Battery management device for electric vehicle
A battery management device to be mounted on an electric vehicle including a driving wheel, a traveling motor configured to generate a driving force for the driving wheel, and a battery configured to store electric power to be consumed by the traveling motor. The battery management device includes a detector configured to detect a state of the battery, and a controller configured to calculate a characteristic value indicating performance of the battery based on an output of the detector, and manage charging and discharging of the battery based on the characteristic value. The controller is configured to, when the characteristic value has deterioration, determine whether the deterioration of the characteristic value is reversible deterioration based on the output of the detector. The controller is configured to, upon determining that the deterioration of the characteristic value is the reversible deterioration, return the characteristic value to a value before the deterioration.
1 . A battery management device to be mounted on an electric vehicle comprising a driving wheel, a traveling motor configured to generate a driving force for the driving wheel, and a battery configured to store electric power to be consumed by the traveling motor, the battery management device comprising:
a detector configured to detect a state of the battery; and
a controller configured to:
calculate, repeatedly, a characteristic value indicating performance of the battery based on an output of the detector;
in response to calculating of the characteristic value, store the calculated characteristic value;
in response to storing of the characteristic value, determine a dV/dQ characteristic line that indicates a relationship between a state of charge (SOC) of the battery and dV/dQ of the battery;
determine whether one or more peaks exist within a predetermined SOC range of the dV/dQ characteristic line, each of the one or more peaks being a point on the dV/dQ characteristic line at which the value of dV/dQ changes from increasing to decreasing;
in response to determining that the one or more peaks exist within the predetermined SOC range of the dV/dQ characteristic line, manage charging and discharging of the battery based on a first characteristic value, the first characteristic value being the last stored characteristic value; and
in response to determining that the one or more peaks do not exist within the predetermined SOC range of the dV/dQ characteristic line, manage the charging and the discharging of the battery based on a second characteristic value, the second characteristic value being (i) the characteristic value stored before the first characteristic value or (ii) the characteristic value calculated after a predetermined time or longer has elapsed from a determination that the one or more peaks do not exist within the predetermined SOC range of the dV/dQ characteristic line.
2 . The battery management device for the electric vehicle according to claim 1 , wherein the controller is further configured to:
determine whether a difference between the first characteristic value and a third characteristic value is equal to or greater than a predetermined first threshold, the third characteristic value being the characteristic value stored before the last stored characteristic value;
in response to determining that the difference is equal to or greater than the predetermined first threshold, perform determination of the dV/dQ characteristic line; and
in response to determining that the difference is not equal to or greater than the predetermined first threshold, skip the determination of the dV/dQ characteristic line.
3 . The battery management device for the electric vehicle according to claim 2 , wherein the controller is further configured to:
even when the controller determines that the one or more peaks exist within the predetermined SOC range of the dV/dQ characteristic line, when a number of the one or more peaks is smaller than a predetermined second threshold, manage charging and discharging of the battery based on the second characteristic value instead of the first characteristic value.
4 . The battery management device for the electric vehicle according to claim 2 , wherein the controller is further configured to:
even when the controller determines that the one or more peaks exist within the predetermined SOC range of the dV/dQ characteristic line, when sharpness of each of the one or more peaks is gentler than a predetermined third threshold, manage the charging and the discharging of the battery based on the second characteristic value instead of the first characteristic value.
5 . The battery management device for the electric vehicle according to claim 1 , wherein the controller is further configured to:
even when the controller determines that the one or more peaks exist within the predetermined SOC range of the dV/dQ characteristic line, when a number of the one or more peaks is smaller than a predetermined second threshold, manage charging and discharging of the battery based on the second characteristic value instead of the first characteristic value.
6 . The battery management device for the electric vehicle according to claim 1 , wherein the controller is further configured to:
even when the controller determines that the one or more peaks exist within the predetermined SOC range of the dV/dQ characteristic line, when sharpness of each of the one or more peaks is gentler than a predetermined third threshold, manage the charging and the discharging of the battery based on the second characteristic value instead of the first characteristic value.
