A new lithium battery charging and discharging system and method for unmanned vehicles

Abstract

The application discloses a novel lithium battery charging and discharging system and method for unmanned vehicles, which comprises a lithium battery pack, a lithium battery discharging module, a lithium battery charging module, a lithium battery power management module and a lithium battery communication interface, wherein the lithium battery pack is electrically connected with the lithium battery discharging module, the lithium battery charging module and the lithium battery power management module respectively, the lithium battery power management module is electrically connected with the lithium battery discharging module, the lithium battery charging module and the lithium battery communication interface, the lithium battery power management module comprises a main board BMS and a slave board BMU, the main board BMS is electrically connected with the slave board BMU, a plurality of groups of pins are arranged on the main board BMS and connected to the battery communication interface respectively. The lithium battery unmanned vehicle type is matched, no fault occurs in operation, and the possibility of operation is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium batteries, and in particular relates to a novel lithium battery charging and discharging system and charging and discharging method for unmanned vehicles. Background Art

[0002] Due to the advantages of lithium battery systems such as long cycle life and light weight, more and more vehicles are using lithium battery systems. At present, the fault handling of autonomous driving lithium batteries is unreasonable, and battery faults cannot be handled normally. In addition, most batteries do not have extreme faults. When charging in the power-on state, the charging will end after one time and will not be recharged. Usually, the battery cannot be fully charged, resulting in a poor user experience.

[0003] This patent discloses a new lithium battery charging and discharging strategy for unmanned vehicles, which solves the matching of lithium battery unmanned vehicle models, making it possible to operate without any failures during operation. Summary of the Invention

[0004] In order to make up for the deficiencies of the prior art, the present invention provides a novel method for charging and discharging a lithium battery for an unmanned vehicle.

[0005] The novel lithium battery charging and discharging system for unmanned vehicles includes a lithium battery pack, a lithium battery discharge module, a lithium battery charging module, a lithium battery power management module and a lithium battery communication interface. The lithium battery pack is electrically connected to the lithium battery discharge module, the lithium battery charging module and the lithium battery power management module respectively. The lithium battery power management module is electrically connected to the lithium battery discharge module, the lithium battery charging module and the lithium battery communication interface. The lithium battery power management module includes a main board BMS and a slave board BMU. The main board BMS is electrically connected to the slave board BMU. The main board BMS is provided with multiple groups of pins, which are respectively connected to the battery communication interface.

[0006] Furthermore, the lithium battery discharge module includes a motor, a motor controller, a pre-charge branch circuit, a discharge relay K2, a main negative relay K3, a shunt FL1 and a fuse F1, wherein the motor controller is electrically connected to the battery communication interface, the motor is connected to the motor controller, one end of the fuse F1 is connected to the lithium battery pack, and the other end is connected to the discharge relay K2, the discharge relay K2 is connected to the motor controller, and the pre-charge circuit is arranged in parallel with the discharge relay K2.

[0007] Furthermore, the pre-charging branch circuit includes a pre-charging resistor R1 and a pre-charging relay K1, one end of the pre-charging resistor R1 is connected to the fuse F1, and the other end is connected to the motor controller through the pre-charging relay K1;

[0008] One end of the shunt FL1 is connected to the lithium battery pack, and the other end is connected to the main negative relay K3.

[0009] Furthermore, the discharge relay K2 is a load positive relay, and the main negative relay K3 is a load negative relay.

[0010] Furthermore, the lithium battery charging module includes a charging port and a slow charging charger, and the charging port is electrically connected to the slow charging charger and the lithium battery communication interface respectively.

[0011] Furthermore, the positive charging port of the slow charging charger is connected to the discharge relay K2, and the negative charging port of the slow charging charger is connected to the main negative relay K3.

[0012] Furthermore, the lithium battery communication interface is a low-voltage interface.

