Current sensor fault diagnosis

Abstract

A battery power system includes a battery, a sensor suite, and a controller. The sensor suite includes a current sensor, a voltage sensor, and a temperature sensor. The controller is operable to use current signals from the current sensor and voltage signals from the voltage sensor, along with an equivalent circuit model (ECM), to determine an estimated open-circuit voltage of the battery at different points in time. The controller uses the open-circuit voltage and temperature to determine the ECM's state of charge (SOC) of the battery at different points in time via a calibrated SOC map. The controller also calculates a sensor gain value using the ECM-based SOC and the coulomb counting-based SOC (both at different points in time). When the sensor gain value exceeds a predetermined fault threshold, a control action is executed with respect to the battery, including generating a fault notification signal indicating a fault in the current sensor.

Description

Technical Field

[0001] introduction

[0002] The present disclosure relates to alternative approaches for faults in current sensors (e.g., of a battery power system). Mobile and stationary systems may include one or more electric traction motors whose phase windings are energized by controlled discharge of a propulsion device battery pack. The output torque generated by the energized traction motor(s) may be directed to a driven load, such as driven wheels of a motor vehicle, via a gear set or other intervening power transfer mechanism. Background Art

[0003] A propulsion battery pack consists of an application-specific number and arrangement of electrochemical battery cells. Electronic cell sensing boards (CSBs) are typically connected to the electrodes of a cell or group of cells, where these CSBs collectively measure cell and / or pack-level temperature, voltage, and current. The CSBs then report the measured battery parameters to a resident battery controller, either via physical conductors or using wireless communication. The battery controller, in turn, regulates the ongoing operation and thermal management of the battery pack and associated power electronics.

[0004] Certain measured or derived battery parameters rely on accurate battery pack current measurement, including state of charge (SOC), state of health (SOH), and internal resistance. In a typical propulsion battery pack, the battery pack current delivered to the connected load is measured by a corresponding current sensor circuit, where the battery current is often determined based on the voltage drop across a fixed shunt resistor. When the shunt resistor is degraded due to corrosion, age, or damage, the measured current value often has an artificially high amplitude. Degradation or damage to other types of current sensors can also cause similar inaccuracies. A battery pack with a higher or lower amplitude current reading will appear to be charging or discharging at a specific rate, where the actual rate is higher or lower. Simultaneously, battery resistance estimates will appear larger or smaller than their actual values, causing the resident battery controller to register erroneous negative results when running certain cell fault diagnostic algorithms. Summary of the Invention

[0005] The hardware and software solutions described herein enable detection of current sensor failures in current sensors. Because such failures in assembled and operating battery packs are currently incapable of accurately detecting them, the current state of the art lacks a reliable way to mitigate current sensor failures. In contrast, the method detailed below extends the use of a faulty current sensor through logic adjustments when appropriate. This enables the onboard controller to compensate for measurement errors without triggering intervening maintenance actions, or by alerting the operator whenever sensor errors exceed a threshold.

[0006] One aspect of the present disclosure includes a battery power system having a battery, a sensor assembly, and an electronic controller. The sensor assembly contemplated herein includes a current sensor, a voltage sensor, and a temperature sensor, each operable to output a current signal indicative of a measured battery pack current of the battery, a voltage signal indicative of a measured voltage of the battery, and a temperature signal indicative of a measured temperature of the battery, respectively. In some embodiments, the current sensor may include a fixed shunt resistor of the type generally described above, with the present teachings also being useful for diagnosing other types of current sensors.

[0007] The controller in this exemplary embodiment is in communication with the sensor suite and is configured to determine the estimated open circuit voltage of the battery at different points in time. This occurs using current signals, voltage signals, and an equivalent circuit model (ECM). The controller is configured to use the estimated OCV and measured temperature signals to determine the state of charge (SOC) of the battery at different points in time via a calibrated SOC map. ECM The controller is also configured to use the ECM-based SOC (SOC ECM ) to calculate the sensor gain value. When the sensor gain value exceeds a predetermined fault threshold, the controller ultimately performs a control action, wherein the control action may include generating a fault notification code indicating a fault of the current sensor. The battery state of charge (SOC ECM ) may be determined via the controller as a function of the estimated OCV and the measured battery temperature ( f ), such that:

[0008]

[0009] where OCV is the estimated OCV, and T represents the measured battery temperature.

[0010] In some embodiments, the control action includes selectively adjusting the measured battery current based on the sensor gain value. For example, the controller can be configured to selectively adjust the measured battery current based on the sensor gain value to generate a corrected current value (I) using the following equation, for example, when the sensor gain value is less than or greater than a service threshold. COR ):

[0011]

[0012] in I M is the measured battery pack current, and G is the sensor gain value. For simplicity, the different time points may include at least a first time point and a second time point, wherein the controller is configured to calculate the sensor gain value as:

[0013]

[0014] in is the difference between the corresponding coulomb counting-based SOC values ​​at the first time point and the second time point, and is the corresponding ECM-based SOC of the battery at the first time point and the second time point (SOC ECM ) between the two.

