Relay control circuit, relay control method, and electric vehicle

Abstract

The application discloses a relay control circuit, a relay control method and an electric vehicle, and relates to the technical field of electric vehicles. The relay control circuit is used for controlling a relay, the relay is arranged on a high-voltage loop of a power battery pack, the relay control circuit comprises a plurality of controllers, the controllers are controllers in any management system of the vehicle, the controllers have power output ends, the power output ends are connected with each other to form a ring-shaped loop, an input end of a coil in the relay is connected with the ring-shaped loop, and an output end of the coil is grounded. According to the application, the plurality of controllers are used for jointly controlling the relay, even if the voltage output by part of the controllers cannot reach the driving requirement of the relay, the remaining controllers with normal output can ensure the normal driving of the relay, the contact of the relay can be effectively closed, the risk of arc drawing is reduced, the sticking of the relay is avoided, and the safety of the vehicle is ensured.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle technology, and in particular to a relay control circuit, a relay control method, and an electric vehicle. Background Technology

[0002] The high-voltage circuit of the power battery pack inside an electric vehicle is typically controlled by a relay. The relay's coil is driven by a controller with a specific voltage to create conductivity. However, when the lead-acid voltage is low or the controller fails at a single point, the relay cannot engage stably, causing gaps between the contacts and making it prone to arcing, leading to relay sticking. Once the relay inside the power battery pack sticks, it cannot disconnect properly, preventing the vehicle from shutting off the power, severely impacting driving safety. Summary of the Invention

[0003] The main objective of this invention is to provide a relay control circuit, a relay control method, and an electric vehicle, aiming to solve the technical problem of unstable relay driving and easy adhesion in the high-voltage circuit of the power battery pack in the prior art.

[0004] To achieve the above objectives, the present invention proposes a relay control circuit for controlling a relay, wherein the relay is disposed on the high-voltage circuit of a power battery pack, and the relay control circuit includes:

[0005] Multiple controllers, wherein each controller is a controller in any management system of the vehicle, each controller has a power output terminal, and each power output terminal is interconnected to form a loop, wherein the input terminal of the coil in the relay is connected to the loop, and the output terminal of the coil is grounded.

[0006] Optionally, the controller includes:

[0007] Power input terminal;

[0008] A switching circuit, with its input terminal connected to the power input terminal and its output terminal connected to the power output terminal;

[0009] The control chip is connected to the switching circuit and is used to control the switching circuit's on / off state.

[0010] Optionally, the switching circuit includes a switching diode, the input terminal of which is connected to the power input terminal and the control chip respectively, and the output terminal of which is connected to the power output terminal.

[0011] Optionally, the controller includes a vehicle controller, a battery management system controller, a motor controller, and a DC-DC controller.

[0012] To achieve the above objectives, the present invention also proposes a relay control method applied to the relay control circuit described above. The relay control circuit includes multiple controllers, each controller having a power output terminal. The relay control method includes:

[0013] When the controller receives a power-on command, it performs a self-test;

[0014] When the controller is in normal self-test or the fault level is within a preset range, it uses the power output terminal to input power to the coil in the relay, causing the relay to close.

[0015] Optionally, each of the controllers has a power input terminal, which is connected to the power output terminal via a switch;

[0016] The step of inputting power to the coil in the relay using the power output terminal includes:

[0017] The controller controls the switch to close, so that the power input terminal is transmitted to the coil in the relay through the power output terminal.

[0018] Optionally, the relay control method further includes:

[0019] The controller acquires the output voltage of the battery in the vehicle.

[0020] When the output voltage is lower than the normal operating voltage, the switch is controlled to open.

[0021] Optionally, the relay control method further includes:

[0022] When the controller receives a power-down command, it controls the switch to open.

[0023] Optionally, after receiving a power-on command and performing a self-test, the controller further includes:

[0024] When the degree of self-detection failure exceeds the preset range, the controller controls the switch to disconnect.

[0025] To achieve the above objectives, the present invention also proposes an electric vehicle, which includes the relay control circuit as described above, or applies the relay control method as described above.

