Dynamic target state of charge for hybrid vehicle capacity estimation
By depleting and recharging the battery in a hybrid vehicle, measuring the stand-alone charging state, and calculating the battery capacity in combination with accumulated charge, the problem of difficult to determine the battery charging state and health status in the prior art is solved, and the accurate evaluation and diagnosis of the battery status is achieved.
Patent Information
- Application Number
- CN202411123037.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-09-05
- Filing Date
- 2024-08-15
- Publication Date
- 2025-03-07
AI Technical Summary
The prior art is difficult to effectively determine the charging status and health status of batteries in hybrid vehicles, and there is a lack of direct methods to understand the charging status of batteries.
By depleting and recharging the battery during vehicle operation, the target low charge state and high charge state are reached, and the stand-half low charge state and stand-half high charge state are measured after standing, and the accumulated charge is calculated.
Accurate assessment of the battery charge status and health status of hybrid vehicles is achieved, providing the ability to diagnose and monitor battery operation.
Smart Images
Figure CN119567948A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to determining the health of a battery used in a hybrid vehicle, and in particular, to systems and methods for determining the charge capacity of a battery. Background Art
[0002] The battery is an important component of a motor vehicle. For a hybrid vehicle, the battery is relied upon to power the vehicle when in electric mode, and to provide ignition in the internal combustion engine when in combustion mode. Knowing the health of the battery is an important consideration for keeping the vehicle in operating condition. Since the battery can be depleted or charged, depending on the operating mode of the vehicle, there is no direct way to know the state of charge or health of the battery. Therefore, it is desirable to provide a method for determining the state of charge of a battery used in a hybrid vehicle. Summary of the invention
[0003] In one exemplary embodiment, a method of calculating a battery capacity of a vehicle is disclosed. During operation of the vehicle, a battery is depleted to reach a target low state of charge. After the battery reaches the target low state of charge, the battery rests for a first rest period. A rest low state of charge is determined after the first rest period. During operation of the vehicle, the battery is charged to reach a target high state of charge. After the battery reaches the target high state of charge, the battery rests for a second rest period. A rest high state of charge is determined after the second rest period. A capacity of the battery is calculated based on the rest low state of charge and the rest high state of charge.
[0004] In addition to one or more of the features described herein, the method also includes measuring a cumulative charge on the battery while charging the battery, and calculating a capacity of the battery based on the resting low state of charge, the resting high state of charge, and the cumulative charge.
[0005] In addition to one or more of the features described herein, the target low state of charge is at a low end of an operating range (working range) of the battery and the target high state of charge is at a high end of the operating range.
[0006] In addition to one or more features described herein, the method includes at least one of: measuring a first voltage of the battery after the first rest period and determining the resting low state of charge based on the first voltage, and measuring a second voltage of the battery after the second rest period and determining the resting high state of charge based on the second voltage.
[0007] In addition to one or more of the features described herein, determining at least one of a resting low state of charge and a resting high state of charge further comprises one of using a lookup table relating state of charge to voltage and using a model equation relating state of charge to voltage.
[0008] In addition to one or more features described herein, the method also includes estimating the capacity of the battery based on at least one of: the time since the previous update is greater than a selected time criterion, the mileage since the previous update is greater than a selected mileage criterion, and the variance of the values in the previous update is greater than a variance criterion.
[0009] In addition to one or more of the features described herein, the method includes at least one of: running a diagnostic test on the battery based on the estimated capacity, calculating a state of charge of the battery based on the estimated capacity, and sending a signal indicative of a state of health of the battery.
[0010] In another exemplary embodiment, a system for calculating a battery capacity of a vehicle is disclosed. The system includes a processor configured to operate the vehicle to deplete the battery to reach a target low state of charge, measure the resting low state of charge after allowing the battery to rest for a first rest period after the battery reaches the target low state of charge, operate the vehicle to charge the battery to reach a target high state of charge, measure the resting high state of charge after allowing the battery to rest for a second rest period after the battery reaches the target high state of charge, and calculate the capacity of the battery based on the resting low state of charge and the resting high state of charge.
[0011] In addition to one or more of the features described herein, the processor is further configured to measure the accumulated charge on the battery while charging the battery and calculate the capacity of the battery based on the resting low state of charge, the resting high state of charge, and the accumulated charge.
[0012] In addition to one or more of the features described herein, the processor is configured to set the target low state of charge at a low end of an operating range of the battery and to set the target high state of charge at a high end of the operating range.
