Intelligent charge limitation for high voltage batteries

Abstract

Intelligent charge limitation for high voltage battery charging provides for increased motor regeneration of an electric vehicle, and reduced application of a basic brake system of an electric vehicle. A plurality of data factors are used to calculate a maximum charge percentage. The maximum charge percentage is used to ensure sufficient charge capacity in the battery to store current generated by the motor during downhill travel. The intelligent charge limit also provides an operator of the electric vehicle with an option to change the charge limit to ensure that the battery receives the maximum current generated by the motor during downhill travel. The operator may also insert the charging gun twice such that the state-of-charge routine does not consider shifting the operator charge percentage through multiple data factors.

Description

[0001] Citation of Related Applications

[0002] This patent application claims the benefit of U.S. Patent Application No. 17 / 858,742, filed on July 6, 2022. That patent application is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention relates to limiting charging of a high voltage battery of a vehicle from an external charging source. Background Art

[0004] The charge capacity of the high voltage battery is limited to approximately 90%-98% of the state of charge (SOC), which is a calibration set by the OEM. When the battery's state of charge is full, the regeneration function of the electric motor (e-motor) cannot work because the current generated by the electric motor cannot be stored in the high voltage battery unless there is a mechanism on the vehicle to absorb this current. Therefore, the current generated by the electric motor during downhill driving is wasted because it cannot be stored in the battery. Therefore, the regenerative braking force from the electric motor cannot be used to slow down the vehicle. In addition, if there is no heat dissipation resistor hardware component to waste energy at the electric motor, the current cannot be stored in the battery and regenerative braking cannot occur. In this case, only basic braking can be used to slow down the vehicle. Electric motor regeneration typically reduces the application of basic braking.

[0005] Therefore, there is a clear need in the art to intelligently limit the charging of a high voltage battery that allows: the charging limit to be modified based on the terrain over which the vehicle is traveling; provides increased motor regeneration and reduces the number of applications of the foundation braking system; reduces the risk of regenerative braking interruptions, reduces the time and operating cost of charging from an external source, and allows the vehicle operator to change the maximum state of charge percentage. Summary of the invention

[0006] The present disclosure is an intelligent charging limit for high voltage battery charging, which provides increased motor regeneration and reduced application of the foundation brake system, reduces the risk of regenerative braking interruption, and reduces the time and operating cost of charging from an external source. The intelligent charging limit also provides the operator of an electric vehicle powered by a high voltage battery and / or a fuel cell system with the option of changing the charging limit to ensure that the battery receives the maximum amount of current generated by the motor during downhill driving. Reducing reliance on foundation braking will prevent the foundation brake system from overheating during long downhill road segments in the summer. The intelligent charging limit will also prevent regeneration interruptions caused when the battery has no more room to receive current from the motor during downhill driving. Due to the reduction in the maximum charging limit of the battery, the time spent at the charging station will be reduced. The intelligent charging limit is applicable to heavy and medium vehicles including school buses. The intelligent charging limit will not allow the charging gun to charge the battery beyond a preset maximum charge percentage, which is determined by the charging routine and / or the operator of the vehicle for the expected downhill segment in the driving route. Intelligent charging limiting includes the following advantages: reduces the risk of regeneration interruption; reduces the time spent at the charging station; maximizes the use of regenerative braking; reduces the application of foundation braking and reduces the operating cost of charging the battery; and allows the operator to change the maximum charge percentage. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a flow chart of intelligent charging limitation for a high voltage battery according to the present invention.

[0008] Figure 2 is an illustration of a vehicle about to travel on a route having multiple downhill segments.

[0009] Figure 3 is a graphical representation of upper and lower charging boundaries for intelligent charging limiting of a high voltage battery according to the present invention. DETAILED DESCRIPTION

[0010] Referring now to the drawings, and in particular to Figure 1 , a smart charge limit flow chart 10 is shown. The smart charge limit algorithm 5 receives data inputs from a horizon map 12, a road grade sensor 14, and wheel torque and vehicle speed 16. The horizon map data from the horizon map 12 will indicate whether there is a future downhill road segment. The smart charge limit algorithm 5 will determine whether the maximum charge limit should be reduced and the amount of reduction based on the data inputs from the horizon map 12, the road grade sensor 14, and the wheel torque and vehicle speed 16, and adjust the maximum charge limit accordingly. The road grade sensor 14 provides a positive or negative terrain grade. Reference Figure 2, the accumulated travel distance based on the information from the road grade sensor 14 will indicate whether the vehicle 100 is traveling on a relatively flat road surface. A flat driving route will be determined by monitoring the information from the road grade sensor 14, the vehicle speed, and using an up / down counter. A flat driving route will not result in any adjustment of the state of charge limit.

