Dual pre-charging circuit

Abstract

The utility model provides a dual pre-charging circuit, which relates to the technical field of electric vehicle batteries and comprises a battery pre-charging module, a vehicle pre-charging module and a pre-charging master control module, and the pre-charging master control module is electrically connected with the battery pre-charging module and the vehicle pre-charging module respectively. The battery pre-charging module comprises a power supply unit, a first pre-charging unit and a protection unit, the positive electrode of the power supply unit is electrically connected with one end of the protection unit, the other end of the protection unit is electrically connected with the vehicle pre-charging module and the pre-charging main control module, and the negative electrode of the power supply unit is electrically connected with one end of the first pre-charging unit; the other end of the first pre-charging unit is electrically connected with the vehicle pre-charging module and the pre-charging main control module; the vehicle pre-charging module comprises a second pre-charging unit and a load unit, one end of the second pre-charging unit is electrically connected with the pre-charging master control module and the protection unit, and the other end of the second pre-charging unit is electrically connected with one end of the first pre-charging unit and the pre-charging master control module through the load unit. According to the utility model, the stability and reliability of the pre-charging process can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of electric vehicle batteries, in particular to a dual pre-charge circuit. Background Art

[0002] At present, with the aggravation of environmental pollution and the deepening of the petrochemical energy crisis, new energy electric vehicles with energy conservation and environmental protection have been developed and popularized. The power battery is the main energy storage source of electric vehicles, especially pure electric vehicles, and the high-voltage relay is a switching device for realizing the energy transmission of the power battery.

[0003] A Chinese patent application with the publication number CN212921140U discloses a multi-load pre-charge circuit, which includes a plurality of loads and a plurality of main relays. The main relays correspond to the loads one by one. The positive electrode of the power battery is connected to one end of the corresponding load through the main relay, and the other end of the load is connected to the negative electrode of the power battery. The pre-charge circuit further includes a pre-charge resistor R and a plurality of pre-charge relays. The pre-charge relays correspond to the loads one by one. The positive electrode of the power battery is connected to one end of the pre-charge resistor R, and the other end of the pre-charge resistor R is respectively connected to each pre-charge relay. Each pre-charge relay is correspondingly connected to one end of a load. However, in the above solution, when the main positive relay at the vehicle end fails due to software and hardware problems and adheres, the pre-charge fails and the circuit is short-circuited. At this time, the main negative relay at the battery end directly bears the impact of the power-on current, which is extremely likely to cause the main negative relay at the battery end to adhere. Therefore, it is very necessary to provide a dual pre-charge circuit to improve the stability and reliability of the pre-charge process. Summary of the Utility Model

[0004] In view of this, the utility model proposes a dual pre-charge circuit. By setting a first pre-charge unit and a second pre-charge unit to respectively limit the current from the power supply unit to the vehicle end and the current from the vehicle end to the load unit during the pre-charge process, the stability and reliability of the entire pre-charge process are improved.

[0005] The utility model provides a dual pre-charge circuit, which includes a battery pre-charge module, a vehicle pre-charge module and a pre-charge main control module. The pre-charge main control module is electrically connected to the battery pre-charge module and the vehicle pre-charge module respectively. Among them,

[0006] The battery pre-charge module includes a power supply unit, a first pre-charge unit and a protection unit. The positive electrode of the power supply unit is electrically connected to one end of the protection unit, and the other end of the protection unit is electrically connected to the vehicle pre-charge module and the pre-charge main control module respectively. The negative electrode of the power supply unit is electrically connected to one end of the first pre-charge unit, and the other end of the first pre-charge unit is electrically connected to the vehicle pre-charge module and the pre-charge main control module. The first pre-charge unit is used to limit the current from the power supply unit to the vehicle end during the pre-charge process;

[0007] The vehicle pre-charge module includes a second pre-charge unit and a load unit. One end of the second pre-charge unit is electrically connected to the pre-charge main control module and the protection unit. The other end of the second pre-charge unit is electrically connected to one end of the first pre-charge unit and the pre-charge main control module through the load unit. The second pre-charge unit is used to limit the current from the vehicle end to the load unit during the pre-charge process.

