. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the internal structure of the present invention;

[0057] Figure 2 This is a schematic diagram showing the connection relationship between the battery pack and the electrical system of the present invention;

[0058] Figure 3 This is a system topology diagram of the battery management system (BMS) of this invention;

[0059] Figure 4 This is a flowchart illustrating the process of a battery cluster malfunction under the control strategy of this invention.

[0060] Figure 5 This is a flowchart of the battery cluster charging process under the thermal management system of this invention;

[0061] Figure 6 This is a flowchart of the battery cluster discharge process under the thermal management system of this invention; Detailed Implementation

[0062] The English terms and some combined English-Chinese phrases appearing in the description of this invention are explained as follows: 1. PTC heating: PTC electric heater; 2. PCS monitoring unit: Energy storage converter status monitoring unit; 3. AC charging dock: AC charging dock; 4. AC output interface: AC output interface; 5. DC charging dock: DC charging dock; 6. ACDC: Power converter, which converts AC power into stable DC power through rectification and filtering circuit; 7. Bidirectional PCS: Bidirectional energy storage converter, which controls the charging and discharging process of the battery and performs AC-DC conversion; 8. Bidirectional DC-DC: Bidirectional converter, which realizes bidirectional flow of DC power; 9. PDU execution unit / PDU: Power distribution unit, which provides safe and stable power distribution.

[0063] To clearly illustrate the solution in this invention, further explanation is provided below with reference to the accompanying drawings:

[0064] Please refer to Figures 1 to 3 The present invention discloses a mobile modular power station, comprising a housing, a battery pack, an electrical system, an energy control system (EMS1), a battery management system (BMS), and a thermal management system. The housing is lined with 30mm-100mm thick rock wool purification panels. The interior of the housing is divided into a battery compartment and an electrical compartment by partition walls. The electrical compartment is connected to an external DC charging pile and AC power plug.

[0065] The battery pack includes lithium titanate battery cluster a44, lithium iron phosphate battery cluster a47, lithium titanate battery cluster b50, and lithium iron phosphate battery cluster b52. The independent circuits formed by the lithium titanate battery cluster a44, lithium iron phosphate battery cluster a47, lithium titanate battery cluster b50, and lithium iron phosphate battery cluster b52 are respectively connected in parallel to the DC bus 18 of the electrical system.

[0066] The electrical system consists of seven parts: PCS monitoring unit 3, DC bus 18, DC fast charging branch, DC discharging branch, AC charging branch, AC discharging branch, and other electrical components. The specific connection method is as follows:

[0067] DC fast charging branch: DC bus 18 is connected to DC charging socket a11 and DC charging socket b12 after passing through relay d16.

[0068] DC discharge branch: Bidirectional PCS15 is connected to ACDC14 via relay KMc13. The other end of ACDC14 is connected to DC output main line 10. The required DC output interface is connected to DC output main line 10.

[0069] AC charging branch: The bidirectional PCS15 is connected to the AC charging socket 6 via relay KMa7;

[0070] AC discharge branch: Bidirectional PCS15 is connected to AC output interface 9 via relay KMb8;

