Intelligent power management system and method for monitoring battery integrity

Abstract

To provide a battery monitoring system for a battery of a battery electric system, including an instruction to determine a degradation level of the battery.SOLUTION: A battery monitoring system (BMS) 15 for a battery of a battery electric system 10 includes a sensor array S1, S2, S3, a processor, and a memory. Execution of the instructions causes the processor to receive battery parameters from the sensor array during respective charging and discharging modes of the battery, the battery parameters including at least a voltage, current and temperature of the battery. Charge-side and discharge-side resistances of the battery are separately determined during charging and discharging modes, followed by calculation of a degradation level of the battery using the charge-side and discharge-side resistances. The processor may also perform a preventive action in response to the degradation level exceeding a calibrated threshold.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 658,673, filed June 11, 2024, which is incorporated herein by reference in its entirety for all purposes. [Background technology]

[0002] Introduction The present disclosure relates to an electrical circuit topology and control method for monitoring the structural integrity of batteries. Electric vehicles, standby power sources, power plants, and other mobile and stationary battery electric systems use rechargeable batteries as energy storage devices. In particular, the rechargeability and high energy storage capacity of lithium-ion batteries have led to widespread adoption of such batteries in numerous industries. For example, lithium-ion batteries are used to power electric motors in mobile and stationary battery electric systems, as well as to provide energy to actuators, sensors, displays, and control circuits in medical devices, industrial systems, and consumer products.

[0003] Lithium-ion batteries are an essential component of battery electrical systems, but their use carries certain potential risks. For example, the internal temperature of an aging or failed battery cell can spike. Therefore, thermal management methods such as coolant / air circulation or heat sinks or cell vents are used to help regulate battery temperature. However, if the temperature of a given battery cell rises beyond a certain point, the materials of the battery and its constituent cells can begin to melt or burn. Pressure buildup within the battery cell can rupture the cell can or outer foil. When this occurs, the cell releases hot gases, molten materials, soot, and other emissions, which can spread to adjacent battery cells. This condition, referred to in the art as thermal runaway, can adversely affect the operation of the battery and the entire battery electrical system. Summary of the Invention

[0004] Disclosed herein is a battery monitoring system and automated method for monitoring rechargeable lithium-ion or other rechargeable batteries in a battery-electrical system. The present teachings seek to protect the battery-electrical system and surrounding surfaces or components from heat damage by detecting potentially dangerous battery degradation conditions before the danger manifests. Thus, the present teachings enable an alert to be issued as advance warning of impending battery failure, providing the operator with sufficient time to then take preventative action, such as battery replacement or circuit disconnection.

[0005] The monitoring strategy contemplated herein determines the internal resistance of a battery while it is in two states: (1) a charge mode in which the battery actively receives charging current, and the internal resistance during such a charge mode is hereinafter referred to as the "charge-side resistance," and (2) a discharge mode in which the battery supplies battery current to a connected load device, and the internal resistance of the battery during such a discharge mode is hereinafter referred to as the "discharge-side resistance." The two internal resistance values ​​are then used to assess the current state of health (SOH) of the battery.

[0006] If a predetermined threshold indicating a potentially dangerous condition of the battery is exceeded, one or more preventative control actions may be implemented to help avoid thermal damage to the battery and / or battery electrical system and its surrounding environment.

[0007] According to a representative embodiment, a battery monitoring system (BMS) includes a sensor array connectable to a battery, a processor, and a non-transitory computer-readable storage medium ("memory"). The memory includes instructions executable by the processor to cause the processor to calculate a charge-side resistance (R1) and a discharge-side resistance (R2) of the battery during a charge mode and a discharge mode, respectively. The processor receives the battery voltage, current, and temperature from the sensor array during the battery charge mode and the battery discharge mode. The charge-side resistance (R1) and the discharge-side resistance (R2) are used to calculate a battery degradation level. Preventive battery action is optionally performed in response to a degradation level exceeding a calibration threshold.

[0008] Also disclosed herein is a method for monitoring a battery in a battery electrical system. One embodiment of the method includes calculating a charge-side resistance (R1) of the battery via an EMU during a charge mode, calculating a discharge-side resistance (R2) of the battery via the EMU during a discharge mode, and then calculating a degradation level of the battery using the charge-side resistance (R1) and the discharge-side resistance (R2). Preventive battery action may also be taken in response to a degradation level exceeding a calibration threshold.

[0009] Also disclosed herein is a battery electrical system. One embodiment of such a system includes a battery connectable to a battery charger during a charging mode, a load device connectable to the battery and thereby energized during a discharging mode, a sensor array connected to the battery, and an electronic monitoring unit (EMU). The EMU is configured to send a measurement request signal to the sensor array and to receive a first set of battery parameters and a second set of battery parameters from the sensor array during the charging mode and the discharging mode in response to the measurement request signal. The battery parameters include at least a voltage, a current, and a temperature of the battery.

