Power battery ground charging control method, circuit, power supply system and rail vehicle

Abstract

The application provides a power battery ground charging control method, a circuit, a power supply system and a rail vehicle, and is applied to a power battery ground charging circuit of a rail vehicle, comprising a main ground charging device and a battery pack to be charged; the battery pack to be charged comprises at least two power battery packs; the method comprises the following steps: acquiring current voltage values of the power battery packs; in the case that there is a voltage difference between the power battery packs, a first charging path is controlled to be turned on, and the main ground charging device is used to charge a first power battery pack; in the case that the current voltage value of the first power battery pack is equal to the current voltage value of a second power battery pack, a second charging path is controlled to be turned on, and the main ground charging device is used to charge the first power battery pack and the second power battery pack simultaneously. The application can guarantee the emergency charging demand of the battery pack to be charged, has a fast charging speed and low cost.

Description

Technical Field

[0001] This invention relates to the field of rail transit technology, and provides a ground charging control method, circuit, power supply system, and rail vehicle for power batteries. Background Technology

[0002] With the limitations of existing overhead contact lines and the increasing demand for grid-free operation, many projects are exploring solutions powered by battery packs to adapt to the operational needs of grid-free areas. Typically, battery packs are charged via the overhead contact line or fuel cells. However, under certain operating conditions, charging requires dedicated ground-based charging equipment. For this purpose, charging interfaces are installed on the battery pack housings to allow for one-to-one charging via ground-based charging devices. However, when a train is equipped with multiple battery packs, some limitations arise. If only one ground-based charging device is configured, charging of the next battery cannot begin until one is fully charged, resulting in extended charging cycles. Summary of the Invention

[0003] This invention provides a method, circuit, power supply system, and rail vehicle for controlling ground charging of power batteries, addressing the shortcomings of existing ground charging devices that can only charge power batteries one-to-one and have long charging cycles. This invention can guarantee the emergency charging needs of battery packs, offering fast charging speeds and low costs.

[0004] This invention provides a ground charging control method for power batteries, applied to a ground charging circuit for power batteries in rail vehicles. The ground charging circuit includes a main ground charging device and a battery pack to be charged; the battery pack to be charged includes at least two power battery packs; the method includes: acquiring the current voltage value of each power battery pack; when there is a voltage difference between the power battery packs, controlling a first charging path to be activated, charging the first power battery pack through the main ground charging device; the first charging path is the charging path between the main ground charging device and the first power battery pack; when the current voltage value of the first power battery pack is equal to the current voltage value of the second power battery pack, controlling a second charging path to be activated, charging both the first power battery pack and the second power battery pack simultaneously through the main ground charging device; the second charging path is the charging path between the main ground charging device and the second power battery pack; the first power battery pack has a lower current voltage value, and the second power battery pack has a higher current voltage value; the first charging path and the second charging path are connected in parallel.

[0005] According to a ground charging control method for power batteries provided by the present invention, before obtaining the current voltage value of each power battery pack, the method further includes: controlling the power supply path of the battery control unit of each power battery pack to be turned on, and supplying power to the battery control unit through the main ground charging device; the power supply path is the path between the main ground charging device and the battery control unit.

[0006] The ground charging control method for power batteries provided by the present invention further includes: monitoring the status of the main ground charging device and the battery pack to be charged, and determining a charging control strategy according to the fault type in the event of a fault.

[0007] According to a ground charging control method for power batteries provided by the present invention, in the event of a fault, determining a charging control strategy based on the fault type includes: if a first-level fault occurs in the battery pack to be charged, the charging control strategy is to issue a first-level fault alarm and control the charging voltage and current reduction; if a second-level fault occurs in the battery pack to be charged, the charging control strategy is to issue a second-level fault alarm and control the charging voltage and current reduction; if a third-level fault occurs in the battery pack to be charged, the charging control strategy is to issue a third-level fault alarm and disconnect charging of the battery pack to be charged; if a fault occurs in the main ground charging device, the charging control strategy is to issue a device fault alarm and disconnect charging of the battery pack to be charged.

[0008] According to the present invention, a ground charging control method for a power battery includes a coil of a first normally open relay in the first power supply path. When the coil of the first normally open relay is energized, the first power supply path and the second power supply path are connected. The first power supply path is the power supply path of a first battery control unit, and the second power supply path is the power supply path of a second battery control unit. The first battery control unit is the battery control unit of the first power battery pack, and the second battery control unit is the battery control unit of the second power battery pack.

[0009] According to a ground charging control method for a power battery provided by the present invention, the first charging path includes the contact of a first normally open relay; when the coil of the first normally open relay is energized, the contact of the first normally open relay closes, the contactor of the first battery control unit closes, the contactor of the control unit of the main ground charging device closes, and the first charging path is connected; when the contact of the first normally open relay is closed, the contactor of the second battery control unit closes, and the second charging path is connected.

