Relay state detection circuit and method and application device thereof

Abstract

The embodiment of the invention provides a relay state detection circuit and method and an application device thereof. The circuit comprises a battery pack, a main positive relay, a main negative relay, a quick charge positive relay, a quick charge negative relay and a first voltage detection module. The first end of the main positive relay is connected with the anode of the battery pack, the second end of the main positive relay is connected with the load end, the first end of the main negative relay is connected with the cathode of the battery pack, and the second end of the main negative relay is connected with the load end; the first end of the fast charging positive relay is connected with the second end of the main positive relay, the second end of the fast charging positive relay is connected with the fast charging end, the first end of the fast charging negative relay is connected with the second end of the main negative relay, and the second end of the fast charging negative relay is connected with the fast charging end; the first voltage detection module is connected in parallel with two ends of the fast charging negative relay and is used for determining whether the discharge loop is connected. The adhesion state of the fast charge positive relay is determined through the first voltage detection module, detection after the main relay is closed is not needed, and the circuit structure is simple.

Description

Technical Field

[0001] The present application relates to the field of circuit detection technology, and in particular to a relay state detection circuit, method, and application device thereof. Background Art

[0002] DC fast charging utilizes specialized, off-board charging stations, characterized by high charging power. During vehicle charging, the battery management system monitors relay status and transmits this information to the vehicle via the vehicle's CAN bus. A collision or other unexpected event during charging could cause the fast-charging relay to unexpectedly disconnect from the high current. This unintended disconnection could cause the relay to stick, preventing it from disconnecting, posing a safety risk to the vehicle and personnel. Therefore, relay sticking detection is crucial.

[0003] Existing methods for detecting the status of DC fast-charging relays typically include differential voltage detection and voltage source injection. These methods assume the vehicle is in the upper high-voltage state, with both the main positive and negative relays closed. This makes it impossible to independently detect the status of the fast-charging relay when the main relay is disconnected. Summary of the Invention

[0004] The embodiments of the present application provide a relay state detection circuit, method, and application device thereof, which are used to solve the problem that the state of the fast charging positive relay cannot be detected when the main relay is disconnected.

[0005] In a first aspect, an embodiment of the present application provides a relay state detection circuit, comprising: a battery pack, a main positive relay, a main negative relay, a fast charge positive relay, a fast charge negative relay, and a first voltage detection module;

[0006] The first end of the main positive relay is connected to the positive electrode of the battery pack, the second end of the main positive relay is connected to the load end, the first end of the main negative relay is connected to the negative electrode of the battery pack, and the second end of the main negative relay is connected to the load end;

[0007] The first end of the fast charging positive relay is connected to the second end of the main positive relay, the second end of the fast charging positive relay is connected to the fast charging end, the first end of the fast charging negative relay is connected to the second end of the main negative relay, and the second end of the fast charging negative relay is connected to the fast charging end;

[0008] The first voltage detection module is connected in parallel at both ends of the fast charging negative relay to determine whether the discharge circuit is connected.

[0009] In one embodiment, the circuit further includes: a second voltage detection module and a third voltage detection module;

[0010] A first end of the second voltage detection module is connected to the second end of the main positive relay, and a second end of the second voltage detection module is connected to the second end of the main negative relay, for detecting the voltage across the load end;

[0011] The third voltage detection module is connected in parallel at both ends of the fast charging end and is used to detect the voltage at both ends of the fast charging end.

[0012] In one embodiment, the circuit further includes a first switch and a second switch, and the third voltage detection module includes a first resistor and a second resistor;

[0013] A first end of the first switch is connected to the second end of the main positive relay, and a second end of the first switch is connected to the second voltage detection module;

[0014] The first end of the second switch is connected to the second end of the fast charging positive relay, and the second end of the second switch is connected to the third voltage detection module;

[0015] The first resistor and the second resistor are connected in series.

[0016] In one embodiment, the circuit further includes: a third switch, the first voltage detection module includes: a first diode, a second diode, a third diode, a third resistor, and a fourth resistor;

[0017] A first end of the third switch is connected to the anode of the second diode, a second end of the third switch is connected to the second end of the fast charge negative relay, and the second end of the third switch is grounded;

[0018] The cathode of the second diode is connected to the anode of the first diode;

[0019] A first end of the third resistor is connected to the first power supply and the cathode of the first diode, and a second end of the third resistor is connected to the first end of the fourth resistor and the anode of the first diode;

[0020] The anode of the third diode is connected to the second end of the fourth resistor, and the cathode of the third diode is connected to the first end of the fast charging negative relay.