[0015] In some embodiments, the controller may request maintenance actions based on the sensor gain value. The controller may also be configured to use the battery's ECM-based state of charge (SOC ECM ) and SOC value based on coulomb counting (SOC CC ) to calculate the sensor gain value.

[0016] Also disclosed herein is a method for diagnosing a current sensor fault in a battery power system. An exemplary embodiment of the method includes communicating a current signal indicating a measured current of a battery, a voltage signal indicating a measured voltage of the battery, and a temperature signal indicating a measured temperature of the battery via a current sensor, a voltage sensor, and a temperature sensor, respectively. As described above, the current sensor may optionally include a shunt resistor. The method includes determining an estimated open-circuit voltage of the battery at different points in time using the current signal, the voltage signal, and an ECM; and determining an ECM-based state of charge of the battery at different points in time using the estimated open-circuit voltage and the measured temperature via a calibrated SOC map.

[0017] Additionally, the method in this embodiment includes: using the SOC based on the ECM and the SOC based on the coulomb count (SOC CCThe processor of the battery power system further performs a control action on the battery based on the sensor gain value, wherein the control action includes generating a fault notification signal indicating a fault of the current sensor.

[0018] Also disclosed herein is a motor vehicle having: road wheels; and an electrified powertrain system operable to output drive torque to the motor vehicle, i.e., to propel the motor vehicle. The electrified powertrain system includes a propulsion device battery pack, an electric traction motor connected to the propulsion device battery pack, a sensor kit, and a controller. The electrified powertrain system is operable to generate drive torque when energized by the discharge of the propulsion device battery pack, for example, via a power inverter module when the motor is a multi-phase device. The sensor kit includes the current sensor, voltage sensor, and temperature sensor described above. The vehicle controller communicates with the sensor kit and is configured to diagnose the performance of the current sensor using the method of the present disclosure.

[0019] The present invention also provides the following technical solutions:

[0020] 1. A battery power system comprising:

[0021] Battery;

[0022] a sensor assembly comprising: a current sensor operable to output a current signal indicative of a measured battery pack current of the battery; a voltage sensor operable to output a voltage signal indicative of a measured voltage of the battery; and a temperature sensor operable to output a temperature signal indicative of a measured temperature of the battery; and

[0023] a controller in communication with the sensor suite and configured to:

[0024] determining an estimated open circuit voltage of the battery at different points in time using the current signal, the voltage signal, and an equivalent circuit model (ECM);

[0025] determining an ECM-based state of charge of the battery at the different points in time via a calibrated SOC map using the estimated open circuit voltage and the measured temperature;

[0026] calculating a sensor gain value using the ECM-based state of charge (SOC) of the battery at the different time points and the coulomb counting-based SOC at the different time points; and

[0027] When the sensor gain value exceeds a predetermined gain fault threshold, a control action is performed with respect to the battery, including generating a fault notification signal indicating a fault of the current sensor.

[0028] 2. The battery power system of claim 1 , wherein the controller is configured to determine the ECM-based SOC of the battery as a function of the estimated open circuit voltage and the measured temperature of the battery such that:

[0029]

[0030] in, OCV est is the estimated open circuit voltage, and T is the measured temperature.

[0031] 3. The battery power system according to technical solution 1, wherein the battery comprises a propulsion device battery pack for a motor vehicle.

[0032] 4. The battery power system according to technical solution 1, wherein the control action includes: selectively adjusting the measured current based on the sensor gain value.

[0033] 5. The battery power system according to claim 4, wherein the controller is configured to selectively generate a correction current value based on the sensor gain value using the following equation:

[0034]

[0035] Among them, I COR is the correction current value, I M is the measured current, and G is the sensor gain value.

[0036] 6. The battery power system according to technical solution 5, wherein the controller is configured to request a maintenance action on the battery based on the sensor gain value.

[0037] 7. The battery power system according to technical solution 1, wherein the controller is configured to calculate the sensor gain value as:

[0038]

[0039] in is the difference between the coulomb counting-based SOC at the different time points, and is the difference between the ECM-based SOC at the different time points.

[0040] 8. The battery power system according to technical solution 1, wherein the controller is configured to:

[0041] Maturation logic is executed to determine whether a time series progression or trajectory of the gain values ​​indicates the fault of the current sensor.

