Lithium battery low-voltage power supply system and method for shield electric traction locomotive

Abstract

The invention provides a lithium battery low-voltage power supply system and method for a shield electric traction locomotive, and belongs to the technical field of lithium battery systems. The lithium battery low-voltage power supply system comprises a BMS, a switch module, a starting switch, a low-voltage power supply battery, a DC / DC converter and a blocking unit, the starting switch is connected with a keyon pin of the BMS and a positive electrode of the low-voltage power supply battery, and the blocking unit is arranged between the positive electrode of the low-voltage power supply battery and a positive power supply port of the BMS. A negative power supply port of the BMS is connected with a control pin of the DC / DC converter through the switch module, and when the starting switch is closed, the low-voltage power supply battery supplies power to the switch module, so that the switch module is conducted, the control pin of the DC / DC converter is controlled to be conducted with a low level, and therefore the DC / DC converter is controlled to work and supply power to the BMS.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery systems, and in particular to a lithium battery low-voltage power supply system and method for a shield electric traction locomotive. Background Art

[0002] In modern tunnel construction, shield electric traction locomotives are key equipment, and their operational stability and reliability are crucial to the progress and safety of the project. The power supply system of traditional shield electric traction locomotives has many problems, especially in terms of low-voltage power supply, which has become an important factor restricting the improvement of locomotive performance.

[0003] At present, most of the lithium batteries of shield electric traction locomotives refer to the low-voltage power supply scheme of conventional high-voltage lithium batteries, using lead-acid batteries to power the BMS and internal components, and then using DC-DC to convert high voltage into low voltage to charge the lead-acid battery. In this scheme, the lead-acid battery is directly connected to the BMS power supply. When the lithium battery is working, the lead-acid battery is in a continuous charging and discharging process. However, the service life of the lead-acid battery is much lower than that of the lithium battery. Therefore, during the entire use of the lithium battery system, there is no way to avoid replacing the lead-acid battery. The process of replacing the lead-acid battery will inevitably destroy the protection level of the lithium battery system; and the lead-acid battery is more likely to leak and precipitate hydrogen during use. When stored for a long time, the self-discharge rate is greater and it is easier to over-discharge. There is a greater safety risk when it is installed in the lithium battery system. Summary of the invention

[0004] The present invention provides a lithium battery low-voltage power supply system and method for a shield electric traction locomotive, which are used to solve the problems of short battery life and high danger in the prior art.

[0005] In order to achieve the above-mentioned purpose, an embodiment of the present invention provides a lithium battery low-voltage power supply system for a shield electric traction locomotive on one hand, the lithium battery low-voltage power supply system includes a battery management system BMS, a switch module, a start switch, a low-voltage power supply battery, a DC / DC converter, and a blocking unit. The start switch is respectively connected to the keyon pin of the BMS and the positive electrode of the low-voltage power supply battery. The blocking unit is arranged between the positive electrode of the low-voltage power supply battery and the positive power supply port of the BMS. The negative power supply port of the BMS is connected to the control pin of the DC / DC converter through the switch module. When the start switch is closed, the low-voltage power supply battery supplies power to the switch module, so that the switch module is turned on to control the control pin of the DC / DC converter to be turned on with a low level, thereby controlling the DC / DC converter to work and supply power to the BMS.

[0006] Optionally, the starting switch is a double-pole self-resetting switch.

[0007] Optionally, the blocking unit is a reverse diode, which is used to isolate the low-voltage power supply battery from the power supply port of the BMS.

[0008] Optionally, the switch module includes a relay K1 and a normally open switch configured therefor, a relay K2 connected in parallel with the relay K1 and a normally open switch configured therefor. When the start switch is closed, the coil of the relay K1 is powered by the low-voltage power supply battery and is energized. The control pin of the DC / DC converter is connected to a low-level signal to start working, and the output voltage supplies power to the BMS. The keyon pin of the BMS obtains a high-level signal through the start switch. The BMS determines that the lithium battery is activated, closes the relay K2, and keeps the control pin of the DC / DC converter enabled, and the lithium battery enters the power-on process.

