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

Abstract

The invention provides a power battery ground charging control method and circuit, a power supply system and a rail vehicle, and the power battery ground charging circuit applied to the rail vehicle comprises 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 a current voltage value of each power battery pack; under the condition that the voltage difference exists between the power battery packs, the first charging path is controlled to be conducted, and the first power battery pack is charged through the main ground charging device; under the condition that the current voltage value of the first power battery pack is equal to the current voltage value of the second power battery pack, the second charging path is controlled to be conducted, and the first power battery pack and the second power battery pack are charged at the same time through the main ground charging device. The emergency charging requirement of the to-be-charged battery pack can be ensured, the charging speed is high, and the cost is low.

Description

Technical Field

[0001] The present invention relates to the technical field of rail transit, and provides a power battery ground charging control method, a circuit, a power supply system and a rail vehicle. Background Art

[0002] With the limitations of existing overhead line capacity and the growing demand for off-grid operation, many projects have begun to explore solutions using power batteries to meet the operation needs of off-grid areas. Normally, power batteries are charged conventionally through overhead lines or fuel cells. However, under certain operating conditions, it is necessary to rely on dedicated ground charging devices for charging. For this purpose, charging interfaces are installed on the power battery boxes for one-to-one charging through ground charging devices. However, when a train is equipped with multiple power battery boxes, some limitations arise. If only one ground charging device is configured, it is necessary to wait for one battery to be fully charged before starting to charge the next battery, which will extend the charging cycle. Summary of the invention

[0003] The present invention provides a power battery ground charging control method, circuit, power supply system and rail vehicle, which are used to solve the defects of the prior art that the ground charging device can only charge the power battery one by one and the charging cycle is long. The present invention can meet the emergency charging needs of the battery group to be charged, with fast charging speed and low cost.

[0004] The present invention provides a power battery ground charging control method, which is applied to a power battery ground charging circuit of a rail vehicle, wherein the power battery ground charging circuit comprises a main ground charging device and a battery group to be charged; the battery group to be charged comprises at least two power battery groups; the method comprises: obtaining the current voltage value of each power battery group; in the case where there is a voltage difference between the power battery groups, controlling the first charging path to be turned on, and charging the first power battery group 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 group; in the case where the current voltage value of the first power battery group is equal to the current voltage value of the second power battery group, controlling the second charging path to be turned on, and charging the first power battery group and the second power battery group at the same time 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 group; the first power battery group is a power battery group with a lower current voltage value, and the second power battery group is a power battery group with a higher current voltage value; the first charging path and the second charging path are connected in parallel.

[0005] According to a power battery ground charging control method provided by the present invention, before obtaining the current voltage value of each power battery group, it also includes: controlling the power supply path of the battery control unit of each power battery group 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] A power battery ground charging control method provided according to the present invention also includes: monitoring the status of the main ground charging device and the battery group to be charged, and in the event of a fault, determining a charging control strategy according to the fault type.

[0007] According to a power battery ground charging control method provided by the present invention, in the event of a fault, a charging control strategy is determined according to the fault type, including: in the event of a primary fault in the battery pack to be charged, the charging control strategy is to issue a primary fault alarm prompt, and control the charging voltage reduction and current reduction; 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 prompt, and control the charging voltage reduction and current reduction; in the event of a tertiary fault in the battery pack to be charged, the charging control strategy is to issue a tertiary fault alarm prompt, and disconnect the charging of the battery pack to be charged; in the event of a fault in the main ground charging device, the charging control strategy is to issue a device fault alarm prompt, and disconnect the charging of the battery pack to be charged.

[0008] According to a power battery ground charging control method provided by the present invention, the first power supply path includes a coil of a first normally open relay, and 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.

[0009] According to a power battery ground charging control method provided by the present invention, the first charging path includes 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 are closed, the contactor of the first battery control unit is closed, the contactor of the control unit of the main ground charging device is closed, and the first charging path is turned on; when the contacts of the first normally open relay are closed, the contactor of the second battery control unit is closed, and the second charging path is turned on.

[0010] According to a power battery ground charging control method provided by the present invention, 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 of the first battery control unit and the second battery control unit; the charging output end 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 shall not be energized, and the contacts of the second normally open relay shall be disconnected.

[0011] According to a power battery ground charging control method 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 end 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 end of the coil of the second normally open relay.

