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

Abstract

A system for charging and discharging a vehicle battery in a vehicle. In some embodiments, the vehicle may receive at least a portion of power from an internal combustion engine (ICE) connected to a generator, or, in an alternative, the vehicle receives all power from one or more electric motors powered by a traction battery pack that is in electronic communication with an auxiliary power module (APM). The system charges and discharges the vehicle battery based on a comparison between a state of charge of the vehicle battery and a target state of charge range of the vehicle battery. Charging and discharging a vehicle battery establishes a balance between a charge capacity and a discharge capacity of the vehicle battery.

Description

Technical Field

[0001] This disclosure relates to a system for charging and discharging a vehicle battery based on the vehicle battery's state of charge (SOC). In one embodiment, the vehicle receives at least a portion of its power from an internal combustion engine (ICE). In an alternative embodiment, the vehicle is an all-electric vehicle (EV). Background Technology

[0002] Starting, lighting, and ignition (SLI) batteries, also known as vehicle batteries or auxiliary batteries, are rechargeable batteries used to supply current to the starter motor to start the vehicle's internal combustion engine. Vehicle batteries also power various electrical components in the vehicle, such as the headlights and taillights, climate control systems, and radio. In addition to traction battery packs, some electric vehicles (EVs) also include vehicle batteries. When used in electric vehicles, vehicle batteries can be referred to as auxiliary batteries.

[0003] Vehicle batteries can face many challenges. For example, a start-stop internal combustion engine automatically shuts off when the vehicle is idling and restarts when the driver's foot leaves the brake pedal. When the start-stop engine is off, the vehicle relies on its battery, rather than its alternator, to provide the electrical power needed for its electrical loads, which results in the battery undergoing significantly more discharge cycles.

[0004] Another challenge vehicle batteries may face is sulfation. Sulfation refers to the formation or accumulation of lead sulfate crystals on and within the pores of the lead plates in a lead-acid battery. If left unchecked, these crystals can continue to grow and harden over time, potentially hindering the battery's charging and discharging capabilities. The state of charge (SOC) of a vehicle battery is expressed as the ratio of its available capacity to the maximum possible amount of electricity it can store. A vehicle battery's capacity and ability to retain charge decrease over time. Therefore, even under the same charging conditions, older vehicle batteries will have a lower SOC capacity and lower charge retention capacity compared to new, equivalent batteries.

[0005] Therefore, while current vehicle batteries have achieved their intended purpose, there is still a need in the art for an improved method for charging and discharging vehicle batteries. Summary of the Invention

[0006] According to several aspects, a system for charging and discharging a vehicle battery in a vehicle is disclosed, wherein the vehicle receives at least a portion of power from an internal combustion engine (ICE) driving a generator. The system includes one or more controllers in electronic communication with the vehicle battery and the generator, wherein the one or more controllers include one or more processors that execute instructions to determine the state of charge (SOC) of the vehicle battery. The one or more controllers compare the SOC of the vehicle battery with a target SOC range for the vehicle battery. In response to determining that the SOC of the vehicle battery falls within the target SOC range, the one or more controllers instruct the vehicle battery to discharge at a conventional discharge target current for a first time period while maintaining the voltage of the vehicle battery at a conventional discharge target voltage. The one or more controllers instruct the vehicle battery to discharge at a neutral discharge target current for a second time period at a neutral discharge target voltage, wherein the second time period is shorter than the first time period. The one or more controllers instruct the vehicle to start, wherein the generator is driven by the ICE when the vehicle starts. The one or more controllers instruct the generator to perform at least a minimum number of charging cycles to charge and discharge the vehicle battery based on a regulator voltage control (RVC) voltage, wherein the charging and discharging of the vehicle battery establishes a balance between the charging capacity and the discharging capacity of the vehicle battery.

[0007] On the other hand, one or more controllers perform a charging cycle by instructing the generator to increase the RVC voltage supplied to the vehicle battery to continuously raise the voltage of the vehicle battery to the neutral discharge target voltage for a third time period, wherein the third time period is shorter than the first time period.

[0008] On the other hand, one or more controllers perform a charging cycle by instructing the generator to reduce the RVC voltage supplied to the vehicle battery to continuously increase the discharge current of the vehicle battery to the normal discharge target current for a first period of time.

[0009] On one hand, one or more controllers perform a charging cycle by determining the battery temperature of the vehicle battery and comparing that battery temperature with a target battery temperature range.

[0010] On the other hand, one or more controllers, in response to determining that the battery temperature is within a target battery temperature range, instruct the generator to perform pulse charging of the vehicle battery by increasing the RVC voltage supplied to the vehicle battery at a rate limited by the generator's conversion rate. Pulse charging includes: starting the RVC voltage with a neutral charging target voltage, increasing the RVC voltage to the maximum charging voltage of the vehicle battery, and maintaining the RVC voltage at the maximum charging voltage of the vehicle battery for a fourth time period.