[0010] According to a power battery ground charging control method provided by the present invention, the first power supply path further includes a first isolation element; the power battery ground charging circuit further includes a backup ground charging device; the backup power supply path of the backup ground charging device includes a second isolation element and a coil of a second normally open relay; the backup power supply path is a backup power supply path for the first battery control unit and the second battery control unit; the charging output terminal of the backup ground charging device is connected to one end of the contact of the second normally open relay, and the other end of the contact of the second normally open relay is connected to the second charging path; the first isolation element is connected to the second isolation element, and the coil of the first normally open relay is connected to the coil of the second normally open relay; when the first isolation element is energized, the second isolation element and the coil of the second normally open relay are not energized, and the contact of the second normally open relay is open.

[0011] According to a ground charging control method for a power battery provided by the present invention, the first isolation element is a first diode, and the second isolation element is a second diode; the anode of the first diode is connected to the positive terminal of the coil of the first normally open relay, the cathode of the first diode is connected to the cathode of the second diode, and the anode of the second diode is connected to the positive terminal of the coil of the second normally open relay.

[0012] According to a ground charging control method for a power battery provided by the present invention, the first isolation element includes a coil of a first normally closed relay and a contact of a second normally closed relay, and the second isolation element includes a contact of a first normally closed relay and a coil of a second normally closed relay; the positive terminal of the coil of the first normally open relay is connected to one end of the positive terminal of the coil of the first normally closed relay and one end of the contact of the second normally closed relay, respectively; the negative terminal of the coil of the first normally open relay is connected to the negative terminals of the coils of the first normally closed relay, the second normally open relay, and the second normally closed relay; the other end of the contact of the second normally closed relay is connected to one end of the contact of the first normally closed relay, and the other end of the contact of the first normally closed relay is connected to the positive terminals of the coils of the second normally open relay and the second normally closed relay.

[0013] According to a ground charging control method for a power battery provided by the present invention, the emergency charging socket of the rail vehicle is located at a preset position under the body of the rail vehicle; the main ground charging device performs emergency charging of the battery pack to be charged through the emergency charging socket.

[0014] According to a ground charging control method for a power battery provided by the present invention, the emergency charging socket includes a charging position, a power supply position, and a communication position; the charging position is the position for connecting the positive and negative terminals of the battery pack to be charged, the power supply position is the position for connecting the positive and negative terminals of the battery control unit of the battery pack to be charged, and the communication position is the position for the battery control unit of the battery pack to be charged to communicate with the main ground charging device.

[0015] The present invention also provides a ground charging circuit for a power battery, including a main ground charging device and a battery pack to be charged; the battery pack to be charged includes at least two power battery packs; the ground charging circuit for the power battery uses the above-mentioned ground charging control method for the power battery for charging control.

[0016] The present invention also provides a vehicle power supply system, including the above-mentioned power battery ground charging circuit.

[0017] The present invention also provides a rail vehicle that uses the above-described vehicle power supply system for emergency charging.

[0018] This invention provides a ground charging control method, circuit, power supply system, and rail vehicle for power batteries. The ground charging circuit for power batteries in rail vehicles includes a main ground charging device and a battery pack to be charged. The battery pack to be charged includes at least two power battery packs. The method includes: acquiring the current voltage value of each power battery pack; when there is a voltage difference between the power battery packs, controlling the first charging path to conduct, charging the first power battery pack through the main ground charging device; when the current voltage value of the first power battery pack is equal to the current voltage value of the second power battery pack, controlling the second charging path to conduct, charging both the first and second power battery packs simultaneously through the main ground charging device. This invention can guarantee the emergency charging needs of the battery packs to be charged, with fast charging speed and low cost. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a flowchart illustrating the ground charging control method for power batteries provided by the present invention.

[0021] Figure 2 This is a schematic diagram of the specific process of the ground charging control method for power batteries provided by the present invention.

[0022] Figure 3This is a schematic diagram of the fault sub-process provided by the present invention.

[0023] Figure 4 This is a schematic diagram of the structure of the rail vehicle provided by the present invention.

[0024] Figure 5 This is one of the structural schematic diagrams of the power battery ground charging circuit provided by the present invention.

[0025] Figure 6 This is the second schematic diagram of the power battery ground charging circuit provided by the present invention.

[0026] Figure 7 This is a structural schematic diagram of the emergency charging socket provided by the present invention.

[0027] Figure 8 This is a schematic diagram of the power battery pack provided by the present invention.

[0028] Figure 9 This is a schematic diagram of the structure of the ground charging device provided by the present invention. Detailed Implementation

[0029] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0030] With the limitations of existing overhead contact lines and the future need for grid-free operation, an increasing number of projects are beginning to explore battery power to meet the requirements of grid-free areas. While batteries are typically charged via the overhead contact line or fuel cells, special operating conditions necessitate charging using dedicated ground-based charging devices. Charging sockets are installed on the battery packs, allowing for one-to-one charging via these devices. However, this presents limitations when a train carries multiple battery packs. If only one charging device is installed, one can only charge another after the previous one has been completed, resulting in long charging times.

