Fault diagnosis method and device and vehicle

Abstract

The application provides a fault diagnosis method and device and a vehicle. The method comprises the following steps: when the vehicle is powered on and no battery pack loop fault exists in a previous power-on period, a negative electrode contactor is controlled to be closed; a first current value flowing through the negative electrode contactor is detected; and the battery pack loop is diagnosed according to the first current value. The application provides data support for battery pack loop fault positioning, does not need to additionally sample and detect the battery pack voltage through high voltage, has a simple circuit structure, realizes fault detection of the battery pack based on simple current detection, has fast diagnosis speed, and can meet the fault diagnosis demand of the battery pack power supply.

Description

TECHNICAL FIELD

[0001] The vehicle relates to the technical field, and in particular to a fault diagnosis method and device and a vehicle. BACKGROUND

[0002] Before a battery pack provides high-voltage power supply for a whole vehicle, it is necessary to judge whether the high-voltage connection of the battery pack itself is reliable, for example, to judge whether the connection of a high-voltage switch, a battery monomer or a module, and a high-voltage lead-out of the battery is reliable, and when there is a fault, subsequent operations such as pre-charging or charging and discharging cannot be performed.

[0003] At present, to detect whether a battery pack loop is in an open circuit or a sticking condition, an additional whole-pack high-voltage voltage sampling loop is generally used to calculate the total voltage of a monomer battery and an additional battery pack total voltage to perform fault detection. However, the above method increases the number of hardware components, leads to high system complexity, and has complex diagnosis logic, thereby affecting the diagnosis speed. SUMMARY

[0004] The present application aims to at least solve one of the technical problems existing in the prior art.

[0005] To this end, one object of the present application is to provide a fault diagnosis method, which provides data support for fault positioning of a battery pack loop, does not need additional high-voltage sampling to detect the whole-pack voltage of the battery pack, has a simple circuit structure, realizes fault detection of the battery pack based on simple current detection, has fast diagnosis speed, and can meet the fault diagnosis demand of the battery pack power supply.

[0006] To this end, a second object of the present application is to provide a fault diagnosis device.

[0007] To this end, a third object of the present application is to provide a vehicle.

[0008] In order to achieve the above object, an embodiment of the first aspect of the present application provides a fault diagnosis method, which is used for a battery pack loop, and the battery pack loop comprises a negative contactor, and the method comprises the following steps: when a vehicle is powered on and there is no battery pack loop fault in a last power-on period, controlling the negative contactor to be closed; detecting a first current value flowing through the negative contactor; and performing fault diagnosis on the battery pack loop according to the first current value.

[0009] The fault diagnosis method according to the embodiment of the present application detects the first current value flowing through the negative electrode contactor when the vehicle is powered on and there is no battery pack loop fault in the last power-on period, and performs fault diagnosis on the heating contactor in the battery pack loop according to the first current value. The first current value is detected by controlling the on-off of the related devices such as the heating contactor in the battery pack loop, which provides data support for fault positioning of the battery pack loop. No additional high-voltage sampling is required to detect the battery pack voltage, and the circuit structure is simple. The fault detection of the battery pack is realized based on simple current detection, the diagnosis speed is fast, and the fault diagnosis demand of the battery pack power supply can be met.

[0010] In some embodiments, the fault diagnosis on the battery pack loop according to the first current value comprises: determining whether the first current value is greater than a first current threshold; if yes, determining that the battery pack loop has a first type fault; otherwise, controlling the heating contactor to be closed, and performing fault diagnosis on the battery pack loop.

[0011] In some embodiments, the fault diagnosis on the battery pack loop comprises: detecting a second current value flowing through the heating contactor; and performing fault diagnosis on the battery pack loop according to the second current value.

[0012] In some embodiments, the determination that the battery pack loop has a first type fault comprises: determining that the heating contactor in the battery pack loop is faulty and the battery pack loop has no open circuit fault.

[0013] In some embodiments, after the determination that the battery pack loop has a first type fault, the method further comprises: controlling the negative electrode contactor to be opened.

[0014] In some embodiments, the fault diagnosis on the battery pack loop according to the second current value comprises: determining whether the second current value is less than or equal to a second current threshold; if yes, determining that a battery cell in the battery pack loop has a connection fault and / or an external connection of the battery pack has a fault.

[0015] In some embodiments, when the second current value is greater than the second current threshold, the heating contactor is controlled to be opened.