[0013] A novel method for charging and discharging a lithium battery for an unmanned vehicle comprises the following steps:

[0014] S1 charging, connect the charging dock, activate the BMS when the CP end of the mainboard BMS is normally powered, and after activation, the BMS will detect the CC and the charging message and enter the charging mode;

[0015] S2 discharges, closes the key switch, and performs self-test until it receives the power-on command and starts pre-charging;

[0016] If a fault occurs during the self-test process of S21, the fault level and corresponding fault code will be reported according to the three-level fault processing, and the vehicle power-off command will be received;

[0017] If the self-test in S22 is successful, no fault will be reported, and the vehicle will receive the power-on command and enter the pre-charging process;

[0018] During the S221 pre-charging process, the pre-charging status is determined based on the voltage change within 3S. If the pre-charging fails, the corresponding pre-charging fault is determined and reported, including pre-charging circuit fault and pre-charging failure fault.

[0019] After S23 pre-charge is successful, the discharge relay K2 is immediately closed, and the pre-charge relay K1 is disconnected after 1S, completing the entire power-on process;

[0020] S3 is charged again after discharge. When the CC signal is detected, the BMS enters the pre-charge process, closes the charging power control switch S2, and charges after confirming the charging process;

[0021] If the battery is in the powered-on state before charging, S31 keeps the discharge relay K2 and the main negative relay K3 in place after charging, and reports the charging enable state;

[0022] If the battery is fully charged or a serious fault occurs that requires charging to be stopped, the requested current is 0, and if the current is within 2A, charging is stopped.

[0023] After S4 is finished charging, repeat the above S3. Step S3 can be repeated for 2 times. If a serious fault occurs 3 times in a single plug-in, charging is no longer allowed.

[0024] S5 disconnects the charging gun and enters the normal discharge state.

[0025] Furthermore, the step S23 further includes the following steps:

[0026] If a level 1 fault occurs during normal operation after power-on, S231 will only report the fault. If a level 2 fault occurs, the discharge current will be reduced to 1 / 2 of the MAP table while reporting the fault. If a level 3 fault occurs, the corresponding fault and fault level will be reported. After the fault is reported, power will be turned off or discharge will be maintained according to the instructions.

[0027] If a critical fault occurs during operation, S232 reports the corresponding fault level and fault code, and shuts down the system immediately or after a period of time.

[0028] If S233 detects that KEY ON is still present during program operation, but the vehicle message disappears, it will report a communication loss fault and handle it according to the third-level fault;

[0029] If it is detected that KEY ON disappears during operation and the vehicle message also disappears, it is considered that a critical fault has occurred and the critical fault is reported.

[0030] Furthermore, the step S32 further includes the following steps:

[0031] The S321 vehicle message indicates that the vehicle needs to continue to be powered on. At this time, the BMS reports the CP connection status and the vehicle stops and cannot move;

[0032] If the CP signal still exists in step S322, when the SOC drops to a certain range, the charging power supply control switch S2 is closed again to resume charging.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] 1. The power-on process is controlled by the vehicle message, which enables the vehicle to regulate the entire power supply operation process and be guided by the vehicle, reducing the occurrence of failures in the case of unmanned driving.

[0035] 2. Pre-charge failure has two fault judgments: above and below 10%. This makes it easier to accurately locate the branch fault or the selection fault after the fault occurs, which is beneficial for troubleshooting.

[0036] 3. After the occurrence of the third level fault, report to the whole vehicle, give the processing right to the whole vehicle, and promote the intelligence of the unmanned vehicle.

[0037] 4. If the third level fault is recovered, the whole vehicle is instructed to act, the whole vehicle is ensured to be normally operated, and the control of the whole vehicle is increased.

[0038] 5. The relay is still disconnected after the limit fault is recovered, the last protection barrier is added to the battery, and the safety of the battery is ensured.

[0039] 6. The discharge is cut off, the charging is cut off, the discharge relay and the main negative relay are kept static, the whole vehicle is ensured to have power at all times, and the whole discharge and charging process is monitored by the unmanned intelligent system.

[0040] 7. The connection state is still connected after being fully charged, and the continuous charging is allowed three times, if the whole vehicle is always discharged, and the battery power is easily too low when being used if the charging is not performed for a long time, the above problems are avoided by the strategy, and the system running time is increased.

