System and method for battery cell degradation detection

Abstract

The invention provides a system and a method for battery cell degradation detection. Methods and systems are provided for a high voltage multi-array battery for a plug-in vehicle. In one example, a method may include monitoring that a rate of change of a difference in maximum cell voltage deviations of at least one cell array of a high voltage multi-array battery exceeds a predetermined threshold. In response to the rate of change exceeding a predetermined threshold, plug-in charging is aborted and a diagnostic fault code (DTC) is recorded in a memory of the vehicle.

Description

Technical Field

[0001] The present description generally relates to methods and systems for detecting degradation of a high voltage multi-array battery during plug-in charging of the high voltage multi-array battery. Background Art

[0002] Traction batteries, such as lithium (Li) ion batteries, are integral to hybrid electric vehicles, plug-in hybrid electric vehicles, and battery electric vehicles (HEV, PHEV, and BEV, respectively). Batteries are typically composed of one or more arrays having a plurality of individual battery cells, wherein the battery cells are designed to operate for a specified time frame (typically multiple years) or a specified number of miles of use. The traction battery provides power for vehicle propulsion and accessory features. During operation, the traction battery may be charged or discharged based on operating conditions. It is desirable to detect any premature degradation or loss of function of the battery cells in the battery pack to provide an alert to the user so that the battery can be repaired before potential further degradation or loss of function. Degradation or loss of function may be caused by a variety of mechanisms, including high resistance internal short circuits, low resistance internal short circuits, and lithium plating on components within the battery cell. Another mechanism of excessive capacity loss includes accelerated chemical changes within the battery cell. Detection of battery cell degradation by conventional means is not reliable, and the nature of battery cell degradation events and the relatively low degradation rates present challenges for unambiguous detection.

[0003] Attempts to address battery cell degradation include monitoring the rate of change of voltage at the battery cell level. Chikkannanavar et al. show an exemplary method in US9840161. Therein, a battery management system includes a controller configured to output an error signal in response to the rate of change of voltage during discharge of the battery cell exceeding a first threshold for more than a predetermined number of times within a predefined duration. In addition, Chikkannanavar et al. show a vehicle battery management system, which includes a controller configured to output an error signal in response to the rate of change of voltage of the battery cell exceeding a first threshold when the battery cell is partially discharged during a recharging event, or in response to the number of cases where the rate of change exceeds a second threshold that is less than the first threshold exceeds a counting threshold. Summary of the invention

[0004] However, the inventors herein have recognized potential problems with such systems. As an example, a system that monitors battery cell degradation at the battery cell level may be computationally intensive for a processor that performs calculations to identify changes in the voltage of a battery cell relative to another parameter such as time, state of charge, etc. For example, if the calculation is done at the battery cell level for each battery cell, the calculation of a battery pack with 192 series cells will include 192 calculations. In addition to being computationally intensive, such a calculation method may require an excessively long duration, for example, as the battery cells of the battery pack further degrade. Alternatively, performing calculations to detect changes in the voltage of battery cells at the array level or battery level may make it challenging to capture individual battery cell degradation. For example, a drop in the battery cell voltage of a single battery cell of an array or battery may not necessarily be identified in a 400V to 800V battery. In addition, due to the size and power of the high voltage battery, the calculation method for calibrating the high voltage battery (e.g., 400V-800V) may be challenging. Therefore, there is a need for a method for detecting abnormal changes in voltage of battery cells of a multi-cell battery pack that reduces the number of calculations and reduces the time taken to detect abnormal changes while maintaining or improving the accuracy of degradation detection at the battery cell level.

[0005] In one example, the above problem can be solved by a method during plug-in charging of a high voltage multi-array battery of a vehicle, the method comprising: in response to the rate of change of the difference of the maximum cell voltage deviation of at least one cell array of the high voltage multi-array battery exceeding a predetermined threshold, suspending plug-in charging and recording a diagnostic trouble code (DTC) in a memory of the vehicle. In this way, the time between a cell degradation or loss of function event and the detection of the event can be reduced compared to conventional methods, which can further reduce the time between the event and the response thereto.

[0006] As an example, the rate of change of the difference of the maximum cell voltage deviation of the cell array is the difference between the instantaneous maximum cell voltage deviation of the cell array and the historical moving average of the maximum cell voltage deviation. The instantaneous maximum cell voltage deviation can be calculated by identifying the instantaneous voltage of each battery cell of the array (e.g., each battery cell is identified at the same time), identifying the first battery cell and the second battery cell of the array having the maximum voltage and the minimum voltage of the instantaneous voltage, respectively, and calculating the average voltage of the array excluding the voltages of the first battery cell and the second battery cell. The historical moving average over a period of time before the time when the instantaneous voltage is collected can be calculated in a manner similar to the calculation of the instantaneous maximum cell voltage deviation. The predetermined threshold can be a non-zero positive value of the rate of change of the difference of the maximum cell voltage deviation of the cell array, equal to or above the non-zero positive value, degradation of one or more battery cells of the array may occur. For example, the value of the rate of change may be greater than the rate of change at which the battery cell is configured to charge, so that when the rate of change of the difference in the maximum cell voltage deviation of the cell array exceeds a predetermined threshold, this may indicate that the voltage of one or more battery cells is changing faster or slower than expected, which may indicate degradation or loss of function of the corresponding battery cell. In addition, a battery current rate of change criterion may be introduced so that the rate of change of the maximum cell voltage deviation detection may be more accurate.

[0007] By calculating the instantaneous maximum cell voltage deviation and the historical moving average of the maximum cell voltage deviation for an array of battery cells rather than for each battery cell of the array, the method described herein reduces the computational requirements on the processor, increases the computational speed, and reduces the time to detect degradation of one or more battery cells. The method described herein includes calculating the rate of change of the difference of the maximum cell voltage deviation for each array, rather than calculating the derivative of the cell voltage of each battery cell of an array of high-voltage multi-array batteries. By detecting such changes in cell voltage during charging of a high-voltage multi-array battery, cell degradation and / or cell function loss can be anticipated, and the operation of the high-voltage multi-array battery (e.g., plug-in charging operation) can be adjusted to reduce further degradation of the battery cells.

[0008] It should be understood that the above summary is provided to introduce a series of concepts further described in the detailed description in a simplified form. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is uniquely defined by the claims following the detailed description. Furthermore, the claimed subject matter is not limited to embodiments that address any disadvantages mentioned above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A schematic diagram of a plug-in vehicle with a high voltage multi-array battery is shown.

[0010] Figure 2 A schematic diagram of a high voltage multi-array battery is shown.

[0011] Figure 3 A graph showing the voltage of a battery cell of a high voltage multi-array battery as a function of time.

[0012] Figure 4 A flow chart showing a method for plug-in charging of a high voltage multi-array battery is shown.

[0013] Figure 5 Shown according to Figure 4 A timing diagram of the method for operation of a high voltage multi-array battery. DETAILED DESCRIPTION

[0014] The following description relates to systems and methods for detecting degradation of battery cells of a high voltage multi-array battery by monitoring the rate of change of a difference in maximum cell voltage deviation of at least one cell array of the high voltage multi-array battery. The high voltage multi-array battery may be integrated in a plug-in vehicle and used to power drive and auxiliary functions of the plug-in vehicle, an example of which is shown in FIG. Figure 1 The high voltage multi-array battery and therefore its battery cells (also referred to herein as "battery cells") can be charged (e.g., increase the cell state of charge) via a plug-in charging operation. Such as can be Figure 1 An exemplary schematic diagram of a high voltage multi-array battery used in a plug-in vehicle is shown in Figure 2 The high voltage multi-array battery includes a plurality of battery cells arranged in a plurality of arrays, and a sensor module and a battery energy control module (BECM) for monitoring the voltage of each battery cell. Figure 3 A graph showing changes in cell voltages of a plurality of battery cells of an array over time is shown. An embodiment of a method for detecting degradation of a battery cell of a high voltage multi-array battery by monitoring the rate of change of a difference in maximum cell voltage deviations of at least one cell array of the high voltage multi-array battery is provided in Figure 4 The method described herein includes suspending plug-in charging and recording a diagnostic trouble code (DTC) in response to a rate of change of a difference in maximum cell voltage deviation of at least one cell array exceeding a predetermined threshold rate of change. Figure 5 The timing diagram shown illustrates operation of a high voltage multi-array battery in a plug-in vehicle, including terminating a plug-in charging operation in response to a rate of change of a difference in maximum cell voltage deviations of at least one cell array exceeding a predetermined threshold rate of change.