[0016] In some embodiments, the determination that a battery cell in the battery pack loop has a connection fault and / or an external connection of the battery pack has a fault comprises: obtaining a voltage sampling value of the battery cell; when the voltage sampling value is out of a preset voltage threshold range, determining that the battery cell has a connection fault; and when the voltage sampling value is not out of the preset voltage threshold range, determining that the battery cell has a connection fault and / or the external connection of the battery pack has a fault.

[0017] In some embodiments, the battery pack loop further comprises: a positive contactor and a heating device, wherein the heating device and the heating contactor constitute a heating loop, and determining that the last power-on cycle does not have a battery pack loop fault comprises: when the negative contactor, the positive contactor and the heating loop are all in good condition, determining that the last power-on cycle does not have a battery pack loop fault.

[0018] To achieve the above object, embodiments of the second aspect of the present application propose a fault diagnosis device, which comprises: a control module configured to control the negative contactor to be closed when the vehicle is powered on and it is determined that the last power-on cycle does not have a battery pack loop fault; a detection module configured to detect a first current value flowing through the negative contactor; and a diagnosis module configured to diagnose a fault of the heating contactor in the battery pack loop according to the first current value.

[0019] The fault diagnosis device according to the embodiments of the present application detects the first current value flowing through the negative contactor when the vehicle is powered on and the last power-on cycle does not have a battery pack loop fault, diagnoses a fault of the heating contactor in the battery pack loop according to the first current value, detects the first current value by controlling the on-off of the relevant devices such as the heating contactor in the battery pack loop, provides data support for fault positioning of the battery pack loop, does not need to detect the whole-pack voltage of the battery pack by additional high-voltage sampling, has a simple circuit structure, realizes fault detection of the battery pack based on simple current detection, has a fast diagnosis speed, and can meet the fault diagnosis demand of the battery pack power supply.

[0020] To achieve the above object, embodiments of the third aspect of the present application propose a vehicle adopting the fault diagnosis device as described in the above embodiments.

[0021] The vehicle according to the embodiments of the present application detects the first current value flowing through the negative contactor when the vehicle is powered on and the last power-on cycle does not have a battery pack loop fault, diagnoses a fault of the heating contactor in the battery pack loop according to the first current value, detects the first current value by controlling the on-off of the relevant devices such as the heating contactor in the battery pack loop, provides data support for fault positioning of the battery pack loop, does not need to detect the whole-pack voltage of the battery pack by additional high-voltage sampling, has a simple circuit structure, realizes fault detection of the battery pack based on simple current detection, has a fast diagnosis speed, and can meet the fault diagnosis demand of the battery pack power supply.

[0022] Additional aspects and advantages of the present application will be made apparent from the following description of embodiments, which proceeds with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0023] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description of embodiments, taken in conjunction with the accompanying drawings.

[0024] Figure 1 is a structural schematic diagram of a battery pack loop according to an embodiment of the present application;

[0025] Figure 2 is a flowchart of a fault diagnosis method according to an embodiment of the present application;

[0026] Figure 3 is a flowchart of a fault diagnosis method according to an embodiment of the present application;

[0027] Figure 4 is a structural block diagram of a fault diagnosis device according to an embodiment of the present application;

[0028] Figure 5 is a block diagram of a vehicle according to an embodiment of the present application.

[0029] Reference signs: fault diagnosis device 2;

[0030] control module 21; detection module 22; diagnosis module 23;

[0031] vehicle 3. DETAILED DESCRIPTION

[0032] Embodiments of the present application are described in detail below, and the embodiments described with reference to the accompanying drawings are exemplary, and embodiments of the present application are described in detail below.

[0033] In the related art, a battery pack loop with a heating branch judges whether there is an open circuit by collecting a single cell voltage and accumulating a total voltage V1, and collecting a total voltage V2 of an externally applied battery pack, and judging whether a difference between the two exceeds an expected range; or judges whether there is a reliable connection by collecting a total current and a total voltage, and calculating a ratio of a difference between the two at two time points (as a whole pack resistance); or judges whether there is a disconnection by comparing a single cell accumulated internal resistance and a whole pack internal resistance value, and using the above methods requires an additional whole pack high voltage sampling loop on the basis of the original battery pack loop, increases the complexity of the system, and requires additional calculation of the collected parameters, increases the difficulty of system diagnosis, and even affects the diagnosis speed and accuracy, resulting in the battery pack being unable to normally provide high voltage power supply for the whole vehicle.

