Battery charging and discharging control apparatus for hybrid powered vehicle

• US 6,133,707 A
• Filed: 05/20/1999
• Issued: 10/17/2000
• Est. Priority Date: 06/25/1998
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kikuchi, Yoshiaki, Tojima, Kazuo, Nakayama, Yoshiyuki, Sekimori, Toshiyuki
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US09/315,149
• Time in Patent Office: 516 Days
• Field of Search: 320/116, 320/118, 320/120, 320/122, 320/127, 320/135, 320/136, 320/FOR 112, 320/FOR 117
• US Class Current: 320/104
• CPC Class Codes: B60K 6/28 characterised by the electric energy storing means, e.g. batteries or capacitors
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• 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 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/1415 with a generator driven by a prime mover other than the motor of a vehicle
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y10S 903/903 having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/907 Electricity storage, e.g. battery, capacitor

Abstract

A voltage detector (12) detects the voltage levels of the battery blocks of the battery set (10). A presence of an overdischarged cell is detected when a voltage difference between each of the battery blocks reaches or exceeds a predetermined value (for example, 1V). At this point, a battery ECU (14) sets the SOC value of the battery set (10) at the lower control limit value (for example, 20%). This triggers an HV ECU (16) to control the load (18) such that charging is effectuated in the battery set (10). If further discharge occurs, the battery set (10) is disconnected from the load (18) by a relay (20).

Claims

1. A battery control apparatus for a hybrid powered vehicle mounted with an engine and a motor, comprising:

a battery set for supplying electricity to said motor, having a plurality of battery blocks connected in series, each of said battery blocks containing a predetermined number of battery cells;

a generator which is driven by said engine and supplies electricity to said battery set;

an SOC detection device for detecting SOC of the battery set;

a control device for controlling, in accordance with an SOC detected in said SOC detection device, the supply of electricity to the motor from said battery set and the generation of electricity in the generator; and

an overdischarge detection device for detecting an overdischarge in at least one of the battery cells;

wherein

said control device controls the supply of electricity to the motor and the generation of electricity in the generator when an overdischarged cell is detected by said overdischarge detection device such that charging of said battery set is effectuated.

2. The apparatus according to claim 1, wherein

said overdischarge detection means determines respective voltage levels in each of the battery blocks, and determines that at least one battery cell is overdischarged when it detects that a difference between each of the determined voltage levels of the battery blocks has reached or exceeded a predetermined value.

3. The apparatus according to claim 1, wherein

said SOC detection device supplies a predetermined low SOC value to the control device when an overdischarge is detected in said overdischarge detection device, while the control device controls, in accordance with the supplied predetermined low SOC value, the supply of electricity to the motor and the generation of electricity in the generator such that charging of the battery set is effectuated.

4. The apparatus according to claim 3, wherein

said predetermined low SOC value is the lowest allowable value for the SOC of the battery set.

5. The apparatus according to claim 1, wherein

any output from the battery set is prohibited when the detected SOC further lowers after the voltage difference between each of the battery blocks detected by said voltage detection device reaches or exceeds a predetermined value.

6. The apparatus according to claim 5, wherein

the prohibition of output from said battery set is executed by disconnecting an electrical connection between the battery set and the motor.