[0015] Figure 1A schematic diagram of a plug-in vehicle 100 is depicted. Plug-in vehicle 100 may be a plug-in electric vehicle, wherein propulsion of plug-in vehicle 100 is powered by one or more electric motors using electricity stored by a traction battery. In other embodiments, plug-in vehicle 100 may be a plug-in hybrid electric vehicle, including an engine as a source of rotational power in addition to one or more electric motors using electricity stored by a traction battery. It should be understood that plug-in vehicle 100 may be a plug-in hybrid electric vehicle. Figure 1 1 is shown for illustrative purposes and is a non-limiting example of how a plug-in vehicle may be configured. Other examples include the components of the plug-in vehicle 100 described below and Figure 1 Various arrangements and positioning of additional components are not shown for the sake of brevity.

[0016] The drive train 106 of the plug-in vehicle 100 may include a transmission 108 (e.g., a gearbox, a gear train, etc.) coupled to one or more of the front axle 104 and the rear axle 112 of the plug-in vehicle 100. Each of the front axle 104 and the rear axle 112 may have a pair of wheels 102 positioned thereon and coupled thereto. The transmission 108 may be mechanically coupled to a final drive 110 of the drive train 106, which may be, for example, a differential or any other suitable gear device. The transmission 108 and the final drive 110 may together transfer speed and torque from a rotational source to the pair of wheels 102 coupled to each of the front axle 104 and the rear axle 112 to propel the plug-in vehicle 100. The present configuration includes at least two transmission input shafts, including a first transmission input shaft 160 coupling the first motor 114 and the transmission 108, and a second transmission input shaft 158 ​​coupling the second motor 116 and the transmission 108. The first motor 114 and the second motor 116 may be collectively referred to herein as motors. In other embodiments, the plug-in vehicle 100 may include more or less than two motors without departing from the scope of the present disclosure. In addition, the transmission 108 may be mechanically coupled to the final drive 110 via an output gear set 144. In off-highway vehicle applications, a drive shaft (not shown) may be included to mechanically couple the output of the transmission to the input of an axle (such as the front axle 104 and / or the rear axle 112).

[0017] When configured as a plug-in electric vehicle, the rotation source of the plug-in vehicle 100 can be a first motor 114 and a second motor 116. In some examples, and as described herein, the first motor 114 and the second motor 116 can be motor / generators having the ability to convert electrical energy into mechanical energy (or vice versa). Therefore, the motors may also be referred to as motors and / or generators hereinafter. The motors may be similarly configured, such as having similar operating speed and torque ranges, and are thereby referred to as symmetrical, or may have different speed and torque outputs, thereby referred to as asymmetrical. The first motor 114 and the second motor 116 may be electrically coupled to a traction battery, such as a high voltage multi-array (HVMA) battery 120 of the plug-in vehicle 100, to draw power from the HVMA battery 120 and provide electrical energy to be stored at the HVMA battery 120. For example, the HVMA battery 120 may be electrically coupled to one or more power electronics modules 148. The power electronics module 148 may also be electrically coupled to the first and second electric machines 114 and 116 and provide the ability to bi-directionally transfer energy between the HVMA battery 120 and the electric machines.

[0018] The HVMA battery 120 can have a capacity of 400V to 800V and include multiple battery arrays, each battery array including at least two battery cells. One or more contactors 142 can isolate the HVMA battery 120 from other components when open, and connect the HVMA battery 120 to other components when closed. In some embodiments, when the contactor 142 is closed, the HVMA battery 120 can provide a high-voltage direct current (DC) output to the first motor 114 and / or the second motor 116. For example, the HVMA battery 120 can provide a DC voltage, and the motor can function with three-phase alternating current (AC) operation. The power electronics module 148 can convert the DC voltage into a three-phase AC current to operate the motor. In regenerative mode, the power electronics module 148 can convert the three-phase AC current from the motor acting as a generator into a DC voltage compatible with the HVMA battery 120. In addition to providing energy for propulsion, the HVMA battery 120 can also provide energy for other vehicle electrical systems, such as auxiliary devices of the plug-in vehicle 100 (e.g., electric heaters, entertainment devices, etc.). About Figure 2 Further details regarding high voltage multi-array batteries are described.

[0019] When configured as a plug-in hybrid electric vehicle, the rotation source of the plug-in vehicle 100 can be a first motor 114, a second motor 116, and an engine 118, such as an internal combustion engine. The engine 118 can be coupled to the transmission 108 to provide rotational energy thereto. For example, the plug-in vehicle 100 may also include a third transmission input shaft 146 coupling the engine 118 and the transmission 108. When the engine 118 is turned on or off, the first motor 114 and the second motor 116 can provide forward and reverse torque capabilities. The operation of the engine 118 to provide power for vehicle propulsion can be supplemented by the first motor 114 and the second motor 116.

[0020] The HVMA battery 120 of the plug-in vehicle 100 can be recharged by an external power source 136. The external power source 136 can be a connection to an electrical outlet, or can be a power distribution network or a power grid such as provided by an electric utility company. The external power source 136 can be electrically connected to a charger or other electric vehicle supply equipment (EVSE) 138. The EVSE 138 can provide circuits and controls to control the energy transfer between the power source 136 and the plug-in vehicle 100. The external power source 136 can provide DC or AC power to the EVSE 138. The EVSE 138 can have a charging connector 140 for plugging into a charging port 134 of the plug-in vehicle 100. The charging port 134 can be any type of port configured to transfer power from the EVSE 138 to the plug-in vehicle 100. The charging port 134 can be electrically connected to a charger or on-board power conversion module 132 of the plug-in vehicle 100. The power conversion module 132 may condition the power supplied from the EVSE 138 to provide the appropriate voltage and current levels to the HVMA battery 120. The power conversion module 132 may interact with the EVSE 138 to coordinate power delivery to the plug-in vehicle 100. The charging connector 140 may have a first set of pins 154 that mate with a second set of pins 156 of the charging port 134. In this way, the HVMA battery 120 may be charged using plug-in charging, where the HVMA battery 120 is coupled to the external power source 136 via the charging port 134. Alternatively, the various components described as being electrically coupled may transfer power using wireless inductive coupling.

[0021] In some embodiments, the plug-in vehicle 100 may additionally or alternatively be configured to charge the HVMA battery 120 via inductive charging, wherein the charging connector is not plugged into the charging port to charge the HVMA battery 120. In these embodiments, the methods described herein may function similarly. For example, in response to a rate of change of a difference in maximum cell voltage deviation of at least one cell array of a high voltage multi-array battery exceeding a predetermined threshold, a method for a vehicle configured to perform inductive charging may include suspending charging and recording a diagnostic trouble code (DTC) in a memory of the vehicle.

[0022] Adjustment of the powertrain 106 between the various operating modes and control of operation within each mode may be performed based on a vehicle control system 124 including a controller 126. The controller 126 may be a microcomputer including elements such as a microprocessor unit, input / output ports, an electronic storage medium (e.g., a read-only memory chip) for executable programs and calibration values, a random access memory, a keep-alive memory, and a data bus. The storage medium may be programmed with computer-readable data representing instructions that are executable by a processor for performing the methods described below as well as other variations that are anticipated but not specifically listed. In one example, the controller 126 may be a powertrain control module (PCM).