[0042] 9. A method for diagnosing a current sensor fault in a battery power system, the method comprising:

[0043] measuring, via a current sensor, a voltage sensor, and a temperature sensor of a battery within the battery power system, a current signal indicative of a measured current of the battery, a voltage signal indicative of a measured voltage of the battery, and a temperature signal indicative of a measured temperature of the battery;

[0044] determining an estimated open circuit voltage of the battery at different points in time using the current signal, the voltage signal, and an equivalent circuit model (ECM);

[0045] determining an ECM-based state of charge (SOC) of the battery at the different points in time via a calibrated SOC map using the estimated open circuit voltage and the measured temperature;

[0046] calculating a sensor gain value using the ECM-based SOC of the battery at the different time points and the coulomb counting-based SOC of the battery at the different time points; and

[0047] When the sensor gain value exceeds a predetermined gain fault threshold, a control action is performed with respect to the battery via a processor of the battery power system, including generating a fault notification signal indicating a fault of the current sensor.

[0048] 10. The method according to claim 9, further comprising: determining the ECM-based state of charge of the battery as a function of the estimated open circuit voltage and the measured temperature of the battery, such that:

[0049]

[0050] in, OCV est is the estimated open circuit voltage, and T is the measured temperature.

[0051] 11. The method according to technical solution 9, wherein executing the control action includes: selectively adjusting the measured current based on the sensor gain value.

[0052] 12. The method according to technical solution 11 further comprises: when the sensor gain value is less than a predetermined service threshold, generating a correction current value (I COR ):

[0053]

[0054] Among them, I M is the measured current, and G is the sensor gain value.

[0055] 13. The method according to technical solution 12 further includes: requesting maintenance action of the battery based on the sensor gain value via the controller.

[0056] 14. The method according to claim 9, further comprising: calculating the sensor gain value as the following ratio:

[0057]

[0058] in is the difference between the coulomb counting-based SOC at the different time points, and is the difference between the ECM-based SOC at the different time points.

[0059] 15. The method according to technical solution 9 further comprises: executing a maturation logic to determine whether the time series progression or trajectory of the gain value indicates the fault of the current sensor.

[0060] 16. A motor vehicle comprising:

[0061] a set of travel wheels; and

[0062] an electrified powertrain system operable to output drive torque to the road wheels to propel the motor vehicle, the electrified powertrain system comprising:

[0063] Propulsion unit battery pack;

[0064] an electric traction motor connected to the propulsion battery pack and operable to generate the drive torque when energized by discharge of the propulsion battery pack;

[0065] a sensor assembly comprising: a current sensor operable to output a current signal indicative of a measured battery current of the propulsion battery; a voltage sensor operable to output a voltage signal indicative of a measured voltage of the propulsion battery; and a temperature sensor operable to output a temperature signal indicative of a measured temperature of the propulsion battery; and

[0066] a vehicle controller in communication with the sensor suite and configured to:

[0067] determining an estimated open circuit voltage of the propulsion unit battery pack at different points in time using the current signal, the voltage signal, and an equivalent circuit model (ECM);

[0068] determining an ECM-based state of charge (SOC) of the propulsion unit battery pack at the different points in time via a calibrated SOC map using the estimated open circuit voltage and the measured temperature;

[0069] calculating a sensor gain value using the ECM-based state of charge of the propulsion battery pack at the different points in time and the coulomb counting-based SOC of the propulsion battery pack at the different points in time; and

[0070] When the sensor gain value exceeds a predetermined gain fault threshold, a control action is performed with respect to the propulsion unit battery pack, including generating a fault notification signal indicating a fault of the current sensor.

[0071] 17. The motor vehicle of claim 16, wherein the vehicle controller is configured to determine the ECM-based state of charge of the propulsion battery pack as a function of the estimated open circuit voltage and the measured temperature such that:

[0072]

[0073] in, OCV est is the estimated open circuit voltage, and T is the measured temperature.

[0074] 18. The motor vehicle according to claim 16, wherein the control action comprises: generating a correction current value (I COR ), to selectively adjust the measured current based on the sensor gain value:

[0075]

[0076] Among them, IM is the measured current, and G is the sensor gain value.

[0077] 19. The motor vehicle according to claim 18, wherein the vehicle controller is configured to:

[0078] Maturation logic is executed to determine whether a time series progression or trajectory of the gain values ​​indicates the fault of the current sensor.

[0079] 20. The motor vehicle of claim 16, wherein the vehicle controller is configured to use the ECM-based SOC and coulomb-counting-based state of charge of the propulsion battery pack to calculate the sensor gain value as the following ratio:

[0080]

[0081] in is the difference between the coulomb counting-based SOC at the different time points, and is the difference between the ECM-based SOC at the different time points. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Figure 1 is a schematic illustration of a motor vehicle having a propulsion battery pack including current sensors that are diagnosed using the strategies detailed herein.

[0083] Figure 2 is a representative current-voltage performance graph of a nominally healthy current sensor and a faulty current sensor, where current in amperes (A) is plotted on the horizontal axis and voltage in volts (V) is plotted on the vertical axis.

