Detecting method and detecting apparatus for detecting internal of rechargeable battery, rechargeable battery pack having said detecting apparatus therein, apparatus having said detecting apparatus therein, program in which said detecting method is incorporated, and medium in which said program is stored

• US 7,190,171 B2
• Filed: 10/10/2003
• Issued: 03/13/2007
• Est. Priority Date: 10/11/2002
• 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): TIBBITS, PIA FLORENCE
• Application Number:
  US10/682,454
• Publication Number:
  US 20050035743A1
• Time in Patent Office: 1,250 Days
• Field of Search: 324/430, 324/426, 324/427, 320/141, 320/149, 320/152
• US Class Current: 324/430
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: H01M 10/46 Accumulators structurally combined with charging apparatus circuits for charging H02J7/00
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A detecting method for detecting internal resistance of an inspective rechargeable battery when said inspective rechargeable battery is charged by the constant current-constant voltage charging regime, said detecting method comprising at least a step (a) wherein an accumulated, charged electricity quantity of said inspective rechargeable battery in the constant voltage charging mode is obtained and a step (b) wherein said charged electricity quantity of said inspective rechargeable battery obtained in the constant voltage charging mode in said step (a) is referred to previously acquired data of a normal rechargeable battery, which corresponds to said inspective rechargeable battery, with respect to relationships of charged electricity quantities Q_cv thereof versus internal resistances thereof when increased or decreased or their increased or decreased magnitudes in the constant voltage charging mode.

Claims

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

(a) obtaining an accumulated, charged electricity quantity of said inspective rechargeable battery in said constant voltage charging mode; and

(b) comparing said charged electricity quantity obtained in said step (a) to previously acquired data of a normal rechargeable battery in said constant voltage charging mode, said normal rechargeable battery corresponding to said inspective rechargeable battery,

wherein said previously acquired data are with respect to relationships between charged electricity quantities Q_cv of said normal rechargeable battery and increased or decreased internal resistances of said normal rechargeable battery or between said charged electricity quantities Q_cv and increased or decreased magnitudes of said internal resistances,

wherein when said inspective rechargeable battery has an electricity storable capacity which is reduced to a magnitude of D time that of said normal rechargeable battery, where D is a constant of 0<

D≦

1, said detecting method further includes a step of correcting said charged electricity quantity obtained in said step (a) by multiplying said charged electricity quantity by 1/D time, wherein the corrected electrical quantity is compared to said previously acquired data of said normal rechargeable battery described in said step (b), and

wherein in a case where it is presumed that said electricity storable capacity of said inspective rechargeable battery is reduced to a magnitude of D time that of said normal rechargeable battery, when a duration from a shift time when said constant current charging mode at said constant current value I₀ is shifted to said constant voltage charging mode at said constant voltage V_max until a time when the charging current value in said constant voltage charging mode reaches a prescribed current value I_M and an electricity quantity charged in said constant voltage charging mode are made to be respectively t_M′ and

Q_cv′

for said inspective rechargeable battery and t_M and Q_cv for said normal rechargeable battery, in accordance with a function formula D=(Q_cv′

−

I₀×

t_M′

)/(Q_cv−

I₀×

t_M), said electricity storable capacity of said inspective rechargeable battery is estimated to be D time that of said normal rechargeable battery.

2. The detecting method according to claim 1, wherein said inspective rechargeable battery is a rechargeable battery accommodated in a rechargeable battery pack having a control circuit in which one or more of a switching element for charging which is capable of performing ON-OFF control, a switching element for discharging, and a detecting element for detecting a charging-and-discharging current value is accommodated in a charging-and-discharging path of said rechargeable battery accommodated in said rechargeable battery pack.

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

I₀≦

I_M≦

0.6×

I₀ with respect to said charging current value I₀ in the constant current charging mode.

4. The detecting method according to claim 3, wherein said prescribed current value I_M is a ½

of said current value I₀.

5. The detecting method according to claim 1, wherein said previously acquired data of said normal rechargeable battery include previously measured data of said relationships of said 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.