[0011] On another front, the maximum charging voltage of the vehicle battery is adjusted based on battery temperature, and the temperature-adjusted maximum charging voltage is expressed as follows:

[0012] Maximum charging voltage for temperature regulation = Vstd + (25 – Tt) * 0.003 * 6

[0013] Where Tt represents the actual temperature of the vehicle battery, and Vstd is the standard maximum charging voltage of the vehicle battery during pulse charging.

[0014] On one hand, one or more controllers, in response to determining that the battery temperature falls outside a target battery temperature range, instruct the generator to perform a pulse charge on the vehicle battery by increasing the RVC voltage supplied to the vehicle battery at a rate limited by the generator's conversion rate. The pulse charge includes: starting the RVC voltage with a neutral charging target voltage, increasing the RVC voltage to a maximum temperature regulation voltage based on the battery temperature, wherein the maximum temperature regulation voltage of the vehicle battery is a function of the battery temperature, and maintaining the RVC voltage at the maximum temperature regulation voltage of the vehicle battery for a fourth time period.

[0015] On the other hand, under the adjusted maximum charging voltage, the maximum temperature regulation voltage of the vehicle battery 14 is 0.003 volts / cell, and the adjusted maximum charging voltage is expressed as:

[0016] Vadjust=Vstd+(25–Tt)*0.003*6

[0017] Where Vadjust represents the maximum adjusted charging voltage, Tt represents the actual temperature of the vehicle battery, and Vstd represents the standard maximum charging voltage of the vehicle battery during pulse charging.

[0018] On another front, one or more controllers execute a charging cycle by instructing the generator to reduce the RVC voltage to a neutral charging target voltage to charge the vehicle for a fifth time period, wherein the first, second, third, fourth, and fifth time periods are each selected such that the total charging time required for the vehicle battery is a predetermined percentage of the total vehicle operating time.

[0019] On one hand, one or more controllers execute instructions to compare the state of charge of the vehicle battery with the lowest value of a 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, compare the voltage of the vehicle battery with a threshold quiescent voltage, wherein the threshold quiescent voltage indicates that the vehicle battery needs to be replaced.

[0020] On the other hand, the vehicle battery is a 12-volt DC battery with a normal discharge target current of approximately 0.25C20 and a normal discharge target voltage of no less than approximately 11.5 volts.

[0021] In one aspect, a method for charging and discharging a vehicle battery in a vehicle is disclosed, wherein the vehicle receives at least a portion of power from an ICE driving a generator. The method includes determining the state of charge (SOC) of the vehicle battery by one or more controllers, wherein the one or more controllers are in electronic communication with the vehicle battery and the generator. The method includes comparing the SOC of the vehicle battery with a target SOC range via the one or more controllers. In response to determining that the SOC of the vehicle battery falls within the target SOC range, the method includes instructing the vehicle battery to discharge at a conventional discharge target current for a first time period while maintaining the voltage of the vehicle battery at a conventional discharge target voltage. The method includes instructing the vehicle battery to discharge at a neutral discharge target current for a second time period at a neutral discharge target voltage, wherein the second time period is shorter than the first time period. The method includes instructing the vehicle to start by the one or more controllers, wherein the generator is driven by the ICE when the vehicle is started. Finally, the method includes instructing the generator to perform at least a minimum number of charging cycles to charge and discharge the vehicle battery by the one or more controllers controlling the RVC voltage based on the regulator voltage, wherein the charging and discharging of the vehicle battery establishes a balance between the charging capacity and the discharging capacity of the vehicle battery.

[0022] On the other hand, a system for charging and discharging a vehicle battery in a vehicle is disclosed, wherein the vehicle receives all power from one or more electric motors powered by a traction battery pack electronically communicating with an auxiliary power module (APM). The system includes one or more controllers electronically communicating 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 (SOC) of the vehicle battery by the one or more controllers. The one or more controllers compare the SOC of the vehicle battery with a target SOC range for the vehicle battery. In response to determining that the SOC of the vehicle battery falls within the target SOC range, the one or more controllers instruct the vehicle battery to discharge at an initial discharge target current for a first time period while maintaining the vehicle battery voltage at a conventional discharge target voltage. The one or more controllers instruct the vehicle to start, wherein the APM provides an APM voltage to the vehicle battery upon vehicle start-up. The one or more controllers instruct the APM to perform at least a minimum number of charging cycles to charge and discharge the vehicle battery based on the APM voltage, wherein the charging and discharging of the vehicle battery achieves a balance between the charging capacity and the discharging capacity of the vehicle battery.