[0071] Other electrical components include: fuse a35, connected in series between the positive terminal of lithium titanate battery cluster a44 and PDUa28; and three fuses and three PDU execution units connected in series with their respective battery clusters in the same manner, including fuses b38, c39, d40, and PDUs b30, c32, and d34; bidirectional DC-DC a19, one end of which is directly connected to DC bus 18 and the other end to PDUa28; and three bidirectional DC-DC converters connected in the same manner to DC bus 18 and their respective PDU execution units, including bidirectional DC-DC b20, c21, and d22; manual maintenance switch b23 connected in series between PDUa28 and DC-DC a19; and three manual maintenance switches connected in the same manner between the corresponding PDU execution units and the bidirectional DC-DC converters, including manual maintenance switches c24, d25, and e26. And a manual maintenance switch a17 connected in series between DC bus 18 and bidirectional PCS15; a wire led out from the positive terminal of lithium titanate battery cluster a44 passes through manual start switch a36, and the lead wire is connected to the positive terminal of unidirectional DC-DC a37 after passing through manual start switch a36. The positive terminal of the other side of unidirectional DC-DC a37 is connected in series with a diode a45 through a wire and serves as the positive terminal of control power supply line 55. Diode a45 can ensure unidirectional current operation. The negative terminal of lithium titanate battery cluster a44 is directly connected to the negative terminal of unidirectional DC-DC a37. The negative terminal of the other side of unidirectional DC-DC a37 serves as the negative terminal of control power supply line 55. The lead wire in the above connection method is one of the power supply lines of the control power used by battery management system BMS and PCS monitoring unit 3. The other power supply line adopts the same connection method and involves lithium iron phosphate battery cluster b52, fuse d40, manual start switch b41, unidirectional DC-DC b42, diode b54 and control power supply line 55.

[0072] The battery management system (BMS) includes an antenna 2, a human-machine interface (HMI) 5, a column management unit (BAU) 4, and subordinate secondary battery cluster management units (BPUs) and tertiary battery module management units (BMUs). Each battery cluster is configured with one battery cluster management unit (BPU), specifically: BPU1a27 manages lithium titanate battery cluster a44, BPUb29 manages lithium iron phosphate battery cluster a47, BPUc31 manages lithium titanate battery cluster b50, and BPUd33 manages lithium iron phosphate battery cluster b52. Each module within each battery cluster is configured with one battery module management unit (BMU), specifically: the modules in lithium titanate battery cluster a44 correspond to BMUa combination 43, the modules in lithium iron phosphate battery cluster a47 correspond to BMUb combination 46, the modules in lithium titanate battery cluster b50 correspond to BMUc combination 49, and the modules in lithium iron phosphate battery cluster b52 correspond to BMUd combination 51.

[0073] The energy control system EMS1 communicates with four bidirectional DC-DC converters, bidirectional PCS15, AC-DC converter14, battery management system (BMS), external DC charging pile, and AC power plug. It controls the working status of each component by sending communication commands. Communication with the battery management system (BMS) is achieved through LAN.

[0074] The thermal management system is a heating system that only manages the thermal performance of lithium iron phosphate battery clusters. Specifically, lithium iron phosphate battery cluster a47 is equipped with a PTC heater a48, and the heating power is distributed by the PDU execution unit PDUa28. Lithium iron phosphate battery cluster b52 is equipped with a PTC heater b53, and the heating power is distributed by the PDU execution unit PDUc32.

[0075] The connection method and working principle between the battery pack and the electrical system and some components inside the electrical system are as follows: (1) A fuse a35 is connected in series between the PDU execution unit PDUa and the positive electrode of the lithium titanate battery cluster a47. The other three battery clusters are connected to their respective PDU execution units and fuses in the same way. The PDU execution unit can provide a safe and stable power distribution to the battery cluster during charging. The fuse acts as a current protector in the circuit. When a fault occurs, the fuse melts to break the circuit, thereby preventing the battery cluster from short-circuiting. (2) A manual maintenance switch b23 is connected in series between the bidirectional DC-DC a19 and PDUa28. The other three PDU execution units are connected to their respective bidirectional DC-DC and manual maintenance switches in the same way. The bidirectional DC-DC, as a bidirectional converter, can realize bidirectional flow of DC power and has the function of step-up and step-down bidirectional conversion. The manual maintenance switch can ensure the safety of maintenance and upkeep operations on one side of the battery cluster. (3) DC bus 18 is connected to DC charging socket a11 and DC charging socket b12; the two DC charging sockets can work independently or simultaneously, and when working simultaneously, they can meet the requirements of DC fast charging. (4) Manual maintenance switch a17 is connected to bidirectional PCS15 and then divided into three branches; the three branches are DC discharge branch, AC charging branch and AC discharge branch, which can meet DC discharge, AC charging and AC discharge respectively. (5) Relay KMa7 and relay KMb8 are in a high-voltage interlock relationship; through high-voltage interlock, a control circuit with mutual logical relationship is formed, which can realize the automatic switching of relay state under different charging and discharging modes of the system. (6) The control power supply used by PCS monitoring unit 3 and battery management system BMS is a dual-power redundant configuration; the dual-power redundant configuration can ensure the stability and reliability of the power supply, one of which is from lithium titanate battery cluster a47 and the other is from lithium iron phosphate battery cluster b52.

