DETECTING METHOD FOR DETECTING INTERNAL INFORMATION OF A RECHARGEABLE BATTERY, DETECTING APPARATUS FOR DETECTING INTERNAL INFORMATION OF A RECHARGEABLE BATTERY, APPARATUS IN WHICH SAID DETECTING METHOD IS APPLIED, APPARATUS INCLUDING SAID DETECTING APPARATUS, AND STORAGE MEDIUM IN WHICH A SOFTWARE PROGRAM OF SAID DETECTING METHOD IS STORED

• US 6,683,440 B2
• Filed: 05/29/2002
• Issued: 01/27/2004
• Est. Priority Date: 05/29/2001
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kawakami, Soichiro, Degura, Yasusaburo
• Primary Examiner(s): Tso, Edward H
• Application Number:
  US10/156,008
• Publication Number:
  US 20030006735A1
• Time in Patent Office: 608 Days
• Field of Search: 320/132, 320/133, 320/134, 320/136, 320/149, 320/155, 320/157, 320/160, 320/162, 320/164, 320/125
• US Class Current: 320/133
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/3828 using current integration
• 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: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: H02J 7/0071 with a programmable schedule

Abstract

A detecting method for detecting internal information of an inspective rechargeable battery when said inspective rechargeable battery is charged by a constant current-constant voltage charging regime, comprising at least a step (A) of measuring an elapse of time (t) from the time when a constant current charging mode at a constant current value I₀ is shifted to a constant voltage charging mode at a constant voltage V_max and measuring a charge current value I in the constant voltage charging mode, a step (B) of obtaining a period of time from said shift time to the constant voltage charging in the constant voltage charging mode until the time when said charge current value I₀ in the constant voltage charging mode reaches a given current value I_M, and a step (C) of obtaining an electricity quantity charged in the constant voltage charging mode with respect to the inspective rechargeable battery.

Claims

1. A detecting method for detecting internal information of an inspective rechargeable battery when said inspective rechargeable battery is charged by a constant current-constant voltage charging regime in that charging is commenced at a constant current value I₀ and after the battery voltage of said rechargeable battery reaches a given voltage value V_max, the charging is performed at a constant voltage V_max until the termination thereof, said detecting method comprising at least:

a step (A) of measuring an elapse of time (t) from the time when a constant current charging mode at a constant current value I₀ is shifted to a constant voltage charging mode at a constant voltage V_max and measuring a charge current value I in the constant voltage charging mode;

a step (B) of obtaining a period of time from said shift time to the constant voltage charging in the constant voltage charging mode until the time when said charge current value I in the constant voltage charging mode reaches a given current value I_M; and

a step (C) of obtaining an electricity quantity charged in the constant voltage charging mode with respect to the inspective rechargeable battery.

2. The detecting method according to claim 1 which further includes a step (D) of referring to charge current characteristics of a corresponding normal rechargeable battery as a reference standard for the inspective rechargeable battery in the constant voltage charging mode when said normal rechargeable battery is charged by the constant current-constant voltage charging regime, said charge current characteristics including relationships I_N(t) of a charge current value I_N to a constant voltage charging time t.

3. The detecting method according to claim 1 or 2, wherein the internal information detected includes the presence or absence of short circuit, electricity storable capacity, internal resistance, charged electricity quantity, remaining capacity (=presently stored electricity quantity=dischargeable capacity) respectively of the inspective rechargeable battery, presently residual electricity quantity with which the inspective rechargeable battery is still capable of being used, and a combination of these items.

4. The detecting method according to claim 1, wherein when the charge current value takes a positive value when the charge time in the constant voltage charging mode becomes infinite, the inspective rechargeable battery is judged to be short-circuited.

5. The detecting method according to claim 1, wherein when the charge current value converges to substantially zero when the charge time in the constant voltage charging mode becomes infinite, the inspective rechargeable battery is judged to be not short-circuited.

