System for charging and discharging a vehicle battery based on a state of charge

Abstract

A system for charging and discharging a vehicle battery. The vehicle can receive at least a portion of its propulsion power from an internal combustion engine (ICE) connected to a generator, or alternatively, it can receive all of its propulsion power from one or more electric motors powered by a traction battery pack that communicates electrically with an auxiliary power module (APM). The system charges and discharges the vehicle battery based on a comparison between the current state of charge (State of Charge) and the target state of charge range. This charging and discharging process creates a balance between the battery's charging and discharging capacities.

Description

INTRODUCTION

[0001] The present invention relates to a system for charging and discharging a vehicle battery based on the state of charge (SOC) of the vehicle battery. In one embodiment, the vehicle receives at least part of its propulsion power from an internal combustion engine (ICE). In an alternative embodiment, the vehicle is a purely electric vehicle (EV).

[0002] For general background information, reference should be made in advance to the publications DE 10 2008 008 238 A1 and DE 10 2015 007 913 A1.

[0003] A starter battery (SLI, starting, lighting, and ignition battery), also known as a vehicle battery or auxiliary battery, is a rechargeable battery that provides power to a starter motor to start a vehicle's internal combustion engine. The vehicle battery also supplies power to various auxiliary electrical devices in the vehicle, such as the headlights and taillights, air conditioning, and radio. Some electric vehicles (EVs) also include a vehicle battery in addition to the traction battery pack. When used in an electric vehicle, the vehicle battery may be referred to as an auxiliary battery.

[0004] There are a number of challenges that can occur with a vehicle battery. For example, start-stop combustion engines automatically switch off when the vehicle is idling and restart when the driver releases the brake pedal. When the start-stop engine is off, the vehicle needs the electrical energy to operate its electrical components from the vehicle battery rather than the alternator, resulting in significantly more battery discharge cycles.

[0005] Another challenge for a vehicle battery can be sulfation. Sulfation refers to the buildup of lead sulfate crystals on and within the pores of the lead plates in a lead-acid battery. If left unattended, these crystals continue to grow and harden over time, which can impair the battery's charging and discharging capabilities. A vehicle battery's state of charge (SOC) is expressed as the ratio between its available capacity and the maximum charge it can hold. A vehicle battery's capacity and its ability to hold a charge decrease over time. Therefore, an older vehicle battery will have a lower SOC and a lower charge-holding capacity compared to a new battery, even when subjected to the same charging conditions.

[0006] Although current vehicle batteries fulfill their purpose, there is therefore a need for an improved method for charging and discharging vehicle batteries. SUMMARY

[0007] According to the invention, a system for charging and discharging a vehicle battery in a vehicle is presented, characterized by the features of claim 1.

[0008] In one aspect, the one or more controllers execute the charging cycle by determining the battery temperature of the vehicle battery and comparing the battery temperature with a target battery temperature range.

[0009] In yet another aspect, the one or more controllers execute the charging cycle by instructing the alternator, in response to determining that the battery temperature is within the target battery temperature range, to pulse-charge the vehicle battery by increasing the RVC voltage supplied to the vehicle battery at a rate limited by the alternator's scaling rate. Pulse charging comprises: starting the RVC voltage at a neutral target charging voltage; increasing the RVC voltage to a maximum vehicle battery charging voltage; and maintaining the RVC voltage at the maximum vehicle battery charging voltage for a fourth period.

[0010] In yet another aspect, the maximum charging voltage of the vehicle battery is adjusted based on the battery temperature, and a temperature-adjusted maximum charging voltage is expressed as follows: temperature-adjusted maximum charging voltage = Vstd + (25 - Tt)*0.003*6 where Tt represents a real temperature of the vehicle battery and Vstd is a standard maximum charging voltage of the vehicle battery during pulse charging.

[0011] In one aspect, the one or more controllers execute the charging cycle by instructing the alternator, in response to determining that the battery temperature is falling outside the target battery temperature range, to pulse-charge the vehicle battery by increasing the RVC voltage supplied to the vehicle battery at a rate limited by the alternator's scaling rate. Pulse charging includes: starting the RVC voltage at a neutral target charging voltage, increasing the RVC voltage to a maximum temperature-adjusted voltage based on the battery temperature (where the maximum temperature-adjusted voltage of the vehicle battery is a function of the battery temperature), and maintaining the RVC voltage at the maximum temperature-adjusted voltage of the vehicle battery for a fourth time interval.