[0013] In addition to one or more of the features described herein, the processor is configured to perform at least one of: measuring a first voltage of the battery after the first rest period and determining the resting low state of charge based on the first voltage, and measuring a second voltage of the battery after the second rest period and determining the resting high state of charge based on the second voltage.
[0014] In addition to one or more of the features described herein, the processor is further configured to determine at least one of the resting low state of charge and the resting high state of charge using one of a lookup table correlating state of charge to voltage and a model equation correlating state of charge to voltage.
[0015] In addition to one or more of the features described herein, the processor is configured to estimate the capacity of the battery based on at least one of: the time since a previous update is greater than a selected time criterion, the mileage since the previous update is greater than a selected mileage criterion, and the variance of the values in the previous update is greater than a variance criterion.
[0016] In addition to one or more of the features described herein, the processor is configured to perform at least one of: running a diagnostic test on the battery based on the estimated capacity, calculating a state of charge of the battery based on the estimated capacity, and sending a signal to an operator indicating a state of health of the battery.
[0017] In yet another exemplary embodiment, a vehicle is disclosed. The vehicle includes a battery and a processor. The processor is configured to operate the vehicle to deplete the battery to reach a target low state of charge, measure the resting low state of charge after allowing the battery to rest for a first rest period after the battery reaches the target low state of charge, operate the vehicle to charge the battery to reach a target high state of charge, measure the resting high state of charge after allowing the battery to rest for a second rest period after the battery reaches the target high state of charge, and calculate a capacity of the battery based on the resting low state of charge and the resting high state of charge.
[0018] In addition to one or more of the features described herein, the processor is further configured to measure the accumulated charge on the battery while charging the battery and calculate the capacity of the battery based on the resting low state of charge, the resting high state of charge, and the accumulated charge.
[0019] In addition to one or more of the features described herein, the processor is configured to set the target low state of charge at a low end of an operating range of the battery and to set the target high state of charge at a high end of the operating range.
[0020] In addition to one or more of the features described herein, the processor is configured to perform at least one of: measuring a first voltage of the battery after the first rest period and determining the resting low state of charge based on the first voltage, and measuring a second voltage of the battery after the second rest period and determining the resting high state of charge based on the second voltage.
[0021] In addition to one or more of the features described herein, the processor is further configured to determine at least one of the resting low state of charge and the resting high state of charge using one of a lookup table correlating state of charge to voltage and a model equation correlating state of charge to voltage.
[0022] In addition to one or more of the features described herein, the processor is configured to estimate the capacity of the battery based on at least one of: the time since a previous update is greater than a selected time criterion, the mileage since the previous update is greater than a selected mileage criterion, and the variance of the values in the previous update is greater than a variance criterion.
[0023] The above features and advantages and other features and advantages of the present disclosure are apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Other features, advantages and details appear, by way of example only, from the following detailed description, which refers to the accompanying drawings, in which:
[0025] Figure 1 An embodiment of a vehicle in an illustrative embodiment is shown;
[0026] Figure 2 A flow chart illustrating a method for determining a charge capacity of a battery system of a vehicle is shown; and
[0027] Figure 3 A detailed flow chart of a method for estimating the capacity of a battery system in an embodiment is shown. DETAILED DESCRIPTION
[0028] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate the same or corresponding parts and features.
[0029] According to an illustrative embodiment, Figure 1 An embodiment of a vehicle 10 is shown that includes a body 12 that at least partially defines an occupant compartment 14. The body 12 also supports various vehicle subsystems, including a propulsion system 16, and other subsystems for supporting the functions of the propulsion system 16 and other vehicle components, such as a braking subsystem, a suspension system, a steering subsystem, a fuel injection subsystem, an exhaust subsystem, etc.
[0030] The vehicle 10 is a hybrid vehicle that includes an internal combustion engine assembly 18 and at least one electric motor assembly. For example, the propulsion system 16 includes a first electric motor 20 and a second electric motor 21. The first electric motor 20 and the second electric motor 21 can be configured to drive wheels on opposite sides of the vehicle 10. Any number of electric motors positioned at various locations can be used.
[0031] The vehicle 10 includes a battery system 22 that may be electrically connected to the first and second electric motors 20 and 21 and / or other components, such as vehicle electronics. The battery system 22 may be configured as a rechargeable energy storage system (RESS).