[0012] According to a power battery ground charging control method 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 the first normally closed relay and a coil of the second normally closed relay; the positive end of the coil of the first normally open relay is respectively connected to the positive end of the coil of the first normally closed relay and one end of the contact of the second normally closed relay, the negative end of the coil of the first normally open relay is respectively connected to the negative end of the coil of the first normally closed relay, the negative end of the coil of the second normally open relay and the negative end of the coil of 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 respectively connected to the positive end of the coil of the second normally open relay and the positive end of the coil of the second normally closed relay.

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

[0014] According to a power battery ground charging control method 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 charging positive and negative poles of the battery group to be charged, the power supply position is the position for connecting the power supply positive and negative poles of the battery control unit of the battery group to be charged, and the communication position is the position for communicating between the battery control unit of the battery group to be charged and the main ground charging device.

[0015] The present invention also provides a power battery ground charging circuit, comprising a main ground charging device and a battery group to be charged; the battery group to be charged comprises at least two power battery groups; the power battery ground charging circuit adopts the above-mentioned power battery ground charging control method for charging control.

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

[0017] The present invention also provides a rail vehicle which adopts the above-mentioned vehicle power supply system for emergency charging.

[0018] The present invention provides a power battery ground charging control method, circuit, power supply system and rail vehicle, which is applied to the power battery ground charging circuit of the rail vehicle, including a main ground charging device and a battery group to be charged; the battery group to be charged includes at least two power battery groups; the method includes: obtaining the current voltage value of each power battery group; in the case of a voltage difference between the power battery groups, controlling the first charging path to be turned on, and charging the first power battery group through the main ground charging device; in the case of the current voltage value of the first power battery group being equal to the current voltage value of the second power battery group, controlling the second charging path to be turned on, and charging the first power battery group and the second power battery group at the same time through the main ground charging device. The present invention can ensure the emergency charging demand of the battery group to be charged, with fast charging speed and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a flow chart of the power battery ground charging control method provided by the present invention.

[0021] Figure 2 It is a specific flow chart of the power battery ground charging control method provided by the present invention.

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

[0023] Figure 4 It is a structural schematic diagram of a 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 structural schematic diagram of the power battery ground charging circuit provided by the present invention.

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

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

[0028] Fig. 9 It is a structural schematic diagram of the ground charging device provided by the present invention. DETAILED DESCRIPTION

[0029] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0030] With the existing overhead line capacity limitation and the need for future off-grid operation, more and more projects are beginning to try to use power batteries to meet the needs of off-grid operation. Power batteries are conventionally charged through overhead lines or fuel cells, but under special working conditions, they need to be charged with a dedicated ground charging device. The power battery box will be equipped with a charging socket, and one-to-one charging is performed through a ground charging device. However, if a train is equipped with multiple boxes of power batteries, it will face limitations. If a charging device is configured, one charging device must be completed before another can be charged, and the charging time is long.

[0031] Please refer to Figure 1 , Figure 1 A schematic flow chart of the power battery ground charging control method provided by the present invention.

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

[0033] The present invention provides a power battery ground charging control method, which is applied to a power battery ground charging circuit of a rail vehicle, wherein the power battery ground charging circuit comprises a main ground charging device and a battery group to be charged; the battery group to be charged comprises at least two power battery groups; The method includes: 101: Obtain the current voltage value of each power battery pack; 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 a charging path between the main ground charging device and the first power battery pack; 103: When the current voltage value of the first power battery group is equal to the current voltage value of the second power battery group, the second charging path is controlled to be turned on, and the first power battery group and the second power battery group 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 group; the first power battery group is a power battery group with a lower current voltage value, and the second power battery group is a power battery group with a higher current voltage value; the first charging path and the second charging path are connected in parallel.

[0034] In order to solve the technical problems existing in the prior art, the present invention provides a power battery ground charging control method to ensure that the power battery pack of the rail vehicle can be charged efficiently and safely. The power battery ground charging circuit of the rail vehicle 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. Each power battery pack contains a number of power battery cells, which are connected in series or in parallel to form the required voltage and capacity. The method of the present invention first obtains the current voltage value of each power battery pack. This can be achieved by connecting a voltage sensor to each battery pack, and the sensor 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 (the message may also include a request charging current value). The control unit of the ground charging device determines the voltage difference between the battery packs.