[0023] The controller 126 may receive various signals from sensors 128 coupled to various areas of the plug-in vehicle 100. For example, the sensors 128 may include sensors at the first motor 114 and the second motor 116 for measuring motor speed and motor temperature, pedal position sensors for detecting depression of an operator-actuated pedal (such as an accelerator pedal or a brake pedal), speed sensors at the wheels 102, and the like. Vehicle acceleration is proportional to the accelerator pedal position (e.g., depression degree). After receiving signals from the various sensors 128, the controller 126 processes the received signals and employs various actuators 130 of the plug-in vehicle 100 to adjust the powertrain operation based on the received signals and instructions stored on a memory 152 (e.g., an electronic storage medium) of the controller 126. For example, the controller 126 may receive an indication of depression of the brake pedal, thereby signaling a desire to reduce vehicle speed. In response, the controller 126 may command at least one of the first motor 114 and the second motor 116 to operate as a generator to recharge the HVMA battery 120. In addition, as referenced Figure 4As further described, monitoring battery cell degradation includes suspending plug-in charging and recording a diagnostic trouble code (DTC) in memory 152 in response to a rate of change of a difference in maximum cell voltage deviation of at least one cell array exceeding a predetermined threshold. Suspending plug-in charging may include one or more of: controlling an actuator to disconnect one or more contactors 142 to isolate the HVMA battery 120 from other components, and controlling an actuator to retract a second set of pins 156 of the charging port 134 to disconnect the plug-in vehicle 100 from the charging connector 140. As shown, suspending plug-in charging includes transitioning from a state where plug-in charging is actively occurring by stopping plug-in charging and not plug-in charging.

[0024] As this article about Figure 2 As further described, the HVMA battery 120 may include a battery energy control module (BECM) 150 that may be located in the HVMA battery 120 and monitor the battery cell voltage, battery current, and battery cell temperature of each battery cell of each array of the HVMA battery 120. The BECM 150 may be communicatively coupled to the controller 126 and further directly or indirectly control the amount of charging current entering and / or leaving the HVMA battery 120. The BECM 150 may also be configured to run diagnostic checks to evaluate the operating capability of the HVMA battery 120 during periods of detected cell degradation and / or loss of function. Such diagnostic tests may include analysis of changes in voltage differentials (e.g., changes in battery voltage with respect to time, dV / dt), such as with respect to Figures 3 to 5 As further described, for example, detecting a voltage signature such as a negative dV / dt spike during charging of the HVMA battery 120 may indicate cell degradation, such as a cell short.

[0025] Steering Figure 2 , a schematic diagram 200 of a HVMA battery 120 is shown. The HVMA battery 120 can be constructed of various chemical formulations, such as lead acid, nickel-metal hydride (NIMH), or lithium ion (Li). Figure 2In the illustrated embodiment, the HVMA battery 120 includes a simple series configuration of N battery cell arrays 202. In other embodiments, the HVMA battery 120 may include any number of separate battery cell arrays connected in series, in parallel, or some combination thereof. Each of the N battery cell arrays 202 includes a plurality of battery cells 204. Each of the plurality of battery cells 204 of the battery cell arrays may be similarly configured (e.g., having the same voltage capacity) or may have a different configuration. Each of the N battery cell arrays 202 may include the same number of battery cells or a different number of battery cells, and the battery cells of each of the N battery cell arrays 202 may have the same or different configuration relative to the battery cells of the other arrays of the N battery cell arrays 202. The HVMA battery 120 also includes a positive terminal 216 and a negative terminal 218 that may couple the HVMA battery 120 to power elements (such as the first and second electric machines 114 and 116 ) (eg, via the power electronics module 148 ) and enable the HVMA battery 120 to selectively provide power thereto.

[0026] The HVMA battery 120 includes a sensor module 208 for measuring and monitoring characteristics of the HVMA battery 120, such as temperature, current, and voltage. A single battery cell of the array may be the smallest structure configured to be directly measured and monitored by the sensor module 208. For example, the terminal voltage, current, and temperature of each of the plurality of battery cells 204 may be measured using the sensor module 208. In some embodiments, the sensor module 208 includes additional modules for measuring specific characteristics of the plurality of battery cells 204. For example, the HVMA battery 120 may also include one or more current measurement sensors 210, voltage measurement sensors 212, and temperature measurement sensors 214. The HVMA battery 120 may include additional sensor modules 208 configured to measure characteristics of the HVMA battery 120 at the battery level and / or at the array level. Sensors for capturing battery-level measurements and / or array-level measurements may be shared among the N battery cell arrays 202. In other embodiments, the HVMA battery 120 may include N sensor modules 208 (eg, equal to the number of N battery cell arrays) to measure characteristics of the battery cells in each array.

[0027] A battery management system that manages the voltages of the battery cells of the N battery cell array 202 measured by at least one sensor module 208 may include one or more controllers, such as a BECM 150. The BECM 150 may be communicatively coupled to the battery-level, array-level, and cell-level sensors of the HVMA battery 120 and the controller 126 of the plug-in vehicle 100. Each of the at least one sensor module 208 may transmit the measured values ​​to the BECM 150 for further processing and coordination. In some configurations, the functionality of the sensor module 208 may be incorporated into the interior of the BECM 150. For example, the hardware of the sensor module 208 may be integrated as part of the circuitry of the BECM 150, and the BECM 150 may process the raw signals. The BECM 150 may also include non-volatile memory so that data may be retained when the BECM 150 is in a shutdown condition, and the retained data may be available at the next startup condition of the BECM 150. The BECM 150 may also include a communication interface for communicating with (e.g., Figure 1 ) one or more contactors 142 interact to open and close the circuit of the contactor 142.

[0028] Figure 3 A graphical representation 300 of a curve 302 of a change in voltage of a battery cell with respect to a change in time (dV / dt) is shown. Voltage is shown on the vertical axis and time is shown in seconds on the horizontal axis. The rate of change of voltage of the battery cell with respect to time (dV / dt) is plotted to generate the curve 302. The battery cell may be a battery cell in the plurality of battery cells 204 of the array of N battery cells 202 of the HVMA battery 120, as described with respect to FIG. Figure 2 The battery cell may be a single battery cell having a single anode and a single cathode, or may be a battery cell having multiple cathodes and multiple anodes, wherein the multiple cathodes and the multiple anodes are connected in parallel, in series, or a combination thereof.

[0029] The curve 302 is captured during plug-in charging of the HVMA battery 120. Herein, the curve 302 shows a sudden change in the voltage of the battery cell occurring at time 308. The voltage of the battery cell may decrease from a first voltage range between 4.085V and 4.090V to a voltage minimum 312 at time 308 within a first duration 310. The voltage of the battery cell may then partially rebound to a second voltage range between 4.075V and 4.080V within a second duration 314. The curve 302 may be monitored by the BECM 150 and / or the controller 126, as described with respect to FIG. Figure 1 and Figure 2 As described. Figure 4As further described. For example, the BECM 150 and / or the controller 126 may be configured to compare the rate of change of the curve 302 to a predetermined threshold rate of change. The predetermined threshold rate of change may be a non-zero positive value derived from one or more battery cell characteristics, the one or more battery cell characteristics including battery cell life, battery cell capacity, battery cell state of charge, battery cell current, battery cell chemistry, battery cell structure, and battery cell usage. For example, the predetermined threshold rate of change may be a maximum rate of change of battery cells of a high voltage multi-array battery that are continuously charged without overloading the voltage capacity of the battery cells.

[0030] The graphical representation 300 also includes a plurality of curves 316 of voltage of additional battery cells versus time. The additional battery cells may be other battery cells of the same array as the battery cells depicted by curve 302, or may be battery cells of a different array in the same HVMA battery 120 as the battery cells depicted by curve 302. Over the duration shown in the graphical representation 300, the voltage of the additional battery cells as shown by the plurality of curves 316 is within a third voltage range between 4.085V and 4.100V.

[0031] can (for example, by Figure 2 The sensor module 208 of the controller 126 measures the voltage of the battery cell over time (e.g., V(t)) and records it in the memory of the controller (e.g., the memory 152 of the controller 126). Figure 4 As further described, the voltage of each of the battery cells of the array can be used to determine the rate of change of the difference in the maximum cell voltage deviation of the cell array. In response to the determined rate of change of the difference in the maximum cell voltage deviation, the behavior of the HVMA battery 120 can be adjusted, including terminating plug-in charging of the HVMA battery 120.