[0009] Optionally, the lithium battery low-voltage power supply system is also configured with a national standard charging port for charging and a matching charging relay. The BMS is used to detect the CC2 hardware connection signal of each charging port to determine whether each charging port is safely connected to the charging gun, and when safely connected, determine whether the lithium battery status meets the requirements for charging.

[0010] Optionally, the lithium battery low-voltage power supply system is also configured with an external high-voltage power supply system, and the positive and negative poles of the external high-voltage power supply system are connected to the DC / DC converter.

[0011] On the other hand, the present invention also provides a low-voltage power supply method for a lithium battery, which is applied to the above-mentioned low-voltage power supply system for a lithium battery. The low-voltage power supply method for a lithium battery includes: when a keyon signal is received and the duration of the keyon signal is within a preset time, detecting the CC2 hardware connection signal and the charging communication signal of the charging port, the keyon signal is a high-level signal obtained by the keyon pin of the BMS through the start switch when the start switch is pressed; when the connection signal and the charging communication signal are detected, and the lithium battery status meets the charging requirements, the corresponding charging relay is energized to charge the lithium battery; when the keyon signal disappears, the connection signal disappears or the lithium battery is fully charged, the charging is terminated.

[0012] Optionally, the lithium battery low-voltage power supply method also includes: when the connection signal and the charging communication signal are not detected and the lithium battery status meets the discharge requirements, closing the discharge relay to discharge the lithium battery; and judging whether to end the discharge based on the keyon signal duration.

[0013] Optionally, the end of discharging or the end of charging includes: disconnecting all relays, reporting charging or discharging end information, and delaying power-off and sleep.

[0014] On the other hand, the present invention also provides a shield electric traction locomotive, which includes the above-mentioned lithium battery low-voltage power supply system.

[0015] The present invention provides a lithium battery low-voltage power supply system and method for a shield electric traction locomotive. The present invention uses a barrier unit for isolation, and cooperates with a starting switch, a switch module and a low-voltage, small-capacity lithium battery to utilize DC / DC and an external low-voltage power supply interface to power the entire lithium battery low-voltage control system, which has lower cost, longer life and greater safety. In addition, the present invention adds a total negative relay to the negative electrode to avoid the risk of thermal runaway caused by the adhesion of the heating relay. Through the above method, the present invention establishes an effective lithium battery low-voltage power supply system and method, which achieves safer separation of high and low voltages, lower failure rate of components, simplifies the startup and power-off operation processes, and can intelligently judge the battery status, improve operational convenience and system safety, and comprehensively improve the overall performance and reliability of the low-voltage power supply system of the shield electric traction locomotive. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the prior art description. 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 creative work. In the drawings: Figure 1 It is a schematic diagram of the electrical principle structure of the lithium battery low-voltage power supply system of the present invention; Figure 2 is a flow chart of the lithium battery low voltage power supply method of the present invention; Figure 3 is another flow chart of the lithium battery low voltage power supply method of the present invention; Figure 4 It is a logic flow chart of the lithium battery low voltage power supply method of the present invention; Figure 5 It is another electrical principle structure schematic diagram of the lithium battery low-voltage power supply system of the present invention. DETAILED DESCRIPTION

[0017] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0018] It should be noted that the acquisition, transmission, storage, use, and processing of data in the technical solution of this application are in compliance with the relevant provisions of national laws and regulations. In the embodiments of this application, some existing solutions in the industry such as certain software, components, and models may be mentioned, which should be considered as exemplary. Their purpose is only to illustrate the feasibility of implementing the technical solution of this application, but it does not mean that the applicant has or will necessarily use the solution.