[0032] In an embodiment, the battery system 22 includes a battery assembly, such as a high voltage battery pack 24 having a plurality of battery modules 26. Each battery module 26 includes a plurality of individual battery cells (not shown). The battery system 22 may also include a monitoring unit 28 (e.g., a RESS controller) configured to receive measurements from sensors 30. Each sensor 30 may be an assembly or system having one or more sensors for measuring various battery and environmental parameters such as temperature, current, and voltage. The monitoring unit 28 includes components such as a processor, memory, interface, bus, and / or other suitable components.
[0033] The battery system 22 is electrically connected to a direct current (DC)-DC converter module 32 and an inverter module 34. The inverter module 34 (e.g., a traction power inverter unit or TPIM) converts direct current (DC) power from the battery assembly into three-phase alternating current (AC) power to drive the motor. In one embodiment, the inverter module 34 includes a first inverter 36 connected to the first motor 20 and a second inverter 38 connected to the second motor 21.
[0034] The battery system 22 may also be connected to other vehicle components or systems. For example, the battery system 22 is connected to an auxiliary power module (APM) 40 that controls power output to components such as a heating system. The APM 40 may be used to supply power from the battery system 22 for heating the passenger compartment 14.
[0035] The vehicle 10 may include a charging system that may be used to charge the high voltage battery pack 24 and / or to supply power from the high voltage battery pack 24 to charge another energy storage system (e.g., vehicle-to-vehicle charging). The charging system includes an onboard charging module (OBCM) 42 electrically connected to a charging port 44.
[0036] In an embodiment, the vehicle 10 includes a hybrid operating system 55 configured to control the operation of the vehicle 10, including controlling the selection and operation of the internal combustion engine assembly 18 and the at least one electric motor assembly. The hybrid operating system 55 communicates with the monitoring unit 28 and receives data from the monitoring unit 28. The hybrid operating system 55 includes a processing device or processor, which can be any suitable processor, such as the monitoring unit (e.g., RESS controller) 28, the OBCM 42, or a dedicated controller 46. The hybrid operating system 55 or processor can be used to perform various operations disclosed herein for determining or estimating the charge capacity of the battery of the vehicle.
[0037] The vehicle 10 also includes a computer system 48 including one or more processing devices 50 and a user interface 52. The various processing devices and units may communicate with each other via a communication device or system, such as a controller area network (CAN) or transmission control protocol (TCP) bus.
[0038] Figure 2 A flowchart 200 is shown illustrating a method for determining the charge capacity of the battery system 22 of the vehicle 10. In block 202, the battery is depleted until the state of charge of the battery reaches a target low state of charge (SOC TL ). SOC TL is selected as the SOC at the low end of the operating range of the battery system 22. The battery system 22 is depleted through operation of the vehicle 10, such as by driving the vehicle in an electric operating mode. In block 204, after the battery system 22 is allowed to rest for a first rest period, a rest low state of charge (SOC RL In block 206 , the battery is charged until the SOC reaches a target high state of charge (SOC TH ). SOC TH The SOC is selected as the SOC at the high end of the operating range of the battery system 22. The battery is charged by operation of the vehicle 10, such as by driving the vehicle in a combustion mode in which the internal combustion engine assembly 18 charges the battery. The accumulated charge at the battery is measured during the charging operation. In block 208, after the battery system 22 is allowed to rest for a second rest period, the rest high state of charge (SOC RH In block 210 , according to the static low SOC value (SOC RL ) and static high SOC value (SOC RH ) and the accumulated charge measured when charging the battery to determine the battery capacity.
[0039] Figure 3A detailed flow chart 300 of a method for estimating the capacity of a battery system 22 in an embodiment is shown. The method starts in box 302. In box 304, the processor determines whether the estimated capacity of the battery needs to be updated based on one or more criteria. For example, the processor can start a new estimation process when the amount of time since the previous update is greater than a selected time standard. In another example, the processor can start a new estimation process when the mileage since the previous update is greater than a selected mileage standard. In yet another example, the processor can start a new estimation process when the variance of the charge capacity calculated from the previous update is greater than a selected variance standard. In box 304, if an update is not required, the method proceeds to box 338, where the method ends. If an update is required, the method proceeds to box 306.
[0040] In box 306, the driving mode of the vehicle is determined. If the driving mode is not suitable for performing a capacity update (ie, sport mode or performance mode), the method proceeds to box 338, where the method ends. If the driving mode is suitable for performing a capacity update (ie, normal driving), the method proceeds to box 308.