[0010] The EMU in this implementation is configured to calculate a charge-side resistance (R1) of the battery during a charge mode using a first battery parameter set, calculate a discharge-side resistance (R2) of the battery during a discharge mode using a second battery parameter set, and calculate a degradation level of the battery using the charge-side resistance (R1) and the discharge-side resistance (R2). The EMU then performs preventative battery action in response to the degradation level exceeding a calibrated threshold.

[0011] The above summary is not intended to represent every embodiment or aspect of the present disclosure. Rather, the foregoing summary illustrates certain novel aspects and features described herein. These and other features and advantages of the present disclosure will be readily apparent from the following detailed description of exemplary embodiments and aspects for carrying out the disclosure, taken in conjunction with the accompanying drawings and the appended claims. [Brief explanation of the drawings]

[0012] The drawings described herein are for purposes of illustration only, are schematic in nature, and are intended to be exemplary rather than limiting the scope of the present disclosure. [Figure 1] 1 illustrates a battery electrical system having a rechargeable battery and a battery monitoring system (BMS) constructed in accordance with the present disclosure. [Figure 2A] 2 illustrates a representative embodiment of the battery shown in FIG. 1 for various levels of capacity. [Figure 2B] 2 illustrates a representative embodiment of the battery shown in FIG. 1 for various levels of capacity. [Figure 2C] 2 illustrates a representative embodiment of the battery shown in FIG. 1 for various levels of capacity. [Figure 3A] The figures show representative battery models in a new state and a degraded state, respectively. [Figure 3B] The figures show representative battery models in a new state and a degraded state, respectively. [Figure 4]2 is a schematic circuit diagram of the BMS of FIG. 1 according to one possible embodiment. [Figure 5] The graph shows varying capacity-based cell voltage, with voltage on the vertical axis and state of charge (SOC) / remaining capacity (%) on the horizontal axis. [Figure 6] The change in internal resistance based on the state of charge (SOC) is shown, with capacity or SOC (%) shown on the horizontal axis and ohmic resistance on the vertical axis. [Figure 7] 2 is a flow chart illustrating a method for monitoring the battery of the battery electrical system of FIG. 1.

[0013] The present disclosure may be modified or embodied in alternative forms, representative embodiments of which are shown in the drawings and described in detail below. The inventive aspects of the present disclosure are not limited to the disclosed embodiments. Rather, the present disclosure is intended to encompass alternative forms that fall within the scope of the present disclosure as defined by the appended claims. DETAILED DESCRIPTION OF THE INVENTION

[0014] Referring to the drawings, wherein like reference numerals refer to the same or similar components throughout the several views, a battery electrical system 10 is shown generally in FIG. 1. In a simplified embodiment, the battery electrical system 10 includes a rechargeable battery 12, an electrical switch 14, and a load device (L A ) 11 and a battery monitoring system (BMS) 15. BMS 15, in turn, includes a sensor array 16 and an electronic monitoring unit (EMU) 18, where sensor array 16 is connectable to battery 12, for example, via wired transmission conductors and / or wireless connections.

[0015] An EMU 18 as contemplated herein includes a processor (P) 19 and a non-transitory computer-readable storage medium ("memory") (M) 20. The memory 20 includes instructions stored thereon and executable by the processor 19 that cause the EMU 18 to perform a method 50, a non-limiting example of which is described below with reference to FIG. 7. Among other operations, the EMU 18 initiates this process by sending a measurement request signal (CC R ) to send.

[0016] 1 is described below as a lithium-ion (Li) battery for consistency, but may alternatively be configured in other embodiments as another rechargeable battery, such as lithium metal oxide (LMO), lithium metal, nickel-metal hydride (NiMH), nickel-cadmium (NiCd), or another application-specific battery chemistry. In various implementations, the battery electrical system 10 may be used as part of a mobile or stationary battery-powered device. For example, as shown in FIG. 1, the battery 12 may be used to power a portable electronic device such as a computer 21A, e.g., a tablet, desktop, or laptop computer, or a mobile phone 21B.

[0017] In other applications, battery 12 can be used, for example, as part of a handheld surgical instrument 21C, or a wearable device 21D, such as a continuous glucose monitor (CGM) as shown, or a medical device, such as an automatic external defibrillator (AED), a blood oxygen monitor, or an infusion pump. Similarly, battery 12 can be used to power a mobile system 21E, such as an electric vehicle. Still other applications can be readily envisioned, including, but not limited to, electronic gaming systems, control consoles, or other industrial, medical, or transportation systems. Accordingly, the exemplary uses, chemistries, structures, and simplified depictions of battery 12 herein are illustrative of, and not limiting of, the present teachings, unless otherwise specified.

