Battery system contactor on-off detection circuit and detection method, battery management system and vehicle

Abstract

The invention discloses a battery system contactor on-off detection circuit and detection method, a battery management system and a vehicle. The detection circuit comprises an acquisition module; the positive electrode end of the detection power supply is connected with the input end of the acquisition module through three contactors. The two contactors are connected in parallel and then connected with a positive port of a main loop of the power battery system; the other contactor is connected with a positive port of a direct-current charging loop of the power battery system; the cathode end of the detection power supply is connected with the input end of the acquisition module, the output end of the driving module is connected with the input end of the acquisition module, and the output end of the acquisition module is connected with the input end of the MCU chip. The negative electrode end of the power battery pack is connected with two additional contactors, and the two additional contactors are connected with the negative electrode port of the power battery system main loop and the negative electrode port of the direct current charging loop; the output end of the MCU chip is connected with the input end of the driving module. The circuit is simple in structure.

Description

Technical Field

[0001] The present invention relates to the technical field of on-off detection of battery system contactors, and in particular to an on-off detection circuit and method for detecting on-off of battery system contactors, a battery management system and a vehicle. Background Art

[0002] At present, multiple high-voltage DC contactors and a battery management system (BMS) are required in the power battery system of electric vehicles. The BMS can control the on and off of the contactors to provide or stop providing DC power to the electric vehicle, or allow or disallow external charging equipment to charge the battery system, etc. After the BMS controls the contactor to be connected or disconnected, the BMS needs to detect whether the corresponding contactor is connected or disconnected as expected. If it is not connected or disconnected as expected, the BMS should send an alarm signal to the electric vehicle as required.

[0003] The current method for BMS to detect the on-off status of contactors is generally to use a high-voltage isolation optocoupler to collect the DC high voltage at the load end of the contactor, and then obtain an analog or level signal that the MCU chip can adapt to after voltage division through a voltage-dividing resistor string. One contactor corresponds to one high-voltage isolation optocoupler and one voltage-dividing resistor string. As the number of contactor applications increases, the number of high-voltage isolation optocouplers and voltage-dividing resistor strings increases accordingly, occupying a large area on the BMS printed circuit board PCB. In addition, the price of high-voltage isolation optocouplers is relatively high, generally more than ten yuan, causing excessive hardware cost pressure on the BMS. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings and defects of the prior art and to provide a battery system contactor on-off detection circuit and detection method, a battery management system and a vehicle, aiming to solve the problem of excessive hardware cost of the existing BMS detection circuit.

[0005] In a first aspect of the present invention, a detection circuit for the on-off of a contactor of a battery system is provided, comprising an acquisition module, a drive module, an MCU chip, and a 5V power supply module for providing a working voltage to the acquisition module and the MCU chip; the positive terminal BatP of the detection power supply is respectively connected to the first pins of contactors RLY1, RLY5 and RLY3, and the input terminals LY5, LY1, and LY3 of the acquisition module are correspondingly connected to the second pins of contactors RLY5, RLY1 and RLY3; the second pin of the contactor RLY1 is connected in series with a pre-charging resistor Rp and then connected in parallel with the second pin of the contactor RLY5, and then connected to the main circuit positive electrode port MainP of the power battery system; the second pin of the contactor RLY3 is connected to the DC charging resistor Rp ... The positive terminal of the power circuit is connected to the DCChgP; the negative terminal of the detection power supply BKP is connected to the input terminal HP of the acquisition module, the output terminals D3, D1, and D5 of the drive module are connected to the corresponding input terminals IN3, IN1, and IN5 of the acquisition module, and the output terminals VP5, VP1, and VP3 of the acquisition module are connected to the corresponding input terminals of the MCU chip; the negative terminal BatN of the power battery pack is connected to the first pin of the contactors RLY2 and RLY4, and the second pins of the contactors RLY2 and RLY4 are respectively connected to the main circuit negative port MainN of the power battery system and the DC charging circuit negative port DCChgN; the output terminals DK5, DK3, and DK1 of the MCU chip are connected to the corresponding input terminals of the drive module.

[0006] Wherein, the acquisition module includes detection switches K1, K3, K5, switches Q1, Q2, Q3, and optocouplers U1, U2, U3; the first pins of the detection switches K5, K1, K3 are connected to the negative terminal BKP of the first battery pack, the second pins of the detection switches K5, K1, K3 are correspondingly connected to the B poles of the switch tubes Q1, Q2, Q3 through resistors R6, R2, R4, the E poles of the switches Q1, Q2, Q3 are respectively connected to the input terminals LY5, LY1, LY3 of the acquisition module, the C poles of the switches Q1, Q2, Q3 are respectively connected to the first pins of the optocouplers U1, U2, U3, the second pins of the optocouplers U1, U2, U3 are connected to the negative terminal BKP of the first battery pack, the fourth pins of the optocouplers U1, U2, U3 are connected, and the third pins of the optocouplers U1, U2, U3 are connected to the output terminals VP5, VP1, VP3 of the acquisition module; the acquisition module The power input terminal VDD of the acquisition module is connected to the output terminals VP5, VP1, and VP3 of the acquisition module. The E poles and B poles of switches Q1, Q2, and Q3 are connected through resistors R11, R22, and R13 respectively; the E poles of switches Q1, Q2, and Q3 are connected to one end of resistors R5, R1, and R3 respectively, and the other end of resistors R5, R1, and R3 are connected as the input terminals LY5, LY1, and LY3 of the acquisition module. The C poles of switches Q1, Q2, and Q3 are connected to the first pins of optical couplers U1, U2, and U3 through resistors R7, R8, and R9 respectively. The power input terminal VDD of the acquisition module is connected to the output terminals VP5, VP1, and VP3 of the acquisition module through resistors R20, R22, and R24 respectively. The third pins of optical couplers U1, U2, and U3 are connected to the output terminals VP5, VP1, and VP3 of the acquisition module through resistors R21, R23, and R25 respectively.

[0007] The detection switches K1, K3 and K5 are relays, and the positive and negative poles of the drive module are connected to the positive and negative poles of the coils of the detection switches K1, K3 and K5 respectively.

[0008] The detection power source is a first battery group of a power battery pack, and the first battery group is a plurality of single cells connected in series in a positive terminal group of a power battery.

[0009] The power input terminal VDD of the acquisition module and the power input terminal Vdd of the MCU chip are connected to the power output terminal of the 5V power module, which is used to connect the voltage and current of the 5V DC power supply.

[0010] The 5V power module input terminal and the DP terminal of the driving module are connected to an external 12V / 24V DC power supply of the power management system BMS.

[0011] Wherein, the 12v / 24v DC power supply is a 12v / 24v storage battery, a power battery or a DC power supply device of a car.

[0012] Among them, the power input terminal VDD of the acquisition module and the power terminal Vdd of the MCU chip are connected to the power output terminal of the 5v power module, which is used to connect the voltage and current of the 5v DC power supply.