[0035] When a voltage difference is detected between different power battery packs, the first charging path is controlled to be turned on, which connects the main ground charging device and the first power battery pack with a lower voltage value. At this time, the main ground charging device transmits electric energy to the first power battery pack until its voltage value reaches the preset charging cut-off voltage.

[0036] When the voltage value of the first power battery pack (1# power battery) is equal to that of the second power battery pack (2# power battery) with a higher voltage value, the second charging path is controlled to be turned on, so that the main ground charging device can charge the first power battery pack and the second power battery pack at the same time, and the charging can be interrupted at any time to ensure that the voltage and SOC of each box of power batteries remain consistent. At this time, the first charging path and the second charging path are connected in parallel, allowing the current to be distributed between the two battery packs to balance their voltages.

[0037] Through this control method, when the initial voltage of each power battery is inconsistent, the charging order is automatically identified, which is more intelligent and can ensure that the voltage of the power battery pack of the rail vehicle is balanced during the charging process, avoiding overcharging or undercharging, thereby extending the battery life and improving the charging efficiency. In addition, this method is also flexible and can adapt to power battery packs with different configurations to meet the charging needs of different rail vehicles.

[0038] As a preferred embodiment, before obtaining the current voltage value of each power battery pack, it also includes: controlling the power supply path of the battery control unit of each power battery pack to be turned on, and powering 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.

[0039] In this embodiment, each power 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. BMS is essential to ensure battery safety, extend battery life, and optimize the charging process. Before starting to obtain the voltage value of each power battery pack, the power supply path of the battery control unit of each power battery pack is controlled to be turned on, ensuring that the BMS has been fully supplied with power before voltage monitoring, so that it can accurately perform its monitoring and control functions.

[0040] Specifically, the main ground charger supplies power to the BMS of each power battery pack through a power supply path. This power supply path is a direct connection between the main ground charger and the battery control unit. The conduction of the power supply path can be achieved through a control switch or circuit, which is controlled by the central control unit. Once the power supply path is turned on, the main ground charger provides stable power to the BMS, enabling it to start working.

[0041] The power battery ground charging control method of the present invention can not only ensure that the power battery pack has been effectively monitored by the BMS before charging, but also improve 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 accurate and efficient. In addition, this also helps to promptly detect and deal with any potential battery problems, thereby protecting the battery from damage and ensuring the safe operation of rail vehicles.

[0042] As a preferred embodiment, it also includes: monitoring the status of the main ground charging device and the battery pack to be charged, and in the event of a fault, determining a charging control strategy according to the type of fault.

[0043] In this embodiment, the control unit of the main ground charging device will monitor the status of the main ground charging device, and the battery control unit of the battery pack to be charged will monitor 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 based on preset thresholds and logic.

[0044] When an abnormal situation is detected, such as voltage outside the safe range, abnormal current, high temperature, or the battery pack charging status is not as expected, the fault diagnosis program will be triggered. The fault diagnosis program will determine the specific fault type based on the collected data and the preset fault code library.

[0045] 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 starting the cooling system. If a voltage abnormality is detected, the control strategy may include adjusting the charging voltage or switching to a backup charging path.

[0046] This embodiment increases the flexibility and intelligence of the charging circuit. When a fault occurs, the charging strategy can be automatically adjusted to protect the battery pack and the charging device and reduce the impact of the fault.

[0047] As a preferred embodiment, in the event of a fault, a charging control strategy is determined according to the type of fault, including: in the event of a level one fault in the battery pack to be charged, the charging control strategy is to issue a level one fault alarm and control the charging voltage and current reduction; in the event of a level two fault in the battery pack to be charged, the charging control strategy is to issue a level two fault alarm and control the charging voltage and current reduction; in the event of a level three fault in the battery pack to be charged, the charging control strategy is to issue a level three fault alarm and disconnect the charging of the battery pack to be charged; in the event 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.

[0048] Please refer to Figure 3 , Figure 3 This is a schematic diagram of the fault sub-process provided by the present invention.

[0049] In this embodiment, a hierarchical fault response mechanism is set up, and different control strategies can be executed according to the severity of the fault. The fault is divided into a primary fault, a secondary fault, a tertiary fault, and a main ground charging device fault. Each level of fault corresponds to different alarm prompts and charging control measures.