[0018] In different embodiments, the BMS 15 of FIG. 1 may include other components. For example, a direct current-to-direct current (DC-DC) converter 22 may be used with the battery 12 to increase or decrease the battery voltage before providing energy to the load device 11. A battery charger 13 may be connectable to the battery 12 to recharge it as needed. In an alternating current (AC) configuration of the battery electrical system 10, the battery 12 may be connected to a DC-to-AC inverter circuit 23, which converts the voltage of the battery 12 to a DC-to-AC inverter voltage. The inverter circuit 23 converts the voltage of the battery 12 to a DC-to-AC inverter voltage. B ) 111. Depending on the application, the loads 11 and 111 may be variously embodied as electric motors, rotary actuators, linear actuators, displays, transducers, and / or other electric or electromechanical devices.

[0019] As part of this strategy, various sensors S1, S2, ..., SN of sensor array 16 are used to measure or sense battery parameters during charging and discharging modes of battery 12. The battery parameters used as part of method 50 (FIG. 7) include at least the voltage, current, and temperature of battery 12, and EMU 18 is also configured to determine the state of charge (SOC) and open-circuit voltage (OCV) of battery 12, as well as its current charge / discharge state.

[0020] As part of the contemplated approach, the input signal (CC IN ) are communicated to the EMU 18. The EMU 18 then communicates electronic control signals (CC) to a remote device 24, such as a graphical user interface (GUI) as shown, a display screen, and / or the disconnect switch 14. OUT ) The disconnect switch 14 may be embodied as an electromechanical contactor or relay, such as a solid state relay (SSR), operable to disconnect the battery 12 under certain fault conditions. Although omitted from FIG. 1 for simplicity and clarity, the battery electrical system 10 may include a thermal management system, such as those summarized above, such as cooling plates, fins, heat sinks, coolant conduits, etc., to help regulate the temperature of the battery 12 during normal operation. Similarly, other circuit components, such as fuses, may be implemented to ensure the safety and reliability of the battery electrical system 10 during operation.

[0021] Referring now to FIGS. 2A, 2B, and 2C, which collectively illustrate the battery 12 of FIG. 1 at various levels of charge depletion, the present teachings proceed with the understanding that the internal resistance of a typical battery 12 tends to increase over time due to aging and other degradation. FIG. 2A illustrates a new / properly functioning battery 12 with 100% usable nominal usable capacity 26 and internal resistance (R). FIGS. 2B and 2C illustrate the aging and degradation of the battery 12 when the usable capacity 26 is 75% and 50%, respectively. Relative to the new battery 12 of FIG. 2A, the internal resistance of the battery 12 of FIG. 2B has increased to (4 / 3)R in this illustrative example. As aging continues, the internal resistance (R) continues to increase, and in this illustrative case may continue to increase to twice the level of FIG. 2A, i.e., 2R. In other words, aging of the battery 12 results in a significant increase in its internal resistance.

[0022] 3A and 3B, a bifurcation model 28 is used herein as part of this strategy. That is, the internal resistance (R) of battery 12, described above with reference to FIGS. 2A-2C, is now divided into two respective components: (1) a charge-side resistance (R1) and (2) a discharge-side resistance (R2). As described above, R1 and R2 represent the internal resistance of battery 12 determined during the charge and discharge modes of battery 12, respectively. As shown in FIG. 3A, for a new / properly functioning battery 12, the charge-side resistance and the discharge-side resistance are equal, i.e., R1 = R2. Furthermore, for each of the charge-side internal resistance R1 and the discharge-side internal resistance R2, the rate of increase in internal resistance is approximately the same as the battery 12 ages under normal use conditions.

[0023] However, as shown in FIG. 3B, for a damaged battery, this “side-by-side” relationship between R1 and R2 changes such that the charge-side resistance (R1) exceeds the discharge-side resistance (R2), i.e., R1 > R2. As the battery 12 continues to degrade toward a potentially dangerous condition, an ever-widening difference emerges between the respective charge-side resistance R1 and discharge-side resistance R2. This degradation trajectory is closely monitored by the BMS 15 of FIG. 1 as described herein, thereby enabling the BMS 15 and its resident EMU 18 to proactively take preventative measures in protecting the battery 12, the battery electrical system 10, and the surrounding environment from potential thermal damage.

[0024] R1 and R2: During battery charging operations in a typical lithium-ion configuration of battery 12, lithium ions migrate within battery 12 and are occluded on the electrode surfaces in a stable manner. However, abnormal growth and formation of unstable lithium deposits can result from repeated charging cycles or increased charging rates, for example, during rapid DC charging of the battery. Agglomerations of deposits can form elongated, branched structures called dendrites. Dendrites and other lithium accumulations increase the charge-side resistance.

[0025] The formation of dendrites in lithium-ion battery cells is more pronounced compared to similar buildup during discharge. While the discharge process also increases internal resistance, the buildup of lithium deposits on the electrode surfaces during the discharge mode tends to be less abnormal. This results in a smaller rate of increase in the discharge-side resistance (R2) than in the charge-side resistance (R1). Therefore, the absolute difference between the values ​​R1 and R2 and / or their respective rates of change are monitored and tracked by the EMU 18 of FIG. 1 to ascertain the state of health (SOH) of the battery 12 and, if necessary, take one or more protective or preventative actions to protect the battery 12 and / or the battery electrical system 10 from thermal damage.