6. The detecting method according to claim 4, wherein from a change in the charge current value in the constant voltage charging mode, a converged value of the charge current value when the charge time is infinitely elapsed is computed.

7. The detecting method according to claim 2, wherein the relationships I_N(t) include previously measured data of the normal rechargeable battery, function formulas obtained from said measured data, and function formulas based on said measured data which are obtained by way of simulation by a computer.

8. The detecting method according to claim 1 or 2, wherein the charging is terminated when the charge current value in the constant voltage charging mode becomes less than a given current value I_min or when a given period of time t_f elapses from the commencement of the charging.

9. The detecting method according to claim 1 or 2 which further includes a step (E) of judging whether or not the inspective rechargeable battery is short-circuited.

10. The detecting method according to claim 1, wherein the electricity quantity charged in the constant voltage charging mode is an electricity quantity charged until the time when the charging is terminated or an electricity quantity charged until the time when the current value becomes substantially zero.

11. The detecting method according to claim 10, wherein the electricity quantity charged until the time when the current value becomes substantially zero is a value extrapolated from a change in the charge current value in the constant voltage charging mode or a value computed from said change.

12. The detecting method according to claim 2, wherein the inspective rechargeable battery is an inspective rechargeable battery which is not short-circuited;

and when with respect to the inspective rechargeable battery, the period of time from the time when the charging at the constant current value I₀ is shifted to the charging at the constant voltage V_max until the current value becomes the given current value I_M is t_M′

, and with respect to the normal rechargeable battery, the period of time from the time when the charging at the constant current value I₀ is shifted to the charging at the constant voltage V_max until the current value becomes the given current value I_M is t_M;

the inspective rechargeable battery is judged as follows;

(i) when (t_M′

−

t_M)>

a>

0 (with a being a constant decided by the kind of the rechargeable battery), the inspective rechargeable battery has a greater internal resistance than that of the normal rechargeable battery, and

(ii) when (t_M−

t_M′

)>

b>

0 (with b being a constant decided by the kind of the rechargeable battery), the inspective rechargeable battery has a smaller electricity storable capacity than that of the normal rechargeable battery.

13. The detecting method according to claim 2, wherein the inspective rechargeable battery is an inspective rechargeable battery which is not short-circuited;

and when the electricity quantity charged at the constant voltage V_max in the constant voltage charging mode with respect to the inspective rechargeable battery is Q_cv′ and

the electricity quantity charged at the constant voltage V_max in the constant voltage charging mode with respect to the normal rechargeable battery is Q_cv;

the inspective rechargeable battery is judged as follows;

(iii) when (Q_cv′

−

Q_cv)>

c>

0 (with c being a constant decided by the kind of the rechargeable battery), the inspective rechargeable battery has a greater internal resistance than that of the normal rechargeable battery, and

(iv) when (Q_cv×

Q_cv′

)>

d>

0 (with d being a constant decided by the kind of the rechargeable battery), the inspective rechargeable battery has a smaller electricity storable capacity than that of the normal rechargeable battery.

14. The detecting method according to claim 2, wherein the inspective rechargeable battery is an inspective rechargeable battery which is not short-circuited and whose electricity storable capacity is presumably decreased by D time (with D being a constant of 0<

D≦

1) that of the normal rechargeable battery; and

when with respect to the inspective rechargeable battery, the period of time from the time when the charging at the constant current value I₀ is shifted to the charging at the constant voltage V_max until the current value becomes the given current value I_M is t_M′ and

the electricity quantity charged at the constant voltage V_max in the constant voltage charging mode is Q_cv′

, and with respect to the normal rechargeable battery, the period of time from the time when the charging at the constant current value I₀ is shifted to the charging at the constant voltage V_max until the current value becomes the given current value I_M is t_M and the electricity quantity charged at the constant voltage V_max in the constant voltage charging mode is Q_cv;

the inspective rechargeable battery is judged to have an electricity storable capacity which is D time that of the normal rechargeable battery from the following equation (1);

15. The detecting method according to claim 14, wherein the electricity storable capacity of the inspective rechargeable battery is computed to be C′

=C×

D from the electricity storable capacity C of the normal rechargeable battery.