[0021] In a second aspect, an embodiment of the present application provides a relay state detection method, which is applied to the above-mentioned relay state detection circuit, and the method includes:

[0022] Determining whether the discharge circuit is connected by a first voltage detection module;

[0023] If the discharge circuit is connected, it is determined that the fast charge positive relay is in a sticking state.

[0024] In one embodiment, determining whether the discharge circuit is connected by the first voltage detection module specifically includes:

[0025] Control the fast charge positive relay, fast charge negative relay, main positive relay and main negative relay to disconnect in sequence;

[0026] Controlling the second switch and the third switch to be closed;

[0027] The voltage across the second diode is obtained, and if the voltage across the second diode is equal to the first preset voltage, it is determined that the discharge circuit is connected.

[0028] In one embodiment, the method further comprises:

[0029] Get the load terminal voltage and fast charge terminal voltage;

[0030] The state of the fast charge positive relay is determined according to the load terminal voltage and the fast charge terminal voltage.

[0031] In one embodiment, determining the state of the fast charge positive relay according to the load terminal voltage and the fast charge terminal voltage specifically includes:

[0032] If the absolute value of the difference between the load terminal voltage and the fast charge terminal voltage is less than or equal to the second preset voltage, it is determined that the fast charge positive relay is in a sticking state;

[0033] Otherwise the fast charge positive relay is in the disconnected state.

[0034] In one embodiment, obtaining the load terminal voltage and the fast charge terminal voltage specifically includes:

[0035] Control the fast charge positive relay to be disconnected; among them, the main positive relay, main negative relay and fast charge negative relay are all in the closed state;

[0036] Controlling the first switch and the second switch to be closed;

[0037] The load terminal voltage and the voltage across the second resistor are obtained, and the fast charge terminal voltage is calculated based on the voltage across the second resistor.

[0038] In one embodiment, the method further comprises:

[0039] Get the front-end voltage of the fast-charging negative relay;

[0040] If the voltage at the front end of the fast charge negative relay is within the third preset range, it is determined that the fast charge negative relay is in a sticking state.

[0041] In one embodiment, obtaining the front-end voltage of the fast-charging negative relay specifically includes:

[0042] Control the fast charge positive relay, fast charge negative relay, main positive relay and main negative relay to disconnect in sequence;

[0043] The first power supply injects a third preset voltage;

[0044] Obtain the voltage of the fourth resistor, which is the front-end voltage of the fast-charging negative relay.

[0045] In one embodiment, the method further comprises:

[0046] If the voltage at the front end of the fast charge negative relay exceeds the third preset range and the voltage at the front end of the fast charge negative relay is the third preset voltage, it is determined that the fast charge negative relay is in the disconnected state.

[0047] In a third aspect, an embodiment of the present application provides a battery management system, comprising any of the above-mentioned relay state detection circuits; and / or

[0048] Includes any of the above relay state detection methods.

[0049] In a fourth aspect, an embodiment of the present application provides a vehicle comprising the above-mentioned battery management system.

[0050] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement any of the above-mentioned relay state detection methods.

[0051] In a sixth aspect, an embodiment of the present application provides a computer program product, including a computer program, which implements any of the above-mentioned relay state detection methods when executed by a processor.

[0052] The relay state detection circuit, method and application device provided by the embodiment of the present application include: a battery pack, a main positive relay, a main negative relay, a fast charging positive relay, a fast charging negative relay and a first voltage detection module; the first end of the main positive relay is connected to the positive pole of the battery pack, the second end of the main positive relay is connected to the load end, the first end of the main negative relay is connected to the negative pole of the battery pack, and the second end of the main negative relay is connected to the load end; the first end of the fast charging positive relay is connected to the second end of the main positive relay, the second end of the fast charging positive relay is connected to the fast charging end, the first end of the fast charging negative relay is connected to the second end of the main negative relay, and the second end of the fast charging negative relay is connected to the fast charging end; the first voltage detection module is connected in parallel at both ends of the fast charging negative relay to determine whether the discharge circuit is connected. The connectivity state of the discharge circuit is determined by the first voltage detection module, and then the adhesion state of the fast charging positive relay is determined. If the first voltage detection module determines that the discharge circuit is connected, the fast charging positive relay is in an adhesion state; the present application does not need to detect after the main relay is closed, and the circuit structure is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0054] Figure 1 A schematic structural diagram of a relay state detection circuit provided in one embodiment of the present application;

