Battery management system and driving method thereof

• US 8,669,741 B2
• Filed: 06/22/2007
• Issued: 03/11/2014
• Est. Priority Date: 08/11/2006
• Status: Expired due to Fees

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Seo, Se-Wook, Lee, Young-Jo, Tae, Yong-Jun, Yun, Han-Seok, Lim, Gye-Jong, Kim, Beom-Gyu, Park, Ho-Young, Choi, Soo-Seok
• Primary Examiner(s): Tso, Edward
• Assistant Examiner(s): BOATENG, ALEXIS ASIEDUA
• Application Number:
  US11/767,094
• Publication Number:
  US 20080036421A1
• Time in Patent Office: 2,454 Days
• Field of Search: 320/132, 320/104, 320/134, 320/135, 320/136, 320/133, 320/137
• US Class Current: 320/132
• CPC Class Codes: B60K 2001/005 the electric storage means
• CPC Class Codes: B60K 6/28 characterised by the electric energy storing means, e.g. batteries or capacitors
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/24 for controlling the temperature of batteries
• CPC Class Codes: B60L 58/26 by cooling
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 2510/24 Energy storage means
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2510/246 Temperature
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A battery management system (BMS) manages a battery for a hybrid vehicle including an engine control unit and a motor generator controlled by the engine control unit and connected to a battery including at least one battery pack, each pack including a plurality of battery cells. The BMS includes a sensor and an MCU unit. The sensor detects temperature, current, and open circuit voltage (OCV) of the battery. The MCU receives the detected temperature, current, and OCV, calculates a key-off time period which is a period between a time point when a battery key-on state ends and a time point when a subsequent battery key-on state begins, calculates an OCV error range corresponding to an SOC error range detected at the key-off time point, and infers an initial SOC of the battery.

Claims

1. A battery management system (BMS) for a hybrid vehicle that includes an engine control unit, a motor generator controlled by the engine control unit, and a battery in which a plurality of battery cells are grouped into a plurality of battery packs, comprising:

a sensor that senses temperature, current, and open circuit voltage (OCV) of the battery at a present key-on time point; and

a main control unit (MCU) that calculates a key-off time period, the key-off time period being an amount of time that the battery has been in a key-off state from a key-off time point to a time point at which the present key-on state begins, that calculates a difference between temperatures of the battery respectively detected at the key-on time point and the key-off time point by receiving data of the temperature of the battery, that detects an OCV error range corresponding to an SOC error range at tile key-off time point, and that infers an initial SOC of the battery by using the OCV and the OCV error range;

wherein the MCU takes the SOC detected at the key-off time point as the initial SOC when the key-off time period is shorter than a reference time period.

2. The BMS of claim 1, wherein, if the key-off time period is longer than the reference time period,

the MCU receives the temperatures and the OCVs of the battery respectively detected at the key-on time point and the key-off time point, detects the OCV error range corresponding to the SOC error range at the key-off time point, and infers the initial SOC using a table that relates SOCs to OCVs based on temperature if the OCV detected at the key-on time point is a voltage that is not within the OCV error range corresponding to the SOC error range detected at the key-off time point.

3. The BMS of claim 2, wherein the MCU takes the SOC detected at the key-off time point as the initial SOC of the battery when the OCV detected at the key-on time point is a voltage within the OCV error range corresponding to the SOC error range detected at the key-off time point and when a difference between temperatures of the battery at the key-on time point and the key-off time point is less than a reference temperature value.

4. The BMS of claim 3, wherein the MCU assumes the initial SOC using a table that relates SOCs to OCVs based on temperature when the OCV at the key-on time point is a voltage within the OCV error range corresponding to the SOC error range detected at the key-off time point and when the difference between temperatures detected at the key-on time point and key-off time point is greater than the reference temperature value.

5. The BMS according to claim 1, wherein the reference time period is a predetermined time period representing an amount of time that elapses after the key-on time point while the OCV becomes stabilized.

6. The BMS of claim 3, wherein the reference temperature value is a predetermined temperature value that is determined based on a temperature history of temperature differences of the battery detected at the key-on time point and the key-off time point.

7. A hybrid vehicle comprising

an engine control unit;

a motor generator controlled by the engine control unit, and

a battery connected to the motor generator and comprising a plurality of battery cells grouped into a plurality of battery packs; and

the battery management system of claim 1.