Battery Condition Monitor

• US 20080183408A1
• Filed: 03/03/2006
• Published: 07/31/2008
• Est. Priority Date: 03/04/2005
• Status: Active Grant

• Current Assignee: Autonetworks Technologies, Ltd. (Sumitomo Corporation), Sumitomo Electric Industries Limited (Sumitomo Corporation), Sumitomo Wiring Systems Limited (Sumitomo Corporation)
• Original Assignee: Autonetworks Technologies, Ltd. (Sumitomo Corporation)
• Inventors: Anzai, Yoichiro, Mayama, Shuji, Matsuura, Takahiro
• Granted Patent: US 7,676,334 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements

Abstract

An object of the present invention is to provide a battery condition monitor that is capable of reducing labor and equipment costs for parameter setting for evaluation of the battery'"'"'s condition and capable of readily responding to variations due to individual differences among the same model of vehicles. The battery condition monitor according to the present invention measures a lower limit voltage value for the time when a load during engine startup is substantially connected to a brand-new battery, as an initial reference lower limit voltage value V_LIF; and derives a reference discharge characteristic of the brand-new battery with respect to the vehicle-unique load during engine startup, using the initial reference lower limit voltage value V_LIF, an initial reference no-load voltage value V_OIF which is a no-load voltage of that battery, and information about the rate of change in the internal resistance with respect to change in the no-load voltage of the battery, the information being previously stored in a storage unit, thereby to evaluate the condition of the battery based on the reference discharge characteristic.

Claims

1-8. -8. (canceled)

9. A battery condition monitor for storing an initial condition defined by a combination of a battery mounted on a vehicle and said vehicle and comparing the initial condition and a condition during use, using a voltage of said battery which is ever changing before startup and an approximate minimum voltage thereof which is ever changing during startup, thereby to monitor the remaining capacity and the state of deterioration of said battery,

said battery condition monitor comprising:

detection means for detecting an output voltage of said battery;

first storage means for storing first information indicating the relationship between change in a no-load voltage value and change in an internal resistance value for said battery being in a nearly brand-new condition;

processing means for, based on said first information stored in said first storage means, based on an initial reference no-load voltage value which is a no-load voltage value detected by said detection means for said battery being in a nearly brand-new and nearly fully-charged condition, and based on an initial reference on-load voltage value which is an output voltage value detected by said detection means when said battery being in a nearly brand-new and nearly fully-charged condition is connected to a predetermined load to be discharged, deriving a reference discharge characteristic of said battery that indicates the relationship between change in said no-load voltage value and change in an on-load voltage value which is an output voltage value detected upon discharge of said predetermined load; and

second storage means for storing second information including said initial reference no-load voltage value and said initial reference on-load voltage value,

wherein the derivation of said reference discharge characteristic becomes possible without setting a unique parameter for said battery and for each vehicle.

10. The battery condition monitor according to claim 9, wherein if the no-load voltage of said battery is defined as V_OI, the on-load voltage of said battery as V_LI, said initial reference no-load voltage value as V_OIF, said initial reference on-load voltage value as V_LIF, an internal resistance of said battery as R_BI, and the internal resistance value of said battery being in a nearly brand-new and nearly fully-charged condition as R_BIF, said first information is given as a function f(V_OI)=R_BI/R_BIF, and said reference discharge characteristic is expressed as:

V_L1=[V_LK/{(V_OI−

V_LK)·

f(V_OI)+V_LK}]·

V_OI

where V_LK=(V_LIF/V_OIF)·

V_OI

11. The battery condition monitor according to claim 9, wherein

said processing means derives the degree of deterioration of said battery and the remaining amount of charge therein based on said reference discharge characteristic, based on an used no-load voltage value which is a no-load voltage value detected by said detection means for said battery which has started to be used, and based on an used on-load voltage value which is an output voltage value detected by said detection means for the time when said battery which has started to be used is connected to said predetermined load to be discharged.

12. The battery condition monitor according to claim 11, wherein

said processing means determines said degree of deterioration based on a difference between said initial reference no-load voltage value and a corresponding no-load voltage value which is a no-load voltage value corresponding to said used on-load voltage value in said reference discharge characteristic, and based on a difference between said initial reference no-load voltage value and said used on-load voltage value.

13. The battery condition monitor according to claim 11, wherein said processing means determines:

a first ratio of a difference between said initial reference no-load voltage value and said used on-load voltage value to a difference between said initial reference no-load voltage value and a corresponding no-load voltage value which is a no-load voltage value corresponding to said used on-load voltage value in said reference discharge characteristic, and

a minimum used no-load voltage value which is a no-load voltage value for the time when the remaining amount of charge in said battery which has started to be used is approximately zero, so that said first ratio becomes equal to a second ratio of a difference between said initial reference no-load voltage value and said minimum used no-load voltage value to a difference between said initial reference no-load voltage value and a minimum reference no-load voltage value which is a no-load voltage value for the time when the remaining amount of charge in said battery being in a nearly brand-new condition is approximately zero,

wherein said remaining amount of charge is determined based on the difference between said initial reference no-load voltage value and said minimum used no-load voltage value and based on a difference between said used no-load voltage value and said minimum used no-load voltage value.

14. The battery condition monitor according to claim 10, wherein

said processing means derives the degree of deterioration of said battery and the remaining amount of charge therein based on said reference discharge characteristic, based on an used no-load voltage value which is a no-load voltage value detected by said detection means for said battery which has started to be used, and based on an used on-load voltage value which is an output voltage value detected by said detection means for the time when said battery which has started to be used is connected to said predetermined load to be discharged.

15. The battery condition monitor according to claim 14, wherein

said processing means determines said degree of deterioration based on a difference between said initial reference no-load voltage value and a corresponding no-load voltage value which is a no-load voltage value corresponding to said used on-load voltage value in said reference discharge characteristic, and based on a difference between said initial reference no-load voltage value and said used on-load voltage value.

16. The battery condition monitor according to claim 14, wherein

said processing means determines:

a first ratio of a difference between said initial reference no-load voltage value and said used on-load voltage value to a difference between said initial reference no-load voltage value and a corresponding no-load voltage value which is a no-load voltage value corresponding to said used on-load voltage value in said reference discharge characteristic, and

a minimum used no-load voltage value which is a no-load voltage value for the time when the remaining amount of charge in said battery which has started to be used is approximately zero, so that said first ratio becomes equal to a second ratio of a difference between said initial reference no-load voltage value and said minimum used no-load voltage value to a difference between said initial reference no-load voltage value and a minimum reference no-load voltage value which is a no-load voltage value for the time when the remaining amount of charge in said battery being in a nearly brand-new condition is approximately zero,

wherein said remaining amount of charge is determined based on the difference between said initial reference no-load voltage value and said minimum used no-load voltage value and based on a difference between said used no-load voltage value and said minimum used no-load voltage value.