Method for resetting a state of charge fo a battery of a hybrid electric vehicle

• US 20040119441A1
• Filed: 12/18/2002
• Published: 06/24/2004
• Est. Priority Date: 12/18/2001
• Status: Active Grant

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: Koo, Jae-Seung
• Granted Patent: US 6,841,972 B2
• Time in Patent Office: Days
• US Class Current: 320/104
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60L 50/15 with additional electric power supply with capacitors charged by engine-driven generators B60L50/40; with batteries charged by engine-driven generators B60L50/61
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: H02J 7/14 for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors

Abstract

A method for resetting a state of charge of a battery for a hybrid electric vehicle comprises: determining whether a discharge current of the battery is greater than a predetermined discharge current; determining whether a minimum voltage module has changed, if the discharge current of the battery is greater than the predetermined discharge current; determining whether a theoretical discharge voltage is greater than a voltage of the minimum voltage module, if the minimum voltage module has changed; determining whether the theoretical discharge voltage remains greater than the voltage of the minimum voltage module for a predetermined period of time, if the theoretical discharge voltage is greater than the voltage of the minimum voltage module; and setting a state of charge of the battery as a very low state, if the theoretical discharge voltage remains greater than the voltage of the minimum voltage module for the predetermined period of time.

Claims

1. A method for resetting a state of charge of a battery for a hybrid electric vehicle, comprising:

determining whether a discharge current of the battery is greater than a predetermined discharge current;

determining whether a minimum voltage module has changed, if the discharge current of the battery is greater than the predetermined discharge current;

determining whether a theoretical discharge voltage is greater than a voltage of the minimum voltage module, if the minimum voltage module has changed;

determining whether the theoretical discharge voltage remains greater than the voltage of the minimum voltage module for a predetermined period of time, if the theoretical discharge voltage is greater than the voltage of the minimum voltage module; and

setting a state of charge of the battery as a very low state, if the theoretical discharge voltage remains greater than the voltage of the minimum voltage module for the predetermined period of time.

2. The method of claim 1, further comprising:

determining whether the theoretical discharge voltage is greater than an average voltage of a plurality of modules of the battery, if the theoretical discharge voltage is not greater than the voltage of the minimum voltage module;

determining whether the theoretical discharge voltage remains greater than the average voltage for a predetermined period of time, if the theoretical discharge voltage is greater than the average voltage; and

setting a state of charge of the battery as a low SOC state, if the theoretical discharge voltage remains greater than the average voltage for the predetermined period of time.

3. The method of claim 1, wherein the theoretical discharge voltage is calculated based on a voltage caused by an internal resistance and a no-load voltage.

4. A method for resetting a state of charge of a battery for a hybrid electric vehicle, comprising:

determining whether a charge current of the battery is greater than a predetermined charge current;

determining whether a maximum voltage module has changed, if the charge current of the battery is greater than the predetermined charge current;

determining whether a theoretical charge voltage is less than a voltage of the maximum voltage module, if the maximum voltage module has changed;

determining whether at the theoretical charge voltage remains less than the voltage of the maximum voltage module for a predetermined period of time, if the theoretical charge voltage is less than the voltage of the maximum voltage module; and

setting a state of charge of the battery as a very high state, if the theoretical charge voltage remains less than the voltage of the maximum voltage module for the predetermined period of time.

5. The method of claim 4, further comprising:

determining whether the theoretical charge voltage is less than an average voltage of a plurality of modules of the battery, if the theoretical charge voltage is not less than the voltage of the maximum voltage module;

determining whether the theoretical charge voltage remains less than the average voltage for a predetermined period of time, if the theoretical charge voltage is less than the average voltage; and

setting a state of charge of the battery as a high SOC state, if the theoretical charge voltage remains less than the average voltage for the predetermined period of time.

6. The method of claim 4, wherein the theoretical charge voltage is calculated based on a voltage caused by an internal resistance and a no-load voltage.

7. A method of improving accuracy of measuring a state of charge of a battery for a hybrid electric vehicle, the method comprising:

dividing a voltage of a full state of charge of the battery into a plurality of charge states, the plurality of charge states having a plurality of transition charge values defining boundaries between the charge states;

measuring a state of charge of the battery;

determining when the battery is in steady-state; and

resetting the measured state of charge of the battery to a first transition charge value when the state of charge of the battery crosses the first transition charge value of the plurality of charge values, and the battery is determined to be in steady-state.

8. The method of claim 7, wherein the plurality of charge states include at least one of a very high, high, normal, low, and very low charge states.