US 5,631,533 AGranted

Charging and discharging control device for secondary battery

AssigneeNissan Motor Co., Ltd.

InventorTakashi Imaseki

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Abstract

A charging and discharging control device for a secondary battery includes a secondary battery, a controller, a charging unit for charging the battery, a ON/OFF switch between the battery and the charging unit and a control switch for controlling the discharge current. At charging the battery, the ON/OFF switch is turned on and a voltage Ve of the secondary battery is compared with a charge stop voltage Vmax by the controller. If Ve.gtoreq.Vmax, the charging operation is ended. At discharging, the control is turned on and the voltage Ve is compared with a discharge stop voltage Vmin. If Ve.ltoreq.Vmin, the discharging operation is ended. Corresponding to charging/discharging history of the battery, the controller corrects the voltage Vmin so as to be increased and the voltage Vmax so as to be decreased, whereby the life span of the secondary battery can be extended.

Claims5

Dependent claims

A charging and discharging control device for a secondary battery, said control device comprising:

discharging control means for stopping discharging of said secondary battery when a voltage thereof becomes less than a predetermined discharge stop voltage during discharging of said secondary battery;
charging control means for stopping charging of said secondary battery when the voltage thereof is in excess of a predetermined charge stop voltage during charging of said secondary battery;
and
history estimating means for estimating the charging/discharging history of said secondary battery on the basis of condition thereof;
wherein said discharging control means corrects said predetermined discharge stop voltage so as to be increased corresponding to the charging/discharging history estimated by said history estimating means;
wherein said charging control means corrects said predetermined charge stop voltage so as to be decreased corresponding to the charging/discharging history estimated by said history estimating means,
wherein said secondary battery consists of a plurality of secondary batteries connected with each other;
wherein said charging control means includes current changing means which, in case that a charging voltage in a specified secondary battery reaches said predetermined charge stop voltage, directs a flow of charging current to the other secondary batteries by a by-pass operation of the flow of charging current;
and
wherein said history estimating means estimates the charging/discharging history of said secondary battery on the basis of a number of said by-pass operations.

7 more elements

A charging and discharging control device for a secondary battery, said control device comprising:

discharging control means for stopping discharging of said secondary battery when a voltage thereof becomes less than a predetermined discharge stop voltage during discharging of said secondary battery;
charging control means for stopping charging of said secondary battery when the voltage thereof is in excess of a predetermined charge stop voltage during charging of said secondary battery;
and
history estimating means for estimating the charging/discharging history of said secondary battery on the basis of condition thereof;
wherein said discharging control means corrects said predetermined discharge stop voltage so as to be increased corresponding to the charging/discharging history estimated by said history estimating means;
wherein said charging control means corrects said predetermined charge stop voltage so as to be decreased corresponding to the charging/discharging history estimated by said history estimating means, and
wherein said secondary battery is used for driving a vehicle and wherein said history estimating means estimates the charging/discharging history of said secondary battery on the basis of a period of using thereof, a number of cycles between charging and discharging and a traveling range of the vehicle.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/405,054Filed 15 Mar 1995
Priority: JP 6-07003915 Mar 1994
Granted: 20 May 1997
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H02J 7/54
For charge balancing, e.g. equalisation of charge between batteries: passive balancing, e.g. using resistors or parallel MOSFETs
H02J 7/933
Regulation of charging or discharging current or voltage: the cycle being controlled or terminated in response to electric parameters
G01R 31/3835
Arrangements for monitoring battery or accumulator variables, e.g. SoC: involving only voltage measurements
H02J
Power supply and charging