[0026] In this invention, a relay control circuit is used to control a relay located on the high-voltage circuit of the power battery pack. The relay control circuit includes multiple controllers, which can be controllers in any management system within the vehicle. Each controller has a power output terminal, and these power output terminals are interconnected to form a loop. The input terminal of the relay coil is connected to the loop, and the output terminal of the coil is grounded. By employing multiple controllers to jointly control the relay, this invention ensures that even if the voltage output by some controllers fails to meet the relay's driving requirements, the remaining controllers with normal outputs can still guarantee the relay's normal operation. This allows the relay contacts to close effectively, reducing the risk of arcing, preventing relay sticking, and ensuring vehicle safety. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0028] Figure 1 This is a structural diagram of one embodiment of the relay control circuit of the present invention;

[0029] Figure 2 This is a structural block diagram of another embodiment of the relay control circuit of the present invention;

[0030] Figure 3 This is a flowchart illustrating one embodiment of the relay control method of the present invention.

[0031] Explanation of icon numbers:

[0032] label name label name 10 Relay control circuit 50 Loop circuit 20 relay 60 Power input terminal 30 controller 70 Switching circuit 40 Power output terminal 80 control chip

[0033] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0034] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0037] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0038] Reference Figure 1 , Figure 1 This is a structural diagram of one embodiment of the relay control circuit of the present invention. The present invention proposes a first embodiment of the relay control circuit.

[0039] like Figure 1 As shown, in this embodiment, the relay control circuit 10 is used to control the relay 20. The relay 20 is located on the high-voltage circuit of the power battery pack. The relay control circuit 10 includes multiple controllers 30. Each controller 30 is a controller in any management system in the vehicle. Each controller 30 has a power output terminal 40. Each power output terminal 40 is connected to each other to form a loop circuit 50. The input terminal of the coil in the relay 20 is connected to the loop circuit 50, and the output terminal of the coil is grounded.

[0040] Battery packs typically power the drive circuits in electric vehicles, with an output voltage ranging from 300V to 500V. A step-down module can also be connected to the rear of the battery pack to convert the high voltage output to a low voltage, ranging from 3V to 12V. The high-voltage circuit refers to the transmission path of the high voltage output from the battery pack; it can be the connection circuit between the battery pack and the drive circuit, or the connection circuit between the battery pack and the step-down module. Currently, the above values ​​are merely examples and are not intended to limit the performance of the relevant components.

[0041] The power battery pack has positive and negative terminals. In the high-voltage circuit, the circuit connected to the positive terminal is the positive circuit, and the circuit connected to the negative terminal is the negative circuit. Typically, to ensure high-voltage safety in the vehicle, relays 20 are installed in both the positive and negative circuits, enabling rapid switching between high-voltage output and return. This embodiment uses a relay 20 in either circuit as an example for explanation, and does not limit the relay 20 to be located in either the positive or negative circuit.

[0042] The management systems in a vehicle may include a vehicle management system, a battery management system, a motor control system, a step-down management system, or an air conditioning management system, etc. Each management system needs to perform corresponding actions, therefore each has a controller 30 as the control center for coordinating these actions. Therefore, the controller 40 can also be any device in the vehicle with control capabilities. Furthermore, each management system requires power as its driving energy source, so the controller 30 can also be equipped with a power output terminal 40.

[0043] Since the power output terminals 40 are interconnected to form a loop 50, the relay 20 can be activated as long as any power output terminal 40 of the controller 30 has power output. For example, assuming the normal driving voltage of the relay 20 coil is 12V; even if a single controller 30 fails or the input voltage is insufficient, resulting in an output voltage of only 9V, the voltage input to the coil of the relay 20 can still reach 12V under the pull-up effect of the voltage output by the other controllers 30.

[0044] In this embodiment, the relay control circuit 10 includes multiple controllers 30, which can be controllers in any management system of the vehicle. Each controller 30 has a power output terminal 40, and the power output terminals 40 are interconnected to form a loop 50. The input terminal of the coil in the relay 20 is connected to the loop 50, and the output terminal of the coil is grounded. By using multiple controllers 30 to jointly control the relay 20, even if the voltage output by some controllers 30 cannot meet the driving requirements of the relay 20, the remaining controllers 30 with normal outputs can still ensure the normal driving of the relay 20. This allows the contacts of the relay 20 to close effectively, reducing the risk of arcing, preventing the relay 20 from sticking together, and ensuring vehicle safety.