[0050] When a primary fault occurs in the battery pack to be charged, the charging control strategy executed includes a primary fault alarm flag and controls the charging voltage reduction and current reduction. Voltage reduction means reducing the charging voltage, while current reduction means reducing the charging current. This strategy aims to reduce further damage to the battery pack caused by the fault while trying to maintain the basic charging requirements of the battery.

[0051] When a secondary fault occurs in the battery pack to be charged, the charging control strategy executed includes a primary fault alarm sign, and controls the charging voltage and current reduction, and the alarm is uploaded to the HMI.

[0052] When a level 3 fault occurs in the battery pack to be charged, a more stringent control strategy will be implemented. This includes a level 3 fault alarm flag, complete disconnection of charging of the battery pack to be charged, and alarm upload to the HMI. Level 3 faults usually refer to those situations that may cause serious damage to the battery pack or pose a safety hazard, so charging needs to be stopped immediately to prevent further damage.

[0053] When the main ground charging device fails, an alarm is uploaded to the HMI and the charging of the battery pack to be charged is disconnected. This is because the failure of the main ground charging device may affect the safety and effectiveness of the entire charging process, so charging needs to be stopped immediately to protect the battery pack.

[0054] Afterwards, it is determined whether the contactor of the battery control unit of the battery pack to be charged and the contactor of the control unit of the main ground charging device are disconnected. If the contactor is not disconnected, a shutdown command of the main ground charging device is sent to force a power outage.

[0055] Please refer to Figure 4 , Figure 4 A schematic structural diagram of a rail vehicle provided by the present invention.

[0056] As a preferred embodiment, the first power supply path includes a 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.

[0057] In this embodiment, the first normally open relay is used to control the conduction conditions of the first power supply path and the second power supply path, so as to realize power supply to the battery control units (BMS) of the first power battery pack and the second power battery pack.

[0058] The main ground charging device supplies power to the first battery control unit and the second battery control unit through two independent power supply paths. The two power supply paths are the first power supply path and the second power supply path, which are connected to the BMS of the first power battery pack and the second power battery pack respectively.

[0059] The coil of the first normally open relay is set on 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 turned on, which can ensure that the two BMSs are supplied with power at the same time, so that the status of the two power battery packs can be monitored and managed at the same time. This embodiment improves the safety and reliability of the charging process, and also improves the charging efficiency because it allows the two BMSs to work at the same time, reducing the charging preparation time. In addition, this design also helps to achieve more accurate battery pack voltage balancing during the charging process, thereby extending the battery life and improving the efficiency of the entire charging system.

[0060] As a preferred embodiment, the first charging path includes 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 are closed, the contactor of the first battery control unit is closed, the contactor of the control unit of the main ground charging device is closed, and the first charging path is turned on; when the contacts of the first normally open relay are closed, the contactor of the second battery control unit is closed, and the second charging path is turned on.

[0061] In this embodiment, the normally open relay is an electronic switch, which is disconnected when not powered. When the coil is powered, the contacts of the relay are closed, thereby conducting the circuit. When the main ground charging device supplies power to the coil of the first normally open relay, the coil of the first normally open relay 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 closing of the contactor of the first battery control unit, and the closing of the contactor of the first battery control unit triggers the closing of the contactor of the control unit of the main ground charging device, thereby conducting the first charging path between the first power battery pack and the main ground charging device, ensuring that the electric energy of the main ground charging device can flow to the first power battery pack.

[0062] When the current voltage value of the first power battery pack is equal to the current voltage value of the second power battery pack, the first power battery pack and the second battery pack need to be charged simultaneously. When the contact of the first normally open relay remains in a closed state, the contactor of the second battery control unit will also be closed. Since the contactor of the control unit of the main ground charging device is already in a closed state, this makes the second charging path conductive, allowing the main ground charging device to charge the first power battery pack and the second power battery pack simultaneously.

[0063] As a preferred embodiment, 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 of the first battery control unit and the second battery control unit; the charging output end 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 contacts of the second normally open relay are disconnected.

[0064] In order to ensure that the power battery pack can still obtain the necessary charging when the main ground charging device fails, in this embodiment, first, a first isolation element is added to the first power supply path. The function of this element is to ensure that the power is stably supplied to the first battery control unit when the main ground charging device is working normally. At the same time, a backup ground charging device is introduced, which provides backup power to the first and second battery control units through a backup power supply path. This backup power supply path includes a second isolation element and a coil of a second normally open relay.