[0034] Therefore, the fault diagnosis method of the embodiments of the present application judges whether there is a disconnection or adhesion of the battery pack loop by using a current detection method, the diagnosis logic is relatively simple, meets the rapid diagnosis before the battery pack provides high voltage power supply for the whole vehicle, and can be combined with other existing connection state detection methods, does not require an additional whole pack high voltage sampling loop, reduces the number of hardware components and reduces the complexity of the system, and can locate to a specific fault point to facilitate later fault troubleshooting.

[0035] Let's combine the following... Figure 1 An example of the battery pack circuit in an embodiment of the present invention will be provided.

[0036] like Figure 1 As shown, the battery pack circuit includes: battery pack, BMS (Battery Management System), positive contactor, negative contactor, heating contactor, precharge contactor, heating device, precharge resistor, load and current detection device, wherein,

[0037] The series branch of the pre-charge contactor and the pre-charge resistor is connected in parallel with the positive contactor to form a pre-charge circuit. This circuit is used to pre-charge the vehicle load after diagnosing that there are no abnormal faults in the battery pack circuit, thus preventing current surges. The series branch of the heating device and the heating contactor forms a heating circuit, which is used to heat the battery pack. The current detection device is connected in series with the battery pack to detect the current in the battery pack circuit.

[0038] If the battery pack circuit does not have a heating device, a power resistor can be used instead of a heating device. The heating contactor can be replaced by other controllable switching components such as a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). The selection of power resistors and MOSFETs can be based on the specific project and matched with the threshold current monitored by the BMS.

[0039] The following is combined Figures 1-3 This invention describes a fault diagnosis method according to an embodiment of the present invention.

[0040] like Figure 2 As shown, the fault diagnosis method of this embodiment of the invention includes at least steps S1-S3.

[0041] Step S1: When the vehicle is powered on and there was no battery pack circuit fault in the previous power-on cycle, the negative contactor is closed.

[0042] Among them, battery pack circuit faults include faults in the negative contactor, positive contactor, and heating circuit. If there is no battery pack circuit fault in the previous power-on cycle, it is assumed that there is no fault in the battery pack circuit of the previous power-on cycle. Then, the negative contactor is closed to perform fault diagnosis on the battery circuit of the current power-on cycle.

[0043] In this embodiment, after the vehicle is powered on and the BMS initializes and starts, it determines whether there was a battery pack circuit fault in the previous power-on cycle. If there was a battery pack circuit fault in the previous power-on cycle, no battery pack circuit fault diagnosis is performed, and the battery pack cannot perform the operation of providing high-voltage power supply to the vehicle. It also determines whether there is a serious fault in the BMS and the battery pack itself in the current power-on cycle. If there is a fault, the battery pack cannot perform the operation of providing high-voltage power supply to the vehicle and reports the relevant fault to the vehicle through CAN (Controller Area Network) communication and other means. If there was no battery pack circuit fault in the previous power-on cycle, the negative contactor is closed.

[0044] Step S2: Detect the first current value flowing through the negative contactor.

[0045] In an embodiment, such as Figure 1 As shown, after the negative contactor is closed, the current detection device detects the first current value flowing through the negative contactor, for example, denoted as I1. Based on the first current value I1, the heating contactor in the battery pack circuit is diagnosed for faults. This enables the specific fault point to be located when a fault occurs in the battery pack circuit, facilitating subsequent fault investigation. By combining the existing current detection device to diagnose whether there is a fault in the battery pack circuit, the impact on the accuracy and speed of the system when using an additional full-pack high-voltage sampling circuit is avoided.

[0046] Step S3: Perform fault diagnosis on the battery pack circuit based on the first current value.

[0047] In this embodiment, after obtaining the first current value I1 flowing through the negative contactor, the first current value I1 flowing through the negative contactor is compared with a current threshold, for example, denoted as I. set The relationship between the magnitudes is used to diagnose faults in the heating contactor of the battery pack circuit. If the heating contactor in the battery pack circuit is not faulty, fault diagnoses are performed on other paths in the battery pack circuit, based on the first current value I1 and the current threshold I. set By analyzing the magnitude relationship between the components, fault diagnosis of the battery pack circuit can be performed, which can pinpoint the specific fault point in the battery pack circuit, thus facilitating subsequent fault investigation.