[0031] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating the ground charging control method for power batteries provided by the present invention.

[0032] Please refer to Figure 2 , Figure 2 A schematic diagram illustrating the specific process of the power battery ground charging control method provided by the present invention.

[0033] This invention provides a ground charging control method for power batteries, applied to the ground charging circuit of power batteries in rail vehicles. The ground charging circuit includes a main ground charging device and a battery pack to be charged; the battery pack to be charged includes at least two power battery packs.

[0034] The method includes:

[0035] 101: Obtain the current voltage value of each power battery pack;

[0036] 102: When there is a voltage difference between the power battery packs, control the first charging path to be turned on, and charge the first power battery pack through the main ground charging device; the first charging path is the charging path between the main ground charging device and the first power battery pack.

[0037] 103: When the current voltage of the first power battery pack is equal to the current voltage of the second power battery pack, control the second charging path to be turned on, and charge the first power battery pack and the second power battery pack simultaneously through the main ground charging device; the second charging path is the charging path between the main ground charging device and the second power battery pack; the first power battery pack is the power battery pack with the lower current voltage value, and the second power battery pack is the power battery pack with the higher current voltage value; the first charging path and the second charging path are connected in parallel.

[0038] To address the technical problems existing in the prior art, this invention provides a ground charging control method for power batteries to ensure that the power battery packs of rail vehicles can be charged efficiently and safely. The ground charging circuit for the power batteries of the rail vehicle includes a main ground charging device and battery packs to be charged; each battery pack includes at least two power battery packs. Each power battery pack contains several power battery cells, which are connected in series or parallel to form the required voltage and capacity. The method of this invention first obtains the current voltage value of each power battery pack. This can be achieved by a voltage sensor connected to each battery pack, which transmits the voltage value to the battery control unit of the power battery pack in real time. The battery control unit sends the received voltage value to the control unit of the ground charging device in the form of a message (which may also include a request for charging current value). The control unit of the ground charging device determines the voltage difference between the battery packs.

[0039] When a voltage difference is detected between different power battery packs, the first charging path is activated. This path connects the main ground charging device to the first power battery pack with the lower voltage. At this time, the main ground charging device delivers electrical energy to the first power battery pack until its voltage reaches the preset charging cutoff voltage.

[0040] When the voltage of the first power battery pack (Power Battery 1) equals that of the second power battery pack (Power Battery 2), which has a higher voltage, the second charging path is activated. This allows the main ground charging device to charge both the first and second power battery packs simultaneously. Charging can be interrupted at any time to ensure that the voltage and SOC of each battery pack remain consistent. At this time, the first and second charging paths are connected in parallel, allowing current to be distributed between the two battery packs to balance their voltages.

[0041] This control method automatically identifies the charging sequence when the initial voltages of the power batteries in different compartments are inconsistent. This more intelligent approach ensures voltage balance in the power battery packs of rail vehicles during charging, preventing overcharging or undercharging, thereby extending battery life and improving charging efficiency. Furthermore, this method is flexible, adaptable to different power battery pack configurations, and meets the charging needs of various rail vehicles.

[0042] As a preferred embodiment, before obtaining the current voltage value of each power battery pack, the method further includes: controlling the power supply path of the battery control unit of each power battery pack to be turned on, and supplying power to the battery control unit through the main ground charging device; the power supply path is the path between the main ground charging device and the battery control unit.

[0043] In this embodiment, each battery pack is equipped with a Battery Management System (BMS), which is responsible for monitoring and managing the status of the battery pack, including key parameters such as voltage, current, and temperature. The BMS is crucial for ensuring battery safety, extending battery life, and optimizing the charging process. Before acquiring the voltage values ​​of each battery pack, the power supply path to the BMS of each battery pack is controlled to ensure that the BMS has sufficient power before voltage monitoring, thereby enabling it to accurately perform its monitoring and control functions.

[0044] Specifically, the main ground-based charging unit supplies power to the BMS of each battery pack via a power supply path. This power supply path is a direct connection between the main ground-based charging unit and the battery control unit. The activation of the power supply path can be achieved via a control switch or circuit controlled by the central control unit. Once the power supply path is activated, the main ground-based charging unit provides a stable power supply to the BMS, enabling it to begin operation.

[0045] The ground charging control method for power batteries of this invention not only ensures that the power battery pack is effectively monitored by the BMS before charging, but also improves the safety and reliability of the entire charging process. This pre-power supply mechanism provides a solid foundation for subsequent voltage monitoring and charging control, making the charging process more precise and efficient. Furthermore, it also helps to promptly detect and address any potential battery problems, thereby protecting the battery from damage and ensuring the safe operation of the rail vehicle.

[0046] As a preferred embodiment, it further includes: monitoring the status of the main ground charging device and the battery pack to be charged, and determining a charging control strategy based on the fault type in the event of a fault.