[0008] Based on the above technical solutions, preferably, the first pre-charge unit includes a main negative relay, a first pre-charge relay, and a first pre-charge resistor. One end of the main negative relay is electrically connected to the negative pole of the power supply unit and one end of the first pre-charge relay respectively. The other end of the main negative relay is electrically connected to one end of the first pre-charge resistor, the pre-charge main control module, and the load unit respectively. The other end of the first pre-charge relay is electrically connected to the other end of the first pre-charge resistor.

[0009] Based on the above technical solutions, preferably, the second pre-charge unit includes a main positive relay, a second pre-charge relay, and a second pre-charge resistor. One end of the main positive relay is electrically connected to one end of the second pre-charge relay, the pre-charge main control module, and the protection unit respectively. The other end of the main positive relay is electrically connected to one end of the second pre-charge resistor and the load unit respectively. The other end of the second pre-charge relay is electrically connected to the other end of the second pre-charge resistor.

[0010] More preferably, the load unit includes a load capacitor and a motor. The first common end of the load capacitor and the motor is electrically connected to the second pre-charge unit. The second common end of the load capacitor and the motor is electrically connected to the pre-charge main control module and the first pre-charge unit respectively.

[0011] More preferably, the pre-charge main control module includes a positive pole plug-in, a negative pole plug-in, a communication plug-in, a battery management unit, and a vehicle control unit. The positive pole plug-in is electrically connected to one end of the protection unit, one end of the second pre-charge unit, and the communication plug-in respectively. The negative pole plug-in is electrically connected to the other end of the first pre-charge unit, the load unit, and the communication plug-in respectively. The communication plug-in is electrically connected to the battery management unit and the vehicle control unit respectively.

[0012] More preferably, a shunt is electrically connected between the power supply unit and the first pre-charge unit. The shunt is used to provide current information for the battery management unit and the vehicle control unit.

[0013] More preferably, the protection unit includes a main fuse.

[0014] More preferably, the power supply unit includes an electric vehicle battery pack.

[0015] The dual pre-charge circuit provided by the present utility model has the following beneficial effects compared with the prior art:

[0016] (1) By setting the first pre-charge unit and the second pre-charge unit to respectively limit the current from the power supply unit to the vehicle end and the current from the vehicle end to the load unit during the pre-charge process, the impact of instantaneous high current on each device in the pre-charge circuit is reduced, thereby reducing the risk of damage to the electrical components in the dual pre-charge circuit. The first pre-charge unit limits the current from the power supply unit to the vehicle end to prevent too large a current from flowing into the vehicle end to protect the battery and in-vehicle electrical system. The second pre-charge unit limits the current from the vehicle end to the load unit to prevent the load unit from being impacted by too large a current. The dual pre-charge design enables better current control during the pre-charge operation of the system, prevents damage caused by current fluctuations, and improves the stability and reliability of the entire pre-charge process.

[0017] (2) The main negative relay, the first pre-charge relay, and the first pre-charge resistor in the first pre-charge unit jointly achieve fine adjustment and limitation of the current from the power supply unit to the load unit. The main positive relay, the second pre-charge relay, and the second pre-charge resistor in the second pre-charge unit independently control the current from the vehicle end to the load unit. This dual current limitation design helps to better manage the current changes during the pre-charge process, improve the charging efficiency and system stability. The rapid action of the relay can quickly cut off abnormal current to protect the battery and in-vehicle electrical system from damage. The series design of the pre-charge resistor can effectively limit the current rising speed, thereby reducing the voltage impact. The coordinated operation of multiple relays can isolate faults in a timely manner and reduce the risk of fault spread. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 It is a circuit schematic diagram of a dual pre-charge circuit provided by the present utility model.