[0013] The input end of the 5v power module and the DP end of the driving module are connected to an external 12v / 24v DC power supply of a power management system BMS, and the 12v / 24v DC power supply is a 12v / 24v battery of a car.

[0014] A second aspect of the present invention provides a method for detecting the on-off of a battery system contactor, which is implemented by a detection circuit for detecting the on-off of a battery system contactor and is controlled by BMS software in a battery management system, comprising:

[0015] After the BMS software controls the contactor RLY1, RLY3 or RLY5 to close, the BMS software controls the output terminal DK1, DK3 or DK5 of the MCU chip to output a detection control signal, so that the output terminal D1, D3, D5 of the drive module outputs a 12v / 24v DC power supply, and provides a drive signal for the detection switch K1, K3 or K5 of the acquisition module to close the detection switch K1, K3 or K5. Then, the voltage between the input terminal LY1, LY3, LY5 of the acquisition module and the negative terminal BKP of the first battery pack is equal to the voltage of the first battery pack, that is, there is a detection power supply connected. Input, at this time, the signal of the output terminal VP1, VP3 or VP5 of the acquisition module is low level, and the BMS software determines that the contactor RLY1, RLY3 or RLY5 is closed; at this time, if the signal of the output terminal VP1, VP3 or VP5 of the acquisition module is low level, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is closed, and no fault occurs; if the signal of the output terminal VP1, VP3 or VP5 of the acquisition module is high level, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is not closed, a fault occurs, and the fault is recorded;

[0016] After the BMS software completes the determination of the closed state of the contactor, after a set delay time, the output terminal DK1, DK3 or DK5 of the MCU chip is controlled to output the detection switch K1, K3 or K5 to disconnect the control signal. At this time, if the output terminal VP1, VP3 or VP5 of the acquisition module is at a high level, the BMS software determines that the acquisition module has no fault. If the output terminal DK1, DK3 or DK5 of the acquisition module is not at a high level, the BMS software determines that the acquisition module has a fault.

[0017] When no fault occurs in the acquisition module, the BMS software continues to control the output terminal DK1, DK3 or DK5 of the MCU chip to output the detection switch K1, K3 or K5 closing control signal to close the detection switch K1, K3 or K5. At this time, if the output terminal VP1, VP3 or VP5 of the acquisition module is at a low level, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is closed and no fault occurs, and then keeps the detection switch K1, K3 or K5 in a normally closed state; if the output terminal VP1, VP3 or VP5 of the acquisition module is at a high level, the BMS software determines that the contactor is not closed and a fault occurs, sends a contactor fault alarm signal to the vehicle, and then controls the detection switch K1, K3 or K5 to be disconnected;

[0018] When the acquisition module fails, the BMS sends a contactor fault alarm signal to the vehicle, and at the same time, the BMS software controls the output terminal DK5, DK3 or DK1 of the MCU chip to output a detection switch K1, K3 or K5 disconnection control signal to disconnect the detection switch K1, K3 or K5;

[0019] After the BMS software controls the contactor RLY1, RLY3 or RLY5 to be disconnected, a detection power supply is connected between the input terminal LY1, LY3, LY5 of the acquisition module and the negative terminal BKP of the first battery pack. At this time, if the output signal of the output terminal VP1, VP3 or VP5 of the acquisition module is high, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is disconnected and no fault occurs; if the output signal of the output terminal VP1, VP3 or VP5 of the acquisition module is low, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is not disconnected and a fault occurs;

[0020] After the BMS software completes the judgment on the disconnection state of the contactor RLY1, RLY3 or RLY5, it controls the output terminal DK1, DK3 or DK5 of the MCU chip to output the detection switch K1, K3 and K5 to disconnect the control signal after the set delay time. At this time, if the output terminal VP1, VP3 or VP5 of the acquisition module is at a high level, the BMS software determines that the acquisition module has no fault. If the output terminal VP1, VP3 or VP5 is not at a high level, the BMS software determines that the acquisition module has a fault.

[0021] When no fault occurs in the acquisition module, the BMS software continues to control the output terminal DK5, DK3 or DK1 of the MCU chip to output a closing control signal of the detection switch K1, K3 or K5 to close the detection switch K1, K3 or K5. At this time, if the output terminal VP5, VP3 or VP1 of the acquisition module is at a high level, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is disconnected and no fault occurs, and then controls the MCU chip to output a closing control signal to keep the detection switch K1, K3 or K5 in a normally closed state; if the output terminal VP1, VP3 or VP5 of the acquisition module is at a low level, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is not disconnected and a fault occurs, sends a contactor fault alarm signal to the vehicle, and then controls the detection switch K1, K3 or K5 to be disconnected;

[0022] When the acquisition module fails, the BMS sends a contactor fault alarm signal to the entire vehicle. At the same time, the BMS software controls the output terminal DK1, DK3 or DK5 of the MCU chip to output a detection switch K1, K3 or K5 disconnection control signal to disconnect the detection switch K1, K3 or K5.

[0023] A third aspect of the present invention provides a battery management system, including the detection circuit for detecting the on-off of a battery system contactor, or using the detection method to detect the on-off of a battery system contactor.

[0024] A fourth aspect of the present invention provides a vehicle, comprising the battery management system.

[0025] The detection circuit for detecting the on / off of the contactor of the battery system provided by the present invention has a simple circuit structure, and the components used are all of universal models, which can be realized by domestic devices; low-voltage grade optical couplers are used to replace high-voltage optical couplers and multiple voltage-dividing resistors, thereby reducing hardware costs; and the detection circuit of each contactor is independent and non-coupled. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a first schematic diagram of a detection circuit for the on / off of a battery system contactor of the present invention.

[0027] Figure 2 This is a second schematic diagram of the detection circuit for the on / off of the contactor of the battery system of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] See also Figure 1 , 2As shown, the detection circuit for the on-off of the contactor of the battery system in the present invention includes a first battery pack 10, an acquisition module 100, a drive module 200, an MCU chip 300 and a 5v power module 400, wherein the positive terminal BatP of the first battery pack 10 is connected to the first pin of the contactors RLY1, RLY5 and RLY3 as the positive terminal of the power battery pack, respectively, to provide the acquisition module 100 with a detection power supply for detecting the contactors RLY1, RLY3 and RLY5, and the power supply voltage range is 7v~15.2v.

[0030] The first battery group 10 is a component of the power battery group. The present invention defines four single cells connected in series at the positive end of the power battery group as the first battery group 10. The single cells in the present invention are lithium iron phosphate batteries. In practical applications, the number of single cells connected in series can also be determined according to the system of the single cells.

[0031] It should be noted that in the present application, the number of single cells connected in series in the first battery pack of the power battery pack serving as the detection power source is relatively small. Figure 1 The number of series connections given in the figure is 4, and the number of series connections of single cells can be increased or decreased according to actual applications.