[0047] In this embodiment, the control unit of the main ground charging device monitors the status of the main ground charging device, and the battery control unit of the battery pack to be charged monitors the status of the battery pack to be charged. For example, it can collect key parameters such as voltage, current, temperature, and charging status, and then determine the fault type according to preset thresholds and logic.

[0048] When an abnormal situation is detected, such as voltage exceeding the safe range, abnormal current, excessive temperature, or battery pack charging status not meeting expectations, a fault diagnosis procedure will be triggered. The fault diagnosis procedure will determine the specific fault type based on the collected data and a pre-defined fault code library.

[0049] Once the fault type is determined, the corresponding charging control strategy will be executed. For example, if an overheating fault is detected, the control strategy may include reducing the charging current, suspending charging, or activating the cooling system. If a voltage anomaly is detected, the control strategy may include adjusting the charging voltage or switching to a backup charging path.

[0050] This embodiment increases the flexibility and intelligence of the charging circuit. In the event of a fault, it can automatically adjust the charging strategy to protect the battery pack and charging device, reducing the impact of the fault.

[0051] In a preferred embodiment, in the event of a fault, a charging control strategy is determined based on the fault type, including: in the case of a Level 1 fault in the battery pack to be charged, the charging control strategy is to issue a Level 1 fault alarm and control the charging voltage and current reduction; in the case of a Level 2 fault in the battery pack to be charged, the charging control strategy is to issue a Level 2 fault alarm and control the charging voltage and current reduction; in the case of a Level 3 fault in the battery pack to be charged, the charging control strategy is to issue a Level 3 fault alarm and disconnect the charging of the battery pack to be charged; and in the case of a fault in the main ground charging device, the charging control strategy is to issue a device fault alarm and disconnect the charging of the battery pack to be charged.

[0052] Please refer to Figure 3 , Figure 3 This is a schematic diagram of the fault sub-process provided by the present invention.

[0053] In this embodiment, a graded fault response mechanism is established, which can execute different control strategies according to the severity of the fault. Faults are classified into Level 1 faults, Level 2 faults, Level 3 faults, and main ground charging device faults. Each level of fault corresponds to different alarm prompts and charging control measures.

[0054] When a primary fault occurs in the battery pack to be charged, the charging control strategy implemented includes a primary fault alarm flag and control of charging voltage and current reduction. Voltage reduction means lowering the charging voltage, while current reduction means reducing the charging current. This strategy aims to minimize further damage to the battery pack from the fault while attempting to maintain the battery's basic charging needs.

[0055] When a secondary fault occurs in the battery pack to be charged, the charging control strategy implemented includes a primary fault alarm flag, and controls the charging voltage and current reduction, and the alarm is uploaded to the HMI.

[0056] When a Level 3 fault occurs in the battery pack to be charged, a more stringent control strategy will be implemented. This includes displaying a Level 3 fault alarm, completely disconnecting charging of the battery pack, and uploading the alarm to the HMI. Level 3 faults typically refer to situations that may cause serious damage to the battery pack or pose a safety hazard, thus requiring immediate cessation of charging to prevent further damage.

[0057] When the main ground charging unit malfunctions, an alarm will be sent to the HMI, and charging of the battery pack to be charged will be disconnected. This is because a malfunction of the main ground charging unit may affect the safety and effectiveness of the entire charging process, thus requiring immediate cessation of charging to protect the battery pack.

[0058] The system will then determine whether the contactors of the battery control unit of the battery pack to be charged and the control unit of the main ground charging device are disconnected. If the contactors are not disconnected, a shutdown command for the main ground charging device will be sent to force a power outage.

[0059] Please refer to Figure 4 , Figure 4 This is a schematic diagram of the structure of the rail vehicle provided by the present invention.

[0060] In a preferred embodiment, the first power supply path includes the coil of a first normally open relay. When the coil of the first normally open relay is energized, the first power supply path and the second power supply path are connected. The first power supply path is the power supply path of the first battery control unit, and the second power supply path is the power supply path of the second battery control unit. The first battery control unit is the battery control unit of the first power battery pack, and the second battery control unit is the battery control unit of the second power battery pack.

[0061] In this embodiment, the conduction status of the first power supply path and the second power supply path is controlled by using a first normally open relay to realize the power supply to the battery control unit (BMS) of the first power battery pack and the second power battery pack.

[0062] The main ground charging unit supplies power to the first battery control unit and the second battery control unit via two independent power supply paths. These two power supply paths are the first power supply path and the second power supply path, respectively, and they are connected to the BMS of the first power battery pack and the second power battery pack.

[0063] A coil of a first normally open relay is installed on the first power supply path. When the coil of the first normally open relay is energized, the first and second power supply paths are connected, ensuring that both BMSs receive power simultaneously. This allows for simultaneous monitoring and management of the status of both battery packs. This embodiment improves the safety and reliability of the charging process, while also increasing charging efficiency because it allows both BMSs to operate simultaneously, reducing charging preparation time. Furthermore, this design helps achieve more accurate battery pack voltage balance during charging, thereby extending battery life and improving the overall efficiency of the charging system.

