Evaluation method, electronic device, evaluation circuit, load circuit and vehicle

Abstract

The invention discloses a relay state evaluation method, an electronic device, a relay state evaluation circuit, a load circuit and a vehicle. The state evaluation method comprises the following steps: in response to a power-on signal or a power-off signal, communicating a corresponding relay in a load circuit with a detection circuit, so that a to-be-detected contact pair of the relay and a loop resistor of the detection circuit are connected in parallel between a detection power supply of the detection circuit, the resistance value of the loop resistor is matched with the resistance value of the contact resistor of the contact pair to be detected when the relay is adhered; and determining the working state of the relay according to the proportion value of the second current value flowing through the loop resistor and the first current value output by the detection power supply. The state evaluation method of the relay can reflect the tiny change condition of the contact resistance of the relay at the milliohm level so as to accurately reflect the working state of the relay.

Description

Technical Field

[0001] The present application relates to the technical field of relays, and more specifically, to a relay state evaluation method, an electronic device, a relay state evaluation circuit, a load circuit, and a vehicle. Background Art

[0002] In the related art, in order to detect whether the contacts of the relay are stuck, it is necessary to detect the contact resistance between the contacts of the relay, and determine whether the contacts of the relay are stuck according to the size of the contact resistance between the contacts of the relay. The contact resistance between the contacts of the relay is detected by using the voltage drop method, that is, the contact resistance between the contacts is calculated by measuring the voltage drop across the contact pair of the resistance relay.

[0003] However, since the contact resistance between the contacts of the relay in the electric vehicle distribution box is small (usually in the range of 0.05 milliohms to 5 milliohms), and even if there is adhesion between the contacts, the change in contact resistance between the contacts is small, it is difficult to accurately detect the change in contact resistance, and it is also difficult to determine whether the contacts of the detection relay are adhered based on the size of the contact resistance. Summary of the invention

[0004] Embodiments of the present application provide a relay state evaluation method, an electronic device, a relay state evaluation circuit, a load circuit, and a vehicle.

[0005] The status assessment method provided in the embodiment of the present application includes: in response to a power-on signal or a power-off signal, connecting the corresponding relay in the load circuit and the detection circuit so that the contact pair to be tested of the relay and the loop resistance of the detection circuit are connected in parallel between the detection power supply of the detection circuit, and the resistance value of the loop resistance matches the resistance value of the contact resistance of the contact pair to be tested when the relay is stuck; determining the working state of the relay according to the ratio of the second current value flowing through the loop resistance to the first current value flowing through the detection power supply.

[0006] In this way, the relay status evaluation method provided in the embodiment of the present application can reflect the slight changes in the contact resistance of the relay at the milliohm level, so as to accurately reflect the working status of the relay.

[0007] In certain embodiments, the load circuit includes a main positive relay and a main negative relay, a positive connection loop and a negative connection loop, the main positive relay is configured as a relay for the positive connection loop, the main negative relay is configured as a relay for the negative connection loop, and the corresponding relays in the load circuit are connected with the detection circuit in response to a power-on signal or a power-off signal, including: in response to the power-on signal, connecting the first contact pair to be tested of the main positive relay with the detection circuit, and disconnecting the second contact pair to be tested of the main negative relay from the detection circuit; or in response to the power-on signal, connecting the second contact pair to be tested with the detection circuit, and disconnecting the first contact pair to be tested with the detection circuit.

[0008] In certain embodiments, when the first contact pair to be tested is connected to the detection circuit, the ratio of the second current value to the first current value is a first ratio value, and when the second contact pair to be tested is connected to the detection circuit, the ratio of the second current value to the first current value is a second ratio value, then determining the working state of the relay based on the ratio of the second current value flowing through the loop resistance to the first current value output by the detection power supply includes: when the first ratio value is greater than or equal to a first ratio threshold value, determining that the contact resistance of the first contact pair to be tested is abnormally increased to determine that the main positive relay has poor contact; or when the second ratio value is greater than or equal to the first ratio threshold value, determining that the contact resistance of the second contact pair to be tested is abnormally increased to determine that the main negative relay has poor contact.

[0009] In certain embodiments, determining the operating state of the relay based on the ratio of the second current value flowing through the loop resistor to the first current value output by the detection power supply also includes: when the first ratio value is 1, determining that the main positive relay has an inoperative coil or is energized and not conducting; or when the second ratio value is 1, determining that the main negative relay has an inoperative coil or is energized and not conducting.

[0010] In certain embodiments, when the first contact pair to be tested is connected to the detection circuit, the ratio of the second current value to the first current value is a first ratio value, and when the second contact pair to be tested is connected to the detection circuit, the ratio of the second current value to the first current value is a second ratio value, then determining the working state of the relay based on the ratio of the second current value flowing through the loop resistance to the first current value output by the detection power supply includes: within the same time period, if the difference between the change value of the first ratio value and the change value of the second ratio value is greater than a second ratio threshold, determining that at least one of the main positive relay and the main negative relay is in an accelerated aging state.

[0011] In certain embodiments, before determining the working state of the relay based on the ratio of the second current value flowing through the loop resistance to the first current value output by the detection power supply, the method further includes: when the detection circuit is used for the first time, sequentially connecting the first contact pair to be tested with the detection circuit and connecting the second contact pair to be tested with the detection circuit to obtain an initial difference between the first ratio value and the second ratio value; when the detection circuit is used subsequently, sequentially connecting the first contact pair to be tested with the detection circuit and connecting the second contact pair to be tested with the detection circuit to obtain measured differences between the first ratio value and the second ratio value; and determining the difference between a change value of the first ratio value and a change value of the second ratio value based on the initial difference and the measured difference.

[0012] In certain embodiments, when the first contact pair to be tested is connected to the detection circuit, the ratio of the second current value to the first current value is a first ratio value, and when the second contact pair to be tested is connected to the detection circuit, the ratio of the second current value to the first current value is a second ratio value, and the connecting of the corresponding relay and the detection circuit in the load circuit in response to a power-on signal or a power-off signal also includes: in response to the power-on signal, connecting the first contact pair to be tested and the detection circuit multiple times to obtain multiple first ratio values ​​and the change value of the first ratio value each time; or in response to the power-on signal, connecting the second contact pair to be tested and the detection circuit multiple times to obtain multiple second ratio values ​​and the change value of the second ratio value each time. The method of determining the working state of the relay based on the ratio of the second current value flowing through the loop resistor to the first current value output by the detection power supply also includes: when the number of times the change value of the first proportional value is greater than the third proportional threshold reaches a preset number of times and the detection circuit does not detect abnormal current or abnormal voltage impact, determining that there is foreign matter in the contacts of the first contact pair to be tested to determine that the main positive relay has poor contact; or when the number of times the change value of the second proportional value is greater than the third proportional threshold reaches a preset number of times and the detection circuit does not detect abnormal current or abnormal voltage impact, determining that there is foreign matter in the contacts of the second contact pair to be tested to determine that the main negative relay has poor contact.

[0013] In certain embodiments, the relay includes a pre-charge relay, and the third contact pair to be tested of the pre-charge relay is connected in parallel with the first contact pair to be tested. Then, in response to the power-on signal or the power-off signal, the corresponding relay in the load circuit is connected with the detection circuit, and further includes: in response to the power-off signal, the first contact pair to be tested of the main positive relay is connected with the detection circuit, so that the first contact pair to be tested and the loop resistance of the detection circuit are connected in parallel between the detection power supply of the detection circuit. Then, the working state of the relay is determined according to the ratio of the second current value flowing through the loop resistance to the first current value flowing through the detection power supply, and further includes: determining the adhesion of the first contact pair to be tested according to the third ratio of the second current value flowing through the loop resistance to the first current value output by the detection power supply, so as to determine the working state of the main positive relay.