[0045] Reference Figure 2 , Figure 2 This is a structural block diagram of another embodiment of the relay control circuit of the present invention. Based on the above embodiments, the present invention proposes a second embodiment of the relay control circuit.

[0046] In this embodiment, the controller 30 may include a power input terminal 60, a switching circuit 70, and a control chip 80. The input terminal of the switching circuit 70 is connected to the power input terminal 60, and the output terminal of the switching circuit 70 is connected to the power output terminal 40. The control chip 80 is connected to the switching circuit 70 and is used to control the on / off state of the switching circuit 70.

[0047] To facilitate the controller 30's control over the voltage supplied to the relay 20, this embodiment employs a switching circuit 70 to control the power transmission. When the switching circuit 70 is in the ON state, the power input terminal 60 is connected to the power output terminal 40, and the power supplied to the power input terminal 60 flows to the power output terminal 40, and then to the relay 20. When the switching circuit 70 is in the OFF state, the power input terminal 60 and the power output terminal 40 are not connected, and the power supplied to the power input terminal 60 cannot flow to the power output terminal 40.

[0048] The control chip 80 is a built-in component of each management system. It can control the switching circuit 70 to turn on or off by transmitting electrical signals to the switching circuit 70. For example, when the electrical signal is high, the switching circuit 70 is turned on; when the electrical signal is low, the switching circuit 70 is turned off. Of course, the switching circuit 70 can also be turned on when the electrical signal is low and turned off when the electrical signal is high.

[0049] The power input terminal 60 can be a terminal of the line connected to the power pin in the control chip 80. Since the control chip 80 is a component built into the management system itself, the power output terminal 40 can also be a terminal of a component in the switching circuit 70. Therefore, this embodiment only requires adding the components involved in the switching circuit 70, and the adjustment to the whole vehicle circuit is small, making it easy to implement.

[0050] In a specific implementation, the switching circuit 70 can be composed of a diode, a transistor, or a field-effect transistor. Preferably, the switching circuit 70 may include a switching diode, with its input terminal connected to the power input terminal 60 and the control chip 80, and its output terminal connected to the power output terminal 40.

[0051] Switching diodes are characterized by fast switching speed, small size, long lifespan, and high reliability. The time it takes for a switching diode to switch from off (high resistance state) to on (low resistance state) is called the turn-on time; the time from on to off is called the reverse recovery time; the sum of these two times is called the switching time. Generally, the reverse recovery time is longer than the turn-on time, so only the reverse recovery time is given in the specifications of switching diodes. Switching diodes have extremely fast switching speeds; for example, the reverse recovery time of silicon switching diodes is only a few nanoseconds, and that of germanium switching diodes is several hundred nanoseconds.

[0052] In this embodiment, the controller 30 may include a vehicle controller, a battery management system controller, a motor controller, and a DC-DC controller. The systems corresponding to the above four controllers 30 are directly connected to the high-voltage circuit. By using the controllers 30 on the high-voltage architecture as a loop control circuit, the system can quickly respond to the state of the high-voltage circuit.

[0053] Furthermore, the vehicle controller, battery management system controller, motor controller, and DC-DC controller can be interconnected via a CAN bus. After any controller 30 performs a corresponding switching action, it sends the information to the other controllers 30 via the CAN bus, thereby enabling the other controllers to simultaneously perform the corresponding switching actions.

[0054] In this embodiment, by setting up the switching circuit 70, the controller 30 controls the output of the loop circuit 50, requiring minimal adjustment to the original circuit structure and making it easy to implement; moreover, the controller 30 is the controller for each system on the high-voltage architecture, which can quickly respond to the state of the high-voltage circuit, thereby improving the control accuracy of the relay 20.