[0048] According to the fault diagnosis method, when the vehicle is powered on and there is no battery pack loop fault in the last power-on period, the first current value flowing through the negative electrode contactor is detected, the heating contactor in the battery pack loop is diagnosed according to the first current value, and when the heating contactor has no fault, the other paths of the battery pack loop are diagnosed. The first current value is detected by controlling the on-off of the related devices such as the heating contactor in the battery pack loop, which provides data support for fault positioning of the battery pack loop, facilitates later fault troubleshooting, does not need additional high-voltage sampling to detect the battery pack voltage, has a simple circuit structure, and uses a simple current detection method to diagnose the battery pack loop, has a fast diagnosis speed, and meets the rapid diagnosis before the battery pack provides high-voltage power supply for the vehicle.

[0049] In some embodiments, the fault diagnosis of the battery pack loop according to the first current value comprises: determining whether the first current value is greater than a first current threshold value; if yes, determining that the battery pack loop has a first type fault; otherwise, controlling the heating contactor to be closed, and diagnosing the fault of the battery pack loop.

[0050] In an embodiment, after the current detection device detects the first current value I1 flowing through the negative electrode contactor, the fault diagnosis of the heating contactor in the battery pack loop is performed according to the first current value I1, the size relationship between the first current value I1 and a first current threshold value I set is determined, if the first current value I1 is greater than the first current threshold value I set , that is, I1>I set , it is considered that the battery pack loop has a first type fault, and the first type fault is reported to the vehicle end through CAN (Controller Area Network) communication or the like; if the first current value I1 is less than or equal to the first current threshold value I set , that is, I1≤I set , it is considered that the heating contactor in series with the negative electrode contactor has no fault, and then the heating contactor is controlled to be closed, and the fault diagnosis of other paths of the battery pack loop, such as the battery monomer and / or the external connection of the battery pack, is performed, so that when the fault diagnosis of the battery pack loop is performed, the specific fault point can be accurately located, and the later fault troubleshooting is facilitated.

[0051] It should be noted that the calculation formula of the first current threshold value I set is as follows:

[0052] I set =V pack / -△I

[0053] Wherein, R is the rated resistance value of the heating device or other elements such as selected power resistor, and β is the resistance correction coefficient considering the influence of factors such as temperature, and the specific value of β can be determined by offline parameter calibration, so as to match the first current threshold I under different temperature conditions and the like set ; V pack The value of V is the minimum total voltage value of the whole pack excluding the influence of voltage sampling, for example, for the lithium iron phosphate battery monomer with a cutoff voltage of about 2.0V, V pack = 2*number of battery pack strings (V). The cumulative value of the current monomer sampling voltage can also be used. ΔI is the detection error of the current detection device, and by determining the maximum resistance correction coefficient β and the maximum detection error ΔI, a minimum first current threshold I set .

[0054] In some embodiments, the battery pack loop is diagnosed for faults, including: detecting a second current value flowing through the heating contactor; and diagnosing the battery pack loop for faults according to the second current value.

[0055] In embodiments, as shown in Figure 1 , after the heating contactor is controlled to be closed, the current detection device detects a second current value flowing through the heating contactor, for example, denoted as I2, so as to diagnose the battery monomer and / or the external connection of the battery pack for faults according to the second current value I2, and when the above-mentioned device fails, the specific fault point can be located, so as to facilitate later troubleshooting.

[0056] In some embodiments, determining that the battery pack loop has a first type of fault includes: determining that the heating contactor in the battery pack loop fails and that the battery pack loop has no open circuit fault.

[0057] In embodiments, if the first current value I1 is greater than the first current threshold I set , i.e., I1>I set , it is considered that the heating contactor in the battery pack loop has a sticking fault, and the related circuit of the battery pack loop has no open circuit fault, and then it is determined that the battery pack loop has a first type of fault.

[0058] In some embodiments, after it is determined that the battery pack loop has a first type of fault, the method further includes: controlling the negative contactor to be opened.

[0059] In embodiments, after it is determined that the battery pack loop has a first type of fault, the negative contactor is controlled to be opened, so as to disconnect the path for providing high-voltage power supply for the vehicle by the battery pack, and prevent safety accidents caused by power-on failure.