[0084] Figure 3 is a description of the method used to construct an open circuit voltage (OCV) to state of charge (SOC) map for use in Figure 1 Flowchart of a method for use on a motor vehicle.

[0085] Figure 4 Is a description for use Figure 3 Flowchart of a method for detecting current sensor failure using OCV to SOC mapping. DETAILED DESCRIPTION

[0086] The present disclosure is susceptible of embodiments in many different forms. Representative examples of the present disclosure are shown in the accompanying drawings and described in detail herein as non-limiting examples of the disclosed principles. For that purpose, elements and limitations described in the Abstract, Introduction, Summary, and Detailed Description sections but not explicitly recited in the claims should not be incorporated, individually or collectively, into the claims by implication, inference, or otherwise.

[0087] For the purposes of this description, unless expressly disclaimed, the use of the singular includes the plural and vice versa, the words "and" and "or" shall both be conjunctive and non-conjunctive, "any" and "all" shall both mean "any and all," and the words "including," "containing," "comprising," "having," and the like shall mean "including but not limited to." Furthermore, approximate terms such as "about," "almost," "substantially," "generally," "approximately," and the like may be used herein in the sense of "is, approximately, or nearly," or "within 0-5% of," or "within acceptable manufacturing tolerances," or logical combinations thereof.

[0088] Referring to the drawings, wherein like reference numerals refer to like features throughout the several views and from Figure 1 Initially, the battery power system 10 includes an energy storage system 12 having electrochemical batteries 14, such as battery cells, modules, or a number of battery cells or modules assembled into a battery pack suitable for the application. Figure 1 As shown in FIG, the energy storage system 12 is part of an electrified powertrain system 16 of a motor vehicle 18, such as a fully electric vehicle, a hybrid vehicle, or an extended-range electric vehicle (EV), in which the battery 14 serves as a high-voltage propulsion battery pack (B HV In this configuration, the battery 14 can be connected to a traction power inverter module (TPIM) 20 via the positive (+) and negative (-) rails of a direct current (DC) voltage bus 22. As is known in the art, the TPIM 20's on / off state switching control is used to convert the TPIM 20's DC input voltage into a multi-phase / alternating current (AC) output voltage. The AC output voltage energizes an AC voltage bus 24, such as the nominal a, b, and c phases of a representative three-phase configuration of the AC voltage bus 24.

[0089] In a representative configuration of the motor vehicle 18, an AC voltage bus 24 connects the TPIM 20 to the electric traction motor (M E) 25. In particular, the electric traction motor 25 may include a wound stator 25S surrounding a magnetic rotor 25R, with an output member 26 coupled to the rotor 25R and ultimately connected to a set of road wheels 28 disposed on one or more drive axles 29. When the electric traction motor 25 is powered in this configuration by the battery 14 via the TPIM 20, or directly in the DC motor embodiment, the rotor 25R rotates within the stator 25S and thereby generates output torque (arrow T O ) as the driving torque. Embodiments of the electric powertrain system 16 may include an electronic or mechanical differential 30, wherein the differential 30 is rotatably connected to the drive axle 29 as an independently controllable element, for example, when the output torque (arrow T O ) is allocated to the running wheels 28 to propel the motor vehicle 18.

[0090] Used as Figure 1 Other power electronic components that are part of the exemplary electric powertrain system 16 shown in FIG may include an auxiliary power module (APM) 40 connected to the DC voltage bus 22, and an auxiliary battery (B) connected to the APM 40 via an auxiliary voltage bus 41. AUX ) 42. As used herein, "auxiliary" refers to a low voltage level relative to the voltage level of the DC voltage bus 22, where a typical auxiliary voltage level for automotive applications is 12-15 V. By comparison, the DC voltage bus 22 may have a corresponding voltage level of 60-400 V or higher, depending on the application.

[0091] As part of this diagnostic strategy, Figure 1 The battery 14 includes a battery configured to output a set of battery parameters (CC P ) of the sensor suite 31. The sensor suite 31 includes a current sensor 32I, such as a Hall effect sensor. The sensor suite 31 also includes a voltage sensor 32V and a temperature sensor 32T (such as a thermocouple or thermistor). The current sensor 32I (optionally including a shunt resistor (R S ) 34) performance is particularly diagnosed via the controller 50, as hereinafter referred to Figure 2-4 Detailed description. Current sensor 32I is operable to output a current signal (arrow I) indicative of a measured battery current of battery 14, where current sensor 32I may do so based on a voltage drop appearing across optional shunt resistor 34, as is understood in the art. As described above, certain measured or derived battery parameters rely on accurate measurement of battery current, including calculation of the present state of charge (SOC), state of health (SOH), and internal resistance of battery pack 14. Thus, the present strategy enables controller 50 to diagnose a fault in current sensor 32I and respond to such a fault in an appropriate manner depending on the severity of the fault.