[0019] In modern tunnel construction, shield electric traction locomotives are key equipment, and their operational stability and reliability are crucial to the progress and safety of the project. However, the existing low-voltage power supply system of shield electric traction locomotives has a series of problems in battery performance, charging management, and starting and power-off operations. An innovative technical solution is urgently needed to solve these problems in order to improve the overall performance and reliability of shield electric traction locomotives and meet the growing needs of tunnel construction.

[0020] To address this problem, the present invention provides a lithium battery low-voltage power supply system and method for a shield electric traction locomotive. By adopting lithium batteries to replace traditional lead-acid batteries, the problems of low energy density, slow charging and short life are solved, and the battery life and operating efficiency are improved. At the same time, a total negative relay is added to the negative electrode to avoid the risk of thermal runaway caused by adhesion of the heating relay. It also simplifies the startup and power-off operation process, intelligently judges the battery status, improves operational convenience and system safety, and comprehensively improves the overall performance and reliability of the low-voltage power supply system of the shield electric traction locomotive, and has lower costs and longer life.

[0021] Combine the following Figure 1-Figure 4 The present invention is described in detail.

[0022] Figure 1 It is a schematic diagram of the electrical principle structure of a lithium battery low-voltage power supply system provided in an embodiment of the present invention.

[0023] like Figure 1 As shown, an embodiment of the present invention provides a lithium battery low-voltage power supply system for a shield electric traction locomotive, the lithium battery low-voltage power supply system includes a battery management system BMS, a switch module, a start switch, a low-voltage power supply battery, a DC / DC converter, and a blocking unit. The start switch is respectively connected to the keyon pin of the BMS and the positive electrode of the low-voltage power supply battery. The blocking unit is arranged between the positive electrode of the low-voltage power supply battery and the positive power supply port of the BMS. The negative power supply port of the BMS is connected to the control pin of the DC / DC converter through the switch module. When the start switch is closed, the low-voltage power supply battery supplies power to the switch module, so that the switch module is turned on to control the control pin of the DC / DC converter to be turned on with a low level, thereby controlling the DC / DC converter to work and supply power to the BMS.

[0024] The preferred DC / DC converter of the embodiment of the present invention is a DC / DC converter with a control pin. The operation of the DC / DC converter is controlled by controlling the high and low levels of the control pin of the DC / DC converter. The control pin of the DC / DC converter is a high-impedance pin, and the current when it is turned on is in the micro-ampere level. Therefore, the high and low level relays connected to the controller will not generate a large current shock when working, and this relay will not have the risk of adhesion. When the DC / DC converter is working, it can not only power the BMS but also the low-voltage power supply battery to ensure that the low-voltage power supply battery is always in a state close to full power.

[0025] The preferred starting switch K in the embodiment of the present invention is a double-pole self-resetting switch.

[0026] The double-pole self-resetting switch has two independent circuit paths, that is, two sets of contacts. These two sets of contacts can control two different circuits at the same time or control different parts of the same circuit. In this lithium battery low-voltage power supply system, one set of contacts can be used to send a start signal to the BMS, and the other set of contacts can be used to control the on and off of other auxiliary circuits. The double-pole self-resetting switch can control the power on and off of the lithium battery without other complicated operations, with lower costs and better customer experience.

[0027] Preferably, the blocking unit is a reverse diode D1, which is used to isolate the low-voltage power supply battery from the power supply port of the BMS.

[0028] When the double-pole button switch pops up, the low-voltage power supply battery does not supply power to the BMS. Only when the double-pole button is pressed, the low-voltage power supply battery supplies power to the BMS. Therefore, the low-voltage power supply battery does not need a large capacity, so a lithium battery with a smaller size, smaller capacity and longer life is selected.

[0029] Preferably, the switch module includes a relay K1 and a normally open switch configured therefor, and a relay K2 connected in parallel with the relay K1 and a normally open switch configured therefor.