[0065] The charging output end 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. In this way, when the main ground charging device fails to work, the backup ground charging device can supply power to the second charging path through the contact of the second normally open relay to ensure that the second power battery pack can continue to charge.

[0066] The first isolation element is connected to the second isolation element, which means that when the first isolation element is energized, the second isolation element will not be energized, thereby ensuring that the coil of the second normally open relay is also not energized, causing the contacts of the second normally open relay to remain in an open state. This design ensures that the backup ground charging device will not intervene when the main ground charging device is working normally, and the backup ground charging device will only be activated when the main ground charging device fails.

[0067] 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 obtain the necessary charge when the main ground charging device fails, thereby ensuring the continuous operation capability of the rail vehicle. This redundant design is crucial to improving the stability and reliability of the entire charging system, especially in critical transportation systems, ensuring the continuity and reliability of services.

[0068] As 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 end 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 end of the coil of the second normally open relay.

[0069] 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.

[0070] In this embodiment, the control of the main ground charging device and the backup ground charging device is realized by using the first diode and the second diode as isolation elements. The first isolation element is the first diode, and the second isolation element is the second diode. The diode is an electronic component that allows current to flow in only one direction, and has an anode and a cathode. In this embodiment, the anode of the first diode is connected to the positive end of the coil of the first normally open relay, and 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 end of the coil of the second normally open relay. This connection method ensures that when the first diode is turned on, the current can only flow from the first normally open relay to the second diode, but not in the reverse direction. This means that when the main ground charging device is working normally, the first diode is turned on, so that the coil of the first normally open relay is energized, thereby controlling the first power supply path and the first charging path. At this time, the second diode prevents the current from flowing to the coil of the second normally open relay due to reverse bias, ensuring that the contacts of the second normally open relay remain in an open state, thereby avoiding the intervention of the backup ground charging device.

[0071] In this embodiment, when the main ground charging device fails, the first diode will be cut off, allowing current to flow to the second diode and the coil of 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.

[0072] As a preferred embodiment, 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 end of the coil of the first normally open relay is respectively connected to the positive end of the coil of the first normally closed relay and one end of the contact of the second normally closed relay, the negative end of the coil of the first normally open relay is respectively connected to the negative end of the coil of the first normally closed relay, the negative end of the coil of the second normally open relay and the negative end of the coil of 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 respectively connected to the positive end of the coil of the second normally open relay and the positive end of the coil of the second normally closed relay.

[0073] Please refer to Figure 6 , Figure 6 This is the second structural schematic diagram of the power battery ground charging circuit provided by the present invention.

[0074] In this embodiment, 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. This design utilizes the characteristics of relays, wherein the contacts of the normally closed relay are closed when not powered, and the contacts of the normally open relay are open when not powered. In this configuration, the positive end of the coil of the first normally open relay is connected to the positive end of the coil of the first normally closed relay and one end of the contact of the second normally closed relay, respectively, and the negative end of the coil of the first normally open relay is connected to the negative end of the coil of the first normally closed relay, the negative end of the coil of the second normally open relay, and the negative end of the coil of the second normally closed relay, respectively. Such a connection ensures that when the ground charging device is in working condition, 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, and the contact KM1 of the first normally open relay is closed, thereby connecting the first charging path and the second charging path.

[0075] 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 end of the coil of the second normally open relay and the positive end of the coil of the second normally closed relay respectively. This design ensures that when the main ground charging device is working, the contact KM3 of the first normally closed relay is disconnected, 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 is kept disconnected, thereby blocking the power supply path of the backup ground charging device.

[0076] As a preferred embodiment, the emergency charging socket of the rail vehicle is arranged at a preset position under the body of the rail vehicle; the main ground charging device performs emergency charging on the battery pack to be charged through the emergency charging socket.

[0077] In this embodiment, the emergency charging socket of the rail vehicle is set to be installed at a preset position under the vehicle body, so that there is no need to climb to the top for emergency charging. The selection of this preset position takes into account the dynamic characteristics, safety and convenience of the vehicle charging operation. The emergency charging socket is designed to be able to connect and disconnect quickly so as to quickly provide power to the power battery pack of the rail vehicle in an emergency.