[0032] It should be noted that contactor RLY1 is used to connect the positive terminal BatP of the power battery pack with the positive port MainP of the main circuit of the power battery system in the main circuit of the power battery system; contactor RLY5 is used to connect the positive terminal BatP of the power battery pack with the positive port MainP of the main circuit of the power battery system in the pre-charging circuit of the power battery system; contactor RLY3 is used to connect the positive terminal BatP of the power battery pack with the positive port DCChgP of the DC charging circuit of the power battery system in the DC charging circuit of the power battery system.

[0033] The negative terminal BKP of the first battery pack 10 is connected to the input terminal HP of the acquisition module 100, providing a detection power supply for the acquisition module 100, which is used to detect the on and off states of the contactors RLY1, RLY3 and RLY5, wherein the on state refers to the closing of the contacts of the contactors RLY1, RLY3 or RLY5, and the off state refers to the disconnection of the contacts of the contactors RLY1, RLY3 or RLY5.

[0034] It should be noted that in the power battery system, contactor RLY2 is used to connect the negative terminal BatN of the power battery pack with the negative port MainN of the main circuit of the power battery system in the main circuit of the power battery system; contactor RLY4 is used to connect the negative terminal BatN of the power battery pack with the negative port DCChgN of the DC charging circuit of the power battery system in the DC charging circuit of the power battery system.

[0035] The input terminal LY5 of the acquisition module 100 is respectively connected to the second foot of the contactor RLY5 and the first foot of the pre-charging resistor RP, and is used to connect to the detection power supply (the first battery pack 10) to detect the closing and opening of the contactor RLY5; the input terminal LY1 of the acquisition module 100 is respectively connected to the second foot of the contactor RLY1 and the positive terminal MainP of the main circuit, and is used to connect to the detection power supply (the first battery pack 10) to detect the closing and opening of the contactor RLY1; the input terminal LY3 of the acquisition module 100 is respectively connected to the second foot of the contactor RLY3 and the positive terminal DCChgP of the DC charging circuit, and is used to connect to the detection power supply (the first battery pack 10) to detect the closing and opening of the contactor RLY3; the input terminal IN1 of the acquisition module 100 is connected to the output terminal D1 of the driving module 200, and receives the detection switch driving module output by the driving module 200, and the detection switch driving module is used to control the detection switch K1 of the acquisition module 100 (see Figure 2 ) is closed and opened; the input terminal IN3 of the acquisition module 100 is connected to the output terminal D3 of the driving module 200, and the detection switch driving module receives the output of the driving module 200, and the detection switch driving module is used to control the detection switch K3 of the acquisition module 100 (see Figure 2 ) is turned on and off; the input terminal IN5 of the acquisition module 100 is connected to the output terminal D5 of the driving module 200, and receives the detection switch driving module output by the driving module 200, which is used to control the detection switch K5 of the acquisition module group 100 (see Figure 2 ) is connected and disconnected; the output terminal VP1 of the acquisition module 100 is connected to the input terminal 1 of the MCU chip 300, and the MCU chip 300 outputs a detection signal for the on-off of the contactor RLY1, and the MCU chip 300 determines the on-off state of the contactor RLY1 according to the detection signal; the output terminal VP3 of the acquisition module 100 is connected to the input terminal 3 of the MCU chip 300, and the MCU chip 300 outputs a detection signal for the on-off of the contactor RLY3, and the MCU chip 300 determines the on-off state of the contactor RLY3 according to the detection signal; the output terminal VP5 of the acquisition module 100 is connected to the input terminal 5 of the MCU chip 300, and the MCU chip 300 outputs a detection signal for the on-off of the contactor RLY5, and the MCU chip 300 determines the on-off state of the contactor RLY5 according to the detection signal; the power input terminal VDD of the acquisition module 100 is connected to the power output terminal of the 5v power supply module 400, and is used to receive the voltage and current of the 5v DC power supply.

[0036] The input terminal 1 of the driving module 200 is connected to the output terminal DK1 of the MCU chip 300, and receives the contactor detection control signal output by the MCU chip 300. The contactor detection control signal is used to control whether the driving module 200 outputs the detection switch K1 (see Figure 2) drive signal; the input terminal 3 of the driving module 200 is connected to the output terminal DK3 of the MCU chip 300, and receives the contactor detection control signal output by the MCU chip 300, the detection switch control signal is used to control whether the driving module 200 outputs the detection switch K3 (see Figure 2 ) drive signal; the input terminal 3 of the drive module 200 is connected to the output terminal DK5 of the MCU chip 300, and receives the contactor detection control signal output by the MCU chip 300, which is used to control whether the drive module 200 outputs the detection switch K5 (see Figure 2 ) drive signal; the input terminal DP of the driving module 200 is connected to the external 12v / 24v DC power supply of the BMS, which is used as the detection switch K1, K3 and K5 in the acquisition module 100 (see Figure 2 ) is provided by the driving module 200 to the acquisition module 100.

[0037] It should be noted that when running on a vehicle, the external 12v / 24v DC power supply is generally provided by the car's 12v / 24v battery, while in the BMS debugging phase, a 12v / 24v battery pack can be used as a DC power supply, or a separate DC power supply device can be used.

[0038] The output terminal D1 of the driving module 200 is connected to the input terminal IN1 of the acquisition module 100, and provides a driving module for the detection switch K1 in the acquisition module 100; the output terminal D3 of the driving module 200 is connected to the input terminal IN3 of the acquisition module 100, and provides a driving module for the detection switch K3 in the acquisition module 100; the output terminal D5 of the driving module 200 is connected to the input terminal IN5 of the acquisition module 100, and provides a driving module for the detection switch K5 in the acquisition module 100; the power input terminal Vdd of the MCU chip 300 is connected to the 5v power module 400, which is used to receive 5v DC voltage and current;

[0039] The input terminal 1 of the MCU chip 300 is connected to the output terminal VP1 of the acquisition module 100, and receives the on-off detection signal of the contactor RLY1; the input terminal 3 of the MCU chip 300 is connected to the output terminal VP3 of the acquisition module 100, and receives the on-off detection signal of the contactor RLY3; the input terminal 5 of the MCU chip 300 is connected to the output terminal VP5 of the acquisition module 100, and receives the on-off detection signal of the contactor RLY5; the output terminal DK1 of the MCU chip 300 is connected to the input terminal 1 of the driving module 200, and outputs a control signal for detecting the on-off of the contactor RLY1; the output terminal DK3 of the MCU chip 300 is connected to the input terminal 3 of the driving module 200, and outputs a control signal for detecting the on-off of the contactor RLY3; the output terminal DK5 of the MCU chip 300 is connected to the input terminal 5 of the driving module 200, and outputs a control signal for detecting the on-off of the contactor RLY5.

[0040] It should be noted that the power ground terminal of the MCU chip 300 is connected to the ground terminal of the 5V power module 400.