[0030] When the start switch is closed, the coil of the relay K1 is powered by the low-voltage power supply battery and is energized. The control pin of the DC / DC converter is connected to a low-level signal to start working, and the output voltage supplies power to the BMS. The keyon pin of the BMS obtains a high-level signal through the start switch. The BMS determines that the lithium battery is activated and energizes the relay K2, so that the control pin of the DC / DC converter remains enabled, and the lithium battery enters the power-on process.

[0031] In a preferred embodiment of the present invention, when the start switch is pressed, the relay K1 coil is powered by a low-voltage power supply battery, and the control pin of the DC / DC converter is controlled to be turned on with a low level by the conduction of the K1 relay, thereby controlling the operation of the DC / DC converter. After the DC / DC converter is working, it will directly power the BMS. Among them, the relay K1 only conducts low-level signals, and its signal current is only a few microamperes, so the relay K1 uses a relay with smaller power and current capacity to ensure its longer service life; at the same time, because the power of the relay K1 is very small, the current of the contacts of the start switch when in contact and disconnected is very small, ensuring that the start switch has a longer service life. Therefore, the present invention achieves high and low voltage separation, is safer, and has a lower failure rate of components.

[0032] Preferably, the lithium battery low-voltage power supply system is also configured with a national standard charging port for charging and a matching charging relay. The BMS is used to detect the CC2 hardware connection signal of each charging port to determine whether each charging port is safely connected to the charging gun, and when safely connected, determine whether the lithium battery status meets the requirements for charging.

[0033] In the preferred embodiment of the present invention, since the shield electric traction locomotive is a rail vehicle, national standard charging ports are installed on both sides of the vehicle to facilitate vehicle charging. The present invention detects whether the national standard charging port is plugged in with a charging gun through the hardware detection interface of the BMS. Only when the charging gun is plugged in with a lithium battery will the charging relay K5 of the corresponding charging port be attracted, ensuring that the charging port without a gun is not charged with high voltage, which is safer. In addition, users can freely choose single-gun charging and double-gun charging according to on-site conditions, which is more flexible to use.

[0034] Preferably, the lithium battery low-voltage power supply system is also configured with an external high-voltage power supply system, the positive and negative poles of the external high-voltage power supply system are connected to the DC / DC converter, and the DC / DC converter can convert the external high voltage into a suitable low voltage to power the system.

[0035] like Figure 5 As shown, the external high-voltage power supply system includes a main negative relay K3, a heating film HT and a heating relay K8. The heating relay K8 is connected to the heating film HT and is used to control the on and off of the heating film. The heating film HT is connected to the contact of the main negative relay K3 close to the load end. When the heating relay K8 fails due to adhesion, the main negative relay K3 disconnects the heating circuit.

[0036] The invention adds a total negative relay K3 at the negative pole to meet the dual protection requirements of CE / UL certification, and the heating film is connected to the contact of the total negative relay K3 close to the load end. When the heating relay K8 fails due to adhesion, the heating circuit can be disconnected through the total negative relay K3 with a larger overcurrent, thus avoiding the risk of thermal runaway caused by the adhesion of the heating relay K8.

[0037] Preferably, the BMS is used to: monitor lithium battery operating data, including temperature, current and power; The charging and discharging state of the lithium battery is changed according to the start switch signal and the closing of all relays is controlled.

[0038] BMS can monitor the running number of lithium batteries in real time and receive the start switch K signal, and then switch the charging and discharging state of the lithium battery by changing the energizing state of the relay.

[0039] Preferably, the BMS is also used to: when the lithium battery is charging, when the monitored lithium battery temperature is greater than the allowable charging temperature and less than the optimal operating temperature, turn on the heating relay, and when the monitored lithium battery temperature is less than the allowable charging temperature, disconnect the total negative relay; when the lithium battery is discharging, when the lithium battery temperature is less than the optimal operating temperature, turn on the heating relay, and when the lithium battery temperature reaches the optimal operating temperature, turn off the heating relay.