[0032] Figure 4 A flow chart of a method 400 for monitoring battery cell degradation based on a rate of change of a difference in maximum cell voltage deviations of at least one cell array of a high voltage multi-array battery is shown. In response to the rate of change of the difference in maximum cell voltage deviations exceeding a predetermined threshold, plug-in charging is aborted and a diagnostic trouble code (DTC) is recorded in memory. The controller (e.g., BECM 150 and / or controller 126) may be configured to monitor the degradation of a battery cell based on instructions stored in the memory of the controller and in combination with sensors of the plug-in vehicle (such as those described above). Figure 1 The controller may use the signals received by the sensors described in the examples to execute instructions for executing method 400. According to the method described below, the controller may use the actuators of the plug-in vehicle to adjust the operation of the high voltage multi-array battery. Figure 1The method 400 is described for a plug-in vehicle 100 of FIG. 1 , wherein the high voltage multi-array battery may be a HVMA battery 120. The method 400 may be implemented in other high voltage multi-array battery systems that are charged via plug-in charging without departing from the scope of the present disclosure. When the plug-in vehicle 100 is an electric vehicle or a plug-in hybrid electric vehicle, the method 400 is performed during plug-in charging of the HVMA battery 120. Alternatively, when the plug-in vehicle 100 is a hybrid electric vehicle that is not connected to an external power source for plug-in charging, the method 400 may be performed when the rate of change of the battery current (di / dt) is low (e.g., the battery has a slow discharge rate).

[0033] At 402, a first parameter representing the instantaneous maximum cell voltage deviation of each cell array in a battery (eg, HVMA battery 120) is calculated. Figure 1 to Figure 2 As described, the HVMA battery 120 includes N battery cell arrays, each battery cell array including a plurality of battery cells. The method 400 may be used to identify degradation of the HVMA battery 120 at the array level using measurements captured at the battery cell level. At 404, the voltage of each battery cell of the array in the N battery cell arrays is captured. For example, the voltage of each battery cell may be captured by a sensor module (e.g., sensor module 208) electrically coupled to one or more battery cells. In some embodiments, the sensor module 208 may be used to capture the voltage of a single battery cell, the corresponding voltages of a plurality of battery cells of the array, and / or the corresponding voltages of a plurality of battery cells from a plurality of arrays. In further embodiments, more than one sensor module 208 may be included in the HVMA battery 120. For example, the HVMA battery 120 may include N sensor modules corresponding to the N battery cell arrays. In some embodiments, the voltages of all battery cells of the first array may be captured and processed as described herein with respect to method 400 before capturing the voltages of battery cells of additional arrays (e.g., the second array, the Nth array, and arrays therebetween). In other embodiments, the voltages of all battery cells of all arrays of the HVMA battery 120 may be captured at operation 404 and the voltages may be processed simultaneously according to method 400.

[0034] Using the battery cell voltages captured at operation 404, battery cells of the array having a maximum voltage and a minimum voltage of the array are identified at 406. For example, a first battery cell having a maximum voltage compared to the voltages of all battery cells of the first array and a second battery cell having a minimum voltage compared to the voltages of all battery cells of the first array are identified. After identifying the battery cells of the array having the maximum voltage and the minimum voltage, an average voltage of the battery cells in the array is calculated at 408 excluding the voltages of the cells having the maximum voltage and the minimum voltage. For example, the average voltage of the first array is calculated by averaging all battery cell voltages captured at operation 404 except the cell voltages of the first cell and the second cell.

[0035] Using the battery cell voltage captured at operation 404 and the average voltage of the battery cells of the array calculated at operation 408, a first parameter representing the instantaneous maximum cell voltage deviation of the array of cells in a battery (e.g., HVMA battery 120) is calculated. For example, the first parameter may be represented as dV max , and calculated according to Equation 1:

[0036] dV max = abs(max(CellnV – average value of cells in the array excluding the maximum and minimum cells V))(1)

[0037] Wherein "abs" is an absolute value function (e.g., |x|, where x is a positive or negative value), "max" is a maximum function (e.g., identifying a maximum value in a data set), and "CellnV" represents a data set that includes the voltage of each battery cell of the array (e.g., captured at operation 404). Thus, Equation 1 calculates the difference between the voltage of each battery cell of the array and the average voltage of the battery cells of the array (excluding the maximum voltage and the minimum voltage identified at operation 406), and identifies the absolute value of the maximum value of the difference. The "maximum value of the difference" identified using the max function can be a positive or negative value (e.g., where the voltage of the battery cell is greater than or less than the average voltage of the battery cells of the array, respectively), and the absolute value function provides the maximum value of the difference as a positive number. In other words, calculating the first parameter includes calculating the varying maximum cell voltage deviation in the array of HVMA batteries 120, rather than calculating the derivative of each cell voltage of each cell of each cell array of the HVMA batteries 120. This can reduce computational demands on the processor and reduce detection time, such as with respect to Figure 5 Further described.

[0038] At 410, a second parameter is calculated that represents the rate of change of the first parameter based on the difference between the first parameter and the historical moving average of the first parameter. In other words, the second parameter is the rate of change of the difference in the maximum battery voltage deviation, represented as ΔdVmax / dt and calculated according to Equation 2:

[0039] ΔdV max =(dV max_瞬时 -dV max_移动平均 ) (2)

[0040] Among them, "dV max_瞬时 ” is the dV calculated according to Equation 1 max , and represents the voltage change under a specific situation (for example, the case of capturing the battery cell voltage), and “dV max_移动平均 "It is dV max_瞬时的历史值 The historical value may be a dV that has been calculated in a previous execution of the method 400 and stored in a memory of the controller (eg, the memory 152 of the controller 126 ). max_瞬时 As for the value of Figure 5 As further described, in some embodiments, dV may be calculated using stored data of battery cell voltages of a corresponding array during execution of method 400. max_移动平 all.

[0041] By solving for the rate of change of the difference in maximum cell voltage deviations of an array of cells of the HVMA battery 120, degradation of one or more battery cells of the array may be identified. At 412, the second parameter is compared to a predetermined threshold rate of change. The predetermined threshold rate of change may be, for example, a non-zero positive value that represents an expected rate of change of the difference in maximum cell voltage deviations established using characteristics of the array, such as the number and voltage capacity of the battery cells of the array. The expected rate of change may reflect the rate at which the voltage of the battery cells of the array increases during plug-in charging when plug-in charging is not impeded by factors that may slow charging. Thus, when the rate of change of the difference in maximum cell voltage deviations of at least one array of cells is high, there may be a greater-than-expected change in the charging rate, which may indicate degradation of one or more battery cells of the array. For example, in Figure 3 The sudden change in voltage occurring at time 308 in may be 0.015 V / s. On average, the expected rate of change (eg, a predetermined threshold) may be 0.001 V / s. Figure 5 Additional examples where the rate of change exceeds a predetermined threshold are described.

[0042] At 412, it is determined whether the second parameter is greater than a predetermined threshold. Figure 3In the example shown, the second parameter (e.g., 0.015 V / s) exceeds a predetermined threshold (e.g., 0.001 V / s) at time 308. If the second parameter does not exceed the predetermined threshold, method 400 proceeds to 414, where plug-in charging continues without adjustment. Method 400 then returns to the beginning to continuously monitor the rate of change of the difference in maximum cell voltage deviation of the array of high voltage multi-array batteries.

[0043] If at 412 the second parameter is greater than the predetermined threshold, the method 400 proceeds to 416 to add a value to the integer count. Each time the second parameter of the array of high voltage multi-array batteries is determined to be greater than the predetermined threshold, the incremental counter may add the count to the integer count stored in the non-transitory memory of the controller (e.g., the memory 152 of the controller 126). In this way, the integer count is incremented by one to track the number of times the rate of change of the difference in the maximum cell voltage deviation of the array of cells may indicate degradation of one or more battery cells.