[0055] Figure 2 A schematic structural diagram of a relay state detection circuit provided in one embodiment of the present application;

[0056] Figure 3 A schematic structural diagram of a relay state detection circuit provided in one embodiment of the present application;

[0057] Figure 4 A flowchart of a relay status detection method provided in one embodiment of the present application;

[0058] Figure 5 A flowchart of a relay status detection method provided in another embodiment of the present application;

[0059] Figure 6 A flowchart of a method for detecting the state of a fast-charging negative relay provided in another embodiment of the present application;

[0060] Figure 7 This is a schematic diagram of the structure of the battery management system provided in this application. Description of the drawings:

[0062] 110, first voltage detection module; 120, second voltage detection module; 130, third voltage detection module; S1, first switch; S2, second switch; S3, third switch; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; D1, first diode; D2, second diode; D3, third diode.

[0063] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0064] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0065] If a new energy vehicle uses a professional, off-board DC fast charger with high charging power, the battery management system must monitor the relay status during the charging process and transmit this information to the entire vehicle via the vehicle's CAN communication. A collision or other unexpected event during the charging process could cause the fast-charging relay to unexpectedly disconnect under high current. This unintended disconnection could cause the relay to stick, preventing it from disconnecting, posing a safety risk to the vehicle and personnel. Therefore, relay sticking detection is crucial.

[0066] Existing methods for detecting the status of DC fast-charging relays typically include differential voltage detection and voltage source injection. These methods assume the vehicle is in the upper high-voltage state, with both the main positive and negative relays closed. This makes it impossible to independently detect the status of the fast-charging relay when the main relay is disconnected. Furthermore, fast-charging relay status detection relies on the output status of the fast-charging station.

[0067] In combination with the above scenario, it can be seen that in the prior art, there is a problem in detecting the status of the fast charging relay that the main relay is disconnected and cannot be detected.

[0068] The relay state detection circuit provided by the embodiment of the present application includes: a battery pack, a main positive relay, a main negative relay, a fast charging positive relay, a fast charging negative relay and a first voltage detection module; the first end of the main positive relay is connected to the positive electrode of the battery pack, the second end of the main positive relay is connected to the load end, the first end of the main negative relay is connected to the negative electrode of the battery pack, and the second end of the main negative relay is connected to the load end; the first end of the fast charging positive relay is connected to the second end of the main positive relay, the second end of the fast charging positive relay is connected to the fast charging end, the first end of the fast charging negative relay is connected to the second end of the main negative relay, and the second end of the fast charging negative relay is connected to the fast charging end; the first voltage detection module is connected in parallel at both ends of the fast charging negative relay to determine whether the discharge circuit is connected. By determining whether the discharge circuit is connected, and then determining the adhesion state of the fast charging positive relay, there is no need to detect when the main relay is closed, and the independent detection of the fast charging relay state can be achieved; secondly, it can improve the relay state detection speed without relying on the power-off timing of the main contactor; the circuit structure is simple, the logic is simple, and the cost is low.

[0069] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0070] The embodiment of the present application provides a relay state detection circuit, such as Figure 1 As shown, Figure 1A schematic diagram of a relay state detection circuit according to an embodiment of the present application. The detection circuit includes: a battery pack, a main positive relay, a main negative relay, a fast charge positive relay, a fast charge negative relay, and a first voltage detection module 110; a first end of the main positive relay is connected to the positive electrode of the battery pack, a second end of the main positive relay is connected to the load terminal, a first end of the main negative relay is connected to the negative electrode of the battery pack, and a second end of the main negative relay is connected to the load terminal; a first end of the fast charge positive relay is connected to the second end of the main positive relay, a second end of the fast charge positive relay is connected to the fast charge terminal, a first end of the fast charge negative relay is connected to the second end of the main negative relay, and a second end of the fast charge negative relay is connected to the fast charge terminal; and the first voltage detection module 110 is connected in parallel across the fast charge negative relay to determine whether the discharge circuit is connected.