[0040] For example, when the lithium battery is charging, the optimal operating temperature is, for example, 25 degrees, the allowable charging temperature is, for example, 0 degrees, and the monitored lithium battery temperature is, for example, 10 degrees, the BMS turns on the heating relay K8, energizes the heating film HT to heat the lithium battery, and enters the charging and heating mode; when the monitored lithium battery temperature is, for example, -5 degrees, the BMS disconnects the total negative relay K3 and enters the pure heating mode. When the lithium battery is discharging, the optimal operating temperature is, for example, 20 degrees, and the monitored lithium battery temperature is, for example, 10 degrees, the BMS turns on the heating relay K8 to heat the lithium battery. When the lithium battery is heated to 20 degrees, the BMS disconnects the heating relay K8 and stops heating.

[0041] The heating strategy for charging and heat preservation and the heating strategy for discharging and preheating ensure that the lithium battery cells are in the best condition during use and will not easily trigger the protection of the battery cells, thereby causing sudden power outages in the lithium battery system during use.

[0042] Preferably, the present invention also reserves an external starting power supply interface, and the BMS can also be activated by an external power supply when the built-in low-voltage power supply battery and DC / DC converter are abnormal.

[0043] Figure 2 It is a flow chart of a lithium battery low-voltage power supply method provided in an embodiment of the present invention.

[0044] like Figure 2 As shown, a lithium battery low-voltage power supply method provided by the present invention is applied to the above-mentioned lithium battery low-voltage power supply system, and the lithium battery low-voltage power supply method includes: Step 101, when a keyon signal is received and the duration of the keyon signal is within a preset time, the CC2 hardware connection signal and the charging communication signal of the charging port are detected, wherein the keyon signal is a high level signal obtained by the keyon pin of the BMS through the start switch when the start switch is pressed; Step 102, when the connection signal and the charging communication signal are detected and the lithium battery state meets the charging requirements, the corresponding charging relay is attracted to charge the lithium battery; Step 103, when the keyon signal disappears, the connection signal disappears or the lithium battery is fully charged, the charging is terminated.

[0045] Preferably, in step 101, when the start switch is pressed, the coil of relay K1 is powered by the low-voltage power supply battery and is energized. After relay K1 is energized, the control pin of the DC / DC converter is connected to a low-level signal and starts to work, outputting 24V to power the BMS, and at the same time, the keyon pin of the BMS obtains a high-level signal through the start switch. In this way, when the start switch is pressed, the BMS obtains a 24V power supply and detects a keyon signal. At this time, the BMS determines that the low-voltage power supply battery is activated and immediately energizes relay K2, so that the DC control pin remains enabled, and the lithium battery enters the power-on process.

[0046] In the above process, due to the effect of the reverse diode D1, the low-voltage power supply battery is only used to power K1. When the DC / DC converter starts working, the low-voltage power supply battery is discharged. At this time, the low-voltage power supply battery is in a state of floating charge by the DC / DC converter, and the power is maintained at more than 90%.

[0047] Preferably, in step 102, the BMS determines whether each charging port is securely connected to the charging gun by individually detecting the CC2 hardware connection signal of each charging port, and then turns on the charging relay of the corresponding charging port after the connection is reliable to ensure that the charging interface that is not connected to the charging gun is not powered.

[0048] Preferably, in step 103, it is determined whether the lithium battery is fully charged. Since the lithium battery does not communicate with the vehicle, when a large feedback current appears under a high voltage state, the lithium battery is likely to trigger an overvoltage fault. Therefore, the lithium battery adopts a low-voltage pulse charging scheme. Each time the highest single cell is charged to 3.45V, the charging current is halved and continued to charge, and this is repeated until the current is less than 0.1C. This charging scheme can ensure that the battery voltage will not be very high at the end of battery charging and the power can be kept at a high state.

[0049] like Figure 3 As shown, a lithium battery low-voltage power supply method provided by the present invention also includes: Step 201, when the connection signal and the charging communication signal are not detected and the lithium battery state meets the discharge requirement, the discharge relay K6 is attracted to discharge the lithium battery; Step 202: Determine whether to end the discharge according to the duration of the keyon signal.