[0041] It should be noted that the BMS software is stored in the MCU chip 300, and the BMS software includes the correspondence between the on and off states of the contactors RLY1, RLY3 and RLY5 and the output terminals VP1, VP3 and VP5, and also includes control instructions for the on and off of the contactors RLY1, RLY3 and RLY5. The control instructions control the corresponding output ports of the MCU chip 300 to output corresponding signals to control the on and off of the contactors.

[0042] In the present application, the input end of the 5v power module 400 is connected to the external 12v / 24v DC power supply of the BMS, which is generally a 12v / 24v battery of a car; the output end 5v of the 5v power module 400 is respectively connected to the power input end VDD of the acquisition module 100 and the power input end Vdd of the MCU chip 300, to output 5v DC power to them.

[0043] It should be noted that the ground terminal of the DC power output of the 5V power module 400 is respectively connected to the power input ground terminal of the acquisition module 100 and the power input ground terminal of the MCU chip 300, and the actual connection is not drawn in the figure.

[0044] In the present invention, in terms of specific implementation, it should be noted that the driving module 200 uses an existing general technical solution to control the output of a 12v / 24v DC power supply.

[0045] In the present invention, it should be noted that the present invention only uses the 5V DC power supply output by the 5V power supply module 400, and requires the output current to be greater than 1A and the output voltage accuracy to be ≥±1%.

[0046] In the present invention, in terms of specific implementation, it should be noted that the detection chip 400 can apply the currently commonly used microprocessor (MCU chip) brand, series and model, such as the MC9S12XE series chips (such as MC9S12XEP100) produced by NXP, or the S32K series chips (such as S32K244, S32K144, etc.) produced by NXP; if it is necessary to use MCU chips produced by other companies, their performance parameters can be selected with reference to the aforementioned chip series.

[0047] It should be noted that the present invention only applies the detection chip 300 to meet the collection of analog or level signals and can be equipped with embedded BMS software and realize logical judgment.

[0048] See also Figure 1 As shown, the working principle of the detection circuit of the on-off of the battery system contactor of the present invention is as follows:

[0049] After the BMS is connected to the external power supply 12v / 24v, the 5v power supply module outputs 5v power to power the MCU chip 300, and the BMS software stored in the MCU chip 300 controls whether the output terminals DK1, DK3 and DK5 of the MCU chip 300 output the detection switches K1, K3 and K5 in the acquisition module 100 (see Figure 2 ) is a control signal that closes or opens.

[0050] It should be noted that before the BMS is powered on at low voltage, the detection switches K1, K3 and K5 are in an open state; after the BMS is powered on at low voltage, the detection switches K1, K3 and K5 can be set to an open state or a closed state. Below, the present invention takes the example of making the detection switches K1, K3 and K5 open or remain in an open state after the BMS is powered on at low voltage to explain the on-off state detection of the contactor.

[0051] After the BMS is powered on at low voltage, the BMS software controls the detection switches K1, K3 and K5 to remain in an open state; when the BMS software stored in the MCU chip 300 controls the contactor RLY5 to be closed, the BMS software controls the output terminal DK5 of the MCU chip 300 to output a detection control signal, so that the output terminal D5 of the drive module 200 outputs a 12v / 24v DC power supply, and provides a drive signal for the detection switch K5 of the acquisition module 100, so that the detection switch K5 is closed; since the contactor RLY5 is in a closed state, the voltage between the input terminal LY5 of the acquisition module 100 and the negative terminal BKP of the first battery pack is equal to the voltage of the first battery pack 10, that is, the detection power supply is connected. At this time, if the signal of the output terminal VP5 of the acquisition module 100 is at a low level, the BMS software determines that the contactor RLY5 is closed, no fault occurs, and no fault alarm signal is issued; if the signal of the output terminal VP5 of the acquisition module 100 is at a high level, the BMS software determines that the contactor RLY5 is not closed, a fault occurs, and the fault is recorded.

[0052] Similarly, when the BMS software controls the contactor RLY1 to close, the BMS software controls the output terminal DK1 of the MCU chip 300 to output a detection control signal, so that the output terminal D1 of the driving module 200 outputs a 12v / 24v DC power supply, and provides a driving signal for the detection switch K1 of the acquisition module 100, so that the detection switch K1 is closed. Then, the voltage between the input terminal LY1 of the acquisition module 100 and the negative terminal BKP of the first battery pack is equal to the voltage of the first battery pack 10, that is, the detection power supply is connected. At this time, if the signal of the output terminal VP1 of the acquisition module 100 is at a low level, the BMS software determines that the contactor RLY1 is closed, no fault occurs, and no fault alarm signal is issued; if the signal of the output terminal VP1 of the acquisition module 100 is at a high level, the BMS software determines that the contactor RLY1 is disconnected and not closed, a fault occurs, and this fault is recorded.

[0053] Similarly, when the BMS software controls the contactor RLY3 to close, the BMS software controls the output terminal DK3 of the MCU chip 300 to output a detection control signal, so that the output terminal D3 of the driving module 200 outputs a 12v / 24v DC power supply, and provides a driving signal for the detection switch K3 of the acquisition module 100, so that the detection switch K3 is closed, then the voltage between the input terminal LY3 of the acquisition module 100 and the negative terminal BKP of the first battery pack is equal to the voltage of the first battery pack 10, that is, the detection power supply is connected. At this time, if the signal of the output terminal VP3 of the acquisition module 100 is low, the contactor RLY3 of the BMS software is closed, no fault occurs, and no fault alarm signal is issued; if the signal of the output terminal VP3 of the acquisition module 100 is high, the BMS software determines that the contactor RLY3 is not closed, a fault occurs, and the fault is recorded.

[0054] After the BMS software completes the determination of the closed state of the contactor RLY1, RLY3 or RLY5, regardless of whether a contactor fault occurs, after a set delay time, the output terminal DK5, DK3 or DK1 of the MCU chip 300 is controlled to output the detection switches K1, K3 and K5 to disconnect the control signal. At this time, if the output terminal VP5, VP3 or VP1 of the acquisition module 100 is at a high level, the BMS software determines that there is no fault in the acquisition module 100; if the output terminal VP5, VP3 or VP1 is not at a high level, the BMS software determines that there is a fault in the acquisition module 100.

[0055] When no fault occurs in the acquisition module 100, the BMS software continues to control the output terminal DK5, DK3 or DK1 of the MCU chip 300 to output the detection switch K1, K3 or K5 closing control signal to close the detection switch K1, K3 or K5. At this time, if the output terminal VP5, VP3 or VP1 of the acquisition module 100 is at a low level, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is closed and no fault occurs, and then keeps the detection switch K1, K3 or K5 in a normally closed state; if the output terminal VP5, VP3 or VP1 of the acquisition module 100 is at a high level, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is not closed and a fault occurs, sends a contactor fault alarm signal to the entire vehicle, and then controls the detection switch K1, K3 or K5 to be disconnected.

[0056] When the acquisition module 100 fails, the BMS sends a contactor fault alarm signal to the entire vehicle. At the same time, the BMS software controls the output terminal DK5, DK3 or DK1 of the MCU chip 300 to output a detection switch K1, K3 or K5 disconnection control signal to disconnect the detection switch K1, K3 or K5.