[0055] Reference Figure 3 , Figure 3 This is a flowchart illustrating one embodiment of the relay control method of the present invention. To achieve the above objectives, the present invention also proposes a relay control method.

[0056] The relay control method is applied to the relay control circuit described above. The relay control circuit includes multiple controllers, each with a power output terminal. The specific structure of the relay control circuit can be found in the aforementioned embodiments.

[0057] In this embodiment, the relay control method includes:

[0058] Step S10: When the controller receives the power-on command, it performs a self-test.

[0059] The relay control circuit includes multiple controllers, and the execution subject in this embodiment is any one of the controllers in the relay control circuit. In fact, each controller can execute the relay control method mentioned in this embodiment.

[0060] The power-on command can be generated by the user when starting the vehicle. The power-on command can be transmitted to each controller via the CAN bus, and each controller can obtain the command on the CAN bus through the CAN interface.

[0061] The self-tests performed by controllers in different systems vary. For example, the vehicle controller can send signals to other connected controllers or sensors and complete a self-test of the communication path by detecting the responses of these other controllers or sensors. The controller in the battery management system can perform self-tests on the battery pack's temperature and voltage. It determines the battery pack's temperature and voltage by receiving detection parameters from temperature and voltage sensors, and then compares the detected values ​​with a reference to determine the self-test result. The self-test steps for each system in the vehicle are based on mature technologies and will not be elaborated upon in this implementation.

[0062] Step S20: When the controller is in normal self-test or the fault level is within the preset range, it uses the power output terminal to input power to the coil in the relay, so that the relay is closed.

[0063] The self-test results can be categorized as normal or faulty. Faults can be further divided into minor and major faults. A minor fault refers to a fault that does not affect the normal operation of the vehicle. When the fault severity is classified as minor, it can be determined that the fault severity is within a preset range. The classification of fault severity can be set according to requirements, and this implementation method does not impose any restrictions on it. Therefore, when the self-test result is normal or a minor fault, it indicates that the vehicle operation will not be affected, it can be powered on normally, and the relay closure can be controlled.

[0064] Continue to refer to Figure 2 To facilitate the controller's control of the voltage supplied to the relay, a switch can be used to control the power transmission. When the switch is in the ON state, the power input terminal and the power output terminal are connected, and the power supplied to the power input terminal flows to the power output terminal and then to the relay. When the switch circuit is in the OFF state, the power input terminal and the power output terminal are not connected, and the power supplied to the power input terminal cannot flow to the power output terminal.

[0065] In a specific implementation, the steps involve inputting power to the coil in the relay using the power output terminal, including: the controller controls the switch to close, so that the power input terminal is transmitted to the coil in the relay through the power output terminal.

[0066] The controller is a built-in component in each management system. It controls the opening and closing of switches by transmitting electrical signals to them. For example, when the electrical signal is high, the switch is on; when the electrical signal is low, the switch is off. Of course, it is also possible for the switch to be on when the electrical signal is low and off when the electrical signal is high.

[0067] In this embodiment, the controller disconnects the control switch when the severity of a self-test fault exceeds a preset range. A severe fault indicates that the fault level exceeds the preset range, meaning that vehicle operation is easily affected and safety is low. For example, if the vehicle controller detects an abnormality in the braking system, it is determined to be a severe fault.

[0068] Because the relay is controlled by a loop circuit, a fault signal needs to be sent to other controllers when the self-test result of any controller exceeds the preset range. Upon receiving the fault signal, the other controllers control the aforementioned switch to open, thereby preventing the relay from closing.

[0069] In this embodiment, the controller disconnects the control switch upon receiving a power-down command. The power-down command can be generated by the user when shutting down the vehicle, or by another controller in the event of a severe fault, such as the aforementioned fault signal. The power-down command can also be transmitted to each controller via the CAN bus, and each controller receives the command from the CAN bus through the CAN interface.

[0070] Vehicles typically also include a battery. The battery provides low voltage to power various low-voltage devices (such as chips). The relay coil is typically supplied with 12V, which is usually supplied by the battery. When the battery voltage is low, the voltage supplied to the relay coil will drop, such as to 9V. At this time, the relay's engagement is unstable, easily creating gaps and arcing, leading to the relay sticking together.