[0023] On the other hand, one or more controllers perform a charging cycle by instructing the APM to reduce the APM voltage supplied to the vehicle battery for a second period of time to reduce the voltage of the vehicle battery to a normal discharge target voltage, wherein the second period of time is longer than the first period of time.

[0024] On the other hand, one or more controllers perform a charging cycle by determining the battery temperature of the vehicle battery and comparing that battery temperature with a target battery temperature range.

[0025] In one aspect, one or more controllers, in response to determining that the battery temperature is within a target battery temperature range, instruct the APM to perform a pulse charge on the vehicle battery by increasing the APM voltage supplied to the vehicle battery at a rate limited by the APM's conversion rate. The pulse charge includes: starting the APM voltage with a neutral charging target voltage, increasing the APM voltage to the maximum charging voltage of the vehicle battery, and maintaining the APM voltage at the maximum charging voltage of the vehicle battery for a fourth time period.

[0026] On the other hand, one or more controllers, in response to determining that the battery temperature falls outside a target battery temperature range, instruct the APM to perform a pulse charge on the vehicle battery by increasing the APM voltage supplied to the vehicle battery at a rate limited by the APM's conversion rate. The pulse charge includes: starting the APM voltage with a neutral charging target voltage, increasing the APM voltage to a maximum temperature-regulating voltage based on the battery temperature, wherein the maximum temperature-regulating voltage of the vehicle battery is a function of the battery temperature, and maintaining the APM voltage at the maximum temperature-regulating voltage of the vehicle battery for a third time period.

[0027] On another front, under the adjusted maximum charging voltage, the maximum temperature regulation voltage of the vehicle battery 14 is 0.003 volts / cell, and the adjusted maximum charging voltage is expressed as:

[0028] Vadjust=Vstd+(25–Tt)*0.003*6

[0029] Where Vadjust represents the maximum adjusted charging voltage, Tt represents the actual temperature of the vehicle battery, and Vstd represents the standard maximum charging voltage of the vehicle battery during pulse charging.

[0030] On one hand, one or more controllers perform a charging cycle by instructing the APM to reduce the APM voltage to the neutral charging target voltage to continuously charge the vehicle battery for a fourth time period.

[0031] On the other hand, one or more controllers perform a charging cycle by instructing the APM to reduce the APM voltage to a normal discharge target voltage, wherein the vehicle battery continuously discharges at a neutral discharge target current for a fifth time period, wherein the first, second, third, fourth and fifth time periods are each selected such that the total charging time required for the vehicle battery is a predetermined percentage of the total vehicle operating time.

[0032] Further areas of application will become apparent from the description provided herein. It should be understood that these descriptions and specific examples are for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0033] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way.

[0034] Figure 1A This is a schematic diagram of a system in a vehicle disclosed according to an exemplary embodiment, the system receiving at least a portion of the power of an internal combustion engine (ICE), wherein the system includes one or more controllers in communication with the vehicle's battery electronics;

[0035] Figure 1B This is a schematic diagram of a system in an all-electric vehicle (EV) disclosed according to an exemplary embodiment;

[0036] Figure 2 This illustrates, according to an exemplary embodiment, when the vehicle receives at least a portion of the power from the ICE... Figure 1A The flowchart shown illustrates the process of charging and discharging a vehicle battery using the system shown; and

[0037] Figure 3 This illustrates, according to an exemplary embodiment, when the vehicle is an EV, ... Figure 1B The diagram shows the process flow of the system for charging and discharging vehicle batteries. Detailed Implementation

[0038] The following description is merely exemplary in nature and is not intended to limit this disclosure, its application, or its uses.

[0039] refer to Figure 1AAn exemplary vehicle 10 is shown, including the disclosed battery charging system 12 for charging and discharging the vehicle battery 14. It should be understood that the vehicle battery 14 may also be referred to as a starting, lighting, and ignition (SLI) battery. The vehicle battery 14 is a rechargeable battery used to start the vehicle 10 and provide power to one or more electrical accessories 16 that are part of the vehicle 10, such as, but not limited to, headlights, taillights, and a radio or audio system. It should be understood that the vehicle 10 can be any type of vehicle, such as, but not limited to, a sedan, truck, SUV, van, or motorhome. Figure 1A In the illustrated embodiment, vehicle 10 receives at least a portion of the power from internal combustion engine (ICE) 18, and vehicle 10 is an ICE vehicle or a hybrid electric vehicle (HEV). In such... Figure 1B In the alternative embodiment shown, vehicle 10 is an all-electric vehicle (EV) that receives all power from one or more electric motors 20 powered by a traction battery pack 22.