[0044] At 418, the increment counter is referenced to determine if the count is greater than a count threshold. The count threshold may be a non-zero positive integer indicating a maximum number of occurrences that the second parameter is greater than a predetermined threshold before the array may degrade. The count threshold may be set by a manufacturer, user, and / or dealer of the high voltage multi-array battery and / or the system in which it is integrated. If the count is not greater than the count threshold at 418, method 400 proceeds to 414 and plug-in charging continues unchanged.

[0045] If the count is greater than the count threshold at 418, the method proceeds to 420 to abort plug-in charging and record a diagnostic trouble code (DTC) in the memory of the controller. Aborting plug-in charging (e.g., aborting the plug-in charging operation) may include the controller sending a signal to one or more contactors (e.g., one or more contactors 142) to disconnect the HVMA battery 120 and isolate it from other components of the system (e.g., the first motor 114 and the second motor 116). In some embodiments, aborting plug-in charging may additionally or alternatively include disconnecting the charging connector 140 from the charging port 134 of the plug-in vehicle 100, such as by adjusting the configuration of the charging port (e.g., retracting the second set of pins 156 of the charging port 134 to not contact the first set of pins 154 of the charging connector 140) to disconnect the charging connector from the charging port. Aborting plug-in charging may also include adjusting the operation of the power conversion module 132 to stop the power supplied by the charging connector 140 to the charging port 134 from being delivered to the HVMA battery 120. Recording the DTC may also include outputting a notification to a display device, such as a dashboard or a heads-up display of a vehicle (e.g., plug-in vehicle 100), indicating that plug-in charging has been suspended. Operations included in suspending plug-in charging may occur for a first duration, where the first duration may be configured by the manufacturer and / or user. For example, a configuration of a charging port may be adjusted to prevent a charging connector from being connected to the charging port for the first duration.

[0046] In addition to suspending plug-in charging and recording DTCs, in response to the count being greater than the count threshold, the controller may also perform a battery power-off event, and may further enable an inhibit restart action for the HVMA battery 120. The inhibit restart action may include preventing the HVMA battery 120 from being powered on and / or charged via plug-in charging for a first duration, wherein the first duration is monitored by the controller. In some embodiments, after suspending plug-in charging, the method further includes monitoring the HVMA battery 120 for a potential thermal event. For example, due to rapid charging of one or more battery cells, the rate of change of the difference in the maximum cell voltage deviation may exceed a predetermined threshold, which may cause the battery cells, arrays, and / or HVMA battery 120 to heat to a temperature at which degradation due to overheating may occur. Therefore, monitoring for potential thermal events may include monitoring the temperature of the HVMA battery 120 via one or more temperature measurement sensors 214. For example, the temperature and the rate of temperature change of the HVMA battery 120 may be monitored, and in response to the temperature exceeding the temperature threshold and / or the rate of temperature change exceeding the temperature rate of change threshold, the controller may output a notification to a display device indicating that a thermal event has occurred. Monitoring for potential thermal events may also include outputting a notification to a display device (e.g., a dashboard or heads-up display of the plug-in vehicle 100) indicating a need for external thermal monitoring, such as using a thermal monitoring device that is external and separate from the vehicle and that can be selectively coupled to the HVMA battery 120.

[0047] Figure 5 A prophetic timing diagram 500 is shown illustrating operation of a high voltage multi-array battery of a vehicle (e.g., HVMA battery 120 of plug-in vehicle 100), wherein in response to the rate of change of the difference in maximum cell voltage deviation of at least one cell array of the high voltage multi-array battery exceeding a predetermined threshold, plug-in charging is aborted and a DTC is recorded in the vehicle's memory. Figure 5The control method for the operation of the high voltage multi-array battery shown may be the same or similar to the series of actions described above with reference to method 400. Instructions for executing the control method described in timing diagram 500 may be executed by a controller (e.g., controller 126 and / or BECM 150) based on instructions stored in a memory of the controller and in conjunction with sensory feedback received from components of a system (e.g., plug-in vehicle 100) in which the high voltage multi-array battery is integrated, including current measurement sensors, voltage measurement sensors, and temperature measurement sensors (e.g., sensor module 208). In the prophetic example, the controller uses the voltage of the battery cells of the high voltage multi-array battery to determine whether the rate of change of the difference in the maximum cell voltage deviation of at least one cell array of the high voltage multi-array battery is greater than a predetermined threshold. In response to the rate of change exceeding the predetermined threshold, the controller may execute to terminate plug-in charging and record a DTC in the memory of the controller. Figure 5 In FIG. 5 , the horizontal axis represents time, and the vertical labels t0 to t5 identify relevant times in the timing diagram 500 for high voltage multi-array battery control.

[0048] The timing diagram 500 shows graphs 502, 504, 506, 508, 510, 512, and 514 showing states of components and / or control settings of a vehicle system (e.g., plug-in vehicle 100) over time. Graph 502 indicates the voltage of each battery cell of an array, wherein each of graphs 502a, 502b, 502c, 502d, 502e, and 502f represents a battery cell of the array. Graph 504 indicates an instantaneous maximum cell voltage deviation of the array. For example, as described with respect to operation 402 of method 400, the instantaneous maximum cell voltage deviation is calculated by identifying the voltage of each cell of the array (e.g., as shown in graph 502), identifying the cell of the array having the maximum voltage and the minimum voltage of the array, identifying the average voltage of the cells in the array excluding the cell having the maximum voltage and the minimum voltage, and identifying the maximum difference between the cell voltage and the average voltage of the cells in the array. Graph 506 indicates the rate of change of the difference in maximum cell voltage deviation of at least one cell array of the high voltage multi-array battery. Figure 4As described, the rate of change shown in graph 506 is the difference between the instantaneous maximum cell voltage deviation (e.g., graph 504) and the historical moving average. A first threshold 516 is indicated in graph 506. The first threshold 516 is a non-zero positive threshold and is the predetermined threshold mentioned above, which, when the rate of change (e.g., graph 506) exceeds the predetermined threshold, causes the controller to terminate plug-in charging and record a diagnostic trouble code (DTC) in the vehicle's memory. Graph 508 shows an incremental counter, which is an integer count recorded each time it is determined that the rate of change (e.g., graph 506) is greater than a predetermined threshold (e.g., first threshold 516). Graph 508 includes a second threshold 518, which is a non-zero positive threshold incremental counter. In Figure 5 In the example of , when the rate of change (e.g., graph 506) exceeds a predetermined threshold (e.g., first threshold 516) for a number of times equal to second threshold 518, plug-in charging is terminated and the DTC is recorded in the memory of the plug-in vehicle. Graph 510 shows the status of plug-in charging of the plug-in vehicle. Graph 512 shows whether the contacts of the high-voltage multi-array battery (e.g., contactor 142) are open (e.g., connecting the high-voltage multi-array battery to components of the plug-in vehicle, such as the first motor 114 and the second motor 116) or closed (e.g., separating the high-voltage multi-array battery from components of the plug-in vehicle). Graph 514 shows whether the pins of the charging port (e.g., the second set of pins 156 of the charging port 134) are extended (e.g., to connect the charging port to the charging connector 140 to enable plug-in charging) or retracted (e.g., to prevent the charging port from connecting to the charging connector and disable plug-in charging).

[0049] From t0 to t1, the voltage of the battery cells of the array is approximately unchanged, so the instantaneous maximum cell voltage deviation calculated as described with respect to equation 1 and operation 402 can be relatively unchanged. Because the instantaneous maximum cell voltage deviation is relatively unchanged, the rate of change of the difference in the maximum cell voltage deviation is approximately zero. The value of the incremental counter is zero. Plug-in charging of the high-voltage multi-array battery is turned off. The contacts are closed, thereby electrically connecting the high-voltage multi-array battery to components of the plug-in vehicle. The charging port pins are retracted, thereby preventing the high-voltage multi-array battery from being electrically connected to an external power source (e.g., external power source 136) via the charging connector connected to the charging port. The plug-in vehicle may be turned off, so the voltage of the battery cells may not decrease.