[0092] Further with respect to the sensor suite 31, the voltage sensor 32V is operable to output a voltage signal (arrow V) indicative of the measured cell, module, or pack-level voltage of the battery 14. Similarly, the temperature sensor 32T is operable to output a temperature signal (arrow T) indicative of the measured temperature of the battery 14. The sensor suite 31 may include additional sensors not mentioned here. Additionally, although described in singular terms for simplicity of illustration, multiple current sensors 32I, voltage sensors 32V, and temperature sensors 32T may be used in other embodiments, and therefore, unless otherwise specified, references to a singular sensor type apply to embodiments including multiple sensors of the same type.

[0093] In some embodiments, the controller 50 is configured to execute the present strategy on the motor vehicle 18 within its capabilities as a resident vehicle controller. Alternatively, Figure 1 The controller 50 depicted in FIG. 5 has the potential to send raw current, voltage, and temperature data to an off-board server, computer, or processing unit, where the disclosed open circuit voltage estimation is performed at such processing node. Figure 1 The controller 50 may be embodied as one or more processing nodes, some of which may be located on the motor vehicle 18 and others of which may be located off-board. Figure 3 Method 100 and Figure 4 For purposes of method 200 ), the controller 50 is equipped with an application-specific amount of volatile and non-volatile memory (M) 52 and one or more processors (P) 54 (e.g., a microprocessor or central processing unit), as well as other associated hardware and software, such as a digital clock or timer, input / output circuits, buffer circuits, application-specific integrated circuits (ASICs), systems on a chip, electronic circuits, and other necessary hardware as needed to provide the programmed functionality.

[0094] It is within the scope of the present disclosure to communicate with the sensor suite 31 as part of the control action. Figure 1 The controller 50 finally generates an output signal (arrow CC O ) to adjust the battery parameters (CC P ) to respond. This action can be referenced as follows Figure 2-4The controller 50 is operable to determine an estimated open circuit voltage (OCV) of the battery 14 at various points in time using the current signal (arrow I), the voltage signal (arrow V), and the equivalent circuit model (M1) 55. The controller 50 also determines the ECM-based state of charge (SOC) of the battery 14 at various points in time via a calibrated SOC map (M2) 56. ECM ), where the abbreviation "ECM" represents the equivalent circuit model 55. The controller 50 does this using the estimated OCV and the temperature signal (arrow T) described above. The controller 50 then uses the state of charge (SOC ECM ) to calculate the above-mentioned sensor gain value, and thereafter, when the sensor gain value exceeds a predetermined fault threshold, one or more control actions are performed on the battery 14.

[0095] refer to Figure 2 , Figure 60 illustrates Figure 1 Representative current-voltage performance of a nominally "healthy" version and a "faulty" version of current sensor 32I. The performance of the healthy current sensor 32I is represented by trace 62, while the performance of the faulty current sensor 32I is represented by trace 64. Current in amperes (A) is plotted on the horizontal axis (x). Voltage in volts (V) is plotted on the vertical axis (y1), with estimated OCV also in volts plotted on the vertical axis (y2). Comparison of the two traces 62 and 64 (sharing the same intercept point (b), in this case 373.61 V) shows that the corresponding slopes are different. Figure 2 In the diagram of , for example, and using the slope-intercept form , trace 62 can be expressed as , and trace 64 can be expressed as It will be appreciated that the two traces 62 and 64 intercept the y2 axis at the same estimated OCV, but at different slopes or gradients. Therefore, with this knowledge, when calculating the digital gain value and in the diagnostic Figure 1 The performance of the current sensor 32I is determined when using this digital gain value and the present diagnostic strategy is continued.

[0096] More specifically, the current gain failure of the current sensor 32I affects the SOC calculation performed using the coulomb counting method, rather than the calculation performed using the equivalent circuit model. In the latter case, the sensor gain failure directly affects the resistance estimate, i.e., the VI curve (such as Figure 2The slope of the representative traces 62 and 64) is determined without affecting the OCV estimate or the y2 intercept. As will be appreciated by one skilled in the art, coulomb counting proceeds according to the validated equation:

[0097]

[0098] Where SOC0 is the initial SOC, I is the current, and Cap nom is the battery capacity in ampere hours. In contrast, the ECM equation can be expressed as follows:

[0099]

[0100] Therefore, the present strategy involves: transforming the SOC from the equivalent circuit model (i.e., SOC ECM ) is compared with the SOC derived from coulomb counting (i.e., SOC CC ) to detect sensor gain failure. Figure 3 and Figure 4 An exemplary implementation of this strategy is described below.