16. The detecting method according to claim 9, wherein the inspective rechargeable battery is judged to be not short-circuited or short-circuited by detecting an internal state thereof when said rechargeable battery is charged, discharged or paused without performing the charging or the discharging.

17. The detecting method according to claim 16, wherein the inspective rechargeable battery is judged to be not short-circuited or short-circuited by referring to at least one kind of a factor selected from the group consisting of an increase rate in the battery voltage upon the constant current charging mode, a decrease rate in the charge current upon the constant voltage charging mode, a decrease rate in the battery voltage upon the discharging, and a change magnitude in the open-circuit voltage upon the pausing.

18. The detecting method according to claim 17, wherein on the basis of the shift time to the charging at the constant voltage V_max from the charging at the constant current value I₀, with respect to an increase rate Δ

V_cc/Δ

t per a time (t) in a battery voltage V_cc (in the constant current charging mode) at a t_cc time earlier stage before said shift time, said increase rate Δ

V_cc/Δ

t of the inspective rechargeable battery is compared with that of the normal rechargeable battery;

(v) when said increase rate of the inspective rechargeable battery is greater than that of the normal rechargeable battery, the inspective rechargeable battery is judged to have an increased internal resistance or a decreased electricity storable capacity or an increased internal resistance and a decreased electricity storable capacity; and

(vi) when said increase rate of the inspective rechargeable battery is smaller than that of the normal rechargeable battery, the inspective rechargeable battery is judged to have a decreased internal resistance or to be short-circuited.

19. The detecting method according to claim 1, wherein said given current I_M is in a range of 0.4×

I₀≦

I_M≦

0.6×

I₀ with respect to the current value I₀ upon the constant current charging.

20. The detecting method according to claim 1, wherein said given current I_M is ½

of the current value I₀ upon the constant current charging, i.e., I_M=0.5×

I₀.

21. The detecting method according to claim 2, wherein the inspective rechargeable battery has an electricity storable capacity of D time that the normal rechargeable battery, when with respect to the inspective rechargeable battery, a stored electricity quantity at the shift time to the constant voltage charging at the constant voltage V_max from the constant current charging at the constant current value I₀ is Q₀′

and a period of time until reaching the given current value I_M since said shift time is t_M′

, and with respect to the normal rechargeable battery, aforesaid stored electricity quantity is Q₀and aforesaid time is t_M;

Q₀″

(Q₀″

=Q₀′

/D) which is obtained from the following relation equation (2);

22. The detecting method according to claim 21, wherein said relation formula Voc(Q) and said relation formula R₁₀(Q) of the normal rechargeable battery are selected from previously measured data of the normal rechargeable battery, relation equations obtained from said data, and relation equations obtained based on said measured data by way of simulation by means of a computer.

23. The detecting method according to claim 22, wherein said measured data are averaged data obtained by averaging measured data obtained from a plurality of normal rechargeable batteries which are the same in terms of the type and the kind.

24. The detecting method according to claim 14, wherein after the electricity storable capacity of the inspective rechargeable battery is judged to be D time that of the normal rechargeable battery, presuming that from a correction coefficient f(i, T) which is decided by the electricity storable capacity C_N, the discharge current i and the temperature T of the normal rechargeable battery, a total discharged electricity quantity C_d of the normal rechargeable battery can be expressed by C_d=C_N×

f(i, T) and a total discharged electricity quantity C_d′

of the inspective rechargeable battery is expressed to be C_d′

=D×

C_N×

f(i, T), when for an instrument in which the inspective rechargeable battery is used as a power source, an average consumption current of the instrument is made to be i, an average consumption power of the instrument is made to be p, and an average battery voltage of the inspective rechargeable battery is made to be Vm, a remaining actuation duration h of the instrument is computed in accordance with the equation h=(D×

C_d)/i or h=(Vm×

D×

C_d)/p.

