Method and arrangment for determination of the state of charge of a battery

• US 20030052690A1
• Filed: 10/08/2002
• Published: 03/20/2003
• Est. Priority Date: 11/17/2000
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schoch, Eberhard
• Granted Patent: US 6,943,528 B2
• Time in Patent Office: Days
• US Class Current: 324/433
• CPC Class Codes: G01R 31/3647 for determining the ability of a battery to perform a critical function, e.g. cranking
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/3835 involving only voltage measurements

Abstract

Method of determining the state of charge soc of a battery, in particular a starting battery of a motor vehicle; the state of charge being calculated, in a first operating range, on the basis of a model calculation in which a measured and a calculated battery voltage U_Batt, U_Batt′ are balanced, using feedback.

Claims

1. A method of determining the state of charge soc of a battery, in particular a starting battery of a motor vehicle,

wherein, in the presence of a first operating range of the battery, the state of charge is calculated on the basis of a model calculation, in which a measured and a calculated battery voltage U_Batt, U_Batt′

are adjusted, using feedback.

2. The method according to claim 1,

wherein the first operating range is assumed if a battery current or discharging current is greater than a minimum battery current I_Batt,min or a minimal battery current.

3. The method according to claims 1 or 2,

wherein an off-load voltage U_R from which the state of charge soc of the battery is derivable is calculated on the basis of the model calculation.

4. The method according to one of the preceding claims,

wherein the state of charge soc of the battery is calculated according to a function of the formula

soc=f(U_R)=(U_R−

U_R,min)/(U_R,max−

U_R,min).

5. The method according to one of the preceding claims,

wherein in the presence of a second operating range of the battery, the state of charge is determined on the basis of a measurement of the battery current and an off-load voltage calculated or estimated last, in particular in the presence of the first operating range.

6. Method according to one of the preceding claims,

wherein the second operating range is assumed when the battery current is less than or equal to the minimum battery current I_Batt,min.

7. An arrrangement for determining the state of charge of a battery, in particular a starting battery of a motor vehicle, characterized by a monitoring device, in particular a Kalman filter (1), which determines the state of charge of the battery by calculating an off-load voltage in a first operating range of the battery, on the basis of a model calculation in which a measured and a calculated battery voltage are balanced by feedback;

and which determines the state of charge of the battery in a second operating range, on the basis of a measurement of the battery current and an off-load voltage calculated or estimated last, in particular in the presence of the first operating range.