[0011] Wheel torque and vehicle speed 16 are used to calculate the energy consumption and the average percentage of energy generated through regeneration over a duty cycle based on multiple trips on highway and urban cycles, thereby calculating the state of charge limit offset using a parameter list stored in the ECU, NVM or cloud. Map state of charge limiting factor 18 is calculated based on horizon data provided by horizon map 12. Slope state of charge limiting factor 20 is calculated based on data provided by road slope sensor 14. The calculated average energy consumed and generated 22 is generated from wheel torque and vehicle speed 16. Wheel state of charge limiting factor 24 is calculated based on the average energy consumed and generated 22. Reference Figure 3 The state of charge routine 26 receives input from the map state of charge constraints 18 , the grade state of charge constraints 20 , and the wheel state of charge constraints 24 .

[0012] The map state of charge limit factor 18, the grade state of charge limit factor 20, and the wheel state of charge limit factor 24 are all dynamic offset factors that will change depending on the travel route 102. In addition, the map state of charge limit factor 18, the grade state of charge limit factor 20, and the wheel state of charge limit factor 24 are all dependent on the load of the vehicle. The electric motor of a lightly loaded vehicle will produce less current output during downhill travel than a heavily loaded vehicle. Therefore, a smaller charge limit reduction will be appropriate. Reference Figure 3 The state of charge routine 26 is also provided with preset state of charge limit upper and lower boundaries 28. Preferably there is a maximum limit state of charge percentage and a minimum limit state of charge percentage. The maximum charge limit provides the charge capacity in the high voltage battery to receive charge from regenerative braking. The minimum charge limit prevents the customer from setting the charge limit percentage too low using the customer programmable parameter 30.

[0013] refer to Figure 3, the state of charge limit routine 26 receives input from the vehicle operator through the customer programmable parameters 30. The vehicle operator is allowed to introduce a maximum charge limit based on their fixed vehicle operation route. The maximum charge limit is preferably entered through a customer programmable parameter or some type of human machine interface (HMI), which can be password protected. The fleet manager can determine which drivers can access the password. The minimum limit is protected by the OEM to prevent it from being set too low. If the customer operates on a relatively flat driving route (such as Illinois or Indiana), the maximum charge limit can be programmed to be closer to the maximum charge boundary (such as 95%). However, if the customer operates in the mountains, the state of charge limit percentage can be programmed to a lower value (such as 80%), which will leave some room for charging the high voltage battery using regenerative braking when driving downhill. The value of 80% will ensure that most of the braking will come from regeneration, rather than the basic braking system. In addition, the time spent at the charging station will be less because the customer no longer needs to wait until the high voltage battery is charged to a high percentage value above 90%. Approaching the maximum charge limit of the high-voltage battery takes longer than reaching a lower percentage limit. Therefore, charging the high-voltage battery to a lower limit will result in the customer spending less time at the charging station 104.

[0014] In order to provide flexibility and convenience to the customer, the customer programmable parameters 30 will allow the customer to override the dynamic offset factors during charging at the charging station 104. Once charging is successfully completed according to the customer programmable parameters 30, the operator needs to unplug the charging gun and plug it back in to override the dynamic offset factors 18, 20, 24. The operator can ensure that the customer programmable parameters 30 override the dynamic offset factors 18, 20, 24 generated from the horizon map 12, the road grade sensor 14, and the wheel torque and vehicle speed 16. The charging state routine 26 receives input from the map charging state limit factor 18, the grade charging state limit factor 20 and the wheel charging state limit factor 24, the preset charging state limit upper and lower boundaries 28 and the customer programmable parameters 30, and outputs a dynamically adjusted charging state limit percentage. The charging state routine 26 outputs the final maximum charging limit to the charging system 32.