[0057] When the BMS software controls the contactor RLY5 to disconnect, there is no detection power supply connected between the input terminal LY5 of the acquisition module 100 and the negative terminal BKP of the first battery pack, and the detection power supply is the first battery pack 10. At this time, if the output signal of the output terminal VP5 of the acquisition module 100 is high, the BMS software determines that the contactor RLY5 is disconnected, no fault occurs, and no fault alarm signal is issued; if the output signal of the output terminal VP5 of the acquisition module 100 is low, the BMS software determines that the contactor RLY5 is not disconnected, a fault occurs, and the fault is recorded.

[0058] Similarly, when the BMS software controls the contactor RLY1 to disconnect, there is no voltage and current of the first battery pack 10 between the input terminal LY1 of the acquisition module 100 and the negative terminal BKP of the first battery pack. At this time, if the signal of the output terminal VP1 of the acquisition module 100 is at a high level, the BMS software determines that the contactor RLY1 is disconnected, no fault occurs, and no fault alarm signal is issued; if the signal of the output terminal VP1 of the acquisition module 100 is at a low level, the BMS software determines that the contactor RLY1 is not disconnected, a fault occurs, and the fault is recorded.

[0059] Similarly, when the BMS software controls the contactor RLY3 to disconnect, there is no voltage and current of the first battery pack 10 between the input terminal LY3 of the acquisition module 100 and the negative terminal BKP of the first battery pack. At this time, if the signal of the output terminal VP3 of the acquisition module 100 is high, the BMS software determines that the contactor RLY3 is disconnected, no fault occurs, and no fault alarm signal is issued; if the signal of the output terminal VP3 of the acquisition module 100 is low, the BMS software determines that the contactor RLY3 is not disconnected, a fault occurs, and the fault is recorded.

[0060] After the BMS software completes the judgment on the disconnection state of the contactor RLY1, RLY3 or RLY5, regardless of whether a contactor fault occurs, after a set delay time, the output terminal DK5, DK3 or DK1 of the MCU chip 300 is controlled to output the detection switches K1, K3 and K5 to disconnect the control signal. At this time, if the output terminal VP5, VP3 or VP1 of the acquisition module 100 is at a high level, the BMS software determines that there is no fault in the acquisition module 100. If the output terminal VP5, VP3 or VP1 is not at a high level, the BMS software determines that there is a fault in the acquisition module 100.

[0061] When no fault occurs in the acquisition module 100, the BMS software continues to control the output terminal DK5, DK3 or DK1 of the MCU chip 300 to output a closing control signal of the detection switch K1, K3 or K5 to close the detection switch K1, K3 or K5. At this time, if the output terminal VP5, VP3 or VP1 of the acquisition module 100 is at a high level, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is disconnected and no fault occurs, and then controls the MCU chip 300 to output a closing control signal to keep the detection switch K1, K3 or K5 in a normally closed state; if the output terminal VP5, VP3 or VP1 of the acquisition module 100 is at a low level, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is not disconnected and a fault occurs, sends a contactor fault alarm signal to the entire vehicle, and then controls the detection switch K1, K3 or K5 to be disconnected.

[0062] When the acquisition module 100 fails, the BMS sends a contactor fault alarm signal to the entire vehicle. At the same time, the BMS software controls the output terminal DK5, DK3 or DK1 of the MCU chip 300 to output a detection switch K1, K3 or K5 disconnection control signal to disconnect the detection switch K1, K3 or K5.

[0063] In the present invention, for specific implementation, see Figure 2The acquisition module 100 includes detection switches K1, K3, K5, resistors R1~R9, resistors R20~R25, switches Q1~Q3, and optocouplers U1~U3, wherein: the first pin of the detection switch K5 is connected to the input terminal HP of the acquisition module 100, the input terminal HP is connected to the negative terminal BKP of the first battery pack, and provides a detection power supply for the contactor RYL5; the second pin of the detection switch K5 is connected to the first pin of the resistor R6; the third pin of the detection switch K5 is connected to the input terminal IN5 of the acquisition module 100, and receives the output of the drive module 200 at the output terminal D5.

[0064] It should be noted that, in specific implementation, the detection switches K1, K3 and K5 use ultra-small small signal relays, and the positive and negative poles of the drive module are connected to the positive and negative poles of the coils of the detection switches K1, K3 and K5 respectively. Figure 2 In the figure, the third pin of the detection switches K1, K3 and K5 is the positive pole of the coil, and the negative pole of the coil is not drawn in the figure.