[0060] In some embodiments, the fault diagnosis on the battery pack loop according to the second current value comprises: determining whether the second current value is less than or equal to a second current threshold value; if yes, determining that a connection fault occurs in the battery cell in the battery pack loop and / or a fault occurs in the external connection of the battery pack.

[0061] In an embodiment, after the current detection device detects the second current value I2 flowing through the heating contactor, it is determined whether the second current value I2 and the second current threshold value, for example, denoted as I set If the second current value I2 is less than or equal to the second current threshold value I set , that is, I2≤I set , it is considered that a connection fault occurs in the battery cell in the battery pack loop and / or a disconnection fault occurs in the external connection of the battery pack, and the related fault is reported to the vehicle end through CAN (Controller Area Network) communication or the like.

[0062] In some embodiments, when the second current value is greater than the second current threshold value, the heating contactor is controlled to be disconnected.

[0063] In an embodiment, if the second current value I2 is greater than the second current threshold value I set , that is, I2>I set , it is considered that no fault exists in the battery pack loop, and then the heating contactor is controlled to be disconnected, the pre-charging contactor is controlled to be closed, the vehicle end load is pre-charged, and the battery pack performs the operation of providing high-voltage power supply for the vehicle.

[0064] In some embodiments, determining that a connection fault occurs in the battery cell in the battery pack loop and / or a fault occurs in the external connection of the battery pack comprises: obtaining a voltage sampling value of the battery cell; when the voltage sampling value exceeds a preset voltage threshold range, determining that a connection fault occurs in the battery cell; and when the voltage sampling value does not exceed the preset voltage threshold range, determining that a connection fault occurs in the battery cell and / or a fault occurs in the external connection of the battery pack.

[0065] In an embodiment, if the second current value I2 is less than or equal to the second current threshold value I set , that is, I2≤I set , the voltage sampling value of the battery cell is obtained, and the size relationship between the voltage sampling value and the preset voltage threshold range is determined. When the voltage sampling value exceeds the preset voltage threshold range, it is considered that a disconnection abnormality exists in the connection of the two battery cells, and then it is determined that a connection fault occurs in the battery cell. When the voltage sampling value does not exceed the preset voltage threshold range, it is considered that a disconnection abnormality exists in the connection of the two battery cells and / or an abnormality exists in the vehicle end load, and then it is determined that a connection fault occurs in the battery cell and / or a fault occurs in the external connection of the battery pack.

[0066] In some embodiments, the battery pack loop further comprises: a positive contactor and a heating device, wherein the heating device and the heating contactor constitute a heating loop, and the determining that the last power-on cycle does not have the battery pack loop fault comprises: when the negative contactor, the positive contactor and the heating loop are all in good condition, determining that the last power-on cycle does not have the battery pack loop fault.

[0067] In embodiments, after the vehicle is powered on and the BMS initialization is started, it is determined whether the last power-on cycle has the battery pack loop fault, i.e., whether the negative contactor has the open circuit fault, whether the positive contactor has the adhesion fault, and whether the heating loop has the open circuit fault, and when the negative contactor, the positive contactor and the heating loop are all in good condition, it is determined that the last power-on cycle does not have the battery pack loop fault; and when any one of the negative contactor, the positive contactor and the heating loop has a fault, it is determined that the last power-on cycle has the battery pack loop fault.

[0068] Reference will be made to the following Figure 3 The fault diagnosis method of embodiments of the present application is exemplified.

[0069] As shown in the accompanying drawings, Figure 3 The fault diagnosis method of embodiments of the present application at least includes steps S11-S28.

[0070] Step S11, the vehicle is powered on.

[0071] Step S12, it is determined whether the negative contactor, the positive contactor and the heating loop are in good condition, if yes, step S14 is executed; otherwise, step S13 is executed.

[0072] Step S13, it is determined that the last power-on cycle has the battery pack loop fault.

[0073] Step S14, it is determined that the last power-on cycle does not have the battery pack loop fault.

[0074] Step S15, the negative contactor is controlled to be closed.

[0075] Step S16, a first current value flowing through the negative contactor is detected.

[0076] Step S17, it is determined whether the first current value is greater than a first current threshold, if yes, step S18 is executed; otherwise, step S21 is executed.

[0077] Step S18, it is determined that the heating contactor in the battery pack loop has a fault and the battery pack loop does not have an open circuit fault.