[0071] When all the relays on the high-voltage circuit are in a closed state, the fast-charge negative relay is controlled to be disconnected, the fast-charge positive relay, the main positive relay are disconnected, and the main negative relay is commanded to be disconnected at the same time. At this time, the adhesion state of the fast-charge positive relay can be detected by determining the connectivity state of the discharge circuit. If the fast-charge positive relay is in a sticky state, the positive pole of the load end passes through the fast-charge positive relay and the first voltage detection module 110 to the negative pole of the load end, forming a discharge circuit. Therefore, by determining the connectivity state of the discharge circuit, it can be determined whether the fast-charge positive relay is in a sticky state. If the fast-charge positive relay is in a sticky state, the discharge circuit is connected. This embodiment does not need to detect when the main relay is closed, and can realize independent detection of the fast-charge relay state; secondly, it can increase the relay state detection speed without relying on the power-off timing of the main contactor. The fast-charge end is used to connect to the fast-charge charging pile. This embodiment does not rely on the output state of the charging pile side to judge and determine the adhesion state of the fast-charge positive relay.

[0072] In one embodiment, Figure 2 As shown, Figure 2 A schematic diagram of the structure of a relay state detection circuit provided in an embodiment of the present application. The circuit also includes: a third switch S3, and a first voltage detection module 110 includes: a first diode D1, a second diode D2, a third diode D3, a third resistor R3, and a fourth resistor R4; a first end of the third switch S3 is connected to the anode of the second diode D2, a second end of the third switch S3 is connected to the second end of the fast charge negative relay, and the second end of the third switch S3 is grounded; a cathode of the second diode D2 is connected to the anode of the first diode D1; a first end of the third resistor R3 is connected to the first power supply and the cathode of the first diode D1, a second end of the third resistor R3 is connected to the first end of the fourth resistor R4 and the anode of the first diode D1; an anode of the third diode D3 is connected to the second end of the fourth resistor R4, and a cathode of the third diode D3 is connected to the first end of the fast charge negative relay.

[0073] A discharge circuit is formed between the positive electrode of the load end, the fast charging positive relay, the first voltage detection module 110 and the negative electrode of the load end ( Figure 2 The dotted arrow in the figure shows that the discharge circuit is connected by detecting the voltage of the cathode of the second diode D2, that is, the voltage at point A. At this time, the third switch S3 is in a closed state, which can be regarded as the anode of the second diode D2 being grounded. Therefore, the negative voltage drop of the second diode D2 can be judged, that is, the voltage at point A can be collected. If the voltage at point A is -0.7V, the discharge circuit is considered to be in a connected state, and the state of the fast charging positive relay can be determined to be a sticking state. If the voltage at point A is not equal to -0.7V, it is considered that the fast charging positive relay is normally disconnected.

[0074] In one embodiment, Figure 3 As shown, Figure 3 This is a schematic diagram of the structure of a relay state detection circuit provided in one embodiment of the present application. The circuit also includes: a second voltage detection module 120 and a third voltage detection module 130; the first end of the second voltage detection module 120 is connected to the second end of the main positive relay, and the second end of the second voltage detection module 120 is connected to the second end of the main negative relay, for detecting the voltage across the load terminal; the third voltage detection module 130 is connected in parallel across the fast charging terminal for detecting the voltage across the fast charging terminal.

[0075] The relays (main relay and fast charge relay) on the high-voltage circuit are all in the closed state, and the fast charge positive relay is controlled to be disconnected. At this time, the main positive relay, the main negative relay, and the fast charge negative relay are all in the closed state. At this time, the internal and external pressure difference determines the state of adhesion of the DC fast charge positive relay; the first switch S1 and the second switch S2 are controlled to be closed, and the voltage of the load end is sampled through the second voltage detection module 120, and the voltage of the fast charge end is sampled through the third voltage detection module 130. The voltage of the load end and the voltage of the fast charge end should be almost the same in theory, but considering the sampling accuracy and loss issues, the absolute value of the difference between the voltage of the load end and the voltage of the fast charge end is less than or equal to the second preset voltage, because the voltage of the fast charge end is approximately equal to the voltage of the load end only when the voltage value sampled when the fast charge positive relay is closed. Therefore, if the absolute value of the difference between the voltage of the load end and the voltage of the fast charge end is less than or equal to the second preset voltage, it is determined that the state of the fast charge positive relay is in the adhesion state.