[0012] In another aspect, the maximum temperature-adjusted voltage of the vehicle battery is 14, with an adjusted maximum charging voltage of 0.003 volts / cell, and where the adjusted maximum charging voltage is expressed as: Vadjust=Vstd+(25−Tt)*0.003*6 where Vadjust represents the adjusted maximum charging voltage, Tt represents a real temperature of the vehicle battery, and Vstd represents a maximum standard charging voltage of the vehicle battery during pulse charging.

[0013] In yet another aspect, one or more controllers perform a charging cycle: instructing the generator to reduce the RVC voltage to a neutral charge target voltage in order to charge the vehicle for a fifth period, the first period, the second period, the third period, the fourth period and the fifth period each being chosen such that the total charging time required for the vehicle battery is a predetermined percentage of the vehicle's total operating time.

[0014] In one aspect, the one or more controllers execute instructions to compare the state of charge of the vehicle battery with a lowest value of the target state of charge range, and in response to determining that the state of charge of the vehicle battery is equal to or less than the lowest value of the target state of charge range, to compare a voltage of the vehicle battery with a threshold resting voltage, where the threshold resting voltage indicates that the replacement of the vehicle battery is necessary.

[0015] In another aspect, the vehicle battery is a 12-volt DC battery; the regular discharge target current is about 0.25 C20 and the regular discharge target voltage is not lower than about 11.5 volts.

[0016] Furthermore, a method for charging and discharging a vehicle battery in a vehicle is described, wherein the vehicle receives at least a portion of its drive power from an internal combustion engine (ICE) that drives a generator. The method includes determining the state of charge of the vehicle battery by one or more controllers, the one or more controllers being in electronic communication with the vehicle battery and the generator. The method includes comparing the state of charge of the vehicle battery with a target state of charge range by the one or more controllers. In response to determining that the state of charge of the vehicle battery falls within the target state of charge range, the method includes instructing the vehicle battery to discharge at a regular discharge target current for an initial period while maintaining a voltage of the vehicle battery at a regular discharge target voltage.The method comprises instructing the vehicle battery, by one or more controllers, to discharge at a neutral discharge target current for a second time period at a neutral discharge target voltage, the second time period being shorter than the first. The method comprises instructing the vehicle to start moving, by one or more controllers, the generator being driven by the ICE during vehicle start-up. Finally, the method comprises instructing the generator, by one or more controllers, to perform at least a minimum number of charge cycles to charge and discharge the vehicle battery based on a regulator voltage control (RVC), the charging and discharging of the vehicle battery generating a balance between the charging capacity and the discharging capacity of the vehicle battery.

[0017] Furthermore, another system for charging and discharging a vehicle battery is described, wherein the vehicle receives all its tractive power from one or more electric motors supplied by a traction battery pack that communicates electrically with an auxiliary power module (APM). The system includes one or more controllers in electronic communication with the vehicle battery and the APM. The one or more controllers include one or more processors that execute instructions to determine the state of charge of the vehicle battery. The one or more controllers compare the state of charge of the vehicle battery with a target state of charge range.In response to the determination that the vehicle battery's state of charge is falling within the target state of charge range, the one or more controllers instruct the vehicle battery to discharge at an initial target discharge current for an initial period while maintaining a vehicle battery voltage at a regular target discharge voltage. The one or more controllers then instruct the vehicle to start moving, with the APM supplying an APM voltage to the vehicle battery during this start-up phase. The one or more controllers instruct the APM to perform at least a minimum number of charge cycles to charge and discharge the vehicle battery based on an APM voltage, whereby the charging and discharging of the vehicle battery establishes a balance between the vehicle battery's charge capacity and discharge capacity.

[0018] In another aspect, the one or more controllers perform a charging cycle by instructing the APM to reduce the APM voltage supplied to the vehicle battery in order to lower the vehicle battery voltage to the regular discharge target voltage for a second period of time, the second period being longer than the first period of time.

[0019] In yet another aspect, the one or more controllers execute the charging cycle by determining the battery temperature of the vehicle battery and comparing the battery temperature with a target battery temperature range.

[0020] In one aspect, the one or more controllers execute the charging cycle by instructing the APM, in response to determining that the battery temperature is falling within the target battery temperature range, to pulse-charge the vehicle battery by increasing the APM voltage supplied to the vehicle battery at a rate limited to the APM's scaling rate. Pulse charging includes: starting the APM voltage at a neutral charge target voltage; increasing the APM voltage to a maximum vehicle battery charging voltage; and maintaining the APM voltage at the maximum vehicle battery charging voltage for a third period.