[0078] Step S19, it is determined that the battery pack loop has a first type of fault.

[0079] Step S20, the negative contactor is controlled to be opened.

[0080] Step S21: Control the heating contactor to close.

[0081] Step S22: Detect the second current value flowing through the heating contactor.

[0082] Step S23: Determine whether the second current value is less than or equal to the second current threshold. If yes, proceed to step S25; otherwise, proceed to step S24.

[0083] Step S24: Control the heating contactor to disconnect.

[0084] Step S25: Obtain the voltage sampling value of the battery cell.

[0085] Step S26: Determine whether the voltage sample value is within the preset voltage threshold range. If yes, proceed to step S27; otherwise, proceed to step S28.

[0086] Step S27: Determine that a connection fault has occurred in a single battery cell.

[0087] Step S28: Determine that there is a connection failure in the individual battery cell and / or a failure in the external connection of the battery pack.

[0088] According to the fault diagnosis method of the present invention, when the vehicle is powered on and there is no battery pack circuit fault in the previous power-on cycle, the first current value flowing through the negative contactor is detected, and the heating contactor in the battery pack circuit is diagnosed based on the first current value. When there is no fault in the heating contactor, the other paths of the battery pack circuit are diagnosed. By controlling the on / off of relevant devices in the battery pack circuit, such as the heating contactor, the first current value is detected, providing data support for battery pack circuit fault location, facilitating subsequent fault investigation. No additional high-voltage sampling detection of the entire battery pack voltage is required, the circuit structure is simple, and a relatively simple current detection method is used to diagnose the battery pack circuit, resulting in fast diagnosis speed and meeting the requirement for rapid diagnosis before the battery pack provides high-voltage power supply to the vehicle.

[0089] The following is combined Figure 4 The fault diagnosis device 2 of this invention is described in an embodiment.

[0090] like Figure 4 As shown, the fault diagnosis device 2 of this embodiment includes a control module 21, a detection module 22, and a diagnosis module 23, wherein...

[0091] The control module 21 is used to control the negative contactor to close when the vehicle is powered on and it is determined that there is no battery pack circuit fault in the previous power-on cycle; the detection module 22 is used to detect the first current value flowing through the negative contactor; the diagnosis module 23 is used to diagnose the battery pack circuit fault based on the first current value.

[0092] In an embodiment, the control module 21 determines whether there is a battery pack loop fault in the last power-on period after the BMS initialization start, and when there is a battery pack loop fault in the last power-on period, does not perform battery pack loop fault diagnosis, and the battery pack cannot perform the operation of providing high-voltage power supply for the whole vehicle, and determines whether there is a serious fault in the BMS and the battery pack itself in the current power-on period, and when there is a fault, the battery pack cannot perform the operation of providing high-voltage power supply for the whole vehicle, and reports the related fault to the whole vehicle end through CAN (Controller Area Network, Controller Area Network Bus) communication and the like; when there is no battery pack loop fault in the last power-on period, the control negative contactor is closed. Wherein, the battery pack loop fault for example includes faults of the negative contactor, the positive contactor and the heating loop, when there is no battery pack loop fault in the last power-on period, it is considered that the battery pack loop in the last power-on period has no fault, and then the negative contactor is controlled to be closed, and the fault diagnosis of the battery loop in the current power-on period is performed.

[0093] The detection module 22 detects the first current value flowing through the negative contactor, for example, denoted as I1, so as to perform fault diagnosis of the heating contactor in the battery pack loop according to the first current value I1, and when the battery pack circuit has a fault, the specific fault point can be located, so as to facilitate later fault troubleshooting. By combining the existing current detection device to diagnose whether the battery pack loop has a fault, the influence on the accuracy and rapidity of the system when an additional whole-pack high-voltage voltage sampling loop is used is avoided.

[0094] The diagnosis module 23 performs fault diagnosis of the heating contactor in the battery pack loop according to the size relationship between the first current value I1 flowing through the negative contactor and the current threshold value, for example, denoted as I set When the heating contactor in the battery pack loop has no fault, the fault diagnosis of other paths of the battery pack loop is performed, and by performing fault diagnosis of the battery pack loop according to the size relationship between the first current value I1 and the current threshold value I set , the specific fault point of the battery pack loop can be located, so as to facilitate later fault troubleshooting.