[0014] In certain embodiments, the adhesion condition of the first contact pair to be tested, and then the working state of the main positive relay, is determined based on a third ratio value of the second current value flowing through the loop resistance and the first current value output by the detection power supply, including: when the third ratio value is 1, determining that the first contact pair to be tested and the third contact pair to be tested are not adhered, to determine that the main positive relay is not adhered; or when the third ratio value is less than a fourth ratio threshold, determining that the first contact pair to be tested is adhered, to determine that the main positive relay is adhered.

[0015] In certain embodiments, determining the operating state of the relay based on a ratio of a second current value flowing through the loop resistor to a first current value flowing through the detection power supply includes: when the time for connecting the contact pair to be tested and the detection circuit reaches a preset time, determining the operating state of the relay based on a ratio of the second current value to the first current value.

[0016] In some embodiments, determining the working state of the relay based on the ratio of a second current value flowing through the loop resistor to a first current value flowing through the detection power supply includes: when the ratio of the second current value to the first current value is greater than 1, determining that the connection state between the relay and the detection circuit is abnormal.

[0017] An embodiment of the present application further provides an electronic device, which includes a memory and a processor, wherein the memory is configured to store a computer program, and the processor implements the above-mentioned state assessment method when executing the computer program.

[0018] An embodiment of the present application also provides a state evaluation circuit of a relay, which includes a detection circuit and the above-mentioned electronic device, wherein the detection circuit includes a detection power supply and a loop resistance. When the corresponding relay in the load circuit is connected to the detection circuit, the contact pair to be tested of the relay and the loop resistance of the detection circuit are connected in parallel between the detection power supply of the detection circuit, and the loop resistance matches the contact resistance of the contact pair to be tested when the relay is adhered.

[0019] In some embodiments, the detection circuit includes a bleeder resistor, and the negative electrode of the detection power supply is grounded through the bleeder resistor.

[0020] The present application also provides a load circuit, including a battery, a plurality of relays, a load, and the above-mentioned electronic device or state evaluation circuit. The plurality of relays include a main positive relay and a main negative relay, the positive electrode of the battery is connected to the load through the main positive relay, and the negative electrode of the battery is connected to the load through the main negative relay.

[0021] An embodiment of the present application further provides a vehicle, which may include the electronic device, state evaluation circuit or load circuit of the above embodiment.

[0022] The embodiment of the present application discloses a state evaluation method of a relay, an electronic device, a state evaluation circuit of a relay, a load circuit and a vehicle. The state evaluation method includes: in response to a power-on signal or a power-off signal, connecting the corresponding relay in the load circuit with the detection circuit so that the contact pair to be tested of the relay and the loop resistance of the detection circuit are connected in parallel between the detection power supply of the detection circuit, and the resistance value of the loop resistance matches the resistance value of the contact resistance of the contact pair to be tested when the relay is adhered; determining the working state of the relay according to the ratio of the second current value flowing through the loop resistance to the first current value flowing through the detection power supply.

[0023] In this way, the relay status evaluation method provided in the embodiment of the present application can reflect the slight changes in the contact resistance of the relay at the milliohm level, so as to accurately reflect the working status of the relay.

[0024] Additional aspects and advantages of the embodiments of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0026] Figure 1is a flow chart of a relay status assessment method provided in certain embodiments of the present application;

[0027] Figure 2 is a circuit diagram of a state evaluation circuit and a load circuit of a relay provided in certain embodiments of the present application;

[0028] Figure 3 is a circuit diagram of a state evaluation circuit and a load circuit of a relay provided in certain embodiments of the present application;

[0029] Figure 4 is a flow chart of a relay status assessment method provided in certain embodiments of the present application;

[0030] Figure 5 is a flow chart of a relay status assessment method provided in certain embodiments of the present application;

[0031] Figure 6 is a flow chart of a relay status assessment method provided in certain embodiments of the present application;

[0032] Figure 7 is a flow chart of a relay status assessment method provided in certain embodiments of the present application;

[0033] Figure 8 is a flow chart of a relay status assessment method provided in certain embodiments of the present application;

[0034] Fig. 9 is a flow chart of a relay status assessment method provided in certain embodiments of the present application;

[0035] Fig.10 is a flow chart of a relay status assessment method provided in certain embodiments of the present application;

[0036] Fig.11 is a flow chart of a relay status assessment method provided in certain embodiments of the present application;

[0037] Fig.12 is a flow chart of a relay status assessment method provided in certain embodiments of the present application;

[0038] Fig.13 is a flow chart of a relay status assessment method provided in certain embodiments of the present application;

[0039] Fig.14 It is a schematic diagram of a vehicle according to an embodiment of the present application.

[0040] Description of main component symbols:

[0041] A main positive relay 11 , a main negative relay 12 , a pre-charge relay 13 , a detection circuit 20 , a loop resistor 21 , a detection power source 22 , a battery 30 , a load 40 , an electronic device 100 , a load circuit 200 , and a vehicle 1000 . DETAILED DESCRIPTION

[0042] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions from beginning to end. The embodiments described below with reference to the accompanying drawings are optional and are only used to explain the embodiments of the present application, and cannot be understood as limiting the embodiments of the present application.

[0043] In the related art, in order to detect whether the contacts of the relay are stuck, it is necessary to detect the contact resistance between the contacts of the relay, and determine whether the contacts of the relay are stuck according to the size of the contact resistance between the contacts of the relay. The contact resistance between the contacts of the relay is detected by using the voltage drop method, that is, the contact resistance between the contacts is calculated by measuring the voltage drop across the contact pair of the resistance relay.

[0044] However, since the contact resistance between the contacts of the relay in the electric vehicle distribution box is small (usually in the range of 0.05 milliohms to 5 milliohms), and even if there is adhesion between the contacts, the change in contact resistance between the contacts is small, it is difficult to accurately detect the change in contact resistance, and it is also difficult to determine whether the contacts of the detection relay are adhered based on the size of the contact resistance.

[0045] The embodiment of the present application provides a relay status assessment method, which can accurately reflect the slight changes in the contact resistance of the relay at the milliohm level, so as to accurately reflect the working status of the relay.

[0046] In the relay status assessment method provided in the embodiment of the present application, when the detection circuit is connected to the corresponding relay, the loop resistance and the connected relay can form a parallel equivalent resistance, and the "resistance value of the loop resistance and the resistance value of the parallel equivalent resistance" are related to the "ratio of the second current value to the first current value". The resistance value of the loop resistance can match the contact resistance of the relay contact pair to be tested when adhesion and sintering occur, ensuring that the ratio of the second current value to the first current value can accurately reflect the resistance change between the contact pair to be tested.

[0047] Reference Figure 1 as well as Figure 2The embodiment of the present application provides a load circuit 200, and the relay state evaluation method provided in the embodiment of the present application can be used for the load circuit 200. The load circuit 200 may include multiple relays, a detection circuit 20, a battery 30, and a load 40. The battery 30 and the load 40 may be connected through corresponding relays. The method includes:

[0048] Step 02: In response to a power-on signal or a power-off signal, the corresponding relay in the load circuit 200 is connected to the detection circuit 20, so that the contact pair to be tested of the relay and the loop resistor 21 of the detection circuit 20 are connected in parallel between the detection power supply 22 of the detection circuit 20, and the resistance value of the loop resistor 21 matches the resistance value of the contact resistance of the contact pair to be tested when the relay is adhered;

[0049] Step 03: Determine the working state of the relay according to the ratio of the second current value flowing through the loop resistor 21 to the first current value flowing through the detection power supply 22.