25. The detecting method according to claim 21, wherein presuming that from a correction coefficient f(i, T) which is decided by the electricity storable capacity C_N, the discharge current i and the temperature T of the normal rechargeable battery and also from a correction coefficient r which is proportional to R_I0′

(Q₀′

)/R_I0(Q₀′

) as the internal information relating to the internal resistance which is obtained from the equation (3) defined in claim 21, a total discharged electricity quantity C_d′

of the inspective rechargeable is expressed to be C_d′

=(1/r)×

(D×

C_N)×

f(i, T)=(V_r)×

D×

C_d, when for an instrument in which the inspective rechargeable battery is used as a power source, an average consumption current of the instrument is made to be i, an average consumption power of the instrument is made to be p, and an average battery voltage of the inspective rechargeable battery is made to be Vm, a remaining actuation duration h of the instrument is computed in accordance with the equation h=(1/r)×

(D×

C_d)/i or h=(1/r)×

(Vm×

D×

C_d)/p, where C_d=C_N×

f(i, T).

26. The detecting method according to claim 24 or 25, wherein in the correction coefficient f(i, T) which is decided by the charge current i and the temperature T, previously measured data obtained using the normal rechargeable battery, function equations obtained on the basis of said data, data or function equations with respect to the charge characteristics which are obtained by way of simulation by means of a computer are selectively used.

27. The detecting method according to claim 14, wherein when the D value of the inspective rechargeable battery is less than a given value, the inspective rechargeable battery is judged to be terminated with its lifetime.

28. The detecting method according to claim 1, wherein the rechargeable battery is a rechargeable lithium battery in which oxidation-reduction reaction of lithium is used.

44. A program for detecting internal information of a rechargeable battery, characterized in that said program has a detecting method defined in claim 1 accommodated therein.

45. A memory medium for detecting internal information of a rechargeable battery in which a program defined in claim 44 is stored.

29. A detecting apparatus for detecting internal information of an inspective rechargeable battery when said inspective rechargeable battery is charged by a constant current-constant voltage charging regime in that charging is commenced at a constant current value I₀ and after the battery voltage reaches a given voltage value V_max, the charging is performed at a constant voltage V_max until the termination thereof, said detecting apparatus comprising at least a means for measuring a charge current value I when the inspective rechargeable battery is charged by the constant current-constant voltage charging regime;

a means for measuring an elapse of time (t) from the time when a constant current charging mode at a constant current value I₀ is shifted to a constant voltage charging mode at a constant voltage V_max; and

a means for obtaining a charged electricity quantity by said constant voltage charging mode.

30. The detecting apparatus according to claim 29, wherein said means for obtaining said charged electricity quantity comprises an arithmetic means for obtaining said charged electricity quantity by way of arithmetic operation.

31. The detecting apparatus according to claim 30, wherein said arithmetic means performs arithmetic operation using information of said charge current value I and/or said elapse of time (t).

32. The detecting apparatus according to claim 29 which further comprises a memory means.

33. The detecting apparatus according to claim 32, wherein said memory means has information of the characteristics of a normal rechargeable battery as a reference standard for said inspective rechargeable battery memorized therein.

37. The detecting apparatus according to claim 29 which further comprises a means for outputting or indicating the information acquired from the measuring means and/or information concerning the acquired internal information of the inspective rechargeable battery.

38. A battery pack comprising one or more rechargeable battery units and which has a detecting apparatus defined in claim 29 added thereto.

39. The battery pack according to claim 38, wherein said battery pack has a communication means with an instrument in which said battery pack is used as the power source.

40. The battery pack according to claim 38, wherein said battery pack has a means for outputting or indicating the information acquired from the measuring means and/or information concerning the acquired internal information of the inspective rechargeable battery.