[0040] refer to Figure 1A and Figure 1B The two figures show a battery charging system 12 including a vehicle battery 14 and one or more controllers 30 in electronic communication with the vehicle battery 14. The one or more controllers 30 are in electronic communication 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 state-of-charge sensor 36 is omitted, and the one or more controllers 30 determine the state of charge based on the voltage of the vehicle battery 14.

[0041] like Figure 1A As shown, when vehicle 10 includes ICE 18, vehicle battery 14 is electrically connected to starter motor 40 and alternator 42. Vehicle battery 14 supplies current to starter motor 40 to crank ICE 18 during startup. During vehicle 10 startup, alternator 42 is driven by crankshaft (not shown) of ICE 18. Alternator 42 includes a conversion rate, which indicates the maximum rate of change of the output voltage or output current of alternator 42 per unit time. Alternator 42 supplies regulator voltage control (RVC) voltage to vehicle battery 14, wherein the RVC voltage is the output voltage of alternator 42 regulated based on the battery temperature of vehicle battery 14. When the RVC voltage is less than the voltage of vehicle battery 14, vehicle battery 14 discharges and supplies power to one or more electrical components 16 that are part of vehicle 10.

[0042] refer to Figure 1B When vehicle 10 receives all power from one or more electric motors 20 powered by traction battery pack 22, one or more controllers 30 are in electronic communication with traction battery pack 22 and auxiliary power module (APM) 44. APM 44 includes a conversion rate, which indicates the maximum rate of change of the output voltage or output current of APM 44 per unit time. APM 44 communicates electronically with traction battery pack 22 and converts the high voltage supplied by traction battery pack 22 into a regulated voltage, referred to as APM voltage. APM voltage is supplied to vehicle battery 14, wherein APM voltage is regulated based on the battery temperature of vehicle battery 14. When APM voltage is lower than the voltage of vehicle battery 14, vehicle battery 14 discharges and supplies power to one or more electrical components 16 that are part of vehicle 10.

[0043] A method for charging and discharging the vehicle battery 14 based on its state of charge and battery temperature will now be described. Figure 2 This is a flowchart illustrating a method 200 for charging and discharging a vehicle battery 14, where the vehicle 10 is an ICE vehicle or a HEV. It should be understood that method 200 establishes a balance between the charging capacity and 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 lifespan. When the charging capacity and 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 70% to approximately 90%.

[0044] Overall reference Figure 1A and Figure 2 Method 200 may begin at block 202. In block 202, one or more controllers 30 determine the state of charge of the vehicle battery 14 based on one or more voltage sensors 32 or one or more state of charge sensors 36. It should be understood that the state of charge of the vehicle battery 14 is determined starting on the day prior to the start of the ICE 18. Method 200 may then proceed to decision block 204.

[0045] In decision block 204, one or more controllers 30 compare the state of charge of vehicle battery 14 with a target state of charge range for vehicle battery 14. In response to determining that the state of charge of vehicle battery 14 falls outside the target state of charge range, method 200 may then proceed to decision block 206. Otherwise, method 200 may proceed to block 216.

[0046] In decision block 206, one or more controllers 30 compare the state of charge of vehicle battery 14 with the lowest value of a target state of charge range to determine whether the state of charge of vehicle battery 14 is equal to or less than the lowest value of the target state of charge range. In response to determining that the state of charge of vehicle battery 14 is greater than the highest value of the target state of charge range, method 200 may proceed to block 208.

[0047] In block 208, 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, one or more controllers 30 successively execute blocks 216, 218, 220, 222, 224, and 232 of method 200 until the state of charge of the vehicle battery 14 falls within the target state of charge range (skipping blocks 226, 228, and 230). Once the target state of charge of the vehicle battery 14 falls within the target state of charge range, the method can continue to blocks 216-232 as described below.

[0048] Returning to decision box 206, in response to determining that the state of charge of vehicle battery 14 is equal to or less than the minimum value of the target state of charge range, method 200 may proceed to decision box 210. In decision box 210, one or more controllers 30 compare the voltage of vehicle battery 14 with a threshold quiescent voltage to determine whether the voltage of vehicle battery 14 is less than the threshold quiescent voltage. The threshold quiescent voltage indicates that vehicle battery 14 needs to be replaced. By way of example only, in one embodiment, when vehicle battery 14 is a 12-volt battery, the threshold quiescent voltage is approximately 11.8 volts. In response to determining that the voltage of vehicle battery 14 is less than the threshold quiescent voltage, the method proceeds to box 212, and vehicle battery 14 is replaced, and method 200 terminates. In response to determining that the voltage of vehicle battery 14 is equal to or greater than the threshold quiescent voltage, the method proceeds to box 214.