[0041] In block 308, the processor sets a target low state of charge (SOC TL ). SOC TL is set at the lower end (low end) of the battery's available SOC range. As an example, SOC TL This can be up to 30% of the battery's charge capacity.
[0042] In block 310, the battery is depleted in order to achieve SOC TL When the vehicle is usually driven using one of the first motor 20 and the second motor 21, the battery is depleted. In block 312, the actual SOC is compared with the SOC TL If SOC is not reached yet, TL , the method proceeds to box 314. At box 314, the driving mode of the vehicle is checked. If the driving mode is not suitable for performing a capacity update, the method proceeds to box 338, where the method ends. Otherwise, if the driving mode is appropriate, the method proceeds to box 310. Returning to box 312, if the SOC has been reached TL , the method proceeds to box 316.
[0043] In block 316, the battery is maintained at a low target SOC (SOC TL ), until a shut-off event is received to shut down the vehicle. In box 318, the battery is allowed to rest for a first rest period, after which a rest low battery SOC (SOC LR). In various embodiments, the first rest period may be between 1-3 hours. After the first rest period, a first voltage of the battery is measured, and the SOC is determined using the first voltage. LR In one embodiment, the SOC may be determined using the measured voltage and a lookup table that relates voltage to SOC. RL In alternative embodiments, other methods may be used to calculate the SOC from the first voltage. RL , including equations, battery models, etc.
[0044] If a resting low battery SOC has not been determined at frame 318, the method proceeds to frame 320. If the vehicle is not in the appropriate mode (i.e., resting mode), the method proceeds to frame 338, where the method ends. Otherwise, the method proceeds to frame 316. Returning to frame 318, once a resting low battery SOC is determined, the method proceeds to frame 322.
[0045] In block 322, a high target SOC (SOC TH ). SOC TH Can be set at key-on (i.e. when the vehicle is turned on). SOC TH is set at the high end of the battery's usable range. As an example, SOC TH It can be 70% of the battery capacity.
[0046] In block 324, to achieve a high target SOC (SOC TH ) to charge the battery. When the vehicle is driven, the battery is typically charged using the internal combustion engine assembly 18. While the battery is charging, the processor calculates the accumulated battery pack charge Q Accum In one embodiment, an iterative process is used to calculate the accumulated battery charge, as shown in equation (1).
[0047] Q Accum (k)=Q Accum (k-1)+(I*∆t) / 3600 Equation (1)
[0048] Among them, Q Accum is the accumulated battery charge in ampere-hours, I is the current through the cell or battery in amperes, and t is the time in seconds. The accumulated charge at time step k is calculated based on the accumulated charge at the previous time step k-1.
[0049] In block 326, it is determined whether SOC has been achieved. TH If SOC is not reached TH, the method proceeds to box 328. At box 328, the driving mode of the vehicle is checked. If the driving mode is not suitable for performing a capacity update (i.e., if the mode is not normal driving), the method proceeds to box 338, where the method ends. Otherwise, if the driving mode is appropriate, the method proceeds to box 324. Returning to box 326, if the SOC has been reached TH , the method proceeds to box 330.
[0050] In block 330 , the processor maintains the SOC of the battery at or near the high target SOC until a shutoff command is received, thereby shutting down the vehicle.
[0051] In block 332, the battery system 22 is allowed to rest for a second rest period, and a rest high battery SOC (SOC RH ). In various embodiments, the second rest period may be between 1-3 hours. After the second rest period, a second voltage of the battery is measured, and the SOC is determined based on the second voltage. RH In one embodiment, the SOC may be determined based on the second voltage and a lookup table that relates voltage to SOC. RH In alternative embodiments, other methods may be used to calculate the SOC from the second voltage. RH , including equations, battery models, etc.
[0052] If a resting high battery SOC has not been determined at frame 332, the method proceeds to frame 334. If the vehicle is not in the appropriate mode (i.e., resting mode) at frame 334, the method proceeds to frame 338, where the method ends. Otherwise, the method proceeds to frame 330. Returning to frame 332, once a resting high battery SOC is determined, the method proceeds to frame 336.
[0053] In block 336, the estimated capacity of the battery is calculated. This may be based on a resting low state of charge (SOC RL ), static high charge state (SOC RH ) and the accumulated charge Q Accum To calculate the estimated capacity, as shown in equation (2):
[0054] Capacity estimate = Q Accum / (SOC RH -SOC RL ) Equation (2)
[0055] After estimating the battery capacity, the method proceeds to block 338 where the method ends.