[0071] In this embodiment, the relay control method may further include: the controller acquiring the output voltage of the battery in the vehicle; and the control switch being disconnected when the output voltage is lower than the normal operating voltage.

[0072] To prevent unstable relay engagement, when the battery voltage is too low, the controller directly stops outputting voltage to disconnect the relay. The normal operating voltage is 9V. Of course, if the voltage of the controller closer to the battery connection line can still be maintained above 9V, the switch can remain closed; the controller farther from the lead-acid battery connection line will prioritize disconnecting the relay.

[0073] In this embodiment, when the controller receives a power-on command, it performs a self-test. If the self-test is normal or the fault level is within a preset range, the controller inputs power to the coil in the relay through the power output terminal, causing the relay to close. This invention uses multiple controllers to jointly control the relay. Even if the voltage output by some controllers 30 cannot meet the relay's driving requirements, the remaining controllers with normal outputs can still ensure the relay's normal operation, allowing the relay contacts to close effectively, reducing the risk of arcing, preventing relay sticking, and ensuring vehicle safety.

[0074] To achieve the above objectives, the present invention also proposes an electric vehicle, which includes the relay control circuit as described above, or applies the relay control method as described above. The specific structure of the relay control circuit is as described in the above embodiments, and the specific steps of the relay control method are as described in the above embodiments. Since this electric vehicle can adopt the technical solutions of all the above embodiments, it at least has the beneficial effects brought about by the technical solutions of the above embodiments, and will not be elaborated further here.

[0075] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A relay control circuit, characterized by comprising: For controlling a relay, the relay is disposed on the high-voltage circuit of the power battery pack, and the relay control circuit includes: Multiple controllers are provided, each being a controller in any management system of the vehicle. The controllers include a vehicle controller, a battery management system controller, a motor controller, and a DC-DC controller. Each controller has a power output terminal, and the power output terminals are interconnected to form a loop. The loop is used to provide drive power to the coil of the relay through the power output terminals of the other controllers when the power output terminal of any controller fails. One end of the coil in the relay is connected to the loop, and the other end of the coil is grounded.

2. The relay control circuit of claim 1, wherein, The controller includes: Power input terminal; A switching circuit, wherein the input terminal of the switching circuit is connected to the power input terminal, and the output terminal of the switching circuit is connected to the power output terminal; A control chip, connected to the switching circuit, is used to control the on / off state of the switching circuit.

3. The relay control circuit of claim 2, wherein, The switching circuit includes a switching diode, the input terminal of which is connected to the power input terminal and the control chip, and the output terminal of which is connected to the power output terminal.

4. A relay control method characterized by, The relay control circuit, as described in any one of claims 1-3, comprises a plurality of controllers, each controller having a power output terminal, and the relay control method comprises: When the controller receives a power-on command, it performs a self-test; When the controller performs a normal self-test or the degree of self-test failure is within a preset range, it uses the power output terminal to input drive power to the coil in the relay, thereby closing the relay.

5. The relay control method according to claim 4, wherein Each of the controllers has a power input terminal, which is connected to the power output terminal via a switching circuit; The step of inputting drive power to the coil in the relay using the power output terminal includes: The controller controls the closing of the switching circuit, so that the driving power connected to the power input terminal is transmitted to the coil in the relay through the power output terminal.

6. The relay control method according to claim 5, wherein The relay control method further includes: The controller acquires the output voltage of the battery in the vehicle; When the output voltage is lower than the normal operating voltage, the switching circuit is controlled to disconnect.

7. The relay control method according to claim 5, wherein The relay control method further includes: When the controller receives a power-down command, it controls the switching circuit to disconnect.

8. The relay control method according to claim 5, wherein Upon receiving a power-on command, the controller performs a self-test and then further includes: When the degree of self-detection failure exceeds the preset range, the controller controls the switching circuit to disconnect.

9. An electric vehicle, characterized by The electric vehicle includes a relay control circuit as described in any one of claims 1-3, or applies a relay control method as described in any one of claims 4-8.

Images