[0076] In one embodiment, Figure 3As shown, the circuit also includes a first switch S1 and a second switch S2, and the third voltage detection module 130 includes a first resistor R1 and a second resistor R2; the first end of the first switch S1 is connected to the second end of the main positive relay, and the second end of the first switch S1 is connected to the second voltage detection module 120; the first end of the second switch S2 is connected to the second end of the fast charging positive relay, and the second end of the second switch S2 is connected to the third voltage detection module 130; the first resistor R1 and the second resistor R2 are connected in series.

[0077] The first resistor R1 and the second resistor R2 are voltage divider resistors, so the voltage at the fast charging end can be determined by detecting the voltage value at both ends of the second resistor R2, that is, the voltage at point B. 快充 =VB*(R1+R2) / R2.

[0078] The embodiment of the present application provides a relay state detection method, which is applied to the above relay state detection circuit, such as Figure 4 As shown, Figure 4 This is a flowchart of a relay status detection method provided in one embodiment of the present application. The method includes the following steps:

[0079] Step S402: Determine whether the discharge circuit is connected by a first voltage detection module.

[0080] Specifically, if Figure 2 As shown, if the positive electrode of the load end, the fast charging positive relay, the first voltage detection module 110 and the negative electrode of the load end form a discharge circuit, by determining the connectivity state of the discharge circuit, it can be determined that the fast charging positive relay is in a sticking state.

[0081] Step S404: If the discharge circuit is connected, it is determined that the fast charge positive relay is in a sticking state.

[0082] This embodiment determines the state of the fast-charge positive relay by determining the connectivity of the discharge circuit through the first voltage detection module, eliminating the need for detection after the main relay is closed, enabling independent detection of the fast-charge relay state. Furthermore, this embodiment does not rely on the power-off timing of the main contactor, improving the speed of relay state detection. The fast-charge terminal is used to connect to a fast-charge charging pile, and this embodiment does not rely on the output status of the charging pile to determine the adhesion state of the fast-charge positive relay.

[0083] In one embodiment, step S402 specifically includes the following steps:

[0084] Control the fast charge positive relay, fast charge negative relay, main positive relay and main negative relay to disconnect in sequence.

[0085] The second switch S2 and the third switch S3 are controlled to be closed.

[0086] The voltage across the second diode D2 is obtained. If the voltage across the second diode D2 is equal to the first preset voltage, it is determined that the discharge circuit is connected.

[0087] Specifically, the first preset voltage is -0.7V. In this embodiment, the voltage across the second diode D2 is obtained by sampling. Since the anode of the second diode D2 is grounded, if the discharge circuit is turned on, there is a negative voltage drop in the second diode D2. Therefore, the negative voltage drop of the second diode D2 can be detected to be -0.7V. It can be determined that the fast charging positive relay is in a sticking state. If the negative voltage drop of the second diode D2 is not equal to -0.7V, it is considered that the fast charging positive relay is normally disconnected.

[0088] Optionally, if the negative voltage drop of the second diode D2 is not within the normal sampling range, the collected voltage value is considered invalid, contactor status diagnosis is not performed, and the contactor status is invalid. The abnormal sampling range of the negative voltage drop of the second diode D2 is a voltage interval outside the voltage range when the contactor is closed and open. This range needs to be calculated based on the resistance drift of the actual application circuit over the full temperature range, or obtained through hardware circuit simulation testing.

[0089] In one embodiment, Figure 5 As shown, Figure 5 This is a flowchart of a relay status detection method provided in another embodiment of the present application. The method further includes the following steps:

[0090] Step S510: Obtain the load terminal voltage and the fast charge terminal voltage.

[0091] Step S520: Determine the state of the fast charge positive relay according to the load terminal voltage and the fast charge terminal voltage.

[0092] Specifically, the load end voltage and the fast charging end voltage should be equal in theory. When the allowable error and sampling accuracy exist, the state of the fast charging positive relay can be determined by detecting the load end voltage and the fast charging end voltage, because when the fast charging positive relay is closed, the third voltage detection module 130 can detect the voltage of the fast charging end.

[0093] In one embodiment, step S520 specifically includes:

[0094] If the absolute value of the difference between the load terminal voltage and the fast charge terminal voltage is less than or equal to the second preset voltage, it is determined that the fast charge positive relay is in a sticking state.

[0095] Otherwise the fast charge positive relay is in the disconnected state.