[0050] At t1, plug-in charging of the high-voltage multi-array battery is actuated. Plug-in charging includes connecting the high-voltage multi-array battery to an external power source (e.g., external power source 136) via a charging connector to a charging port. Therefore, the charging port pins extend to contact the pins of the charging connector (e.g., the first set of pins 154). The contacts remain closed to enable power to be delivered from the charging port to the high-voltage multi-array battery. When plug-in charging begins, between t1 and t2, the voltage of each battery cell increases. The voltage of the battery cells shown by graphs 502a, 502b, 502c, 502e, and 502f gradually increases at approximately the same rate. The voltage of the battery cell shown by graph 502d (shown in dotted lines for clarity) increases at a rate significantly greater than the rate of the other battery cells of the array. The instantaneous maximum voltage of the array increases, which corresponds to the battery cells of the array (e.g., the battery cells shown by graph 502d) having a voltage greater than the voltage of the other battery cells of the array. The rate of change of the difference in the maximum cell voltage deviation of the cell array also increases. For example, by comparing the dV between t1-t2 and t0-t1 max (eg, graph 504 ) to calculate a rate of change (eg, graph 506 ).

[0051] At t2, as dV max Increase, ΔdV max Increases to greater than the first threshold 516, which may indicate degradation of at least one battery cell of the array. The incremental counter increases by one count. Between t2 and t3, plug-in charging continues, and the battery cell voltages shown by graphs 502a, 502b, 502c, 502e, and 502f continue to increase. The battery cell voltage shown by graph 502d is substantially constant. Thus, between t2 and t3, dV max and ΔdV max Gradually decrease.

[0052] Between t3 and t4, the voltage of the battery cells shown by graphs 502a, 502b, 502d, 502e, and 502f is substantially constant. For example, the battery cells may be fully charged. Plug-in charging continues, and the plug-in vehicle may be turned off (e.g., the motor or auxiliary components have no power demand on the high voltage multi-array battery). The voltage of the battery cells shown by graph 502c (shown as a dotted line for clarity) decreases between t3 and t5. The instantaneous maximum voltage deviation of the array increases, which corresponds to a battery cell of the array (e.g., a battery cell shown by graph 502d) having a voltage that is different from the voltage of other battery cells of the array. As described with respect to method 400, calculating the instantaneous maximum voltage deviation includes calculating the absolute value of the maximum voltage, so that when the voltage of the battery cell decreases, the instantaneous maximum voltage is shown as a positive number. The rate of change of the difference in the maximum cell voltage deviation of the cell array also increases.

[0053] At t4, as dV max Increase, ΔdV max Increases again to be greater than the first threshold 516, which may indicate degradation of at least one battery cell of the array. The incremental counter increases by one count to two. Figure 5 In an embodiment of the present invention, when the value of the incremental counter is equal to the count threshold (e.g., the second threshold 518), plug-in charging of the plug-in vehicle is terminated. At t5, plug-in charging is terminated, the contacts are actuated to the disconnected position, and the charging port pins are retracted, thereby electrically isolating the high-voltage multi-array battery from the external power source. As described herein, the method may also include: recording the DTC in a memory of the plug-in vehicle; outputting a notification indicating that plug-in charging has been terminated; and monitoring thermal events.

[0054] In this way, the efficiency of plug-in charging of a high-voltage multi-array battery of a plug-in vehicle can be improved, and the usable life of the battery cells of the high-voltage multi-array battery can be increased. By reducing the number of calculations used to monitor the battery cell voltage, the time to detect battery cell degradation can be reduced, and plug-in charging can be stopped earlier than conventional methods. Recording DTCs and outputting notifications can indicate potential battery cell degradation events to the user before battery cell degradation advances to the level of additional elements that affect vehicle operation. In addition, automatically suspending plug-in charging when potential degradation of one or more battery cells is detected via the rate of change can improve the efficiency of plug-in charging by stopping power delivery to battery cells that may not be able to store power. The technical effects of monitoring battery cell degradation in a high-voltage multi-array battery are to reduce the time to detect degradation, improve calculation efficiency (e.g., reduce the number of calculations), and improve charging efficiency.

[0055] The present disclosure also provides support for a method for detecting battery cell degradation during plug-in charging of a high voltage multi-array battery of a vehicle, the method comprising: in response to a rate of change of a difference in maximum cell voltage deviations of at least one cell array of the high voltage multi-array battery exceeding a predetermined threshold, suspending plug-in charging and recording a diagnostic trouble code (DTC) in a memory of the vehicle. In a first example of the method, the rate of change of the difference in the maximum cell voltage deviations is the difference between an instantaneous maximum cell voltage deviation and a historical moving average of the maximum cell voltage deviations. In a second example of the method (optionally including the first example), the instantaneous maximum cell voltage deviation is calculated by the following operations: identifying the voltage of each cell in an array of the high voltage multi-array battery; identifying a first cell of the array having a maximum voltage of the cells in the array; identifying a second cell of the array having a minimum voltage of the cells in the array; and calculating an average voltage of the array, excluding the first cell and the second cell when calculating the average voltage. In a third example of the method (optionally including one or both of the first and second examples), calculating the instantaneous maximum battery voltage deviation includes calculating the change in battery voltage increments in the array of the high-voltage multi-array battery instead of calculating the derivative of each cell voltage of each cell in each cell array of the high-voltage multi-array battery. In a fourth example of the method (optionally including one or more or each of the first to third examples), a count of cases in which the rate of change of the difference in the maximum cell voltage deviation exceeds the predetermined threshold is recorded, and the plug-in charging is suspended and the DTC is recorded in response to the count exceeding the count threshold. In a fifth example of the method (optionally including one or more or each of the first to fourth examples), the method further includes: in response to the rate of change of the difference in the maximum cell voltage deviation of at least one cell array of the high-voltage multi-array battery exceeding the predetermined threshold, performing battery power-off of the high-voltage multi-array battery. In a sixth example of the method (optionally including one or more or each of the first to fifth examples), the method further includes: in response to the rate of change of the difference of the maximum cell voltage deviation of at least one cell array of the high-voltage multi-array battery exceeding the predetermined threshold, enabling the prohibition restart action of the high-voltage multi-array battery for a first duration. In a seventh example of the method (optionally including one or more or each of the first to sixth examples), the method further includes: in response to the rate of change of the difference of the maximum cell voltage deviation of at least one cell array of the high-voltage multi-array battery exceeding the predetermined threshold, monitoring the high-voltage multi-array battery for potential thermal events and outputting a notification indicating the need for external thermal monitoring.In an eighth example of the method (optionally including one or more or each of the first to seventh examples), monitoring potential thermal events includes monitoring the temperature and temperature change rate of the high-voltage multi-array battery, and in response to the temperature exceeding a temperature threshold or the temperature change rate exceeding a temperature change rate threshold, outputting a thermal event notification to a display device and recording a thermal DTC in the memory of the vehicle.

[0056] The present disclosure also provides support for a plug-in vehicle, the plug-in vehicle comprising: a charging port; a high-voltage multi-array battery; a power conversion module, the power conversion module selectively coupling the charging port to the high-voltage multi-array battery; and a battery energy control module (BECM), the BECM comprising instructions stored in a non-transitory memory, the instructions when executed causing the BECM to: calculate a first parameter representing an instantaneous maximum cell voltage deviation of each cell array of the high-voltage multi-array battery; calculate a second parameter representing a rate of change of the first parameter based on a difference between the first parameter and a historical moving average of the first parameter; and in response to the second parameter of at least one cell array of the high-voltage multi-array battery exceeding a predetermined threshold, suspend plug-in charging and record a diagnostic trouble code (DTC) in a memory of the plug-in vehicle. In a first example of the system, each array of the high-voltage multi-array battery includes a plurality of cells, and the maximum cell voltage deviation of each array is calculated by calculating the maximum value of the difference between the cell voltage of a first cell of the array and the average voltage of the battery cells of the array excluding the first cell, the second cell having the maximum voltage, and the third cell having the minimum voltage. In a second example of the system (optionally including the first example), suspending the plug-in charging includes adjusting the power conversion module to stop the power supplied by the charger to the charging port from being delivered to the high-voltage multi-array battery. In a third example of the system (optionally including one or both of the first and second examples), suspending the plug-in charging and recording the DTC also includes outputting a notification to a display device, the notification indicating that the plug-in charging has been suspended. In a fourth example of the system (optionally including one or more or each of the first to third examples), suspending the plug-in charging also includes adjusting the configuration of the charging port to disconnect the charging connector from the charging port. In a fifth example of the system (optionally including one or more or each of the first to fourth examples), suspending the plug-in charging also includes adjusting the configuration of the charging port to prevent the charging connector from being connected to the charging port for a first duration.

