Battery controller and vehicle system
A battery controller capable of increasing the number of chances of being able to acquire information on a secondary battery storage capacity and a vehicle system having the battery controller mounted thereon are provided. A battery controller 120 mounted on a vehicle system 200 includes a time point setting unit 153 that sets a first time point at which a first voltage difference dVa (=CCVa−OCVa) which is a difference obtained by subtracting a first open-circuit voltage OCVa from a first closed-circuit voltage CCVa is obtained and a second time point at which a second voltage difference dVb (=CCVb−OCVb) which is a difference obtained by subtracting a second open-circuit voltage OCVb from a second closed-circuit voltage CCVb is obtained and an absolute value of the difference from the first voltage difference dVa is equal to or smaller than a predetermined value.
1. A battery controller comprising:
a closed-circuit voltage detection unit that measures a terminal-to-terminal voltage of a secondary battery to acquire a closed-circuit voltage;
an open-circuit voltage calculation unit that performs calculation on the basis of the closed-circuit voltage to acquire an open-circuit voltage;
a time point setting unit that calculates a voltage difference obtained by subtracting the open-circuit voltage from the closed-circuit voltage and sets a first time point and a second time point at which an absolute value of the voltage difference is equal to or smaller than a predetermined value;
a cumulative current amount calculation unit that obtains a cumulative current amount which is a time integrated value of a current flowing through the secondary battery in a period between the first time point and the second time point;
a SOC difference calculation unit that calculates a difference between SOC at the first time point and SOC at the second time point; and
a storage capacity calculation unit that divides the cumulative current amount by the SOC difference to calculate a storage capacity of the secondary battery.
2. The battery controller according to claim 1 , wherein
the time point setting unit calculates the SOC on the basis of the open-circuit voltage and sets the first and second time points at which an absolute value of the SOC difference is equal to or larger than a predetermined value.
3. The battery controller according to claim 1 , wherein
the time point setting unit calculates a current flowing through the secondary battery and sets the first and second time points at which an absolute value of a difference obtained by subtracting the current values is equal to or smaller than a predetermined value.
4. The battery controller according to claim 1 , wherein
the time point setting unit calculates an absolute value of a change over time in the current flowing through the secondary battery and sets the first and second time points at which an absolute value of a change over time in the current flowing through the secondary battery is equal to or smaller than a predetermined value.
5. The battery controller according to claim 1 , wherein
the time point setting unit calculates an absolute value of a current flowing through the secondary battery and sets the first and second time points at which an absolute value of the current flowing through the secondary battery is equal to or smaller than a predetermined value.
6. The battery controller according to claim 1 , wherein
the time point setting unit sets the first and second time points at which a time period is equal to or smaller than a predetermined value.
7. The battery controller according to claim 1 , wherein
the battery controller is mounted on a vehicle system on which a motor generator that is driven by electric power from the secondary battery in a powering mode and generates regenerative power that charges the secondary battery in a regeneration mode and a system control unit that controls the motor generator are mounted.
8. The battery controller according to claim 7 , further comprising:
a command unit that calculates a period elapsed from a time point at which the vehicle system is started and issues a command to perform control of increasing a variation in the SOC to the system control unit when the elapsed period exceeds a predetermined value.
9. The battery controller according to claim 7 , further comprising:
a command unit that issues a command to perform control of increasing a variation in the SOC to the system control unit when the system control unit receives a command to measure the capacitance of the secondary battery from an external capacitance measurement device.
10. The battery controller according to claim 8 , wherein
the vehicle system further has an engine controlled by the system control unit mounted thereon,
the engine and the motor generator drive a driving system, and
the system control unit performs control to increase a variation in the SOC by decreasing motive power to be distributed to the driving system of the engine and increasing motive power to be distributed to the driving system of the motor generator.
11. The battery controller according to claim 8 , wherein
the vehicle system further has an engine controlled by the system control unit mounted thereon, and
the system control unit performs control to increase a variation in the SOC by allowing the motor generator to generate electric power using the motive power of the engine and supplying electric power to the secondary battery.
12. A vehicle system comprising:
the battery controller according to claim 1 ;
a motor generator that is driven by electric power from the secondary battery during a powering mode and generates regenerative power that charges the secondary battery in a regeneration mode; and
a system control unit that controls at least the motor generator.
13. The vehicle system according to claim 12 , wherein
the system control unit calculates a period elapsed from a time point at which the vehicle system is started and performs control to increase a variation in the SOC until the elapsed period exceeds a predetermined value.
14. The vehicle system according to claim 12 , wherein
the system control unit performs control to increase a variation in the SOC upon receiving a command to measure the capacitance of the secondary battery from an external capacitance measurement device.
15. The vehicle system according to claim 13 , further comprising:
an engine controlled by the system control unit, wherein
the engine and the motor generator drive a driving system, and
the system control unit performs control to increase a variation in the SOC by decreasing motive power to be distributed to the driving system of the engine and increasing motive power to be distributed to the driving system of the motor generator.
16. The vehicle system according to claim 13 , further comprising:
an engine controlled by the system control unit, wherein the system control unit performs control to increase a variation in the SOC by allowing the motor generator to generate electric power using the motive power of the engine and supplying electric power to the secondary battery.