[0065] In specific implementation, the second pin of the resistor R6 is respectively connected to the second pin of the resistor R11 and the base B of the switch Q1 is connected to the first pin of the resistor R1, which is respectively connected to the second pin of the resistor R5 and the emitter E of the switch Q1; the first pin of the resistor R5 is connected to the input terminal LY5 of the acquisition module 100 and the second pin of the contactor RYL5. When the contactor RLY5 is closed, the input terminal LY5 is connected to the positive terminal BatP of the first battery pack 10 (detection power supply) to connect to the detection power supply; when the contactor RLY5 is disconnected, the input terminal LY5 is disconnected from the positive terminal BatP of the first battery pack 10 (detection power supply) and is not connected to the detection power supply; the collector C of the switch Q1 is connected to the first pin of the resistor R7; the second pin of the resistor R7 is connected to the The first foot of the optocoupler U1; the second foot of the optocoupler U1 is connected to the input terminal HP of the acquisition module 100, and the input terminal HP is connected to the negative terminal BKP of the first battery pack to provide a detection power supply for the contactor RYL5; the third foot of the optocoupler U1 is connected to the second foot of the resistor R21; the fourth foot of the optocoupler U1 is connected to the ground terminal of the acquisition module 100; the first foot of the resistor R21 is connected to the output terminal VP5 of the acquisition module 100, and outputs the on-off detection signal of the contactor RLY5 for the MCU chip 300; the first foot of the resistor R21 is also connected to the second foot of the resistor R20; the first foot of the resistor R20 is connected to the power input terminal VDD of the acquisition module 100, and receives the 5V DC power supply provided by the 5V power supply module; the first foot of the resistor R20 is also connected to the resistor R22 The first pin of the detection switch K1 is connected to the input terminal HP of the acquisition module 100, and the input terminal HP is connected to the negative terminal BKP of the first battery pack to provide a detection power supply for the contactor RYL1; the second pin of the detection switch K1 is connected to the first pin of the resistor R2; the third pin of the detection switch K1 is connected to the input terminal IN1 of the acquisition module 100, and receives the output of the drive module 200 output terminal D1; the second pin of the resistor R2 is respectively connected to the second pin of the resistor R12 and the base B of the switch Q2; the first pin of the resistor R12 is respectively connected to the second pin of the resistor R1 and the emitter E of the switch Q2; the first pin of the resistor R1 is connected to the input terminal LY1 of the acquisition module 100, and connected to the first pin of the contactor RYL1 Pin 2, when the contactor RLY1 is closed, the input terminal LY1 is connected to the positive terminal BatP of the first battery pack 10 (detection power supply), and the detection power supply can be connected; when the contactor RLY1 is disconnected, the input terminal LY1 is disconnected from the positive terminal BatP of the first battery pack 10 (detection power supply), and the detection power supply is not connected; the collector C of the switch Q2 is connected to the first pin of the resistor R8; the second pin of the resistor R8 is connected to the first pin of the optocoupler U2; the second pin of the optocoupler U2 is connected to the input terminal HP of the acquisition module 100, and the input terminal H is connected to the negative terminal BKP of the first battery pack, providing the contactor RYL1 with a detection power supply; the third pin of the optocoupler U2 is connected to the second pin of the resistor R23; the fourth pin of the optocoupler U2 is connected to the ground terminal of the acquisition module 100;The first pin of the resistor R23 is connected to the output terminal VP1 of the acquisition module 100, and outputs the on-off detection signal of the contactor RLY1 for the MCU chip 300; the first pin of the detection switch K3 is connected to the input terminal HP of the acquisition module 100, and the input terminal HP is connected to the negative terminal BKP of the first battery pack to provide a detection power supply for the contactor RYL3; the second pin of the detection switch K3 is connected to the first pin of the resistor R4; the third pin of the detection switch K3 is connected to the input terminal IN3 of the acquisition module 100, and receives the drive module output from the output terminal D3 of the drive module 200; the second pin of the resistor R4 is respectively connected to the second pin of the resistor R13 and the base B of the switch Q3; the first pin of the resistor R13 is respectively connected to the second pin of the resistor R3 and the emitter E of the switch Q3; the first pin of the resistor R3 is connected to the input terminal LY3 of the acquisition module 100, and is connected to the second pin of the contactor RYL3. When the contactor RL When Y3 is closed, the input terminal LY31 is connected to the positive terminal BatP of the first battery pack 10 (detection power supply), and the detection power supply can be connected; when the contactor RLY3 is disconnected, the input terminal LY3 is disconnected from the positive terminal BatP of the first battery pack 10 (detection power supply), and the detection power supply is not connected; the collector C of the switch Q3 is connected to the first foot of the resistor R9; the second foot of the resistor R9 is connected to the first foot of the optocoupler U3; the second foot of the optocoupler U3 is connected to the input terminal HP of the acquisition module 100, and the input terminal HP is connected to the negative terminal BKP of the first battery pack to provide the detection power supply for the contactor RYL3; the third foot of the optocoupler U3 is connected to the second foot of the resistor R25; the fourth foot of the optocoupler U3 is connected to the ground terminal of the acquisition module 100; the first foot of the resistor R25 is connected to the output terminal VP3 of the acquisition module 100, and the on-off detection signal of the contactor RLY3 is output to the MCU chip 300. ;

[0066] It should be noted that the optocouplers U1, U3 or U5 use low-voltage optocouplers, and there is no need to use high-voltage optocouplers, which can greatly reduce hardware costs.

[0067] In the present invention, in specific implementation, the detection working principle of the detection circuit is as follows:

[0068] 1. Contactor disconnection detection

[0069] When the contactor RLY1, RLY3 or RLY5 is disconnected by the BMS software control, the BMS software controls the output terminal DK1, DK3 or DK5 of the MCU chip 300 to output the drive module control signal, so that the output terminal D1, D3 or D5 of the drive module 200 outputs the drive signal, so that the detection switch K1, K3 or K5 of the acquisition module 100 is closed; because the contactor RLY1, RLY3 or RLY5 is disconnected, no detection power supply (first battery pack 10) is connected to the acquisition module 100, the switch Q1, Q3 or Q5 is turned off, the input terminal 1, 2 of the optocoupler U1, U2 or U3 has no power supply connected, and its output terminal 3, 4 is turned off, then the output terminal VP1, VP3 or VP5 of the acquisition module 100 is a high level 5v, which is equal to the power supply voltage output by the 5v power supply module 400; at this time, the BMS software stored in the MCU chip 300 determines that the contactor RLY1, RLY3 or RLY5 is in the disconnected state. If the output terminal VP1, VP3 or VP5 of the acquisition module 100 is not a high level 5v, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is not disconnected (ie, closed), a fault occurs and the fault is recorded.

[0070] After the BMS software completes the above-mentioned contactor disconnection state judgment, the BMS software controls the output terminal DK1, DK3 or DK5 of the MCU chip 300 to output the drive module control signal, so that the output terminal D1, D3 or D5 of the drive module 200 outputs the drive signal, and the detection switch K1, K3 or K5 of the acquisition module 100 is disconnected. At this time, the output terminal VP1, VP3 or VP5 of the acquisition module 100 is at a high level, and the BMS software determines that the acquisition module 100 has no fault. Then the BMS software continues to control the MCU chip 300 to output the drive module control signal, so that the output terminal D1, D3 or D5 of the drive module 200 outputs the drive signal, and the detection switch K1, K3 or K5 of the acquisition module 100 is closed and keeps it in a normally closed state.

[0071] After the detection switch K1, K3 or K5 is controlled to be disconnected, the output terminal DP1, DP3 or DP5 of the acquisition module 100 is not at a high level, and the BMS software determines that the acquisition module 100 fails, and sends a contactor fault alarm signal to the vehicle, and controls the detection switch K1, K3 or K5 to be disconnected.

[0072] It should be noted that the 5V power module 400 always maintains a 5V DC power output within the normal voltage range of the external 12V / 24V power supply.

[0073] It should be noted that the drive module closing control signal output by the output terminal DK1, DK3 or DK5 of the MCU chip 300 can be output after the contactor RLY1, RLY3 or RLY5 is controlled to be opened or closed, so that the detection switch K1, K3 or K5 remains in a normally closed state; it can also keep the detection switch K1, K3 or K5 in a closed state for a certain period of time, and then output the drive module disconnection control signal to disconnect the detection switch K1, K3 or K5; it can also maintain the closed control output after the BMS low voltage is powered on, so that the detection switch K1, K3 or K5 remains in a normally closed state.

[0074] It should be noted that when the BMS is powered off at low voltage, the output terminals DK1, DK3 and DK5 of the MCU chip 300 output the drive module disconnect control signal, so that the drive module 200 has no drive module output, and the detection switches K1, K3 and K5 remain in the disconnected state, thereby avoiding the consumption of power of the first battery group 10 due to contact adhesion failure of the contactors RLY1, RLY3 or RLY5.