[0056] In various embodiments, once the calculation is complete, the processor may send a signal indicating the health or charge state of the battery to a display viewable by the driver or operator. In an alternative embodiment, the processor may run a diagnostic test on the battery or vehicle based on the calculated capacity. In an alternative embodiment, the processor may calculate the charge state of the battery based on the estimated capacity. In an alternative embodiment, the processor may display a signal to the driver indicating that repair or maintenance is needed.
[0057] The terms "one" and "an" do not indicate a limitation of quantity, but rather indicate the presence of at least one of the referenced item. Unless the context clearly indicates otherwise, the term "or" means "and / or". References to "aspects" throughout the specification mean that a particular element (e.g., a feature, structure, step, or characteristic) described in conjunction with that aspect is included in at least one aspect described herein, and may or may not be present in other aspects. In addition, it should be understood that the described elements may be combined in any suitable manner in the various aspects.
[0058] When an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.
[0059] Unless otherwise indicated herein, all test standards are the most current standards in effect as of the filing date of this application or, if priority is claimed, the filing date of the earliest priority application in which the test standards appear.
[0060] Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.
[0061] Although the above disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted for its elements without departing from its scope. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the disclosure without departing from the basic scope of the disclosure. Therefore, it is intended that the disclosure is not limited to the specific embodiments disclosed, but will include all embodiments falling within its scope.
Claims
1. A method for calculating the battery capacity of a vehicle, comprising: depleting the battery to a target low state of charge during operation of the vehicle; After the battery reaches the target low state of charge, allowing the battery to rest for a first rest period; determining a rest low state of charge after said first rest period; charging the battery to a target high state of charge during operation of the vehicle; After the battery reaches the target high state of charge, allowing the battery to rest for a second rest period; determining a rest high state of charge after the second rest period; as well as The capacity of the battery is calculated based on the resting low state of charge and the resting high state of charge.
2. The method of claim 1 further comprising measuring a cumulative charge on the battery while charging the battery, and calculating a capacity of the battery based on the resting low state of charge, the resting high state of charge, and the cumulative charge.
3. The method of claim 1 further comprising at least one of: (i) measuring a first voltage of the battery after the first rest period and determining the resting low state of charge based on the first voltage; and (ii) measuring a second voltage of the battery after the second rest period and determining the resting high state of charge based on the second voltage.
4. The method of claim 1 further comprising estimating the capacity of the battery based on at least one of: (i) a time since a previous update is greater than a selected time criterion; (ii) a mileage since the previous update is greater than a selected mileage criterion; and (iii) a variance of values in a previous update is greater than a variance criterion.
5. The method of claim 1 , further comprising at least one of: (i) running a diagnostic test on the battery based on the calculated capacity; (ii) calculating a state of charge of the battery based on the calculated capacity; and (iii) sending a signal indicative of a state of health of the battery.
6. A system for calculating the battery capacity of a vehicle, comprising: A processor configured to: operating the vehicle to deplete the battery to a target low state of charge; measuring a resting low state of charge after allowing the battery to rest for a first rest period after the battery reaches the target low state of charge; operating the vehicle to charge the battery to a target high state of charge; measuring a resting high state of charge after allowing the battery to rest for a second rest period after the battery reaches the target high state of charge; as well as The capacity of the battery is calculated based on the resting low state of charge and the resting high state of charge.
7. The system according to claim 6, wherein: The processor is further configured to measure an accumulated charge on the battery while charging the battery and calculate a capacity of the battery based on the resting low state of charge, the resting high state of charge, and the accumulated charge.
8. The system according to claim 6, wherein: The processor is also configured to perform at least one of: (i) measuring a first voltage of the battery after the first rest period and determining the resting low state of charge based on the first voltage; and (ii) measuring a second voltage of the battery after the second rest period and determining the resting high state of charge based on the second voltage.
9. The system according to claim 6, wherein: The processor is also configured to estimate the capacity of the battery based on at least one of: (i) a time since a previous update is greater than a selected time criterion; (ii) a mileage since the previous update is greater than a selected mileage criterion; and (iii) a variance of values in previous updates is greater than a variance criterion.
10. The system according to claim 6, wherein: The processor is further configured to perform at least one of: (i) running a diagnostic test on the battery based on the calculated capacity; (ii) calculating a state of charge of the battery based on the calculated capacity; and (iii) sending a signal to an operator indicating the state of health of the battery.