[0050] Reference Figure 2 The plurality of relays may include a main positive relay 11 and a main negative relay 12. The main positive relay 11 may be a switch element S1, and the main negative relay 12 may be a switch element S3. The first contact to be tested may be a connection contact of the switch element S1, and the second contact to be tested may be a connection contact of the switch element S3.

[0051] Optionally, the plurality of relays may further include a pre-charge relay 13, and the pre-charge relay 13 may be a switch element S2. The third contact to be tested may be a connection contact of the switch element S2.

[0052] The positive electrode of the battery 30 is connected to the load 40 through the main positive relay 11, and the negative electrode of the battery 30 is connected to the load 40 through the main negative relay 12. In other words, the positive electrode of the battery 30 can be connected to the positive electrode of the load 40 through the switch element S1, and the negative electrode of the battery 30 can be connected to the negative electrode of the load 40 through the switch element S2.

[0053] Optionally, the pre-charging relay 13 can be connected to the main positive relay 11 through a pre-charging resistor, the pre-charging resistor can be a first resistor R1, the first end of the switching element S2 can be connected to the first end of the switching element S1, and the second end of the switching element S2 can be connected to the second end of the switching element S1 through the first resistor R1.

[0054] The detection circuit 20 may include a first switch element K1 , a second switch element K2 , a third switch element K3 and a fourth switch element K4 , and the load circuit 200 may further include a switch element S4 .

[0055] The positive electrode of the battery 30 can be connected to the switch element S1 through the switch element S4, the first end of the first switch element K1 can be connected to the node between the switch element S4 and the switch element S1, and the second end of the first switch element K1 is connected to the first end of the third switch element K3. The second end of the third switch element K3 is connected to the node between the negative electrode of the battery 30 and the switch element S3, and the first end of the second switch element K2 is connected to the node between the load 40 and the switch element S1. The second end of the second switch element K2 is connected to the first end of the fourth switch element K4, and the second end of the fourth switch element K4 is connected to the node between the load 40 and the switch element S3.

[0056] In the case of starting the state evaluation process of the relay, the detection circuit 20 can be connected to any one of the switch element S1, the switch element S2 and the switch element S3. The battery 30 can be in the off state, or the switch element S4 can be in the off state, so as to prevent the battery 30 from forming a loop through the switch element S4, the load 40, the switch element S1 and the switch element S3, and to prevent the current flowing through the switch element S1, the switch element S2 and the switch element S3 from affecting the result determined by the state evaluation method.

[0057] After the relay status evaluation process is completed, the battery 30 can be in the open state and the switch element S4 can be in the closed state, so that the battery 30 forms a loop through the switch element S4, the load 40, the switch element S1 and the switch element S3, and the battery 30 can supply power to the load 40.

[0058] The loop resistor 21 of the detection circuit 20 can be a second resistor R2. The first end of the second resistor R2 is connected to the node between the first switch element K1 and the third switch element K3, and the second end of the second resistor R2 is connected to the node between the second switch element K2 and the fourth switch element K4. The first end of the detection power supply 22 is connected to the node between the first switch element K1 and the third switch element K3, and the second end of the detection power supply 22 is connected to the node between the second switch element K2 and the fourth switch element K4. The current detection module is respectively connected to the node a of the branch where the detection power supply 22 is located and the node b of the branch where R2 is located.

[0059] In step 02, in response to the power-on signal, the switch element S1 and the switch element S3 may be in a closed state, and the switch element S2 may be in an open state, at which time the first switch element K1 and the second switch element K2 may be controlled to be turned on, or the third switch element K3 and the fourth switch element K4 may be controlled to be turned on. When the first switch element K1 and the second switch element K2 are turned on, the switch element S1 may be connected in parallel with the second resistor R2, and the switch element S2 may be connected in parallel with the second resistor R2 through the first resistor R1. When the third switch element K3 and the fourth switch element K4 are turned on, the switch element S3 may be connected in parallel with the second resistor R2.

[0060] In response to the power-off signal, the switch element S1 and the switch element S3 are in a disconnected state, and the first switch element K1 and the second switch element K2 can be controlled to be turned on. The switch element S1 can be connected in parallel with the second resistor R2 through the first resistor R1, and the switch element S2 can also be connected in parallel with the second resistor R2 through the first resistor R1.

[0061] Of course, even when the switch elements S1, S2 and S3 are all turned off, the corresponding switch elements can be controlled to be turned on in response to the power-on signal or the power-off signal. Since the branch where the second resistor R2 is located is always connected to the loop, the normal operation of the detection circuit 20 is not affected.

[0062] The detection circuit 20 also includes a current detection module, which can determine a first current value I1 by detecting the current value of the current flowing through the node a, and can determine a second current value I2 by detecting the current value of the current flowing through the node b. In order to avoid the detection power supply 22 from generating current drift during long-term operation and thus affecting the evaluation result, the ratio of the second current value to the first current value can be used to evaluate the state of the relay to be tested.

[0063] In step 03, in response to the power-on signal, when the first switch element K1 and the second switch element K2 are turned on, the second resistor R2 is connected in parallel with the switch element S1. At this time, the second current value I2 can be set to I 2-S1 , the current value flowing through the switch element S1 is IS1, and the first current value is I 2-S1 +IS1, at this time the ratio of the second current value to the first current value is P 2-S1 .

[0064] Alternatively, in response to the power-on signal, when the switch element K3 and the switch element K4 are turned on, the second resistor R2 is connected in parallel with the switch element S3, and the second current value I2 can be set to I 2-S3 , the current value flowing through the switch element S3 is IS3, and the first current value is I 2-S3+IS3, at this time the ratio of the second current value to the first current value is P 2-S3 .

[0065] In addition, in response to the power-off signal, when the first switch element K1 and the second switch element K2 are turned on, the second resistor R2 is connected in parallel with the switch element S2. At this time, the second current value I2 can be set to I 2-S2 , the first current value is I 2-S2 +IS2, at this time the ratio of the second current value to the first current value is P 2-S2 .

[0066] The second resistor R2 and the connected relay can form a parallel equivalent resistor, and the "resistance value of the parallel equivalent resistor" is related to the "ratio of the second current value to the first current value". If the resistance value of the second resistor R2 is too small, the ratio of the second current value to the first current value is difficult to accurately reflect the change of the contact resistance of the relay.

[0067] Therefore, the resistance value of the second resistor R2 can be set according to the contact resistance of the switching elements S1, S2 and S3 when adhesion and sintering occur, so as to ensure that the ratio of the second current value to the first current value can accurately reflect the change of the contact resistance of the relay when the contact resistance of the contact to be measured changes.

[0068] The resistance value of the loop resistor matches the resistance value of the contact resistance of the contact pair to be tested when the relay is adhered, that is, the resistance value of the second resistor R2 can match the contact resistance when the switch element S1, the switch element S2, and the switch element S3 are adhered or sintered. The contact resistance when the switch element S1, the switch element S2, and the switch element S3 are adhered or sintered is Rc, and the resistance value of the second resistor R2 can be set to the same value as Rc, or to a value close to Rc.

[0069] The resistance value of the second resistor R2 can also be set to Rc, or the resistance value of the second resistor R2 can be set to a value less than or equal to 2Rc and greater than or equal to 0.5Rc, or the resistance value of the second resistor R2 can be set to a value less than or equal to 4Rc and greater than or equal to 0.2Rc. 2-S1 The change value of can determine the change accuracy of the contact resistance of the switch element S1. The closer the resistance value of the second resistor R2 is to Rc, the higher the contact resistance of the switch element S1. 2-S1 The more obvious the change in the value is, the more accurately it can reflect the change in the contact resistance of the switching element S1.