[0075] 2. Contactor Closure Detection

[0076] When the contactor RLY1, RLY3 or RLY5 is controlled to be closed by the BMS software, the BMS software controls the output terminal DK1, DK3 or DK5 of the MCU chip 300 to output a drive module control signal, so that the output terminal D1, D3 or D5 of the drive module 200 outputs a drive signal, so that the detection switch K1, K3 or K5 of the acquisition module 100 is closed; because the contactor RLY1, RLY3 or RLY5 is closed, the detection power supply (the first battery pack 10) is connected to the acquisition module 100, the switch Q1, Q3 or Q5 is turned on, and the detection power supply (the first battery pack 10) is connected to the acquisition module 100, and the detection power supply (the first battery pack 10) is connected to the acquisition module 100. After the resistor R9 limits the current, the detection power supply is connected to the input terminals 1 and 2 of the optical coupler U1, U2 or U3 respectively, so that the output terminals 3 and 4 are turned on. Then, after the input power supply 5v of the acquisition module 100 is divided by the resistors R20 and R21, divided by the resistors R22 and R23, or divided by the resistors R24 and R2, the output terminals VP1, VP3 or VP5 of the acquisition module 100 are low level, and the voltage value is equal to half of the difference between the power supply 5v and the conduction voltage drop of the output terminals of the optical coupler U1, U3 or U5; at this time, the BMS software stored in the MCU chip 300 determines that the contactor RLY1, RLY3 or RLY5 is in a closed state. If the output terminals VP1, VP3 or VP5 of the acquisition module 100 are not low level, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is not closed (i.e., disconnected), a fault occurs and records the fault.

[0077] After the BMS software completes the above-mentioned contactor closing state judgment, the BMS software controls the output terminal DK1, DK3 or DK5 of the MCU chip 300 to output the drive module control signal, so that the output terminal D1, D3 or D5 of the drive module 200 outputs the drive signal, and the detection switch K1, K3 or K5 of the acquisition module 100 is disconnected. At this time, the output terminal VP1, VP3 or VP5 of the acquisition module 100 is at a high level, and the BMS software determines that the acquisition module 100 has no fault, and then the BMS software continues to control the MCU chip 300 to output the drive module control signal, so that the output terminal D1, D3 or D5 of the drive module 200 outputs the drive signal, and the detection switch K1, K3 or K5 of the acquisition module 100 is closed and keeps it in a normally closed state.

[0078] If after the detection switch K1, K3 or K5 is controlled to be disconnected, at which time the output terminal VP1, VP3 or VP5 of the acquisition module 100 is not at a high level, the BMS software determines that the acquisition module 100 has a fault, and sends a contactor fault alarm signal to the vehicle, and at the same time controls the detection switch K1, K3 or K5 to be disconnected.

[0079] It should be noted that according to the detection method, combined with the actual high-voltage application solution of the battery system, the initial state (closed or open) of the detection switches K1, K3, and K5 after the BMS is powered on at low voltage can be adjusted, and the control logic of the detection switches K1, K3, and K5 needs to be adjusted accordingly.

[0080] It should be noted that, under the premise of ensuring that the optocoupler U1, U3 or U5 is normally turned on, the resistance values ​​of the current limiting resistors R5, R7, R1, R8, R3 and R9 are as large as possible to reduce the power consumption of the first battery pack 10, for example, the current can be limited to about 10mA.

[0081] It should be noted that the voltage value of the low-level signal at the output terminal VP1, VP3 or VP5 of the acquisition module 100 can be changed by adjusting the resistance of the voltage divider resistor according to actual applications.

[0082] It should be noted that the detection circuit provided by the present invention can be expanded in specific implementation according to the number of high-side circuit contactors used in the power battery system.

[0083] The detection circuit for detecting the on / off of the contactor of the battery system provided by the present invention has a simple circuit structure, and the components used are all of universal models, which can be implemented by domestic devices; low-voltage grade optical couplers are used to replace high-voltage optical couplers and multiple voltage-dividing resistors, thereby reducing hardware costs; and the detection circuit of each contactor is independent and non-coupled.

[0084] In a third aspect of the embodiments of the present invention, a battery management system is provided, including the detection circuit for detecting the on-off of the battery system contactor, or using the detection method for detecting the on-off of the battery system contactor. For the technical content of the detection circuit for detecting the on-off of the battery system contactor and the detection method thereof, please refer to the description of the detection circuit for detecting the on-off of the battery system contactor and the detection principle and method of the above-mentioned embodiments.

[0085] A fourth aspect of an embodiment of the present invention provides a vehicle, comprising the battery management system.

[0086] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description, and it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention.

[0087] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. The detection circuit of the battery system contactor on and off is characterized by: It includes an acquisition module, a drive module, an MCU chip, and a 5V power supply module that provides working voltage for the acquisition module and the MCU chip; the positive terminal BatP of the detection power supply is connected to the first pin of the contactors RLY1, RLY5 and RLY3 respectively, and the input terminals LY5, LY1, and LY3 of the acquisition module are connected to the second pins of the contactors RLY5, RLY1 and RLY3 accordingly; the second pin of the contactor RLY1 is connected in series with a pre-charging resistor R p Then it is connected in parallel with the second foot of the contactor RLY5, and then connected to the main circuit positive port MainP of the power battery system; the second foot of the contactor RLY3 is connected to the positive port DCChgP of the DC charging circuit of the power battery system; the negative terminal BKP of the detection power supply is connected to the input terminal HP of the acquisition module, the output terminals D3, D1, and D5 of the drive module are connected to the corresponding input terminals IN3, IN1, and IN5 of the acquisition module, and the output terminals VP5, VP1, and VP3 of the acquisition module are connected to the corresponding input terminals of the MCU chip; the negative terminal BatN of the power battery pack is connected to the first foot of the contactors RLY2 and RLY4, and the second foot of the contactors RLY2 and RLY4 are respectively connected to the main circuit negative port MainN and the DC charging circuit negative port DCChgN of the power battery system; the output terminals DK5, DK3, and DK1 of the MCU chip are connected to the corresponding input terminals of the drive module.

2. The detection circuit for the on / off of the contactor of the battery system according to claim 1 is characterized in that: The acquisition module includes detection switches K1, K3, K5, switches Q1, Q2, Q3, and optical couplers U1, U2, U3; the first pins of the detection switches K5, K1, K3 are connected to the negative terminal BKP of the first battery pack, the second pins of the detection switches K5, K1, K3 are correspondingly connected to the B poles of the switch tubes Q1, Q2, Q3 through resistors R6, R2, R4, the E poles of the switches Q1, Q2, Q3 are respectively connected to the input terminals LY5, LY1, LY3 of the acquisition module, the C poles of the switches Q1, Q2, Q3 are respectively connected to the first pins of the optical couplers U1, U2, U3, the second pins of the optical couplers U1, U2, U3 are connected to the negative terminal BKP of the first battery pack, the fourth pins of the optical couplers U1, U2, U3 are connected, and the third pins of the optical couplers U1, U2, U3 are connected to the output terminals VP5, VP1, VP3 of the acquisition module; the acquisition module The power input terminal VDD is connected to the output terminals VP5, VP1, and VP3 of the collection module; the E poles and B poles of switches Q1, Q2, and Q3 are connected respectively through resistors R11, R22, and R13; the E poles of switches Q1, Q2, and Q3 are connected to one end of resistors R5, R1, and R3 respectively, and the other ends of resistors R5, R1, and R3 are connected as the input terminals LY5, LY1, and LY3 of the collection module; the C poles of switches Q1, Q2, and Q3 are connected to the first pins of optical couplers U1, U2, and U3 respectively through resistors R7, R8, and R9; the power input terminal VDD of the collection module is connected to the output terminals VP5, VP1, and VP3 of the collection module respectively through resistors R20, R22, and R24; the third pins of optical couplers U1, U2, and U3 are connected to the output terminals VP5, VP1, and VP3 of the collection module respectively through resistors R21, R23, and R25.