[0026] Referring to FIG. 4 , the battery electrical system 10 is shown schematically as a BMS 15 and a load device 11. During charging mode, the battery 12 is disconnected from the load device 11 via a disconnect switch 14. A charging switch (SW1) 30 is commanded to close, for example, by the EMU 18 or another charge controller connecting the battery 12 to the battery charger 13. As understood in the art, the battery charger 13 may be connected to an external power source (not shown). If the power source is an AC outlet, the battery charger 13 includes an AC-DC converter to convert, filter, and output appropriate DC voltage and current waveforms to charge the battery 12. The current sensor (S1), part of the sensor array 16 in FIG. 1 described above, may be used to detect the direction of current flow, thus helping to determine whether the battery 12 is in charging mode or discharging mode. If the battery 12 is removed from the battery charger 13 while in use (discharging mode), the charging switch 30 automatically opens when the battery 12 is removed from the battery charger 13.

[0027] In possible implementations of EMU 18, corresponding hardware and software modules or blocks may be implemented to perform the necessary processing functions of method 50 (FIG. 7). State of Charge (SOC) block 33 may be used to determine the current SOC of battery 12. SOC block 33 may be implemented in a variety of ways, including, but not limited to, coulomb counting. In such an approach, current flowing into and out of battery 12 over time is tracked and integrated to determine the amount of charge transferred. Other approaches may include, for example, machine learning, voltage and temperature-based lookup tables, temperature-specific OCV-SOC tables or curves, or other possible approaches.

[0028] The EMU 18 may also include a voltage measurement block 35. This feature may be implemented using voltage sensor S2 of the sensor array 16 (FIG. 1), where the measured voltage is periodically measured, communicated to voltage measurement block 35, and stored in a non-volatile portion of memory 20. An internal resistance calculation block 37 may be used to calculate charge-side resistance R1 and discharge-side resistance R2 as part of method 50 of FIG. 7 using data from blocks 33 and 35, as described below, along with measured current values ​​from a current measurement block 39. A current sensor (S1) similarly measures current and communicates the measured current value (IDD) to the internal resistance calculation block 37 and a charge / discharge detection block 40 to determine when the battery 12 is charging or discharging. As mentioned above, this may be accomplished by detecting the direction of current flow through the battery 12, which may normally be unidirectional due to the presence of diodes D1 and D2, when properly configured and functioning.

[0029] The EMU 18 also considered battery temperature when assessing the SOH of the battery 12. To that end, the EMU 18 includes a temperature measurement block 42 in communication with a temperature sensor S3, such as a thermistor or thermocouple. The measured battery temperature (T B ) can be requested, communicated and recorded by the temperature measurement block 42, possibly with the assistance of an analog-to-digital converter (ADC) 43. The measured battery temperature (T B ) is communicated to a battery status block 44 which is operable to determine the aging state, and specifically the level of aging, of the battery 12. This function is performed using the reported charge-side resistance R1 and discharge-side resistance R2.

[0030] As will be explained below, an alert is generated by the EMU 18 when the charging-side resistance R1 and the discharging-side resistance R2 are high compared to a threshold value. OUT), for example, to the GUI 24 or another external audio and / or visual device. Depending on the application, the alert may involve an audible alarm, an indicator light, a text message, etc., and may include a request to discard or replace the battery 12. If the EMU 18 determines that battery 12 failure is imminent, the EMU 18 may take other preventative measures, such as disconnecting the load device 11 or preventing charging via the battery charger 13. Such action may help prevent thermal damage to the surrounding environment or, in the case of a wearable version of the battery electrical system 10, to the user of the wearable device.

[0031] Relevant parameters of the battery 12 that can be used as part of the method 50 of FIG. 7 are described with reference to FIGS. 5 and 6. FIG. 5 is a voltage plot 55 of battery voltage in millivolts (mV) versus remaining capacity of the battery 12, where remaining capacity is expressed as a percentage (%) of SOC. Traces 56 and 156 represent the battery voltage during charging and discharging modes of the battery 12, respectively, for a given temperature. Thus, movement between traces 56 and 156 represents the voltage difference (ΔV) relative to a baseline, i.e., the open circuit voltage (OCV). For a given temperature and capacity, the OCV therefore serves as a stable reference from which the voltage difference (ΔV) can be determined as part of the method 50. As understood in the art, the OCV from a temperature-specific lookup table referenced or indexed by the SOC and OCV can be used, for example, to determine the voltage difference (ΔV) as shown. That is, ΔV is the difference between the measured battery voltage and the OCV, i.e., ΔV=V M -OCV.

[0032] 6 shows, via trace 60, that the internal resistance of battery 12 increases with the state of charge (SOC) of battery 12. This resistance, expressed in ohms (Ω), is temperature specific. For example, trace 61 shows -10° C. Similarly, traces 62, 63, 64, and 65 represent the resistance vs. SOC of a typical battery 12 at 0° C. and 10° C., respectively. + 10℃, + 25°C, and + 1 represents the relationship between resistance and SOC at 60° C. Thus, the coldest battery 12 in this example range has the highest internal resistance at a given SOC. Therefore, the present teachings may rely on one or more temperature-specific lookup tables, such as SOC and OCV of the battery 12, as part of the operation of the EMU 18.

