CN214539920U - Relay fault detection circuit, battery management system and vehicle - Google Patents
Relay fault detection circuit, battery management system and vehicle Download PDFInfo
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- CN214539920U CN214539920U CN202120571351.3U CN202120571351U CN214539920U CN 214539920 U CN214539920 U CN 214539920U CN 202120571351 U CN202120571351 U CN 202120571351U CN 214539920 U CN214539920 U CN 214539920U
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Abstract
The present disclosure relates to a relay fault detection circuit, a battery management system, and a vehicle. This circuit includes power battery, first relay, first resistance, voltage acquisition branch road and relay detection branch road, wherein: the first end of the first relay is connected with the first end of the power battery, and the second end of the first relay is connected with a high-voltage load of the vehicle; one end of the first resistor is connected with the second end of the power battery, and the other end of the first resistor is connected with the second end of the first relay; two acquisition input ends of the voltage acquisition branch are respectively connected with two ends of the first relay, and an acquisition output end of the voltage acquisition branch is connected with the relay detection branch; the relay detection branch circuit is used for acquiring a first electric signal of the acquisition output end and a high-voltage electric state signal of the vehicle, and determining whether the first relay has a fault or not by comparing the first electric signal with the high-voltage electric state signal. Therefore, whether the relay has a fault or not can be detected in time, and the safety is improved.
Description
Technical Field
The present disclosure relates to the field of vehicles, and in particular, to a relay fault detection circuit, a battery management system, and a vehicle.
Background
With the popularization and application of new energy vehicles, the safety requirements of users on the new energy vehicles are higher and higher. No matter plug-in hybrid electric vehicle or pure electric vehicle, power battery is its main power output source, provides high-tension electricity for the high-voltage load of vehicle, and power battery's power output is by the relay control of vehicle, but after the vehicle uses a period, the relay probably takes place the adhesion problem, can lead the high-tension electricity of actuating force battery to reveal, influences whole car and personnel safety.
SUMMERY OF THE UTILITY MODEL
In order to solve the above problem, the present disclosure provides a relay failure detection circuit, a battery management system, and a vehicle.
In a first aspect, the present disclosure provides a relay fault detection circuit, which is applied to a vehicle, wherein the circuit includes a power battery, a first relay, a first resistor, a voltage acquisition branch and a relay detection branch, wherein:
the first end of the first relay is connected with the first end of the power battery, and the second end of the first relay is connected with a high-voltage load of the vehicle;
one end of the first resistor is connected with the second end of the power battery, and the other end of the first resistor is connected with the second end of the first relay;
two acquisition input ends of the voltage acquisition branch are respectively connected with the first end and the second end of the first relay, and an acquisition output end of the voltage acquisition branch is connected with the relay detection branch;
the relay detection branch is used for acquiring a first electric signal of the acquisition output end and a high-voltage electric state signal of the vehicle, and determining whether the first relay has a fault or not by comparing the first electric signal with the high-voltage electric state signal.
Optionally, the relay detection branch includes a controller and a high-low voltage isolation assembly, wherein:
the first input end of the high-low voltage isolation assembly is connected with the acquisition output end of the voltage acquisition branch circuit, the second input end of the high-low voltage isolation assembly is grounded, the first output end of the high-low voltage isolation assembly is connected with the controller, the second output end of the high-low voltage isolation assembly is grounded, the high-low voltage isolation assembly is used for acquiring a first electric signal of the acquisition output end, and the first output end and the second output end of the high-low voltage isolation assembly are controlled to be in a connection state under the condition that the voltage value of the first electric signal is greater than or equal to a first preset voltage threshold value; under the condition that the voltage value of the first electric signal is smaller than the first preset voltage threshold, controlling a first output end and a second output end of the high-low voltage isolation assembly to be in a disconnected state;
the controller is used for determining that the actual switching state of the first relay is a closed state under the condition that the first output end and the second output end of the high-low voltage isolation assembly are in an open state; under the condition that a first output end and a second output end of the high-low voltage isolation assembly are in a connected state, determining that the actual switch state of the first relay is in a disconnected state;
the controller is further configured to obtain a high voltage power-on state signal of the vehicle, determine an expected switching state of the first relay according to the high voltage power-on signal, and determine that the first relay has a fault when the actual switching state is inconsistent with the expected switching state.