[0076] The working process of this invention embodiment is as follows:

[0077] When the system is in different operating, maintenance, or charging / discharging states, please refer to Table 1 for the states of each switch and four relays under different system states. The specific correspondence is as follows: When the system is not under maintenance, all five manual maintenance switches remain closed; when the system needs to run, two manual start switches are closed simultaneously; when the system is idle, the manual start switches are opened to prevent energy loss; when the system is not charging / discharging, manual start switches a36 and b41 are open, and all four relays are in the open state; when not charging, relays KMa7 and KMd16 remain open, while relays KMb8 and KMc13 automatically turn to the closed state; when the system is discharging, the states of the above four relays remain unchanged; when the system is charging, relays KMa7 and KMd16 turn to the closed state, while relays KMb8 and KMc13 turn to the open state.

[0078] Table 1: Status of switches and relays under different system conditions

[0079]

[0080] Please refer to Figure 4 The four battery clusters are managed by four BPU modules of the Battery Management System (BMS). When a battery cluster fails, the system automatically executes a control strategy: During the operation of the mobile modular power station, the four BMUs continuously collect real-time information of the corresponding battery clusters and perform fault diagnosis. The four BPUs collect operational information of their respective battery clusters through communication with the corresponding BMUs. When a battery cluster experiences a serious fault, the faulty battery cluster's BPU disconnects its charging and discharging circuit and sends battery-related information to the Column Management Unit (BAU4). The Column Management Unit (BAU4) then sends a derating charging and discharging request to the Energy Management System (EMS1). The EMS1 responds quickly, controlling the input and output of the bidirectional PCS15 or the bidirectional DC-DC converter corresponding to the faulty battery cluster to meet the system's short-term or derating requirements. After the faulty battery cluster is cleared, it automatically rejoins the system through the corresponding bidirectional DC-DC converter, thus restoring normal operation. In this process, when a battery cluster fails, the control strategy effectively prevents the faulty battery cluster from becoming unusable or affecting the overall normal operation of the system, thereby improving system reliability.

[0081] Please refer to Figures 5 to 6The thermal management system is a PTC heating system, and the heating process is automatically controlled by the battery management system (BMS). Thermal management is only performed on the lithium iron phosphate (LFP) battery clusters. When the mobile modular power station is in a low-temperature or ultra-low-temperature working environment, the system automatically operates the following thermal management strategy: During charging, when the ambient temperature is above 0°C, both the lithium titanate (LTI) and LFP battery clusters are charged simultaneously. When the temperature is between -40°C and 0°C, the LTI battery clusters are directly charged, and the heating function is activated. An external power source is used to heat the LFP battery clusters via PTC heating. When the ambient temperature rises above 0°C, the LFP battery clusters can begin charging. During discharging, in ambient temperatures below -25°C, only the LTI batteries provide power. The current provided by the LTI batteries is used for external power supply and heating of the LFP batteries. Each LTI battery cluster provides power to one LFP battery cluster. Once the LFP batteries reach a suitable discharge temperature, they are used together for external power output. During the above-mentioned operation, when the system operates in a low-temperature or ultra-low-temperature environment, the lithium iron phosphate battery can be heated by the thermal management system to restore it to normal operating condition and then charge and discharge together with the more expensive lithium titanate battery, thereby effectively reducing the cost of the system.