[0033] 7, method 50 is described as a series of steps or logic blocks, each of which may be embodied as computer-readable instructions. Such instructions may be stored in memory 20 of EMU 18 of FIG. 1 or in another accessible non-volatile, non-transitory memory location and executed by processor 19 to cause EMU 18 to perform the functions described above.

[0034] 1, execution of instructions embodying method 50 of FIG. 7 involves the cooperative use of processor 19, memory 20, and sensor array 16 when assessing the SOH of battery 12. The functions of method 50, described in detail below, are embodied as computer-readable instructions and executed from memory 20, e.g., magnetic or optical media, CD-ROM, and / or solid-state / semiconductor memory (e.g., various types of RAM or ROM). Processor 19 may encompass one or more control modules, control units, microprocessor chips, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), electronic circuits, or central processing units. Examples of associated memory components of memory 20 include read-only memory, programmable read-only memory, and non-transitory computer-readable storage devices such as hard drives. As used herein, the temporary components of memory 20 may store machine-readable instructions in the form of one or more software or firmware programs or routines, combinatorial logic circuits, input / output circuits and devices, signal conditioning and buffering circuits, and other components that may be accessed by one or more processors 19 to provide the functionality described above.

[0035] Generally, execution of such instructions from memory 20 is initiated by a measurement request signal (CC R ) and its transmission to sensor array 16. This then causes processor 19, and therefore EMU 18, to receive a first set of battery parameters from sensor array 16 during a charging event or mode of battery 12. It also causes processor 19 to receive a second set of battery parameters from sensor array 16 during a discharging mode of battery 12. The first and second battery parameter sets are coupled to an input signal (CC IN ), and includes at least the voltage, current, and temperature of the battery 12.

[0036] Once the battery parameters are communicated and received, processor 19 calculates the charge-side resistance (R1) of battery 12 during charge mode using a first set of battery parameters. Processor 19 also calculates the discharge-side resistance (R2) of battery 12 during discharge mode using a second set of battery parameters. Processor 19 then uses charge-side resistance (R1) and discharge-side resistance (R2) to calculate the aging or degradation level of battery 12, and then performs protective action in response to the degradation level exceeding a calibrated threshold.

[0037] An exemplary embodiment of method 50 is shown in FIG. 7. Beginning at block B52 (“SOC, T”), EMU 18 determines the SOC and temperature of battery 12. The SOC may be determined using, for example, coulomb counting, machine learning, a voltage and temperature-based lookup table, an OCV-SOC curve, or other possible techniques described above, via SOC block 33 of FIG. 3. Temperature measurement block 42, described above with reference to FIG. 3, may be used to ascertain the temperature of battery 12. After recording the SOC and corresponding temperature in a non-volatile component of memory 20, method 50 proceeds to block B54.

[0038] Block B54 ("IDD-1") involves measuring the battery current via current sensor (S1) of Figure 3. As with block B52, the measurement is recorded in a non-volatile component of memory 20. Method 50 then proceeds to block B56.

[0039] In block B56 ("Charge / Discharge?"), EMU 18 determines whether battery 12 is in a charge mode or a discharge mode. For example, EMU 18 can determine the direction of current flow of the measured current from block B54 and other information, such as the state of charge switch 30 in FIG. 3, to determine whether battery 12 is actively charging or discharging. Method 50 then proceeds to block B58 if EMU 18 determines battery 12 is in a charge mode, or to block B57 if EMU 18 determines battery 12 is in a discharge mode.

[0040] Block B57 in Figure 7 ("OCV D @SOC X In block B50, the method 50 next obtains the current SOC, i.e., SOC X Open circuit voltage (OCV) during charging mode C ) is determined. As shown in plot 55 of FIG. 5, OCV is specific to a given SOC. As understood in the art, OCV also increases with decreasing temperature (and vice versa). Therefore, block B58 determines the temperature measurement made in block B52. Method 50 then proceeds to block B59.

[0041] Block B58 (OCV D @SOC X Block B58 obtains the open circuit voltage (OCV) during the charging mode for the battery 12 relative to the current SOC from block B52. C ) As shown in plot 55 of FIG. 5, OCV is specific to a given SOC. As understood in the art, OCV also increases with decreasing temperature (and vice versa). Therefore, block B58 is determined from the temperature measurement made in block B52. Method 50 then proceeds to block B60.

[0042] Blocks B59 and B60 ("V2" and "V1", respectively) involve measuring the voltage of battery 12 via voltage sensor (S2) of Figure 3. This value is then recorded in a non-volatile component of memory 20. Method 50 then proceeds to block B61 (from block B59) or B62 (from block B60).