[0070] Taking the resistance value of the second resistor R2 as Rc as an example, when the second resistor R2 is connected in parallel with the switch element S1, if the switch element S1 is adhered or sintered, the first current value I1 is twice the second current value I2. 2-S1 When the contact resistance of the switch element S1 changes to 0.8Rc, the first current value I1 is 2.25 times the second current value I2. 2-S1 About 0.44, P 2-S1 The change value is about 0.06. When the contact resistance of the switch element S1 changes to 1.25Rc, the first current value I1 is 1.8 times the second current value I2. 2-S1 About 0.56, P 2-S1 The change in value is about 0.06. 2-S1 The change in the value of can determine the situation where the contact resistance of the switching element S1 decreases by 0.2Rc and increases by 0.25Rc, P 2-S1 A change of about 0.06 can be produced.

[0071] Taking the resistance value of the second resistor R2 as 2Rc as an example, when the second resistor R2 is connected in parallel with the switch element S1, if the switch element S1 is adhered or sintered, the first current value I1 is 3 times the second current value I2. 2-S1 When the contact resistance of the switch element S1 changes to 0.8Rc, the first current value I1 is 3.25 times the second current value I2. 2-S1 When the contact resistance of the switch element S1 changes to 1.25Rc, the first current value I1 is 2.8 times the second current value I2. 2-S1 is about 0.36, and the change is about 0.03. 2-S1 The change in the value of can determine the situation where the contact resistance of the switching element S1 decreases by 0.2Rc and increases by 0.25Rc, P 2-S1 A change of about 0.03 can be produced.

[0072] When the switching elements S1, S2, and S3 are adhered or sintered, the contact resistance is in the range of 0.05 milliohms to 5 milliohms, and Rc can be 0.05 milliohms to 5 milliohms. 2-S1 The change in value can determine the situation where the contact resistance of the switching element S1 decreases by 0.2Rc and increases by 0.25Rc, that is, it can reflect the slight change in the contact resistance of the relay at the milliohm level.

[0073] In this way, the relay status evaluation method provided in the embodiment of the present application can reflect the slight changes in the contact resistance of the relay at the milliohm level, so as to accurately reflect the working status of the relay.

[0074] Reference Figure 2 as well as Figure 3 , the embodiment of the present application also provides an electronic device 100, and the load circuit 200 provided in the embodiment of the present application may include the electronic device 100 provided in the embodiment of the present application. The electronic device 100 can be used as the execution subject of the above-mentioned state evaluation method. The electronic device 100 may include a memory and a processor, and the memory is configured to store a computer program. When the processor executes the computer program, it implements the state evaluation method of the embodiment of the present application. Specifically, the processor can execute "Step 02: In response to the power-on signal or the power-off signal, the corresponding relay in the load circuit 200 is connected to the detection circuit 20, so that the contact pair to be tested of the relay and the loop resistance 21 of the detection circuit 20 are connected in parallel between the detection power supply 22 of the detection circuit 20, and the resistance value of the loop resistance 21 matches the resistance value of the contact resistance of the contact pair to be tested when the relay is stuck; Step 03: Determine the working state of the relay according to the ratio of the second current value flowing through the loop resistance 21 to the first current value flowing through the detection power supply 22".

[0075] Reference Figure 2 as well as Figure 3 The load circuit 200 provided in the embodiment of the present application may include the state evaluation circuit provided in the embodiment of the present application. The embodiment of the present application provides a state evaluation circuit, including the above-mentioned detection circuit 20 and the electronic device 100.

[0076] Specifically, the electronic device 100 may further include a control module. When executing the above step 02, the control module may control the on and off of the first switch element K1, the second switch element K2, the third switch element K3 and the fourth switch element K4 in response to a power-on signal or a power-off signal, so as to realize the connection between the switch element S1, the switch element S2 or the switch element S3 and the detection circuit 20, so that the current detection module in the detection circuit 20 can detect the first current value flowing through the detection power supply 22 and the second current value flowing through the loop resistor 21.

[0077] The electronic device 100 may also include a determination module. When executing the above step 03, the determination module can obtain the first current value and the second current value detected by the detection module, and estimate the ratio of the first current value and the second current value to determine the working state of the relay. When the contact resistance of the contact to be measured changes slightly at the milliohm level, the ratio of the second current value to the first current value can accurately reflect the change in the contact resistance of the relay.

[0078] In some embodiments, the detection power supply 22 includes a current source, which is configured to provide a supply current output by the detection power supply 22, or the detection power supply 22 includes a voltage source and a voltage divider resistor, and the positive electrode of the voltage source is connected to the negative electrode of the voltage source through the voltage divider resistor and the loop resistor 21.

[0079] by Figure 2 For example, the detection power supply 22 may include a constant current source Icc, a first end of the constant current source Icc is connected to a node between the first switch element K1 and the third switch element K3, and a second end of the constant current source Icc is connected to a node between the second switch element K2 and the fourth switch element K4.

[0080] by Figure 3 For example, the detection power supply 22 may include a voltage source E1 and a fourth resistor R4, and the constant current source Icc is replaced by a positive electrode of the voltage source E1 connected in series with the fourth resistor R4.

[0081] In some embodiments of the present application, the current of the constant current source Icc may be set to 5-50A to prevent the contact resistance of the first to fourth switching elements K1 to K4 from increasing rapidly during use.

[0082] In some embodiments of the present application, the fourth resistor R4 may be used as a voltage-dividing resistor, and the resistance value of the fourth resistor R4 may be set between 1-10Ω.

[0083] In some embodiments, the detection circuit 20 includes a bleeder resistor, and the negative electrode of the detection power supply 22 is grounded through the bleeder resistor.

[0084] Specifically, Figure 2 or Figure 3 For example, the discharge resistor can be a third resistor R3, and the third resistor R3 is connected between the negative electrode of the detection power supply 22 and the ground electrode. The magnitude range of the third resistor R3 is 20-100Ω. When there is residual pressure in the loop, it can be discharged through the third resistor R3 to avoid the influence of the residual pressure on the relay state detection result. In addition, when any one of the first switch element K1-the fourth switch element K4 is mistakenly connected to the loop, the negative electrode of the battery 30 can also be discharged through the third resistor R3.

[0085] In this way, the relay status assessment method provided in the embodiment of the present application can effectively avoid the influence of residual voltage on the detection result.

[0086] Reference Figure 4 In some embodiments, step 02: in response to a power-on signal or a power-off signal, connecting the corresponding relay in the load circuit 200 with the detection circuit 20, comprises:

[0087] Step 021: in response to a power-on signal, connecting the first contact pair to be tested of the main positive relay 11 with the detection circuit 20, and disconnecting the second contact pair to be tested of the main negative relay 12 from the detection circuit 20; or

[0088] Step 022: In response to the power-on signal, the second contact pair to be tested is connected to the detection circuit 20, and the first contact pair to be tested is disconnected from the detection circuit 20.

[0089] Specifically, Figure 2 For example, when the electronic device 100 executes the above step 021, in response to the power-on signal, the switch element S1 is closed, the first switch element K1 and the second switch element K2 are closed, and the current source Icc is started. At this time, the relay state evaluation method is configured to determine the working state of the main positive relay 11. At least one of the switch element S3, the third switch element K3 or the fourth switch element K4 is disconnected to prevent the current source Icc from forming a loop with the switch element S3, the third switch element K3 and the fourth switch element K4, thereby affecting the current value flowing through the switch element S1.