6. The detecting method according to claim 5, wherein said previously acquired data of said normal rechargeable battery include data of relationships between said charged electricity quantities Q_cv of said normal rechargeable battery and resistance values r_s based on resistors or include data of relationships between said charged electricity quantities Q_cv and internal resistance values (R₁+r_s) of said normal rechargeable battery, wherein said data of relationships between said charged electricity quantities Q_cv and said internal resistance values (R₁+r_s) are obtained by a method wherein each of a plurality of resistors each having a different resistance value (r_s) is separately connected to said normal rechargeable battery in series connection to artificially increase an internal resistance value (R₁) of said normal rechargeable battery to a resistance value (R₁+r_s) as an artificially internal resistance value, wherein in each case where one of said plurality of resistors is connected to said normal rechargeable battery, said normal rechargeable battery is charged by said constant current-constant voltage charging regime comprising said constant current charging mode and said constant voltage charging mode in that charging is commenced by said constant current charging mode at said constant current value I₀ and after the battery voltage of said normal rechargeable battery reaches said given voltage value V_max, the charging is performed by said constant voltage charging mode at said constant voltage V_max until the termination thereof, and wherein in each case where one of said plurality of resistors is connected to said normal rechargeable battery, a charged electricity quantity Q_cv of said normal rechargeable battery is measured and a relationship between said charged electricity quantity Q_cv and said artificially internal resistance value of said normal rechargeable battery is obtained.

7. The detecting method according to claim 6, wherein said resistance value (r_s) of each of said plurality of resistors is of substantially the same order as said internal resistance value R₁ of said normal rechargeable battery or said resistance value (r_s) of each of said plurality of resistors differs from said internal resistance value R₁ by one digit.

8. The detecting method according to claim 6, wherein in each case where one of said plurality of resistors is connected to said normal rechargeable battery, an open-circuit voltage Voc of said normal rechargeable battery when the battery voltage reaches said voltage value V_max is measured and a charged electricity quantity Q_cv of said normal rechargeable battery in said constant voltage charging mode at that time is measured, and from said constant current value I₀ in said constant current charging mode, said measured open-circuit voltage Voc and said measured charged electricity quantity Q_cv and from a function formula R=(V_max−

Voc)/I₀, an internal resistance value of said normal rechargeable battery whose internal resistance value is artificially increased to (R₁+r_s) is computed, and a relationship between said measured charged electricity quantity Q_cv and said computed internal resistance value of said normal rechargeable battery is obtained.

9. The detecting method according to claim 1, wherein a time point when said charged electricity quantity of said inspective rechargeable battery in said constant voltage charging mode is measured is any of the following three time points:

(1) a time point when the charging current in said constant voltage charging mode is sufficiently decreased to a prescribed current value (I_min);

(2) a time point when a prescribed time (t_n) elapses since the time when the charging current value in said constant voltage charging mode reaches a prescribed current value (I_n); and

(3) a time point when a prescribed time (t_f) elapses since the time when said constant current charging mode is shifted to said constant voltage charging mode.

10. The detecting method according to claim 1, wherein after said internal resistance of said inspective rechargeable battery is predicted to be R on the basis of said previously acquired data, it is presumed that a total discharged electricity quantity C_d of said normal rechargeable battery whose internal resistance is R₁ is expressed by C_d=C_N×

f<sub>—

T,I</sub>(R₁) from an electricity storable capacity C_N of said normal rechargeable battery and a correction coefficient f<sub>—

T,I</sub>(R₁) for a discharged electricity quantity of said normal rechargeable battery which is determined by said internal resistance R₁ at a battery temperature T and a discharging current I, and wherein in a case where electricity storable capacity is not reduced in said inspective rechargeable battery, a total discharged electricity quantity C_d′

of said inspective rechargeable battery is expressed by C_d′

=C_N×

f<sub>—

T,I</sub>(R) from said electricity storable capacity C_N of said normal rechargeable battery and a correction coefficient f<sub>—

T,I</sub>(R) for a discharged quantity of said normal rechargeable battery having said internal resistance value R at a battery temperature T and a discharging current I, with said internal resistance value R being computed by artificially increasing R₁ by a magnitude of r_s, and wherein when for an instrument in which said inspective rechargeable battery is used as a power source, an average consumption electric current of the instrument is made to be i, an average consumption power of the instrument is made to be p, an average discharging voltage of said normal rechargeable battery when it is discharged at a discharging current value i is made to be V_m, and an average discharging voltage of said inspective rechargeable battery when it is discharged at said discharging current value i is made to be V_m′

, a time h during which said instrument is capable of being operated is computed in accordance with an equation

h=C_d′

/i or h=(V_m′

×

C_d′

)/p, where V_m′

=V_m−

i×

(R−

R₁)=V_m−

i×

r_s.

