Method and device for determining the charge status of a battery

• US 20020101243A1
• Filed: 11/19/2001
• Published: 08/01/2002
• Est. Priority Date: 11/17/2000
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schoch, Eberhard, Mentgen, Dirk
• Granted Patent: US 6,531,874 B2
• Time in Patent Office: Days
• US Class Current: 324/427
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method of determining the charge status of a battery, in particular an automotive battery, comprising the following steps:

determining a first battery charge status soc_U0 on the basis of a measurement of the no-load voltage of the battery,

determining a second battery charge status soc_i on the basis of integration of a battery current over time, and

forming a weighted average from battery charge states soc_U0 and soc_i thus determined, to obtain an average battery charge status soc.

Claims

1. A method of determining a charge status of a battery, comprising:

determining a first battery charge status as a function of a measurement of a no-load voltage of the battery;

determining a second battery charge status as a function of an integration of a battery current over time; and

determining a weighted average from the first and second battery charge states in order to obtain an average battery charge status.

2. The method according to claim 1, wherein the battery is an automotive battery.

3. The method according to claim 1, wherein the weighted average is determined on the basis of an equation of the form:

soc=(1−

gew)*soc_i+gew*soc_U0

where gew is a weighting factor, for which the inequality 0≦

gew≦

1 holds.

4. The method according to claim 3, wherein the weighting factor is predetermined on the basis of an equation of the form:

gew=1−

exp(−

t_R/T_R)

where t_R is a duration of a prior resting phase, and T_R is a time constant of a transient response of the battery no-load voltage until it reaches a battery open-circuit voltage.

5. A device for determining a charge status of a battery, comprising:

a first arrangement for determining a first battery charge status as a function of a measurement of no-load voltage of the battery;

a second arrangement for determining a second battery charge status as a function of an integration of a battery current over time; and

a third arrangement for determining a weighted average from the first and second battery charge states in order to obtain an average battery charge status.

6. The device according to claim 5, wherein the battery is an automotive battery.