[0064] In a preferred embodiment, the first charging path includes the contacts of a first normally open relay; when the coil of the first normally open relay is energized, the contacts of the first normally open relay close, the contactor of the first battery control unit closes, the contactor of the control unit of the main ground charging device closes, and the first charging path is activated; when the contacts of the first normally open relay are closed, the contactor of the second battery control unit closes, and the second charging path is activated.

[0065] In this embodiment, the normally open relay is an electronic switch that is open when not energized. When the coil is energized, the relay contacts close, thereby completing the circuit. When the main ground charging device supplies power to the coil of the first normally open relay, the coil generates a magnetic field, causing the contacts of the first normally open relay to close. The closing of the contacts of the first normally open relay triggers the contactor of the first battery control unit to close, which in turn triggers the contactor of the control unit of the main ground charging device to close, thus establishing the first charging path between the first power battery pack and the main ground charging device, ensuring that electrical energy from the main ground charging device can flow to the first power battery pack.

[0066] When the current voltage of the first power battery pack is equal to that of the second power battery pack, both power battery packs need to be charged simultaneously. When the contacts of the first normally open relay remain closed, the contactor of the second battery control unit will also close. Since the contactor of the main ground charging unit's control unit is already closed, this opens the second charging path, allowing the main ground charging unit to charge both the first and second power battery packs simultaneously.

[0067] In a preferred embodiment, the first power supply path further includes a first isolation element; the power battery ground charging circuit further includes a backup ground charging device; the backup power supply path of the backup ground charging device includes a second isolation element and a coil of a second normally open relay; the backup power supply path is a backup power supply path for the first battery control unit and the second battery control unit; the charging output terminal of the backup ground charging device is connected to one end of the contact of the second normally open relay, and the other end of the contact of the second normally open relay is connected to the second charging path; the first isolation element is connected to the second isolation element, and the coil of the first normally open relay is connected to the coil of the second normally open relay; when the first isolation element is energized, the second isolation element and the coil of the second normally open relay are not energized, and the contact of the second normally open relay is open.

[0068] To ensure the battery pack continues to receive necessary charging in the event of a failure in the main ground charging unit, this embodiment firstly adds a first isolation element to the first power supply path. This element ensures a stable power supply to the first battery control unit when the main ground charging unit is operating normally. Simultaneously, a backup ground charging unit is introduced, providing backup power to both the first and second battery control units via a backup power supply path. This backup power supply path includes a second isolation element and the coil of a second normally open relay.

[0069] The backup ground charging device's charging output terminal is connected to one end of the contact of the second normally open relay, and the other end of the contact of the second normally open relay is connected to the second charging path. In this way, when the main ground charging device fails, the backup ground charging device can supply power to the second charging path through the contact of the second normally open relay, ensuring that the second power battery pack can continue to charge.

[0070] The first isolation element is connected to the second isolation element, meaning that when the first isolation element is energized, the second isolation element will not be energized, thus ensuring that the coil of the second normally open relay is also de-energized, causing the contacts of the second normally open relay to remain open. This design ensures that the backup ground charging unit will not intervene when the primary ground charging unit is working normally; the backup ground charging unit will only be activated when the primary ground charging unit fails.

[0071] This embodiment not only improves the safety and reliability of the charging process but also increases redundancy, ensuring that the power battery pack can still receive necessary charging in the event of a failure in the main ground charging unit, thereby guaranteeing the continuous operation of the rail vehicles. This redundancy design is crucial for improving the stability and reliability of the entire charging system, especially in critical transportation systems, ensuring the continuity and reliability of service.

[0072] In a preferred embodiment, the first isolation element is a first diode, and the second isolation element is a second diode; the anode of the first diode is connected to the positive terminal of the coil of the first normally open relay, the cathode of the first diode is connected to the cathode of the second diode, and the anode of the second diode is connected to the positive terminal of the coil of the second normally open relay.

[0073] Please refer to Figure 5 , Figure 5 This is one of the structural schematic diagrams of the power battery ground charging circuit provided by the present invention.

[0074] In this embodiment, the control of the main ground charging device and the backup ground charging device is achieved by using a first diode and a second diode as isolation elements. The first isolation element is the first diode, and the second isolation element is the second diode. A diode is an electronic component that allows current to flow in only one direction, and it has an anode and a cathode. In this embodiment, the anode of the first diode is connected to the positive terminal of the coil of the first normally open relay, while the cathode of the first diode is connected to the cathode of the second diode. Similarly, the anode of the second diode is connected to the positive terminal of the coil of the second normally open relay. This connection method ensures that when the first diode is conducting, the current can only flow from the first normally open relay to the second diode, and cannot flow in the reverse direction. This means that when the main ground charging device is working normally, the first diode conducts, energizing the coil of the first normally open relay, thereby controlling the first power supply path and the first charging path. At this time, the second diode, due to reverse bias, prevents current from flowing to the coil of the second normally open relay, ensuring that the contacts of the second normally open relay remain open, thereby preventing the intervention of the backup ground charging device.