Optionally, the high-low voltage isolation assembly includes any one of a photocoupler, an isolation transformer and an isolation capacitor.
Optionally, the voltage acquisition branch includes a first acquisition module, a second acquisition module and an operational amplifier: wherein:
two input ends of the operational amplifier are respectively connected with the output end of the first acquisition module and the output end of the second acquisition module;
two ends of the first relay are respectively connected with the acquisition input end of the first acquisition module and the acquisition input end of the second acquisition module;
and the acquisition output end of the operational amplifier is connected with the relay detection branch.
Optionally, the first acquisition module and the second acquisition module are both analog-to-digital converters.
Optionally, the voltage collecting branch comprises a triode or a metal-oxide semiconductor field effect transistor.
Optionally, the circuit further includes a first switch, and two ends of the first switch are respectively connected to the second end of the power battery and the first resistor.
Optionally, the first relay is a main negative relay of the vehicle, the circuit further includes a main positive relay, a pre-charging branch and a high-voltage load, wherein:
the first end of the power battery is a negative electrode, the second end of the power battery is a positive electrode, and the positive electrode of the power battery is connected with the main positive relay and the pre-charging branch circuit;
the pre-charging branch comprises a pre-charging relay and a pre-charging resistor.
In a second aspect, the present disclosure provides a battery management system comprising the relay fault detection circuit of the first aspect.
In a third aspect, the present disclosure provides a vehicle including the relay failure detection circuit of the first aspect.
By adopting the technical scheme, the relay fault detection circuit comprises the power battery, the first relay, the first resistor, the voltage acquisition branch circuit and the relay detection branch circuit, the first electric signal of the acquisition output end of the voltage acquisition branch circuit and the high-voltage electric state signal of the vehicle are acquired through the relay detection branch circuit, the first electric signal and the high-voltage electric state signal are compared, and whether the first relay has a fault or not is determined. Therefore, whether the vehicle is electrified at high voltage or not can be detected whether the relay has faults or not in time, and the safety of the vehicle and personnel can be improved.
Additional features and advantages of the disclosure will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:
fig. 1 is a schematic structural diagram of a high-voltage control circuit of a vehicle according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of a relay fault detection circuit provided in an embodiment of the present disclosure;
fig. 3 is a schematic structural diagram of another relay fault detection circuit provided in the embodiment of the present disclosure;
fig. 4 is a schematic structural diagram of another relay fault detection circuit provided in the embodiment of the present disclosure;
fig. 5 is a block diagram of a battery management system provided by an embodiment of the present disclosure;
fig. 6 is a block diagram of a vehicle provided by an embodiment of the present disclosure.
Detailed Description
The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.
It is noted that, in the present disclosure, the terms "first," "second," and the like are used for descriptive purposes only and not for purposes of indicating or implying relative importance, nor for purposes of indicating or implying order.
First, an application scenario of the present disclosure will be explained. The relay detection method and the relay detection device can be applied to relay detection scenes of new energy vehicles. Fig. 1 is a schematic structural diagram of a high-voltage control circuit of a vehicle according to an embodiment of the present disclosure, and as shown in fig. 1, the high-voltage control circuit includes a power battery 101, a high-voltage load 102, a main negative relay K1, a main positive relay K2, and a pre-charging branch 103, where the pre-charging branch 103 includes a pre-charging relay K3 and a pre-charging resistor R0. In the related art, it is necessary to determine whether the relay is normally operated by comparing the voltage across the power battery and the voltage across the high-voltage load in the case where the vehicle is powered on at a high voltage. For example, in the case of vehicle high voltage power-up, the main negative relay K1 and the main positive relay K2 are both closed, and the pre-charge relay K3 is opened, so that the voltage across the high voltage load is equal to the voltage across the power battery. At this time, under the condition that the main positive relay K2 is kept closed, after the main negative relay K1 is controlled to be switched off, if the voltage at two ends of the high-voltage load is gradually reduced to 0, the main negative relay K1 is determined to be normal; on the contrary, after the main negative relay K1 is controlled to be switched off, if the voltages at the two ends of the high-voltage load are still equal to the voltages at the two ends of the power battery, it can be determined that the main negative relay K1 has the adhesion fault, and the main negative relay needs to be replaced. Likewise, with main negative relay K2 held closed, it can be determined in the same way whether main positive relay K2 has a stuck fault. When the method in the related technology is used for relay fault detection, detection can be completed only by switching the corresponding relay for multiple times under the condition that the vehicle is electrified at high voltage, and the detection can be performed only in an off-line state of the vehicle and cannot be performed in time.