[0057] The present disclosure also provides support for a method for operating a multi-array battery pack of a vehicle, the method comprising: for each array of the multi-array battery pack, calculating a first parameter representing a change in an instantaneous maximum cell voltage deviation by calculating the maximum value of the difference between the battery cell voltage of a first cell of the array and the average voltage of the remaining cells of the array excluding the first cell, the second cell with the maximum voltage of the array, and the third cell with the minimum voltage of the array; calculating a second parameter representing the difference between the change in the instantaneous maximum cell voltage deviation and the change in the historical moving average cell voltage deviation of the array; in response to the second parameter exceeding a predetermined threshold, adding a value to an integer count; and in response to the integer count exceeding the count threshold, suspending plug-in charging and recording a diagnostic trouble code (DTC) in a memory of the vehicle. In a first example of the method, the method also includes: in response to the integer count exceeding the count threshold, disabling plug-in charging and power output of the multi-array battery pack for a first duration. In a second example of the method (optionally including the first example), the predetermined threshold represents a certain battery cell voltage above which the temperature of the multi-array battery pack exceeds an operating temperature. In a third example of the method (optionally including one or both of the first and second examples), the method further includes: in response to the integer count exceeding the count threshold, monitoring the multi-array battery pack for potential thermal events by continuously comparing the temperature of each array of the multi-array battery pack to a temperature threshold, and in response to the temperature exceeding the temperature threshold, discharging the multi-array battery pack, outputting a thermal event notification to a display device, and recording a thermal DTC in the memory of the vehicle. In a fourth example of the method (optionally including one or more or each of the first to third examples), the method further includes: in response to the integer count exceeding the count threshold, monitoring the multi-array battery pack for potential thermal events by continuously comparing the temperature change rate of each array of the multi-array battery pack with a temperature change rate threshold, and in response to the temperature change rate exceeding the temperature change rate threshold, discharging the multi-array battery pack, outputting a thermal event notification to a display device, and recording a thermal DTC in the memory of the vehicle.

[0058] Figure 1 to Figure 2An exemplary configuration with relative positioning of various components is shown. Unless otherwise specified, at least in one example, if shown as directly contacting each other or directly connected, such elements may be referred to as direct contact or direct connection, respectively. Similarly, at least in one example, elements shown as adjacent or adjacent to each other may be adjacent or adjacent to each other, respectively. As an example, components that are coplanarly contacted with each other may be referred to as coplanar contact. As another example, in at least one example, elements that are positioned apart from each other with only space between them and no other components may be referred to as such. As another example, elements that are shown as above / below each other, on opposite sides or on the left / right side of each other may be referred to as such relative to each other. In addition, as shown in the accompanying drawings, in at least one example, the topmost element or the vertex of the element may be referred to as the "top" of the component, and the bottommost element or the bottommost point of the element may be referred to as the "bottom" of the component. As used herein, top / bottom, upper / lower, above / below may be relative to the vertical axis of the accompanying drawings, and are used to describe the positioning of the elements of the accompanying drawings relative to each other. Thus, in one example, an element shown as being above other elements is located directly above the other elements. As another example, the shapes of the elements depicted in the drawings may be referred to as having these shapes (e.g., such as being circular, linear, planar, curved, rounded, chamfered, angled, etc.). In addition, in at least one example, elements shown as intersecting each other may be referred to as intersecting elements or intersecting each other. Further, in one example, an element shown as being within another element or being shown as being outside another element may be referred to as such.

[0059] It should be noted that the exemplary control and estimation procedures included herein can be used with various vehicle system configurations. The control methods and procedures disclosed herein can be stored as executable instructions in a non-transitory memory and can be executed by a control system including a controller in combination with various sensors, actuators and other engine hardware. The specific procedures described herein can represent one or more of any number of processing strategies (such as event-driven, interrupt-driven, multi-tasking, multi-threading, etc.). Therefore, the various actions, operations and / or functions shown can be executed in the sequence shown, executed in parallel, or omitted in some cases. Similarly, the processing order is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the actions, operations and / or functions shown can be repeatedly performed according to the specific strategy used. In addition, the described actions, operations and / or functions can graphically represent the code in the non-transitory memory of the computer-readable storage medium to be programmed into the engine control system, wherein the described actions are implemented by executing instructions in a system including various engine hardware components in combination with an electronic controller.

[0060] It should be understood that the configurations and procedures disclosed herein are exemplary in nature, and these specific embodiments should not be considered to have a limiting meaning, as many variations are possible. Unless explicitly stated to the contrary, the terms "first," "second," "third," etc. are not intended to indicate any order, position, quantity, or importance, but are merely used as markers to distinguish one element from another. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations and other features, functions, and / or properties disclosed herein.

[0061] As used herein, unless otherwise specified, the term "about" is interpreted to mean a range of ±5%.

[0062] The appended claims particularly point out certain combinations and subcombinations regarded as novel and non-obvious. These claims may refer to "an" element or "a first" element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amendment of the present claims or by presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, are also deemed to be included in the subject matter of the present disclosure.

[0063] According to the present invention, a method for detecting battery cell degradation during plug-in charging of a high voltage multi-array battery of a vehicle includes: in response to the rate of change of the difference of the maximum cell voltage deviation of at least one cell array of the high voltage multi-array battery exceeding a predetermined threshold, terminating the plug-in charging and recording a diagnostic trouble code (DTC) in the memory of the vehicle.

[0064] In one aspect of the present invention, the change rate of the difference in the maximum cell voltage deviation is the difference between the instantaneous maximum cell voltage deviation and a historical moving average of the maximum cell voltage deviation.

[0065] In one aspect of the invention, the instantaneous maximum cell voltage deviation is calculated by: identifying the voltage of each cell in an array of the high voltage multi-array battery; identifying a first cell of the array having a maximum voltage of the cells in the array; identifying a second cell of the array having a minimum voltage of the cells in the array; and calculating an average voltage of the array, excluding the first cell and the second cell when calculating the average voltage.

[0066] In one aspect of the invention, calculating the instantaneous maximum battery voltage deviation includes calculating a change in battery voltage increments in an array of the high voltage multi-array battery instead of calculating a derivative of each cell voltage of each cell in each cell array of the high voltage multi-array battery.

[0067] In one aspect of the present invention, a count of instances in which the rate of change of the difference in maximum cell voltage deviations exceeds the predetermined threshold is recorded, and in response to the count exceeding the count threshold, the plug-in charging is suspended and the DTC is recorded.

[0068] In one aspect of the present invention, the method includes: in response to the change rate of the difference in maximum cell voltage deviation of at least one cell array of the high voltage multi-array battery exceeding the predetermined threshold, performing battery power-off of the high voltage multi-array battery.

[0069] In one aspect of the present invention, the method includes: in response to the rate of change of the difference of the maximum cell voltage deviation of at least one cell array of the high voltage multi-array battery exceeding the predetermined threshold, enabling the inhibit restart action of the high voltage multi-array battery for a first duration.

[0070] In one aspect of the present invention, the method includes: in response to the rate of change of the difference in the maximum cell voltage deviation of at least one cell array of the high voltage multi-array battery exceeding the predetermined threshold, monitoring the high voltage multi-array battery for potential thermal events and outputting a notification indicating the need for external thermal monitoring.

[0071] In one aspect of the present invention, monitoring potential thermal events includes monitoring the temperature and temperature change rate of the high voltage multi-array battery, and in response to the temperature exceeding a temperature threshold or the temperature change rate exceeding a temperature change rate threshold, outputting a thermal event notification to a display device and recording a thermal DTC in the memory of the vehicle.