[0101] Figure 3 Depicts a flow chart for implementing a method 100 that allows for offline execution Figure 1 The controller 50 constructs an estimated OCV (OCV est ), the current temperature of the battery 14 as measured by the temperature sensor 32T, and the above-mentioned state of charge based on coulomb counting (ie, SOC CC ) mapping.

[0102] Starting from block B102, the current sensor 32I measures and outputs a current signal (arrow I), which indicates Figure 1 The measured battery current of the battery 14, whether for a particular cell or a collection of such cells (possibly including the entire battery 14), is measured. Block B104 performs a similar process, but with the voltage sensor 32V outputting the voltage sensor (arrow V). Once the measured battery current and voltage have been communicated to the controller 50, the method 100 proceeds to block B106.

[0103] Block B106 entails processing the measured values ​​from blocks B102 and B104 through an equivalent circuit model, thereby estimating the open circuit voltage of the battery 14 or its constituent battery cells. The estimated open circuit voltage (denoted herein as OCV est ) is then fed into block B110.

[0104] Block B106 may be implemented in various ways. For example, the controller 50 may use what is referred to herein as a "segmented" approach to help determine the estimated open circuit voltage, or OCV.est As is known in the art, the outputs of the current sensor 32I and the voltage sensor 32V from the respective blocks B102 and B104 are raw data that, when combined, provide a so-called VI profile. The controller 50 can be configured to identify distinct line segments by filtering out extreme values ​​in the VI profile, as is known in the art.

[0105] For each segment, the controller 50 may remove the where "significantly" is a predetermined variation that may be application specific. The remainder of a given segment may be retained if the segment meets predetermined criteria (such as a predetermined current spread, e.g., > 60 A), if the segment spans 0 A, and if for the entire segment are all less than a predetermined threshold (such as 100 A / s consistent with the illustrative 80 A current spreading example).

[0106] Therefore, the result of executing block B106 will be presented as Figure 2 , but there are more segments, where each VI segment corresponds to a different OCV est Additionally, the controller 50 may calculate the gradient between each pair of points along each VI line segment, where each point 61 is Figure 2 . The controller 50 may then determine the median gradient and remove pairs of points that have gradients that exceed the median gradient by a predetermined amount (e.g., 50%). Thus, in this example, the controller 50 retains the longest run of pairs of points that have gradients that differ from the median gradient by less than 50%, and calculates the classical The slope (m) and y-intercept (b) of the formula can be used as the resistance and OCV respectively. est is recorded or sent outside the vehicle. Other methods can be used as an alternative to the segmentation method. For example, ECM can be used with recursive least squares, pseudo-inverse methods, etc., as known in the art.

[0107] Block B107 includes performing coulomb counting to determine the current SOC of the battery 14, wherein the coulomb counting method for SOC derivation is well established in the art and is mathematically described above. CC ) is then fed into block B110.

[0108] At block B108, Figure 1 The temperature sensor 32T reads the battery temperature and communicates it to the controller 50. The method 100 then proceeds to block B110.

[0109] Figure 3Block B110 includes determining the OCV from the VI segment intercept point for a given temperature as determined at block B108. est , as described above. For example, during training, in order to build a relevant map, at a given moment, the OCV est and temperature are mapped to specific SOC CC During the test, the temperature and OCV est This map is used as input to determine a specific SOC estimate. The result of block B110 is OCV est SOC vs. Temperature CC , which may then be recorded in the memory 52 of the controller 50 as map (M2) 56. That is, during training of the controller 50, a different set of OCV, temperature, and SOC data points are generated using the segmentation method described above or a suitable alternative such as RLS.

[0110] Fitting methods can be used to construct temperature, OCV est and SOC CC For example, polynomial fitting, interpolation, machine learning using Gaussian-based regression methods, or using triaxial curves, to name a few. est The SOC is extracted by the controller 50 as a percentage between 0% and 100% depending on the battery / cell temperature (eg, 0° to 40°C). ECM , and thereafter used in the method 200 described below. The generated map can be updated with data collected over time along with battery aging information / data. Figure 4 An exemplary embodiment of method 100 is described.

[0111] Now refer to Figure 4 , the controller 50 is configured to detect Figure 1 The gain failures of the current sensor 32I shown in FIG. 1 are caused by the OCV of the method 100. est Starting from blocks B201A and B201B, the controller 50 loads the current and voltage data at different time points t1 and t2, respectively, where time t2 is after time t1, for example, a few seconds later. Then, the method 200 proceeds to blocks B203A and B203B.

[0112] Blocks B203A and B203B need to estimate the open circuit voltage (OCV) of the battery 14 using the values ​​provided from blocks B201A and B201B. est ). This occurs as described above in block B106. Method 200 then proceeds to blocks B210A and B210B.