[0096] After step S510, the method further includes:

[0097] Confirm whether the load-end voltage and the fast-charge voltage are within the normal range. If the load-end voltage or the fast-charge voltage is not within the normal sampling range, the collected voltage value is considered invalid, the relay status diagnosis is not performed, and the relay status is invalid. The normal sampling range of the load-end voltage and the fast-charge voltage should be the voltage range calculated after considering the resistance drift of the sampling resistor within the full temperature range. Outside this range, the voltage values of the load-end voltage and the fast-charge voltage are invalid.

[0098] In one embodiment, step S510 specifically includes:

[0099] Control the fast charge positive relay to disconnect; among them, the main positive relay, main negative relay and fast charge negative relay are all in the closed state.

[0100] The first switch S1 and the second switch S2 are controlled to be closed.

[0101] The load terminal voltage and the voltage across the second resistor R2 are obtained, and the fast charging terminal voltage is calculated based on the voltage across the second resistor R2.

[0102] Specifically, if Figure 3 As shown, the first resistor R1 and the second resistor R2 are both voltage divider resistors. By obtaining the voltage across the second resistor R2, that is, the voltage VB at point B, the fast charging end voltage is obtained. The fast charging end voltage formula is: V 快充 =VB*(R1+R2) / R2. If the absolute value of the difference between the load-end voltage VL and the fast-charge-end voltage is less than or equal to a second preset voltage, that is, |VL-VB*(R1+R2) / R2| is less than or equal to the second preset voltage, then the internal and external pressure differential is considered small, and the fast-charge positive relay is determined to be in a stuck state. If the absolute value of the difference between the load-end voltage VL and the fast-charge-end voltage is greater than the second preset voltage, then the internal and external pressure differential is considered large, and the fast-charge positive relay is determined to be in a normally disconnected state.

[0103] Among them, the second preset voltage is the threshold value calculated after considering the sampling accuracy. Theoretically, when there is no accuracy error, the load end voltage and the fast charging end voltage should be almost the same. However, if the sampling accuracy of x% is considered, the second preset voltage is 2*x%*total voltage.

[0104] In one embodiment, Figure 6 This is a flowchart of a method for detecting the state of a fast-charging negative relay provided in another embodiment of the present application. The method further includes the following steps:

[0105] Step S602: Obtain the voltage at the front end of the fast charging negative relay.

[0106] Step S604: If the voltage at the front end of the fast charge negative relay is within a third preset range, it is determined that the fast charge negative relay is in a sticking state.

[0107] In one embodiment, step S602 specifically includes the following steps:

[0108] Control the fast charge positive relay, fast charge negative relay, main positive relay and main negative relay to disconnect in sequence.

[0109] Specifically, when all relays are closed, the controller issues a command to disconnect the relays, and the fast charging positive relay, the fast charging negative relay, the main positive relay and the main negative relay are disconnected in sequence according to the control order.

[0110] The first power source injects a third preset voltage.

[0111] The voltage of the fourth resistor R4 is obtained. The voltage of the fourth resistor R4 is the front-end voltage of the fast-charging negative relay.

[0112] Specifically, if Figure 2 As shown, the first power supply injects a third preset voltage into the front end of the fast charging negative relay through voltage injection. In this embodiment, the third preset voltage is 2.5V. The third preset voltage can be set according to actual conditions and is not limited in this application.

[0113] If the fast-charge negative relay is in a closed state, the voltage at the front end of the fast-charge negative relay can be calculated based on the voltage divider ratio of the third resistor R3 and the fourth resistor R4; if the fast-charge negative relay is in an open state, the voltage at the front end of the fast-charge negative relay should be close to the voltage of the first power supply, i.e., 2.5 V. This application determines the state of the fast-charge negative relay by the voltage values at the front end of the fast-charge negative relay in two different states.

[0114] If the state of the fast charging negative relay is closed, the front-end voltage of the fast charging negative relay can be calculated based on the voltage divider ratio of the third resistor R3 and the fourth resistor R4, that is, the voltage across the fourth resistor R4, that is, the voltage at point A. If the voltage of VA is within the third preset range, that is, VA∈[2.5V*R4 / (R3+R4)-Δ, 2.5V*R4 / (R3+R4)+Δ], it can be determined that the state of the fast charging negative relay is a sticking state. Among them, Δ can be calculated based on circuit simulation or actual hardware circuit theory.