[0072] According to the present invention, a plug-in vehicle is provided, the plug-in vehicle having: a charging port; a high-voltage multi-array battery; a power conversion module, the power conversion module selectively connecting the charging port to the high-voltage multi-array battery; and a battery energy control module (BECM), the BECM including instructions stored in a non-transitory memory, the instructions, when executed, causing the BECM to: calculate a first parameter representing an instantaneous maximum cell voltage deviation of each cell array of the high-voltage multi-array battery; calculate a second parameter representing a rate of change of the first parameter based on a difference between the first parameter and a historical moving average of the first parameter; and in response to the second parameter of at least one cell array of the high-voltage multi-array battery exceeding a predetermined threshold, suspend plug-in charging and record a diagnostic trouble code (DTC) in a memory of the plug-in vehicle.

[0073] According to an embodiment, each array of the high-voltage multi-array battery includes a plurality of cells, and a maximum cell voltage deviation of each array is calculated by calculating a maximum value of a difference between a battery cell voltage of a first cell of the array and an average voltage of battery cells of the array excluding the first cell, a second cell having a maximum voltage, and a third cell having a minimum voltage.

[0074] According to an embodiment, suspending the plug-in charging includes adjusting the power conversion module to stop power supplied by a charger to the charging port from being delivered to the high-voltage multi-array battery.

[0075] According to an embodiment, suspending the plug-in charging and recording the DTC further comprises outputting a notification to a display device, the notification indicating that the plug-in charging has been suspended.

[0076] According to an embodiment, suspending the plug-in charging further comprises adjusting a configuration of the charging port to disconnect a charging connector from the charging port.

[0077] According to an embodiment, suspending the plug-in charging further comprises adjusting a configuration of the charging port to prevent a charging connector from being connected to the charging port for a first duration.

[0078] According to the present invention, a method for operating a multi-array battery pack of a vehicle includes: for each array of the multi-array battery pack, calculating a first parameter representing a change in an instantaneous maximum cell voltage deviation by calculating the maximum value of the difference between the battery cell voltage of a first cell of the array and the average voltage of the remaining cells of the array excluding the first cell, the second cell with the maximum voltage of the array, and the third cell with the minimum voltage of the array; calculating a second parameter representing the difference between the change in the instantaneous maximum cell voltage deviation and the change in the historical moving average cell voltage deviation of the array; in response to the second parameter exceeding a predetermined threshold, adding a value to an integer count; and in response to the integer count exceeding the count threshold, terminating plug-in charging and recording a diagnostic trouble code (DTC) in a memory of the vehicle.

[0079] In one aspect of the invention, the method includes disabling plug-in charging and power output of the multi-array battery pack for a first duration in response to the integer count exceeding the count threshold.

[0080] In one aspect of the invention, the predetermined threshold represents a certain battery cell voltage, above which the temperature of the multi-array battery pack exceeds an operating temperature.

[0081] In one aspect of the present invention, the method includes: in response to the integer count exceeding the count threshold, monitoring the multi-array battery pack for potential thermal events by continuously comparing the temperature of each array of the multi-array battery pack to a temperature threshold, and in response to the temperature exceeding the temperature threshold, discharging the multi-array battery pack, outputting a thermal event notification to a display device, and recording a thermal DTC in the memory of the vehicle.

[0082] In one aspect of the present invention, the method includes: in response to the integer count exceeding the count threshold, monitoring the multi-array battery pack for potential thermal events by continuously comparing the temperature change rate of each array of the multi-array battery pack to a temperature change rate threshold, and in response to the temperature change rate exceeding the temperature change rate threshold, discharging the multi-array battery pack, outputting a thermal event notification to a display device, and recording a thermal DTC in the memory of the vehicle.

Claims

1. A method (400) for detecting battery cell degradation during plug-in charging of a high voltage multi-array battery (120) of a vehicle (100), the method comprising: In response to a rate of change of a difference in maximum cell voltage deviations of at least one cell array of the high voltage multi-array battery exceeding a predetermined threshold, plug-in charging is terminated (420) and a diagnostic trouble code (DTC) is recorded (420) in a memory of the vehicle. 2 . The method according to claim 1 , wherein the rate of change of the difference in the maximum cell voltage deviation is a difference between an instantaneous maximum cell voltage deviation and a historical moving average of the maximum cell voltage deviation.

3. The method according to claim 2, wherein the instantaneous maximum cell voltage deviation is calculated by the following operations: identifying (404) a voltage of each battery cell in an array of the high voltage multi-array battery; identifying (406) a first cell of the array having a maximum voltage among the cells in the array; identifying (406) a second cell of the array having a minimum voltage of the cells in the array; as well as An average voltage of the array is calculated (408), excluding the first battery cell and the second battery cell when calculating the average voltage.

4. The method of claim 2 , wherein calculating the instantaneous maximum battery voltage deviation comprises calculating ( 410 ) a change in battery voltage delta in an array of the high voltage multi-array battery rather than calculating a derivative of each cell voltage of each cell in each cell array of the high voltage multi-array battery.

5. The method of claim 1, wherein a count of instances in which the rate of change of the difference in maximum cell voltage deviations exceeds the predetermined threshold is recorded, and the plug-in charging is suspended and the DTC is recorded in response to the count exceeding a count threshold.

6. The method according to claim 1, further comprising: In response to the rate of change of the difference in maximum cell voltage deviations of at least one cell array of the high voltage multi-array battery exceeding the predetermined threshold, battery power-off of the high voltage multi-array battery is performed.

7. The method according to claim 6, further comprising: In response to the rate of change of the difference in the maximum cell voltage deviations of at least one cell array of the high voltage multi-array battery exceeding the predetermined threshold, enabling a restart inhibit action of the high voltage multi-array battery for a first duration.

8. The method according to claim 1, further comprising: In response to the rate of change of the difference in the maximum cell voltage deviations of at least one cell array of the high voltage multi-array battery exceeding the predetermined threshold, monitoring the high voltage multi-array battery for a potential thermal event and outputting a notification indicating a need for external thermal monitoring.

9. The method of claim 8, wherein monitoring for potential thermal events comprises monitoring a temperature and a rate of temperature change of the high voltage multi-array battery, and in response to the temperature exceeding a temperature threshold or the rate of temperature change exceeding a temperature rate of change threshold, outputting a thermal event notification to a display device and recording a thermal DTC in the memory of the vehicle.

10. A plug-in vehicle (100), comprising: Charging port (134); High voltage multi-array battery (120); a power conversion module (132) that selectively couples the charging port to the high voltage multi-array battery; as well as A battery energy control module (BECM) (150) comprising instructions stored in a non-transitory memory, the instructions when executed causing the BECM to: calculate a first parameter representing an instantaneous maximum cell voltage deviation for each cell array of the high voltage multi-array battery; calculate a second parameter representing a rate of change of the first parameter based on a difference between the first parameter and a historical moving average of the first parameter; and in response to the second parameter of at least one cell array of the high voltage multi-array battery exceeding a predetermined threshold, suspend plug-in charging and record a diagnostic trouble code (DTC) in a memory of the plug-in vehicle.

11. The plug-in vehicle of claim 10, wherein each array of the high voltage multi-array battery includes a plurality of cells, and the maximum cell voltage deviation of each array is calculated by calculating the maximum value of the difference between the battery cell voltage of a first cell of the array and the average voltage of the battery cells of the array excluding the first cell, a second cell having a maximum voltage, and a third cell having a minimum voltage. 12 . The plug-in vehicle of claim 10 , wherein suspending the plug-in charging comprises adjusting the power conversion module to stop power supplied by a charger to the charging port from being delivered to the high voltage multi-array battery. 13 . The plug-in vehicle of claim 10 , wherein suspending the plug-in charging and recording the DTC further comprises outputting a notification to a display device, the notification indicating that the plug-in charging has been suspended.

14. The plug-in vehicle of claim 10, wherein suspending the plug-in charging further comprises adjusting a configuration of the charging port to disconnect a charging connector from the charging port.

15. The plug-in vehicle of claim 10, wherein suspending the plug-in charging further comprises adjusting a configuration of the charge port to prevent a charge connector from being connected to the charge port for a first duration.

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