[0082] The mobile modular power station can perform DC fast charging, DC discharging, AC charging, and AC discharging. The steps of DC fast charging, DC discharging, AC charging, and AC discharging are related as follows:

[0083] S1: Connect to an external DC charging station to enable DC fast charging;

[0084] S2: DC fast charging is off; when connected to an external DC load, DC discharge is on.

[0085] S3: DC discharge off; connect an external AC power plug to start AC charging.

[0086] S4: AC charging is off. When an external AC load is connected, AC discharge is enabled.

[0087] The specific steps for DC fast charging and DC discharging are as follows:

[0088] S1-1: DC charging base a11 and DC charging base b12 are respectively connected to external DC charging piles; the mobile modular power station connects to external DC charging piles for DC charging. When the two DC charging bases work at the same time, DC fast charging can be performed, thereby meeting the fast charging requirements under specific circumstances.

[0089] S1-2: The energy control system EMS1 communicates with the external DC charging pile and the column management unit BAU4 of the battery management system BMS; the energy control system EMS1 communicates with the external DC charging pile to determine charging, and obtains the status and charging parameters of each battery cluster through the column management unit BAU4.

[0090] S1-3: The energy control system EMS1 sends a closing signal to the relay KMd16 and simultaneously adjusts the four bidirectional DC-DC converters. The energy control system EMS1 adjusts the bidirectional DC-DCa19, bidirectional DC-DCb20, bidirectional DC-DCc21 and bidirectional DC-DCd22 according to the charging parameters of each battery cluster provided by the column management unit BAU4 to meet the charging requirements of each battery cluster.

[0091] S1-4: The column management unit BAU4 sends a charging signal to the PDU execution unit connected to each battery cluster; the PDU execution unit can provide safe and stable power distribution to the four battery clusters.

[0092] S1-5: Open the charging circuit to perform DC fast charging; the energy on the DC bus 18 is distributed to each battery cluster according to the status of the four bidirectional DC-DC converters.

[0093] S2-1: The DC voltage on the four battery clusters is adjusted to the same voltage platform through their respective bidirectional DC-DC converters, and the energy is concentrated on the DC bus 18.

[0094] S2-2: The DC power on DC bus 18 is converted into three-phase AC power after passing through the bidirectional PCS15 DC terminal;

[0095] S2-3: When relay KMc13 is closed, the three-phase AC power enters one end of ACCDC14 after passing through relay KMc13. The three-phase AC power is converted into the required DC power inside ACCDC14.

[0096] S2-4: The required DC power reaches the DC output main line 10 through the other end of ACDC14; the required DC output interface is connected to the DC output main line 10.

[0097] S2-5: DC power is output to an external DC load through the DC output interface for DC discharge.

[0098] The specific steps of AC charging and AC discharging are as follows:

[0099] S3-1: The AC charging dock 6 is connected to an external AC power plug;

[0100] S3-2: Energy control system EMS1 enters charging mode;

[0101] S3-3: Relay KMa7 automatically closes, and relays KMb8, KMc13 and KMd16 automatically open;

[0102] S3-4: After passing through relay KMa7, the AC power enters the bidirectional PCS15 AC terminal, where it is converted into DC power and enters the DC bus 18. After the AC power is converted into DC power and enters the DC bus 18, it immediately undergoes the same charging process as DC fast charging.

[0103] S3-5: The energy control system EMS1 communicates with the column management unit BAU4 of the battery management system BMS;

[0104] S3-6: The energy control system EMS1 sends a closing signal to the relay KMd16 and simultaneously adjusts the four bidirectional DC-DC converters;

[0105] S3-7: The column management unit BAU4 sends a charging signal to the PDU execution unit connected to each battery cluster;

[0106] S3-8: Open the charging circuit to begin AC charging;

[0107] S4-1: AC output interface 9 is connected to the AC load;

[0108] S4-2: Relays KMa7 and KMd16 are open, and relays KMb8 and KMc13 are closed;

[0109] S4-3: The DC power on DC bus 18 enters the DC terminal of bidirectional PCS15 and is converted into three-phase AC power;

[0110] S4-4: Three-phase AC power reaches AC output interface 9 after passing through relay KMb8;

[0111] S4-5: Three-phase AC power output to external AC loads for AC discharge.

