Method for determining a state of health of at least one electrochemical energy store

Patent metadata

Field	Value
Publication number	US-12253570-B2
Application number	US-202117788457-A
Country	US
Kind code	B2
Filing date	Feb 18, 2021
Priority date	Feb 28, 2020
Publication date	Mar 18, 2025
Grant date	Mar 18, 2025

Abstract

A method for determining a state of health of at least one electrochemical energy store includes bringing the electrochemical energy store to a predefined voltage state, after which the electrochemical energy store is discharged for a predefined time period and using predefined electric currents, and determining a rate of voltage change during the discharge, on the basis of which the state of health is determined.

First claim

What is claimed is:

1. A method for determining a state of health of at least one electrochemical energy store, the method comprising the following steps:
a) measuring a value of a voltage of the electrochemical energy store;
b) comparing the measured value to a predefined setpoint value for the voltage;
c) changing a charge state of the electrochemical energy store by, depending on a result of the comparison of step b), either charging or discharging the electrochemical energy store, to thereby bring the electrochemical energy store into a predefined state in which the electrochemical energy store has the predefined setpoint value for the voltage;
d) based on, and subsequent to, the predefined state being reached, discharging the electrochemical energy store for a predefined time period using predefined electric currents;
e) measuring values of the voltage of the electrochemical energy store during the discharging of step d);
f) determining, based on the values of the voltage obtained by the measuring of step e), a rate at which the voltage of the electrochemical energy store changed over the predefined time period;
g) comparing a value of the determined rate with predefined setpoint rates; and
h) determining the state of health of the electrochemical energy store based on a result of the comparison in step g).

2. The method for determining a state of health of an electrochemical energy store as recited in claim 1 , further comprising the following steps:
a.1) acquiring a temperature variable which represents a temperature of the electrochemical energy store;
a.2) comparing the acquired temperature variable with a predefined setpoint temperature variable; and
a.3) generating signals for heating and/or cooling the electrochemical energy store based on the result of the comparison in step a.2).

3. The method for determining a state of health of an electrochemical energy store as recited in claim 1 , further comprising the following step:
c.1) waiting for a predefined time for a relaxation of the electrochemical energy store from when the predefined state is reached in step c) until performance of step d).

4. The method for determining a state of health of an electrochemical energy store as recited in claim 1 , further comprising the following steps:
e.1) discharging the electrochemical energy store for a further predefined time period using predefined currents;
e.2) repeating the steps d) and e) at least once;
e.3) determining a mean value of the rates, wherein mean value is used as the value in the comparison of step g).

5. The method for determining a state of health of an electrochemical energy store as recited in claim 1 , further comprising the following step:
i) validating the state of health by evaluating the voltage during the discharging of step d) and/or during a relaxation of the electrochemical energy store for a predefined amount of time from when the predefined state is reached in step c) until performance of step d) and/or by evaluating a voltage characteristic following a current jump.

6. The method for determining a state of health of an electrochemical energy store as recited in claim 1 , further comprising the following steps:
i) acquiring a further value of the voltage of the electrochemical energy store;
j) comparing the acquired further value of the voltage with the value of the voltage measured in step a);
k) generating signals for either charging and/or discharging the electrochemical energy store depending on the result of the comparison in step j).

7. The method for determining a state of health of an electrochemical energy store as recited in claim 1 , wherein the predefined electric currents are limited to a predefined rage of 0.1 C to 0.5 C.

8. A diagnostic device, comprising:
an electronic control device configured to determine a state of health of at least one electrochemical energy store, the electronic control device configured to:
a) measure a value of a voltage of the electrochemical energy store;
b) compare the measured value to a predefined setpoint value for the voltage;
c) change a charge state of the electrochemical energy store by, depending on a result of the comparison of step b), either charging or discharging the electrochemical energy store, to thereby bring the electrochemical energy store into a predefined state in which the electrochemical energy store has the predefined setpoint value for the voltage;
d) based on and subsequent to the predefined state being reached, discharge the electrochemical energy store for a predefined time period using predefined electric currents;
e) measure values of the voltage of the electrochemical energy store during the discharging of step d);
f) determine, based on the values of the voltage obtained by the measuring of step e), a rate at which the voltage of the electrochemical energy store changed over the predefined time period;
g) compare the determined rate with predefined setpoint rates; and
h) determine the state of health of the electrochemical energy store based on a result of the comparison in step g).

9. The diagnostic device as recited in claim 8 , wherein the diagnostic device is configured to diagnose an electric vehicle, or a hybrid vehicle, or a plug-in hybrid vehicle, or an airplane, or a pedelec or an electric bike, or an electric handheld tool, or a stationary accumulators for storing regeneratively obtained electrical energy.

10. A non-transitory machine-readable memory medium on which is stored a computer program for determining a state of health of at least one electrochemical energy store, the computer program, when executed by a computer, causing the computer to perform the following steps:
a) measuring a value of a voltage of the electrochemical energy store;
b) comparing the measured value to a predefined setpoint value for the voltage;
c) changing a charge state of the electrochemical energy store by, depending on a result of the comparison of step b), either charging or discharging the electrochemical energy store, to thereby bring the electrochemical energy store into a predefined state in which the electrochemical energy store has the predefined setpoint value for the voltage;
d) based on and subsequent to the predefined state being reached, discharging the electrochemical energy store for a predefined time period using predefined electric currents;
e) measuring values of the voltage of the electrochemical energy store during the discharging of step d);
f) determining, based on the values of the voltage obtained by the measuring of step e), a rate at which the voltage of the electrochemical energy store changed over the predefined time period;
g) comparing the determined rate with predefined setpoint rates; and
h) determining the state of health of the electrochemical energy store based on a result of the comparison in step g).

Assignees

• Bosch Gmbh Robert

Inventors

• Simonis Christian
• Woll Christoph

Classifications

• G01R31/388

  involving voltage measurements · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title

• G01R31/392 Primary

  Determining battery ageing or deterioration, e.g. state of health · CPC title