[0041] 8. The disappearance of the KEY ON and the disappearance of the whole vehicle message are two judgment conditions of power-off, and the power-off controllability of the system is increased. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 It is a schematic diagram of the module structure of the application;

[0043] Figure 2 It is a circuit principle diagram of the application;

[0044] Figure 3 It is a method step flow chart of the application. DETAILED DESCRIPTION

[0045] In the description of the application, it should be understood that the terms "one end", "the other end", "outer side", "upper", "inner side", "horizontal", "coaxial", "central", "end", "length", "outer end" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the application.

[0046] The application will be further described below in conjunction with the drawings.

[0047] As Figure 1-2As shown, a novel lithium battery charging and discharging system for unmanned vehicles includes a lithium battery pack 1, a lithium battery discharge module 2, a lithium battery charging module 3, a lithium battery power management module 4 and a lithium battery communication interface 5. The lithium battery pack 1 is electrically connected to the lithium battery discharge module 2, the lithium battery charging module 3 and the lithium battery power management module 4 respectively. The lithium battery power management module 4 is electrically connected to the lithium battery discharge module 2, the lithium battery charging module 3 and the lithium battery communication interface 5. The lithium battery power management module 4 includes a main board BMS and a slave board BMU. The main board BMS is electrically connected to the slave board BMU. The main board BMS is provided with multiple groups of pins, which are respectively connected to the battery communication interface 5.

[0048] The lithium battery discharge module 2 includes a motor, a motor controller, a precharge branch circuit, a discharge relay K2, a main negative relay K3, a shunt FL1, and a fuse F1. The motor controller is electrically connected to the battery communication interface 5, the motor is connected to the motor controller, one end of the fuse F1 is connected to the lithium battery pack 1, and the other end is connected to the discharge relay K2, which is connected to the motor controller. The precharge circuit and discharge relay K2 are arranged in parallel. The lithium battery communication interface 5 is a low-voltage interface.

[0049] The pre-charge branch circuit includes a pre-charge resistor R1 and a pre-charge relay K1. One end of the pre-charge resistor R1 is connected to the fuse F1, and the other end is connected to the motor controller through the pre-charge relay K1; one end of the shunt FL1 is connected to the lithium battery pack 1, and the other end is connected to the main negative relay K3.

[0050] The discharge relay K2 is a load positive relay, and the main negative relay K3 is a load negative relay.

[0051] The lithium battery charging module 3 includes a charging port and a slow charging charger, which are electrically connected to the slow charging charger and the lithium battery communication interface 5. The positive charging port of the slow charging charger is connected to the discharge relay K2, and the negative charging port of the slow charging charger is connected to the main negative relay K3.

[0052] Specifically, for the B1 battery, we currently take the 173 module consisting of 16 lithium iron phosphate batteries in 1 parallel as an example. The number of parallels and the capacity can be increased or decreased. K5 is a charge and discharge relay, which is used to control the opening and closing of the battery's external output, as well as the opening and closing of charging. K1 and R1 form a pre-charge branch to provide corresponding protection for the main relay. K3 is the main negative relay, which is used to cooperate with the discharge relay K2 to control the external output and internal input. The battery management system is master-slave. D1 and D2 are two diodes, so that the charging auxiliary power supply A+ and 12V+ do not affect each other when they power the slave board at the same time. The external motor controller and slow charging charger are connected in parallel outside the positive and negative charging and discharging ports. The slow charging is an AC national standard socket with CAN communication.

[0053] Combine Figure 3 A novel method for charging and discharging a lithium battery for an unmanned vehicle comprises the following steps:

[0054] S1 charging, connect the charging dock, activate the BMS when the CP end of the mainboard BMS is normally powered, and after activation, the BMS will detect the CC and the charging message and enter the charging mode;

[0055] S2 discharges, closes the key switch, and performs self-test until it receives the power-on command and starts pre-charging;

[0056] If a fault occurs during the self-test process of S21, the fault level and corresponding fault code will be reported according to the three-level fault processing, and the vehicle power-off command will be received;

[0057] If the self-test in S22 is successful, no fault will be reported, and the vehicle will receive the power-on command and enter the pre-charging process;