[0021] In another aspect, the one or more controllers execute the charging cycle by instructing the APM to pulse-charge the vehicle battery in response to the determination that the battery temperature is falling outside the target battery temperature range. This is achieved by increasing the APM voltage supplied to the vehicle battery at a rate limited by the APM's scaling rate. Pulse charging involves starting the APM voltage at a neutral charge target voltage, increasing the APM voltage to a maximum temperature-adjusted voltage based on the battery temperature (where the maximum temperature-adjusted voltage of the vehicle battery is a function of the battery temperature), and maintaining the APM voltage at the maximum temperature-adjusted voltage of the vehicle battery for a third period.

[0022] In yet another aspect, the maximum temperature-adjusted voltage of the vehicle battery is 14, with an adjusted maximum charging voltage of 0.003 volts / cell, where the adjusted maximum charging voltage is expressed as: Vadjust=Vstd+(25−Tt)*0.003*6 where Vadjust represents the adjusted maximum charging voltage, Tt represents a real temperature of the vehicle battery, and Vstd represents a maximum standard charging voltage of the vehicle battery during pulse charging.

[0023] In one aspect, the one or more controllers execute the charging cycle by instructing the APM to reduce the APM voltage to the neutral charge target voltage in order to charge the vehicle battery for a fourth period of time.

[0024] In another aspect, the one or more controllers execute the charging cycle by instructing the APM to reduce the APM voltage to the regular discharge target voltage, discharging the vehicle battery with a neutral discharge target current for a fifth time period, the first, second, third, fourth and fifth time periods being each chosen such that the total charging time required for the vehicle battery is a predetermined percentage of the vehicle's total operating time.

[0025] Further areas of application will become apparent from the description provided herein. It is understood that the description and specific examples serve only as illustrations. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are for illustrative purposes only. Fig. Figure 1A is a schematic diagram of the disclosed system in a vehicle which receives at least a proportion of its motive power from an internal combustion engine (ICE), wherein, according to an exemplary embodiment, the system comprises one or more controllers in electronic communication with a vehicle battery; Fig. Figure 1B is a schematic diagram of the disclosed system in a pure electric vehicle (EV), according to an exemplary embodiment; Fig. 2 is a process flow diagram that shows a procedure for charging and discharging the vehicle battery using the [device / system / etc.]. Fig. The system shown in 1A illustrates when the vehicle receives at least a portion of its driving power from an internal combustion engine, according to an exemplary embodiment; and Fig. 3 is a process flow diagram that shows a procedure for charging and discharging the vehicle battery using the [device / system / etc.]. Fig. The system shown in Figure 1B illustrates, when the vehicle is an EV, according to an exemplary embodiment. DETAILED DESCRIPTION

[0027] The following description is merely an example.

[0028] With reference to Fig. Figure 1A illustrates an exemplary vehicle 10 that includes the disclosed battery charging system 12 for charging and discharging a vehicle battery 14. The vehicle battery 14 can also be referred to as a starter battery (SLI). The vehicle battery 14 is a rechargeable battery used to start the vehicle 10 and to provide power to one or more auxiliary electrical devices 16 that are part of the vehicle 10, such as, but not limited to, headlights, taillights, and a radio or sound system. The vehicle 10 can be any type of vehicle, such as, but not limited to, a sedan, truck, SUV, van, or motorhome. In the embodiment as shown in Figure 1A, the vehicle battery 14 is a rechargeable battery used to start the vehicle 10 and to provide power to one or more auxiliary electrical devices 16 that are part of the vehicle 10, such as, but not limited to, headlights, taillights, and a radio or sound system. Fig. As shown in Figure 1A, the vehicle 10 receives at least a portion of its propulsion power from an internal combustion engine (ICE) 18, and the HEV vehicle 10 is either an ICE vehicle or a hybrid electric vehicle (HEV). In an alternative embodiment, as shown in Fig. As shown in Figure 1B, the vehicle 10 is a pure electric vehicle (EV) that receives all its propulsion energy from one or more electric motors 20, which are supplied by a traction battery pack 22.

[0029] Referring to both Fig. 1A and Fig. 1B comprises the battery charging system 12, the vehicle battery 14, and one or more controllers 30 that communicate electronically with the vehicle battery 14. The one or more controllers 30 communicate electronically with one or more voltage sensors 32, one or more current sensors 34, one or more state-of-charge sensors 36, and one or more temperature sensors 38. The one or more voltage sensors 32 monitor the voltage of the vehicle battery 14 in real time, the one or more current sensors 34 monitor the discharge current of the vehicle battery 14 in real time, the one or more state-of-charge sensors 36 monitor the state of charge of the vehicle battery 14 in real time, and the one or more temperature sensors 38 monitor the battery temperature of the vehicle battery 14 in real time.In one embodiment, the charge state sensors 36 are omitted, and the one or more controllers 30 determine the charge state based on the voltage of the vehicle battery 14.