[0049] In block 214, method 200 can then proceed to block 216. In block 216, one or more controllers 30 first execute blocks 216 through 232, and then execute charging cycle 234 (while omitting block 224) to charge and discharge the vehicle battery 14 based on the RVC voltage. Each charging cycle 234 in Figure 2 The processing flow diagram shown is described in blocks 222-232. One or more controllers 30 continue to execute charging cycle 234 until the vehicle battery 14 is in the target charging state.

[0050] Returning to reference block 204, in response to determining that the state of charge of vehicle battery 14 falls within a target state of charge range, method 200 proceeds to block 216. In block 216, one or more controllers 30 instruct vehicle battery 14 to continuously discharge at a conventional discharge target current for a first time period A, while maintaining the voltage of vehicle battery 14 at a conventional discharge target voltage. In one embodiment, vehicle battery 14 is a 12-volt DC battery, the conventional discharge target current is approximately 0.25C20, the conventional discharge target voltage is not less than approximately 11.5 volts, and the first time period A is approximately 11 seconds. It should be understood that the conventional discharge target voltage may vary based on the temperature of vehicle battery 14. Method 200 can then proceed to block 218.

[0051] In block 218, one or more controllers 30 instruct the vehicle battery 14 to discharge at a neutral discharge target current for a second time period B at a neutral discharge target voltage. It should be understood that the second time period B is shorter than the first time period A. In an embodiment where the vehicle battery 14 is a 12-volt DC battery, the neutral discharge target current is approximately 0.05C20, the second time period B is approximately 5 seconds, and the neutral discharge target voltage is at least approximately 12.3 volts. It should be understood that the neutral discharge target voltage may vary based on the temperature and state of charge of the vehicle battery 14. Method 200 can then proceed to block 220.

[0052] In block 220, one or more controllers 30 instruct vehicle 10 to start, wherein vehicle 10 is started by supplying current to starter motor 40. When vehicle 10 starts, generator 42 is driven by ICE 18. Method 200 can then proceed to block 222.

[0053] In block 222, one or more controllers 30 may then instruct generator 42 to perform at least a minimum number of charging cycles 234 based on RVC voltage to charge and discharge vehicle battery 14, wherein each charging cycle 234 is performed in [the specified range]. Figure 2 As described in blocks 222-232 of the flowchart, the minimum number of charging cycles 234 is six. Each charging cycle 234 includes raising the RVC voltage supplied to the vehicle battery 14 by the generator 42 to a neutral discharge target voltage as described in block 218 for a third time period C, lowering the RVC voltage of the vehicle battery 14 to a normal discharge target voltage as described in block 216 for a first time period A, and performing pulse charging, wherein the RVC voltage is adjusted based on the conversion rate of the generator 42. Specifically, in block 222, one or more controllers 30 instruct the generator 42 to raise the RVC voltage supplied to the vehicle battery 14 to the neutral discharge target voltage for a third time period C, wherein the third time period is shorter than the first time period A. In one embodiment, the third time period is approximately five seconds. Method 200 can then proceed to block 224.

[0054] In block 224, one or more controllers 30 instruct generator 42 to reduce the RVC voltage supplied to vehicle battery 14 to continuously increase the discharge current of vehicle battery 14 to a normal discharge target current for a first time period A. Method 200 can then proceed to decision block 226.

[0055] In decision block 226, one or more controllers 30 monitor 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 to a target battery temperature range. In response to determining that the battery temperature falls within the target battery temperature range, method 200 may proceed to block 228. Otherwise, the method proceeds to block 230. In a non-limiting embodiment, the target battery temperature range is approximately 25°C + / - 5°C. It should be understood that the maximum charging voltage of the vehicle battery 14 is 15.7 volts.

[0056] In block 228, 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 conversion rate of the generator 42. The pulse charging includes starting the RVC voltage with a neutral charging target voltage, increasing the RVC voltage to the 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 period D. The neutral charging target voltage is greater than the open-circuit voltage (OCV) of the vehicle battery 14 in the target charging state. In one embodiment, the neutral charging target voltage is 0.13 volts greater than the open-circuit voltage (OCV) of the vehicle battery 14 in the target charging state, wherein the neutral charging target voltage is a fixed value for all values ​​of the charging state. In an embodiment where the vehicle battery 14 is a 12-volt battery, the maximum charging voltage of the vehicle battery 14 during standard operating conditions is 15.7 volts at 25°C + / - 5°C. It should be understood that the maximum charging voltage of the vehicle battery 14 is limited based on accepting a system load of no more than 16 volts. It should also be understood that the maximum charging voltage of the vehicle battery 14 can be adjusted based on the temperature of the vehicle battery 14. In one embodiment, the temperature-adjusted 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 the 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 vehicle requirements. The fourth time period D is less than the first time period A. In this embodiment, the fourth time period D is approximately four seconds.