41. A machinery having a detecting apparatus defined in claim 29 added thereto.

42. The machinery according to claim 41, wherein said machinery is selected from the groups consisting of inspection equipments for inspecting a rechargeable battery whether the battery is good or defective, chargers for charging a rechargeable battery, portable instruments (including cellular phones, personal digital assistants, and portable type computers), and movable bodies (including bicycles, automobiles, ships, aircrafts, and space crafts).

43. The machinery according to claim 41, wherein said machinery has a means for outputting or indicating the information acquired from the measuring means and/or information concerning the acquired internal information of the inspective rechargeable battery.

34. A detecting apparatus for detecting internal information of an inspective rechargeable battery when said inspective rechargeable battery is charged by a constant current-constant voltage charging regime in that charging is commenced at a constant current value I₀ and after the battery voltage reaches a given voltage value V_max , the charging is performed at a constant voltage V_max, until the termination thereof, said detecting apparatus comprising at least a means for measuring a charge current value I when said inspective rechargeable battery is charged by the constant current-constant voltage charging regime;

a means for measuring an elapse of time (t) from the time when a constant current charging mode at a constant current value I₀ is shifted to a constant voltage charging mode at a constant voltage V_max;

a means for measuring a time (t_M′

) when the charge current value in said constant voltage charging mode becomes a given current value I_M;

a means for measuring a charged electricity quantity Q_cv′

in said constant voltage charging mode;

a memory means in which an electricity storable capacity C_N of a corresponding normal rechargeable battery as a reference standard for said inspective rechargeable battery and internal information of said normal rechargeable battery when said normal rechargeable battery is charged by the constant current-constant voltage charging regime are memorized, said internal information including a time (t_M) when the charge current value in the constant voltage charging mode becomes a given current value I_M and a charged electricity quantity Q_cv in the constant voltage charging mode; and

an arithmetic means for computing an electricity storable capacity (C_N′

) of the inspective rechargeable battery from said C_N, t_M and Q_cv of the normal rechargeable battery which are memorized in said memory means and said t_M′ and

Q_cv′

detected from the inspective rechargeable battery.

35. A detecting apparatus for detecting internal information of an inspective rechargeable battery when said inspective rechargeable battery is charged by a constant current-constant voltage charging regime in that charging is commenced at a constant current value I₀ and after the battery voltage reaches a given voltage value V_max, the charging is performed at a constant voltage V_max until the termination thereof, said detecting apparatus comprising at least a means for measuring a charge current value I when said inspective rechargeable battery is charged by the constant current-constant voltage charging regime;

a means for measuring an elapse of time (t) from the time when a constant current charging mode at a constant current value I₀ is shifted to a constant voltage charging mode at a constant voltage V_max;

a means for measuring a time (t_M′

) when the charge current value in said constant voltage charging mode becomes a given current value I_M;

a means for measuring a charged electricity quantity Q_cv′

in said constant voltage charging mode;

a memory means in which an electricity storable capacity C_N of a corresponding normal rechargeable battery as a reference standard for said inspective battery and internal information of said normal rechargeable battery when said normal rechargeable battery is charged by the constant current-constant voltage charging regime are memorized, said internal information including the time (t_M) when the charge current value in the constant voltage charging mode becomes a given current value I_M and the charged electricity quantity Q_cv in the constant voltage charging mode; and

a memory means in which further internal information of the normal rechargeable battery is memorized, said further internal information including a relation formula V_oc(Q) of the open-circuit voltage V_oc to the stored electricity quantity Q and a relation formula R_I0(Q) of the internal resistance R_I0 to the stored electricity quantity Q in the constant current charging mode at the constant current value I₀; and

an arithmetic means for acquiring internal information concerning an electricity storable capacity and internal resistance of the inspective rechargeable battery from said measured information of the inspective rechargeable battery and said memorized information concerning the characteristics of the normal rechargeable battery.

36. The detecting apparatus according to claim 35, wherein said relationship Voc(Q) and said relationship R_I0(Q) of the normal rechargeable battery include data table or function formulas previously acquired using the normal rechargeable battery.