[0115] In one embodiment, the third preset range is calculated to be [1V, 1.7V], and the front-end voltage of the fast-charging negative relay is [1V, 1.7V], then the state of the fast-charging negative relay is considered to be a sticking state.

[0116] Optionally, if the voltage at the front end of the fast charging negative relay is not within the normal sampling range, the collected voltage value is considered invalid, the relay state detection is not performed, and the state of the relay is considered to be an invalid state.

[0117] In one embodiment, the method further comprises:

[0118] If the voltage at the front end of the fast charge negative relay exceeds the third preset range and the voltage at the front end of the fast charge negative relay is the third preset voltage, it is determined that the fast charge negative relay is in the disconnected state.

[0119] An embodiment of the present application provides a battery management system, including any of the above-mentioned relay state detection circuits; and / or including any of the above-mentioned relay state detection methods.

[0120] The battery management system provided in this embodiment can execute the method provided in the above method embodiment. Its implementation principle and technical effects are similar and will not be described in detail in this embodiment.

[0121] Figure 7 This is a schematic diagram of the battery management system provided in this application. Figure 5 As shown, the electronic device 50 provided in this embodiment includes: at least one processor 501 and a memory 502. Optionally, the battery management system 50 further includes a communication component 503. The processor 501, the memory 502 and the communication component 503 are connected via a bus 504.

[0122] In a specific implementation process, at least one processor 501 executes the computer-executable instructions stored in the memory 502, so that the at least one processor 501 performs the above method.

[0123] The specific implementation process of the processor 501 can be found in the above method embodiment. Its implementation principle and technical effects are similar and will not be repeated here in this embodiment.

[0124] In the above embodiments, it should be understood that the processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the present invention may be directly implemented by a hardware processor or implemented by a combination of hardware and software modules in the processor.

[0125] The memory may include a high-speed memory (Random Access Memory, RAM), and may also include a non-volatile memory (NVM), such as at least one disk memory.

[0126] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. Buses can be classified into address buses, data buses, and control buses. For ease of illustration, the buses in the drawings of this application are not limited to just one bus or just one type of bus.

[0127] An embodiment of the present application provides a vehicle, including the above-mentioned battery management system.

[0128] An embodiment of the present application provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement any of the above-mentioned relay state detection methods.

[0129] An embodiment of the present application provides a computer program product, including a computer program, which implements any of the above-mentioned relay state detection methods when executed by a processor.

[0130] The above-mentioned readable storage medium can be implemented by any type of volatile or non-volatile memory device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0131] An exemplary readable storage medium is coupled to a processor so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be an integral part of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist in the device as discrete components.

[0132] The division of units is merely a logical functional division; actual implementations may employ alternative divisions, such as combining or integrating multiple units or components into another system, or omitting or disabling certain features. Furthermore, any direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between devices or units, either through an interface, electrical, mechanical, or other means.

[0133] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0134] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0135] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program code.

[0136] Those skilled in the art will appreciate that all or part of the steps in the above-described method embodiments can be implemented using hardware associated with program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0137] Finally, it should be noted that those skilled in the art will readily identify other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. The present invention is not limited to the precise structure described above and illustrated in the accompanying drawings, and various modifications and variations may be made without departing from the scope thereof. The scope of the present invention is limited solely by the appended claims.

Claims

1. A relay state detection circuit, characterized in that: include: Battery pack, main positive relay, main negative relay, fast charge positive relay, fast charge negative relay and first voltage detection module; The first end of the main positive relay is connected to the positive electrode of the battery pack, the second end of the main positive relay is connected to the load end, the first end of the main negative relay is connected to the negative electrode of the battery pack, and the second end of the main negative relay is connected to the load end; The first end of the fast charging positive relay is connected to the second end of the main positive relay, the second end of the fast charging positive relay is connected to the fast charging end, the first end of the fast charging negative relay is connected to the second end of the main negative relay, and the second end of the fast charging negative relay is connected to the fast charging end; The first voltage detection module is connected in parallel at both ends of the fast charging negative relay to determine whether the discharge circuit is connected.

2. The relay state detection circuit according to claim 1, characterized in that: The circuit further includes: a second voltage detection module and a third voltage detection module; The first end of the second voltage detection module is connected to the second end of the main positive relay, and the second end of the second voltage detection module is connected to the second end of the main negative relay, for detecting the voltage across the load end; The third voltage detection module is connected in parallel at both ends of the fast charging end, and is used to detect the voltage at both ends of the fast charging end.