[0015] While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and therefore, it is the object of the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

Claims

1. A method for providing intelligent charging limitation for a battery in a vehicle, the method comprising the following steps: using at least one of horizon map data, a road grade sensor, wheel torque, and vehicle speed, the horizon map data including data of downhill segments in a driving route, the road grade sensor providing a positive grade or a negative grade of the driving route; dynamically calculating a percentage of a maximum charge limit based on at least one of the horizon map data, the road grade sensor, wheel torque, and vehicle speed to create a dynamic maximum charge limit for the battery; providing a minimum boundary percentage charge limit and a maximum boundary percentage charge limit; and The dynamic maximum charge limit is combined with the upper boundary percentage charge limit and the lower boundary percentage charge limit to define a maximum charge limit for charging the battery.

2. The method for providing intelligent charging restriction as claimed in claim 1, further comprising the steps of: Data is input based on previous trips on the same driving route to calculate the maximum charging limit.

3. The method for providing intelligent charging restriction as claimed in claim 1, further comprising the steps of: The weight of the vehicle is used to determine the charge limit percentage.

4. A method for providing intelligent charging limitation for a battery in a vehicle, the method comprising the steps of: using at least one of horizon map data, a road grade sensor, wheel torque, and vehicle speed, the horizon map data including data of downhill segments in a driving route, the road grade sensor providing a positive grade or a negative grade of the driving route; dynamically calculating a percentage of a maximum charge limit based on at least one of the horizon map data, the road grade sensor, wheel torque, and vehicle speed to create a dynamic maximum charge limit for the battery; Enter the operator's maximum charge limit entered by the user; The operator maximum charge limit is offset by the dynamic maximum charge limit to define a maximum charge limit for charging the battery.

5. The method for providing intelligent charging restriction as claimed in claim 4, further comprising the steps of: A minimum boundary percentage charging limit and a maximum boundary percentage charging limit are provided as a reference.

6. The method for providing intelligent charging restriction as claimed in claim 5, further comprising the steps of: The maximum charge limit is calculated using the upper boundary percentage charge limit and the lower boundary percentage charge limit.

7. The method for providing intelligent charging restriction as claimed in claim 6, further comprising the steps of: The upper boundary percentage charge limit and the lower boundary percentage charge limit are input using one of a customer programmable parameter or an HMI device.

8. The method for providing intelligent charging restriction as claimed in claim 4, further comprising the steps of: Data is input based on previous trips on the same driving route to calculate the maximum charging limit.

9. The method for providing intelligent charging restriction as claimed in claim 4, further comprising the steps of: The weight of the vehicle is used to determine the charge limit percentage.

10. A method for providing intelligent charging limitation for a battery in a vehicle, the method comprising the steps of: using at least one of horizon map data, a road grade sensor, wheel torque, and vehicle speed, the horizon map data including data of downhill segments in a driving route, the road grade sensor providing a positive grade or a negative grade of the driving route; dynamically calculating a percentage of a maximum charge limit based on at least one of the horizon map data, the road grade sensor, wheel torque, and vehicle speed to create a dynamic maximum charge limit for the battery; Enter the operator's maximum charge limit entered by the user; The charging gun is reinserted at the charging station so that the dynamic maximum charging limit is not used to calculate a maximum charging limit for charging the battery.

11. The method for providing intelligent charging restriction as claimed in claim 9, further comprising the steps of: Data is entered based on previous trips on the same driving route.

12. The method for providing intelligent charging restriction as claimed in claim 11, further comprising the steps of: A minimum boundary percentage charging limit and a maximum boundary percentage charging limit are provided as a reference.

13. The method for providing intelligent charging restriction as claimed in claim 12, further comprising the steps of: The maximum charge limit is calculated using the upper boundary percentage charge limit and the lower boundary percentage charge limit.

14. The method for providing intelligent charging restriction as claimed in claim 13, further comprising the steps of: The upper boundary percentage charge limit and the lower boundary percentage charge limit are input using one of a customer programmable parameter or an HMI device.

15. The method for providing intelligent charging restriction as claimed in claim 10, further comprising the steps of: The weight of the vehicle is used to determine the charge limit percentage.

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