[0030] As in Fig. As shown in Figure 1A, when vehicle 10 includes the ICE 18, the vehicle battery 14 is electrically connected to a starter motor 40 and a generator 42. The vehicle battery 14 provides power to the starter motor 40 to start the ICE 18. The generator 42 is driven by a crankshaft (not shown) of the ICE 18 when the vehicle 10 starts. The generator 42 includes a rate-of-rise generator, where the rate-of-rise specifies the maximum rate of change per unit of time for either an output voltage or an output current of the generator 42. The generator 42 provides a regulated voltage control (RVC) voltage to the vehicle battery 14, where the RVC voltage is an output voltage of the generator 42 that is regulated based on the battery temperature of the vehicle battery 14.If the RVC voltage is less than the voltage of the vehicle battery 14, the vehicle battery 14 discharges and provides electrical current for one or more electrical accessories 16 that are part of the vehicle 10.

[0031] With reference to Fig. 1B, when the vehicle 10 receives all of its propulsion power from the one or more electric motors 20 supplied by the traction battery pack 22, the one or more controllers 30 communicate electronically with the traction battery pack 22 and an Auxiliary Power Module (APM) 44. The APM 44 includes a slew rate, which specifies a maximum rate of change per unit of time for either an output voltage or an output current of the APM 44. The APM 44 communicates electrically with the traction battery pack 22 and converts the high voltage supplied by the traction battery pack 22 into a regulated voltage, referred to as the APM voltage. The APM voltage is supplied to the vehicle battery 14, with the APM voltage being regulated based on the battery temperature of the vehicle battery 14.If the APM voltage is less than the voltage of the vehicle battery 14, the vehicle battery 14 discharges and provides electrical current for one or more electrical auxiliary devices 16 that are part of the vehicle 10.

[0032] An approach to charging and discharging the vehicle battery 14 based on the state of charge and the battery temperature is now described. Fig. Figure 2 is a process flow diagram illustrating a method 200 for charging and discharging the vehicle battery 14, where the vehicle 10 is either an ICE vehicle or a HEV. It can be noted that the method 200 establishes a balance between the charging capacity and the discharging capacity of the vehicle battery 14 and maintains the vehicle battery 14 within a target state-of-charge range until the end of its service life. When the charging capacity and the discharging capacity of the vehicle battery 14 are balanced, the charging capacity is approximately equal to the discharging capacity. As an example, in one embodiment, the target state-of-charge range is from approximately seventy percent to approximately ninety percent.

[0033] Referring generally to Fig. 1A and Fig. 2. Procedure 200 can begin in block 202. In block 202, the one or more controllers 30 determine the state of charge of the vehicle battery 14 either from the one or more voltage sensors 32 or the one or more state-of-charge sensors 36. It should be noted that the state of charge of the vehicle battery 14 is determined at the beginning of the day, before the start of the ICE 18. Procedure 200 can then proceed to decision block 204.

[0034] In decision block 204, the one or more controllers 30 compare the state of charge of the vehicle battery 14 with the target state of charge range of the vehicle battery 14. If the system determines that the state of charge of the vehicle battery 14 is outside the target state of charge range, the procedure 200 can then proceed to decision block 206. Otherwise, the procedure 200 can continue with block 216.

[0035] In decision block 206, the one or more controllers 30 compare the state of charge of the vehicle battery 14 with the lowest value of the target state of charge range to determine whether the state of charge of the vehicle battery 14 is equal to or less than the lowest value of the target state of charge range. In response to the determination that the state of charge of the vehicle battery 14 is greater than the highest value of the target state of charge range, the procedure 200 can proceed to block 208.

[0036] In block 208, in response to the determination that the state of charge of the vehicle battery 14 is greater than the highest value of the state of charge range, the one or more controllers 30 execute blocks 216, 218, 220, 222, 224, and 232 of procedure 200 until the state of charge of the vehicle battery 14 falls within the target state of charge range (blocks 226, 228, and 230 are skipped). Once the target state of charge of the vehicle battery 14 falls within the target state of charge range, the procedure can continue with blocks 216-232 as described below.

[0037] Referring again to decision block 206, the procedure 200, in response to determining that the state of charge of the vehicle battery 14 is equal to or less than the lowest value of the target state of charge range, can proceed to decision block 210. In decision block 210, the one or more controllers 30 compare the voltage of the vehicle battery 14 with a threshold resting voltage to determine whether the voltage of the vehicle battery 14 is less than the threshold resting voltage. The threshold resting voltage indicates that the vehicle battery 14 needs to be replaced. By way of example only, in one embodiment the threshold resting voltage is approximately 11.8 volts if the vehicle battery 14 is a 12-volt battery.In response to the determination that the voltage of vehicle battery 14 is below the threshold resting voltage, the procedure continues with block 212, the vehicle battery 14 is replaced, and procedure 200 is terminated. In response to the determination that the voltage of vehicle battery 14 is equal to or greater than the threshold resting voltage, the procedure continues with block 214.