3. The relay state detection circuit according to claim 2, characterized in that: The circuit further includes a first switch and a second switch, and the third voltage detection module includes a first resistor and a second resistor; The first end of the first switch is connected to the second end of the main positive relay, and the second end of the first switch is connected to the second voltage detection module; The first end of the second switch is connected to the second end of the fast charging positive relay, and the second end of the second switch is connected to the third voltage detection module; The first resistor and the second resistor are connected in series.

4. The relay state detection circuit according to claim 1, characterized in that: The circuit further includes: a third switch, the first voltage detection module includes: a first diode, a second diode, a third diode, a third resistor and a fourth resistor; A first end of the third switch is connected to the anode of the second diode, a second end of the third switch is connected to the second end of the fast charging negative relay, and the second end of the third switch is grounded; The cathode of the second diode is connected to the anode of the first diode; The first end of the third resistor is connected to the first power supply and the cathode of the first diode, and the second end of the third resistor is connected to the first end of the fourth resistor and the anode of the first diode; The anode of the third diode is connected to the second end of the fourth resistor, and the cathode of the third diode is connected to the first end of the fast charging negative relay.

5. A relay status detection method, characterized in that: Applied to the relay state detection circuit according to any one of claims 1 to 4, the method comprising: Determining whether the discharge circuit is connected by a first voltage detection module; If the discharge circuit is connected, it is determined that the fast charging positive relay is in a sticking state.

6. The relay status detection method according to claim 5, characterized in that: Determining whether the discharge circuit is connected by the first voltage detection module specifically includes: Control the fast charge positive relay, fast charge negative relay, main positive relay and main negative relay to disconnect in sequence; Controlling the second switch and the third switch to be closed; The voltage across the second diode is obtained, and if the voltage across the second diode is equal to a first preset voltage, it is determined that the discharge circuit is connected.

7. The relay status detection method according to claim 5, characterized in that: The method further comprises: Get the load terminal voltage and fast charge terminal voltage; The state of the fast charge positive relay is determined according to the load terminal voltage and the fast charge terminal voltage.

8. The relay status detection method according to claim 7, characterized in that: Determining the state of the fast-charge positive relay according to the load terminal voltage and the fast-charge terminal voltage specifically includes: If the absolute value of the difference between the load terminal voltage and the fast charge terminal voltage is less than or equal to a second preset voltage, it is determined that the fast charge positive relay is in a sticking state; Otherwise, the fast charging positive relay is in the disconnected state.

9. The relay status detection method according to claim 7, characterized in that: Obtain the load terminal voltage and fast charge terminal voltage, including: Control the fast charge positive relay to be disconnected; wherein the main positive relay, the main negative relay and the fast charge negative relay are all in a closed state; Controlling the first switch and the second switch to be closed; Obtain the load terminal voltage and the voltage across the second resistor, and calculate the fast charge terminal voltage based on the voltage across the second resistor.

10. The relay status detection method according to claim 5, characterized in that: The method further comprises: Get the front-end voltage of the fast-charging negative relay; If the front-end voltage of the fast-charging negative relay is within a third preset range, it is determined that the fast-charging negative relay is in a sticking state.

11. The relay status detection method according to claim 10, characterized in that: Get the front-end voltage of the fast-charge negative relay, including: Control the fast charge positive relay, fast charge negative relay, main positive relay and main negative relay to disconnect in sequence; The first power supply injects a third preset voltage; Obtain the voltage of the fourth resistor, where the voltage of the fourth resistor is the front-end voltage of the fast-charging negative relay.

12. The relay status detection method according to claim 11, characterized in that: The method further comprises: If the front-end voltage of the fast-charging negative relay exceeds the third preset range and the front-end voltage of the fast-charging negative relay is the third preset voltage, it is determined that the fast-charging negative relay is in the disconnected state.

13. A battery management system, characterized in that: A relay state detection circuit comprising the relay state detection circuit according to any one of claims 1 to 4; and / or The method comprises the relay state detection method according to any one of claims 5 to 12.

14. A vehicle, characterized in that: Including the battery management system according to claim 13.

15. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the relay state detection method according to any one of claims 5 to 12.

16. A computer program product, characterized in that The invention comprises a computer program, which implements the relay state detection method according to any one of claims 5 to 12 when executed by a processor.

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