[0113] At blocks B208A and B208B, the temperature sensor(s) 32T are used to measure the temperature at time points t1 (block B208A) and t2 (block B208B). Figure 1 The battery temperature (arrow T) is measured. The measured values ​​are provided to blocks B210A and B210B, respectively.

[0114] At blocks B210A and B210B, method 200 includes processing the temperatures measured at t1 and t2 from respective blocks B208A and 208B, and the OCV at the same time points from respective blocks B203A and 203B. est Method 200 then proceeds to blocks B211A and B211B.

[0115] Blocks B211A and B211B need to be used for time points t1 and t2 Figure 3 The two SOCs at time points t1 and t2 are determined by mapping the state of charge of block B110. ECM The value is then fed into block B214.

[0116] At blocks B213A and B213B, again for time points t1 and t2, the controller 50 loads the state of charge (ie, SOC) based on coulomb counting. CC ), and then proceed to block B214.

[0117] exist Figure 4 At block B214 , method 200 continues by calculating a sensor gain value (G), for example, using the following function:

[0118]

[0119] in is the difference between the corresponding coulomb counting-based SOC values ​​at the first time point t1 and the second time point t2, and is the corresponding state of charge (SOC) of the battery 14 at these two points in time. ECM ). The method 200 then proceeds to block B216.

[0120] Block B216 acts as maturity logic (ML) before executing subsequent control actions. Specifically, block B216 can be used to detect gain failures over the duration of a trip, rather than at a single / discrete point in time. Maturity criteria can be used to confirm that the problem persists over multiple trips. For example, controller 50 may collect sensor gain values ​​(G) for a predetermined number (Y) of trips before proceeding to block B218.

[0121] At block B218, the controller 50 next compares the sensor gain (G) to a threshold to determine if a gain fault exists. In some embodiments, block B218 may entail comparing the gain value (G) to a calibrated threshold (e.g., 20-30%). Alternatively, based on the proven logic described above, the controller 50 may evaluate whether the gain (G) exceeds the threshold for X out of Y trips (e.g., 7 out of 10 trips), or whether the time series progression or trajectory of the gain indicates a gain fault. Method 200 then proceeds to block B220.

[0122] The method 200 is completed at block B220, where the controller 50 performs a control action with respect to the battery 14 when the sensor gain value (G) exceeds a predetermined fault threshold. Block B220 may include generating a fault notification indicating a fault in the shunt resistor and / or selectively adjusting the measured battery pack current based on the sensor gain value (G). In a particular embodiment, the controller 50 may be configured to selectively adjust the measured battery pack current based on the sensor gain value (G) to generate a correction current value (I) when the sensor gain value (G) is less than a predetermined service threshold. COR ). This can be done using the equation Occurrence, where I M is the measured battery pack current. The controller 50 may also be configured to request a maintenance action on the battery 14 when the sensor gain value (G) exceeds a service threshold.

[0123] The detailed description and accompanying drawings or figures support and describe the present teachings, but the scope of the present teachings is limited only by the claims. Although some of the best modes and other embodiments for implementing the present teachings have been described in detail, there are various alternative designs and embodiments for practicing the present teachings as defined in the appended claims. In addition, the present disclosure expressly includes combinations and subcombinations of the elements and features presented above and below.

Claims

1. A battery power system comprising: Battery; a sensor assembly comprising: a current sensor operable to output a current signal indicative of a measured battery pack current of the battery; a voltage sensor operable to output a voltage signal indicative of a measured voltage of the battery; and a temperature sensor operable to output a temperature signal indicative of a measured temperature of the battery; and a controller in communication with the sensor suite and configured to: determining an estimated open circuit voltage of the battery at different points in time using the current signal, the voltage signal, and an equivalent circuit model (ECM); determining an ECM-based state of charge of the battery at the different points in time via a calibrated SOC map using the estimated open circuit voltage and the measured temperature; calculating a sensor gain value using the ECM-based state of charge (SOC) of the battery at the different time points and the coulomb counting-based SOC at the different time points; and When the sensor gain value exceeds a predetermined gain fault threshold, a control action is performed with respect to the battery, including generating a fault notification signal indicating a fault of the current sensor.

2. The battery power system according to claim 1, wherein: The controller is configured to determine the ECM-based SOC of the battery as a function of the estimated open circuit voltage and the measured temperature of the battery such that: in, OCV est is the estimated open circuit voltage, and T is the measured temperature.

3. The battery power system according to claim 1, wherein: The battery comprises a propulsion battery pack for a motor vehicle.

4. The battery power system according to claim 1, wherein: The control action includes selectively adjusting the measured current based on the sensor gain value.

5. The battery power system according to claim 4, wherein: The controller is configured to selectively generate a correction current value based on the sensor gain value using the following equation: Among them, I COR is the correction current value, I M is the measured current, and G is the sensor gain value.