[0050] Preferably, judging whether to terminate the discharge according to the duration of the keyon signal includes: if the duration of the keyon signal is greater than a preset time, continuing the discharge; if the duration of the keyon signal is less than the preset time, terminating the discharge.

[0051] In a preferred embodiment of the present invention, when the start switch is pressed, the BMS will detect a keyon high-level signal. When the start switch is continuously pressed for more than a preset time, the BMS will assume that the user needs to power off the lithium battery, and the lithium battery will enter the power-off process. Combined with the power-on steps, a start switch can realize the functions of short-press power-on and long-press power-off.

[0052] For example, Figure 4 As shown, the preset time is, for example, 5 seconds. When the start switch is pressed for more than 5 seconds, that is, the keyon signal lasts for more than 5 seconds, the lithium battery continues to be discharged. When the start switch is pressed for less than 5 seconds, that is, the keyon signal lasts for no more than 5 seconds, the discharge of the lithium battery ends.

[0053] Preferably, the end of discharge or the end of charge includes: disconnecting all relays, reporting the end of charge or discharge information, and delaying power-off and sleep. When the system determines that the charge or discharge is finished, it will automatically disconnect all relays and stop the lithium battery from discharging.

[0054] A low-voltage power supply method for a lithium battery provided by the present invention switches the charging and discharging state through the duration of a keyon signal, detects the CC2 hardware connection signal and the charging communication signal of the charging port, and attracts the corresponding relay to perform the charging and discharging operation. A start switch can realize short-press power-on and long-press power-off, which simplifies the power-on and power-off operation process.

[0055] According to the invention, a lithium battery low-voltage power supply system and method for shield electric traction locomotives is provided, through the blocking unit and the switch module, the low-voltage power supply battery only supplies power to the BMS for a short time, thereby extending the service life of the low-voltage power supply battery, making the high and low voltage separation safer, and the failure rate of components lower. At the same time, relay K1 uses a relay with smaller power and current capacity, which delays its own service life. The power on and off of the lithium battery can be controlled by starting the switch, which simplifies the power on and off process and enhances the user experience. In addition, the hardware detection interface of the BMS is used to detect whether the national standard charging port is plugged in with a charging gun. Only when the charging gun is plugged in with a lithium battery will the charging relay of the corresponding charging port be attracted to ensure that the charging port without a gun is not charged with high voltage electricity, thereby improving the safety of the power supply system.

[0056] On the other hand, the present invention also protects a shield electric traction locomotive, which includes the above-mentioned lithium battery low-voltage power supply system.

[0057] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0058] In addition, the terms "system" and "network" are often used interchangeably in this article. The term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0059] It should be understood that in the embodiment of the present invention, "B corresponding to A" means that B is associated with A, and B can be determined according to A. However, it should also be understood that determining B according to A does not mean determining B only according to A, and B can also be determined according to A and / or other information.

[0060] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0061] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0062] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or it can be an electrical, mechanical or other form of connection.

[0063] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiments of the present invention.

[0064] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0065] Through the description of the above embodiments, it can be clearly understood by those skilled in the art that the present invention can be implemented in hardware, firmware, or a combination thereof. When implemented using software, the above functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein the communication media include any medium that facilitates the transmission of computer programs from one place to another. The storage medium can be any available medium that can be accessed by a computer. Taking this as an example but not limited to: a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of an instruction or data structure and can be accessed by a computer. In addition. Any connection can be appropriately a computer-readable medium. For example, if the software is transmitted from a website, server or other remote source using a coaxial cable, optical fiber cable, twisted pair, digital subscriber line (DSL) or wireless technologies such as infrared, radio and microwave, then the coaxial cable, optical fiber cable, twisted pair, DSL or wireless technologies such as infrared, wireless and microwave are included in the fixing of the medium. As used in the present invention, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and blue-ray disc, wherein disk usually reproduces data magnetically, while disc uses laser to reproduce data optically. The above combination should also be included in the scope of protection of computer-readable media.