[0043] Block B61 ("R2@SOC X ") is executed during the discharge mode of the battery 12 to calculate the discharge-side resistance (R2). Similar to block B62 described below, the method 50 proceeds to block B64 once the discharge-side resistance (R2) has been determined and stored in non-volatile memory.

[0044] Block B62 ("R1@SOC X "), the EMU 18 then calculates the charge-side resistance (R1) at the current SOC from block B52, i.e., the temperature-specific SOC X For simplicity, we use ohmic resistance and calculate R1 as

[0045]

number

[0046] 7, block B64 ("Health Check") involves performing a health check of battery 12 via EMU 18 using the recorded values ​​of charge-side resistance (R1) and discharge-side resistance (R2) from blocks B62 and B61, respectively, as described above. Block B64 may be implemented in a variety of ways depending on the application. For example, instructions embodying method 50 may be executable by processor 19 of FIG. 1 to cause EMU 18 to calculate a level of deterioration, or equivalently, a state of health (SOH), of battery 12 as a function of resistances R1 and R2.

[0047] One possible approach is to evaluate the absolute difference between the charge-side resistance (R1) and the discharge-side resistance (R2). As mentioned above, these values ​​are equal when the battery 12 is new, i.e., R1 = R2, as shown in FIG. 3A. However, an aging / deteriorating battery 12 experiences an ever-increasing internal resistance difference, as the charge-side resistance (R1) increases faster than the discharge-side resistance (R2), as shown in FIG. 3B. Therefore, a possible strategy, implementable by the EMU 18, is to compare the charge-side resistance (R1) with the discharge-side resistance (R2) to ascertain the magnitude of the difference. The magnitude of this difference can be used as a degradation level.

[0048] Alternatively, EMU 18 may track the values ​​of charge-side resistance (R1) and discharge-side resistance (R2) over time, calculate the rate of change of each, and then compare the rates of change to determine the difference, or delta, between them. In this case, instructions embodying method 50 are executable by processor 19 to cause EMU 18 to calculate the ratio of (i) the rate of increase of charge-side resistance to (ii) the rate of increase of discharge-side resistance. This calculated ratio may be used as the health level in one or more embodiments. Method 50 proceeds to block B66 once EMU 18 has determined the health level of battery 12.

[0049] In block B66 ("Battery SOH=OK?"), the EMU 18 then uses the above-mentioned degradation levels to determine whether the current operating condition of the battery 12 is healthy enough for continued use without intervention. For example, a lookup table may be populated with an incremental multiple of, or a value based on, the discharge-side resistance (R2), and the EMU 18 compares the charge-side resistance (R1) or a value based thereon to a threshold value.

[0050] Using this simplified example, where the degradation level is the magnitude of the absolute difference between R1 and R2, i.e., |R1-R2|, the look-up table in memory 20 of EMU 18 may be populated with thresholds, e.g., 1.5R2, 2R2, 3R2, 4R2, etc. If the rate of change of the charge-side resistance (R1) and discharge-side resistance (R2) is used, similar graduated thresholds may be used, e.g.,

[0051]

number

[0052] In block B68 ("Preventive Action"), each threshold considered in block B66 is associated with a specific preventive control action. "Preventive" as contemplated herein refers to an action that notifies a user of the battery electrical system 10 of FIG. 1 that the battery 12 is degrading in some way. If the battery 12 is only mildly degraded, the preventive action may take a less urgent tone or mechanism, typically without the EMU 18 intervening in the operation of the battery 12. However, as the degradation level becomes more pronounced, the EMU 18 may escalate the preventive action response in terms of its urgency, potentially intervening in the control of the battery 12 itself.

[0053] The communications within block B68 may include sending an electronic alert signal to a remote device, such as GUI 14 of FIG. 1. Various levels of alert or warning messages may be communicated in this manner.

[0054]

number

[0055]

number

[0056] Using an exemplary embodiment, an SMS text message, e.g., "Battery Near End of Life - Inspection Recommended," may be sent to the GUI 24, recommending replacement or inspection of the battery 12 within an extended time frame or without expressing urgency. If the battery electrical system 10 of FIG. 1 is so equipped, a light or lamp may be illuminated in a corresponding color, such as amber or yellow, to visually alert the user that the battery 12 is in a partially degraded but still functional state. The urgency of the alert / messaging may similarly increase if the charge-side resistance becomes much greater than the discharge-side resistance, such as during the representative condition "R1 = 3R2." For example, the example text above could be replaced with a more urgent phrase, such as "Battery Condition Poor - Inspect Immediately Recommended." In this example, the optional light could be illuminated in a commonly understood color, such as red, and / or could pulse or flash in a distinguishable manner to heighten the alert state. Similarly, an audible warning sound could be sounded to draw the user's attention to the possible, impending failure of the battery 12.