6. The battery power system according to claim 5, wherein: The controller is configured to request a maintenance action on the battery based on the sensor gain value.

7. The battery power system according to claim 1, wherein: The controller is configured to calculate the sensor gain value as: in is the difference between the coulomb counting-based SOC at the different time points, and is the difference between the ECM-based SOC at the different time points.

8. The battery power system according to claim 1, wherein: The controller is configured to: Maturation logic is executed to determine whether a time series progression or trajectory of the gain values ​​indicates the fault of the current sensor.

9. A method for diagnosing a current sensor fault in a battery power system, the method comprising: measuring, via a current sensor, a voltage sensor, and a temperature sensor of a battery within the battery power system, a current signal indicative of a measured current of the battery, a voltage signal indicative of a measured voltage of the battery, and a temperature signal indicative of a measured temperature of the battery; determining an estimated open circuit voltage of the battery at different points in time using the current signal, the voltage signal, and an equivalent circuit model (ECM); determining an ECM-based state of charge (SOC) of the battery at the different points in time via a calibrated SOC map using the estimated open circuit voltage and the measured temperature; calculating a sensor gain value using the ECM-based SOC of the battery at the different time points and the coulomb counting-based SOC of the battery at the different time points; as well as When the sensor gain value exceeds a predetermined gain fault threshold, a control action is performed with respect to the battery via a processor of the battery power system, including generating a fault notification signal indicating a fault of the current sensor.

10. The method according to claim 9, further comprising: The ECM-based state of charge of the battery is determined as a function of the estimated open circuit voltage and the measured temperature of the battery such that: in, OCV est is the estimated open circuit voltage, and T is the measured temperature.

11. The method according to claim 9, wherein Performing the control action includes selectively adjusting the measured current based on the sensor gain value.

12. The method according to claim 11, further comprising: When the sensor gain value is less than a predetermined service threshold, the correction current value (I COR ): Among them, I M is the measured current, and G is the sensor gain value.

13. The method according to claim 12, further comprising: A maintenance action is requested, via a controller, for the battery based on the sensor gain value.

14. The method of claim 9, further comprising: The sensor gain value is calculated as the following ratio: in is the difference between the coulomb counting-based SOC at the different time points, and is the difference between the ECM-based SOC at the different time points.

15. The method of claim 9, further comprising: Maturation logic is executed to determine whether a time series progression or trajectory of the gain values ​​indicates the fault of the current sensor.

16. A motor vehicle comprising: A set of traveling wheels; as well as an electrified powertrain system operable to output drive torque to the road wheels to propel the motor vehicle, the electrified powertrain system comprising: Propulsion unit battery pack; an electric traction motor connected to the propulsion battery pack and operable to generate the drive torque when energized by discharge of the propulsion battery pack; a sensor assembly comprising: a current sensor operable to output a current signal indicative of a measured battery current of the propulsion battery; a voltage sensor operable to output a voltage signal indicative of a measured voltage of the propulsion battery; and a temperature sensor operable to output a temperature signal indicative of a measured temperature of the propulsion battery; and a vehicle controller in communication with the sensor suite and configured to: determining an estimated open circuit voltage of the propulsion unit battery pack at different points in time using the current signal, the voltage signal, and an equivalent circuit model (ECM); determining an ECM-based state of charge (SOC) of the propulsion unit battery pack at the different points in time via a calibrated SOC map using the estimated open circuit voltage and the measured temperature; calculating a sensor gain value using the ECM-based state of charge of the propulsion battery pack at the different points in time and the coulomb counting-based SOC of the propulsion battery pack at the different points in time; and When the sensor gain value exceeds a predetermined gain fault threshold, a control action is performed with respect to the propulsion unit battery pack, including generating a fault notification signal indicating a fault of the current sensor.

17. A motor vehicle according to claim 16, wherein: The vehicle controller is configured to determine the ECM-based state of charge of the propulsion battery pack as a function of the estimated open circuit voltage and the measured temperature such that: in, OCV est is the estimated open circuit voltage, and T is the measured temperature.

18. The motor vehicle of claim 16, wherein: The control action includes generating a correction current value (I COR ), to selectively adjust the measured current based on the sensor gain value: Among them, I M is the measured current, and G is the sensor gain value.

19. A motor vehicle according to claim 18, wherein: The vehicle controller is configured to: Maturation logic is executed to determine whether a time series progression or trajectory of the gain values ​​indicates the fault of the current sensor.

20. The motor vehicle of claim 16, wherein: The vehicle controller is configured to use the ECM-based SOC and coulomb-counting-based state of charge of the propulsion battery pack to calculate the sensor gain value as the following ratio: in is the difference between the coulomb counting-based SOC at the different time points, and is the difference between the ECM-based SOC at the different time points.

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