[0058] During the S221 pre-charging process, the pre-charging status is judged based on the voltage change within 3S. If the pre-charging fails, the corresponding pre-charging fault is reported after the fault is judged, including pre-charging circuit fault and pre-charging failure fault. If the vehicle power-on command is received after the self-test is successful, the pre-charging process is entered and the pre-charging relay is closed. If the voltage between the positive load and the negative battery rises to 95% of the battery voltage within 3S, the pre-charging is considered completed. If the voltage does not rise to 95% within 3S, the pre-charging is considered to have failed. If the voltage is below 10% of the battery voltage, it is considered that there is a circuit breaker fault on the pre-charging branch, and the pre-charging circuit fault and pre-charging failure fault are reported at the same time. If the voltage is between 10-95% of the battery voltage, the pre-charging time is too long due to the matching problem between the external capacitor and the pre-charging resistor, and only the pre-charging failure fault is reported.

[0059] After S23 pre-charge is successful, the discharge relay K2 is immediately closed, and the pre-charge relay K1 is disconnected after 1S, completing the entire power-on process;

[0060] S3 is charged again after discharge. When the CC signal is detected, the BMS enters the pre-charge process and closes the charging power control switch S2, so that the charger detects the output A+. The BMS detects A+ and then proceeds to charge after confirming the charging process.

[0061] If the battery is in the powered-on state before charging, S31 keeps the discharge relay K2 and the main negative relay K3 in place after charging, and reports the charging enable state;

[0062] After S32 charging is confirmed, the BMS and the charger exchange messages. The voltage and current output by the charger are the voltages requested by the BMS in the message. If the charger is fully charged or a serious fault occurs that requires charging to be stopped, the requested current is 0. If the current is within 2A, charging is stopped, S2 is disconnected first, and then A+ disappears. After a delay of 1S, the main negative and discharge relays are disconnected;

[0063] After S4 is finished charging, repeat the above S3. Step S3 can be repeated for 2 times. If a serious fault occurs 3 times in a single plug-in, charging is no longer allowed.

[0064] S5 disconnects the charging gun and enters the normal discharge state.

[0065] Step S23 further includes the following steps:

[0066] If a level 1 fault occurs during normal operation of S231 after power-on, only the fault will be reported. If a level 2 fault occurs, the discharge current will be allowed to be reduced to 1 / 2 of the MAP table while reporting the fault. If a level 3 fault occurs, the corresponding fault and fault level will be reported. After the fault is reported, power will be cut off or maintained in discharge according to the instruction. If a power-off instruction is received within 35 seconds, power will be cut off immediately. If no power-off instruction is received within 35 seconds, power will be cut off after 35 seconds. If the fault is recovered within 35 seconds, the fault bit will be cleared and the fault will no longer be reported. If no vehicle power-off instruction is received within 35 seconds, the relay will not be disconnected. If a vehicle power-off instruction is received, the relay will be disconnected.

[0067] If a critical fault occurs during operation of S232, the corresponding fault level and fault code will be reported, and the power will be cut off immediately or after a period of time. If a power-off command is received within 5 seconds, the power will be cut off immediately. If no power-off command is received within 5 seconds, the power will be cut off immediately after 5 seconds. If the fault is recovered within 5 seconds, the fault bit will not be cleared, and the relay will still be disconnected to cut off the power.

[0068] If S233 detects that KEY ON is still present during program operation, but the vehicle message disappears, it will report a communication loss fault and handle it according to the third-level fault;

[0069] If the KEY ON signal is lost during operation and the vehicle message is also lost, a critical fault is detected and reported. Regardless of whether the fault has been resolved, the relay is disconnected after 5 seconds and the system enters sleep mode. If the vehicle message is present but the KEY ON signal is lost, the system reports the KEY ON signal as lost and waits for a vehicle power-off command. If a vehicle power-off command is received within 10 seconds, the system immediately powers off. If no vehicle power-off command is received within 10 seconds, the system powers off after 10 seconds and enters sleep mode.

[0070] Step S32 further includes the following steps:

[0071] S321 whole vehicle message display needs the whole vehicle to continue to power on, at this time the BMS reports the CP connection state, reminding the whole vehicle to charge connection, the whole vehicle stops and cannot move;

[0072] S322 if the CP signal still exists, due to the consumption of the whole vehicle, the SOC must decrease, when the SOC decreases to 80%, close S2 again, make A+ closed, restart charging, and request the corresponding charging current, ensure the output of the charger.