[0038] In block 214, the procedure 200 can then continue with block 216. In block 216, the one or more controllers 30 first execute blocks 216 to 232 and then execute the charge cycles 234 (omitting block 224) to charge and discharge the vehicle battery 14 based on the RVC voltage. Each charge cycle 234 is executed in blocks 222-232 of the in Fig. The process is described in the process flow diagram shown in Figure 2. The one or more controllers 30 execute the charging cycles 234 until the state of charge of the vehicle battery 14 is within the target state of charge.

[0039] Referring again to Block 204, Method 200, in response to determining that the state of charge of the vehicle battery 14 falls within the target state of charge range, proceeds to Block 216. In Block 216, the one or more controllers 30 instruct the vehicle battery 14 to discharge at the regular discharge target current for the first time interval A, while maintaining the voltage of the vehicle battery 14 at the regular discharge target voltage. In one embodiment, the vehicle battery 14 is a 12-volt DC battery, and the regular discharge target current is about 0.25 C20, the regular discharge target voltage is not less than about 11.5 volts, and the first time interval A is about 11 seconds. It should be noted that the regular discharge target voltage can vary based on the temperature of the vehicle battery 14. Method 200 can then proceed to Block 218.

[0040] In block 218, the one or more controllers 30 instruct the vehicle battery 14 to discharge itself during the second time interval B with a neutral discharge target current at the neutral charge target voltage. It should be noted that the second time interval B is shorter than the first time interval A. In an embodiment where the vehicle battery 14 is a 12-volt DC battery, the neutral discharge target current is approximately 0.05 C20, the second time interval B is approximately 5 seconds, and the neutral discharge target voltage is at least approximately 12.3 volts. It should be noted that the neutral discharge target voltage can vary depending on the temperature and state of charge of the vehicle battery 14. Method 200 can then proceed to block 220.

[0041] In block 220, the one or more controllers 30 instruct the vehicle 10 to start, which is done by supplying electrical current to the starter motor 40. The generator 42 is driven by the ICE 18 when the vehicle 10 starts moving. Procedure 200 can then proceed to block 222.

[0042] In block 222, one or more controllers 30 can then instruct the generator 42 to perform at least a minimum number of charge cycles 234 to charge and discharge the vehicle battery 14 based on the RVC voltage, with each charge cycle 234 occurring in blocks 222-232 of the Fig. The process flow diagram shown in section 2 describes the process flow diagram, and the minimum number of charge cycles 234 is six. Each charge cycle 234 comprises increasing the RVC voltage supplied to the vehicle battery 14 by the generator 42 to raise the voltage of the vehicle battery 14 to the neutral discharge target voltage described in block 218 for a third time interval C, lowering the RVC voltage of the vehicle battery 14 to the regular discharge target voltage described in block 216 for the first time interval A, and performing a pulse charge in which the RVC voltage is adjusted based on the rate of rise of the generator 42. Specifically, the one or more controllers 30 in block 222 instruct the generator 42 to raise the RVC voltage provided to the vehicle battery 14 for the third time period C to the neutral discharge target voltage, where the third time period is less than the first time period A.In one embodiment, the third time interval is approximately five seconds. Method 200 can then proceed to block 224.

[0043] In block 224, the one or more controllers 30 instruct the generator 42 to reduce the RVC voltage supplied to the vehicle battery 14 in order to increase the discharge current of the vehicle battery 14 to the regular discharge target current for the first time interval A. The procedure 200 can then proceed to decision block 226.

[0044] In decision block 226, the one or more controllers 30 monitor the one or more temperature sensors 38 to determine the battery temperature of the vehicle battery 14. The one or more controllers 30 compare the battery temperature with a target battery temperature range. If the method 200 determines that the battery temperature is falling within the target battery temperature range, it can proceed to block 228. Otherwise, it proceeds to block 230. In one embodiment, the target battery temperature range is approximately 25 °C ± 5 °C. It is noted that the maximum charging voltage of the vehicle battery 14 is 15.7 volts.