11. The detecting method according to claim 10, wherein said correction coefficient f_T,I(R₁) for said discharged electricity quantity of said normal rechargeable battery is selected from (i) previously acquired data relating to correction coefficients for discharged electricity quantities and (ii) function formulas obtained by simulation by a computer based on said previously acquired data relating to correction coefficients.

12. The detecting method according to claim 11, wherein said previously acquired data of said normal rechargeable battery include data of relationships between internal resistance values (R₁+r_s) and discharged electricity quantities C_d of said normal rechargeable battery, wherein said internal resistance values (R₁+r_s) and said discharged electrical quantities C_d are obtained by a method wherein each of a plurality of resistors each having a different resistance value (r_s) is separately connected to said normal rechargeable battery in series connection to artificially increase said internal resistance value (R₁) of said normal rechargeable battery to a resistance value (R₁+r_s) as an artificially increased resistance value, and wherein in each case where one of said plurality of resistors is connected to said normal rechargeable battery, said normal rechargeable battery is charged by said constant current-constant voltage charging regime comprising said constant current charging mode and said constant voltage charging mode in that charging is commenced by said constant current charging mode at said constant current value I₀ and after the battery voltage of said normal rechargeable battery reaches said given voltage value V_max, the charging is performed by said constant voltage charging mode at said constant voltage V_max until the termination thereof and after the charging is terminated, said normal rechargeable battery is discharged at a prescribed battery temperature T and a prescribed discharging current value I until the battery voltage of said normal rechargeable battery reaches a prescribed voltage value V_min, where a discharged electricity quantity C_d is measured, and a relationship between said measured discharged electricity quantity C_d and said artificially increased internal resistance value of said normal rechargeable battery is obtained.

13. The detecting method according to claim 12, wherein said resistance value (r_s) of each of said plurality of resistors is of substantially the same order as said internal resistance value R₁ of said normal rechargeable battery or said resistance value (r_s) of said plurality of resistors differs from said internal resistance value R₁ by one digit.

14. The detecting method according to claim 11, wherein said previously acquired data of said normal rechargeable battery include data of relationships between internal resistance values (R₁+r_s) and discharged electricity quantities C_d of said normal rechargeable battery, wherein said internal resistance values (R₁+r_s) and said discharged electricity quantities C_d are obtained by a method wherein each of a plurality of resistors each having a different resistance value (r_s) is separately connected to said normal rechargeable battery in series connection to artificially increase an internal resistance value (R₁) of said normal rechargeable battery to a resistance value (R₁+r_s) as a pseudo-internal resistance value, and wherein in each case where one of said plurality of resistors is connected to said normal rechargeable battery, said normal rechargeable battery is charged by said constant current-constant voltage charging regime comprising said constant current charging mode and said constant voltage charging mode in that charging is commenced by said constant current charging mode at said constant current value I₀ and after the battery voltage of said normal rechargeable battery reaches said given voltage value V_max, the charging is performed by said constant voltage charging mode at said constant voltage V_max until the termination thereof and after the charging is terminated, said normal rechargeable battery is discharged at a prescribed battery temperature T and a prescribed discharging current value I until the battery voltage of said normal rechargeable battery reaches a prescribed voltage value V_min, where a discharged electricity quantity C_d of said normal rechargeable battery is measured, and an open-circuit voltage Voc of said normal rechargeable battery when the battery voltage reaches said voltage value V_max in said constant current-constant voltage charging operation is measured, and from said constant current value I₀ in the constant current charging mode and said measured open-circuit voltage Voc and in accordance with a function formula R=(V_max−

Voc)/I₀, an internal resistance value of said normal rechargeable battery whose internal resistance value is artificially increased to R, with R equaling R₁+r_s, is computed, and a relationship between said measured discharged electricity quantity C_d and said computed internal resistance value R of said normal rechargeable battery is obtained.