[0057] Returning to reference decision box 226, in response to determining that the battery temperature falls outside the target battery temperature range, method 200 can proceed to box 230. In box 230, 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 by the conversion rate of the generator 42. The pulse charging includes starting the RVC voltage at a neutral charging target voltage, increasing the RVC voltage to a maximum temperature-regulated voltage based on the battery temperature, and maintaining the RVC voltage at the maximum temperature-regulated voltage of the vehicle battery 14 for a fourth time period D. The maximum temperature-regulated voltage of the vehicle battery 14 is a function of the temperature of the vehicle battery 14. In one embodiment, the maximum temperature-regulating voltage of the vehicle battery 14 is 0.003 volts / cell at the adjusted maximum charging voltage Vadjust, where Vadjust = Vstd + (25 - Tt) * 0.003 * 6, where Vstd represents the standard maximum charging voltage of the vehicle battery 14 during pulse charging, and Tt represents the actual temperature of the vehicle battery 14, where the actual temperature Tt is either less than 20°C or greater than 30°C. The adjusted maximum charging voltage Vadjust does not exceed 15.2 volts at the highest operating temperature of the vehicle battery 14 and does not exceed 16 volts at the lowest operating temperature of the vehicle battery 14. Alternatively, the maximum temperature-regulating voltage is based on the manufacturer's specifications. In one embodiment, the maximum temperature-regulating voltage may also be limited based on vehicle requirements during certain operating conditions (e.g., when the vehicle's high beams are also on). Figure 2 As shown, boxes 228 and 230 can then proceed to box 232.

[0058] In block 232, one or more controllers 30 instruct generator 42 to reduce the RVC voltage to a neutral charging target voltage to charge vehicle 10 for a continuous fifth time period E. The fifth time period E is shorter than the first time period A. In an embodiment, the fifth time period E is approximately seven seconds. Method 200 can then return to blocks 202, 204, 216, or 222 to perform another charging cycle 234. Alternatively, method 200 can terminate if vehicle battery 14 has already undergone the minimum number of charging cycles 234.

[0059] It should be understood that the first time period A, the second time period B, the third time period C, the fourth time period D, and the fifth time period E are each selected such that the total charging time required 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).

[0060] Figure 3This is a process flow diagram illustrating a method 300 for charging and discharging a vehicle battery 14, wherein the vehicle 10 is an EV that receives all its power from one or more electric motors 20 powered by a traction battery pack 22. (See overall reference) Figure 1B and Figure 3 Method 300 may begin at block 302. In block 302, one or more controllers 30 determine the state of charge of the vehicle battery 14 based on one or more voltage sensors 32 or one or more state of charge sensors 36. Method 300 may then proceed to decision block 304.

[0061] In decision block 304, one or more controllers 30 compare the state of charge of vehicle battery 14 with a target state of charge range for vehicle battery 14. In response to determining that the state of charge of vehicle battery 14 falls outside the target state of charge range, method 300 may then proceed to decision block 306. Otherwise, method 300 may proceed to block 316.

[0062] In decision block 306, one or more controllers 30 compare the state of charge of vehicle battery 14 with the lowest value of a target state of charge range to determine whether the state of charge of vehicle battery 14 is equal to or less than the target state of charge. In response to determining that the state of charge of vehicle battery 14 is equal to or greater than the highest value of the target state of charge range, method 300 may proceed to block 308.

[0063] 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, one or more controllers 30 successively execute blocks 316, 318, 320, 328, and 330 of method 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 state of charge of the vehicle battery 14 falls within the target state of charge range, method 300 may continue to blocks 316-330, as described below.

[0064] Returning to decision box 306, in response to determining that the state of charge of vehicle battery 14 is less than the minimum value of the target state of charge range, method 300 may proceed to decision box 310. In box 310, one or more controllers 30 compare the voltage of vehicle battery 14 with a threshold resting voltage. In response to determining that the voltage of vehicle battery 14 is less than the threshold resting voltage, the method proceeds to box 312, and vehicle battery 14 is replaced, and method 300 terminates. In response to determining that the voltage of vehicle battery 14 is equal to or greater than the threshold resting voltage, the method proceeds to box 314.

[0065] In block 314, one or more controllers 30 discharge the vehicle battery 14 with an initial discharge target current for a first time period A2 as described in block 316, and then proceed to block 318. Then, one or more controllers 30 may continuously execute 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.

[0066] Returning to reference decision box 304, in response to determining that the state of charge of vehicle battery 14 falls within the target state of charge range, method 300 proceeds to box 316. In box 316, one or more controllers 30 instruct vehicle battery 14 to discharge continuously for a first time period A2 at an initial discharge target current while maintaining the voltage of vehicle battery 14 at a normal discharge target voltage. The initial discharge target current is based on the current required by vehicle 10. In an embodiment, the first time period A2 is approximately ten seconds, and the initial discharge target current is approximately 0.25C20. Method 300 can then proceed to box 318.