[0045] In block 228, the one or more controllers 30 instruct the generator 42 to pulse-charge the vehicle battery 14 by increasing the RVC voltage supplied to the vehicle battery 14 at a rate limited to the ramp-up rate of the generator 42. The pulse charge comprises starting the RVC voltage at a neutral charge target voltage, increasing the RVC voltage to a maximum charging voltage of the vehicle battery 14, and maintaining the RVC voltage at the maximum charging voltage of the vehicle battery 14 for a fourth time interval D. The neutral charge target voltage is greater than the open-circuit voltage (OCV) of the vehicle battery 14 at the target state of charge. In one embodiment, the neutral charge target voltage is 0.13 volts greater than the open-circuit voltage (OCV) of the vehicle battery 14 at the target state of charge, the neutral charge target voltage being a fixed value for all state-of-charge values.In one embodiment where the vehicle battery 14 is a 12-volt battery, the maximum charging voltage of the vehicle battery 14 is 15.7 volts at 25 °C ± 5 °C under standard operating conditions. It should be noted that the maximum charging voltage of the vehicle battery 14 is limited based on system loads that do not accept more than 16 volts. It should also be noted that the maximum charging voltage of the vehicle battery 14 can be adjusted depending on the temperature of the vehicle battery 14. In one embodiment, a temperature-adjusted value for the maximum charging voltage is expressed as follows: temperature-adjusted maximum charging voltage = Vstd + (25 - Tt)*0.003*6, where Tt is the actual temperature of the vehicle battery 14 and Vstd is a standard maximum charging voltage of the vehicle battery 14 during pulse charging.In addition to the temperature of the vehicle battery 14, the maximum charging voltage can also be limited based on the vehicle requirements. The fourth time interval D is less than the first time interval A. In one embodiment, the fourth time interval D is approximately four seconds.

[0046] Referring again to decision block 226, procedure 200 can proceed to block 230 in response to the determination that the battery temperature is outside the target battery temperature range. In block 230, the one or more controllers 30 instruct the generator 42 to pulse charge the vehicle battery 14 by increasing the RVC voltage supplied to the vehicle battery 14 at a rate limited to the scaling rate of the generator 42. The pulse charge includes starting the RVC voltage at a neutral charge target voltage, increasing the RVC voltage to a maximum temperature-adjusted voltage based on the battery temperature, and maintaining the RVC voltage at the maximum temperature-adjusted voltage of the vehicle battery 14 for the fourth time interval D. The maximum temperature-adjusted voltage of the vehicle battery 14 is a function of the temperature of the vehicle battery 14.In one embodiment, the maximum temperature-adjusted voltage of the vehicle battery 14 is 0.003 volts / cell with an adjusted maximum charging voltage Vadjust, where Vadjust = Vstd + (25 - Tt)*0.003*6, where Vstd is the standard maximum charging voltage of the vehicle battery 14 during pulse charging and Tt is the actual temperature of the vehicle battery 14, where the actual temperature Tt is either less than 20 °C or more than 30 °C. The set maximum charging voltage Vadjust is not higher than 15.2 volts at the highest operating temperature of the vehicle battery 14 and not higher than 16 volts at the lowest operating temperature of the vehicle battery 14. Alternatively, the maximum temperature-adjusted voltage is based on the manufacturer's specifications.In one embodiment, the maximum temperature-adjusted voltage can also be limited based on vehicle requirements under certain operating conditions, for example, when the vehicle's high beams are also switched on. As in . Fig. Once 2 is visible, both blocks 228 and 230 can then continue with block 232.

[0047] In block 232, the one or more controllers 30 instruct the generator 42 to reduce the RVC voltage to the neutral charge target voltage in order to charge the vehicle 10 for a fifth time interval E. The fifth time interval E is shorter than the first time interval A. In one embodiment, the fifth time interval E is approximately seven seconds. The method 200 can then return to blocks 202, 204, 216, or 222 to perform another charge cycle 234. Alternatively, the method 200 can be terminated when the vehicle battery 14 has completed the minimum number of charge cycles 234.

[0048] It can be stated that the first time interval A, the second time interval B, the third time interval C, the fourth time interval D, and the fifth time interval E are each chosen such that the total charging time for the vehicle battery 14 is a predetermined percentage (i.e., x%) of the total operating time of the vehicle 10. The total operating time of the vehicle 10 is equal to the sum of the total charging time and the total discharging time (total operating time = total charging time + total discharging time).

[0049] Fig. Figure 3 is a process flow diagram illustrating a procedure 300 for charging and discharging the vehicle battery 14, where the vehicle 10 is an EV that receives all its tractive power from one or more electric motors 20 supplied by the traction battery pack 22. Referring generally to Fig. 1B and Fig. 3. Procedure 300 can begin in block 302. In block 302, the one or more controllers 30 determine the state of charge of the vehicle battery 14 either from the one or more voltage sensors 32 or the one or more state-of-charge sensors 36. Procedure 300 can then continue with decision block 304.