15. The detecting method according to claim 14, wherein said resistance value (r_s) of each of said plurality of resistors is of substantially the same order as said internal resistance value R₁ of said normal rechargeable battery or said resistance value (r_s) of said plurality of resistors differs from said internal resistance value R₁ by one digit.

16. The detecting method according to claim 10, wherein in a case where said inspective rechargeable battery has an electricity storable capacity which is reduced to a magnitude of D time that of said normal rechargeable battery, where D is a constant of 0<

D≦

1, it is presumed that said total discharged electricity quantity C_d′

of said inspective rechargeable battery is expressed by C_d′

=D×

C_N×

f<sub>—

T,I</sub>(R) from said electricity storage capacity C_N of said normal rechargeable battery and said correction coefficient f<sub>—

T,I</sub>(R).

17. The detecting method according to claim 16, wherein said prescribed current value I_M is in a range of 0.4×

I₀≦

I_M≦

0.6×

10.

18. The detecting method according to claim 16, wherein said prescribed current value I_M is ½

of said constant current value I₀ in said constant current charging mode.

26. The detecting method according to claim 12, wherein said previously acquired data of said normal rechargeable battery include data of a relationship between said internal resistance value R₁ and a discharged electrical quantity C_d, which are obtained by charging said normal rechargeable battery by said constant current-constant voltage charging regime without a resistor being connected to said normal rechargeable battery, such that said correction coefficient f_—

T,I(R₁) becomes C_d/C_N.

27. The detecting method according to claim 14, wherein said previously acquired data of said normal rechargeable battery include data of a relationship between said internal resistance value R₁ and a discharged electrical quantity C_d, which are obtained by charging said normal rechargeable battery by said constant current-constant voltage charging regime without a resistor being connected to said normal rechargeable battery, such that said correction coefficient f_—

T,I(R₁) becomes C_d/C_N.

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

(i) means for measuring a voltage of said inspective rechargeable battery;

(ii) means for acquiring an accumulated, charged electricity quantity of said inspective rechargeable battery in said constant voltage charging mode;

(iii) means for memorizing previously acquired data of a normal rechargeable battery in said constant voltage charging mode, said normal rechargeable battery corresponding to said inspective rechargeable battery, wherein said previously acquired data are with respect to relationship between charged electricity quantities of said normal rechargeable battery and increased or decreased internal resistances of said normal rechargeable battery or increased or decreased magnitudes of said internal resistances; and

(iv) means for comparing said charged electricity quantity obtained by said means (ii) to said previously acquired data memorized by said means (iii), wherein internal resistance of said inspective rechargeable battery is detected from said previously acquired data memorized by said means (iv),

wherein in a case where said inspective rechargeable battery has an electricity storable capacity which is reduced to a magnitude of D time that of said normal rechargeable battery, where D is a constant of 0<

D≦

I, said detecting apparatus has a further means for correcting said charged electricity quantity by multiplying said charged electricity quantity by 1/D time prior to comparison by said means (iv), and

wherein in a case where it is presumed that said electricity storable capacity of said inspective rechargeable battery is reduced to a magnitude of D time that of said normal rechargeable battery, when a duration from a shift time when said constant current charging mode at said constant current value I₀ is shifted to said constant voltage charging mode at said constant voltage V_max until a time when the charging current value in said constant voltage charging mode reaches a prescribed current value I_M and an electricity quantity charged in said constant voltage charging mode are made to be respectively t_M′ and

Q_cv′

for said inspective rechargeable battery and t_M and Q_cv for said normal rechargeable battery, in accordance with a function formula D=(Q_cv′

−

I₀×

t_M′

)/(Q_cv−

I₀×

t_M), said electricity storable capacity of said inspective rechargeable battery is estimated to be D time that of said normal rechargeable battery.

20. The detecting apparatus according to claim 19, wherein said inspective rechargeable battery is a rechargeable battery accommodated in a rechargeable battery pack.

21. The detecting apparatus according to claim 20, wherein said rechargeable battery pack has a control circuit in which at least one of a switching element for charging which is capable of performing ON-OFF control, a switching element for discharging, and a detecting element for detecting a charge-and-discharge current value is accommodated in a charging-and-discharging path of said rechargeable battery accommodated in said rechargeable battery pack.