[0090] When the electronic device 100 performs the above step 022, in response to the power-on signal, the switch element S3 is closed, the third switch element K3 and the fourth switch element K4 are closed, and the current source Icc is started. At this time, the relay state evaluation method is configured to determine the working state of the main negative relay 12. At least one of the switch element S1, the first switch element K1 or the second switch element K2 is disconnected to prevent the current source Icc from forming a loop with the switch element S1, the first switch element K1 and the second switch element K2, thereby affecting the current value flowing through the switch element S3.

[0091] Reference Figure 5 In some embodiments, step 03: determining the working state of the relay according to the ratio of the second current value flowing through the loop resistor 21 to the first current value output by the detection power supply 22, includes:

[0092] Step 0311: when the first ratio value is greater than or equal to the first ratio threshold value, determining that the contact resistance of the first contact pair to be tested is abnormally increased, so as to determine that the main positive relay 11 has poor contact; or

[0093] Step 0312: When the second ratio value is greater than or equal to the first ratio threshold value, determine that the contact resistance of the second contact pair to be tested increases abnormally, so as to determine that the main negative relay 12 has poor contact.

[0094] Specifically, when the first switch element K1 and the second switch element K2 are turned on, the detection circuit 20 can be connected to the switch element S1, and the second current value I2 can be set to I 2-S1 , the current value flowing through the switch element S1 is IS1, and the first current value is I2-S1 +IS1, at this time the first proportional value P 2-S1 For I 2-S1 Ratio value to IS1.

[0095] When the third switch element K3 and the fourth switch element K4 are turned on, the detection circuit 20 can be connected to the switch element S3. At this time, the second current value I2 can be set to I 2-S3 , the current value flowing through the switch element S3 is IS3, and the first current value is I 2-S3 +IS3, at this time the second proportional value P 2-S3 For I 2-S3 Ratio value to IS3.

[0096] First ratio threshold The size of can be determined by the second resistor R2, the first switch element K1, the second switch element K2, the resistance of the switch element S1 when it is stuck, and the resistance of the switch element S2 when it is stuck.

[0097] In step 0311, at the first proportional value P 2-S1 Greater than or equal to the first ratio threshold When the current detection module detects the first proportional value P, the contact resistance of the first contact pair to be tested of the main positive relay 11 increases abnormally, so as to determine that the main positive relay 11 is in an abnormal state. 2-S1 Less than the first ratio threshold When the contact resistance of the first contact pair to be tested of the main positive relay 11 is detected, it is normal to determine that the state of the main positive relay 11 is normal.

[0098] In step 0312, in P 2-S3 Greater than or equal to the first ratio threshold When the current detection module detects that P 2-S3 Less than the first ratio threshold When the contact resistance of the second contact pair to be tested of the main negative relay 12 is detected to be normal, it is determined that the main negative relay 12 is in a normal state.

[0099] Reference Figure 6 In some embodiments, step 03: determining the working state of the relay according to the ratio of the second current value flowing through the loop resistor 21 to the first current value output by the detection power supply 22, includes:

[0100] Step 0313: When the first ratio value is 1, it is determined that the main positive relay 11 has a coil that is not actuated or is not conducting when it is attracted; or

[0101] Step 0314: When the second ratio value is 1, it is determined that the coil of the main negative relay 12 is not actuated or is not conducting when attracted.

[0102] Specifically, in step 0313, the first switch element K1 and the second switch element K2 are turned on, the detection circuit 20 is connected to the switch element S1, and the current value of the second current can be set to I 2-S1 , the current value flowing through the switch element S1 is IS1, and the first current value is I 2-S1 +IS1, at the first proportional value P 2-S1 When I is 1, 2-S1 +IS1=I 2-S1 , that is, it can be considered that IS1 is close to zero. At this time, it can be considered that the main positive relay 11 is not operating or is not conducting when it is attracted.

[0103] In step 0314, the third switch element K3 and the fourth switch element K4 are turned on, the detection circuit 20 is connected to the switch element S3, and the current value of the second current can be set to I 2-S3 , the current value flowing through the switch element S3 is IS3, and the first current value is I 2-S3 +IS3, at the third proportional value P 2-S3 When I is 1, 2-S3 +IS3=I 2-S3 , that is, it can be considered that IS3 is close to zero. At this time, it can be considered that the main negative relay 12 is not operating or is not conducting when it is attracted.

[0104] Reference Figure 7 In some embodiments, step 03: determining the working state of the relay according to the ratio of the second current value flowing through the loop resistor 21 to the first current value output by the detection power supply 22, includes:

[0105] Step 032: In the same time period, if the difference between the change value of the first proportional value and the change value of the second proportional value is greater than the second proportional threshold, it is determined that at least one of the main positive relay 11 and the main negative relay 12 is in an accelerated aging state.

[0106] Specifically, the second ratio threshold The setting is determined by the manufacturer based on the model of the main positive relay 11 and the main negative relay 12, the contact resistance of the relay when sintered, the second resistor R2, the contact resistance of the first switch element K1 to the fourth switch element K4, etc.

[0107] For the main positive relay 11 and the main negative relay 12 of the same batch and the same model, the difference in initial contact resistance between the two can be ignored, that is, the first proportional value P 2-S1 and the second proportional value P 2-S2The initial difference can be ignored. After working for the same period of time, according to the first proportional value P 2-S1 and the second proportional value P 2-S2 The difference between the first ratio value P and the 2-S1 and the second proportional value P 2-S2 The difference in the amount of change.

[0108] In the same time period, when |P 2-S1 -P 2-S3 |≥Second ratio threshold When max(P 2-S1 , P 2-S3 ) The relay to be tested in the corresponding circuit is in an accelerated aging state. The accelerated aging state is generally caused by the difference in the closing and opening sequence of the main positive relay 11 and the main negative relay 12, abnormally large current and voltage shock in the circuit, and possible foreign matter in the contacts.

[0109] max(P 2-S1 , P 2-S3 ) indicates P 2-S1 With P 2-S3 The maximum value among them, if P 2-S1 Greater than P 2-S3 , it is determined that at least the main positive relay 11 is in an accelerated aging state, and there is also a situation where both the main negative relay 11 and the main negative relay 12 are in an accelerated aging state. 2-S3 Greater than P 2-S1 , it is determined that at least the main negative relay 12 is in an accelerated aging state, and there is also a situation where both the main negative relay 11 and the main negative relay 12 are in an accelerated aging state.

[0110] Reference Figure 8 In some embodiments, before step 03: determining the working state of the relay according to the ratio of the second current value flowing through the loop resistor 21 to the first current value output by the detection power supply 22, the method further includes:

[0111] Step 01: When the detection circuit 20 is used for the first time, the first contact pair to be tested is connected to the detection circuit 20 and the second contact pair to be tested is connected to the detection circuit 20 in sequence to obtain an initial difference between the first ratio value and the second ratio value;

[0112] Step 023: When the detection circuit 20 is used subsequently, the first contact pair to be tested is connected to the detection circuit 20 and the second contact pair to be tested is connected to the detection circuit 20 in sequence to obtain the measurement difference between the first ratio value and the second ratio value respectively;

[0113] Step 024: Determine the difference between the change value of the first proportional value and the change value of the second proportional value according to the initial difference and the measured difference.

[0114] Specifically, when the relay is replaced due to an early warning or a fault, the initial contact resistance of the main positive relay 11 and the main negative relay 12 is quite different, and the initial difference cannot be ignored. In addition, considering that the contact resistance of the first switch element K1 to the fourth switch element K4 may also be quite different after running for a period of time, it is necessary to calibrate the circuit where the main positive relay 11 and the main negative relay 12 are located.