In order to solve the above problem, the present disclosure provides a relay fault detection circuit, a battery management system and a vehicle, where the relay fault detection circuit includes a power battery, a first relay, a first resistor, a voltage acquisition branch and a relay detection branch, and acquires a first electrical signal at an acquisition output end of the voltage acquisition branch and a high-voltage state signal of the vehicle through the relay detection branch, and compares the first electrical signal with the high-voltage state signal to determine whether the first relay has a fault. Therefore, whether the vehicle is electrified at high voltage or not can be detected whether the relay has faults or not in time, and the safety of the vehicle and personnel can be improved.
The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings.
Fig. 2 is a schematic structural diagram of a relay fault detection circuit provided in an embodiment of the present disclosure, and as shown in fig. 2, the circuit may be applied to a vehicle, and the circuit includes:
the circuit comprises a power battery 101, a first relay Kx, a first resistor R1, a voltage acquisition branch 201 and a relay detection branch 202, wherein:
the first terminal U1 of the first relay Kx is connected to the first terminal of the power battery 101, and the second terminal U2 of the first relay Kx is connected to the high voltage load 102 of the vehicle.
One end of the first resistor R1 is connected to the second end of the power battery 101, and the other end of the first resistor R1 is connected to the second end U2 of the first relay Kx.
Two collecting input ends of the voltage collecting branch 201 are respectively connected with a first end U1 and a second end U2 of the first relay; the collection output end of the voltage collection branch is connected with the relay detection branch.
The relay detection branch 202 is configured to obtain a first electrical signal at the acquisition output end and a high voltage state signal of the vehicle, and determine whether the first relay has a fault by comparing the first electrical signal with the high voltage state signal.
The actual on-off state of the first relay can be obtained through the first electric signal of the acquisition output end of the voltage acquisition branch circuit, the expected on-off state of the first relay can be obtained through the high-voltage electric state signal, and therefore whether the actual on-off state of the first relay is consistent with the expected on-off state can be determined by comparing the first electric signal with the high-voltage electric state signal. In the event that the actual switch state is inconsistent with the expected switch state, it may be determined that the first relay has a fault; on the contrary, under the condition that the actual switch state is consistent with the expected switch state, the first relay can be determined to be in normal operation without fault.
It should be noted that the corresponding relationship between the first electrical signal at the acquisition output end of the voltage acquisition branch and the actual on-off state of the first relay is described as follows:
under the condition that the first relay is closed, the voltage between the first end U1 and the second end U2 of the first relay Kx is 0, and the voltage output by the voltage acquisition branch is also 0; in the case that the first relay is opened, the voltage between the first terminal U1 and the second terminal U2 of the first relay Kx is equal to the voltage of the power battery, which is a large value, for example, the voltage of the power battery may be 300V, and in the case that the first relay is opened, the voltage between the first terminal U1 and the second terminal U2 of the first relay Kx is also 300V, and the voltage of the first electrical signal may be 300V; it can also be reduced to a lower voltage, for example to 12V, by a voltage divider circuit. In this way, the actual switching state of the first relay can be obtained from the voltage value of the first electrical signal.