[0112] In the aforementioned DC fast charging, DC discharging, AC charging, and AC discharging processes, the use of a battery pack composed of lithium iron phosphate and lithium titanate batteries enables the system to achieve fast charging at room temperature and direct start-up and operation at rated power in ultra-low temperature environments. During charging, the system can automatically determine the state parameters of each battery cluster and allocate different voltages and currents accordingly, allowing each cluster to charge simultaneously according to its appropriate charging parameters. When a faulty battery cluster occurs, the system can automatically activate control strategies to ensure normal operation, thereby improving system reliability. When the system is in a low-temperature or ultra-low-temperature operating environment, the thermal management system can automatically activate to intelligently heat the lithium iron phosphate battery clusters, restoring them to normal operating conditions and reducing system operating costs.

[0113] Of course, the above description is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the embodiments of the present invention. The present invention is also not limited to the above examples, and all equivalent changes and improvements made by those skilled in the art within the scope of the present invention should fall within the patent coverage of the present invention.

Claims

1. A mobile modular power station, characterized in that: It includes a housing, battery pack, electrical system, energy control system (EMS) (1), battery management system (BMS) and thermal management system; the battery pack includes lithium titanate battery cluster a (44), lithium iron phosphate battery cluster a (47), lithium titanate battery cluster b (50) and lithium iron phosphate battery cluster b (52); the independent circuits formed by the lithium titanate battery cluster a (44), lithium iron phosphate battery cluster a (47), lithium titanate battery cluster b (50) and lithium iron phosphate battery cluster b (52) are respectively connected in parallel to the DC bus (18) of the electrical system; The electrical system is equipped with a PDU execution unit PDUa (28), and a fuse a (35) is connected in series between the PDUa (28) and the positive electrode of the lithium titanate battery cluster a (44). The other three battery clusters are connected to their respective PDU execution units and fuses in the same way. The electrical system is equipped with a bidirectional DC-DCa (19), and a manual maintenance switch b (23) is connected in series between the bidirectional DC-DCa (19) and PDUa (28). The other three PDU execution units are connected to their respective bidirectional DC-DC and manual maintenance switches in the same way. The electrical system is equipped with two DC charging sockets: DC charging socket a (11) and DC charging socket b (12). The DC bus (18) of the electrical system is connected to the bidirectional PCS (15) via a manual maintenance switch a (17) and then divided into three branches; The electrical system is equipped with relays KMa (7) and KMb (8), which are high-voltage interlocked. The electrical system is equipped with a PCS monitoring unit (3), and the control power supply used by the PCS monitoring unit (3) and the battery management system (BMS) is a dual-power redundant configuration. The mobile modular power station can realize DC fast charging, DC discharging, AC charging, and AC discharging. The steps of DC fast charging, DC discharging, AC charging, and AC discharging are related as follows: S1: Connect to an external DC charging station to enable DC fast charging; S2: DC fast charging is off; when connected to an external DC load, DC discharge is on. S3: DC discharge off; connect an external AC power plug to start AC charging. S4: AC charging is off; when an external AC load is connected, AC discharging is on. The specific steps of the DC fast charging and DC discharging process are as follows: S1-1: DC charging dock a (11) and DC charging dock b (12) are respectively connected to an external DC charging pile; S1-2: The Energy Control System (EMS) (1) communicates with the column management unit (BAU) (4) of the external DC charging pile and the Battery Management System (BMS); S1-3: The energy control system EMS (1) sends a closing signal to the relay KMd (16) and simultaneously adjusts the four bidirectional DC-DC converters; S1-4: The column management unit BAU (4) sends a charging signal to the PDU execution unit connected to each battery cluster; S1-5: Open the charging circuit to perform DC fast charging; S2-1: The DC voltage on the four battery clusters is adjusted to the same voltage platform through their respective bidirectional DC-DC converters, and the energy is concentrated on the DC bus (18); S2-2: The DC power on the DC bus (18) is converted into three-phase AC power after passing through the DC terminal of the bidirectional PCS (15); S2-3: When relay KMc (13) is closed, the three-phase AC power enters one end of ACDC (14) after passing through relay KMc (13). The three-phase AC power is converted into the required DC power inside ACDC (14). S2-4: The required DC power reaches the DC output main line (10) through the other end of ACDC (14). S2-5: DC power is output to an external DC load through the DC output interface for DC discharge; The specific steps of AC charging and AC discharging are as follows: S3-1: The AC charging dock (6) is connected to an external AC power plug; S3-2: Energy Control System (EMS) (1) enters charging mode; S3-3: Relay KMa (7) closes automatically, and relays KMb (8), KMc (13) and KMd (16) open automatically; S3-4: After passing through relay KMa (7), the AC power enters the bidirectional PCS (15) AC terminal, and the AC power is converted into DC power and enters the DC bus (18). S3-5: The Energy Control System (EMS) (1) and the Column Management Unit (BAU) (4) of the Battery Management System (BMS) communicate with each other. S3-6: The energy control system EMS (1) sends a closing signal to the relay KMd (16) and simultaneously adjusts the four bidirectional DC-DC converters; S3-7: The column management unit BAU (4) sends a charging signal to the PDU execution unit connected to each battery cluster; S3-8: Open the charging circuit to begin AC charging; S4-1: AC output interface (9) is connected to the external AC load; S4-2: Relays KMa (7) and KMd (16) are open, and relays KMb (8) and KMc (13) are closed; S4-3: The DC power on the DC bus (18) enters the DC terminal of the bidirectional PCS (15), and the DC power is converted into three-phase AC power; S4-4: Three-phase AC power reaches the AC output interface (9) after passing through relay KMb (8). S4-5: Three-phase AC power output to external AC loads for AC discharge.