[0057] At some point, EMU 18 may determine that continued use of battery 12 is potentially harmful to the health and safety of battery electrical system 10 and its potential users. In this case, EMU 18 may take protective action by commanding disconnect switch 14 ( FIG. 1 ) to open, thereby disconnecting battery 12 from load device 11. Opening disconnect switch 14 effectively removes battery 12 from the DC voltage bus connecting battery 12 to load device 11, thus protecting load device 11 from draining power from the disconnected battery 12. Similarly, EMU 18 may prevent charge switch 30 from closing to prevent charging operation, for example, by sending an override or bypass signal to battery charger 13 and / or the control logic of charge switch 30. Thus, battery 12 is isolated from both the charge and discharge sides of battery electrical system 10.

[0058] Using method 50 or embodiments thereof, lithium-ion and other high-energy batteries can be safely managed in a number of beneficial applications. The solutions presented herein enable early detection of potentially dangerous conditions in such batteries by separately assessing internal resistance during charging and discharging and by monitoring the changing relationship between such internal resistance values ​​over time. The level of degradation can be expressed as a numerical value of SOH, with, for example, an SOH of "1" corresponding to a perfectly healthy battery and an SOH of "0" corresponding to a completely degraded / inoperable battery. Values ​​between the normalized extremes of this exemplary range can correspond to progressively degraded states of a battery, such as battery 12 described herein, with SOH values ​​closer to 0 being more degraded than values ​​closer to an SOH value of 1. These and other advantages of the present teachings will be readily apparent to those skilled in the art having the benefit of the foregoing disclosure.

[0059] The following clauses provide further exemplary configurations of the solutions disclosed herein. Clause 1: A BMS as described above for a battery in a battery electrical system, comprising: a sensor array connectable to the battery; a processor; and a non-transitory computer-readable storage medium ("memory"), the memory including instructions executable by the processor to cause the processor to receive the battery's voltage, current, and temperature from the sensor array during a battery charging mode and during a battery discharging mode, calculate the battery's charge-side resistance (R1) using the battery's voltage, current, and temperature during the charging mode, calculate the battery's discharge-side resistance (R2) using the battery's voltage, current, and temperature during the discharging mode, and determine the battery's degradation level using the charge-side resistance (R1) and the discharge-side resistance (R2). Clause 2: The BMS of clause 1, wherein the instructions are executable by the processor and cause the processor to perform preventative battery action in response to a degradation level of the battery exceeding a calibration threshold. Clause 3: The BMS of clause 1 or 2, wherein the instructions are executable by a processor and cause the processor to calculate a degradation level of the battery as the difference between the charge-side resistance and the discharge-side resistance. Clause 4: The BMS of any one of clauses 1 to 3, wherein the instructions are executable by a processor and cause the processor to calculate a ratio of (i) the rate of increase in charge-side resistance to (ii) the rate of increase in discharge-side resistance as a calculated ratio, and the degradation level comprises the calculated ratio. Clause 5: A BMS described in any one of clauses 1 to 4, wherein the instructions are executable by the processor to cause the processor to determine the battery's state of charge (SOC) and the battery's open circuit voltage (OCV) at a given battery temperature, and the instructions are executable by the processor to cause the processor to calculate a degradation level using the battery's SOC and OCV. Clause 6: The BMS of clause 5, wherein the instructions are executable by the processor and cause the processor to access temperature specific lookup tables such as a battery SOC and a battery OCV. Clause 7: A BMS as described in any one of clauses 1 to 6, wherein the instructions are executable by a processor and cause the processor to transmit an electronic alert signal to a remote device. Clause 8: The BMS of clause 7, wherein the battery is connectable to the load device via a disconnect switch in the battery electrical system, and the instructions are executable by the processor to instruct the processor to open the disconnect switch, thereby disconnecting the battery from the load device. Clause 9: A method for monitoring a battery in a battery electrical system, the method including: receiving a first battery parameter set from a sensor array via a processor during a charging mode of the battery; receiving a second battery parameter set from the sensor array via a processor during a discharging mode of the battery; calculating a charge side resistance (R1) of the battery via the processor during the charging mode using the first battery parameter set; calculating a discharge side resistance (R2) of the battery via the processor during the discharging mode using the second battery parameter set; and calculating a deterioration level of the battery using the charge side resistance (R1) and the discharge side resistance (R2), wherein the first battery parameter set and the second battery parameter set include at least a voltage, a current, and a temperature of the battery. Clause 10: The method of clause 9, wherein calculating the degradation level of the battery includes calculating a difference between a charge-side resistance and a discharge-side resistance. Clause 11: The method of clause 9 or 10, wherein calculating the battery degradation level includes calculating the ratio of (i) the rate of increase in charge side resistance to (ii) the rate of increase in discharge side resistance as a calculated ratio, and the degradation level includes the calculated ratio. Clause 12: A method according to any one of clauses 9 to 11, wherein calculating the deterioration level of the battery includes determining the state of charge (SOC) of the battery at a given battery temperature and calculating the deterioration level using the SOC. Clause 13: The method of clause 12, further comprising accessing a lookup table indexed by the battery SOC and the battery temperature. Clause 14: The method of any one of clauses 9 to 13, further comprising performing a battery protective action, such as sending an electronic alert signal to a remote device, in response to the degradation level exceeding a calibration threshold. Clause 15: The method of clause 14, wherein the battery is connectable to a load device via a disconnect switch in the battery electrical system, and performing a protective action includes instructing the disconnect switch to open, thereby disconnecting the battery from the load device. Clause 16: A battery electrical system comprising: a battery connectable to a battery charger during a charging mode; a load device connectable to the battery and energized thereby during a discharging mode; a sensor array connected to the battery; and an electronic monitoring unit (EMU) having a processor and a non-transitory computer-readable storage medium ("memory"), the memory comprising instructions executable by the processor to cause the EMU to: send a measurement request signal to the sensor array; receive a first battery parameter set from the sensor array in response to the measurement request signal during the charging mode; and receive a first battery parameter set from the sensor array in response to the measurement request signal during the discharging mode of the battery. receiving a second battery parameter set from the battery; calculating a charge-side resistance (R1) of the battery during a charge mode using the first battery parameter set; calculating a charge-side resistance (R2) of the battery during a discharge mode using the second battery parameter set; calculating a degradation level of the battery using the charge-side resistance (R1) and the discharge-side resistance (R2); and performing preventive action on the battery in response to the degradation level exceeding a calibration threshold, wherein the first battery parameter set and the second battery parameter set include at least a voltage, a current, and a temperature of the battery. Clause 17: The battery electrical system of clause 16, wherein the instructions are executable by the processor to cause the EMU to calculate a degradation level of the battery as the difference between the charge-side resistance and the discharge-side resistance. Clause 18: A battery as described in clause 16 or 17, wherein the instructions are executable by a processor and cause the EMU to calculate a ratio of (i) the rate of increase in charge side resistance to (ii) the rate of increase in discharge side resistance as a calculated ratio, and the deterioration level includes the calculated ratio. Clause 19: A battery electrical system as described in any one of clauses 16 to 18, wherein the EMU includes a SOC calculation block operable to determine the battery's state of charge (SOC) and open circuit voltage (OCV) at a given battery temperature, and the instructions are executable by the processor to cause the EMU to calculate a degradation level using the battery's SOC and OCV, and the instructions are executable by the processor to cause the EMU to access a temperature-specific lookup table indexed by the battery's SOC and OCV. Clause 20: A battery electrical system as described in any one of clauses 16 to 19, wherein the battery is connectable to a load device via a disconnect switch, and the instructions are executable by the processor to cause the EMU to perform a protective action by instructing the EMU to open the disconnect switch, thereby disconnecting the battery from the load device.

