NONAQUEOUS ELECTROLYTE TYPE SECONDARY BATTERY SYSTEM AND VEHICLE

• US 20110270477A1
• Filed: 01/08/2009
• Published: 11/03/2011
• Est. Priority Date: 01/08/2009
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ueki, Tomoyoshi
• Granted Patent: US 8,803,482 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/44 Methods for charging or discharging 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: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H02J 7/007 Regulation of charging or discharging current or voltage
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A purpose is to provide a nonaqueous electrolyte type lithium ion secondary battery system, a control method, and a vehicle using the system, arranged to prevent unevenness of a salt concentration distribution in an electrolyte, avoiding an increase in internal resistance, thus improving endurance of the nonaqueous electrolyte type lithium ion secondary battery. For a measuring time (S101 to S104), a charge threshold current Ic and a discharge threshold current Id are read out (S102) and a charge hysteresis value Cc and a discharge hysteresis value Cd are calculated (S103). The charge hysteresis value Cc and the discharge hysteresis value Cd are compared (S105). If the charge hysteresis value Cc is larger than the discharge hysteresis value Cd (S105: Yes), a current value on a charge side is limited (S106). To the contrary, if the charge hysteresis value Cc is equal to or smaller than the discharge hysteresis value Cd (S105: No), a current value on a discharge side is limited (S107).

Claims

1. A nonaqueous electrolyte type secondary battery system comprising:

a nonaqueous electrolyte type secondary battery; and

a control part for controlling the nonaqueous electrolyte type secondary battery, wherein

the control part includes;

a charge and discharge hysteresis value calculating part for calculating, at predetermined time intervals,

a charge hysteresis value Cc representing a history of charge with a current exceeding a predetermined charge threshold current Ic, and

a discharge hysteresis value Cd representing a history of discharge with a current exceeding a predetermined discharge threshold current Id; and

a current limiting part for limiting the charge current or the discharge current after a difference between the charge hysteresis value Cc and the discharge hysteresis value Cd is determined to be larger than a predetermined degree,

the current limiting part is arranged to;

limit the charge current when the charge hysteresis value Cc is larger than the discharge hysteresis value Cd, and

limit the discharge current when the charge hysteresis value Cc is smaller than the discharge hysteresis value Cd.

2. The nonaqueous electrolyte type secondary battery system according to claim 1, wherein the nonaqueous electrolyte type secondary battery is a nonaqueous electrolyte type lithium ion secondary battery.

3. The nonaqueous electrolyte type secondary battery system according to claim 1, wherein

the current limiting part is adapted to:

limit the charge current when the charge hysteresis value Cc is equal to or larger than a value calculated by adding a predetermined positive reference value to the discharge hysteresis value Cd; and

limit the discharge current when the discharge hysteresis value Cd is equal to or larger than a value calculated by adding a predetermined positive reference value to the charge hysteresis value Cc.

4. The nonaqueous electrolyte type secondary battery system according to claim 1, wherein

the current limiting part is adapted to:

limit the charge current when a ratio of the charge hysteresis value Cc to the discharge hysteresis value Cd is larger than a first reference value that is a predetermined number equal to or larger than 1; and

limit the discharge current when a ratio of the discharge hysteresis value Cd to the charge hysteresis value Cc is larger than a second reference value that is a predetermined number equal to or larger than 1.

5. The nonaqueous electrolyte type secondary battery system according to claim 4, wherein

the current limiting part performs no current limiting

when the ratio of the charge hysteresis value Cc to the discharge hysteresis value Cd is equal to or smaller than the first reference value, and the ratio of the discharge hysteresis value Cd to the charge hysteresis value Cc is equal to or smaller than the second reference value.

6. The nonaqueous electrolyte type secondary battery system according to claim 1, wherein

the charge and discharge hysteresis value calculating part uses,

as the charge hysteresis value Cc, a value defined by the following expression:

Cc=|∫

[I(t)−

Ic(t)]dt|

where an integral interval is an interval of time “

t”

in which I(t)≧

Ic(t) is established, and

Ic(t) is a predetermined threshold current, and

as the discharge hysteresis value Cd, a value defined by the following expression;

Cd=|∫

[I(t)−

Id(t)]dt|

where an integral interval is an interval of time “

t”

in which I(t)≦

Id(t) is established, and

Id(t) is a predetermined threshold current.

7. The nonaqueous electrolyte type secondary battery system according to claim 1, wherein

the charge and discharge hysteresis value calculating part uses,

as the charge hysteresis value Cc, a value defined by the following expression:

Cc=|∫

I(t)dt|

where an integral interval is an interval of time “

t”

in which I(t)≧

Ic(t) is established, and

Ic(t) is a predetermined threshold current, and

as the discharge hysteresis value Cd, a value defined by the following expression;

Cd=|∫

I(t)dt|

where an integral interval is an interval of time “

t”

in which I(t)≦

Id(t) is established, and

Id(t) is a predetermined threshold current.

8. The nonaqueous electrolyte type secondary battery system according to claim 1, wherein

the charge and discharge hysteresis value calculating part uses,

as the charge hysteresis value Cc, a value defined by the following expression:

Cc=Ic·

Tc

where Tc is a time in which I(t)≧

Ic was established, and

as the discharge hysteresis value Cd, a value defined by the following expression;

Cd=Id·

Td

where Td is a time in which I(t)≦

Id was established.