[0066] In short, the above is only a preferred embodiment of the technical solution of the present invention, and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A lithium battery low-voltage power supply system for a shield electric traction locomotive, characterized in that: The lithium battery low-voltage power supply system includes a battery management system BMS, a switch module, a start switch, a low-voltage power supply battery, a DC / DC converter, and an isolation unit. The start switch is connected to the keyon pin of the BMS and the positive electrode of the low-voltage power supply battery respectively, the blocking unit is arranged between the positive electrode of the low-voltage power supply battery and the positive power supply port of the BMS, and the negative power supply port of the BMS is connected to the control pin of the DC / DC converter through the switch module. When the start switch is closed, the low-voltage power supply battery supplies power to the switch module, turning on the switch module to control the control pin of the DC / DC converter to be turned on with a low level, thereby controlling the DC / DC converter to work and supply power to the BMS.

2. The lithium battery low-voltage power supply system according to claim 1, characterized in that: The starting switch is a double-pole self-resetting switch.

3. The lithium battery low-voltage power supply system according to claim 1, characterized in that: The blocking unit is a reverse diode, which is used to isolate the low-voltage power supply battery from the power supply port of the BMS.

4. The lithium battery low-voltage power supply system according to claim 1, characterized in that: The switch module includes a relay K1 and a normally open switch configured therein, a relay K2 connected in parallel with the relay K1 and a normally open switch configured therein, When the start switch is closed, the coil of the relay K1 is powered by the low-voltage power supply battery and is pulled in. The control pin of the DC / DC converter is connected to a low-level signal and starts working. The output voltage is used to power the BMS. The keyon pin of the BMS obtains a high-level signal through the start switch, and the BMS determines that the lithium battery is activated, and attracts the relay K2 to keep the control pin of the DC / DC converter enabled, and the lithium battery enters the power-on process.

5. The lithium battery low-voltage power supply system according to claim 1, characterized in that: The lithium battery low-voltage power supply system is also equipped with a national standard charging port for charging and a matching charging relay. The BMS is used to detect the CC2 hardware connection signal of each charging port to determine whether each charging port is safely connected to the charging gun. And when safely connected, determine whether the lithium battery status meets the requirements for charging.

6. The lithium battery low-voltage power supply system according to claim 1, characterized in that: The lithium battery low-voltage power supply system is also configured with an external high-voltage power supply system, and the positive and negative poles of the external high-voltage power supply system are connected to the DC / DC converter.

7. A lithium battery low voltage power supply method, characterized in that: Applicable to the lithium battery low-voltage power supply system according to claims 1-6, the lithium battery low-voltage power supply method comprises: When a keyon signal is received and the duration of the keyon signal is within a preset time, the CC2 hardware connection signal and the charging communication signal of the charging port are detected. The keyon signal is a high-level signal obtained by the keyon pin of the BMS through the start switch when the start switch is pressed; When the connection signal and the charging communication signal are detected, and the lithium battery state meets the charging requirements, the corresponding charging relay is attracted to charge the lithium battery; When the keyon signal disappears, the connection signal disappears, or the lithium battery is fully charged, the charging is terminated.

8. The lithium battery low voltage power supply method according to claim 7, characterized in that: The lithium battery low-voltage power supply method also includes: When the connection signal and the charging communication signal are not detected and the lithium battery state meets the discharge requirement, the discharge relay is attracted to discharge the lithium battery; Determine whether to end the discharge based on the duration of the keyon signal.

9. The lithium battery low voltage power supply method according to claim 8, characterized in that: After the discharge or the charge is terminated, the lithium battery low-voltage power supply method further includes: Disconnect all relays, report the end of charging or discharging, and delay power-off and sleep.

10. A shield electric traction locomotive, characterized in that: The shield electric traction locomotive includes the lithium battery low-voltage power supply system described in any one of claims 1-6.

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