[0050] In decision block 304, the one or more controllers 30 compare the state of charge of the vehicle battery 14 with the target state of charge range of the vehicle battery 14. If the controller determines that the state of charge of the vehicle battery 14 is outside the target state of charge range, the procedure 300 can then proceed to decision block 306. Otherwise, the procedure 300 can continue with block 316.

[0051] In decision block 306, the one or more controllers 30 compare the state of charge of the vehicle battery 14 with the lowest value of the target state of charge range to determine whether the state of charge of the vehicle battery 14 is equal to or less than the target state of charge. As a response to determining that the state of charge of the vehicle battery 14 is equal to or greater than the highest value of the target state of charge range, the procedure 300 can proceed to block 308.

[0052] In block 308, in response to determining that the state of charge of the vehicle battery 14 is greater than the highest value of the state of charge range, the one or more controllers 30 execute blocks 316, 318, 320, 328, and 330 of procedure 300, while omitting blocks 322, 324, and 326, until the state of charge of the vehicle battery 14 falls within the target state of charge range. Once the target state of charge of the vehicle battery 14 falls within the target state of charge range, procedure 300 can proceed with blocks 316-330, as described below.

[0053] Referring again to decision block 306, procedure 300, in response to the determination that the state of charge of the vehicle battery 14 is less than the lowest value of the target state of charge range, may proceed to decision block 310. In block 310, the one or more controllers 30 compare the voltage of the vehicle battery 14 with the threshold resting voltage. In response to the determination that the voltage of the vehicle battery 14 is below the threshold resting voltage, the procedure proceeds to block 312, the vehicle battery 14 is replaced, and procedure 300 terminates. In response to the determination that the voltage of the vehicle battery 14 is equal to or greater than the threshold resting voltage, the procedure proceeds to block 314.

[0054] In block 314, the one or more controllers 30 discharge the vehicle battery 14 with the initial target discharge current for the first time interval A2, as described in block 316, and then proceed to block 318. The one or more controllers 30 can then proceed with the execution of blocks 318-330 as described below, omitting block 320, until the state of charge of the vehicle battery 14 falls within the target state of charge range.

[0055] Referring again to decision block 304, the method 300, in response to the determination that the state of charge of the vehicle battery 14 falls within the target state of charge range, proceeds to block 316. In block 316, the one or more controllers 30 instruct the vehicle battery 14 to discharge at the initial target discharge current for the first time interval A2, while maintaining the voltage of the vehicle battery 14 at the regular target discharge voltage. The initial target discharge current is based on the current required for the vehicle 10. In one embodiment, the first time interval A2 is approximately ten seconds, and the initial target discharge current is approximately 0.25 C20. The method 300 can then proceed to block 318.

[0056] In block 318, the one or more controllers 30 instruct the vehicle 10 to start moving. The traction battery pack 22 provides power to the one or more electric motors 20, and the APM 44 provides the APM voltage to the vehicle battery 14 when the vehicle 10 starts. The procedure 300 can then proceed to block 320.

[0057] In block 320, the one or more controllers 30 can then instruct the APM 44 to perform at least a minimum number of charge cycles 332 to charge and discharge the vehicle battery 14 based on the APM voltage, with each charge cycle 332 occurring in blocks 320-330 of the Fig. This is described in the process flow diagram shown in Figure 3. In particular, the one or more controllers 30 in block 320 instruct the APM 44 to reduce the APM voltage supplied to the vehicle battery 14 in order to lower the voltage of the vehicle battery 14 for the second time interval B2 to the regular discharge target voltage, which is not lower than approximately 11.5 volts. In one embodiment, the second time interval B is approximately thirteen seconds, and the second time interval B2 is longer than the first time interval A2. The method 300 can then proceed to decision block 322.

[0058] In decision block 322, the one or more controllers 30 monitor the temperature sensor(s) 38 to determine the battery temperature of the vehicle battery 14. The one or more controllers 30 compare the battery temperature with the target battery temperature range. If the determination is made that the battery temperature is falling within the target battery temperature range, the procedure 300 can proceed to block 324. Otherwise, the procedure proceeds to block 326.

[0059] In block 324, the one or more controllers 30 instruct the APM to pulse-charge the vehicle battery 14 by increasing the APM voltage supplied to the vehicle battery 14 at a rate limited to the scaling rate of the APM 44. The pulse charge comprises starting the APM voltage at the neutral charge target voltage, increasing the APM voltage to the maximum charging voltage of the vehicle battery 14, and maintaining the APM voltage at the maximum charging voltage of the vehicle battery 14 for a third time interval C2. The third time interval C2 is less than the first time interval A2 and the second time interval B2. In one embodiment, the third time interval C2 is approximately three seconds.