It should be further noted that the high voltage state signal is used to characterize a high voltage state of the vehicle, and the high voltage state includes any one of a high voltage down state, a high voltage pre-charge state and a high voltage up state, and the three states can be distinguished by different high voltage state signals, and the expected switch state of the first relay is fixed in different high voltage states. In this way, the desired switching state of the first relay can be derived from the high voltage status signal. The correspondence of the high voltage status signal to the expected switching status of the first relay is explained as follows:
in the case of a high-voltage low-voltage state of the vehicle, the expected switching states of the main negative relay K1, the main positive relay K2, and the pre-charge relay K3 are all off states, and the power battery does not supply power to the high-voltage load.
Under the condition that the high-voltage state of the vehicle is high-voltage pre-charging, the expected switch states of the main negative relay K1 and the pre-charging relay K3 are both closed states, the expected switch state of the main positive relay K2 is an open state, and the voltage at two ends of the high-voltage load is gradually increased from 0 due to the action of the pre-charging resistor R0;
under the condition of high-voltage electrification in a high-voltage state of a vehicle, the expected switch states of the main negative relay K1 and the main positive relay K2 are both closed states, the expected switch state of the pre-charging relay K3 is an open state, and the power battery supplies power to a high-voltage load normally.
The first relay may be any one of the main negative relay K1, the main positive relay K2, or the precharge relay K3 described above.
At the moment, the relay detection branch CAN acquire a high-voltage state signal as a first preset signal through a CAN bus of the vehicle, the first preset signal represents the high-voltage state of the vehicle, the high-voltage state of the vehicle is determined through the first preset signal, and then the expected switch state of the first relay CAN be determined.
Thus, based on the actual and expected switch states, it can be determined whether the first relay has a fault.
By way of example, taking the first relay as the main negative relay K1 as an example, the manner for determining whether the first relay has a fault is described as follows by using the circuit:
under the condition that the high-voltage state of the vehicle is the high-voltage low-voltage state, the relay detection branch circuit CAN acquire a high-voltage state signal as a first preset signal through a CAN (controller area network) bus of the vehicle, the first preset signal represents that the high-voltage state of the vehicle is the high-voltage low-voltage state, and at the moment, the expected switch state of the first relay (the main negative relay K1) is the off state. The relay detection branch can also obtain a first electric signal of the acquisition output end, if the voltage value of the first electric signal is 0 or less than a second preset voltage threshold value, the actual switching state of the first relay is a closed state, and at the moment, the first relay can be determined to have a fault according to the first electric signal and the high-voltage electric state signal; on the contrary, if the voltage value of the first electrical signal is greater than or equal to the second preset voltage threshold, the actual switch state of the first relay is the off state, so that the first relay is determined to be free from faults according to the first electrical signal and the high-voltage electrical state signal.
Under the condition that the high-voltage state of the vehicle is a high-voltage power-on state, the relay detection branch circuit CAN acquire a high-voltage state signal as a second preset signal through a CAN (controller area network) bus of the vehicle, the second preset signal represents that the high-voltage state of the vehicle is the high-voltage power-on state, and at the moment, the expected switch state of the first relay (the main negative relay K1) is a closed state. Likewise, it can be determined whether the first relay has a fault based on the first electrical signal and the high voltage status signal.
Under the condition that the high-voltage electric state of the vehicle is divided into a high-voltage pre-charging state, the relay detection branch circuit CAN acquire a high-voltage electric state signal as a third preset signal through a CAN (controller area network) bus of the vehicle, the third preset signal represents that the high-voltage electric state of the vehicle is divided into the high-voltage pre-charging state, and at the moment, the expected switch state of the first relay (the main negative relay K1) is a closed state. It is also possible to determine whether the first relay has a fault based on the first electrical signal and the high voltage status signal.
In summary, in a case that the first relay is a main negative relay, if the first electrical signal and the high voltage status signal satisfy a first preset condition, it may be determined that the first relay has a fault, where the first preset condition includes any one of the following conditions:
the high-voltage electric state signal is the first preset signal, and the voltage value of the first electric signal is smaller than a second preset voltage threshold value;
the high-voltage electric state signal is the second preset signal, and the voltage value of the first electric signal is greater than or equal to a second preset voltage threshold value;
the high-voltage state signal is the third preset signal, and the voltage value of the first electric signal is greater than or equal to a second preset voltage threshold value.