[0095] The fault diagnosis device 2 according to the embodiment of the application detects the first current value flowing through the negative contactor when the vehicle is powered on and there is no battery pack loop fault in the last power-on cycle, performs fault diagnosis on the heating contactor in the battery pack loop according to the first current value, and performs fault diagnosis on other paths of the battery pack loop when there is no fault in the heating contactor. By controlling the on-off of related devices such as the heating contactor in the battery pack loop, the first current value is detected to provide data support for fault positioning of the battery pack loop, facilitate later troubleshooting, and there is no need for additional high-voltage sampling to detect the battery pack voltage. The circuit structure is simple, and the battery pack loop is diagnosed by using a simpler current detection method, the diagnosis speed is fast, and the rapid diagnosis before the battery pack provides high-voltage power supply for the vehicle is met.

[0096] In some embodiments, when the diagnosis module 23 performs fault diagnosis on the battery pack loop according to the first current value, the diagnosis module 23 is specifically configured to: determine whether the first current value is greater than a first current threshold value; if yes, determine that the battery pack loop has a first type of fault; and otherwise, control the heating contactor to be closed and perform fault diagnosis on the battery pack loop.

[0097] In some embodiments, when the diagnosis module 23 performs fault diagnosis on the battery pack loop, the diagnosis module 23 is specifically configured to: detect a second current value flowing through the heating contactor; and perform fault diagnosis on the battery pack loop according to the second current value.

[0098] In some embodiments, when the diagnosis module 23 determines that the battery pack loop has the first type of fault, the diagnosis module 23 is specifically configured to: determine that the heating contactor in the battery pack loop has a fault and the battery pack loop has no open circuit fault.

[0099] In some embodiments, after the diagnosis module 23 determines that the battery pack loop has the first type of fault, the diagnosis module 23 is specifically configured to: control the negative contactor to be opened.

[0100] In some embodiments, when the diagnosis module 23 performs fault diagnosis on the battery pack loop according to the second current value, the diagnosis module 23 is specifically configured to: determine whether the second current value is less than or equal to a second current threshold value; if yes, determine that a battery cell in the battery pack loop has a connection fault and / or an external connection of the battery pack has a fault.

[0101] In some embodiments, when the diagnosis module 23 determines that the second current value is greater than the second current threshold value, the diagnosis module 23 is specifically configured to: control the heating contactor to be opened.

[0102] In some embodiments, the diagnostic module 23 is configured to determine the connection fault of the battery cell in the battery pack loop and / or the external connection fault of the battery pack when the battery cell is determined to have the connection fault and / or the external connection fault of the battery pack is determined to have the fault, specifically configured to: acquire the voltage sampling value of the battery cell; and determine that the battery cell has the connection fault when the voltage sampling value is out of the preset voltage threshold range. When the voltage sampling value is not out of the preset voltage threshold range, it is determined that the battery cell has the connection fault and / or the external connection fault of the battery pack is determined to have the fault.

[0103] In some embodiments, the control module 21 is configured to determine that there is no fault of the battery pack loop in the last power-on period when the negative electrode contactor, the positive electrode contactor and the heating loop are determined to have no fault, specifically configured to: determine that there is no fault of the battery pack loop in the last power-on period when the negative electrode contactor, the positive electrode contactor and the heating loop are determined to have no fault.

[0104] According to the fault diagnosis device 2 of the embodiments of the present application, when the vehicle is powered on and there is no fault of the battery pack loop in the last power-on period, the first current value flowing through the negative electrode contactor is detected, the heating contactor in the battery pack loop is diagnosed for fault according to the first current value, when the heating contactor has no fault, the other paths of the battery pack loop are diagnosed for fault, the first current value is detected by controlling the on-off of the related devices such as the heating contactor in the battery pack loop, data support is provided for fault positioning of the battery pack loop, which facilitates later fault troubleshooting, does not need additional high-voltage sampling to detect the whole-pack voltage of the battery pack, the circuit structure is simple, and the battery pack loop is diagnosed by using a simpler current detection method, which is fast in diagnosis and meets the requirement of fast diagnosis before the battery pack provides high-voltage power supply for the whole vehicle.

[0105] Reference will be made to the following Figure 5 The vehicle 3 of the embodiments of the present application is described.

[0106] As Figure 5 shown, the vehicle 3 of the embodiments of the present application comprises the fault diagnosis device 2 of the above embodiments.