[0078] The emergency charging socket includes the necessary electrical connection terminals and sealing mechanisms to ensure that it is not affected by environmental factors such as dust and moisture when the vehicle is running, while safely transmitting power during the charging process. The socket is also designed for mechanical strength and durability to withstand the wear and stress of daily operation.

[0079] In the event that emergency charging is required, the main ground charging unit is connected to the emergency charging socket via a special charging cable that is designed to withstand high currents and voltages while being flexible enough to accommodate different charging positions and angles.

[0080] The number of emergency charging sockets can be flexibly set according to the type of train, for example, one is set on each side of the train, and the present invention does not make any special limitation here.

[0081] This embodiment improves the emergency response capability of the charging circuit. In an emergency, the rail vehicle can quickly obtain electrical energy through the emergency charging socket, ensuring the continuous operation of the vehicle and uninterrupted service.

[0082] As a preferred embodiment, 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 charging poles of the battery pack to be charged, the power supply position is the position for connecting the positive and negative power supply poles of the battery control unit of the battery pack to be charged, and the communication position is the position for communicating between the battery control unit of the battery pack to be charged and the main ground charging device.

[0083] Please refer to Figure 7 , Figure 7 This is a structural schematic diagram of the emergency charging socket provided by the present invention.

[0084] In this embodiment, the emergency charging socket is a multifunctional interface, which includes three main positions: charging position, power supply position and communication position. These positions are designed to achieve efficient, safe and intelligent charging of the battery pack to be charged in the rail vehicle.

[0085] The charging position is the location in the emergency charging socket for connecting the positive and negative charging poles of the battery pack to be charged. It includes two terminals, corresponding to the positive pole (B) and negative pole (G) of the battery. During the emergency charging process, the main ground charging device provides power to the battery pack to be charged through the charging position for rapid charging. The design of the charging position ensures efficient transmission of power while avoiding the risk of short circuit or overload.

[0086] The power supply position is the location of the positive and negative power supply (D-1, D-2) of the battery control unit (BMS) in the emergency charging socket for connecting the battery pack to be charged. The BMS is a key component for monitoring and managing the 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 that the BMS can continue to work during the charging process.

[0087] The communication bit (D-3, D-4) is the position in the emergency charging socket used to realize the communication between the battery control unit of the battery pack to be charged and the main ground charging device. The communication bit includes the necessary interface and protocol to realize the two-way transmission of data. Through the communication bit, the BMS can send battery status information such as voltage, current, temperature, etc. to the main ground charging device, and the main ground charging device can adjust the charging strategy based on this information.

[0088] For example, the entire train is equipped with 2 boxes of power batteries (the first power battery pack and the second power battery pack) and 2 emergency charging sockets (X1 and X2), which are located on both sides of the train.

[0089] When the power battery is fed, it can be charged by the ground charging device through the emergency charging socket, and two boxes of power batteries can be charged in parallel. A+ and A- are DC24V positive and negative respectively, and there is a relay coil between A+ and A-, and the corresponding contacts are driven by 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, and the power battery control unit BMS communicates with the ground charging device. The coil of the first normally open relay between A1+ and A1- on this side is energized, and the contact KM1 of the first normally open relay is closed. After completing the status confirmation, each box of 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, inputs high voltage electricity, and charges the power battery. On the other side, because the D2 diode 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 disconnected, that is, X2 is not energized, to prevent people from accidentally touching X2 and being shocked, and to protect personal safety.

[0090] Please refer to Figure 8 , Figure 8 This is a schematic diagram of the structure of the power battery pack provided by the present invention.

[0091] In addition, the structure of the power battery pack may include a battery module, a fuse (FU1, FU2), a main contactor (K1, K2), a pre-charge contactor (K3), an emergency charging contactor (K4), a voltage sensor, a current sensor, a maintenance switch (MSD), etc. The power battery is equipped with an emergency charging interface (battery charging positive, battery charging negative), and the power battery can be charged through a ground charging device, which is not particularly limited in the present invention.

[0092] Please refer to Fig. 9 , Fig. 9 This is a schematic structural diagram of the ground charging device provided by the present invention.

[0093] The ground charging device may include an in-garage power supply (380V), an AD / DC module, a contactor, etc., and the present invention does not make any special limitation here.

[0094] 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 referenced to each other.

[0095] The present invention also provides a power battery ground charging circuit, comprising a main ground charging device and a battery group to be charged; the battery group to be charged comprises at least two power battery groups; the power battery ground charging circuit adopts the above-mentioned power battery ground charging control method for charging control.

