Device and Method for Measuring the Capacity Degradation of a Battery

• US 20140052396A1
• Filed: 04/28/2011
• Published: 02/20/2014
• Est. Priority Date: 04/28/2011
• Status: Abandoned Application

• Current Assignee: SK Innovation Company Limited
• Original Assignee: SK Innovation Company Limited
• Inventors: Lim, Jae Hwan, Jin, Shan Shan, Han, Chong Hun, Cho, Sung Woo, Chung, Hyun Seok
• Application Number:
  US14/114,040
• Publication Number:
  US 20140052396A1
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/16 responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

Provided are an apparatus and a method for measuring battery capacity fade. The apparatus for measuring battery capacity fade includes: at least one battery used in a hybrid vehicle, a plug-in hybrid electric vehicle or an electric vehicle; a sensing unit sensing current, voltage and temperature of the at least one battery; a data processing unit measuring voltage and current data from the sensing unit if the current is constant current in a charging period and state of charge (SOC) is in a predetermined region; and a calculating unit setting at least two points on the voltage data and applying the voltage data corresponding to the at least two points to an equivalent circuit model of the at least one batter, to calculate faded capacity.

Claims

1. An apparatus for measuring battery capacity fade, comprising:

at least one battery used in a hybrid vehicle, a plug-in hybrid electric vehicle or an electric vehicle;

a sensing unit sensing current, voltage and temperature of the at least one battery;

a data processing unit measuring voltage and current data from the sensing unit if the current is constant current in a charging period and a state of charge (SOC) is in a predetermined region; and

a calculating unit setting at least two points on the voltage data and applying the voltage data corresponding to the at least two points to an equivalent circuit model of the at least one battery, to calculate faded capacity.

2. The apparatus of claim 1, wherein the calculating unit sums up the faded capacities stored in a predetermined period in which the vehicle travels to calculate a moving average faded capacity.

3. The apparatus of claim 2, further comprising a memory unit storing the voltage, the current, the faded capacities, and the moving average faded capacity.

4. The apparatus of claim 2, wherein the faded capacities are calculated using

5. The apparatus of claim 4, wherein a₁ has different values depending on characteristics and a temperature of a battery and does not vary even if the capacity fades, and wherein the equivalent circuit model is an electrical circuit representing the battery with parameters such as a total resistance R*, a current I, a terminal voltage V and an electromotive force Vo.

11. The apparatus of claim 1, further comprising a memory unit storing the voltage, the current, the faded capacities, and the moving average faded capacity.

12. The apparatus of claim 1, wherein the faded capacities are calculated using

6. A method for measuring battery capacity fade, comprising:

determining whether a current flowing through at least one battery used in a plug-in hybrid electric vehicle or an electric vehicle is a constant current in a charging period or not;

determining whether a state of charging (SOC) is in a predetermined region or not if the current is a constant current in the charging period;

measuring current, voltage and temperature data of the at least one battery if the SOC is in the predetermined region;

setting at least two points on the measured voltage data; and

applying the voltage data corresponding to the at least two points to an equivalent circuit model of the at least one battery to calculate a fade capacity.

7. The method of claim 6, further comprising summing up the faded capacities stored in a predetermined period in which the vehicle travels to calculate a moving average faded capacity.

8. The method of claim 7, wherein the faded capacities are calculated using

9. The method of claim 8, wherein a₁ has different values depending on characteristics and a temperature of a battery and does not vary even if the capacity fades when an SOC of the battery is in the predetermined region, and wherein the equivalent circuit model is an electrical circuit representing the battery with parameters such as a total resistance R*, a current I, a terminal voltage V and an electromotive force Vo.

10. The method of claim 8, further comprising calculating a state of health (SOH) of a battery, wherein the SOH is calculated using

13. The method of claim 6, wherein the faded capacities are calculated using