[0107] According to the vehicle 3 of the embodiments of the present application, when the vehicle is powered on and there is no fault of the battery pack loop in the last power-on period, the first current value flowing through the negative electrode contactor is detected, the heating contactor in the battery pack loop is diagnosed for fault according to the first current value, when the heating contactor has no fault, the other paths of the battery pack loop are diagnosed for fault, the first current value is detected by controlling the on-off of the related devices such as the heating contactor in the battery pack loop, data support is provided for fault positioning of the battery pack loop, which facilitates later fault troubleshooting, does not need additional high-voltage sampling to detect the whole-pack voltage of the battery pack, the circuit structure is simple, and the battery pack loop is diagnosed by using a simpler current detection method, which is fast in diagnosis and meets the requirement of fast diagnosis before the battery pack provides high-voltage power supply for the whole vehicle.

[0108] In the description of the specification, reference to "one embodiment", "some embodiments", "an exemplary embodiment", "an example", "a specific example", or "some examples" means that a particular feature, structure, material, or characteristic being described is included in at least one embodiment or example of the application. The appearances of the phrases "in one embodiment", "in some embodiments", "in an exemplary embodiment", "an example", "a specific example", or "some examples" in various places in the specification are not necessarily referring to the same embodiment or example.

[0109] While embodiments of the application have been shown and described, it is to be understood that the application is not limited to these embodiments. Rather, it is the intention that modifications, changes, substitutions, and variations be made to the embodiments disclosed herein without departing from the spirit and scope of the application, which is defined solely by the claims and their equivalents.

Claims

1. A failure diagnosis method characterized by comprising: A method for a battery pack loop, the battery pack loop comprising: a negative contactor, a heating contactor, the method comprising: controlling the negative contactor to close when the vehicle is powered on and no battery pack loop fault exists in a last power-on cycle; detecting a first current value flowing through the negative contactor; determining whether the first current value is greater than a first current threshold; if yes, determining that a first type of fault exists in the battery pack loop, the first type of fault being determined that the heating contactor in the battery pack loop is faulty and no open circuit fault exists in the battery pack loop, and controlling the negative contactor to open; otherwise, controlling the heating contactor to close and diagnosing a fault of the battery pack loop; detecting a second current value flowing through the heating contactor; determining whether the second current value is less than or equal to a second current threshold; if yes, determining that a connection fault of a battery cell in the battery pack loop and / or a fault of an external connection of the battery pack exists.

2. The failure diagnosis method according to claim 1, characterized by, Further comprising: controlling the heating contactor to open when the second current value is greater than the second current threshold.

3. The failure diagnosis method according to claim 1, characterized by, Determining that the connection fault of the battery cell in the battery pack loop and / or the fault of the external connection of the battery pack exists comprises: obtaining a voltage sampling value of the battery cell; determining that the connection fault of the battery cell exists when the voltage sampling value is out of a preset voltage threshold range; determining that the connection fault of the battery cell and / or the fault of the external connection of the battery pack exists when the voltage sampling value is not out of the preset voltage threshold range.

4. The failure diagnosis method according to claim 1, characterized by, The battery pack loop further comprises: a positive contactor and a heating device, wherein the heating device and the heating contactor constitute a heating loop, and no battery pack loop fault exists in a last power-on cycle, comprising: determining that no battery pack loop fault exists in the last power-on cycle when the negative contactor, the positive contactor and the heating loop are fault-free.

5. A failure diagnosing apparatus characterized by comprising: Comprising: a control module configured to control the negative contactor to close when the vehicle is powered on and it is determined that no battery pack loop fault exists in a last power-on cycle; a detection module configured to detect a first current value flowing through the negative contactor; a diagnosis module configured to diagnose a fault of the battery pack loop according to the first current value, determine whether the first current value is greater than a first current threshold, if yes, determine that a first type of fault exists in the battery pack loop, the first type of fault being determined that the heating contactor in the battery pack loop is faulty and no open circuit fault exists in the battery pack loop, and control the negative contactor to open, otherwise, control the heating contactor to close and diagnose the fault of the battery pack loop; detect a second current value flowing through the heating contactor, determine whether the second current value is less than or equal to a second current threshold, and if yes, determine that a connection fault of a battery cell in the battery pack loop and / or a fault of an external connection of the battery pack exists.

6. A vehicle characterized by comprising: Comprising: the fault diagnosis apparatus of claim 5.

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