[0067] In block 318, one or more controllers 30 instruct vehicle 10 to start. Traction battery pack 22 provides power to one or more electric motors 20, and APM 44 provides APM voltage to vehicle battery 14 when vehicle 10 starts. Method 300 can then proceed to block 320.

[0068] In block 320, one or more controllers 30 can then instruct the APM 44 to perform at least a minimum number of charging cycles 332 based on the APM voltage to charge and discharge the vehicle battery 14, wherein each charging cycle 332 is performed in... Figure 3 The process flow diagram is described in blocks 320-330. Specifically, in block 320, one or more controllers 30 instruct the APM 44 to reduce the APM voltage supplied to the vehicle battery 14 for a second time period B2, reducing the voltage of the vehicle battery 14 to a conventional discharge target voltage of not less than approximately 11.5 volts. In an embodiment, the second time period B is approximately thirteen seconds, and the second time period B2 is longer than the first time period A2. Method 300 can then proceed to decision block 322.

[0069] In decision block 322, one or more controllers 30 monitor 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 to a target battery temperature range. In response to determining that the battery temperature falls within the target battery temperature range, method 300 may proceed to block 324. Otherwise, the method proceeds to block 326.

[0070] In block 324, 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 by the conversion rate of the APM 44. The pulse charging includes initially bringing the APM voltage to a neutral charging 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 period C2. The third time period C2 is shorter than the first time period A2 and the second time period B2. In an embodiment, the third time period C2 is approximately three seconds.

[0071] Returning to reference decision box 322, in response to determining that the battery temperature falls outside the target battery temperature range, method 300 can proceed to box 326. In box 326, 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 by the conversion rate of the APM 44. The pulse charging includes starting the APM voltage with a neutral charging target voltage, increasing the APM voltage to a maximum temperature-regulated voltage based on the battery temperature, and maintaining the APM voltage at the maximum temperature-regulated voltage of the vehicle battery 14 for a third time period C2. The maximum temperature-regulated voltage of the vehicle battery 14 is calculated based on the method described in box 230 above. Figure 3 As shown, boxes 324 and 326 can then proceed to box 328.

[0072] In block 328, one or more controllers 30 instruct the APM 44 to reduce the APM voltage to a neutral charging target voltage to continuously charge the vehicle battery 14 for a fourth time period D2. The fourth time period D2 is shorter than the first time period A2 and the second time period B2. In an embodiment, the fourth time period D2 is approximately eight seconds. Method 300 can then proceed to block 330.

[0073] In block 330, one or more controllers 30 instruct the APM 44 to reduce the APM voltage to a normal discharge target voltage, and the vehicle battery 14 continues to discharge at a neutral discharge target current for a fifth time period E2. The fifth time period E2 is less than the first time period A2 and the second time period B2. In an embodiment, the fifth time period E2 is approximately seven seconds. Method 300 can then return to block 320 to perform another charging cycle 332. Alternatively, method 300 can terminate if the vehicle battery 14 has already undergone the minimum number of charging cycles 332.

[0074] Referring generally to the accompanying drawings, the disclosed system for charging and discharging vehicle batteries offers various technical effects and benefits. Specifically, the system can improve the state of charge of the vehicle battery during operation, improve fuel economy, establish a balance between the charging and discharging capacity of the vehicle battery, and maintain the vehicle battery within a target state of charge range until the end of its service life. Furthermore, the disclosed system can remove sulfates from the lead plates of lead-acid batteries before crystallization to prevent or reduce battery sulfation.

[0075] A controller can refer to electronic circuitry, combinational logic circuitry, a field-programmable gate array (FPGA), a processor (shared, dedicated, or grouped) that executes code, or a combination of some or all of the above, or a portion of the aforementioned electronic circuitry, combinational logic circuitry, or FPGA, such as in a system-on-a-chip. Alternatively, the controller can be microprocessor-based, such as a computer having at least one processor, memory (RAM and / or ROM), and associated input and output buses. The processor can operate under the control of an operating system residing in memory. The operating system can manage computer resources such that computer program code embodied as one or more computer software applications (e.g., applications residing in memory) can have instructions that are executed by the processor. In alternative embodiments, the processor can directly execute the application, in which case the operating system can be omitted.

[0076] The descriptions in this disclosure are merely exemplary in nature, and changes that do not depart from the spirit and scope of this disclosure are intended to fall within its scope. Such changes should not be considered as departing from the spirit and scope of this disclosure.

