Method and device for determining the charge that can be drawn from an energy accumulator

• US 20060145702A1
• Filed: 09/29/2003
• Published: 07/06/2006
• Est. Priority Date: 01/20/2003
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schoch, Eberhard
• Granted Patent: US 7,701,174 B2
• Time in Patent Office: Days
• US Class Current: 324/429
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables

Abstract

A device for ascertaining the charge able to be drawn from an energy store, in particular a battery, up to a specified cutoff, is provided. A particularly precise charge prediction may be achieved if a mathematical energy store model is used, which mathematically represents the electrical properties of the energy store and with the aid of which a charge predictor calculates the charge able to be drawn in the case of a specified discharge current. The charge predictor is connected with an estimator for a state variable and parameter, which estimator ascertains state variables and/or parameters for the mathematical energy store model from current operating performance quantities of the energy store.

Claims

1-10. -10. (canceled)

11. A device for ascertaining an amount of charge that is able to be drawn from an energy storage unit, up to at least one specified cutoff threshold, comprising:

a charge predictor for calculating, in the case of a specified discharge current characteristic, the amount of charge that is able to be drawn from the energy storage unit, on the basis of a mathematical energy storage model that mathematically represents electrical properties of the energy storage unit; and

an estimator for ascertaining at least one of state variables and parameters for the mathematical energy storage model, based on operating performance quantities of the energy storage unit.

12. The device as recited in claim 11, wherein the energy storage unit is a battery, and wherein the mathematical energy storage model is a battery model that includes at least a mathematical model for an internal resistance, an acid diffusion resistance, and a charge transfer polarization.

13. The device as recited in claim 12, wherein the estimator ascertains at least an open-circuit voltage and a concentration polarization as the state variables.

14. The device as recited in claim 13, wherein the estimator additionally ascertains a charge transfer polarization.

15. The device as recited in claim 12, wherein the charge predictor ascertains an amount of charge that is able to be drawn until a specified minimum electrolyte voltage that represents a first cutoff criterion is reached.

16. The device as recited in claim 15, wherein the charge predictor ascertains an amount of charge that is able to be drawn until a specified minimum voltage of the energy storage unit that represents a second cutoff criterion is reached.

17. The device as recited in claim 16, wherein the charge predictor ascertains an amount of charge that is able to be drawn until a specified minimum capacity that represents a third cutoff criterion is reached.

18. The device as recited in claim 12, further comprising:

a voltage predictor for ascertaining, as a function of a load current characteristic that is specified, a corresponding load voltage that arises on the basis of the specified load current characteristic.

19. A method for ascertaining an amount of charge that is able to be drawn from an energy storage unit, up to at least one specified cutoff threshold, comprising:

calculating, using a charge predictor, in the case of a specified discharge current characteristic, the amount of charge that is able to be drawn from the energy storage unit, on the basis of a mathematical energy storage model that mathematically represents electrical properties of the energy storage unit, wherein the energy storage unit is a battery; and

ascertaining, using an estimator, at least one of state variables and parameters for the mathematical energy storage model, based on operating performance quantities of the energy storage unit.

20. The method as recited in claim 19, wherein the charge predictor calculates an amount of charge that is able to be drawn until a specified minimum capacity that represents a cutoff criterion is reached, and wherein the charge predictor takes into account a load voltage supplied to the charge predictor by a voltage predictor, the voltage predictor ascertaining the load voltage as a function of a specified load current characteristic.