[0096] The vehicle power supply system provided by the present invention is described below. The vehicle power supply system described below and the power battery ground charging method described above can be referenced to each other.

[0097] The present invention also provides a vehicle power supply system, comprising the above-mentioned power battery ground charging circuit.

[0098] The rail vehicle provided by the present invention is described below. The rail vehicle described below and the power battery ground charging method described above can be referenced to each other.

[0099] The present invention also provides a rail vehicle which adopts the above-mentioned vehicle power supply system for emergency charging.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A power battery ground charging control method, characterized in that: A power battery ground charging circuit applied to a rail vehicle, the power battery ground charging circuit comprising 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: Get the current voltage value of each power battery pack; In the case where 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 value of the first power battery group is equal to the current voltage value of the second power battery group, the second charging path is controlled to be turned on, and the first power battery group and the second power battery group 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 group; the first power battery group is a power battery group with a lower current voltage value, and the second power battery group is a power battery group with a higher current voltage value; the first charging path and the second charging path are connected in parallel.

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 method further includes: The power supply path of the battery control unit of each power battery pack is controlled to be turned on, and the battery control unit is powered by the main ground charging device; 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 are 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 a charging control strategy according to the type of fault includes: In the case of a primary fault occurring in the battery pack to be charged, the charging control strategy is to issue a primary fault alarm and control the charging voltage and current reduction; In the event of a secondary fault occurring in the battery pack to be charged, the charging control strategy is to issue a secondary fault alarm and control charging voltage and current reduction; In the case where a third-level fault occurs in the battery pack to be charged, the charging control strategy is to issue a third-level fault alarm prompt and disconnect the charging of the battery pack to be charged; In the event of a failure of the main ground charging device, the charging control strategy is to issue a device failure 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 power supply path includes a 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 a power supply path for a first battery control unit, and the second power supply path is a power supply path for a second battery control unit; The first battery control unit is a battery control unit of the first power battery pack, and the second battery control unit is a battery control unit of the second power battery pack.

6. The power battery ground charging control method according to claim 5, characterized in that: The first charging path includes contacts 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 is closed, the contactor of the first battery control unit is closed, the contactor of the control unit of the main ground charging device is closed, and the first charging path is turned on; When the contact of the first normally open relay is closed, the contactor of the second battery control unit is closed, and the second charging path is turned on.

7. The power battery ground charging control method according to claim 6, 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 a backup power supply path for the first battery control unit and the second battery control unit; The charging output end 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 isolating element is energized, the second isolating element and the coil of the second normally open relay are de-energized, and the contacts of the second normally open relay are opened.

8. The power battery ground charging control method according to claim 7, 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 end 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 end of the coil of the second normally open relay.

9. The power battery ground charging control method according to claim 7, characterized in that: 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 the first normally closed relay and a coil of the second normally closed relay; The positive end of the coil of the first normally open relay is respectively connected to the positive end of the coil of the first normally closed relay and one end of the contact of the second normally closed relay, the negative end of the coil of the first normally open relay is respectively connected to the negative end of the coil of the first normally closed relay, the negative end of the coil of the second normally open relay and the negative end of the coil of 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 respectively connected to the positive end of the coil of the second normally open relay and the positive end of the coil of the second normally closed relay.

10. The power battery ground charging control method according to any one of claims 1 to 9, characterized in that: The emergency charging socket of the rail vehicle is arranged at a preset position below the body of the rail vehicle; the main ground charging device performs emergency charging on the battery pack to be charged through the emergency charging socket.

11. The power battery ground charging control method according to claim 10, characterized in that: 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 charging poles of the battery group to be charged, the power supply position is the position for connecting the positive and negative power supply poles of the battery control unit of the battery group to be charged, and the communication position is the position for communicating between the battery control unit of the battery group to be charged and the main ground charging device.

12. A power battery ground charging circuit, characterized in that: It comprises a main ground charging device and a battery group to be charged; the battery group to be charged comprises at least two power battery groups; the power battery ground charging circuit adopts the power battery ground charging control method described in any one of claims 1 to 11 for charging control.

13. A vehicle power supply system, characterized in that: Including the power battery ground charging circuit as described in claim 12.

14. A rail vehicle, characterized in that: The vehicle power supply system according to claim 13 is used for emergency charging.

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