22. A rechargeable battery pack in which a detecting apparatus defined in claim 19 is accommodated.

23. An apparatus having a detecting apparatus defined in claim 19 added thereto.

24. The apparatus according to claim 23, wherein said apparatus having the detecting apparatus added thereto is selected from the group consisting of inspection equipment for inspecting whether a rechargeable battery is good or defective, chargers for charging a rechargeable battery, portable instruments, and movable bodies.

25. The apparatus according to claim 24, wherein said portable instruments are selected from the group consisting of cellular phones, personal digital assistants, and portable type computers, and wherein said movable bodies are selected from the group consisting of motorcycles, automobiles, ships, aircrafts, and space crafts.

29. The detecting apparatus according to claim 19, wherein said previously acquired data of said normal rechargeable battery include data of relationships between said charged electricity quantities Q_cv of said normal rechargeable battery and resistance values r_s based on resistors or include data of relationships between said charged electricity quantities Q_cv and internal resistance values (R₁+r_s) of said normal rechargeable battery, wherein said data of relationships between said charged electricity quantities Q_cv and said internal resistance values (R₁+r_s) are obtained by a method wherein each of a plurality of resistors each having a different resistance value (r_s) is separately connected to said normal rechargeable battery in series connection to artificially increase an internal resistance value (R₁) of said normal rechargeable battery to a resistance value (R₁+r_s) as an artificially internal resistance value, wherein in each case where one of said plurality of resistors is connected to said normal rechargeable battery, said normal rechargeable battery is charged by said constant current-constant voltage charging regime comprising said constant current charging mode and said constant voltage charging mode in that charging is commenced by said constant current charging mode and said constant current value I₀ and after the battery voltage of said normal rechargeable battery reaches said given voltage value V_max, the charging is performed by said constant voltage charging mode at said constant voltage V_max until the termination thereof, and wherein in each case where one of said plurality of resistors is connected to said normal rechargeable battery, a charged electricity quantity Q_cv of said normal rechargeable battery is measured and a relationship between said charged electricity quantity Q_cv and said artificially internal resistance value of said normal rechargeable battery is obtained.

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

(a) obtaining an accumulated, charged electricity quantity of said inspective rechargeable battery in said constant voltage charging mode; and

(b) comparing said charged electricity quantity obtained in said step (a) to previously acquired data of a normal rechargeable battery in said constant voltage charging mode, said normal rechargeable battery corresponding to said inspective rechargeable battery,

wherein said previously acquired data are with respect to relationships between charged electricity quantities Q_cv of said normal rechargeable battery and increased or decreased internal resistances of said normal rechargeable battery or between said charged electricity quantities Q_cv and increased or decreased magnitudes of said internal resistances,

wherein said previously acquired data of said normal rechargeable battery include previously measured data of said relationships of said 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,

wherein said previously acquired data of said normal rechargeable battery include data of relationships between said charged electricity quantities Q_cv of said normal rechargeable battery and resistance values r_s based on resistors or include data of relationships between said charged electricity quantities Q_cv and internal resistance values (R₁+r_s) of said normal rechargeable battery,

wherein said data of relationships between said charged electricity quantities Q_cv and said internal resistance values (R₁+r_s) are obtained by a method wherein each of a plurality of resistors each having a different resistance value (r_s) is separately connected to said normal rechargeable battery in series connection to artificially increase an internal resistance value (R₁) of said normal rechargeable battery to a resistance value (R₁+r_s) as an artificially internal resistance value,

wherein in each case where one of said plurality of resistors is connected to said normal rechargeable battery, said normal rechargeable battery is charged by said constant current-constant voltage charging regime comprising said constant current charging mode and said constant voltage charging mode in that charging is commenced by said constant current charging mode at said constant current value I₀ and after the battery voltage of said normal rechargeable battery reaches said given voltage value V_max, the charging is performed by said constant voltage charging mode at said constant voltage V_max until the termination thereof, and

wherein in each case where one of said plurality of resistors is connected to said normal rechargeable battery, a charged electricity quantity Q_cv of said normal rechargeable battery is measured and a relationship between said charged electricity quantity Q_cv and said artificially internal resistance value of said normal rechargeable battery is obtained.