3. The detection circuit for the on / off of the contactor of the battery system according to claim 1, characterized in that: The detection switches K1, K3 and K5 are relays, and the positive and negative poles of the drive module are connected to the positive and negative poles of the coils of the detection switches K1, K3 and K5 respectively.

4. The detection circuit for the on-off of the contactor of the battery system according to claim 1, characterized in that: The detection power source is a first battery group of a power battery group, and the first battery group is a plurality of single cells connected in series in a positive terminal group of a power battery.

5. The detection circuit for the on-off of the contactor of the battery system according to claim 1, characterized in that: The power input terminal VDD of the acquisition module and the power input terminal Vdd of the MCU chip are connected to the power output terminal of the 5V power module, which is used to connect the voltage and current of the 5V DC power supply.

6. The detection circuit for the on-off of the contactor of the battery system according to claim 1, characterized in that: The 5V power module input end and the DP end of the driving module are connected to an external 12V / 24V DC power supply of the power management system BMS.

7. The detection circuit for the on-off of the contactor of the battery system according to claim 6, characterized in that: The 12v / 24v DC power source is a 12v / 24v storage battery, a power battery or a DC power supply device of a car.

8. A method for detecting the on / off state of a battery system contactor, characterized in that: The detection circuit for the on / off of the battery system contactor according to any one of claims 1 to 7 is implemented and controlled by the battery management system BMS software, including: After the BMS software controls the contactor RLY1, RLY3 or RLY5 to close, the BMS software controls the output terminal DK1, DK3 or DK5 of the MCU chip to output a detection control signal, so that the output terminal D1, D3 or D5 of the drive module outputs a 12v / 24v DC power supply, and provides a drive signal for the detection switch K1, K3 or K5 of the acquisition module to close the detection switch K1, K3 or K5. Then, the voltage between the input terminal LY1, LY3 or LY5 of the acquisition module and the negative terminal BKP of the first battery pack is equal to the voltage of the first battery pack, that is, there is a detection power supply connected. Input, at this time, the signal of the output terminal VP1, VP3 or VP5 of the acquisition module is low level, and the BMS software determines that the contactor RLY1, RLY3 or RLY5 is closed; at this time, if the signal of the output terminal VP1, VP3 or VP5 of the acquisition module is low level, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is closed, and no fault occurs; if the signal of the output terminal VP1, VP3 or VP5 of the acquisition module is high level, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is not closed, a fault occurs, and the fault is recorded; After the BMS software completes the determination of the closed state of the contactor, after a set delay time, the output terminal DK1, DK3 or DK5 of the MCU chip is controlled to output the detection switch K1, K3 or K5 to disconnect the control signal. At this time, if the output terminal VP1, VP3 or VP5 of the acquisition module is at a high level, the BMS software determines that the acquisition module has no fault. If the output terminal VP1, VP3 or VP5 of the acquisition module is not at a high level, the BMS software determines that the acquisition module has a fault. When no fault occurs in the acquisition module, the BMS software continues to control the output terminal DK1, DK3 or DK5 of the MCU chip to output the detection switch K1, K3 or K5 closing control signal to close the detection switch K1, K3 or K5. At this time, if the output terminal VP1, VP3 or VP5 of the acquisition module is at a low level, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is closed and no fault occurs, and then keeps the detection switch K1, K3 or K5 in a normally closed state; if the output terminal VP1, VP3 or VP5 of the acquisition module is at a high level, the BMS software determines that the contactor is not closed and a fault occurs, sends a contactor fault alarm signal to the vehicle, and then controls the detection switch K1, K3 or K5 to be disconnected; When the acquisition module fails, the BMS sends a contactor fault alarm signal to the vehicle, and at the same time, the BMS software controls the output terminal DK5, DK3 or DK1 of the MCU chip to output a detection switch K1, K3 or K5 disconnection control signal to disconnect the detection switch K1, K3 or K5; After the BMS software controls the contactor RLY1, RLY3 or RLY5 to be disconnected, a detection power supply is connected between the input terminal LY1, LY3, LY5 of the acquisition module and the negative terminal BKP of the first battery pack. At this time, if the output signal of the output terminal VP1, VP3 or VP5 of the acquisition module is high, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is disconnected and no fault occurs; if the output signal of the output terminal VP1, VP3 or VP5 of the acquisition module is low, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is not disconnected, a fault occurs, and the fault is recorded; After the BMS software completes the judgment on the disconnection state of the contactor RLY1, RLY3 or RLY5, it controls the output terminal DK1, DK3 or DK5 of the MCU chip to output the detection switch K1, K3 and K5 to disconnect the control signal after the set delay time. At this time, if the output terminal VP1, VP3 or VP5 of the acquisition module is at a high level, the BMS software determines that the acquisition module has no fault. If the output terminal VP1, VP3 or VP5 is not at a high level, the BMS software determines that the acquisition module has a fault. When no fault occurs in the acquisition module, the BMS software continues to control the output terminal DK5, DK3 or DK1 of the MCU chip to output a closing control signal of the detection switch K1, K3 or K5 to close the detection switch K1, K3 or K5. At this time, if the output terminal VP5, VP3 or VP1 of the acquisition module is at a high level, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is disconnected and no fault occurs, and then controls the MCU chip to output a closing control signal to keep the detection switch K1, K3 or K5 in a normally closed state; if the output terminal VP1, VP3 or VP5 of the acquisition module is at a low level, the BMS software determines that the contactor RLY1, RLY3 or RLY5 is not disconnected and a fault occurs, sends a contactor fault alarm signal to the vehicle, and then controls the detection switch K1, K3 or K5 to be disconnected; When the acquisition module fails, the BMS sends a contactor fault alarm signal to the vehicle. At the same time, the BMS software controls the output terminal DK1, DK3 or DK5 of the MCU chip to output a detection switch K1, K3 or K5 disconnection control signal to disconnect the detection switch K1, K3 or K5.

9. A battery management system, characterized in that: The invention comprises a detection circuit for detecting the on-off of a battery system contactor as described in any one of claims 1 to 7, or adopts the detection method as described in claim 8 to detect the on-off of a battery system contactor.

10. A vehicle, characterized in that Including the battery management system as claimed in claim 9.

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