[0020] Description of the reference numerals: 1. Battery pre-charge module; 2. Vehicle pre-charge module; 3. Pre-charge main control module. Detailed Embodiments

[0021] The following will describe the technical solutions in the embodiments of the present invention in a clear and complete manner in combination with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] The present invention discloses a dual pre-charge circuit. Referring to Figure 1 , the circuit includes a battery pre-charge module 1, a vehicle pre-charge module 2, and a pre-charge main control module 3. The pre-charge main control module 3 is electrically connected to the battery pre-charge module 1 and the vehicle pre-charge module 2 respectively. Among them,

[0023] The battery pre-charge module 1 includes a power supply unit, a first pre-charge unit, and a protection unit. The positive pole of the power supply unit is electrically connected to one end of the protection unit. The other end of the protection unit is electrically connected to the vehicle pre-charge module 2 and the pre-charge main control module 3 respectively. The negative pole of the power supply unit is electrically connected to one end of the first pre-charge unit. The other end of the first pre-charge unit is electrically connected to the vehicle pre-charge module 2 and the pre-charge main control module 3. The first pre-charge unit is used to limit the current from the power supply unit to the vehicle end during the pre-charge process.

[0024] In this embodiment, the first pre-charge unit includes a main negative relay, a first pre-charge relay, and a first pre-charge resistor. One end of the main negative relay is electrically connected to the negative pole of the power supply unit and one end of the first pre-charge relay respectively. The other end of the main negative relay is electrically connected to one end of the first pre-charge resistor, the pre-charge main control module 3, and the load unit respectively. The other end of the first pre-charge relay is electrically connected to the other end of the first pre-charge resistor. A shunt is also electrically connected between the power supply unit and the first pre-charge unit. The shunt is used to provide current information for the battery management unit and the vehicle control unit. The protection unit includes a main fuse. The power supply unit includes an electric vehicle battery pack.

[0025] The vehicle pre-charge module 2 includes a second pre-charge unit and a load unit. One end of the second pre-charge unit is electrically connected to the pre-charge main control module 3 and the protection unit. The other end of the second pre-charge unit is electrically connected to one end of the first pre-charge unit and the pre-charge main control module 3 through the load unit. The second pre-charge unit is used to limit the current from the vehicle end to the load unit during the pre-charge process.

[0026] The second pre-charge unit includes a main positive relay, a second pre-charge relay, and a second pre-charge resistor. One end of the main positive relay is electrically connected to one end of the second pre-charge relay, the pre-charge main control module 3, and the protection unit respectively. The other end of the main positive relay is electrically connected to one end of the second pre-charge resistor and the load unit respectively. The other end of the second pre-charge relay is electrically connected to the other end of the second pre-charge resistor.

[0027] The main negative relay, the first pre-charge relay, and the first pre-charge resistor in the first pre-charge unit jointly achieve fine adjustment and limitation of the current from the power supply unit to the load unit. The main positive relay, the second pre-charge relay, and the second pre-charge resistor in the second pre-charge unit independently control the current from the vehicle end to the load unit. This dual current limitation design helps to better manage the current changes during the pre-charge process, improve the charging efficiency and system stability. The rapid operation of the relay can quickly cut off abnormal current, protecting the battery and in-vehicle electrical system from damage. The series design of the pre-charge resistor can effectively limit the current rising speed, thereby reducing the voltage impact. The coordinated work of multiple relays can isolate faults in a timely manner, reducing the risk of fault spread.

[0028] The load unit includes a load capacitor and a motor. The first common terminal of the load capacitor and the motor is electrically connected to the second pre-charge unit, and the second common terminals of the load capacitor and the motor are respectively electrically connected to the pre-charge main control module 3 and the first pre-charge unit.

[0029] The pre-charge main control module 3 includes a positive plug, a negative plug, a communication plug, a battery management unit, and a vehicle control unit. The positive plug is respectively electrically connected to one end of the protection unit, one end of the second pre-charge unit, and the communication plug. The negative plug is respectively electrically connected to the other end of the first pre-charge unit, the load unit, and the communication plug. The communication plug is respectively electrically connected to the battery management unit and the vehicle control unit.