[0115] In step 01, the calibration step of the detection circuit 20 can be performed. When the detection circuit 20 is used for the first time, the relay and the different loops of the detection circuit 20 are connected, the current source output current I1 and the current I2 flowing through R2 are obtained respectively, and the first proportional value P in the detection loop of the main positive relay 11 is calculated. 2-S1 The initial value and the second proportional value P in the main negative relay 12 detection circuit 2-S3 The initial value of .

[0116] in, The first ratio value P can be expressed as 2-S1 The initial value of The second ratio value P can be expressed as 2-S3 The initial value, ΔP in An initial difference between the first scale value and the second scale value may be represented.

[0117] In step 023, when the detection circuit 20 is used later, the current source output current I1 and the current I2 flowing through R2 are obtained respectively, and the first proportional value P in the detection loop of the main positive relay 11 is calculated. 2-S1 The measured value and the second proportional value P in the detection circuit of the main negative relay 12 2-S3 The measured value of P 2-S1实测 The first ratio value P can be expressed as 2-S1 The measured value, P 2-S3实测 The second ratio value P can be expressed as 2-S3 The measured value of

[0118] In step 024, if Then the first ratio value P can be determined 2-S1 The initial value is greater than the second proportional value P 2-S3 The initial value of P 2-S1 The equivalent ratio can be set as P 2-S1实测 +ΔP in , P 2-S3 The equivalent ratio can be set as P 2-S3实测 . 2-S1 The equivalent ratio and P 2-S3 Substitute the equivalent ratio of |P 2-S1 -P 2-S3|, and then determine the difference between the change value of the first ratio value and the change value of the second ratio value.

[0119] like Then the second ratio value P can be determined 2-S2 The initial value is greater than the first proportional value P 2-S1 The initial value of P 2-S3 The equivalent ratio can be set as P 2-S3实测 +ΔP in , P 2-S1 The equivalent ratio can be set as P 2-S1实测 . 2-S1 The equivalent ratio and P 2-S3 Substitute the equivalent ratio of |P 2-S1 -P 2-S3 |, and then determine the difference between the change value of the first proportional value and the change value of the second proportional value, thereby eliminating the initial difference between the first proportional value and the second proportional value caused by the difference in initial contact resistance of the loop.

[0120] In this way, the relay status evaluation method provided in the embodiment of the present application can reflect the slight changes in the contact resistance of the relay at the milliohm level, and avoid the influence of power supply drift and loop resistance 21 differences.

[0121] Reference Fig. 9 In some embodiments, the above step 02: connecting the corresponding relay in the load circuit 200 with the detection circuit 20 in response to the power-on signal or the power-off signal, further includes:

[0122] Step 0211: in response to a power-on signal, connect the first contact pair to be tested with the detection circuit 20 for multiple times to obtain multiple first ratio values ​​and a change value of each first ratio value; or

[0123] Step 0221: In response to the power-on signal, connect the second contact pair to be tested with the detection circuit 20 for multiple times to obtain multiple second ratio values ​​and the change value of each second ratio value.

[0124] After the above step 0211, step 03: determining the working state of the relay according to the ratio of the second current value flowing through the loop resistor 21 to the first current value output by the detection power supply 22, further comprising:

[0125] Step 0331: When the number of times the change in the first proportional value is greater than the third proportional threshold reaches a preset number and the detection circuit 20 does not detect abnormal current or abnormal voltage shock, it is determined that there is a foreign object in the contacts of the first contact pair to be tested to determine that the main positive relay 11 has poor contact.

[0126] After the above step 0221, step 03 determines the working state of the relay according to the ratio of the second current value flowing through the loop resistor 21 to the first current value output by the detection power supply 22, and also includes:

[0127] Step 0332: When the number of times the change in the second proportional value is greater than the third proportional threshold reaches a preset number and the detection circuit 20 does not detect abnormal current or abnormal voltage shock, it is determined that there is a foreign object in the contacts of the second contact pair to be tested to determine that the main negative relay 12 has poor contact.

[0128] Specifically, in step 211, when the first switch element K1 and the second switch element K2 are turned on, the detection circuit 20 can be connected to the switch element S1, and the first proportional value P can be obtained N times (8≤N≤20, N is a natural number). 2-S1 And determine the first proportion value P obtained each time 2-S1 The change value of .

[0129] In step 0331 after step 211, the setting of the third proportional threshold is determined by the manufacturer based on the change in contact resistance when various types of foreign matter appear in the contacts of this model of relay, the second resistor R2, the contact resistance of the first switch element K1 to the fourth switch element K4, etc.

[0130] If the first ratio value P 2-S1 In N consecutive tests, P appears 3 or more times. 2-S1 The change value is greater than or equal to the third ratio threshold If the circuit does not detect abnormally large current or voltage shock within 48 hours, the detection is judged as the presence of foreign matter in the contacts of the first contact pair to be tested, that is, the main positive relay 11 has poor contact. At this time, the system immediately issues an abnormal state warning to avoid the occurrence of relay non-conduction failure caused by the continuous deterioration of the contact foreign matter.

[0131] In step 221, when the third switch element K3 and the fourth switch element K4 are turned on, the detection circuit 20 can be connected to the switch element S3, and the second proportional value P can be obtained M times (8≤M≤20, M is a natural number). 2-S3 And determine the second ratio value P obtained each time 2-S3 The change value of .

[0132] In step 0332 after step 221, if the second ratio value P 2-S3 In M consecutive tests, P appears 3 or more times. 2-S3 The change value is greater than or equal to the third ratio threshold If the circuit does not detect abnormally large current or voltage shock within 48 hours, the detection is judged as the presence of foreign matter in the contacts of the second contact pair to be tested, that is, the main negative relay 12 has poor contact. At this time, the system immediately issues an abnormal state warning to avoid the occurrence of relay non-conduction failure caused by the continuous deterioration of the contact foreign matter.

[0133] It should be noted that at this time, even if |P 2-S1 -P 2-S3 |<Second ratio threshold And P 2-S1 and P 2-S3 Both are less than the first ratio threshold It does not affect the judgment results determined in step 0331 and step 0332.

[0134] Reference Fig.10 In some embodiments, the relay further includes a pre-charge relay 13, the third contact pair to be tested of the pre-charge relay 13 is connected in parallel with the first contact pair to be tested, then step 02: in response to a power-on signal or a power-off signal, connecting the corresponding relay in the load circuit 200 with the detection circuit 20, including:

[0135] Step 025: In response to the power-off signal, the first contact pair to be tested of the main positive relay 11 is connected to the detection circuit 20, so that the first contact pair to be tested and the third contact pair to be tested are connected in parallel with the loop resistor 21 of the detection circuit 20 between the detection power supply 22 of the detection circuit 20;

[0136] Step 03: Determine the working state of the relay according to the ratio of the second current value flowing through the loop resistor 21 to the first current value flowing through the detection power supply 22, and further include:

[0137] Step 034: Determine the adhesion condition of the first contact pair to be tested based on the third ratio value of the second current value flowing through the loop resistor 21 and the first current value output by the detection power supply 22 to determine the working state of the main positive relay 11.

[0138] Specifically, in step 025 , in response to the power-off signal, the first switch element K1 and the second switch element K2 may be controlled to be turned on, and the switch element S2 may be connected in parallel with the second resistor R2 via the first resistor R1 .

[0139] In step 034, in response to the power-off signal, when the first switch element K1 and the second switch element K2 are turned on, the detection circuit 20 can be connected to the switch element S2, and the second current value I2 can be set to I 2-S2 , the current value flowing through the switch element S2 is IS2, and the first current value is I 2-S2 +IS2, at this time, the ratio of the second current value to the first current value is a third ratio value P2-S2 .