[0075] In this embodiment, when the primary ground charging device fails, the first diode will turn off, allowing current to flow to the coils of the second diode and the second normally open relay, thereby activating the backup ground charging device. This automatic switching mechanism ensures that the power battery pack can be stably charged under any circumstances, improving the stability and reliability of the entire charging system.

[0076] In a preferred embodiment, the first isolation element includes the coil of a first normally closed relay and the contact of a second normally closed relay, and the second isolation element includes the contact of the first normally closed relay and the coil of the second normally closed relay; the positive terminal of the coil of the first normally open relay is connected to one end of the positive terminal of the coil of the first normally closed relay and one end of the contact of the second normally closed relay, respectively; the negative terminal of the coil of the first normally open relay is connected to the negative terminals of the coils of the first normally closed relay, the second normally open relay, and the second normally closed relay; the other end of the contact of the second normally closed relay is connected to one end of the contact of the first normally closed relay, and the other end of the contact of the first normally closed relay is connected to the positive terminal of the coil of the second normally open relay and the second normally closed relay.

[0077] Please refer to Figure 6 , Figure 6 The second schematic diagram of the power battery ground charging circuit provided by the present invention.

[0078] In this embodiment, the first isolation element includes the coil of a first normally closed relay and the contacts of a second normally closed relay, and the second isolation element includes the contacts of the first normally closed relay and the coil of a second normally closed relay. This design utilizes the characteristics of relays, where the contacts of a normally closed relay are closed when not energized, and the contacts of a normally open relay are open when not energized. In this configuration, the positive terminal of the coil of the first normally open relay is connected to the positive terminal of the coil of the first normally closed relay and one end of the contact of the second normally closed relay, and the negative terminal of the coil of the first normally open relay is connected to the negative terminals of the coils of the first normally closed relay, the second normally open relay, and the second normally closed relay. This connection ensures that when the ground charging device is in operation, the coil of the first normally closed relay between A3+ and A3- is energized, the coil of the first normally open relay between A1+ and A1- is energized, the coil of the second normally closed relay between A4+ and A4- is not energized, the contact KM4 of the second normally closed relay is closed, the contact KM1 of the first normally open relay is closed, and the first charging path and the second charging path are connected.

[0079] The other end of the contact of the second normally closed relay is connected to one end of the contact of the first normally closed relay, while the other end of the contact of the first normally closed relay is connected to the positive terminals of the coils of the second normally open relay and the second normally closed relay, respectively. This design ensures that when the main ground charging device is operating, the contact KM3 of the first normally closed relay is open, the coil of the second normally open relay between A2+ and A2- is not energized, and the contact KM2 of the second normally open relay remains open, thereby blocking the power supply path of the backup ground charging device.

[0080] In a preferred embodiment, the emergency charging socket of the rail vehicle is located at a preset position under the body of the rail vehicle; the main ground charging device uses the emergency charging socket to charge the battery pack to be charged.

[0081] In this embodiment, the emergency charging socket of the rail vehicle is installed at a predetermined location under the vehicle body, so that it is not necessary to climb to the top for emergency charging. The selection of this predetermined location takes into account the vehicle's dynamic characteristics, safety, and ease of charging operation. The emergency charging socket is designed to be quickly connected and disconnected so as to quickly provide power to the rail vehicle's battery pack in emergency situations.

[0082] Emergency charging sockets include necessary electrical connection terminals and sealing mechanisms to ensure they are not affected by environmental factors such as dust and moisture while the vehicle is in operation, and to safely transfer electrical energy during charging. The socket design also takes into account mechanical strength and durability to withstand wear and pressure during daily operation.

[0083] In case of emergency charging, the main ground charging unit connects to the emergency charging socket via a specially designed charging cable. This charging cable is designed to withstand high current and voltage while being flexible enough to adapt to different charging locations and angles.

[0084] The number of emergency charging sockets can be flexibly set according to the train model, for example, one on each side of the train. This invention does not impose any special limitation on this.

[0085] This embodiment improves the emergency response capability of the charging circuit. In emergency situations, the rail vehicle can quickly obtain power through the emergency charging socket, ensuring continuous vehicle operation and uninterrupted service.

[0086] In a preferred embodiment, the emergency charging socket includes a charging position, a power supply position, and a communication position; the charging position is the location for connecting the positive and negative terminals of the battery pack to be charged, the power supply position is the location for connecting the positive and negative terminals of the battery control unit of the battery pack to be charged, and the communication position is the location for the battery control unit of the battery pack to be charged to communicate with the main ground charging device.

[0087] Please refer to Figure 7 , Figure 7 This is a schematic diagram of the structure of the emergency charging socket provided by the present invention.

[0088] In this embodiment, the emergency charging socket is a multi-functional interface comprising three main positions: a charging position, a power supply position, and a communication position. These positions are designed to enable efficient, safe, and intelligent charging of the rail vehicle's battery packs.

