Battery management system and driving method thereof

• US 7,652,449 B2
• Filed: 09/20/2007
• Issued: 01/26/2010
• Est. Priority Date: 09/26/2006
• Status: Expired due to Fees

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Park, Ho-Young, Choi, Soo-Seok, Lee, Young-Jo, Kim, Beom-Gyu, Seo, Se-Wook, Lim, Gye-Jong, Yun, Han-Seok, Tae, Yong-Jun
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): PACHECO, ALEXIS BOATENG
• Application Number:
  US11/902,337
• Publication Number:
  US 20080224709A1
• Time in Patent Office: 859 Days
• Field of Search: 320/134, 320/104, 320/137, 320/127, 307/10.7, 307/149, 307/150, 702/63, 324/426, 324/433
• US Class Current: 320/104
• 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 58/15 Preventing overcharging
• 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: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

In a battery management system and a driving method thereof, the system includes a sensor and a micro control unit (MCU). The sensor senses a voltage and a current of a battery, and generates an estimation current of the battery using a result of cumulatively calculating the battery current by a unit of a predetermined period. The MCU receives the battery voltage and the estimation current, sets a voltage of the battery in a key-on state as a first voltage, sets a voltage of the battery after a first period as a second voltage, and calculates an internal resistance of the battery using a difference between the first and second voltages and an average value of the estimation current.

Claims

1. A battery management system, comprising:

a sensor for sensing a voltage and a current of a battery, and for generating an estimation current of the battery using a result of cumulatively calculating the battery current by a unit of a predetermined period; and

a micro control unit (MCU) for receiving the voltage of the battery and the estimation current of the battery, for setting a voltage of the battery in a key-on state as a first voltage, for setting a voltage of the battery after a first period, which is set according to a condition of controlling a vehicle, as a second voltage, and for calculating an internal resistance of the battery using a difference between the first and second voltages and an average value of the estimation current.

2. The system of claim 1, wherein the estimation current is generated by cumulatively calculating the current of the battery for a unit of a second period, and by dividing the calculated current of the battery by a time corresponding to the second period.

3. The system of claim 2, wherein the MCU samples the estimation current of the first period, and calculates the average value of the estimation current.

4. The system of claim 3, wherein the MCU calculates the internal resistance of the battery using the following equation:

$\mathrm{Rb}=\frac{V_2-V_1}{I_{\mathrm{ave}}}\times <br><br>1000<br><br>\left[m<br><br><br><br>\mathrm{\Omega <br><br>}\right]$

where

V₁ is the battery voltage of the battery in the key-on state,

V₂ is the voltage of the battery after the first period, and

I_ave is the average value of the estimation current of the battery.

5. The system of claim 4, wherein the sensor comprises an electric current estimator for comparing the current of the battery to a reference current to produce a comparison result, for cumulatively calculating a deviation based on the comparison result, for dividing the calculated deviation by the time corresponding to the second period, and for generating the estimation current.

6. A method for driving a battery management system managing a battery, said method comprising the steps of:

setting a voltage of the battery in a key-on state as a first voltage;

setting a voltage of the battery after a first period as a second voltage;

calculating an average value of an estimation current of the battery for the first period; and

calculating an internal resistance of the battery using a difference between the first and second voltages and the average value of the estimation current.

7. The method of claim 6, wherein the step of calculating the average value of the estimation current of the battery comprises cumulatively calculating a current of the battery for a unit of a second period to produce a calculated result, dividing the calculated result by a time corresponding to the second period, and generating the estimation current of the battery.

8. The method of claim 7, wherein the step of calculating the average value of the estimation current of the battery is performed by sampling the estimation current of the battery for the first period.

9. The method of claim 8, wherein the step of calculating the internal resistance of the battery is performed using the following equation:

$\mathrm{Rb}=\frac{V_2-V_1}{I_{\mathrm{ave}}}\times <br><br>1000<br><br>\left[m<br><br><br><br>\mathrm{\Omega <br><br>}\right]$

where

V₁ is the voltage of the battery in the key-on state,

V₂ is the voltage of the battery after the first period, and

I_ave is the average value of the estimation current of the battery.

10. The method of claim 6, wherein the step of calculating the average value of the estimation current of the battery is performed by sampling the estimation current of the battery for the first period.

11. The method of claim 10, wherein the step of calculating the internal resistance of the battery is performed using the following equation:

$\mathrm{Rb}=\frac{V_2-V_1}{I_{\mathrm{ave}}}\times <br><br>1000<br><br>\left[m<br><br><br><br>\mathrm{\Omega <br><br>}\right]$

where

V₁ is the voltage of the battery in the key-on state,

V₂ is the voltage of the battery after the first period, and

I_ave is the average value of the estimation current of the battery.

12. The method of claim 6, wherein the step of calculating the internal resistance of the battery is performed using the following equation:

$\mathrm{Rb}=\frac{V_2-V_1}{I_{\mathrm{ave}}}\times <br><br>1000<br><br>\left[m<br><br><br><br>\mathrm{\Omega <br><br>}\right]$

where

V₁ is the voltage of the battery in the key-on state,

V₂ is the voltage of the battery after the first period, and

I_ave is the average value of the estimation current of the battery.