[0140] The second resistor R2, the first resistor R1 and the switch element S2 connected thereto can form a parallel equivalent resistor, and the "resistance value of the parallel equivalent resistor" is related to the "ratio of the second current value to the first current value". 2-S2 The change of the contact resistance of the pre-charging relay 13 can be accurately reflected, and the working state of the pre-charging relay 13 can be further determined.

[0141] Reference Fig.11 In some embodiments, step 034: determining the adhesion of the first contact pair to be tested according to the third ratio of the second current value flowing through the loop resistor 21 to the first current value output by the detection power supply 22, and then determining the working state of the main positive relay 11, includes:

[0142] Step 0341: when the third ratio value is 1, determine that the first contact pair to be tested and the third contact pair to be tested are not adhered, so as to determine that the main positive relay 11 is not adhered;

[0143] Step 0342: When the third ratio value is less than the fourth ratio threshold value, determine that the first contact pair to be tested is stuck, so as to determine that the main positive relay 11 is stuck.

[0144] Specifically, in response to the power-off signal, when the main positive relay 11 and the main negative relay 12 are both disconnected, the first switch element K1 and the second switch element K2 are closed, the switch element S1 is connected in parallel with the second resistor R2, and the second element S2 is connected in parallel with the second resistor R2 through the first resistor R1, and the switch element S1 and the switch element S2 are in the disconnected state.

[0145] In step 0341, if the third ratio value P 2-S2 is equal to 1, that is, at this time, the first current value is the same as the second current value, and the current flowing through the main positive relay 11 and the pre-charge relay 13 is zero, so the main positive relay 11 and the pre-charge relay 13 are not adhered. When the current detection module detects the current ratio P flowing through the second resistor 2-S1 When it is less than 1, that is, IS1>0, the main positive relay 11 or the pre-charge relay 13 is stuck.

[0146] In step 0342, the fourth ratio threshold The setting can be determined based on the contact resistance of the pre-charging relay 13, the resistance value of the second resistor R2, etc.

[0147] Since the resistance value of the first resistor R1 is much larger than the contact resistance RS1 of the main positive relay 11, the resistance value of the first resistor R1 can be 50-300 ohms, and RS1 can be 0.05-5 milliohms. The current IS1 flowing through the switch element S1 is much larger than the current IS2 flowing through the switch element S2, and the corresponding P 2-S2 Much larger than P 2-S1 Therefore, when P 2-S1 Greater than or equal to the fourth ratio threshold When P 2-S1 Less than When , the main positive relay 11 is stuck.

[0148] However, in actual application, since the resistance value of the first resistor R1 is too large compared to the contact resistance RS1 of the main positive relay 11 and the resistance value of the second resistor R2, even if the pre-filling relay 13 is stuck, the current value IS1 is almost 0, which is almost the same as the current value IS1 when the pre-filling relay 13 is not stuck. In view of the fact that the pre-filling relay 13 rarely sticks in actual operation due to the small current flowing through it and the short working time, it is possible not to judge whether the pre-filling relay 13 is stuck, but only to judge whether the main positive relay 11 is stuck.

[0149] Reference Fig.12 In some embodiments, in step 02: after connecting the corresponding relay in the load circuit 200 with the detection circuit 20 in response to the power-on signal or the power-off signal, the method includes:

[0150] When the time for connecting the contact pair to be tested and the detection circuit 20 reaches the preset time, step 03 is executed: determining the working state of the relay according to the ratio of the second current value to the first current value.

[0151] Specifically, the set time can be set according to the residual voltage inside the detection circuit 20. After step 02 and before step 03, it is necessary to determine whether the time when the switch element is connected to the detection circuit 20 meets the set time. Step 03 is performed only after the time when the switch element is connected to the detection circuit 20 reaches the set time.

[0152] After the time when the switch element connects to the detection circuit 20 reaches the set time, it can ensure that the residual pressure that may exist in the detection circuit 20 is discharged through the third resistor R3 within the set time, so as to avoid the current value obtained by the current detection module drifting when there is residual pressure in the loop, thereby affecting the relay status detection result.

[0153] Reference Fig.13 In some embodiments, step 03: determining the working state of the relay according to the ratio of the second current value flowing through the loop resistor 21 to the first current value flowing through the detection power supply 22, further includes:

[0154] Step 035: When the ratio of the second current value to the first current value is greater than 1, it is determined that the connection state between the relay and the detection circuit 20 is abnormal.

[0155] Specifically, in step 035, when P is detected 2-S1 or P 2-S3 When it is continuously greater than 1, it is determined that one of the first switch element K1 to the fourth switch element K4 is misconnected to the circuit, and it is determined that the connection state between the relay and the detection circuit 20 is abnormal.

[0156] Under normal circumstances, no matter the switch element S1, the switch element S2 or the switch element S3 is in a normal or sticking state, the detection circuit has only one detection power supply 22, so the current I2 flowing through the second resistor R2 is ≤ I1, so P 2-S1 and P 2-S3 ≤1. When the battery 30 is mistakenly connected to the detection circuit 20, additional current may flow through R2, causing P 2-S1 or P 2-S3 is continuously greater than 1. Therefore, when P is detected 2-S1 or P 2-S3 When it is continuously greater than 1, it is determined that one of the first switch element K1 to the fourth switch element K4 is misconnected to the circuit, and it is determined that the connection state between the relay and the detection circuit 20 is abnormal.

[0157] The relay status assessment method and status assessment circuit provided by the embodiments of the present application at least have the following beneficial effects:

[0158] The status assessment method provided in this application can warn of relay closure non-conduction faults caused by foreign matter on the contacts, thereby effectively reducing the property losses caused by such faults.

[0159] The state assessment method provided in the present application can accurately reflect the slight changes in the contact resistance of the main positive relay 11 and the main negative relay 12 to be tested at the milliohm level, and avoids the influence of power supply drift and differences in the loop resistance 21.

[0160] The state evaluation circuit provided in the present application is simple in design and only requires a current detection module to determine the states of adhesion and accelerated aging of the main positive relay 11 , the main negative relay 12 and the pre-charge relay 13 .

[0161] In the system of the electric vehicle, when there is residual voltage at both ends of the main positive relay 11 and the main negative relay 12, the state assessment method provided in the present application can effectively avoid the influence of the residual voltage on the detection result.

[0162] Reference Fig.14The embodiment of the present application also provides a vehicle 1000, which may include the electronic device 100, the state evaluation circuit or the load circuit 200 of the above embodiment. The vehicle 1000 may include all the technical effects of the electronic device 100, the state evaluation circuit and the load circuit 200 of the embodiment of the present application, which will not be described one by one again.

[0163] In the description of this specification, the descriptions with reference to the terms "certain embodiments", "in an example", "exemplarily", etc., mean that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0164] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0165] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are optional and cannot be understood as limitations to the present application. A person skilled in the art can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A relay status assessment method for a load circuit, wherein the load circuit comprises a plurality of relays, characterized in that: The method comprises: In response to a power-on signal or a power-off signal, the corresponding relay in the load circuit is connected to the detection circuit, so that the contact pair to be tested of the relay and the loop resistance of the detection circuit are connected in parallel between the detection power supply of the detection circuit, and the resistance value of the loop resistance matches the resistance value of the contact resistance of the contact pair to be tested when the relay is stuck; The working state of the relay is determined according to a ratio of a second current value flowing through the loop resistor to a first current value flowing through the detection power supply.