[0089] The charging position is the location in the emergency charging socket used to connect the positive and negative terminals of the battery pack to be charged. It includes two terminals, corresponding to the positive (B) and negative (G) terminals of the battery, respectively. During emergency charging, the main ground charging unit provides power to the battery pack through the charging position for rapid charging. The design of the charging position ensures efficient power transmission while avoiding the risks of short circuits or overloads.

[0090] The power supply position is the location in the emergency charging socket where the positive and negative power supply terminals (D-1, D-2) of the battery control system (BMS) of the battery pack being charged are connected. The BMS is a critical component for monitoring and managing battery status, and it requires a stable power supply to perform its functions. The power supply position provides the necessary power connection for the BMS, ensuring its continuous operation during charging.

[0091] The communication bits (D-3, D-4) are located in the emergency charging socket to enable communication between the battery control unit of the battery pack to be charged and the main ground charging device. These communication bits include the necessary interfaces and protocols to achieve bidirectional data transmission. Through these communication bits, the BMS can send battery status information, such as voltage, current, and temperature, to the main ground charging device, which can then adjust its charging strategy based on this information.

[0092] For example, the entire train is equipped with two power battery packs (the first power battery pack and the second power battery pack), and two emergency charging sockets (X1 and X2), located on both sides of the train.

[0093] When the power battery is depleted, it can be charged by the ground charging device through the emergency charging socket, allowing parallel charging of two power battery boxes. A+ and A- are the positive and negative DC 24V respectively, and a relay coil is located between A+ and A-, driving the corresponding contacts through the relay. S+ and S- are communication lines, and D1 and D2 are diodes. When charging through X1, the ground charging device outputs 24V to the power battery control unit (BMS). The power battery control unit (BMS) communicates with the ground charging device, energizing the coil of the first normally open relay between A1+ and A1- on this side, and closing the contact KM1 of the first normally open relay. After status confirmation, each power battery BMS controls its own high-voltage contactor to close, and then the ground charging device control unit controls its own contactor to close, applying high voltage to charge the power battery. On the other side, because diode D2 is cut off, the coil of the second normally open relay between A2+ and A2- cannot be energized, and the contact KM2 of the second normally open relay remains open, meaning X2 is not energized, preventing personnel from being shocked by accidental contact with X2 and protecting personal safety.

[0094] Please refer to Figure 8 , Figure 8 This is a schematic diagram of the power battery pack provided by the present invention.

[0095] Furthermore, the structure of the power battery pack may include battery modules, fuses (FU1, FU2), main contactors (K1, K2), pre-charge contactor (K3), emergency charging contactor (K4), voltage sensor, current sensor, maintenance switch (MSD), etc. The power battery is equipped with an emergency charging interface (positive and negative for battery charging), which can be charged through a ground charging device. This invention does not impose any particular limitations on this.

[0096] Please refer to Figure 9 , Figure 9 This is a schematic diagram of the structure of the ground charging device provided by the present invention.

[0097] The ground charging device may include an in-cabin power supply (380V), an AD / DC module, and a contactor, etc., and the present invention does not impose any particular limitation.

[0098] The power battery ground charging circuit provided by the present invention is described below. The power battery ground charging circuit described below and the power battery ground charging method described above can be referred to in correspondence.

[0099] The present invention also provides a ground charging circuit for a power battery, including a main ground charging device and a battery pack to be charged; the battery pack to be charged includes at least two power battery packs; the ground charging circuit for the power battery uses the above-mentioned ground charging control method for the power battery to control the charging.

[0100] The vehicle power supply system provided by the present invention is described below. The vehicle power supply system described below can be referred to in correspondence with the power battery ground charging method described above.

[0101] The present invention also provides a vehicle power supply system, including the above-mentioned power battery ground charging circuit.

[0102] The rail vehicle provided by the present invention is described below. The rail vehicle described below and the ground charging method for power batteries described above can be referred to in correspondence.

[0103] The present invention also provides a rail vehicle that uses the above-described vehicle power supply system for emergency charging.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling ground charging of a power battery, characterized in that, A ground charging circuit for power batteries used in rail vehicles, the power battery ground charging circuit includes a main ground charging device and a battery pack to be charged; The battery pack to be charged includes at least two power battery packs; the method includes: Obtain the current voltage value of each power battery pack; When there is a voltage difference between the power battery packs, the first charging path is controlled to be turned on, and the first power battery pack is charged through the main ground charging device; the first charging path is the charging path between the main ground charging device and the first power battery pack. When the current voltage of the first power battery pack is equal to the current voltage of the second power battery pack, the second charging path is activated, and the first power battery pack and the second power battery pack are charged simultaneously through the main ground charging device; the second charging path is the charging path between the main ground charging device and the second power battery pack; the first power battery pack is the power battery pack with the lower current voltage, and the second power battery pack is the power battery pack with the higher current voltage; the first charging path and the second charging path are connected in parallel; The first power supply path includes the coil of a first normally open relay. When the coil of the first normally open relay is energized, the first power supply path and the second power supply path are connected. The first power supply path is the power supply path of the first battery control unit, and the second power supply path is the power supply path of the second battery control unit. The first battery control unit is the battery control unit of the first power battery pack, and the second battery control unit is the battery control unit of the second power battery pack.