[0060] While several modes for carrying out many aspects of the present teachings have been described in detail, those skilled in the art to which these teachings pertain will recognize various alternative ways of implementing the present teachings that fall within the scope of the appended claims. The above description and accompanying drawings are illustrative and exemplary of the entire range of alternative embodiments that those skilled in the art will recognize as structurally and / or functionally equivalent based on the content contained therein, or as implied by what is otherwise revealed, and are not limited to only the embodiments explicitly shown and / or described. Moreover, the concepts expressly include combinations and subcombinations of the described elements and features. The Detailed Description and drawings supplement and explain the present teachings, the scope of which is defined solely by the claims.

Claims

1. 1. A battery monitoring system (BMS) for a battery in a battery electric system, comprising: a sensor array connectable to the battery; a processor; a non-transitory computer-readable storage medium ("memory"), the memory executable by the processor, the processor receiving a voltage, a current, and a temperature of the battery from the sensor array during a charging mode of the battery and during a discharging mode of the battery; calculating a charge-side resistance (R1) of the battery using the voltage, the current, and the temperature of the battery during the charging mode; calculating a discharge-side resistance (R2) of the battery using the voltage, the current, and the temperature of the battery during the discharge mode; A battery monitoring system (BMS) for a battery in a battery electrical system, comprising instructions for determining a deterioration level of the battery using the charge-side resistor (R1) and the discharge-side resistor (R2).

2. 2. The BMS of claim 1, wherein the instructions are executable by the processor to cause the processor to perform preventative action on the battery in response to the level of deterioration of the battery exceeding a calibrated threshold.

3. 2. The BMS of claim 1, wherein the instructions are executable by the processor to cause the processor to calculate the level of degradation of the battery as a difference between the charge-side resistance and the discharge-side resistance.

4. 2. The BMS of claim 1, wherein the instructions are executable by the processor and cause the processor to calculate a ratio of (i) a rate of increase of the charge-side resistance to (ii) a rate of increase of the discharge-side resistance as a calculated ratio, and wherein the degradation level comprises the calculated ratio.

5. 2. The BMS of claim 1, wherein the instructions are executable by the processor to cause the processor to determine a state of charge (SOC) of the battery and an open circuit voltage (OCV) of the battery at a given temperature of the battery, and the instructions are executable by the processor to cause the processor to calculate the degradation level using the SOC and the OCV of the battery.

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