9. The nonaqueous electrolyte type secondary battery system according to claim 1, wherein

the charge and discharge hysteresis value calculating part uses,

as the charge hysteresis value Cc, a value defined by the following expression:

Cc=Imax·

Tc

where Tc is a time in which I(t)≧

Ic was established, and

Imax;

a maximum current value within the measuring time, and

as the discharge hysteresis value Cd, a value defined by the following expression;

Cd=Imin·

Td

where Td is a time in which I(t)≦

Id was established,

Imin;

a minimum current value within the measuring time.

10. The nonaqueous electrolyte type secondary battery system according to claim 1, wherein

the charge and discharge hysteresis value calculating part uses,

as the charge hysteresis value Cc, a time Tc in which I(t)≧

Ic was established, and

as the discharge hysteresis value Cd, a time Td in which I(t)≦

Id was established.

11. The nonaqueous electrolyte type secondary battery system according to claim 6, wherein

the charge and discharge hysteresis value calculating part uses,

as the charge hysteresis value Cc, an accumulated hysteresis value SCc calculated by adding a currently calculated charge hysteresis value Cc to a sum of charge hysteresis values Cc calculated previously, and

as the discharge hysteresis value Cd, an accumulated hysteresis value SCd calculated by adding a currently calculated discharge hysteresis value Cd to a sum of discharge hysteresis values Cd calculated previously.

12. The nonaqueous electrolyte type secondary battery system according to claim 1, wherein

when a current value when the current limiting is assumed not performed exceeds a predetermined limit value, the current limiting part flows a current of the limit value instead of the current value with no current limiting.

13. The nonaqueous electrolyte type secondary battery system according to claim 1, wherein

the current limiting part flows a current of a value calculated by multiplying a current value when the current limiting is assumed not performed by a predetermined coefficient smaller than 1.

14. The nonaqueous electrolyte type secondary battery system according to claim 1, wherein

when a current value when the current limiting is assumed not performed exceeds a predetermined limit value,

the current limiting part flows a current corresponding to a sum of a value calculated by multiplying an excess amount of the current value exceeding the limit value by a predetermined coefficient smaller than 1 and the limit value instead of the current value with no current limiting.

15. The nonaqueous electrolyte type secondary battery system according to claim 1, wherein the current limiting part sets,

for limiting the charge current, a value of the discharge threshold current Id to be used in a next measurement to be larger than a value in a previous measurement, and

for limiting the discharge current, a value of the charge threshold current Ic to be used in the next measurement to be larger than a value in the previous measurement.

16. The nonaqueous electrolyte type secondary battery system according to claim 1, wherein

the charge and discharge hysteresis value calculating part uses,

as the charge threshold current Ic,

a smaller value in absolute value as an SOC (State of Charge) value is larger and a larger value in absolute value as the SOC value is smaller, and

a larger value in absolute value as a battery temperature is higher and a smaller value in absolute value as the battery temperature is lower, and

as the discharge threshold current Id,

a larger value in absolute value as the SOC value is larger and a smaller value in absolute value as the SOC value is smaller, and

a larger value in absolute value as the battery temperature is higher and a smaller value in absolute value as the battery temperature is lower.

20. The nonaqueous electrolyte type secondary battery system according to claim 2, wherein

the current limiting part is adapted to:

limit the charge current when the charge hysteresis value Cc is equal to or larger than a value calculated by adding a predetermined positive reference value to the discharge hysteresis value Cd; and

limit the discharge current when the discharge hysteresis value Cd is equal to or larger than a value calculated by adding a predetermined positive reference value to the charge hysteresis value Cc.

17. A vehicle comprising:

a motor;

a nonaqueous electrolyte type secondary battery; and

a control part for controlling the nonaqueous electrolyte type secondary battery, wherein

the control part includes;

a charge and discharge hysteresis value calculating part for calculating, at predetermined time intervals,

a charge hysteresis value Cc representing a history of charge with a current exceeding a predetermined charge threshold current Ic, and

a discharge hysteresis value Cd representing a history of discharge with a current exceeding a predetermined discharge threshold current Id; and

a current limiting part for limiting the charge current or the discharge current after a difference between the charge hysteresis value Cc and the discharge hysteresis value Cd is determined to be larger than a predetermined degree,

the current limiting part is arranged to;

limit the charge current when the charge hysteresis value Cc is larger than the discharge hysteresis value Cd, and

limit the discharge current when the charge hysteresis value Cc is smaller than the discharge hysteresis value Cd.

18. A nonaqueous electrolyte type secondary battery system comprising:

a nonaqueous electrolyte type secondary battery; and

a control part for controlling the nonaqueous electrolyte type secondary battery, wherein

the control part includes;

a charge and discharge hysteresis value calculating part for calculating, at predetermined time intervals,

a charge hysteresis value Cc representing a history of charge with a current exceeding a predetermined charge threshold current Ic, and

a discharge hysteresis value Cd representing a history of discharge with a current exceeding a predetermined discharge threshold current Id; and

a salt concentration estimating part for estimating a salt concentration distribution in an electrolyte of the nonaqueous electrolyte type secondary battery based on the charge hysteresis value Cc and the discharge hysteresis value Cd.

19. A vehicle comprising:

a motor;

a nonaqueous electrolyte type secondary battery; and

a control part for controlling the nonaqueous electrolyte type secondary battery, wherein

the control part includes;

a charge and discharge hysteresis value calculating part for calculating, at predetermined time intervals,

a charge hysteresis value Cc representing a history of charge with a current exceeding a predetermined charge threshold current Ic, and

a discharge hysteresis value Cd representing a history of discharge with a current exceeding a predetermined discharge threshold current Id; and

a salt concentration estimating part for estimating a salt concentration distribution in an electrolyte of the nonaqueous electrolyte type secondary battery based on the charge hysteresis value Cc and the discharge hysteresis value Cd.