Claims

1. A system for charging and discharging a vehicle battery in a vehicle, wherein, The vehicle receives at least a portion of the power from an internal combustion engine (ICE) that drives a generator, and the system includes: One or more controllers that communicate electronically with the vehicle battery and the generator, wherein the one or more controllers include one or more processors that execute the following instructions: The state of charge of the vehicle battery is determined by one or more controllers; The state of charge of the vehicle battery is compared with the target state of charge range of the vehicle battery; In response to determining that the state of charge of the vehicle battery falls within the target state of charge range, the vehicle battery is instructed to continue discharging at a normal discharge target current for a first time period, while maintaining the voltage of the vehicle battery at a normal discharge target voltage. The vehicle battery is instructed to discharge at a neutral discharge target current for a second time period at a neutral discharge target voltage, wherein the second time period is shorter than the first time period; Instructing the vehicle to start, wherein the generator is driven by the internal combustion engine when the vehicle starts; and Based on the regulator voltage control RVC voltage, the generator is instructed to perform at least a minimum number of charging cycles to charge and discharge the vehicle battery, wherein the charging and discharging of the vehicle battery establishes a balance between the charging capacity and the discharging capacity of the vehicle battery.

2. The system according to claim 1, wherein, The one or more controllers perform the charging cycle in the following manner: The generator is instructed to increase the RVC voltage supplied to the vehicle battery for a third time period to raise the voltage of the vehicle battery to the neutral discharge target voltage, wherein the third time period is shorter than the first time period.

3. The system according to claim 2, wherein, The one or more controllers execute the charging cycle in the following manner: The generator is instructed to reduce the RVC voltage supplied to the vehicle battery to continuously increase the discharge current of the vehicle battery to the normal discharge target current during the first time period.

4. The system according to claim 3, wherein, The one or more controllers execute the charging cycle in the following manner: Determine the battery temperature of the vehicle battery; and The battery temperature is compared with the target battery temperature range.

5. The system according to claim 4, wherein, The one or more controllers execute the charging cycle in the following manner: In response to determining that the battery temperature is within the target battery temperature range, the generator is instructed to pulse charge the vehicle battery by increasing the RVC voltage supplied to the vehicle battery at a rate limited by the generator's conversion rate, wherein the pulse charging includes: The RVC voltage is started with a neutral charging target voltage; Increase the RVC voltage to the maximum charging voltage of the vehicle battery; and The RVC voltage is maintained at the maximum charging voltage of the vehicle battery for a fourth consecutive time period.

6. The system according to claim 5, wherein, The maximum charging voltage of the vehicle battery is adjusted based on the battery temperature, wherein the temperature-adjusted maximum charging voltage is expressed as follows: Maximum charging voltage for temperature regulation = Vstd + (25 - Tt) * 0.003 * 6 Where Tt represents the actual temperature of the vehicle battery, and Vstd is the standard maximum charging voltage of the vehicle battery during the pulse charging.

7. The system according to claim 4, wherein, The one or more controllers execute the charging cycle in the following manner: In response to determining that the battery temperature falls outside the target battery temperature range, the generator is instructed to pulse charge the vehicle battery by increasing the RVC voltage supplied to the vehicle battery at a rate limited by the generator's conversion rate, wherein the pulse charging includes: The RVC voltage is started with a neutral charging target voltage; The RVC voltage is increased to a maximum temperature regulation voltage based on the battery temperature, wherein the maximum temperature regulation voltage of the vehicle battery is a function of the battery temperature; and The RVC voltage is maintained at the maximum temperature regulation voltage of the vehicle battery for a continuous fourth time period.

8. The system according to claim 5, wherein, At the adjusted maximum charging voltage, the maximum temperature regulation voltage of the vehicle battery 14 is 0.003 volts / cell, and wherein 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 the actual temperature of the vehicle battery, and Vstd represents the standard maximum charging voltage of the vehicle battery during the pulse charging.

9. The system according to claim 5, wherein, The one or more controllers perform the charging cycle in the following manner: The generator is instructed to reduce the RVC voltage to a neutral charging target voltage to continuously charge the vehicle for a fifth time period, wherein the first time period, the second time period, the third time period, the fourth time period, and the fifth time period are each selected such that the total charging time required for the vehicle battery is a predetermined percentage of the total vehicle operating time.

10. The system according to claim 1, wherein, The one or more controllers execute instructions to: The state of charge of the vehicle battery is compared with the lowest value of the target state of charge range; as well as In response to determining that the state of charge of the vehicle battery is equal to or less than the minimum value of the target state of charge range, the voltage of the vehicle battery is compared with a threshold quiescent voltage, wherein the threshold quiescent voltage indicates that the vehicle battery needs to be replaced.

Images