[0060] Referring again to decision block 322, the procedure 300 can proceed to block 326 in response to the determination that the battery temperature is outside the target battery temperature range. In block 326, the one or more controllers 30 instruct the APM 44 to pulse charge the vehicle battery 14 by increasing the APM voltage supplied to the vehicle battery 14 at a rate limited to the scaling rate of the APM 44. The pulse charge includes starting the APM voltage at the neutral charge target voltage, increasing the APM voltage to the maximum temperature-adjusted voltage based on the battery temperature, and maintaining the APM voltage at the maximum temperature-adjusted voltage of the vehicle battery 14 for the third time interval C2. The maximum temperature-adjusted voltage of the vehicle battery 14 is calculated based on the approach described above in block 230. As in Fig.Once 3 is visible, both blocks 324 and 326 can then continue with block 328.

[0061] In block 328, the one or more controllers 30 instruct the APM 44 to reduce the APM voltage to the neutral charge target voltage in order to charge the vehicle battery 14 for a fourth time interval D2. The fourth time interval D2 is less than the first time interval A2 and the second time interval B2. In one embodiment, the fourth time interval D2 is approximately eight seconds. The method 300 can then proceed to block 330.

[0062] Block 330 instructs the one or more controllers 30 to the APM 44 to reduce the APM voltage to the regular discharge target voltage, and the vehicle battery 14 discharges for a fifth time interval E2 at the neutral discharge target current. The fifth time interval E2 is less than the first time interval A2 and the second time interval B2. In one embodiment, the fifth time interval E2 is approximately seven seconds. The process 300 can then return to block 320 to perform another charge cycle 332. Alternatively, the process 300 can be terminated when the vehicle battery 14 has completed the minimum number of charge cycles 332.

[0063] The system for charging and discharging a vehicle battery, disclosed in the figures, provides various technical effects and advantages. In particular, the system improves the state of charge of the vehicle battery during operation, improves fuel consumption, creates a balance between the charging and discharging capacities of the vehicle battery, and maintains the vehicle battery within the target state of charge range until the end of its service life. Furthermore, the disclosed system can also remove sulfation from the lead plates of a lead-acid battery before crystallization occurs, thus preventing or reducing sulfation of the battery. legend

[0064] In the drawing figures, N stands for no and Y for yes.

Claims

[1] System for charging and discharging a vehicle battery (14) in a vehicle (10), wherein the vehicle (10) receives at least a proportion of drive power from an internal combustion engine (ICE) (18) which drives a generator (42), the system comprising: one or more controllers (30) in electronic communication with the vehicle battery (14) and the generator (42), wherein the one or more controllers (30) comprise one or more processors that execute instructions to: to determine the state of charge of the vehicle battery (14) by means of one or more controllers (30); to compare the state of charge of the vehicle battery (14) with a target state of charge range of the vehicle battery (14); in response to a determination that the comparison found that the state of charge of the vehicle battery (14) falls within the target state of charge range, to instruct the vehicle battery (14) to discharge at a regular discharge target current for an initial period of time while maintaining a voltage of the vehicle battery (14) at a regular discharge target voltage; then to instruct the vehicle battery (14) to discharge itself with a neutral discharge target current for a second period at a neutral discharge target voltage, the second period being less than the first period; then to instruct the vehicle (10) to start by energizing a starter motor (40), whereby the generator (42) is driven by the ICE (18) after the vehicle (10) has been started; then to instruct the generator (42) to increase the RVC voltage supplied to the vehicle battery (14) in order to raise the voltage of the vehicle battery (14) to the neutral discharge target voltage for a third period of time, the third period being shorter than the first period of time; then to instruct the generator (42) to reduce the RVC voltage supplied to the vehicle battery (14) in order to increase a discharge current of the vehicle battery (14) to the regular discharge target current for the first time period; and then to instruct the generator (42) to perform at least a minimum number of charge cycles to charge and discharge the vehicle battery (14) based on a regulator voltage control (RVC), wherein the charging and discharging of the vehicle battery (14) generates a balance between a charge capacity and a discharge capacity of the vehicle battery (14). [2] System according to claim 1, wherein the one or more controllers (30) execute the charging cycle by: Determining the battery temperature of the vehicle battery (14); and comparing the battery temperature with a target battery temperature range. [3] System according to claim 1, wherein the one or more controllers (30) execute instructions to: to compare the state of charge of the vehicle battery (14) with a lowest value of the target state of charge range; and In response to determining that the state of charge of the vehicle battery (14) is equal to or less than the lowest value of the target state of charge range, a voltage of the vehicle battery (14) is compared with a threshold resting voltage, wherein the threshold resting voltage indicates that a replacement of the vehicle battery (14) is required.

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