Similarly, in the case that the first relay is a main positive relay, if the first electrical signal and the high voltage status signal satisfy a second preset condition, it may be determined that the first relay has a fault, where the second preset condition includes any one of the following conditions:
the high-voltage electric state signal is the first preset signal, and the voltage value of the first electric signal is smaller than a second preset voltage threshold value;
the high-voltage electric state signal is the second preset signal, and the voltage value of the first electric signal is greater than or equal to a second preset voltage threshold value;
the high-voltage state signal is the third preset signal, and the voltage value of the first electric signal is smaller than a second preset voltage threshold value.
Similarly, in the case that the first relay is a pre-charge relay, if the first electrical signal and the high voltage status signal satisfy a second predetermined condition, the first relay may be determined to have a fault, and the second predetermined condition may include any one of the following conditions:
the high-voltage electric state signal is the first preset signal, and the voltage value of the first electric signal is smaller than a second preset voltage threshold value;
the high-voltage electric state signal is the second preset signal, and the voltage value of the first electric signal is smaller than a second preset voltage threshold value;
the high-voltage state signal is the third preset signal, and the voltage value of the first electric signal is greater than or equal to a second preset voltage threshold value.
The second preset voltage threshold may be set empirically, and may be set to any value between 3V and 300V.
Adopt above-mentioned circuit, including power battery, first relay, first resistance, voltage acquisition branch road and relay detection branch road, detect the branch road through this relay, acquire the first signal of telecommunication of the collection output of this voltage acquisition branch road to and the high-tension electricity status signal of vehicle, and compare this first signal of telecommunication and this high-tension electricity status signal, confirm whether this first relay has the trouble. Therefore, whether the vehicle is electrified at high voltage or not can be detected whether the relay has faults or not in time, and the safety of the vehicle and personnel can be improved.
Fig. 3 is a schematic structural diagram of another relay fault detection circuit provided in the present disclosure, and as shown in fig. 3, the relay detection branch 202 includes a controller 2021 and a high-low voltage isolation assembly 2022, where:
the first input end of the high-low voltage isolation assembly 2022 is connected to the IN1, the collecting output end OUT3 of the voltage collecting branch 201, the second input end IN2 of the high-low voltage isolation assembly 2022 is grounded, the first output end OUT1 of the high-low voltage isolation assembly 2022 is connected to the controller 2021, the second output end OUT2 of the high-low voltage isolation assembly 2022 is grounded, the high-low voltage isolation assembly 2022 is used for obtaining a first electrical signal of the collecting output end OUT3, and the first output end OUT1 and the second output end OUT2 of the high-low voltage isolation assembly 2022 are controlled to be IN a connection state when the voltage value of the first electrical signal is greater than or equal to a first preset voltage threshold; under the condition that the voltage value of the first electrical signal is smaller than the first preset voltage threshold, controlling the first output end OUT1 and the second output end OUT2 of the high-low voltage isolation assembly 2022 to be in an off state;
the controller 2021 is configured to determine that the actual switching state of the first relay is a closed state when the first output end OUT1 and the second output end OUT2 of the high-low voltage isolation assembly 2022 are in an open state; determining that the actual switching state of the first relay is an open state under the condition that the first output end OUT1 and the second output end OUT2 of the high-low voltage isolation assembly 2022 are in a connected state;
the controller 2021 is further configured to obtain a high voltage power-on signal of the vehicle, determine an expected switch state of the first relay according to the high voltage power-on signal, and determine that the first relay has a fault if the actual switch state is inconsistent with the expected switch state.
Therefore, under the condition that the vehicle is electrified at high voltage or is not electrified at high voltage, the actual switching state of the first relay can be detected in time and compared with the expected switching state of the first relay to determine whether the first relay has faults or not, and the safety of the vehicle and personnel can be improved.
Further, the high-low voltage isolation assembly can comprise any one of a photoelectric coupler, an isolation transformer and an isolation capacitor, so that high-low voltage isolation is realized, the circuit safety of the controller is ensured, and the reliability of relay fault detection is improved.