2. The power battery ground charging control method according to claim 1, characterized in that, Before obtaining the current voltage value of each power battery pack, the process also includes: The power supply path of the battery control unit of each power battery pack is turned on, and the main ground charging device supplies power to the battery control unit; the power supply path is the path between the main ground charging device and the battery control unit.

3. The power battery ground charging control method according to claim 1, characterized in that, Also includes: The status of the main ground charging device and the battery pack to be charged is monitored, and in the event of a fault, the charging control strategy is determined according to the fault type.

4. The power battery ground charging control method according to claim 3, characterized in that, In the event of a fault, determining the charging control strategy based on the fault type includes: In the event of a Level 1 fault in the battery pack to be charged, the charging control strategy is to issue a Level 1 fault alarm and control the charging voltage and current to be reduced. In the event of a secondary fault in the battery pack to be charged, the charging control strategy is to issue a secondary fault alarm and control the charging voltage and current reduction. In the event of a Level 3 fault in the battery pack to be charged, the charging control strategy is to issue a Level 3 fault alarm and disconnect the charging of the battery pack to be charged. In the event of a malfunction in the main ground charging device, the charging control strategy is to issue a device malfunction alarm and disconnect the charging of the battery pack to be charged.

5. The power battery ground charging control method according to claim 1, characterized in that, The first charging path includes the contacts of a first normally open relay; When the coil of the first normally open relay is energized, the contacts of the first normally open relay close, the contactor of the first battery control unit closes, the contactor of the control unit of the main ground charging device closes, and the first charging path is connected. When the contacts of the first normally open relay are closed, the contactor of the second battery control unit closes, and the second charging path is activated.

6. The power battery ground charging control method according to claim 5, characterized in that, The first power supply path also includes a first isolation element; the power battery ground charging circuit also includes a backup ground charging device; the backup power supply path of the backup ground charging device includes a second isolation element and a coil of a second normally open relay; the backup power supply path is the backup power supply path for the first battery control unit and the second battery control unit. The charging output terminal of the backup ground charging device is connected to one end of the contact of the second normally open relay, and the other end of the contact of the second normally open relay is connected to the second charging path; the first isolation element is connected to the second isolation element, and the coil of the first normally open relay is connected to the coil of the second normally open relay. When the first isolation element is energized, the coils of the second isolation element and the second normally open relay are not energized, and the contacts of the second normally open relay are open.

7. The power battery ground charging control method according to claim 6, characterized in that, The first isolation element is a first diode, and the second isolation element is a second diode; the anode of the first diode is connected to the positive terminal of the coil of the first normally open relay, the cathode of the first diode is connected to the cathode of the second diode, and the anode of the second diode is connected to the positive terminal of the coil of the second normally open relay.

8. The power battery ground charging control method according to claim 6, characterized in that, The first isolation element includes the coil of the first normally closed relay and the contact of the second normally closed relay, and the second isolation element includes the contact of the first normally closed relay and the coil of the second normally closed relay. The positive terminal of the coil of the first normally open relay is connected to the positive terminal of the coil of the first normally closed relay and one end of the contact of the second normally closed relay. The negative terminal of the coil of the first normally open relay is connected to the negative terminals of the coils of the first normally closed relay, the second normally open relay, and the second normally closed relay. The other end of the contact of the second normally closed relay is connected to one end of the contact of the first normally closed relay. The other end of the contact of the first normally closed relay is connected to the positive terminals of the coils of the second normally open relay and the second normally closed relay.

9. The power battery ground charging control method according to any one of claims 1 to 8, characterized in that, The emergency charging socket of the rail vehicle is located at a preset position under the body of the rail vehicle; the main ground charging device provides emergency charging for the battery pack to be charged through the emergency charging socket.

10. The power battery ground charging control method according to claim 9, characterized in that, The emergency charging socket includes a charging position, a power supply position, and a communication position; the charging position is the location for connecting the positive and negative terminals of the battery pack to be charged, the power supply position is the location for connecting the positive and negative terminals of the battery control unit of the battery pack to be charged, and the communication position is the location for the battery control unit of the battery pack to be charged to communicate with the main ground charging device.

11. A ground charging circuit for a power battery, characterized in that, It includes a main ground charging device and a battery pack to be charged; the battery pack to be charged includes at least two power battery packs; the power battery ground charging circuit uses the power battery ground charging control method according to any one of claims 1 to 10 for charging control.

12. A vehicle power supply system, characterized in that, Includes the power battery ground charging circuit as described in claim 11.

13. A rail vehicle, characterized in that, Emergency charging is performed using the vehicle power supply system described in claim 12.

Images