7 . A battery management device to be mounted on an electric vehicle comprising a driving wheel, a traveling motor configured to generate a driving force for the driving wheel, and a battery configured to store electric power to be consumed by the traveling motor, the battery management device comprising circuitry configured to:
detect a state of the battery;
calculate, repeatedly, a characteristic value indicating performance of the battery based on the state of the battery;
in response to calculating of the characteristic value, store the calculated characteristic value;
in response to storing of the characteristic value, determine a dV/dQ characteristic line that indicates a relationship between a state of charge (SOC) of the battery and dV/dQ of the battery;
determine whether one or more peaks exist within a predetermined SOC range of the dV/dQ characteristic line, each of the one or more peaks being a point on the dV/dQ characteristic line at which the value of dV/dQ changes from increasing to decreasing;
in response to determining that the one or more peaks exist within the predetermined SOC range of the dV/dQ characteristic line, manage charging and discharging of the battery based on a first characteristic value, the first characteristic value being the last stored characteristic value; and
in response to determining that the one or more peaks do not exist within the predetermined SOC range of the dV/dQ characteristic line, manage charging and discharging of the battery based on a second characteristic value, the second characteristic value being (i) the characteristic value stored before the last stored characteristic value or (ii) the characteristic value calculated after a predetermined time or longer has elapsed from a determination that the one or more peaks do not exist within the predetermined SOC range of the dV/dQ characteristic line.
8 . A battery management device to be mounted on an electric vehicle comprising a driving wheel, a traveling motor configured to generate a driving force for the driving wheel, and a battery configured to store electric power to be consumed by the traveling motor, the battery management device comprising circuitry configured to:
detect a state of the battery;
determine a first dV/dQ characteristic line that indicates a relationship between a state of charge (SOC) of the battery and dV/dQ of the battery;
store the first dV/dQ characteristic line;
calculate, repeatedly, a characteristic value indicating performance of the battery based on the state of the battery after the first dV/dQ characteristic line is stored;
in response to calculating of the characteristic value, store the calculated characteristic value;
in response to storing of the characteristic value, determine a second dV/dQ characteristic line that indicates the relationship between the state of charge (SOC) of the battery and dV/dQ of the battery;
in response to determining the second dV/dQ characteristic line, determine whether a predetermined condition is satisfied based on a comparison between the stored first dV/dQ characteristic line and the second dV/dQ characteristic line;
in response to determining that the predetermined condition is not satisfied, manage charging and discharging of the battery based on a first characteristic value, the first characteristic value being the last stored characteristic value; and
in response to determining that the predetermined condition is satisfied, manage charging and discharging of the battery based on a second characteristic value, the second characteristic value being (i) the characteristic value stored before the last characteristic value or (ii) the characteristic value calculated after a predetermined time or longer has elapsed from a determination that the predetermined condition is satisfied.
9 . The battery management device for the electric vehicle according to claim 8 , wherein the circuitry is further configured to:
detect one or more first peaks existing within a predetermined SOC range of the first dV/dQ characteristic line;
detect one or more second peaks existing within the predetermined SOC range of the second dV/dQ characteristic line; and
when (i) a number of the one or more second peaks is smaller than a number of the one or more first peaks, and/or (ii) sharpness of each of the one or more second peaks is gentler than sharpness of each of the one or more first peaks, determine that the predetermined condition is satisfied.
10 . The battery management device for the electric vehicle according to claim 9 , wherein the circuitry is further configured to:
determine whether a difference between the first characteristic value and a third characteristic value is equal to or greater than a predetermined first threshold, the third characteristic value being the characteristic value stored before the last stored characteristic value;
in response to determining that the difference is equal to or greater than the predetermined first threshold, perform determination of the second dV/dQ characteristic line; and
in response to determining that the difference is not equal to or greater than the predetermined first threshold, skip the determination of the second dV/dQ characteristic line.
11 . The battery management device for the electric vehicle according to claim 8 , wherein the circuitry is further configured to:
determine whether a difference between the first characteristic value and a third characteristic value is equal to or greater than a predetermined first threshold, the third characteristic value being the characteristic value stored before the last stored characteristic value;
in response to determining that the difference is equal to or greater than the predetermined first threshold, perform determination of the second dV/dQ characteristic line; and
in response to determining that the difference is not equal to or greater than the predetermined first threshold, skip the determination of the second dV/dQ characteristic line.