Fig. 4 is a schematic structural diagram of another relay fault detection circuit provided in the present disclosure, and as shown in fig. 4, the voltage acquisition branch includes a first acquisition module 2011, a second acquisition module 2012 and an operational amplifier 2013: wherein:
the two input ends of the operational amplifier 2013 are respectively connected with the output end of the first acquisition module 2011 and the output end of the second acquisition module 2012;
two ends of the first relay are respectively connected with the acquisition input end IN1 of the first acquisition module 2011 and the acquisition input end IN2 of the second acquisition module 2012;
the collection output end OUT3 of the operational amplifier 2013 is connected with the relay detection branch.
The first acquisition module and the second acquisition module can be both analog-digital converters. The electrical signals at two ends of the first relay can be converted into digital signals, the converted digital signals are output to an operational amplifier, the operational amplifier operates according to the digital signals to obtain a voltage difference value at two ends of the first relay, and the voltage difference value is output to the relay detection branch from the acquisition output end OUT3 of the operational amplifier. For example, a voltage difference of 0 may indicate that the actual switch state of the first relay is a closed state; the voltage difference is greater than or equal to a first preset voltage threshold, which can indicate that the actual switch state of the first relay is an off state.
Therefore, the acquisition of the voltage difference value at two ends of the first relay is realized through the first acquisition module, the second acquisition module and the operational amplifier, and the actual switching state of the first relay is determined through the voltage difference value.
Optionally, the voltage collecting branch may also adopt a triode or a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET).
Therefore, the cost of the voltage acquisition branch can be reduced, and the relay fault detection with low cost is realized.
Further, as shown in fig. 4, the circuit may further include a first switch K0, and two ends of the first switch K0 are respectively connected to the second end of the power battery and the first resistor R1.
The first switch and the controller CAN be connected with a CAN bus of the vehicle, and the controller CAN control the first switch K0 to be closed and opened. Thus, when the first relay needs to be subjected to fault detection, the control can control the first switch K0 to be closed so as to carry out fault detection; when fault detection is not required, power loss caused by the detection circuit is avoided.
In any of the above embodiments, the first resistor may be a single resistor, or may be a plurality of resistors connected in series. The resistance of the first resistor may be set large enough to ensure that the current on the relay fault detection circuit is small enough. The first resistor may have any value greater than 100 kilo-ohms, for example, 500 kilo-ohms, 100 mega-ohms or 900 mega-ohms.
In another embodiment of the present disclosure, as shown in fig. 4, the first relay may be a main negative relay of the vehicle, the circuit further includes a main positive relay K2, a pre-charge branch 103 and a high voltage load 102, wherein:
the first end of the power battery 101 is a negative electrode, the second end is a positive electrode, and the positive electrode of the power battery 101 is connected with the main positive relay K2 and the pre-charging branch 103;
the pre-charge branch 103 includes a pre-charge relay K3 and a pre-charge resistor R0.
It should be noted that, in the above drawings, the first relay is taken as a main negative relay of the vehicle for example, and the first relay in the embodiment of the present disclosure may also be a main positive relay or a pre-charge relay of the vehicle.
Fig. 5 is a block diagram of a battery management system provided in an embodiment of the present disclosure, and as shown in fig. 5, the battery management system includes a relay fault detection circuit provided in any of the embodiments.
Fig. 6 is a block diagram of a vehicle provided in an embodiment of the present disclosure, and as shown in fig. 6, the vehicle includes a relay fault detection circuit provided in any one of the embodiments.
The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.
It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. In order to avoid unnecessary repetition, various possible combinations will not be separately described in this disclosure.
In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.