[0030] By setting the first pre-charge unit and the second pre-charge unit to limit the current from the power supply unit to the vehicle end and the current from the vehicle end to the load unit respectively during the pre-charge process, the impact of instantaneous high current on each device in the pre-charge circuit is reduced, thereby reducing the risk of damage to the electrical components in the dual pre-charge circuit. The first pre-charge unit limits the current from the power supply unit to the vehicle end to avoid too large current flowing into the vehicle end to protect the battery and in-vehicle electrical system. The second pre-charge unit limits the current from the vehicle end to the load unit to prevent the load unit from being impacted by excessive current. The dual pre-charge design enables the system to achieve better current control during the pre-charge operation, preventing damage caused by current fluctuations and improving the stability and reliability of the entire pre-charge process.

[0031] As Figure 1 shown, the pre-charge main control module 3 includes an electric vehicle battery pack BT, a main fuse FR, a shunt RW, a main negative relay KJ1, a pre-charge relay KJ2, and a pre-charge resistor R1. The vehicle pre-charge module 2 includes a main positive relay KJ3, a pre-charge relay KJ4, a pre-charge resistor R2, a load capacitor C, and a motor M. The pre-charge main control module 3 includes a positive plug J1, a negative plug J3, a communication plug J2, a battery management unit BMS, and a vehicle control unit VCU.

[0032] The positive electrode of the electric vehicle battery pack BT is electrically connected to one end of the main fuse FR, and the negative electrode of the electric vehicle battery pack BT is electrically connected to one end of the shunt RW. The other end of the main fuse FR is electrically connected to the positive plug-in connector J1. The other end of the shunt RW is respectively electrically connected to one end of the main negative relay KJ1 and one end of the pre-charge relay KJ2. The other end of the main negative relay KJ1 is respectively electrically connected to one end of the pre-charge resistor R1 and the negative plug-in connector J3. The other end of the pre-charge relay KJ2 is electrically connected to the other end of the pre-charge resistor R1. The positive plug-in connector J1 is respectively electrically connected to one end of the pre-charge relay KJ2, the main positive relay KJ3, and one end of the pre-charge relay KJ4. The communication plug-in connector J2 is respectively electrically connected to the battery management unit BMS and the vehicle control unit VCU. The negative plug-in connector J3 is respectively electrically connected to one end of the load capacitor C and one end of the motor M. The other end of the main positive relay KJ3 is respectively electrically connected to one end of the pre-charge resistor R2, the other end of the load capacitor C, and the other end of the motor M. The other end of the pre-charge relay KJ4 is electrically connected to the other end of the pre-charge resistor R2.

[0033] Further, after adding the pre-charge relay KJ2 to the main negative relay KJ1, before closing the main negative relay KJ1, the pre-charge relay KJ2 can be closed first. If the main positive relay KJ3 is stuck, the busbar will have the voltage of the electric vehicle battery pack BT at this time, and the fault is determined and the power-on process is terminated. If the main positive relay KJ3 is normally disconnected, the main negative relay KJ1 is normally closed, and the pre-charge relay KJ2 is delayed to be disconnected, and the subsequent pre-charge power-on process is normally carried out.

[0034] The specific process is as follows: Wake up the Battery Management System (BMS) and start performing related operations such as self-check. After the BMS self-check is completed and there is no fault, close the pre-charge relay KJ2, detect the voltage of the pre-charge relay KJ2, and determine whether the voltage of the pre-charge relay KJ2 is close to the voltage of the electric vehicle battery pack BT after 1 second. If the voltage of the pre-charge relay KJ2 is close to the voltage of the electric vehicle battery pack BT, report a bus voltage abnormal fault to the BMS and end the charging process; if the voltage of the pre-charge relay KJ2 is not close to the voltage of the electric vehicle battery pack BT, close the main negative relay KJ1 and delay turning off the pre-charge relay KJ2; after the vehicle control unit (VCU) confirms that the main negative relay KJ1 is closed, start pre-charging the vehicle end, control the pre-charge relay KJ4 to pull in. If the VCU confirms that the voltage across the pre-charge relay KJ4 does not reach more than 95% of the total voltage of the electric vehicle battery pack BT within 1 second, report a pre-charge fault to the VCU and end the charging process; if the VCU confirms that the voltage across the pre-charge relay KJ4 reaches more than 95% of the total voltage of the electric vehicle battery pack BT within 1 second, confirm that the pre-charge is completed and close the main positive relay KJ3 through the VCU, and delay turning off the pre-charge relay KJ4, and the pre-charge and power-on are completed.