[0073] The power-on process is controlled by the whole vehicle message, which makes the whole vehicle control the operation process of the whole power supply. It is guided by the whole vehicle to reduce the failure rate in the case of unmanned driving. There are two kinds of failure judgments above and below 10% of pre-charge failure, which can accurately locate the branch fault or selection fault after the fault occurs, which is conducive to fault troubleshooting. After the three-level fault occurs, it is reported to the whole vehicle, and the processing power is handed over to the whole vehicle to promote the intelligence of unmanned driving. If the three-level fault is recovered, the whole vehicle will act according to the instructions to ensure that the whole vehicle can operate normally and increase the control of the whole vehicle. After the limit fault is recovered, the relay is still disconnected, which adds the last protective barrier to the battery to ensure the safety of the battery. Discharge to charge and charge to discharge keep the discharge relay and main negative relay unchanged to ensure that the whole vehicle is always powered on, which is convenient for the whole discharge and charge process of the unmanned intelligent system. After being fully charged, it is still connected to allow continuous charging three times. If the whole vehicle is always discharging, the battery power is easy to be too low if it is placed for too long without charging. This strategy avoids the above problems and increases the system running time. The disappearance of KEY ON and the disappearance of the whole vehicle message are two judgment conditions for power-off, which increases the controllability of the system power-off.

[0074] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A novel charging and discharging method for a lithium battery charging and discharging system for an unmanned vehicle, characterized in that: The following steps are involved: S1. Charging: Connect the charging dock and activate the BMS when the CP end of the mainboard BMS is normally powered. After activation, the BMS will detect the CC and the charging message and enter the charging mode. S2, discharge, close the key switch, perform self-test until receiving the power-on command, and start pre-charging; S21. If a fault occurs during the self-test, the fault level and corresponding fault code are reported according to the three-level fault processing, and a vehicle power-off command is received; S22: If the self-test is successful, no fault is reported, and the vehicle receives a power-on command and enters the pre-charging process; S221: During the pre-charging process, the pre-charging status is determined based on the voltage change within 3 seconds. If the pre-charging fails, the corresponding pre-charging fault is determined and reported, including pre-charging circuit fault and pre-charging failure fault. S23: After the pre-charge is successful, the discharge relay K2 is immediately closed, and the pre-charge relay K1 is disconnected after 1 second, completing the entire power-on process; step S23 also includes the following steps: S231. If a level 1 fault occurs during normal operation after power-on, only the fault is reported. If a level 2 fault occurs, the allowed discharge current is reduced to 1 / 2 of the MAP table while the fault is reported. If a level 3 fault occurs, the corresponding fault and fault level are reported. After the fault is reported, power is turned off or discharge is maintained according to the instruction. S232. If a critical fault occurs during operation, the corresponding fault level and fault code are reported, and the power is immediately shut down or completed after a period of time; S233: If it is detected that the KEY ON is still present during program operation, but the vehicle message disappears, a communication loss fault is reported and handled as a level 3 fault. If the KEY ON is detected to be missing during operation and the vehicle message is also missing, it is considered that a critical fault has occurred and will be reported; S3: Recharge after discharge. When the CC signal is detected, the BMS enters the pre-charge process, closes the charging power control switch J2, and then charges after confirming the charging process. S31. If the battery is in the powered-on state before charging, keep the discharge relay K2 and the main negative relay K3 stationary after charging, and report the charging enable state; S32. If the battery is fully charged or a serious fault occurs requiring charging to be stopped, the requested current is 0, and if the current is within 2A, charging is stopped. S321, the vehicle message shows that the vehicle needs to continue to be powered on. At this time, the BMS reports the CP connection status and the vehicle stops and cannot move; S322: If the CP signal still exists, when the SOC drops to a certain range, the charging power control switch J2 is closed again to resume charging; S4: Repeat the above S3 after charging is completed. Step S3 can be repeated for 2 times. If a serious fault occurs 3 times in a single plug-in, charging is no longer allowed. S5. Disconnect the charging gun and enter the normal discharge state.

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