2. The mobile modular power station according to claim 1, characterized in that: The interior of the enclosure is divided into two independent battery compartments and an electrical compartment, with a firewall between them. The electrical compartment is connected to an external DC charging station and an AC power plug.

3. The mobile modular power station according to claim 1, characterized in that: The energy control system (EMS) (1) communicates with the electrical system, battery management system (BMS), external DC charging pile, and AC power plug.

4. A mobile modular power station according to claim 1, characterized in that: The lithium iron phosphate battery cluster a (47) is equipped with PTC heating a (48), and the lithium iron phosphate battery cluster b (52) is equipped with PTC heating b (53).

5. A mobile modular power station according to claim 1, characterized in that: The battery management system (BMS) has a three-level architecture, including an antenna (2), a human-machine interface (HMI) (5), a first-level column management unit (BAU) (4), a second-level battery cluster management unit (BPU), and a third-level battery module management unit (BMU).

6. A mobile modular power station according to claim 1, characterized in that: The electrical system includes a DC fast charging branch, a DC discharge branch, an AC charging branch, and an AC discharge branch. The DC fast charging branch includes: a DC bus (18) connected to DC charging socket a (11) and DC charging socket b (12) after passing through relay KMd (16); The DC discharge branch includes: a bidirectional PCS (15) connected to an ACDC (14) via a relay KMc (13), the other end of the ACDC (14) connected to a DC output main line (10), and the required DC output interface connected to the DC output main line (10); The AC charging branch includes: a bidirectional PCS (15) connected to an AC charging socket (6) via a relay KMa (7); The AC discharge branch includes: a bidirectional PCS (15) connected to the AC output interface (9) via a relay KMb (8).

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