[0035] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A dual pre-charge circuit, characterized in that It includes a battery pre-charging module (1), a vehicle pre-charging module (2), and a pre-charging main control module (3). The pre-charging main control module (3) is electrically connected to the battery pre-charging module (1) and the vehicle pre-charging module (2) respectively. Among them, the battery pre-charging module (1) includes a power supply unit, a first pre-charging unit, and a protection unit. The positive electrode of the power supply unit is electrically connected to one end of the protection unit. The other end of the protection unit is electrically connected to the vehicle pre-charging module (2) and the pre-charging main control module (3) respectively. The negative electrode of the power supply unit is electrically connected to one end of the first pre-charging unit. The other end of the first pre-charging unit is electrically connected to the vehicle pre-charging module (2) and the pre-charging main control module (3). The first pre-charging unit is used to limit the current from the power supply unit to the vehicle end during the pre-charging process; the vehicle pre-charging module (2) includes a second pre-charging unit and a load unit. One end of the second pre-charging unit is electrically connected to the pre-charging main control module (3) and the protection unit. The other end of the second pre-charging unit is electrically connected to one end of the first pre-charging unit and the pre-charging main control module (3) through the load unit. The second pre-charging unit is used to limit the current from the vehicle end to the load unit during the pre-charging process.

2. The dual pre-charging circuit according to claim 1, wherein The first pre-charging unit includes a main negative relay, a first pre-charging relay, and a first pre-charging resistor. One end of the main negative relay is electrically connected to the negative electrode of the power supply unit and one end of the first pre-charging relay respectively. The other end of the main negative relay is electrically connected to one end of the first pre-charging resistor, the pre-charging main control module (3), and the load unit respectively. The other end of the first pre-charging relay is electrically connected to the other end of the first pre-charging resistor.

3. The dual pre-charge circuit according to claim 1, wherein The second pre-charging unit includes a main positive relay, a second pre-charging relay, and a second pre-charging resistor. One end of the main positive relay is electrically connected to one end of the second pre-charging relay, the pre-charging main control module (3), and the protection unit respectively. The other end of the main positive relay is electrically connected to one end of the second pre-charging resistor and the load unit respectively. The other end of the second pre-charging relay is electrically connected to the other end of the second pre-charging resistor.

4. A dual pre-charge circuit according to claim 1, characterized in that, The load unit includes a load capacitor and a motor. The first common end of the load capacitor and the motor is electrically connected to the second pre-charging unit. The second common end of the load capacitor and the motor is electrically connected to the pre-charging main control module (3) and the first pre-charging unit respectively.

5. The dual precharge circuit according to claim 1, wherein, The pre-charging main control module (3) includes a positive electrode plug, a negative electrode plug, a communication plug, a battery management unit, and a vehicle control unit. The positive electrode plug is electrically connected to one end of the protection unit, one end of the second pre-charging unit, and the communication plug respectively. The negative electrode plug is electrically connected to the other end of the first pre-charging unit, the load unit, and the communication plug respectively. The communication plug is electrically connected to the battery management unit and the vehicle control unit respectively.

6. The dual pre-charge circuit according to claim 5, wherein, A shunt is also electrically connected between the power supply unit and the first pre-charge unit, and the shunt is used to provide current information to the battery management unit and the vehicle control unit.

7. The dual pre-charge circuit according to claim 1, characterized in that, The protection unit includes a main fuse.

8. A dual precharge circuit as claimed in claim 1, wherein, The power supply unit includes an electric vehicle battery pack.

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