2. The evaluation method according to claim 1, characterized in that: The load circuit includes a main positive relay and a main negative relay, a positive connection loop and a negative connection loop, the main positive relay is configured as a relay of the positive connection loop, the main negative relay is configured as a relay of the negative connection loop, and the corresponding relay in the load circuit is connected with the detection circuit in response to a power-on signal or a power-off signal, including: In response to the power-on signal, connecting the first contact pair to be tested of the main positive relay with the detection circuit, and disconnecting the second contact pair to be tested of the main negative relay with the detection circuit; or In response to the power-on signal, the second contact pair to be tested is connected to the detection circuit, and the first contact pair to be tested is disconnected from the detection circuit.

3. The evaluation method according to claim 2, characterized in that: When the first contact pair to be tested is connected to the detection circuit, the ratio of the second current value to the first current value is a first ratio value; when the second contact pair to be tested is connected to the detection circuit, the ratio of the second current value to the first current value is a second ratio value; Then, determining the working state of the relay according to the ratio of the second current value flowing through the loop resistor to the first current value output by the detection power supply includes: In the case where the first ratio value is greater than or equal to the first ratio threshold value, determining that the contact resistance of the first contact pair to be tested is abnormally increased, so as to determine that the main positive relay has poor contact; or When the second ratio value is greater than or equal to the first ratio threshold value, it is determined that the contact resistance of the second contact pair to be tested increases abnormally, so as to determine that the main negative relay has poor contact.

4. The evaluation method according to claim 3, characterized in that: The method of determining the working state of the relay according to the ratio of the second current value flowing through the loop resistor to the first current value output by the detection power supply further includes: When the first ratio value is 1, it is determined that the coil of the main positive relay is not actuated or is not conducting when it is attracted; or When the second ratio value is 1, it is determined that the coil of the main negative relay is not actuated or is not conducting when attracted.

5. The evaluation method according to claim 2, characterized in that: When the first contact pair to be tested is connected to the detection circuit, the ratio of the second current value to the first current value is a first ratio value; when the second contact pair to be tested is connected to the detection circuit, the ratio of the second current value to the first current value is a second ratio value; Then, determining the working state of the relay according to the ratio of the second current value flowing through the loop resistor to the first current value output by the detection power supply includes: In the same time period, if the difference between the change value of the first proportional value and the change value of the second proportional value is greater than a second proportional threshold, it is determined that at least one of the main positive relay and the main negative relay is in an accelerated aging state.

6. The evaluation method according to claim 5, characterized in that: Before determining the working state of the relay according to the ratio of the second current value flowing through the loop resistor to the first current value output by the detection power supply, the method further includes: When the detection circuit is used for the first time, the first contact pair to be tested is connected to the detection circuit and the second contact pair to be tested is connected to the detection circuit in sequence to obtain an initial difference between the first ratio value and the second ratio value; When the detection circuit is used subsequently, the first contact pair to be tested is connected to the detection circuit and the second contact pair to be tested is connected to the detection circuit in sequence to obtain the measurement difference between the first ratio value and the second ratio value respectively; The difference between the change value of the first proportional value and the change value of the second proportional value is determined according to the initial difference value and the measured difference value.

7. The evaluation method according to claim 2, characterized in that: When the first contact pair to be tested is connected to the detection circuit, the ratio of the second current value to the first current value is a first ratio value; when the second contact pair to be tested is connected to the detection circuit, the ratio of the second current value to the first current value is a second ratio value; Then, in response to the power-on signal or the power-off signal, the corresponding relay in the load circuit is connected with the detection circuit, and further includes: In response to the power-on signal, connecting the first contact pair to be tested with the detection circuit for multiple times to obtain multiple first ratio values ​​and a change value of the first ratio value each time; or In response to the power-on signal, connecting the second contact pair to be tested with the detection circuit for multiple times to obtain multiple second ratio values ​​and a change value of the second ratio value each time; Then, determining the working state of the relay according to the ratio of the second current value flowing through the loop resistor to the first current value output by the detection power supply includes: When the number of times that the change value of the first proportional value is greater than the third proportional threshold reaches a preset number and the detection circuit does not detect abnormal current or abnormal voltage impact, it is determined that there is a foreign object in the contacts of the first contact pair to be tested, so as to determine that the main positive relay has poor contact; or When the number of times the change in the second proportional value is greater than the third proportional threshold reaches a preset number and the detection circuit does not detect abnormal current or abnormal voltage shock, it is determined that there is foreign matter in the contacts of the second contact pair to be tested to determine that the main negative relay has poor contact.

8. The evaluation method according to claim 2, characterized in that: The relay further includes a pre-charge relay, a third contact pair to be tested of the pre-charge relay is connected in parallel with the first contact pair to be tested, and the corresponding relay in the load circuit is connected with the detection circuit in response to the power-on signal or the power-off signal, and further includes: In response to a power-off signal, connecting the first contact pair to be tested of the main positive relay with the detection circuit, so that the first contact pair to be tested and the loop resistance of the detection circuit are connected in parallel between the detection power supply of the detection circuit; Then, determining the working state of the relay according to the ratio of the second current value flowing through the loop resistor to the first current value flowing through the detection power supply includes: The adhesion condition of the first contact pair to be tested is determined according to a third ratio value of the second current value flowing through the loop resistor and the first current value output by the detection power supply, so as to determine the working state of the main positive relay.

9. The evaluation method according to claim 8, characterized in that: The method of determining the adhesion condition of the first contact pair to be tested according to a third ratio value of the second current value flowing through the loop resistor and the first current value output by the detection power supply to determine the working state of the main positive relay includes: When the third ratio value is 1, determining that the first contact pair to be tested and the third contact pair to be tested are not adhered, so as to determine that the main positive relay is not adhered; or When the third ratio value is less than a fourth ratio threshold, it is determined that the first contact pair to be tested is stuck, so as to determine that the main positive relay is stuck.

10. The evaluation method according to claim 1, characterized in that: The determining the working state of the relay according to the ratio of the second current value flowing through the loop resistor to the first current value flowing through the detection power supply comprises: When the time for connecting the contact pair to be tested and the detection circuit reaches a preset time, the working state of the relay is determined according to the ratio of the second current value to the first current value.

11. The evaluation method according to claim 1, characterized in that: The determining the working state of the relay according to the ratio of the second current value flowing through the loop resistor to the first current value flowing through the detection power supply comprises: When the ratio of the second current value to the first current value is greater than 1, it is determined that the connection state between the relay and the detection circuit is abnormal.

12. An electronic device, characterized in that: The electronic device includes a memory and a processor, the memory is configured to store a computer program, and the processor implements the state assessment method according to any one of claims 1 to 11 when executing the computer program.

13. A relay state evaluation circuit, characterized in that: The state evaluation circuit includes a detection circuit and the electronic device described in claim 12, the detection circuit includes a detection power supply and a loop resistor, and when the corresponding relay in the load circuit is connected to the detection circuit, the contact pair to be tested of the relay and the loop resistor of the detection circuit are connected in parallel between the detection power supply of the detection circuit, and the resistance value of the loop resistor matches the resistance value of the contact resistance of the contact pair to be tested when the relay is stuck.

14. The state evaluation circuit according to claim 13, characterized in that: The detection circuit includes a discharge resistor, and the negative electrode of the detection power supply is grounded through the discharge resistor.

15. A load circuit, characterized in that: include: Battery and load; A main positive relay and a main negative relay, the positive electrode of the battery is connected to the positive electrode of the connection terminal of the load through the main positive relay, and the negative electrode of the battery is connected to the negative electrode of the connection terminal of the load through the main negative relay; The electronic device according to claim 11, or the state evaluation circuit according to claim 12 or 13.

16. A vehicle, characterized in that: The vehicle comprises the electronic device according to claim 12 , the state evaluation circuit according to claim 13 or 14 , or the load circuit according to claim 15 .

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