Claims (10)
1. The utility model provides a relay fault detection circuit which characterized in that is applied to the vehicle, the circuit includes power battery, first relay, first resistance, voltage acquisition branch road and relay detection branch road, wherein:
the first end of the first relay is connected with the first end of the power battery, and the second end of the first relay is connected with a high-voltage load of the vehicle;
one end of the first resistor is connected with the second end of the power battery, and the other end of the first resistor is connected with the second end of the first relay;
two acquisition input ends of the voltage acquisition branch are respectively connected with the first end and the second end of the first relay, and an acquisition output end of the voltage acquisition branch is connected with the relay detection branch;
the relay detection branch is used for acquiring a first electric signal of the acquisition output end and a high-voltage electric state signal of the vehicle, and determining whether the first relay has a fault or not by comparing the first electric signal with the high-voltage electric state signal.
2. The circuit of claim 1, wherein the relay detection branch comprises a controller and a high-low voltage isolation assembly, wherein:
the first input end of the high-low voltage isolation assembly is connected with the acquisition output end of the voltage acquisition branch circuit, the second input end of the high-low voltage isolation assembly is grounded, the first output end of the high-low voltage isolation assembly is connected with the controller, the second output end of the high-low voltage isolation assembly is grounded, the high-low voltage isolation assembly is used for acquiring a first electric signal of the acquisition output end, and the first output end and the second output end of the high-low voltage isolation assembly are controlled to be in a connection state under the condition that the voltage value of the first electric signal is greater than or equal to a first preset voltage threshold value; under the condition that the voltage value of the first electric signal is smaller than the first preset voltage threshold, controlling a first output end and a second output end of the high-low voltage isolation assembly to be in a disconnected state;
the controller is used for determining that the actual switching state of the first relay is a closed state under the condition that the first output end and the second output end of the high-low voltage isolation assembly are in an open state; under the condition that a first output end and a second output end of the high-low voltage isolation assembly are in a connected state, determining that the actual switch state of the first relay is in a disconnected state;
the controller is further configured to obtain a high voltage power-on state signal of the vehicle, determine an expected switching state of the first relay according to the high voltage power-on signal, and determine that the first relay has a fault when the actual switching state is inconsistent with the expected switching state.
3. The circuit of claim 2, wherein the high-low voltage isolation component comprises any one of a photocoupler, an isolation transformer, and an isolation capacitor.
4. The circuit of claim 1, wherein the voltage acquisition branch comprises a first acquisition module, a second acquisition module, and an operational amplifier: wherein:
two input ends of the operational amplifier are respectively connected with the output end of the first acquisition module and the output end of the second acquisition module;
two ends of the first relay are respectively connected with the acquisition input end of the first acquisition module and the acquisition input end of the second acquisition module;
and the acquisition output end of the operational amplifier is connected with the relay detection branch.
5. The circuit of claim 4, wherein the first acquisition module and the second acquisition module are both analog-to-digital converters.
6. The circuit of claim 1, wherein the voltage harvesting branch comprises a triode or a metal-oxide semiconductor field effect transistor.
7. The circuit of claim 1, further comprising a first switch, wherein two ends of the first switch are respectively connected to the second end of the power battery and the first resistor.
8. The circuit of any one of claims 1 to 7, wherein the first relay is a main negative relay of the vehicle, the circuit further comprising a main positive relay, a pre-charge branch, and a high voltage load, wherein:
the first end of the power battery is a negative electrode, the second end of the power battery is a positive electrode, and the positive electrode of the power battery is connected with the main positive relay and the pre-charging branch circuit;
the pre-charging branch comprises a pre-charging relay and a pre-charging resistor.
9. A battery management system comprising the relay fault detection circuit of any one of claims 1 to 8.
10. A vehicle characterized by comprising the relay failure detection circuit according to any one of claims 1 to 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120571351.3U CN214539920U (en) | 2021-03-19 | 2021-03-19 | Relay fault detection circuit, battery management system and vehicle |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120571351.3U CN214539920U (en) | 2021-03-19 | 2021-03-19 | Relay fault detection circuit, battery management system and vehicle |
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| CN214539920U true CN214539920U (en) | 2021-10-29 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114137405A (en) * | 2021-11-25 | 2022-03-04 | 沃太能源股份有限公司 | Fault detection method for relay device and device thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114137405A (en) * | 2021-11-25 | 2022-03-04 | 沃太能源股份有限公司 | Fault detection method for relay device and device thereof |
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